Patents by Inventor Ritsuko Doi

Ritsuko Doi 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).

  • Jet ink and process for preparing dispersion of colored fine particles for jet ink
    Patent number: 6074467
    Abstract: An aqueous jet ink which is provided with a long-term dispersion stability, a stable emission property as a ink-jet stream, and good adhesion of printed images to the recording medium. The present jet ink is constituted as an aqueous liquid dispersion of fine color particles which are formed by coating fine pigment particles (a) with a coat forming resin having carboxyl groups (b). The surface of the color particles is covered with the quaternary carboxyl groups in a form of quaternary ammonium salt and the average volume diameter of the fine color particles is restricted to less than 0.5 .mu.m. An increase rate of the average volume diameter of the fine color particles when the dried ink is dispersed again in water is also restricted to less than 50%.
    Type: Grant
    Filed: May 11, 1998
    Date of Patent: June 13, 2000
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Isao Tabayashi, Kazunari Kawai, Sadahiro Inoue, Ritsuko Doi, Norie Osawa