Digital Textile Printing

DIGITAL TEXTILE PRINTING Introduction Digital textile printing” is a phrase typically used to describe the process of inkjet printing on fabric. On the surface, this sounds relatively simple. However, the words “fabric” and “textile” encompass a wide range of substrates that differ in ways that include fiber type, fabric construction, and preparation. From the coloration perspective, these factors have dictated the need for the development of specialized printing systems that include a combination of hardware, software, ink chemistry, and auxiliary equipment for fabric preparation and finishing. These digital print systems have been engineered with the goal of managing the variables and optimizing the results of digital imaging on textile substrates

The Market

Figure 1 Market Overview, Digital Textile Printing Present Markets Sampling Strike-Off Mass Customization Future Markets Batch Production Printing Low-Volume Demand Printing

The Industry Size 300,000 Retailer "Doors" 20,000+ Manufacturer "Doors" 400 Companies Manufacture 80% of all apparel Apparel & Related Volume is $180B All Others’ Goods represent $36B

Source: I.T. Strategies Source: J. Early, TC2

Inks

On the technology front, inks come through as a major frontier. According to Ray Work of DuPont, the worldwide market for textile chemicals is at $22 billion, of which around 36% is dyes and pigments. Finishing and coatings comprise 38%, with the balance other printing chemicals, sizings, prep chemicals and miscellaneous. A major advance, according to Work, is that now almost every type of fabric can be digitally printed by ink jet, thanks to progress in inks. For example: Ink Type Acid Dye Dispersed Dye Reactive Dye Pigmented

Fabric Type Silk, Nylon, Wool Polyester & Synthetics Cotton, Linen, Rayon, & Silk All Fabrics

Work notes, of course, that DuPont has pioneered pigmented colorants for ink jet inks, and cites many advantages. The importance of pigment inks in textiles was highlighted by his breakdown of the overall textile market showing that cotton is almost half the worldwide pie (Figure 2). Among the characteristics he mentioned on the textile industry supply side are that it's an old, conservative industry, it has been using 30-year old printing technology designed for long delivery times of long run orders, and is characterized by fierce competition which translates to oversupply and pricing pressure. On the demand side, the forces all seem to support the case for digital printing: increased importance of private label marketing, implementation of ever more sophisticated information technology, and demand for smaller lots, faster delivery, and exclusive

designs. Besides meeting these demand side trends, digital printing was said to also offer integration of production into the digital work flow and impose much lower environmental costs.

Turning to specific inks and printing processes, BASF offers three alternatives. One product involves three steps plus printing: pre-treatment of the fabric for proper fixation of reactive inks, printing, heat (steam or bake) to bond the ink to the fabric, and, finally, wash-off. Their transfer inks require first printing on paper and then hot press transfer to the fabric. The third approach is a one-step direct printing ink which requires only printing onto the fabric and dry heat fixation.

What is involved in “Traditional” Printing ?

• Colors and Patterns are applied through rotary screens • Each color in the pattern is applied one at a time usually from dark to light • Engraved areas allow color to pass through and form a pattern • Screens are adjusted so that the printed areas fit together “registration” The Advantages of Digital Textile Printing

To date, the key drivers in adopting digital textile printing technology for traditional textile printers has been the reduction of sampling costs and time to market. In conventional textile screen printing, the development cost for stirke-offs and samples are $4,000-$8,000 (USD) per design, with the cost fluctuating based upon the number of spot colors used in a design. The development of these screens and strike-offs takes from 2 to 5 weeks. With digital textile printing there are no screen costs, and a sample can be printed upon demand.

However, with the textile industry using this technology only for strike-offs, while moving to conventional screen printing for their production needs, it is failing to incorporate many of the key benefits and design opportunities that the new technology provides. These benefits include the ability to use an unlimited number of colors, excellent reproduction of continuous tone images, unlimited repeat sizes and the ability to print engineered designs across multiple seam lines.