GB1372311A - Apparatus for electro-mechanically producing printing formes - Google Patents

Abstract

1372311 Facsimile apparatus DR ING RUDOLF HELL GmbH 1 Oct 1971 [2 Oct 1970] 45904/71 Heading H4F Electro-mechanical reproduction apparatus in which the scale of reproduction and the raster size of a printing forme 8 corresponding to a scanned original 1 may be independently altered, includes a double conical pulley 17 indirectly and adjustably driven by the motor 13 that rotates the support drums of printing forme 8 and scanned original 1 through a worm drive 12, and having two adjustable outputs which displace the photo-electric scanning head carriage 4 and engraving head carriage 10. A further worm drive 14 is arranged on shaft 6 which causes a conical pulley 15 to rotate and drive double conical pulley 17 via a friction rod 16. To adjust the reproduction raster size, i.e. number of raster lines per unit length, holes 41 and 101 are provided on the carriages 4 and 10 corresponding to the grooves in the conical surfaces, and rod 16 is suitably positioned, carriage 4 being axially moved by a rod 20 and carriage 10 by a rod 19, each driven by the lower half of the pulley 17. To adjust the scale of reproduction the positions of these rods 19 and 20 on pulley 17 may be adjusted, i.e. holes 42, 43, 102, and 103 in the two carriages. Frictional engagement between the pulleys and rods is improved by counter pressure pulleys 18, 21, 22, 23 and 24. Alternatively toothed racks and multi-stage toothed wheels (pinions) may be used. To maintain the aspect ratio constant adjustable gearing is interposed between one of the drums and its drive or alternatively the relative drum sizes are changed.