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Why UV LED Curing Printers are the Better Investment (English)

Mercury vapour lamp technology has been around since 1880. Today, mercury lamps are inside most UV curable wide format inkjet printers. One of the major disadvantages of mercury lamp technology is the broad range of wavelengths they emit, including a lot of infrared — and therefore: heat.

Although you could theoretically keep refining this old technology, that wouldn’t be future proof. A printer manufacturer that would invest in improving mercury lamp technology would show little understanding of environmentally sound development strategies. Not only do mercury lamps contain highly toxic mercury (a problem at the lamp’s end of life), they may also generate ozone (a problem in usage). But what may tilt the scales entirely against this UV curing technology is that it keeps printers from broadening their capabilities.

The alternative to the mercury UV curing lamp is the UV LED lamp. LEDs don’t emit ozone at all and they are completely mercury free. But more importantly, they enable printers to experiment with materials that normally aren’t suitable to be printed on with UV curable inks and thus dramatically expand the range of applications they can offer to customers.

LED arrays as found in UV LED curable wide format inkjet printers allow for faster finishing of jobs. A printer like the Durst UV Omega 2 allows for much faster operation than comparable mercury lamp based printers because there is no lamp warm-up time and no shutter open/close delay. UV LEDs are turned on only when they’re actually over the substrate and that typically takes only a couple of milliseconds.

Other advantages are: no stray light and big power savings. In fact, LED technology may reduce a printer’s power bill by up to 80% — with Durst claiming 65% reductions from using the UV Omega 2 because of the air-cooled 395nm-wavelength LED lamps the printer uses.

The alternative to the mercury UV curing lamp is the UV LED lamp.

Advanced UV LED curing capabilities

The “instant ON/OFF” feature as used in all areas of curing can achieve matte or gloss finishing with specially UV LED formulated inks. Outside the printing business, the granular control over LED lamps gives coatings and adhesives unique properties.

Those who discuss whether UV LED curing is environmentally sustainable often state that UV LED curing inks are more toxic than others used in the printing industry. This, I found, is wrong. It’s true the narrow UV-A wavelength of most UV LEDs necessitates the use of inks that are formulated specifically for UV LED curing. But it’s untrue these inks are all less healthy to handle and use than others, or less environment-friendly for that matter.

Better quality and higher return on investment

But UV LED will also protect your investment better. A mercury lamp will typically run for 1500 – 2000 hours. The quality of the radiated UV and the curing capabilities will deteriorate faster. Both the reflector condition and age of the bulb will determine the quality of the lamp and whether it’s still fit for UV curing. The lamps themselves aren’t very expensive, but if you add the environmental challenges that come with the disposal of the mercury inside the lamp, the replacement costs a lot more than what you actually pay for a new one.

The biggest manufacturer of LED lamps in the industry, Phoseon Technology, specifies an expected life time of over 20.000 hours of on-time for their UV LED light sources. Given that LEDs are only switched on if they are actually over the substrate curing, the lifetime should exceed the lifetime of a printer.

Phoseon Technology says it can claim this as they have a large number of units in the field for years. Additionally, they constantly have more than 50 light sources in life time testing in their labs, some under odd conditions — for example air exhausts closed on some air cooled units, so they almost can’t breathe.