Patents by Inventor Toshitaka Yamaguchi

Toshitaka Yamaguchi 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: 6144822
    Abstract: An image forming apparatus is provided, which includes an image bearing member, a transfer roller having a shaft for transferring an image on the image bearing member to a transfer sheet, a bearing mechanism for supporting the shaft, a discharging device for discharging the transfer, and a joint mechanism which mechanically connects the discharging device with the transfer roller at both ends of the shaft. Both of the transfer roller and the discharging device can be integrally detached from and attached to the image forming apparatus without detaching/attaching the bearing mechanism, by use of a handle. Therefore, an operation for replacing the transfer roller and the discharging device can be performed easily.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: November 7, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Toshitaka Yamaguchi, Masaru Tanaka, Hiroshi Mizusawa, Kenzo Tatsumi, Ken Amemiya, Haruji Mizuishi, Hideki Zemba, Noriyuki Usui, Mayumi Ohori
  • Patent number: 6055388
    Abstract: An image forming apparatus includes an image bearing member, a latent image forming device that forms a latent image on the image bearing member, a developing device that develops latent image on said image bearing member to a toner image with a two-component developer, and a toner density detecting device that detects toner density of the two-component developer in which the toner image is formed and outputted as a visible image onto a transfer member. A control device is provided for agitating the developer for a predetermined time period during an initial setting is performed for the developer, detecting a toner density of said developer after the predetermined agitation, and performing an abnormal process when a result of the detection is out of the predetermined range.
    Type: Grant
    Filed: April 3, 1998
    Date of Patent: April 25, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigeru Watanabe, Masaru Tanaka, Haruji Mizuishi, Kenzou Tatsumi, Toshitaka Yamaguchi, Takeo Suda, Hiroshi Yoshinaga, Ken Amemiya, Mayumi Oh-Hori
  • Patent number: 6006050
    Abstract: An image forming apparatus including an image bearing member, a latent image forming device which forms a latent image on the image bearing member, a developing device which develops the latent image using a two-component developer including a toner and a carrier and a toner supplying device which supplies toner into the developing device. A developer agitating device agitates developer in the developing device and a toner-density detecting device detects a toner density of developer in the developing device. A toner-density control device controls the toner density by operating the toner supplying device on the basis of a detected result according to the toner-density detecting device. A memory device stores resultant value of the toner density detected by the toner-density detecting device during image forming operations. The toner-density detecting device detects the toner density in a warm-up operation before starting the image forming operation by the image forming apparatus.
    Type: Grant
    Filed: October 30, 1997
    Date of Patent: December 21, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigeru Watanabe, Masaru Tanaka, Haruji Mizuishi, Toshitaka Yamaguchi, Kenzou Tatsumi, Hiroshi Yoshinaga, Takeo Suda, Ken Amemiya, Mayumi Oh-Hori
  • Patent number: 5923935
    Abstract: An image forming apparatus which transfers a toner image formed on an image carrier to a recording medium with a transfer device and separates the recording medium from the image carrier by discharging the recording medium with a discharging device. The image forming apparatus includes a support member which supports the transfer device and which includes a first support element pivotally mounted to a main body of the apparatus and a second support element. The second support element is pivotally mounted to the first support element at one end and unattached at the other end. The second support element may be solely supported by the first support element. The first support element is supported from below and by pivoting a support member out from under the first support element, the transfer device moves between a working position facing a surface of the image carrier and a recessed position separated from the image carrier by a larger distance than when the transfer device is in the working position.
    Type: Grant
    Filed: December 30, 1996
    Date of Patent: July 13, 1999
    Assignee: Ricoh Company, Ltd.
    Inventor: Toshitaka Yamaguchi
  • Patent number: 5915143
    Abstract: An image forming apparatus which is capable of adjusting toner density in response to variations of humidity. The image forming apparatus includes a toner density detector that detects the density of toner inside an image developer, a humidity detector that detects toner humidity inside the image forming apparatus, and a controller that controls a toner supplier on the basis of the toner density detected by the toner density detector and that adjusts the toner density in accordance with variations of humidity detected by the humidity detector. The humidity detector is located at a position where the humidity detector can detect humidity of air around the image developer and where the humidity detector is minimally affected by heated air.
