By Digital Output Staff
Digitally printed textiles are found in a number of different environments, from stage backdrops to customized apparel.
Two processes are used to digitally print onto textiles—direct and transfer. In one, ink is laid directly onto the fabric. The other process involves the fabric accepting a transfer of a graphic. This graphic is printed on transfer paper, and then the transfer paper is laid on top of the fabric, run through a heat press, sublimated, and the graphic is bonded to the fabric.
While transfer printing is a preferred choice for print service providers (PSPs) because of the wider color gamut, durability, and washability, direct printing also offers benefits. Print providers who do not have heat press capabilities in house or want to save money and time by eliminating transfer paper gravitate toward direct printing onto fabric since this means less steps in production and even a cost savings in some aspects.
Specifics play into which type of fabric is ideal for direct print, whether dye-sublimation (dye-sub) or inkjet. Ink and textile type are two factors. Media manufacturers recognizing the demand for materials in this segment focus on offering products featuring durability and visual appeal, while simultaneously considering the fabric’s end use.
Less Steps, Cost Effective
PSPs interested in adding fabric printing to the mix, but aren’t looking to commit a lot of capital find direct to print an ideal option because the process involves so little steps. The cost of entering into this segment is lower than in the past as well.
Eric Tischer, president, Verseidag US, argues that while those PSPs who offer transfer printing don’t intend to switch to direct print, direct printing offers both production and application advantages. “With regards to production, a transfer paper isn’t needed with direct, which is a cost savings. With regards to products and print quality, there are applications such as backlit and flag printing, where direct print offers better product saturation due to the production process,” he continues.
Part of the growth is because direct printing of textiles is becoming more cost effective. “Due to the entrance of industrial machines the gap between rotary screen and direct textile printing has narrowed to the point that direct is now an economical option. In the past, the speed of printing and cost of inks were both a deterrent to direct printing. Now the print speed and ink cost have made direct digital an ideal alternative for textile production,” explains Ann Sawchak, owner, Expand Systems, LLC.
“With the cost of direct to print machinery becoming more competitive, and the increasing variety of coated fabrics available, direct to print becomes an ever-growing, viable option,” agrees Jeff Sanders, digital fabric sales manager, Pacific Coast Fabrics.
Joseph M. Rooney, North American sales manager, Heytex, believes that while direct print is growing, it stills falls behind where it should be and this can be remedied by increasing PSPs’ education on, “how they can use the same 3.2- or five-meter UV, latex, or solvent printer and achieve brilliant results. This education process is the most important part of direct print versus traditional dye-sub.”
The Right Ink
Printing directly to textiles can happen either with dye-sub or traditional inkjet inks. In both scenarios, a coating is typically included on the fabric prior to printing to optimize print quality and provide a softer hand.
Dye-sub ink sets used in the direct process include direct disperse, acid, reactive, and pigments with and without binders, according to Expand Systems. A pre-treatment or coating is generally required for all of these options.
Laura Wilson, West coast print media specialist, Dazian, LLC, says coatings for dye-sub direct have come a long way, which helps explain why direct to print fabrics are gaining in popularity. “In the past, the treatments were heavier and tended to affect the look and feel of the fabric and they were not as soft and drapey as typical dye-sub fabrics.”
With traditional inkjet technologies, like aqueous, solvent, eco-solvent, UV, or latex, Gautier Peers, territory sales manager, Dickson Coatings USA, explains that certain fabrics require an inkjet lacquer or coating to guarantee the right penetration of solvent and eco-solvent inks, as well as optimum fixation of UV and latex inks.
“Aqueous, eco-solvent, solvent, and UV inks require an inkjet receptive coating in order for the inks to adhere to the surface of the fabric and not soak into the fabric, which mutes the colors. While this coating offers bright, vibrant colors, it typically reduces the soft hand of the fabric, making it more rigid and less flexible,” adds Jessica Blevins, product specialist, S-One Holdings Corporation.
Despite direct print not requiring a heat press to transfer the graphic from paper to fabric like in transfer printing, some ink sets do require a post-treatment after printing to ensure the ink is embedded into the fabric. Fixation of the inks to the material generally occurs with heat or steam.
For fabrics printed with acid, reactive, or direct disperse dye, in the direct dye-sub process, a steam post-treatment is required. Direct disperse dye, and pigments with or without binders, can also be post-treated with dry heat, based on Expand Systems’ research.
According to Lily Hunter, product manager, textiles and consumables, Roland DGA Corporation, if UV inks are used, no extra fixation is needed. “UV inks are cured by the printer’s lamps and the topcoat on the media, in combination with the heat generated during the printing process, this allows the ink to ‘bite’ into the media.”
In addition, solvent and latex inks do not require any fixation either, points out Mark Shaneyfelt, director – sales and marketing, print media, Aurora Specialty Textiles Group, Inc.
Coatings Expand Range
Most vendors agree that woven substrates are ideal for direct printing, but coating advancements have led to more fabrics to be printed to directly.
As Tischer advises, the most ideal fabrics for direct print are those with an ink receptive top coating. Without it, he says inks are forced to wick out and image clarity and quality can be reduced.
“A fabric that is not coated properly is subject to issues that can include ink migration, hot spots, and overall discoloration when exposed to the elements,” agrees Sanders.
