CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. application Ser. No. 13/411,134 filed on Mar. 2, 2012 which is based upon and claims the benefit of priority of PCT Application No. PCT/JP2010/059968 filed on Jun. 11, 2010, the entire contents of each of which are incorporated herein by reference. The present application is based upon and claims the benefit of priority of Japanese Patent Application Laid-open No. 2010-121919, filed on May 27, 2010, Japanese Patent Application Laid-open No. 2010-121974, filed on May 27, 2010, Japanese Patent Application Laid-open No. 2010-121808, filed on May 27, 2010, Japanese Patent Application Laid-open No. 2009-204459, filed on Sep. 4, 2009, Japanese Patent Application Laid-open No. 2009-204403, filed Sep. 4, 2009, and Japanese Patent Application Laid-open No. 2009-204368, filed on Sep. 4, 2009, the entire contents of each of which are incorporated herein by reference. The present application further incorporates herein by reference the entire contents of the U.S. Patent Application Publication No. 2006/0034642, filed Feb. 16, 2006, and U.S. Patent Application Publication No. 2004/0223790, filed on Nov. 11, 2004. 
     
    
     FIELD 
       [0002]    The present invention relates to a toner container for use in a copier, a printer, or an image forming apparatus such as a multifunction peripheral that has the functions of a copier, a printer, and/or a facsimile machine, and relates to an image forming apparatus including the toner container. 
       BACKGROUND 
       [0003]    In conventional image forming apparatuses such as copiers, a cylindrical toner container (a toner bottle) that is detachably attached to a main body of an image forming apparatus has been widely used (see, for example, Patent Document 1 and Patent Document 2). Patent Documents 1 and 2 disclose a toner container (a toner bottle) that is set in a body of an image forming apparatus in a replaceable manner and that mainly includes a container body (a bottle body) and a cap unit (a held unit).
   Patent Document 1: Japanese Patent Application Laid-open No. H4-1681   Patent Document 2: Japanese Patent Application Laid-open No. 2002-268344   
 
       SUMMARY 
       [0006]    A toner container detachably attached to a body of an image forming apparatus that includes a first holding member, a second holding member, and a shutter closing mechanism such that a longitudinal direction of the toner container is kept horizontal includes: a toner outlet for discharging toner; a shutter unit that moves along an outer periphery of the toner container to open and close the toner outlet; a shutter rail for guiding the shutter unit to move in the longitudinal direction for opening and closing the toner outlet; and a projection that protrudes from the toner container in the longitudinal direction so as to protrude from an end portion of the shutter unit in a closing direction with the end portion located at a position where the toner outlet is closed. The shutter rail has two surface members that are disposed, respectively, on one side and another side of the toner container, and are extending in the longitudinal direction, the projection has surfaces that are respectively in the same planes as planes of the surface members of the shutter rail, the toner outlet is opened and closed by moving the shutter unit on the shutter rail, the surface members are to be sandwiched by the first holding member, the shutter unit is switched between a held state in which the shutter unit is held by the second holding member and a released state in which holding of the shutter unit by the second holding member is released in accordance with rotation of the second holding member, and the shutter unit is prevented by the shutter closing mechanism, which makes the second holding member incapable of rotating, from being open while the surface members are sandwiched by the first holding member. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0007]      FIG. 1  is an overall configuration diagram of an image forming apparatus according to a first embodiment of the present invention; 
           [0008]      FIG. 2  is a cross-sectional view of an image forming unit; 
           [0009]      FIG. 3  is a schematic diagram of how a toner container is set in a toner supply device; 
           [0010]      FIG. 4  is a schematic perspective view of how toner containers are set in a toner-container holder. 
           [0011]      FIG. 5  is a perspective view of the toner container viewed obliquely from above; 
           [0012]      FIG. 6  is a perspective view of the toner container viewed obliquely from below; 
           [0013]      FIG. 7  illustrates six sides of the toner container; 
           [0014]      FIG. 8  is a front view of the toner container viewed from a cap unit side; 
           [0015]      FIG. 9  is an exploded view of the toner container; 
           [0016]      FIG. 10  is a perspective view of a container body of the toner container; 
           [0017]      FIG. 11  is a perspective view of a cap unit of the toner container; 
           [0018]      FIG. 12  is another perspective view of the cap unit of the toner container; 
           [0019]      FIG. 13  is a perspective view of the cap unit of the toner container when viewed from a side of the cap unit to which the container body is connected; 
           [0020]      FIG. 14  is another perspective view of the cap unit of the toner container when viewed from the side of the cap unit to which the container body is connected; 
           [0021]      FIG. 15  is a perspective view of a state in which a shutter unit of the toner container closes a toner outlet; 
           [0022]      FIG. 16  is a perspective view of how the shutter unit of the toner container opens the toner outlet; 
           [0023]      FIG. 17  is a perspective view of a state in which the shutter unit of the toner container opens the toner outlet; 
           [0024]      FIGS. 18A to 18C  are schematic diagrams illustrating opening operation performed by the shutter unit in association with attachment operation of the toner container to a toner-container holder; 
           [0025]      FIG. 19  is a perspective view of the cap unit from which the shutter unit is removed; 
           [0026]      FIG. 20  is a perspective view of a first member of the cap unit; 
           [0027]      FIG. 21  is another perspective view of the first member of the cap unit; 
           [0028]      FIG. 22  is a perspective view of a second member of the cap unit; 
           [0029]      FIG. 23  is a perspective view of the shutter unit; 
           [0030]      FIG. 24  is another perspective view of the shutter unit; 
           [0031]      FIG. 25  is a cross-sectional view of the vicinity of the cap unit of the toner container; 
           [0032]      FIG. 26  is a perspective view of the interior of the cap unit of the toner container; 
           [0033]      FIGS. 27A to 27D  are front views illustrating states in which different toner containers are inserted into insertion ports as viewed from the cap unit side; 
           [0034]      FIG. 28  is a perspective view of a bottle holder of the toner-container holder; 
           [0035]      FIG. 29  is a top view of the bottle holder of the toner-container holder; 
           [0036]      FIG. 30  is an enlarged perspective view of the vicinity of a leading-end portion of the bottle holder; 
           [0037]      FIG. 31  is another enlarged perspective view of the vicinity of the leading-end portion of the bottle holder; 
           [0038]      FIG. 32  is still another enlarged perspective view of the vicinity of the leading-end portion of the bottle holder; 
           [0039]      FIG. 33  is a perspective view of a cap holder of the toner-container holder; 
           [0040]      FIG. 34  is an enlarged perspective view of a part of the cap holder; 
           [0041]      FIG. 35  is another enlarged perspective view of a part of the cap holder; 
           [0042]      FIG. 36  is a perspective view of the interior of the cap holder; 
           [0043]      FIG. 37  is a cross-sectional view of the cap holder; 
           [0044]      FIG. 38  is a perspective view of how the toner container is set in the toner-container holder; 
           [0045]      FIG. 39  is a bottom view of how the shutter unit of the toner container opens the toner outlet while being engaged with a shutter holding mechanism of the toner-container holder; 
           [0046]      FIG. 40  is a bottom view illustrating a state following the state illustrated in  FIG. 39 ; 
           [0047]      FIG. 41  is a bottom view illustrating a state following the state illustrated in  FIG. 40 ; 
           [0048]      FIGS. 42A to 42D  are schematic diagrams illustrating procedures in which each portion of the cap holder is engaged with the cap unit when the attachment operation of the toner container proceeds; 
           [0049]      FIG. 43  is a schematic perspective view of the cap unit of the toner container and a seal member of the toner-container holder; 
           [0050]      FIGS. 44A to 44B  are schematic perspective views illustrating another configuration of the cap unit of the toner container and the seal member of the toner-container holder; 
           [0051]      FIG. 45  is an exploded view of a part of a toner container according to a second embodiment of the present invention; 
           [0052]      FIG. 46  is a perspective view of a head side of a container body of the toner container illustrated in  FIG. 45 ; 
           [0053]      FIG. 47  is a perspective view of a cap unit of the toner container of  FIG. 45 ; 
           [0054]      FIG. 48  is another perspective view of the cap unit of the toner container illustrated in  FIG. 45 ; 
           [0055]      FIG. 49  is a cross-sectional perspective view of the cap unit of the toner container of  FIG. 45 ; 
           [0056]      FIG. 50  is a cross-sectional view of the vicinity of the cap unit of the toner container illustrated in  FIG. 45 ; 
           [0057]      FIG. 51  is a perspective view of a state in which the shutter unit of the toner container of  FIG. 45  closes the toner outlet; 
           [0058]      FIG. 52  is a perspective view of a state in which the shutter unit of the toner container illustrated in  FIG. 45  opens the toner outlet; 
           [0059]      FIG. 53  is a perspective view of a stirring member of a toner container according to a third embodiment of the present invention; 
           [0060]      FIG. 54  is another perspective view of the stirring member illustrated in  FIG. 53 ; 
           [0061]      FIG. 55  illustrates three sides view of the stirring member illustrated in  FIG. 53 ; 
           [0062]      FIGS. 56A to 56D  are schematic front views of how the stirring member illustrated in  FIG. 53  rotates; 
           [0063]      FIGS. 57A to 57D  schematic front views of how the stirring member of the toner container illustrated in  FIG. 45  rotates; 
           [0064]      FIG. 58  is a schematic cross-sectional view of a cap unit of a toner container according to a fourth embodiment of the present invention; 
           [0065]      FIG. 59  is a perspective view of a flexible member disposed near a toner outlet of the toner container illustrated in  FIG. 57 ; 
           [0066]      FIGS. 60A to 60G  schematic front views of how a stirring member of the toner container illustrated in  FIG. 57  rotates; and 
           [0067]      FIG. 61  is a configuration diagram of a toner container having another configuration. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0068]    Exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, the same or equivalent components are denoted by the same reference letters or numerals, and explanation thereof will be appropriately simplified or omitted. 
       First Embodiment 
       [0069]    A first embodiment will be described in detail below with reference to  FIGS. 1 to 44 . The configuration and operation of whole of the image forming apparatus are described first. As illustrated in  FIG. 1 , four toner containers  32 Y,  32 M,  32 C, and  32 K corresponding to respective colors (yellow, magenta, cyan, and black) are detachably (in a replaceable manner) arranged in a toner-container holder  70  provided on the upper side of a body of an image forming apparatus  100  (also see  FIGS. 3 ,  4 , and  38 ). An intermediate transfer unit  15  is arranged below the toner-container holder  70 . Image forming units  6 Y,  6 M,  6 C, and  6 K corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in a line so as to face an intermediate transfer belt  8  of the intermediate transfer unit  15 . Toner supply devices  60 Y,  60 M,  60 C, and  60 K are arranged below the toner containers  32 Y,  32 M,  32 C, and  32 K, respectively. The toner supply devices  60 Y,  60 M,  60 C, and  60 K supply (feed) toner contained in the toner containers  32 Y,  32 M,  32 C, and  32 K to developing devices in the image forming units  6 Y,  6 M,  6 C, and  6 K, respectively. 
         [0070]    Referring to  FIG. 2 , the image forming unit  6 Y for yellow includes a photosensitive drum  1 Y, and also includes a charging unit  4 Y, a developing device  5 Y (a developing unit), a cleaning unit  2 Y, and a neutralizing unit (not illustrated), which are arranged around the photosensitive drum  1 Y. Image forming processes (charging process, exposing process, developing process, transfer process, and cleaning process) are preformed on the photosensitive drum  1 Y, on which a yellow image is formed. 
         [0071]    The other three image forming units  6 M,  6 C, and  6 K have almost the same configurations as the image forming unit  6 Y for yellow except that colors of toners to be used are different and images corresponding to the respective toner colors are formed. In the followings, explanation of the other three image forming units  6 M,  6 C, and  6 K will be appropriately omitted, and explanation of only the image forming unit  6 Y for yellow will be given. 
         [0072]    Referring to  FIG. 2 , the photosensitive drum  1 Y is rotated clockwise in a plane of  FIG. 2  by a drive motor (not illustrated). The surface of the photosensitive drum  1 Y is uniformly charged at the position of the charging unit  4 Y (charging process). The surface of the photosensitive drum  1 Y then reaches a position of radiating a laser light L emitted from an exposing device  7  (see  FIG. 1 ), where an exposing light is scanned to form an electrostatic latent image for yellow (exposing process). 
         [0073]    The surface of the photosensitive drum  1 Y then reaches a position of facing the developing device  5 Y, where the electrostatic latent image is developed and a yellow toner image is formed (developing process). The surface of the photosensitive drum  1 Y then reaches a position of facing the intermediate transfer belt  8  and a primary-transfer bias roller  9 Y, where the toner image on the photosensitive drum  1 Y is transferred to the intermediate transfer belt  8  (primary transfer process). At this time, a slight amount of non-transferred toner remains on the photosensitive drum  1 Y. 
         [0074]    The surface of the photosensitive drum  1 Y then reaches a position to face the cleaning unit  2 Y, where the non-transferred toner remaining on the photosensitive drum  1 Y is mechanically collected by a cleaning blade  2   a  (cleaning process). The surface of the photosensitive drum  1 Y finally reaches a position to face the neutralizing unit (not illustrated), where the residual potential on the photosensitive drum  1 Y is removed. In this manner, a series of the image forming professes performed on the photosensitive drum  1 Y is completed. 
         [0075]    The image forming processes are performed on the other image forming units  6 M,  6 C, and  6 K in the same manner as the yellow image forming unit  6 Y. Specifically, the exposing device  7  arranged below the image forming units emits a laser light L based on image information toward each photosensitive drum of the image forming units  6 M,  6 C, and  6 K. More specifically, the exposing device  7  emits the laser light L from a light source, and radiates the laser light L onto the photosensitive drum through a plurality of optical elements while scanning the laser light L by a polygon mirror being rotated. Subsequently, color toner images formed on the respective photosensitive drums through the developing process are superimposed and transferred onto the intermediate transfer belt  8 . In this manner, a color image is formed on the intermediate transfer belt  8 . 
         [0076]    Referring to  FIG. 1 , the intermediate transfer unit  15  includes the intermediate transfer belt  8 , four primary-transfer bias rollers  9 Y,  9 M,  9 C, and  9 K, a secondary-transfer backup roller  12 , a plurality of tension rollers, an intermediate-transfer cleaning unit, and the like. The intermediate transfer belt  8  is stretched and supported by a plurality of rollers, and is endlessly moved in a direction indicated by an arrow in  FIG. 1  in association with a rotation of the secondary-transfer backup roller  12 . 
         [0077]    The four primary-transfer bias rollers  9 Y,  9 M,  9 C, and  9 K sandwich the intermediate transfer belt  8  with the photosensitive drums  1 Y,  1 M,  1 C, and  1 K, respectively, to form primary transfer nips. A transfer bias with an opposite polarity to a polarity of toner is applied to the primary-transfer bias rollers  9 Y,  9 M,  9 C, and  9 K. The intermediate transfer belt  8  moves in the direction indicated by the arrow in  FIG. 1  and sequentially passes through the primary transfer nips of the primary-transfer bias rollers  9 Y,  9 M,  9 C, and  9 K. 
         [0078]    Accordingly, the toner images for respective colors on the photosensitive drums  1 Y,  1 M,  1 C, and  1 K are superimposed on the intermediate transfer belt  8  as primary transfers. 
         [0079]    The intermediate transfer belt  8  carrying the superimposed and transferred toner images of a plurality of colors reaches a position to face a secondary transfer roller  19 . At this position, the secondary-transfer backup roller  12  sandwiches the intermediate transfer belt  8  with the secondary transfer roller  19  to form a secondary transfer nip. The four-color toner image formed on the intermediate transfer belt  8  is transferred to a recording medium P, such as a transfer sheet, that has been conveyed to the position of the secondary transfer nip. At this time, non-transferred toner which has not been transferred to the recording medium P remains on the intermediate transfer belt  8 . 
         [0080]    The intermediate transfer belt  8  then reaches the position of the intermediate-transfer cleaning unit (not illustrated), where the non-transferred toner on the intermediate transfer belt  8  is collected. In this manner, a series of the transfer process performed on the intermediate transfer belt  8  is completed. 
         [0081]    The recording medium P is conveyed to the position of the secondary transfer nip from a feed unit  26 , which is disposed on the lower side of the body of the image forming apparatus  100 , via a feed roller  27  and a registration roller pair  28 . More specifically, a plurality of recording media P, such as transfer sheets, is stacked in the feed unit  26 . When the feed roller  27 , as drawn in  FIG. 1 , is rotated counterclockwise, the topmost recording medium P is fed to a nip between rollers of the registration roller pair  28 . 
         [0082]    The recording medium P conveyed to the registration roller pair  28  temporarily stops at the position of the nip between the rollers, which are stopped of driven rotation, of the registration roller pair  28 . The registration roller pair  28  is rotated in association with the color image on the intermediate transfer belt  8 , and the recording medium P is conveyed toward the secondary transfer nip. Then, a desired color image is transferred to the recording medium P. 
         [0083]    The recording medium P to which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of a fixing unit  20 , where the color image transferred to the surface of the recording medium P is fixed to the recording medium P by heat and pressure applied by a fixing belt and a pressing roller. The recording medium P is then discharged to the outside of the apparatus through a nip between rollers of a discharging roller pair  29 . The recording medium P discharged to the outside of the apparatus by the discharging roller pair  29  is sequentially stacked on a stack portion  30  as an output image. In this manner, a series of the image forming processes in the image forming apparatus is completed. 
         [0084]    The configuration and operation of the developing device in the image forming unit are described in detail below with reference to  FIG. 2 . The developing device  5 Y includes a developing roller  51 Y to face the photosensitive drum  1 Y, a doctor blade  52 Y to face the developing roller  51 Y, two conveyor screws  55 Y disposed in developer storage units  53 Y and  54 Y, and a density detection sensor  56 Y for detecting toner density in developer. The developing roller  51 Y includes a magnet fixed inside thereof and a sleeve that rotates around the magnet. Two-component developer G formed of carrier and toner is stored in the developer storage units  53 Y and  54 Y. The developer storage unit  54 Y communicates with a toner-falling conveying path  64 Y via an opening formed on an upper side of the developer storage unit  54 Y. 
