Will the latest UV drying techs win over sheetfed litho?

Richard Stuart-Turner
Monday, January 25, 2016

Last month IST (UK) launched a service that enables UK printers to retrofit LE-UV, LED-UV or conventional UV drying technology onto installed or secondhand equipment.

The move marks the latest in a long line of developments in the growth in usage of UV technology in sheetfed litho printing in the UK over the past few years.

Heidelberg has also recently entered the UK UV market, showing an LED UV press for the first time in the UK at an open house event in November.

It has already installed more than 20 LED presses in Japan, where there is an energy-saving imperative for businesses, and the technology has also proved popular in Europe, with presses already installed in Switzerland and Germany.

As clients increasingly demand shorter turnaround times and use more uncoated stocks, more and more litho printers are looking for a way to compete with digital printers on short-run work, and UV technology is proving to be the best option in many cases. 

Conventional UV curing, which uses mercury lamps as a UV source, has been around for many years but newer types of UV curing – namely LE-UV, also known to Komori users as HUV, and LED-UV, are currently leading the way (see box).

The main draw of UV curing is that ink dries instantly, saving on storage space and time and allowing work-and-turn or finishing to be completed immediately.

“I think if you’re in the short-turnaround market with offset material it’s a huge advantage as there could be up to three days drying time with certain grades of offset material,” says KBA UK product and marketing manager Craig Bretherton.

“Web-to-print businesses would find the ability to turn around work in a matter of hours a major benefit and would likely charge a premium for that service as well.”

Other factors

The rise in the new UV technology has been brought about not just by an increasing number of manufacturers starting to offer the technology, but additional factors such as inks being better and more readily available.

The new inks used in LE-UV and LED-UV curing also give prints a sharper and brighter appearance than the ‘flat’ results traditionally produced by conventional UV inks.

“If you were to print UV in a commercial market with a commercial press five years ago, the inks had a matt finish and were not oil-based gloss products,” says Heidelberg UK press product specialist Matt Rockley.

“Developments now enable us to match conventional ink with a UV product.”

UV technology can also open up new revenue streams by enabling printers to print on plastics, foils and substrates with a high surface tension. This opens up potential opportunities including loyalty cards and stickers and effects such as UV varnishes and high builds.

One reason conventional UV is seen as a less enticing prospect than newer UV technology is the fact that the mercury lamps the technology uses are likely to be phased out of the print industry over the coming years.

“Now there is an alternative that works and is credible, more legislation will come down on the mercury lamps,” says Bretherton.

Apex Digital Graphics managing director Bob Usher adds: “Conventional UV gives off a large amount of ozone, which has to be ducted out of any print works. LED UV completely eliminates powder spray so the machinery and the print works become completely decontaminated from powder.

“The lamp life is also around 18 times longer than that of a conventional UV lamp, which printers have to continually change.”

But there are drawbacks to all types of UV curing. Owing to their extra sensitivity, UV inks are more expensive than standard inks, adding a potentially large cost to a printer’s consumables bill.

“If you’re a high-volume user it can be up to three times the price but users have found that all the other benefits – such as bringing finishing work back in-house, more floorspace, quicker reaction times and the ability to print on difficult substrates – are worth it as they’re making more money,” says Bretherton.

The actual need for a UV press is also dependent on the type of work carried out by a printer and its typical run lengths.

“If you were to do 15,000 sheets of a job on a long perfector, that might take an hour and five minutes including the makeready, so why would you need dry ink?” says Rockley.

But overall, the new types of UV curing have given more choice and, crucially, the ability to compete back to commercial offset printers in the short-run quick turnaround markets.

Both the supply and demand of the technology is quickly growing and 2016 could prove to be a banner year, particularly with Drupa on the horizon, though this is dependent on how much importance litho press manufacturers and suppliers place on UV at the show. Typically they are keeping tight-lipped on the issue at this stage. 

“It’s real live technology now and everybody that we’ve shown it to is extremely positive about it,” says Bretherton.

