Printing plates comprising ink receptive azo dye surfaces

Claim 1

A PROCESS OF MAKING A PRINTING PLATE SUITABLE FOR USE IN PHOTOMECHANICAL REPRODUCTION COMPRISING COATING A BASE WITH A SOLUTION COMPRISING A RESINOUS MIXTURE OF A CELLULOSE ESTER AND A COPOLYMER OF POLYVINYL ALKYL ETHER AND MALEIC ANHYDRIDE, DISSOLVED IN A SOLVENT MEDIUM FOR SAID MIXTURE, DRYING SAID COATING TO FORM A LAYER OF SAID RESINOUS MIXTURE ON SAID COATING TO FORM A SAID LAYER WITH A SOLUTION COMPRISING A MIXTURE OF A LIGHT-SENSITIVE MONOFUNCTIONAL QUINONE DIAZIDE AND AN AZO COUPLING COMPOUND CONSISTING OF AT LEAST TWO PHLOROGLUCINOL NUCLEI LINKED TOGETHER THROUGH OXYGEN ATOMS JOINED TO AN ALKYLENE GROUP, DRYING SAID COATING, EXPOSING TO RADIATION THE THUS COATED PAPER BENEATH A PATTERN WHEREBY THE MONOFUNCTIONAL QUINONE DIAZIDE UNDER THE NON-IMAGE PORTIONS OF THE ORIGINAL IS BLEACHED OUT, DEVELOPING THE EXPOSED PAPER WITH MOIST AMMONIA FUMES, WHEREBY THE NON-IMAGE PORTIONS OF THE COATED PAPER ARE RENDERED WATER RECEPTIVE AND A POSITIVE DYE IMAGE IS PRODUCED IN THE NON-EXPOSED AREAS AND TREATING THE DEVELOPED PAPER WITH A SOLUTION CAPABLE OF REMOVING THE PHOTODECOMPOSITION PRODUCTS THEREFROM.