Patent GB-911534-A (GB)
Title: Improvements in or relating to apparatus adapted for use in printing designs on articles by an offset printing process
Inventor: JAMES DAVID RICHARD
IPC: B41F17/00
Filed: 1958-11-14
Abstract: 911,534. Printing on ceramic ware. MURRAY CURVEX PRINTING Ltd. Dec. 4, 1958 [Nov. 14, 1958], No. 36791/58. Divided out of 909,716. Class 100 (2). An offset printing machine, e.g. for ceramic ware comprises two offset printing members, a support for an intaglio plate and doctor means for an intaglio plate on the support, the intaglio plate being doctored alternately in opposite directions and the printing members engaging the plate alternately after each doctoring. As shown in Figs. 1, 3, an apparatus for stamping a Trade Mark or the like on the underside of an article comprises a machine frame 450 having a flat top 454 with a hole 456 over which the article to be printed is placed. A carriage 462 is reciprocable on rails 458 and slidably mounted therein are rods 496, 498 carrying at their upper ends offset pads 482, 484. A cylinder 510, fastened to the carriage 462 is reciprocable over a piston 512 mounted on a hollow pipe 514 through which air under pressure is supplied to the interior of the cylinder 510 at either side of the piston through outlets 518. A second carriage 464 to the underside of which is secured an intaglio plate 536 is reciprocable in guides in the upper part of the frame 450, the drive therefor being taken from the carriage 462 by means of racks 544, 540, mounted on the respective carriages and a pinion 542 mounted on the carriage 462. The carriage 462 carries inking apparatus 463 to be described hereafter. With the parts in the Fig. 1 position an article to be printed is placed over the hole 456 and a hold-down pad 688 is lowered into contact with the upper side thereof. Then pneumatic rams 470, 472 are operated so as to bring operating heads 506, 508 attached to the pistons thereof into contact with the lower ends of the rods 496, 498 and force the pad 482 up into contact with the article to be printed and the pad 484 up into contact with the intaglio plate 536. When the pads are lowered the carriage 462 is moved, by means of the cylinder 510 to its left-hand end position in which the pad 484 is beneath the hole 456 and the rod 496 lies over the operating head 504 of a further ram 468. The carriage 466 is also moved by the pinion 542 to a left-hand position corresponding to the right-hand position shown, the plate 536 being inked by the apparatus 463 as it moves from one end position to the other. Actuation of the rams 468, 470 now causes the pad 484 to rise into contact with the underside of a fresh article to be printed and the pad 482 to rise into contact with the inked plate 536. Spring plungers 534 minimize shock when the carriage 462 reaches its end positions. The apparatus shown in Fig. 8, for printing on the upper surfaces of articles, such as ceramic ware or instrument dials, is similar to that shown in Fig. 1, but with some of the parts inverted. Thus, two offset pads 482<SP>1</SP>, 484<SP>1</SP> are mounted in a carriage 462<SP>1</SP> which can be moved to positions in which one or other of the pads is over a hole 456<SP>1</SP> in a cover-plate 454<SP>1</SP>, a second carriage 464<SP>1</SP> carrying an intaglio plate 536<SP>1</SP> on its upper surface and being reciprocable by the carriage 462<SP>1</SP> through racks and a pinion. Four articles to be printed are carried on a rotatable table 772 which is rotated through a quarter of a revolution after each printing so as to present a fresh article at the printing station. Inking apparatus.-The inking apparatus for the intaglio plate 536, Figs. 1, 3, 4, comprises a trough 626 pivotally mounted at 628 on a trunnion block 608 carried by the carriage 462. An ink applicator having ends 668, 670, is mounted on a shaft 644 rotatably mounted in the walls of the trough and carrying an upstanding lever 672. When the carriages 462, 464 are in their right-hand end positions, as shown in Figs. 1, 4, the lever 672 engages a spring stop 674 attached to the frame 450, so that the end 670 of the applicator is raised out of the trough and deposits a line of ink on the plate 536. The trough 626 is normally held in an horizontal position by spring-pressed plungers 646. As the carriage 462 moves to the left, Fig. 3, a cam-follower 636 carried by a rocking member 630, also pivoted at 628, engages a cam track 632 and tilts the member 630 so that an arm 640 thereof engages one of two screws 644 carried by the trough 626, causing the latter to tilt and bring a doctor blade 652 mounted at one end thereof into position to wipe the intaglio plate 536 as it passes over. When the carriages are in their left-hand end positions the end 668 of the applicator deposits ink on the plate 536 and the trough is subsequently rocked in the opposite direction so as to bring a doctor blade 654 thereon into position for wiping the plate 536. In the embodiment of Fig. 8, the intaglio plate 536<SP>1</SP> is mounted in a well 762 in the carrier 464<SP>1</SP>. Before use ink is poured into the well to a depth of about # inch, the ink being of such a consistency that when wiped from the surface of the plate 536<SP>1</SP> to one end of the well it builds up to form a ridge and flows only very slowly back again. Pivotally mounted on a trunnion block 608<SP>1</SP> carried by the carriage 462<SP>1</SP> is a bracket 764 normally urged into an horizontal position by spring-pressed plungers 646<SP>1</SP> and carrying two doctor blades 654<SP>1</SP>. A rocking member 630<SP>1</SP>, similar to the member 630, Fig. 8, co-operates with a cam track 632<SP>1</SP> to rock the bracket 764 as the carriage 462<SP>1</SP> moves and to bring the appropriate doctor blade 654<SP>1</SP> into engagement with the plate 536<SP>1</SP> to spread the ink thereover and simultaneously wipe off the surplus from the image area of the plate.