Digital fabric printing is one of the most exciting technologies to reach the textile industry for a number of years. It enables designs to be printed directly onto cloth by means of ink jet or other methods, thus eliminating the need for screens, plates or films. Which means that very short runs of unique, individualised fabric designs now become a quick, practical and cost effective reality.

Although ink-jet printing onto fabric works in fundamentally the same way as any office type ink-jet prints onto paper, fabric has always been inherently more difficult to print due to its flexible nature. The level of flexibility varies from warp to weft and with each degree around the bias, so guiding the fabric under digital printer heads has proved to be very challenging. It was only as recently as 1995 that such a system was first shown to the industry by Stork Textile Printing Group of the Netherlands.

Until now, the solution has been to pre-treat the fabric and back it with paper to give it stability as it passes through the printing heads - as with the well-known American Encad system. The new Japanese Mimaki printers, however, have mechanisms to control and feed the fabric through the printer without the need for paper backing, thus enabling roll-to-roll printing. Additional built-in dryers speed up the process. It is understood that Japan's Ichinose takes a different approach where a padded adhesive bed, or printing blanket, is used as a surface to guide the fabric under the print heads. Using these various solutions, almost any type of fabric can now be digitally printed.

The actual method of printing, though, is only one of the technical difficulties. For example, the ability to print a wide colour gamut whilst controlling colour density needs to be considered. Different dye types are also required for different fabrics; and, because of the differences between the print heads on digital and more traditional textile machinery, each must be formulated in a different way. These inks must not adversely alter the feel and drape of the fabric; they must be light-fast, stand up to constant friction, and retain colour vibrancy; and, when used in a production environment rather than purely for sampling, they must be washable and/or dry-cleanable.

Before any printing is carried out, the designs need to be developed in a digital format that can be read by the printers. Thus, all development has to be based on co-operation between the design software companies, the ink manufacturers and the printing machine developers.

The technology is still in its very early days, but the possibilities for its use are extremely exciting. Potentially, it is as flexible as the printer on a basic PC, offering a technique that is cheaper and faster than traditional printing yet with no minimum production run. This means that anything from a sample swatch to a one-off garment or product, as well as long or short runs of fabric, can be printed, with no set-up time or costs between different prints, and no limit to the intricacies, detail or colours within the design. No plates or screens need to be produced. Any idea, picture, or even a photograph can be scanned into the computer, the design can be modified at will, colours changed, detail added, and then printed out onto whatever fabric is required.

Mass customisation, where a high number of very small orders or one-off products can be produced cost effectively, becomes a reality. Fabrics for corporate clothing, club wear, blouses, ties, jackets, dresses - even furniture - could all be produced to an individually unique design for any customer, quickly, easily and cost-effectively incorporating logos, company colours, or almost any other idea.

With upholstery, for example, wallpaper could be scanned, the design adapted, and co-ordinating fabric produced. Material would be printed only against the order on a true 'just in time' basis, thereby eliminating risk and reducing stock-holding, at the same time as providing maximum control and flexibility at minimum cost.

If this idea is taken further and coupled with recent improvements in automatic marker making to produce the cutting plan used to cut out pieces from the roll of fabric, together with the significant developments in single ply cutting, then it is not a quantum leap to envisage digital printing and cutting as a synchronised operation. The single ply could be printed within a pre-defined pattern and marker, thus saving time and ink wastage, and bringing ecological as well as financial benefits. The fabric would then move through to the cutting area to be cut as a single ply.

Assuming this to be possible, the next stage must be to address checks, stripes and motif matching. If one can print only those areas that are needed on the fabric, and as they are required, instead of laying out the pattern pieces into the marker to match, it should also be possible to print the patterns onto the product pieces to match. This would enable the tightest plain fabric marker to be used; the layout of the checks, stripes, motifs, etc., would be automatically positioned on the pattern pieces (rather than the other way round) and printed, resulting in considerable fabric savings and thus cost.

One of the main problems in the acceptance to date of digital printing, apart from prior limitations on the types of fabric that could be printed, is the relatively slow speed of printing (currently between 3 and 7.5 metres per hour). Stork's Amethyst non-stop printing system can produce about 350 square metres per day (20 hours) with unlimited colours and style variations and is probably one of the quickest on the market, along with USA ColorSpan's twelve cartridge head DisplayMarker FabriJet X11 printer which can print 72" wide fabric at 28 square metres per hour for short run production. This printer is equipped with heated dryers above and below the fabric to ensure the ink is fully dry before the fabric is rolled onto the take-up spool. An on-board humidity sensor automatically slows down the print speed if the printer is operating in a high humidity environment. It does not appear that these types of speeds will be dramatically improved on the short term.

The inks available are, however, continuously improving. A wide range of reactive dyes is now available: acid dyes mainly for silk, and dispersion dyes mainly for polyester. Pigment inks will soon be available too. For more industrial type textiles, solvents containing inks and oil based inks are being introduced.