| 摘要 |
PURPOSE:To enhance developability and adhesion and prevent scumming at the time of printing, by incorporating a specified amount of silicon atoms in an aluminum plate, in a photosensitive planographic plate provided with a diazonium salt containing photosensitive composition on the aluminum plate which has been grained, anodized and subjected to sealing with an aqueous silicate solution. CONSTITUTION:An aluminum plate used for producing a photosensitive planographic plate has a surface being degreased, grained, anodized and then subjected to sealing with an aqueous silicate solution. The aluminum plate thus treated has residual silicon in an amount of 0.9-4.0 mug/cm<2>. If the amount of residual silicon is less than 0.9 mug/cm<2>, there is a high possibility of defective development, particularly under severe developing conditions such as in the case of rapid development, development by a fatigued developing liquid or the like. Besides, adhesion of a photosensitive layer to a base is poor, and plate wear characteristics are poor. If the amount of residual silicon is more than 4.0 mug/cm<2>, the adhesion of the photosensitive layer to the base and the plate wear characteristics are poor, and preservation stability is also poor.
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