Patent ID: 7416836

Claim:
A method for making a lithographic printing plate comprising the steps of: light-exposing to infrared radiation, a heat-sensitive presensitized plate of a positive-working mode for use in making a lithographic printing plate, said presensitized plate comprising a substrate and an image recording layer which is formed thereon and which comprises a novolak resin containing xylenol selected from the group consisting of 3,5-xylenol, 2,3-xylenol, 2,5-xylenol and 3,4-xylenol, as a monomer component, and an infrared absorbing dye; and developing the light-exposed plate with an alkaline developing solution comprising a polyoxyalkylene adduct of alkylene diamine having a molecular weight of not more than 2000 and a polyoxyalkylene adduct of alkylene diamine having a molecular weight of not less than 3000, the amount of the polyoxyalkylene adduct of alkylene diamine having a molecular weight of not more than 2000 being 5 to 200 times the amount of the polyoxyalkylene adduct of alkylene diamine having a molecular weight of not less than 3000, wherein the total amount of polyoxyalkylene adducts of alkylene diamine is from 0.001 to 10% by weight, a polyoxyalkylene compound having an acid radical in an amount of from 0.001 to 20% by weight, and an anionic surfactant in an amount of from 0.001 to 20% by weight, said alkaline developing solution having a pH of from 12.5 to 14.0.