Patent ID: 7177573

Claim:
An image forming apparatus comprising: an image bearing member configured to bear latent images; a developing unit comprising: a plurality of developing devices configured to develop the latent images with respective developers to form visual images on the image bearing member, wherein each of the plurality of developing devices includes: a developer bearing member configured to bear the corresponding developer to develop the corresponding latent image; and a developer thickness controlling member which contacts the corresponding developer bearing member to control the thickness of a layer of the corresponding developer on the corresponding developer bearing member wherein when one of the plurality of developing devices performs a developing operation, the developer bearing member of said one of the plurality of developing devices is forwardly rotated and the developer bearing members of other developing devices of the plurality of developing devices, which do not perform a developing operation, are reversely rotated at a predetermined speed slower than the developer bearing member of said one of the plurality of developing devices forwardly rotated.