an object of the present invention is to provide an image forming apparatus which can achieve reduction in printing time , suppression of developer consumption , and implementation of silence . an image forming apparatus capable of forming a color image on an image carrier with use of developers of a plurality of different developing colors , including a plurality of developing devices respectively housing the developers of different colors , and a control section for controlling operation of the developing devices based on inputted image data , wherein the control section includes a concentration ratio recognition section for recognizing a concentration ratio of the respective colors for image data of every sheet from the image data , and controls so as to spare at least one color developer among the developers in response to the concentration ratio of respective colors recognized by the concentration ratio recognition section .