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UV cures all

Jun 1, 2003 12:00 AM

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UV printing has been one of the only areas of growth in an otherwise depressed industry. Perhaps that's because printers need not dive wholly into it: Hybrid and UV coating can provide the vibrancy and shine of full UV without the cost of a complete set of interstation lamps. Or maybe it's UV's ability to show-up conventional sheetfed when printing on plastic or uncoated stocks.

We spoke to four companies that have implemented UV technologies to meet customer needs, improve print quality, handle heat-sensitive substrates and turn a dusty sheet of paperboard into a glossy, attractive display. Their applications — and UV installations — prove that the technology is not simply all shine and no substance.

Flexible hybrid

Like a lot of printers, Suttle-Straus (Waunakee, WI) adopted UV by customer demand. A publisher client required its covers be UV-coated; for a while, Suttle-Straus performed this task offline, but not only was it a lot of work, it also increased the job's turnaround. The purchase of a new Mitsubishi 3F 16000 fullsize press allowed the printer to make an investment in UV.

Because Suttle-Straus had a mix of products and clients, however, it didn't want to dive into full sheetfed UV (the printer has a Didde halfweb dedicated to UV). “We need the convertibility of the press because a lot of our customers don't like UV, and wouldn't pay for it,” explains Mike Abbeduto, vice president of manufacturing. As such, the printer installed a UV curing system incorporating CoCure hybrid-UV coating technology from Grafix LLC (Burr Ridge, IL). The curing system consists of a double lamp after the coating unit, a lamp after the sixth printing unit, a docking station at units one and five, and a lamp that is rotated between units one and five, depending upon the job.

Suttle-Straus also has a fullsize Mitsubishi six-color with aqueous coater, fullsize Heidelberg two-color, a halfsize Shinohara with coater, and a small-format Heidelberg and A.B. Dick two- and one-color, respectively.

Many of Suttle-Straus' high-end customers like hybrid-printed jobs because of the coatings available. Abbeduto notes the printer uses UV coatings — from dull to gloss to a dull and gloss combination — to create some unique end products. One example the exec cites is a poster created on behalf of Harley-Davidson for its 100th anniversary. The poster features the motorcycle manufacturer's latest bike, with a depiction of every Harley engine ever created on the bottom. The combination of metallics over four-color process with a high-gloss UV coating highlighted another capability Suttle-Straus enjoys.

“One of the nice features is being able to run metallics inline and trap on them,” Abbeduto says. Before installing the Grafix system, Suttle-Straus press operators printed metallics and process in separate passes or inline while the inks were still wet, which ultimately compromised print quality. “But because we have a UV lamp after the first printing unit, we're able to put the metallic color in the first printing unit and dry trap as if it were a second pass, and it looks phenomenal,” Abbeduto observes.

Abbeduto says that changeover between jobs only requires changing the inks and slipping the UV cassettes out after the coating unit. The hybrid process is so efficient that Suttle-Straus often uses it to print jobs that aren't necessarily high-end, simply to speed production. “If we have a lot of heavy ink coverage on uncoated stock printed on conventional sheetfed, it would take 24 to 48 hrs. to dry,” he explains. “If we choose hybrid, it's dry off the press and looks much nicer.” The printer uses Sun Chemical Hy-Bryte hybrid inks, which Abbeduto notes have excellent holdout, compared to conventional inks.

Suttle-Straus' goal is to run only CoCure jobs on the Mitsubishi; currently, the press runs hybrid 40 percent of the time during three shifts. Once this threshold is reached, the printer envisions possibly adding UV capability to one of its other sheetfed presses.

Reliable UV

Fifty-two-year-old Anderson Lithograph (Los Angeles) has been around the UV block a few times. The 425-employee sheetfed and heatset-web printer first installed UV equipment from IST Metz GmbH (NĂ¼rtingen, Germany) on its older Komori sheetfed presses in the early 1990s with much success. Several years later, Anderson bought two new Heidelbergs and again decided to invest in UV: This time, however, concerned about the availability of U.S. service and support from IST, which was undergoing internal changes, the printer went with a different vendor.

