| 摘要 |
PURPOSE:To develop the halftone images of a high line density with a high resolving powder by specifying the hardness of the roll on the side in contact with the toner image forming surface of the planographic printing plate formed by development of roll bodies. CONSTITUTION:The hardness of the roll 9 on the side in contact with the toner image forming surface 1a of the original plate 1 for planographic printing formed by the development of paired squeezing rolls 9, 10 is specified to >=20 deg. and <=70 deg. in the case of the development, by the wet process, of the electrophotographic planographic printing plate 1 for which a metallic base is used, by passing the printing plate through a developing device having the rolls 9, 10. A roll made of the material having the same hardness is usually used for the paired roll 10 in contact with the rear surface of the planographic printing plate of the squeezing rolls 9, 10, but the hardness thereof is not particularly limited. The uniform development with the high resolving power and the excellent fine line and halftone reproducibility particularly at the time of reversal development is executed in this way. |
