Digital textile printing is a specialized form of roll-to-roll wide-format inkjet printing. Printers built exclusively to feed rolls of fabrics are replacing some rotary and flat-screen printing equipment traditionally used for industrial textile printing.
Unlike the textile dye sublimation process, which is limited to polyester and poly/blend fabrics, digital textile printers eject tiny droplets of ink directly onto many types of non-stretch natural and synthetic textiles. The types of inks, pre-treatments, and post-treatment processes used depend on the specific type of fabric being decorated and how it will be used.
Manufacturers of apparel and decor fabrics regard digital textile printing as a promising way to reduce the water and energy consumption, waste, and water pollution associated with traditional textile dyeing and printing. Some experts estimate that digital fabric printing can reduce water use by up to 90% and electrical usage by up to 30%.
Types of Printers
Unlike “direct-to-garment” printers that decorate pre-sewn apparel products, digital textile printing equipment prints on rolls of fabrics that will be cut and sewn into a variety of products.
Depending on the type of fabric, a single roll of printed fabric could be used to make different types and sizes of shirts, dresses, slacks, shorts and fashion accessories or home textiles such as pillowcases, sheets, tablecloths, duvets, upholstery, or drapes.
Multi-pass industrial direct-to-textile printers use clusters of moving (“scanning”) printheads that travel back and forth across the width of the substrate Makers of multi-pass direct-to-textile printers include Durst, EFI, Epson, Mimaki, Mutoh, SGPrints, DGI, and Kornit Digital.
Epson has actively promoted the benefits of digital textile printing to the fashion industry. This video demonstrates features of their Monna Lisa Tre series of direct-to-textile printers. (Video: Epson Monna Lisa Tre)
Single-pass industrial textile printers use stationery arrays of printheads that span the width of the substrate. All ink is applied in a single pass as the substrate travels beneath the fixed printheads. On a single-pass printer, fabrics can be printed at speeds of up to 295 linear feet per minute.
This video shows how fast fabrics move through the EFI Reggiani Bolt single-pass textile printer. (Video: EFI Reggiani BOLT at at glance)
EFI’s Reggiani Bolt, the MS LaRio, SGPrints’ PIKE and Konica Minolta Nassenger SP-1 are single-pass inkjet printers for high-speed, high-volume production of printed textiles (e.g. up to 20 million linear meters a year).
Types of Inks
Different combinations of inks, pretreatments, and fixation processes are used with different types of synthetic and natural fabrics. The pretreatments, ink formulations, and post-treatment processes help the ink colors penetrate the fabric and resist fading, dirt, and repeated wash cycles.
Direct-Disperse Inks are used to printing directly onto polyester and polyester blends. These inks actually dye the fibers of the fabric and become part of the textile. A post-print heat process is required.
Acid dyes are used on pretreated nylon and silk fabrics. The printed textiles then must be steamed to set the inks and washed to remove any residue. Post-print heat processing is used to permanently set the dye.
Reactive inks for linen, rayon, nylon create a chemical bond with the cellulose fibers in these fabrics. The printed textiles must be steamed to fix the inks and washed to remove any residues.
Textile pigment inks include binders that enable the pigments to adhere to the surface of cotton and other natural fabrics. A rotary heat calendar is used to fix the pigments to the fabric.
Advances in pigment inks are enabling textile printers are enabling apparel manufacturers to skip the post-print steaming and washing processes to reduce water and energy consumption.
The Kornit Allegro printer was the first direct-to-textile printer that used pigment inks to eliminate the need for steaming and washing. (Video: Kornit Introduces Allegro & Cut)
Most printers can use up to 7 or 8 colors of inks.to maximize the range of colors that can be reproduced.
Pre-Treatments and Post-Treatments
Before printing, fabrics must be cleaned and pre-treated. The pre-treatments help fix the dye in the ink to the fibers in the textile, control the spread of ink droplets, optimize the intensity of the colors, and support ink absorption for faster dry times.
After the fabric absorbs the ink, it must be dried and/or coated to keep the inks from rubbing or washing off. Some printed fabrics must be washed to remove any residues from the ink.
Companies such as EFI, Durst, and Kornit have developed in-line systems for handling all of the pre-treatment and post-treatment steps a fabric might require without having to unload the printed rolls of fabric and take it to another finishing station.
