Chemically Or Physically Identified Binder Or Coating Resin For Magnetic Carrier Patents (Class 430/111.35)
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Patent number: 7759040Abstract: A cleaner-less image forming method includes forming an electrostatic latent image on a electrostatic latent image carrying member; developing the electrostatic latent image with a developer comprising a toner and a carrier to form a toner image; and transferring the toner image. The carrier has a median of an arithmetic average height distribution of from 0.45 to 0.65 ?m, and the toner includes an external additive and has an average circularity of 0.975 or more.Type: GrantFiled: October 13, 2004Date of Patent: July 20, 2010Assignee: Fuji Xerox Co., Ltd.Inventors: Noriyuki Mizutani, Yuusaku Shibuya, Masanobu Ninomiya, Toshiyuki Yano
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Publication number: 20100136473Abstract: A magnetic carrier which has magnetic carrier particles each having at least porous magnetic core particles and a resin, in which, in a backscattered electron image of the magnetic carrier particles, photographed with a scanning electron microscope as taken at an accelerating voltage of 2.0 kV, magnetic carrier particles having area proportion S1 found from a specific expression (1) of from 0.5 area % or more to 8.0 area % or less are in a proportion of 80% by number or more in the magnetic carrier, an average proportion Av1 of the total area of portions having a high luminance which come from a metal oxide on the magnetic carrier particles to the total projected area of the magnetic carrier particles is from 0.5 area % or more to 8.0 area % or less, and an average proportion Av2 found from a specific expression (2) is 10.0 area % or less.Type: ApplicationFiled: January 21, 2010Publication date: June 3, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Koh Ishigami, Hiroyuki Fujikawa, Kunihiko Nakamura, Nozomu Komatsu, Chika Inoue, Tomoko Endo, Yoshinobu Baba, Takayuki Itakura
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Publication number: 20100119967Abstract: A magnetic carrier and a two-component developer are provided which have remedied blank areas, fog after leaving, carrier sticking during running, and image density variations before and after running. The magnetic carrier has magnetic carrier particles having at least porous magnetic core particles and a resin. The magnetic carrier particles satisfying the specific conditions (a), (b) and (c) where, in a reflected electron image of cross sections of the magnetic carrier particles as photographed with a scanning electron microscope, straight lines that divide a cross section of a magnetic carrier particle into 72 at intervals of 5° are drawn from a reference point of the cross section thereof toward the surface of the magnetic carrier particle; the magnetic carrier particles being contained in an amount of 60% by number or more.Type: ApplicationFiled: January 21, 2010Publication date: May 13, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Chika Inoue, Hiroyuki Fujikawa, Koh Ishigami, Kunihiko Nakamura, Nozomu Komatsu, Tomoko Endo, Yoshinobu Baba, Takayuki Itakura
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Patent number: 7687216Abstract: A two-component developer is provided in which the reduction of the hot offset occurrence temperature due to detachment of the coating layer, image density insufficiency, image fogging and toner scattering and the like can be suppressed. In the two-component developer including a toner and a carrier, the content of acrylic resin in a coating layer of the carrier is in a range from 5 to 50% by weight based on the total amount of the coating layer, and the dielectric loss (tan ?) is in the range from 4.0×10?3 to 15.0×10?3. By using the two-component developer, the reduction of the hot offset occurrence temperature in a fixing apparatus can be prevented. Further, image density insufficiency, image fogging and toner scattering and the like can be suppressed, with a result that images having high quality and sufficient image density can be obtained.Type: GrantFiled: June 17, 2005Date of Patent: March 30, 2010Assignee: Sharp Kabushiki KaishaInventors: Toshiharu Kataoka, Masahiro Sakai
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Patent number: 7682764Abstract: A resin coated carrier for electrophotography and a two-component developer for electrophotography made therefrom, in which electrostatic charge giving ability to toner is high, anti-spent property is superior, charging property is stable even if a large number sheets are continuously printed, initial electrostatic charge increasing ability and electrostatic charge maintaining ability after leaving are also superior, and fogging at supplying toner and fogging after leaving are not generated. In a resin coated carrier for electrophotography comprising a coating material and a core material, in which the coating material covers the surface of the core material, the coating material contains a resin component and a conductive agent, the core material is ferrite, and electric resistance of the carrier at an applied voltage of 100 V set to be 1.0×103 to 1.0×106 ?·cm, or breakdown voltage is set to be 120 to 280 V.Type: GrantFiled: April 19, 2005Date of Patent: March 23, 2010Assignee: Tomoegawa Paper Co., LtdInventors: Akira Fujiwara, Yoshiaki Harada
