Patent GB-1041265-A (GB)
Title: Circumferential registration control
Inventor: THIEDE PAUL WILLIAM
IPC: B65H23/188
Filed: 1963-07-02
Abstract: 1,041,265. Automatic registration systems. HURLETRON Inc. July 2, 1963, No. 26275/63. Heading G3R. [Also in Division H3] Lack of registration between marks on a moving web 30 and e.g. a print cylinder 150 is measured by the change in amplitude of an "inspection" signal representing rotation of the cylinder, between the receipt of the mark pulses. The "difference-in-amplitude" signal controls a hydraulic servo mechanism 80 actuating compensating roller 50. Cylinder Signals Two photo-cells and a light source mounted in a housing 200 on the cylinder shaft cooperate with apertures in discs carried round by the shaft to produce the inspection-zone and cylinder pulse signals. The aperture for the inspection-zone is arranged to produce a signal A which increases linearly with movement of the drum for about 20 degrees rotation during which registration is detected, and the cylinder pulse mask is fixed relative to it to produce a pulse C about half-way along the rising slope of A. The detailed construction of this apparatus is described with reference to Fig. 2 (not shown); provision is made for rotation 4 of the rings carrying the photocells CR1, CR2 and light unit relative to the masks 284, 286 on the cylinder shaft for initial setting up. The adjustment may be made manually by knob 222, or remotely by motor 236 driving a gear engaging the ring 282. The shape and position of the signal pulses during three revolutions of the drum is shown in Fig. 6; first revolution in synchronism; second revolution, web pulse arrives late; third revolution, web pulse early. Control Signal Circuits The inspection-zonesignal is amplified at 410 and applied to the cylinder and web memories 510, 520 to charge capacitors therein in a positive direction, waveforms, E, F, Fig. 6. until the arrival of cylinder web reference pulses C, D. The signals attained by the respective capacitors (C47, C53, Fig. 5 not shown) are applied to the inputs of a differential amplifier 530 to control the valves of the hydraulic servomechanism. This amplifier is provided with feedback by variable resistors 57, 61 Fig. 5 (not shown) to control the sensitivity and provide a certain degree of damping. The cylinder and web reference pulses are processed in shapers 430, 450 by differentiating the leading edge of a square pulse to produce spiked signals C, D, which trigger cylinder and web gates 440, 460 to apply an output on leads 441, 461 to terminate the charge of the memory capacitors. At the beginning of each revolution as soon as the inspection-zone-signal reaches a small predetermined value, it triggers the reset unit to generate a reset pulse B which resets the cylinder and web gates and the memory circuits so that the storage capacitors start with equal fixed values of negative charge. Fail Safe Circuit The fail-safe-gate is triggered by the reset pulse to provide an output to the fail-safe-relay circuit, which will cause the relay to operate and disconnect the automatic control in a short time (depending on the time constant of R63, R64, C63 Fig. 5, (not shown), unless the failsafe-gate-signal is removed. The fail safe gate can only be "reversed" by simultaneous inputs from the web gate, culinder gate and inspection zone amplifier. i.e. there has to be an inspection zone signal, and web and cylinder pulses have to be received during the inspection zone period.