GB1497267A - Apparatus for treating sheet material - Google Patents

Abstract

1497267 Photographic processing apparatus AMERICAN HOECHST CORP 24 Dec 1974 [26 Dec 1973] 55757/74 Heading G2X To prevent the leading edge of a thin sheet (e.g. a lithographic or electrostatic plate) from being damaged when being fed to the nip of contrarotating treating members (e.g. brushes), a guide is provided which consists of a pair of plates extending wholly across the width of the sheet and extending towards, but not completely into, the nip. The nip may be formed by a pair of contrarotating members, Fig.1, or by only one contrarotating member and a stationary surface, Fig.3. In the first embodiment for treating both surfaces of a plate, Fig.1, a negative working lithographic plate or a charged, exposed, toned and fused electrostatic plate is fed by rollers 2, 4 to a guide assembly 6 comprising upper and lower plates 8, 10, which define a channel 16 which is kept flooded with developer supplied via conduits 18, 20. Plates 8, 10 terminate in fingers 22, 24 which extend close to the nip of contra-rotating bristle rollers 26, 28. The axles of rollers 26, 28 may be hollow to serve as developer conduits. The plate then passes between reciprocatable or oscillatable scrubber pads 26, 38 followed by rubber squeegee rollers (not shown). In a second embodiment, Fig.3, for treating one surface of a plate, a positive working lithographic plate is fed by rollers 2, 4 under developerdispensing spray nozzles 66 and through a guide assembly 6 comprising upper and lower plates 70, 68 of the form shown towards a single counterrotating brush 74. After leaving brush 74, the plate may pass between scrubber pads (not shown) and then between developer, transport and squeegee rollers 56, 58, under rinse spray nozzles 78, between squeegee rollers 80, 82, between gumapplicator rollers 84, 86, between air-dryers 90, 92 and finally between exit rollers 94, 96.