Robert A Fleming

US Patent:

44550391, Jun 19, 1984

Filed:

Jun 24, 1982

Appl. No.:

6/391690

Inventors:

Edward H. Weitzen - Lawrence NY
Salvatore F. D'Amato - Floral Park NY
Robert M. Fleming - Weston MA
Manfred R. Kuehnle - New London NH
C. Frederick Ekman - Harvard MA
Jurgen Kruse - Branford CT
Harold J. Weber - Sherborn MA

Assignee:

Coulter Systems Corporation - Bedford MA

International Classification:

B42D 1500

US Classification:

283 83

Abstract:

Documents are encoded with at least one thin, transparent coating, normally invisible, but having a readily detectable physical characteristic such as, electrical conductivity, electrical impedance, electrical capacitance, electroluminescence. Each document consists of a substrate on which is applied (1) at least one of the thin coatings, and (2) conventional printing, preferably intaglio. The thin coating may be applied before or after the printing. The coating includes particles driven into the surface to a substantial depth. The uncoated substrate is free of the detectable physical characteristic. The coating is confined to a limited area of the substrate surface and itself constitutes a code or is laid down in a pattern for identification. A second coating can be applied so that all areas of the surface have the same appearance to mask visual detection of the first coating. The first coating can be of such a nature as to defeat electrostatic copying, particular, color copying, by effecting a discernible difference between the original and the copy.