Patent ID: 8412076

Claim:
An image forming apparatus comprising: a first image bearing member; a second image bearing member; a first development unit configured to contact the first image bearing member having a latent image formed thereon to develop the latent image; and a second development unit configured to contact the second image bearing member having a latent image formed thereon to develop the latent image; a change-over unit capable of changing over between a state where the first image bearing member is separated from the first development unit and a state where the first image bearing member is in contact with the first development unit to enable developing the latent image, and is capable of changing over between a state where the second image bearing member is separated from the second development unit and a state where the second image bearing member is in contact with the second development unit to enable developing the latent image; a detection unit configured to detect a first contact detection time from a time when the change-over unit starts to change the state where the first image bearing member is separated from the first development unit to a time when the change-over unit finishes changing the state to the state where the first image bearing member is in contact with the first development unit, and detect a second contact detection time from a time when the change-over unit starts to change the state where the second image bearing member is separated from the second development unit to a time when the change-over unit finishes changing the state to the state where the second image bearing member is in contact with the second development unit; and a control unit configured to control contact timing and/or contact speed between the first image bearing member and the first development unit according to the first contact detection time detected by the detection unit, wherein, after performing timing control for the first image bearing member and the first development unit, the control unit controls contact timing and/or contact speed between the second image bearing member and the second development unit according to the first and second contact detection times detected by the detection unit.