Patent ID: 6165689
Filing Date: 2000-12-26
Classification: B41C,G03F

Abstract:
A method for making lithographic printing plates including the following steps:a) preparing a light sensitive imaging element having on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer which top layer is unpenetrable for an alkaline developer containing SiO.sub.2 as silicate and which top layer includes diazonium salt and for at least 20% of its weight one or more non-proteinic hydrophilic film-forming polymers;b) exposing imagewise said light sensitive imaging element to actinic light;c) developing said imagewise exposed light sensitive imaging element with said alkaline developer so that the exposed areas of the top layer and the underlying areas of the first layer are dissolved and the unexposed areas of the first layer remain undissolved.