This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 and xc2xa7120 arising from an application for Method For Testing nozzles of an Inset Printer earlier filed in the Korean Industrial Property Office on Apr. 9, 1996 and there duly assigned Ser. No. 10615/1996.
1. Field of the Invention
The present invention relates to a method for automatically testing whether or not nozzles of an inkjet printer are functioning properly, and reporting 1) whether there are any malfunctioning nozzles for a given print head, 2) the number of malfunctioning nozzles in a print head, 3) the number of functioning nozzles in a print head, and 4) which particular nozzles are malfunctioning, if any.
2. Description of the Prior Art
U.S. Pat. No. 4,996,487 for an Apparatus for Detecting Failure of Thermal Heaters in Ink Jet Printers to McSparran et al discloses a method and apparatus for testing heating elements of a thermal jet printing device. U.S. Pat. No. 4,907,013 for Circuitry For Detecting Malfunction of Ink Jet Printhead to Hubbard et al discloses a device and method for detecting nozzle malfunction in an inkjet printer. The results of a 32 nozzle printhead are stored in a 32 bit word. A value of xe2x80x9c0xe2x80x9d indicates that the nozzle is functioning properly and a value of xe2x80x9c1xe2x80x9d indicates that there is a malfunction with the nozzle. If the central processor is able to compensate for the malfunctioning nozzle(s), the printhead is stepped in the vertical direction and an additional pass is made over the print medium to fill in for the missing dots from the first pass. This condition is called a soft error and the printhead continues printing without notifying the user of the presence of a malfunctioning nozzle. If the central processor is unable to compensate for the malfunctioning nozzle, the printhead is disabled. This is referred to as a fatal error. U.S. Pat. No. 5,182,580 for Ink Jet Recording Apparatus With Abnormal State Detection to Ikeda et al discloses an apparatus for detecting an abnormality in the ink liquid passage. What is needed is a system that automatically tests whether each nozzle of a printhead is functioning properly, and reporting to the user 1) whether there are any malfunctioning nozzles for a given print head, 2) the number of malfunctioning nozzles in a print head, 3) the number of functioning nozzles in a print head, and 4) which particular nozzles are malfunctioning, if any. This information can be reported to the user via CRT display, Liquid Crystal Display (LCD), Light Emitting Diode (LED), printer, or storage into memory of a computer.
It is therefore an object to provide a system which tests the operability of each nozzle of a printhead, store the results in a bitmap in software, and notify the user whenever there is a malfunctioning nozzle.
It is also an object to provide a system which tests the operability of each nozzle of a printhead, store the results, store the results in a bitmap in software, and notify the user whenever there is a malfunctioning nozzle, even if the number of nozzles is more than 32.
It is still an object to provide a system which automatically tests each nozzle of a print head to determine whether each nozzle is malfunctioning, and to display, print, and record the number of malfunctioning nozzles.
It is still yet an object to provide a system which automatically tests each nozzle of a print head to determine whether each nozzle is malfunctioning, and to display, print, and record the number of functioning nozzles.
It is still another object to provide a system which automatically tests each nozzle of a print head to determine whether each nozzle is malfunctioning, and to identify which particular nozzles are malfunctioning, and to display, print, and record the position and location of the malfunctioning nozzles.
This and other objects can be achieved by providing a circuit with a D flip flop that converts the operational state of a nozzle of a printhead into a bit to be stored in a word. A bit with a logic level of xe2x80x9c1xe2x80x9d indicates that a corresponding nozzle is working properly and a bit with a logic level of xe2x80x9c0xe2x80x9d indicates that a corresponding nozzle is malfunctioning. If any of the nozzles are malfunctioning, the user is made aware of the situation through an LED or an LCD panel.