Reversibly photochromic printing inks
US5630869A · kind A · utility
30Cited by
6References
2Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 12, 1988 |
| Grant date | May 20, 1997 |
| Priority date | — |
| Expiry date | Jan 12, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/685
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Photochromic printing inks are disclosed which are in particular used for the printing of security documents. Prints are normally nearly colorless and become colored when energy irradiated, such as by ultraviolet light. This photocoloration is reversible. The printing inks contain photochromic compounds which are protected against other ink components. Methods are described to prepare the inks, to print security documents, and to detect counterfeiting.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.