Patent ID: 7316464

Claim:
An ink jet print apparatus for printing an image by ejecting ink from a printing head based on image data, the printing head having a plurality of nozzle groups, the plurality of nozzle groups being arrays of a plurality of nozzles for ejecting a liquid, the apparatus comprising: correction means for correcting an image to be printed by a nozzle group including a nozzle in a defective ejecting condition so that the image is printed using at least one nozzle group not including a nozzle in a defective ejecting condition among the plurality of nozzle groups, wherein said correction means performs data processing so that the image data corresponding to the nozzle in the defective ejecting condition and a part of the image data corresponding to a nozzle adjacent to the nozzle in the defective ejecting condition are printed by the at least one nozzle group not including a nozzle in a defective ejecting condition, with the nozzle group including the nozzle in the defective ejecting condition printing some image data after said correction means performs the data processing, and wherein said correction means performs a subtracting process on multi-valued data of pixels to be printed by the nozzle in a defective ejecting condition and pixels in the vicinity of those pixels, simultaneously performs an adding process for adding an equivalent amount of data to multi-valued data of pixels to be printed by the at least one nozzle group not including the nozzle in a defective ejecting condition, and thereafter quantizes the multi-valued data of the pixels.