Patents by Inventor Takahumi Toyama

Takahumi Toyama 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).

  • Chromogenic fluoran derivatives
    Patent number: 4677203
    Abstract: Certain 3-piperidino fluoran derivatives useful as color recording materials are disclosed.
    Type: Grant
    Filed: June 14, 1983
    Date of Patent: June 30, 1987
    Assignee: Shin Nisso Kako Co., Ltd.
    Inventors: Masakichi Yahagi, Shoichi Horiuchi, Takahumi Toyama, Akio Kashiwagi, Teruo Suzuki, Tetsuo Igaki, Kazuyuki Horisawa, Mituhiro Shoji
  • Chromogenic fluoran derivatives and the preparation and use thereof
    Patent number: 4410708
    Abstract: Certain 3-substituted amino-7-substituted fluoran derivatives useful as color recording materials.
    Type: Grant
    Filed: February 3, 1976
    Date of Patent: October 18, 1983
    Assignee: Shin Nisso Kako Co., Ltd.
    Inventors: Masakichi Yahagi, Shoichi Horiuchi, Takahumi Toyama, Akio Kashiwagi, Teruo Suzuki, Tetsuo Igaki, Kazuyuki Horisawa, Mituhiro Shoji
  • Chromogenic fluoran derivatives and the preparation and use thereof
    Patent number: 3959571
    Abstract: A recording material which is suitable as a pressure-sensitive or heat-sensitive copying paper or recording paper by developing a color in contact with an electron-accepting material which comprises certain fluoran derivatives containing piperidino, pyrrolidino, morpholino and cycohexylamino groups.
    Type: Grant
    Filed: May 21, 1974
    Date of Patent: May 25, 1976
    Assignee: Shin Nisso Kako Co., Ltd.
    Inventors: Masakichi Yahagi, Shoichi Horiuchi, Takahumi Toyama, Akio Kashiwagi, Teruo Suzuki, Tetsuo Igaki, Kazuyuki Horisawa, Mituhiro Shoji