Sharp Kabushiki Kaisha Corporation

Kanto Denka Kogyo Co., Ltd.

Osamu Wada

Tadashi Iwamatsu

Takanori Kamoto

Nobuyuki Yoshioka

Yoritaka Tsubaki

Yuya Kondo

Hiroyuki Hirakawa

Keiichi Kikawa

Takashi Hara

Takayuki Yamanaka

Yoshinori Mutoh

Ayae Nagaoka

Masatomo Hayashi

Takeshi Katoh

Tadanori Kano

Hiroki Maeda

Hirofumi Kanda

Yoshio Ichii

Natsuki Matsuura

Shoji Nakai

Nobuhiro Seki

The peak top molecular weight of the tetrahydrofuran-soluble component of the toner, as measured by gel permeation chromatography, is 4,000 or more and 6,500 or less. The tetrahydrofuran-insoluble component of the toner is 10% by weight or more and 30% by weight or less. When the endothermic peak temperature T1 in the heating process and the exothermic peak temperature T2 during the cooling process originating from the ester wax is measured using a differential scanning calorimeter, the value T1-T2 is 15° C. or more and 30° C. or less.

Toner and two-component developer

A toner contains at least a crystalline polyester resin and an amorphous linear polyester resin that uses diethylene glycol as an alcohol component, and a monoester wax and a montan ester wax as release agent components, wherein 6&#x2264;&#x3b1;&#x2264;8 and 14&#x2264;mw/&#x3b1;&#x3c;30 are satisfied, where &#x3b1; represents an amount of the crystalline polyester resin added relative to 100 parts by weight of the amorphous linear polyester resin and mw represents an amount of the montan ester wax added.

Toner, two-component developer, and method for producing toner

The toner including a crystalline polyester resin dispersed in an amorphous polyester resin obtained by polymerizing a bivalent alcohol component and a dicarboxylic component, the crystalline polyester resin containing a linear saturated aliphatic polyester unit and being dispersed by a monoester-based wax added as a detaching agent, wherein the crystalline polyester resin in the toner has a dispersion diameter of 100 nm or more and 500 nm or less, and the monoester-based wax has a dispersion diameter of 200 nm or more and 1,000 nm or less.

Toner

A two-component developer is provided. The two-component developer includes a toner containing a binder resin, a colorant and a release agent, and a resin-coated carrier composed of a carrier core material and a resin coating layer formed on a surface of the carrier core material. The toner has an exposure rate of the release agent on the toner surface of 1.00% or above and 3.07% or below. The carrier core material has an apparent density of 1.86 g/cmor more and 2.45 g/cmor less. The exposure rate of the release agent of the toner and the apparent density of the carrier core material satisfy the following formula (1):&#x2266;&#x2212;1.54+5.93&#x2003;&#x2003;(1)wherein y represents the exposure rate of the release agent of the toner, and x represents the apparent density of the carrier core material.

Two-component developer, developing device, image forming apparatus, and image forming method

The resin coated carrier is used with a toner in which an external additive having an average primary particle size of 50 nm or more is added to a toner particle, and has a carrier core and a resin coating layer on the surface of the carrier core. In the resin coated carrier, the following expression (1) is satisfied:0.5&#x2266;&#x2212;log {()/()}&#x2266;2.5&#x2003;&#x2003;(1)wherein A represents a volume resistance value (&#x3a9;/cm) of the resin coated carrier in an electric field of 1000 V/cm that is obtained by conducting a stirring test, B represents a volume resistance value (&#x3a9;/cm) of the resin coated carrier in an electric field of 1000 V/cm before the stirring test, and C represents a volume resistance value (&#x3a9;/cm) of the carrier core in an electric field of 1000 V/cm.

Resin coated carrier, two-component developer, developing device and image forming apparatus

A method for producing a low density resin-coated carrier having a small resin amount to a carrier core material and having a uniform resin coating layer formed on the carrier core material is provided. A resin-coated carrier has a carrier core material and a resin coating layer formed on the surface of the carrier core material. The carrier core material has pores and an apparent density of 1.6 g/cmto 2.0 g/cmand a remanent magnetization of 10 emu/g of less. The resin coating layer is formed by a dry process of adhering resin particles to a surface of the carrier core material and applying heat and impact force to the resin particles. A volume average particle size of the resin particles is less than 1 &#x3bc;m. A two-component developer containing the resin-coated carrier is charged in a developing device in an image forming apparatus, and an image is formed.

Method for producing resin-coated carrier, resin-coated carrier, two-component developer, developing device, image forming apparatus and image forming method

A resin coated carrier is provided that can stably charge a toner having added thereto an external additive having a large particle size over a long period of time and can prevent blocking of a developer. The resin coated carrier satisfies the following formula (1):log()&#x3e;2&#x2003;&#x2003;(1)in which Ma is a weight average molecular weight of a silicone resin having the minimum weight average molecular weight, contained in a resin coating layer, and Mb is a weight average molecular weight of a silicone resin having the maximum weight average molecular weight, and

A resin-coated carrier is provided. A resin-coated carrier includes a carrier core and a resin coating layer formed on a surface of the carrier core. The carrier core is composed of a porous material having surface fine pores formed on a surface thereof, and has an apparent density of 1.6 to 2.0 g/cm. The resin coating layer contains cross-linked fine resin particles. Additionally, the resin-coated carrier is configured such that a volume average particle size of the cross-linked fine resin particles contained in the resin coating layer and an area average diameter of the surface fine pores satisfy a predetermined relational expression.

Resin-coated carrier method of manufacturing the same, two-component developer including resin-coated carrier, developing device and image forming apparatus

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Osaka, Japan

Osamu Wada