Latent imaging and developer system
CA 1283798 C · Owner: Walker, Haywood A. Jr. · Inventors: Walker, Haywood A. Jr.; Schaefer, Rolf
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A sharp imaging non-smearing system for latent, imaging and subsequent visual development of printed text or the like is provided which can be used on a variety of substrates (e.g. paper, metal, cloth, synthetic resins) and is extremely stable and easy to use. The system involves first imaging a substrate with an invisible ink containing a dissociable transition metal salt such as CuSO4, with subsequent application of a liquid developer containing a solubilized color precursor such as thiooxalic amide which complexes with dissociated transition metal ion to give a sharp, virtually instantaneously developing, long lasting color. Depending upon the metal salt selected different colors, can be …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted May 7, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 7, 2008.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.