Patents by Inventor Hisatomo Sato

Hisatomo Sato 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: 5573881
    Abstract: A toner composition for electrophotography comprises at least a binder, a coloring agent and optionally a low molecular weight wax in an amount ranging from 0.5 to 20 parts by weight per 100 parts by weight of the binder as essential components wherein the binder comprises, as a principal component, a resin mixture prepared by heating a resin solution comprising a styrene resin and a block copolymer which comprises blocks derived from at least one member selected from ethylenic hydrocarbons and conjugated diene hydrocarbons and blocks derived from styrene and/or a hydrogenated product thereof in an amount ranging from 0.1 to 20 parts by weight per 100 parts by weight of the styrene resin to remove the solvent. The low molecular weight wax may be included in the binder.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: November 12, 1996
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Shoji Kawasaki, Nobuhiro Hirayama, Kenji Uchiyama, Hisatomo Sato, Hiromi Akiyama, Katuo Uramoto
  • Patent number: 5389483
    Abstract: The present invention provides electrophotographic toner which comprises as a principal component a mixture of 20-80 parts by weight of a first ethylene polymer (X) whose weight-average molecular weight (Mw) is at least 200,000 and a second ethylene polymer (Y) whose Z average molecular weight/number-average molecular weight (Mz/Mn) is at least 6 and Mw is not greater than 50,000. According to this invention, electrophotographic toner of wide non-offset range can be obtained and, images of stable quality in a low heat quantity, which have not been attained by the prior art, can be obtained.
    Type: Grant
    Filed: June 9, 1993
    Date of Patent: February 14, 1995
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Shoji Kawasaki, Nobuhiro Hirayama, Kenji Uchiyama, Hisatomo Sato, Hiromi Akiyama
  • Patent number: 5266434
    Abstract: The present invention provides an electrophotographic toner composition comprising a binder and a colorant. At least 70 wt. % of the binder are soluble in THF, the number average molecular weight (Mn) and Z average molecular weight (Mz) of the THF-soluble portion of the binder as measured using THF are 2,000-15,000 and at least 400,000, respectively. The particle size of the binder has been controlled so that D.sub.75 is not greater than 2.5 mm, D.sub.25 not smaller than 0.15 mm and D.sub.75 /D.sub.25 at least 1.5. The toner composition does not have variations from one lot to another. The quantity of electricity to be charged during a copying operation changes little. The picture quality can be maintained constant even during a long-time copying operation.
    Type: Grant
    Filed: August 6, 1991
    Date of Patent: November 30, 1993
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Nobuhiro Hirayama, Kenji Uchiyama, Shoji Kawasaki, Hisatomo Sato, Hiromi Akiyama
  • Patent number: 5230978
    Abstract: Disclosed herein is an electrophotographic toner composition produced by using a low-melt-viscosity and high-strength resin. The present invention provides a toner which fixes at low heat and has high strength and therefore, is suitable for high-speed copying machines and lower-heat copying machines. The resultant benefits of the present invention are that the lowest limit of the fixing temperature is low, non-offset range is wide and picture properties are good. The electrophotographic toner composition can, therefore, provide stable pictures even when fixed at low heat.
    Type: Grant
    Filed: August 14, 1991
    Date of Patent: July 27, 1993
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Shoji Kawasaki, Nobuhiro Hirayama, Kenji Uchiyama, Hisatomo Sato, Hiromi Akiyama
  • Patent number: 4849316
    Abstract: Resin composition containing vinyl polymer and olefin polymer for use in electrophotography, electrostatic recording and electrostatic printing and the like, more particularly the resin composition obtained by uniformly dispersing the olefin polymer in the vinyl polymer, and the toner containing this resin composition are disclosed.
    Type: Grant
    Filed: December 13, 1988
    Date of Patent: July 18, 1989
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Shoji Kawaski, Hisatomo Sato, Masaaki Shin, Takashi Yamamoto
  • Patent number: 4833057
    Abstract: Disclosed is a toner composition for the electrophotography, which comprises as a main component a urethane-modified polyester resin obtained by reacting a polyester resin with an isocyanate compound, in which the mole-equivalent ratio between the hydroxyl group of the polyester resin and the isocyanate group of the isocyanate compound is within a specific range and the glass transition temperature of the obtained resin is within a specific range.This composition has a good fixing property at a low temperature and a good offset resistance at a high temperature, and this composition is especially excellent in the form of a mixture with a polymer having a relatively low molecular weight.
    Type: Grant
    Filed: September 22, 1987
    Date of Patent: May 23, 1989
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Akira Misawa, Hisatomo Sato, Keiichi Ishikawa, Masaaki Shin, Akio Fujiwara, Kazuo Hisamatsu, Shoji Kawasaki, Kenji Uchiyama