Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4954631 | Fluoran compounds and color forming recording materials using same | Takeo Obitsu, Yutaka Ohnishi, Shinji Yoshinaka, Mitsuhiro Yanagita, Nobuyuki Hirai | 1990-09-04 |
| 4826806 | Fluoran compounds and color forming recording materials using same | Takeo Obitsu, Yutaka Ohnishi, Shinji Yoshinaka, Mitsuhiro Yanagita, Nobuyuki Hirai | 1989-05-02 |
| 4794069 | Spirobenzanthracene phthalide compounds, processes for preparing same and color forming recording materials containing said compounds | Yutaka Ohnishi, Shinji Yoshinaka, Toshiyuki Tanaka, Takeo Obitsu | 1988-12-27 |