Patent ID: 8391758

Claim:
A color image forming apparatus comprising: a plurality of photoconductors arranged along an intermediate transfer belt; an exposure device to form electrostatic latent images on the plurality of photoconductors; a plurality of developing devices to supply a plurality of colors of developers to the electrostatic latent images formed on the plurality of photoconductors; a transfer device to transfer developer images formed on the plurality of photoconductors to the intermediate transfer belt; a plurality of mark sensing devices arranged between the plurality of photoconductors to sense a mark transferred to a non-image region of the intermediate transfer belt; and a controller to form and transfer the mark to the transfer belt and to determine, on the basis of sensing signals generated when the plurality of mark sensing devices sense the mark, an exposure time to form the electrostatic latent image on one of the photoconductors corresponding to one of the mark sensing devices that senses the mark, wherein the controller determines the exposure time by adding a predetermined time to the sensed time of the mark, and the predetermined time is a time required for the intermediate transfer belt to be fed by a distance between the mark and an image region of the intermediate transfer belt.