Patent GB-1379765-A (GB)
Title: Controlling a machine with signals derived from a pattern
IPC: H04N1/46
Filed: 1971-12-29
Abstract: 1379765 Automatic control of textile machines FRANZ MORAT GmbH 29 Dec 1971 [30 Dec 1970 (2)] 60486/71 Heading G3N [Also in Division H4] In the production of a design pattern by the optical scanning of a drawing and the generation of corresponding electrical signals, the signals are permanently stored in an information store and the stored signals are used to control a printer for printing out the pattern, the stored signals being changed, if desired, to correct errors arising during scanning or to make the pattern visually more pleasing. The stored signals may then be used for the control of knitting machinery either directly or by the production of control strips. Use of the process in the production of mosaic pictures is also mentioned. Scanner and printer. An artists drawing is mounted on a continuously rotating drum and is scanned by a scanning head containing three photodiodes associated with colour filters and mounted on a carriage which is moved in discrete steps by a stepping motor. A sheet of copy paper is mounted on the same or another similar drum and is associated with a printing head on the same or a separate carriage. This head includes three printer pins either directed at the same point on the copy sheet or separated by a predetermined distance along a straight line or on an arc of a circle. For scanning and printing with the same drum, interchangeable heads may be used; or two carriages on separate rails or on the same rail; or a single carriage with both types of head. Printing may take place after the whole pattern has been stored, or after each line. In the latter case it may occur while the drum completes a single rotation following scanning or may occur during every second rotation without intermediate movement of the carriage. Operation. Signals from the scanning head are passed to a colour evaluation circuit and then through a coding/decoding circuit, buffer storage unit and logic circuit to an information storage unit. The information storage unit is preferably a magnetic tape device but may be of the disc or drum type, having one reading or recording head per track, or a magnetic core storage matrix, punched card, or punched tape. During read out the signals pass back through the logic circuit, buffer store, and coding/decoding unit, and are then supplied to the printing head. Provision is made for the repetition of a part of each line and of a selected number of lines for motif repetition in the X and Y directions. When the printed pattern conforms to that desired the tape output may be supplied through the logic circuit and buffer store to a knitting machine or a device for producing control strips for the electronic control of such a machine. Between the evaluation circuit and the coding/decoding circuit, between the latter and the printer, or between the buffer store and the knitting machine a transposition circuit may be provided to bring the signals into a desired order. Preferably printing takes place at a slower speed than scanning and occurs after the whole design has been recorded. If scanning and printing occur at the same speed the buffer store may be omitted.  Central control unit (scanning) Fig. 8. Initially, all bi-stable circuits 891, 875, 855, and 859 are set at their Q 1 outputs by a clearing key. Scanning key 809 and START key 833 are then closed. Bi-stable device 891 then switches to its Q2 output. enabling AND-gate 813 to pass pulses from a rectangular pulse generator 805 through divider 811 to frequency converter 807 and then to synchronous motor 109 which continuously drives the drum carrying the drawing to be scanned. After a delay introduced by device 831, to allow the drum to attain its synchronous speed, gate 829 is enabled. A detector 121 associated with a marked disc attached to the drum produces a signal MZA when the leading edge of the drawing reaches the scanning head. This pulse is applied through AND- gate 829 to the 'Release' input of a release circuit 827 thus enabling divider 817 to pass pulses from generator 805 to the input of an X screen gauge counter 803. This is pre-set to the dot size required for the scanning, i.e. the elemental portion of a scanned line which is to be treated as a single item of information. When counter 803 reaches the set count it passes a pulse through AND-gate 819 to an X screen dot counter 804. This is pre-set to the number of dots required to completely scan a line of the drawing. The output from counter 803 also appears at terminal AT and is used as a scanning clock pulse in the buffer store (see below). When counter 804 reaches its pre-set count it produces an output A which passes through AND-gate 841 to the 'Block' input of release circuit 827, thereby interrupting the supply of pulses to counter 803. Since bi-stable device 859 is initially in its Q1 state, AND-gate 853 is enabled and an "end-of-line" signal is produced on line