Coat, Cure All Over

News of expanded offerings and growing adoption of presses with integrated coating and curing have been unfolding at a torrid pace. Particularly hot are double-coating applications and, something new, two-sided coating.

At its annual global press conference December 7, Heidelberg announced it will offer its Speedmaster XL105 in two UV versions: one a UV press, another configured to run as a double-coater press with interstation curing. Both versions of the 18,000-sph 40´´ press will be available as standard from mid-2007.

Just days before, Minneapolis-based Bolger Vision Beyond Print announced it had installed the first-of-its-kind UV perfector press, a KBA Rapida 105 10-color that prints and coats both sides of the sheet, curing the first side before tumbling it, and eliminating the challenge of sheet marking.

In recent weeks, trade printer 4Over Inc., Glendale, CA, started up the first-ever Komori LS440SP Lithrone Super Perfector with dual-sided coating. Featuring the unique LS440SP staggered cylinders (top and bottom), 4Over's Lithrone prints and coats both sides without turning the sheet over. So quickly is this market moving that Carlsbad, CA-based Modern Postcards, just featured in November GAM, will soon be starting up another Komori with that same high-profile coating capability—the second U.S. installation of an LS440SP—by the end of this quarter.

UV printing with coating expands the range of substrates that can be run, opening new markets. Typifying this trend is Jackson Press, the Indianapolis printing division of marketing agency The Jackson Group, which added a 6-color-plus-coater MAN Roland 700 that applies UV-curable inks and coatings to print on vinyl, styrene and a gamut of plastic substrates. “We're going to apply that capability to produce products that require either durability or to print pieces that need a very high-gloss look to deliver the highest level of appeal to the consumer,” says Ron Jackson, president.

At the beginning of this month, Mitsubishi was set to bring two-sided coating to its tandem perfector Diamond 3000TP, offering the ability to apply aqueous or UV coatings to the front and reverse sides of a sheet in one pass. The 40´´ press, available with up to 12 printing units, prints both sides sequentially in one pass without turning the sheet. Now sheets will arrive in delivery dual-coated, cured and ready for finishing. Mitsubishi previously introduced two-sided printing and coating for its Diamond 3000R Double Diamond convertible perfector. The double-coater version features tower coaters before and after the Translink unit, a three-cylinder transfer system that passes back-side printed sheets to the front-side units without flipping them. That unit can be fitted with UV or infrared dryers.

The explosion in popularity of presses with coating and curing is reflected in the range of platform configurations that can be specified on new machines. But perhaps to an even greater extent, a wide selection of aftermarket peripherals can turn existing press lines into production tools capable of executing highly creative, multi-layered designs. Whether retrofit or ordered with new presses, the coating and curing capabilities provide the key to turning commodity print into value-laden specialty.

UV applications, the heart of the boom in coating and curing, are expected to grow 10% annually, according to a Print Outlook presentation by Roland Krapp, VP Sheetfed Product Management, Heidelberg USA. Sales of presses equipped for UV are growing 7%, peripherals 10%, and UV ink and coating supplies 14%. The trend reflects a move away from commodity 4-color, says Krapp, to luxury print.

In addition to applying conventional inks and aqueous coatings, these configurations and available drying packages provide great flexibility in the job mix, such as spot UV coatings, UV inks or hybrid-UV inks. Double coaters accommodate aqueous-over-aqueous coatings, UV and aqueous coatings on either side of printed sheets or UV-over-UV applications. When spot UV gloss coating is followed with aqueous matte flood coating, for example, the contrasting textures create eye-popping effects. Examples of these techniques were demonstrated by KBA on the Graphic Arts Monthly June 2005 cover; and by Sun Chemical on the August 2005 and September 2006 covers.

Special effects are emerging with branded identities. At Graph Expo, Heidelberg announced Saphira DripOff, a high-contrast matte/gloss coating effect that can be achieved in a single pass using conventional inks and a special oil-based matte varnish placed in the last inking unit. The glossy dispersion coating is repelled in all areas that previously received the matte coating. The coating “drips off” and is unable to form a glossy film in these areas. This different surface effect provides a contrast between matte and gloss that produces a whole range of optical effects, such as a mirror-like or silvery appearance. Ryobi/xpedx offers “Chemical Embossing” in which a flexo cylinder imparts a textured surface to the coating. Sun Chemical uses the term “reticulation coating” to refer to the interaction between spot and flood coatings that creates contrasting surfaces and gloss.

