Other

Mita Industrial Co., Ltd.

Hiroko Higuchi

Toru Takatsuna

Yukihiro Mori

Takashi Nagai

Seiji Kikushima

Hiroaki Moriyama

Kouzou Teramoto

Kazushige Inoue

Hidekazu Tamura

Noriya Okamoto

Etsuro Nakagawa

A developing apparatus has a developer supporting member with a surface roughness R in the range from 3.0 to 5.5 &mgr;m and a one-component developer T with a bulk density in the range from 0.35 to 0.55 g/ml, and an image is developed by forming a layer of the developer T on the developer supporting member . This makes it possible to form a thin toner layer stably despite changes in ambient conditions, and to prevent low image density and fogging. The absolute value of the amount of electric charge with which the developer T is charged is preferably in the range from 3.0 to 10.0 &mgr;C/g. The developer supporting member is made preferably of stainless steel.

Developing apparatus and image forming apparatus employing it

This invention provides an electrophotographic toner comprising the polyester resin being fixing resin and the electric charge control resin having the functional group that endows positively charging property to the toner, in which the polyester resin has an acid value of not more than 10 mgKOH/g and a hydroxyl value of not more than 40 mgKOH/g, and the functional group is present in 2 to 5 mol % in the electric charge control resin. This electrophotographic toner has stable positively charging property, so that good image is obtainable.

Electrophotographic toner and contact development method using the toner

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Osaka, Japan

Hiroko Higuchi