Technology Focus: Aqueous, Durable Aqueous, Latex, and Resin Printers
At one time, the only consideration when looking at digital printing with water-based inks was whether it was dye- or pigment-based. And those two choices just meant the print would fade in days or months, certainly not years. Fast forward to today and the choices when looking at water-based ink are much broader and diverse. When deciding what printer or ink technology, remember it’s all about application, application, application.
When it comes to proofing or engineering drawings, most of the choices are pigment-based, though there are still dye-based inks being used for some applications. Proofing printers in many cases will add gamut expanding inks such as orange, green, or violet to cover as much of the Pantone library as possible for color-accurate proofs. Epson proofing printers certainly make up a large share of the market, and some of its proofing printers can hit 99% of the Pantone library. You can also find solid water-based printers from Canon and HP. Outdoor durability is very limited (months in certain environments with lamination), but that isn’t what these printers are designed to do.
A Look at Latex
The largest offering in aqueous inks for outdoor applications is latex, and HP is a big presence with its latex printers. I talked with Thomas Giglio, North American Latex Business Lead, HP Graphics Solutions Business to find out more about its latex product line. While the standard in large-format printing has been a progression from solvent, to mild solvent, to eco-solvent and UV-curable, the HP Latex is a water-based ink with the same or better durability.
Water makes up 66% of the composition of these inks, so there are no hazardous air pollutants (HAPs), which results in odorless prints. Also, because heat is used to evaporate the water from the ink during printing, and then cures the resin co-polymer (latex), the prints are ready for laminating and/or finishing immediately, as opposed to waiting for the other ink technologies to outgas — a process that can take a minimum of six to 24 hours (depending on the amount of ink on the substrate).
Two applications that are a great fit for latex is interior décor and vehicle graphics. For interior décor, most customers want eco-friendly graphics without odors that have some sustainability characteristics (such as UL Greenguard Gold or Leed certification). HP latex prints on a variety of wall graphics materials and soft signage durable textiles with a thin layer of ink that allows the characteristics of the substrate to be preserved through the ink.
For vehicle graphics, latex ink offers excellent density and elongation for surfaces such as compound curves. Wrap companies prefer latex because there is no outgassing to delay production, and the stretchability of the inks. If you have an install crew in the field (or the shop for that matter) and a panel is damaged, it is easy to re-print another and substitute it in, as you can laminate immediately and use it right away. HP latex inks are part of the 3M MCS and Avery ICS warranty programs.
Giglio shared that the HP latex graphics are durable up to three years unlaminated, and with the appropriate lamination, the warranties from 3M and Avery are up to seven years. The printhead technology is thermal and user-replaceable — printheads are less than $200 each. The printhead is 1,200x1,200 dpi with a 10-11 picoliter droplet. Typically, a printhead will jet approximately six to seven liters of ink before replacement, but that depends on the environment and frequency of printing.
Ray Weiss, Director of Digital Print Programs for PRINTING United Alliance, joined the Association in 2014. He assists association members with technical information on digital printing as well as digital equipment, materials, and vendor referrals. He oversees training and certification workshops at PRINTING United Alliance along with the Association’s Digital Equipment Evaluation program. Ray is project manager for both the PDAA Certification program and PRINTING United Alliance's Digital Color Professional Certification program and is an instructor for the Color Management Boot Camps. Ray regularly contributes to the Association's Journal and won the 2016 Swormstedt Award for Best in Class writing in the Digital Printing category. Outside of work, Ray enjoys biking, international cuisine and spending time with his three fantastic grandkids.