By Melissa Donovan
Water-based ink sets were at the inception of digital printing. Ink chemists push the envelope constantly to introduce new products that advance the print process with efficiencies in production as well as better the environment. Enter latex—or resin—ink.
When HP Inc. coined the term “latex ink” and introduced this technology at drupa in 2008, it was met with great interest—and perhaps skepticism. Was this the future of wide format digital print? After gaining mainstream recognition in the following years, it was clear latex was here to stay and other competitors entered the field.
Today latex ink or as many of HP’s competitors refer to it—resin ink—is a prevalent player in wide format. Analyst firm I.T. Strategies’ report published in the 2024 August issue of Digital Output states that “combined, eco-solvent and latex account for almost half of vendor revenue share of the wide format graphics print market, making it the largest revenue segment.”
Above: With HP Latex ink, end users realize the full benefits of sustainability—water-based ink, user-installable printheads, odorless printing, instantly dry prints with no outgassing needed, and no warning labels on the ink cartridges.
Overwhelming Advantage
Latex/resin ink offers a host of advantages for those print service providers (PSPs) committed to working with the technology. Media versatility, fast dry times, and environmental benefits top the list.
A large selection of media can be printed on using these inks. “For a sign shop that does a lot of different types of work, the media options for printing with latex are wide,” notes Joshua Gill, senior manager, Brother International Corp.
Brother’s latex ink offers a high color depth and excellent print result on a range of materials, including PVC, paper, canvas, as well as wallpaper.
“As long as the media’s thickness is compatible with the printer, it can be used, making this a highly versatile solution for print shops with limited equipment or those seeking an all-in-one printing option,” states David Lopez, product manager, professional imaging, Epson America, Inc.
Various applications benefit from being created with the help of latex/resin ink sets. HP Latex inks, for example, are able to print onto paper, self-adhesive vinyl, wallcoverings, and many specialty substrates.
“Latex technology is great for production runs of many different applications. One of the big advantages of latex technology is that the output is ready for installation, lamination, or shipping as soon as the printing is completed—there’s no need for outgassing time,” shares Daniel Valade, product manager of digital print, Roland DGA Corporation.
Lopez points out that “as an aqueous-based ink, resin requires no off gassing, allowing prints to be ready for immediate lamination. This can save print shops anywhere from six to 24 hours of drying time compared to solvent inks, significantly speeding up production workflows.”
Since latex/resin inks are water based, they tote an environmental advantage. “Using a water-based chemistry such as HP Latex also ensures an end-to-end sustainable offering—from disposable printheads and maintenance supplies to the UL ECOLOGO and UL GREENGUARD certifications,” explains Thomas Giglio, large format segment lead, North America, HP.
“Sustainability is quickly becoming the cornerstone of the innovations we’re seeing in the market. New and reformulated materials making use of recycled components, eco-friendly packaging, and ‘green’ production processes can now be combined with water-based, eco-friendly latex inks to reach ever-expanding markets and applications,” adds Gill.
Overcoming Initial Setbacks
Latex/resin ink wasn’t always as accommodating. Like any new technology, it had its challenges.
One of the initial issues involved “the amount of heat needed to evaporate the vehicle and cure the resin component of the HP Latex ink,” according to Giglio.
Four generations of HP Latex ink later—this issue is solved. “It has allowed for considerable reduction in the amount of heat needed, thus increasing our customers’ application reach while still delivering the highest image quality,” shares Giglio.
With these high levels of heat, “the temperature associated with thermal printhead and ink technologies created initial challenges on various substrates resulting in limited media and application uses,” explains Gill.
“Some of the initial challenges with latex printing were related to media compatibility. Latex inks and the optimizer require a significant amount of heat to cure, which can have an adverse effect on some materials, however, media manufacturers have come a long way in the last five years. Now, there is a much wider range of materials available that are compatible with latex inks,” says Valade.
Latex/resin ink require an optimizer to be printed first, and then the ink is applied on top, this also presented difficulties early on in development. “The optimizer and ink cannot mix outside of the printed image, and if they mix beforehand, they can bond and ruin the printhead,” explains Lopez.
When developing the SureColor R-Series, Epson engineered a way to ensure the optimizer and ink stay separate prior to the printing process, including a redesigned MicroPiezo printhead, replaceable fabric wiping system, and maintenance flushing pads to clean the printhead prior to printing.
Continued Development
Challenges still exist, and manufacturers constantly revamp ink chemistries and hardware to address—and potentially—solve them.
Speed, quality, and performance are three areas that Gill says still seek improvement. “Brother has pushed the envelope in color with the gamut of its latex resin inks, then built a dedicated printhead with which to deliver it all on an environmentally friendly platform. The demands of the market will likely not move far off the aforementioned parameters but Brother continues to work toward besting every iteration of our solutions,” admits Gill.
Color gamut is top of mind, more specifically increasing the color gamut without adding extra color channels. “While many of our competitors use extra colors like red, orange, and green, our continual ink chemistry development has allowed us to innovate higher pigment loads and deliver an enhanced gamut while only using six colors,” explains Giglio.
White ink continues to be of interest. “More users are starting to ask for white ink technology as a way to expand their product offerings,” notes Valade.
HP Latex white ink is an on demand white ink solution. Giglio explains that HP end users can remove the white printheads from the printer when not in use, which eliminates both costly maintenance and waste—this is typically associated with white ink.
Maintaining a quality print throughout the drying process is something Lopez says is an ongoing challenge. “Resin is a water-based ink and requires a drying process to evaporate the water and leave the pigment to bond with the substrate. Print shops need to be aware different materials require different levels of heat for a successful drying process. If a post-heater temperature is too high it can cause a wave in the substrate or possibly scorch the material. Identifying the appropriate heat level for the substrate being used is critical to ensure high-quality output,” he suggests.
To address this, Epson incorporated a three-tiered heating system—a pre-, platen-, and post-heater—into the SureColor R-Series printers. “This system promotes even drying by allowing the water evaporation process to happen prior to the print reaching the post-heater, so by the time the print reaches the post-heater, most of the drying is complete, reducing the risk of heat damage,” explains Lopez.
Competitive Spirit
Latex/resin ink is advantageous for the PSP looking for a one-stop shop when it comes to its equipment. The fast drying times, no outgassing, and media versatility allow for multiple applications to be printed and subsequently created from a latex/resin-based wide format printer.
HP was at the forefront of this innovation, but Brother, Epson, and Roland are now part of the fray with technologies of their own. And I think we can agree, versatility in product, as well as competition is certainly a good thing.
Dec2024, Digital Output
