Improvements in or relating to xerographic transfer platen

摘要

1,025,199. Electrophotographic processes. RANK-XEROX Ltd. Jan. 14,1963 [Jan.12, 1962], No. 1524/63. Heading G2H. In a charge transfer process, charge receptive half-tone dots are formed over the surface of the charge receiving sheet 14, in proximity to the tips of elongated conductors 16, by contacting the other ends of the conductors with conductive roller 17 which is connected to a voltage source 51. A continuous tone electrostatic latent image, produced by conventional xerographic methods on photo-conductive layer 13, is accordingly transferred as a half-tone image to sheet 14, developed by cascade at 46 and the developed image transferred under corona discharge at 47. A conductive wiper means at 48 prepares sheet 14 for re-use. Suitable dielectric materials for sheet 14 include cellulose acetate, polystyrene, polytetrafluoroethylene and polyethylene terephthalate. Conductors 16 may be fine wires or ferromagnetic, ferrous or ferrite particles. The latter may be incorporated in a molten layer of dielectric material which is allowed to set under the influence of a transverse particle orienting magnetic field. One side of the layer may be abraded to improve the electrical contact with roller 17 or an alternative contact means. In another form, a sheet of dielectric is pierced with many fine holes, by means of a spark discharge, the holes filled with electrolyte and a film of dielectric applied to one side of the sheet. Reference is made to the use of an A.C. or D.C. corona discharge device in place of conductive roller 17.