Nippon Zeon Company, Ltd.

Takahiro Takasaki

Noboru Yanagida

Tokudai Ogawa

Jun Hasegawa

Kazuhiro Sato

Jun Sakai

Katsuya Nakamura

Masahiro Yamakawa

Fumio Takano

Kojiro Masuo

Kazu Niwa

Kenji Akimoto

Akira Honma

A non-magnetic one-component developer comprising a substantially spherical polymerized toner which contains at least a binder resin and a colorant and has features that the volume average particle diameter is 5 to 10 &mgr;m, the proportion of particles having a particle diameter of at most 5 &mgr;m is at most 25% by number, the proportion of particles having a particle diameter of at least, 16 &mgr;m is at most 2% by volume, the standard deviation of the number particle diameter distribution is at most 1.8, and the spheroidicity represented by a ratio (dl/ds) of a length (dl) to a breadth (ds) in a particle is 1.0 to 1.3, and suitable for use in a cleaning system concurrent with development, and a developing method according to thee cleaning system concurrent with development making use of the non-magnetic one-component developer.

Nonmagnetic one component developer and developing method

Polymerized toner and production process thereof

A polymerized toner of a core-shell structure that colored polymer particles containing a colorant are covered with a polymer layer, wherein the polymerized toner has features that (1) the content of tetrahydrofuran-insoluble matter is 60 to 95 wt. %, and (2) the weight average molecular weight of tetrahydrofuran-soluble matter as determined by gel permeation chromatography is 50,000 to 400,000, and a production process thereof.

Polymerization toner and process for producing the same

A toner for development of electrostatic images, comprising at least a binder resin, a colorant and a charge control agent, wherein the charge control agent is a polar resin composed of a copolymer of a vinyl monomer and SO X (X&equals;H or alkali metal) group-containing (meth)acrylamide and having an SO X group-containing (meth)acrylamide unit content of 0.1 to 10 wt. % and a weight average molecular weight of 17,000 to 25,000, and a production process of the toner.

Toner for development of electrostatic charge image and method for producing the same

A polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles which contain a compound having at least one >C&boxH;N,< structure in its molecule and a colorant, and a layer of a polymer having a glass transition temperature higher than that of a polymer component making up the core particles, said polymer layer covering each of the core particles, a production process thereof, an image forming process comprising using the polymerized toner, and an image forming apparatus containing the polymerized toner.

Polymer toner and method of production thereof

A polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles, which comprise a polyfunctional ester compound formed of a trifunctional or still higher polyfunctional polyhydric alcohol and a carboxylic acid, and a colorant, and shell which is formed of a polymer having a glass transition temperature higher than that of a polymer component making up the core particles and covers each of the core particles, a production process thereof, an image forming process comprising using the polymerized toner, and an image forming apparatus containing the polymerized toner.

Disclosed herein are a polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles having a volume average particle diameter (dv) of 0.5-20 .mu.m and a ratio (dv/dp) of the volume average particle diameter (dv) to a number average particle diameter (dp) of at most 1.7, and shell which is formed of a polymer layer having an average film thickness of 0.001-0.1 .mu.m and covers each of the core particles, and a production process thereof.

Process for producing polymerized toner

A binder for coating materials containing dispersed inorganic powder comprises a polyurethane resin containing (a) 2.2 to 7.0 terminal epoxy groups in one molecule in average and (b) 0.1 to 5.0% by weight as SO.sub.3 -- of a sulfonic acid salt group, 0.05 to 3.0% by weight as COO-- of a carboxylic acid salt group, or 0.02 to 1.0% by weight as N.sup.+ of a quaternary ammonium salt group in the molecule, and having a number-average molecular weight of 2,000 to 10,000. A coating material containing dispersed inorganic powder and a magnetic recording medium both use this binder. In a recording medium comprising a magnetic layer placed on a non-magnetic substrate, the magnetic layer comprises polyurethane resin (A) as a binder, vinyl chloride polymer (B) containing 0.1 to 20% by weight of epoxy group and having an average degree of polymerization of 100 to 500, as another binder, (C) an alicylic acid anhydride as a crosslinking agent, and (E) a tertiary amine as a catalyst, and at least one of the binders is crosslinked between the epoxy groups therein by the reaction in which components (C) and (E) take part. The coating material containing fine inorganic powder dispersed with stability and having a low viscosity can be obtained by using, as the binder, the polyurethane resin having terminal epoxy groups and one of a sulfonic acid salt group, a carboxylic acid salt group, and a quaternary ammonium salt group. The magnetic recording material prepared by using magnetic powder as the inorganic powder and crosslinking the binder is excellent in dispersion of the magnetic powder and smoothness of the surface. Therefore, the magnetic recording medium is excellent in magnetic properties, durability, and running properties.

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Kanagawa, Japan

Takahiro Takasaki