| 摘要 |
1,217,723. Printing-apparatus. MINNESOTA MINING & MFG. CO. 5 Jan., 1968 [6 Jan., 1967], No. 885/68. Heading B6C. [Also in Division G2] A planographic printing plate, stage C, comprises oleophilic image areas 10a which are ink receptive when dry and a bonded highly adhesive surface layer 16b which forms the non- image areas and is ink repellent, said layer having a release valve when dry of less than 100 gms. per inch whereby ink is received during printing in the image areas only and the use of water is obviated. Adhesiveness is stated to increase as release agent effectiveness increases, the release value of a surface being determined by measuring the force required to strip an adhesive tape from the surface at an angle of 180 degrees. The adhesive layer is advantageously a cured solid substantially linear organopolysiloxane. The image areas may be provided on a base layer of aluminium, the plate being imaged photographically (Division G2) as dipicted in Fig. 1 and Fig. 2 (not shown), or by electrical discharge techniques, Fig. 3 (no shown) in which image areas (32a) of the adhesive layer (32) are converted to an ink receptive state. The corona beam which converts the layer may be controlled by scanning an original or passing the beam through a metal mask or a photographic transparency. Alternatively an adhesive layer may be imaged by scribing freehand, by the use of mechanical instruments, or by overcoating with ink receptive material. Yet again, the adhesive material may be initially applied only in non-image areas. The base layer supporting the adhesive material may be transparent or opaque and of zinc, aluminium, paper or a polyester. |
