纸张胶印品透印现象的预测与控制

为了有效预测和控制透印,提出采用抗透印值PTR来预测胶印品的透印性。以3种胶版纸和2种新闻纸为纸样,先测试它们的不透明度、油墨吸收性等性能,然后,在3组印刷条件下,利用IGT适性仪打印实地色块,并测量样条色块区与非色块区背面的色度值,考察了5种纸样的抗透印值PTR与印样透印量(用色差ΔE*ab表示)之间的关系。研究结果表明,适当降低印刷压力并提高印刷速度可降低印样的透印量;在相同印刷条件下,青墨印样的透印量略大于品红墨印样的透印量。另外,当待印纸样的抗透印值PTR增大时,印刷后纸样印区的透印量就会减小,特别是当测试纸样PTR值72%时,无论在何种印刷条件下,其胶印透印量均小于6,可在视觉上认定没有产生透印现象。

Forecasting and Control of the Paper Print-through Phenomenon on Offset Printing

In order to predict and control the print-through phenomenon, the value of print-through resistance （ PTR for short） was put forward to predict the print - through of lithograph. The opacities and ink absorptions of 5 given paper samples including 3 offset papers and 2 newsprints were tested, and then some solid color areas were printed on the paper samples with IGT printability tester under three sets of printing condition. Finally,the chromatic values of the negative side of color area and non-color area were measured, and the relationships between their PTR value and the print-through value （ calculated with △E＊ab ） was investigated. The results showed that lower printing press and higher printing speed were helpful to reduce the print-through phenomena. And on the same printing conditions, the print-through value of cyan ink print was slightly larger than that of magenta ink print. In＆amp;nbsp;addition, the increasing of PTR value could lead to the decreasing of the print-through value on the paper prints. In particular, no matter what kind of printing conditions, the print-through values were always little than 6NBS when the PTR values of those paper samples were larger than 72%, which seems to be the absence of print-through phenomenon on the vision.