Patent ID: 6946239

Claim:
A method of developing a photosensitive planographic printing plate which has been exposed to an infrared light beam with an alkaline developer containing at least one saccharide selected from non-reducing sugars and at least one base, the photosensitive planographic printing plate including a support having a surface which has been subjected to hydrophilic treatment having disposed thereon a recording layer formed by applying to the support a positive photosensitive composition for an infrared laser, the positive photosensitive composition including: (A) at least one alkali aqueous solution-soluble polymer compound having at least one functional group selected from (a-1) a phenolic hydroxyl group, (a-2) a sulfoneamide group, and (a-3) an active imide group; either (B) a compound that lowers the solubility of the at least one alkali aqueous solution-soluble polymer compound because of its compatibility with the alkali aqueous solution-soluble polymer compound in an alkali aqueous solution, with the solubility-decreasing action being reduced by heat; and (C) a compound that generates heat by absorbing light, provided that (B) and (C) are different; or (BC) a compound that (i) lowers the solubility of the at least one alkali aqueous solution-soluble polymer compound because of its compatibility with the alkali aqueous solution-soluble polymer compound in an alkali aqueous solution, with the solubility-decreasing action being reduced by heat, and (ii) generates heat by absorbing light; and (D) a cyclic acid anhydride, wherein the photosensitive planographic printing plate is immersed in the developer while being conveyed, and development is accelerated by brushing the immersed photosensitive planographic printing plate with a brush member produced by winding, around a peripheral surface of an axially rotating roller, a brushing band composed of a sheet-like substrate containing a hairy material woven therein; and wherein the alkaline developer further contains at least one compound selected from the group consisting of compounds represented by formula (IA) or formula (IIA) and salts thereof: wherein R 1 and R 2 each represent a hydrocarbon group having 4 to 30 carbon atoms, and m, n and p each represent an integer of 1 to 10.