Patents by Inventor Keijiro Yagi

Keijiro Yagi 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).

  • Electrophotographic image fixing device avoiding offset in the image by means of differential roller speed
    Patent number: 5481349
    Abstract: An electrophotographic image fixing device having preventing offsetting and affording images of high quality is provided. The electrophotographic image fixing device has a heating roller 1, made up of a mandrel 5 and an elastic layer 4 of 40-60.degree. in hardness, as measured by a spring type hardness meter of JIS K6301, provided on the mandrel, and a pressure roller 2, arranged in contact with the heating roller 1 and having a surface layer 6 the hardness of which is equal to or higher than the hardness of the elastic layer 4 of the heating roller 1. A heater 8 is provided for heating and fusion-depositing a toner image onto a toner substrate 3, by passing through the nip portion between the two rollers the toner substrate 3 on which the toner image has been formed. The linear speed of the surface of the pressure roller is 1.005-1.05 times that of the surface of the heating roller.
    Type: Grant
    Filed: December 10, 1993
    Date of Patent: January 2, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Toshiya Satoh, Akiko Oikawa, Katsuyoshi Onose, Keijiro Yagi, Tomoji Kitagishi