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Publication number: 20100028796Abstract: A magnetic carrier and two-component developer are provided alleviating coarse images, fogging when printing is done after a copier body is left standing for one week in a high temperature and high humidity environment and carrier adhesion after extensive operation in a low image ratio. The magnetic carrier includes magnetic carrier particles including porous magnetic core particles and a resin, wherein in a mercury intrusion method applied to the porous magnetic core particles, a pore diameter in which a differential pore volume in the specific pore diameter range becomes maximum is in a specific range, and when the maximum value of a differential pore volume in the specific pore diameter range is defined as P1 and the maximum value of a differential pore volume in the specific pore diameter range is defined as P2, P1 is in a specific range and the ratio P2/P1 is in a specific range.Type: ApplicationFiled: August 4, 2009Publication date: February 4, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Kunihiko Nakamura, Hiroyuki Fujikawa, Koh Ishigami, Nozomu Komatsu, Chika Inoue, Tomoko Endo, Yoshinobu Baba, Takayuki Itakura
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Patent number: 7632620Abstract: A carrier comprised of a core, and thereover a polymer coating containing a first polymer and a silicone resin, and which resin possesses an average diameter of from about 300 to about 3,000 nanometers.Type: GrantFiled: January 28, 2005Date of Patent: December 15, 2009Assignee: Xerox CorporationInventors: Brian S. Giannetto, Thomas J. Budny, Brian E. Moore, Zhaoyi M. Masucci, Samir Kumar, Bernard A. Kelly, Lloyd D. Spencer
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Patent number: 7622235Abstract: Coated carrier particles are provided for use in developer compositions for electrophotographic imaging. The coated carrier particles include a carrier core and a resin coating that includes first and second polymer components. The coated carrier particles exhibit stable triboelectric charging during aging, decreased coating hardness, higher coating coverage, and an improved resilience to toner impaction.Type: GrantFiled: August 29, 2008Date of Patent: November 24, 2009Assignee: Xerox CorporationInventors: Deepak R. Maniar, Thomas C. Dombroski, Victor Berko-Boateng, Christopher M. Pattison, Angela Schnuerch
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Patent number: 7601475Abstract: A two-component developing agent containing a carrier which can maintain a charge-imparting property to a toner at a high level for a long period of time, does not generate flying of the carrier and can correspond to an image forming apparatus of present day having a long operation life and can form a high-quality image having high image density and sharpness, is provided. In the two-component developing agent containing a carrier in which a resin coating layer is formed on a surface of a core material, and a toner, in which an X-ray intensity of an alumina particle by a fluorescent X-ray analysis, the amount of the alumina particle to be used to the resin coating layer is adjusted such that it comes to be smaller than the X-ray intensity by the fluorescent X-ray analysis of a metal contained in a largest amount in the core material.Type: GrantFiled: September 12, 2006Date of Patent: October 13, 2009Assignee: Sharp Kabushiki KaishaInventors: Takeshi Katoh, Toshihisa Ishida, Yoshinori Urata, Kazuya Korematu, Takeshi Takayama, Mitsuhiro Hasegawa
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Patent number: 7595138Abstract: A toner of the present invention is a toner comprising an additive and a toner matrix that contains a binder resin, a colorant, and a wax, in which the additive contains an inorganic micropowder to whose surface polysiloxane and at least one selected from fatty acids and derivatives thereof are adhered. Thus, the present invention provides the toner, a two-component developer, and an image forming method with which oil-less fixing is possible without the use of an oil on a fixing roller. Furthermore, the present invention provides the two-component developer that causes less carrier deterioration by toner-spent even when used in combination with a toner containing wax or another such release agent and thus the developer has good durability. In addition, the present invention provides the toner, the two-component developer, and the image forming method with which partial transfer defects are reduced and high transfer efficiency can be obtained.Type: GrantFiled: November 27, 2003Date of Patent: September 29, 2009Assignee: Panasonic CorporationInventor: Yasuhito Yuasa
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Patent number: 7592115Abstract: A carrier for electrostatic latent image developer, including a core material and at least two or more resin-coated layers formed on the surface of the core material, wherein the resin-coated layers include a siloxane bond-containing coating resin containing an organic metal compound and a conductive material, the metal contained in the organic metal compound in the innermost resin-coated layer has an ionization potential of less than 7 eV, and the metal contained in the organic metal compound in the outermost resin-coated layer has an ionization potential of 7 eV or more.Type: GrantFiled: October 14, 2005Date of Patent: September 22, 2009Assignee: Fuji Xerox Co., Ltd.Inventors: Yasushige Nakamura, Sadaaki Yoshida
