Patents by Inventor Kei Yasutomi

Kei Yasutomi 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: 6654579
    Abstract: An image forming apparatus including an image carrier including a conductive support, at least a photoconductive layer formed on the conductive support, and a surface protection layer formed on the photoconductive layer and including a charge injection layer. Also included is a charge member for charging the image carrier in contact with the surface protection layer when applied with a voltage. Further, the surface protection layer has a diamond-like structure or an amorphous structure containing hydrogen with a volume resistance of 109 &OHgr;·cm to 1012 &OHgr;·cm and a Knoop hardness of 400 Kg/mm2 or greater, and the charging member includes magnetic particles for charging having a mean particle size ranging from 20 &mgr;m to 150 &mgr;m. Also, a light transmission of the surface protective layer is 50% or more of a wavelength of light used for exposing the image carrier.
    Type: Grant
    Filed: October 25, 2002
    Date of Patent: November 25, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiko Shakuto, Kei Yasutomi, Hirokatsu Suzuki, Nobutaka Takeuchi, Toshihiko Baba
  • Publication number: 20030215264
    Abstract: An image formation apparatus using an elecrophotographic process for obtaining a high quality image with tone value R2 of equal to or more than 0.98 is provided. The resolution for light-writing is equal to or more than 1200 dpi and/or light-writing is performed based on image data formed by applying halftone processing at a line frequency of equal to or more than 200 lpi. Light-writing means is accomplished with a laser light beam with a beam diameter equal to or more than 35 &mgr;m. The photoconductor includes a charge generating layer containing a charge generating material and a charge transfer layer containing a charge transfer material laminated on a conductive support. The ionization potential of the charge generating material Ip(CG) and ionization potential of the charge transfer material Ip(CT) satisfy the relationship of Ip(CG)≧Ip(CT).
    Type: Application
    Filed: January 24, 2003
    Publication date: November 20, 2003
    Inventors: Kei Yasutomi, Yasuo Suzuki
  • Publication number: 20030210938
    Abstract: An image forming apparatus of the present invention includes a lubricator for applying a lubricant to an image carrier or a process unit around the image carrier to thereby reduce friction. The apparatus of the present invention insures a uniform halftone image, prevents the trailing edge of an image from being lost, and faithfully reproduces even a horizontal line.
    Type: Application
    Filed: June 12, 2003
    Publication date: November 13, 2003
    Inventors: Tsukuru Kai, Nobutaka Takeuchi, Hisashi Shoji, Kei Yasutomi, Takeyoshi Sekine, Osamu Ariizumi
  • Patent number: 6625409
    Abstract: An image forming apparatus including an image carrier having a conductive support, at least a photoconductive layer formed on the conductive support, and a surface protection layer formed on the photoconductive layer and including a charge injection layer. Also included is a charging member for charging the image carrier in contact with the surface protection layer when applied with a voltage, and a developing unit for developing a latent image formed on the image carrier with toner to thereby produce a corresponding toner image. Further, the surface protection layer has a diamond-like carbon structure or an amorphous structure containing hydrogen, the developing unit develops the latent image with a magnet brush formed by magnetic particles for development, and the charging member includes magnetic particles for charging having a mean particle size smaller than a mean particle size of the magnetic particles for development.
    Type: Grant
    Filed: October 25, 2002
    Date of Patent: September 23, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiko Shakuto, Kei Yasutomi, Hirokatsu Suzuki, Nobutaka Takeuchi, Toshihiko Baba
  • Patent number: 6597885
    Abstract: An image forming apparatus including a developing device and an image carrier facing the developing device. The developing device includes a main magnetic pole for causing a developer to magnetically deposit on an outer periphery of a developer carrier in a form of a magnet brush. The image carrier has a coefficient of friction of 0.5 or below, and a flux density in a normal direction has an attenuation ratio of 40% or above.
    Type: Grant
    Filed: June 5, 2001
    Date of Patent: July 22, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsukuru Kai, Nobutaka Takeuchi, Hisashi Shoji, Kei Yasutomi, Takeyoshi Sekine, Osamu Ariizumi
  • Publication number: 20030063923
    Abstract: An image forming apparatus includes a photoconductive element including a conductive support rotatably supported and a charge injection layer and a surface protection layer sequentially laminated on the conductive support. A charger includes a conductive body for injecting, when a preselected voltage is applied thereto, a charge in the charge injection layer in contact with the surface protection layer. A writing unit exposes the charged surface of the photoconductive element imagewise to thereby locally vary the potential deposited on the photoconductive element and electrostatically form a latent image. A developing unit develops the latent image to thereby produce a corresponding toner image. The toner image is transferred from the photoconductive element to a recording medium.
