Patent ID: 7555252

Claim:
An image forming apparatus comprising: an image bearing body that is rotatable about a central axis thereof, and that bears a dot-like latent image, on a surface of the image bearing body, in each of a plurality of divided regions that are arranged in rows along a direction that intersects an axial direction of the central axis at a predetermined intersection angle; and a developer bearing roller that is rotatable in order to make visible, as a developer image, the dot-like latent images borne by the image bearing body, using a developer borne on a surface of the developer bearing roller, the developer bearing roller opposing the image bearing body such that an axial direction of the developer bearing roller is parallel to the axial direction of the image bearing body, and that includes a helical groove portion on the surface of the developer bearing roller, the helical groove portion being inclined at a predetermined inclination angle with respect to the axial direction of the developer bearing roller and being formed having a uniform pitch in the axial direction, wherein a value that is a tangent of the inclination angle divided by a ratio of a moving speed of the surface of the developer bearing roller to a moving speed of the surface of the image bearing body is different from a tangent of the intersection angle.