GB605012A - Improvements in printing and mechanism therefor - Google Patents

Abstract

605,012. Printing processes. GOSS PRINTING PRESS CO., Ltd. Dec. 11, 1945, No.- 33550. Convention date, Dec. 11, 1944. [Class 100(ii)] In a method of printing electrically such as is set out in Specification 604,012 in which the ink passes from a member bearing type or a design to a web, which does not touch the member, under the action of an electrical field, the web is charged electrically to a desired potential relative to the said member prior to passing to the design member and the electric field may be obtained solely by the charge on the web. As shown in Fig. 1 the web is first passed between static electricity eliminators 13, 14 of known kind which are earthed, and then the web is charged to the desired high potential by passage between rollers 15, 16 formed of conducting rubber connected to a source C of high potential comprising a terminal charged to a high potential relatively to an earthed terminal, the high potential terminal being connected preferably to both rollers 15, 16 so as to charge both sides of the web. The circuit includes alternating current mains 17, 18, a step-up transformer, and a rectifier. The static eliminator, is formed of metal mountings 13a, 13b, Fig. 4, between which extend an outer insulating tube of glass 13c, and an inner metal tube 13d in which are mounted carriers for needle point members 13e which rotate close to but out of contact with the web. The charged web passes close to the printing-roller 10 and is guided by a wedge-shaped block 22 of highly polished glass which defines one edge of the printing zone. For applying a second colour the web is passed over guide rollers 23, 24, and preferably the print is dried by a flame drier 25, after which the web is treated by static eliminators 33, 34, and one side of the web is charged to a high potential by a roller 35 similar to the rollers 15, 16. In addition to the wedge 42 near the printing-roller 30 a guide block 43 is used, and if a drier 25 is not used the wedge 42 is arranged so as not to touch the once printed surface. In a modification Fig.. 3, for multi-colour printing three units D, E, F are employed which are similar in construction to those described in Specification 604,012. Before the web enters each printing zone it is passed over guide rollers 58, or 58<1>, or 58", which may be arranged to charge the web to a high potential, or may be plain rollers which do not affect the web if charged with static electricity. The web then passes between members 56, 57 similar to the static eliminators, but the members instead of being earthed may be connected to some means at a predetermined potential with respect to the earth such as to a voltage divider energised by a high voltage supply unit such as is described above. The parts 56, 57, 58 may be reversed in which case the members 56, 57 are earthed and serve to eliminate static electricity, and the rollers 58 charge the web to a desired potential. Driers 59. 59<1> are arranged between the units D, E and E, F. U.S.A. Specifications 1,820,194 and 2,224,391 are referred to.