First of all we should state that UV-curing has been in the market for over 30 years. UV-curing lamps have been used for curing liquid laminate and for curing screen printing inks for many years before UV-curing technology was applied to inkjet inks.
Unlike solvent and waterbased inks that dry naturally on the paper or at most with the help of a small fan or heat bar. UV-curable inks are dried or cured through a photomechanical process by using ultraviolet lights as they are printed.
As the ink is distributed onto the paper it is immediately exposed to UV lights (located on both sides of the printing carriage), so the ink goes from a liquid state into a solid one with almost no evaporation of solvents. The printheads jet the special ink onto the surface; the light from the printheads is at a special wavelength to react with the photo initiator chemicals in the ink to turn the liquid ink into a solid, in milliseconds.
One of the reasons UV-curing printing is considered more ecofriendly is the fact that the UV light dies the ink instantly, so there is no time for it to evaporate or to release VOCs into the environment, which results in a very low carbon footprint from the process.
The printer design has to keep stray light away from printheads; you don’t want non-printing ink to solidify (cure) on the surface of or inside the nozzle. Since newer better inks have the downside of light cure, they may be sensitive to sunlight. As a result you have to protect the ink and printheads all the more. In addition to protecting the printhead from extraneous light, you also have to protect it from reflections from any shiny printable materials back up into the printheads.
For a couple of years now the whole UV-curing process has become more eco-friendly, since now more and more companies are using UV LED curing lamps instead of the traditional mercury arc lamps. UV LED lamps produce less heat (more substrates can be printed), use less electricity and last longer then mercury-arc lamps.
The fact that UV-curable inks dry so fast, leaves no time for it to smudge or spread, so you can get much finer and sharp details. It is also beneficial since the faster drying times save money and you do not need to wait for the ink to dry before performing finishing operations: folding, binding, cutting, trimming, etc.
UV-curable inks can be used on a variety of materials, such as plastic, glass, metal, paper, wood, etc. Basically if it can fit onto the printer you can print it, so the possibilities are endless. These inks are ideal for outdoor applications since they are weather and fade-resistant. They are also less prone to scratches and scuffs while transporting, plus they have solvent and hardness resistant.