HEAT MODE SENSITIVE IMAGING ELEMENT FOR MAKING POSITIVE WORKING PRINTING PLATES

摘要

According to the present invention there is provided a heat mode imaging element for making a lithographic printing plate having on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution but not in water and less than 5% by weight versus the polymer, soluble in the aqueous alkaline solution of a hydrophilic polymer and a top layer on the same side of the lithographic base as the first layer which top layer is IR-sensitive and unpenetrable for or insoluble in an alkaline developer wherein said first layer and said top layer may be one and the same layer; characterized in that said top layer contains a compound selected from the group consisting of a polymer in an amount from 30 mg to 500 mg/m2, a triaryl methane dye and a phthalocyanine dye.