Granted Patent
Utility
US 4,449,837 · App. 06/305,763
Ribbon cartridge with back check
Inventor:
James A. Craft
Patented Case
View Patent ↗
Granted: May 22, 1984
Filed: Sep 25, 1981
Inventor
James A. Craft
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.