GB531790A - Web-fed printing presses - Google Patents

Abstract

531,790. Printing- machines. MACARTHUR, C. J. Aug. 2, 1939, No. 22384. [Classes 100 (i) and 100 (ii)] A multi-colour rotary machine for printing from intaglio cylinders is constructed with a number of impression cylinders 21, 22, 24, 26 which are mounted on fixed but adjustable axes and the web W to be printed is fed positively to and from the printing-couples by means of a common drive roller 14 which engages and drives a feed roller 12 and a delivery roller 21. The printing-rollers 20 are mounted so that they can be moved out of contact with the impression rollers, and can be rotated while out of contact with the web which may remain stationary when the printing-rollers are tripped. The printing- rollers are fitted with means whereby they may be restored to their original position of register with the web after being tripped. The cylinders 20 are driven by worm gearing from a pair of shafts 56 driven by bevel gearing from a common gear 60, the shafts 56 being associated with differential devices 230 which permit the drive to each couple to be adjusted for register purposes. The shaft 36, Fig. 4, of the priding-roller 20 is mounted in pivoted members 40 which are depressed by operating a quadrant 64 by a sliding rack 70. The rotation of the shaft 65 of the quadrant 65 brings into action a cleansing-roller 96, and also trips the doctor blade which normally acts on the inked surface of the roller 20. The impression rollers are formed with depressed parts corresponding to non-printing portions of the associated printing-cylinder, and this enables the printing-couples to be placed near together, as the wet impressions from one couple coincide with non-printing portions of the following couple. Guide rollers 260, 262, 264 are arranged between the couples and so the web travels in a polygonal path, the middle roller 262 being adjustable. A solvent recovery hood 266 is arranged beneath the rollers 260, 262, 264, and a suction conduit 270 leads to a reclaiming apparatus. A similar hood 272 is arranged near the guide roller 17, and a large hood 274 with a series of suction conduits 276 is arranged between the feed roller 14 and a drum 19 which may be fitted with heating or cooling means. The printing-cylinder is surrounded by a casing 80 to prevent escape of the ink solvent. To enable the printing-cylinder to be restored to its original position after being stopped, it is fitted with a notched disc 232, and when stationary one of the notches is engaged by a spring-pin 246 in a barrel 242 which can be secured adjustably in an arcuate slot 238 in a fixed frame. When the pin is engaged in a notch on the disc 232 an adjustable pointer is set to denote which notch is engaged by the pin. The pin is then withdrawn, and when printing is to be recommenced the roller 20 can be set to its original position and loss of register is avoided. Specification 215,509, [Class 100 (ii)] is referred to.