An image forming apparatus includes: 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.