Patents by Inventor Yasuhiro Ohya

Yasuhiro Ohya 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).

  • Two component electrophotographic developer
    Patent number: 4880719
    Abstract: An electrophotographic two-component system developer is described, comprising a positive charging toner and a negative charging carrier of the dispersed magnetic powder type, wherein a hydrophilic alumina particle is adhered onto the surface of said positive charging toner and a negative charging carrier has a volume average particle diameter of from 30 to 80 .mu.m. The developer provides reduced toner cloud upon development processing and provides toner images free from fog.
    Type: Grant
    Filed: June 29, 1988
    Date of Patent: November 14, 1989
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Toshiaki Murofushi, Hiroshi Nakazawa, Koichi Oyamada, Shigeo Aonuma, Yoshimi Amagai, Yasuhiro Ohya
  • Electrophotographic developer containing positively chargeable toner
    Patent number: 4837100
    Abstract: A positively chargeable electrophotographic developer is disclosed, comprising a carrier, toner particles positively chargeable by friction with the carrier, fine particles of hydrophilic alumina, and fine particles of one of tin oxide, hydrophobic silica and titanium dioxide. The developer hardly undergoes toner cloud or toner dropping during development and suffers neither extreme deterioration in charging properties nor fog formation even when used for taking a large number of copies.
    Type: Grant
    Filed: September 29, 1987
    Date of Patent: June 6, 1989
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Toshiaki Murofushi, Yasuhiro Ohya, Hiroshi Nakazawa, Koichi Oyamada