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Patent number: 7592116Abstract: The object of the present invention is to provide a carrier for electrophotography which includes a core material and a coating layer comprising particles on a surface of the core material, in which the carrier for electrophotography comprises indium (In) in an amount of 0.0001% by mass to 0.5% by mass. The present invention also provides a developer using the carrier, a developer container, an image forming method, an image forming apparatus, and a process cartridge in each of which the carrier is used.Type: GrantFiled: November 10, 2005Date of Patent: September 22, 2009Assignee: Ricoh Company, Ltd.Inventors: Kousuke Suzuki, Tomio Kondou, Shinichiro Yagi, Hitoshi Iwatsuki
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Publication number: 20090233202Abstract: A two component developer comprising a toner and a carrier, wherein the toner includes: colored particles; and external additive particles comprising a complex oxide incorporating silicon atoms and at least one of titanium atoms and aluminum atoms, and a surface existing ratio of the silicon atoms (R2) in a surface of the external additive particles being larger than an average existing ratio of the silicon atoms (R1) in an entirety of the external additive particles, and carrier particles comprise magnetic material powder dispersed in a phenol-formaldehyde resin, and have an average of the shape coefficient SF-1 of 1.0 to 12 and an average of the shape coefficient SF-2 of 1.1 to 2.5, and a volume based median diameter of from 10 to 100 ?m.Type: ApplicationFiled: March 4, 2009Publication date: September 17, 2009Applicant: KONICA MINOLTA BUSINESS TECHNOLOGIES, INC.Inventors: Masahiro ANNO, Masahiko NAKAMURA, Tsuyoshi UCHIDA, Kenichi ONAKA, Junya ONISHI, Naoya TONEGAWA
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Patent number: 7585605Abstract: The invention discloses an electrostatic latent image developer including a toner and a carrier. The carrier has cores and a coating resin including an electrically conductive material on the surface of each of the cores. The coating resin has an inner portion and an outermost portion, and the outermost portion is made of a cross-linked resin. The content of the electrically conductive material in the outermost portion is lower than that in the inner portion. The toner has toner mother particles, and, on the surface of each of the toner mother particles, inorganic particles and resin particles, and the resin particles are made of a non-cross-linking resin.Type: GrantFiled: April 19, 2006Date of Patent: September 8, 2009Assignee: Fuji Xerox Co., Ltd.Inventor: Yasushige Nakamura
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Publication number: 20090202935Abstract: A carrier including magnetic core particles and a coating layer, wherein the coating layer is formed by applying a coating liquid containing at least colloidal silica, a condensate of alkoxysilane represented by General Formula (1) and a solvent onto the core particles; an amount of colloidal silica contained in the coating layer is less than 60% by mass; and a ratio (h/Dw) of a thickness (h) of the coating layer to a weight average particle diameter (Dw) of the carrier is more than 0.01, wherein the carrier is used in a two-component developer together with a toner produced through aqueous granulation and containing at least a colorant, a binder resin and a releasing agent, and wherein an amount of the releasing agent present in a region from a surface of the toner to a depth of 0.3 ?m is less than 4% by mass as measured through FTIR-ATR spectroscopy.Type: ApplicationFiled: February 5, 2009Publication date: August 13, 2009Inventors: Yoshihiro Moriya, Keishi Taniguchi, Akihiro Kotsugai, Ryota Inoue, Shingo Sakashita
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Patent number: 7570904Abstract: In the image forming apparatus by: visualizing an electrostatic latent image formed on an electrostatic charge carrying member; transferring a toner image, which is thus visualized, to a recording medium, or to a recording medium through an intermediate transfer material; and fixing the toner image, which is thus transferred to the recording medium, to obtain a recorded image, the toner includes at least a fixing resin, a colorant, a releasing agent, and an external additive, the toner has an average particle diameter in a range of from 4 to 12 ?m and including no particle having a diameter of 45 ?m or more, a ratio of a toner adhesion amount in a character part to a toner adhesion amount in a solid image part upon printing is more than 0.5 and less than 4, and the toner adhesion amount in a character part is 1.6 mg/cm2 or less.Type: GrantFiled: May 26, 2005Date of Patent: August 4, 2009Assignee: Ricoh Printing Systems, Ltd.Inventors: Shigenori Yaguchi, Junji Kobayashi, Hirobumi Ouchi, Tomonari Hokkyo
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Patent number: 7566519Abstract: A carrier for an electrophotographic developer which is used as an electrophotographic developer in a mixture with a toner and which secures sufficiently the image density and can maintain high-quality images for a long period, and an electrophotographic developer using the carrier, are provided. A resin-filled ferrite carrier for electrophotographic developer obtained by filling, with a resin, avoid of a porous ferrite core whose void continues from the surface to reach the interior of the core, the carrier comprising a plurality of three-dimensional laminate structures in which resin layers and ferrite layers are alternately present, and an electrophotographic developer including the carrier and a toner, are employed.Type: GrantFiled: August 25, 2006Date of Patent: July 28, 2009Assignee: Powdertech Co., Ltd.Inventors: Hiromichi Kobayashi, Tsuyoshi Itagoshi, Tomoyuki Suwa, Toshio Honjo
