Patents by Inventor Eiji Wasai

Eiji Wasai 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: 5929135
    Abstract: This invention provides a ball-point pen suited to low-viscosity aqueous ink. This ball-point pen includes a ball-point pen refill in which an ink reservoir communicates with a tip for holding a tip ball via a joint, wherein the ink reservoir is filled with water type ball-point pen ink containing at least one type of a solvent selected from the group consisting of ethyleneglycol, diethyleneglycol, propyleneglycol, and glycerin in an amount of 5 to 40 wt % of the total ink amount, a crosslinking acrylic acid polymer in an amount of 0.1 to 1.0 wt % of the total ink amount, a pigment in an amount of 5 to 10 wt % of the total ink amount, and the balance primarily consisting of water, and the tip has a spring which in a normal state urges and brings the tip ball into intimate contact with the inner edge of a ball holding portion at the front end of the tip and releases the intimate contact when writing is performed.
    Type: Grant
    Filed: July 3, 1997
    Date of Patent: July 27, 1999
    Assignee: Mitsubishi Pencil Kabushiki Kaisha
    Inventors: Eiji Wasai, Kazuhiko Furukawa