The ABCs of UV-LED (or) The EZ Approach to UV- LED

It’s no secret UV digital is the fastest-growing segment in the wide-format printing industry. As it has evolved, it’s assumed a central place in the graphics business. Now, UV-LED, the latest generation of the technology, is moving rapidly toward the forefront of the UV digital field. Savvy providers are realizing they need to know more about UV-LED and the opportunities it makes possible.

Terry Mitchell, director of marketing for the Graphics System Division of Fujifilm North America in Kansas City, said leading-edge shops should be aware UV-LED may offer an alternative to solvent and eco-solvent presses in creating banners, signs, and point-of-purchase displays. “UV-LED does not emit VOCs, has little or no odor, and offers low operating cost benefits,” he said. “Additionally, the low operating temperature of LED curing systems lets shops produce work with UV curing on heat-sensitive and thin materials.”

But there are disadvantages as well, the chief being that UV-LED printers are slower than existing mercury halide UV curing technology printers.

This month, WFI examines the difference between UV-LED and past UV digital technology, explains why the advent of UV-LED has necessitated the advent of new inks, and explores the markets UV-LED opens up to print service providers. Most importantly, we tackle a question providers are asking. Should they invest in the new technology, or wait for the next step in its evolution?

A Little UV LED History

UV-LED printers have been in the ascendancy for at least the last couple of years, said Fran Gardino, Boston-based business development manager with Mimaki USA. The first iteration of the technology emerged from Russia about four years ago, but never really seemed to catch on in the marketplace, he added.

Mimaki USA came out with its first UV-LED printer about three years ago. The UJV-160 is a hybrid UV-LED printer, featuring flatbed and roll-feed. With it, “you can print thin foam boards, the lightweight stuff, and roll feed media,” Gardino recalled.

Mimaki USA next introduced the JFX-1631, a true flatbed, and then unveiled a smaller true flatbed, the JFX-1615R, both with optional roll feed attachments. Another small UV-LED machine, the UJF-3042, is a 12x16-inch flatbed printer aimed at award, specialty, and industrial markets, which continues to sell well, he said.

Two important benefits of UV-LED printing have fueled its growth: cool operating temperatures and low energy usage. “UV-LED emits a different wavelength than mercury halide lamps,” Mitchell explained.

“The benefit in terms of UV ink curing is less heat generation...UV-LED lamps have a longer operating life than mercury halide lamps, with little to no UV output ‘drop off’ as they age, and they consume less electricity.

“This gives UV-LED a lower operating cost.”

Thinner Substrates

Heat emitted by UV lamps can adversely impact some substrates, such as thin materials susceptible to warping or distortion as a result of heat, Mitchell added. Thus, shops using UV-LED printers are now able to turn out work on thin materials that previously couldn’t be utilized with hot lamp UV printers.

Gardino agreed that the cool operation is an important advantage of UV-LED. “The good thing about the coolness is it doesn’t distort the media,” he said. “Some plastics, the thin PVC, will actually warp if you’re printing in high-quality mode, or even in non-high quality. Anything susceptible to heat will warp. So the benefits are low power consumption UV-LED printers’ energy savings and coolness.”

New Inks Required

With the change in lamps has come a change in the ink formulations used as well. Photoinitiators in UV-LED inks must be “tuned” to the UV wavelength of the LED lamps in order to cure the inks, Mitchell said.

“Typically, there is a higher concentration of photoinitiators as well,” he said.