Patents by Inventor Shuuichi Nakagawa
Shuuichi Nakagawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8526864Abstract: An image developer, including a developer container containing a developer developing a latent image on a latent image bearer; a developer bearer bearing the developer, located close to or contacting the latent image bearer; and a developer feeding and collection roller feeding the developer onto the developer bearer and scraping the developer therefrom, rotating while contacting thereto with pressure, wherein the developer feeding and collection roller includes an inner layer formed of an electroconductive foamed rubber; and an outer layer formed of an insulative foamed rubber, and wherein the following relationship is satisfied: ??T wherein ? represents a compression amount of the pressure of the developer feeding and collection roller to the developer bearer; and T represents a thickness of the outer layer, and wherein an offset voltage having a polarity opposite to that of the charged developer is applied to the developer feeding and collection roller.Type: GrantFiled: March 25, 2011Date of Patent: September 3, 2013Assignee: Ricoh Company, Ltd.Inventors: Shuuichi Nakagawa, Chiyoshi Nozaki, Hideaki Yasunaga, Keiichiro Juri
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Publication number: 20130136508Abstract: To provide a developing apparatus, including: a developer bearing member which carries a one-component developer; a charge imparting member disposed in contact with the developer bearing member and charges the one-component developer on the developer bearing member; and a bias supplying member which supplies a bias voltage to the charge imparting member, wherein the one-component developer has a volume resistivity of 8.0 log?·cm to 10.9 log?·cm, and the developing apparatus satisfies: (K?1)0.75/v0.25<0.7×RT?6.6 where: v [m/sec] is a surface moving speed of a latent image bearing member contacting the developer bearing member at a surface moving in an identical direction as the developer bearing member; v? [m/sec] is a surface moving speed of the developer bearing member; K is a ratio v?/v; and RT [log?·cm] is a volume resistivity of the one-component developer.Type: ApplicationFiled: November 21, 2012Publication date: May 30, 2013Inventor: Shuuichi NAKAGAWA
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Patent number: 8346150Abstract: In a fixing device, an opposing member contacts a heating member to form a fixing nip between the heating member and the opposing member. A driver rotatively drives at least one of the heating member and the opposing member. A sheet supplier supplies and conveys a sheet to the fixing nip. A recording medium bearing an unfixed toner image is conveyed through a gap between the sheet and the opposing member at the fixing nip with a side of the recording medium bearing the unfixed toner image facing the sheet. At least one of the rotating heating member and the rotating opposing member applies a driving force to the sheet supplied to the fixing nip while the sheet contacts the sheet supplier to apply tension to the sheet at a position upstream from the fixing nip in a sheet conveyance direction.Type: GrantFiled: March 31, 2010Date of Patent: January 1, 2013Assignee: Ricoh Company, Ltd.Inventors: Tomofumi Inoue, Shuuichi Nakagawa, Hidekazu Shono
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Patent number: 8329080Abstract: A conductive composition including a matrix resin comprising a thermoplastic resin, a conductive agent comprising a carbon black having an amine value of 1 to 100 mgKOH/g, and a stiffening agent comprising an acid anhydride, a carboxylic acid, or a compound having an epoxy group.Type: GrantFiled: April 1, 2011Date of Patent: December 11, 2012Assignee: Ricoh Company, Ltd.Inventors: Makoto Matsushita, Chiyoshi Nozaki, Shuuichi Nakagawa, Akira Izutani
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Patent number: 8295755Abstract: When a gloss application sheet is conveyed through a nip formed between a first nip formation member and a second nip formation member pressing against each other, the gloss application sheet is sandwiched between the first nip formation member and a recording medium simultaneously conveyed through the nip. The gloss application sheet includes a first contact surface contacting the first nip formation member and a second contact surface disposed opposite the first contact surface for contacting the recording medium. The first contact surface has a reduced adhesive force compared to the second contact surface.Type: GrantFiled: June 25, 2010Date of Patent: October 23, 2012Assignee: Ricoh Company, Ltd.Inventors: Hidekazu Shono, Shuuichi Nakagawa, Tomofumi Inoue
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Publication number: 20120237270Abstract: A developing roller including: an electrically-conductive base; an elastic layer formed on an outer circumference of the electrically-conductive base; and a toner bearing layer formed on the elastic layer, wherein the toner bearing layer contains a polyurethane resin having an isocyanurate structure, and wherein the polyurethane resin has a ratio A/B of 1.0 to 10.0 where A denotes absorbance attributed to C?O of cyanurate and B denotes absorbance attributed to C?O of urethane in an infrared absorption spectrum of the polyurethane resin obtained by an ATR method.Type: ApplicationFiled: March 16, 2012Publication date: September 20, 2012Inventors: Keiichiro JURI, Chiyoshi Nozaki, Hideaki Yasunaga, Shuuichi Nakagawa
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Patent number: 8185025Abstract: A developing device develops an electrostatic latent image formed on an image carrier with toner. The developing device includes a developer carrier, a developer supplying unit that supplies a developer on the developer carrier, a layer shaping member that shapes the developer supplied on the developer carrier into a thin layer, and an electric-field control member that is arranged downstream of a shaping nip formed between the developer carrier and the layer shaping member and that controls an intensity of an electric field generated between the developer carrier and the layer shaping member.Type: GrantFiled: July 21, 2009Date of Patent: May 22, 2012Assignee: Ricoh Company, LimitedInventors: Shintaro Yamada, Shin Murayama, Ryuji Inoue, Shuuichi Nakagawa, Kazushige Ohnishi