         [0085]    The developing device  5 Y configured as above operates as follows. The sleeve of the developing roller  51 Y rotates in a direction indicated by an arrow in  FIG. 2 . The developer G, which is carried on the developing roller  51 Y by a magnetic field formed by the magnet, moves along the developing roller  51 Y in association with rotation of the sleeve. 
         [0086]    The developer G in the developing device  5 Y is controlled so that the proportion (toner density) of toner in the developer is in a predetermined range. More specifically, toner contained in the toner container  32 Y is supplied to the developer storage unit  54 Y via the toner supply device  60 Y (see  FIG. 3 ) according to toner consumption in the developing device  5 Y. The configuration and operation of the toner supply device will be described in detail below. 
         [0087]    The toner supplied to the developer storage unit  54 Y circulates in the two developer storage units  53 Y and  54 Y while being mixed and stirred together with the developer G (movement in a direction perpendicular to the sheet of  FIG. 2 ) by the two conveyor screws  55 Y. The toner in the developer G adheres to the carrier by triboelectric charging with the carrier, and is carried on the developing roller  51 Y together with the carrier due to the magnetic force formed on the developing roller  51 Y. 
         [0088]    The developer G carried on the developing roller  51 Y is conveyed in the direction indicated by the arrow in  FIG. 2  and reaches the position of the doctor blade  52 Y. After the amount is adjusted at this position, the developer G on the developing roller  51 Y is conveyed to the position (development area) to face the photosensitive drum  1 Y. The toner adheres to a latent image formed on the photosensitive drum  1 Y by an electric field formed in the development area. The developer G remaining on the developing roller  51 Y reaches the upper side of the developer storage unit  53 Y in association with the rotation of the sleeve, where the developer G is separated from the developing roller  51 Y. 
         [0089]    Referring to  FIGS. 3 and 4 , the toner supply devices  60 Y,  60 M,  60 C, and  60 K are described in detail below. Referring to  FIG. 3 , toner in the toner containers  32 Y,  32 M,  32 C, and  32 K arranged in the toner-container holder  70  of the body of the image forming apparatus  100  is appropriately supplied to the respective developing devices by the toner supply devices  60 Y,  60 M,  60 C, and  60 K, which are arranged for the respective toner colors, according to toner consumption in the developing devices for the respective colors. The four toner supply devices  60 Y,  60 M,  60 C, and  60 K have almost the same configurations and the four toner containers  32 Y,  32 M,  32 C, and  32 K have almost the same configurations, except that colors of toners used for the image forming processes are different from each other. Therefore, explanation will be given only of the toner supply device  60 Y and the toner container  32 Y for yellow, and explanation of the toner supply devices  60 M,  60 C, and  60 K and the toner containers  32 M,  32 C, and  32 K for the other three colors will be omitted appropriately. 
         [0090]    As illustrated in  FIG. 4 , when the toner containers  32 Y,  32 M,  32 C, and  32 K are attached to the toner-container holder  70  of the body of the image forming apparatus  100  (movement in a direction indicated by an arrow Q), a shutter unit  34   d  of each of the toner containers  32 Y,  32 M,  32 C, and  32 K moves in association with the attachment operation. Accordingly, a toner outlet W is opened and a toner supply port  73   w  of each of the toner supply devices  60 Y,  60 M,  60 C, and  60 K (see  FIGS. 3 and 38 ) and the toner outlet W operate together. Consequently, toner contained in the toner container  32 Y (same for  32 M,  32 C, and  32 K) is discharged from the toner outlet W and is accumulated in a toner tank  61 Y (same for  61 M,  61 C, and  61 K) through the toner supply ports  73   w  of the toner supply device  60 Y,  60 M,  60 C, and  60 K. 
         [0091]    Referring to a schematic diagram of  FIG. 3 , the toner container  32 Y is an approximately cylindrical toner bottle, and mainly includes a cap unit  34 Y that is held in a non-rotatable manner held by the toner-container holder  70  and a container body (bottle body)  33 Y that has an integrally-formed gear  33   c . The container body  33 Y is held so as to rotate relative to the cap unit  34 Y, and is driven by a driving unit  91  (which includes a drive motor, a driving gear  81 , and the like) to rotate in the direction indicated by an arrow in  FIG. 3 . In association with rotation of the container body  33 Y, toner contained in the toner container  32 Y (the container body  33 Y) is conveyed in a longitudinal direction (conveyed from left to right in  FIG. 3 ) by a spiral-shaped projection  33   b  formed on the inner circumferential surface of the container body  33 Y, and the toner is discharged from the toner outlet W of the cap unit  34 Y. That is, the driving unit  91  appropriately rotates the container body  33 Y of the toner container  32 Y, so that toner is appropriately supplied to the toner tank  61 Y. The toner containers  32 Y,  32 M,  32 C, and  32 K are replaced with new ones at the end of their lifetimes (when almost all of toner contained is consumed and the container becomes empty). 
         [0092]    Referring to  FIG. 3 , each of the toner supply devices  60 Y,  60 M,  60 C, and  60 K includes the toner-container holder  70 , the toner tank unit  61 Y, a toner conveyor screw  62 Y, a stirring member  65 Y, a toner end sensor  66 Y, and the driving unit  91 . The toner tank unit  61 Y is arranged below the toner outlet W of the toner container  32 Y for accumulating toner discharged from the toner outlet W of the toner container  32 Y. The bottom portion of the toner tank unit  61 Y is connected to an upstream portion of the toner conveyor screw  62 Y. The toner end sensor  66 Y for detecting that the amount of toner accumulated in the toner tank unit  61 Y becomes equal to or smaller than a predetermined amount is set on a wall surface of the toner tank unit  61 Y (at a position with a predetermined height from the bottom portion). A piezoelectric sensor or the like may be used as the toner end sensor  66 Y. When a control unit  90  detects, by using the toner end sensor  66 Y, that the amount of toner accumulated in the toner tank  61 Y becomes equal to or smaller than the predetermined amount (toner end detection), the control unit  90  controls the driving unit  91  (the driving gear  81 ) to rotate the container body  33 Y of the toner container  32 Y for a predetermined period of time so as to supply toner to the toner tank unit  61 Y. When the toner end detection by the toner end sensor  66 Y is not cancelled even after the above control is repeated, information for urging replacement of the toner container  32 Y is displayed on a display unit (not illustrated) of the body of the image forming apparatus  100  on the presumption that the toner container  32 Y is out of toner. 
         [0093]    The stirring member  65 Y that prevents toner accumulated in the toner tank unit  61 Y from being cohered is disposed at the center (near the toner end sensor  66 Y) of the toner tank unit  61 Y. The stirring member  65 Y has a flexible member arranged at a shaft portion thereof. The stirring member  65 Y rotates clockwise in  FIG. 3  so as to stir toner in the toner tank unit  61 Y. A tip of the flexible member of the stirring member  65 Y comes into slide contact with a detection surface of the toner end sensor  66 Y at every rotational period so as to prevent reduction in detection accuracy due to toner stuck to the detection surface of the toner end sensor  66 Y. 
         [0094]    The toner conveyor screw  62 Y conveys, though the details are not illustrated in the figure, toner accumulated in the toner tank unit  61 Y in an obliquely upper direction. Specifically, the toner conveyor screw  62 Y conveys toner from the bottom portion (a bottommost point) of the toner tank unit  61 Y toward an upper side of the developing device  5 Y straight. Toner conveyed by the toner conveyor screw  62 Y falls through the toner-falling conveying path  64 Y (see  FIG. 2 ) by falling due to own weight and is supplied to the developing device  5 Y (developer storage unit  54 Y). 
         [0095]    Referring to  FIG. 4 , the toner-container holder  70  mainly includes a cap holder  73  for holding the cap unit  34 Y of the toner container  32 Y, a bottle holder  72  (container-body holder) for holding the container body  33 Y of the toner container  32 Y, and an insertion port  71  serving as an insertion port in the attachment operation of the toner container  32 Y. The configuration of the toner-container holder  70  (the bottle holder  72  and the cap holder  73 ) will be described in detail later with reference to  FIGS. 28 to 42 . 
         [0096]    Referring to  FIG. 1 , when a body cover (not illustrated) arranged at a front side (a front side in a direction perpendicular to the sheet of  FIG. 1 ) of the body of the image forming apparatus  100  is opened, the toner-container holder  70  (the insertion port  71 ) is exposed. While each of the toner containers  32 Y,  32 M,  32 C, and  32 K is kept such that its longitudinal direction is horizontal, attachment/detachment operation of each of the toner containers  32 Y,  32 M,  32 C, and  32 K is performed from the front side of the body of the image forming apparatus  100  (the attachment/detachment operation using the longitudinal direction of the toner container as an attachment/detachment direction). 
         [0097]    The bottle holder  72  is formed such that the length thereof in the longitudinal direction is nearly equal to the length of the container body  33 Y in the longitudinal direction. The cap holder  73  is provided on one end of the bottle holder  72  in the longitudinal direction (attachment direction) while the insertion port  71  is provided on the other end of the bottle holder  72  in the longitudinal direction (attachment direction). Thus, along with the attachment operation of the toner container  32 Y, the cap unit  34 Y slides on the bottle holder  72  for a while after passing through the insertion port  71 , and thereafter is set to the cap holder  73 . 
         [0098]    In the first embodiment, an antenna  73   e  (radio-frequency identification (RFID) antenna) is mounted on the cap holder  73  of the toner-container holder  70  in which the toner containers  32 Y,  32 M,  32 C, and  32 K are detachably mounted in a line (see  FIGS. 34 and 35 ). More specifically, the antenna  73   e  is used for communicating with an RFID chip  35  (see  FIGS. 5 and 9 ) that is an electronic-information storage member mounted on an end face of the cap unit  34 Y of the toner container  32 Y. 
         [0099]    The RFID chip  35  (electronic-information storage member) of each of the toner containers  32 Y,  32 M,  32 C, and  32 K exchanges necessary information with the antenna  73   e  (RFID antenna) mounted on the body of the image forming apparatus  100 . Examples of the information exchanged between the RFID chip  35  and the antenna  73   e  include information on a manufacturing number of the toner container, the number of times the toner container has been recycled, information on the amount of toner that the toner container can contain, a lot number of the toner container, and toner color, and information on usage of the body of the image forming apparatus  100 . The above electronic information is stored in the RFID chip  35  (electronic-information storage member) in advance before the RFID chip  35  is mounted on the body of the image forming apparatus  100  (or information received from the body of the image forming apparatus  100  after the chip is mounted is stored). 
         [0100]    Referring to  FIGS. 5 to 26 , the toner containers  32 Y,  32 M,  32 C, and  32 K will be described in detail. As illustrated in  FIGS. 5 to 7 , the toner container  32 Y mainly includes the container body  33 Y (bottle body) and the cap unit  34 Y (bottle cap) arranged on the head of the container body. Referring to  FIG. 9 , the toner container  32 Y further includes, in addition to the container body  33 Y and the cap unit  34 Y, a stirring member  3 M; a cap seal  37 , the shutter unit  34   d , a shutter seal  36  as a seal member, and the RFID chip  35  as the electronic-information storage member. 
         [0101]    The gear  33   c , which rotates with the container body  33 Y together, and an opening A are arranged on one end of the container body  33 Y in the longitudinal direction (a direction perpendicular to the sheet of  FIG. 8 ) (see  FIG. 9 ). The opening A is provided on the head of the container body  33 Y (front end position in the attachment operation), and is used for discharging toner contained in the container body  33 Y into a space (a cavity B, see  FIG. 25 ) in the cap unit  34 Y. Toner is appropriately conveyed from the container body  33 Y to the cavity B in the cap unit  34 Y (conveyance is induced by the rotation of the container body  33 Y) to the extent that toner in the cap unit  34 Y does not fall below a predetermined draft line. 
         [0102]    The gear  33   c  is engaged with the driving gear  81  arranged in the toner-container holder  70  of the body of the image forming apparatus  100  to thereby rotate the container body  33 Y about an axis of the rotation. More specifically, the gear  33   c  is formed to circle around the circumference of the opening A, and includes a plurality of teeth that are radially arranged with respect to the axis of the rotation of the container body  33 Y. A part of the gear  33   c  is exposed through a notch portion  34   x  (see  FIG. 19 ) formed on the cap unit  34 Y, and is engaged with the driving gear  81  of the body of the image forming apparatus  100  at an engagement position on the lower left side of  FIG. 8 . Driving force is transmitted from the driving gear  81  to the gear  33   c , so that the container body  33 Y rotates clockwise in  FIG. 8 . In the first embodiment, the driving gear  81  and the gear  33   c  are realized as spur gears. 
         [0103]    Referring to  FIGS. 5 and 6 , a gripper  33   d  is arranged on the other end of the container body  33 Y in the longitudinal direction (a trailing end in the attachment direction) so that a user can grip the gripper  33   d  in attaching/detaching the toner container  32 Y. The user attaches the toner container  32 Y to the body of the image forming apparatus  100  by gripping the gripper  33   d  (movement of the toner container  32 Y in the direction indicated by an arrow in  FIG. 5 ). 
         [0104]    The spiral-shaped projection  33   b  is arranged on the inner circumferential surface of the container body  33 Y (a spiral-shaped groove when viewed from the outer circumferential surface side). The spiral-shaped projection  33   b  is used for discharging toner from the opening A in association with the rotation of the container body  33 Y in a predetermined direction. The container body  33 Y configured as above can be manufactured by blow molding with the gear  33   c  of the container body  33 Y, which is arranged on the circumferential surface, and the gripper  33   d  together. 
         [0105]    Referring to  FIGS. 9 and 10 , the toner container  32 Y according to the first embodiment includes the stirring member  33   f  that rotates together with the container body  33 Y and that is fitted to a bottle opening  33   a  (the opening A). The stirring member  33   f  is formed of a pair of rod-shaped members that extend from the cavity B in the cap unit  34 Y to inside of the container body  33 Y (also see  FIG. 25 ). Rotation of the stirring member  33   f  together with the opening A of the container body  33 Y improves the toner discharging performance from the opening A. 
         [0106]    Referring to  FIGS. 9 and 10 , engaging members (convex portions), which are engaged with claw members  34   j  (see  FIGS. 12 and 26 ) of the cap unit  34 Y in order to connect the container body  33 Y and the cap unit  34 Y to each other, are formed to circle around the outer circumference of the bottle opening  33   a  of the container body  33 Y. As described above, the container body  33 Y is engaged with the cap unit  34 Y in such a manner that the container body  33 Y is rotatable with respect to the cap unit  34 Y. Therefore, the gear  33   c  rotates relative to the cap unit  34 Y when the container body  33 Y rotates. 
         [0107]    The inner diameter of a head portion of the container body  33 Y (near the position where the gear  33   c  is formed) is smaller than the inner diameter of a toner-containing portion of the toner container (the position where the spiral-shaped projection  33   b  is formed) (also see  FIG. 25 ). The scooping portion (the portion surrounded by a dashed circle in  FIGS. 9 and 10 ), of which the inner circumferential surface protrudes inward, is provided on the head of the container body  33 Y. Toner conveyed toward the opening A by the spiral-shaped projection  33   b  in association with the rotation of the container body  33 Y is scooped, by the scooping portion (the portion surrounded by a dashed circle in  FIGS. 9 and 10 ), into a small-diameter portion of the head. The toner scooped into the small-diameter portion of the head is stirred by the stirring member  33   f , and is discharged to the cavity B of the cap unit  34 Y through the opening A. 
         [0108]    Referring to  FIGS. 11 to 14 , the shutter unit  34   d , the shutter seal  36  (seal member), the cap seal  37 , and the RFID chip  35  (electronic-information storage member) are arranged on the cap unit  34 Y of the toner container  32 Y. 
         [0109]    The cap unit  34 Y includes an insertion portion  34   z  with an inner diameter greater than the inner diameter of the cavity B (see  FIG. 26 ), and the opening A of the container body  33 Y is inserted into the insertion portion  34   z . Referring to  FIGS. 17 and 25 , the toner outlet W is formed at the bottom portion of the cap unit  34 Y to allow toner that has been discharged from the opening A of the container body  33 Y to be discharged to the outside of the toner container in a vertically downward direction (to fall by own weight). The shutter unit  34   d  for opening and closing the toner outlet W is held in a movable way by sliding at the bottom portion of the cap unit  34 Y. More specifically, the shutter unit  34   d  moves by a relative motion in the longitudinal direction from the cap unit  34 Y side to the container body  33 Y side (movement to the left in  FIG. 25 ) to open the toner outlet W, and the shutter unit  34   d  moves by a relative motion in the longitudinal direction from the container body  33 Y side to the cap unit  34 Y side (movement to the right in  FIG. 25 ) to close the toner outlet W. The open/close operation of the shutter unit  34   d  (the open/close operation of the toner outlet W) is performed in association with the attachment/detachment operation of the toner container  32 Y to the toner-container holder  70  (the body of the image forming apparatus  100 ) in the longitudinal direction. 
         [0110]      FIGS. 15 to 17  illustrate operation of the shutter unit  34   d  from start to completion of opening the toner outlet W.  FIG. 18  is a schematic diagram illustrating the opening operation of the shutter unit  34   d  (a deformable shutter member  34   d   2 ). 
         [0111]    Referring to  FIGS. 11 and 12 , a first hole  34   a  is formed at the upper portion (ceiling portion) of the cap unit  34 Y such that the first hole  34   a  extends in the longitudinal direction from the end face, which is perpendicular to the longitudinal direction, of the cap unit  34 Y. The first hole  34   a  functions as a main guide for positioning the cap unit  34 Y in the body of the image forming apparatus  100 . More specifically, the first hole  34   a  of the cap unit  34 Y is engaged with a main guide pin  73   a  (see  FIGS. 35 and 36 ) of the cap holder  73  in association with the attachment operation of the toner container  32 Y to the toner-container holder  70  in the longitudinal direction. 
