Patent GB-809700-A (GB)
Title: Magnetic recording apparatus
IPC: H04N5/782
Filed: 1956-08-14
Abstract: 809,700. Typewriters &c. CLEVITE CORPORATION. Aug. 14, 1956 [Aug. 22, 1955], No. 24815/56. Class 100(4) An apparatus for recording magnetic images of graphic symbols comprising a magnetic recording device presenting at the periphery thereof a plurality of recording elements disposed in an array and means for selectively energizing different ones of the elements in such a manner that the selected elements together form the outline of a symbol to be recorded has a rotary member for moving said recording device relative to a magnetic record tape so as tc record a line of symbol images on the tape as the rotary member is rotated Recording devices 21, Fig. 1, .on rotary drum 22 consists of blocks 19, Fig. 14, having thin wires 1-16 on the faces of the blocks, the wires being positioned so that by appropriate selection amongst them it is possible to produce all letters of the alphabet, each numeral, and binary symbols. Record tape 23, Fig. 1, has on its face adjacent the drum a layer of magnetic material, e.g. iron oxide. During recording, tape 23 is stationary and drum 22 rotates continuously, sweeping each device 21 across a given "line" on the section of tape over the drum. Current pulses sent through the wires from control pulse source 25, through amplifier 26 and recording pulse generator 27, induce magnetic flux batteries in the record tape. The latent magnetic image may be made visible by applying ink containing magnetic particles. Whilst all "lines" of a "page" may be recorded simultaneously, one "line" per revolution of drum 22 is preferred, to achieve this, stepping switch 24 selects one of the devices 21 at a time. The time interval between the groups of pulses for successive letters in a line allows the drum to rotate one letter space, thus a "line" is completed in half a revolution of drum 22. In the succeeding half revolution no printing occurs and after a complete revolution the next one of devices 21 is selected by switch 24. After a "page" has been completed record tape 23 is advanced an appropriate amount. The printing rate can be doubled by having two rows of recording devices 30, 31, Fig. 3, devices 30 being offset from devices 31 axially along the drum by a distance equal to line spacing, and adjacent devices 30, 31 being two line spaces apart Thus, recording may be carried out during both halves of the revolution of drum 32, Figs. 5, 6, show a further embodiment in which recording devices 35, 43, 44, slide in slots 36, 40, 42, so that one or two devices can record all the "lines" on a "page". The recording devices may be advanced from "line" to "line" in steps or continuously. In the latter case the lines of print will not be parallel with the edge of the record tape. To compensate for this the record tape may be fed on the skew and the recording device positioned so that the vertical axis of the letters is perpendicular to the lines of print. Alternatively, the lines can be recorded skewed with the letters perpendicular to the lines of print and a correction made during the transfer of ink from the record tape to the paper. Fig. 8 shows a further embodiment in which the record tape 50 moves parallel to the rotational axis of the drum 51, either one or two recording devices 52 being provided. Fig. 11 shows an embodiment in which recording devices 61 are spaced a "page" width apart and each records successive "lines" of a "page" during one revolution of drum 60. In both the embodiments shown in Figs. 8, 11, skewed lines may be compensated for by skewed paper feed. For printing a plurality of record tapes the embodiment shown in Fig. 12 may be used, the tapes may be skewed. In the embodiment in Fig. 13 (not shown), drum 70 carries recording devices 71 which are offset from one another axially a distance equal to the spacing between adjacent lines and equally spaced round the circumference of drum 70. As record tape 72 moves axially across rotating drum 70 the recording devices 71 move in succession across successive lines on the record tape and print thereon. The record tape may be skewed as previously described. Specification 806,288 is referred to.