纸张转印墨斑检测方法初探

利用IGT印刷适性仪,在不同印刷条件下探讨了新闻纸、单面涂布白纸板和铜版纸转印墨斑的变化规律.结果表明,两种新闻纸的优化印刷条件为:油墨量0.10 mL、印刷压力650 N、速度0.4 m/s;主客观判定结果有差异,最少墨量时客观判定效果好,中等墨量时主观判定效果较好.两种涂布白纸板的优化印刷条件为:油墨量0.35mL、印刷压力200 N、速度0.3 m/s;铜版纸优选出的印刷条件为:油墨量0.50 mL,印刷压力500 N,速度0.2m/s.2人组及4人组主观判定结果的相关性较强;3种客观判定方法中,光谱法与主观判定的一致性最好,PTS法次之,灰度法最差,光谱法和PTS法有望作为评价纸张转印墨斑的新方法.

Study on Back Trap Mottle of Paper Printing

The back trap mottle in the print of different kinds of paper such as color offset newsprint, art paper and single coated paper was evaluated in this paper. Results showed that the optimized conditions of two kinds of newsprint are as follows: ink amount 0.10 mL, printing pressure 650 N, printing speed 0.4 m/s; there exists inconsistent correlation between objective quantitative assessment of mottling and subjective evaluation. Less mottle is obtained with the least ink amount by means of objective quantitative assessment, however, less mottle results are obtained with the medium ink amount when using subjective evaluation. The optimized conditions of the two kinds of single coated paper are as follows: ink amount 0.35 mL, printing pressure 200 N, printing speed 0.3 m/s. The optimized conditions of art paper are different. Results showed that there exists consistent correlation between 2 groups and 4 groups subjective evaluation of mottling. Among the three objective analysis methods, spectrum analysis correlates most closely with the visual results, then the PTS method. And the grey value method correlates at the least. So the spectrum analysis and the PTS method are expected to be the new methods for evaluation of the back trap mottle.