Patent ID: 8117964

Claim:
A printing process wherein a printing plate bearing wet ink at its surface within a predetermined area transfers said wet ink onto a sheet or web, thereby imprinting a corresponding area of said sheet or web, including a step consisting of directing a laser beam of a laser marking device onto said predetermined area of the wet inked surface of said printing plate to evaporate wet ink from the wet inked surface just before said area of said printing plate contacts said sheet or web, wherein the fluidity of said wet ink, the speed of the laser irradiation and the timespan between the laser irradiation and the entry into contact of said area of said printing plate with said sheet or web are selected and set so that said wet ink is completely evaporated along a path defining an identity mark, said identity mark existing in form of merely unprinted paths within a printed area, and so that said wet ink contained in the areas of said printing plate surrounding said path does not spontaneously flow into said path.