Patents by Inventor Hidemi Uematsu

Hidemi Uematsu 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).

  • Fluorine-containing graft copolymer and toner using the same
    Patent number: 5328794
    Abstract: A fluorine-containing graft copolymer prepared by a step (i) of polymerizing a monomer having formula (I) and an unsaturated carboxylic acid or a monomer having a glycidyl group to obtain a copolymer, ##STR1## wherein R represents --H or --CH.sub.3 group; and A represents --COOC.sub.n H.sub.2n+1 or OC.sub.n H.sub.2n+1, in which n is an integer of 6 to 20; a step (ii) of esterifying the resulting copolymer by using a monomer having a glycidyl group in the case where a constituting monomer of the above copolymer is an unsaturated carboxylic acid, or by using an unsaturated carboxylic acid in the case where a constituting monomer of the above copolymer is a monomer having a glycidyl group; and a step (iii) of graft-polymerizing a monomer comprising at least fluoroalkyl acrylate or fluoroalkyl methacrylate on the above esterified copolymer. In addition, a toner comprising a coloring agent and a resin component which comprises the above-mentioned fluorine-containing graft copolymer is disclosed.
    Type: Grant
    Filed: March 16, 1993
    Date of Patent: July 12, 1994
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsubuko Kazuo, Shinichi Kuramoto, Kazuhiko Umemura, Toshihiko Takahashi, Hidemi Uematsu
  • Method for producing a vinyl resin using a silicon oil solvent
    Patent number: 5189102
    Abstract: A method for producing a vinyl resin comprising the steps of dissolving or dispersing a polymerizable vinyl monomer in a polymerization solvent containing a silicone oil, and polymerizing the polymerizable vinyl monomer in the presence of a polymerization catalyst.
    Type: Grant
    Filed: March 4, 1992
    Date of Patent: February 23, 1993
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuo Tsubuko, Shinichi Kuramoto, Kazuhiko Umemura, Hidemi Uematsu, Okawara, Makoto
  • Liquid developer for image fixing method using heat application rollers
    Patent number: 5169739
    Abstract: A liquid developer comprises an aliphatic hydrocarbon carrier liquid and a toner dispersed in the carrier liquid, which toner comprises a coloring agent and a resin component, wherein a solid toner component which is obtained by evaporating the liquid developer to dryness has a softening point of 60.degree. C. to 90.degree. C. and flow-initiating point of 110.degree. C. to 160.degree. C.
    Type: Grant
    Filed: February 13, 1990
    Date of Patent: December 8, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiko Umemura, Kazuo Tsubuko, Shinichi Kuramoto, Toshihiko Takahashi, Hidemi Uematsu
  • Toner for electrophotography including fluorine contained graft copolymer
    Patent number: 5061587
    Abstract: A toner for developing latent electrostatic images comprising a coloring agent and a fluorine-contained graft copolymer which is prepared by grafting a fluorine-contained monomer to a main polymer comprising a repeating unit represented by formula (I): ##STR1## wherein R and R' each independently represent H or CH.sub.3, and m represent san integer of 1 to 20.
    Type: Grant
    Filed: October 13, 1989
    Date of Patent: October 29, 1991
    Assignee: Ricoh Company Ltd.
    Inventors: Kazuo Tsubuko, Shinichi Kuramoto, Kazuhiko Umemura, Hidemi Uematsu