| 摘要 |
1,201,497. Electro-photographic process. RANK XEROX Ltd. Sept.28, 1967 [Sept.29, 1966], No.44120/67. Heading G2H. [Also in Division H1] In a pin matrix which may be incorporated in a c.r.t. the pins are connected to a common point through a common field-effect semi-conductor layer and there is provided means to impose an image-configurated electric field through the layer whereby the conductivity of the layer is varied in accordance with the field and whereby the impedance to the point of the pins is varied in accordance with the field. An electrostatic charge pattern 15 is built up on the surface of a layer 13 of insulator e.g. SiO or MgF 2 or photoconductive insulator e.g. Se together with an insulating layer. A conductive grid 11 of vapour deposited Cu or electro-deposited In lies in contact with layer 13 and has a semi-conductor layer 9 on its other side. Layer 9 may be CdS, CdSe, As 2 S 3 or ZnO and is built up on the glass pin matrix 5 by sputtering or evaporation. The pins lie in contact with a paper sheet 19 on a conductive support 20. In a modification Fig.3 (not shown) the grid is formed directly on the glass layer 5 and the semi-conductor material e.g. ZO, PbO or CdO deposited over the grid and the layer. A composition comprising ZnO, copoly styrenebutadlene, chlorinated paraffin and a mixture of dyes may be used alternatively Zn may be sputtered or evaporated and subsequently oxidized. A photo-conductive insulator is used for layer 13 a charge pattern may be established on its surface using an optical image and a conventional xerographic technique. In operation, the paper sheet 19 may be electrostatically charged, positioned on the support 20 adjacent the pins 7 and selectively discharged by the pins to the grid 11 according to the charge pattern on the surface 13. The impedance between a particular pin and the grid is varied by the semi-conductor layer 9 whose impedance is controlled by the electric field imposed on it by the charge pattern on layer 13. Alternatively sheet 19 is positioned adjacent pins 7 without prior charging and a D.C. potential applied across the sheet, thus giving a negative charge pattern. The resulting charge pattern on sheet 19 may be developed with electroscopic particles. In an alternative embodiment Fig.4 (not shown) an image pattern is formed electrostatically using a device similar to that shown in Fig.2 but wherein the pins 7 do not protrude beyond the layer 5, the sheet 19 eliminated and the support 20 replaced by a Nesa glass electrode (39, 41) spaced from layer 5 to provide a cell for electrolyte (35). The electrolytic image may be made on either the glass electrode or the layer 5. Alternatively a thin conducting, insulating or semi-conducting sheet may be placed either on the electrode or the layer and the image formed thereon. |
