The Study On The Detection And Analysis Of PS Plate Quality

With an increasing of Pre-Sensitized (PS.) plate used in the field of offset printing. the issue of plate endurance and reproduction accuracy has been took into considered. The factors inluencing quality of the plate and rules by investigating the relationship among plate grain,oxic horizon and photosensitive layer of PS plate in this paper. The conclusion of the research could reduce the production costs of enterprises, improve the quality of plate and priomote the development of printing technology.According to tribology,structural mechanics and printing technology,the factors including plate grain,oxic horizon and photosensitive layer etc.of PS plate were comprehensive analyzed.The plate grain roughness and density on photosensitive layer, thephotosensitive layer and oxic horizon on the plate dot and the dot reproduction experiment were designed by the method of one-factor experimental, respectively. The plate grain roughness parameters,the plate grain density parameters,the thickness of photosensitive layer,the dot ,brightness and color values were measured by the tester. Curves and equations were obtained by using MATLAB (Matrix Laboratory)software and utilizing the least squares .The results showed that plate roughness and density of the plate grain have some influence on the photosensitive layer. The thickness of the photosensitive layer was increased by the increasing of the surface roughness of the plate grain, and the thickness of the photosensitive layer was decreased by the increasing of the density of the plate grain. Also, the roughness parameters on the thickness of the photosensitive layer was more obvious. The dot was not the same affected by the thickness of the photosensitive layer in case of high tone,middle tone and shadow tone. The appropriate thickness of the layer was obtained by the dot compensation curve.The stronger ink absorbency of the paper, the greater the effect on the dot gain ;the average color difference of the yellow ink smaller than other color in the tones range.Additionally, color difference has increasing tendency by dot gain when the tone from the bright to the dark .