As digital printing expands into the corrugated market, inks are being called upon to do a lot more than just improve appearance of the package or the point of purchase display. As is the case in all packaging printing, inks have to meet a wide range of requirements, including sustainability and regulatory mandates.

For example, Randy Paar, marketing manager – display graphics, large format solutions for Canon Solutions America, noted that inks should have a good color gamut, white ink for providing a base on kraft liners to maintain realistic colors and skin tones, etc., low odor, and a pleasing finish.

Jim Wegemer, director of national accounts for INX International Ink Co., said that aside from performing well on the printer, digital inks for corrugated need to be able to withstand post-print processing in the converting operation.

“The sheets will be cut and formed at some point, and the inks need to be able to go through these processes successfully. Inks cannot scuff, mark or chip in a die cutter, and they require a good degree of flexibility. Digital inks need to be stable over time, perhaps with a shelf life between six to12 months,” Wegemer added.

Wegemer also noted that meeting regulatory requirements are essential.

“Corrugated packaging must meet end-customer needs, which in some cases means the inks should be formulated with materials that comply with government regulations such as Swiss Ordinance,” Wegemer noted. “You also want digital printed packaging to be recyclable, so the inks should not detract from this. As with other print formats, digital inks should provide good value as a part of the total cost to print.”

Adi Shorer, HP PWI corrugated, product manager, post-print, observed that printers are looking for more than just color from their inks.

“We are finding that many corrugated converters are looking for a health and safety certification to meet brands’ demands for production of corrugated boxes, while addressing sustainability targets,” Shorer said. “Inks must therefore not only be of high-quality with vivid colors but must also contribute to ensuring converters remain sustainable across their entire ecosystem.

“HP’s solutions are helping brands to do this,” added Shorer. “For example, HP’s true water-based inks are designed to meet worldwide regulatory requirements and to address a broad range of health and environmental considerations throughout the entire lifecycle of print, from production to disposal.

“Furthermore, HP PageWide corrugated printing technology meets stringent industry guidelines for the Safe Use of Printing Inks to provide safety requirements in accordance with global regulatory and industry guidance, including Swiss Ordinance, Nestlé Guidance, FDA, and EU Framework among others,” he added. “HP PageWide true water-based inks are uniquely certified for stringent UL EcoLogo. This 3rd party certification indicates that HP’s inks were tested by UL to comply with stringent requirements, and meet a range of multi-attribute, lifecycle-based criteria related to human health and environmental considerations.”

Evandro Matteucci, VP and GM, packaging and building materials, EFI Inkjet, spoke about the benefits of white ink.

“One significant advantage in ink that we pioneered for corrugated is the availability of a superior-quality, highly opaque white ink,” said Matteucci. “Used under color inks, it gives converters that ability to produce brighter, high-impact color imaging on brown kraft board. Plus, used on its own on brown kraft board, it lends an attractive, sustainable look that is very popular today in packaging designs.

“The color quality our inks provide is of critical importance,” Matteucci added. “Much of the work Nozomi printers produce are high-graphics shelf ready packaging or retail POP displays. Our customers need to be able to deliver consistent, repeatable and accurate color while providing the color impact that drives product sell-through in retail locations. Additional ink colors beyond CMYK available for EFI Nozomi give packaging converters the ability to match up to 97% of the Pantone Color gamut. EFI Nozomi inks are also certified for repulpability and recyclability by the Western Michigan University Recycling, Paper and Coating Pilot Plant.”