Patent GB-794549-A (GB)
Title: Improvements in printing machines
IPC: B41F11/00
Filed: 1956-05-16
Abstract: 794,549. Printing-machines. CRISSY, R. J. May 16, 1956 [May 25, 1955], No. 15225/56. Class 100(2) A rotary printing press comprises a main cylinder having a plurality of segmental areas on its surface, one of said areas having a plurality plate surface and another having an image receiving surface, a secondary cylinder tangential to the main cylinder, and an auxiliary cylinder also tangential to the main cylinder and arranged to receive an image from a plate surface of the main cylinder and to transfer it to an image receiving surface thereof, whence the image is transferred to a sheet passing between said main and secondary cylinders. The secondary cylinder 11 is driven by a motor. The cylinder 11 and the auxiliary cylinder 45 are connected to the main cylinder 10 by gears connected to their respective cylinders by Oldham couplings to allow tripping of the cylinders without disengagement of the gears. Sheets are fed over a table 20 between the cylinders 10, 11. The cylinder 11 is half the size of the cylinder 10, and is mounted on eccentric trunnions 16a to one of which is secured to a disc 27 spring-urged counterclockwise to separate the cylinders 10, 11, but held in engagement by a latch 25. In the absence of a sheet at a slot 29, a detector 28 acts on an arm 30 to rotate a shaft 31, a pin 32 on which tensions a spring 34 attached to the latch. At a given point of the machine cycle, a cam 42 acts on a roller 41 to cause a lever 37 momentarily to strike a surface 27a so as to release the pressure of a shoulder 26 against the latch 25. If the latch is conditioned by the detector 28 for release, it will move clear of the disc 27, and the cylinders will separate. The auxiliary cylinder 45 is also mounted on eccentric trunnions, one of which can be independently rotated by a hand lever to tilt the axis so as to adjust the pressure between the cylinders 10, 45 to be uniform throughout their length. At the opposite end or the cylinder 45, the eccentric trunnion is secured to a disc 54 fixed by screws 58 and slots 59 in adjusted relationship to a lever 57. The lever 57 is urged by a spring 60 into cylinder-separation position, but is held in cylinder-engagement position by a latch 65. The pressure on the latch 65 of a shoulder 57b is momentarily released by raised surfaces 85a, 85b of a cam 85 acting through a roller 83, lever 80 and adjustable screw 84 on a surface 57c. The latch 65 is conditioned for release at this time when a link 68 is moved to the right either by an arm 90 when the shaft 31 is rotated when no sheet is fed, or when a lever 95 is actuated by a pin 97a on the cam 85. By adjusting the times of separation of the cylinders 10, 11 and 10, 45, the diameter of the cylinder 45, and the number, size and position of the printing plates and the image-receiving surface on the cylinder 10, it is possible to (a) transfer a mirror image from a printing plate or images from more than one plate to the cylinder 45 and thence to the image-receiving surface, whence the image or composite image is printed on the. upper surface of a sheet the cylinder 11 acting as impression cylinders; (b) transfer a positive image from a plate or images from more than one plate to the cylinder 11, whence the image or composite image is printed on the lower surface of the sheet, the image-receiving surface of the cylinder 10 acting as impression surface; (c) by reducing the size of the cylinder 45, to transfer an image or two images from one or two small printing plates to the cylinder 45 and thence make a plurality of impressions on the image-receiving surface, which then nrints on the upper surface of the sheet. In all cases where images from more than one plate are transferred either to the image-receiving surface or to the cylinder 11. the images can be inked in different colours.