Patent ID: 7031020

Claim:
A controller for outputting color image data to an image forming unit, said controller comprising: a communicator, arranged to perform bi-directional communication with the image forming unit; a status receiver, arranged to receive a status of the image forming unit by using said communicator; a decider, arranged to decide timing for calibrating a condition of color processing based on the received status; a transmitter, arranged to transmit a command, which indicates execution of calibration of the condition of color processing, to the image forming unit by using said communicator; a data receiver, arranged to receive patch data, obtained by measuring one a patch formed by the image forming unit, from the image forming unit by using said communicator; a calculator, arranged to calculate controller color-correction data based on the received patch data; and corrector, arranged to perform color correction using the controller color-correction data so as to generate color image data to be outputted to said image forming unit, wherein the image forming unit has a central processing unit which controls the formation and measurement of the patch in accordance with the command received from said transmitter.