The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 02, 1996
Filed:
Oct. 04, 1994
Richard E Miller, Nazareth, PA (US);
Charlene Couch, Richmond, VA (US);
Binney & Smith Inc., Easton, PA (US);
Abstract
A coloring system is provided in which an undercolor composition is applied to a substrate to thereby leave a colorless mark. The undercolor composition is then written over with an overcolor composition, thereby causing the undercolor mark to become colored. The overcolor composition may itself contain a colorant. In one embodiment, the color-changing effects are accomplished by employing a dye that is colorless in the presence of high pH and/or a reducing agent, but that becomes colored as the pH is lowered, as the undercolor colorant. In a second embodiment, the color-changing effects are accomplished by employing a dye that is colorless at low pH, but that becomes colored as the pH is raised, as the undercolor colorant.