Image forming apparatus

摘要

An image forming apparatus includes a control unit controlling first and second voltage application mechanisms and shifting a difference Vdif (=Vrs−Vdr) between Vrs and Vdr toward polarity opposite to normal charge polarity of a developer as S decreases, where S is an absolute value of a speed difference between a circumferential speed of an image bearing member, which rotates while bearing an electrostatic latent image and a circumferential speed of a developer bearing member, which rotates at a constant circumferential speed ratio with respect to the image bearing member to develop the electrostatic latent image while bearing the developer, Vdr is a voltage that the first voltage application mechanism applies to the developer bearing member, and Vrs is a voltage that the second voltage application mechanism applies to the developer supply member.

主权项

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.