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Publication number: 20090169263Abstract: Carrier particles for a developer used in an image forming apparatus, in which the carrier particles contain a core material containing magnetic particles, and a coating layer formed on a surface of the core material, and the coating layer contains diamond fine particles or diamond-like carbon exposed on a surface of the coating layer.Type: ApplicationFiled: December 22, 2008Publication date: July 2, 2009Applicants: KABUSHIKI KAISHA TOSHIBA, TOSHIBA TEC KABUSHIKI KAISHAInventors: Takeshi Watanabe, Mitsuaki Kouyama
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Patent number: 7553598Abstract: A carrier contains a core; and a cover layer located overlying the core, wherein the cover layer comprises a binder resin, a first particulate material and a second particulate material, wherein the following relationships are satisfied: 1<(D1/h)<10, and 0.001<(D2/h)<1, wherein D1(?m) represents a volume average particle diameter of the first particulate material, D2(?m) represents a volume average particle diameter of the second particulate material, and h (?m) represents a thickness of the cover layer, and wherein the second particulate material has a volume resistivity of not greater than 1.0×1012 ?·cm.Type: GrantFiled: March 20, 2006Date of Patent: June 30, 2009Assignee: Ricoh Company, LimitedInventors: Kousuke Suzuki, Tomio Kondoh, Shinichiro Yagi, Hitoshi Iwatsuki
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Patent number: 7553597Abstract: A carrier core material containing at least one metal oxide (MLO) having a melting point of not higher than 1000° C. and at least one metal oxide (MHO) having a melting point of not lower than 1800° C., wherein the metal (MH) for constituting the metal oxide (MHO) has an electrical resistivity of not less than 10?5 ?·cm. Also disclosed is a two-component developing agent comprising a coated carrier, which comprises the carrier core material coated with a resin, and toner particles. Further disclosed is an image forming method comprising developing an electrostatic latent image formed on a photosensitive member with the two-component developing agent using an alternating electric field. The carrier core material and the coated carrier have high magnetization and are free from occurrence of leakage of electric charge over a wide range of electric field from low electric field to high electric field. According to the two-component developing agent, an excellent image can be formed.Type: GrantFiled: February 6, 2004Date of Patent: June 30, 2009Assignee: Powdertech Co., Ltd.Inventors: Hiromichi Kobayashi, Issei Shinmura, Tsuyoshi Itagoshi, Yuji Sato
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Publication number: 20090092920Abstract: The present invention is to provide a carrier and a developer, which have fewer occurrences of carrier adhesion and background smear, excellent granularity and longer durability. The carrier comprises the core material particles having magnetism and resin coating layer covering the core material particles, and wherein the weight average particle diameters is in the range of 22 m to 32 m, the proportion of the weight average particle diameters relative to the number average particle diameter is in the range of 1.00 to 1.20, the content of particles having a diameter of 20 m or smaller is 7% by mass, the content of carrier particles having a diameter of 36 m or smaller is in the range of 90% by mass to 100% by mass, and the proportion of the particle density of the core material particles is in the range of 85% to 100% of the true density of the core material particles.Type: ApplicationFiled: March 6, 2007Publication date: April 9, 2009Inventors: Masashi Nagayama, Kimitoshi Yamaguchi, Naoki Imahashi
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Publication number: 20090087771Abstract: An objective is to provide an electrophotographic carrier as a resin coating type carrier containing a conductive particle in a resin coating layer, which inhibits an edge effect via appropriately sufficient action as a developing electrode for a long duration, and acquires high fine line reproduction. Disclosed is an electrophotographic carrier possessing a surface of a magnetic material particle and provided thereon a resin coating layer containing a conductive particle, wherein a cross section of the resin coating layer, photographed with a transmission electron microscope has an average porosity ratio of 1-20%, and further disclosed is the electrophotographic carrier, wherein the resin coating layer comprises an acrylic resin.Type: ApplicationFiled: August 22, 2008Publication date: April 2, 2009Applicant: KONICA MINOLTA BUSINESS TECHNOLOGIES, INC.Inventors: Hidemasa SAWADA, Kenji YAMANE
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Patent number: 7510813Abstract: To provide a resin-coated carrier for an electrophotographic developer capable of providing an image with excellent image quality; and a two-component developer and a replenishing developer each of which contains the resin-coated carrier as a constituent.Type: GrantFiled: June 24, 2005Date of Patent: March 31, 2009Assignee: Canon Kabushiki KaishaInventors: Tetsuya Yano, Takashi Kenmoku, Chieko Mihara, Tatsuki Fukui, Ako Kusakari, Norikazu Fujimoto
