Patents by Inventor Toyomi Hashizume

Toyomi Hashizume 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: 6821697
    Abstract: A toner for electrostatic image development made of a polyester resin having a spherical or generally spherical shape, which allows the use of a so-called oilless fixation system capable of fixing, without employing an anti-offset solution as a heat roller fixation system, and which also provides a developed image having excellent quality. The toner comprises a binder resin and a colorant. The flow beginning temperature Tfb of the toner is 90° C. or higher and 120° C. or lower, the T1/2 temperature exceeds 120° C. and is 160° C. or lower, and the flow ending temperature T end is 130° C. or higher and 170° C. or lower. The toner has a spherical or generally spherical shape having an average roundness of 0.97 or more. The toner can be produced by phase inversion at a low shear within a range of 0.2-5 m/second employing an added alcohol solvent.
    Type: Grant
    Filed: February 26, 2001
    Date of Patent: November 23, 2004
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Hitoshi Takayanagi, Takashi Ito, Kenichi Hirabayashi, Toyomi Hashizume
  • Publication number: 20020051923
    Abstract: The present invention provides a toner for electrostatic image development made of a polyester resin having a spherical or generally spherical shape, which allows the use of a so-called oilless fixation system capable of fixing, without employing an anti-offset solution as a heat roller fixation system, and which also provides a developed image having excellent quality, and a method of producing the same. The toner for electrostatic image development comprises at least a binder resin and a colorant. The binder resin is made of a polyester resin. The flow beginning temperature Tfb of the toner, as measured by a constant load extrusion type capillary rheometer, is 90° C. or higher and 120° C. or lower, the T½ temperature exceeds 120° C. and is 160° C. or lower, and the flow ending temperature Tend is 130° C. or higher and 170° C. or lower.
    Type: Application
    Filed: February 26, 2001
    Publication date: May 2, 2002
    Applicant: DAINIPPON INK AND CHEMICALS, INC.
    Inventors: Hitoshi Takayanagi, Takashi Ito, Kenichi Hirabayashi, Toyomi Hashizume
  • Patent number: 6248491
    Abstract: The present invention provides a polyester resin toner which has good fixing properties and is superior in image quality in a heat roller fixation system without employing an anti-offset solution, and which has a spherical or generally spherical shape and has a small particle diameter, and a method of producing the same. In a toner for electrostatic image development comprising a binder resin and a colorant, said binder resin is made of a polyester resin. Furthermore, the weight-average molecular weight as measured by gel permeation chromatography of a tetrahydrofuran-soluble fraction of said polyester resin contained in the toner is 30,000 or more and the weight-average molecular weight/number-average molecular weight is 12 or more and, moreover, the area ratio of a molecular weight of 600,000 or more is 0.5% or more and the area ratio of a molecular weight of 10,000 or less is within a range of 20-80%.
    Type: Grant
    Filed: September 21, 2000
    Date of Patent: June 19, 2001
    Assignee: Dainippon Ink and Chemical Inc.
    Inventors: Hitoshi Takayanagi, Minoru Nomura, Takashi Ito, Kenichi Hirabayashi, Yukiko Soma, Toshiro Kogawara, Toyomi Hashizume, Kazuo Itoya
  • Patent number: 6017670
    Abstract: An electrophotographic toner having a volume-average particle diameter of from 3 to 15 .mu.m. The toner comprises a spherical particulate material having an average circularity of not less than 0.97 having a colorant encapsulated in a binder resin. The binder resin is a styrene-acrylic resin having an acid value of from 30 to 150 which is at least partly crosslinked. The tetrahydrofuran insoluble content in the whole of the binder resin including crosslinkd portions in the particulate material is from 0.5 to 70% by weight.
    Type: Grant
    Filed: June 4, 1998
    Date of Patent: January 25, 2000
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Toyomi Hashizume, Shoji Okuno, Yukiko Soma, Hitoshi Takayanagi, Minoru Nomura, Takashi Ito, Hiroyuki Ohminato