| 摘要 |
759,059. Automatic registration control systems. CROSFIELD, Ltd., J. F. Aug. 13, 1954 [Jan. 14, 1954], No. 1164/54. Class 38 (4). [Also in Group XL (c)] Rapid correction is obtained in a registration control system for, e.g., printing-machines, by applying a large initial shift followed by a smaller reverse shift which leaves the net shift equal to the original error. As described, the two corrections are initiated, e.g. every fifteen revolutions of the printing-machine by a timing (pulse-counting) circuit. The magnitude of the shifts is determined by the rate of discharge of capacitors, charged by the error signal (as determined, e.g., by a photo-electric scanner). Initial shift.-Relay A is energized by a timing circuit, Fig. 4 (described later), to charge a 2 ÁF. capacitor 12 and a 4 ÁF. capacitor 13 in parallel from the error signal at terminals 10, 11. Relay A is then released to connect the larger capacitor 13, across the grids of a double triode 46 to operate either relay B or relay C, according to the sense of the error to (i) start the correction motor, Fig. 5, and (ii) connect the capacitor 13 through a resistor (55 or 59) to a point 57 of relatively high-potential, so that the capacitor discharges linearly determining the time (i.e. amount) of initial shift. Reverse shift.-After relay B or C is released by the discharge of capacitor 13, the timing circuit releases a relay to (i) reverse the connections to the correction motor; (ii) connects the 2 ÁF. capacitor 12 in place of the 4 ÁF. capacitor 13 to cause reverse rotation of the correction motor, for half the previous time. Timing circuit.-Negative pulses generated every revolution of the printing-machine are squared by a " flip-flop " connected doubletriode 15, and positive pulses from anode 19 are integrated by capacitor 31 and diode 33 to operate relay F after a predetermined number of pulses. Relay F (i) applies a " holding " bias to the double-triode 37, (ii) energizes relay A and charges a delay circuit capacitor 40 for controlling the reverse shift, (iii) discharges capacitor 31 thereby releasing relay F for the start of another cycle. Meanwhile, charging of capacitor 40 has energized relay H (in the cathode circuit of a double triode 44) causing its repeater, Fig. 5 (not shown) to (i) connect the correction motor to the control relays B and C for initial shift, and (ii) select capacitor 13 (Fig. 3). The release of relay H and its repeater to connect for reverse shift is determined by the time for capacitor 40 to discharge, which is affected by the speed of the printing-machine as represented by negative pulses from the anode 17 of the " flip-flop " circuit which are stored by capacitor 76. The capacitor 40 discharges fairly rapidly to the potential of tapping 80 in one cathode resistor of double-triode 44 (which is determined by the potential of capacitor 76), and then more slowly through resistor 52. Specification 641,830 is referred to.
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