GB615556A - Improvements in printing process and apparatus - Google Patents

Abstract

615,556. Printing. HUEBNER, W. C. March 28, 1946, No. 9631. Convention date, May 3, 1945. [Class 100(ii)] In the method of printing described in U.S.A. Specifications 1,820,194 and 2,224,391, in which the ink or colour passes from an inked printing-member to the material under the action of a magnetic or electric field of force and in which there is no contact between the printing-member and the material, the electrical circuits are arranged so as to charge electricity, the inked impression before it passes to the printing zone and also to charge with an opposite polarity the material to be printed on and also before it reaches the printing zone. Also, according to the construction shown in Fig. 1, the material 27 is brought into light contact with the printing cylinder 10 by means of rollers 28 between which is arranged the electrical attraction terminal 24 which is formed with a concave surface which serves to concentrate the lines of force as shown in Fig. 4 at a zone adjacent to the printing-member and in line with the electrical discharge terminal 18 which is mounted in insulating supports 13 integral with an insulating sleeve 12 which carries tubular supports 11 in which the printing-cylinder is mounted by means of an insulating sleeve 14. Two sources of electric high potential are used in Fig. 1, and are controlled by double pole switches S, SW. The switch S controls circuits for charging the terminals 18, 24 with charges of opposite polarity, and the switch may be set so as to connect the positive line 38 to either of the terminals. The switch SW controls means for charging the web 27 and the inked surfaces in such manner that the polarity given to the web corresponds to that of the terminal 24, and the polarity given to the inked impressions to that of the terminal 18. The web is charged by means of a pair of plates 31, 32, and the ink by means of curved plates 29, 30, and 49, 51, but the arrangement of charging plates may be varied, and plates may be replaced by a series of spaced bars or rods mounted on a flat or curved support, and in one modification where spaced bars are used the insulators 13 supporting the terminal 18 are arranged so as to be radial to the right-hand roller 28. In a further modification, Fig. 2, one switch DS is used to control the charging of the terminals 54, 58, which replace the terminals 18, 24, and also a flat plate 60 for charging the web and the plate 59 for charging the inked impressions. The rollers 28 are replaced by a cylinder 57 and the course of the web is tangential to the cylinders 53, 57. The terminal 58 extends close to the surface of cylinder 57, but the terminal 54 is mounted to leave a gap between its end and the ends of the insulators 55. The cylinder 57 is covered with a blanket 61 of plastic, rubber or other material, and this is surrounded by an arcuate terminal 62 which charges the blanket 61 and from this the charge is transferred to the web. The switch DS permits the terminal 54 and the inked impressions to be charged either positively or negatively, and the web and terminal 58 to be charged oppositely. In each form the arrangement is adapted to prevent defects which might be caused by promiscuous static charges. Specification 605,012 is referred to.