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.

Added Gardino: “There is a different ink formulation for LED lamps. But manufacturers of the inks carefully work with lamp manufacturers to make sure the inks properly cure. When the lamps changed, the ink had to change to optimize the results.”

The ability to print on thin materials as a result of UV-LED’s cool operation is perhaps the technology’s greatest benefit. “It allows [providers] to print on heat-sensitive materials,” he said. “In point-of-purchase displays, this allows them to use thinner, lighter weight foam board materials with better results. In retail specialty advertising, they don’t have to be as aware of the material.”

For his part, Mitchell believes the issue is not so much opening new markets. Instead, he said, UV-LED provides an alternative production method that may offer economic, environmental, or productivity benefits.

Considering these advantages provided by UV-LED, and even factoring in the technology’s disadvantages, a logical question arises. Why wasn’t the technology embraced earlier?

The reason is that the general evolution of digital UV curable printing technology is progressing incrementally to ensure quality and dependability, Gardino believes.

“LED was around half a dozen years ago, but...all the major players went into the hot systems due to the known dependability they offered,” he added. “The technology developed a little at a time...Now, we not only have the CMYK color gamut, but we also have a white and clear ink. And we’re going to have a primer, so in the case of a metal or a glass that needs a primer, printers can put that primer down and later apply the ink and clear coat.

“We’re going into the workflow and trying to automate as much as possible. We’re just trying to mimic and improve upon what’s been done in traditional screen printing and PAD printing.”


Other Considerations

According to Jack Skidmore, director of sales for Atlanta-based CET Color, a manufacturer of vacuum table flatbed and hybrid roll-to-roll UV printers, shops should weigh all factors before choosing UV-LED printing. The LED lamps provide benefits, he said, but they aren’t for every print operation.

“They are only suited to low-volume, low-production machines due to the lack of curing energy that they provide,” he said. “Currently you will only find them on printers that are using smaller, Epson-based print heads.”

Skidmore asserts UV-LED curing lamps tend to be found on lower cost printers, which open up print technology to smaller print companies that can only afford less costly machines. “A guy looking at a hot-lamp printer will, these days, always investigate the UV-LED, because it’s more affordable,” he said.

“But he will also find that the lower print speed of the UV-LED technology makes it very difficult to produce any volume, and thus have any sort of reasonable amount of return on investment.”

How quickly and completely UV-LED is accepted will depend on a number of variable factors, Gardino said. “One will be print heads. Will they be developed to provide finer and faster printing? At some point the industry will introduce metallic inks for UV-LED. We already have solvent metallic inks, so it’s probably just a matter of time until the industry develops new UV-LED metallic ink.”


Invest Now or Wait?

Now we come to the question of whether print service providers would be wise to invest in UV-LED now, or wait for the next generation to come along.

In answering, Mitchell carefully weighed the downsides of the technology, but gives a thumbs up. “The limitation of UV-LED today is printing speed, as LED curing systems tend to be slower compared to mercury halide UV curing technology,” he said. “UV-LED inks are also more costly than traditional UV inks due to the type and amount of photoinitiators. PSPs should consider investing in this new technology now, particularly if replacing a solvent press.”

As for Gardino, he said shop owners and managers need to keep in mind the opportunities that may be lost if they are not using the new technology to print economically with low power consumption UV-LED printers on heat-sensitive material. “I don’t think there will be a significant drop in prices on these machines, because when you introduce new technology, prices do tend to hang in there for a while. Especially if you’re one of few doing it.”

As for Skidmore, he observed that there’s a right printer for every shop. “Knowing what their needs are today, and what their expectations are for tomorrow will allow shops to align with the right printer,” he said. “We’re never going to tell someone to wait because we can guarantee the technology will be better next year, and the next and the next. The issue is can they achieve a decent enough return on the printer bought today to make the profit expectation they’re trying to reach? Within three years, they should make enough to pay for that printer at least 10 times over, then push it into a corner and upgrade to the most modern technology offered three years from now.”

Look at the big picture, he urged. “It’s really not about buying a printer, but investing in a device that creates a profit within your business model.”