Colour laser marking methods of security document precursors
US8786651B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 2011 |
| Grant date | Jul 22, 2014 |
| Priority date | — |
| Expiry date | Nov 28, 2031 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41M2205/38
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A method of color laser marking a security document precursor including, in order, at least: a) a polymeric foil; b) at least one colorless color forming layer for generating a color different from black containing at least an infrared absorber, a color forming compound and a polymeric binder; and c) either a lasermarkable polymeric support or a lasermarkable layer for generating a black color; comprising the steps of: (1) laser marking a color different from black in the colorless color forming layer with an infrared laser used in continuous wave mode; and (2) laser marking a black color by carbonization in the lasermarkable polymeric support or the lasermarkable layer with the same infrared laser used in a pulsed mode; and wherein at least one of the polymeric foil and the lasermarkable polymeric support is transparent for the infrared light of the infrared laser.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.