Patent ID: 8417162

Claim:
An image forming apparatus including an image forming unit comprising a plurality of image bearing members, a plurality of developing units capable of coming into contact with and separating from each of the plurality of image bearing members, an intermediate transfer member onto which toner images developed on the plurality of image bearing members by the plurality of developing units are transferred, and a plurality of transfer members which forms a plurality of nip portions with the plurality of image bearing members by sandwiching the intermediate transfer member, the image forming apparatus comprising: a pattern forming unit configured to form on the intermediate transfer member by employing the image forming unit a pattern for detecting positional deviation including a first color mark formed in which toner enters all of the nip portions of the plurality of image bearing members, and a second color mark formed in which toner enters a part of the nip portions of the plurality of image bearing members; a detection unit configured to detect positions of the first color mark and the second color mark included in the pattern for detecting positional deviation; and a correction unit configured to correct a relative velocity between the image bearing member and the intermediate transfer member based on a detection result of the detection unit, wherein a first relative velocity and a second relative velocity different from the first relative velocity can be set between the image bearing member and the intermediate transfer member, wherein the pattern forming unit forms the pattern at the first relative velocity and the second relative velocity, and wherein the correction unit corrects the relative velocity based on the pattern formed at the first relative velocity and the pattern formed at the second relative velocity, detected by the detection unit.