By Industrial Print magazine Staff
Many objects are printable using sublimation techniques—both direct and transfer dye-sublimation (dye-sub). In addition to fabric, rigid or hard surfaces are decorated with this technology. Dye-sub transfer is favored for rigid substrates. In this instance, the graphic is printed onto sublimation paper and then transferred onto blanks like mugs, coasters, or metal pieces for artwork. Dye-sub for rigid materials is advantageous for print service providers (PSPs) in terms of cost, quality, and flexibility, despite a growing interest in printing directly to objects using other methods of digital printing.
A Polyester Requirement
Many types of rigid materials benefit from dye-sub transfer printing. Most—if not all—must feature a polyester coating or have a polyester exterior. There are endless options and because of this there is no limit to the kind of customer who might consider buying a dye-sub transfer printed piece.
Specifically, Lily Hunter, senior product manager, Roland DGA Corporation, explains that any object with a polyester coating able to withstand 400 degrees Fahrenheit for a period of time—60 seconds to minutes—without warping can be used for dye-sub. A white surface is preferred, but metallic or light-colored surfaces work well too.
“Any material that can handle dye-sub temperatures and either be polyester or coated with polyester can be dye-sublimated,” shares Randy Anderson, product marketing manager, Mutoh America, Inc. Popular items range from coffee cups to jewelry, and new blanks designed just for this printing process are constantly released.
Dye-sub transfer works for flat, curved, and irregular shape items with a polyester exterior or coating. Tim Check, senior product manager, Epson, notes that while there are many dye-sub, print-ready materials available on the market, for those PSPs printing to unique products, it is possible to coat them in a liquid clear polyester resin for compatibility.
Industries interested in dye-sublimated rigid pieces include universities and teams, commercial hospitality for interior décor, art galleries and independent artists for printing paintings and photographs, decorative gift markets sold through ecommerce sites like Etsy, and corporations and businesses for branding and promotion, notes Victoria Nelson Harris, senior textile segment specialist, Mimaki USA, Inc.
“Creating promotional products attracts businesses and customers from all industries who may be interested in promoting their brand on client giveaway items such as face masks, mugs and drinkware, key chains, ceramic ornaments, awards and plaques, and mousepads and name badges,” comments Randy Peters, president/CEO, The Mosaica Group.
Home décor is also a popular segment. “It has been printing dye-sub metal panels for many years now. Dye-sub benefits this application as the print quality is very high and the colors are vibrant. The printers are resistant to scratching and damage, much more than a UV-curable print on similar material for the most part,” says Mike Syverson, textile manager – North America, Durst Image Technology US, LLC.
“Polyester-coated sheets of metal, wood, and MDF provide print shops with opportunities to create custom home/office wall decorations, signage, and specialty products such as tabletops. Printed ceramic tiles represent another popular dye-sub printing application. The rich color and appearance of dye-sub printed materials provides designers with unique ways to enhance living and office spaces,” adds John Ingraham, senior product marketing specialist – dye-sub, Canon Solutions America.
Not to Be Overlooked
For PSPs already familiar with dye-sub transfer printing fabrics, the press for rigid substrates or objects/blanks isn’t much different. However, there are a few subtle nuances that shouldn’t be overlooked. These involve the transfer paper, printer settings, and heat transfer equipment as well as the actual act of transfer. Variable times and temperatures depend on the product the graphic is set to.
According to Marco Girola, marketing manager, JK Group, transfer paper plays a crucial role in the printing results. “In paper choice, you must consider—its ink absorption capacity, the drying speed, the stability, the release capacity, and the working capacity with the high-speed machine.”
Transfer paper for rigid surfaces should be heavier than one used for fabric and include a specialty coating designed for use with a rigid substrate. “The hard surface of the substrate is not as forgiving as a soft, textured fabric surface. Any coating residues on paper can transfer over to the rigid substrate, leaving a hazy, cloudy look,” notes Hunter.
“Rigid material printing typically works with a 105 gsm paper or greater without tack. Since dye-sub printed rigid materials tend to produce sharper print results compared to fabrics, the higher basis weight reduces cockle and other printing artifacts that may be visible in the final printed graphic. Another point is that metal expands when heated while paper contracts and as a result the transferred image can become distorted. Heavier basis weight transfer paper helps to minimize this issue,” recommends Ingraham.
According to Anderson, the transfer paper used should also feature some gas permeability. “With rigid substrates, this ability of the paper to allow vapor to pass through greatly reduces ghosting and blowouts. In some cases, a layer of fabric is used on top of the paper to help facilitate this release of vapor.”
A major difference is in the printer settings. “Fabrics consist of round fibers, which may include stretchable materials that are knitted or woven together to create a print canvas. The print settings are adjusted to increase the amount of ink applied so that the top and sides of fabric are covered. Print resolution is limited by the weave of the fabric, which allows the printer to operate faster. In contrast, the rigid materials are able to hold detail and can visually take advantage of the printer’s higher resolution modes. Little ink is needed as only the top surface will be colored,” explains Check.
