The UV inkjet printing industry has undergone a revolution with the launch of UV-LED lamps. These lamps are designed to provide functional lives that are 10 times longer than UV lamps. They last up to 10,000 hours, and thus offer much lower operational and maintenance costs than their UV counterparts.
The longer life of the UV-LED lamps is but one of myriad factors that must be considered by print service providers contemplating whether to invest in UV or UV-LED technology. That determination will ultimately rest on such issues as the size of the shop, the volume of print, the types of substrates being used, and the owner or manager’s commitment to the environment, among others. In the pages ahead, we look at the differences between UV and UV-LED, why those differences matter, and what factors must be weighed in buying decisions.
Differences Between UV and UV LED
In addition to the long life of UV-LED lamps, UV-LED is different from UV in a number of important ways, reports Steven Tu, product manager for Ivine, CA’s Roland DGA Corporation. “They also emit very little heat, which makes them more versatile with respect to the media they support than conventional UV curing systems,” he says. “Consider also that UV-LED lamps do not need any warm-up time, so they are ready to start printing immediately after being powered on. They are also smaller, more energy efficient, and completely ozone free, making them a safe alternative to conventional UV lamps.”
Many UV-LED printers, including Roland VersaUV printers and printer/ cutters, support a broad array of substrates, including everything from PVC, leather, paper and board stocks, to foils, BOPP, PE, and PET film, Tu says.
When it comes to specialty applications, his company’s most compact UV-LED printers print directly on three-dimensional objects, such as smart phone cases, industrial and consumer products, promotional items and even iPads.
“The ability to print on such a wide range of surfaces allows you to branch out into new markets, from package prototyping and labels to signage, interior décor, personalization and specialty graphics,” Tu reports.
Jeffrey Nelson, business development manager for inkjet solutions with Fujifilm North America Corporation Graphic Systems Division in Hanover Park, IL, says the difference between the two technologies is obvious and comes down to how the ink is cured. “UV-LED uses a low-energy light source, and the lamps are expected to last the life of the press,” he says.
“And because it’s low energy, it is low heat, so it works really well for thinner substrates, which can be very volatile.”
On the other side of the equation, with UV technology the ink is UV cured, rather than LED cured, he says. The chief benefit is speed; the equipment can run much faster using conventional halide lamps. Fujifilm’s Onset S50, for instance, can produce more than 150 5x10-foot boards hourly. “It would be difficult to achieve speeds like that with a UV LED today,” Nelson says.
Another difference shows up in cost. The cost of lamps is lower in UV than in UV-LED, he adds. As that cost differential drops, UV-LED will continue to make inroads in faster presses, even in industrial applications. A final contrast between the two technologies is that UV-LED is a greener solution, due to not requiring as many bulbs to be replaced and lower energy usage, Nelson says.
According to Jim Cain, director of sales digital with Polytype America Corporation in Mahwah, NJ, which limits production to UV machines at present, the big difference is the curing power, as well as the light spectrum given off by the machine. UV machines have broader curing power, he says.
The traditional UV bulb has a broader light spectrum, while UV-LED has a tight and more controlled spectrum. “What that means is more curing power out of the traditional UV, rather than the UV-LED,” he adds. “The UV-LED is almost like a straight line, a more confined space, as opposed to the traditional UV lamp, which has a broader and deeper curing power.”