The increase of UV-curable printing throughout the digital world has not all been straightforward, with one of its disadvantages levelled at mercury arc lamps and their lack of environmental criteria, cost of running and frequency with which they need replacing. When EFI developed its GS series of wide-format printers, on the menu was an option that discarded conventional curing technology, replacing it with LED lamps.

Now well-established among display producers and print houses globally, the current series of EFI wide format and superwide format LED printers have proved their value for incorporating alternative curing technologies, with companies reporting positive results across all types of application. All incorporate EFI’s ‘cool cure’ technology which brings the benefits of LEDs to production platforms to generate excellent quality and high-speed throughput on a very broad range of rigid substrates and flexible materials, including a greyscale option, white ink and continuous board handling.

The use of UV-curable ink has risen swiftly throughout the graphic arts, industrial, functional and speciality printing sectors where digital technology increasingly is employed. The criticisms levelled at the curing process, however, made manufacturers consider options that did not include mercury arc lamps with their reputation for being energy hungry and not particularly eco-friendly, compounded by their average life of around 1,000 hours and lengthy warm-up times.

As a counterpart to traditional UV curing lamps, LEDs have risen rapidly in popularity having benefited from impressive research and improvements during the past two decades. Originally seen as an alternative to fluorescent and incandescent light sources, neither of which is particularly energy efficient, their development transgressed to other capabilities with one of these being their suitability for curing ink.

With UV curing in the digital printing industry using lamp technology which was already established in the analogue sectors of screen-printing and flexo, one of the compromises immediately in evidence was the intense heat levels needed to dry, or cure, ink onto the material. The spectrum required generates high levels of infra-red and deflecting this away from the media surface effectively is further hindered by the design of print-head arrays and the small space in which they are expected to function.

LEDs originally were used for low power illumination, being semi-conductor devices which convert electricity into light. Their ability for those semi-conductors to be engineered so that the electric current could also be converted into a heated light source opened doors into new industries, with print being one of them. Original doubters of their efficacy in the wide-format sector have largely been thwarted because of the success of EFI’s LED printers, and the use of LED curing in the company’s Jetrion narrow-web platform. 

Users of EFI’s LED technology have quickly reported their experiences of switching to a printer that incorporate ‘cool cure’ technology instead of conventional curing lamps. The two key bonuses which were evident immediately have been first the ability to print onto all materials without fear of surface damage and, secondly, the removal of the need to swap out the lamps after a limited time period of around 1,000 hours.

Other benefits have also manifested themselves, however, with a notable reduction in running costs when compared with mercury arc curing processes. LED lamps have an instant start-up so that there are no delays incurred during unwanted warm-up times, a feature which also reduces energy costs and power wastage. Additionally, their use involves no generation of VOCs (volatile organic compounds), another advantage for users striving to work in a greener environment.

But without doubt the most important and immediate advantage noted by users has been the fact that, across all rigid and flexible materials, concerns about material handling are virtually eliminated. With mercury arc’s tendency to damage sensitive surfaces because of the intense levels of heat generated, LED lamps have quickly proven themselves to be suitable with even the most sensitive and difficult media types. This has removed problems such as warping which can lead to head strikes, and resulted in greater versatility across different kinds of substrate, including very thin and recycled products, thus broadening the range of application type which can be printed.