Kanto Denka Kogyo Co., Ltd.

Tokyo Shibaura Denki Kabushiki Kaisha

Hoganas Ab

Kenkichi Hara

Kazuyoshi Oka

Ulf F Engstrom

Mitsuhiro Katayama

Tamotsu Murakami

Tsugifusa Hashimoto

Shigeo Yokoe

Hidehiko Iinuma

Masatomo Hayashi

Svenn E Larssen

Svenn E Larrssen

This invention provides an Mg-based ferrite carrier composed of an environment-friendly material meeting environmental regulations, and an electrophotographic developer comprising the carrier. The carrier and the developer of this invention realize high image quality and improved gradation properties. This invention also provides a method for producing the Mg-based ferrite material having a saturation magnetization of from 30 to 80 emu/g and a dielectric breakdown voltage of from 1.0 to 5.0 kV, and having the composition of the formula (1). The above properties are obtained by controlling conditions of sintering and heating treatments. CaaMgbFecOd (1) wherein a, b, and c satisfy 0.10 b/(b+c/2) 0.85 and 0 R(Ca) 0.10; R(Ca) is expressed as R(Ca)=a&#x2dc;Fw(CaO)/(a&#x2dc;Fw(CaO)+b&#x2dc;Fw(MgO)+(c/2)&#x2dc;Fw(Fc2O3)) (Fw(A): formula weight of A j; and d is determined by oxidation numbers of Ca, Mg and Fe.

Mg-based ferrite, an electrophotographic development carrier containing the ferrite, and a developer containing the carrier

A novel carrier material useful in conjunction with a toner for preparing a two-component developer for electrophotographic processes is provided. The carrier comprises a spherical magnetite particulate material having a reduced metallic iron outer layer which is coated with an outermost resinous layer for conditioning the copying properties of the carrier.

Method of making carrier for use in electrophotographic developers

Carrier for use in electrophotographic developers

A carrier for use as a component in electrophotographic two-component developers which is improved in durability of the triboelectric property by coating the surface of the iron core particles of carrier with a resinous composition comprised essentially of an epoxy-hydroxy hydrocarbon resin and an acrylic resin.

Two-component resin system of acrylic and diene polymers for coating

A carrier for use as a component in electrophotographic two-component developers which is improved in durability of the triboelectric property by coating the surface of the iron core particles of carrier with a resinous composition comprised essentially of an epoxy-hydroxy hydrocarbon resin and a silicone resin.

Resin-coated carrier for use in two-component electrophotographic

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Gunma, Japan

Kenkichi Hara