Granted Patent
Utility
US 4,982,199 · App. 07/420,604
Method and apparatus for gray scale printing with a thermal ink jet pen
Inventor:
John Dunn
Patented Case
View Patent ↗
Granted: Jan 1, 1991
Filed: Oct 4, 1989
Inventor
John Dunn
Assignee (at issue)
Hewlett-Packard Company, L.P.
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.