The new UV equipment reportedly did not perform reliably. In July 2001, as Anderson prepared to invest in another press — this time, a fullsize Heidelberg 10-color with extended delivery and coater — the printer took another look at IST. The UV vendor had partnered with technotrans america, Inc. (Corona, CA), whose Sheetfed Div. would now provide sales, service and support to IST customers in the U.S.

Both the 10-color press and a recently purchased eight-color model have IST RDT interdeck lamps between each unit, as well as interpress UV lamps. Anderson decided to upgrade the lamps with higher-intensity bulbs, “which means we don't have to run the lamps at full power to cure inks,” explains Ed Binder, vice president of operations. “We can run them at 50 percent to 60 percent of power, which in turn gives us greater control over our UV curing.” The higher-watt bulbs also enable Anderson press operators to run UV-coated jobs on the Heidelbergs at higher speeds.

Anderson prints UV on substrates ranging from 17-lb. UV translucent stock, glossy coated cover stock and 24-pt. board to polystyrene, vinyl and static-clings. This is also where the IST lamps' lower energy usage benefits the printer. “Because we run our wattages down, we keep our temperatures to a minimum,” Binder notes. He cites the IST equipment's cooling capabilities for keeping lamps, reflectors and the plastic substrate cool. “That's key in UV printing, especially when you start running plastics — you don't [want the plastic to] get too hot, distort, and have stretch and fit problems.”

Applications include high-end catalogs, fashion-industry publications, ceramic-tile brochures that illustrate tile gloss levels, and automotive brochures with UV-coated photos. The printer also UV prints on uncoated stocks, curing at every unit via the interdecks. “It gives us superior ink holdout when running a very high-density ink-film thickness,” Binder says. “You don't get the typical dot gain as when you print on uncoated stock with conventional inks.”

And despite Anderson's earlier brush with reliability problems, the printer has no qualms about making a full dedication to UV. “We've thought about hybrid,” Binder admits. “But we already have the interdecks in every unit, and the hybrid inks are no less expensive than the UV inks.” Not even hybrid's major benefit — easy wash-up and conversion from UV to conventional — is a selling point for Anderson. The printer claims its changeovers aren't arduous; it also hopes to commit its new eight-color Heidelberg to UV permanently.

Plastic perfect

The Buhl Press (Berkeley, IL) specializes in high-quality color lithography — exclusively on plastic. Founded in 1955, Buhl has been printing with UV since 1989; the company has upgraded or added new UV equipment in 1993, 1999, 2000, and most recently, in 2001. President Charles Barkley observes that in those 14 years, UV has become a more reliable and manageable process for the nearly 100-employee printer.

The printer uses Nordson UV Inc.'s (Amherst, OH) QuadCure interdeck UV lamps with an inline UV tower coater on its two Heidelberg CD 102 six-color presses and Komori Lithrone L-640; its four-color Lithrone L-440 has only interstation curing. With such an extensive UV installation, it seems as if printing on plastic and UV go hand in hand. Not necessarily so, says Barkley.

“UV is not a panacea for plastic printing,” the exec claims. Buhl Press prints on a large range of plastics. “If there's a plastic out there, we've printed on it,” states Barkley. These include polycarbonate, high-density polyethylene, polyester, PVC, polystyrene, Tyvek and acetate. With both UV and conventional ink on rigid and semi rigid plastics, for such applications as floor graphics, shelf wobblers, transparent lighted signs, counter mats and static clings. The exec explains that while UV enables almost instantaneous curing — a major plus with nonabsorbing substrates — the UV lamps do generate heat.

Barkley adds the issue isn't how much heat is generated, but rather how the UV system dissipates the heat. “In my opinion, Nordson UV systems manage the heat as effectively as, if not better than, any of the competitive technologies in the marketplace,” he observes. “Their products are engineered more thoughtfully… They have some proprietary technology for heat dissapation and management that is beneficial when you're operating UV curing systems.” The lamps feature a four-segment reflector design that reportedly directs UV light around the lamp body, increasing UV output without increasing heat; at the same time, a dichroic coating on the reflectors absorbs infrared light.

