| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus which is capable of preventing the generation of a creep to a surface of a developing roller even if a developing unit is stored for a long period in a state where it is not attached to a photoreceptor unit, and of changing pressing force towards the developing roller by a member contacting the developing roller uniformly with respect to the width direction of the developing roller when the developing unit is attached to the photoreceptor unit.SOLUTION: An image forming apparatus comprises a photoreceptor unit and a developing unit which is attachable to and detachable from the photoreceptor unit. The developing unit comprises a developing roller and a regulating blade. The developing roller comprises a metallic core, an elastic layer constituted of foam formed around the outer peripheral surface of the metallic core, and a sleeve formed on the outer peripheral surface of the elastic layer. The metallic core is configured to be capable of changing its position in such a manner that the center position of the metallic core of the developing roller and the center position of the sleeve are approximately the same when the developing unit is not attached to the photoreceptor unit and are different when the developing unit is attached to the photoreceptor unit. |
