Both UV (ultraviolet) and EB (electron beam) curing use electromagnetic radiation, which is different from IR (infrared) heat curing. Although UV (Ultra Violet) and EB (Electron Beam) have different wavelengths, both can induce chemical recombination in the ink’s sensitizers, i.e., high-molecular crosslinking, resulting in instant curing.
In contrast, IR curing works by heating the ink, producing multiple effects:
● Evaporation of a small amount of solvent or moisture,
● Softening of the ink layer and increased flow, which allows absorption and drying,
● Surface oxidation caused by heating and contact with air,
● Partial chemical curing of resins and high-molecular oils under heat.
This makes IR curing a multi-faceted and partial drying process, rather than a single, complete curing process. Solvent-based inks differ again, as their curing is 100% achieved by solvent evaporation aided by airflow.
Differences Between UV and EB Curing
UV curing differs from EB curing mainly in penetration depth. UV rays have limited penetration; for example, a 4–5 µm thick ink layer requires slow curing with high-energy UV light. It cannot be cured at high speeds, such as 12,000–15,000 sheets per hour in offset printing. Otherwise, the surface may cure while the inner layer remains liquid—like an undercooked egg—potentially causing the surface to re-melt and stick.
UV penetration also varies greatly depending on ink color. Magenta and Cyan inks are easily penetrated, but Yellow and Black inks absorb much of the UV, and White ink reflects a lot of UV. Therefore, the order of color layering in printing significantly affects UV curing. If Black or Yellow inks with high UV absorption are on top, the underlying Red or Blue inks may cure insufficiently. Conversely, placing Red or Blue inks on top and Yellow or Black underneath increases the likelihood of complete curing. Otherwise, each color layer may require separate curing.
EB curing, on the other hand, has no color-dependent differences in curing and possesses extremely strong penetration. It can penetrate paper, plastic, and other substrates, and even cure both sides of a print simultaneously.
Special Considerations
White underlay inks are particularly challenging for UV curing because they reflect UV light, but EB curing is unaffected by this. This is one advantage of EB over UV.
However, EB curing requires that the surface be in an oxygen-free environment to achieve sufficient curing efficiency. Unlike UV, which can cure in air, EB must increase power more than tenfold in air to achieve similar results—an extremely dangerous operation requiring strict safety precautions. The practical solution is to fill the curing chamber with nitrogen to remove oxygen and minimize interference, allowing high-efficiency curing.
In fact, in semiconductor industries, UV imaging and exposure are often conducted in nitrogen-filled, oxygen-free chambers for the same reason.
EB curing is therefore suitable only for thin paper sheets or plastic films in coating and printing applications. It is not suitable for sheet-fed presses with mechanical chains and grippers. UV curing, in contrast, can be operated in air and is more practical, though oxygen-free UV curing is rarely used in printing or coating applications today.
Post time: Sep-09-2025