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Patent number: 7476483Abstract: A carrier for electrophotographic developer comprises a resin carrier core comprising a binder resin and magnetic powder dispersed in the binder resin, and a coating layer comprising a coating resin on a surface of the core, the binder resin being a silicone resin obtained by curing of a polysiloxane compound (A) having an epoxy group and a polysiloxane compound (B) having a group capable of reacting with the epoxy group, due to a ring-opening addition reaction; the binder resin containing a functional group which is an epoxy group and/or a group capable of reacting with an epoxy group; the coating resin containing a functional group capable of reacting with the functional group of the binder resin; the functional group of the coating resin and the function group of the binder resin forming a chemical bond.Type: GrantFiled: December 7, 2005Date of Patent: January 13, 2009Assignees: Mitsui Mining and Smelting Co., Ltd., Powdertech Co., Ltd.Inventors: Yoichi Kamikoriyama, Kenji Suzuoka, Takashi Nakashima, Kazuya Kinoshita, Yuji Sato, Hiromichi Kobayashi, Takeshi Gondo, Takashi Hikichi
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Patent number: 7470497Abstract: The present invention is a carrier for electrophotography in which a surface of at least a core material is coated with a resin, in which the coating resin contains a fluorine modified silicone resin and an aminosilane coupling agent, and in which the carrier charges a toner negatively. Consequently, a carrier with a high durability and a long lifetime for electrophotography is provided, in which the charge amount does not decrease at high temperature or high humidity nor extremely increase at low temperature or low humidity, in which a deterioration of a developing agent caused by stripping of a coating layer is prevented, and in which a deterioration caused by formation of spent toner of a toner is not caused.Type: GrantFiled: September 30, 2003Date of Patent: December 30, 2008Assignee: Panasonic CorporationInventors: Yasuhito Yuasa, Kiminori Umeda, Tetsuya Uemura, Tsuyoshi Itagoshi
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Patent number: 7468233Abstract: Electro-photographic images having high picture quality and low carrier adhesion can be obtained using a two-component developer containing a carrier containing (A) a carrier containing a core containing a magnetic material, the core being coated with at least one resin layer; and (B) a toner; wherein the carrier has a weight average particle diameter Dw of 22-32 ?m; wherein a content of carrier particles having a diameter smaller than 20 ?m is 0-7% by weight based on the weight of the carrier; wherein a content of carrier particles having a diameter smaller than 36 ?m is 90-100% by weight based on the weight of the carrier; wherein a weight average particle diameter Dw of the toner is 2-7 ?m; and wherein a ratio Dw/Dn of the weight average particle diameter of the toner to the number average particle diameter of the toner is 1.00-1.25.Type: GrantFiled: September 12, 2005Date of Patent: December 23, 2008Assignee: Ricoh Company, Ltd.Inventors: Masashi Nagayama, Kimitoshi Yamaguchi, Naoki Imahashi
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Patent number: 7455945Abstract: A carrier excellent in durability and environmental stability and a two-component developing agent is provided. In the carrier, a core material is coated with a resin, and the coating resin is formed on the core material such that the coating resin comes to be in an amount of 5% by weight to 20% by weight on the basis of a weight of the core material, thereby enhancing durability. Further, the coating resin contains fine particles of titanium oxide, thereby enhancing environmental stability.Type: GrantFiled: June 6, 2005Date of Patent: November 25, 2008Assignee: Sharp Kabushiki KaishaInventors: Takeshi Katoh, Yoshinori Urata, Kazuya Korematu
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Patent number: 7455946Abstract: A two-component developing agent retained on the periphery surface of a magnetic roller 11 and a development roller 12 are brought in contact with each other, the nonmagnetic toner in the two-component developing agent is electrostatically adhered to the periphery surface of the development roller 12, and the nonmagnetic toner on the development roller 12 is sprayed on the periphery surface of a photosensitive drum 13, thereby causing an image of an electrostatic latent image to appear on the photosensitive drum 13 as a toner image. The two-component developing agent for an image forming device thus configured comprises a nonmagnetic toner comprising color particles, and a magnetic carrier, wherein the magnetic carrier has a resin coating layer on the magnetic particle surface, and the critical surface tension of this resin coating layer is 25 dyn/cm or less.Type: GrantFiled: October 27, 2005Date of Patent: November 25, 2008Assignee: Kyocera Mita CorporationInventors: Naruo Yabe, Kouzou Teramoto, Norio Kubo, Takeo Mizobe
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Patent number: 7452650Abstract: A carrier comprised of a core and a polymer generated from a mixture of two latexes, and wherein the first latex enables a polymer with a high molecular weight, and the second latex enables a polymer with a low molecular weight, and wherein high represents a weight average molecular weight of from about 1,000,000 to about 8,000,000, and said low represents a weight average molecular weight of from about 500,000 to about 750,000.Type: GrantFiled: January 26, 2005Date of Patent: November 18, 2008Assignee: Xerox CorporationInventors: Robert D. Bayley, Grazyna E. Kmiecik-Lawrynowicz, Maura A. Sweeney
