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DRYING/CURING EQUIPMENT -- Avoid Half-baked Systems

March 2002
BY ERIK CAGLE


When you have the need for speed (press speed, that is) the last thing you want is some clunky drying/curing system that is not able to keep pace.

Systems that generate high UV output to cure difficult colors and the heavy laydown of inks and coatings at high press speeds are highly sought, according to Dave McDowell, UV product manager for UVTechnology. Minimizing the temperatures of the web allow for printing on films and thermal-sensitive substrates.

"As print quality improves, demand has grown for greater image quality and impact from non-traditional substrates," McDowell states. "In many cases, printers are seeking to acquire this work to replace lost business in other areas due to economic slowdowns."

UVTechnology has introduced Maxim single- and multi-lamp curing systems for narrow web presses. Maxim systems feature a reflector and lamp design to increase useable curing energy. The standard closed-loop heat management system and optional cool UV upgrade reduce web temperatures, significantly allowing heat-sensitive substrates to be run with heavy ink and adhesive coatings at higher press speeds.

Competitive print markets continue to drive customers to focus on copies per hour and cost per copy, according to Ken Zak, director of marketing and business development for MEGTEC Systems. The subsequent performance requirements for dryers include reliability at maximum press speeds and the flexibility to efficiently process a wide range of papers, paper weights, web widths, ink coverages and compositions.

"The dryer must accept a variety of input materials and deliver high-quality signatures that have sufficient retained paper moisture for easy handling downstream," Zak notes. "Dryers must exhibit low running costs and high uptime, and operate with no web wander or marking that could cause reductions in press speed. Reduced paper waste and low energy consumption are very important, as well. In short, dryers must do what it takes to help the printer maximize his pressline profitability."

New Designs

MEGTEC Systems introduced the Dual-Dry RTO and Dual-Dry OMEGA drying systems at DRUPA 2000. Both units incorporate three major design innovations. The Dual-Dry air bar system provides enhanced web stability on high-speed, wide web presses.

The systems include an integrated regenerative thermal oxidizer (RTO) section for energy-efficient operation and high volatile organic compound (VOC) destruction capabilities. The 95 percent effective heat exchanger allows both dryers to run with zero gas consumption under most print conditions. The systems utilize a conditioning zone featuring Triton ES evaporative cooling technology. The ES seals ink surfaces to minimize solvent condensation and folder marking.

Many customers seek drying/curing systems that allow them to use various types of coatings on a range of paper stocks, while curing the coatings at top press speeds without the threat of picking or blocking the loads, according to William Fuchs, president of FDV Inc.

FDV's answer to this need is a package it calls the Total Drying System. This system—custom-designed for individual needs—features PLC controls and touchscreen operations. "This allowed us to integrate our software with that of the original equipment manufacturers and now our systems operate within the press control consoles," Fuchs states.

According to Ed McLoughlin, president of Oxy-Dry Corp., many customers are seeking cost-effective methods of producing quality jobs that match the needs of their customers at the press speeds available on high-speed presses. They also want versatile drying/curing systems that allow them to take full advantage of their presses' print quality and speed capabilities, and boast ease of operation with minimal maintenance requirements.

Oxy-Dry's offerings include the DuoTek IR drying package, which employs short-wave IR along with a medium-wave IR source, coupled with an extremely efficient method for providing high-volume hot air. The result is a system for drying aqueous coatings that is very cost-effective to both install and operate. The Oxy-Dry DuoTek UV curing system employs a "shutterless" lamp housing and uses high-volume air for cooling, virtually eliminating the maintenance problems associated with traditional shuttered and water-cooled UV systems. Unique to the DuoTek UV curing system are the infinitely variable output UV lamps providing up to 800 watts per inch of UV curing power.

"The Oxy-Dry DuoTek IR system can offer significant cost savings with its unique combination of short-wave and medium-wave IR drying, yielding quick turnarounds with low operating energy consumption," McLoughlin says.

Dry Sheets, Webs

Through two divisions, Heidelberg offers drying and curing solutions for both sheetfed and web presses. John Dowey, vice president product management/ sheetfed for Heidelberg USA, feels customers are seeking single-source responsibility from their vendors and demand the highest performance and the widest possible window of operation. Reliable and seamless integration into press systems is also of importance.