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Publication number: 20110249994Abstract: A conductive composition including a matrix resin comprising a thermoplastic resin, a conductive agent comprising a carbon black having an amine value of 1 to 100 mgKOH/g, and a stiffening agent comprising an acid anhydride, a carboxylic acid, or a compound having an epoxy group.Type: ApplicationFiled: April 1, 2011Publication date: October 13, 2011Inventors: Makoto Matsushita, Chiyoshi Nozaki, Shuuichi Nakagawa, Akira Izutani
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Publication number: 20110243616Abstract: An image developer, including a developer container containing a developer developing a latent image on a latent image bearer; a developer bearer bearing the developer, located close to or contacting the latent image bearer; and a developer feeding and collection roller feeding the developer onto the developer bearer and scraping the developer therefrom, rotating while contacting thereto with pressure, wherein the developer feeding and collection roller includes an inner layer formed of an electroconductive foamed rubber; and an outer layer formed of an insulative foamed rubber, and wherein the following relationship is satisfied: ??T wherein ? represents a compression amount of the pressure of the developer feeding and collection roller to the developer bearer; and T represents a thickness of the outer layer, and wherein an offset voltage having a polarity opposite to that of the charged developer is applied to the developer feeding and collection roller.Type: ApplicationFiled: March 25, 2011Publication date: October 6, 2011Applicant: RICOH COMPANY, LTD.Inventors: Shuuichi NAKAGAWA, Chiyoshi Nozaki, Hideaki Yasunaga, Keiichiro Juri
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Patent number: 7945195Abstract: A developer regulating member capable of stably regulating the thickness of a developer even when used for a long time, while preventing the increase in the production cost, a developing device having the developer regulating member, an image forming apparatus having the developing device, a process cartridge, and a method of producing the developer regulating member. The average crystal particle diameter D [?m] of a plate-like member provided in a layer-thinning blade which functions as the developer regulating member and which abuts against a developing roller functioning as a developer carrier, and the curvature radius R [?m] of a bent portion satisfy the relationship of D?60.53×R×10?3?12.61.Type: GrantFiled: November 29, 2007Date of Patent: May 17, 2011Assignee: Ricoh Company, Ltd.Inventors: Ryuji Inoue, Shuuichi Nakagawa, Shin Murayama, Rumi Konishi, Shintaro Yamada, Kazushige Oonishi
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Patent number: 7890033Abstract: A developing device that prevents the formation of agglomerated masses of developing agent in the bottom of the developing agent housing chamber near the developing roller and the supply roller, and that maintains the fluidity of the developing agent in the bottom of the developing agent housing chamber, while minimizing any increase in size of the developing device.Type: GrantFiled: December 27, 2007Date of Patent: February 15, 2011Assignee: Ricoh Company, Ltd.Inventors: Shin Murayama, Shuuichi Nakagawa, Ryuji Inoue, Shintaro Yamada
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Publication number: 20110013958Abstract: When a gloss application sheet is conveyed through a nip formed between a first nip formation member and a second nip formation member pressing against each other, the gloss application sheet is sandwiched between the first nip formation member and a recording medium simultaneously conveyed through the nip. The gloss application sheet includes a first contact surface contacting the first nip formation member and a second contact surface disposed opposite the first contact surface for contacting the recording medium. The first contact surface has a reduced adhesive force compared to the second contact surface.Type: ApplicationFiled: June 25, 2010Publication date: January 20, 2011Inventors: Hidekazu SHONO, Shuuichi NAKAGAWA, Tomofumi INOUE
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Patent number: 7865118Abstract: A developing device that can reliably supply toner from a toner supply roller to a developing roller and that does not generate scraping irregularities in the toner thin layer on the developing roller, and a process cartridge and an image forming apparatus having the same. The developing device has: a toner supply chamber; a developing roller provided in the toner supply chamber; a toner supply roller provided in the toner supply chamber for supplying toner to the developing roller; and a layer regulation member for forming the toner on the developing roller into a thin layer, and develops electrostatic latent images on an image carrier by applying bias voltage to the developing roller. An intermediate contact member is interposed between the developing roller and the toner supply roller.Type: GrantFiled: February 4, 2009Date of Patent: January 4, 2011Assignee: Ricoh Company, Ltd.Inventors: Shuuichi Nakagawa, Ryuji Inoue, Shin Murayama, Kazushige Ohnishi, Shintaro Yamada
