Patent ID: 6928253

Claim:
An image forming apparatus comprising: an image bearing member; charging means that charges the image bearing member; a developing member that develops an electrostatic image formed on the image bearing member with a developer; transfer means that transfers a developer image developed by the developing member; and developer charging means which is located further on an upstream side than the charging means in a moving direction of a surface of the image bearing member and further on a downstream side than the transfer means and which charges the developer on the image bearing member, wherein the developer charging means reciprocates in a longitudinal direction of the image bearing member, and when a number of rotations per unit time of the image bearing member is assumed to be “a” and a number of times of reciprocation per unit time of the developer charging means is assumed to be “b”, assuming that R=b/a, a value of R is set in a range of 1/25≦R≦3 excluding R=m/n, wherein m and n are integers of 5 or less.