Patents by Inventor Hideotoshi Hamamoto

Hideotoshi Hamamoto 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).

  • Water-based ink composition for ball-point pen
    Patent number: 5062890
    Abstract: A water-based ink composition for a ball-point pen comprises: a colorant selected from dyes or pigments; a water-soluble organic solvent; water; and a metal salt and/or an amine salt of N-acyl sarcosine. This ink can effectively prevent the wear of a ball seat of the pen caused by the rotation of a ball of the same to make it possible to keep good ink-discharging properties of the pen, whereby a smooth writing of the pen can be performed.
    Type: Grant
    Filed: October 16, 1989
    Date of Patent: November 5, 1991
    Assignee: Pentel Kabushiki Kaisha
    Inventors: Hiroshi Miyashita, Hideotoshi Hamamoto, Shigeru Nagai, Makoto Yamaguchi, Onuki Isao, Hiroshi Takahashi, Atsushi Ishiguro