By Melissa Donovan
Print service providers (PSPs) have options when it comes to which ink set to employ in their shop. They can commit to just one, and enjoy the benefits that it brings, or employ multiple types to satisfy customer demand.
Aqueous, latex/resin, solvent, and UV are the four main categories of ink we discuss in this year’s state of ink feature. Each is explored in terms of usage percentage worldwide, popular applications, and why a PSP prefers it over its counterparts.
Additionally, ink packaging and white ink is addressed. How ink is packaged is changing. The physical material of the containers as well as the amount of ink found in them are designed in response to the popularity of bulk packaging options as well as to meet sustainability goals. White ink continues as a specialty trend due to continued challenges in its chemistry. New formulations offer stability.
Above: Using the Mutoh XpertJet 1462UF UV LED flatbed printer and Mutoh UV inks, its possible to create raised, tactile effects.
Aqueous Ink
Aqueous inks are the first segment to review, but note we are not covering aqueous-based textile inks. For a deep dive into ink for textiles, visit here for our feature, Intense, Stable Color.
Simon Daplyn, product and marketing manager, Sun Chemical, believes there is a trend towards aqueous solutions, in part due to legislation on materials use and the perception of their increased sustainability benefits.
Aqueous inks are mainly used to print to paper due to the low cost of capital equipment and high quality of printing, according to Pedro J. Martinez, CEO, AFFORD. “While they were big 20 years ago, they are now in the minority, with maybe five to ten percent of the existing market at the moment in print shops.”
“Print providers prefer aqueous inks to other inks mainly because aqueous inks are environmentally benign, odorless, and regulatory compliance is easier,” shares Nitin Goswamy, president, A.T. Inks.
Other reasons printers choose aqueous inks are because they “tend to—but don’t always—have lower hazard labelling and can be easier for operators to handle. There is also minimal odor. The thin ink film can concentrate the pigment and increase vibrancy. They also offer good light stability and water fastness,” adds Daplyn.
Latex/Resin Ink
Latex/resin ink sets are water based, but due to the addition of resin we categorize separately.
“Latex/resin is added into aqueous inks to improve the durability of the prints as well as enhance adhesion of aqueous inks on non-porous substrates and bolster weather resistance. Additional advantages with latex/resin are improvements in dot gain, improved gloss, and better edge acuity,” shares Goswamy.
Compared to other segments, Martinez estimates in developed markets that latex accounts for approximately 25 to 30 percent of the market share. He also sees this increasing with new additions to the market segment.
Environmental considerations make latex/resin advantageous. “A pivotal factor in latex/resin market adoption has been its water-based formulation, making it a preferred choice for companies aiming to minimize their environmental impact. The aqueous nature of resin ink eliminates volatile organic compound (VOC) emissions and unpleasant odors,” shares David Lopez, product manager, Professional Imaging, Epson America Inc.
Another reason PSPs prefer latex/resin to other ink sets is the combination of dry time and durability. “In many applications they can avoid lamination or can laminate shortly after printing, which for many users is an advantage,” suggests Martinez.
“There is no outgassing with these inks, eliminating the need for waiting periods before laminating. This immediacy in workflow is a significant advantage, allowing for faster job completion,” agrees Patrick Donigain, senior manager, marketing, Canon U.S.A., Inc.
Latex/resin presents media versatility, which in turn means many applications benefit from these ink sets. “Its primary use cases include vinyl for printing vehicle wraps, canvas signage applications, and most traditional roll-to-roll based signage output. Given its ability to accommodate a range of media, resin can be used in additional cases such as textiles—natural fibers such as cotton—as well as uncoated canvas and papers, which is not possible with solvent ink,” adds Lopez.
“These inks are used for printing wallpapers and murals due to their low odor, environmental friendliness, and the ability to adhere well to different substrates,” suggests Sohil Singh, VP, StratoJet USA.
Paul Edwards, VP of the digital division, INX International Ink Co., agrees. “Essentially, print quality, decent adhesion range, low odor characteristics, and selling it as an eco-friendly alternative makes latex/resin ink popular in many wide format applications.”