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Patent number: 7835652Abstract: An image developing method is disclosed that is able to efficiently remove degraded toner on a developing agent carrier, prevent formation of abnormal images, ensure good image quality over time, and increase the service life of the device. The developing method includes a step of calculating an amount of consumption of the developing agent during image formation and an amount of consumption of the developing agent in a compulsory toner consumption mode under different calculation conditions between the image formation and the compulsory toner consumption mode. In the compulsory toner consumption mode, a developing bias different from a developing bias used during image formation is applied for a predetermined time period to discharge residual developing agent on a developing agent carrier to a latent image carrier.Type: GrantFiled: April 28, 2008Date of Patent: November 16, 2010Assignee: Ricoh Company, Ltd.Inventors: Rumi Konishi, Shuuichi Nakagawa, Ryuji Inoue, Shin Murayama, Kazushige Oonishi, Shintaro Yamada
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Patent number: 7831182Abstract: A disclosed developing device includes a developing roller; a supply roller that is in contact with the developing roller and configured to supply toner to the developing roller; a current measuring unit configured to measure an electric current that flows from the developing roller to the supply roller when the toner is supplied from the supply roller to the developing roller; and an error determining unit configured to detect a development error of the developing roller based on the electric current measured by the current measuring unit.Type: GrantFiled: April 8, 2008Date of Patent: November 9, 2010Assignee: Ricoh Company, Ltd.Inventors: Rumi Konishi, Kenji Asuwa, Yoshiko Ogawa, Shuuichi Nakagawa, Ryuji Inoue, Shin Murayama, Kazushige Oonishi, Shintaro Yamada
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Publication number: 20100266304Abstract: In a fixing device, an opposing member contacts a heating member to form a fixing nip between the heating member and the opposing member. A driver rotatively drives at least one of the heating member and the opposing member. A sheet supplier supplies and conveys a sheet to the fixing nip. A recording medium bearing an unfixed toner image is conveyed through a gap between the sheet and the opposing member at the fixing nip with a side of the recording medium bearing the unfixed toner image facing the sheet. At least one of the rotating heating member and the rotating opposing member applies a driving force to the sheet supplied to the fixing nip while the sheet contacts the sheet supplier to apply tension to the sheet at a position upstream from the fixing nip in a sheet conveyance direction.Type: ApplicationFiled: March 31, 2010Publication date: October 21, 2010Inventors: Tomofumi INOUE, Shuuichi Nakagawa, Hidekazu Shono
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Developing device including an advance impeding member and an image forming apparatus using the same
Patent number: 7680443Abstract: A developing device is provided with which the increase in torque of a supply roller, unevenness of image density, and wear to the supply roller caused by the formation of an aggregated block of toner in the gap between the supply roller and the opposing side wall of a supply developer holding chamber can be suppressed.Type: GrantFiled: February 9, 2007Date of Patent: March 16, 2010Assignee: Ricoh Company, Ltd.Inventors: Shin Murayama, Shuuichi Nakagawa, Ryuji Inoue, Shintaro Yamada -
Patent number: 7676184Abstract: A developing apparatus is disclosed that includes a developer carrier for carrying a developer used for developing a latent image, a developer supplying chamber having a developer supplying member for supplying the developer to the developer carrier by rotation, a developer storing chamber positioned above the developer supplying chamber for storing the developer and supplying the developer to the developer supplying chamber, and a partitioning member positioned between the developer supplying chamber and the developer storing chamber. The partitioning member has an opening through which the developer is supplied from the developer storing chamber to the developer supplying chamber. The developing apparatus includes a conveying member positioned above the partitioning member for conveying the developer in a substantially horizontal direction.Type: GrantFiled: November 30, 2007Date of Patent: March 9, 2010Assignee: Ricoh Company, Ltd.Inventors: Shin Murayama, Shuuichi Nakagawa, Ryuji Inoue, Yuji Nagatomo, Shintaro Yamada, Kazushige Oonishi, Hirobumi Ooyoshi, Tomofumi Yoshida
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Publication number: 20100028057Abstract: A developing device develops an electrostatic latent image formed on an image carrier with toner. The developing device includes a developer carrier, a developer supplying unit that supplies a developer on the developer carrier, a layer shaping member that shapes the developer supplied on the developer carrier into a thin layer, and an electric-field control member that is arranged downstream of a shaping nip formed between the developer carrier and the layer shaping member and that controls an intensity of an electric field generated between the developer carrier and the layer shaping member.Type: ApplicationFiled: July 21, 2009Publication date: February 4, 2010Inventors: Shintaro YAMADA, Shin MURAYAMA, Ryuji INOUE, Shuuichi NAKAGAWA, Kazushige OHNISHI
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Publication number: 20090297976Abstract: A toner kit including a color toner containing a first binder resin and a coloring agent; transparent and colorless resin particulates comprising a second binder resin, wherein the half effusion temperature of the color toner and the half effusion temperature of the transparent and colorless resin particulates measured by a flow tester satisfy the following relationship: (the half effusion temperature of the color toner measured by the flow tester)?(the half effusion temperature of the transparent and colorless particulates measured by the flow tester)>30° C.Type: ApplicationFiled: June 2, 2009Publication date: December 3, 2009Inventors: Atsushi YAMAMOTO, Tsuyoshi Nozaki, Shuuichi Nakagawa