Mita Industrial Co., Ltd.

Yuuji Hasegawa

Toshikazu Matsui

Akira Fushida

Masahiko Maeda

Nobuyuki Tsuji

Akira Horiuchi

Kazunori Yukitake

Disclosed is an electrophotographic process which comprises developing an electrophotographic light-sensitive layer having an electrostatic charge image of a certain polarity with a one-component type magnetic developer where positive and negative frictional charge polarities are mingled, under development bias voltage conditions capable of developing the electrostatic charge image, the background or both, and bringing the light-sensitive layer having a developer layer formed thereon into contact with a transfer sheet under a transfer charge of the same polarity as that of the electrostatic charge image when a positive image is formed or under a transfer charge of a polarity reverse to that of the electrostatic charge image when a negative image is formed, to form an image on the transfer sheet.

Method for forming negative and positive images in electrophotographic

The toner concentration of a two-component type developer including a mixture of a magnetic carrier and an electroscopic toner is adjusted by bringing a magnetic brush of the two-component type developer into sliding contact with a mesh screen to move the electroscopic toner toward the magnetic brush side or the opposite side through apertures of the mesh screen. Apparatus for adjusting the toner concentration in a two-component type developer includes a mechanism for forming a magnetic brush from a mixture of a magnetic carrier and an electroscopic toner and for delivering the magnetic brush. The mechanism includes a support formed of an electroconductive non-magnetic material and a magnet having a plurality of poles and being built in the interior of the support. At least one of the support and magnet is movable. A mesh screen is formed of an electroconductive material and is arranged to support the electroscopic toner on the upper surface side thereof and to have sliding contact with the magnetic brush on the lower surface side thereof. A bias voltage applying mechanism is provided for applying a bias voltage between the support and mesh screen.

Method and apparatus for adjusting toner concentration of two-component

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Kishiwada, Japan

Yuuji Hasegawa