Eastman-kodak Company

Lam J Ewell

Xin Wen

Douglas W Couwenhoven

The present invention generally relates to a method and apparatus for compensating for malperforming or inoperative ink nozzles in a multitone ink jet printhead so that high quality images are printed although some ink nozzles are malperforming or inoperative. Multitone printing is effected by printing a variety of droplets of varying volumes at a given pixel location. In compensating for a malperforming nozzle, a swath data signal is modified and one or more functional nozzles are assigned the printing data for a malperforming nozzle such that the volume of ink ultimately printed at pixel locations is substantially unchanged and the resulting image is free from degradation. Additionally, malperforming nozzles may be assigned values which represent the degree of image degradation that would be caused by printing with the malperforming nozzles, such that these values may be taken into consideration during the process of modifying the swath data signal for complementary recording.

Method of compensating for malperforming nozzles in a multitone inkjet printer

A method of compensating for malperforming nozzles in an inkjet printing device having a printhead with a plurality of nozzles, including a first nozzle which prints along a first path, and at least a second nozzle which is capable of printing along substantially the same path as said first path, said nozzles adapted to printing image pixels containing two or more states according to a swath data signal, wherein each state corresponds to a volume of ink that is desired to be emitted by a nozzle, comprising the steps of: assigning a state importance value to each state, said state importance value indicating the relative importance of printing the given state compared to printing other states; assigning a nozzle malperformance value to each nozzle, said nozzle malperformance value indicating the relative image quality penalty of using the given nozzle compared to using other nozzles; computing a modified swath data signal responsive to the swath data signal, the state importance value, and the nozzle malperformance value; and printing the image pixels according to the modified swath data signal.

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Rochester, NY, United States of America

Lam J Ewell