Process for the production of developed electrophotographic images including application of a breakdown potential to discrete small areas of a photoconductor

Claim 1

IN AN ELECTROPHOTOGRAPHIC PROCESS WHICH COMPRISES APPLYING AN ELECTROSTATIC CHARGE TO A CONTINUOUS LAYER OF PHOTOCONDUCTIVE INSULATING MATERIAL PROJECTING A LIGHT IMAGE ONTO THE SAID LAYER WHEREBY A FLOW OF ELECTRICITY TAKES PLACE THROUGH SAID LAYER PRODUCING AN ELECTROSTATIC LATENT IMAGE AT A SURFACE THEREOF, AND DEVELOPING THE SAID IMAGE BY DEPOSITING TONER PARTICLES ON THE SAID SURFACE TO WHICH THE SAID TONER PARTICLES ADHERE IN A DISTRIBUTION VARYING IN DENSITY WITH THE INTENSITY OF THE ELECTROSTATIC IMAGE CHARGE AT THE VARIOUS PARTS OF THE SURFACE, THE IMPROVEMENT WHICH COMPRISES INITIALLY APPLYING THE ELECTROSTATIC CHARGE TO THE LAYER OF PHOTOCONDUCTIVE INSULATING MATERIAL BY SUBJECTING IT TO AN ELECTRIC POTENTIAL BY MEANS OF A CORONA DISCHARGE, WHICH POTENTIAL IS LARGE ENOUGH TO CAUSE THE LAYER TO BREAK DOWN ELECTRICALY AT A MULTIPLICITY OF CLOSELY SPACED DISCRETE LOCATIONS AND TO CHARGE THE SURFACE PORTIONS BETWEEN THE BROKEN DOWN SITES, AND DEPOSITING TONER PARTICLES WHICH ARE ESSENTIALLY UNCHARGED.