Digital textile printing is described as any ink jet based method of printing colorants onto fabric. Most notably, digital textile printing is referred to when identifying either printing smaller designs onto garments (t-shirts, dresses, promotional wear; abbreviated as DTG, which stands for Direct to Garment) and printing larger designs onto large format rolls of textile. The latter is a growing trend in visual communication, where advertisement and corporate branding is printed onto polyester media. Examples are: flags, banners, signs, retail graphics
As prepared-for-print fabrics and digital printing systems and inks continue to improve it is reasonable to assume demand for the technology will increase. To get the best results from a digital textile printer, considerations for the production process and its distinct but related stages are essential.
With years of technical knowhow and experience in the manufacture of textile colorants and electronic materials, KISCO has now developed and produced digital printing inks in order to meet increasing market demand. This is the PAPIJET series of water based inks for digital textile printing.
For many in the industry, “dye sublimation” is synonymous with digital textile printing, but in reality sublimation is just one of several processes that can be used. Theoretically any large format printer that can print on fabric can be called a fabric printer, but for the purposes of this blog we are speaking only about true digital textile printers that are engineered to bond or infuse ink into fabric rather than technologies such as latex or UV that lay ink on top of the surface of fabric. All of the inks we refer to below utilize water-soluble dyes.
Let’s take a look at the different textile ink options: dispersed, reactive, acid and pigment. Disperse inks are the most commonly known type of digital textile inks, and this is what is used in the dye-sublimation ink process. Dispersed inks infuse into and actually dye the fabric, becoming part of the textile itself. Disperse inks are broken down into low-energy, medium-energy and high-energy dispersion. Our commonly used “dye sublimation inks” are actually a low-energy dye dispersion, most typically used for transfer printing from paper to fabric. The sublimation process requires the use of a calendar to deliver heat and pressure. When the ink and carrier is heated to a high temperature (typically around 380-400 degrees F) the carrier evaporates and the dye turns to gas. The synthetic fibers “open” to receive the gas and when they cool, they close and encapsulate the colorant, which then returns to a solid, actually dyeing the material. Reactive ink contains dyes that create chemical bonds with cellulose when applied to pretreated fabric and then fixated. Reactive inks do best on linen, rayon, nylon and other cellulosic materials. Acid inks require pretreated fabric for fixation and are printed directly to the textile then steamed to set the ink. The dyes that make up acid ink create ionic or electrostatic bonds with textiles such as silk, wool, and nylon. Fabric with reactive and acid ink must be washed after transfer to remove any residue. Reactive and acid-based inks also have to be set into the fabrics with a post-processing heating procedure to permanently set the dyes. Pigment inks are finely ground powders suspended in liquid carriers with binders. Where sublimation creates permanency when the dye is encapsulated into a polymer, pigments are bonded to natural fabrics using binders and a heat calendar process. Digitally printed natural fabrics are in high demand, so this is an area we expect to see significant growth in in coming years. Here is a summary of which inks are best for particular types of fabric:
- Disperse and sublimation are used on polyester, acetate rayon, poly-Lycra® and acrylics and require post treatment heat
- Reactive dyes are for cotton, linen, rayon, nylon and other cellulosic materials and require pre- and post treatment
- Acid dyes are best for wool, silk, polyamides, cashmere, angora and nylon and require post treatment
- Pigment works on cotton and natural fabrics and requires post treatment heat
Basically, it is appropriate for customized product and frequent design changes to meet the rapidly changing customer choice. The intended purpose of the project is to create consent about digital printing. Keywords: Ink jet printing; color management; Ink chemistry; Textile substrate, Mass customization