| 摘要 |
PURPOSE:To prevent stains to be generated around printed matters by arranging in upper face notch along an angled part of an edge, layering a photosensitive layer on an aluminum support body whose surface angle is specified, desensitizing an end of the support body, and treating the photosensitive layer with image forming exposure and developing processes. CONSTITUTION:In a planographic printing plate, an upper face notch is firstly arranged along angled part of edge of a square aluminum plate at opposing 2 or 4 sides. An angle of the surface of the notch with respect to the surface of the aluminum plate is set to 5 deg. or above. On the aluminum support body formed in this way, a photosensitive layer is layered. After the edge of the aluminum support body is desensitized, the photosensitive layer is treated with image forming exposure and developing processes. Or, after the photosensitive layer is treated with the image forming exposure and developing processes, the end of the support body may be desensitized. Thus, stains around printed matters will be prevented even in an initial time of printing and even if the number of printing sheets increase, and particularly a planographic printing plate optimum for printing newspapers can be obtained. |
