Patent GB-689843-A (GB)
Title: Improvements in printing presses
IPC: B41F11/00
Filed: 1950-01-23
Abstract: 689,843. Printing-machines. GIORI, G. Jan. 23, 1950, No. 1747/50. Class 100(ii) Rotary machines; inking apparatus.-A rotary printing-machine is constructed so that it can readily be adapted for printing multicolour intaglio or letterpress impressions from a single intaglio plate or from letterpress inked with several adjacent colours, or for offset printing from a single rubber blanket provided with several superimposed or adjacent designs and colours by a number of engraved cylinders. There are two co-acting cylinders of equal diameter, one serving as a sheetfeeder and impression cylinder, and the other is adapted to carry either printing plates or offset blankets. Mountings around the latter cylinder serve to carry either inking rollers or engraved printing rollers which can be adjusted axially, circumferentially, or transversely of their axes. For direct intaglio and letterpress printing a cylinder 2, Fig. 1, has opposed segments 4, 5 on which are clamped printing-plates 6, 7 which cooperate with an impression cylinder 38, these plates being inked in one or more colours by inking-rollers 21-25 mounted for adjustment in eccentric bearings in the machine frame 1. The surface of these rollers are cut away so that they only deposit ink at predetermined positions on the plates 6, 7, and are made as described in Specification 689,842. The rollers 21-25 are inked by identical groups of inking-rollers mounted on a carriage 51 provided with rollers 52 adapted to run along tracks on the frame 1; in the operative position, catches 54 on the frame engage pivots 53 on the carriage. Each group comprises a duct 55 and several distributing rollers, and is driven by gears and shafts connected to a transmission, parallel to the tracks of the carriage 51, which is driven from the motor of the press. Each group can be declutched. Each inking-roller 21-25 is mounted for axial and pressure adjustment as described below in connection with printing-cylinder adjustments. For intaglio printing only, the printing-plates 6, 7 are wiped by a cylinder 26 coated with, or made of, resilient material, rotated in the same direction as the cylinder 2, and, in known manner, has imparted thereto an axial reciprocation. The cylinder 26 is driven from the cylinder 2 but at a greater peripheral speed. It is mounted for adjustment in eccentric bearings, and is in contact with a metal cylinder 27 which takes the ink from the cylinder 26. The cylinder 27 is of larger diameter, and rotates faster, than the cylinder 26 from which it is driven, and is mounted in eccentric bearings. The ink is removed from the cylinder 27 by jets of liquid from nozzles 28, and a scraper blade 30, and is carried away by a pipe 29. The cylinder 27 is dried by warm air issuing from a further set of nozzles 34. In this kind of printing, sheets to prevent set-off are interleaved with the printed sheets on delivery, as described below. For offset printing, the inking-rollers 21-25 are replaced by engraved cylinders, and the printing- plates 6, 7 by rubber &c. blankets. Multicolour impressions with the colours either superimposed or side-by-side are transferred to the sheets. The wiping cylinders 26, 27 are rendered inoperative. Cylinder adjustments.-As shown in Fig. 9, each of the inking-rollers or engraved plate cylinders 21-25 comprises a shaft 207 mounted on ball bearings in a support 200. At one end a gearwheel 211, secured to the shaft, meshes with a gearwheel on the cylinder 2. The support 200 is eccentrically mounted in the frame 1, and can be rotated by gearing from a hand-wheel 203 to adjust the shaft 207 and cylinder toward or away from the cylinder 2. A fixed graduated cover 212 and an indicator 215 secured to the support 200 show the amount of adjustment made. The shaft 207 and cylinder can also be adjusted axially relatively to the frame 1 by means of a screw 204 at each end of the shafts. The cylinder comprises a tube 209 rotatably mounted on two end bushes 227 keyed to the shaft 207. Two spaced lugs 217 on the tube 209 carry adjusting-screws 219, 220 (not shown) which bear against an intermediate projection on the bush 227, whereby on manipulating the screws the tube 209 can be turned relatively to the bushes and shaft. A spring-urged locking means for the screws is provided. Gripper mechanism.-Sheets are fed by known means 39 to the impression cylinder 38, which is the same diameter as the cylinder 2 and driven therefrom, provided with opposed sets of grippers 50, 135, Fig. 6, secured to rockable shafts 136, 137, respectively. An arm 143 fixed to the shaft 136 is pivotally connected to a tube 146, and an arm 142 fixed to the shaft 137 is pivotally connected to a rod 144 slidable within the tube 146. A coil spring 151, arranged between the open end of the tube and a collar 149 on the rod, urges one set of grippers into the closed position and the other set into the open position. Two spaced fingers 138, 139 and 140, 141 are secured, respectively, to the shafts 136, 137, these fingers co-operating with stops 152, 153 fixed on the frame 1 near the sheetreceiving and sheet-delivery positions to close and open the grippers. Grippers 87 on an endless chain conveyer for delivering printed sheets comprises two independently operated sets of gripper fingers as described below. Set-off, preventing.-Printed sheets are delivered from the grippers of the impression cylinder 38 to sets of grippers 87, Fig. 1, on an endless conveyer 73 comprising two spaced chains, and delivered to a pile table 110, Fig. 3, which is automatically lowered by ratchet and gear-wheel means 112, 111, 190, 135. The grippers are cam-actuated to receive and deliver the sheets. Air blown from a series of nozzles 89 dries the sheets and maintains them parallel to the conveyer chains. Each set of grippers comprises two sets of gripper fingers 122, 123 secured on separate shafts which are rocked by separate cams at the receiving position 74 to grip the printed sheet, but at position 76, the grippers 123 only are cam-actuated to receive a plain sheet fed from a table 90: thus the pile 110 consists of alternate printed and plain sheets to obviate setoff, the printed sides of the printed sheets being uppermost. The set-off preventing sheets are fed over the table 90 one at a time, in known manner by means 91 against a stop 105 carried by a lever 96. The lever 96 is pivoted at 97 and, when rocked by a cam 93, lowers the stop 105 and co-operates with a spring-pressed roller 106 to feed a sheet to the gripper fingers 123. A second cam 94 rocks a pivoted lever 100 which, through a link 102, rocks a lever 103 pivoted at 97 to raise the spring-pressed roller 106 to allow a sheet to be fed to the'stop 105. The feeding means 91 is rendered inoperative when the machine is used for letterpress and off-set printing.