Mita Industrial Co., Ltd.

Joji Matsumoto

Eiichi Inoue

Yasushi Kamezaki

Akira Fushida

Hitoshi Nishihama

Yuji Hasegawa

In an electrostatic photographic process comprising subjecting an electrostatic photographic photosensitive plate to the combination of negative charging, positive charging and imagewise exposure to form an electrostatic latent image of a positive polarity, said electrostatic photographic photosensitive plate having such charging characteristics that a photosensitive layer can be positively charged by sequential negative corona charging and positive corona charging and positive charging is rendered substantially impossible by irradiation with light, and then subjecting the so treated photosensitive plate to positive charging a predetermined number of times, whereby an electrostatic latent image is formed the predetermined number of times by imagewise exposure conducted once, if a zinc oxide-resin dispersion is used for the photosensitive layer of the photosensitive plate and predetermined amounts of a triphenylmethane basic dye and a silicone oil are incorporated in the photosensitive layer, the time required for negative charging can be shortened, and the charge potential at the time of positive charging can be increased and accumulation of the residual potential after irradiation with light can be reduced.

Multiple copy electrophotographic process using dye sensitized ZnO

A magnetic brush developing device for an electrostatic copying apparatus wherein a magnetic brush is formed on a surface of a developing roller includes a magnet roller rotating inside of a cylindrical sleeve which is located adjacent to the surface of an electrostatic latent image retaining member to which a developing material is circumferentially applied. The magnet roller stops at a rotary angle such that a bristle of the magnetic brush on the sleeve is spaced from the surface of the electrostatic latent image retaining member, whereby a bristle of the magnetic brush is prevented from remaining in contact with the electrostatic latent image retaining member. Thereby, the developing material is prevented from causing the surface of the electrostatic latent image retaining member to change chemically, the developing material is prevented from causing the electrical characteristics of the surface to fail, and the developing material is prevented from adhering to the surface.

Growing community of inventors

Neyagawa, Japan

Joji Matsumoto