ALKALI DEVELOPING SOLUTION USED FOR DEVELOPING POSITIVE PHOTOSENSITIVE PLANOGRAPHIC PRINTING PLATE MATERIAL AND PLATEMAKING METHOD OF PLANOGRAPHIC PRINTING PLATE

摘要

PROBLEM TO BE SOLVED: To reduce influences on developing performances, caused by precipitation of silicates due to vaporization of the water content from a developing solution and by generation of products resulting from the precipitation, and further, influences on the quality of a plate material, caused by transfer of the products onto a plate material surface.;SOLUTION: An alkali developing solution to be used for developing a positive photosensitive planographic printing plate material is provided, containing at least an alkali metal salt (a) of silicic acid, a polyhydric alcohol (b) having 2 to 5 carbon atoms, a chelating agent (c), and water. The amount of the alkali metal salt (a) of silicic acid is 6.25 to 7.00 parts by weight with respect to 100 parts by weight of the alkali developing solution; the amount of the polyhydric alcohol (b) having 2 to 5 carbon atoms is 0.2 to 10 parts by weight with respect to 100 parts by weight of the alkali developing solution; and the amount of the chelating agent (c) is 0.005 to 0.5 part by weight with respect to 100 parts by weight of the alkali developing solution.;COPYRIGHT: (C)2008,JPO&INPIT