Of course, coating and curing is not just for the 40´´ presses. Plenty of 29´´ and smaller sheetfeds as well are incorporated with coating and curing capabilities, and webs, too, as printers serving numerous niches rush to add value to work, and rush work to delivery.

MAR Graphics, a direct mail printer in Valmeyer, IL (featured in GAM 11/05) expected to reduce makeready time 50% when it announced the addition of a highly automated 10-color Concepta web from Muller Martini to handle a diverse array of commercial and direct mail work. It has been configured with a turret rewinder for jumbo rolls, a high-speed sheeter and Prime UV 22´´ and 28´´ inserts that allow it to vary the coating capability as it varies the cutoff dimensions. The firm had been running Didde webs, but the new press is light years ahead of that aging technology, says Rick Roever, president of MAR Graphics.

“Our makeready time on the new Concepta press will be half or less than it is now on our other UV presses,” says Roever. “With CIP3, printing to color can be accomplished much faster as all press color settings are automatically set with their computerized servo motor-driven ink fountain.”

One of the premier developers of specialized applications for curing and coating systems on press is The Williamson Printing Cos., Dallas. The firm ordered four customized Heidelberg presses, a total of 51 printing units, during Drupa 2004. They included a Speedmaster XL 105 8-color with coating (used to produce the January 2006 GAM cover), two Speedmaster SM 102 12-colors with coating unit, and a Speedmaster CD 102 10-color machine with three coating units, three drying units and an extended delivery. The last of these lines was to be installed by June 2006. Williamson also develops its own inks for specialty projects.

Such presses supply high-quality advertising material with an impressive range of surface finishing techniques to its very demanding customers in the jewelry, fashion, automotive and home furnishings industries. Requests for customized machines is growing, says Heidelberg, which reported then that one in five Speedmaster 102 format presses had been customized. More than 16% of coating and drying units supplied by Heidelberg are destined for customized presses, mostly long perfectors, where Heidelberg claims global market share in excess of 70% (an installed base of over 900 presses in 2005). One of the two Speedmaster SM 102 12-colors for Williamson was outfitted for UV. The Speedmaster CD 102 Duo is a particularly interesting configuration because it combines flexo and offset.

The flurry of installation reports reflect both the raging demand for automated presses, but more particularly, the desire by printers to differentiate their output. They are doing so by fulfilling designer goals of more enchanting and sophisticated, “layered” designs combining UV inks, conventional inks and hybrid mixtures of the two. The results provide contrasting levels of glossy and matte reflectance, pebbly textures using special coatings with flexo coating chambers, and dimensional shading imparted by the coatings, laid over images to add depth and contour.

For Bolger Vision Beyond Print, the 220-employee, $30 million printer based in Minneapolis, adding uniqueness along with new capacity was paramount.

“It's critical to differentiate ourselves from the competition,“ says CEO Dik Bolger, who began researching at Drupa in April 2004. The five-over-five, 10-color Rapida 105 perfector, with coaters after the 5th and 10th units, is the first of its kind in North America. “It surely does differentiate us from our competition and it is surely pushing the technology envelope,” Bolger says. While the press can deliver designs that push creative limits, it is also practical. Why? Run with UV, the sheets are fully cured before they turn. “There's no marking,” says Bolger. “UV drying on both sides of the sheet eliminates these issues.”

Bolger's press will also run hybrid inks, which mix conventional and UV, to provide varying levels of gloss depending on substrate and application. “The UV curing gives us better trapping and no dot gain. Our printed sheets are dry in the delivery of the press and ready for the bindery.”

Komori describes its coating-enabled presses as “the ultimate specialization platform,” which allows printers to print on unusual substrates and expand into niche markets. The Lithrone S40 can be configured with the Komori Inline Coating System, designed with chamber and anilox roller technology—a popular configuration on many presses. (See related story on Zoom Graphics, p.34). The anilox design allows the press to lay down a heavier weight of coating, metering it to a predictable thickness. The Lithrone platform is customizable for specific UV applications, including double and even triple coaters.

