Patent ID: 7844200

Claim:
An image forming apparatus comprising: an electrophotographic photosensitive member; a contact charging member being in contact with the electrophotographic photosensitive member, for charging the electrophotographic photosensitive member; a charging voltage applying device for applying a direct current voltage to the contact charging member; a charging current detecting device for detecting an electric current flowing through the contact charging member; a pre-exposure device for exposing the electrophotographic photosensitive member to light to remove residual charge on the electrophotographic photosensitive member; and a control device for controlling an exposure light amount of the pre-exposure device, wherein the control device applies the direct current voltage from the charging voltage applying device to the contact charging member during a non-image formation to charge the electrophotographic photosensitive member, changes in a plurality of steps the exposure light amount of the pre-exposure device for the charged electrophotographic photosensitive member to form regions of the electrophotographic photosensitive member exposed with different exposure light amounts, and, based on a result of detection by the charging current detecting device when the regions of the electrophotographic photosensitive member exposed with the different exposure light amounts are charged by the contact charging member, the control device controls an exposure light amount of the pre-exposure device in an image formation.