Fabric Printing: Transfer vs. Direct

Last month, we kicked off our four-part “fabric printing expert” series with a general overview of the market and technologies for fabric or textile printing.

This month, we’ll focus on two approaches to fabric printing: transfer-based dye-sublimation and direct-to-fabric. The latter involves both dye-sublimation as well as other types of dye and pigment inks.

Let’s sort it all out.

Dye hard

The story so far: a quick recap of how transfer based dye-sub works. The printer images on a special transfer paper that has a coating designed to hold and then later release the printed image. After printing, the paper is brought into contact with the fabric in a heat press, Under exposure to the appropriate combination of temperature, pressure, and time, the ink embedded in the paper is converted to a gas and penetrates directly into the fibers of the substrate. For chemical reasons, polyester fabrics are required for transfer dye-sub printing, although you can use dye-sublimation on other types of natural fabrics like cotton, but the results will vary.

A fast-growing variant of dye-sublimation printing is direct-to-fabric printing, which eliminates the need for transfer paper. However, this form of dye-sub still requires the output to be run through a heat press after printing to fix the dye on the fabric, and it also requires pretreated polyester fabrics. Historically, pretreated fabrics have been expensive and of lesser quality than fabrics used for transfer-based dye-sub, but both the quality and the cost are getting better.

Making a choice between transfer-based and direct-to-fabric dye-sub isn’t as easy as it may seem. It may sound desirable to be able to eliminate the expense and waste of having to use transfer paper, but there are other tradeoffs in going direct-to-fabric. A big one is the resultant image.

With direct-to-fabric dye-sublimation printing, the inks penetrate deeper into the fabric than those used in transfer printing – which only makes sense, since you’re jetting the ink directly onto the fabric rather than let a gas permeate into the polyester fibers. The result is often less vibrant color and “softer” text and images, plus more show-through on the reverse side of the fabric. As a result, the top application for direct-to-fabric right now is flags and other types of outdoor display graphics.

“The criteria that I use to help prospects analyze whether to go with transfer or direct-to-fabric is the end-user application and the type of fabric that is required based on the application,” says Tommy Martin, product manager, Textile & Apparel Business Development and Marketing, Mimaki USA.

At present, says Martin, popular direct-to-fabric applications are outdoor advertising like flags and banners; automotive and boating upholstery and seat covers; home furnishings and interior design such as bedding, drapes, upholstery, and outdoor seat covers; and technical textiles for hospitality, construction, and health care/medical markets. “All of these markets and applications require heavy density, high fastness, and durability and certain direct-to-fabric applications are best,” he says.

Since transfer-based dye-sublimation ink doesn’t penetrate as far into the fibers as direct-to-fabric, it also uses less ink. “You need less ink compared to direct-to-fabric,” says Paolo Rubini, a product engineer for EFI Reggiani, which demonstrated the new EFI FabriVu textile printers at last January’s EFI Connect, the company’s annual user conference. “There is a bit of absorption [with direct-to-fabric], but you need more ink to get the same colors. You also get better detail with paper compared to direct.”

A lot of development is going into direct-to-fabric dye-sublimation and new ink sets and machines will whittle away many of its limitations. This is one of those areas where the landscape will likely look very different in a year’s time, if not sooner.

Blurred lines

When we talk about direct-to-fabric printing, the lines can get a little blurred, since dye-sublimation is not the only ink technology that we run across. There are a number of other dye-based inks that are compatible with different kinds of fabrics. As textile printing gets more mainstream, these inks are beginning to appear in more commercial machines where once they were strictly the purview of high-end industrial textile printing equipment, An emerging trend is that one machine can handle all of these different ink sets, although not interchangeably.

These inks are:

• Reactive dye inks: Also known as “fiber-reactive dye inks,” these inks become physically part of natural cellulose fibers like cotton. 
• Acid dye inks: These inks react with the fibers in natural or synthetic polyamides like silk, wool, and nylon. 
• Pigment inks: Here is where a lot of the action in textile printing is starting to happen, certainly at the industrial end of the spectrum, and sooner rather than later at the commercial end. Generally, pigment inks can print on virtually any fabric, and cure via heat or UV radiation (these are not to be confused with the class of inks we usually refer to as “UV inks” found in flatbed printers). One hitch with pigment inks is that they require a bonding agent. Another is that, for a given quantity of ink, the more color (aka pigment) it contains, the less bonding agent, and thus the less wash-fast the print is. On the other hand, the more bonding agent, the more wash-fast, but the less vibrant or colorful. It’s a careful balance that needs to be struck.