One example is a 7-color Lithrone with two drying units that might be used to lay down two layers of UV white followed by four layers of UV process, with UV overprint or UV coating, permitting vibrant color on porous or off-white substrates. Materials handled include film, metallized paper and packaging.

Heidelberg says field tests of its newest XL105 UV and LYYL (L = coating unit, Y = drying unit) saw productivity in UV and double-coating rising up to 30% on stock ranges from 0.03 mm to 1 mm. The inking unit itself is kept at a consistent temperature and, in conjunction with the separate ink fountain roller temperature control, holds precise and stable ink metering.

A special feature of UV coating units are pressurized chambered doctor blade systems, which ensure more even coating results. Such presses are usually supplied with extension modules in the delivery—extended sheet travel provides sufficient dwell time for optimum gloss effects. The new DryStar 3000 UV dryer was designed for the Speedmaster XL 105 UV. The dryers are fully integrated into both the printing unit and delivery. The interdeck dryers can be moved freely from printing unit to printing unit without the need for tools, thus implementing “plug and print” and achieving maximum flexibility. As an alternative to a pure UV press, the Speedmaster XL 105-LYYL can process conventional inks and give them a UV coating inline once a primer has been applied. A range of combinations are possible such as primers with metallic coatings, Iriodin (pearlescence) or functional coatings.

In addition to the systems designed by or for press manufacturers, other sources also offer a range of coating and curing peripherals, including Air Motion Systems, Technotrans, Prime UV, Grafix, Nordson, PRI and Harris & Bruno, covered in recent reports in GAM.

Air Motion Systems, which operated a UV Lounge at the past two Graph Expos, says it saw a record year, with over 400 Peak UV units, its flagship system, now installed in North America. “Demand for our systems is greater than ever” says Hans Ulland, VP sales. New customers revealed at the show include Renaissance Mark, which recently broke a speed record for curing its Peak UV on a 40´´ Mitsubishi Diamond 3000; Shorewood Packaging on a Heidelberg Speedmaster CD102; Unimac Graphics and Trojan Litho on large format KBA Rapidas; National Posters and Lithographix on KBA super large 205s and Colonial Carton and Cedar Graphics on 40´´ Rapidas.

Dispensing with heat is an important factor in UV curing, especially in working with plastic substrates. Nordson, for example, says its QuadCure lamp head combines the high UV output needed for fast, thorough curing with specialized heat-reduction technology. Designed with the aid of computer-simulation software, its four-reflector geometry has been optimized for maximum UV output, directing UV light around the lamp body to increase output without increasing heating, in part through enhanced dichroic reflectors, which are fitted as standard. These absorb heat-generating infrared light, while reflecting UV. The reflectors are water cooled rather than air cooled to minimize contamination to substrates.

Printing Research, which makes a range of systems for IR and UV curing, offers the Cold UV curing system featuring chilled water to cool the lamp head and to filter out the majority of unwanted infrared heat, while allowing the UV energy to pass through and cure the UV inks and coatings. Single-lamp interdeck systems can be easily removed for placement in alternate docking stations. A multi-lamp configuration allows for curing at higher production speeds and end-of-press curing of hybrid inks.

Technotrans offers the alpha.v unit, a circulator supplying coating units with dispersion coatings or UV coatings, and which is compatible with chamber doctor blade systems or roller coaters. It also offers the zeta.v lacquer heating module for coating circulators connected to printing presses that do not possess an independent temperature regulating system.

Grafix, which has a wide range of coating curing systems, began producing UV dryers for jumbo-format sheetfeds in 2005. The company also offers hot air dryers (HAK), infrared dryers, combination dryers and controlling systems.

Inks and their interaction with coatings are key factors in the successful execution of complex coating and curing work, as are rollers and blankets. The complex chemical reactions generated by the interaction between conventional inks curing with infrared heat and UV or hybrid UV were tested by KBA at its sheetfed facility in Radebeul, Germany. Tests were designed to assess the performance of the hybrid inks in conjunction with inline coating and to investigate the levels of gloss attainable with subsequent UV varnishing for a variety of press configurations.

