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Method for distinguishing printed originals from copies

  • US 5,064,221 A
  • Filed: 03/02/1990
  • Issued: 11/12/1991
  • Est. Priority Date: 03/02/1989
  • Status: Expired due to Term
First Claim
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1. Method for making printed originals distinguishable from copies, which comprises:

  • (a) using an ink ribbon as a printing medium for printing originals;

    (b) adding a substance to the ink ribbon in the form of a marking;

    (c) printing an original with the marked ink ribbon for producing invisible distinguishable markings in the printed original being recognizable solely by means of special scanners.

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