Granted Patent
Utility
US 4,977,943 · App. 07/349,080
Waste paper de-inking process using multi-stage vertical column vapor-liquid mixer
Inventor:
Noriji Miyabe
Patented Case
View Patent ↗
Granted: Dec 18, 1990
Filed: May 9, 1989
Inventor
Noriji Miyabe
Assignee (at issue)
Jujo Paper Co., Ltd.
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.