Patent ID: 8786651
Filing Date: 2014-07-22
Classification: B41M

Abstract:
1. A method of colour laser marking a security document precursor including, in order, at least: a) a transparent polymeric foil; b) at least one colourless colour forming layer for generating a colour different from black containing at least an infrared absorber, a colour forming compound and a polymeric binder; and c) either a lasermarkable polymeric support or a lasermarkable layer for generating a black colour; comprising the steps of: (1) laser marking a colour different from black in the colourless colour forming layer with an infrared laser used in continuous wave mode; and (2) laser marking a black colour 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 transparent polymeric foil and the lasermarkable polymeric support is transparent for the infrared light of the infrared laser.