TREATMENT OF PROCESSING LIQUID FOR PLANOGRAPHIC PRINTING PLATE

摘要

PURPOSE:To provide the method for treating a processing liquid for planographic printing plates which can easily treat the highly alkaline processing liquid in correspondence to a wide range of liquid pH and decreases the burden of the treatment of the waste processing liquid in the treatment of the fatigued alkaline processing liquid to be generated accompanying plate making processing. CONSTITUTION:This method for treating the processing liquid in the plate making processing of the planographic printing plates consists of supplying the alkaline processing liquid to the planographic printing plates on which images are formed, to dissolve non-image parts, then removing the alkaline processing liquid on the printing plates and the dissolved non-image parts. An org. compd. having at least 9 to 11 acid dissociation index (pKa) is added into the liquid contg. at least the alkaline processing liquid fatigued by the processing to regulate the liquid pH to 11.0 to 12.5.