Patent ID: 7113713

Claim:
An image forming apparatus comprising: a first image bearing member for bearing a toner image; a movable second image bearing member; charging means which charges a toner on the second image bearing member; and voltage applying means which applies a voltage to the charging means, wherein the toner image is transferred from the first image bearing member to the second image bearing member at a first transfer portion, and the toner image is transferred from the second image bearing member to a transfer material at a second transfer portion, wherein the charging means is opposed to the second image bearing member at a downstream side of the second transfer portion and at an upstream side of the first transfer portion with respect to a moving direction of the second image bearing member, and wherein the voltage applying means switches a DC voltage from a first voltage to a second voltage which is opposite in polarity to the first voltage, the switching from the first voltage to the second voltage being executed at each of a predetermined number of transfers of the toner image from the second image bearing member to the transfer material, the predetermined number varying depending on an image forming condition.