Aqueous Printers: Still Relevant After All These Years

Aqueous printers have been around since the dawn of the wide-format industry. But they are still as relevant as they ever were. Two big reasons are the ongoing technological developments that have allowed the technology to remain viable, and the emergence of durable aqueous printers.

“Aqueous is proven technology for indoor applications, and is the number one choice for print-on-demand end users and in-house print service shops,” said Tim Check, product manager, Professional Imaging, with Epson America. “For applications where viewing distances can be slight, aqueous can deliver prints with detail, clarity and sharpness, free of distracting image artifacts.”

Let us examine some of the advancements contributing to the amazing staying power of aqueous, and explore what may be ahead for the technology.

Tried-and-true aqueous printers still provide a reliable and cost-effective means of producing wide-format prints, Erik Norman, president of Kitchener, ON, Canada-based RTI Digital, reported. And with improvements in media coating science, a wider range of suitable applications is becoming reality.

The more notable developments of the last several years have centered around the growth of latex printers, most notably those from HP, which have revolutionized aqueous and extended its capability, Norman said.

“The pressure for low-entry points and environmentally-friendly printers will help keep the traditional water-based printer market vibrant,” he predicted.

As inkjet print technology continues to evolve, the basic premise of the inkjet technology remains the same. That premise is the direct placement of droplets of ink onto the surface of a print medium, Check said.

Choosing the right print technology for the job can save time, money and frustration, he adds. Aqueous inkjet technology, while a mature technology, is also one of the most versatile. It offers very high image quality, ease of use, low equipment costs and little need for maintenance. The applications best suited for the technology include photography, fine art, proofing, CAD/technical, indoor graphics, office documents and even screen film positives. With an extensive range of media products available, many other applications can be printed using the same aqueous inkjet printer, but at a potentially higher cost for the media.

Aqueous ink formulation improvements have led to expanded color gamut, richer blacks with better D-max, and instant dry qualities, he added.

Aqueous-based pigment inks provide exceptional color stability, high resistance to ozone and UV light for long-term fade resistance, and high smudge and water resistance. With these qualities, aqueous pigment inks are finding increased use in short-term outdoor applications.

Five to seven years ago, printing large-format was both intimidating and challenging, added Rich Reamer, director of product marketing, Large-Format Solutions Division, with Canon USA in Melville, NY. “Now they’re like your home printer, very easy to use,” he said. “With it becoming so easy to print, we see more in-house uses, in supermarkets, and in elementary education. They can create signage for hallways and classrooms.

“When you look at the construction market, a general contractor once would hand out printouts to all subcontractors. Today, the general contractor hands out CDs, and subcontractors print out their own plans.

“The reprographic shops that used to print those plans have seen business fall off, and now sell those printers to the subcontractors.”

Oriol Gasch, director, Americas Large Format Printing for HP, agrees with Norman about ease-of-use and reliability gains made in aqueous printers.

For instance, he said, since its launch in 2006, HP Scalable Printing Technology (SPT) has evolved and supported continuous advancement in the capabilities and performance of HP’s inkjet print systems, and new generations of HP Designjet printers. Recent advances in SPT print head design, fabrication and materials technologies have enabled HP engineers to develop a print head that is designed to last the life of HP Designjet T120 and T520 ePrinters.

“Eliminating print head replacements means improved printing economy and ease of use for users,” Gasch reported.                 

More recently, HP unveiled PageWide Technology, featuring more than 40,000 tiny nozzles on a stationary print head that spans the width of a page, to deliver four colors of original HP pigment ink onto a moving sheet of paper. “Because the paper moves and the print head doesn’t, printers are quiet and dependable, offering laser-fast print speeds and a rapid first page out,” he said. 

Gasch summed up by noting print head, ink and print technology innovations are delivering high levels of reliability, print quality and productivity. The printers offer low product acquisition costs, have low energy consumption and, in the case of HP PageWide, produce color pages at up to twice the speed and up to half the printing cost compared with LED/toner based LF printers, he said.

Durable Aqueous Printers

The emergence of durable aqueous printers has had a profound impact on the market. For starters, durable aqueous has eroded the traditional solvent market share by delivering high-quality, vibrant, cost-effective output that’s far more environmentally friendly than solvent inks. “They use a lot of heat, so energy [use] remains high, but you lose all the harsh chemicals,” Norman said.

Latex printers enable aqueous technology to extend into a wider application range suitable for outdoor durability, he adds.

Under HP’s leadership, Norman said, this category has grown markedly in the last several years. “We see alternatives to latex also emerging, such as resin-based inks that even offer a wider substrate range and require less output energy, enabling durable aqueous to be used for rigid substrate printing applications, and which may start to encroach into the UV curable market.”

While a coating or lamination process was once necessary, media is now available that offers greater waterproofing and UV protection. “So now you have water-based inks whose durability has been extended by the media,” he said.

The media improvements are making possible limited outdoor applications, such as short-term event marketing, backlit films and window signage suitable for short-term promotions like weekly store sales.

Gasch seconds that sentiment. “Durable aqueous technologies, like HP Latex printing technology, can now produce high-quality images on a broad range of coated and uncoated media, including PVC banner, self-adhesive vinyl, PET films, paper, wall coverings and textiles,” he said. “This gives print service operators many versatile print applications to offer to customers, including retail and outdoor advertising, event and exhibition graphics, vehicle graphics and interior decoration. The HP Latex water-based formula involves an ink vehicle, water and pigments, ensuring high-quality prints that also meet customers’ environmental needs for indoor displays and wall coverings.”

