Patents by Inventor Hisao Murayama

Hisao Murayama 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: 7548712
    Abstract: A latent image carrier includes a thin-walled cylinder with a chargeable photosensitive layer. The latent image carrier is configured to form an electrostatic latent image corresponding to an optically written image. A cylindrical damper including an elastic body disposed inside the latent image carrier. A first end of the cylindrical damper includes a wall extending inward toward an axis of the damper. A second end of the damper, opposite the first end along the axis of the damper, includes an opening, which is open in an axial direction. The wall includes a through-hole connecting an internal cavity and an outside of the damper. An outer diameter of an outermost part of the first end of the damper along the axis of the damper is smaller than an outer diameter of an outermost part of the second end of the damper along the axis of the damper.
    Type: Grant
    Filed: August 17, 2007
    Date of Patent: June 16, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Takatsugu Fujishiro, Takeo Suda, Hideki Zemba, Hisao Murayama
  • Patent number: 7321742
    Abstract: An image forming apparatus includes a photoreceptor belt formed by either a belt or a thin-walled cylinder. A charging unit that sets bias characteristics of the photoreceptor belt has an arrangement to approach towards the photoreceptor belt. A damper is provided on a side of the photoreceptor belt opposite to the side facing the charging unit. The damper absorbs vibrations in the photoreceptor belt through a supporting plate.
    Type: Grant
    Filed: January 10, 2006
    Date of Patent: January 22, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Takatsugu Fujishiro, Takeo Suda, Hideki Zemba, Hisao Murayama
  • Publication number: 20080003017
    Abstract: A latent image carrier includes a thin-walled cylinder with a chargeable photosensitive layer. The latent image carrier is configured to form an electrostatic latent image corresponding to an optically written image. A cylindrical damper including an elastic body disposed inside the latent image carrier. A first end of the cylindrical damper includes a wall extending inward toward an axis of the damper. A second end of the damper, opposite the first end along the axis of the damper, includes an opening, which is open in an axial direction. The wall includes a through-hole connecting an internal cavity and an outside of the damper. An outer diameter of an outermost part of the first end of the damper along the axis of the damper is smaller than an outer diameter of an outermost part of the second end of the damper along the axis of the damper.
    Type: Application
    Filed: August 17, 2007
    Publication date: January 3, 2008
    Inventors: Takatsugu FUJISHIRO, Takeo SUDA, Hideki ZEMBA, Hisao MURAYAMA
  • Patent number: 7295795
    Abstract: An image forming method begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step. An impurity collecting device is associated with a pair of registration rollers which stop the recording medium for a moment to thereby synchronize the recording medium to the toner image.
    Type: Grant
    Filed: September 29, 2005
    Date of Patent: November 13, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Koji Suzuki, Hideaki Mochimaru, Naoki Iwata, Kunihiko Tomita, Hiroshi Yokoyama, Norimasa Sohmiya, Shigeru Watanabe, Chiemi Kaneko, Yasukuni Omata, Hisao Murayama
  • Patent number: 7197269
    Abstract: An image transferring device of the present invention includes a first and a second intermediate image transfer body whose surfaces endlessly move while forming a nip in contact with each other. When a sheet nipped by the nip is being conveyed toward a side downstream of the nip in the direction in which the above surfaces move, a first toner image transferred from an image carrier to the second intermediate image transfer body via the first intermediate image transfer body beforehand is transferred to one side of the sheet. At the same time, a second toner image transferred from the image carrier to the first image transfer body beforehand is transferred to the other side of the sheet. One of the two intermediate image transfer bodies is less deformable than the other intermediate image transfer body in the direction of thickness.
    Type: Grant
    Filed: October 8, 2003
    Date of Patent: March 27, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasukuni Omata, Hideaki Mochimaru, Chiemi Kaneko, Koji Suzuki, Naoki Iwata, Kunihiko Tomita, Hiroshi Yokoyama, Norimasa Sohmiya, Shigeru Watanabe, Hisao Murayama
  • Publication number: 20060127131
    Abstract: An image forming apparatus includes a photoreceptor belt formed by either a belt or a thin-walled cylinder. A charging unit that sets bias characteristics of the photoreceptor belt has an arrangement to approach towards the photoreceptor belt. A damper is provided on a side of the photoreceptor belt opposite to the side facing the charging unit. The damper absorbs vibrations in the photoreceptor belt through a supporting plate.