    Type: Grant
    Filed: June 30, 1997
    Date of Patent: June 22, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigeru Watanabe, Masaru Tanaka, Haruji Mizuishi, Hiroshi Yoshinaga, Kenzo Tatsumi, Toshitaka Yamaguchi, Takeo Suda, Ken Amemiya, Mayumi Ohori
  • Patent number: 5887224
    Abstract: There is provided an image forming device capable of preventing smudges on the background of an image due to excess toner replenishment caused by a failure in stirring developer and toner enough to charge the toner or scattering of replenished toner without being charged. A toner conveying member for conveying replenished toner from a toner replenishing portion through a toner replenishing port to a developer stirring and conveying member is constructed by a screw member unitarily formed with the developer stirring and conveying member. The screw member has a spiral conveying fin capable of conveying the replenished toner at relatively high speed. The replenished toner is delivered to a toner replenishing portion provided in the upstream of a developer receiving portion of the screw member.
    Type: Grant
    Filed: May 23, 1997
    Date of Patent: March 23, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Haruji Mizuishi, Masaru Tanaka, Shigeru Watanabe, Kenzo Tatsumi, Toshitaka Yamaguchi, Takeo Suda, Hiroshi Yoshinaga, Ken Amemiya, Mayumi Yoshida
  • Patent number: 5815767
    Abstract: In an image forming apparatus, a latent image electrostatically formed on a photoconductive element is developed by a two-ingredient type developer consisting of toner and carrier. The photoconductive element has a life coincident with the life of the developer. When the photoconductive element and developer reach the end of their life, they are replaced at the same time.
    Type: Grant
    Filed: May 16, 1997
    Date of Patent: September 29, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Akio Kutsuwada, Masaru Tanaka, Takeo Suda, Mitsuru Sato, Toshitaka Yamaguchi, Kenzou Tatsumi
  • Patent number: 5697020
    Abstract: An image forming apparatus having a device for moving a charging roller towards and away from a photoreceptor and a cleaning member for the charging roller. The charging roller moving device moves the charging roller to positions including a first position where the charging roller is in contact with the photoreceptor and is separated from the cleaning member for a charging operation, a second position where the charging roller is in contact with the cleaning member for cleaning the surface of the charging roller and a third position where the charging roller is separated from the photoreceptor and the cleaning member. Even if the apparatus is left unoperated for a long time, the photoreceptor is prevented from being contaminated by the charging roller by placing the charging roller in the third position.
    Type: Grant
    Filed: January 18, 1996
    Date of Patent: December 9, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Mitsuru Sato, Akio Kutsuwada, Takeshi Saito, Toshitaka Yamaguchi
  • Patent number: 5678125
    Abstract: In an image forming apparatus, a latent image electrostatically formed on a photoconductive element is developed by a two-ingredient type developer consisting of toner and carrier. The photoconductive element has a life coincident with the life of the developer. When the photoconductive element and developer reach the end of their life, they are replaced at the same time.
    Type: Grant
    Filed: May 16, 1996
    Date of Patent: October 14, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Akio Kutsuwada, Masaru Tanaka, Takeo Suda, Mitsuru Sato, Toshitaka Yamaguchi, Kenzou Tatsumi
  • Patent number: 5400127
    Abstract: A toner recovery system is adapted to an image forming apparatus which carries out an image forming operation to form prints of a toner image on a photosensitive body using a toner.
    Type: Grant
    Filed: November 24, 1993
    Date of Patent: March 21, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Makoto Arai, Yasushi Koichi, Toshitaka Yamaguchi, Yoshiyuki Tanimoto
  • Patent number: 5396319
    Abstract: A cleaning device for an image forming apparatus in which a shock generation device is provided for imparting an impact force to a cleaning blade in an axial direction of a photoconductive member in order to prevent an edge portion of the cleaning blade from accumulating debris such as minute paper powder and toner, and thereby maintain a high quality image. The cleaning device can be controlled so that operation of the shock generation device for providing an impact force to the cleaning blade starts simultaneously as revolution of a photoconductive member starts, such that the foreign materials are effectively removed from a cleaning blade.
    Type: Grant
    Filed: September 22, 1993
    Date of Patent: March 7, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Masaki Tokuhashi, Makoto Arai, Masato Yanagida, Toshitaka Yamaguchi, Hiroshi Ono