GB819817A - Improvements in or relating to printing machines - Google Patents

Abstract

819,817. Printing machines. WEBER, G. E. May 31, 1957 [May 31, 1956], No. 16862/56. Class 100(2) In a printing machine an ink carrier web of plastic or like material is stretched by air suction over the type faces of a forme to provide an ink covering therefor by which printing can be effected. As shown a flat-bed printing press comprises a stationary platen 6 and a forme carrier 2 mounted on a base 9 which is slidable on vertical guides. An endless web 5 of thin plastic or rubber material e.g. polyethylene or P.V.C. from 0.001 to 0.002 inches thick, is carried on rollers 18, 19 and passes between the forme 4 and the platen 6. The outside of the web 5 is supplied with ink from a fountain 22 by transfer rollers 23 and the roller 18 is driven intermittently in synchronism with the forme so that the web advances to bring an inked portion thereof under the forme 4 between each printing. A passage 7 in the forme carrier 2 communicates with an air channel 8 in the base 9 connected by a hose 14 to a suction pump. A valve plate 13 apertured at 12 and mounted on the platen 6 co-operates with a plate 11 apertured at 10 and mounted on the base 9 so that the channel 8 is cut off from the suction hose 14 until just before the press closes to effect printing. The apertures 10, 12 then come into register and the web 5 is sucked tightly against the type faces of the forme 4 so that ink is transferred from the web to the sheet to be printed which is supported by the platen 6, only in those areas depressed by the type faces. A frame 1 surrounds the forme 4 and serves to make an air-tight enclosure with the web 5.