The newest and hottest trend in decorated apparel is direct to film (DTF) printing, a transfer technology that allows users to print designs onto polyethylene terephthalate (PET) film using water-based pigment inks. Since it is a transfer technology, the design is printed in reverse order compared to traditional digital printing. The CMYK colors are printed first, followed by the white ink; the image is reversed so that its orientation is mirrored. The wet ink is powdered with a hot-melt adhesive and then cured. Once cured, the image can be transferred to an apparel item using a heat press.
So why has DTF boomed? When compared to direct-to-garment (DTG) printing, DTF offers the ability to avoid fabric pre-treatment, which is often required when printing with DTG. DTF will also work on fabrics like polyester and nylon, which are often difficult (if not impossible) for DTG. There is a much lower learning curve for printing DTF transfers compared to DTG. When compared with dye-sublimation, DTF offers the user an ability to decorate a wider range of fabrics and fabric colors. Not to mention DTF is more cost efficient compared to other transfer technologies like heat-transfer vinyl, as there is no cutting and weeding with DTF, saving time.
As with other digital print technologies, DTF is great for full-color, photorealistic images. Color is only limited by the gamut of the inks being used. Fine lines, small text, and high detail images are no problem for DTF. That said, color profiling can be a challenge for those unfamiliar with color management and ICC profiles. Special RIP software is also needed to create a white print layer and to mirror the image so the transfer prints in the correct orientation.
The majority of DTF printers have emerged from China and are often modified Epson printers or platforms using Epson printheads (models commonly include 1-4 printheads). Optional configurations include additional printheads to jet added white, CMYK, or fluorescent channels. Print speeds vary based on the number of printheads. However, printer models offered fall within one of three categories: slow (25-35 ft2/hr.), medium (80-100 ft2/hr.) and fast (150+ ft2/hr.). Costs per square foot, including PET film, ink, and powder adhesive, range between $0.50-$0.90 USD. While washfast durability being reported is above 100 laundry cycles.
Mongoose 24” DTF Printing System with Powder Adhesive Coater and Dryer
While preparing the image for print is particularly important, applying the hot-melt adhesive is equally so; it is a hot-melt powder made of polyurethane resin ground into adhesive powder. While there are no harmful emissions, the powder adhesive is exceptionally fine and can generate dust, so it’s best to wear respiratory protection when working with the powder. It is also good to keep the inkjet printer at a safe distance from the powder coating process to keep adhesive dust from penetrating sensitive parts inside the printer.
The powder comes in white and black, depending on the general color of the fabric to be decorated. The powder is best applied using an automatic powder shaker for rolls of printed PET film or it can be manually applied when using cut-sheets of PET film. The biggest factor of applying the powder adhesive is achieving a consistent, even coating. Once cured, the transfer is applied at 315°F (157°C) for 15 seconds at medium pressure for cotton fabrics. For heat sensitive fabrics like polyester, the press time can be reduced.
The newest DTF technology is the CobraFlex line of DTF printers that require no powder adhesive. With this system, the transfer adhesive prints at the same time as the white ink pass eliminating the powdered adhesive process, and the dust it can generate. This new approach is a developing trend in inkjet printing whereby chemistry is being jetted in addition to CMYKW inks.
CobraFlex No Powder DTF Printer
In just over two years, DTF has emerged as an all-for-one technology. It provides the ability to decorate a wide range of fabrics, does not require fabric pre-treatment, is durable with great elasticity and stretchability, and is a cheaper and faster alternative in many cases.
While OEMs are slow in reacting to market demand, there are signs of movement. Eastman Kodak Company (Rochester, NY) recently entered the DTF market by launching its KODACOLOR Film-to-Fabric ink system that includes powder adhesive, PET film, and ink specifically designed for DTF transfers. STS Inks (Boca Raton, FL) offers a printer using Mutoh’s VJ-628, and offers powder adhesive and PET film branded with the STS logo. Many direct-to-garment OEMs like Epson, Kornit Digital, and OmniPrint International have promoted the ability to print DTF transfers on their DTG devices using cut-sheet PET film and their existing DTG inks. It will be interesting to see if other equipment OEMs or ink manufacturers will jump on the wave of DTF and develop dedicated printers, inks, powder systems, and PET films. In this case, lightening only strikes once.
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