INFLUENCE OF AGING PROCESS ON UV INKJET BLACK PRINTED PVC FOIL
During the lifespan, graphic products are exposed to various external factors. During their use, their properties(physical, mechanical, visual, etc.) change to a greater or lesser extent. It is necessary to observe/monitor changesand influence of external factors on their properties as soon as the product is created. The aim of this research is toexamine the impact of the aging process on the quality of inkjet printing. A different number of layers of black ink (in10 % tonal value (TV) and 100 % TV) and a different number of varnish layers were printed on PVC foil material. The samples were exposed to xenon light (λ > 300 nm) to accelerate the ageing process over a period of 72 and 216 h. They were measured by Datacolor spectrophotometer. As expected, with longer exposure time, greater changes occurred. According to the CIE ΔE*00 formula, the differences ranged from an imperceptible to a large colour change. After 72 h, the biggest changes in colour occurred in the K10 % with one ink layer and three layers of varnish. The smallest changes were in K100 % with one ink layer and no varnish. After 216 h, the greatest changes were observed in the K10 % sample with three layers of ink and two layers of varnish. The smallest differences were K10 % sample with one ink layer and without varnish.