Sharp Kabushiki Kaisha Corporation

Kanto Denka Kogyo Co., Ltd.

Takanori Kamoto

Masanori Kinomoto

Hiromi Nakatsu

Tadashi Iwamatsu

Nobuyuki Yoshioka

Hiroaki Nakaya

Osamu Wada

Kiyofumi Morimoto

Ichiro Fujii

Hiroyuki Hirakawa

Takashi Hara

Yoshinori Mutoh

Kiyobumi Morimoto

Seita Suzuki

Yoshitaka Kawase

Takayuki Yamanaka

Satoru Ariyoshi

Ayae Nagaoka

Makoto Uehara

Masatomo Hayashi

Hirofumi Kanda

Yoshio Ichii

Natsuki Matsuura

Seila Suzuki

Nobuhiro Seki

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 method for producing a toner, that can produce a low temperature fixable toner in a stable manner, a toner produced by the production method, a two-component developer using the toner, a developing device and an image forming apparatus are provided. The toner is produced using an aqueous dispersion obtained by dispersing a crystalline self-dispersion polyester resin having at least one carboxyl group and containing a compound represented by the following chemical formula (1) as an alcohol component in an aqueous medium. The aqueous dispersion, a colorant particle aqueous dispersion and a wax particle aqueous dispersion are mixed to aggregate, and a non-crystalline self-dispersion polyester resin particle aqueous dispersion is further added to perform aggregation. The liquid mixture containing the aggregates is heated and washed, thereby obtaining a toner:HO&#x2014;CHCHCHCHOH&#x2003;&#x2003;(1)wherein n is an integer of from 2 to 50.

Method for producing toner, two-component developer, developing device and image forming apparatus

There are provided a carrier which enables stable charging of toner and formation of a stable, high-definition and high-quality image which has very few image defects such as a fog, as well as a developer, a developing apparatus, and an image forming apparatus. A carrier is obtained by including a carrier core and a coating layer with which a surface of the carrier core is coated, the coating layer being obtained by curing a resin composition for coating that includes a crosslinked silicone-modified acrylic resin containing a macromonomer represented by the following general formula (1). A developer is obtained by such a carrier and a toner. 

Carrier, developer, developing apparatus and image forming apparatus

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

A carrier of the present invention is used in a developer including a toner which includes at least a binder resin and an organic colorant, and the carrier has a core and a coating formed on the surface of the core, the coating including (i) a charge control agent for controlling a charge whose polarity is the same as a polarity of a charge controlled by a charge control agent included in the toner, and (ii) a conductive particles. The use of the carrier of the present invention enables: prevention of decrease in the charging amount of the toner which includes at least a binder resin and an organic colorant; and formation of a stable, high-resolution, high-quality image which has very few image defects such as a photographic fog.

Carrier, developer, development device, image forming apparatus and image forming method

A process for preparing a toner for electrostatic image development, the process comprising the steps of: (S1) mixing an aqueous pigment dispersion and an aqueous resin particle dispersion containing self-dispersible polyester resin particles as a binder resin to prepare a mixture; and (S2) adding a polyvalent metal salt as a flocculant to the mixture while stirring to form aggregates of the pigment bonded to the resin particles, wherein the self-dispersible polyester resin is prepared by reacting a carboxylic acid compound with an alcohol compound inclusive of a polyhydric alcohol, the carboxylic acid compound being one or more of a polycarboxylic acid having three or more carboxyl groups and its anhydride.

Toner for electrostatic image development and process for preparing the same

An ink composition is prepared in such a manner that a difference between a dynamic surface tension (mN/m) measured by a maximum bubble pressure method at a temperature of 24 to 26&#xb0; C. and a static surface tension (mN/m) is within a range from 0 to 7 (mN/m). The ink composition is stored in an ink tank of an ink head, and is supplied from the ink tank to an ink chamber having a discharge port, and a voltage is applied to partitions formed by a piezoelectric material to apply a pressure by the partitions to the ink composition stored in the ink chamber, whereby a liquid droplet of the ink composition is discharged from the discharge port and the liquid droplet is deposited on a recording material to record an image.

Ink composition, recording method and recorded image utilizing the same, ink set and ink head

An object of the present invention is to provide an ink composition having a high permeability as an inkjet ink and permitting high quality image printing even with a high speed. To achieve the above object, the present invention provides an ink composition including: wherein m and n each are an integer of 0-11; m+n is an integer of 9-11; x is an integer of 5-9; and y is a number between 2.5-5.

Ink composition, ink set using same, recording method, ink head and recorded image

An ink composition is prepared by incorporating water, a colorant and a polyester resin in which a polybasic carboxylic acid ingredient contains an aromatic dicarboxylic acid having a metal sulfonate group. The ink composition is stored in an ink tank of an ink head, the ink composition is supplied from the ink tank into an ink chamber having a discharge port, a voltage is applied to partition wall portions formed of a piezoelectric material, a pressure is applied to the ink composition contained in the ink chamber by the partition wall portions and liquid droplets of the ink composition are discharged from the discharge port and deposited on a recording material thereby recording images.

Ink composition, recording method and recording images using the same, as well as ink set and ink head

A method of manufacturing a toner for developing static charges in an aqueous system is provided which includes preparation step for a resin kneaded product, preparation step for the aqueous dispersion of a less water-soluble alkaline earth metal salt, preparation step for synthetic resin particles, removal step for the less water-soluble alkaline earth metal salt, and separation-cleaning-drying step. At preparation step Sfor synthetic resin, an ionic material for decomposing the less water-soluble alkaline earth metal salt is admixed with a mixture of the resin kneaded product and the aqueous dispersion of the less water-soluble alkaline earth metal salt.

Method of manufacturing a toner

An ink composition is manufactured to contain a surfactant having difference d(&#x3c3;&#x2212;&#x3b3;) which is difference between dynamic surface tension (&#x3c3;) of the solution obtained by making 0.1 wt % solution dissolved in purified water to be measured by using a maximum bubble pressure method at the bubble frequency of 10 Hz at a temperature from 24&#xb0; C. to 26&#xb0; C. and static surface tension (&#x3b3;) to be measured at a temperature from 24&#xb0; C. to 26&#xb0; C. and which satisfies 0 mN/m&#x2266;d&#x2266;15 mN/m. An image is recorded by applying a voltage to partitions made of a piezoelectric material thereby applying a pressure to the ink composition supplied from an ink tank to an ink chamber of an ink head to discharge a liquid droplet of the ink composition, and depositing the liquid droplet onto a recording material.

The present invention provides ink for inkjet recording containing ethylene glycol base ether and/or monovalent alkyl alcohol, a surfactant and a coloring agent, the ink showing the following characteristics when 2 &#x3bc;l of the ink is dropped on a piece of ordinary paper having smoothness of 100 sec or lower:

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Yamatokoriyama, Japan

Takanori Kamoto