Sakata Inx Corporation

Koji Iwase

Takaaki Yodo

Hirohito Maeda

Hideo Shibata

Hideki Kinoshita

Teruhisa Sato

Katsutoshi Okamoto

Hiroyuki Ishikawa

Naoya Inazumi

Tomoaki Inoue

The present invention provides a method for producing a liquid developer for electrophotography or electrostatic recording obtained by a coacervation method, which sufficiently maintains the charging property and has good dispersion stability of colored resin particles, as well as a liquid developer obtained by the method. A method for producing a liquid developer by a coacervation method,

Method for producing liquid developer

Production process for a liquid developer for use in electrophotograph or electrostatic recording by coacervation method. The process can produce a liquid developer in which a coloring agent (e.g., a pigment) is included completely within a resin particle by distillation of a solvent while retaining the state where the coloring agent is finely dispersed and the resulting colored resin particle is small in particle size with excellent dispersion stability, and excellent optical properties.

Process for production of liquid developer, and liquid developer produced by the process

An object of the present invention is to provide a carbodiimide type compound having high dispersibility and dispersion stability of pigments, fine resin particles, and pigment-resin composite fine particles particularly in a silicone dispersion medium; a pigment dispersion composition and a pigment-resin composite fine particles-containing dispersion composition preferably usable in a wide range of fields such as inks for solvent ink jet, liquid developers, and the like by using the compound; and a liquid developer using such a pigment dispersion composition and/or pigment-resin composite fine particles-containing dispersion composition. The present invention provides a carbodiimide type compound obtained by introducing a polysiloxane chain by reaction of a functional group of a polysiloxane chain-containing compound having the functional group reactive with a carbodiimide group with a carbodiimide group of a carbodiimide compound having a carbodiimide equivalent weight of 100 to 50000.

Carbodiimide compound and use thereof

It is an object of the present invention to provide a liquid developer in which in liquid developers for electrophotography or electrostatic recording obtained using the coacervation method, electric resistance of the liquid developer and the electrophoretic property or the charging characteristic of the toner particles are adequately maintained, and the dispersibility of a pigment and the dispersion stability of the toner particles are good. A liquid developer formed by dispersing colored resin particles comprising at least a pigment, a dispersant and a resin in a hydrocarbon insulating medium using a coacervation method,

Liquid developer

A pigment dispersion is disclosed which comprises a pigment dispersant, a nonaqueous solvent and optionally a binder resin, wherein the pigment dispersion comprises as the pigment dispersion at least 0.2 parts by weight of a modified novolak resin (A) relative to 100 parts weight of the pigment, the modified novolak resin (A) having an aromatic ring and a ring structure given by ring opening of an epoxy group by a carboxyl group of a hydroxycarboxylic acid or a derivative thereof. An ink composition for offset printing containing the pigment dispersion is also disclosed.

Pigment dispersion and offset printing ink composition using the same

A pigment dispersion is disclosed which comprises a pigment, a pigment dispersant, and optionally a binder resin, wherein the pigment dispersion comprises as the pigment dispersion at least 0.2 parts by weight of a modified novolak resin (A) and/or a graft copolymer (B) relative to 100 parts by weight of the pigment, the modified novolak resin (A) and the graft copolymer (B) each having an aromatic ring and a ring structure given by ring opening of an epoxy group by a carboxyl group of a hydroxycarboxylic acid or a derivative thereof. An ink composition for offset printing containing the pigment dispersion is also disclosed.

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Osaka, Japan

Koji Iwase