Patent GB-1116681-A (GB)
Title: Improvements in or relating to duplicating machines
IPC: B41L39/00
Filed: 1965-06-17
Abstract: 1,116,681. Duplicating machines. A. B. DICK CO. 17 June, 1965 [24 July, 1964], No. 25702/65. Headings B6B, B6C and B6H. In a rotary lithographic duplicating machine, mechanism for feeding a master sheet to the printing cylinder and for applying an etching fluid to the master sheet are provided, and movement of the fluid-applying mechanism to operative position causes the master-sheet feeding mechanism to become operative. A rotary offset duplicator comprising master, offset and impression cylinders 42, 44, 46 geared together has a single control lever (70, Fig. 1, not shown) connected to two cams 384, 386, Fig. 16, and clockwise movement of the lever from a neutral position by successive steps causes rotation of the cams and (a) ink to be applied to the master by a roller 432, Fig. 15 (b) the master cylinder 42 to be moved into contact with the offset cylinder to transfer the image (e) the application of damping fluid to an axially-reciprocating distributing roller 450 contacting the roller 432 and (d) the operation of mechanism for feeding copy sheets to the machine. During normal running and whilst sheets are not being fed, the master cylinder 42 is repeatedly moved towards and away from the offset cylinder in known manner under control of the sheet-feeding mechanism. Subsequent anticlockwise movement of the lever 70 to the neutral position after a printing run causes the parts to revert to their original condition. The lever is now moved anticlockwise one step, in which position mechanism for ejecting the master sheet is operated, and then is moved a further step to a position which a blanketwashing apparatus becomes operative to wash the ink from the offset cylinder. When the offset cylinder is clear, the lever 70 is moved back to the neutral position in readiness for another printing run. The machine is running continuously during these operations. The master sheet is fed automatically as described below under the control of a mechanism 60, Fig. 3, for applying to the master a liquid or etchant conditioning the master to receive ink and dampening fluid. Applying etching liquid to the master to condition it for receiving ink and dampening fluid.- The mechanism 60 comprises a sponge 64 serving as a reservoir and an hexagonal pad 62 movable, with lost motion, by a lever 66 so that one face contacting the sponge is moved into contact with the cylinder 42. The pad 62 has a follower 124 resting on the cylinder shaft 120, so that during movement of the shaft 120 about eccentric pivots 122 for moving the cylinder 42 into and out of engagement with the offset cylinder 44, the pad 62 remains in contact with the cylinder. Either of the six faces of the pad 62 may be used, thus prolonging the life of the pad. Master-sheet feeding-mechanism.-When the lever 66 is operated to move the pad 62 into engagement with the cylinder 42, a projection 138, Fig. 3, thereon operates a lever 142, 146 connected to a latch 246 engaging a nose 250 on a lever 232 to hold a roller 234 out of engagement with a cam 230 on the shaft of the cylinder 44. The operation of the lever 142, 146 tends to release the latch 246 but such release does not take place until a high part 240 of the cam 230 engages the roller 234 to relieve the latching pressure between parts 246, 250. The lever 232 is now operated by the cam 230 and a roller 254 on the lever actuates an arm 178 on a shaft 198, Fig. 8. The shaft 198 carries front stops 188 which are moved out of the path of a master sheet previously placed by hand on a table 50, and also carries arms 174 mounting rollers 52 which are engaged with continuously-rotating rollers 54 to feed the sheet into grippers 212, 214 on the cylinder 42. To operate the grippers, a link 302, Fig. 3, is connected to the camfollower lever 232 and, through a lever 318, actuates a link 320 which causes axial movement of a cam 324, Figs. 13, 14 (not shown) into the path of a roller (352) on a gripper-operating lever (356). The gripper part 212, Fig. 8, comprises fingers in between which are fingers 220 for stripping the master from the cylinder as described later but which form with the fingers 212 an angle serving to register the front edge of the master. After one revolution of cam 230, Fig. 3, a secondary latch 282 engages the nose 250 to hold the lever 232 away from the cam 230 so as to render the master-sheet feeding- mechanism inoperative, and this latch remains operative until the operating lever 66 is returned to its initial position whereupon the latch 246 again becomes operative. Inking.-When the control lever (70), Fig. 1 (not shown) is moved to inking position, a part of the cam 384, Fig. 16, actuates a lever 418 which causes the inking roller 432, Fig. 15, to be moved into contact with the master cylinder. Transfer of image to offset cylinder.-After the next step of lever 70, a roller 462 on cam 386 actuates a lever connected to a link 474, Fig. 15, to swing downwardly a lever 486 effecting shifting of the cylinder 42 into engagement with cylinder 44. A spring-pressed arm 490 carries a pin 494 engaging an inclined edge 500 on an arm 498 fixed to the spindle 484 of lever 486, so that the pressure of the pin 494 tends to return the lever 486 to the inoperative position. The pin 494 may be engaged with notch 502 in the arm 498 when the lever 496 is moved manually to inoperative position. Dampening mechanism.-When the control lever (70) is moved forward another step, the cam 384 effects an additional movement of the inking-roller control lever 418, Fig. 16, and this causes a water-supplying roller 452, Fig. 15, to be moved into contact with an axially-reciprocating distributer-roller 500 engaging the inking roller 432. Control of sheet-feeding mechanism.-At the last-mentioned position of the control lever (70), a spring-pressed detent roller 398, Fig. 16, is in engagement with a detent notch 391 in cam 386, the notch 391 having an inclined edge 406 so that after further movement of the lever 70, the roller 398 tends to return the cams 384, 386 and lever 70 to their last previous position. During such further movement of lever 70, a pin 506 on cam 384 acts on a lever 510 to move a link 516, Fig. 15, connected to a sheet-feed control-lever 522 so as to set the sheet-feed mechanism in operation. Upon release of the lever 70, the pin 398 moves the lever and cams back to their previous position, but the lever 510 moves idly over the pin 506 so that the sheet-feed mechanism remains operative. Master-sheet ejection mechanism; sheet-delivery mechanism.-After completion of a run, the control lever (70) is moved anti-clockwise to its neutral position, and the various mechanisms revert to their initial positions. The lever 70 is now moved one step anti-clockwise from the neutral position. In its new position, a roller 524, Fig. 16, on cam 384 causes movement of a lever (534, Fig. 12, not shown) which through a link (546, Fig. 14) causes axial movement of a cam (552) into the path of the roller (352) on the gripper-control lever (356). The gripper 212 is thus opened and the fingers 220, Fig. 8, push the leading edge of the master sheet away from the cylinder 42. Stripper fingers (582, Fig. 24, not shown) direct the master between constantly rotating rollers (84, 86) feeding the master to a tray (82). Two sections (590, Fig. 25) of the lower roller (86) have projecting rings (604) which form longitudinal creases in the master to stiffen it and prevent it from curling. Cleaning the offset cylinder.-When a further anti-clockwise movement is given to the control lever 70, a roller 612, Fig. 16, on the cam 386 operates a lever 614, Fig. 15, which through a linkage 624 etc., operates an actuating lever 646 of a blanket washer 610. Specifications 1,116,683, 1,116,684 and 1,116,685 are referred to. Specification 1,116,685 describes a modification in which the master-sheet feeding mechanism is omitted, and the return of the control lever (70) from the washing position to the neutral position causes a switch to be opened to stop the machine so that a new master sheet can be fed by hand to the master cylinder.