主曝光时间对热显影数字柔印版参数影响的微观研究

Microscopic Studies of the Influence of Main Exposure Time on Parameters of Flexographic Printing Plate Produced by Digital Thermal Method

以数字感光树脂版生成柔印版的热显影技术无须使用任何溶剂。利用热显影制作数字柔印版包括以下步骤:背面曝光、激光曝光、主曝光、热显影、后曝光和光修整。本文采用光学立体显微镜研究了UV主曝光时间对热显影法制得的数字柔印版上再现的网点面积、网点直径和网点边缘系数的影响。同时,也研究了UV主曝光时间对印版图文质量和印刷网点轮廓的影响。显微镜研究结果定义了建立感光树脂版最佳主曝光时间的标准,这里感光树脂版是采用热显影技术制备数字柔印版材中使用的感光版。准确定义主曝光最佳时间可减少耗时的主曝光控制实验,以消除柔印版制版工艺中出现的误差。

The digital thermal technology of producing flexographic printing plates from photopolymer plates is one of the newest technologies. This technology allows to develop flexographic plates without the use of any solvent. The process of producing fiexographic printing plates by the digital thermal method consists of several main stages： back exposure, laser exposure, main exposure, thermal development, post exposure, and light finishing. The studies carried out with the use of optical stereoscopic microscopy allowed to determine the effect of time of main exposure to ultraviolet radiation on the dot area, diameter, and edge factor of halftone dots reproduced on flexographic printing plate produced by the digital thermal method, as well as on the quality of reproducing the surface and on the profiles of free-standing printing microelements. The results of the microscopic studies performed have allowed to define the criteria of establishing optimum time of main exposure of photopolymer plates used in the digital thermal technology of producing flexographic printing plates. A precise definition of the criteria for determining the optimum time of main exposure will enable to reduce the time-consuming control tests and to eliminate errors in both the process of manufacturing flexographic printing plates and in the printing process carried out with the use of such plates.