US Patent 7591521 Image forming apparatus and method

This is an image forming apparatus provided with a recording head obtained by overlapping and disposing a plurality of short recording heads with a nozzle array composed of ink-jet nozzles arrayed in one direction, for jetting ink from the ink-jet nozzle, based on an image signal value and forming an image. The image forming apparatus comprises an overlap correction control unit for controlling drive of the ink-jet nozzles, according to a phase difference in a ink-jet nozzle position between the overlapped short recording heads to correct optical density of an image formed on an overlapped part of the recording heads and an optical density characteristic correction control unit for controlling drive of the ink-jet nozzles, according to a recording optical density characteristic of a nozzle array composed of the ink-jet nozzles independently of the overlap correction control unit.