Konishiroku Photo Industry Co., Ltd.

Sekisui Chemical Co., Ltd.

Japan Synthetic Rubber Co., Ltd.

Hideaki Morita

Takahira Kasuya

Goichi Yamakawa

Makoto Tomono

Isao Furuta

Minoru Tsuneyoshi

Hiroyuki Takagiwa

Shinichiro Yasuda

Minoru Kohara

Hirozo Funaki

The present invention relates to toners for electrophotography wherein the main resin component comprises a lower molecular weight polymer and a higher molecular weight polymer each of which is different from the other wherein the higher molecular weight polymer has a glass transition point of at least 50.degree. C. and the lower molecular weight polymer has a glass transition point no higher than 65.degree. C. The above polymers comprise one or more polymers selected from styrene polymers, arcylic polymers, and styrene-acrylic copolymers. Generally, the lower molecular weight polymer has a weight average molecular weight of 50,000 or less and the higher molecular weight polymer has a weight average molecular weight of 80,000 or more.

Toner for electrophotography

The present invention relates to toners for developing electrostatically charged images which are comprised of a polyester binder resin condensed from diols of the formula ##STR1## with a polyhydric carboxylic acid or a derivative thereof wherein the polyhydric carboxylic acid is a mixture of dihyridic carboxylic acid or its alkylesters and about 30 mole % to about 80 mole % of the total acid content of more hydric carboxylic acids or therein hydrids.

Toner for developing an electrostatically charged image

An electrostatic image developing toner comprises a binder resin which contains at least 60% by weight of a styrene-butadiene copolymer. The copolymer contains a component A having a molecular weight of at least 100,000 in an amount of at least 20% by weight relative to the binder resin, and a component B having a molecular weight of at least 500,000 in the component A is not more than 15% by weight relative to the binder resin. The toner has adequate flowability and noncoagulation property and is capable of forming a superior visible image in a contact heat fixing system.

Electrostatic image forming toner

A method for manufacturing a toner for use in electrophotography comprising polymerizing a monomer to provide the polymer constituent of the toner in the presence of both a coloring agent and an anti-offset agent. Specific anti-offset agents are set forth and the toner made by the foregoing process is also disclosed.

Method for manufacturing toner for electrophotography

A toner for developing an electrostatic latent image comprising a resin prepared by emulsion polymerization of a first polymer to yield a first emulsion, emulsion polymerization of a second polymer to yield a second emulsion, mixing said first and second emulsions and coagulating said mixture, wherein said second polymer has characteristics different from those of said first polymer.

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Hachioji, Japan

Hideaki Morita