Granted Patent
Utility
US 4,587,621 · App. 06/500,758
Device for electrical variable magnification of document image
Inventor:
Dale R. DuVall
Patented Case
View Patent ↗
Granted: May 6, 1986
Filed: Jun 3, 1983
Inventor
Dale R. DuVall
Assignee (at issue)
The Mead Corporation
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.