         [0112]    A second hole unit  34   b  is formed at the lower portion (bottom portion) of the cap unit  34 Y such that the second hole unit  34   b  extends in the longitudinal direction from the end face, which is perpendicular to the longitudinal direction, of the cap unit  34 Y so as not to reach the position of the toner outlet W. The second hole unit  34   b  functions as a sub-guide for positioning the cap unit  34 Y in the body of the image forming apparatus  100 . More specifically, the second hole unit  34   b  of the cap unit  34 Y is engaged with a sub-guide pin  73   b  (see  FIGS. 35 and 36 ) of the cap holder  73  in association with the attachment operation of the toner container  32 Y to the toner-container holder  70  in the longitudinal direction. As illustrated in  FIG. 8 , a cross section of the second hole unit  34   b  is an ellipse of which a major axis is parallel to the vertical direction. 
         [0113]    With the use of the two holes  34   a  and  34   b  configured as above, the cap unit  34 Y is positioned in the toner-container holder  70 . Referring to  FIG. 8 , a virtual vertical line passing through the center of the first hole  34   a  and a virtual vertical line passing through the center of the second hole  34   b  are the same and identical straight line to pass through the center of the circle of the cap unit  34 Y when viewed in the plane perpendicular to the longitudinal direction. 
         [0114]    Referring to  FIG. 25 , the depth of the first hole  34   a  (or the length of the main guide pin  73   a  in the longitudinal direction) is greater than the depth of the second hole  34   b  (or the length of the sub-guide pin  73   b  in the longitudinal direction). Therefore, during the attachment operation of the toner container  32 Y to the toner-container holder  70  (the cap holder  73 ) in the longitudinal direction, engagement of the main guide pin  73   a  with the first hole  34   a  as the main positioning guide is started first, and thereafter, engagement of the sub-guide pin  73   b  with the second hole  34   b  as the sub-positioning guide is started. This allows the toner container  32 Y to be smoothly attached to the toner-container holder  70  (the cap holder  73 ). The first hole  34   a  that is long in the longitudinal direction is arranged on the ceiling portion of the cap unit  34 Y (a portion that is not buried in toner), so that toner conveying capability (flowability) in the cap unit  34 Y is not influenced by the first hole. Although the second hole  34   b  that is short in the longitudinal direction is arranged at the bottom portion of the cap unit  34 Y, the second hole  34   b  can be arranged by using a small space between the end face of the cap unit  34 Y and the position of the toner outlet W and can fully function as the sub-positioning guide. 
         [0115]    Referring to  FIGS. 11 to 14 , a first engaging portion  34   e  and a second engaging portions  34   f , which function as regulators for regulating the posture of the cap unit  34 Y in the horizontal direction perpendicular to the longitudinal direction in the cap holder  73  of the body of the image forming apparatus  100 , are formed on the ceiling portion of the cap unit  34 Y. The first engaging portion  34   e  and the second engaging portions  34   f  protrude upward in the vertical direction from the outer circumferential surface of the cap unit  34 Y and are line-symmetric with respect to a virtual vertical line passing through the center of the first hole  34   a  when viewed in the cross section perpendicular to the longitudinal direction (a cross section parallel to the front view of  FIG. 8 ), and the first engaging portion  34   e  and the second engaging portions  34   f  extend in the longitudinal direction (a direction perpendicular to the sheet of  FIG. 8 ). The first engaging portion  34   e  and the second engaging portions  34   f  are engaged with an engaged portion  73   m  (convex portion) of the cap holder  73  illustrated in  FIG. 34 . Therefore, the cap unit  34 Y is attached to and detached from the cap holder  73  while the posture of the cap unit  34 Y in the horizontal direction is regulated, and also, the posture of the cap unit  34 Y in the horizontal direction is regulated during when the cap unit  34 Y is attached to the cap holder  73 . 
         [0116]    More specifically, the first engaging portion  34   e  (regulator) is formed just above the first hole unit  34   a , and has an approximately rectangular cross section when viewed in the cross section perpendicular to the longitudinal direction. The first engaging portion  34   e  includes a protrusion  34   e   1  that protrudes in the longitudinal direction (attachment direction) relative to the end face of the first hole unit  34   a . A tip of the protrusion  34   e   1  has a tapered shape as illustrated in  FIG. 11 . In contrast, the second engaging portions  34   f  (regulators) are formed on both sides of the first engaging portion  34   e  and sandwich the first engaging portion  34   e . Each of the second engaging portions  34   f  has an approximately L-shaped cross section when viewed in the cross sectional plane that is perpendicular to the longitudinal direction (i.e., in a cross section parallel to the front view of  FIG. 8 ). The first engaging portion  34   e  is engaged with the two engaged portions  73   m  formed on the cap holder  73  so as to be set between the engaged portions while the two second engaging portions  34   f  are engaged with the engaged portions  73   m  so as to sandwich the two engaged portions  73   m  entirely from outside. When the cap unit  34 Y is attached to the cap holder  73 , the tapered protrusion  34   e   1  of the first engaging portion  34   e  is engaged with the engaged portion  73   m  before the second engaging portions  34   f  are engaged with the engaged portion  73   m , so that the cap unit  34 Y can be smoothly attached to the cap holder  73 . 
         [0117]    Referring to  FIGS. 11 to 14  again, lateral projections  34   c , which function as a second regulator for regulating the posture of the cap unit  34 Y in the rotational direction in the body of the image forming apparatus  100  (the cap holder  73 ), are formed on both lateral sides of the cap unit  34 Y. The lateral projections  34   c  (the second regulator) on both sides protrude in the horizontal direction from the outer circumferential surface of the cap unit  34 Y such that both of the lateral projections  34   c  are arranged to be in a virtually drawn horizontal line that passes a midpoint of a virtual line segment connecting a hole center of the first hole  34   a  and a hole center of the second hole  34   b  when viewed on the cross section perpendicular to the longitudinal direction, and the lateral projections  34   c  extend in the longitudinal direction (a direction perpendicular to the sheet of  FIG. 8 ). The two lateral projections  34   c  (the second regulator) are engaged with lateral grooves  73   c  (groove portion) of the cap holder  73  illustrated in  FIG. 34 . Therefore, the cap unit  34 Y is attached to and detached from the cap holder  73  while the posture of the cap unit  34 Y in the rotational direction is regulated, and also, the posture of the cap unit  34 Y in the rotational direction is regulated during when the cap unit  34 Y is attached to the cap holder  73 . 
         [0118]    More specifically, each tip of the lateral projections  34   c  has a tapered shape in the longitudinal direction (attachment direction) as illustrated in  FIG. 11 . When the cap unit  34 Y is attached to the cap holder  73 , the first engaging portion  34   e  is engaged with the engaged portion  73   m  first, and thereafter the second engaging portions  34   f  are engaged with the engaged portions  73   m  and the two lateral projections  34   c  having tapered shapes are engaged with the lateral grooves  73   c , so that the cap unit  34 Y can be smoothly attached to the cap holder  73  while the posture of the cap unit  34 Y is securely regulated. 
         [0119]    Referring to  FIGS. 11 and 12 , the RFID chip  35 , which is an electronic-information storage member for storing various types of electronic information, is mounted on a mount portion  34   k  (surrounded by a convex portion) formed between the first hole  34   a  and the second hole  34   b  on the end face of the cap unit  34 Y. The RFID chip  35  is arranged so as to face the antenna  73   e  of the cap holder  73  at a predetermined distance when the cap unit  34 Y is attached to the toner-container holder  70  (the cap holder  73 ). The RFID chip  35  performs non-contact communication (radio communication) with the antenna  73   e  while the cap unit  34 Y is being held by the cap holder  73 . 
         [0120]    In the first embodiment, because the RFID chip  35  is fixed between the first hole  34   a  (main guide hole) and the second hole  34   b  (sub-guide hole), the position of the RFID chip  35  relative to the antenna  73   e  of the cap holder  73  can be fixed with high accuracy. Therefore, it is possible to prevent a communication fault due to positional deviation of the RFID chip  35  from the antenna  73   e  (RFID antenna). 
         [0121]    The protrusion  34   e   1  and projections  34   m  are arranged so as to protrude further toward the front face side (right side in  FIG. 25 ) than the convex portion (rib) formed on the circumference of the mount portion  34   k . Therefore, even when the toner container  32 Y is placed with the container body  33 Y side up and the cap unit  34 Y side down, it is possible to prevent the RFID chip  35  held in the mount portion  34   k  from coming into direct contact with a placement surface of the cap holder  73 , thereby preventing the RFID chip  35  from being damaged. 
         [0122]    Referring to  FIGS. 11 and 12 , convex portions  34   g  and  34   h  for ensuring the incompatibility of the toner container  32 Y with toner containers of other colors are formed on the outer circumferential surface of the cap unit  34 Y. The convex portions  34   g  and  34   h  are configured to be engaged with corresponding engagement members  71   g  and  71   h  (formed on the insertion port  71  of the toner-container holder  70 , see  FIGS. 27A to 27D ) when the attachment operation of the toner container  32 Y to the toner-container holder  70  is correctly performed (when the toner container  32 Y is attached to a correct position in the toner-container holder  70 ). 
         [0123]    Specifically, referring to  FIGS. 27A to 27D , the convex portions  34   g  and  34   h  are arranged at different positions depending on each color of toner contained in the toner container (container body). The convex portions  34   g  and  34   h  corresponding to the toner container for cyan are formed at the positions at which the convex portions  34   g  and  34   h  can be engaged with only the engagement members  71   g  and  71   h  for cyan in the toner-container holder  70  (the insertion port  71 C) (see  FIG. 27C ), the convex portions  34   g  and  34   h  corresponding to the toner container for magenta are formed at the positions at which the convex portions  34   g  and  34   h  can be engaged with only the engagement members  71   g  and  71   h  for magenta in the toner-container holder  70  (the insertion port  71 M) (see  FIG. 27B ), the convex portions  34   g  and  34   h  corresponding to the toner container for yellow are formed at the positions at which the convex portions  34   g  and  34   h  can be engaged with only the engagement members  71   g  and  71   h  for yellow in the toner-container holder  70  (the insertion port  71 Y) (see  FIG. 27A ), and the convex portions  34   g  and  34   h  corresponding to the toner container for black are formed at the positions at which the convex portions  34   g  and  34   h  can be engaged with only the engagement members  71   g  and  71   h  for black in the toner-container holder  70  (the insertion port  71 K) (see  FIG. 27D ). 
         [0124]    With the above configurations, it is possible to prevent a toner container for a certain color (for example, a toner container for yellow) from being set in a toner-container holder for a different color (for example, a toner-container holder for cyan), thereby preventing a failure to form a desired color image. That is, it is possible to prevent the toner container from being erroneously set in the toner-container holder. 
         [0125]    Some of the incompatible convex portions  34   g  and  34   h  are cut off depending on the type (color) of toner contained in the toner container in order to fulfill the incompatible function for each color. That is, necessary claw portions are cut off with a cutting tool, such as a nipper or a cutter, from the cap unit  34 Y having the incompatible convex portions  34   g  and  34   h  (eight claw members are formed on the left and right sides in total as illustrated in  FIG. 8 ), so that the incompatible convex portions  34   g  and  34   h  of various shapes can be formed (in the first embodiment, four types are formed as illustrated in  FIGS. 27A to 27D . 
         [0126]    With the above configuration, it is not necessary to manufacture the same number of molds as the number of types of the toner containers (cap units), and it is possible to form a plurality of types of incompatible cap units by using one mold. Therefore, it is possible to reduce the entire manufacturing costs for the plurality of types of the toner containers. 
         [0127]    In the first embodiment, the four types of incompatible cap units illustrated in  FIGS. 27A to 27D  are formed. However, it is possible to further form a plurality of types of incompatible cap units by cutting off necessary claw portions with various combinations thereof from the eight claw portions of the incompatible convex portions  34   g  and  34   h  (eight claw members are formed on the left and right sides in total). 
         [0128]    Referring to  FIG. 12 , the notch portion  34   x , at which a part of the gear  33   c  of the container body  33 Y is exposed, is formed on the outer circumferential surface of the cap unit  34 Y. While the toner container  32 Y is being attached to the toner-container holder  70 , the gear  33   c  exposed through the notch portion  34   x  of the cap unit  34 Y is engaged with the driving gear  81  (disposed at a position indicated by a dashed-dotted line in  FIG. 34 , though the details are not illustrated) arranged in the cap holder  73 , so that the driving gear  81  rotates the container body  33 Y with the gear  33   c  together. 
         [0129]    Referring to  FIGS. 13 and 14 , a shutter housing unit  34   n  (housing unit) is formed at the bottom portion of the cap unit  34 Y in order to house a part of the shutter unit  34   d  (the deformable shutter member  34   d   2 ) when the shutter unit  34   d  opens the toner outlet W. The shutter housing unit  34   n  is a space having an approximately rectangular parallelepiped shape bulging downward from the insertion portion  34   z . The shutter housing unit  34   n  (housing unit) houses the deformable shutter member  34   d   2  by maintaining a deformed state (state in which the deformable shutter member  34   d   2  is elastically deformed upward by using the connection position of a shutter main unit  34   d   1  as a base point). Note that shutter housing unit  34   n  which includes the contact portion  34   n   5  houses the deformable shutter member  34   d   2 , but according to an embodiment does not house the slidable shutter  34   d   1  Referring to  FIGS. 11 and 12 , shutter rails  34   t  (see  FIG. 19 ) and slide grooves  34   n   1 , which function as a rail unit for guiding the open/close operation of the shutter unit  34   d , are formed on the inner surface of the shutter housing unit  34   n . The configuration and operation of the shutter unit  34   d  will be described in detail below. 
         [0130]    Referring to  FIG. 12 , a pressing rail  34   n   2  is formed on one side of the outer circumferential surface of the shutter housing unit  34   n . The pressing rail  34   n   2  is engaged with a pressing member  72   c  of the bottle holder  72  (see  FIGS. 30 and 38 ) in order to fix the position of the cap unit  34 Y passing through the bottle holder  72  when the toner container  32 Y is attached to/detached from the toner-container holder  70 . The pressing rail  34   n   2  is formed as a concave shape (a groove), and is arranged in parallel to the attachment direction (the longitudinal direction) of the toner container  32 Y. The pressing rail  34   n   2  is formed along the longitudinal direction (attachment/detachment direction) throughout the shutter housing unit  34   n . Both ends of the pressing rail  34   n   2  are kept open without providing wall portions. A tapered portion  34   n   21  is formed at the tip of the pressing rail  34   n   2  in the attachment direction for smooth engagement of the pressing member  72   c  with the pressing rail  34   n   2  in the attachment operation. 
         [0131]    Referring to  FIG. 11 , a pressure receiving face  34   n   3  is formed on the other side of the outer circumferential surface of the shutter housing unit  34   n . A pressure receiving member  72   d  of the bottle holder  72  (see  FIGS. 30 and 38 ) comes into slide contact with the pressure receiving face  34   n   3  in order to fix the position of the cap unit  34 Y that passes through the bottle holder  72  when the toner container  32 Y is attached to/detached from the toner-container holder  70 . 
         [0132]    With the above configuration, when the cap unit  34 Y is just before (or just after) being attached to (or detached from) the cap holder  73  in the attachment (or detachment) operation of the toner container  32 Y to (or from) the toner-container holder  70 , in the cap unit  34 Y, the pressing rail  34   n   2  is engaged with and urged by the pressing member  72   c  that is urged by a compression spring  72   e , so that the pressure receiving face  34   n   3  receives the urging force while coming into slide contact with the pressure receiving member  72   d . In this manner, the posture of the cap unit  34 Y just before (or just after) being attached to (or detached from) the cap holder  73  is regulated when passing through the bottle holder  72 . 
         [0133]    The cap unit  34 Y configured as above is connected with the container body  33 Y via the opening A, and discharges toner discharged from the opening A from the toner outlet W (the movement in the direction indicated by the dashed arrow in  FIG. 3 ). 
         [0134]    In the first embodiment, referring to  FIG. 25 , the cavity B (space) in an approximately cylindrical shape is formed inside the cap unit  34 Y such that the cavity B extends in the longitudinal direction (a horizontal direction in  FIG. 25 ). The inner diameter of the cavity B is smaller than the inner diameter of the insertion portion  34   z  illustrated in  FIG. 26  (a portion into which the head of the container body  33 Y is inserted). A toner fall path C, which has a columnar shape with a constant flow passage area (cross-sectional area of the flow passage) from a lower circumferential surface of the approximately-cylindrical cavity B to the toner outlet W, is formed inside the cap unit  34 Y. Therefore, toner that has been discharged from the opening A of the container body  33 Y to the cavity B of the cap unit  34 Y falls through the columnar toner fall path C by own weight and are smoothly discharged from the toner outlet W to the outside (the toner tank unit  61 Y) of the container. 
         [0135]    Referring to  FIG. 19 , the cap unit  34 Y (the shutter unit  34   d  and the shutter seal  36  are removed and hence, not illustrated) is formed by welding a first member  34 Y 1  (see  FIGS. 20 and 21 ) and a second member  34 Y 2  (see  FIG. 22 ). More specifically, the lateral projections  34   c  and the bottom portion of the first member  34 Y 1  are fitted to notch portions  34 Y 2   b  and  34 Y 2   c  of the second member  34 Y 2 , and an inner circumferential surface  34 Y 2   a  of the second member  34 Y 2  is fitted to and bonded (welded) to a bonding portion  34 Y 1   a  of the first member  34 Y 1 . 
