Minolta Company, Ltd.

Minolta Camera Kabushiki Kaisha

Konica Minolta Business Technologies, Inc.

Konica Minolta, Inc.

Konica-minolta Holdings, Inc.

Masahiro Anno

Minoru Nakamura

Chikara Tsutsui

Katsunori Kurose

Hiroyuki Fukuda

Makoto Kobayashi

Junji Machida

Eiichi Sano

Chiaki Yamada

Masahiko Nakamura

Kenichi Onaka

Yoshihiro Mikuriya

Masahide Inoue

Junya Onishi

Naoki Yoshie

Tsuyoshi Uchida

Naoya Tonegawa

Yukiko Uno

Hiroshi Mizuno

Toshiya Natsuhara

Toshitaro Kohri

Junji Ohtani

Kenji Hayashi

Hideaki Ueda

Yoshitaka Sekiguchi

Takeshi Arai

Junichi Tamaoki

Keiko Momotani

Yasuhiro Ohno

Ken Tanino

Mikihiko Sukeno

Hideo Hotomi

Eiichi Yoshida

Satoshi Uchino

Chiyoshi Nozaki

Takeo Oshiba

Shinya Obara

Tomoko Mine

Kaori Soeda

Okushi Okuyama

Kenichi Kido

Fumio Masuda

Satoshi Matsumoto

Yoshihisa Terasaka

Kazuo Ota

Sho Kim

Masaaki Oka

Miyuki Hotta

Yuya Kubo

Takanori Tanaka

Atsushi Yamamoto

Masayuki Hagi

Kouji Sugama

Yuji Enoguchi

Masafumi Uchida

Ryuichi Hiramoto

Yukio Hosoya

Kazuyoshi Goan

Tetsuo Sano

Kouichi Etou

Takao Yamanouchi

Makoto Nomiya

Hiroyuki Yamasaki

Megumi Aoki

Kunitomo Sasaki

Yukio Tanigami

Masahiro Matsuoka

Kouichi Sugama

Yuya Iwagoe

Shigeyuki Hakumoto

So Matsuya

Shino Hirao

Yoahihiro Mikuriya

A developer for electrostatic latent image contains toner particles. The toner particles contain a resin and a coloring agent, and the coloring agent includes a first coloring agent, a second coloring agent, and a third coloring agent. The first coloring agent is carbon black, the second coloring agent is one or more of C. I. Pigment Violet 19 and C. I. Pigment Violet 23, and the third coloring agent is one or more of C. I. Pigment Brown 23 and C. I. Pigment Brown 25. A content of the second coloring agent is not lower than 8 mass % and not higher than 25 mass % with respect to a total amount of the coloring agents.

Developer for electrostatic latent image

A liquid developer is characterized in that it includes toner particles and an insulating liquid, the toner particles include a resin and a pigment, the pigment includes a first pigment and a second pigment, the first pigment is carbon black, the second pigment is C.I. Pigment Brown 23 and/or C.I. Pigment Brown 25, and 20 to 60% by mass of the pigment is included relative to the toner particles.

Liquid developer

A liquid developer contains an insulating liquid and toner particles dispersed in the insulating liquid. The toner particles have a resin and a coloring agent. The resin contains at least 10 mass % and at most 40 mass % of an aliphatic polyester resin and at least 60 mass % and at most 90 mass % of an aromatic polyester resin. The resin has an acid value not less than 20 mgKOH/g and not more than 100 mgKOH/g. A difference in acid value between the aliphatic polyester resin and the aromatic polyester resin is not less than 0 mgKOH/g and not more than 10 mgKOH/g.

An image formation method includes a step of preparing an electrostatic latent image developer, a transferring step, and a fixation step. The step of preparing an electrostatic latent image developer includes a step of preparing an electrostatic latent image developer containing toner particles having prescribed viscoelasticity characteristics. The fixation step includes steps of heating a recording medium and fixing the toner particles to the recording medium at a pressure not lower than 200 kPa and not higher than 800 kPa.

Image formation method and image formation apparatus

A liquid developer includes an insulating liquid and toner particles dispersed in the insulating liquid. The insulating liquid has a flash point not lower than 100&#xb0; C. The toner particles contain a resin, and the resin contains 80 mass % or more of a first resin containing a component derived from a polyester resin. A solid content of the liquid developer corresponding to a portion of the liquid developer excluding the insulating liquid satisfies relation of G'(T)/G&#x2032;(T+10)&#x2267;10 (50&#xb0; C.&#x2266;T&#x2266;70&#xb0; C.), where G&#x2032;(T) represents a storage elastic modulus at a temperature T(&#xb0; C.) and G&#x2032;(T+10) represents a storage elastic modulus at a temperature (T+10) (&#xb0; C.).

