Desensitizing treatment liquid for lithographic printing

A desensitizing treatment liquid for lithographic printing, which contains at least one kind of a compound represented by formula (II);

• R1—(NZn)m (II)
• wherein Z represents —CH2φ or a hydrogen atom;
• n and m represent integers a combination of which has at least five —CH2φ represents —PO3H2, —OPO3H2, or the salt thereof and R1 represents an organic residue which may have a substituent,
• said compound being capable of chelating with a polyvalent metal ion which is generated from a metal oxide or a metal sulfide existing on the surface of a lithographic printing plate by etching treatment to form a sparingly water-soluble precipitation.

A desensitizing treatment liquid for lithographic printing, which contains at least one kind of a compound represented by formula (IV);

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• wherein R2, R3, R4, and R5 each represents a hydrogen atom, an alkyl group having from 1 to 3 carbon atoms, which may be substituted, or a halogen atom;
• Y represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, which may be substituted, an alkoxy group which may be substituted, a halogen atom, an amino group, a nitro group, a cyano group, a carboxy group, or a hydroxy group;
• and φ represents—PO3H2, —OPO3H2, or the salt thereof,
• said compound being capable of chelating with a polyvalent metal ion which is generated from a metal oxide or a metal sulfide existing on the surface of a lithographic printing plate by etching treatment to form a sparingly water-soluble precipitation.