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Jan Claes

Bart Peter Verhoest

Marc J Scheerders

Bartholomeus Verlinden

Jos Bolders

Method and apparatus for DTR development of a lithographic printing plate of the type having a support possessing a natural deflection curvature under its ow weight and carrying an exposed silver halide emulsion layer in sandwiched relation an image receiving layer, wherein the plate is introduced into one end and removed from an opposite end of a DTR photographic developing bath for the emulsion layer. For such introduction, the plate is advanced through the nip of at least one pair of ingress feed rollers disposed one above the other above the bath surface along an ingress path that extends tangential to the nip at an angle of at least 5.degree. but less than 25.degree. to the horizontal and is unconstrained prior to its intersection with the bath surface. For its removal, the plate passes through a pair of egress feed rollers located above the bath surface along an egress path tangential to the egress roller nip at an angle of at least 5.degree. but not more than 25&gt;to the horizontal. While within the bath, the plate is guided, e. g. by elongated guiding bars, along a curved immersion path that has a positive curvature not substantially greater than the natural deflection curvature of the support and at its opposite ends is substantially continuous with the ingress and egress paths, The distance separating the nips of the ingress and egress roller pairs measured along the paths is less than the length of the plate. The guide bars can diverge laterally from one another.

Apparatus for developing a printing plate

Apparatus for processing rectangular sheets of photographic material in varying format sizes is equipped to calculate at least approximately the surface area of the sheets fed therethrough. For this purpose, the apparatus includes a sensor for determining a dimension, e.g. the length, of each sheet, a memory for storing the length and width dimensions of a plurality of sheet format sizes, and a control unit which compares the determined dimension of a sheet with the dimensions stored in the memory and upon finding a match therebetween gives an output signal indication of the surface area of the sheet. If more than one match is found, the unit gives an output signal corresponding to the largest format size having a dimension equal to the determined dimension. If no match is found by the control unit, the unit is adapted to give an output signal equal to the multiple of the determined dimension and the largest of the stored width dimensions or, alternatively, an output signal corresponding to a format size having a length greater than the determined dimension. The surface area indications can be used to regulate the replenishment of processing liquid consumed during processing.

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B 2640 Mortsel, Belgium

Jan Claes