The proselytisers claim that most new press installs use UV curing and anyone not jumping on the bandwagon is going to find themselves at a competitive disadvantage. There’s the suggestion that printers in the UK are on the back foot compared with their continental and Asian colleagues in adopting these new technologies.
So what makes UV the perfect cure? And what are its drawbacks? And why exactly is the UK apparently so far behind its European and Japanese counterparts? PrintWeek investigates.
What are the trends in the market that make UV attractive?
It’s no secret that the past few years have seen significant changes in the type of work and the service levels that customers want. There is demand for shorter turnaround times, and having to wait for a job to dry before you can print the other side or finish it may mean losing the job to a faster printer or process, such as digital, or it not being produced at all.
There is also now increased demand for uncoated stocks that can be challenging with traditional oil-based inks. The inks take much longer to dry, needing a day or even several days. So if the client wants the job yesterday and on trendy uncoated stocks, something’s got to give.
What are the benefits of UV?
Curing means the ink dries instantly. That’s great for on-demand work because a dry sheet can go straight onto the next process, whether that’s printing the other side of the sheet or finishing. Another upside of that is there is no need for spray powder to keep wet sheets from setting off. Another benefit of instant drying is that on absorbent stocks – primarily uncoated ones – the ink dries where it was printed rather than sinking into the paper, which means sharper, brighter print and no dry-back. Then there are plastics and synthetics, which oil-based inks have a problem adhering and drying on. UV curing gets around that too.
So if UV is so great why isn’t everyone using it already?
UV is more expensive and more complicated than normal ink. The cost of standard UV inks is about two or three times that of oil-based ink and you need to fit UV curing lamps to your presses. The historical UV curing systems use a lot of energy, partly to power the lamps, partly to keep them cool. Those lamps also produce ozone, which, while it’s a good thing in the upper atmosphere, is a toxic gas that needs to be extracted from the pressroom, again adding cost and complexity.
Confusingly, not all UV curing is the same. A further complication is that the newer UV lamps and inks are called similar things when they are really quite different, and different things when they are the same. It all sounds like something out of Alice in Wonderland.
Conventional UV curing uses mercury lamps as a UV source. These emit radiation in a broad spectrum – from 200nm and up. At 240nm and shorter, the UV creates ozone, which must be extracted. The lamps also produce heat, which can scorch or melt the substrate, so this needs to be cooled, which requires additional energy. Typically, one third of the energy used by a UV curing system is used for cooling.
There are two newer types of UV curing emerging, which use different lamp technologies. This is what is termed by some vendors – notably Komori – HUV, and by others LE UV. LE stands for ‘low-energy’ and refers to the power of the lamps compared with standard mercury lamps.
In HUV, the H stands for ‘highly reactive’, which refers to the nature of the inks. They are more sensitive, so don’t need as much energy as standard UV inks and can be used with lower powered lamps.
Both HUV and LE UV use lamps that are doped with iron rather than mercury. These don’t emit the shorter UV wavelengths that generate ozone, which removes the need for ozone extraction. As they are lower energy they produce less heat, so need less cooling, which helps reduce the power consumption of the UV curing system.
LED stands for light-emitting diode. The UV they emit is in a much narrower band of wavelengths that don’t generate ozone. LEDs are more efficient at converting electricity to electromagnetic radiation than conventional bulbs, although they are by no means perfect and do generate heat, so heat extraction is still needed. LED curing is promoted by Ryobi and Sakurai.
Why are Japan and Europe ahead?
UV curing, and latterly HUV and LED UV, dominate the Japanese commercial print market. UV was adopted because of space constraints. Printers didn’t have the space for stacks of work in progress nor for a coater, IR dryer and extended delivery on the press. Following the Fukushima nuclear disaster Japanese firms were required to reduce power consumption by 15%. For printers running UV that made LE/HUV and LED UV attractive.
With the success of LE/HUV and LED UV at home, the Japanese press manufacturers are leading a push in Europe.
