US Patent 7316464 Ink jet print apparatus and ink jet print method

In an image area printed by a nozzle group including a defective nozzle, pixels printed by the defective nozzle and part of pixels located in the vicinity of the same are printed by another nozzle group. As a result, since printing is performed not only at the pixels printed by the defective nozzle but also at the pixels in the neighborhood thereof simultaneously by separate nozzles, irregularities of printing attributable to interpolation are distributed even when there is a relative misalignment between the nozzle groups. It is therefore possible to obtain a preferable image without any increase in output time even when a printing head including a defective nozzle is used.