Patent GB-834445-A (GB)
Title: Improvements in or relating to method and means for duplicating
IPC: B41L11/00
Filed: 1956-11-13
Abstract: 834,445. Copying documents. RITZERFELD, W., and RITZERFELD, G. Nov. 13, 1956 [Nov. 15, 1955; Nov. 21, 1955; Oct. 10, 1956], No. 34123/56. Class 100(2) [Also in Group XL(b)] In a method of printing whole pages, lines or sections from a master sheet by means of a duplicating machine, the cooperation of printing elements is selectively controlled by one or more electromagnets receiving control impulses from impulse transmitters allocated to lines or sections of the master sheet through one or more electronic elements. In a machine of the general construction disclosed in Specification 831,267, wherein the counterpressure roller is selectively tripped by a toggle mechanism under control of one or more electromagnets and including a control shaft rotating in synchronism with the printing drum, energization of a magnet 28, 28a or 28b, Fig. 3, conditions a lever system to operate the pressure roller under control of rollers on control discs on the shaft 34. Corresponding to each roller there is provided on the discs an induction magnet 68 having coils 70, 71 of 2,000-4,000 ohms. Keys T1-T15 when depressed prepare circuits to selected magnets 68. The discs carry a piece of'soft iron 69 which on passing a selected magnet generates a current across capacitors 72, 73 or 74 to control grids of thyratron tubes 75, 76, 77 to ignite one of the latter and energize the corresponding electromagnet. To each tube 75, 76,-77 is allocated an electric system comprising tubes 78, 79, 80 in push-pull relationship to quench the current in the former tube. In another form, Fig. 4, the magnets 28 act through rods 98 directly on the toggle pivot 18. A switching flange 102 carrying parts 104 of soft iron is rotated by bevel gearing 100, 101 in synchronism with the drum 1. The parts 104 pass in front of an induction magnet 110 controlling a thyratron tube actuating the magnets. The parts 104 carried on pin 103 are selectively protruded into operative relationship with the magnet by keys 108. For automatically setting the lines to be printed in the following cycle, a switching arm 122 on a locking flange 124 is provided rotatable on the control shaft 99. The flange is brought manually into desired position by a button 131, and after a cycle operates the next pin 103. Pawls 126, 127 operated by manual pins 132 constitute a stepping device to step the arm 122 with respect to the flange 102, when it is desired to print lines in a predetermined progressive order. In another form, Fig. 11, contacts K1-K13 under the control of keys T1-T13 are provided on a disc 151 for printing lines; and contacts K21-K33 under group control of keys 1-V or a disc 152 for printing headings or two or three lines together. Switching arms 156, 168 rotate synchronously with the drum. The contacts control two separate electronic systems. One system comprises a voltage divider 155, 158, 159 for transmitting an igniting impulse to a thyratron tube 154 by means of a capacitor 160, so as to energize a group of electromagnets 28. A booster device 161 causes a shorter response time for the magnet group. When an actuated contact K is opened, the decrease in voltage transmits an impulse to an amplifying tube 163 through a capacitor 164 to ignite a cancelling thyratron tube 165 and quench the tube 154. The second system is identical. In another form (see Group XL(b)), the impulse transmitters carried on the control disc are selectively lit electric lamps sensed by a rotating photo-electric cell which controls the tube.