JP2006023752A5 - - Google Patents

Claims (5)

(I) a heat-sensitive negative working printing plate precursor having a support having a hydrophilic surface or provided with a hydrophilic layer and a coating provided thereon, wherein the coating is a hydrophobic thermoplastic polymer Comprising an image recording layer comprising particles and a hydrophilic binder, wherein the hydrophobic thermoplastic polymer particles have an average particle size in the range of 45 nm to 63 nm and the hydrophobic heat in the image recording layer Providing a printing plate precursor in which the amount of plastic polymer particles is at least 70% by weight with respect to the image recording layer;
(Ii) exposing the coating to heat or infrared light, thereby inducing coalescence of thermoplastic polymer particles in the exposed areas of the coating;
(Iii) developing the precursor by applying an alkaline aqueous solution having a pH > 11 and comprising a phosphate buffer or a silicate buffer, thereby removing the unexposed areas of the coating from the support A method for producing a lithographic printing plate comprising the step of:   The method for producing a lithographic printing plate according to claim 1, wherein the hydrophobic thermoplastic polymer particles have an average particle diameter in the range of 45 nm to 55 nm.   3. A method for preparing a lithographic printing plate according to claim 1, wherein the amount of hydrophobic thermoplastic polymer particles in the image recording layer is less than or equal to 85% by weight with respect to the image recording layer. The method for preparing a lithographic printing plate according to claim 1, wherein the hydrophilic binder is soluble in an aqueous developer having a pH > 10.   The method of making a lithographic printing plate according to any one of claims 1 to 2, further comprising one or more compounds that provide a visible image after the coating is image-wise exposed but before development.