An image forming apparatus forms high precision full color image by correcting the adhesion quantity of an image visualizing agent and a position shift of a visible image while performing printing process. The image forming apparatus includes an intermediate transfer unit; plural photoconductors; plural charging units; plural exposure units; plural developing units; plural first transferring units; and plural second transferring units. The intermediate transfer unit has a correction pattern image formed in a region outside a predetermined maximum document region in a direction perpendicular to the moving direction. A detector in the intermediate transfer unit detects the correction pattern image. A correction controller performs 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 passes a position beneath one of the units.