GB891399A - Improvements in or relating to rotary relief-type printing presses - Google Patents

Abstract

891,399. Inking-apparatus. HARRIS-INTERTYPE CORPORATION. Dec. 5, 1958 [Dec. 5, 1957; April 25, 1958], No. 39303/58. Drawings to Specification. Class 100(2) A rotary printing-machine comprises a forme roller for inking a relief printing plate, said roller having a resilient inking member extending over at least a part of its surface, being driven at the same peripheral speed as the plate cylinder, and being dimensionally related to the latter so that the same areas of the inking member always apply ink to the same areas of the plate, and means are provided to maintain the axes of the roller and cylinder in precisely spaced parallel relation to control the pressure at which ink is applied. The forme roller is covered with a multiply make-ready sheet on which an impression is made by the printing plate. Plies proportional to the lightness of tone desired are then stripped away from parts of the sheet. A greater number of plies are stripped away where there is to be no printing as on areas corresponding to the outside areas of the plate. Alternatively the sheet may be one which swells with heat; the impression is made through a carbon sheet, the deposited carbon acting as a heat insulating during subsequent exposure to heat. The sheet is then covered with a resilient blanket. The forme roller is thus of varying effective diameter, and both receives ink from the distributing rollers in varying amounts over various areas, and transfers ink to the plate in varying amounts. Further, the distributing rollers may be at slightly different distances from the forme roller, so that some only of the former contact some parts of the latter. The forme roller and plate cylinder are formed with end bearing members rotating in contact, and are of such diameters that any point on the plate is always inked by the same point on the forme roller. With this arrangement, thin printing plates may be used which are shallow-etched, even the non-printing margins being shallow-etched, without undesirable ink transfer in non-image areas.