Solvent Ink
This includes true solvent options, as well as eco and mild solvent.
Tony Simmering, eco-solvent and dye-sublimation product manager, Mutoh America, Inc., argues that eco-solvent printing is the backbone of traditional print shops. “The ink has higher outdoor durability than UV LED and enhanced/stable color output compared to other solutions like latex and is also easy to work with after print.”
“You cannot ignore solvent printing because it maintains a substantial market share. The variety of non-porous substrates and media that work with solvent, the cost of print, the vibrancy of the colors produced, the option of double-sided printing, the ease of drying, and its decent to good weatherability are a combination that can’t currently be replicated by other print segments,” admits Goswamy.
Solvent and by association eco-solvent ink is used about 35 to 40 percent in the occidental world, suggests Martinez. He says new formulations free of dangerous ingredients/chemicals make for valid reasons to continue using this technology, mainly because the inks offer good adhesion, light fastness, and are economical.
Solvent and eco-solvent inks work with a range of materials, which means a number of applications are printed using the consumables.
“Any sticker, sign, or poster that is produced on flexible media like paper, PVC, or a prepared substrate can be printed with eco-solvent. It is specially advisable for car wrapping and other highly demanding applications,” admits Martinez.
Solvent inks are known for their excellent outdoor durability and weather resistance, adds Singh. As such, “print providers serving outdoor signage and graphics markets may prefer solvent inks for their longevity in challenging environmental conditions. They can withstand exposure to UV radiation, harsh weather conditions, and other environmental elements without significant degradation.”
Lopez says a key selling factor of solvent ink is its achievable color gamut, which is expansive. “This makes it easy for customers to reproduce hard-to-create colors, including oranges and reds, and makes it possible to adhere to precise branding color.” With an expansive color gamut, solvent-based printers are used in giclee, proofing, and packaging prototypes.
PSPs prefer solvent because they “appreciate the fast drying, color vibrancy, and high durability of the inks in a range of applications and substrates,” summarizes Daplyn.
UV Ink
UV, UV-curable, UV LED, and UVgel all fall under this category of ink.
“UV inks are currently about 30 percent of the market but are trending up as more equipment and ink sets are made available. Shops entering new markets that rely heavily on UV inks such as promotional items and braille can bring UV inks by necessity,” shares Ken Parsley, UV product manager, Mutoh.
According to Goswamy, “various market studies have put the use of UV inks in wide format between 30 to 40 percent in mature markets—balance is aqueous, latex, and eco-solvent—and in developing markets between five and ten percent—balance solvent, latex, aqueous, and eco-solvent.”
Donigain looks at usage based on print width. “In the 64-inch space, UV printing constitutes a minority share, but it is gaining ground. In the 3.2-meter segment, UV printers dominate and handle the majority of printing tasks. Despite positioning itself differently from traditional UV, UVgel is making strides in the 64-inch space.”
Growth is a sure thing. “With UV inks 100 percent solid and not having any VOCs, this environmental advantage, together with their ability to provide adhesion on almost any type of substrate allow this segment of the market to experience growth over the next few years,” predicts Martinez.
PSPs prefer UV ink “due to its instant-drying properties. It forms a polymeric thin film on the surface of the substrate, which results in a very tough and durable print. The instant drying can also enable a faster print speed, increasing overall output,” adds Daplyn.
“Traditionally UV inks were used on hard substrates like PVC, other rigid plastics, and metals. However, with the advent of flexible and hybrid inks, UV is used for all types of applications. UV inks offer compatibility to an array of substrates as diverse as glass, acrylic, coroplast, MDF, wood, HDF, paper, PVC, leather, and banners,” shares Goswamy.
Lopez lists primary applications for UV ink like rigid signage, real estate signage, and in-ground posters using corrugated plastics, PVC, and acrylic; as well as promotional items like pens, golf balls, and cell phone covers.
