Method for making a lithographic printing plate wherein an imaging element is used that comprises a thermosensitive mask

摘要

According to the present invention there is provided a method for making a lithographic printing plate comprising the steps of: providing an imaging element comprising on a support having a hydrophilic surface a photosensitive layer and a thermosensitive layer, said thermosensitive layer being opaque to light for which said photosensitive layer has spectral sensitivity and said thermosensitive layer comprising an infrared pigment dispersed in a binder; mounting said imaging element on a drum; image-wise exposing said imaging element by means of an infrared laser in an internal or external drum configuration thereby ablating said thermosensitive layer and rendering it image-wise transparent; overall exposing said imaging element with light to which said photosensitive layer has spectral sensitivity; developing said imaging element to leave an ink accepting image of said photosensitive layer on said support.