Coatings aside, Michael Katz, president, Jacquard InkJet Fabric Systems, believes any fabric construction can be printed on. “Construction has little influence except the image will look different on each fabric. For example, the image will be noticeably different on an open weave fabric compared to a tight, dense weave.”
“Any woven or knit substrate, including blends; and technical fabrics are ideal for direct printing,” according to Dr. Jerry Pinto, president/CEO, Advanced Chemical Solutions, LLC.
Hunter says textiles that are stiffer and have dimensional stability are generally better for direct to print than stretchy materials.
“Polyester is best constructed for the direct to print process because it features a tight weave and smooth surface,” explain Tamara Pitman, product manager, and Kristina Devine, senior marketing and pricing specialist, Coveris Advanced Coatings.
Angela Mohni, director of product marketing, SEAL, part of ACCO Brands, says that since direct to print fabric is generally created by a weaving process, it can yield minor defects in a roll of material. She cautions that while this is to be expected occasionally, PSPs shouldn’t assume there is something wrong with the fabric.
It is a combination of the correct ink and material that dictates the best possible fabric for the job. Sharon Roland, advertising and PR manager, Fisher Textiles, admits there is not a one-size-fits-all fabric solution for the direct to print process. “The type of fabric best suited is totally dependent on the ink system as well as the final application.”
For dye-sub, Expand Systems recommends acid dye be used with nylon, silk, and wool. Reactive dye should be used with cotton, rayon, and silk. Disperse dye is ideal for polyester. Pigments with and without binders are used for most fabrics, including blends.
Alternatively, Blevins says latex inks offer the most versatility, working with cotton, canvas, polyester, cotton/polyester blends, textile wallcoverings, silk, and nylon.
Characteristics in Demand
Print providers and their customers demand brilliant color, a soft hand, durability, and options from direct to print fabric providers. While many of these features are common across all applications, some properties hold more importance than others depending on end use.
“Vibrant color that is repeatable is a demand. Users want the color of their fabric to be just as vibrant as if they were printing to paper or vinyl,” explains Mohni.
Softness and drapeability are also important, she continues. “Customers choose textiles due to their soft hand and ability to evoke a different type of reaction from the final consumer of the graphic. Textiles also give a higher end feel and are very effective in marketing high-end products such as cosmetics, fragrances, and electronics.”
“It is important that the material is durable so that it can be folded and no creases show when unfolded,” point out Pitman and Devine.
Wilson believes a common request among PSPs is a wider variety of material options. “Luckily, there are fantastic direct to print fabrics available with bright white points and excellent feel that image very well.”
Arguably, demand depends on the final end use of the fabric. Roland admits that while longevity, durability, flame retardancy, wrinkle resistant properties, and soft hand are almost always a consideration, the importance of one over the other varies from job to job.
For example, Sawchak says the fashion apparel market is especially sensitive to color matching and color gamut, whereas lightfastness is an important attribute for outdoor furnishings, signage, and flags.
“Depending on the specific market segment, a number of needed characteristics will always come into play,” agrees Tischer. “For instance in the silicone edge graphics market—which is growing rapidly for retail, exhibition, and décor—vibrant, soft, and wrinkle-free fabrics are the norm.”
Blevins cites cleanability as being in high demand in the décor market, specifically addressing indoor upholstery, window, and furniture solutions. “While many direct to print fabrics offer more longevity outdoors in comparison to traditional dye-sub, the fabrics cannot be washed and cleaned like dye-sub prints. Direct print fabrics are not suitable for apparel or upholstery fabric that requires more than just a spot cleaning,” she adds.
Awareness of Challenges
Despite advancements in coatings, ink technologies, and fabric construction, there are still challenges that PSPs should be aware of when it comes to printing directly to textiles. For the newly inundated, there is a bit of risk involved. It is important to correctly pair media and ink and understand the fixation process.
“When printing directly to fabric, test for ink and fabric compatibility. Also, if fixation is required, be aware that there will be a longer learning curve, as you’ll need to get familiar with the equipment involved and the process in general,” recommends Hunter.
“It is crucial that each and every fabric is carefully profiled and that temperature settings are exact for heat fixation. If fabrics are all treated the same, issues relating to oversaturation can result in color migration or color not developing fully or evenly. Heavier fabrics require different heat fixation settings than a lighter fabric,” suggests Sanders.
“There are some issues with ink migration if the fixation process is not done correctly. This is the source of either ink bleeding or actual dirty marks that can be seen above in backlit applications such as light boxes,” shares Blaise Humphries, business unit manager, Decoprint, SENFA.
Besides compatibility and fixation, PSPs should know that media handling is a bit different. “Direct print is not the same as traditional dye-sub and therefore requires slightly more attention to detail when it comes to shipping, handling, and installing the material. With direct print, the material can be easier to scratch, wrinkle, or crease,” explains Rooney.
As with any project, fabric or not, consider the final end use. “There are challenges in choosing the right fabric for the end application. It is vital to know all of the requirements of the finished application, such as flame retardancy standards, durability, and wrinkle resistance, before taking on the job,” advises Roland.
A Direct Approach
Textiles designed for direct to print processes—whether dye-sub or inkjet—must meet a number of expectations. Coatings and ink sets work together to expand the variety of textiles used for direct print.
As digitally printed textiles’ popularity grows, so too does direct to print. Print providers and their customers demand products that cater to their every application need, from traditional soft signage to performance apparel and home furnishings.
Jul2016, Digital Output