GB1304457A - - Google Patents

Abstract

1304457 Printing apparatus MINNESOTA MINING & MFG CO 12 March 1970 [13 March 1969] 12016/70 Heading B6C Sharp-edged impressions are produced on a tacky-surfaced tape or sheet material 25 by causing the material to adhere to the face of an intaglio printing block 20 or 42, or of a plurality of such blocks, held in a carrier 11 or 41, and causing a powder ink 24 to adhere to the tacky surface in the pattern of the intaglio image. The ink may be held in deep intaglio wells, and be applied by inversion of the block-carriersheet assembly, or by vibratory, electrostatic or magnetic means. Alternatively the intaglio image may communicate with the interior of the carrier 41, where a single body of powder ink supplies all parts of the image. The block 20 or 42 may be of aluminium, zinc, steel, copper, acrylic plastics, nylon, phenol formaldehyde resin, metal-plated plastics material or plastics material incorporating electrically conductive metals or compounds, and may be held in the carrier by friction, by magnetism or by engaging grooves 50 with flanges 44. The ink may have a particle size of 5 to 60 microns, and be either black or coloured. It may be a powdered thermoplasic ink, or may contain microcapsules or reflective beads. A preferred ink contains an epoxy resin, magnetite, carbon black and SiO 2 . If the sheet 25 is of cellulose acetate, raised characters 30 may be produced on its side away from the ink by heating it after application of the ink and before removal from the block. Transfers may be made by printing on silicone material which releases the ink to a more tacky surface, or by printing on an elastomeric surface with a thermoplastic ink which can be released by application of heat.