Heidelberg is the largest manufacturer of infrared/hot air dryers worldwide. "The DryStar systems give unparalleled performance when it comes to drying ink and aqueous coatings," Dowey says. "But where they really shine is in the area of preserving optimal sheet control, especially on lighter weight papers.

"Since it designs the systems itself, Heidelberg is in a unique position to integrate all delivery components into a balanced concept. The dryer is especially designed to work with the patented Venturi sheet guide plates, and we also have taken power application and fume evacuation into consideration with our PowderStar and CleanStar systems. All components work together."

Heidelberg has partnered with a group of manufacturers, including IST and Grafix North America, to provide customized solutions for applications which are beyond conventional ink and aqueous coating.

On the web printing side, clients desire a compatible dryer that delivers a combination of high print quality, low operating costs, low fuel consumption and high reliability. All Heidelberg web offset dryers (Ecotherm, Ecoweb and Ecocool) utilize a high-volume airbar field that dries the web with higher air volumes and at lower temperatures for improved print quality. The ability to utilize evaporated ink solvents to partially fuel the dryer is an additional fuel saving feature favored by Heidelberg Web customers.

Greg Norris, marketing communications manager for Heidelberg Web Systems, notes that Heidelberg occasionally has customers in the high-quality commercial printing sector that equip their web presses for UV coating and drying/curing, and in these scenarios the UV systems are provided by a third-party vendor.

"Equipping a commercial web press for UV coating could provide the print-quality advantage of being able to produce UV coated products, as well as the environmental advantages of not having to use a conventional offset web press dryer to set inks," he says. "However, in most cases, there are major drawbacks that negate these advantages. Web presses equipped for UV coating generally must be run at slower speeds, significantly reducing their productivity. Also, consumables and some press components (i.e., rollers) must be designed exclusively to accommodate the UV coating process. This can significantly limit the versatility of a commercial web press."

According to Elinor Midlik, president of Prime UV Systems, printers considering a UV curing system seek reliability and high power, high gloss UV coatings, precision system control and an environmentally conscious system. She believes the Prime UV system answers all of these requirements.

"A Prime UV curing system is the most reliable UV system manufactured today," she says. "Another important part of the drying system is its ability to cure at the highest speeds. A high-powered Prime UV curing system will guarantee an instant cure of UV inks and coatings.

"High-gloss UV coatings are demanded by print buyers," she adds. "Our curing systems deliver the highest gloss possible, as well as abrasion and chemical resistance. A UV curing system should also offer superior control. A Prime UV system offers the Smart 2100 control platform, giving the printer precise control of the system so perfect printing can be achieved. Finally, printers need a drying/curing system that will meet environmental regulations both for today and the future. By purchasing a Prime UV curing system, the printer will meet the strict EPA regulations, and avoid permit issues altogether since our dryers eliminate VOCs and are recommended by the EPA as the best available control technology."

Prime UV Perfection dryers are designed to cure UV inks at speeds up to 2,000 fpm and are intended to replace hot air, gas-fired ovens on perfecting web presses. Prime Perfection dryers are controlled by the Smart 2100 control platform, which gives the press operators total control of all aspects of the UV printing system.

Because more printers are doing multicolor work, dryers are becoming necessary for faster turnaround times and higher quality printing, according to Margaret Bain, marketing coordinator for Accel Graphic Systems. Drying systems reduce spray powder usage and setoff or blocking.

"The fastest growing curing and drying technology is probably UV," she says. "Ultraviolet inks and coatings produce bright, intense colors and extremely high gloss."

Accel Graphic Systems manufactures the Tempest hot-air dryer. The Tempest uses PTC thermistors instead of IR elements to accelerate the drying process. The compactness of the delivery area in low-pile presses makes IR drying more problematic because of space, excessive heat and premature wearing of parts, according to Bain. Many of the safety features found on larger IR units are not available on smaller format presses.

Keith Tap, vice president of technical services for Grafix North America, finds that printers are looking for an integrated system for drying and curing that will produce printed products that broaden their market advantage, while delivering consistent results. "The only way to ensure complete success is to provide a system that incorporates state-of-the-art hardware, an organization of parts and service support and, most importantly, hands-on application training after installation startup with continuing after-sale support," he says. "Grafix North America provides focus on the latter by providing its own staff of application and in-field demonstrators dedicated to this process."