ZE. This signal prepares (see below) the buffer store for transferring the data to the magnetic tape store and when preparation is complete a signal is generated in the buffer store on line VZA. This signal starts the magnetic tape and starts a clock generator in the buffer store which produces clock pulses on line ZT, which are used to control the shifting of data into the tape store. The VZA signal also switches bi-stable device 859 to its Q2 output which enables AND-gate 865 to pass the ZT clock pulses to counter 804. When this again reaches its pre-set count its output A is passed through AND-gate 854 to produce a "counter stop" signal on line ZS. This signal causes control and address signals to be recorded on the magnetic tape following the picture signals, and the tape is then stopped. Meanwhile, the "end-of-line" signal produced on line ZE at the end of scanning the line of the drawing has been passed through AND-gate 863, delay device 879 and AND-gate 877 to the 'Release' input of release circuit 873 which permits the passage of pulses from generator 805 through dividers 868, 869 and storage counter 871 to stepping motor 107, which advances the scanning head carriage until a Y screen gauge counter 801 counts out and causes device 873 to block divider 869. Furthermore, the "end-of-line" signal on line ZE is passed to a Y screen dot counter 802. This sequence of events is repeated each time a pulse appears on line MZA from detector 121 until half the drawing has been scanned. Counter 802 then counts out and produces an output signal on "y/2", which is used to reverse the direction of the magnetic tape and to advance counter 883. Counter 802 is so constructed that if the number of lines to be scanned is odd it counts up to y/2 + ¢ before producing the "y/2" signal and at the same time produces a signal on line UZ indicating an odd number of lines. The UZ signal continues during the following line scan period to prevent advance of the scanning head, by switching bi-stable device 875, and to cause a blank information block to be recorded on the magnetic tape as the first block following reversal of the tape direction. During the return travel the remaining lines of the drawing are recorded. When the final line has been scanned and counter 802 has counted out to produce a second y/2 signal, counter 883, which is set to 2, also counts out and its output signal passes through AND-gate 893 to appear, after a delay set by device 889, as an "end switch off" signal on line E. Buffer store (scanning) Fig. 5. Signals from the scanning head, after passing through coding/decoding unit 4, are fed in parallel to shift registers 501, 503 which are stepped by the scanning clock pulses received on line AT from control unit 8. These clock pulses are also supplied to counter 507, the output of which appears after a count related to the number of storage cells in the shift registers. Upon the appearance of an "end-of-line" signal on line ZE a pulse generator 509 is started and rapidly shifts the stored data to the output ends of shift registers 501, 503. The "end-of-line" signal ZE is meanwhile stored in logic unit 6 and is used to advance a binary counter 529 so that it registers the address of the line of drawing immediately following the line stored in the buffer store. When counter 507 counts out its output signal starts tape unit 7, stops generator 509 and, after a delay through unit 515, resets counter 507 and passes to an AND-gate 517 which is already enabled by bi-stable device 521 in its Q1 state. The signal from gate 517 starts a pulse generator 511 which then supplies the clock pulses on line ZT to shift the data in registers 501, 503 into the tape store. The delayed output signal from counter 507 is also passed to the central control unit on line VZA. When the stored information has been transferred to the tape store, as determined by the counting of clock pulses on line ZT by counter 804, Fig. 8, the "counter stop" signal appears on line ZS and enables an AND-gate in logic unit 6 to pass the previously stored "end-ofline" signal from line ZE. This is stored on the tape to indicate the end of a line of drawing. After a delay in unit 537 the "counter-stop" signal ZS switches bi-stable device 535 to its Q2 state which enables AND-gate 533 to pass clock pulses to counter 527 and shift register 531. The address of the next following line of drawing is thus shifted from register 531 into the tape store and when this has been completed an output from counter 527 stops the tape, resets counter 507, stops clock 511, resets counter 527 and resets bistable device 535 to its Q1 output. Each line is stored in a corresponding manner until the first y/2 signal appears, indicating that half the drawing has been scanned. The y/2 signal is passed to logic unit 6 and is delayed relative to the ZE signal so that it is stored instead of the latter. The "counter stop" signal subsequently causes the y/2 signal to be recorded at the end of the information block. After delay i