A 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 comprising 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 IR-sensitive and unpenetrable for 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 at least one blockcopolymer in an amount between 0.5 and 500 mg/m<2>.