The Durst Alpha Series of textile printers has an integrated washing system and inline treatment and drying units. (Video: Durst Alpha Series - Innovation for Digital Textile Printing)
With the right combination of inks and pretreatments, a wide variety of off-the-shelf natural and synthetic fabrics can be digitally printed. The pretreatment is applied to the cleaned fabric immediately before the fabric is printed.
Printing fabrics for human use is different than printing fabric banners. Fabrics for use in apparel or home furnishings must meet specific standards for durability and safety. For example, fabrics used to make pillowcases shouldn’t contain any chemicals that would cause harm if inhaled by a sleeper. Chemicals that can cause skin reactions must also be avoided
Oeko-Tex testing certifies that finished fabrics are free from harmful chemicals and safe for human use. GOTS (the Global Organic Textile Standard) defines how organic fibers should be processed into finished textiles to meet ecological and social criteria.
The ability to make and sell garments on-demand has attracted a number of aspiring fashion designers. So software developers have made it easier for them to design textiles, specify colors, and view how the printed pattern would look on a sewn garment.
EFI’s Optitex software includes 2D and 3D visualization tools that enable designers to see how their designs will appear positioned on the pieces to be sewn into the finished garment. (Video: EFI Textile Ecosystem )
Adobe has introduced a Textile Designer plug into Photoshop. Many designers already use Photoshop when starting fabric designs. Adobe Textile Designer enables designers to build and preview repeating patterns, defining separations, work with colorways and keep every element editable in Photoshop until the design is ready to print.
Adobe Textile Designer can be used in conjunction with a Datacolor ColorReader PRO device to help designers measure color inspiration in the real world and transfer the color specification data wirelessly to Photoshop.
X-Rite has also developed more advanced color-management tools to reduce the amount of fabric wasted by printing inconsistent or inaccurate colors.
Advances in Technology
Manufacturers of digital textile printers have developed apparel “micro-factories” that enable brands and fashion start-up companies to consolidate and streamline the process of designing and converting printed textiles into ready-to-sell garments.
This video shows how the EFI Textile Printing Ecosystem enables apparel manufacturers to build a start-to-finish system of making small batches of garments as needed. (Video: EFI Textile Ecosystem)
On-demand or just-in-time garment and textile production are revolutionizing the apparel industry because it reduces the risk that clothing manufacturers will be stuck with excess inventory that must be shipped to a landfill. When on-demand garment production occurs in micro-factories close to the location where the garments will be used, it significantly reduces the environmental impact of shipping garments from mass-production textile factories in Asia and Europe.
To quickly gain a better understanding of the requirements of the fashion and textile industry, some printer manufacturers of direct-to-textile printing systems have acquired European companies that have made textile inks, printing, steaming, and washing equipment for years.
EFI acquired the Reggiani textile equipment manufacturer and Optitex, a leading supplier of design and pattern-making software. Epson acquired the Fratelli Robustelli company that manufactured textile printing equipment and the For. Tex company that specialized in formulating pretreatments and selling textile inks.
SGPrints, a manufacturer of rotary screen-printing presses, has used their long-time knowledge of the textile industry to develop their own line of direct-to-textile inkjet printing systems.
At the 2019 ITMA textile technology show, dozens of innovations were announced to further improve the efficiency and sustainability of textile design and printing.
For example, Kornit Digital introduced the Presto, a direct-to-fabric printer that uses new NeoPigment Robusto pigment inks to eliminate the need for pre- and post-treatment of fabric and allows for high-quality printing on a broad variety of fabric types.
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This post is part of a series we are publishing to help you understand the many types of analog and digital printing processes now in use.
Follow Ordant on LinkedIn, Facebook, or Twitter to learn when the next post in this series has been published. Our next post will discuss direct-to-garment printing.
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Digital Press Technology-Part 1: Electrophotography
Digital Press Technology - Part 2: Production Inkjet Printing
Wide-Format Inking Printing - Part 1: Roll-to-Roll Printers
Wide-Format Inkjet Printing - Part 2: Flatbed & Hybrid Printer
Wide-Format Inkjet Technology- Part 3: Grand Format Printers
Inkjet Sublimation Printing- Part 1: Textiles and Soft Signage
What is Inkjet Dye Sublimation- Part 2: Rigid Panels and Hard Surfaces