Granted Patent
Utility
US 4,957,841 · App. 07/407,225
Specifically influencing the triboelectric effect of azo pigments
Inventors:
Hans-Tobias Macholdt, Alexander Sieber, Franz Schui, Reinhold Deubel
Patented Case
View Patent ↗
Granted: Sep 18, 1990
Filed: Sep 14, 1989
Inventors
Hans-Tobias Macholdt
Alexander Sieber
Franz Schui
Reinhold Deubel
Assignee (at issue)
Hoechst GmbH
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.