Simply More Gloss With UV

UV gloss – a subject that many people cannot ignore and neither do they want to. Technical progress has made it easier to achieve maximum gloss.

UV printing has enjoyed tremendous growth in recent years. It's hard to imagine how one could do without it for printing on plastics and metallized substrates and it's becoming more and more popular for folding box production as well. This is because packaging is no longer merely a protective container for products but has become an important sales and marketing instrument. Matt and gloss effects used together on packaging catch the consumer's eye, convey value and stimulate the urge to buy.

UV coating provides the highest gloss, and this gloss effect can be increased considerably by applying a matt coating to the surrounding areas for contrast. There are several methods for achieving UV gloss: the primer-UV process with a double-coater press whereby primer coating is applied in the first coating module and UV coating in the second; the hybrid UV process which only needs one coating module; and the pure UV process where UV coating is applied over UV inks.

Technically demanding

Combi operation is the most exacting process, using two varying printing ink systems that have different chemistry and behave much differently as well. It is precisely these differences that have led in the past to long makeready times when changing from one system to the other. The different printing behavior and less damping latitude of many UV inks is hard for many users to get used to and requires considerable skill and experience. This is why MAN Roland is constantly researching to find engineering solutions to simplify the changeover process, speed it up, and enlarge the process window at the same time.

Washing and cleaning as a productivity factor

One example is the development of new washing and cleaning systems. Washing of rollers and blankets affects process stability and economy in UV printing, especially with alternating operation. Incompatible washing agents and residual ink can lead to an increased number of waste sheets. MAN Roland conducted a series of tests and the most important finding was: no washing agent cleans better than the one specifically matched to the ink system concerned.

MAN Roland has developed QuickChange Wash which greatly reduces operator contact with washing agent during set-up and changeover. This new development offers automated alternating operation with separate supply lines for the different washing agents with alternating activation.

Complete separation of the individual supply lines reduces makeready time and increases operating comfort. No lines need to be emptied and re-filled. No washing agent is lost which is often the case with alternating operation. The biggest advantage is the outstanding washing quality with the specific washing agent for the inks used. Washing times are shorter and the process is more efficient because there is no longer any mixing of washing agents that are not fully compatible. Meanwhile MAN Roland also offers separate washing agent circuits for cloth-type washing units.

Expert advice

Developments in UV technology are ongoing and MAN Roland is intensively involved – whether this be new processes for stabilizing emulsification in printing or new UV curing equipment for heat-reduced hardening with sensitive substrates. The high level of innovation leads to continual reappraisal of knowledge and also more intensive communication with customers and users. Here MAN Roland is pleased to offer expert advice – interested parties can send their process-technical questions to the central e-mail address UV@man-roland.de