3-heteroaramatic-substituted acrylonitrile compounds as co-developers for black-and-white photothermographic and thermographic elements

Granted: Jun 3, 1997 Filed: May 16, 1996

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.