Patent ID: 8879929

Claim:
An image forming apparatus comprising: a rotatable photosensitive member; a corona charger, including an opening, for electrically charging said photosensitive member by effecting electric discharge via the opening; a toner image forming portion for forming a toner image on said photosensitive member electrically charged by said corona charger; a sheet-like shutter for opening and closing the opening of said corona charger; moving means for moving said sheet-like shutter in a longitudinal direction of said corona charger; a potential sensor for detecting a potential of a portion of said photosensitive member chargeable by said corona charger, wherein said potential sensor is provided so as to be capable of detecting a potential of an end portion, of a region of a surface of said photosensitive member chargeable by said corona charger with respect to a rotational axis direction of said photosensitive member, at a downstream side with respect to a direction in which said sheet-like shutter moves when said sheet-like shutter closes the opening; a display portion for effecting display to an operator; and an executing portion for executing an operation in a mode in which the electric discharge by said corona charger is executed after said moving means effects control for closing said sheet-like shutter, and then a potential of the end portion of the surface of said photosensitive member opposing said corona charger when the electric discharge is executed is detected by said potential sensor, and thereafter, when the potential detected by said potential sensor is a predetermined value or more, error display is effected at said display portion.