Advances in UV-LED Curing Modules and Inks

The introduction of UV-LED curing was initially met with some skepticism. Today, innovations in the technology benefit wide-format printers and more.

By Eileen Fritsch,
Industry Author

UV-curable inks react to controlled wavelengths of ultraviolet (UV) light to form a solid film on the surface of a substrate. Screen printers have used UV-curable inks for years to print text and graphics on durable indoor and outdoor signs, safety labels, fleet markings, and industrial parts.

But changing the mechanisms for how UV light is delivered to the inks has profoundly improved the efficiency, sustainability, consistency, and possibilities of the UV-ink-curing process.

Switching from UV curing systems that use mercury-arc lamps to light-emitting diodes (LEDs) has reduced energy usage by as much as 70%. It also sparked innovations that benefit all types of digital and analog printing systems. UV-LED curing has greatly expanded the type and size of printers that can be developed and the range of materials that can be printed.

“When UV-LED curing was first introduced, some print industry experts were skeptical,” says Stacy Hoge, marketing manager for Phoseon (an Excelitas Technologies brand). “They believed that LED technology could never match the quality or performance of traditional UV curing and required significant investment. Today the case for UV-LED curing has never been stronger.”

Paul Edwards, vice president of the Digital Division at INX, agrees that not all digital printer manufacturers embraced LED curing at first. And initially, only a few applications were addressed.

“Now, LED equipment is the first choice for most wide-format printer manufacturers,” Edwards says. “And ink formulators have been challenged to develop inks for more demanding applications.”

Advances in Curing Hardware

“In the approximately 20 years since the first UV-LED curing lamps appeared in the market, there have been significant advances in LED efficiency and curing lamp performance,” Hoge says.

The advances have led to the following benefits:

Safer Working Conditions: UV-LED lamps are solid-state semiconductor devices. Unlike mercury arc lamps that produce light across the full spectrum of UV light (from 100 to 1800 nanometers), the first Phoseon LED curing units only produced light within the UV-A range, with wavelengths of 365 nm, 385 nm, 395 nm, and 405 nm.

These long UV-A wavelengths can penetrate multiple ink layers and fully bind them to the surface of the substrate.

LED modules that only use UV-A wavelengths don’t expose workers to harmful UV-B and UV-C radiation that can harm eyes and skin.

Fewer Hazardous Materials: UV-LED lamps also don’t contain mercury, so owners of UV-LED printers aren’t charged extra disposal fees each time they replace curing lamps. And unlike mercury-arc lamps, LEDs don’t produce ozone gases that must be extracted by ventilation systems. Some inks are GREENGUARD Gold certified for low chemical emissions in facilities with strict indoor air quality requirements (such as healthcare facilities and schools).

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