By Melissa Donovan
New flatbed and roll, as well as hybrid, wide format printers were introduced in the last 12 months. Many of these printers’ debuts coincided with new or updated ink sets. This was apparent around Spring trade show season in relation to UV, UV-curable, and UV LED printers. The UV ink market’s changing dynamics are influenced by an interesting mix of hardware advancements as well as the demand for an ink set that offers a level of flexibility ideal for roll and hybrid devices. Other trends causing hardware and ink manufacturers to revisit existing UV ink formulation or start fresh with an original ink set are related to new substrates and applications.
Above: Wallcovering printed by Color Reflections out of Philadelphia, PA using Canon UVgel ink.
LED’s Effect on UV
The UV ink segment has changed in a number of ways over the last five to ten years. Much of its evolution is dependent on the introduction of LED curing lights and the discontinued use of mercury-based metal halide lights. In addition, printhead advancements influence the newest iterations of UV ink.
“UV ink is considered one of the most growing ink solutions in large format. In its initial stages it did not receive much success due to competition with latex, solvent, and water-based ink systems. It took its time becoming more consistent and stable in order to gain market share,” shares Sohil Singh, VP, StratoJet USA.
The move from mercury-based bulbs to LED lights inside of printers is part of UV LED ink’s success. “The UV ink market has expanded with the proliferation of UV LED technology. The lower temperatures of LED systems enable printers to use UV technology for heat-sensitive materials without damage, which greatly extends the applications in which UV ink is a viable option. Technology has decreased the carbon footprint of UV printing as UV LED gains a foothold. UV LED systems use less power to cure than traditional UV and are equipped with an instant off/on function, which also helps to save energy and reduce its impact on the environment,” explains Angela Argit, marketing manager, Polymeric Group.
“With the widespread transition from mercury- to LED-based curing in most modern UV printers, UV inks deliver faster turns and stronger adhesion, greatly increasing its popularity. As a result, manufacturers invest in new formulations to continue improving overall ink adhesion and, in some cases, offer more than one ink option for the same output device to expand versatility,” agrees Dan Johansen, marketing manager, commercial printing business, Ricoh USA, Inc.
Ken Parsley, product manager, UV LED inks, Mutoh America, Inc., cites this transition is probably the biggest change in UV ink. Not only making the print process and ink safer to use, but developing flexible inks that work well on hybrid printers that print on both rigid and roll media.
While the change from mercury to LED is instrumental in expanding available substrate options, it also presents new ink performance requirements. “Metal halide provided a very powerful cure across the full UV spectrum—UV -A, -B, and –C—and left no room for adaptation. LED on the other hand only emits UV-A, but allows a lot more control over the curing, which means optimizing the wavelength to more narrowly suit a specific purpose. That in turn allows for using less of certain ink components and makes it possible to create more budget-oriented inks or introduce other elements to better control the ink’s performance,” explains Volance Carlin, product manager, Mimaki USA, Inc.
Ink advancements are often coupled with improvements in printheads, shares Deborah Hutcheson, director of marketing, North America, Agfa Graphics. “Over the past ten years, printheads changed from 80 picoliters to now the lowest is three picoliters. This influences ink characteristics in many areas like viscosity, amount and size of the pigment, the pigment load, and dispersion. With a drastically reduced droplet size, we enjoy the benefits of significantly faster productivity and extreme output quality.”
“Furthermore, many new UV inks are introduced for specialized functionality on specific media or substrates to enable industrial or specialized applications in décor, architectural materials, glass decoration, and object decoration,” shares Randy Paar, marketing manager, Canon Solutions America.
Driving New Ink
Hardware and ink manufacturers revisit and tweak existing UV formulations in response to media usage and application trends. These demands also lead ink chemists to introduce entirely new UV ink sets.
There is an overall demand for a flexible UV ink set that run on one device and print to multiple substrates. The goal is for UV printers to be more productive because a shop will not need two or three different print technologies to print customers’ jobs, but can simply use a single device in most cases, according to Parsley.
Material composition is an important consideration. “With the newer LED cured inks, print service providers (PSPs) can now print on media that, in the past, may have been too sensitive to the high heat of mercury vapor cured inks. In addition, the growth in fabric offerings has been supported by the ability to direct print with LED cured UV inks,” says Paul Roba, OEM relationship manager, Avery Dennison Graphics Solutions.
Media previously not printable includes clear and backlit materials. “With clear and backlit material increasing in the market this has pushed a lot UV ink manufacturers to re-think their white inks—as well CMYK colors—to produce better output,” adds Singh.
“In the last five years or so, we’ve seen the rise of more exciting substrates. Clear acrylics, some of which are pre-treated by the manufacturer for ideal ink adhesion, are increasingly popular. And brushed aluminum panel became widespread overnight, thanks in large part to its popularity with sports clubs and fitness centers. Boundary-pushing substrates tend to be popular in signmaking, retail, and architectural applications, so having inks that work with these substrates is helpful,” notes Johansen.
