Patent ID: 8897660

Claim:
An image forming apparatus comprising: a latent image support; an optical scanning system configured to form an electrostatic latent image at a predetermined screen angle on a circumferential surface of the latent image support; a container configured to hold a binary developer; a development roller disposed so as to face the latent image support and form a development area in between, and configured to carry the binary developer from the container to the development area; and a control circuit configured to rotationally drive the development roller at a predetermined rotation speed during a development process, wherein, the development roller has depression portions and land portions on a circumferential surface, the depression portions and the land portions forming oblique grooves in the surface, and while the development roller is rotationally driven, the control circuit is configured to control the predetermined rotation speed such that a crossing angle approximates 90°, the crossing angle being formed by a screen line in the electrostatic latent image on the circumferential surface of the latent image support and an area where the land portion of the development roller substantially passes over the circumferential surface of the latent image support.