Printing member for electrostatic photocopying

Claim 1

A printing drum for electrostatic photocopying machine comprising: a conductive substrate; a non-single-crystal p-type semiconductor layer formed on said conductive substrate; a non-single-crystal intrinsic semiconductor layer formed on said p-type semiconductor layer in order to induce a built-in electric field across the interface therebetween; and an insulating layer formed on said intrinsic layer with an external surface to permit the passage of charge photo-generated in said intrinsic layer so that charge on the external surface can be neutralized; where the band gaps of the p-type layer and the intrinsic layer are equal or the band gap of the p-type layer is less than the band gap of the i-type layer which in turn is substantially less than the band gap of the insulating layer; where said p-type layer, said intrinsic layer, and said insulating layer are selected from the group consisting of silicon, silicon with nitrogen, silicon with carbon and silicon with oxygen either in stoichiometric or non-stoichiometric amounts.