| 摘要 |
PURPOSE:To eliminate the need for carbon tissue, etching process of copper and continuous halftone positives and make machine plates simpler by adapting lithographic or typographic halftone positives and photogravure white line screens for photosetting type photosensitive resin plates. CONSTITUTION:The photogravure plate material 1 provided with a photosetting type photosensitive resin layer 1b on a substrate 1a is contacted with a lithographic or typographic halftone positive 2 and is exposed and printed like the arrows 3. This main exposure leaves the unset portions 4 of varying areas and depths as against the set portions 1c in the layer 1b. Next, the plate material 1 is contacted with a photogravure white line screen 5 and is exposed and printed. This auxiliary exposure leaves the unset portions 7 of varying areas and depths having the walls 6 of gravure cells. Next, the resin of the portions 7 are washed out by the developer, whereby the cells 8 of the sizes and depths corresponding to the areas of the dots of the positive 2 are formed. After drying, the machine plate whose layer 1b has been perfectly set by the post-exposure is obtained. |
