PURPOSE: To make directly a printing plate through the electrophotographic process and to enhance printing resistance by forming a layer composed essentially of a specified azo pigment and an alkali-soluble resin on a conductive substrate.
CONSTITUTION: A conductive substrate is coated with a layer composed essentially of an alkali-soluble resin and an azo pigment represented by the formula shown here in which A is a coupler residue. As the coupler of the formula, compds. having a phenolic OH group, such as phenols and naphthols, and an aromatic compds. having an amino group, etc. are used. As said alkali-soluble resin, a resin solubilizable in an aq. or alcoholic solvent by addition of alkali, and, e.g. a styrene-maleic anhydride copolymer, a styrene-methacrylic acid- methacrylate copolymer, etc., are used, and for this resin, film forming property, electric characteristics, strength of adhesion to a substrate, and especially solubility characteristics, etc. are important. The printing plate of such a constitution is good in sensitivity and it can be directly manufactured by using various kinds of light sources, such as laser, and the obtained printing plate has high printing resistance.
OOTA MASABUMI