Laser printing method and substrate

摘要

A method and substrate for printing information wherein at least one coating is applied to a substrate, the coating having a colorformer leucodye and at least one color activator. The colorformer leucodye and at least one activator react when heated to exhibit a chromic change of at least one of a color change visible in normal light and a fluorescence visible only in ultraviolet light. The at least one coating is heated with at least one laser beam to effect the chromic change at selected points to thereby print information.