Patents by Inventor Koji Tsukahara

Koji Tsukahara 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).

  • Polygon scanner and production process thereof
    Patent number: 5606448
    Abstract: A polygon scanner has a lighter rotating shaft on which a polygon mirror is mounted, to prevent a positional deviation of the polygon mirror from the rotating shaft in high speed rotation, in which the rotating shaft is supported through a dynamic pressure air bearing on a fixed shaft, in which the polygon mirror and motor constituent members are mounted on the rotating shaft, and in which the rotating shaft and the polygon mirror are made of respective light weight materials matched with each other in coefficient of thermal expansion, for example of aluminum or an aluminum alloy. Further, an anodic oxide film is formed at least on a portion where the rotating shaft could contact with the fixed shaft, and floating means is provided for constantly floating the rotating shaft relative to the fixed shaft upward in an axial direction thereof.
    Type: Grant
    Filed: March 23, 1993
    Date of Patent: February 25, 1997
    Assignees: Ricoh Company, Ltd., Tohoku Ricoh Co., Ltd.
    Inventors: Mitsuo Suzuki, Yukio Itami, Yoshio Hashimoto, Koji Tsukahara, Yoshihiro Takahashi, Takao Abe
  • Polygon scanner and production process thereof
    Patent number: 5574591
    Abstract: A polygon scanner has a lighter rotating shaft on which a polygon mirror is mounted, to prevent a positional deviation of the polygon mirror from the rotating shaft in high speed rotation, in which the rotating shaft is supported through a dynamic pressure air bearing on a fixed shaft, in which the polygon mirror and motor constituent members are mounted on the rotating shaft, and in which the rotating shaft and the polygon mirror are made of respective light weight materials matched with each other in coefficient of thermal expansion, for example of aluminum or an aluminum alloy. Further, an anodic oxide film is formed at least on a portion where the rotating shaft could contact with the fixed shaft, and floating means is provided for constantly floating the rotating shaft relative to the fixed shaft upward in an axial direction thereof.
    Type: Grant
    Filed: February 6, 1995
    Date of Patent: November 12, 1996
    Assignees: Ricoh Company, Ltd., Tohoku Ricoh Co., Ltd.
    Inventors: Mitsuo Suzuki, Yukio Itami, Yoshio Hashimoto, Koji Tsukahara, Yoshihiro Takahashi, Takao Abe