Patent ID: 7266317

Claim:
An image forming apparatus, comprising: a first image forming device that forms an image using a first color toner; a second image forming device that forms an image using a second color toner; and a control device that controls the first image forming device and the second image forming device, wherein the control device controls the first image forming device and the second image forming device, so that at least one reference patch whose specified area is painted in the first color toner is formed by the first image forming device and at least one target patch whose specified area is painted in the second color toner is formed by the second image forming device, and a part of the reference patch and a part of the target patch are overlapped and a position where an overlap state between the reference patch and the target patch is changed varies in accordance with a change in a position in a first direction of a target patch forming position with respect to a reference patch forming positions, wherein the reference patch includes a reference patch border section as a border line approximately parallel to a second direction perpendicular to the first direction, the target patch includes a plurality of target patch border sections as border lines approximately parallel to the second direction, the plurality of target patch border sections being arranged so that positions of the plurality of the target patch border sections in the first direction and the second direction are shifted among plurality of the target patch border sections, and at least one target patch border section of the plurality of the target patch border sections is positioned on one side of the reference patch border section, at least one target patch border section, except the at least one target patch border section positioned on one side of the reference patch border section, is positioned on one of the reference patch border section and on the other side opposite to the one side of the reference patch border section.