Patent GB-311814-A (GB)
Title: Improvement in and relating to printing machines
IPC: B41F17/00
Filed: 1929-03-25
Abstract: 311,814. Oxford Varnish Corporation, (Assignees of Casto, L. V., and Webern, G. von). May 17, 1928, [Convention date]. Rotary intaglio offset machines.-A machine for printing wood grain or other patterns on large metal or other sheets comprises a printing- cylinder 10, Fig. 4, bearing an intaglio printing- plate, a transfer cylinder 11, and an impression cylinder 12 between which and the cylinder 11 the sheets are fed. To facilitate the removal of the cylinder 10, the ends of its shaft 13 are grooved to engage track bars 17, Fig. 2, over which the shaft can be rolled upon release of the shaft from the pivoted half-bearings 14. The rails 17 are pivoted at one end to the machine frame and their inclination can be varied by screws 22 swivelled in the ends of the bars and working in nuts 25 carried by pivoted struts 20. The machine is driven by a motor 40, Fig. 3, the shaft of which carries a worm driving a worm-wheel on the shaft of a gear 45 which meshes with a gear 46 secured to one end of the cylinder 10. The transfer roller 11 may be driven frictionally from the cylinder 10 or by a belt 36, Fig. 2, passing round drums 37, 38, the shaft of the drum 38 carrying a spur wheel 53, Fig. 3, meshing with a gear 51 on the shaft of the cylinder 10. The impression cylinder 12 is mounted in bearings 118, Fig. 3, guided in slotted members 117, and hung by bolts 121 from plates 119 adjustable by screws 120. Springs 122 between the bearings 118 and plates 119 allow the roller 12 to yield to inequalities in the thickness of the sheets to be printed. Slight play of the shaft of the roller 12 in its bearings 118 or between the bearings and the guides 117 may be permitted to allow angular displacement of the shaft relatively to the shaft of the cylinder 11 to maintain even pressure on the sheet if its thickness varies across its width. Printing-surfaces.-The cylinder 10 comprises end plates secured to the shaft 13 and connected by a sleeve 48, Fig. 4, over which is secured the thin etched intaglio plate 50. The ends of this plate are clamped between bars 55, 56 mounted in a gap in the cylinder and secured by screws to a bar 157 at the bottom of the gap. Inking-apparatus.-The plate 50 is inked by a roller 123, Fig. 4, rotating in an ink trough 124 into which ink flows continuously from an ink reservoir. The level of the ink in the trough 124 is kept constant by a stand pipe 127 through which surplus ink flows to a pump which returns it to the reservoir. The doctor 135, Figs. 2 and 3, is carried by a shaft 137 which is reciprocated axially by one arm 145 o a vertically pivoted lever, the other arm 144 of which engages in a grooved cam 140 driven by gearing from the shaft 13 of the printing cylinder. A spring 164 acting on an arm 166 on the shaft 137 holds the doctor in operative position. Set-off, preventing.-A cleaning scraper 136, Figs. 2 and 3, is arranged in contact with the transfer roller 11 and returns removed ink to the ink trough 124 by way of a trough 170 provided with a filter 174. The scraper 136 is carried by a shaft 138 reciprocated axially by one arm of a lever 148, the other arm of which engages in a groove in the reciprocating shaft 137 of 'the doctor 135. The doctor is held in operative position by the spring 164 acting on an arm 165 on the shaft 138 but is movable out of contact with the roller 11 by a cam 150 on a hand-actuated shaft 152 engaging an arm 163 on the shaft 138. Tripping arrangements. - The shaft of the transfer cylinder 11 is carried by a pivoted frame 34, Fig. 2, which is movable by a cam 151, Fig. 3, on the shaft 152 to move the cylinder 11 out of contact with the printing-cylinder 10 when desired. A stop 160 on the frame 34 co-acts with an adjustable stop 161 to determine the contact pressure between the cylinders 10, 11. Specification 328,970 is referred to.