Patents by Inventor Takahiro Bito

Takahiro Bito 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: 6066423
    Abstract: A toner for electrophotography includes a binder resin as the main component and a coloring agent, wherein the binder resin contains a low molecular weight polypropylene as a separating agent, encapsulated therein; the acid value of the binder resin is adjusted equal to 1.0 (mgKOH/g) or below; and the coloring agent has a surface which is not oxidation treated and presents a pH of 7.0 or higher. Limiting the added amount and the diameter of encapsulated and dispersed polypropylene wax provides prevention against both the setoff and filming phenomena.
    Type: Grant
    Filed: March 11, 1999
    Date of Patent: May 23, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tatsuo Imafuku, Toshihisa Ishida, Yoshinori Urata, Takahiro Bito, Nobuyasu Honda
  • Patent number: 6004713
    Abstract: A process for preparing a toner includes forming a melt-kneaded mixture by mixing a raw material mixture containing a quaternary ammonium salt compound at a temperature ranging from (M-7).degree. C. to (M+7).degree. C., where M is a melting point of the quaternary ammonium salt compound, with a kneading device having a discharge port whose temperature is set lower than a temperature at which a melt viscosity of the melt-kneaded mixture at the discharge port is not higher than 10,000 Pa.a, removing the melt-kneaded mixture from the kneading device, rolling out the melt-kneaded mixture to a thickness ranging from 1.2 mm to 3.0 mm, and cooling down the melt-kneaded mixture. With the use of the toner produced by this process, the amount of charge during copying is retained in an appropriate range irrespectively of the working atmosphere and conditions of use, thereby maintaining a good image density.
    Type: Grant
    Filed: March 26, 1998
    Date of Patent: December 21, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshinori Urata, Hitoshi Nagahama, Yasuharu Morinishi, Satoshi Ogawa, Toshihisa Ishida, Tadashi Nakamura, Takahiro Bito
  • Patent number: 5983055
    Abstract: A photosensitive element is produced with a minimum amount of a conductive synthetic resin material. A draft for injection molding is formed in the inner circumferential surface as a supporting body, and a driven member provided with a gear is fixed to the end of the supporting body with a smaller inner diameter, that is, the thicker end. A driven portion in which a plurality of projections and depressions are formed alternately to be adjacent to each other in the circumferential direction is arranged on an axial end of a cylindrical supporting body made of a conductive synthetic resin, including a photosensitive layer on the outer circumferential surface. By a joint member removably engaged with the driven portion, the supporting body is rotated around the axis. In one arrangement, only the end of the supporting body is solid. In another arrangement, the supporting body is solid in the almost entire length in the axial direction.
    Type: Grant
    Filed: March 14, 1997
    Date of Patent: November 9, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahiro Bito, Syouichi Fujita, Kouichi Takenouchi, Teruhiko Noguchi, Yukihisa Imaue, Tatsuya Itou, Ken Yamagishi, Keizo Kitamura, Tadayuki Sawai