Patent GB-956387-A (GB)
Title: Damping mechanism for planographic printing machines
Inventor: JAGER JOHANNES
IPC: B41F7/26
Filed: 1961-03-14
Abstract: 956,387. Printing machines. DRUCKMASCHINENWERK PLANETA VEB. March 14, 1961, No. 9285/61. Heading B6C. Damping liquid is conveyed from the distributer roller 15 to the plate cylinder 1 by a first applicator roller 2 excess liquid from which is carried by an intermediate roller 4 to a second applicator roller 3, the rollers 2, 3 and 4 being mounted in brackets 6 which can be moved peripherally and radially with respect to the plate cylinder to throw-off the applicator rollers. A planographic plate on the plate cylinder 1 is damped by forme rollers 2, 3 mounted in bearings 5 which are adjustable by means of spindles 8 in a pair of bearing plates 6. An intermediate roller 4 is also adjustably mounted in the plates 6 so as to contact the two forme rollers. The plates 6 have forked parts which engage hubs 7 of the plate cylinder bearings so that the plates can pivot about the axis of the cylinder 1 and also move radially in relation thereto. At the opposite side to the cylinder 1 the plates are supported by adjustable screws 13 when the rollers 2, 3 contact the cylinder 1. Eccentrics 9 mounted on a shaft 10 engage arm portions of the plates 6 and the shaft 10 can be rotated by means of an arm 11 and a link 12 so as to swing the rollers 2, 3 upwards and away from the forme cylinder. This may be done either manually or automatically following automatic stopping of printing owing to e.g. a fault in the sheetfeeding mechanism. In a stationary frame 14 is mounted a water trough 16. A fountain roller 17 dips into the water trough and is journalled in a pair of arms 18 secured to a shaft 19. An arm 20 also fixed to the shaft 19 carries a cam follower 22 which engages a twopart adjustable cam disc 21 mounted on a shaft 23 which is driven, through change-speed. gears, so as to oscillate the arms 18 and move the fountain roller 17 into and out of liquid transferring relation with a longitudinally recipro-. cating distributer roller 15. The roller 15 is driven from the shaft of the plate cylinder at the peripheral speed of the plate cylinder and the fountain roller is driven through gears 25, 26 from the shaft 23, the rollers moving in the directions shown by the arrows. The rollers 15, 17 are never in contact but approach close enough to each other for a film of damping liquid to be transferred from the one to the other. The distributer roller 15 contacts the forme roller 2 which transfers the greater part of the liquid on the roller 15 to the plate on the cylinder 1. The residue of the damping liquid is transferred from the roller 2 by the intermediate roller 4 to the forme roller 3 which ensures uniform distribution of the liquid transferred to the plate by the roller 2. The amount of liquid transferred to the distributer roller 15 can be regulated by adjusting the cam 21 or by varying the rotational speed of the shaft 23. Moverover, areas of the fountain roller may be wiped by squeegee rollers 30 in order to allow selective damping of the plate. When the forme rollers are tripped by the eccentrics 9 the roller 2 is raised from contact with the roller 15 and simultaneously a cam (not shown) engages extensions 28 of the arms 18 so as to prevent the roller 17 from moving towards the roller 15.