April 2013 Issue 54

Lawrence Dalton’s industry Digital cartons Hybrid printingNorth Print & Pack preview

digitalprinterTechnology and business strategies in digital print May 2013 Issue 55

Super-cool

Plus:

Open up opportunities with EFI VUTEk’sCool Cure LED curing technology

cover_may_Layout 1 03/05/2013 09:35 Page 1

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EFI believes in the maxim of giving itscustomers a choice, and that this isdependent on various criteriaaccording to what type of output isneeded, both at the current time

and in the future. With green principles andgreater adherence to environmental condi-tions now becoming more topical, eco fac-tors also have to be considered when makingthe decision about which wide format printerto choose.

Considerable publicity has been given inrecent times to the incorporation of LEDlamps in UV-curable print platforms of alltypes and sizes, yet few manufacturers thusfar have included them as options in theirwide format engines. Early on, EFI recognisedthe potential and the benefits of offering itscustomers an alternative to mercury arc curinglamps, and this led to the development andsubsequent introduction of the VUTEkGS3250LX 3.2 metre solution and the morerecent two metre GS2000LX.

A major element leading to the adoptionof LED curing has arisen because of the undisputed disadvantages of mercury arclamp technology, including its relatively hightoxicity and the generation of high levels ofinfrared heat. Because LED lamps emit UVwithin a very narrow band of wavelengths,there is no infrared present and the subse-quent reduction in heat is a key contributor tothe reasons why this alternative curingmethodology is proving so successful on UV-curable printers.

Across Europe, companies have investedin the VUTEk GS3250LX because they havebeen actively seeking a more environmentallyfriendly UV-curable printer. Feedback hasconfirmed that, for these businesses, choos-ing this platform which uses LED curinginstead of conventional mercury arc lampshas opened up a whole new raft of materialswhich previously could not be printed andcured successfully using this ink formulation.Formerly, problems have arisen because anysubstrate or surface which is intolerant of heatis going to suffer detrimental effects when itmeets a conventional UV curing lamp. The

results can be badly buckled and warpedsubstrates; worse, undesirable head crashescan bring damage to the printer itself.

The VUTEk GS3250LX has quickly made aname for itself in being able to work with dif-ficult media, with its ‘cool cure’ technologymeaning that even the most unlikely materialscan be handled. As well as being suitable foruse with thin stocks, one company has evendiscovered that it can print direct to bubble-wrap with excellent results. This means thatthe use of LED UV lamps in an industrial-strength wide format printer now enablesprint service providers to experiment withdifferent types of substrate and come up

with novel and innovative production ideasthat have not been possible before.

Rumours that speed and efficacy are bothcompromised with LED curing are alsounfounded. The throughput speeds of theVUTEk GS3250LX and its smaller counterpartmatch those of equivalent printers using mer-cury arc lamps, with high quality colour accu-rate results being guaranteed. Users have alsocommented that adhesion is excellent withEFI’s inks, and that the print heads tend tostay cleaner for longer periods because thelamps’ instant start-up means that they can beswitched off between print runs.

The economics of the VUTEk GS3250LX

also appeals to companies wanting to reducethe running costs and energy levels of theirproduction equipment. Mercury arc curinglamps lose their quality of emission and theirpower over a finite amount of usage andperiod of time, having a typical life span ofonly 1000 hours. The start-up time needed forthem to reach maximum intensity also wastespower and is time consuming. However, LEDcuring arrays have an instant warm-up so canbe turned on and off when needed. Theirsolid-state construction means that theyshould be able to produce tens of thousandsof hours of active life, yet they cost a fractionof the price in power terms, with users

reporting vastly reduced electricity bills.For companies wanting to invest in a VUTEk

printer and opting for versatility and overallcost savings, along with the greener proper-ties achievable with LED curing, then there isthe choice of the GS3250LX 3.2 metre wideplatform or the two metre GS2000LX. Thosethat feel more at home with a machine con-taining conventional lamps can aim for the 3.2metre VUTEk QS3 Pro or the smaller QS2 Proat two metres. Adding the option of EFI’sOrion architecture will bring additional bene-fits such as greyscale printing to all of theseprinters, along with other features includinglower ink usage and remote diagnostics.

The benefits of LED curing are now a reality for EFI VUTEk users, giving them a widerrange of substrates to choose from, and therefore more applications to offer.

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Playing it cool Mercury vapour lamps distribute their energy over a broad spectrum of 200-800nanometers, and only 5% of the energygenerated is used for actually curing theUV ink, while the remaining 95% is con-verted into heat. This heats the inks andsubstrates, especially the lamp housing,where fans suck the heat from the mercuryvapour lamps. Therefore, many large formatprinters work with open panels. The dissipated heat cannot be captured welland heats the entire press, which is not beneficial.

LEDs are semiconductor elements thatare applied to a substrate. The exact composition of these materials determines,among other things, the wavelength atwhich the LED has its greatest power out-put, so today a wide selection of diodeswith wavelengths from the visible to theultraviolet range is offered. For UV inksthere are UV-LEDs with a peak in the rangeof 395 and 365 nanometers, which areboth used for UV inks.

However, these LEDs emit considerablyless light and therefore need to be assem-bled in the LED lamps in several rows to asurface light. They also generate heat. It isestimated that 20% of UV radiation is usedfor curing and 80% of the visible light isconverted into heat. This heat can be dissipated by air or water cooling, to avoidheating of the substrate.

Based on usage 12 hours a day, five daysa week, and 52 weeks per year, curing with

EFI VUTEk GS3250LX specifications

• Eight colour plus white UV printing• Print speed: up to 223 square metres

per hour• Dual resolution: 600 or 1000 dpi• Media: flexible or rigid up to 3.2 metres

and up to 5.08 cm thick• Footprint: 168 x 630 x 168 cm• EFI Fiery XF RIP• EFI Inks: CMYK, LC, LM, LK, W – supplied

in five litre containers

EFI VUTEk GS3250LX

mercury vapour lamps consumes 46,800kilowatt hours. For LEDs, at 80% utilisationthe printing time is 9.6 hours x 3.6 kW, whichequals 3.456 kWh per day. For 5-day weeksand 52 weeks per year, the LED thereforeconsumes about 9,000 kilowatt hours a year.So 37,800 kilowatt hours can be saved annually with LEDs, in comparison with mercury vapour lamps. n

Mercury lamps versus LED curing

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