Untraditional materials are gaining attention and changing how UV ink is constructed. “Glass and metal are two typical adventures for UV ink, but the latest UV inks show good adhesion to these materials without using a primer. Flexible and foldable media are also UV ink applicable now and offer adhesion and durability,” points out Juan Kim, CEO, VALLOY Inc.
UV ink design evolves to support industrial and specialty applications. Paar points to a UV ink in the Canon portfolio designed with a hard surface for superior chemical resistance. “This makes it ideal for chemical etch applications where the ink is used as a chemical mask in the production process. Another one is designed with elongation characteristics that are ideal for membrane switch overlay decoration,” he continues.
”New applications are the biggest driver for new UV ink formulations. The end use requirements change and often exceed the performance requirements of the existing ink. The balance the ink formulator always has is meeting the new requirements while maintaining print quality and performance on the production floor,” explains Terry Amerine, VP, marketing and sales, Polymeric Group.
Carlin agrees, citing today’s applications as incredibly diverse and challenging the ink in different ways. “From adding texture with significantly more depth than previously possible to creating dynamic prints that change with lighting conditions. Or using UV LED printing as part of a manufacturing process where the technology has to be molded in to meet the needs of the production line.”
Expanded color gamut is another request addressed by new ink sets. “One of the most obvious improvements is the expansion of the color gamut our inks address,” admits Mark Goodearl, senior ink product manager, EFI. It was once the case where having a six- or eight-color printer was considered a necessity to do point of purchase quality work, but EFI improved its ink color gamut and print modes, so more of its customers find they can produce a higher percentage of sellable output using only four colors.
“When customers get that type of capability with their inks, not only does it make high-quality work easier and more efficient to make, but it can also dramatically increase productivity when producing distance viewed work,” he continues.
Print providers interested in UV ink are also considering sustainability when looking for new ink sets. “Market dynamics and environmental regulations are pushing the boundaries of UV ink developers to consider other components to positively impact the air quality and meet safety requirements. Inks that achieve GREENGUARD Gold certification open the door for new applications in healthcare facilities,” shares Hutcheson.
Singh also shares that media quality is an issue that influences new UV ink compositions. “With production and competition increasing in the substrate industry, there is an increased burden for ink manufacturers as material quality gets worse to match the pricing of developing nations.”
A Proper Balance
Original UV ink sets lacked flexibility and second generation UV LED ink sets incorporated this, which enabled UV to be used on flexible as well as rigid substrates. For UV ink to gain in flexibility, the question is does it have to lose in both durability and adhesion? Perhaps an ink developer’s highest goal is to achieve the magic combination of all three.
Customers don’t want to choose between a “hard” or “soft” ink, according to Mark Swanzy, COO, Xanté Corporation. “They want a ‘one-for-all’ hybrid ink with the best characteristics of both ink types. Current ink technologies allow customers to print on a myriad of substrates with a single hybrid ink, which was unavailable until recently.”
“A proper UV ink formulation balances adhesion and durability along with flexibility. It is possible to achieve adhesion, durability, and meet end use requirements on flexible as well as rigid materials. The tradeoff is that digital print equipment does not permit ink to be easily changed. Therefore, as ink formulators we have to balance adhesion to a variety of rigid and flexible materials. So, we must work to achieve the best results across a broad set of requirements. That is why it is essential to work closely with the printer, the equipment, and material suppliers to optimize this balance as much as possible,” admits Amerine.
Larry D’Amico, sales director, NA, Durst Image Technology US, LLC, cautions that “as inks evolve they are developed to handle a wider base of applications, but there are still inherent limits. As inks get more flexible they tend to adhere to a wider variety of substrates, but become softer and more apt to block or scratch. This sliding scale will always exist and requires the need for customers to determine the ink characteristics that best fit their needs.”
According to Paar, ink design is always an exercise in compromise. “If the elasticity of an ink is increased, its surface hardness is therefore decreased, thereby reducing chemical and mechanical resistance. If its flow rate is increased before its dot gain ceases, it becomes increasingly matte in appearance and loses optical density and the addressable color space shrinks. No change happens in one characteristic of an ink without affecting other aspects,” he cautions.
In the future, Hutcheson believes UV ink will continue to evolve, with more focus on dedicated applications and substrates, for example highly flexible applications, corrugated media, porous and non-porous media, and textiles.
Searching for More
UV ink, particularly UV LED ink, continues to influence and be influenced by substrate and application introductions. As more print providers search for ways to offer everything with one device and one ink, it is apparent that UV ink sets are one of the few ways to do so. Ink chemists, manufacturers, and suppliers band together to create new ink sets that build on the positive qualities original UV ink brought to the table several years ago.
Sep2019, Digital Output
