Abstract: The first transfer bias (opposite polarity to that of toner) is applied to a transfer roller to transfer a correction pattern on a photosensitive drum to the transfer roller. A toner adhesion amount sensor detects the adhesion amount of residual transfer toner which is not transferred and remains on the photosensitive drum. The first transfer bias is changed based on the deviation between the detected adhesion amount of residual transfer toner and its reference value. The second transfer bias (same polarity as that of toner) is applied to the transfer roller to transfer the correction pattern on the transfer roller to the photosensitive drum. The toner adhesion amount sensor detects the adhesion amount of reverse transfer toner upon reversely transferring the correction pattern on the transfer roller to the photosensitive drum by the second transfer bias. The second transfer bias is changed based on the deviation between the detected adhesion amount of reverse transfer toner and its reference value.

Abstract: A contact charger is in contact with a photosensitive body to charge the photosensitive body. Conductive nonwoven fabric is in surface-contact with the photosensitive body. A voltage is applied to the conductive nonwoven fabric through a conductive holder. The conductive nonwoven fabric has a surface resistivity of 10.sup.5 to 10.sup.7 .OMEGA./.quadrature., so that the photosensitive body can be charged to a predetermined potential with little charge unevenness.

Abstract: An image forming apparatus includes a discharger for discharging a surface of an photoreceptor, a shield case arranged opposite to the photoreceptor and having an opening opposite to the photoreceptor a corona wire electrode arranged in the shield case and connected to a high voltage power source, a charger arranged in the opening of the shield case and having a grid grounded through a constant potential element for charging the photoreceptor surface, and an electrode arranged opposite the photoreceptor between the discharger and the charger and having a sharp edge opposite the photoreceptor. The electrode is grounded through the constant potential element and generates an unbalanced electric field between the electrode and the photoreceptor, thereby discharging charges located on the photoreceptor surface and having a polarity different from that of the electrode.

Abstract: An image-forming apparatus that has a photosensitive drum. The drum is charged by a main charger to a surface potential Vo. A light beam bearing image information is applied after the transfer of the developed image and before the next image forming operation to facilitate cleaning thereof.

Abstract: An image forming apparatus according to the present invention comprises a photosensitive drum which is characterized by a charge generating layer and a charge transport layer. The drum is charged by means of a main charger. At this time, electric charge is produced and held in the charge generating layer. A light-beam bearing image information is applied to the charge generating layer of the drum through the charge transmission layer, by an exposure system. Thereupon, an electrostatic latent image corresponding to the image information is formed on the surface of the drum. The latent image is developed by means of a developing unit using a toner. Thus, a toner image is formed on the drum surface, from which it is transferred to the surface of a paper sheet by a transfer charger. The developing unit also serves to remove, simultaneously with the development of the electrostatic latent image, those toner particles remaining on the drum surface after the transfer by the transfer charger.

Abstract: An electrophotography apparatus of the present invention includes a movable photoconductive drum capable of carrying an electrostatic latent image on its surface, and a plurality of electrophotographic process means located along a moving direction of the photoconductive drum. A first or second static latent image is formed on the photoconductive drum charged by a main charger, at a first or second exposure radiating portion. In this case, the first and second exposure radiating portions are selectively operated in accordance with whether an original image is a positive or negative film, the first static latent image, formed at the first exposure radiating portion, is reversely developed by a first developing unit, and the second static latent image, formed at the second exposure radiating portion, is normally developed by a second developing unit.

Abstract: In an optical deflector of a polygonal mirror type, a cylinder rotatably overlaps on a fixed shaft with a gap between them. The cylinder rotates the polygonal mirror therewith. The cylinder is radially supported by a journal bearing of dynamic pressure type and axially suspended by a magnetic thrust bearing. The cylinder and the fixed shaft are made of nonmagnetic material, so that the cylinder is prevented from eccentric rotation because of local magnetization of cylinder and the shaft.