Canon Kabushiki Kaisha

Harumi Kugoh

Hideyuki Yano

Junji Araya

Tadashi Furuya

Yasushi Sato

Osamu Iwasaki

Akihiko Takeuchi

Hideo Nanataki

Hiroshi Sasame

Katsuhiro Sakaizawa

Toshio Miyamoto

Yukihiro Ohzeki

Hiroto Hasegawa

Katsuhiko Nishimura

Norio Hashimoto

Tatsunori Ishiyama

Takashi Shibuya

An electrophotographic apparatus includes a movable photosensitive member having a photoconductive layer, and a charging member for charging the photosensitive member. A latent image forming device forms an image on the photosensitive member, and an electric charge applying device applies an electric charge of a polarity opposite from a charging property of the charging member to the photosensitive member. The photosensitive member includes a rectifying layer on the photoconductive layer to provide, at an interface between the photoconductive layer and the rectifying layer, a p-n junction preventing electric charge of the opposite polarity from entering the photoconductive layer.

Electrophotography having photosensitive member with charge blocking

A charging apparatus includes a charging member for charging the member to be charged; a power source for supplying electric power to the charging member; a power source for supplying a constant small DC current to the charging member; and a device for determining a voltage to be applied to the charging member; wherein while the constant small DC current is supplied to the charging member, a voltage supplied to the charging member is detected and in response to the detected voltage, the voltage determining device determines the voltage to be applied to the charging member.

Image forming apparatus having a voltage controlled contact charger

An image forming apparatus includes an image bearing member for bearing an image, a contact charger for charging the image bearing member, and a detector for detecting an electric current flowing through the charger when the charger changes a potential of a predetermined area of the image bearing member from a first potential to a second potential which is different from the first potential. In another aspect of the invention, the detector detects a flow of current through a second contact charger when a first oscillating voltage is applied by a first contact charger and a second oscillating voltage applied by the second contact charger which is different from the first oscillating voltage.

Image forming apparatus having a contact charger for varying a charge

A charging member contactable to a member to be charged to electrically charge it includes a sponge layer; a coating layer disposed between the sponge layer and the member to be charged; wherein a cell diameter in a surface of the sponge layer coated with the coating layer is not more than 200 microns.

Charging member, charging device, process cartridge and image forming

A charging member for charging a member to be charged while being in contact therewith includes conductive base for being supplied with a voltage; a surface layer contactable to the member to be charged; a sponge layer between the conductive base and the surface layer; a 100% modulus M.sub.100 (kg/cm.sup.2) of the surface layer and a thickness d (cm) of the surface layer satisfied:

Charging member, process cartridge and image forming apparatus

A developing apparatus having a container for containing a one component developer, and a rotatable developing roller disposed facing an image bearing member to carry developer from the container to a development zone where it is supplied to an electrostatic latent image carried on an image bearing member. The developing roller includes a metal base member and a resin coating layer thereon in which fine conductive particles are dispersed. The developing roller has a surface including an end region adjacent an end of the roller, and an intermediate region. In the end region, the base member is not roughened and the resin layer is not provided. In the intermediate region, inside the end region, the base member is roughened and is coated with the resin layer. A sealing member is provided for preventing leakage of the developer from the container at the end of the developing roller, the sealing member being faced to the end region of the developing roller.

Developing apparatus having a coated developing roller

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Kawasaki, Japan

Harumi Kugoh