| abstract |
1338893 Security paper XEROX CORP 1 Dec 1970 [4 Dec 1969] 56962/70 Heading B6A [Also in Division C4] To render a document resistant to copying, it is coated with a fluorescent material which absorbs, and is excited by, visible light. The material is fluorene, rubrene, penylene or fluoroscein in a solid solution of polycarbonate resin. The coating is prepared by dissolving the material and resin in methylene chloride and is applied by painting or aerosol spraying. Selected areas only of the document may be coated and several different coating materials may be used. The material prevents copying in apparatus using light sensitive blanks. |