GB1347118A - Contact copying apparatus - Google Patents

Abstract

1347118 Contact printing apparatus KALLE AG 19 April 1971 [16 April 1970] 26916/71 Heading G2A A contact copying apparatus comprises a rotatable copying cylinder 21 and first, second and third feeding devices e.g. belts 13, 14 and 15, for feeding an original and copying material through an exposure zone positioned around part of the periphery of the cylinder, characterized in that a light beam 18 is screened out of a copying light source 19, passes through a transfer zone positioned between the first and second feeding devices and strikes at least one photo-electric cell 20, the light beam being modified by the passage of the original therethrough and serving to control one or more of the following (a) selection of copying material of an appropriate width (b) selection of copying material of an appropriate length (c) selection of an appropriate exposure time and (d) alignment of the copying material with the original. The original 10 enters the apparatus at a slit 12 and is fed from the first 13 to the second 14 feeding device, which are in the form of endless belts, across a light-impermeable plate 16 having a transverse slit 17 through which the light beam 18 passes. As the original cuts the beam 18 the photo-cell, or bank or photo-cells 20 register (a) the width and front and rear edges of the original, thus determining the length and width of copying material required; (b) the transparency of the original, to determine the copying speed; and (c) the positioning of the lateral edges of the original to determine any lateral displacement of the copying material required. The copying material is fed from rolls 41, 42, 43 of varying widths housed in a casing 40. A sheet 23 of the determined width and length is automatically cut and fed on to a belt 46. The belt 46 is supported on a carriage 45 which may be displaced laterally in dependance on the measured displacement of the original, so that as the original 10 and sheet 23 meet at the nip 22 between belt 14 and a belt 15 forming the third feeding device, they are exactly superimposed. The belt 15 conveys the sheets around the copying cylinder 21. After exposure the original and copy are separated, the former being ejected into troughs 29 or 31 and the latter passing to a further belt 32 which conveys the copy through a development section 36 and ejects it into troughs 38 or 39. The belts 13, 14, 15, 32, 46 may consist of a single perforated belt or a plurality of parallel belts. They are air permeable and the cross hatched regions indicate areas of suction for retaining the original and copy on the belts. In an alternative mode of operation the direction of the belts is reversed and an original 50 superimposed on a copy sheet 51 is fed manually from a desk 49 directly to the exposure zone without the original passing through the light beam.