HOW DIGITAL TEXTILE PRINTING WORKS
To better understand how digital textile printing works on fabric, and to help you define your needs and possible solution requirements, we have defined the 5 basic parts to the process.
Fabric comes in many different properties such as natural fibers, 100% synthetic, blends of synthetic and natural fibers and in either 2 or 4 way stretch or non-stretch. Each fabric can be digitally printed and you have choices of ink that allow you to print on these fabrics. Many of our customers print natural fiber, non-coated fabrics with our P50i Pigment ink for soft furnishing and fashion applications because of how easy it is to fix after printing. However, some customers use our dye sublimation inks for their synthetic fabrics because of the desired color gamut and how the finished product will be used. (Example: flags and banners, sportswear or soft signage) Knowing your fabric helps define the printing solution.
The biggest question to address when it comes to digital textile printing is what ink to use, and the answer is determined by the desired fabric and use of the fabric. See the chart below for a general description of what ink is used on different types of fabrics and the necessary finishing steps for each ink.
Pigment ink – Natural and Synthetic fibers: Currently the ink we manufacture the most for soft furnishings, interior decoration and fashion clothing is p50i pigment ink. This ink is a true pigment ink in that there is a pigment colored particle suspended within a binder system in the ink. The binder enables the ink to adhere to the fiber after fixation (roll fixation Calendar). There are 8 colors in the ink set including; Cyan, Magenta, Yellow, Black, (true) Gray, Orange, Violet and Red. This ink set provides for a good color gamut, though the color gamut is not as wide as is possible with dye-based inks. This ink can also print onto the widest range of fabrics including cotton, silk, rayon, cotton/poly blends, and 100% polyester in a variety of weights. No pre-treatment is necessary however optional pretreats are available that increase the color gamut and also the wash fastness but a specific pretreat machine is required. This is becoming extremely popular as Pigment inks are a greener solution that require no water and specialized fixation, steaming or washing etc in process. And when a printer and pretreat machine are added the results are quite spectacular and favored by architects and designers.
Acid & Reactive ink – Natural Fibers: There are 2 different types of common dye based inks available to digital printers. The dye-based inks require the use of a fabric with a specific pre-treatment. Acid and Reactive inks require moist heat as in steaming for fixation. The advantage of the dye-based inks is the color gamut is wider. A general rule of thumb is that the same type of ink should be used digitally in an application that is printed by screen printing. A softer hand or feel is common along with a better wash fastness because of the nature of the Dye inks. Dye inks penetrate fabrics extremely well but require a lot of processing steps to make it ready for use. Typically pretreating, heat, washing and steaming are employed to fixate fabrics. The equipment required in process is typically industrial and specialized. We recommend Acid and Reactive inks for larger scale operations where the meters printed per hour warrant the capital investment.
Sublimation/Disperse Dye ink – Polyester, Lycra and Spandex: applications for Sublimation ink is banners or flags, soft signage and sportswear. The fabric is typically high content Polyester, Lycra and Spandex. Sublimation is the most popular with class 1 and 2 printers. Once printed you transfer off a sublimation ink receptive paper roll or direct print to the fabric. Heat fixation >200ºC is needed for the gaseous dye transfer to polyester fibers. The colors are brighter and leave no hand or feel are wash and UV stable. For higher speed printers it’s essential to have a degassed ink delivery system and the print heads that is used will need to have a calibrated ink to perform well, or offer long term repeatability. The heat fixation process is either with a Heat Press or Roll fixation Calendar. A broad range of colors (15) including Neon are readily available.
There are several types of printers in the market, but all of them can be placed into 1 of 3 classes based primarily on types of ink or fabric feeding methods.
Class 1 type printers generally run sublimation/disperse dyes in combination with transfer papers – Sizes of printers and speeds are relative to your market needs. Curing is either by heat press or heat fixation Calendars. (Sportswear manufacture, soft signage and hard surface products).
Class 2 printers are for direct to fabric printing and generally are the same printer but with a gutter for printing strike through. This is especially useful in banner printing, like class 1 they still use sublimation/disperse dye inks but can print direct to non-stretch treated polyester fabrics. Curing is mostly done with a roll fixation Calendar. (Sportswear and Soft Signage note: Calendars will transfer and fixate cut pieces for apparel manufacture).
Class 3 printers are designed to print fabrics with stretch. Typically Synthetics and natural fibers that have 2 way or 4 way stretch properties. The main difference is that the feeding system has been developed to make sure there is minimal shift in the fabric as it is fed through the printer. There is primarily two types of stretch fabric feeders. One utilizing a large blanket or conveyor that needs a glue to be applied so that fabric is held firm while being printed. The other type is via a roll fed device with a pressure roller. Both work well but it really is dependent on the speed of the prints and type of printer that is incorporated. For example the lower cost industrial Japanese printers like Roland, Mimaki and Mutoh typically run at production speeds of depending on the model– A roller fed device will be all that is needed because of the relative slow speeds of print and fabric feed. A bespoke printer with larger heads like Ricoh, Konica Minolta etc will run a lot faster because of the number of print heads they use – These printers can reach speed up to 200-400sqm/h and all typically employ a sticky belt/blanket.
The software that comes with the printer converts the data generated in the design created on a computer into information the printer can understand. It will optimize the colors of the design to get as close a match to what you want as possible. It also tells the printer where to place the ink drops and in what size. Some software programs will also let you manipulate an image with steps, repeats and drops so that you don’t have to do that in the design software such as Photoshop.
The ink and the fabric you choose will determine how your fabric needs to be fixed (finished):
- Pigment Ink – Dry Heat – Typically through a roll fixation Calendar or Heat Press
- Acid Dye – Steam – Wash – Dry – Typically large Industrial specialized equipment
- Reactive Dye – Steam – Wash – Dry – Typically large Industrial specialized equipment
- Dispersed Dye/ Sublimation – Dry Heat – Typically through a roll fixation Calendar or Heat Press
At Pigmentinc we have been processing fabrics digitally for well over decade and our combined expertise in ink manufacture and fixation has led us to be the first choice for a number of well-known brands and companies. We specialize in-plant setups and can deliver textile decorating solutions through all stages of the process. From simple t-shirts to all over building banners. We also offer a training facilities in Australia, Singapore, Europe and the U.S to help operators, and educational facilities understand the correct process and techniques.
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