Patent GB-427824-A (GB)
Title: Improvements in or relating to rotary photogravure printing machines
IPC: B41F9/02
Filed: 1933-12-07
Abstract: 427,824. Printing-machines. ROBINSON, L. T. A., 13, Streatham Place, Brixton, London. Dec. 7, 1933, No. 34502. [Classes 100 (i) and 100 (ii)] Rotary intaglio-machines.-A rotary photogravure printing-machine is constructed with a number of printing units B, R, Y, S each supported by a pair of stands 77 above which are supported web guiding and drying devices permitting the web to be moved in either direction. The cylinders of the units can be rotated in either direction, and the web is drawn through the machine by means of draw rollers mounted in a frame 44 which can be placed at either end of the machine. The printing-couples do not feed the web. The machine may be arranged as in Fig. 3 to perfect the web in two colours, or as in Fig. 1 to print in one colour on one side of a web and three colours on the other. In either case a ground colour can be printed in addition to the single colour, and as well as a single colour an impression in an ink having a metallic appearance such as gold, silver, aluminium, or bronze may be printed on half the width of the web by employing a divided ink fountain and two scrapers. As shown in Fig. 1, the web from a roll 2 carried by a support 1 arranged between the units Y, S is passed over spring-mounted rollers 3, 4, between tensioning rollers 6, 7 to an impression cylinder 8 and forme cylinder 9, and then over a drying drum 10 heated by gas or electricity through drying-boxes 14, 15 with air inlets 16, 17 to an impression cylinder 12 and forme cylinder 13 which perfects the web. Before reaching the second couple the web may be led over an additional drying-drum 18. After receiving the second impression the web is led over further drying-drums and boxes, and guide rollers, and is led through two further printing-units R, B which superimpose impressions on that given by the unit Y. The printed web is finally drawn from the machine by a drawing-roller 363, Fig. 23, with which co-operate tapes 378 and a cutting disc 373. The roller 363 is driven from a shaft 362 through change-speed gearing, and the tapes 378 and the cutting-disc 373 are driven by gearing from the shaft of the roller 363. The web passes over a tensioning roller 377 before reaching the roller 363, and finally passes to a folder. When it is desired to perfect a web in two colours, the roll 1 is arranged as shown in Fig. 3 between the units R, Y, and the web is printed by the units S, Y, and then on the reverse side by the units R, B, the course of the web being indicated by arrows in Fig. 3. The printing-rollers employed are provided with detachable spindle ends to permit of easy removal from or replacement in the machine as described in Specification 406,325. The printing-cylinders are preferably of the kind described in Specification 402,405 in which the design sheet is secured to a longitudinally split printing- cylinder with segments provided with separating faces which enclose an obtuse angle, the apex of which forms the fulcrum about which the segments can rock relatively to tension the design sheet. To obtain correct register of the perfected impressions the printing-couples are driven by reversible means, and means are provided for adjusting circumferentially the printing or impression cylinders relatively to their driving shafts while the machine is at rest or in motion, and means may also be provided for adjusting angularly the drive of a printing-couple relatively to another couple, all as described in Specification 426,910. The forme cylinders are mounted so that they can be adjusted by means of toggle mechanism which can be adjusted manually or by fluid pressure, and the printing pressure is controlled by adjustable wedges all as described in Specification 407,719. The fluid-pressure control means is also arranged as in that Specification so that it can be operated from the side of any machine. The forme cylinders are fitted with scrapers constructed as described in Specification 406,325, the scrapers being reciprocated and controlled by resilient and flexible means which is yieldable in planes at right angles to each other, thus allowing of reciprocation of the doctor or scraper and movement towards and away from the forme cylinder. Specifications 362,983 and 363,035 also are referred to.