Patent ID: 6749984
Filing Date: 2004-06-15
Classification: B41C

Abstract:
A positive-type planographic printing plate precursor comprising:a photosensitive layer as a top layer and obtained by coating and drying on a support a photosensitive layer coating solution formed of a photosensitive composition, which contains a cyanine dye represented in the following general formula (I) and a polymer insoluble in water and soluble in an aqueous alkali solution, dissolved or dispersed in a solvent system, which includes a solvent having a boiling point lower than 200Â° C., wherein 80% by weight or more of the solvent consists of a solvent having a boiling point lower than 100Â°; wherein a solubility in an aqueous alkali solution of the photosensitive layer is increased by an infrared laser exposure: â€ƒwherein, each of Y1 and Y2 represents a dialkylmethylene group or a sulfur atom; each of R3 and R4 represents an alkyl group, alkenyl group, alkynyl group or phenyl group which may be substituted; L2 represents a trimethine group, pentamethine group or heptamethine group which may be substituted, and two substituents of the pentamethine group or the heptamethine group may be combined with each other to form a cycloalkene ring having 5 to 7 carbon atoms; each of R5 through R8 represents a hydrogen atom or an alkyl group, alkenyl group, alkoxy group, cycloalkyl group or aryl group which may be substituted, and R5 and R6, and R7 and R8 may be combined with each other to form a ring structure; and Xâˆ’ represents an anion wherein of the residual solvent contained in the photosensitive layer 50% by weight or more of the solvent consists of solvent having a boiling point lower than 100Â°.