GB1028018A - Improvements in read-out and transmission of electrostatic information presentations - Google Patents

Abstract

1,028,018. Facsinicle communication systems. RANK XEROX Ltd. Nov. 11, 1963 [Nov. 19, 1962], No. 44368/63. Heading H4F. [Also in Division H1] Information presented in the form of an electrostatic charge pattern on a dielectric member 18 is read out by means of a cathoderay tube N in which the beam 16 is scanned over an array 12 of conductive pins, which pass through the tube wall, to induce a current varying in accordance with the information in the circuit of a backing electrode 20, a corresponding signal resulting therefrom in a resistor 22 being applied through an amplifier 23 to the amplifier 66 of reproducing apparatus where the signal modulates the grid of similar cathode-ray tube 41 to cause the information to be recorded in an identical pattern on a second dielectric member 48. The information may be impressed on member 18 by known means, e.g. an alpha-numeric electrostatic printer, and the recorded information on member 48 may be developed and rendered visible by known means. As illustrated, cathode-ray tubes 11 and 41 are each provided with a line array of pins and the beam is scanned in one direction only along the array. Members 18 and 48 are in the form of webs and are traversed uniformly past and closely adjacent the ends of the pins. According to another arrangement (not illustrated) a two-dimensional array of pins may be used with the beams subject to scanning in two directions. Scanning generators 33, 63, synchronizing pulse generators 31 and synchronising pulse separators 34, 64 are arranged in association with both the read out and recording apparatus, and switches 21, 51; 32, 62; 35, 65 are provided so that the functions may be reversed to permit the system to operate with two-way working. In a first modification of the read-out apparatus, Fig. 4 (not shown), member 18 is in the form of a conductive drum bearing a photo-conductive layer. As the drum rotates, in a first position it is subject to a precharge, in a second position it is exposed to an optical image and in a third position the image is read out by a cathode-ray tube arranged as in Fig. 1. In a second modification, Fig. 5 (not shown), the read-out cathode-ray tube is constructed to operate in a manner similar to an orthicon camera tube in which the signal is produced in response to electrons returned within the tube from the pin electrodes.