Patents by Inventor Hiromitsu Kawase

Hiromitsu Kawase 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).

  • Negative toner for developing latent electrostatic images
    Patent number: 5085965
    Abstract: A negatively chargeable toner for developing latent electrostatic images comprising a coloring agent, a resin component which comprises a homopolymer of a first monomer having formula (I) or a copolymer of the aforementioned first monomer and a second monomer: ##STR1## wherein R.sup.1 represents --H or --CH.sub.3 ; R.sup.2 and R.sup.3 each represent --CN, --COOH or --NO.sub.2 ; R.sup.4 represents --F, --Cl or --Br; and n is an integer of 1 to 10.
    Type: Grant
    Filed: March 20, 1990
    Date of Patent: February 4, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Toshiki Nanya, Kimitoshi Yamaguchi, Kazuo Tsubuko, Toshihiko Takahashi, Hiromitsu Kawase, Makoto Ookawara
  • Dry-type toner for electrophotography with carnauba wax
    Patent number: 5079123
    Abstract: A dry-type toner for electrophotography comprising a binder resin, a coloring agent, and, as a lubricant, a carnauba wax substantially free of free aliphatic acids. The toner may further comprise a magnetic material, and the resulting toner mixture can be used as a magnetic toner.
    Type: Grant
    Filed: May 30, 1990
    Date of Patent: January 7, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Toshiki Nanya, Kimitoshi Yamaguchi, Hiromitsu Kawase