Kanegafuchi Kagaku Kogyo Kabushiki Kaisha

Yasushi Kakehashi

Yoshio Sakata

Masaharu Iwai

Shogo Miki

Yasunori Matsunari

Toshiaki Ishimaru

A developing cylinder used in an electrophotographic developing device is improved in the efficiency of separation of a developer on its surface. A magnetic working force functioning to separate the developer from a sleeve surface is designed on the basis of a magnetic attraction force which results from a vector composite force consisting of a radial magnetic flux density and a tangential magnetic flux density on the sleeve surface and actually controls the behavior of the developer. The magnetic working force acting on a separation zone of weak magnetic flux density is made to act as a magnetic repulsion force functioning to separate the developer from the sleeve surface. The magnetic working force acting on a given area inclusive of a spot proximate to a photoconductor in a development zone is made to act as the magnetic repulsion force functioning to separate the developer from the sleeve surface. A magnet having a weak magnetic flux density pole is disposed in a developing zone and two strong magnetic flux density poles are disposed adjacent the weak magnetic flux density pole.

Developing device having developing cylinder with weak magnetic pole and

A machine part used as a magnet roll for developing and a process for producing the same. The machine part constitutes a member of a developing machine for an electrophotographic process such as a copier and facsimile, and a laser printer as well. The machine part comprises a shaft having a resin-bonded magnet layer provided on the outer periphery thereof. The composite molding of a resin-bonded magnet is produced by molding and establishing a composition for a thermoplastic resin-bonded magnet comprising from 35 to 60 % by volume of a thermoplastic resin and from 40 to 65 % by volume of a hard ferrite powder into a cylinder of uniform thickness on the outer periphery of a shaft, obtained is a thin resin-bonded magnet layer having a surface roughness of 5 .mu.m or less and free of seams which have generated during molding, the thin resin-bonded magnet layer further having provided on the surface a plurality of magnetic poles at a small spacing.

Composite molding of resin-bonded magnet for machine parts and process

An electrophotographic development process is disclosed, in which a visible toner image is fixed after it is transferred onto transfer members, the visible toner image being formed by a development device equipped with a photosensitive substance for forming a latent image and a visible image, a magnetic field source device, arranged in the vicinity of the photosensitive substance, having a movable member for conveying a developer on the surface and forming magnetic brush, a developement container supporting the magnetic field source device and a developer regulating plate, the improvement wherein the developer is a mixture of carriers and toner, and wherein the carrier are at least one of spherical, substantially spherical, and flake-like shapes and a mixture of at least one kinds of carriers ranging from 30 to 150 .mu.m in average grain size. According to the present invention, motor load is reduced by torque drop, a stirring device and its accessory parts are omitted, and as a result, the development device can be made compact and less costly.

Electrophotographic development process

At least one pair of adjacent magnets, magnet A of which serves both as an assistant magnet and a main magnet for a necessary magnetic pole is arranged so that it may have a magnetic component in the right angle direction with respect to the magnetized direction of another magnet B. Magnet A itself forms not only the main magnetic pole, but also is adapted to increase the flux density of magnet B in the outer circumference direction.

Growing community of inventors

Mooka, Japan

Yasushi Kakehashi