GB976135A - Improvements in or relating to rotary offset printing machines - Google Patents

Abstract

976,135. Rotary offset printing machines. W. RITZERFELD, and G. RITZERFELD. Dec. 5, 1962 [Dec. 22, 1961], No. 45901/62. Heading B6C. In an electrically energized push-button operated sheet-fed lithograph rotary offset printing machine in which selective line printing may be accomplished and which comprises an offset cylinder 220, Fig. 1, swingable between a printing cylinder 201 and an impression cylinder 234, the cylinder 201 mounts a master sheet 203 the image of which is to be reproduced on every printed sheet and a master sheet 204 from which only a selected line or lines is/are to be printed on each copy sheet. The cylinder 201 also mounts a series of radially movable segments 228, Fig. 3, which are projected from the surface of the cylinder by known electronic means (not shown) in order to project into contact with the rubber apron 221 carried by the cylinder 220 the portion or portions of the master sheet 204 containing the selected line or lines. Through electricallyoperated cams 218a, 218b, 218c, Fig. 2, and 218d, 218e (not shown), the used portions of the master sheet 204 are withdrawn into the interior of the cylinder 201 through the agency of a pawl 206 which is actuated by all or any of the cams 218 to thereby rotate a ratchet-wheel 210 fixedly mounted on the shaft 212 of one of a pair of drawn-in rollers 211, 213. Through the interengagement of toothed wheels driven from a single power source the three cylinders are rotated synchronously with an arm 290 which moves over a fixed contact bank 289 and in so doing initiates the various operations necessary for the automatic working of the machine provided the necessary keys T1 . . . T5 and TE of a control keyboard have been depressed. The keyboard is electrically connected to the bank 289 and comprises a key T1, T2, T3, T4 or T5 for controlling the current flow to the magnet of each cam 218 and an over-riding control key TE. Also connected in the circuitry involved are the electromagnets 303 ... 307 actuating the cams 218a ... 218e and electromagnets 231 and 325. The magnet 231 actuates the lever linkage eccentric mechanism 223, 329 and 330 for swinging the offset cylinder 220 aways from the cylinder 201 and into pressure engagement with the impression cylinder 234. The offset cylinder is normally spring-loaded by a spring 331 into close proximity with the cylinder 201 such that the master sheet 203 and the projecting portions of the master sheet 204 are in engagement with the rubber apron 221 thereof. The magnet 325 actuates a clutch arrangement 281, 287, Fig. 5, whereby the drive to the offset cylinder through the normal operational toothed wheels is disengaged whilst another toothed wheel train, also deriving from the single power source, engages and drives the offset cylinder forwards relative to the cylinder 201 to such an extent that the previous impression made by the master sheets on the cylinder 220 is no longer in register with that part of the cylinder 201 which now bears a fresh portion of the master sheet 204. After the offset cylinder is driven forwards by this amount, the machine is in position for printing a fresh portion of the variable text on the sheet 204 under the same fixed heading, the keys T1 and T2 being depressed if, again, two lines of the variable matter are required; otherwise the number of operated segments 228 and the corresponding ones of the keys T1 to T5 are re-selected accordingly. The rubber apron 221 of the cylinder 220 receives a fresh image of the heading and the new part of the variable text on a clean portion of the apron. When the apron 221 is completely used it may be cleaned by a washing mechanism 241. Instead of two separate master sheets one such sheet may be carried by the cylinder 201, the sheet parts not required for printing being then guided into the interior of the cylinder 201 in a looplike manner.