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Eradicable inks

  • US 6,221,432 B1
  • Filed: 04/28/1999
  • Issued: 04/24/2001
  • Est. Priority Date: 03/25/1997
  • Status: Expired due to Term
First Claim
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1. A method of changing the color of an ink mark, comprisingapplying an ink comprising an essentially non-aqueous solvent and a triarylmethane dye including a hydrophobic organic counterion dissolved in said solvent that changes color if contacted with a chemical agent to a substrate to provide an ink mark, and applying said chemical agent to said ink mark to cause said triarylmethane dye to change color.

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