. . . "Resins usable as the binder include insulating resins such as acrylic resins, polyallylates, polyesters, polycarbonates, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfones, polyacrylamide, polyamides and chloridized rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinyl anthracene." .