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).

  • Patent number: 8526864
    Abstract: 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: Grant
    Filed: March 25, 2011
    Date of Patent: September 3, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Shuuichi Nakagawa, Chiyoshi Nozaki, Hideaki Yasunaga, Keiichiro Juri
  • Publication number: 20130136508
    Abstract: 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: Application
    Filed: November 21, 2012
    Publication date: May 30, 2013
    Inventor: Shuuichi NAKAGAWA
  • Patent number: 8346150
    Abstract: 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: Grant
    Filed: March 31, 2010
    Date of Patent: January 1, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Tomofumi Inoue, Shuuichi Nakagawa, Hidekazu Shono
  • Patent number: 8329080
    Abstract: 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: Grant
    Filed: April 1, 2011
    Date of Patent: December 11, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Makoto Matsushita, Chiyoshi Nozaki, Shuuichi Nakagawa, Akira Izutani
  • Patent number: 8295755
    Abstract: 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: Grant
    Filed: June 25, 2010
    Date of Patent: October 23, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Hidekazu Shono, Shuuichi Nakagawa, Tomofumi Inoue
  • Publication number: 20120237270
    Abstract: 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: Application
    Filed: March 16, 2012
    Publication date: September 20, 2012
    Inventors: Keiichiro JURI, Chiyoshi Nozaki, Hideaki Yasunaga, Shuuichi Nakagawa
  • Patent number: 8185025
    Abstract: 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: Grant
    Filed: July 21, 2009
    Date of Patent: May 22, 2012
    Assignee: Ricoh Company, Limited
    Inventors: Shintaro Yamada, Shin Murayama, Ryuji Inoue, Shuuichi Nakagawa, Kazushige Ohnishi
  • Publication number: 20110249994
    Abstract: 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: Application
    Filed: April 1, 2011
    Publication date: October 13, 2011
    Inventors: Makoto Matsushita, Chiyoshi Nozaki, Shuuichi Nakagawa, Akira Izutani
  • Publication number: 20110243616
    Abstract: 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: Application
    Filed: March 25, 2011
    Publication date: October 6, 2011
    Applicant: RICOH COMPANY, LTD.
    Inventors: Shuuichi NAKAGAWA, Chiyoshi Nozaki, Hideaki Yasunaga, Keiichiro Juri
  • Patent number: 7945195
    Abstract: 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: Grant
    Filed: November 29, 2007
    Date of Patent: May 17, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryuji Inoue, Shuuichi Nakagawa, Shin Murayama, Rumi Konishi, Shintaro Yamada, Kazushige Oonishi
  • Patent number: 7890033
    Abstract: 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: Grant
    Filed: December 27, 2007
    Date of Patent: February 15, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Shin Murayama, Shuuichi Nakagawa, Ryuji Inoue, Shintaro Yamada
  • Publication number: 20110013958
    Abstract: 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: Application
    Filed: June 25, 2010
    Publication date: January 20, 2011
    Inventors: Hidekazu SHONO, Shuuichi NAKAGAWA, Tomofumi INOUE
  • Patent number: 7865118
    Abstract: 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: Grant
    Filed: February 4, 2009
    Date of Patent: January 4, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Shuuichi Nakagawa, Ryuji Inoue, Shin Murayama, Kazushige Ohnishi, Shintaro Yamada
  • Patent number: 7835652
    Abstract: 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: Grant
    Filed: April 28, 2008
    Date of Patent: November 16, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Rumi Konishi, Shuuichi Nakagawa, Ryuji Inoue, Shin Murayama, Kazushige Oonishi, Shintaro Yamada
  • Patent number: 7831182
    Abstract: 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: Grant
    Filed: April 8, 2008
    Date of Patent: November 9, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Rumi Konishi, Kenji Asuwa, Yoshiko Ogawa, Shuuichi Nakagawa, Ryuji Inoue, Shin Murayama, Kazushige Oonishi, Shintaro Yamada
  • Publication number: 20100266304
    Abstract: 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: Application
    Filed: March 31, 2010
    Publication date: October 21, 2010
    Inventors: Tomofumi INOUE, Shuuichi Nakagawa, Hidekazu Shono
  • Patent number: 7680443
    Abstract: 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: Grant
    Filed: February 9, 2007
    Date of Patent: March 16, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Shin Murayama, Shuuichi Nakagawa, Ryuji Inoue, Shintaro Yamada
  • Patent number: 7676184
    Abstract: 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: Grant
    Filed: November 30, 2007
    Date of Patent: March 9, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Shin Murayama, Shuuichi Nakagawa, Ryuji Inoue, Yuji Nagatomo, Shintaro Yamada, Kazushige Oonishi, Hirobumi Ooyoshi, Tomofumi Yoshida
  • Publication number: 20100028057
    Abstract: 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: Application
    Filed: July 21, 2009
    Publication date: February 4, 2010
    Inventors: Shintaro YAMADA, Shin MURAYAMA, Ryuji INOUE, Shuuichi NAKAGAWA, Kazushige OHNISHI
  • Publication number: 20090297976
    Abstract: 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: Application
    Filed: June 2, 2009
    Publication date: December 3, 2009
    Inventors: Atsushi YAMAMOTO, Tsuyoshi Nozaki, Shuuichi Nakagawa