An alternative to a bonding agent is a pretreatment. “Mimaki recommends pre-treatment, because it will produce the maximum color gamut possible,” says Martin. “Mimaki textile pigment inks include a nano-pigment agent, but we still recommend pre-treating to control the process.”

These non-dye-sublimation inks also require some kind of post-processing step, depending upon the fabric being used. “Reactive dye and acid dye inks require steam to set the inks,” says Martin. “Depending on the fabric, some will require washing and drying. Some – again, dependent on the fabric – require a drying method that steps down the temperature so that the fabric doesn’t stretch.”

The soft parade

There are a number of direct-to-fabric dye-sub printers on the market. Mutoh, for instance, recently released its new ValueJet 1938TX, a 75-inch direct-to-textile printer designed for customized fashion apparel, upholstery, interior decor, scarves, tradeshow graphics, soft signage, flags, sportswear and more. It features 8-channel piezo printhead technology and speeds up to 914 sq ft/hr, and can output onto various fabrics including closed, open non-stretch, face-in and face-out roll media.

Durst’s Rhotex and its new Alpha series include 1.9- and 3-meter units that print direct-to-fabric, and the Rhotex 180 TR is a transfer-paper based printer that has an optional direct-to kit. The sticking point with direct-to-fabric, as mentioned earlier, is that the materials typically require a pretreatment in order to perform optimally on press.

Mimaki has offered some variety of direct-to-fabric printers since the 1990s, and has been actively building out its line of DTF printers. Last year, the company launched the TX300P-1800, a 1.9-meter direct-to-fabric dye-sublimation printer. It supports all the ink sets mentioned above – dye-sublimation, reactive dye, acid dye, and pigment – although not interchangeably; it’s one fabric and one ink at a time. “You choose your ink at the time of order,” says Martin.

And 2016 and 2017 are seeing the first fruits of EFI’s acquisition of high-end textile printing equipment manufacturer Reggiani. This collaboration has led to the VUTEk FabriVU series of dye-sublimation machines, which ranges from the entry-level 1.8-meter FabriVU 180 up to the 5.2-meter FabriVU 520, the latter of which was launched last January at EFI Connect. The FabriVU line can also handle transfer-based dye-sub using the same ink set. “A lot of traditional display graphics printers can now enter into one of the hottest segments of the market, which is soft signage,” said Ken Hanulec, VP of marketing, EFI inkjet solution, in a press event at Connect.

The soul of the new machines

As digital textile printing continues to be a hot growth area, new machines, new fabrics, and new inks are removing many of the limitations of any given printing technology, especially in the direct-to-fabric category. Transfer-based dye-sub is still the go-to technology for the bulk of fabric printing – and its advantage is that it can print on substrates other than fabrics, such as coffee mugs and other 3D objects – but direct-to-fabric printing is developing rapidly. Stay tuned.

Textile Stories: Fashion & Digital Printing

This past February, elite artists from the fashion industry, celebrities, and socialites gathered at the IAC Building in New York’s Chelsea neighborhood to attend Epson’s Digital Couture Project – a one-of-a-kind fashion presentation that showcased the synergy between technology and fashion.

Held in advance of Fashion Week in New York City, the third annual Digital Couture Project was designed to provide a visual representation of how Epson’s digital printing technologies impact the fashion and textile industry. The fashion presentation, built around the theme of “Textile Stories,” showcased collections of 13 design teams from North and Latin America – all created using Epson’s textile printing solutions. The project showcased designs from featured collections of well-known designers including Lindsay Degen, Leonardo Mena, Ricardo Pava, Sarah Richards and others.

“Epson imaging technologies have empowered some of the world’s greatest artists to create spectacular creations – from flawless photo prints to priceless pieces hanging in museums, to now driving a new era of digital printing in the textile industry,” says Keith Kratzberg, president and CEO of Epson America. “This year’s Digital Couture Project pushed the limits of design, featuring looks from North and Latin American designers that could not have been created with traditional methods.” 

Prior to the event, Epson hosted a Fashion and Technology Forum, where Epson’s global president, Minoru Usui, outlined Epson’s continued vision for the role that digital technology will play in fashion. A panel of fashion and apparel industry experts discussed market trends and technology’s role in fashion.

For more information about the Epson Digital Couture Project, visit epson.com/nyfw.