It's a Bird, It's a Plane...It's Super UV/EB

Each year, more and more package printers are turning to UV and EB curing for their super drying and time-saving powers.

TODAY'S ULTRAVIOLET (UV) and electron beam (EB) curing equipment can't fly like Superman, but with their many other super powers, they don't need to, to impress end users.

For the past several years, package printers have raved about the high-productivity capabilities, easy maintenance, and low environmental impact of these drying systems, putting UV and EB curing equipment in high-demand. "I get about three or four calls a week from printers wanting to get into UV curing—they want the gloss," said Dave Douglas, vice president, business development of Printing Research, Inc. (PRI, Dallas, Texas). "It's usually the guys that have a five- or six-color press with coating capabilities, and they're ready to make the jump to get the edge on their competition."

When UV and EB curing was first conceived in the late 1960s, its popularity suffered from many myths concerning its safety and environmental soundness. However, with education about the drying processes, those concerns and others were dispelled.

Today, with growing support, UV and EB curing equipment suppliers are concentrating on developing affordable and compact dryers for smaller converters.

Small footprints to fill

Small to mid-sized printers are looking for a way into energy curing. They're attracted by the high productivity levels and increased revenue that the technology offers. But up until now, size of the equipment—let alone its cost, as in the case of EB—was prohibitive. Today, however, UV and EB suppliers are targeting the "little guys" of package printing with great success.

Prime UV Systems' (Carol Stream, Ill.) MiniScan 3C UV dryer is small, with a compact housing measuring 3.75˝ x 7.5˝. The dryer is also powerful, with Prime UV's Cool Cure technology providing intense, effective low-heat cure.

The technology completely cures UV inks, overprint varnishes, and pressure-sensitive and laminating adhesives, and installs easily on label and narrow- to mid-web flexo, offset, gravure, and rotary screen presses.

"It's taken off really well," said Elinor Midlik, president of Prime UV. "The compact 3C UV dryer delivers more energy and matches the highest speed of any printing press. It continues to be popular with flexo printers—its use in flexo is growing at a much greater rate than in any other printing method."

On the EB side, Energy Sciences Inc. (ESI, Iselin, N.J.) has dedicated a lot of R&D dollars to EB technology. The result: the EZ Cure, one of the smallest and least expensive EB machines on the market. While the machine is tiny compared to the house-sized EB technology of the past, Ed Maguire, ESI vice president/general manager, expects EZ Cure to get even smaller and less expensive.

One of three models, EZ Cure I boasts the fastest speed capability at 1,200 fpm, as well as the maximum cure thickness up to 1.2 mils. All three models are designed to be retrofitted on flexo and gravure printing presses.

"It used to be that you had to kick down the walls, put on a new roof and an addition if you wanted to retrofit with EB technology," Maguire said. "But now, I'd say that about 70 percent of the EZ Cures sold are retrofitted."

One catch with EB is its price, but that's improving. In 1990, the average EB technology cost about $1 million. But now, 12 years later, a converter can buy EB equipment for about $230,000.

Still, Maguire foresees that price decreasing further as people realize the powers of EB—such as its ability to immediately dry inks, coatings, and adhesives—and as a supply chain develops with increased demand, he said.

Little changes make a big impact

Very few monumental changes have occurred in UV and EB curing technology from year to year, but suppliers constantly work at improving their innovations. Operator friendliness is one of many areas in which UV vendors have tweaked their machines.

Operators now have more control over a UV curing system than ever before thanks to such additions as touch-screen remotes, and easy, menu-driven programs, said Mark Hahn, VP of sales and marketing at AAA Press International (Arlington Heights, Ill.). Operators can now adjust the UV auto-intensity settings proportional to press speed directly through the Touch-screen Remote. This allows lower web temperatures while fully curing the coating at slower press speeds, Hahn added.

In addition, features like automatic fault protection, automatic troubleshooting, and Ethernet modem support capability "make the UV system transparent in the operation, while decreasing waste, improving process control, and increasing uptime," Hahn said.

A part of AAA Press' LIGHTouch UV curing system that has undergone improvement is ease of accessibility and maintenance. Currently, Hahn said, AAA Press will add a new "Slim-Line" lamp cassette to its product portfolio, proven to increase intensity and reduce heat at the web. This new system can be combined with the company's IR dryer for a fully integrated, compact all-in-one curing/drying package. Like original LIGHTouch Cassettes, the new compact 3˝ x 5˝ cassette will enable operators to leave the web box behind to change a UV bulb. The new SQC Bulb feature includes cassette-in-cassette technology allowing operators to "change bulbs in seconds rather than minutes," Hahn said.

Glowing lamp lights

New technology is evolving in UV lamps and is proving worthy of its R&D dollars. One such technology is the electrodeless, or microwave-powered, lamp. "We have known that light reacts with certain chemicals that contain photoinitiators in predictable ways to produce cross linking and curing," said David Harbourne, president of Fusion UV (Gaithersburg, Md.), a company which makes microwave-powered UV lamps. "Fusion UV increased the application of UV in manufacturing by discovering and then patenting the use of microwave energy to excite the gases in our electrodeless bulbs."

There are many advantages to electrodeless lamps. They are a low-heat option for printers using heat-sensitive substrates, and the lamps provide stable and consistent UV output. "The UV output from a Fusion bulb remains stable for up to 8,000 hours," Harbourne said. "Typically, [it's] only 1,500 to 2,000 hours with electrode technology."

A brand new type of lamp emerging for curing UV inks and coatings is light-emitting diodes (LED). The benefits of LEDs include low-energy requirements and low-heat emission.

Despite these advantages, however, package-printing insiders remain divided on the future of the technology, said David Snyder, director of EIT Instrument Markets (Sterling, Va.). "Of much interest is the development of UV LEDs for UV curing. LEDs are increasing in power output and becoming available in different wavelengths, such as 365 nm and 390-395 nm," Snyder said. But, he added, "It is to be seen if LEDs will successfully replace conventional UV curing for some applications, yet to be defined."

Keep it cool

In the last few years, there's been a lot of attention and improvements made to curing systems to help reduce the heat generated by UV lamps. With the use of synthetic substrates becoming more popular, keeping heat to a minimum has become especially important.

PRI manufactures the COLD™ UV Curing System, which incorporates a filtered water tube that removes as much as 85 percent of the infrared heat radiated by the UV lamps, Douglas said. This allows the UV light to pass through and cure UV inks, varnishes, and coatings while maintaining minimal heat to the substrate.

The COLD™ UV Curing System provides all the benefits of a regular UV curing system, including instant curing for immediate in-line finishing; high-gloss, and scuff- and rub-resistant inks and coatings; and the elimination of air contaminants.

But by decreasing the amount of heat that reaches the web, the COLD system does more than protect substrates. "It actually adds life to the press and protects the operator," Douglas said.

Prime UV also produces a UV curing system designed to reduce heat on the web, while running flexible packaging materials and heat-sensitive substrates. The FLEXfilm UV processor features an open base UV lamp facing a water-cooled chill roll. Designed for easy installation on all types of flexo presses, the new FLEXfilm can be installed interstation on in-line web presses, or after the coating station on a CI flexo press.

The system ensures the complete cure of heavy coverage UV inks and guarantees the web remains at ambient temperature. Very compact, the FLEXfilm fits easily in between color units on all CI flexo presses, and can be installed as a retrofit on all CI web presses running flexible films. In addition, the processor is available in power levels from 200 to 600 watts per inch.

by Kate Sharon, Associate Editor