GB1464468A - Visual and magnetic recording system - Google Patents

Abstract

1464468 Visual and magnetic data recording system J R ANDREAGGI and R J GRAF 8 May 1974 20267/74 Heading G4M A visual and magnetic data recording system has a typewriter 26 producing visual characters on the front surface of a sheet and recording data representing the character on a magnetic backing to the sheet in a fixed positional relationship to the visual character. The typewriter keys are arranged to operate switches 35 coupled to a diode coding matrix which supplies signals on eight lines to a recording circuit. The signals have six bits defining the character, a bit indicating whether upper or lower ease is used and a parity bit. The magnetic character on the rear surface is situated vertically in line with and spaced above the corresponding visual character. The recording head (Fig. 6) carries eight equally spaced wires 53-1 to 53-8 used to record the eight bits of each character, the wires produce magnetic areas in the backing aligned according to the direction of current in the wires (Figs. 2, 3 not shown). The wires do not form a complete single turn on a mandrel 52, are coupled to separate pins 53-1A 53-1B to 53-8A, 53-8B on a connector 59 and carry a high current for a short time. The eight wires are spaced by turns 54 of a continuous wire forming an erase portion of the head and extending beyond the end wires 53-1, 53-8. Further turns of the erase wire A, C are used to erase preceding characters or an area to receive the next character. The head may be formed of interlocking strips which have a longer life than the wires (Figs. 8, 8A not shown). The head may be mounted on a perforated support connected to a vacuum pump so that the backing is pressed firmly against the head (Figs. 5, 7 not shown). A circuit feeding pulses successively decreasing in magnitude to the erase coils is described (Fig. 14, not shown), and a circuit controlling the recording of "1"s or "0"s in each bit position and the alteration of the parity bit to agree with the use of upper or lower case are described (Fig. 13, not shown). A reader for the recorded sheet has a drum 201 on which the sheet is mounted with each recorded line extending circumferentially around the drum and a read head 191 indexed from line to line. The sheet rests on a resilient surface on the drum and is held in place by clamping cams 209, 210. The drum carries a magnet 300 arranged to operate in succession switches 302, 303 as the drum rotates. The switches are situated to correspond to the start and the end of each recorded line on the sheet. The read head is indexed by a solenoid 232 operating a cam 231 and a toothed rack 229. The reader feeds an electric typewriter and uses counters shift registers and a comparator, (Fig. 18, not shown), to read the characters in succession, one per revolution of the drum.