“In Europe, 50% of Komori sheetfed sales are HUV,” says the manufacturer’s UK sheetfed sales director Steve Turner. “Some French sites haven’t just got one machine – they’ve gone for a second or even a third.”
Ryobi has also chalked up successes with LED UV presses in France, Switzerland, Austria, Germany and Luxembourg.
However, if you drill down into the situation in Europe, it emerges that the market where things have taken off is France, although it’s not clear why it’s a special case.
“It’s France that’s really picked up HUV, with more presses installed there than the rest of Europe,” says Sun Chemical Europe energy curing products marketing manager David Sexton.
So will UV become more widespread in the UK?
There is an argument that, in fact, the UK is ahead of the commercial UV curve, it is just behind in the uptake of these latest LED, LE UV and HUV iterations.
“In the UK, UV is already used in commercial print in a way that doesn’t happen in Europe,” says Stehlin Hostag managing director David Ward. “HUV is taking off in Europe because conventional UV never got established.”
There are now print sites in the UK adopting HUV/LE UV (see case studies), and LED, with more set to follow later this year. The first firm to get an LED UV press is B&B Press in Rotherham, which is currently commissioning a Sakurai machine, with a second due to arrive in September. According to business development director Dan Dean, the firm considered its options very carefully.
“We test printed our most problematic jobs in Japan and took the results to our top 10 clients,” says Dean. “Getting no negative feedback was the catalyst.”
Not a cure-all
“UV is a very good solution when it is appropriate – and I’m an advocate of UV,” says Heidelberg product marketing manager Matt Rockley. “But I question whether it suits the commercial printer as much as the zeitgeist suggests.
“I would urge those tempted to explore this technology to calculate the likely ROI based on facts rather than emotion – always look at the total cost of ownership.”
Is the price right?
While UV inks are two or three times the price of standard inks, the new generation of HUV/LE and LED inks command even more of a premium, as much as 50% more than standard UV inks, or four or five times that of normal inks. For some companies, that could add up to an extra £250,000 per year in consumables costs if they want to be able to offer quick turnaround work conventionally as well.
“Can the commercial printer who wants UV for 20% of their jobs that are currently problematic justify increasing ink costs for the other 80% of their work?” questions Rockley.
Even the strongest advocates of new UV admit that for some commercial work, such as magazines, it’s not the right option, and that the current way of working with a seal and spray powder can be as quick, nearly as easy and much more economical on the coated papers that still represent the bulk of most firms’ stock.
So new UV can’t claim to be the panacea for all of sheetfed offset’s ills, but it does offer a remedy for some common commercial print ailments.
Case study: Image Data Group
Image Data Group took delivery of its Komori Lithrone GL540 H-UV at the beginning of April. The five-colour B1 press came straight from Ipex’s Eco Zone.
“We spent a lot of time looking at this press – a couple of years or more. We did a lot of samples and tests and we waited until it and we were ready,” says managing director David Danforth.
The H-UV suited the direction Danforth believes IDG’s job mix is moving
“A lot of work that was previously produced on recycled grades is now going onto uncoated,” he says. “We can turn around uncoated stocks much more quickly and we can print onto plastics for the POS side of the business. And it opens up other markets. It widens the range of jobs that we can accept and applications we can address without getting out of our comfort zone.”
Case study: Selsey Press
Sussex firm Selsey Press was the first UK company to opt for Benford UV’s retrofit of HUV lamps, signing up for this for its six-year-old five-colour B2 Komori Lithrone at Ipex. Prior to HUV, the firm would never have considered UV curing.
“The main reason for the investment was turnaround time, especially on heavy coverage, uncoated jobs,” says Selsey Press director David Lamdin. “We were leaving some jobs as long as a week – we are fussy about quality – although typically standing time was two or three days.”
The press it converted has always been used for short runs; longer-run work better suited to standard inks will still be produced on its other presses.
“When we learned that we could retro fit rather than go for a new press it was a no-brainer,” says Lamdin. “It widens our substrate horizons and we can also look at doing spot UV ourselves.”