Desensitizing treatment liquid for lithographic printing

摘要

A desensitizing treatment liquid for offset printing plates, which contains a compound represented by formula (I) wherein phi represents -PO₃H₂, -OPO₃H₂, or the salt thereof and R₁ represents an organic residue which may have a substituent. The desensitizing treatment liquid gives no problems to environmental pollution, is stable to the long-period storage and the continuous use, can shorten the etching treatment time, and is excellent in the desensitizing treatment ability as well as can provide an offset printing plate having a good reproducibility of highly minute images of a middle tone, screen tint, etc., and capable of printing without forming scumming at the non-image area.