Part 1 of 2
By Cassandra Balentine
The range of effects achievable with UV-curing in direct to object (DTO) printing is extensive, ranging from vivid spot colors, metallic finishes, tactile effects, foiling, functional coatings, Braille, and security features.
Stacy Hoge, Phoseon marketing manager, Excelitas Technologies Corp., points out that UV inks adhere to a range of substrates giving the user substrate versatility and eliminating the use of labels.
Hugo Gonzalez, senior segment specialist, industrial products, Mimaki USA, Inc., says effects like gloss, matte, and metallic finishes as well as ADA and Braille signage, and vibrant colors are possible with the help of UV.
UV also allows printers to provide different sensory effects—visual and touch, which can go together for added impact. “An example of this would be a process for printing on wood, where both the structure and color combined can create what looks and feels like a high-quality wood finish from a much lower quality wood source. It is the combination of structure, look, and feel applied to many different substrates which can allow designers to be very creative in the decoration, with the range of different material types and applications,” notes Paul Edwards, VP – digital division, INX International Ink Co.
Chris Davis, head of sales, web and industrial, IST America, stresses that each effect requires a specific curing strategy to ensure proper adhesion, durability, and appearance.
The UV lamp can play a big factor in the finish of the ink—gloss versus matte—and it’s also vital in raised or textured effects. “When you jet a sizeable amount of ink, the lamp needs to cure all of that ink so you can achieve the desired dimensional effects,” says Michael Perrelli, sales and marketing director, Innovative Digital Systems.
Edwards explains that UV digital can place material down when printing to create a 3D effect. “This provides stunning effects not possible by other methods, creating differentiation from previous printing processes. Other effects can also be achieved. For instance, UV technology for a hot foil effect. It acts as a glue, which only becomes tacky during the hot foil process, therefore creating digital hot foil effects.”
With Mimaki UJF Series printers, gloss and matte finishes are achieved through the use of clear inks to create various gloss levels. “UV LED lamps can be also controlled to print two layers—matte color and clear gloss—at one time through the use of modular UV lamps.”
Thomas Lang, digital applications manager, Inkcups, shares that some of the most popular, and striking, special effects possible with DTO UV inkjet printing are those achieved through the use of clear varnish applied and cured the same way as inks. “This is typically referred to as spot varnishing and it can be used to create subtle, yet striking special effects.”
Lang offers an example from FESPA 2024. “One of the most sought-after designs produced on the Helix ONE used only clear UV-curable varnish, jetted onto semi-opaque drinkware to allow full transparency where the design was, contrasting with the matte finish. When applied selectively, spot UV varnish can also be used to create an embossed effect on glass. Alternatively, an etching effect on glass is achievable by printing white ink at a lower opacity, or a stained glass effect if printing in color without a white to allow light to shine through. The key to all of these effects, however, is UV curing, because it is the precision it enables that makes them possible.”
Lang says another possibility is where UV-curable primers are jetted through a printhead to be placed directly under a logo, making for a seamless inline process for pretreatment and print in one.
Worth the Effort
Special effects add value to printed output by offering sensory pleasing aesthetics, from a sleek coating or metallic look to a textured feel. This is all possible with the help of UV printing and curing technologies.
Oct2024, Digital Output
