Ink and method for the development of concealed images
CA 1330705 C · Owner: Kulisz, Michael · Inventors: Kulisz, Michael
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a system for developing latent images on alkali-based or acid-based paper stock which had been marked with a water-soluble oxidizing agent to form a concealed image. In the system a, marking composition is applied to said paper stock which comprises, (a) A water-soluble iodide (b) Acetic acid, (c) A water-soluble reducing agent and, (d) Water. Preferably, the reducing agent is ascorbic acid and preferably the marking composition also comprises a water-soluble dye.
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 July 19, 1994. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 19, 2011.
- 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.