| 摘要 |
PURPOSE:To facilitate exfoliation of a negative for exposure and printing after vacuum contact and printing by using an organic foaming agent containing a hydrazo compound and a photosensitive regin to form the photsensitive layer of a photosensitive printing plate and thermally decomposing the agent to roughen the layer surface. CONSTITUTION:The surface of an Al plate or the like is roughened and made hydrophilic. To a photosensitive resin are added an organic foaming agent such as hydrazodicarbodiamide in an amt. of about 3-30wt% to the amt. of the resin and a foaming agent decomposing assistant such as urea or a ures derivative in an amt. of about 30-60wt% to the amt. of the agent. The resulting composition is coated onto the Al plate and dried by heating to form a photsensitive layer. At this time, the agent is thermally decomposed to provide a rough surface having a height difference of about 1-10mu, a protrusion diameter of about 2-20mu and an interprotrusion distance of about 0.1-1.5mm. Thus, a printing plate is easily manufactured which enables short-time easy contact of a negative and gives a clear image closely following the negative without exerting unfavorable influence on the printability. |
