Patent ID: 8361700

Claim:
A method for preparing a lithographic printing plate, comprising: providing a lithographic printing plate precursor comprising: a support having a surface, a contact angle of water droplet in air on which is 70° or more; and a photosensitive layer, wherein the support has, on a surface of the support, a compound having a functional group X, the functional group X being a functional group capable of forming a chemical bond with a compound having a functional group Y which can interact with the functional group X, when the functional group X is brought into contact with the compound having a functional group Y, to adsorb the compound having a functional group Y on the surface of the support to decrease the contact angle of water droplet in air on the surface of the support to 30° or less; exposing imagewise the lithographic printing plate precursor; and developing the exposed lithographic printing plate precursor with an aqueous solution having pH of from 2 to 10 to form a non-image area, wherein at or after the development, the lithographic printing plate precursor is treated with an aqueous solution containing the compound having a functional group Y, to decrease the contact angle of water droplet in air on the surface of the support in the unexposed area to 30° or less; wherein: the functional group X is a functional group represented by the following formula (0): wherein R 1 to R 3 each independently represents a monovalent group comprising at least one atom selected from the group consisting of hydrogen, carbon, oxygen, nitrogen, sulfur, phosphorus, halogen and silicon or a covalent bond, or appropriate two of R 1 to R 3 may be combined with each other to form a ring, provided that at least one of R 1 to R 3 represents a divalent connecting group for connecting to a skeleton of the compound having the functional group X, which comprises at least one atom selected from the group consisting of hydrogen, carbon, oxygen, nitrogen, sulfur, phosphorus, halogen and silicon; and the functional group Y is a functional group selected from the group consisting of —SO 3 H, —PO(OH)(OM) and —B(OH)(OM) wherein M represents a hydrogen atom, a metal cation, an ammonium group, a phosphonium group, an iodonium group, a sulfonium group, a diazonium group or an azinium group.