| Popis: |
Printed packaging surely is the most perspective field of graphic technology. Packaging is the crucial part of the good placement of products on the market, while constant competition increment makes it even more important. Even though paper is the uppermost material used for packaging production, there are some products (meat products, beverages, fluids…) that demand materials of greater resistance and firmness, like metals. Traditionally, metal packaging is printed in offset printing technique, but digital Inkjet techniques that use UV curing systems also have the possibility to print on any material, accordingly also metals. This enables personalization of metal packaging, short runs and more relevant proof sheet printing. The possibility of Inkjet printing on the steel tin plates (that are normally used for offset printing) will be analyzed in this paper. The aim of the experiment is to determine the successfulness of color printing in Inkjet printing technique onto metals and the possible usage of it for the proof sheets printing. The efficacy of the reproduction of UV LED Inkjet inks on the metal substrate will also be determined. To define every relevant printing parameter (gamut, CIE L*a*b* values, ΔE, ΔL, ΔC, ΔH) and quality of reproduction of the smallest screen dots, colorimetric and imaging analysis were applied. For the printing of samples on the metal and paper substrate, Roland VersaUV LEC-300 machine was used, applying ECO-UV CMYK colors and UV curing system. Measurements were done by spectrophotometer and colorimeter X-Rite DTP20 Pulse. Results have shown there is a possibility of printing on metal substrates using Inkjet. Average color differences of CMYK patches, between metal and paper substrate, suggest that cyan (ΔEC ; metal-paper, avg.=4, 50) and black (ΔEK ; metal- paper, avg.=4, 63) give the best reproductions. Magenta and yellow show somewhat higher color differences between metal and paper substrate, which is caused by the lower lightness of the metal substrate itself (ΔEM ; metal-paper, avg.=6, 57 ; ΔEM ; metal-paper, avg.=5, 61). Reproductions of dark hues and solid colors are especially good. Light hues and low halftone values should be avoided or corresponding corrections should be made before printing. |