Drying Hybrid Inks

The company's award-winning process, CoCure, allows printers to achieve the benefits of UV gloss, curing of hybrid inks on absorbent and non-absorbent substrates—such as static cling, styrene and foil—in-line without the need of a fully dedicated UV press.

Doug Misercola, president of DRI, believes the primary customer considerations are faster drying capabilities, with increased throughput that reduces unit cost and less waste. Print clarity, he adds, is also important as faster drying reduces ink flow and spreading, creating a more clear, defined dot structure while providing improved print quality.

DRI's latest offering is the RA series radiant-air electric IR dryer, available in various heated lengths from 10˝ to 150˝ long. "Our customers have been looking for solutions that will increase productivity and product quality, and we finally have a solution for them. The RA series can be adapted to many drying and heating processes."

Baldwin Technology offers solutions for both drying conventional inks and curing hybrid or UV inks. Neil Kurkjy, marketing manager, believes customers want a system that can dry sheets regardless of press speeds, leading to less waste.

Reducing startup time and enhanced effectiveness are also desired qualities for drying and curing. A drying system must help keep energy costs in check, while a curing system needs controlled temperature within the press and pressroom, providing a better environment for both man and machine.

The Baldwin GraphiSet 4 IR for ink and water-based coatings features less energy consumption due to a new drying module design, touchscreen control and automatic temperature control. Its GraphiCure 6 UV also boasts touchscreen control for easy operation and a refrigerated cooling system, which ensures a constant, low temperature throughout the day.

Bill Bonallo, president and CEO of technotrans america, believes that with customers printing on substrates ranging from 40-lb. litho label stock to static-cling vinyl and 24-pt. board, the drying and/or curing system must be designed and engineered to function in perfect harmony with the sheetfed press delivery. With press speeds exceeding 15,000 iph, sheet control—particularly on lightweight substrates—is critical and will absolutely affect press running speeds.

"The old concept of putting lots and lots of IR emitters in the system and literally cooking the sheet with IR energy is simply not effective on state-of-the-art, high-speed printing presses," Bonallo says. "Achieving curing and/or drying at press rated speeds requires 'smart' system technology that will allow the infinite control of drying energy to the substrate. Although we configure our systems with power outputs that provide rated press running speeds on a wide variety of substrates and levels of ink coverage, nonetheless we like to dry/cure using only the amount of energy necessary to do the job.

"Running at that level normally results in cooler substrate and load temperatures," he continues, "thus having less effect on the potential of effecting the dimensional stability of the sheet, which can affect sheet-to-sheet register on subsequent press passes or off-line finishing, as well as image registration on second pass or second-side printing."

technotrans america recently signed an exclusive agreement with IST Metz, which allows its sheetfed division to be the exclusive representative for IST Metz UV curing systems in the United States and Canada. technotrans provides a line of infrared hot-air thermal drying systems for sheetfed ink- and water-based applications, as well as both hybrid and full UV.

Honle UV America's customers are looking for highly efficient UV curing systems that allow them to successfully cure UV inks with coatings at fully rated press speeds up to 800 fpm in flexo presses, according to James McCusker, president.

"Film creates more challenges when curing with UV," he says. "Customers are now demanding 'cold mirror' technology when processing supported and unsupported film, due to the thermal sensitivity of the stock."

Honle's Advanced Cold Mirror (ACM) UV unit provides a higher peak intensity, while reducing web temperature by 70 percent.

Eltosch North America offers a number of drying/curing solutions. The UV Interstation can be placed after a print unit or over a perfecting unit and is available with dichroic reflectors and stepless power control. The UV End Cure can be used with the Interstation or as a standalone final UV cure, while the Mega System is a combination of IR and thermal air that accelerates the drying of aqueous coatings at maximum speed.

Primarc UV Technology manufactures UV curing lamps (or bulbs). Jeff Bade, sales manager, sees five important criteria a printer should consider when purchasing this component: quality, availability, competitive pricing, technically competent vendors and vendors who are easy to reach (24-hour accessibility).

Primarc recently addressed the fifth criteria with the introduction of its new Website, www.primarcuv.com, that provides an extensive list of UV curing bulbs for printing and coating applications. Prices are listed for convenient online ordering, and credit card and invoicing payments are accepted.
 

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