Granted Patent
Utility
US 4,668,291 · App. 06/516,387
Method for the production of a dispersion of colorless chromogenic material
Inventors:
Takuji Tuji, Shuki Okauchi
Patented Case
View Patent ↗
Granted: May 26, 1987
Filed: Jul 22, 1983
Inventors
Takuji Tuji
Shuki Okauchi
Assignee (at issue)
Kanzaki Paper Manufacturing Co., Ltd.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.