Fuji Xerox Co., Ltd.

Fuji Photo Film Company, Limited

Shigeo Aonuma

Koichi Tanaka

Yoshimi Amagai

Hiroshi Takayama

Toshiaki Murofushi

Koichi Oyamada

Kenji Kobayashi

Hiroshi Nakazawa

Yasuji Fukase

Takaaki Kimura

Yasuhiro Ohya

An electrophotographic developer is disclosed, that contains toner particles and fine particles of tin oxide having an electrical resistivity of from 10.sup.2 to 10.sup.9 .OMEGA..cm. The developer ensures efficient image transfer and exhibits good developing ability.

Electrophotographic developer containing tin oxide

An electrophotographic two-component system developer is described, comprising a positive charging toner and a negative charging carrier of the dispersed magnetic powder type, wherein a hydrophilic alumina particle is adhered onto the surface of said positive charging toner and a negative charging carrier has a volume average particle diameter of from 30 to 80 .mu.m. The developer provides reduced toner cloud upon development processing and provides toner images free from fog.

Two component electrophotographic developer

Dry toners for use in electrostatic latent image development comprising a colorant in a resin binder are described, wherein said resin binder comprises a polyester containing --COOH groups in which at least one of the --COOH groups is replaced with nitrogen-containing compounds such as amines, ammonium salts, betaines, pyridinium salts, and azines. These toners are superior in development of negatively charged latent images and exhibit good low temperature fixability.

Dry electrophotographic toner comprising graft copolymer

A toner for developing an electrostatic latent image characterized by a vinyl copolymer whose acid value is in the range of about 5 to 100.

Toner for developing electrostatic latent image containing copolymer of

A dry toner that is heat-fixable and/or press-fixable is disclosed, comprising (a) a colorant; and (b) a graft copolymer comprising (i) a crystalline polymer having a melting point of from 45.degree. C. to 200.degree. C., which is prepared from one or more monomers selected from ethylene, propylene and vinyl acetate, and (ii) an amorphous polymer having a glass transition point of 45.degree. C. or more, which is prepared from one or more vinyl monomers.

Dry toners comprising a colorant and graph copolymer comprising a

An electrophotographic toner comprising a binder resin and a colorant dispersed therein wherein the binder resin comprises about 50 to 95% by weight of a low temperature melting, high fluidity resin having a number average molecular weight of about 1,000 to 4,000, a glass transition temperature of about 40.degree. to 60.degree. C. and a melt index at 110.degree. C. of about 50 to 200 g/10 min or a mixture thereof, and about 5 to 50% by weight of a high molecular weight polymer having a glass transition temperature of about 35.degree. to 60.degree. C. and a weight average molecular weight of more than about 500,000.

Electrophotographic toner comprising low and high molecular weight blend

A process for producing an electrophotographic toner composition comprising melt-kneading (a) a cross-linkable functional group-containing resin and (b) a colorant, with (c) a polyfunctional resin capable of reacting with the cross-linkable functional group-containing resin (a) or a low molecular weight cross-linking agent capable of cross-linking the cross-linkable functional group-containing resin (a), the amount of the polyfunctional resin or the low molecular weight cross-linking agent (c) being such that the amount of the functional groups present in the polyfunctional resin or the low molecular weight cross-linking agent (c) being equivalent to or less than equivalent to the amount of the functional group present in the cross-linkable functional group-containing resin (a); cross-linking by heating and generating a shearing force during melt-kneading to produce a slightly cross-linked colored resin such that the adhesion properties and the grindability of the slightly cross-linked colored resin are not deteriorated, and pulverizing the slightly cross-linked colored resin to produce the electrophotographic toner composition.

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Kanagawa, Japan

Shigeo Aonuma