Fiber Optics: Matching Inks to Textiles
Textile printing. It’s everywhere at this year’s SGIA Expo, it seems. Industry analysts and pundits identify numerous opportunities in textile printing, but “textile printing” encompasses many different things and, indeed, many different technologies. The type of textiles you want to print will largely — but not entirely — determine what ink technology you will need. Just about any inkjet printing process can be used to print textiles, but the results you get will vary dramatically. Here’s a primer on textile printing technologies.
Direct-to-Garment: These are non-sublimation-based inkjet printers that print directly on T-shirts, tote bags, hats and other such items. These printers are compatible with cotton substrates, up to 50 percent blends. Vendors in this area include AnaJet (Booth 3419), Epson (Booth 1301) and Mutoh (Booth 2545).
Latex: “Latex” is a chemical term that refers to a “stable dispersion (emulsion) of polymer microparticles in an aqueous medium.” It’s not related to the natural latex exuded by plants or the synthetic latex used to make gloves or other rubber-like items. Latex inks are water-based and are compatible with a wide variety of coated and uncoated materials in addition to textiles. Latex inks cure under extreme heat and dry very fast. Soft signage is a big category for latex machines. Manufacturers of latex printers include HP (Booths 1029 and 1045), Mimaki (Booths 1231 and 1345) and Ricoh (Booth 1351).
UV: UV flatbeds can be used to print fabrics as well as rigid materials. UV inks cure as a thin polymer film, which makes UV-printed fabric stiffer and perhaps uncomfortable to wear, but can be ideal for signage or backlit fabrics such as those used in silicone-edge graphics (SEG). The polymer film adds depth and “pop” to backlits. UV printer manufacturers include Agfa (Booth 1929), Canon Solutions America (Booths 2435 and 2525), Durst (Booth 1945), EFI (Booth 1501), Fujifilm (Booth 1529), HP, Mimaki and Roland (Booth 601).
Dye: The real textile-printing action is happening in dye-sublimation and related dye-based printing, not all of which is dye-sublimation per se.
There are two primary varieties of dye-sublimation printing: transfer printing, by which the printer images on a special paper that later transfers, under heat and pressure in a heat press; or calender, the printed image onto the fabric. For chemical reasons, polyester fabrics are required for transfer dye-sub printing.
Direct-to-fabric printing (not to be confused with direct-to-garment mentioned earlier) eliminates the need for transfer paper, although it still needs to be run through a calender to fix the dye on the fabric. This type of dye-sublimation requires pretreated polyester fabrics. Inks used in direct-to-fabric printing penetrate further into the fabric than those in transfer printing, producing less vibrant colors and softer text and images, as well as more show-through on the reverse side of the fabric. As a result, the top application for direct-to-fabric right now is flags, although that is changing.
There are tons of dye-sub printer manufacturers. Start with Agfa, Durst, EFI, Epson, Mimaki and Roland.
There are other dye-based textile printing inks, which are differentiated by the kinds of fabrics on which they can print. Reactive dye inks are best-suited to natural cellulose fibers like cotton. Acid dye inks react with the fibers in natural or synthetic polyamides like silk, wool and nylon. Pigment inks can print on virtually any fabric, and cure via heat or UV radiation. However, they require a bonding agent, which can affect the vibrancy of the color but makes pigment ink-printed materials washfast.
Finally, Durst Imaging has recently introduced what it calls Durst Water Technology, an aqueous (water-based) ink for direct-to-fabric textile printing. Conceived as an alternative to UV, solvent or even dye-sublimation, the new Water Technology is said to be odorless and more environmentally friendly than other ink technologies.