Konica Minolta, Inc.

Yukiko Uno

Masahiro Anno

Naoki Yoshie

Satoshi Matsumoto

Chiaki Yamada

Kenji Hayashi

Masaaki Oka

Sho Kim

Keiko Momotani

Miyuki Hotta

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 in which toner particles are dispersed in an insulating liquid, the toner particles having such a core-shell structure that shell particles containing a shell resin are attached to or cover surfaces of core particles containing a core resin, the core resin having an acid group and an acid dissociation constant not smaller than 2.90 and not greater than 8.00, and a method for manufacturing the same are provided. The toner particles can have a volume average particle size not smaller than 0.01 &#x3bc;m and not greater than 100 &#x3bc;m and a coefficient of variation of volume distribution not lower than 1% and not higher than 100%. This liquid developer has excellent fixability which allows adaptation to various recording materials, can be fixed in a wide temperature range, and is extremely low in deterioration in fixability during storage.

Liquid developer and method for manufacturing the same

A liquid developer set of the present invention includes a first liquid developer including an insulating liquid and first toner particles and a second liquid developer including an insulating liquid and second toner particles, the first toner particles include carbon black and a first resin, the second toner particles include a coloring agent other than carbon black and a second resin, without including carbon black, the first resin and the second resin each include a hydrocarbon long chain which is a hydrocarbon group having a carbon number of 8 to 30, and a mass ratio of the hydrocarbon long chain to the first toner particles is higher than a mass ratio of the hydrocarbon long chain to the second toner particles.

Liquid developer set

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. Heat of fusion with differential scanning calorimetry of the second resin satisfies Equations (1) to (2) below. In Equations (1) to (2) below, H1 and H2 represent heats of fusion (J/g) at initial temperature increase and second temperature increase with differential scanning calorimetry of the second resin, respectively.5&#x2266;1&#x2266;70&#x2003;&#x2003;Equation (1)0.2&#x2266;2/1&#x2266;1.0&#x2003;&#x2003;Equation (2)

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.).

Toner particles contained in a liquid developer 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 second resin satisfies Equations (1) to (2) below. In Equations (1) to (2) below, 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;50000&#x2003;&#x2003;Equation (2)

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.

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Kyoto, Japan

Yukiko Uno