         [0136]    As illustrated in  FIGS. 20 and 21 , the ring-shaped cap seal  37  as a seal member is attached to an opposing surface of the first member  34 Y 1  (a surface to face the bottle opening  33   a  formed on the circumference of the opening A of the container body  33 Y). The cap seal  37  is used for sealing a gap between opposing surfaces of the container body  33 Y and the cap unit  34 Y at the circumference of the opening A, and is made of elastic material such as polyurethane foam (foamed resin material). 
         [0137]    As illustrated in  FIG. 20 , the mount portion  34   k  for mounting the RFID chip  35  is formed on the end face of the first member  34 Y 1 . The mount portion  34   k  is formed as a wall portion of which the circumference protrudes from the end face of the first member  34 Y 1 . Base portions  34   k   2  for fixing four corners of the approximately-rectangular RFID chip  35  are formed at four corners of the rectangular wall portion inside the mount portion  34   k . By placing the RFID chip  35  on the base portions  34   k   2 , an electronic device formed on the back face of the RFID chip  35  (a surface to face the first member  34 Y 1 ) does not come into contact with the first member  34 Y 1 . The RFID chip  35  is fixed to the mount portion  34   k  in such a manner that heat and pressure are applied to a part of the base portions  34   k   2  for fusing after the RFID chip  35  is placed on the base portions  34   k   2 , and the base portions  34   k   2  are cooled to be solidified and joined to the four corners of the RFID chip  35 . 
         [0138]    As illustrated in  FIGS. 20 and 21 , the shutter rails  34   t  (rail unit) for guiding the shutter unit  34   d  to move in the longitudinal direction so as to open and close the toner outlet W is formed on both sides of the bottom portion of the first member  34 Y 1  (the cap unit  34 Y). The shutter rails  34   t  are formed on two vertical surfaces  34   s  that stand upward from both side edges of the bottom surface on which the toner outlet W is formed. In other words, the shutter rails  34   t  are formed by using a part of the vertical surfaces  34   s . The shutter rails  34   t  are formed by using upper surfaces of projections provided in a protruding manner at the both edges of the bottom surface (both edges in a direction perpendicular to the sheet of  FIG. 25 ). The vertical surfaces  34   s  that stand upward are formed on the side edge portions of the projections. The two vertical surfaces  34   s  formed on both side edges of the first member  34 Y 1  extend from the end of the shutter unit  34   d , which is at a position of closing the toner outlet W in the closing direction, to the protruding position in the longitudinal direction (attachment direction) (also see  FIG. 39 ). 
         [0139]    More specifically, two projections  34   m  (hornlike members) projecting in the longitudinal direction (attachment direction) from the end face of the cap unit  34 Y perpendicular to the longitudinal direction are formed on the cap unit  34 Y. The two projections  34   m  are disposed so as to sandwich the second hole  34   b  near a bottom edge of the second hole  34   b . The two vertical surfaces  34   s  are configured to include respective vertical surfaces of the side edges of the two projections  34   m . That is, the vertical surfaces at the outer edges of the two projections  34   m  are formed to be on the same planes as the vertical surfaces  34   s  on which the shutter rails  34   t  are formed. 
         [0140]    The vertical surfaces  34   s  configured as above are held surfaces that are held by first holding members  73   d   1  of shutter closing mechanisms  73   d  (shutter holding mechanisms) of the cap holder  73  (the toner-container holder  70 ) (see  FIG. 41 ). That is, the posture of the shutter unit  34   d  of the cap unit  34 Y set in the cap holder  73  is fixed by the shutter closing mechanisms  73   d  that also function as the shutter holding mechanisms. 
         [0141]    Because the vertical surfaces  34   s  that function as the held surfaces are extended in the attachment direction (to the upper direction in  FIG. 41 ), when the toner container  32 Y is removed from the toner-container holder  70 , a timing at which the shutter closing mechanisms  73   d  (second holding members  73   d   2 ) release holding of the shutter unit  34   d  using the vertical surfaces  34   s  as references can be delayed as compared to a timing at which the shutter closing mechanisms  73   d  completely close the shutter unit  34   d . Therefore, it is possible to prevent the toner container  32 Y from being removed from the body of the image forming apparatus  100  before the shutter unit  34   d  completely closes the toner outlet W. In particular, because the tips of the two projections  34   m  in the longitudinal direction (attachment direction) are located to protrude relative to the end face of the first hole  34   a  in the longitudinal direction (attachment direction), the shutter closing mechanisms  73   d  (the second holding units  73   d   2 ) release holding of the shutter unit  34   d  at the end of removal of the cap unit  34 Y from the cap holder  73 . Therefore, it is possible to securely prevent a closing error of the shutter unit  34   d . The configuration and operation of the shutter closing mechanisms  73   d  (the shutter holding mechanisms) will be described in detail below with reference to  FIGS. 39 to 41 . 
         [0142]    The shutter unit  34   d  with the shutter seal  36  (seal member) attached on a surface to face the toner outlet W is disposed at the bottom portion of the cap unit  34 Y configured as above. As illustrated in  FIGS. 15 to 17 , the shutter unit  34   d  opens and closes the toner outlet B in association with the attachment/detachment operation of the toner container  32 Y to the toner-container holder  70 . 
         [0143]    More specifically, referring to  FIGS. 23 and 24 , the shutter unit  34   d  includes a plate-shaped shutter main unit  34   d   1  and the deformable shutter member  34   d   2 , protruding from the shutter main unit  34   d   1 , that is thinner than the shutter main unit  34   d   1  and elastic. Shutter sliders  34   d   12  being a pair are formed on both outer sides of the shutter main unit  34   d   1 , and shutter-rail engaging portions  34   d   15  being a pair are formed on both inner sides of the shutter main unit  34   d   1 . The shutter sliders  34   d   12  are projections that extend on side portions of the shutter main unit  34   d   1  and parallel to the insertion direction of the toner container  32 Y. The shutter-rail engaging portions  34   d   15  project inside the shutter main unit  34   d   1  (on the side opposite to the side where the shutter sliders  34   d   12  protrude) by keeping a predetermined distance from the shutter seal  36 . The length of the shutter sliders  34   d   12  in the insertion direction of the toner container  32 Y is set, in a state in which the shutter sliders  34   d   12  are assembled to the toner container  32 Y, to be equal to the length between the end of one of the shutter rails  34   t  and one of convex portions  34   t   1  formed on the one of the shutter rails  34   t . The length of each of the slide grooves  34   n   1  formed in the shutter housing unit  34   n  in the insertion direction is approximately equal to the length of each of the shutter sliders  34   d   12 . 
         [0144]    The shutter sliders  34   d   12  of the shutter main unit  34   d   1  are engaged with the slide grooves  34   n   1  (rail units) of the cap unit  34 Y, and the shutter rails  34   t  (rail units) of the cap unit  34 Y are engaged, by being sandwiched, with the shutter-rail engaging portions  34   d   15  and the shutter seal  36  of the shutter main unit  34   d   1 . Therefore, the shutter main unit  34   d   1  opens and closes the toner outlet W by the movement of the shutter unit  34   d  along the rail units  34   n   1  and  34   t.    
         [0145]    The shutter seal  36  as a seal member is attached on the top face of the shutter main unit  34   d   1  (the surface to face the toner outlet W). The shutter seal  36  prevents toner from leaking between the shutter main unit  34   d   1  and the toner outlet W while the toner outlet W is being closed by the shutter main unit  34   d   1  (the shutter unit  34   d ). The shutter seal  36  is made of foamed resin material or the like. 
         [0146]    As illustrated in  FIGS. 23 and 24 , the shutter seal  36  of the first embodiment is disposed so as to protrude in the longitudinal direction (attachment direction) from one end of the shutter unit  34   d  along the closing direction. The tip of the shutter seal  36  (protruding portion) comes into contact with a wall formed on the circumference of the toner supply port  73   w  (see  FIG. 34 ) when the cap unit  34 Y is attached to the cap holder  73 , and functions as a seal member to prevent toner in the toner container  32 Y from leaking to the periphery of the toner supply port  73   w.    
         [0147]    Referring to  FIGS. 23 and 24 , the deformable shutter member  34   d   2  of the shutter unit  34   d  is integrally formed on the shutter main unit  34   d   1  and is elastically deformable in the vertical direction by using the connection position between the deformable shutter member  34   d   2  and the shutter main unit  34   d   1  as a base point (a portion surrounded by a dashed circle in  FIG. 18 ). The deformable shutter member  34   d   2  is disposed on the side of the container body  33 Y in the longitudinal direction when compared to the shutter main unit  34   d   1  (see  FIG. 15 ). Stoppers  34   d   22  and a stopper releasing unit  34   d   21  are formed on the deformable shutter member  34   d   2 . The shutter unit  34   d  is a mechanism for sealing the opening, the shutter main unit  34   d   1  is a cover, and the deformable shutter member  34   d   2  is an extension. This extension  34   d   2  includes a pushing surface  34   d   21  and a blocking surface  34   d   22 . There is a restriction  34   n   5  which contacts the blocking surface  34   d   22  to prevent the slidable shutter from sliding. The extension  34   d   2  along with the restriction  34   n   5  are an example of a means for restricting and permitting movement of the shutter. 
         [0148]    The stoppers  34   d   22  of the deformable shutter member  34   d   2  are walls formed on the endmost portions (tips of the deformable shutter member  34   d   2  on the distant side from the shutter main unit  34   d   1 ) in the opening direction of the deformable shutter member  34   d   2  (the left side in  FIG. 18 ). The stoppers  34   d   22  come into contact with contact portions  34   n   5  formed on the shutter housing unit  34   n  of the cap unit  34 Y, thereby regulating the motion of the shutter unit  34   d  in a direction from the toner outlet W being closed to open. That is, the stoppers  34   d   22  of the shutter unit  34   d  are in contact with the contact portions  34   n   5  while the toner container  32 Y remains isolated (when the toner container  32 Y is not set in the body of the image forming apparatus  100 ), so that the shutter unit  34   d  does not move by itself in the opening direction to open the toner outlet W. 
         [0149]    The stopper releasing unit  34   d   21  (stopper releasing projection) of the deformable shutter member  34   d   2  protrudes downward in the vertical direction. The stopper releasing unit  34   d   21  displaces the stoppers  34   d   22  upward along with upward elastic deformation of the deformable shutter member  34   d   2  upon receiving an external force from below, thereby releasing the state of contact between the stoppers  34   d   22  and the contact portions  34   n   5 . The stopper releasing unit  34   d   21  is formed between the stoppers  34   d   22  and the connection position (connection position between the shutter main unit  34   d   1  and the deformable shutter member  34   d   2 ), and is a ridge-shaped projection with slopes formed on both sides along the longitudinal direction. The stopper releasing unit  34   d   21  comes into contact with a stopper-release biasing portion  72   b  (see  FIGS. 28 and 38 ), which is formed on the bottle holder  72 , in association with the attachment operation of the toner container  32 Y to the toner-container holder  70 , and is pushed upward by the stopper-release biasing portion  72   b  (receives an external force from below). Then, the deformable shutter member  34   d   2  is elastically deformed upward and accordingly, the stoppers  34   d   22  are displaced upward. Thus, the contact state between the stoppers  34   d   22  and the contact portions  34   n   5  is released, so that the shutter unit  34   d  can move in the opening direction. 
         [0150]    Referring to  FIGS. 18A to 18C , the operation of the shutter unit  34   d  in association with the attachment operation of the toner container  32 Y to the toner-container holder  70  will be described in detail below. The positions of the shutter unit  34   d  in  FIGS. 18A to 18C  correspond, respectively, to the positions of the shutter unit  34   d  in  FIGS. 15 to 17 . 
         [0151]    As illustrated in  FIG. 18A , when the attachment operation of the toner container  32 Y to the toner-container holder  70  (movement to the right in  FIGS. 18A to 18C ) is started yet the stopper releasing unit  34   d   21  of the shutter unit  34   d  has not reached the position of the stopper-release biasing portion  72   b  formed on the bottle holder  72  (also see  FIGS. 28 and 38 ), the stoppers  34   d   22  of the shutter unit  34   d  are in contact with the contact portions  34   n   5  and the motion of the shutter unit  34   d  in the opening direction is regulated. As illustrated in  FIG. 18B , when the attachment operation of the toner container  32 Y proceeds, the stopper releasing unit  34   d   21  is pushed upward by the stopper-release biasing portion  72   b , and the deformable shutter member  34   d   2  is elastically deformed by using the connection position (a portion surrounded by a dashed circle) as a base point. Accordingly, the contact state between the stoppers  34   d   22  and the contact portions  34   n   5  is released and the shutter unit  34   d  is allowed to relatively move in the opening direction. 
         [0152]    Thereafter, the shutter unit  34   d  comes into contact with the wall formed on the circumference of the toner supply port  73   w  of the cap holder  73  (see  FIG. 34 ), so that the motion of the shutter unit  34   d  in the toner-container holder  70  (the cap holder  73 ) is regulated (the shutter unit  34   d  does not move in the longitudinal direction at all). However, the toner container  32 Y is allowed to move in the attachment direction, so that the shutter unit  34   d  relatively moves in the opening direction. That is, as illustrated in  FIG. 18C , the shutter unit  34   d  relatively moves to the side of the container body  33 Y and the deformable shutter member  34   d   2  is housed in the shutter housing unit  34   n  (housing unit). Thus, the opening process of the toner outlet W is completed by the movement of the shutter unit  34   d  in the opening direction. At this time, the stopper releasing unit  34   d   21  of the shutter unit  34   d  is stored in a notch portion  34   n   6  of the shutter housing unit  34   n  (also see  FIG. 17 ). 
         [0153]    As described above, the toner container  32 Y of the first embodiment includes, on the shutter unit  34   d , the deformable shutter member  34   d   2  that is elastically deformed by using the connection position of the shutter main unit  34   d   1  as a base point, and also includes, on the deformable shutter member  34   d   2 , the stoppers  34   d   22  for regulating the motion of the shutter unit  34   d  in the opening direction and the stopper releasing unit  34   d   21  for releasing the regulation. Therefore, the shutter unit  34   d  does not open the toner outlet W by itself while the toner container  32 Y remains isolated. Instead, the shutter unit  34   d  opens the toner outlet W in association with the attachment operation only when the toner container  32 Y is set in the body of the image forming apparatus  100 . 
         [0154]    The shutter-rail engaging portions  34   d   15  of the shutter main unit  34   d   1  (see  FIG. 23 ) also function as second stoppers that come into contact with a second contact portion formed on the cap unit  34 Y (a portion surrounded by a dashed circle in  FIGS. 19 and 20 ) and regulate a motion of the shutter unit  34   d  in a closing direction (the opposite direction of the direction in which the stoppers  34   d   22  perform regulation). That is, when the shutter unit  34   d  transits from the state in which the toner outlet W is open (the state illustrated in  FIG. 17 ) to the state in which the toner outlet W is closed (the state illustrated in  FIG. 15 ), the shutter-rail engaging portions  34   d   15  (the second stoppers) of the shutter unit  34   d  come into contact with the second contact portion (the portion surrounded by the dashed circle in  FIGS. 19 and 20 ) on the trailing side in the closing direction, and the stoppers  34   d   22  of the shutter unit  34   d  come into contact with the contact portions  34   n   5  on the leading side in the closing direction. Accordingly, the position of the shutter unit  34   d  in the closed state is fixed. At this time, the shutter-rail engaging portions  34   d   15  of the shutter unit  34   d  come into contact with the second contact portion just after passing over the convex portions  34   t   1  formed on the shutter rails  34   t  (see  FIGS. 20 and 21 ), so that it is possible to gain a click feeling in closing the shutter unit  34   d.    
         [0155]    Referring to  FIGS. 19 to 21 , ribs  34   p  having vertical surfaces on the same virtual planes as the vertical surfaces  34   s  of the shutter rails  34   t  (or vertical surfaces parallel to the virtual plane) are extended on the upper sides of the shutter rails  34   t  in the longitudinal direction while groove portions are interposed between the ribs  34   p  and the shutter rails  34   t . The ribs  34   p  prevent the first holding members  73   d   1  from entering the groove portions on the upper sides of the shutter rails  34   t  when the first holding members  73   d   1  of the shutter closing mechanisms  73   d  (shutter holding mechanisms) illustrated in  FIG. 41  hold the vertical surfaces  34   s  of the shutter rails  34   t . That is, a distance between one of the ribs  34   p  and one of the shutter rails  34   t  on the same side of the first member  34 Y 1  between the two elements of the ribs  34   p  and the shutter rails  34   t  (a distance of the groove portion) is set to be shorter than the heights of the first holding members  73   d   1  (the lengths in a direction perpendicular to the sheet of  FIG. 41 ). 
         [0156]    The ribs  34   p  can fulfill the functions as long as the ribs  34   p  laterally protrude (in the direction perpendicular to the sheet of  FIG. 25 ) and extend in the longitudinal direction (the horizontal direction in  FIG. 25 ). Therefore, the ribs  34   p  do not necessarily have the vertical surfaces described above. 
         [0157]    Referring to  FIGS. 23 and 24 , held portions or protrusions  34   d   11  being a pair are formed on the attachment direction&#39;s side of the tips on both sides of the edges of the shutter main unit  34   d   1  of the shutter unit  34   d . These held portions or protrusions may be considered a means for moving the shutter. As illustrated in  FIGS. 39 to 41 , the held portions  34   d   11  are held by the second holding members  73   d   2  of the shutter closing mechanisms  73   d  (shutter holding mechanisms) at the time of the open/close operation of the shutter unit  34   d . Each of the held portions  34   d   11  is formed of an engaging wall  34   d   11   a  that stands on the tip of the shutter main unit  34   d   1  in the attachment direction, a suppression wall  34   d   11   b  extending on the upper side of the held portion  34   d   11  to be parallel to the attachment direction, and a side wall  34   d   11   c  (which also functions as a side wall of the shutter main unit  34   d   1 ). 
