Other

Kanegafuchi Kagaku Kogyo Kabushiki Kaisha

Masaharu Iwai

Yasushi Kakehashi

Masami Hosokawa

Yoshio Sakata

Osamu Oshima

Shingo Inase

A process for preparing a magnet roller comprising a plurality of bar-like magnet pieces in a high working efficiency and in an improved adhesion accuracy, which comprises the steps of regulating the bonding position of at least two magnet pieces by their outer peripheral surfaces and their end surfaces, applying an adhesive from the inner surface side of the magnet pieces to the adhesion faces of the magnet pieces for bonding one magnet piece to another magnet piece to form a magnet block, and bonding and fixing the magnet block to a shaft. At least one of the adhesion faces which are in contact with each other may have a plurality of grooves to facilitate penetration of the adhesive into the interface of adjacent two magnet pieces.

Magnet roller and process for preparing the same

The object is to provide a magnet roller whereby picture quality can be improved by raising the magnetic flux density of the specified magnetic pole and/or other magnetic poles, and wherein this magnetic pole pattern can be achieved with low cost. In a magnet roller ( ) according to the invention that achieves this object, a plurality of magnet pieces ( ) are mounted at the periphery of a shaft ( ) by joining at joining faces and peaks ( ) of magnetic poles ( ) are generated on the lines of extension of joining faces ( ) by setting the directions of orientation magnetization ( ) of adjacent magnet pieces ( ) facing the joining faces ( ), the respective joining faces ( ) of the plurality of magnet pieces ( ) being provided along the roller radial directions.

Magnet roller

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

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.

Growing community of inventors

Mooka, Japan

Masaharu Iwai