Electrophotographic printing original plate and electrophotographic plate making process using the printing original plate

An electrophotographic printing original plate which comprises:

• a. an electroconductive support material, and
• b. an electrophotographic photosensitive layer formed thereon, said electrophotographic photosensitive layer comprising (i) a charge generating layer consisting essentially of an azo pigment serving as a charge generating material and (ii) a charge transport layer consisting essentially of a charge transporting material and an alkali-soluble resin, said azo pigment being selected from the group consisting of the azo pigments having the following formulas (1) through (44):
• ##STR165## wherein A represents a coupler residue selected from the group consisting of the coupler residues having the formulas (A-1) through (A-6):
• ##STR166## wherein R.sup.1 is hydrogen, an alkyl group, an unsubstituted or substituted phenyl group;
• X is an unsubstituted or substituted cyclic hydrocarbon group, or an unsubstituted or substituted heterocyclic group;
• Y is an unsubstituted or substituted cyclic hydrocarbon group, an unsubstituted or substituted heterocyclic group, or ##STR167## (in which R.sup.2 is an unsubstituted or substituted cyclic hydrocarbon group, an unsubstituted or substituted heterocyclic group, an unsubstituted or substituted styryl group;
• R.sup.3 is hydrogen, an alkyl group, an unsubstituted or substituted phenyl group;
• or R.sup.2 and R.sup.3 can form a ring in combination with carbon atoms bonded to R.sup.2 and R.sup.3), ##STR168## wherein R.sup.4 is an unsubstituted or substituted hydrocarbon group, ##STR169## wherein R.sup.4 is an unsubstituted or substituted hydrocarbon group, ##STR170## wherein R.sup.5 is an alkyl group, a carbamoyl group, a carboxyl group or an ester group thereof;
• Ar.sub.1 is an unsubstituted or substituted cyclic hydrocarbon group, ##STR171## wherein R.sup.6 is an unsubstituted or substituted hydrocarbon group and Ar.sub.2 is an unsubstituted or substituted cyclic hydrocarbon group;
• and Ar in the formulas (5), (8) and (9) represents ##STR172##