| 摘要 |
PURPOSE:To eliminate the staining of a dot matrix ink, water-flow and the solid printing in an image part and enable an accurate planography on a metallic plate, by a method wherein wetting water containing a water-miscible alcohol in a specified concentration is applied to a planographic plate in a specified film thickness. CONSTITUTION:A printing plate 4 provided with a fat-sensitive image part 2 and a hydrophilic non-image part 3 is fitted onto the surface of a form cylinder 1. Wetting water 5 contained in a tank 6 contains 0.5-5wt% of a water-miscible alcohol (e.g., isopropyl alcohol). Wetting water 5 is applied to the plate 4 in a film thickness of smaller than 1mum, preferably 0.2-0.8mum. Wetting water 5 is pumped up while adhering to the surfaces of rolls concurrently with the rotation of a chromium roll 7, is divided into water films 11a and 11b after passing through a nipping part between the roll 7 and a metering roll 8, the water film 11a is divided into water films 12a and 12b, and the water film 12a is transferred onto the hydrophilic non-image part 3 on the plate 4. |