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Patent number: 7435522Abstract: Coated carrier particles are provided for use in developer compositions for electrophotographic imaging. The coated carrier particles include a carrier core and a resin coating that includes first and second polymer components. The coated carrier particles exhibit stable triboelectric charging during aging, decreased coating hardness, higher coating coverage, and an improved resilience to toner impaction.Type: GrantFiled: March 31, 2005Date of Patent: October 14, 2008Assignee: Xerox CorporationInventors: Deepak R. Maniar, Thomas C. Dombroski, Victor Berko-Boateng, Christopher M. Pattison, Angela Schnuerch
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Patent number: 7432031Abstract: A toner for electrostatic charge developing prepared by a production method including aggregating one or more kind of particles in a raw material dispersion including the particles to form aggregated particles, and coalescing the aggregated particles by heating. At least one kind of the particles is resin particles including an amorphous polyester resin synthesized by copolymerizing one or more polyvalent carboxylic acids and two or more polyhydric alcohols; at least one of the polyvalent carboxylic acids is polyvalent carboxylic acid having a sulfonic acid group; two of the polyhydric alcohols are an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A; and the following equation is satisfied: 10/90?BPA(EO)/BPA(PO)?90/10.Type: GrantFiled: August 11, 2005Date of Patent: October 7, 2008Assignee: Fuji Xerox Co., Ltd.Inventors: Noriyuki Mizutani, Hideo Maehata, Hirokazu Hamano, Hiroyuki Tanaka, Soichiro Kitagawa, Moegi Iguchi
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Patent number: 7419755Abstract: Carrier particles comprise a core and a polymer coating that comprises a mixture of polymethyl methacrlyate (PMMA) and melamine. The coating compositions comprise from about 60 to about 80 percent by weight of PMMA and from about 20 to about 40 percent by weight of melamine. The carriers may be combined with a toner to provide a developer suitable for use in an electrostatographic process. Carriers comprising the PMMA/melamine coatings exhibit increased triboelectric charging, a more conductive carrier, and also contribute to reducing toner cohesion.Type: GrantFiled: June 22, 2005Date of Patent: September 2, 2008Assignee: Xerox CorporationInventors: Deepak R. Maniar, Thomas C. Dombroski, Christopher M. Pattison, Bernard A. Kelly
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Patent number: 7399568Abstract: There is provided a resin-coated carrier with a coating layer attached to the surface of a core material in a stable manner, the electrophotographic carrier which can provide an image with excellent quality.Type: GrantFiled: June 24, 2005Date of Patent: July 15, 2008Assignee: Canon Kabushiki KaishaInventors: Tatsuki Fukui, Tetsuya Yano, Takashi Kenmoku, Chieko Mihara, Ako Kusakari, Norikazu Fujimoto
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Patent number: 7393622Abstract: A durable two-component developing agent for electrophotography is provided that can not only suppress scattering of a toner into an inside of an apparatus but also obtain a high image density and can stably obtain a high-quality image even in use for a long period of time. The two-component developing agent for electrophotography includes a toner, and a carrier. The carrier contains a core material and a coating layer formed on a surface thereof. The coating layer is a silicone resin coating layer containing dendritic titanium oxide. Therefore, it is possible to not only suppress scattering of the toner but also obtain a sufficient image density and to form a high-quality image without reducing the image density even in use for a long period of time.Type: GrantFiled: June 2, 2005Date of Patent: July 1, 2008Assignee: Sharp Kabushiki KaishaInventors: Yoshinori Urata, Takeshi Katoh
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Patent number: 7384719Abstract: A carrier composition, including a particulate magnetic material; and a layer located on a surface of the particulate magnetic material, wherein the layer is formed by heating a mixture containing a metal alkoxide; a resin having a hydroxyl group reacting with the metal alkoxide; and a particulate inorganic material.Type: GrantFiled: March 2, 2005Date of Patent: June 10, 2008Assignee: Ricoh Company Ltd.Inventors: Masahide Yamashita, Tomio Kondou, Kousuke Suzuki
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Patent number: 7381513Abstract: A carrier containing a core material and a resin coating layer located overlying the surface of the core material. The resin coating layer contains resin and electroconductive particles having an oil absorption amount of from 10 to 300 ml/100 g. The electroconductive particle contains a base material particle and an electroconductive coating layer located overlying the surface of the base material particle. The electroconductive coating layer contains an underlayer containing tin dioxide and an upper layer containing indium oxide and tin dioxide, located overlying the underlayer.Type: GrantFiled: July 27, 2005Date of Patent: June 3, 2008Assignee: Ricoh Company, Ltd.Inventors: Kohsuke Suzuki, Tomio Kondoh, Shinichiro Yagi, Hitoshi Iwatsuki
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Patent number: 7374849Abstract: A carrier comprised of a core, and thereover a polymer coating containing antimony tin oxide with an average diameter of from about 5 to about 90 nanometers.Type: GrantFiled: January 26, 2005Date of Patent: May 20, 2008Assignee: Xerox CorporationInventors: Vladislav Skorokhod, Maria N V. McDougall, Richard P N. Veregin, Cuong Vong, Jackie B. Parker