         [0158]    The held portions  34   d   11  of the shutter unit  34   d  are held by the second holding members  73   d   2  of the shutter closing mechanisms  73   d  (shutter holding mechanisms) and the vertical surfaces  34   s  of the cap unit  34 Y are held by the first holding members  73   d   1  of the shutter closing mechanisms  73   d  (shutter holding mechanisms) at the time of the open/close operation of the shutter unit  34   d . Accordingly, the postures of the shutter unit  34   d  and the cap unit  34 Y in the cap holder  73  during the open/close operation of the shutter unit  34   d  can be fixed. At this time, the second holding members  73   d   2  of the shutter closing mechanisms  73   d  (shutter holding mechanisms) hold the side walls  34   d   11   c  of the held portions  34   d   11  (the shutter main unit  34   d   1 ), and the suppression walls  34   d   11   b  function to suppress vertical motion of the held portions  34   d   11  relative to the second holding members  73   d   2 . The engaging walls  34   d   11   a  of the held portions  34   d   11  are engaged with the second holding members  73   d   2 , which will be described later. The shutter closing mechanism  73  in its entirety, or just the second holding member  73   d   2  may be considered a movable catch. 
         [0159]    Referring to  FIGS. 17 and 41 , the toner outlet W of the cap unit  34 Y, which is opened and closed by the shutter unit  34   d  configured as above, has a hexagonal shape when viewed from below in the vertical direction. 
         [0160]    More specifically, an edge portion  34   r  protruding downward is formed on the circumference of the toner outlet W of the cap unit  34 Y. The edge portion  34   r  has vertex portions  34   r   1  on both sides in the longitudinal direction (the vertical direction in  FIG. 41 ). Each of the tips  34   r   1  has a pointed shape that is pointed in a longitudinal direction to be separated from the center of the toner outlet W. More specifically, when viewed from below in the vertical direction, the edge portion  34   r  is a hexagonal edge portion having parallel portions  34   r   2  that are opposed to each other along the longitudinal direction (the vertical direction in  FIG. 41 ), and the two vertex portions  34   r   1  that are positioned on the tips opposing to each other in the longitudinal direction. The toner outlet W has a hexagonal shape that follows the hexagonal shape of the edge portion  34   r.    
         [0161]    In this manner, the tips  34   r   1 , which are formed on the edge portion  34   r  on the circumference of the toner outlet W in the longitudinal direction (the direction in which the shutter unit  34   d  is opened and closed), have pointed shapes, so that when the shutter unit  34   d  is closed, the shutter seal  36  attached to the shutter unit  34   d  first comes into slide contact with the edge portion  34   r  at the pointed-shaped vertex portion  34   r   1  with a small area, and thereafter, the area of the slide contact gradually increases. Therefore, the shutter seal  36  is less likely to be peeled off or damaged due to the contact with the edge portion  34   r . When the shutter unit  34   d  is opened, the area of the slide contact gradually decreases, so that the damage on the shutter seal  36  due to the contact with the edge portion  34   r  is reduced. 
         [0162]    Referring to  FIG. 43 , a seal member  76  made of foamed resin material is attached to the circumference of the toner supply port  73   w  of the cap holder  73  (also see  FIG. 38 ), so that it is possible to prevent toner from scattering from the toner supply port  73   w  connected with the toner outlet W of the toner container  32 Y. Even when the edge portion  34   r  of the cap unit  34 Y comes into slide contact with the seal member  76  arranged on the circumference of the toner supply port  73   w  in association with the attachment operation of the toner container  32 Y in the longitudinal direction, the edge portion  34   r  comes into slide contact with the seal member  76  first at the pointed-shaped vertex portion  34   r   1  with a small area, and thereafter, the area of the slide contact gradually increases. Therefore, the seal member  76  of the toner supply port  73   w  is less likely to be peeled off or damaged due to the contact with the edge portion  34   r . In addition, when the detachment operation of the toner container  32 Y in the longitudinal direction is performed, the area of the slide contact between the seal member  76  of the toner supply port  73   w  and the edge portion  34   r  gradually decreases, so that damage on the seal member  76  of the toner supply port  73   w  due to the contact with the edge portion  34   r  can be reduced. In  FIG. 43 , the positional relationship between the seal member  76  of the toner supply port  73   w  and the toner outlet W is illustrated in a vertically reversed manner for the sake of easy understanding. 
         [0163]    Therefore, it is possible to securely prevent toner (or remaining toner) housed in the toner container  32 Y from scattering to outside in association with the attachment/detachment operation of the toner container  32 Y to/from the body of the image forming apparatus  100 . 
         [0164]    Referring to  FIG. 17 , in the first embodiment, the edge portion  34   r  of the cap unit  34 Y is configured such that planes (planes in contact with the vertex portions  34   r   1 ) perpendicular to the longitudinal direction (the vertical direction in  FIG. 41 ) have tapered shapes so that the amount of downward protrusion gradually decreases as the distance from the center of the toner outlet W increases. 
         [0165]    With this configuration, even when the shutter seal  36  attached to the shutter unit  34   d  is rubbed by the edge portion  34   r  in association with the attachment/detachment operation of the toner container  32 Y in the longitudinal direction, the shutter seal  36  is less likely to be damaged. Similarly, even when the seal member  76  (see  FIG. 43 ) arranged on the circumference of the toner supply port  73   w  of the cap holder  73  is rubbed by the edge portion  34   r  in association with the attachment/detachment operation of the toner container  32 Y in the longitudinal direction, the seal member  76  is less likely to be damaged. 
         [0000]    Denoting, respectively, the volume-average particle size and the number-average particle size of toner contained in the toner containers  32 Y,  32 M,  32 C, and  32 K by Dv (μm) and Dn (μm), the toner used in the first embodiment is manufactured so that the following conditions are satisfied. 
         [0000]      3≦ Dv≦ 8  (1)
 
         [0000]      1.00 ≦Dv/Dn≦ 1.40  (2)
 
         [0000]    Therefore, toner particles suited for an image pattern are selected in a developing process to maintain good image quality, and, even when the toner is stirred in the developing device for a long period of time, good developing capability can be maintained. Furthermore, toner can be efficiently and securely conveyed without blocking the toner supply path such as a tube  75 . 
         [0166]    The volume-average particle size and the number-average particle size of toner are measured by using, for example, Coulter-counter particle size distribution measurement device such as “COULTER COUNTER TA-2” (Beckman Coulter, Inc.) or “COULTER MULTISIZER 2” (Beckman Coulter, Inc.). 
         [0167]    In the first embodiment, as the toner contained in the toner containers  32 Y,  32 M,  32 C, and  32 K, approximately spherical toner with a shape factor SF-1 in a range from 100 to 180 and with a shape factor SF-2 in a range from 100 to 180 is used. Therefore, it is possible to maintain high transfer efficiency and prevent reduction in cleaning performance. In addition, toner can be efficiently and securely conveyed without blocking the toner supply path such as the tube  75 . 
         [0168]    The shape factor SF-1 represents the degree of sphericity of a toner particle, and is obtained by the following equation: 
         [0000]        SF -1=( M   2   /S )×(100π/4).
 
         [0169]    In the above equation, M is the maximum particle size in a projection plane of the toner particle (the largest particle size among various particle sizes), and S is an area of the projection plane of the toner particle. Therefore, a toner particle with the shape factor SF-1 of 100 is perfectly spherical, and the sphericity decreases as the shape factor becomes greater than 100. 
         [0170]    The shape factor SF-2 represents the irregularity of a toner particle, and is determined by the following equation: 
         [0000]        SF -2=( N   2   /S )×(100/4π).
 
         [0171]    In the equation, N is the circumferential length in the projection plane of the toner particle, and S is an area of the projection plane of the toner particle. Therefore, a toner particle with the shape factor SF-2 of 100 has no irregularities, and the irregularity increases as the shape factor becomes greater than 100. 
         [0172]    The shape factor SF-1 and the shape factor SF-2 are obtained by photographing toner particles by using a scanning electron microscope “S-800” (manufactured by Hitachi, Ltd.) and analyzing the obtained photograph of the toner particles by an image analyzer “LUSEX3” (manufactured by Nireco Corporation). 
         [0173]    The toner-container holder  70  (the bottle holder  72  and the cap holder  73 ) will be described in detail below with reference to  FIGS. 28 to 42 . 
         [0174]    As described above with reference to  FIG. 4 , the toner-container holder  70  includes the bottle holder  72 , the cap holder  73 , and the insertion port  71 . The toner container  32 Y is attached to the toner-container holder  70  from the insertion port  71  in the longitudinal direction as the attachment direction with the cap unit  34 Y positioned at the leading end of the container body  33 Y, while being kept by a user gripping the gripper  33   d  such that the longitudinal direction of the toner container  32 Y is parallel to the horizontal direction. The toner container  32 Y inserted from the insertion port  71  is pushed into the cap holder  73  by the user while sliding on the bottle holding face  72   a  of the bottle holder  72  (see  FIGS. 30 and 31 ). Referring to  FIGS. 28 and 29 , bottle holding faces  72   a Y,  72   a M,  72   a C, and  72   a K are formed on the bottle holder  72  for the respective colors, and the toner containers  32 Y,  32 M,  32 C, and  32 K are inserted to the respective bottle holding faces (in a direction indicated by an outlined arrow). Referring to  FIG. 33 , bottle holders  73 Y,  73 M,  73 C, and  73 K are formed on the cap holder  73  for the respective colors. The toner containers  32 Y,  32 M,  32 C, and  32 K are inserted in the respective bottle holders (in a direction indicated by an outlined arrow), so that each of the cap units  34 Y,  34 M,  34 C, and  34 K is non-rotatably held at the inserted position. 
         [0175]    Referring to  FIGS. 28 to 32 , the bottle holder  72  of the toner-container holder  70  includes the bottle holding face  72   a , the stopper-release biasing portion  72   b , the pressing member  72   c , the pressure receiving member  72   d , the compression spring  72   e , and a torsion coil spring  72   f.    
         [0176]    The bottle holding face  72   a  functions as a sliding face of the toner container  32 Y during the attachment/detachment operation of the toner container  32 Y, and functions as a holding unit of the rotatable container body  33 Y after setting of the toner container  32 Y is completed. 
         [0177]    Referring to  FIG. 29 , the stopper-release biasing portion  72   b  is a trapezoidal rib formed on the upper side (trailing side in the attachment direction of the toner container  32 Y) of the bottle holding face  72   a . As described above with reference to  FIG. 18 , the stopper-release biasing portion  72   b  pushes the stopper releasing unit  34   d   21  of the shutter unit  34   d  upward to release the contact state between the stoppers  34   d   22  and the contact portions  34   n   5  in association with the attachment operation of the toner container  32 Y (in order to enable the opening operation of the shutter unit  34   d ). 
         [0178]    Referring to  FIG. 29 , the pressing member  72   c  is disposed on a side wall on the right side of the bottle holding face  72   a  on the downstream side in the attachment direction of the toner container  32 Y. As illustrated in  FIGS. 30 and 32 , the tip of the pressing member  72   c  is formed to have a ridge shape, and the bottom portion of the pressing member  72   c  is connected to one end of the compression spring  72   e . The pressing member  72   c  configured as above is urged by the compression spring  72   e  to the left in  FIG. 29 . 
         [0179]    Referring to  FIG. 29 , on the other hand, the pressure receiving member  72   d  is disposed on a side wall on the left side of the bottle holding face  72   a  (the position to face the pressing member  72   c ) on the trailing side in the attachment direction of the toner container  32 Y. As illustrated in  FIG. 31 , the tip of the pressure receiving member  72   d  is formed such that two curves form a reversed V-shape (the v-shaped cleavage faces diagonally the lower right side in  FIG. 29 ), and the bottom portion of the pressure receiving member  72   d  is connected to the torsion coil spring  72   f . The pressure receiving member  72   d  is oscillatory movable about a shaft portion where the coil portion of the torsion coil spring  72   f  is inserted. 
         [0180]    With the pressing member  72   c  and the pressure receiving member  72   d  configured as above, the position of the cap unit  34 Y just before being inserted to the cap holder  73  is fixed when the toner container  32 Y is attached to the toner-container holder  70 . More specifically, the pressing rail  34   n   2  of the cap unit  34 Y (see  FIG. 12 ) is engaged with the pressing member  72   c , so that the cap unit  34 Y is pressed by the pressing member  72   c  to the left in  FIG. 29 . The pressure receiving face  34   n   3  (see  FIG. 11 ) of the cap unit  34 Y pressed by the pressing member  72   c  comes into slide contact with the pressure receiving member  72   d  by which the pressing force is received to fix the position of the cap unit  34 Y in the horizontal direction in  FIG. 29 . 
         [0181]    Referring to  FIGS. 33 to 37 , the cap holder  73  of the toner-container holder  70  includes the main guide pin  73   a , the sub-guide pin  73   b , the engaged portion  73   m , the lateral grooves  73   c , the shutter closing mechanisms  73   d  (the shutter holding mechanisms), the toner supply port  73   w , evacuation holes  73   k , the antenna  73   e  (RFID antenna), and the driving gear  81 . 
         [0182]    As described above with reference to  FIG. 11 , the main guide pin  73   a  and the sub-guide pin  73   b  are engaged with the first hole unit  34   a  and the second hole unit  34   b  of the cap unit  34 Y, respectively. Accordingly, the position of the cap unit  34 Y in the cap holder  73  is fixed. Referring to  FIG. 37 , the main guide pin  73   a  is longer than the sub-guide pin  73   b  in the longitudinal direction (positions of the guide surfaces that function as the base portions are formed on the plane that is common to the main guide pin  73   a  and the sub-guide pin  73   b ). The tip of the main guide pin  73   a  is formed to be tapered. Therefore, it is possible to smoothly attach the toner container  32 Y to the cap holder  73  in the attachment operation of the toner container  32 Y to the cap holder  73  in the longitudinal direction. 
         [0183]    The engaged portion  73   m  is engaged with the first engaging portion  34   e  and the second engaging portions  34   f  (regulator) formed on the cap unit  34 Y of the toner container  32 Y. Therefore, the cap unit  34 Y is attached to and detached from the cap holder  73  while the posture of the cap unit  34 Y in the horizontal direction is regulated. The lateral grooves  73   c  are engaged with the lateral projections  34   c  (second regulator) formed on the cap unit  34 Y of the toner container  32 Y. Therefore, the cap unit  34 Y is attached to and detached from the cap holder  73  while the posture of the cap unit  34 Y in the rotational direction is regulated. Furthermore, the posture of the cap unit  34 Y in the rotational direction is regulated while the cap unit  34 Y is being attached to the cap holder  73 . 
         [0184]    Referring to  FIGS. 34 and 38 , the shutter closing mechanisms  73   d  (shutter holding mechanisms) are disposed at the bottom position inside the cap holder  73 , and on the leading side of the toner supply port  73   w  in the attachment direction of the toner container  32 Y. The shutter closing mechanisms  73   d  being a pair are approximately horseshoe-shaped members that are arranged to face each other in the horizontal direction in  FIG. 39 , and are configured to be rotatable about supporting shafts  73   d   3  at which torsion coil springs are arranged. The first holding members  73   d   1  are formed on one end of the respective shutter closing mechanisms  73   d  (shutter holding mechanisms), and the second holding members  73   d   2  are formed on the other ends of the shutter closing mechanisms  73   d . As described above, the held portions  34   d   11  of the shutter unit  34   d  are held by the second holding members  73   d   2  and the vertical surfaces  34   s  of the cap unit  34 Y are held by the first holding members  73   d   1  during the open/close operation of the shutter unit  34   d  in the toner container  32 Y, so that the postures of the shutter unit  34   d  and the cap unit  34 Y in the cap holder  73  are fixed during the open/close operation of the shutter unit  34   d . Consequently, it is possible to smoothly perform the open/close operation. 
         [0000]      FIGS. 39 to 41  are diagrams illustrating the operation of the shutter closing mechanisms  73   d  (shutter holding mechanisms) in association with the open/close operation of the shutter unit  34   d . As illustrated in  FIG. 39 , when the opening operation of the shutter unit  34   d  is performed, the first holding members  73   d   1  come into contact with the projections  34   m  and the second holding members  73   d   2  come into contact with the held portions  34   d   11  of the shutter unit  34   d  in association with the attachment operation of the toner container  32 Y in the direction indicated by an outlined arrow. 
         [0185]    Thereafter, as illustrated in  FIG. 40 , when the attachment operation of the toner container  32 Y in the direction indicated by the outlined arrow proceeds, the shutter closing mechanisms  73   d  (shutter holding mechanisms) rotate about the supporting shafts  73   d   3 , so that the first holding members  73   d   1  hold the vertical surfaces  34   s  of the projections  34   m  of the cap unit  34 Y and the second holding members  73   d   2 , while being engaged with the engaging walls  34   d   11   a  of the held portions  34   d   11  of the shutter unit  34   d , hold the side walls  34   d   11   c  (the shutter unit  34   d ) of the shutter main unit  34   d   1  (the held portions  34   d   11 ). 
         [0186]    Thereafter, the shutter unit  34   d  comes into contact with the wall formed on the circumference of the toner supply port  73   w  of the cap holder  73  (see  FIG. 34 ). Accordingly, the motion of the shutter unit  34   d  in the cap holder  73  is regulated as the shutter unit  34   d  is sandwiched between the wall and the second holding members  73   d   2  (the shutter unit  34   d  never move in the longitudinal direction). However, because the movement of the toner container  32 Y in the attachment direction proceeds, the shutter unit  34   d  relatively moves in the opening direction. That is, as illustrated in  FIG. 41 , the shutter unit  34   d  relatively moves toward the container body  33 Y, thereby to open the toner outlet W. At this time, as illustrated in  FIG. 41 , the opening operation of the shutter unit  34   d  is performed while the first holding members  73   d   1  hold the vertical surfaces  34   s  of the cap unit  34 Y and the second holding members  73   d   2 , being engaged with the held portions  34   d   11  of the shutter unit  34   d , hold the shutter unit  34   d . Therefore, the postures of the shutter unit  34   d  and the cap unit  34 Y in the cap holder  73  are fixed and the opening operation of the shutter unit  34   d  can be smoothly performed. 
