Patents by Inventor Shinichi Kuramoto

Shinichi Kuramoto 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: 5370959
    Abstract: An image formation method of developing a latent electrostatic image formed on a latent-electrostatic-image bearing member to a visible toner image by a one-component type developer consisting essentially of a toner is carried out by the steps of forming numerous micro closed electric fields near the surface of a developer-bearing member by causing the developer-bearing member to selectively hold electric charges on the surface thereof; supplying the developer to the surface of the developer-bearing member to hold the toner on the surface of the developer-bearing member by the micro closed electric fields; and developing a latent electrostatic image to a visible toner image by the toner. The toner is composed of a binder resin, a coloring agent and a quaternary ammonium salt serving as a charge controlling agent.
    Type: Grant
    Filed: March 23, 1992
    Date of Patent: December 6, 1994
    Assignee: Ricoh Company, Ltd.
    Inventors: Tomoe Hagiwara, Shinichi Kuramoto, Motoi Orihara
  • 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
  • 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
  • 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
  • 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
  • Patent number: 5026621
    Abstract: A toner for electrophotography is disclosed, which comprises as the main components a coloring component and a binder resin which is a block copolymer comprising a functional segment (A) consisting of at least one of a fluoralkyl acryl ester block unit or a fluoralkyl methacryl ester block unit, and a compatible segment (B) consisting of a fluorine-free vinyl or olefin monomer block unit.
    Type: Grant
    Filed: May 12, 1989
    Date of Patent: June 25, 1991
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuo Tsubuko, Shinichi Kuramoto, Kazuhiko Umemura, Makoto Ohkawara
  • Patent number: 4957842
    Abstract: The present invention relates to a liquid developer for electrostatic latent images which comprises a toner comprising a colorant and a binding agent as the main components dispersed in an aliphatic hydrocarbon carrier liquid, characterized in that said colorant is prepared by using a yellow dye or pigment having the following general formula (I), ##STR1## (wherein X and Y represent --H, --OCH.sub.3, --Cl, --CH.sub.3, --CH.sub.2 CH.sub.3, --CH.sub.2 CH.sub.2 CH.sub.3, --OCH.sub.2 CH.sub.3, --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.3 or --OCH.sub.2 CH.sub.2 CH.sub.3).
    Type: Grant
    Filed: October 23, 1986
    Date of Patent: September 18, 1990
    Assignee: Ricoh Co., Ltd.
    Inventors: Toshiyuki Fukase, Yoshihiro Sugiyama, Hazime Takanashi, Kazuo Tsubuko, Shinichi Kuramoto
  • Patent number: 4925763
    Abstract: A developer for electrophotography is disclosed, which comprises toner particles containing therein at least an ionomer resin, which toner particles may comprise a colorant which is prepared by a flushing method by using a pigment component and an ionomer resin, when necessary, with addition thereto a humic acid component selected from the group consisting of humic acid, a salt of humic acid, and a humic acid derivative.
    Type: Grant
    Filed: March 11, 1988
    Date of Patent: May 15, 1990
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuo Tsubuko, Shinichi Kuramoto, Kiyoshi Sakai
  • Patent number: 4860050
    Abstract: A developing replenisher material or a replenisher liquid developer to be supplied to a developer tank of an electrostatic copying machine comprises 1000 parts by weight of a carrier liquid composed mainly of aliphatic hydrocarbon and 200 or 1200 parts by weight of toner particles composed mainly of a binder resin and a pigment. The toner concentration of the replenisher liquid developer is high enough to prevent an overflow from the developer tank, allow many copies to be produced by the copying machine, and prevent a solvent shock. The toner particles, when added to the carrier liquid, can immediately and well be dispersed in the carrier liquid.
    Type: Grant
    Filed: July 28, 1987
    Date of Patent: August 22, 1989
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsuneo Kurotori, Manabu Mochizuki, Kenzo Ariyama, Shinichi Kuramoto, Yoshihiro Sugiyama, Hajime Takanashi, Takashi Ishizuka, Yoshio Kudo, Yoshio Sato
  • Patent number: 4764447
    Abstract: This invention relates to a non-aqueous type resin dispersion obtained by polymerizing a polymerizable composition containing at least monomer A represented by the general formula (I), ##STR1## (wherein, R.sup.1 represents --H or --CH.sub.3, X represents --COOC.sub.n H.sub.2n+1 or --OCOC.sub.n H.sub.2n+1, and n represents an integer of 6-20), monomer B represented by the general formula (II), ##STR2## (wherein, R.sup.2 and R.sup.3 represent --H or --CH.sub.3 and m represents an integer of 1-20), and monomer C having a carboxyl group or a glycidyl group in the presence of a polymerization initiator in an aliphatic hydrocarbon solvent.
    Type: Grant
    Filed: July 8, 1986
    Date of Patent: August 16, 1988
    Assignee: Ricoh Co., Ltd.
    Inventors: Kazuo Tsubuko, Shinichi Kuramoto, Kayoko Nagai, Makoto Okawara, Hajime Takanashi
  • Patent number: 4618558
    Abstract: A liquid developer for use in electrostatic photography which comprises further containing wax in toner particles consisting essentially of a colorant and a resin as well as mixing with and including among the wax-containing toner particles a filler for preventing transfer-crush comprising particles in the range of 10-20.mu. particle diameter 63.5 piece % or more, particles over 20.mu. particle diameter 6.5 piece % or less and particles not more than 10.mu. particle diameter 30 piece % or less is capable of forming high quality images, irrespective of whether the smoothness of a transfer paper used is high or low.
    Type: Grant
    Filed: October 30, 1984
    Date of Patent: October 21, 1986
    Assignee: Ricoh Co., Ltd.
    Inventors: Shinichi Kuramoto, Hajime Takanashi
  • Patent number: 4388395
    Abstract: A liquid developer for use in electrophotography is disclosed which is prepared by dispersing a toner consisting essentially of a pigment or dye and a resin in a carrier liquid having a high insulating property and a low dielectric constant, wherein said resin is a nonaqueous dispersed resin obtained by effecting, in a nonaqueous solvent comprising an aliphatic hydrocarbon, the steps of:(a) copolymerizing (1) a monomer A having the general formula I: ##STR1## [wherein R is H or --CH.sub.3, and A is --COOC.sub.n H.sub.2n+1 or --OC.sub.n H.sub.
    Type: Grant
    Filed: January 15, 1982
    Date of Patent: June 14, 1983
    Assignee: Ricoh Co., Ltd.
    Inventors: Kazuo Tsubuko, Junichiro Hashimoto, Shinichi Kuramoto, Makoto Okawara