Dainippon Ink and Chemicals, Incorporated

Other

Dainippon Ink Chemicals, Inc.

Kinji Shinzo

Hideki Watanabe

Yoshinori Shimane

Hiroyuki Terada

Masanobu Nakamura

Toshiro Kogawara

Seiichi Uno

Minoru Nomura

Ryozo Sugawara

Kazuya Kuriyama

Takashi Ito

Satoshi Ogawa

Masahiko Kubo

Kazuo Itoya

Tadayuki Sawai

Shinji Amaya

Hitoshi Takayanagi

Nansei Tashiro

Koichiro Matsuki

Masanobu Fukuda

Hideki Gambayashi

Kenichi Hirabayashi

Yukiko Soma

Yoshiyuki Iwanari

Seiichi Shimizu

Hiroko Sakurai

Katsuyuki Ogura

Hiroyuki Ohminato

Munekazu Hayashi

Shunichi Hiraishi

Hiroyuki Mariko

Norio Aoki

Syuuichi Yamazaki

Hiroshi Utsumi

Ryouzo Sugawara

The present invention provides a method for producing an aqueous dispersion of thermoplastic resin microparticles containing considerably less residual solvent remaining in resin particles, and a toner for electrophotography containing considerably less residual solvent. A self-water-dispersible thermoplastic resin is swollen using an organic solvent having a boiling point lower than 100&#xb0; C., which does not dissolve but can swell the self-water-dispersible thermoplastic resin, to produce a swollen material and the resulting swollen material is dispersed into an aqueous medium in the form of microparticles to produce an initial aqueous dispersion, and then the organic solvent is removed from the initial aqueous dispersion to prepare a dispersion. A toner for electrophotography contains microparticles obtained by separating microparticles of the self-water-dispersible thermoplastic resin from the aqueous dispersion of thermoplastic resin microparticles and drying the microparticles.

Method for producing aqueous dispersion of thermoplastic resin microparticles and toner for electrophotography

A toner for electrophotography comprises: a coloring agent and a binding resin comprising a polyester resin constituted of cyclohexanedimethanol as an essential polyol component, wherein the toner has, at 110&deg; C., a storage elastic modulus of 3&times;10 Pa or less and a loss elastic modulus of 6&times;10 Pa or less, and, at 150&deg; C., a storage elastic modulus of 1&times;10 Pa or more and a loss elastic modulus of 1&times;10 Pa or more.

Toner for electrophotography

Use of a polyester resin obtained by reacting a divalent or higher epoxy compound, a dibasic or higher polybasic acid compound selected from a polybasic acid and/or acid anhydride and/or lower alkyl ester thereof, and a divalent or higher polyvalent alcohol in a toner for electrostatic charge development containing at least a binder resin, a colorant, and a charge control agent can provide a toner for a non-magnetic single component development having excellent fixing properties, offset resistance and development durability.

Toner for non-magnetic single component development

An electrostatic image developer is provided which has superior fixation properties and anti-offset properties, exhibits stable charge behavior even during continuous printing, and has superior durability and permits a high-quality image to be obtained. This electrostatic image developer is a toner composition containing colored resin particles comprising at least a binder resin, a colorant, and a charge control agent, wherein (1) an epoxy compound with a valence of 5 or more, (2) a polybasic acid compound having a valence of 2 or more selected from the group consisting of polybasic acids and/or acid anhydrides and/or lower alkyl esters thereof, and (3) a polyvalent alcohol having a valence of 2 or more, are employed as chief structural components of the binder resin, and a polyester resin is produced by reacting components (1)-(3) simultaneously, or by first reacting components (1) and (3), and subsequently reacting component (2), or by first reacting components (1) and (2), and subsequently reacting component (3).

Toner composition and developer for electrostatic image development

Disclosed are an electrophotographic toner which is a spherical particle comprising a binder resin having encapsulated therein a colorant and has a volume average particle size of from 3 to 12 .mu.m, the binder resin being a non-crosslinked styrene-acrylic resin having an acid value of from 30 to 120, containing from 5 to 60% by weight of the components having a molecular weight in terms of polystyrene by gel permeation chromatography of 200,000 or more and having a ratio (Mw/Mn) of the weight-average molecular weight Mw to the number-average molecular weight Mn of from 4 to 30; and a process for preparing an electrophotographic toner comprising spherical particles having a volume average grain size of from 3 to 12 .mu.m, the process comprising mixing a mixture comprising the above-described resin, a colorant, a wax and an organic solvent as essential components with an aqueous medium in the presence of a neutralizer in an amount sufficiently large to render the resin self-emulsifiable to effect phase inversion emulsification, thereby producing particles each comprising a binder resin having encapsulated therein a colorant and a wax in the liquid medium, and separating and drying the particles. The toner obtained by the present invention is improved in the thermal fixing characteristics and the environmental stability of charging, exhibits a wide fixing temperature width at the heated roll fixing and has excellent triboelectricity.

Electrophotographic toner and process for the preparation thereof

A novel manufacturing method for toner used in electrophotography employing no organic solvent is disclosed. The method comprises the steps of: (1) combing a colored melted resin (a) and an aqueous medium (b), wherein the colored melted resin (a) is prepared by heating and melting a kneaded material containing a synthetic resin for use in an electrophotographic toner having an ionic group and a coloring pigment, and the aqueous medium (b) contains a substance capable of neutralizing the ionic group, and possesses a raised temperature not lower than the softening point of the synthetic resin by way of heating with application of pressure where necessary; (2) dispersing the colored melted resin (a) in the aqueous medium (b) by mechanical means while maintaining a mixture of the colored melted resin (a) and the aqueous medium (b) at a temperature not lower than the softening point of the synthetic resin; (3) producing an aqueous suspension of colored resin microparticles by means of sudden cooling; (4) separating the colored resin microparticles from the suspension; and (5) drying the separated colored resin microparticles.

Manufacturing method for toner used in electrophotography

A toner containing at least a colorant and a resin, in which the resin is a polyester resin having a total acid radical content of 2 to 50 mg equivalents per 100 g and having a weight-average molecular weight of 2,000 to 100,000, and the toner particles are spherical and have an average particle diameter of 3 to 13 .mu.m. The toner is produced by a process comprising adding an aqueous medium to a dispersion of at least a colorant and an anionic self-emulsifiable resin in a water-miscible organic solvent to cause phase inversion to obtain an emulsion, and separating the produced particles from the aqueous medium, followed by drying, in which the anion self-emulsifiable resin is a polyester resin having a neutral salt structure, having a total acid radical content of 2 to 50 mg equivalents per 100 g and having a weight-average molecular weight of 2,000 to 100,000.

Toner for developing electrostatic latent image and process for

A toner for developing electrostatic images and a process for producing the same is disclosed. The process comprises after applying ultrasonic waves to raw materials-mixture comprising addition polymerizable monomer(s), coloring agent(s) and water as indispensable components in the course of charging the raw materials-mixture into a reaction vessel or to a raw materials-mixture in a reaction vessel, at an application amount of from 0.05 to 50 W/l/hr. per unit treating volume and time using an ultrasonic homogenizer having frequencies of from 10 kHz to 50 kHz, subjecting the raw materials-mixture to suspension polymerization.

Process of producing electrophotographic toners comprises ultrasonic

A color toner composition for developing electrostatic images comprises a coloring agent and a binder resin, wherein the binder resin is a vinyl-modified polyester resin obtained by graft polymerizing

Color toner composition for developing electrostatic images

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Sakura, Japan

Kinji Shinzo