The march of digital printing methods continues to impact on every industry where there is a need to lay colour dyes or pigments down onto – or into – a substrate material.
The perception of printing is inexorably tied to paper, with the fibre that makes it coming from trees, even though much wide-format digital printing is performed on vinyls, synthetics and other plastics. The irony is that paper has only been made from pulped wood since the mid-1850s. Prior to that virtually all paper was made from recycled cotton rags mixed with other non-tree fibre such as certain grasses and even hemp. Even today, acid-free cotton-based papers are highly prized as substrates for archival digital printing such as art reproductions.
So, printing began as a textile-based process! A Chinese nobleman Ts’ai Lun is credited with making the first paper in 105AD, to replace expensive silk used by Court calligraphers. He used rags, fishing nets and grass to make the pulp. In Europe, even after the invention of modern printing, animal-hide parchment or vellum, as used by scribes, was the substrate Gutenberg used to print his first Bibles.
Fast forward to the present, and there is much excitement about the potential of digital imaging on textiles and no wonder; the global textile and garment industry is estimated to be worth more than USD$4.3 trillion according to a 2012 Insight report by ANZ Bank*. Even a small percentage of that massive market is attractive for short-run digitally imaged textiles.
Not Just About Garments
Printing textiles digitally offers great potential for designers to create unique patterns that find their way into garment manufacture, but this is by no means the sole use. Demand is increasing for ‘soft signage’ where billboards and exhibition displays are printed onto lightweight and easily transportable textiles instead of heavy and cumbersome PVCs, rigid panels and plastics. Wall coverings, interior décor such as curtains, furnishings, cushion covers and even carpets are being printed using digital inkjet technology onto textile-based media. A long-established application is the digital printing of mattress coverings. Printed textile mesh can be seen shrouding many building sites and fences.
The conventional printing of textiles uses various processes, the most common one being screen printing. Others include the use of rotary cylinders, blocks and stencils. The goal of all processes is to embed the dyes used into the fibres of the fabric, since when deployed, these fabrics will be repeatedly washed, rubbed and subject to outdoor UV light. Fixing the dyes is a separate process involving heat, steam and calendering. With digital inkjet, four processes have developed, most of which need polyester or a cotton-polyester-elastane mix for best results:
- Heat Transfer
- Direct to Garment
- Dye Sublimation
- Direct sublimation
Heat transfer involves printing onto a carrier sheet that is then pressed onto the material at high temperature. The dyes do not imbue themselves into the fibres, and this method is regarded as a short-term method for decorating T-shirts and other projects where it is acceptable for the image to sit ‘on top of’ the fabric.
Direct to Garment is also favoured by T-shirt printers, but using inks without a carrier sheet. An explosion of DTG printers has happened and even mainstream printer manufacturers such as Epson are now offering DTG T-shirt printers and inks.
Dye Sublimation provides by far the most stable and hard wearing solution to digital textile printing. Images are printed in reverse on special sublimation paper, which is then pressed in contact with the textile under heat and vacuum in order to sublimate the dyes into the fibres of the material. The dyes actually become gasses to infiltrate the fibres, returning to a solid state once cooled. Following fixing by steam, washing and heat, the images are bright and vivid, with the ability to withstand repeated washing and detergents. Dye Sublimation digital is responsible for producing the majority of Australia’s sports team apparel.
Direct Sublimation is similar to Dye Sublimation but eliminates the carrier sheet: inks are jetted directly into the material under pressure. While offering much promise as R&D presses ahead, Dye Sublimation still rules the quality end of the digitally printed textile market.
All of the above digital inkjet methods can be printed using either modified standard wide-format printers, or dedicated inkjet textile printers. Fujifilm offers the outstanding JTeck sublimation inks for all leading brands of inkjet printers, in combination with Coldenhove sublimation transfer paper that ensures 100 percent dye transfer and eliminates gassing-out issues.
The worldwide printed textile market is experiencing a gradual slight shift away from mass production in heavily capitalized and labour-intensive regions such as China, to more focused and nimble sites where short-runs of bespoke designs can respond to fast-changing market demands.
This trend favours digital production and can even be attributed to bringing some production back into markets such as Australia where the designs are formulated and, instead of being sent offshore for production, are produced locally.
There will always be mass offshore production so we can enjoy those affordable clothes from the department stores but, for the astute digital business, printing textiles digitally offers excellent growth opportunities and further challenges the definition of what it will mean to be a ‘printer’ in 2015 and beyond.
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*ANZ Insights Commercial Banking Asia – Textile & Garment Industry market update – July 2012 available at www.anzbuisness.com