Latent imaging and developer system
US4631203A · kind A · utility
Inventors
Key dates
| Filing date | Apr 8, 1985 |
| Grant date | Dec 23, 1986 |
| Priority date | — |
| Expiry date | Apr 8, 2005 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41M5/132
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
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 CuSO.sub.4, 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 obtained upon development. The system of the invention can be used in a variety of contexts, such as in self-testing materials or novelty items.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.