Patent ID: 6739260
Filing Date: 2004-05-25
Classification: B41C

Abstract:
A method for the preparation of a negative working lithographic printing plate, said method comprising the following steps, in order,(1) providing a lithographic printing plate precursor comprising a lithographic support and an image forming layer containing a polymeric binder soluble in an aqueous alkaline developer, (2) dispensing image-wise by means of ink jet printing droplets of a fluid onto the surface of said lithographic printing plate precursor, characterized in that said fluid comprises in a solvent carrier a dissolution inhibitor compound capable of reducing the solubility in said aqueous alkaline developer of said polymeric binder, (3) drying the imaged lithographic printing plate precursor to at least partially remove the solvent carrier of the fluid, (4) treating the dried imaged lithographic printing plate precursor with an aqueous alkaline developer thereby removing the non-imaged areas wherein said dissolution inhibitor compound is selected from a group consisting of a compound having a keto group, a N-quaternized triarylmethane dye, a tetraalkly ammonium compound and a N-quaternized N-containing heterocyclic compound.