         [0187]    On the other hand, when the toner container  32 Y is removed (detached) from the toner-container holder  70  (the cap holder  73 ), the operation is performed in reverse order of the attachment operation described above. That is, the operation of the shutter closing mechanisms  73   d  (shutter holding mechanisms) in association with the closing operation of the shutter unit  34   d  is performed in the order of  FIGS. 41 ,  40 , and  39 . 
         [0188]    Referring to  FIG. 40 , in the first embodiment, because the vertical surfaces  34   s  that function as the held surfaces to be held by the first holding members  73   d   1  extend in the attachment direction (in the upward direction in  FIG. 40 ) (because the projections  34   m  are arranged), when the toner container  32 Y is removed from the toner-container holder  70 , a timing at which the shutter closing mechanisms  73   d  (the second holding members  73   d   2 ) release holding of the shutter unit  34   d  (the held portions  34   d   11 ) using the vertical surfaces  34   s  as references can be delayed as compared to a timing at which the shutter closing mechanisms  73   d  completely close the shutter unit  34   d . That is, because the vertical surfaces  34   s  (the projections  34   m ) are formed to extend to protrude to the upper side in  FIG. 40 , when the closing operation of the shutter unit  34   d  is performed (relative movement of the shutter unit  34   d  from the state illustrated in  FIG. 41  to the state illustrated in  FIG. 40 ), rotation of the shutter closing mechanisms  73   d  as illustrated in  FIG. 39  is prevented and the closing operation of the shutter unit  34   d  can be completed while the first holding members  73   d   1  are holding the vertical surfaces  34   s  of the projections  34   m  and the second holding members  73   d   2  are holding the held portions  34   d   11  of the shutter unit  34   d . In other words, when the vertical surfaces  34   s  are not formed to extend to protrude to the upper side in  FIG. 40 , the first holding members  73   d   1  release the holding of the vertical surfaces  34   s  at an earlier timing and the shutter closing mechanisms  73   d  instantly rotate as illustrated in  FIG. 39 , and accordingly, the second holding members  73   d   2  also release the holding of the held portions  34   d   11  of the shutter unit  34   d . Consequently, the shutter unit  34   d  cannot complete the closing operation. 
         [0189]    As described above, according to the first embodiment, because the projections  34   m  are arranged on the cap unit  34 Y, it is possible to prevent the toner container  32 Y from being removed from the body of the image forming apparatus  100  before the shutter unit  34   d  completely closes the toner outlet W. Referring to  FIGS. 34 and 35 , the cap holder  73  has the evacuation holes  73   k  formed on wall surfaces thereof such that the projections  34   m  of the cap unit  34 Y do not cause interference with the wall surface of the cap holder  73 . 
         [0190]    Referring to  FIGS. 42A to 42D , when the attachment operation of the toner container  32 Y to the toner-container holder  70  proceeds, each portion of the bottle holder  72  and the cap holder  73  is engaged with the cap unit  34 Y in sequence as described below. 
         [0191]    The cap unit  34 Y slides on the bottle holding face  72   a  in the horizontal direction to be inserted to the cap holder  73 . While sliding on the bottle holding face  72   a , the backlash of the cap unit  34 Y in the horizontal direction, which may occur immediately before being inserted to the cap holder  73 , is reduced by the pressing member  72   c  and the pressure receiving member  72   d . Thereafter, the first engaging portion  34   e  and the second engaging portions  34   f  of the cap unit  34 Y are engaged with the engaged portion  73   m  of the cap holder  73 , and the lateral projections  34   c  of the cap unit  34 Y are engaged with the lateral grooves  73   c  of the cap holder  73 , so that the posture of the cap unit  34 Y in the cap holder  73  is regulated in both the vertical and horizontal directions (the state illustrated in  FIG. 42A  proceeds to the state illustrated in  FIG. 42B ). Subsequently, the first hole unit  34   a  of the cap unit  34 Y is engaged with the main guide pin  73   a  of the cap holder  73 , so that the position of the main guide is fixed (the state illustrated in  FIG. 42C ). Thereafter, the second hole unit  34   b  of the cap unit  34 Y is engaged with the sub-guide pin  73   b  of the cap holder  73 , so that the positions of the main guide and sub-guide are fixed. Before the positioning is completed (until the engagement of the second hole unit  34   b  with the sub-guide pin  73   b  is completed), the stopper-release biasing portion  72   b  releases the contact state between the stoppers  34   d   22  of the shutter unit  34   d  and the contact portions  34   n   5  in the cap unit  34 Y. The shutter unit  34   d  starts the opening operation while the postures of the shutter unit  34   d  and the cap unit  34 Y in the cap holder  73  are fixed by the shutter closing mechanisms  73   d  (the shutter holding mechanisms) (the state illustrated in  FIG. 42C ). In addition, until the engagement of the second hole unit  34   b  with the sub guide pin  73   b  is completed, the seal member  76  arranged on the circumference of the toner supply port  73   w  of the cap holder  73  and the edge portion  34   r  (the wall portion) formed on the circumference of the toner outlet W of the cap unit  34 Y come into slide contact with each other. Accordingly, the toner outlet W that is opened in the cap unit  34 Y and the toner supply port  73   w  of the cap holder  73  are connected with each other to complete the setting of the cap unit  34 Y (the toner container  32 Y) in the cap holder  73  (the toner-container holder  70 ) (the state illustrated in  FIG. 42D ). At this time, the gear  33   c  of the container body  33 Y engages with the driving gear  81  of the image forming apparatus  100 , and the RFID chip  35  of the cap unit  34 Y is located at a position that is optimal to perform radio communication with the antenna  73   e  of the image forming apparatus  100 . 
         [0192]    In this manner, according to the first embodiment, because the postures of the shutter unit  34   d  and the cap unit  34 Y in the cap holder  73  are fixed by the shutter closing mechanisms  73   d  (the shutter holding mechanisms) in the attachment operation of the toner container  32 Y, it is possible to prevent the opening operation of the shutter unit  34   d  from being performed with the state in which the cap unit  34 Y (the shutter unit  34   d ) is tilted. 
         [0193]    In the attachment operation of the toner container  32 Y, after the first hole  34   a  of the cap unit  34 Y is engaged with the main guide pin  73   a  of the cap holder  73  to fix the position of the main guide, the postures of the shutter unit  34   d  and the cap unit  34 Y in the cap holder  73  are fixed by the shutter closing mechanisms  73   d  (the shutter holding mechanisms). Thereafter, the second hole  34   b  of the cap unit  34 Y is engaged with the sub-guide pin  73   b  of the cap holder  73  to fix the positions of the main guide and sub-guide. Therefore, the posture of the cap unit  34 Y (the shutter unit  34   d ) can be corrected before the positioning of the cap unit  34 Y to the sub-guide is completed. 
         [0194]    Before the positioning of the main guide is completed by the engagement of the first hole  34   a  of the cap unit  34 Y with the main guide pin  73   a  of the cap holder  73 , the lateral projections  34   c  of the cap unit  34 Y are engaged with the lateral grooves  73   c  of the cap holder  73 , for example, to regulate the posture of the cap unit  34 Y in the cap holder  73  in both the vertical and horizontal directions. Therefore, the cap unit  34 Y can be smoothly positioned to the cap holder  73 . 
         [0195]    After the postures of the shutter unit  34   d  and the cap unit  34 Y in the cap holder  73  are fixed by the shutter closing mechanisms  73   d  (the shutter holding mechanisms), the seal member  76  arranged on the circumference of the toner supply port  73   w  and the toner outlet W (the edge portion  34   r ) of the cap unit  34 Y come into slide contact with each other, and thereafter the second hole  34   b  of the cap unit  34 Y is engaged with the sub-guide pin  73   b  of the cap holder  73 , so that the positions of the main guide and sub-guide are fixed. Therefore, the posture of the cap unit  34 Y (the shutter unit  34   d ) can be corrected without receiving sliding contact resistance of the seal member  76 . 
         [0196]    In the first embodiment, because the shutter closing mechanism  73   d  (the shutter holding mechanism) is arranged near the sub-guide pin  73   b  and not near the main guide pin  73   a , the postures of the shutter unit  34   d  and the cap unit  34 Y in the cap holder  73  are easily corrected by the shutter closing mechanisms  73   d  (the shutter holding mechanisms). 
         [0197]    In the detachment of the toner container  32 Y, the first hole  34   a  of the cap unit  34 Y is kept engaged with the main guide pin  73   a  of the cap holder  73  until the closing operation of the shutter unit  34   d  is completed after the engagement of the second hole  34   b  of the cap unit  34 Y with the sub-guide pin  73   b  of the cap holder  73  is released. Therefore, it is possible to prevent the closing operation of the shutter unit  34   d  from being performed with the cap unit  34 Y (the shutter unit  34   d ) being tilted. 
         [0198]    As described above, according to the image forming apparatus of the first embodiment, by a user&#39;s single action of moving the toner container  32 Y in the longitudinal direction while gripping the gripper  33   d  (excluding the open/close operation of a body cover  110 ), the open/close operation of the toner outlet W by the shutter unit  34   d  is also performed and the attachment/detachment operation of the toner container  32 Y is completed. 
         [0199]    The toner container  32 Y of the first embodiment is disposed such that the toner outlet W with a relatively large opening area is arranged to be oriented downward in the vertical direction. Therefore, toner can efficiently be discharged directly from the toner outlet W by the toner&#39;s own weight. 
         [0200]    The attachment and detachment of the toner container  32 Y is performed from the front side of the toner-container holder  70  (the body of the image forming apparatus  100 ), not being performed from the upper side of the toner-container holder  70  (the body of the image forming apparatus  100 ). Therefore, flexibility in the layout of the upper side of the toner-container holder  70  is increased. For example, even when a scanner (a document read unit) is disposed above the toner supply devices, operability and workability are not deteriorated in the attachment and detachment of the toner container  32 Y. 
         [0201]    Furthermore, the toner container  32 Y is set in the body of the image forming apparatus  100  with the longitudinal direction of the toner container kept horizontal, and hence, it is possible to increase the toner capacity of the toner container  32 Y and to reduce the replacement frequency of the toner container  32 Y without affecting the layout of the entire body of the image forming apparatus  100  in the height direction. 
         [0202]    The characteristic configuration of the toner container  34 Y according to the first embodiment will be summarized with reference to  FIG. 43 . As illustrated in  FIG. 43 , the edge portion  34   r  (wall portion) formed on the circumference of the toner outlet W of the cap unit  32 Y has the vertex portions  34   r   1  on both the leading and trailing sides in the longitudinal direction. Each of the vertex portions  34   r   1  has a pointed shape. In addition, the edge portion  34   r  (especially the planes, other than the parallel portions  34   r   2 , that are in contact with the vertex portions  34   r   1 ) of the cap unit  34 Y is formed in a tapered shape inclined with respect to the vertical direction. With the above configuration, the shutter seal  36  of the shutter unit  34   d  and the seal member  76  provided on the circumference of the toner supply port  73   w  of the cap holder  73  smoothly come into slide contact with the edge portion  34   r  so as to gradually increase (or decrease) a contact area to the edge portion  34   r  in association with the attachment/detachment operation of the toner container  32 Y in the longitudinal direction. Therefore, the shutter seal  36  and the seal member  76  are less likely to be peeled or damaged. 
         [0203]    The shapes of the edge portion  34   r  and the toner outlet W are not limited to those in the first embodiment. For example, as illustrated in  FIG. 44A , the vertex portions  34   r   1  of the edge portion  34   r  can be formed in tapered shapes so that the amount of downward protrusion gradually decreases from the center of the toner outlet W. More specifically, tapered portions  34   r   3  inclined with respect to the vertical direction can be formed on the vertex portions  34   r   1  of the edge portion  34   r.    
         [0204]    Alternatively, as illustrated in  FIG. 44B , the toner outlet W can be formed in a rectangular shape while the outer circumference of the edge portion  34   r  is formed in the hexagonal shape. In addition, vertex portions  34   r   4  of the edge portion  34   r  can be formed in tapered shapes by being inclined with respect to the vertical direction. With both of the above configurations, similarly to the first embodiment, the shutter seal  36  of the shutter unit  34   d  and the seal member  76  provided on the circumference of the toner supply port  73   w  of the cap holder  73  smoothly come into slide contact with the edge portion  34   r  by gradually increasing (or decreasing) a contact area to the edge portion  34   r  in association with the attachment/detachment operation of the toner container  32 Y in the longitudinal direction. Therefore, the shutter seal  36  and the seal member  76  are less likely to be peeled or damaged. 
         [0205]    As described above, in the toner container  32 Y according to the first embodiment, the shutter seal  36  (seal member) is provided on the surface of the shutter unit  34   d  that faces the toner outlet W, and each of the vertex portions  34   r   1  of the edge portion  34   r  is formed in a pointed shape so that the edge portion  34   r  provided on the circumference of the toner outlet W of the cap unit  34 Y does not cause the shutter seal  36  to be peeled or damaged. Therefore, a space for arranging the toner container  32 Y can be effectively secured in the body of the image forming apparatus  100  and the toner container  32 Y can be set to the body of the image forming apparatus  100  with high fitting capability and operability, so that it is possible to prevent toner contained in the toner container  32 Y from scattering to the outside of the toner container  32 Y in association with attachment/detachment operation of the toner container  32 Y to the body of the image forming apparatus  100  even when the toner container  32 Y is configured to discharge toner from the toner outlet W by the toner&#39;s own weight. 
         [0206]    The toner container described above is a toner container that is detachably attached to a body of an image forming apparatus with a longitudinal direction of the toner container being kept horizontal. The toner container includes a cylindrical container body, a cap unit, and a shutter unit. The cylindrical container body has an opening on one end thereof in the longitudinal direction, and is configured to convey toner contained therein toward the opening that is inserted to the cap unit. The cap unit includes a toner outlet at a bottom portion thereof for discharging toner, which has been discharged from the opening of the container body, to the outside of the toner container in a vertically downward direction. The shutter unit is held at the bottom portion of the cap unit and moves along an outer periphery of the cap unit to thereby open and close the toner outlet. The shutter unit includes a seal member on a surface facing the toner outlet, and the cap unit includes an edge portion that protrudes downward and is provided on the circumference of the toner outlet. The edge portion of the cap unit has tips on both sides in the longitudinal direction. Each of the tips has a pointed shape that is pointed in the longitudinal direction so as to be separated from the center of the toner outlet. 
         [0207]    That is, the shutter unit  34   d  includes the shutter seal  36  (seal member) on the surface to face the toner outlet W. The cap unit  34 Y includes the edge portion  34   r  that protrudes downward and is formed on the circumference of the toner outlet W. The edge portion  34   r  has the vertex portions  34   r   1  on the leading and trailing sides in the longitudinal direction. Each of the vertex portions  34   r   1  has a pointed shape. 
         [0208]    In the toner container, when viewed from below in the vertical direction, the edge portion of the cap unit is a hexagonal edge portion having parallel portions that are opposed to each other along the longitudinal direction, and two vertex portions positioned on the tips opposing to each other in the longitudinal direction. 
         [0209]    In the toner container, the toner outlet is formed to be hexagonally shaped so as to follow the hexagonal shape of the edge portion when viewed from below in the vertical direction. 
         [0210]    In the toner container, the tips of the edge portion have tapered shapes so that the amount of downward protrusion gradually decreases according to the distance from the center of the toner outlet. 
         [0211]    In the toner container, the edge portion is formed so that the planes perpendicular to the longitudinal direction have tapered shapes and the amount of downward protrusion gradually decreases according to the distance from the center of the toner outlet. 
         [0212]    In the toner container, the seal member is disposed so as to protrude in the longitudinal direction from one end of the shutter unit in the closing direction. 
         [0213]    In the toner container, the cap unit includes a cylindrical cavity formed inside thereof so as to extend in the longitudinal direction and a toner fall path that has a columnar shape with a constant flow passage area from a lower circumferential surface of the cylindrical cavity to the toner outlet. 
         [0214]    In the toner container, the container body includes a spiral-shaped projection formed on inner circumferential surface thereof and is held to be rotatable with respect to the cap unit. 
         [0215]    The toner container is arranged in a body of an image forming apparatus. 
         [0216]    In this way, the seal member is provided on the surface of the shutter unit facing the toner outlet, and the tips of the edge portion have tapered shapes so that the edge portion provided on the circumference of the toner outlet does not cause the seal member to be peeled or damaged. Accordingly, a toner container and an image forming apparatus can be provided such that toner contained in the toner container is less likely to scatter to the outside of the toner container in attachment/detachment operation of the toner container to/from the body of the image forming apparatus. 
         [0217]    As described above, in the toner container  32 Y according to the first embodiment, because the vertical surfaces  34   s , on which the shutter rails  34   t  guiding the open/close operation of the shutter unit  34   d  are formed, extend from the end of the shutter unit  34   d , which is at a position of closing the toner outlet W in the closing direction, to the protruding position in the longitudinal direction, a timing at which the shutter closing mechanisms  73   d  arranged in the body of the image forming apparatus  100  release holding of the shutter unit  34   d  using the vertical surfaces  34   s  as references can be delayed as compared to a timing at which the shutter closing mechanisms  73   d  completely close the shutter unit  34   d . Therefore, a space for arranging the toner container  32 Y can be effectively secured in the body of the image forming apparatus  100  and the toner container  32 Y can be set to the body of the image forming apparatus  100  with high fitting capability and operability, so that it is possible to obviate troubles caused by the scatter of toner contained in the toner container  32 Y from to the outside of the toner container  32 Y in the detachment operation of the toner container  32 Y from the body of the image forming apparatus  100  even when the toner container  32 Y is configured to discharge toner from the toner outlet W by the toner&#39;s own weight. 
