Kyocera Corporation

Hiroyoshi Tode

Eiji Ochiai

Yoshio Ozawa

Akira Satoh

Hisashi Mukataka

Masahiro Nagata

Yukio Ikeda

Ryushi Imoo

Hidemasa Aiba

Masayoshi Yamada

Norio Tomiie

Makoto Hamaguchi

Image forming process and an image forming apparatus

A process for producing an image comprising the steps of: electrically charging a photoreceptor under dark; forming a latent image on the photoreceptor through selective imagewise exposure to light; and developing the latent image with a two-component developer comprising a carrier and a toner, the photoreceptor comprising a conductive substrate having thereon a photoconductive layer comprising amorphous silicon having a thickness of 25 .mu.m or less, the carrier is a magnetic material carrier comprising particles of a magnetic material having an average particle diameter of from 35 to 60 .mu.m, where the content of particles having a diameter of 44 .mu.m or more is 35% by weight or more. A two-component developer comprising a carrier and a toner, the carrier comprising particles of a magnetic material having an average particle diameter of from 35 to 60 .mu.m, where the content of particles having a diameter of 44 .mu.m or more is 35% by weight or more.

Process for producing image and two-component developer

To form sharp image free from flow of image or fog with an electrophotographic apparatus, which uses an a-Si photo-sensitive drum charged uniformly by having resort to the discharge phenomenon, the electrophotographic apparatus comprises an electrophotographic photo-sensitive drum having a surface layer being represented by an elementary ratio composition formula ( a-Si.sub.1-x C.sub.x :H ), x being 0.95.ltoreq..times.&lt;1, the dynamic indentation hardness of the upper surface layer being 300 kgf/mm.sup.2 or below, the hardness of said surface layer being higher on the inner side of said photoconductive layer than on the outer surface side, preferably being gradually increasing as one goes toward the inner side of said photoelectric layer from the outer surface side, and a developing unit using a developer composed of carrier and toner particles being caused to rub the drum surface and recovered said developer in a developer vessel. The temperature of said photosensitive drum surface and said developer vessel being held in a range 0 to +10.degree. C., the developer used for the development contained a conductive abrasive having a volume resistivity ranging from 10.sup.2 to 10.sup.10 .OMEGA..multidot.cm, the peripheral speed of a transfer roller is set to be slightly higher than the peripheral speed of the drum.

Electrophotographic apparatus

An image forming apparatus is disclosed, in which a photo-sensitive member is exposed by exposure means accommodated therein, and development is done substantially simultaneously with the exposure. Three time elements, that is, charging time constant C, i.e., time until reaching of a predetermined charging potential on of the photo-sensitive member in a brushing contact region between the photo-sensitive member and a toner holder after the start of charging, exposure time constant R, i.e., time until the charging potential is attenuated by the exposure to a latent image potential, and development time or time T, during which the photo-sensitive member passes by the brushing contact region, are appropriately determined. It is found that more satisfactory image formation is possible by setting C, R and T such as to meet relations

Image forming apparatus and method for obtaining smooth charging,

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Watarai-gun, Japan

Hiroyoshi Tode