Kyocera Mita Corporation

Other

Mita Industrial Co., Ltd.

Hidekazu Tamura

Takashi Nagai

Seiji Kikushima

Toru Takatsuna

Yoshiteru Hatase

Nobuaki Kawano

Hideaki Kawata

Hiroaki Moriyama

Kouzou Teramoto

Tomohide Iida

Hiroko Higuchi

Noriya Okamoto

The present invention provides a magnetic monocomponent developer which can obtain a stable conveying performance for a long period and an image forming method which uses the developer. In a magnetic monocomponent developer which is used in a developing unit which includes a developing vessel which accommodates a magnetic monocomponent developer therein, a developer carrying body which carries the magnetic monocomponent developer and conveys the magnetic monocomponent developer to a developing region, and a developer layer thickness restricting member which restricts a layer thickness of the magnetic monocomponent developer, the magnetic monocomponent developer includes toner particles which contain at least a binder resin and magnetic powder, and also includes following constitutions (a) to (c).

Magnetic monocomponent developer and image forming method

A magnetic one-component toner of the invention contains at least a binding resin and a magnetic powder, and has a volume average particle size of 6.0 to 9.0 &#x3bc;m, a compressibility of 15 to 50%, and a mean roundness of 0.950 to 0.960. The magnetic powder has at its surface a phosphorus element of 0.10 to 0.50% by weight. This toner is suitable for use in an image forming apparatus provided with a developer carrier made of stainless steel, or an image forming apparatus provided with an amorphous silicon photosensitive material. This toner has high transfer efficiency and less fog, thereby enabling to maintain image density for a long period of time, and form high image-quality image.

Image forming apparatus with a magnetic one-component toner

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

A magnetic carrier for electrophotographic developing agent wherein the surfaces of the magnetic core particles are partly coated with a thermosetting resin and a small amount of a low-melting or low-softening thermoplastic resin or wax, and at least recessed portions of the core particles are filled with these coating materials. The magnetic carrier has an electric resistance that is maintained within a range that is suited for forming the image, and suppresses the occurrence of spent toner.

Magnetic carrier for electrophotographic developing agent and method of

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Osaka, Japan

Hidekazu Tamura