Patent GB-733484-A (GB)
Title: Improvements in and relating to methods of and apparatus for recording and portraying information
IPC: G03G19/00
Filed: 1952-04-28
Abstract: 733,484. Digital electric calculating-apparatus; recording-apparatus. BRITISH THOMSON-HOUSTON CO., Ltd. April 28, 1952 [April 27, 1951], No. 10651/52. Classes 106 (1) and 106 (4). [Also in Groups XVI and XL (b)] Apparatus for reproducing or recording information comprises magnetizing means, for applying to a carrier of ferro-magnetic material, such as soft iron, nickel or cobalt, flux densities having values corresponding to the character of the information so as to produce a magnetic image of the information and means for bringing the magnetized carrier into contact with a developing material which is attached by the carrier in accordance with the magnetization of its various portions so as to produce on the surface of the carrier a reproduction of the said information by the disposition of the developing material. In one arrangement, Fig. 1, the end 15 of a magnetic stylus 14 is oscillated in contact with or close to, the surface of a magnetic drum 11 which rotates in a container 19 of magnetic material 18 and subsequently engages under control of a roller 22, a printing sheet 23 fed by rollers 20, 21. A magnet 24 demagnetizes the drum 11 from which adhering material is removed by brushes 25. In a modification, Fig. 3 (not shown), the single stylus is replaced by a longitudinal series of stylus members associated with the drum and selectively actuated in accordance with the amplitude of an incoming signal so that a trace of a received wave form can be reproduced. In a further modification, Fig. 4, a rotatable drum 36 carries a helical rib 35 of magnetic material co-operating with a longitudinal electrode 39 actuated by an electromagnet 38 controlled from circuits 43, 45 which may be such as to produce a single pulse at some predetermined instant during each revolution of the drum 36. The magnetized sheet 11a is fed over rollers 33, 33a, 33b, and is sprayed with magnetic material 18 from a container 19 by a band 47 vibrated by a star-shaped cam member 48. At the printing position the second sheet 23 is pressed against the sheet 11a by a roller 22a which is radially magnetized. The roller 33a is also radially magnetized, the direction of magnetization provided by the rollers 22a, 33a being such that it is opposite to that produced in the sheet 11a. In a modification, Fig. 7, adapted for use with digital computers, a rapidly rotated drum 51 carries rings of radially movable magnetic members 52 whose ends are shaped corresponding to numerals and which are associated with a relatively slow-moving magnetic drum 11. An electromagnet 54 is associated with each ring and is selectively operated by a pulsing device 102 controlled by a number storing and translating unit 101 such that pulses produced from a member 104 on magnets 103 spaced equally with the members 52 step the translating unit towards its zero position in which it produces an impulse to operate the associated magnet 54, the number of pulses applied to the translating unit to reach the zero position determining which of the members 52 is to be operated by the magnet 54. The members 101, 102 are also controlled by a synchronizing or zero position pulse generated.,by a member 106 associated with a magnet 105. The magnetic material 18 which is in a container with a V-shaped opening 57, is blown against the drum 11 by gas admitted at an adjustable pressure through tubes 58 and the drum is demagnetized by a magnet 24. In a modification of Fig. 7, Fig. 9 (not shown), the magnetic drum 11 is replaced by an endless magnetic sheet passing over driving and guiding rollers, and the operating electromagnets are located on the side of the magnetic sheet opposite to the character plugs on the rotating drum. In this modification, the magnetic sheet passes through a container containing magnetic material in a solution of printing ink prior to its passage to the printing position. Specifications 684,587, (Group XXXVIII], and 686,009, [Group XL (b)], are referred to.