Patent ID: 8274698

Claim:
An image forming apparatus, comprising: an image input unit to input image data; a chase pattern generating unit to generate a chase pattern in which a plurality of chase pattern dots, each of which has a plurality of print dots, are arranged within a predetermined block; an overlay unit to overlay a plurality of chase patterns onto the image data; an image forming unit to form an image on a sheet based on the image data onto which the plurality of chase patterns is overlaid; and an overlaid position control unit to control an overlaid position of a chase pattern on the image data on N-th surface, wherein N is a natural number, of the sheet and (N+1)-th surface of the sheet, so as to shift the overlaid position by a shift amount that is equal to or more than a width of each of the chase pattern dots and equal to or less than an interval between the blocks of the chase patterns, if an edge of each of the sheets coincides with a position of at least one of the chase pattern dots, when full bleed image forming on both surfaces of a plurality of sheets is instructed.