| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an original plate of a lithographic printing plate which particularly excels in plate wear resistance, while having an excellent stain resistance. <P>SOLUTION: The original plate of the lithographic printing plate is constituted by providing an image recording layer on a substrate for the lithographic printing plate which has on the surface a grained shape of a structure wherein a medium-wave structure of an average opening diameter of 0.5-5 μm and a small-wave structure of an average opening diameter of 0.01-0.2 μm are superposed. The substrate is obtained by a process wherein an aluminum plate is subjected to an electrochemical surface-roughening treatment with an electrolyte containing a nitric acid, so as to form the medium-wave structure, and then subjected to an electrochemical surface-roughening treatment with an electrolyte containing a hydrochloric acid and to an alkali etching processing in an etching amount less than 0.1 g/m<SP>2</SP>, in this sequence, so as to form the small-wave structure. The image recording layer is a photopolymerizable photosensitive layer containing a polyurethane binder. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
