The Ever-Changing World of Ink for Digital Printing

Superior Solvent Ink

The wonderful world of ink has undergone major changes in the past few years. We’ve seen the introduction of ultraviolet curable inks. Solvent inks are now readily available as mild solvents. And environmentally friendly inks that allow sign makers to print on just about any substrate are broadening the industry’s capabilities.

These ink breakthroughs are the fruit of ink manufacturers research and development (R&D) efforts ­ and this is just the beginning. Ink and printer manufacturers are working together to discover solutions to pending problems ­ such as the need for greater speed ­ and methods to enhance reliability, among other initiatives.

“We are going to see a lot of research in the future. There is discussion about whether or not UV ink capability will replace solvent-based ink capability. The consensus is that it will happen. It’s just a matter of when,” says Xerox digital imaging spokesperson Sandra Mauceli. “The hardware for UV inks is expensive, but the cost will come down.”

Investing in Tomorrow’s Inks 
Indeed, printer companies, materials manufacturers and ink producers alike have a vested interest in seeing new and improved inks flood the market with their new colors and better performance. These stakeholders are investing significant dollars to see that happen.

Maria Bragg, marketing development manager of 3M Commercial Graphics, says 3M makes substantial investments in ink development as it relates to understanding the interplay between the printer technology, the ink and the printable substrates.

“Ink manufacturers are continually developing new inks in response to the changing market needs, such as changes in printers, print heads, substrates, environmental needs and application requirements,” Bragg says. “Ink jet printer inks today are considerably different than those of five years ago.”

Raster CEO Rak Kumar says his company works with multibillion-dollar ink companies to develop inks for its printers. Raster plays the role of a systems developer to make sure the ink meets its criteria. This effort is 10 percent of the printer manufacturer’s R&D budget.

“As we learn from customer feedback and new chemistry or new print heads become available the inks improve. For example, the requirements for the ink chemistry to work with very fine drops for a high dpi printer are very different than the requirements for a low dpi low-resolution printer. As new print heads become available, inks have to change,” Kumar says.

Pat Ryan, general manager of Seiko-I Infotech Americas Business Unit, says his company makes an ongoing and substantial investment in ink development. “Our goal is to develop different types of ink, ones that surpass the current generation of ink for speed, color durability, environmental and health concerns, and various other issues,” he explains.

The Ever-Changing World of Ink
For all of the reasons our resident experts mentioned, ink is an ever-changing world. All of this R&D has led to noteworthy changes in inks over the years, including the introduction and industry acceptance of solvent-based inks.

Unlike water-based inks, these inks use highly volatile chemicals and are designed for printing on plastics and other non-porous substrates. After printing, the solvent dissipates and leaves only the dry ink film on the substrate. Solvent-based inks have changed the market in a couple of ways, Ryan explains.

“Solvent-based inks allow you to print directly on un-coated media. That alone lowers the cost per print because it allows digital prints to go places they could never go before thanks to the pigment in solvent inks. The radical change to uncoated media also allows greater outdoor durability. So digital imaging is replacing traditional processes, like screen printing, for vinyl signs and banners,” Ryan says.

A big shift is the move toward UV inks. Another significant change has seen a shift toward eco-solvents. Eco-solvents are practically odor-free and do not require special ventilation or environmental equipment. Currently, eco-solvents are available in six colors: cyan, magenta, yellow, black, light cyan and light magenta. These inks are far less aggressive than their full solvent counterparts, yet these inks are becoming more popular and major printer manufacturers are catering to the demand with new machines.

Braggs notes still other changes: “Light colors have been added to improve image quality. More pigments are available for use in ink jet inks, leading to some discussion of spot color systems. White inks have recently been introduced. Ink has always been critical in the production of high quality graphics, and will continue to be. The need for inks designed to meet specific needs may be increasing.”

Why Do We Need More Inks? 
Ink has come a long way, baby. But now that we have every color we could hope for, including metallics; now that we have eco-solvents; now that we have UV inks, what more could the industry possible want? Faster inks for one, Ryan repeats, even greater durability is another. Then there’s compatibility with a wider range of media types and the quest for even more environmentally friendly inks.

“There is always a price issue. People want cheaper inks. There are a lot of ways to develop ink. You can develop an cheap ink or you can develop ink that performs better,” Ryan says. “There’s a lot of work left to be done in order to meet all those needs and sell ink for a dollar a gallon that looks great and lasts.”

As customers move into new applications, Kumar says inks need to be available in different colors, such as spot and white, with different adhesion characteristics, greater flexibility to resist cracking, environmentally safer, and improved jettability to enhance reliability. That means multiplied millions more dollars with go into researching and developing new and improved inks for the future.

In addition to the traditional CMYK, 3M’s Bragg says more inks are needed to improve the apparent resolution, increase the color gamut and boost productivity. These are common themes in ink R&D today.

“As marketplace needs evolve there is often a need to develop new inks to meet those needs,” she concludes. “Ink development will continue the parallel the evolution of large format printing technology and end-user application requirements.”

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