Patents by Inventor Tooru Ishijima

Tooru Ishijima 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: 5980765
    Abstract: Using a newly developed composite ceramics material suited for balls of ball-point pens, a method of manufacturing composite ceramics balls for ball-point pens that have affinity for both oil-based ink and water-based ink is provided. In this method, the composite ceramics, whose main components are mullite (3Al.sub.2 O.sub.3 .multidot.2SiO.sub.2) and zirconia (ZrO.sub.2) at the ratio of 50-95% to 5-50% by weight, is polished into mirror-finished balls and then chemical processing or physical processing is performed on the ball surfaces to form indentations in the ball surfaces. The chemical processing is preferably an etching using hydrofluoric acid, and the degree of indentations can be controlled by changing the concentration of hydrofluoric acid and the duration of etching.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: November 9, 1999
    Assignee: Ohto Kabushiki Kaisha
    Inventors: Takao Machida, Tooru Ishijima