Buhl Press prints on substrates ranging from 0.004 inch to 0.04 inch thick; the printer's most challenging applications are at both of these extremes. The thinner the plastic, the more sensitive it is to distortion — UV heat can simply add to the problem. The thicker the plastic, the more difficult it is to handle. “Due to the mass of plastic relative to paper, thick substrates tend to be tough on a press simply because they are so heavy — sometimes we print material that weighs more than two pounds a sheet,” Barkley notes.

The UV systems' ability to manage heat certainly aids Buhl in mastering these applications. Ultimately, however, it is the printer's own highly developed skills in printing on heat-sensitive substrates that translates into successful jobs. “We approach the most challenging applications with great care and more than 45 years' experience with plastic printing under our belt!” Barkley exclaims.

Dedicated to coating

Tim-Bar POP (New Oxford, PA) specializes in point-of-purchase (POP) displays, from design to creation. The 185-employee division recently changed its name from Corrlam Packaging, after it and Oxford Innovations, a display manufacturer, were combined into the Tim-Bar POP & Display Group.

In January 2001, Tim-Bar POP purchased a used 64-inch KBA Planeta — but not for printing. Instead, the company wanted to create an offline UV coater for its POP projects. “Basically it was driven by our customers — they were looking for a more reflective, higher-gloss image, as well as additional protection for packaging and displays,” explains Rob Miller, plant manager. Tim-Bar decided to go with an offline solution because the volume of work for the coater was too modest to justify an inline curing system.

The Planeta was shortened to two stations — one acts as a UV coater, while the other doesn't have rollers but could be converted to print one color. Attached to the back of the press is the transfer station with UV lamps to perform the curing and to run any of Tim-Bar's offset jobs that need UV coating. Tim-Bar POP has two other 64-inch Planetas — one six-color, the other seven-color plus coater — that handle the offset printing side of jobs. “We normally print the sheet and apply an aqueous base coating, which is attractive to the UV coating, and then we run it through the UV coating press,” Miller notes.

The UV-coating retrofit package, developed by Prime UV Systems (Carol Stream, IL), features three double-cool UV lamps to increase the curing speed while minimizing heat on the substrate. It also has a Prime Smart 2100 Control Platform, from which the operator can monitor curing parameters and increase the UV intensity as the speed of the press increases. The control platform also has a dedicated computer system with an I-modem, which links the printer's operations to Prime UV's service department.

Tim-Bar POP prints primarily 10- and 12-pt. board; after the stock is printed and UV-coated, it is laminated to fluted material, converted and diecut to become packaging or displays.

Miller concedes that as Tim-Bar had no prior UV experience, startup was challenging; a couple years later, he reports the company is becoming “quite successful” at UV coating. This has taken some trial-and-error. Tim-Bar operators need to correlate the cure time and lamp intensity to the curing requirements of the coating. “We had to go through some experimentation to avoid under- or over-curing,” Miller notes.

Although Tim-Bar prefers to print on clean and smooth paperboard, it does have to deal with recycled stocks, which tend to be dustier and can cause problems in the printing and coating processes. To counter this, the company installed a new dampening system on its seven-color Planeta. This helps control dirt and prevent hickeys from forming on the printing plate. “During UV coating, we'll put a blanket on that first station to help pull dirt off the sheet before we put on the coating, which helps control dirt as well,” Miller says.

For now, Tim-Bar has no plans to expand into inline UV — that, Miller notes, will ultimately be determined by volume and demand.

What's new in sheetfed UV curing

Following are some of the latest innovations from vendors of UV curing systems for the sheetfed market. As a side note, Baldwin Technology Co. (Shelton, CT) ceased selling UV systems to the sheetfed market earlier this year.

Eltosch North America Inc.'s (Brookfield, WI) offerings include Everclear UV lamps, which use an optimized circular halogen process to avoid the phenomenon of “edge blackening.” Contamination of the UV lamp by electrode material is also reportedly delayed, enabling the lamps to operate up to 4,000 hrs. if properly maintained. Eltosch also provides hybrid curing systems, online UV measurement and control systems, integrated cold-air UV systems and inert-UV technology.

