Patent ID: 9057976
Filing Date: 2015-06-16
Classification: G03G

Abstract:
1. An image forming apparatus comprising: an image bearing member configured to rotate while bearing an electrostatic latent image; a developer bearing member configured to rotate at a constant circumferential speed ratio with respect to the image bearing member while bearing a developer and to develop the electrostatic latent image; a developer supply member, which includes a foam layer at a surface and is arranged in contact with the developer bearing member, configured to rotate in a direction opposite to a rotation direction of the developer bearing member at a constant circumferential speed ratio with respect to the developer bearing member and to supply the developer to the developer bearing member; a first voltage application mechanism configured to apply a voltage Vdr to the developer bearing member; a second voltage application mechanism configured to apply a voltage Vrs to the developer supply member; and a control unit configured to control the first and second voltage application mechanisms, wherein the control unit is configured to shift a difference Vdif (=Vrs−Vdr) between Vrs and Vdr toward polarity opposite to normal charge polarity of the developer as S decreases, where S is an absolute value of a speed difference between a circumferential speed of the image bearing member and a circumferential speed of the developer bearing member.