    Type: Application
    Filed: January 10, 2006
    Publication date: June 15, 2006
    Inventors: Takatsugu Fujishiro, Takeo Suda, Hideki Zemba, Hisao Murayama
  • Patent number: 7010246
    Abstract: An image forming apparatus includes a photoreceptor belt formed by either a belt or a thin-walled cylinder. A charging unit that sets bias characteristics of the photoreceptor belt has an arrangement to approach towards the photoreceptor belt. A damper is provided on a side of the photoreceptor belt opposite to the side facing the charging unit. The damper absorbs vibrations in the photoreceptor belt through a supporting plate.
    Type: Grant
    Filed: June 9, 2003
    Date of Patent: March 7, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Takatsugu Fujishiro, Takeo Suda, Hideki Zemba, Hisao Murayama
  • Patent number: 7003251
    Abstract: An image forming method of the present invention begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step. Additionally, the second image carrier has a greater roughness than the first image carrier.
    Type: Grant
    Filed: April 28, 2003
    Date of Patent: February 21, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Koji Suzuki, Hideaki Mochimaru, Naoki Iwata, Kunihiko Tomita, Hiroshi Yokoyama, Norimasa Sohmiya, Shigeru Watanabe, Chiemi Kaneko, Yasukuni Omata, Hisao Murayama
  • Publication number: 20060024095
    Abstract: An image forming method of the present invention begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step.
    Type: Application
    Filed: September 29, 2005
    Publication date: February 2, 2006
    Inventors: Koji Suzuki, Hideaki Mochimaru, Naoki Iwata, Kunihiko Tomita, Hiroshi Yokoyama, Norimasa Sohmiya, Shigeru Watanabe, Chiemi Kaneko, Yasukuni Omata, Hisao Murayama
  • Patent number: 6983117
    Abstract: An image forming apparatus of the present invention includes a first and a second intermediate image transfer belt contacting each other to form a nip for secondary image transfer. While the nip is heated, a sheet is passed through the nip to thereby transfer toner images respectively formed on the first and second belts to opposite surfaces of the sheet at the same time. The nip is sized such that image transfer and fixation can be effected at temperature higher than the melting point or the softening point of toner by 5° C. to 50° C.
    Type: Grant
    Filed: August 22, 2003
    Date of Patent: January 3, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Norimasa Sohmiya, Koji Suzuki, Hideaki Mochimaru, Naoki Iwata, Kunihiko Tomita, Hiroshi Yokoyama, Shigeru Watanabe, Chiemi Kaneko, Yasukuni Omata, Hisao Murayama
  • Patent number: 6898398
    Abstract: A printer includes a transfer belt unit and an intermediate transfer belt. Two papers are fed into the printer one after another at a desired interval. 2nd and 4th images are transferred first onto the transfer belt unit and then onto back surfaces of respective papers. 1st and 3rd images are transferred by the intermediate transfer belt directly onto front surfaces of the respective papers. The 2nd and 4th images are formed on the transfer belt unit in such a manner that a distance between the two images on the transfer belt unit is set longer than the interval between the two papers.
    Type: Grant
    Filed: May 9, 2003
    Date of Patent: May 24, 2005
    Assignee: Ricoh Company, Limited
    Inventors: Yasukuni Omata, Hideaki Mochimaru, Hisao Murayama
  • Publication number: 20040131398
    Abstract: An image transferring device of the present invention includes a first and a second intermediate image transfer body whose surfaces endlessly move while forming a nip in contact with each other. When a sheet nipped by the nip is being conveyed toward a side downstream of the nip in the direction in which the above surfaces move, a first toner image transferred from an image carrier to the second intermediate image transfer body via the first intermediate image transfer body beforehand is transferred to one side of the sheet. At the same time, a second toner image transferred from the image carrier to the first image transfer body beforehand is transferred to the other side of the sheet. One of the two intermediate image transfer bodies is less deformable than the other intermediate image transfer body in the direction of thickness.
    Type: Application
    Filed: October 8, 2003
    Publication date: July 8, 2004
    Inventors: Yasukuni Omata, Hideaki Mochimaru, Chiemi Kaneko, Koji Suzuki, Naoki Iwata, Kunihiko Tomita, Hiroshi Yokoyama, Norimasa Sohmiya, Shigeru Watanabe, Hisao Murayama
  • Publication number: 20040101332
    Abstract: An image forming apparatus of the present invention includes a first and a second intermediate image transfer belt contacting each other to form a nip for secondary image transfer. While the nip is heated, a sheet is passed through the nip to thereby transfer toner images respectively formed on the first and second belts to opposite surfaces of the sheet at the same time. The nip is sized such that image transfer and fixation can be effected at temperature higher than the melting point or the softening point of toner by 5° C. to 50° C.
