Granted Patent
Utility
US 5,286,863 · App. 07/809,898
Oxidation process for preparing quinacridone pigments
Inventors:
Fridolin Babler, Edward E. Jaffe
Patented Case
View Patent ↗
Granted: Feb 15, 1994
Filed: Dec 18, 1991
Inventors
Fridolin Babler
Edward E. Jaffe
Assignee (at issue)
Ciba-Geigy
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.