The print tests were carried out on a Rapida 105 with five printing units, followed by a coating tower, two intermediate drying towers, a second coating tower and an extended delivery. Complete results are posted at KBA's Website, but at an application of 320% without interdeck UV drying but with UV coating in the anilox coating tower and UV final drying in the delivery, a gloss of 85 points was achieved. With an application of 200% the gloss rating was increased still further to 89, which placed it above the gloss of the paper. There was still no measurable drop in gloss after 120 hours. The level of gloss, however, is also dependent on the production speed. Rub-resistance, on the other hand, is significantly higher than that of “normal” offset printing inks.

In a technical paper at its site, roller, blanket and wash supplier Böttcher notes that since the chemical composition of UV-cured printing inks is quite different from conventional mineral oil-based inks, roller covering compounds, blankets, washes and fountain solutions must be carefully selected. Incompatibility between inks, chemicals and rubber components can produce swelling or shrinking, altering the geometry of rollers and blankets, diminishing print quality and reducing roller service life. The selection of the right compound for damping roller coverings in UV printing also depends on the type of press in use.

An aggressive or incompatible wash, notes Böttcher, can cause premature destruction of rollers and printing blankets. Only washes adapted for compatibility with specific rollers and blankets prevent swelling and thus ensure trouble-free printing operations.

Sun Chemical, which says it pioneered energy-cured inks, notes the first commercial application of UV curing inks took place in 1969 on a sheetfed application. Along with its Rycoline and Kohl & Madden brands, Sun offers a wide range of chemistries, inks and additives capable of achieving many specialized effects with on-press coating and curing systems. The company's coating offerings include work-and-turn coatings in gloss, matte, semi-gloss and satin formulations, in a variety of rub resistance and levels and for one- or two-sided work; and web press formula Diamond Coat Extra High Gloss.

Among offerings from Kohl & Madden and Rycoline are K&M Cure UV curable inks, including varieties for waterless UV, forms and web work; K&M Brite hybrid chemistry that combines the conventional sheetfed ink press performance properties with UV-curable technology; Kohl & Madden and Rycoline Aqueous coatings designed for both aesthetics and product protection, formulated for rub and scuff resistance, high gloss, quick work and turn, and increased efficiency. Kohl & Madden says its Cure line features proprietary monomer technology for excellent ink-water balance characteristics and press stability to come up to color quickly on long and short runs.

Flint introduced Arrowlith UV coldset web inks at Print 05, for production of full-color, high-volume newspaper inserts, Sunday sections and other special in-house projects at newspapers, without requiring a lengthy heatset dryer installation.

Gans Ink's energy-curable inks, from its Utah division, include VinylCure, formulated with rheological properties to allow running with less fountain solution while still keeping screen values open and maintaining a sharp image. All VinylCure shades are fully charged with pigment for the formulation of shades that eliminate the possibility of bleed. VinylCure also resists delamination, even on full bleeds, says Gans. The firm's No-Lam ultraviolet-curable inks have been formulated for the sheetfed printing of plastic cards. No-Lam inks are engineered to be press-polished in the standard lamination step and do not require laminating or overprint coating. No-Lam is available in a 4-color process series, dense black and Pantone shades. Gans RapiCure UV-curable inks are formulated for sheetfed and web applications on paper and folding carton stocks. Gans offers OS UV-Hybrid process inks that combine a conventional oleoresinous formulation with that of UV curing inks, designed for use on multi-unit sheetfed presses equipped with inline coating stations and allow for either aqueous or UV inline coating, but not both. OS UV-Hybrid inks were developed in conjunction with UV-Hybrid curable coating UVS-4579, an inline quick-setting coating formulated especially for UV-hybrid inks.

Fusion hybrid UV ink from INX International succeeds the firm's VersaCure. INX says it washes up like conventional, oil-based sheetfed inks and runs well with or without inline UV or aqueous coatings. Gloss-backing is minimized when it is UV coated. Fusion is compatible with conventional rollers. The black ink is rated at 1. 65 to 1. 85 density.

TOYO says its Hybrid Echo Soy attains high-gloss printing, with the same de-inking properties as oil-based ink during recycling.

A complete UV ink chart and numerous other resources on coating and curing are posted with this article at graphicartsmonthly.com.

ONLINE: www.airmotionsystems.com, grafix-online.com, harris-bruno.com, us.heidelberg.com, kba-usa.com, komori-america.com, manroland.com, mlpusa.com, mullermartini-usa.com, nordsonuv.com, primeuv.com, superblue.net, sunchemical.com, technotrans.com