         [0218]    In a conventional toner container, when a flow passage area of a toner conveying path or an opening area of a toner outlet is increased, it is possible to configure a shutter unit so that the shutter unit can slide to open and close the toner outlet in association with attachment/detachment operation of the toner container to/from the body of an image forming apparatus, in order that attachment/detachment operation of the toner container to/from the apparatus body is accomplished by a single action when a longitudinal direction of the toner container is set as an attachment/detachment direction. In this case, however, it is necessary to configure the shutter unit closing the toner outlet so as not to easily move so that the toner contained in the toner container that is isolated from, and not arranged in, the body of the image forming apparatus does not leak toner to the outside of the toner container. 
         [0219]    The toner container described above is a toner container that is detachably attached to the body of an image forming apparatus with a longitudinal direction of the toner container kept horizontal, and includes: a cylindrical container body that has an opening on one end thereof in the longitudinal direction, and is configured to convey toner contained therein toward the opening; a cap unit into which the opening of the container body is inserted, and which includes a toner outlet at a bottom portion thereof for discharging toner, which has been discharged from the opening of the container body, to the outside of the toner container in a vertically downward direction; and a shutter unit that is held on the bottom portion of the cap unit, and moves along an outer periphery of the cap unit to thereby open and close the toner outlet. The shutter unit includes: a shutter main unit that is engaged with a rail unit arranged on the cap unit, and moves along the rail unit to thereby open and close the toner outlet; and a deformable shutter member that is integrally formed on the shutter main unit, and is elastically deformable in a vertical direction by using a connection position between the deformable shutter member and the shutter main unit as a base point. The deformable shutter member includes a stopper that comes into contact with a contact portion formed on the cap unit to thereby regulate a motion of the shutter unit in a direction to open the toner outlet that has been closed; and a stopper releasing unit that protrudes downward in the vertical direction, and displaces the stopper upward along with upward elastic deformation of the deformable shutter member upon receiving an external force from below to thereby release a contact state between the stopper and the contact portion. 
         [0220]    More specifically, the shutter unit  34   d  includes the deformable shutter member  34   d   2  that is formed to be elastically deformable by using a connection position, as a base point, between the deformable shutter member  34   d   2  and the shutter main unit  34   d   1  that moves along the rail unit of the cap unit  34 Y to open and close the toner outlet. The deformable shutter member  34   d   2  includes the stoppers  34   d   22  that regulate a motion of the shutter unit  34   d  in a direction to open the toner outlet that has been closed, and the stopper releasing unit  34   d   21  that releases a contact state between the stoppers  34   d   22  and the contact portions  34   n   5  upon receiving an external force from below. 
         [0221]    In the toner container described above, the shutter deformation unit is disposed on the side of the container body in the longitudinal direction with respect to the shutter main unit, the stopper is formed on the tip, which is away from the shutter main unit, of the deformable shutter member, and the stopper releasing unit is formed between the stopper and the connection position. 
         [0222]    In the toner container described above, the cap unit includes a housing unit that maintains a deformed state of the deformable shutter member when the shutter unit opens the toner outlet and houses the deformable shutter member. 
         [0223]    In the toner container described above, the shutter main unit further includes a second stopper that comes into contact with a second contact portion formed on the cap unit and regulates a motion of the shutter unit in a direction opposite to a direction in which the stopper performs regulation. 
         [0224]    In the toner container described above, the cap unit includes a cylindrical cavity formed inside thereof to extend in the longitudinal direction and a toner fall path that has a columnar shape with a constant flow passage area from a lower circumferential surface of the cylindrical cavity to the toner outlet. 
         [0225]    In the toner container described above, the container body includes a spiral-shaped projection formed on inner circumferential surface thereof and is held to be rotatable with respect to the cap unit. 
         [0226]    The toner container is arranged in the body of the image forming apparatus. 
         [0227]    In this way, according to the configuration, the shutter unit includes the deformable shutter member that elastically deforms by using the connection position between the shutter main unit and the deformable shutter member as a base point, and the deformable shutter member includes the stopper that regulates a motion of the shutter unit in the opening direction and the stopper releasing unit that releases the stopper. Accordingly, a toner container and an image forming apparatus can be provided in which the shutter unit that opens and closes the toner outlet is not easily moved when the toner container is isolated from the image forming apparatus. 
         [0228]    As described above, the toner container  32 Y of the first embodiment includes, on the shutter unit  34   d , the deformable shutter member  34   d   2  that is elastically deformed by using the connection position of the shutter main unit  34   d   1  as a base point, and also includes, on the deformable shutter member  34   d   2 , the stoppers  34   d   22  for regulating the motion of the shutter unit  34   d  in the opening direction and the stopper releasing unit  34   d   21  for releasing the regulation. Therefore, a space for arranging the toner container  32 Y can be effectively secured in the body of the image forming apparatus  100  and the toner container  32 Y can be set to the image forming body of the image forming apparatus  100  with high fitting capability and operability, so that it is possible to prevent the shutter unit  34   d  that opens and closes the toner outlet W from being easily moved when the toner container  32 Y is isolated even when the toner container  32 Y is configured to discharge toner from the toner outlet W by the toner&#39;s own weight. 
       Second Embodiment 
       [0229]    A second embodiment will be described in detail below with reference to  FIGS. 45 to 52 . A toner container according to the second embodiment is different from the first embodiment in that the stirring member  33   f  is differently configured. 
         [0230]    Referring to  FIG. 45 , the toner container  32 Y of the second embodiment mainly includes, similarly to the first embodiment, the container body  33 Y (bottle body) and the cap unit  34 Y (bottle cap) arranged at the head portion of the container body. The toner container  32 Y of the second embodiment further includes, in addition to the container body  33 Y and the cap unit  34 Y, the stirring member  33   f , the cap seal  37 , the shutter unit  34   d , the shutter seal  36  as a seal member, and the RFID chip  35  as an electronic-information storage member. 
         [0231]    Referring to  FIGS. 45 and 46 , in the toner container  32 Y of the second embodiment, similarly to the first embodiment, the stirring member  33   f  that rotates with the container body  33 Y is fitted to the bottle opening  33   a  (the opening A). 
         [0232]    The stirring member  33   f  is formed of a pair of plate members that extend from the cavity B in the cap unit  34 Y to the inside of the container body  33 Y (also see  FIG. 50 ). The stirring member  33   f  differs from that of the first embodiment in that the plate members in the pair are alternately tilted in the second embodiment. The stirring member  33   f  is configured such that the tip thereof reaches the upper side of the toner outlet W in the cap unit  34 Y and the other end thereof (the end on the opposite side) reaches the scooping portion (a portion surrounded by a dashed circle in  FIGS. 45 and 46 ) when the cap unit  34 Y and the container body  33 Y are assembled together. Rotation of the stirring member  33   f  in conjunction with the rotation of the opening A of the container body  33 Y improves the toner discharging performance from the opening A. In particular, the stirring member  33   f  according to the second embodiment improves toner stirring capability at front and back positions of the opening A because the pair of plate members are alternately tilted. 
         [0233]    Referring to  FIGS. 45 and 46 , engaging members (convex portions), which are engaged with claw members  34   j  (see  FIG. 50 ) of the cap unit  34 Y in order to connect the container body  33 Y with the cap unit  34 Y, are formed around an outer circumference of the bottle opening  33   a  of the container body  33 Y. As described above, the container body  33 Y (that has the integrally formed gear  33   c ) is engaged with the cap unit  34 Y so as to be relatively rotatable against the cap unit  34 Y. 
         [0234]    The inner diameter of a head portion of the container body  33 Y (near the position where the gear  33   c  is formed) is smaller than the inner diameter of a container portion containing toner (the position where the spiral-shaped projection  33   b  is formed) (see  FIG. 50 ). The scooping portion (the portion surrounded by the dashed circle in  FIGS. 45 and 46 ), of which inner circumferential surface protrudes inward, is provided on the head portion of the container body  33 Y. Toner conveyed toward the opening A by the spiral-shaped projection  33   b  in association with the rotation of the container body  33 Y is scooped, by the scooping portion (the portion surrounded by the dashed circle in  FIGS. 45 and 46 ), into a small-diameter portion of the head portion. The toner scooped into the small-diameter portion of the head portion is stirred by the stirring member  33   f , and is discharged to the cavity B of the cap unit  34 Y through the opening A. 
         [0235]    Referring to  FIGS. 47 to 50 , the shutter unit  34   d , the shutter seal  36 , the cap seal  37  (seal member), and the RFID chip  35  (electronic-information storage member) are arranged on the cap unit  34 Y of the toner container  32 Y. 
         [0236]    The cap unit  34 Y includes the insertion portion  34   z  with an inner diameter greater than the inner diameter of the cavity B (see  FIG. 49 ), and the opening A of the container body  33 Y is inserted into the insertion portion  34   z . Referring to  FIGS. 49 and 52 , the toner outlet W is formed at the bottom portion of the cap unit  34 Y to allow toner that has been discharged from the opening A of the container body  33 Y to be discharged to the outside of the toner container in a vertically downward direction (fall by own weight). The shutter unit  34   d  for opening and closing the toner outlet W is held in a slidable manner at the bottom portion of the cap unit  34 Y. More specifically, the shutter unit  34   d  relatively moves in the longitudinal direction from the cap unit  34 Y side to the container body  33 Y side (movement to the left in  FIG. 50 ) to open the toner outlet W. Furthermore, the shutter unit  34   d  relatively moves in the longitudinal direction from the container body  33 Y side to the cap unit  34 Y side (movement to the right in  FIG. 50 ) to close the toner outlet W. The open/close operation of the shutter unit  34   d  (the open/close operation of the toner outlet W) is performed in association with the attachment/detachment operation of the toner container  32 Y to the toner-container holder  70  (the body of the image forming apparatus  100 ) in the longitudinal direction.  FIGS. 51 and 52  illustrate operation of the shutter unit  34   d  from start to completion of opening the toner outlet W. 
         [0237]    Referring to  FIGS. 47 and 48 , the first hole  34   a  (main guide hole) is formed on the upper portion (ceiling portion) of the cap unit  34 Y such that the first hole  34   a  extends in the longitudinal direction from the end face of the cap unit  34 Y that is perpendicular to the longitudinal direction. The first hole  34   a  functions as a main guide for positioning the cap unit  34 Y in the body of the image forming apparatus  100 . More specifically, the first hole  34   a  of the cap unit  34 Y is engaged with the main guide pin  73   a  of the cap holder  73  in association with the attachment operation of the toner container  32 Y to the toner-container holder  70  in the longitudinal direction. 
         [0238]    The second hole  34   b  (sub-guide hole) is formed at the lower portion (bottom portion) of the cap unit  34 Y such that the second hole  34   b  extends in the longitudinal direction from the end face of the cap unit  34 Y that is perpendicular to the longitudinal direction so as not to reach the position of the toner outlet W. The second hole  34   b  functions as a sub-guide for positioning the cap unit  34 Y in the body of the image forming apparatus  100 . More specifically, the second hole  34   b  of the cap unit  34 Y is engaged with the sub-guide pin  73   b  of the cap holder  73  in association with the attachment operation of the toner container  32 Y to the toner-container holder  70  in the longitudinal direction. With the use of the two holes  34   a  and  34   b  thus configured, the position of the cap unit  34 Y is fixed in the toner-container holder  70 . 
         [0239]    Referring to  FIGS. 47 and 48 , shoulder portions  34   q  are formed on the outer circumference of a portion where the insertion portion  34   z  is formed and on both sides on the upper portion of the cap unit  34 Y. Each of the shoulder portions  34   q  has a flat top face and a flat lateral face that are approximately perpendicular to each other. 
         [0240]    When the toner container  32 Y is attached to the toner-container holder  70 , the shoulder portions  34   q  come into contact with positioning members (not illustrated), which are arranged on the cap holder  73  of the toner-container holder  70 , in association with the attachment operation. Accordingly, backlash of the cap unit  34 Y in the cap holder  73  can be suppressed, so that the cap unit  34 Y can be smoothly attached to the cap holder  73 . 
         [0241]    Referring to  FIGS. 47 and 48 , the lateral projections  34   c  (pressed portions) are arranged on both lateral sides of the cap unit  34 Y and protrude from the outer circumferential surface of the cap unit  34 Y. The lateral projections  34   c  according to the second embodiment are pressed in a direction against a force in the attachment direction (or the detachment direction) by pressing portions (not illustrated) of the cap holder  73  when the cap unit  34 Y is attached to (or detached from) the cap holder  73  of the toner-container holder  70  (the body of the image forming apparatus  100 ). Therefore, during the attachment operation (or the detachment operation) of the toner container  32 Y to the cap holder  73 , after a user feels a force against an operating force in the attachment direction (or the detachment direction) at the position where the lateral projections  34   c  are engaged with the pressing portions, the user increases the operating force in the attachment direction (or the detachment direction) to complete the attachment operation (or the detachment operation) instantly. Thus, the user gains a good click feeling in the attachment operation (or the detachment operation) of the toner container  32 Y to the cap holder  73 . 
         [0242]    More specifically, as illustrated in  FIGS. 47 and 48 , the lateral projections  34   c  according to the second embodiment are formed in ridge shapes along the longitudinal direction (attachment direction). The ridge shapes of the lateral projections  34   c  are formed such that the slopes on the tip side become more gentle than the slopes on the container body side. Therefore, the user can smoothly perform the attachment/detachment operation with a good click feeling when performing the attachment/detachment operation of the toner container  32 Y to the cap holder  73 . 
         [0243]    Referring to  FIGS. 47 and 48 , the convex portions  34   g  and  34   h  for ensuring the incompatibility of the toner container  32 Y with toner containers of other colors are formed on the outer circumferential surface of the cap unit  34 Y. The convex portions  34   g  and  34   h  are configured to engage with the lateral grooves  73   c  of the cap holder  73  when the attachment operation of the toner container  32 Y to the toner-container holder  70  is correctly performed (when the toner container  32 Y is attached to a correct position in the toner-container holder  70 ). With the above configuration, it is possible to prevent a toner container for a certain color (for example, a toner container for yellow) from being set in a toner-container holder for a different color (for example, a toner-container holder for cyan), thereby preventing a failure to form a desired color image. That is, it is possible to prevent the toner container from being erroneously set in the toner-container holder. 
         [0244]    Referring to  FIG. 48 , the convex portions  34   g  (incompatibly shaped portions) are two projections that are radially formed on the upper portion of the tip of the cap unit  34 Y. Each of the two projections (the incompatibly shaped portions  34   g ) includes a base portion  34   g   1  and two incompatible claw members  34   g   2  projecting from the base portion  34   g   1 . The base portion  34   g   1  has a trapezoidal shape that spreads out outward. The two incompatible claw members  34   g   2  are arranged so as to radially project outward from the top face of the base portion  34   g   1 . 
         [0245]    The incompatible claw members  34   g   2  are cut off depending on the type (color) of toner contained in the toner container so as to fulfill the incompatible function for each color. That is, some of the incompatible claw members  34   g   2  are cut off with a cutting tool, such as a nipper or a cutter, from the cap unit  34 Y having the four incompatible claw members  34   g   2  in total on the left and right sides, so that the incompatibly shaped portions  34   g  of various shapes can be formed. With the above configuration, it becomes unnecessary to manufacture the same number of molds as the number of types of the toner containers (cap units), and it becomes possible to form a plurality of types of incompatible cap units by using one mold to enable to reduce an entire manufacturing cost for producing the plurality of types of the toner containers. 
         [0246]    Referring to  FIG. 48 , a relatively large space is set between the two incompatible claw members  34   g   2  in the incompatibly shaped portions  34   g  so that the incompatible claw members  34   g   2  can be easily cut off by using a cutting tool such as a nipper or a cutter. 
         [0247]    Referring to  FIG. 48  and other related drawings such as  FIGS. 49 to 52 , the cap unit  34 Y of the second embodiment includes an incompatible convex portion  34   h  for identifying a destination of the toner container (for example, for domestic use or for export to North America, Europe, and other countries and regions). The convex portion  34   h  is configured to be engaged with an engagement member (not illustrated) formed in the bottle holder  72  when the body of the image forming apparatus  100  as a setting object is compatible (when the cap unit is set in the correct body of the image forming apparatus  100 ). 
         [0248]    In the toner container  32 Y according to the second embodiment, similarly to the first embodiment, the shutter seal  36  (seal member) is provided on the surface of the shutter unit  34   d  that faces the toner outlet W, and the vertex portions  34   r   1  of the edge portion  34   r  are formed in pointed shapes so that the edge portion  34   r  provided on the circumference of the toner outlet W of the cap unit  34 Y does not cause the shutter seal  36  to be peeled or damaged. 
         [0249]    Therefore, also in the second embodiment, similarly to the first embodiment, a space for arranging the toner container  32 Y can be effectively secured in the body of the image forming apparatus  100  and the toner container  32 Y can be set to the body of the image forming apparatus  100  with high fitting capability and operability, so that it is possible to prevent toner contained in the toner container  32 Y from scattering to the outside of the toner container  32 Y in association with the attachment/detachment operation of the toner container  32 Y to/from the body of the image forming apparatus  100  even when the toner container  32 Y is configured to discharge toner from the toner outlet W by the toner&#39;s own weight. 
         [0250]    Also in the toner container  32 Y according to the second embodiment, similarly to the first embodiment, because the vertical surfaces  34   s , on which the shutter rails  34   t  guiding the open/close operation of the shutter unit  34   d  are formed, extend from the end of the shutter unit  34   d , which is at a position of closing the toner outlet W in the closing direction, to the protruding position in the longitudinal direction, a timing at which the shutter closing mechanisms  73   d  arranged in the body of the image forming apparatus  100  release holding of the shutter unit  34   d  using the vertical surfaces  34   s  as references can be delayed in comparison to a timing at which the shutter closing mechanisms  73   d  completely close the shutter unit  34   d.    
