Patent ID: 6083663
Filing Date: 2000-07-04
Classification: B41C

Abstract:
A method for making lithographic printing plates including the following steps:a) preparing a heat mode imaging element having on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution, a compound capable of converting light to heat 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 an organic quaternary ammonium salt;b) exposing imagewise said heat mode imaging element to actinic light;c) developing said imagewise exposed heat mode 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;wherein said organic quaternary ammonium salt is a low molecular compound containing at least a C.sub.6 carbon chain.