Direct-to-object printing is a terrific opportunity for printers, but it isn’t easy. Inkjet printers and inks have progressed so much that irregular shapes, including cans, tubes and more can be digitally printed on. Direct-to-object printing has come a long way.

One key challenge has been adhesion.

“With the UV flatbed printer’s ability to print on just about any type product, adhesion is the biggest challenge,” said Jay Roberts, Roland DGA product manager - UV printers. “Ensuring that the graphics will ‘stick’ to any surface is crucial. Adhesion promoters, which are not new to any industry, have become necessary for direct-to-object printing. Roland’s UV printers can be configured with Primer (CMYK + Primer, Gloss and White), which also helps satisfy many of the needs for adhesion.

“Promoters are key for optimum adhesion, especially when it comes to certain non-traditional substrates/objects,” added Roberts. “Our ‘on-board Primer’ option also increases adhesion when printing on materials that can present challenges, like acrylic and plastic.  The Primer option makes prepping a non-traditional substrate or object before printing full-color graphics quick and easy.”

Jay Larsen, GM and director of R&D – digital hardware for INX International Ink Co., said ink adhesion and durability is always the first item that needs to be qualified with a direct-to-object printing project.

“This initial testing will determine the correct recipe for ink formulation and laydown, surface treatment, cure type, and cycle and post-print coatings,” Larsen said. “The primary challenge is the test platform must be able to accurately mimic the printing, curing and other parts of the recipe that will exist in the final printer.

“The second major challenge is print quality,” added Larsen. “Many direct-to-shape projects require very fast printing cycle times which dictate a single-pass printing method to meet the speed requirements. With single- pass printing, substrate surface tension and consistency is required for good print quality. However, this may require a change in the upstream process in order to optimize and control the printing surface quality.”

Warren Catchpole, director, digital solutions for digital inkjet inks at Wikoff Color, said the major hurdle in direct-to-object printing is adhesion.

“Metals and glass are difficult to adhere to and some end-users do not want to be bothered with pyrosol, corona or flame treatments,” said Catchpole. “Some of the more industrial applications can bring other requirements as well, for example oil resistance, water/wash resistance and abrasion resistance. This is why working with the correct ink partner is key to finding the all-in-one solution application.”

“There can be a couple of challenges in direct-to-object printing,” said Matt McCausland, senior product manager, Professional Imaging, Epson America. “Usually the initial investment is pretty high, operators need a higher level of technical expertise, and some knowledge is needed for ink adhesion, depending on the substrates that are being printed on.

“Because of this, Epson designed the SureColor V7000 with ease-of-use in mind,” added McCausland. “The Epson UV flatbed printer offers several usability features, including a pin registration system for quick loading and easy media alignment, a multi-zone vacuum system to keep materials securely in place, and automatic thickness adjustment to instantly accommodate media up to 3.14-inches thick.

“In addition, many UV and direct-to-substrate printers require customers to select a specific ink for either rigid or semi-flexible materials,” noted McCausland. “The Epson SureColor V7000 UV flatbed printer leverages a semi-flexible ink, UltraChrome UV, so customers aren’t limited to one type of output. It was essential to us that we provide customers with an all-around, work on everything type of ink for increased versatility.”

Phil Jackman, global product manager, digital, Sun Chemical, said that in addition to adhesion and resistance properties, the main ink challenge for direct to object printing is achieving optimum jetting performance leading to good image quality.

“This is because these objects are often irregular shapes and thus the throw distance of the drops is farther than many other digital applications because it is not possible to get the printheads any closer,” said Jackman. “The print speed of some applications also induces turbulence which exacerbates the importance of good jetting and drop placement accuracy. Inks utilizing high performance pigment dispersions are required in these demanding situations. The manufacturing and dispersion of pigments is a core competence of Sun Chemical and we continue to develop these materials specifically for our inkjet applications.”

“Major challenges for UV inkjet direct-to-object printing include a precisely tuned surface chemistry of the ink in order to accomplish the correct ink flow when printing on rotating objects as well as high flexibility and product compliance, especially when printing drinking cups or bottles,” said Matthieu Carni, director Business Unit Inkjet at Siegwerk.

Merav Sheffer, marketing manager, Velox Ltd., noted that unlike flat printing, direct-to-shape printing is done when the container is spinning/rotating at high speed.

“This is a challenge since it requires high accuracy and consistency in decoration throughout tens of thousands of decorated containers. In addition, each color is applied separately, and colors are limited by the number of color stations on the decoration system. Since no color should touch another color, designs are also limited,” Sheffer said.

“In direct-to-shape digital printing, accuracy and consistency are even more challenging as the decoration is done without physically touching the surface,” Sheffer added. “Velox’s robust system architecture technology (ADA Technology) provides high-speed and accurate delivery of the ink to the container surface. But this is one side of the equation. Special ink formulation is the other. Velox developed a dedicated ink chemistry, its Variable Viscosity Ink (VVI) Technology for direct-to-shape applications that allows per-pixel drop shape control. By controlling the drop shape Velox ensures high print quality together with ink efficiency. On the regulatory and compliance aspect, digital direct-to-shape printing must meet the common strict industry standards, from health and safety aspects as well as functionality. Velox’s ink technology ensures superb functional properties as adhesion, scratch resistance, low migration and others.

“Velox’s system includes 14 process colors achieving extremely wide color gamut and accurate color matching covering over 95% of the Pantone plus color book. As a result, there are no color limitations and any number of colors can be used freely per design as well as smooth gradients from any color to the other,” Sheffer noted.

“Moving from an analog process to a fully digital one can be overwhelming when advised by vendors who do not understand this thoroughly,” said Oscar Granados, director of sales at LogoJET. “We have met many customers who transitioned to digital and suffered a lot because the vendor didn’t advise them about the process changes they would encounter. Partnering with the right vendor is key to have a great customer experience and smooth transition.”

“As customers work to distinguish their brands while reducing waste, we are seeing massive changes to packaging shapes and materials,” said Enric Odena Garcia, category marketing manager, Markem-Imaje Centre of Competencies. “And we’ve mentioned already that the regulatory environment is a significant challenge for our customers, and we continually work together with them and our R&D team to respond to the changing needs. Another trend is the move towards customization. This creates challenges developing the right solution, controlling risk for the customer and at the same time limiting the number of products in our portfolio to a manageable level to maintain the highest standards.”