Usher concurs: “We’re seeing a lot more enquiries now. What’s accelerating it is the improved economy. Printers are far more willing to borrow and that leads to the ability to take a risk to buy something new. 

“I think the growth in the modern types of UV curing will happen dramatically. Everybody is on the bandwagon and promoting it, UV is the buzzword.”


It may be time to reassess the options for UV drying

john-charnockJohn Charnock, managing director, Print Research International

The benefits in UV curing is that the sheets come off the press already dry and the ability to use inter-deck drying so that the ink from one unit is dry before the next colour is printed. UV is also used when printing on substrates with a high surface tension, such as plastic. 

The challenge with conventional UV systems is that the press has to be cooled with water because of the high heat generated by traditional UV dryers, and this high heat also leads to a risk of fire – not something you want in a print works.

At the time I was buying for St Ives the company had a zero tolerance to fire risk and so all UV presses in the group had to have an automatic CO2 fire suppression system, which is a significant additional cost. This infrastructure was expensive and, combined with the higher cost of ink and higher cost of the UV lamps and curing system, made it prohibitive in many cases.

The massive benefit of LED UV is that the UV drying system is significantly cheaper and the lower heat/energy requirement of LED makes it much safer and therefore a more attractive process. 

LED UV appears to be taking off in Europe both in the large-format arena and the offset arena, but take-up has been slow in the UK as many believe the inks are very expensive and the systems require horrible photo-initiators. 

However, that is not so much the case today as there have been huge advances in the technology; low-migration inks and process systems as well as other developments that make LED UV significantly more attractive. 

That tied with the lower operating costs, fewer emissions, low odour and much lower fire risk make LED UV at least a consideration for new investment.

If you are looking for differentiation, LED UV offers some attractive propositions and I suspect we will see an increasing number of installs over the coming years.


What has been your  experience with new UV technologies?

david-lamdinDavid Lamdin, director, Selsey Press Runs a B2 Komori Lithrone with HUV (retrofit by Benford UV in 2014)

“For short-run jobs HUV is a lot quicker because you can take the job straight out of the machine after printing and do whatever you want with it. Customers especially like the print onto uncoated stocks, which is a lot crisper, sharper and brighter because it’s not soaking in. There’s an increase in ink cost - but for short-run work it doesn’t make much difference - and the metallic inks are also not quite 100% there yet.”

ian-gatfieldIan Gatfield, production director, Wincanton Print Ordered the UK’s first Heidelberg Speedmaster  XL 75 LE-UV press

“We’re a very quick-turnaround print company and the LE-UV will allow us to deal with uncoated stocks and bespoke papers faster and eliminate marking issues. Our press also has Inpress Control so to have that with UV ink will give us such an advantage with quicker makereadies. The inks are up to three times more costly, so for longer runs I could see that being an issue but we’ll run a conventional press alongside the LE-UV press to do those.”

david-blandDavid Bland, director of sales and marketing, Blackmore Installed the UK’s first KBA LED UV press, a Rapida 105, last year

“We’ve seen huge benefits in electricity saving and having a perfectly dry sheet coming out the end of the press means the press is shorter as you don’t need a coating tower or extended dryer. It’s opened up an entirely new market for us, we used to put many more jobs out to digital printers but because it’s such a quick press and quick makeready we’re now able to compete both in the B2 market and on the smaller digital jobs.”


Unlike conventional UV curing, neither LE-UV/HUV nor LED-UV technology use mercury lamps as a UV source

In LE-UV, LE stands for ‘low-energy’ and refers to the power of the lamps compared with standard mercury lamps

In Komori’s HUV technology, 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-output lamps

Both HUV and LE-UV use lamps that are doped with iron. These lamps don’t emit the shorter UV wavelengths that generate ozone, and as a result obviate the need for ozone extraction. Additionally, as they consume less energy they produce less heat, so require less cooling, which helps reduce the power consumption of the UV curing system

In LED-UV the LED stands for  light-emitting diode. The UV they put out 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, however they do generate heat, so heat extraction is still needed


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