With UV ink providing the ability to build up ink to a tactile level, braille signage is growing in popularity in terms of applications used, notes Parsley.
Another application is heat transfer films. Donigain notes that the largest volume user of Canon UVgel specializes in heat transfer films. “The flexibility of our inks, offering both matte and gloss, broadens application possibilities.”
The movement from traditional arc or mercury lamps to UV LED lamps contributes to popularity. “Print shops may shift towards UV LED systems for their energy efficiency, reduced heat output, and the ability to cure a broader range of heat-sensitive materials,” says Singh.
Pack Up
Ink packaging is important. Regardless of ink type, the container must be sealed well, if not the properties of the ink will change. Once a design achieves this goal, it’s not redesigned very frequently—however ink packaging has recently been influenced by environmental efforts as well as safety and health concerns.
“The containers often depend on the system and whether ink packs can be attached directly to the printer rather than poured into a feed tank. Some cartridge use has moved to pouches where it is easier to maintain the degassing of the ink. Other trends point towards lighter weight and more recyclable packs with items such as bag-in-box packs rather than hard-walled bottles,” explains Daplyn.
Goswamy admits that with sustainability becoming more mainstream, as well as many printers now having containers that fit snugly in the printer, there are some changes in ink packaging.
Epson shifted from traditional ink cartridges to ink bags over the last few years. “The ink bags reduce plastic usage and are more space efficient when compared to their cartridge counterparts. Ink bags store flat, are easier to dispose, and contribute to a more sustainable printing practice,” says Lopez.
Bags hold more ink, creating a bulk scenario. “Cost efficiency and the desire to streamline procurement processes drive the adoption of bulk packaging. It can contribute to cost savings—especially for high-volume print shops—and minimize the frequency of reordering,” suggests Singh.
“Mylar bags are popular because they adapt to different systems. They reduce the amount of plastic that ends up in landfills from cartridges,” shares Parsley.
Maintaining White
Undergoing years of research and development, today’s white ink is much more manageable than some of the first iterations.
Inks with low viscosity are where challenges remain. “Recirculating printheads have improved the reliability of white inks as compared to non-recirculating printheads. However, solutions are limited for printheads that use low-viscosity inks. Low viscosity limits the ability of the ink formulator to provide print quality along with jetting reliability,” shares Goswamy.
“White pigments need to be larger in size than colored pigments to contribute to the ink’s hiding power, requiring careful management of the stability of the low-viscosity ink,” adds Daplyn.
According to Singh, new formulations of white latex/resin ink include stabilizers and additives, which help maintain the stability of pigment particles, reducing the likelihood of clogs.
According to Edwards, UV white ink features a higher viscosity target due to the printhead technology. “This higher viscosity not only allows for greater stability of the pigment in the ink, but it also has a high pigment load that provides more opaque white inks.”
“Due to the slight higher viscosity of the white UV inkjet inks, inks can be kept with very little maintenance today,” admits Martinez.
Minimal maintenance refers to the ink being constantly in motion either through recirculation or agitation. “UV white ink still requires a continuously stirred sub-tank and recirculation between main and sub-tanks to prevent settling,” explains Goswamy.
At Canon, the UVgel white ink offers a notable advantage in regards to cleaning, says Donigain. “The gel-based ink does not evaporate, as the formulation—particularly in handling titanium dioxide particles in white ink—ensures a slower settling process, reducing constant agitation to prevent settling.”
Sediment settling can lead to potential issues like nozzle clogs and printhead failure. In response, white ink circulation systems are found in UV printers like Epson’s. “This system ensures that every 30 minutes, white ink circulates through the lines, preventing sedimentation buildup. This continuous movement helps to ‘shake’ the ink and reduces issues associated with static white ink,” says Lopez.
Ink for Any Job
Ink chemists continue to develop solutions that meet market demands. A true focus is on quicker dry times, while still yielding a quality result. Each type of ink offers a variation of these goals, but is dependent on materials printed to and their environment. There is an ink out there for any job—it all depends on what you choose.
Apr24, Digital Output
