Browse Prior Art Database

Original Publication Date: 1981-Dec-31
Included in the Prior Art Database: 2004-Apr-02

Publishing Venue

Xerox Disclosure Journal


In an electrophotographic printing machine, highly conductive, single component developer material is frequently used to develop a latent image recorded on a photoconductive surface. However, transfer of conductive toner particles from the photoconductive surface to the copy sheet is not necessarily of high quality. Transfer efficiency and image resolution may be improved by utilizing a trans-parent photoconductive member and illuminating the photoconductive member during transfer through the rear. The copy sheet is supported by a conductive member. Alternatively, the insulating surface may be overcoated with a thin layer of material having a field degsndent resistivity. The resistivity at low develop-ment fields is greater than 10 lahm-cm with the resistivity of high fields, during transfer, being greater than 10 ohm-cm. As shown in the drawing, development occurs at voltages where the resistivity of the developer material/f ield dependent resistivity layer is ohmic and transfer occurs in the non-ohmic regions of the curve at a field where the developer material/paper resistivity is higher than the developer material/field dependent resistivity layer resistivity. Suitable coatings include insulating plastic with a conductive pigment dispersion, such as magnetite and carbon black.