    Type: Application
    Filed: August 22, 2003
    Publication date: May 27, 2004
    Inventors: Norimasa Sohmiya, Koji Suzuki, Hideaki Mochimaru, Naoki Iwata, Kunihiko Tomita, Hiroshi Yokoyama, Shigeru Watanabe, Chiemi Kaneko, Yasukuni Omata, Hisao Murayama
  • Publication number: 20040042822
    Abstract: An image forming apparatus includes a photoreceptor belt formed by either a belt or a thin-walled cylinder. A charging unit that sets bias characteristics of the photoreceptor belt has an arrangement to approach towards the photoreceptor belt. A damper is provided on a side of the photoreceptor belt opposite to the side facing the charging unit. The damper absorbs vibrations in the photoreceptor belt through a supporting plate.
    Type: Application
    Filed: June 9, 2003
    Publication date: March 4, 2004
    Inventors: Takatsugu Fujishiro, Takeo Suda, Hideki Zemba, Hisao Murayama
  • Publication number: 20030235443
    Abstract: A printer includes a transfer belt unit and an intermediate transfer. Two papers are fed into the printer one after another at a desired interval. 2nd and 4th images are transferred first onto the transfer belt unit and then onto back surfaces of respective papers. 1st and 3rd images are transferred by the intermediate transfer belt directly onto front surfaces of the respective papers. The 2nd and 4th images are formed on the transfer belt unit in such a manner that a distance between the two images on the transfer belt unit is set longer than the interval between the two papers.
    Type: Application
    Filed: May 9, 2003
    Publication date: December 25, 2003
    Inventors: Yasukuni Omata, Hideaki Mochimaru, Hisao Murayama
  • Publication number: 20030235442
    Abstract: An image forming method of the present invention begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step.
    Type: Application
    Filed: April 28, 2003
    Publication date: December 25, 2003
    Inventors: Koji Suzuki, Hideaki Mochimaru, Naoki Iwata, Kunihiko Tomita, Hiroshi Yokoyama, Norimasa Sohmiya, Shigeru Watanabe, Chiemi Kaneko, Yasukuni Omata, Hisao Murayama
  • Patent number: 5869213
    Abstract: A multicolor image forming method in which a plurality of latent images are sequentially formed and developed on an image carrier on top of each other on the image carrier. The second and any successive color toners are developed in a non-contact manner. A developed image on a photoconductive element is prevented from being contaminated by subsequent developing stages and toner on the photoconductive element is prevented from contaminating the developer in the subsequent developing stages by reducing the amount of toner which improperly flies between the photoconductive element and the developing stages. Such a prevention of the flight of toner can be accomplished by keeping the potential of the toner on the photoconductive element within a predetermined threshold of the voltage of the toner in the subsequent developing stages. Also, properties of the various toners can reduce the improper flight of the toner such as by controlling the relative amounts of hydrophobic SiO.sub.
    Type: Grant
    Filed: March 21, 1994
    Date of Patent: February 9, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoki Iwata, Tomotoshi Nakahara, Hisao Murayama, Ichiro Komuro
  • Patent number: 5737680
    Abstract: An image forming apparatus capable of collecting a toner remaining on an image carrier after image transfer and conveying the collected toner to a developing unit to reuse it. A toner supplement roller and a toner conveyor are so controlled as to maintain the supplement of a fresh toner from a hopper to the developing unit and the supplement of the collected toner from the toner conveyor to the developing unit in a ratio lying in a predetermined range.
    Type: Grant
    Filed: November 19, 1996
    Date of Patent: April 7, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiromitsu Takagaki, Shinji Kato, Hisao Murayama, Shigeru Watanabe, Mayumi Yoshida, Shunji Kato
  • Patent number: 5682572
    Abstract: An image density control method applicable to an electrophotographic copier or similar image recorder for controlling the toner concentration of a two-component developer, i.e., a mixture of toner and carrier to maintain the density of a toner image produced by the developer constant. Predetermined calculations are performed on the basis of the output of a photosensor which is responsive to the toner images representative of reference patterns formed on a photoconductive element.
    Type: Grant
    Filed: May 2, 1995
    Date of Patent: October 28, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuo Murai, Shinji Kato, Hisao Murayama
  • Patent number: 5604575
    Abstract: An image forming apparatus capable of collecting a toner remaining on an image carrier after image transfer and conveying the collected toner to a developing unit to reuse it. A toner supplement roller and a toner conveyor are so controlled as to maintain the supplement of a fresh toner from a hopper to the developing unit and the supplement of the collected toner from the toner conveyor to the developing unit in a ratio lying in a predetermined range.
    Type: Grant
    Filed: May 15, 1995
    Date of Patent: February 18, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiromitsu Takagaki, Shinji Kato, Hisao Murayama, Shigeru Watanabe, Mayumi Yoshida, Shunji Kato