GB602985A - Improvements in printing and mechanism therefor - Google Patents

Abstract

602,985. Printing processes. GOSS PRINTING PRESS CO., Ltd. Nov. 14 1945, No. 30504. Convention date, Nov. 15. 1944. [Class 100(ii)] A printing-machine in which ink is transferred from a plain or patterned cylinder 12 by means of an electrostatic field of force to a web 20 passing over a convex support 26 arranged with a gap between it and the cylinder 20 is provided with an electret 30 in the support 26. Electrets are the electrostatic analogue of permanent magnets and are formed of waxes &c. congealed in a strong electrostatic field. The block 26 is made of a high value insulator such as glass, quartz, rubber, porcelain. In Fig. 1 the design cylinder 12 is inked by rollers 16, 17, 18, and the web 20 passes over rollers 21, 22, 23, 24 at the same or different speed as the cylinder 12, and the printed design may differ in size from the pattern. Both the electret 30 and the cylinder 12 are earthed. In Fig. 5 the electret 30 is adjustably mounted by means of a bar 77 and screws, and-it is made of funnel shape. In a modification, Fig. 2, the 'electret takes the form of a tube 50 attached to an earthed metal cylinder 51, and the electrostatic action is controlled by a shield 53 of conducting material, which terminates just short of the closest approach of the tube 50 to the roller 12. In a further modification a plain coloured roller is used, and coacts with a patterned electret roller provided with insulating material such as 'red sealing wax, or hard rubber, in the depressed parts of 'the roller so that the periphery of the electret roller is smooth.