| 摘要 |
637,105. Printing-surfaces. LUDVIGSEN, N. March 20,1947, No. 7671. Convention date, Jan. 17. [Class 100 (ii)] A method of manufacturing copy printing blocks from an original printing block comprises pressing, by means of a reverse die made from the original block, layers of materials of different colours, the layer adjacent to the die partially filling the hollows of the die so that the relief parts of the copy block are differently coloured from the hollow parts. A die 1 made from an original block is placed below differently coloured sheets 2 and 3 of material such as celluloid, impregnated cardboard, or an agglomerated substance such as resin, bitumen or fine sawdust. The sheet 2 has a thickness e equal to or less than the height h of the relief portions of the die 1. Pressure is applied to the sheets by a plate 4 so that the relief portions of the die 1 penetrate the sheet 2 and the two sheets become united together. The hollow portions 5, Fig. 2, of the block produced are of a different colour to the relief portions 6. In place of the sheets 2 and 3 layers of differently coloured powdered material may be used, the two layers becoming agglomerated under the combined action of heat and pressure. Alternatively, one sheet and one layer of powdered material may be used. In a modified method the die may be superficially coated in parts with colouring matter and a single sheet of material is then pressed on to the die. |
