Patents by Inventor Toshiro Yamakawa

Toshiro Yamakawa 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: 4535049
    Abstract: Disclosed is a pressure-fixing toner for the electrophotography, which comprises electroscopic particles having an indeterminate shape and comprising as a pressure-fixing binder component a composite binder component comprising a wax component and a resin component composed mainly of a styrene-acrylic copolymer at a weight ratio of from 54/46 to 20/80, wherein the wax component is present in the form of spherical particles having a particle size smaller than 10 microns in a continuous phase of the resin component.
    Type: Grant
    Filed: August 2, 1983
    Date of Patent: August 13, 1985
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Nobuyasu Honda, Toshiro Yamakawa, Toshimitsu Ikeda
  • Patent number: 4517274
    Abstract: Disclosed is a method for developing electrostatic latent images, which comprises frictionally contacting the surface of a substrate having an electrostatic latent image formed thereon with a magnetic brush of a developer formed on a developer-delivering sleeve having a magnet disposed therein, wherein a magnetic brush is formed on the sleeve with an earing promoting component comprising sintered ferrite particles having a particle size of 20 to 100 microns and a developer component comprising particles of a dispersion of a magnetic powder in a binder medium having a particle size of 5 to 50 microns.
    Type: Grant
    Filed: August 30, 1983
    Date of Patent: May 14, 1985
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Nobuyasu Honda, Toshiro Yamakawa, Toshimitsu Ikeda
  • Patent number: 4495267
    Abstract: Disclosed is a magnetic toner having an improved humidity dependency, which comprises as main ingredients a magnetic material composed of magnetite and a binder medium, wherein the water-soluble component content in the magnetite is lower than 0.15% by weight and the water content of the magnetite at a temperature of 20.degree. C. and a relative humidity of 60% is lower than 0.3% by weight.If this magnetic toner is used for developing an electrostatically charged image, a sharp and clear copy having a high image density with no fogging can be obtained even under a high humidity condition.
    Type: Grant
    Filed: March 22, 1983
    Date of Patent: January 22, 1985
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Nobuyasu Honda, Toshiro Yamakawa, Toshimitsu Ikeda