The HP Latex ink vehicle is the colorless, liquid component of the inks. It provides reliable, consistent drop ejection and carries the ink’s solid components to the surface of the print, controlling how ink and media interact, Gasch said.

“The physical and chemical properties of the ink vehicle are critical both for drop ejection performance and control of ink-media interactions,” he reported.

“These properties are obtained by formulating the ink vehicle with a combination of water, humectants and wetting agents, and liquid additives. In HP Latex printers, the ink vehicle is evaporated by heaters to produce a dry and ready-to-use print right out of the printer. Water provides the high surface tension, low viscosity and energetic vapor bubble that are ideal for use in HP Thermal Inkjet print heads. Inside each drop generator a vapor bubble—lasting only about 10 microseconds—drives a drop of ink out of a nozzle with the repeatable volume and velocity required for reliable, high-quality printing.”

Finally, he added, pigments are used to produce color. Unlike dyes, which are dissolved in the ink vehicle, pigment particles must form a stable suspension to prevent settling during ink storage and use. The pigments used in HP Latex Inks are anionic, meaning they have a negative surface charge. This promotes a stable particle suspension because particles with like electrical charges repel each other to prevent them from sticking together. More recently, an anti-scratch agent has been added to HP 881 Latex Inks. This material lubricates the surface of the print to resist penetration by sharp objects that could damage the ink layer and does not affect ability to laminate the print or weld prints together.

“With durable aqueous inks, customers can print the same applications they would with alternative inks like hard, eco-solvent or UV, without the need to use expensive coated materials, and with all the benefits of environmentally-friendly inks and printing systems,” Gasch pointed out.

Another impact of durable aqueous printers has been a decrease in larger-sized prints, Reamer remarks. The print shops that once had 60-inch aqueous printers have shifted to 44 inches. “Where we’ve seen the uptick is in the photo and fine art market,” he said. “The canvas wrap business has been expanding, and the sale of the canvas media has grown. Photographers start with smaller printers, and realize they want to print bigger and bigger.”

The 44-inch has been exceptionally successful in the photo market, where many individual photographers have moved to the 60-inch printers. Reamer and colleagues have seen the 60-inch increasingly embraced by photo labs, as well by companies across the country like Canvas On Demand, which takes prints sent online by customers, prints them on canvas and ships them back.

Memjet Head Printers

Memjet technology has set the tone for single-pass inkjet printing being the future in both the technical and graphics markets, Norman said. It delivers a quality and productivity blend unmatched by traditional “swathing” inkjet printers.

“Memjet-powered printers, such as our Vortex 4200, use an aqueous ink that requires no heat for drying. They thus have a very small energy footprint, making them among the most environmentally-friendly printers in the market.”

With the right media choices, which are expanding rapidly, the technology enables both indoor and outdoor applications, such as short-term event marketing, Norman said. Memjet’s photo-quality dye inks have a great color gamut and vibrancy.

When coupled with powerful tools like Caldera GrandRip+, he added, “you’re hard-pressed to find more bright and beautiful prints within the aqueous inkjet range. Memjet technology has been one of the most disruptive print technologies in years, and the technology advancements are just getting started.

“As with many new disruptive technologies, adoption takes a while, but then a tipping point occurs. I believe we’re nearing the tipping point for Memjet-enabled printers, and that the age of single-pass printing is upon us.”

Due to the speed of the Memjet technology, the printers can now be used for unique applications such as specialty gift wrapping for little Johnny’s birthday gift, or for maritime mapping. “Because of the Vortex 4200’s speed and productivity, it can now enter applications once limited to offset,” Norman said.

Memjet print head technology used in the Oce ColorWave 900 offers PSPs or in-plant locations an array of applications that when compared to current digital color printing technologies yield improved productivity and turn-around time and lowered cost of operation. So said Sal Sheikh, vice president of marketing, LFS, for Canon Solutions America.

“For short-term signage such as point-of-purchase posters, PSPs do not have to choose between traditional slow digital large-format devices or costly set-up associated with offset printers,” Sheikh said. “Consequently, this technology enables PSPs to respond more quickly to their customers by offering additional value and application capabilities to quickly turn around jobs in a fraction of the time it would previously take at a competitive cost of operation.”

For color technical documents required by the architecture, engineering and construction segments, PSPs can now do mixed black-and-white and color print sets without sacrificing productivity, or move to full color sets, he said.

“However, we are just seeing the beginning of this trend,” he added.

“As we continue to move toward critical mass with this technology, we will see the benefit of quick-turn, cost-competitive wide-format color cascade throughout the entire value chain in several segments.”

Check takes a different view of Memjet technology.

He acknowledges it has grabbed attention with its ability to turn out a huge volume of color prints, and that the technology is well suited for producing office documents. “However, when viewing high-coverage graphics and photographic prints close up, there are noticeable banding artifacts from high-speed paper feed stepping and nozzle degradation,” he said. In comparison, non-Memjet printers run about one-tenth the speed, but deliver higher-quality output on a wider array of media, at about 1/25th, or four percent of the price, he said.

The Future

Norman is among those who envision aqueous printers’ capabilities being extended still further in the years to come. He pegs that conviction to the continuing development of durable aqueous inks such as latex, and the adoption of single-pass printing technologies that enable marketplace disruption.

“You have durable aqueous inks extending the application rage into apps formerly limited to solvents or UV printers,” he said.

“And you have the single-pass technology allowing aqueous printing to be an adjunct to offset, enabling more short-run production and output versioning.”

Check is also upbeat on the future prospects for aqueous. There is a bright future for aqueous technology as research and development efforts continue to advance inks, print heads and media support systems,” he said.