Patents by Inventor Narihito Kojima

Narihito Kojima 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: 5390015
    Abstract: In an electrophotographic image formation method including the steps of uniformly charging a photoconductor, exposing the charged photoconductor to a digitally-processed light image to form a latent electrostatic image, and developing the latent electrostatic image by reverse development with a dry type two-component developer composed of a carrier and a toner to a toner image, transferring the toner image to a transfer sheet, and cleaning the photoconductor to remove the remaining developer from the surface of the photoconductor, a carrier removing device including a magnet with a magentic flux density of 400 to 2000 Gauss is provided between the development step and the cleaning step.
    Type: Grant
    Filed: August 3, 1993
    Date of Patent: February 14, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Nagame, Narihito Kojima
  • Patent number: 5264903
    Abstract: A cleaning unit for use in an image-formation apparatus including a photoconductor, provided with a cleaning member which can be brought into contact with the surface of the photoconductor and is made of an activated carbon fiber as the main component.
    Type: Grant
    Filed: May 20, 1991
    Date of Patent: November 23, 1993
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Nagame, Narihito Kojima
  • Patent number: 5147751
    Abstract: An electrophotographic photoconductor comprises (a) an electroconductive support, (b) a photoconductive layer formed thereon comprising a selenium alloy, and (c) a protective layer which is formed on the photoconductive layer, contains a binder resin component and an anti-oxidizing agent. In an electrophotographic copying process and an electrophographic copying apparatus using this photoconductor, the protective layer is abraded at a predetermined rate during the copying process in such a fashion that the anti-oxidizing agent contained in the protective layer is always present at the surface of the protective layer, thereby protecting the photoconductor from ozone and ions which are generated during corona charging of the photoconductor.
    Type: Grant
    Filed: October 22, 1991
    Date of Patent: September 15, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Narihito Kojima, Hiroshi Nagame, Mitsuru Seto, Takashi Rokutanzono, Shinji Nousho
  • Patent number: 5080947
    Abstract: An information recording medium comprises a substrate and a recording film layer thereon comprising a hydrocarbon polymer and finely-divided particles of a metallic component dispersed therein, which recording film layer is a plasma polymerized film prepared by subjecting an organic metallic complex containing a center metal to glow discharging decomposition. The metallic component in the recording film layer may be a metal, a metal oxide or a composition of a metal and a metallic oxide.
    Type: Grant
    Filed: February 9, 1990
    Date of Patent: January 14, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Katsuyuki Yamada, Narihito Kojima, Yukio Ide, Makoto Harigaya, Hiroko Iwasaki
  • Patent number: 5059502
    Abstract: An electrophotographic photoconductor comprises an electroconductive substrate, an organic photoconductive layer formed on the electroconductive substrate, and a protective layer formed on the organic photoconductive layer, comprising carbon or a carbon-based material as its main component, in which the difference in the Vickers hardness between the organic photoconductive layer and the protective layer is 2500 Kg/mm.sup.2 or less, and the oxygen concentration at the interface or in the vicinity of the interface between the organic photoconductive layer and the protective layer is 1 atom % or less.
    Type: Grant
    Filed: November 13, 1989
    Date of Patent: October 22, 1991
    Assignees: Ricoh Company, Ltd., Semiconductor Energy Laboratory Company Co., Ltd.
    Inventors: Narihito Kojima, Hiroshi Nagame, Mitsuru Seto, Shunpei Yamazaki, Shigenori Hayashi, Noriya Ishida, Naoki Hirose, Mari Sasaki, Junichi Takeyama
  • Patent number: 5008172
    Abstract: An electrophotographic photoconductor is disclosed, which comprises an electroconductive substrate, a photoconductive layer formed on the electroconductive substrate, and a protective layer formed on the photoconductive layer, the protective layer comprising a binder resin and finely-divided particles of at least one metal oxide with the surface thereof being coated with a coupling agent selected from the group consisting of a titanate-type coupling agent, a fluorine-containing silane coupling agent, and an acetoalkoxyaluminum diisopropylate, dispersed in the binder resin.
    Type: Grant
    Filed: May 24, 1989
    Date of Patent: April 16, 1991
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Rokutanzono, Yukio Ide, Hiroshi Nagame, Kohichi Ohshima, Narihito Kojima, Shinji Nousho
  • Patent number: 4957839
    Abstract: An electrophotographic photoconductor is disclosed, which comprises an electroconductive layer, on which are formed in order, a photoconductive layer, a charge retention layer and a protective layer, optionally an adhesive layer between the charge retention layer and the protective layer, the charge retention layer comprising a silicone resin which comprises: (a) 50 wt. % to 80 wt. % of silicone and oxygen, (b) 10 wt. % to 30 wt. % of carbon, (c) 1 wt. % to 10 wt. % of hydrogen, and (d) 1 wt. % to 10 wt. % of nitrogen. The photoconductive layer may comprise an As-Se alloy, in which case, it is preferable that the amount of As be in the range of 33 wt. % to 38 wt. % and the balance thereof be Se in the As-Se alloy. Preferably the adhesive layer comprises a hardened material containing a metal alkoxide.
    Type: Grant
    Filed: November 21, 1988
    Date of Patent: September 18, 1990
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Rokutanzono, Yukio Ide, Hiroshi Nagame, Kouichi Ohshima, Narihito Kojima, Shinji Nosho
  • Patent number: 4702979
    Abstract: This invention relates to a method of forming an image, characterized by applying voltage on a photosensitive material having a photoconductive layer and an electroconductive layer on a substrate in such a manner as to make said electroconductive layer positive and said photoconductive layer negative while irradiating optical information on said positive electroconductive layer or said negative photoconductive layer, thereby causing an anodic ion reaction on the interface between said electroconductive layer and said photoconductive layer to selectively change the spectral absorption properties of at least one of said electroconductive layer and said photoconductive layer depending on the irradiated optical information; said photosensitive material comprising an electroconductive layer of metal as a simple substance, its alloy or its metal compound applied on a substrate and a photoconductive layer overlaid on said electroconductive layer.
    Type: Grant
    Filed: July 24, 1986
    Date of Patent: October 27, 1987
    Assignee: Ricoh Co., Ltd.
    Inventors: Satoshi Otomura, Narihito Kojima