GB1181730A - Duplicator - Google Patents

Abstract

1,181,730. Offset press. ADDRESSOGRAPH MULTIGRAPH CORP. 28 July, 1967 [29 July, 1966], No. 34909/67. Heading B6C. A rotary offset printing or duplicating press comprises a main frame 11 supporting an impression cylinder 17, a blanket cylinder 15 and a first printing cylinder 19, and an auxiliary frame 33 supporting a second printing cylinder 37 coacting with the blanket cylinder, at least a part of the second printing unit being adjustable between operative and inoperative positions. In the lithographic press illustrated in Fig. 1, first printing cylinder 19 has associated inking and damping trains 23, 25 mounted on a fixed frame 21; the second printing cylinder 37 has an associated damping train 39 mounted on frame 35 and an inking train leading to formation 45 wherein the ink unit 43 reciprocates on frame 35 to allow access to the second printing cylinder 37. This cylinder is generally used for applying a second colour image to the blanket, the second unit being rockable out of contact on shaft 209. Ink unit reciprocation.-The ink unit 43 may be moved backwards or forwards between stops 79, 81 and can be locked in printing position by handle 97 which causes teeth (83) fixed to frame 35 to engage matching teeth (85) on the ink unit 43 (Fig. 4, not shown). The ink forme rollers 49, 51 are each mounted in swivelling links (99, 99a), pivoted on the shafts of vibrator rollers 65, 67, arranged to enable the rollers to clear the top of the printing cylinder 37 on reciprocation of the ink unit, each link carrying a cam follower (101) coacting with a cam (103) carried on shaft (95), also operated by handle 97 (Fig. 4, 5, not shown). The pressure between the vibrator and forme rollers can also be released in a rest position by movement in the eccentric bearings (111) carrying the vibrator roller shafts. Removal of forme rollers.-Each forme roller 49, 51 is carried on a short shaft (130) in eccentric bearings (131) which are removably mounted in sockets in the side plates (Figs. 6-8, not shown). Drive mechanisms.-The main drive powers the blanket cylinder 15 on which is mounted a gear (53) which meshes with a similar gear (55) on the printing cylinder 37 when in printing position. The damping train is driven through toothed gears, the inking train through a belt and sprocket device (Figs. 2, 3, not shown). Operation controls (Fig. 11).-A single lever 143 controls a rockable shaft 145 mounted in an auxiliary frame 35, this shaft also carrying printing cylinder 37 and the mechanism for tripping the damping and inking forme rollers. At one end of the shaft is carried an ink cam 149, at the other end a moisture cam (151), (Fig. 12, not shown). Position I of handle 143 trips ink forme rollers 49, 51 through linkage 157, 159 to shaft 95, a similar mechanism tripping the damping roller 41; positions II, III successively bring the damping and inking rollers into contact with the printing cylinder 37, while position IV causes an eccentric section (177) of shaft 145 (Fig. 9, not shown) to turn and, through adjustable turnbuckle link 179, draw the master cylinder 37 into contact with blanket cylinder 15, where it can be locked by nuts 183, 185. Registration.-The entire shaft 145 is axially shiftable on frame 35 for lateral registration (Fig. 9, not shown) under control of knob 207 (Fig. 1). The auxiliary frame 35 is carried by brackets 215, (217) which pivot on shaft 209 which is rotatably mounted between fixed vertical side frames 29, 31. An eccentric sleeve (211) rockable on shaft 209 and received in bracket (217) can be adjusted in order to keep the blanket cylinder 15 and printing cylinder 37 in alignment by vertical shifting movement of the transverse shaft 209 (Figs. 13-15, not shown).