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Patent number: 7374850Abstract: Carrier comprised of a core, a polymer coating, and wherein said coating contains a mixture of an alkali metal lauryl sulfate and a conductive component.Type: GrantFiled: April 29, 2005Date of Patent: May 20, 2008Assignee: Xerox CorporationInventors: Christopher M. Pattison, Thomas C. Dombroski, Deepak R. Maniar
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Publication number: 20080085460Abstract: A toner that when the complex elastic modulus measured at an angular frequency of 6.28 rad/sec., and a strain amount of 0.3% is 1×106 Pa or more and 1×108 Pa or less, the tangent loss is 0.5 or more and 1.8 or less.Type: ApplicationFiled: April 20, 2007Publication date: April 10, 2008Applicant: FUJI XEROX CO., LTD.Inventors: Masanobu Ninomiya, Toyofumi Inoue, Masataka Kuribayashi, Masashi Ikeda, Takafumi Koide
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Publication number: 20080081278Abstract: An image forming apparatus, including a latent image-holding member, a developing unit, a transfer unit, a cleaning unit, and a recycling unit, wherein the developer includes a toner having an external-additive adhesiveness index SA in the range of approximately 50% to approximately 95% and: a carrier containing magnetic particles and a coating layer coating the surface of the magnetic particles and having a total energy of approximately 1,420 to approximately 2,920 mJ; or a carrier containing magnetic powder-dispersed particles and a coating layer coating the surface of the magnetic powder-dispersed particles and having a total energy of, approximately 890 to approximately 1,390 mJ.Type: ApplicationFiled: May 30, 2007Publication date: April 3, 2008Applicant: FUJI XEROX CO., LTD.Inventors: Akira Matsumoto, Akihiro Iizuka, Fusako Kiyono
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Patent number: 7344812Abstract: A developer for developing an electrostatic latent image, including a carrier which includes core particles, and a surface layer surrounding each of the core particles and containing an acrylic resin binder; and a toner which includes toner particles and an external additive of inorganic or organic fine particles present on each of the toner particles. Each of the toner particles comprises a colorant, a matrix of a first resin, and a plurality of domains of a second resin dispersed in the matrix and containing a wax. The first resin is substantially free of tetrahydrofuran insoluble matters and has a weight average molecular weight of 3,000 to 90,000.Type: GrantFiled: March 20, 2003Date of Patent: March 18, 2008Assignee: Ricoh Company, Ltd.Inventors: Kohsuke Suzuki, Satoshi Mochizuki, Tomio Kondou, Masahide Yamashita, Tomomi Tamura, Takayuki Koike
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Patent number: 7340202Abstract: An image forming apparatus and process cartridge that achieves extended operating life of a two-component developer without generating such problems as toner scattering, etc. either in the initial period or over time. The gap between the image support member and the developer support member is set to 0.3±0.1 mm. A substance having a resin cover layer on the surface of a core material is used as the carrier. The resin cover layer provides a conductive covering layer having a tin dioxide layer on the surface of base particles and an indium oxide layer, and contains conductive particles formed such that the oil adsorption is 10 to 300 mL/100 g. A substance that provides a bonding resin including a hybrid resin having vinyl polymers and polyester polymers is used as the toner. The amount of hybrid resin contained in relation to the amount of releasing agent is set to the range of 0.5 to 3.Type: GrantFiled: November 4, 2005Date of Patent: March 4, 2008Assignee: Ricoh Company, Ltd.Inventors: Satoru Miyamoto, Makoto Yasuda
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Patent number: 7320852Abstract: A carrier for use with a toner as a two-component type developer for developing an electrostatic image, comprising spherical magnetic core particles, and a resin layer covering each of said core particles and containing at least two resistance controlling materials having different specific resistances, wherein each of the resistance controlling materials is in the form of particles having a number average particle diameter of no more than 1/10 of a number average particle diameter of the toner.Type: GrantFiled: March 21, 2003Date of Patent: January 22, 2008Assignee: Ricoh Company, Ltd.Inventors: Akihiro Kotsugai, Kimitoshi Yamaguchi, Naoki Imahashi, Hiroaki Takahashi
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Publication number: 20080014514Abstract: A developer which contains a toner manufactured in a wet method and a carrier, forms an image which has enhanced image density, image reproducibility, etc., and prevents image defects such as fog from being generated. As the toner manufactured in the wet method, there is used a toner which is obtained in a production method including an admixture preparing step (S1), an aggregate forming step (S2), a particle forming step (S3), and a cleaning step (S4) and which contains pigment and self-dispersible resin containing self-dispersible polyester having an acid number of 1 mgKOH/g to 30 mgKOH/g. As the carrier, there is used a carrier composed of a core material and a coating layer which contains conductive particles formed on a surface of the core material, preferably, a coating layer which is made of a silicone resin composition containing silicone resin and conductive particles.Type: ApplicationFiled: July 12, 2007Publication date: January 17, 2008Applicant: SHARP KABUSHIKI KAISHAInventor: Takanori Kamoto
