Patent ID: 9067450
Filing Date: 2015-06-30
Classification: B41M

Abstract:
1. A method of colour laser marking a security document precursor including at least: a polymeric foil; 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 a laser markable polymeric support or a laser markable layer for generating a black colour through carbonization; comprising the steps of: laser marking the colourless colour forming layer with an infrared laser utilized in pulsed mode at a pulse repetition rate of at least 15 kHz to generate a colour different from black; and laser marking the laser markable polymeric support or the laser markable layer with the same infrared laser utilized in a pulsed mode at a pulse repetition rate of at most 5 kHz to generate a black colour.