Hunter suggests using a printer profile created for rigid substrates that includes higher resolution and more print passes. “With some fabrics, you can get great results printing at three-pass, 540×360 dpi, but that’s not the case with rigid substrates. When printing to rigid materials, you need at least 720×720 dpi.”
When a graphic is transferred to fabric it is fused to a fiber versus a graphic transferred to a polyester coated hard substrate. As such, the finishing equipment—or heat transfer equipment—may differ depending on the object being decorated. Harris provides the example of using jigs for sublimation on a traditional heat press or specialty mug heat presses and ovens that affix the ink after printing.
“Time and temperature varies depending on the size and type of material used. Ball park range for polyester coated products is around 380 to 400 degrees Fahrenheit for one to three minutes,” she adds.
Syverson provides the example of dye-sub compatible ceramic tile requiring 90 to 120 seconds of contact time at 380 degrees Fahrenheit, meanwhile a wood panel may need less time and more temperature.
Printers of all shapes and sizes, equipped with UV LED ink, are saturating the marketplace with the message that literally anything can be printed to directly. If this is the case, where does dye-sub transfer printing specifically for rigid substrates or hard surfaces stand? Well, it is still advantageous for a number of reasons.
Peters believes the primary benefit of transfer printing is quality. “Coatings on transfer papers are designed to keep the ink droplet on the surface of the paper, allowing for less ink to be used during the transfer process, thus saving customers money in the amount of ink needed to get their desired results. Overall, transfer printing produces better resolution, more vibrant colors, and crisper details.”
“Transfer dye-sub printing is advantageous,” agrees Hunter. “Specifically for transferring to rigid substrates, the smooth transfer paper produces photorealistic prints with very fine details.”
Combine fine detail with excellent color reproducibility and this why dye-sub transfer is popular in fine art and photography, adds Harris.
Check points to safety and durability as main reasons dye-sub printing reigns supreme as the printing method of rigid products. “The sublimation process is unlike other printing methods in that the ink becomes part of the material and is below the surface. Sublimated rigid products can easily be cleaned without risk of the image fading. Rigid products like coffee mugs and water bottles will be in direct contact with a person’s mouth and the liquid they consume. With the inks below the surface of the material, it prevents the inks from interacting with the liquid, as well as prevents the coffee from staining the mug.”
Another safety-related advantage involves cleaning. “The surface of dye-sub rigid substrates is easily cleaned and sanitized, which is beneficial for hanging graphics in medical facilities, hotels, and offices,” advises Ingraham.
Dye-sub’s efficiency is also important, according to Girola. This is possible thanks to an optimized process. Paper can be printed in advance and stocked, requiring a small space and assuring better time to market.
Check points out that a typical mug only costs pennies to print. “There are also speed benefits as the sublimation process is two steps—printing transfer paper and heat transferring to the rigid item. The printer can run quickly, without consideration for the heat transfer process. High production companies balance the number of heat transfer presses with one to few printers for maximum production throughput. The result—lower production costs, which may translate to savings for the end user.”
“Transfer dye-sub gives you the most flexibility as the array of rigid products is quite diverse, from flat metal panels to non-flat objects such as a ceramic mug or baseball cap,” shares Syverson.
Dye-sub transfer to rigid materials involves multiple trends. There are benefits to offering the service, especially if dye-sub transfer to fabric is an existing offering in house.
Dye-sublimated hard surfaces are starting to include wall décor using metal, acrylic, and glass in art galleries, museums, photography studios, healthcare facilities, hotels, restaurants, offices, and homes, lists Peters.
Beyond high-end locales, customization on a consumer level continues to trend. “There is a shift to online shopping and growing demand for unique and personalized décor as people spend more time at home. Smaller companies are better positioned to compete with large established retailers as they are able to offer unique products and can sell through high-traffic online market places,” suggests Check.
“A newer trend and developing process for dye-sub printing uses vacuum presses, allowing three-dimensional (3D) objects to be personalized and customized as well. Literally fence posts, motorcycle helmets, and hockey masks are all being produced these days with dye-sub ink,” shares Peters.
This process involves printing onto transfer paper or transfer film, wrapping the object, and then placing it in a specialty 3D vacuum press, explains Hunter.
Other trends involve consumables. For example, transfer paper manufacturers are improving their coatings for better and shorter transfers. Additionally, substrates are being developed to last longer outdoors, says Hunter.
“Perhaps the biggest trend in rigid dye-sub, outside of new substrates, is extending outdoor performance. Some of this is a result of improvements in coating additives, but it is also coming from improved ink sets,” adds Anderson.
Not Hard to See Potential
Printing directly to premanufactured objects and rigid board is not going to disappear, if anything it will continue to grow. However, the dye-sub transfer process offers a different feel and appearance not necessarily achievable with direct to print. Sublimation transfer printing continues to be a viable option for PSPs looking to decorate rigid substrates and hard surfaces. It delivers photorealistic details and color reproducibility, which is why it is used for products found in home décor and hospitality to fine art and promotional.
Mar2021, Industrial Print Magazine