Patent GB-875745-A (GB)
Title: Improvements in or relating to rotary duplicating machines
IPC: B41L11/00
Filed: 1959-07-23
Abstract: 875,745. Copying documents; feeding sheets. RITZERFELD, W., and RITZERFELD, G. July 23, 1959 [July 25, 1958], No. 25308/59. Classes 1CC(1) and 100(2) A rotary duplicating machine of the type wherein the whole of the master sheet or any line or section thereof may be printed at will comprises initial transport rollers arranged for conveying copy sheets into the desired printing position and electromagnetic coupling means arranged for controlling the drive to the initial transport rollers in dependence upon one or more registration markings on a copy sheet. As shown the duplicator comprises a printing drum 1 carrying a master sheet 2, an impression roller 12, feed rollers 23, 24 a damping device 25 and a roller 30 co-operating therewith. The roller 12 is carried by rocking levers 14 connected to magnets 19 whereby the roller may be brought into and out of contact with the drum 1 under the control of means not shown so that selected portions only of the master sheet may be printed. The printing drum 1 is rotated through gears 7, 8, 9 and a pulley 10 driven by a belt 11. The gear 7 is freely rotatable on the printing drum shaft and has secured thereto one side 4 of a single revolution clutch, the other side 5 of which is secured to the drum 1. The roller 30 is driven from a shaft 39 by means of gears 33, 34 and this drive is transmitted to the roller 24 by gears 31, 32 and to the roller 12 by a chain and sprocket drive 35, 36, 37. A sprocket 41 on the shaft 39 is driven continuously through a chain 42 by a sprocket 43 which rotates with the pulley 10. The sprocket 41 can be connected to the gear 34 by an electromagnetic clutch 40. An electromagnetic brake 44 is provided to arrest rotation of the gear 34 when the clutch 40 is uncoupled. A rotor arm 45 carrying contact pins 46, 47 is mounted on the printing drum shaft for rotation therewith and co-operates with contact strips 63, 64, 65. A photo-electric cell 22 is arranged so as to receive light from a lamp 21 directed at the cell and a lamp 20 directed at a copy sheet on the feed table, the light from the latter being reflected into the cell by the sheet. In use a copy sheet 48 is placed manually on the feed table with its leading edge in the nip of the feed rollers 23, 24 and a foot pedal is depressed which energizes a relay having the effect of breaking the circuit to the lamp 21, which is extinguished, and completing the circuit of a solenoid 59 which closes the single revolution clutch 4, 5. If there is no previous printing on the copy sheet 48 the drum 1 starts to rotate and the contact pin 46 engages the strip 63 which has the effect of sending a pulse to the electromagnetic brake 44, which is not needed, however, as the gear 34 is already stationary. The pin 46 next engages the strip 64 which completes the circuit to the clutch 40 whereby the rollers 24, 30, 12 are rotated and the copy sheet 48 is fed towards the nip of the drum 1 and roller 12, the device 25 being depressed by means of a cam 26 on the printing drum shaft to damp the copy sheet as it passes over the roller 30. When the sheet reaches the nip the pin 46 runs off the strip 64 and the rollers 12, 30, 24 cease to rotate. The sheet is then printed by the previously selected parts of the master sheet. As the drum 1 nears the end of its revolution the pin 46 engages the strip 65 which re-energizes the clutch 40 so as to rotate the rollers 12, 30, 24 and eject the printed sheet. If the copy sheet has been previously printed upon marks printed in the margin of the sheet and corresponding to each line of printing thereon interrupt the light beam from the lamp 20 so that when the foot pedal is depressed to commence printing and the light 21 goes out the photo-electric cell 22 fires a gas filled triode which energizes a relay having the effect of interrupting the circuit to the solenoid 59 and closing the circuit to the clutch 40. Thus the copy sheet is fed forward without rotation of the drum 1 until the marks on the copy sheet are clear of the beam from the lamp 20 at which point the gas filled triode is extinguished, the circuit to the solenoid 59 is completed and the circuit to the clutch 40 is broken. As the drum 1 starts rotating the brake 44 is applied momentarily to prevent the copy sheef from being fed too rapidly and thereafter the sheet is printed as previously described. Owing to the extra initial feed of the copy sheet the newly printed matter is in register with the previously printed matter thereon. Instead of printed markings in the margin of the copy sheets perforations may be used. The lamp 20 may be positioned so that the light beam therefrom is transmitted through the copy sheet instead of being reflected thereby.