Patents by Inventor Shigeharu Onuma

Shigeharu Onuma 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: 5204202
    Abstract: An electrophotographic photosensitive element, e.g. for a photocopier or laser printer, comprises a substrate and a plurality of layers on the substrate including a photoconductive layer of a-Si:H and a protective and lubricating layer which is outermost from said substrate. To provide wear resistance and long life-time of the protective and lubricating layer, this layer comprises a microporous solid material having a pore structure which extends substantially over the whole thickness of the material and a hydrophobic lubricant carried by said solid material. The lubricant includes a liquid film and often times a non-particulate solid film, and provides at least part of the outer surface of the element and is present also in the pores of said microporous solid material.
    Type: Grant
    Filed: March 16, 1990
    Date of Patent: April 20, 1993
    Assignees: Hitachi, Ltd., Hitachi Chemical Co., Ltd.
    Inventors: Fuminori Ishikawa, Kunihiro Tamahashi, Shigeharu Onuma, Masatoshi Wakagi, Masanobu Hanazono, Mitsuyoshi Shoji, Takayuki Nakakawaji, Yutaka Ito, Shigeki Komatsuzaki, Chiaki Yamabishi
  • Patent number: 5073466
    Abstract: An electrophotographic member comprising a support, a photoconductive layer formed thereon, and a surface layer formed thereon, said surface layer including or attaching a lubricating agent having a perfluoropolyoxyalkyl or perfluoropolyoxyalkylene group to form an organic surface protective lubricating layer, and a fixing group to be fixed to the surface layer, is excellent in moisture resistance, wear resistance and cleaning properties and thus useful in an electrophotographic apparatus with a long life and high reliability.
    Type: Grant
    Filed: August 16, 1989
    Date of Patent: December 17, 1991
    Assignees: Hitachi, Ltd., Hitachi Chemical Company, Ltd.
    Inventors: Fuminori Ishikawa, Kunihiro Tamahashi, Shigeharu Onuma, Masatoshi Wakagi, Masanobu Hanazono, Mitsuyoshi Shoji, Takayuki Nakakawaji, Yutaka Ito, Shigeki Komatsuzaki, Yasuo Shimamura, Chiaki Yamagishi
  • Patent number: 4791040
    Abstract: The photoconductive layer (3) has a triple-layer structure comprised of an upper layer (33) made of amorphous silicon containing germanium and carbon, a middle layer (32) made of amorphous silicon containing germanium, and a lower layer (31) made of amorphous silicon. The upper layer (33) formed between a surface layer (4) and the middle layer (32), and the lower layer (31) formed between the middle layer (32) and a barrier layer (2) serve to reduce the energy difference and the interfacial state between respective layers thus, high electrophotographic sensitivity for a longer wavelength light can be obtained, and sensitivity in the oscillation wavelength of a GaAlAs diode laser improves effectively.
    Type: Grant
    Filed: April 20, 1987
    Date of Patent: December 13, 1988
    Assignees: Hitachi Ltd., Hitachi Chemical Company, Ltd.
    Inventors: Makoto Fujikura, Toshiyuki Ohno, Shigeharu Onuma, Kunihiro Tamahashi, Mitsuo Chigasaki, Yasuo Shimamura
  • Patent number: 4430404
    Abstract: An electrophotographic photosensitive material having a long lifetime can be provided by forming an amorphous silicon layer having a thickness of 0.01-0.08 .mu.m on the photoconductive layer on the electrically conductive substrate in the said material without changing the characteristics of the photoconductive layer.
    Type: Grant
    Filed: April 26, 1982
    Date of Patent: February 7, 1984
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Akira Hosoya, Kunihiro Tamahashi, Shigeharu Onuma, Atsushi Kakuta, Yasuki Mori, Katsuhito Suzuki, Hirosada Morishita
  • Patent number: 4405703
    Abstract: In an electrophotographic plate comprising a substrate and a photoconductive layer formed on said substrate, when said substrate is made of an age-hardening type aluminum alloy and has a Vickers hardness of 60 Hv or higher, there can be produced electrophotographic plates high in dimensional accuracy, good in resistance to mechanical damages and impact, and very small in eccentricity when molded in the form of a drum. When the surface hardness of the selenium photoconductive layer is made 5 H or harder in pencil hardness, the resulting electrophotographic plate is excellent in printing performance and has a long life.
    Type: Grant
    Filed: September 30, 1981
    Date of Patent: September 20, 1983
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Shigeharu Onuma, Kunihiro Tamahashi, Akira Hosoya, Atsushi Kakuta, Yasuki Mori, Hirosada Morishita