Patent ID: 8139967

Claim:
An image forming apparatus, comprising: an image carrier being configured to carry a visible image formed with developer; an intermediate transfer part configured to provide a plurality of areas and a plurality of marks, each of the plurality of areas being arranged in a predetermined position with respect to at least one of the marks; a primary transfer part being configured to transfer the visible image from the image carrier to a first transfer area of the plurality of areas on the intermediate transfer part; a secondary transfer part being configured to transfer the visible image from the intermediate transfer part to a recording medium; a transfer area change part being configured to change the first transfer area to a second transfer area of the plurality of areas, wherein the first transfer area and the second transfer area are separated without an overlap; and a detector being configured to detect the marks, wherein the transfer area change part includes an area selection part and a switch part, the area selection part is configured to select one of the plurality of areas as the transfer area and set the position of the visible image based on a detected result by the detector, and the switch part is configured to switch the transfer area among the plurality of areas, and wherein the marks of the intermediate transfer part include at least a first mark and a second mark, and length of each of the first mark and second mark are different from each other in a moving direction of the intermediate transfer part.