基于最小二乘法的不干胶材料柔性版印刷网点增大及补偿研究

Study on Dot Gain and Compensation in Flexograhpy on Self-adhesive Material with Least-Square Method

不干胶材料印刷品通常采用柔性版印刷,其印刷网点的变化影响着不干胶材料上图像复制的质量,因此需要进行网点增大补偿。本研究设计了柔性版印刷测试版,获取了不同印刷条件下的网点增大数据,基于最小二乘法,借助Matlab软件拟合了网点增大曲线,对比分析了印版硬度、印刷压力和加网线数对网点增大的影响。同时采用“网点实际增大补偿”算法对网点增大进行了补偿,并对补偿效果进行了模拟验证。研究结果表明,镜面铜版纸不干胶材料在柔性版印刷时应选用硬度偏大、加网线数适中的柔性版,并在尽可能小的印刷合压量条件下印刷;采用“网点实际增大补偿”算法对网点增大进行补偿,能较好地控制网点增大,还原印刷阶调。

Flexography is widely used for the printing of self-adhesive materials,and the changes in printing dots effect the quality of image reproduction on self-adhesive materials,so dot gain compensation is required.In this study,a testing plate was designed and dot gain data under different printing conditions was obtained.With the least-squares method,the dot gain curve was fitted using Matlab software.The effect of plate hardness,printing pressure,and the number of screening lines on dot gain was compared and analyzed.At the same time,the dot gain was compensated by using the“actual dot expansion compensation”algorithm,and the compensation was verified through simulation.The research results indicated that the flexible plates with high hardness and a moderate number of screening lines should be selected for flexography of mirror-coated paper self-adhesive material and printed under the condition of printing pressure as small as possible.In addition,with the“actual dot expansion compensation”algorithm,the dot gain compensation can be effectively controlled to restore printing tone.