GB926723A - Electrostatic recording - Google Patents

Abstract

926,723. High-speed printers. TELETYPE CORPORATION. Dec. 7, 1961 [Dec. 27, 1960], No. 43807/61. Class 100 (4). Pulse operation; type-wheel machines.-In an electrostatic computor output printer in Fig. 2, alpha-numerical information is recorded by the use of digital computor techniques, on a dielectric web 25, having a resistive layer 70 in contact with a character drum 42 rotating at a constant speed and an overlying insulating layer 71 spaced from a transversely disposed array of backing electrodes 55, one for each character ring 52 of the character drum. The sequential selection of the proper character ring 52 and associated character type 53, one for each revolution of the drum, is effected by a magnetic mark 51 on the drum emitting a pulse on passing over a magnetic head 58, which transmits the pulse to a revolution counter 59 so as to energize one of the lines of a selection matrix 60, the line being fully activated to transmit a pulse through a voltage amplifier 68 when a gate 61 is rendered operative, as the selected character is opposite the electrode 55, to form a latent electrostatic pattern on the web. The gate operates when magnetic marks 62, one for each character, are sensed by a magnetic head 64, transmitted to a character counter 65, compared in a comparator 66 with the character inserted in a character register 67, and when on the detection of identity an output signal is emitted by the comparator 66. To print a full line the character drum must complete as many revolutions as there are columns to be printed. To compensate for skewing of the printed line the drum may be placed at an angle relative to the paper or the rings may be displaced relative to each other. In another embodiment (not shown), line-byline printing may be employed, wherein the electrodes are provided with a line storage memory device. Web-feeding; inking.-The web 25 in Fig. 1, having a resistive layer 70 of paper overlying an insulating layer 71 of a synthetic plastic material is fed from a supply roll 24 past a controlled tensioning device 26, 27 and advanced through a recording stage 20 in which the printing takes place. The latent images are rendered visible as the web passes the development mechanism 28, by depositing thereon an ink mist or electroscopic pigmented resin powder and the visible images are subsequently heated to dry the ink or fuse the resin in a fuser 30. Instead of fusing the resin images can be transferred to paper offset webs, or if of a small size produced by xerographic or photographic enlargement. Type-wheels and type surfaces.-The cylindrical drum 42, which may be of aluminium, has a plurality of type wheels 52, having mounted on their periphery raised steel alphanumerical characters 53. The spaces between the characters may be filled with a synthetic plastic material to present a smooth surface.