Study On Printability Of Paper And Its Test Method

The printability of paper is a compositive quality index relateing well to printing quality, including physical, mechanical, optical property. In this paper, image analysis, computer simulation and optical measurement were adopted to study the relationship between the printability of paper and printing quality.The purpose is to integrate theory with practice to analyze the relationship between printability of paper and printing quality. The primary conclusions are of academic and practical significance for promoting the study of printability and the development of science and technology in print industry.Computer simulation and image analysis technique wrer adopted to study the effect of smoothness and roughness of printing paper on the distribution of ink film thickness of printing.Results showed that the distribution of ink film thickness fits a normal distribution and its variance which represents the consistency of ink film thickness becomes smaller along with the increase of the smoothness, or becomes smaller along with the decrease of the roughness of the printing paper. Roughness is more sensitive than .smoothness in relfecting the effect of paper surface evenness on the thickness distribution of ink layer.The image analysis technique was adopted to study the surface strength of printing paper. The area ratio of picked speckles was defined to quantify the picking. Then the relationship between printing velocity and picking was discussed. Picking velocity wad defined by area ratio of picked speckles and based on that point area ratio method was compared with visual evaluation method in the testing of picking velocity. Furthermore, the relationship between area of picked speckles and printing velocity was also discussed as well as the distribution of area of picked speckles. It is proved the image analysis technique was more objective and accurate than visual assessment method in dealing with surface strength of printing paper and the results would be helpful in analyzing the reason of paper picking.Optical measurement was adapted to discuss the factors causing the Print-through (PT) of LWC paper in the aspects of printing technics and paper properties, including the thickness of ink film, printing pressure, the opacity of paper and ink penetration. The relationship between these factors and Print-through (PT) were also discussed and then the Print-through (PT) value caused by the opacity of paper, free penetration and forced penetration of ink were compared.The color of paper, which belong to the optical property was also discussed.Neugebauer equations is adopted to discuss the effect of colorimetric value of art paper on the printing color reproduction, including solid ink L*a*b* Values, gray balance and color gamut. The result shows the colorimetric value of art paper has a great influence on printing color reproduction process and it's necessary to adjust print process according to the colorimetric value of paper to obtain high-quality color reproductions. Furthermore, the research is also beneficial to adjusting of the color of paper in papermaking industry.