Kyocera Corporation

Eiji Ochiai

Yoshio Ozawa

Shoichi Sakata

Hiroyoshi Tode

Masayoshi Yamada

Makoto Hamaguchi

Toshinori Nishimura

Shigeki Tsukahara

Naoki Date

An image forming apparatus of non-contact developing method using two-component developer material which is capable of obtaining a clear image free from fogging, ghost and toner contamination. The image forming apparatus has at least one developing unit which includes a developing roll and a magnetic roll, the developing unit develops an electrostatic latent image on a photosensitive body with a toner thin layer formed on the surface of a developing roll wherein a toner thin layer forming region on the developing roll is smaller than a magnetic brush forming region on the magnetic roll. A high resistivity region is adjacent each end of the toner thin layer forming region on the developing roll. A control device controls a developer material replenishment and controls the biasing to the developing roll and magnetic roll.

Image forming apparatus that prevents attachment of toner to lateral sides of the developing roll

When image formation is performed by an apparatus comprising: a magnetic roll for generating a magnetic brush by carrier having toner adhering triboelectrically thereto, a developer roll on the surface of which a thin layer of the toner supplied by the magnetic brush is formed, and a photoreceptor onto which the toner of thin layer jumps selectively in accordance with the latent image thereon; positively chargeable toner of which charge amount is controlled in 5&tilde;20 &mgr;C/g is used, the surface potential of the photoreceptor is set to a range above 0 to 250 V, and the after exposure potential which is the potential right after the photoreceptor is exposed is in a range of 0&tilde; to 100 V.

Image forming process and apparatus and control method thereof

Image forming process and an image forming apparatus

A developing apparatus employing a three-pole stationary magnetic roller for use with a uni-component magnetic developer or toner. The apparatus includes a rotational sleeve which accommodates the stationary roller, a mixer disposed in a toner vessel for stirring the toner, and a toner layer thickness regulator disposed upstream in the sleeve rotation direction from the developing position at which the image on a photo-sensitive drum is developed. The magnetic roller has a developing pole located near the developing position, a blade-facing pole facing the toner layer thickness regulator, and a shield pole located downstream in the sleeve rotation direction from the developing position, where the blade-facing pole and the shield pole are of the opposite polarity to the developing pole. The blade-facing pole and the shield pole generate a repulsive magnetic field therebetween, where the toner that has been stirred in the vessel comes in contact with the sleeve.

Developing 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.

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Watrai-gun, Japan

Eiji Ochiai