Granted Patent
Utility
US 4,579,809 · App. 06/541,617
Positive image formation
Inventor:
Edward Irving
Patented Case
View Patent ↗
Granted: Apr 1, 1986
Filed: Oct 13, 1983
Inventor
Edward Irving
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.