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Electrostatic latent image carrier, electrostatic latent image developer and image forming apparatus
Publication number: 20070243479Abstract: An electrostatic latent image carrier having core particles and a resin coating layer that coats the surface of the core particles, wherein the surface roughness of the core particles exhibits a surface roughness Sm that satisfies the expression Sm?2.0 ?m and a surface roughness Ra (compliant with JIS B0601) that satisfies the expression Ra?0.1 ?m, the surface roughness Ra (compliant with JIS B0601) of the electrostatic latent image carrier satisfies the expression Ra?0.5 ?m, and a sphericity of the electrostatic latent image carrier is 0.975 or higher. In addition, an electrostatic latent image developer that includes a toner and a carrier, wherein the carrier is the electrostatic latent image carrier described above.Type: ApplicationFiled: October 16, 2006Publication date: October 18, 2007Applicant: FUJI XEROX CO., LTD.Inventors: Koutarou Yoshihara, Masahiro Takagi, Satoshi Inoue, Yosuke Tsurumi, Moegi Iguchi -
Patent number: 7279262Abstract: A magnetic carrier composed of carrier particles is provided in which each carrier particle has a carrier core including magnetic fine particles and a binder resin with the carrier core surface being coated with a coat material containing a coat resin. In the magnetic carrier, Fatom/Catom and (Fatom/Catom)/(Fcalc/Ccalc) are respectively in specific ranges, wherein Fatom and Catom represent respectively a fluorine element abundance ratio and a carbon element abundance ratio at the magnetic carrier particle surface, and Fcalc and Ccalc represent respectively a fluorine element abundance ratio and a carbon element abundance ratio which are calculable from the molecular structure of the coat resin. In addition, a two-component developer is provoded including the magnetic carrier and a toner having a specific contact angle against water.Type: GrantFiled: November 16, 2004Date of Patent: October 9, 2007Assignee: Canon Kabushiki KaishaInventors: Hiroyuki Fujikawa, Takayuki Itakura, Takakuni Kobori, Koh Ishigami, Nobuyoshi Sugahara, Yoshinobu Baba, Hirohide Tanikawa
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Publication number: 20070231732Abstract: There are adopted an electrophotographic resin-coated ferrite carrier having a carrier core coated with a resin, wherein a product of an apparent density ? (g/cm3), average particle size d (?m) and BET specific surface area S (m2/g) of the carrier core satisfies the following condition, a method for producing the same, and an electrophotographic developer. 4.5??×d×S?8.Type: ApplicationFiled: March 30, 2007Publication date: October 4, 2007Applicant: Powdertech Co., Ltd.Inventors: Issei Shinmura, Kanao Kayamoto
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Patent number: 7272347Abstract: A carrier including a magnetic core material and a layer located on a surface of the magnetic core material, wherein the carrier satisfies the following relationships (1) to (3): 0.90?(?a/?b)<1.00 (1); 200?(?b·?c)?400 (2); 10?(?b/?c)?20 (3), wherein ?b represents a magnetization of the carrier at 1,000 Oe, ?a represents a magnetization of the carrier after frictionized with a cylindrical sleeve under a specific condition and ?c represents a true specific gravity of the carrier, wherein the carrier has a weight-average particle diameter of about 25 to about 65 ?m and includes carrier particles having a weight-average particle diameter not greater than about 12 ?m in an amount of not greater than about 0.3% by weight, wherein a ratio between the weight-average particle diameter and a number-average particle diameter of the carrier is about 1 to about 1.3, and wherein an electric resistance is from about 1.0×109 to about 1.Type: GrantFiled: September 28, 2006Date of Patent: September 18, 2007Assignee: Ricoh Company, Ltd.Inventors: Masahide Yamashita, Satoshi Mochizuki, Tomio Kondou, Kohsuke Suzuki
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Patent number: 7244539Abstract: A magnetic carrier includes a magnetic material-dispersed resin core containing at least a magnetic material and a binder resin. The surface of the magnetic material-dispersed resin core is coated with a coating material containing at least a fluorine resin and 1 to 40 parts by weight of fine particles based on 100 parts by weight of the fluorine resin. The coating material is in an amount of 0.3 to 4.0 parts by weight based on 100 parts by weight of the magnetic material-dispersed resin core. The magnetic carrier has a contact angle of 95 to 125°. A two-component developer is also provided which makes use of the magnetic carrier.Type: GrantFiled: April 29, 2004Date of Patent: July 17, 2007Assignee: Canon Kabushiki KaishaInventors: Yoshinobu Baba, Ryoichi Fujita, Takaaki Kaya, Kazuo Terauchi
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Patent number: 7223475Abstract: Carrier comprised of a core, a polymer coating, and wherein said coating contains a conductive polypyrrole contained in a carbon black matrix; or a polyaniline contained in a carbon black matrix.Type: GrantFiled: September 10, 2003Date of Patent: May 29, 2007Assignee: Xerox CorporationInventors: Samir Kumar, Thomas J. Budny, Brian S. Giannetto, Brian E. Moore, Scott M. Silence, Michael J. Duggan, Bernard A. Kelly