A liquid developer includes an insulating liquid and toner particles which are dispersed in the insulating liquid and contain a resin and a coloring agent. The resin contains a first resin which is a resin containing a component derived from a crystalline polyester resin. The coloring agent contains carbon black and nigrosine. The toner particles have a peak at not lower than 30&#xb0; C. and not higher than 50&#xb0; C. in a DSC curve in temperature decrease.

Toner for developing an electrostatic latent image contains toner particles, the toner particles contain a resin and a pigment, the pigment includes a first pigment and a second pigment, the first pigment is carbon black, and the second pigment is C. I. Pigment Brown 23 and/or C. I. Pigment Brown 25.

Toner for developing electrostatic latent image

Toner for developing an electrostatic latent image contains toner particles, the toner particles contain a resin and a pigment, the pigment includes a first pigment, a second pigment, and a third pigment, the first pigment is carbon black, the second pigment is C. I. Pigment Brown 23 and/or C. I. Pigment Brown 25, and the third pigment is nigrosine.

An electrostatic latent image developer of the present invention includes a resin, a colorant and a colorant dispersant, wherein the colorant dispersant contains a first polymer compound containing a constitutional unit derived from a monomer A, a constitutional unit derived from a monomer B and a constitutional unit derived from a monomer C, the monomer A is 4-vinylpyridine, the monomer B is CH&#x2550;CR&#x2014;COOR(where Rrepresents hydrogen or a methyl group; and Rrepresents an alkyl group having 1 to 10 carbon atoms), and the monomer C is CH&#x2550;CR&#x2014;COOR(where Rrepresents hydrogen or a methyl group; Rrepresents (CHCHO)CHor (CHCHO)CHCH; and n represents an integer of 12 to 18).

Electrostatic latent image developer

A liquid developer includes toner particles and an insulating liquid, the toner particles include a resin and a pigment, the resin includes a crystalline resin, the pigment includes a first pigment, a second pigment, and a third pigment, the first pigment is carbon black, the second pigment is C.I. Pigment Brown 23 and/or C.I. Pigment Brown 25, the third pigment is nigrosine, and 20 to 60% by mass of the pigment is included relative to the toner particles.

A liquid developer is obtained by dispersing toner particles containing at least a resin and a coloring agent in an insulating liquid. The toner particles have a core-shell structure that first resin particles containing a first resin are attached to or cover surfaces of second resin particles containing a second resin. The coloring agent contains nigrosine. A content of nigrosine in the toner particles is not lower than 1 mass % and not higher than 20 mass %. The second resin satisfies Equations (1) to (2) below. In Equations (1) to (2), x represents a number average molecular weight of the second resin and y represents a urethane group concentration (mass %) in the second resin.&#x2212;0.00003+2.03&#x2266;&#x2266;&#x2212;0.00003+6.95&#x2003;&#x2003;Equation (1)10000&#x2266;&#x2266;60000&#x2003;&#x2003;Equation (2)

A liquid developer of the present invention includes a toner particle and an insulating liquid, the toner particle including a resin and a pigment, the resin including a polyester resin, the pigment including a first pigment, a second pigment, and a third pigment, the first pigment being a carbon black, 10 to 25 mass % of the first pigment being included in the toner particle, the second pigment being nigrosine, 3 to 15 mass % of the second pigment being included in the toner particle, the third pigment being at least one organic pigment selected from a group consisting of a phthalocyanine blue pigment, a phthalocyanine green pigment, a carmine-based pigment, a naphthol-based pigment, a quinacridon-based pigment, an azo-based pigment, a benzimidazolone-based pigment, and an isoindoline-based pigment, 5 to 20 mass % of the third pigment being included in the toner particle.

A liquid developer used for wet-type image forming apparatuses includes toner particles and an insulating liquid, the toner particles include a resin, a pigment, and a pigment dispersant, the pigment includes a pigment having an acid group, and the pigment dispersant is a basic polymer dispersant including units derived from &#x3b5;-caprolactone.

A liquid developer includes at least toner particles and an insulating liquid. The toner particles include a resin and a color material dispersed in the resin. 90 mass % or more of the insulating liquid is aliphatic saturated hydrocarbon having a carbon number of 11 to 16, and 20 to 60 mass % of the insulating liquid is aliphatic saturated hydrocarbon having a carbon number of 11 to 12.

The present invention provides a developer for electrophotography which is superior in property of build up of electrification and in charge stability even in environments of high temperature and high humidity or in an environment of low temperature and low humidity where it is difficult for a developer to retain its electrostatic charge performance, and which can provide an image free from fogging and decrease in density for a long term, that is, a developer for electrophotography containing composite oxide particles which include metal titanate particles containing titanium as a first metal atom and a second metal atom and containing therein 0.009 to 0.350% by weight of a third metal atom selected from the group consisting of the metal atoms belonging to Group 5A of the long form of the periodic table of elements.

Developer for electrophotography

Growing community of inventors

Sakai, Japan

Masahiro Anno