グロス調塗工紙のオフセット印刷物で発生するインキ剥がれのメカニズムに関する研究

抄録

Ink peeling is a quality problem in printing where white dots appear sporadically on the printed surface. With several types of printers, when gloss-coated paper is printed with sheet-fed offset press, ink peeling occurs on the overlaid part of the printed surface of the upper part of the piled up printed sheets. In this study, we attempted to reproduce this phenomenon in order to clarify how it occurs. We also examined possible paper-related factors in this problem. We found that ink peeling can be reproduced by creating four colors on the overlaid portion with a sheet-fed press, and then on top of this printed material, piling up a sheet of transferring paper together with a weight, which is rotated slowly, rubbing the printed surface. We found that at the stage when a solvent component of the ink penetrates into the paper and the ink tack becomes high, if the printed surface is rubbed applying a certain weight, the ink layer peels off at the interface with the coated layer. We observed the time for the ink peeling to occur is short, and the volume of fine pores of the coated layer is large. We hypothesize that the main causes of this problem are the hardening of ink and force of the rub. Furthermore, the ink, paper, dampening, conditioning, oscillation during moving printed materials, spray powder and other factors may contribute to this problem. Therefore, possible countermeasures involve controlling these factors.