DEVELOPER FOR POSITIVE PHOTOSENSITIVE LITHOGRAPHIC PRINTING PLATE, REPLENISHED DEVELOPER AND METHOD FOR DEVELOPING POSITIVE PHOTOSENSITIVE LITHOGRAPHIC PRINTING PLATE

摘要

PURPOSE: To provide a combination of developer, replenished developer and a photosensitive lithographic printing plate with the developability improved even in repeated development over a long period and without a deposit being generated in a developing bath or printing durability being deteriorated. CONSTITUTION: A positive photosensitive lithographic printing plate formed by providing a photosensitive layer on the substrate obtained by treating an anodized aluminum substrate further with a silicate is developed while adding a replenished developer to developer contg. an alkali metal silicate continuously or intermittently. The (SiO2 )/(M) (where (SiO2 ) is the SiO2 molarity and (M) is the alkali metal molarity) is 0.15-0.50 in the developer and replenished developer contg. the alkali metal silicate and the SiO2 concn. is controlled to 1.0 to 4.0wt.% based on the total weight of the developer plus replenished developer.