GB1069139A - Printing press - Google Patents

Abstract

1,069,139. Printing-apparatus. STEVENS CORPORATION. Dec. 22, 1964 [Dec. 23. 1963], No. 52018/64. Heading B6C. Rotary printing machines.-A rotary offset printing machine comprises a main frame 11, a printing cylinder 20 rotatably supported by an auxiliary frame 106 which is removably attached to the main frame, an inking mechanism including an ink forme roller 63, means supporting said forme roller on the frame 11 for movement towards and away from the cylinder 20, and a stop device 78 carried by the auxiliary frame 106 and adapted, when the frame 106 is attached to the frame 11, for controlling the co-operation of the cylinder 20 and the roller 63. The auxiliary frame also carries the offset roller 17 and may be replaced by alternative frames provided with plate cylinders and offset rollers of selected diameters to produce the desired print length impression on the web 13. Each frame has its stop device 78 adjusted to provide the correct co-operation between the respective plate cylinder and the forme roller 63. The web 13 is guided over the impression roller 15 by a roller 14 and is tensioned by a compensating roller 16; the printing station shown may be preceded- or followed by other printing stations. Gear wheels attached to the shafts of the printing cylinder and the offset roller of each replacement unit are driven from a gear unit via an idler gear, Fig. 3 (not shown), when in position on the main frame. Damping apparatus.-Water is transferred from a fountain roller 21, mounted adjacent the curved forward end of a fountain 22, by a messenger roller 23 which co-operates with an axially vibrated roller 30, and water forme rollers 31, 32 apply the transferred film of water to the printing cylinder 20. The roller 21 is driven by an independent motor and the roller 23 is oscillated by a pair of pneumatic piston- and-cylinder devices 26, 27. A gear-wheel attached to the shaft of the roller 30 is driven from the gear of the plate cylinder via an idler gear, Fig. 3 (not shown). The rollers 31, 32 are mounted on levers 33, 34 which are pivoted about the axis of the roller 30. The levers are pivoted under the control of a pneumatic cylinder device 36 until they engage stop devices 40, 41. Each forme roller is provided with a bearing sleeve at each end which is guided along a guide edge on the respective lever so that the roller is correctly aligned with the roller 30 and the cylinder 20. Inking apparatus.-The ink is transferred from an incrementally advanced fountain roller 44 to three forme inking rollers 63-66 by a messenger roller 47, distributer rollers 54-56, 58 and 60, and vibrator rollers 57, 61 and 62. The forme rollers 64, 65 are mounted in a manner similar to that described with respect to the rollers 31, 32 and they co-operate with the cylinder 20 when a pneumatic cylinder 68 causes the lever 67 to engage a stop device 71 and the lever 66 to engage a stop device 70. The forme roller 63 is swung about the vibrator roller 61 into engagement with the cylinder 20 by a gear rack 75 operated by a pneumatic piston-and-cylinder device 76, 77. The messenger roller 47 is oscillated by a pneumatic cylinder device 53 and this cylinder and the cylinder 27 are both controlled by valves so that the messenger rollers engage their cooperating rollers in a yieldable manner. The stop devices 40, 41, 70, and 71 are each provided with four adjustable screw stop members and the pre-adjusted devices are adapted to be rotated by a chain, Fig. 3 (not shown), to present the stop member corresponding to the respective plate cylinder to the forme-carrying lever. A dial indicates the stop member and the cylinder being used. A gear attached to the shaft of the roller 62 is driven via the same idler gear which drives the roller 30. Cylinder tripping apparatus.-The offset cylinder is mounted in bearings carried by eccentric bushes and is tripped on actuation of a pneumatic piston-and-cylinder device which rotates the bushes via a linkage which is adjustable in length by means of a screw device, Fig. 2 (not shown). The said cylinder and the cylinders 36, 68 and 77 are actuated pneumatically under the control of three four-way valves, Figs. 12 and 13 (not shown), operated under the control of electric circuitry. Fig. 14 (not shown), connected so that the forme damping rollers engage the cylinder 20 before the forme inking rollers and so that the offset roller 17 co-operates with the cylinder 20 after it has been inked. The rollers are tripped in reverse sequence. The printing cylinder may be axially adjusted by rotating a cap member which is in threaded engagement with one of the bushes which supports the cylinder bearings, Fig. 5 (not shown).