Patent ID: 7917045

Claim:
An image forming apparatus, comprising: an intermediate transfer unit; a plurality of photoconductors that are arranged along a moving direction of the intermediate transfer unit; a plurality of charging units that uniformly charge surfaces of the photoconductors; a plurality of exposure units that form electrostatic latent images exposed on the surfaces of the charged photoconductors; a plurality of developing units that supply image visualizing agents to the photoconductors retaining the electrostatic latent images, and form visible images on the photoconductors; a plurality of first transferring units that transfer the visible images formed on the photoconductors to the intermediate transfer unit; and a second transferring unit that transfers the visible images on the intermediate transfer unit to a recording medium; wherein the intermediate transfer unit includes a correction pattern image formed in a region out of a predetermined maximum document region of the intermediate transfer unit in a direction perpendicular to the moving direction in a state where a printing operation is continued, a detector is provided in the intermediate transfer unit at a position opposite to the correction pattern image for detecting the correction pattern image, a correction controller is provided for correcting, based on detection results of the detector, setting values of one or more of the charging units, the exposure units, and the developing units when a region corresponding to an interval between the visible images formed on the photoconductors passes a position beneath one of the one or more of the charging units, the exposure units, and the developing units so that the setting values of the charging units are corrected when the region corresponding to the interval between the visible images formed on the photoconductors is passing the position between a charge start position and a charge end position of the charging units, the setting values of the exposure units are corrected when the region corresponding to the interval between the visible images formed on the photoconductors is passing the position between an exposure start position and an exposure end position of the exposure units, and the setting values of the developing units are corrected when the region corresponding to the interval between the visible images formed on the photoconductors is passing the position between a development start position and development end position of the developing units.