Eltosch has been supplying inert UV systems since 1992, primarily for the specialty printing market, but has begun offering the systems for sheetfed printers. Inert UV is said to provide efficient curing of UV ink, savings in photoinitiator, reduced UV-energy requirements by up to 75 percent, and perhaps most importantly, lower-temperature curing on heat-sensitive substrates. Eltosch's first sheetfed inert-UV installation in the U.S. is at Ivy-Hill Packaging (Louisville, KY), where the technology has just been installed on a KBA Rapida. >>

Fuchs-DeVries, Inc. (Mundelein, IL), which is known for its exhaust systems and hot-airknife and infrared drying systems, also offers interstation and UV drying packages. The company plans to introduce a coating conditioning system for aqueous and UV coatings this year. >>

Grafix LLC (Burr Ridge, IL) has established itself in hybrid UV with its CoCure inline UV coating technology, which enables printers to UV-coat jobs inline without dedicating a press to UV exclusively. Its C1, C2 and C3 UV dryers are equipped with quartz-glass lamps and dichroic reflectors for high UV yield and low infrared radiation. When production is disrupted, the dryer goes into standby mode, its shutter closes and the lamp turns its power down to 40 percent. The unit is air- and water-cooled for even heat dissipation. Other features include centrally controlled lamp operating status, ventilation temperature and shutter position.

Vice president of technical sales Vince Kowalski says that at Drupa 2004, Grafix plans to debut a design change to its UV drying unit that will increase its water-cooling capabilities by about 90 percent. >> (866) 472-3498

IST Metz GmbH's (NĂ¼rtingen, Germany) RDT (Reduced Down Time) UV interdeck curing unit features a patented-power-control system that reduces the UV lamp's power to less than 20 percent and maintains the lamp in standby mode when not in use. The system's newly designed airtight shutter system encloses the UV lamp during press stops, preventing solvent vapors from penetrating the housing during automatic wash-up. IST's sheetfed UV systems are distributed in the U.S. by technotrans america's Sheetfed Div. (Corona, CA). >>

Heidelberger Druckmaschinen AG (Heidelberg, Germany) recently announced that it can supply Speedmaster CD 102 users with CoolCure oxygen-reduced UV drying technology, which it codeveloped with IST. The inert-UV technology reduces the output of UV lamps, boosts the drying process' efficiency and transfers less heat to the substrate, making it ideal for UV printing on plastic films and aluminum-coated paper.

Nordson UV Inc.'s (Amherst, OH) QuadCure UV lamphead is said to provide high UV output with reduced heat-generating infrared energy. The lamphead's four-segment reflector design directs UV light around the lamp body, which reportedly increases UV output without increasing heat. A dichroic coating on the QuadCure's reflector further enhances heat management by absorbing infrared light. The fully shuttered system uses air and water-cooling technologies to control temperature; an integrated UV monitor built into the lamphead and quick-change bulbs are additional features. >>

Oxy-Dry Corp. (Itasca, IL) is introducing a new design option for its UV curing system at Graph Expo 2003. The new air-cooled, shutterless broadband UV system reportedly delivers up to 800 watts per inch per lamp, and is said to offer greater efficiencies and performance than existing systems while reducing the maintenance issues found in using older technology systems. Determined by the type of inks utilized, the Oxy-Dry system can be customized to fit individual applications, whether inline UV, hybrid or UV coating. Oxy-Dry also offers a DuoTek UV hybrid curing system for sheetfed printers mixing UV coatings with hybrid inks.>>

Prime UV Systems (Carol Stream, IL) recently announced a new sheetfed coating system that reportedly enables printers to inexpensively and easily apply and cure UV coatings in-house. The system includes a sheet feeder, UV sheetfed coater, sheet transport conveyor, Optimum air-cooled Prime UV lamp and sheet stacker. Press operators can apply UV coatings over water-, solvent-based or UV inks.

Prime UV has also introduced a UV conveyor system that installs inline to sheetfed presses. The small-format conveyor fits into the press' stacker area and transports sheets through the UV processing unit. >>