| 摘要 |
PURPOSE:To manufacture a metallic sheet for a lithographic printing plate having superior dot reproducibility at a low cost by spraying an acidic soln. contg. ferric ions as the principal component on a steel sheet of a specified thickness so as to regulate the average surface roughness and the number of HSC to a specified value each. CONSTITUTION:A steel sheet of 30-250mum thickness is etched by spraying an acidic soln. contg. ferric ions as the principal component so as to regulate the average surface roughness to 0.1-2mum and the number of HSC to 40-110 pieces per 2.5mm. The concn. of the ferric ions in the acidic soln. is about 10g/l- the solubility limit and the preferred pH of the soln. is about 0-5. A metallic sheet for a printing plate having superior hydrophilic property, water retentivity, dot reproducibility and printing resistance is obtd. The printing plate also has superior adhesion to a substance having a great affinity for ink.
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