Ink selection for inkjet printing

　　Ink is a very critical component of inkjet printing. It not only determines the quality of the inkjet image, but also determines the shape of the ink droplets and the reliability of the printing system. Different label and packaging branch areas have very different requirements for the characteristics, functions and specifications of digital inks, but the same is true, and inks are required to have high reliability in terms of sprayability and adaptability.

　　Color inkjet digital printers typically use one of two inks, UV inks and water-based inks. Among them, the UV ink used in the UV inkjet printer is 100% solids, containing pigments, prepolymers and UV-sensitive materials. Once the ink is printed onto the substrate, the prepolymer hardens and forms a dry colored layer under the action of ultraviolet light. The hardened UV ink has excellent water resistance and fading resistance, and its chemistry is comparable to UV flexo printing. Using UV curing technology, the ejected ink droplets typically solidify into a hard, durable, impervious surface in seconds. UV inkjet is suitable for narrow web printing and direct molding on thicker materials such as labels.

　　The ink used in the water-based inkjet platform contains a colorant dispersed or dissolved in water. When printing, the substrate absorbs moisture and the dye or pigment remains on the substrate. Some industries use water-based ink technology later than expected, but in recent years, with the improvement of ink performance, the function of the nozzle and printing press, this ink technology is now gaining good momentum. Water-based inkjet is suitable for single-sheet large-format printing of flexible packaging, paper and paperboard. It is especially suitable for food packaging because it does not contain volatile organic solvents.