Patent ID: 8160480
Filing Date: 2012-04-17
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a first rotatable image bearing member configured to bear a toner image; a second rotatable image bearing member configured to bear a toner image; a rotatable belt member which can abut on the first and second image bearing members; a drive mechanism configured to attach or separate the second image bearing member to or from the belt member; a first driving source configured to rotate and drive the first rotatable image bearing member; a second driving source configured to rotate and drive the second image bearing member; a belt driving source configured to rotate and drive the rotatable belt member; an execution unit configured to execute a first image forming mode in which an image is formed in a state where the first rotatable image bearing member is in contact with the rotatable belt member with a predetermined speed difference and the second rotatable image bearing member is in contact with the rotatable belt member with the predetermined speed difference and a second image forming mode in which an image is formed in a state where the first rotatable image bearing member is in contact with the rotatable belt member with the predetermined speed difference and the second rotatable image bearing member is separated from the rotatable belt member; and a control unit configured to control speeds so that a speed difference between the second rotatable image bearing member and the rotatable belt member is smaller than the predetermined speed difference, while forming an image by using the first rotatable image bearing member in a state where the first rotatable image bearing member is in contact with the rotatable belt member with the predetermined speed difference, when one of the first mode and the second mode is changed to the other mode.