The importance of inks in direct-to-fabric digital printing

In direct-to-fabric printing, the choice of inks contributes to the success of the final result. We asked Angelo Marelli, R&D Manager of Epson Como Printing Technologies, to explain what factors every professional should take into account.

First of all, when we talk about inks for digital printing on fabric, we have to distinguish between inks for direct printing and inks for sublimation or transfer printing. The former are inks formulated to print directly onto fibres, both natural and synthetic. These are water-based inks available in different types: reactive, for printing on cellulose-based fibres such as cotton, linen, viscose, hemp; acid, for printing on silk, wool and polyamide (nylon); disperse, for printing on polyester substrates. Finally, pigment inks are compatible with both natural and mixed fibres.

How do you know which ink is best suited to your production needs?

The choice of ink depends, first and foremost, on the printing technology. Digital inks must be formulated to be compatible with the printheads used to guarantee continuous efficient output and ensure maximum print quality and reliability. Ultimately, the chemistry of each ink is designed to "work" optimally with the characteristics of a specific type of printhead. The solutions in Epson's Monna Lisa range use EPSON PrecisionCore proprietary printheads, which are designed to ensure precise and pre-determined delivery of ink droplets onto fabrics, avoiding waste and chemical leakage.

Another factor to consider is your target market. All commercially available DtF printing solutions are designed to accommodate eight-colour ink sets. Depending on their production requirements and the target market of the fabrics, the printer chooses the most suitable colour configuration. This means that apart from the inks required - which can be the same for different types of fabrics, e.g. acid inks are used for both silk and polyamide printing - it is the expectations of the target market that determine the characteristics of the printed product and the printer's choices. Also in terms of the performance required of the final product. For those who print on silk for the production, for example, of scarves and ties, the need is to obtain a final fabric rich in nuances and resistant to dry cleaning. For a company printing polyamide and with a target market of beachwear and sportswear, the ink configuration may also include fluorescent colours and the prints will need to be chlorine and light resistant.

Epson's R&D team has embarked on a journey to extend the range of inks to ensure that customers who choose to print with MonnaLisa will have similar performance to screen printing, both in terms of colour gamut and performance. Beta testing is currently underway to refine our range of acid inks, ensuring even greater versatility of application.

Environmental sustainability is a key focus that continues to drive our research and development in both printing technologies and chemistry. For this reason, all GENESTA inks are OEKO-TEX and ECO PASSPORT certified. Reagents and pigments are also GOTS certified, while acids are BlueSign certified. The use of pigment inks, in itself, results in further savings in water and energy resources, thanks to the elimination of the steaming and washing phases of the fabrics.