This report introduces factors to improve image quality obtained by single pass inkjet printing with UV ink. As reported at NIP24, this study is made with 600 dpi single pass inkjet printheads, capable of single pass printing at 847 mm/s in 108 mm print swath. In the former study, authors concluded that image quality could be sharper by higher pass speed in case of single pass inkjet printing, since amount of ink flow on a media surface before curing can be restricted. However, it was revealed that fast printing speed could suffer image quality with unevenness of image surface created with thick ink layer. In order to solve the problem, approaches are made from both ink and printhead properties. Firstly, static surface tension of UV ink is lowered from 30 to 22-25 mN/m. It is expected to maintain enough dot gain with smaller drop volume, which makes ink layer thinner. Also, color density of ink has to be enhanced to keep equivalent color range with thinner layer. Secondly, printhead is modified in terms of optimum drop volume range from 5 – 19 to 4 – 12 pl for modified ink. Also, drop placement accuracy is improved by increasing drop velocity. As a result, thickness of ink layer is reduced from 12.7 microns to less than 9.6 microns on a gloss coat media. As a result, appearance of color images are much improved. It is achieved UV ink named AGORA G1 developed by Agfa Graphics.
Shin Ishikura, Takahashi Daisuke, Mori Kentaro, "Improvement of image quality in single pass UV inkjet printing" in Proc. IS&T Int'l Conf. on Digital Printing Technologies and Digital Fabrication (NIP26), 2010, pp 349 - 352, https://doi.org/10.2352/ISSN.2169-4451.2010.26.1.art00092_1