Patent ID: 8150281
Filing Date: 2012-04-03
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: a plurality of image bearing members; a rotary member; developing devices capable of coming into contact with and separating from the respective image bearing members, the developing devices developing toner on the corresponding image bearing members; a patch detector configured to detect positions of toner patches, the toner patches being transferred onto the rotary member from the image bearing members, wherein a first toner patch and a second toner patch are transferred onto the rotary member from the plurality of image bearing members, the first toner patch being transferred onto the rotary member from a first image bearing member while all of the developing devices are in contact with the respective image bearing members and the second toner patch being transferred onto the rotary member from a second image bearing member while the developing device corresponding to the second image bearing member is in contact with the second image bearing member and the developing device corresponding to at least one of the plurality of image bearing members except for the second image bearing member is moving from a contact state to a separated state or moving from the separated state to the contact state; and a control device controls a peripheral velocity of the rotary member or a peripheral velocity of the image bearing members based on a position of the first toner patch and a position of the second toner patch detected by the patch detector.