         [0251]    Therefore, also in the second embodiment, similarly to the first embodiment, a space for arranging the toner container  32 Y can be effectively secured in the body of the image forming apparatus  100  and the toner container  32 Y can be set to the body of the image forming apparatus  100  with high fitting capability and operability, so that it is possible to prevent toner contained in the toner container  32 Y from scattering to the outside of the toner container  32 Y in association with detachment operation of the toner container  32 Y from the body of the image forming apparatus  100  even when the toner container  32 Y is configured to discharge toner from the toner outlet W by the toner&#39;s own weight. 
         [0252]    Also in the toner container  32 Y of the second embodiment, similarly to the first embodiment, the shutter unit  34   d  includes the deformable shutter member  34   d   2  that is elastically deformed by using the connection position of the shutter main unit  34   d   1  as a base point, and also includes, on the deformable shutter member  34   d   2 , the stoppers  34   d   22  for regulating the motion of the shutter unit  34   d  in the opening direction and the stopper releasing unit  34   d   21  for releasing the regulation. 
         [0253]    Therefore, also in the second embodiment, similarly to the first embodiment, a space for arranging the toner container  32 Y can be effectively secured in the body of the image forming apparatus  100  and the toner container  32 Y can be set to the body of the image forming apparatus  100  with high fitting capability and operability, so that it is possible to prevent the shutter unit  34   d  that opens and closes the toner outlet W from being easily moved when the toner container  32 Y remains isolated even when the toner container  32 Y is configured to discharge toner from the toner outlet W by the toner&#39;s own weight. 
       Third Embodiment 
       [0254]    A third embodiment will be described in detail below with reference to  FIGS. 53 to 56 . A toner container according to the third embodiment is different from the second embodiment in that the stirring member  33   f  is differently configured. 
         [0255]    The toner container  32 Y of the third embodiment mainly includes, similarly to the second embodiment, the container body  33 Y (bottle body) and the cap unit  34 Y (bottle cap) arranged on the head portion of the container body. The toner container  32 Y of the third embodiment further includes, in addition to the container body  33 Y and the cap unit  34 Y, the stirring member  33   f , the cap seal  37 , the shutter unit  34   d , the shutter seal  36  as a seal member, and the RFID chip  35  as an electronic-information storage member (see  FIG. 45 ). 
         [0256]    In the toner container  32 Y of the third embodiment, similarly to the second embodiment, the stirring member  33   f  that rotates in association with the container body  33 Y is fitted to the bottle opening  33   a  (the opening A). Specifically, referring to  FIGS. 53 to 55 , a fitting portion  33   f   2  of the stirring member  33   f  is press-fitted to the bottle opening  33   a  (the opening A) illustrated in  FIG. 45 . 
         [0257]    As illustrated in  FIGS. 53 to 55 , the stirring member  33   f  of the third embodiment includes plate members  33   f   1  being a pair, which extends from the cavity B in the cap unit  34 Y toward the inside of the container body  33 Y. The plate members  33   f   1  of the stirring member  33   f  are alternately tilted, similarly to the second embodiment. The stirring member  33   f  is configured such that the tip thereof (on the side where push plates  33   f   10  are formed) reaches the upper side of the toner outlet W in the cap unit  34 Y and the other end thereof (the end on the opposite side) reaches the scooping portion (the portion surrounded by the dashed circle in  FIGS. 45 and 46 ) when the cap unit  34 Y and the container body  33 Y are assembled together. Rotation of the stirring member  33   f  in conjunction with the rotation of the opening A of the container body  33 Y improves the toner discharging performance of the opening A. 
         [0258]    As illustrated in  FIGS. 53 to 55 , the stirring member  33   f  of the third embodiment is different from the second embodiment in that the push plates  33   f   10  are arranged on the tips of the plate members  33   f   1  (on the side toward the inside of the cap unit  34 Y). The push plates  33   f   10  are plate members that stand approximately perpendicular to the main bodies of the plate members  33   f   1 . Each of the push plates  33   f   10  includes a tapered portion  33   f   100  on the outer circumference thereof. 
         [0259]    As described above, because the push plates  33   f   10  are arranged on the tips of the plate members  33   f   1  of the stirring member  33   f , the push plates  33   f   10  push toner toward the toner outlet W in the cap unit  34 Y in association with the rotation of the stirring member  33   f . Therefore, even when the cap unit  34 Y is clogged with toner in the vicinity of the toner outlet W (the toner fall path C), the toner can be smoothly discharged from the toner outlet W. 
         [0260]      FIGS. 56A to 56D  are schematic front views of how the stirring member  33   f  rotates in the toner container  32 Y that has the stirring member  33   f  with the push plates  33   f   10  (the stirring member  33   f  of the third embodiment). On the other hand,  FIGS. 57A to 57D  are schematic front views of how the stirring member  33   f  rotates in the toner container  32 Y that has the stirring member  33   f  without the push plates  33   f   10  (the stirring member  33   f  of the second embodiment). 
         [0261]    In  FIGS. 56A and 57A , black arrows indicate a toner conveying direction in which the stirring member  33   f  conveys toner toward the toner outlet W (the toner supply port  73   w ). 
         [0262]    As illustrated in  FIG. 57A , when the push plates  33   f   10  are not arranged on the tips of the plate members  33   f   1  of the stirring member  33   f , the push plates  33   f   10  convey toner in a circumferential direction along the inner circumference of the cap unit  34 Y in association with the rotation of the stirring member  33   f . By contrast, as illustrated in  FIG. 56A , when the push plates  33   f   10  are arranged on the tips of the plate members  33   f   1  of the stirring member  33   f , the push plates  33   f   10  convey toner toward the toner outlet W (conveyance in an approximately normal direction with respect to the inner circumference of the cap unit  34 Y) in association with the rotation of the stirring member  33   f.    
         [0263]    In the toner container  32 Y according to the third embodiment, similarly to each of the above-described embodiments, the shutter seal  36  (seal member) is provided on the surface of the shutter unit  34   d  to face the toner outlet W, and the vertex portions  34   r   1  of the edge portion  34   r  are formed in pointed shapes so that the edge portion  34   r  provided on the circumference of the toner outlet W of the cap unit  34 Y does not cause the shutter seal  36  to be peeled or broken. 
         [0264]    Therefore, also in the third embodiment, similarly to each of the above-described embodiments, a space for arranging the toner container  32 Y can be effectively secured in the body of the image forming apparatus  100  and the toner container  32 Y can be set to the body of the image forming apparatus  100  with high fitting capability and operability, so that it is possible to prevent toner contained in the toner container  32 Y from scattering to the outside of the toner container  32 Y in association with attachment/detachment operation of the toner container  32 Y to the body of the image forming apparatus  100  even when the toner container  32 Y is configured to discharge toner from the toner outlet W by the toner&#39;s own weight. 
       Fourth Embodiment 
       [0265]    A fourth embodiment will be described in detail below with reference to  FIGS. 58 ,  59 , and  60 A to  60 G. A toner container according to the fourth embodiment is different from the third embodiment in that a flexible member  34   u  is disposed near the toner outlet W of the cap unit  34 Y. 
         [0266]    The toner container  32 Y of the fourth embodiment mainly includes, similarly to the third embodiment, the container body  33 Y (bottle body) and the cap unit  34 Y (bottle cap) arranged on the head portion of the container body. The toner container  32 Y of the fourth embodiment further includes, in addition to the container body  33 Y and the cap unit  34 Y, the stirring member  33   f , the cap seal  37 , the shutter unit  34   d , the shutter seal  36  as a seal member, and the RFID chip  35  as an electronic-information storage member (see  FIG. 45 ). 
         [0267]    In the toner container  32 Y of the fourth embodiment, similarly to the third embodiment, the stirring member  33   f  that rotates in conjunction with the container body  33 Y is fitted to the bottle opening  33   a  (the opening A). 
         [0000]    As illustrated in  FIG. 58 , the stirring member  33   f  of the fourth embodiment includes the plate members  33   f   1  being a pair, which extends from the cavity B in the cap unit  34 Y toward the inside of the container body  33 Y (which are alternately tilted). The stirring member  33   f  of the fourth embodiment further includes the push plates  33   f   10  on the tips of the plate members  33   f   1  (on the side toward the inside of the cap unit  34 Y), similarly to the third embodiment. 
         [0268]    Referring to  FIGS. 58 ,  59 , and  60 A to  60 G, the cap unit  34 Y of the fourth embodiment is different from the third embodiment in that the cap unit  34 Y includes a flexible member  34   u  made of flexible material such as mylar with a thickness of about 0.188 mm to 0.5 mm extending from the toner fall path C to the cavity B. More specifically, as illustrated in  FIG. 59 , a part of the flexible member  34   u  is bent, and a fixation portion  34   u   2  (with a width wider than a flexible portion  34   u   1 ) as an attachment surface is attached (fixed) to the inner wall of the toner fall path C (the inner wall on the side near the toner outlet W and on the downstream side of the stirring member  33   f  in the rotational direction). Specifically, the fixation portion  34   u   2  is attached to the inner wall of the toner fall path C so that the bent portion of the flexible member  34   u  can be located in the toner fall path C. The flexible portion  34   u   1  of the flexible member  34   u  is a free end and extends from the toner fall path C to the inside of the cavity B. The tip of the flexible portion  34   u   1  comes into contact with the push plates  33   f   10  in association with the rotation of the stirring member  33   f , so that even when the cap unit  34 Y is clogged with toner in the vicinity of the toner outlet W (the toner fall path C) is clogged with toner, the toner can be smoothly discharged from the toner outlet W. 
         [0269]    More specifically, as illustrated in  FIGS. 60A to 60D , the push plates  33   f   10  push the flexible member  34   u  (the flexible portion  34   u   1 ) in association with the rotation of the stirring member  33   f , so that the flexible member  34   u  is gradually bent in an arched shape. At this time, even when the portion between the inner wall of the toner fall path C and the flexible member  34   u  is clogged with toner with the stirring member  33   f  being in the state illustrated in  FIG. 60A , because the flexible member  34   u  is greatly bent in an arched shape and the space between the inner wall of the toner fall path C and the flexible member  34   u  increases as illustrated in  FIG. 60D , toner clogging the toner fall path C is loosened. 
         [0270]    Thereafter, as illustrated in  FIG. 60E , a planer portion of the push plate  33   f   10  and a planer portion of the flexible member  34   u  overlap each other, and the flexible member  34   u  is deformed to become nearly flat from the fixation portion  34   u   2  to the flexible portion  34   u   1 . During this deformation, the space between the flexible member  34   u  and the toner becomes large to promote the toner for further loosening and the toner is further supplied to the space by being pushed by the push plate  33   f   10  (the state illustrated in  FIG. 58 ). Accordingly, toner discharging efficiency and toner loosening performance at the toner outlet W (the toner fall path C) are promoted. Thereafter, as illustrated in  FIG. 60F , the flexible member  34   u  gets completely warped, and the contact between the flexible member  34   u  and the push plate  33   f   10  is released. Then, as illustrated in  FIG. 60G , the flexible member  34   u  is returned to the initial state by the elastic force of the flexible member  34   u . At this time, the toner receives a restoring force caused by the elasticity of the flexible member  34   u , so that the toner loosening and the toner discharging at the toner fall path C are promoted. 
         [0271]    The shape of the flexible member  34   u  is not limited to that described in the fourth embodiment. For example, the flexible member  34   u  may not have a bent portion, or may have the fixation portion  34   u   2  in a different shape. 
         [0272]    In the toner container  32 Y according to the fourth embodiment, similarly to each of the above-described embodiments, the shutter seal  36  (seal member) is provided on the surface of the shutter unit  34   d  that faces the toner outlet W, and the vertex portions  34   r   1  of the edge portion  34   r  are formed in pointed shapes so that the edge portion  34   r  provided on the circumference of the toner outlet W of the cap unit  34 Y does not cause the shutter seal  36  to be peeled or damaged. 
         [0273]    Therefore, also in the fourth embodiment, similarly to each of the above-described embodiments, a space for arranging the toner container  32 Y can be effectively secured in the body of the image forming apparatus  100  and the toner container  32 Y can be set to the body of the image forming apparatus  100  with high fitting capability and operability, so that it is possible to prevent toner contained in the toner container  32 Y from scattering to the outside of the toner container  32 Y in association with attachment/detachment operation of the toner container  32 Y to the body of the image forming apparatus  100  even when the toner container  32 Y is configured to discharge toner from the toner outlet W by the toner&#39;s own weight. 
         [0274]    In the above embodiments, only toner is contained in the toner containers  32 Y,  32 M,  32 C, and  32 K. However, it is possible to contain two-component developer in the toner containers  32 Y,  32 M,  32 C, and  32 K for an image forming apparatus that appropriately supplies two-component developer formed of toner and carrier to a developing device. Even for this case, the same advantages as described above can be achieved. 
         [0275]    In the above embodiments, a part or all of the image forming units  6 Y,  6 M,  6 C, and  6 K may be configured as process cartridges. Even for this case, the same advantages as described above can be achieved. 
         [0276]    In the above embodiments, the container body  33 Y is made rotatable so that toner contained in the container body  33 Y can be conveyed toward the opening A. However, the container body  33 Y may be configured such that the container body  33 Y is non-rotatably held by the toner-container holder  70  together with the cap unit  34 Y, and the container body  33 Y includes, inside thereof, a conveying member (for example, a conveying member that has a conveying coil or a plurality of conveying blades on a shaft portion and that rotates in a predetermined direction by a gear separated from the container body) for conveying toner toward the opening A so that toner contained in the container body  33 Y can be conveyed toward the opening A (see  FIG. 61 ). 
         [0277]    More specifically, as illustrated in  FIG. 61 , the toner container  32 Y mainly includes the container body  33 Y, a gear  44 Y, and the cap unit  34 Y (bottle cap). The opening A is arranged on the head portion of the container body  33 Y, and the gear  44 Y is rotatably arranged on the outer circumference of the opening A. The gear  44 Y engages with the driving gear of the body of the image forming apparatus  100  to rotate a coil  46 Y about an axis of rotation. The opening A is used for discharging toner contained in the container body  33 Y to the space inside the cap unit  34 Y. A rotary shaft  45 Y is integrally arranged on the gear  44 Y, and the spiral-shaped coil  46 Y (conveying coil) is connected to the rotary shaft  45 Y. One end of the rotary shaft  45 Y is supported by a bearing  34 Ya of the cap unit  34 Y. The coil  46 Y is extended from the opening A to the bottom portion inside the container body  33 Y. The gear  44 Y rotates around the container body  33 Y to thereby rotate the rotary shaft  45 Y and the coil  46 Y. Therefore, toner contained in the container body  33 Y is conveyed to the opening A side by a toner conveying force of the coil  46 Y. The gear  44 Y is inserted into the outer circumference of the opening A so as to be sandwiched by the container body  33 Y and the cap unit  34 Y. A rubber member  47 Y is disposed between the gear  44 Y and the container body  33 Y on the side of one of the faces of the gear  44 Y. A seal member  48 Y is disposed between the gear  44 Y and the cap unit  34 Y on the other side of the gear  44 Y. With this configuration, the sealing capability of the entirety of the toner container  32 Y is ensured. That is, it is possible to prevent toner from leaking through a gap between any pairs of the gear  44 Y, the container body  33 Y, and the cap unit  34 Y. 
         [0278]    The present invention can also be applied to the above toner container  32 Y similarly to the above embodiments. Accordingly, it is possible to achieve the same advantages of the above embodiments. 
         [0279]    In the above embodiments, in each of the toner supply devices  60 Y,  60 M,  60 C, and  60 K, the toner conveying path formed with the toner tank ( 61 Y), the toner conveyor ( 62 Y,  63 Y), and the toner-falling conveying path ( 64 Y) has a reversed N-character shape (similarly to the shape of the Russian letter  14 ) as illustrated in  FIG. 1  (an N-character shape when viewed from the rear side of  FIG. 1 ). The toner conveyer ( 62 Y,  63 Y) for each color is provided on the upper side of the process cartridge (the image forming unit  6 Y) for the corresponding color, and on the upper side of the opening for attachment and detachment of the process cartridge to the body of the image forming apparatus  100 . The toner container ( 32 Y), the toner tank ( 61 Y) and the upstream side of the toner conveyor ( 62 Y) for each color are provided on the upper side of the nearby process cartridge (the left neighbor in  FIG. 1 ), not of the process cartridge for the corresponding color. With above configuration, in a tandem type image forming apparatus in which a plurality of process cartridges (image forming units) are arranged in parallel, a process cartridge (image forming unit) does not cause interference with the toner supply device when the attachment or detachment operation of the process cartridge is performed. In addition, it is possible to provide an image forming apparatus in which the layout of the toner containers and the process cartridges for the respective colors in the vertical direction can be achieved in a compact manner without variance in the amount of a toner supply. 
         [0280]    It is understood that the present invention is not limited to the above-described embodiments, and the embodiments can be readily modified within the range of the technical concepts of the present invention. The number, positions, shapes of elements are not limited to those in the embodiments. The number, positions, shapes of elements suitable for embodying the present invention can be employed. 
       INDUSTRIAL APPLICABILITY 
       [0281]    As described above, a toner container and an image forming apparatus according to the present invention is useful for an image forming apparatus such as a copying machine, a printer, and a multifunction peripheral that has functions of the copying machine and the printer, and is particularly suitable for an apparatus that has a mechanism in which powder such as toner is housed, attached and supplied to the apparatus, and a system including the apparatus.
A toner container and system for mounting and/or securing the toner container includes a toner container having a toner dispensing hole, a shutter, a protrusion. The shutter is movable relative to the toner dispensing hole, and is to selectively close the toner dispensing hole. The protrusion is connected to the shutter and movement of the protrusion causes the shutter to move relative to the toner dispensing hole to cover the toner dispensing hole. There is a receiver including a movable catch, the movable catch being in a first position when the toner container is initially inserted into the receiver, and the moveable catch moving to a second position upon insertion of the toner container into the receiver. The moveable catch interacts with the protrusion of the toner container when the toner container is being removed from the receiver such that the moveable catch in the second position restricts movement of the protrusion of the toner container which closes the shutter as the toner container is withdrawn from the receiver.