Patent GB-1235758-A (GB)
Title: Improvements in or relating to an electrophotographic process and apparatus therefor
IPC: G03G15/18
Filed: 1968-10-21
Abstract: 1,235,758. Electro-photographic processes. KONISHIROKU PHOTO INDUSTRY CO. Ltd. Oct. 21, 1968 [Oct. 25, 1967; June 26, 1968; July 3, 1968; July 24, 1968], No.49789/68. Heading G2H. An electro-photographic plate 1 has an conductive substrate 2, a radiation sensitive layer 3 evaporated or coated on the substrate 2, and an insulating layer 4 having a mesh pattern with spaces for the migration of electrostatic charges between layers as shown in Fig. 3 or in the form of a half tone, or cross line screen pattern. The thickness of the insulating layer is within the range of 0À5 to 100 microns preferably from 5 to 20 microns. The layer may be formed by applying a photomersiable material to the layer 3 and after drying is exposed to U.V. through a mask of the desired pattern, the non-exposed parts are removed by a developer comprising trichloroethylene. Alternatively, the pattern may be formed electrophotographically. Suitable materials for insulating layer are polyethylene, polystyrene, polyester, polyaminide, Teflon (T.M.) vinyl chloride, vinyl acetate, phenol resin and co-polymers thereof. If desired an inter layer may be provided between the radiation sensitive layer and insulating layer. The insulating mesh layer may be formed on a final record member Figs. 9a-9c (not shown) or on an intermediate record layer Figs. 14a to 14d (not shown) in a similar manner to the formation on a radiation sensitive member. Alternatively, the mesh layer may be formed by printing using a transparent resin solution or by using a thermoplastic resin pressed against a heated matrix on a metal roller having the desired pattern. In use, a record member 5, Fig. 4, having an insulating layer 6 and a conductive base 7 is positioned on a counter-electrode 8 in contact with mesh layer 4, pressure of the order of 0À1 to 1 kg/cm<SP>2</SP> being appliedbetweenthe substrate 2 and electrode 8. Electrodes 2<SP>1</SP> and 8 are connected to a D.C. source 9 of the order of -1120 volts. The assembly is imagewise exposed to radiation 12, such that free charge carriers, electrons or positive holes, move to the surface of layer 3 under the influence of the applied field and to the layer 6. Switch 10 is opened and switch 11 closed and the member 5 is separated to permit development and fixing of the latent image on the layer 6. In another embodiment, Fig. 5 (not shown) the layer 3 is exposed through a transparent record member and electrode. The plate 1 Fig. 6C (not shown) previously formed with an electrostatic latent image in known manner is placed in contact with a record member 5 and a roller electrode 8 is moved from left to right while applying positive potential to substrate 2. The latent image is thus transferred from the plate 1 to the record member 5. A copying machine, Fig. 8, has a radiation sensitive member 25 reciprocated in the direction of the arrows past a slit in a shield 24 to expose the member to a transparent orignal 21. A continuous record web 26 is moved past a conductive rubber roller electrode 27 to the right with the member 25 to receive a latent image. The roller electrode 27 is carried by a movable support 30 which is raised to cause the roller to urge the member 26 into contact with a mesh layer on the member 25. Copying machines using an intermediate record layer, Figs. 14a to 14d (not shown) are described with reference to Figs. 17 to 21 (not shown).