Patent ID: 7274889

Claim:
An image forming apparatus for forming an image on a recording medium carried by a medium carrier, the image forming apparatus comprising: a photosensitive element; a charger which electrostatically charges a surface of the photosensitive element uniformly at a voltage of a polarity; an exposure device which exposes the surface of the photosensitive element as electrostatically charged by the charger, to a light, so as to form an electrostatic latent image; a developing device which deposits a developer of a color on the electrostatic latent image formed by the exposure device on the photosensitive element, to form a developer image; a transferring device which transfers the developer image on the photosensitive element onto the recording medium carried by the medium carrier; a developer removing device which comprises a cleaning member to which a cleaning bias voltage is applied to generate a cleaning bias as a value of a voltage bias between the cleaning member and the photosensitive element, to remove a waste developer adhering to the surface of the photosensitive element after the developer image is transferred onto the recording medium, the cleaning member being disposed to act on a part of the surface of the photosensitive element which has been charged by the charger and at which the developer image is not formed yet by the developing device, for removing the waste developer thereon; a cleaning bias reverser capable of reversing a polarity of the voltage bias between the cleaning member and the photosensitive element generated as a result of the application of the cleaning bias voltage to the cleaning member; a separator capable of moving the developing device away from the photosensitive element; a waste developer shifter which (i) makes the cleaning bias reverser to reverse the polarity of the voltage bias between the cleaning member and the photosensitive element from the polarity of the cleaning bias, at a timing when a part of the surface of the photosensitive element which will be brought into contact with an area on the medium carrier where the image is not to be formed in the recording medium, passes by the cleaning member, in order to repel the waste developer which has been once attracted onto the cleaning member back onto the photosensitive element, and (ii) makes the separator to move the developing device away from the photosensitive element, so that the waste developer repelled back onto the photosensitive element is discharged on the medium carrier; and a waste developer collector which collects the waste developer which has been discharged on the medium carrier.