    Type: Application
    Filed: October 25, 2002
    Publication date: April 3, 2003
    Inventors: Kei Yasutomi, Hirokatsu Suzuki, Masahiko Shakuto, Nobutaka Takeuchi, Toshihiko Baba
  • Publication number: 20030049050
    Abstract: An image forming apparatus includes a photoconductive element including a conductive support rotatably supported and a charge injection layer and a surface protection layer sequentially laminated on the conductive support. A charger includes a conductive body for injecting, when a preselected voltage is applied thereto, a charge in the charge injection layer in contact with the surface protection layer. A writing unit exposes the charged surface of the photoconductive element imagewise to thereby locally vary the potential deposited on the photoconductive element and electrostatically form a latent image. A developing unit develops the latent image to thereby produce a corresponding toner image. The toner image is transferred from the photoconductive element to a recording medium.
    Type: Application
    Filed: October 25, 2002
    Publication date: March 13, 2003
    Inventors: Masahiko Shakuto, Tsukuru Kai, Hidetoshi Yano, Takahiko Tokumasu, Toshihiko Baba, Hiroshi Ikuno, Kei Yasutomi, Hirokatsu Suzuki, Nobutaka Takeuchi, Toshihiko Baba
  • Publication number: 20020122675
    Abstract: An electrophotographic image forming apparatus of the present invention frees images from various defects including the thinning of horizontal lines, the omission of the trailing edge an image, background contamination, granularity particular to a halftone image, carrier scattering, and image noise. Further, the apparatus of the present invention solves problems ascribable to patches used to sense image density. Moreover, the apparatus of the present invention faithfully reproduces tonality and has a high developing ability.
    Type: Application
    Filed: May 2, 2001
    Publication date: September 5, 2002
    Applicant: Ricoh Company, Ltd.
    Inventors: Hisashi Shoji, Tsukuru Kai, Kei Yasutomi, Nekka Matsuura, Nobutaka Takeuchi, Hirokatsu Suzuki
  • Patent number: 6366751
    Abstract: An image forming apparatus includes a photoconductive element including a conductive support rotatably supported and a charge injection layer and a surface protection layer sequentially laminated on the conductive support. A charger includes a conductive body for injecting, when a preselected voltage is applied thereto, a charge in the charge injection layer in contact with the surface protection layer. A writing unit exposes the charged surface of the photoconductive element imagewise to thereby locally vary the potential deposited on the photoconductive element and electrostatically form a latent image. A developing unit develops the latent image to thereby produce a corresponding toner image. The toner image is transferred from the photoconductive element to a recording medium.
    Type: Grant
    Filed: September 15, 2000
    Date of Patent: April 2, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiko Shakuto, Tsukuru Kai, Hidetoshi Yano, Takahiko Tokumasu, Hiroshi Ikuno, Kei Yasutomi, Hirokatsu Suzuki, Nobutaka Takeuchi, Toshihiko Baba
  • Publication number: 20020037187
    Abstract: An image forming apparatus of the present invention includes a lubricator for applying a lubricant to an image carrier or a process unit around the image carrier to thereby reduce friction. The apparatus of the present invention insures a uniform halftone image, prevents the trailing edge of an image from being lost, and faithfully reproduces even a horizontal line.
    Type: Application
    Filed: June 5, 2001
    Publication date: March 28, 2002
    Applicant: Ricoh Company, Ltd.
    Inventors: Tsukuru Kai, Nobutaka Takeuchi, Hisashi Shoji, Kei Yasutomi, Takeyoshi Sekine, Osamu Ariizumi
  • Patent number: 5999773
    Abstract: An image forming apparatus includes a rotatable image bearing member and a contact-charging member which contacts a surface of the image bearing member. The contact-charging member can charge the image bearing member by applying a predetermined voltage to the contact-charging member so that a potential of the contact-charging member is changed to a required potential for transferring a residual toner that is stuck on a surface of the contact-charging member facing the image bearing member onto the image bearing member while the image bearing member stops rotating. A method for removing residual toner sticking onto a contact-charging member that contacts a surface of the image bearing member changes a potential of the contact charging member to a required cleaning potential for transferring the residual toner sticking to a surface of the contact-charging member facing the image bearing member onto the contact-charging member while the image bearing member stops rotating.
    Type: Grant
    Filed: June 12, 1998
    Date of Patent: December 7, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Kei Yasutomi, Hidetoshi Yano, Masako Yoshii, Nobuto Yokokawa
  • Patent number: 5740494
    Abstract: An image forming apparatus includes a cleaning member for collecting toner left on an image carrier after image transfer, and then redepositing it on the carrier, so that a developing unit can collect the redeposited toner to reuse it. Even when the frictional charging ability of the cleaning member falls due to aging or varying environment, the charge of the toner left on the image carrier is regulated to preselected polarity before the toner reaches the cleaning member, thereby enhancing a toner collecting efficiency and a toner redepositing efficiency. The charge of the toner redeposited on the image carrier and moved away from the cleaning member is regulated to preselected polarity while being increased, thereby reducing a load to act on the developing unit. The toner is redeposited on the image carrier efficiently without regard to the polarity of the toner collected by the cleaning member.
    Type: Grant
    Filed: August 20, 1996
    Date of Patent: April 14, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Hisashi Shoji, Osamu Endo, Kei Yasutomi, Masako Yoshii, Hidetoshi Yano, Yasushi Nakazato, Takayuki Kimura