Understanding the differences in printing technologies is an important step in making printer decisions.
By Dr. Nicholas Hellmuth
Fabric graphics are everywhere. With the pressure on to innovate and diversify to weather the current financial turmoil, more companies may be looking at printing, or partnerships with companies that print, or expanding their own printing capabilities to offer their customers value-added products and more options. However, with many more fabrics, inks and printers available, everyone from the potential dabbler to the printing professional must do his or her homework to make informed choices, including fundamentals on current printer technologies.
Transport belt printers tend to be on the high end of the price range, and dedicated flatbed printers are rarely used, since fabric generally comes in a roll, so roll-to-roll printers comprise the bulk of the market. These are the options:
Paper-backed textiles through regular nontextile printers. HP offers printers, such as the Designjet 5000 and 5500, that can accept paper-backed textiles. The material must have a paper backing to feed through the pinch roller and grit roller system. This kind of material is expensive and the operator is limited to HP inks, rather than textile inks. Most print shops that wish to seriously pursue digital printing on fabrics may experiment with a printer they already have, but quickly realize its limitations and will begin looking at a more sophisticated solution made for textiles.
Modified roll-to-roll. Mutoh offers its versions of the Viper, and Roland has offered printers labeled and advertised for textiles, but as long as they have the pinch rollers and grit roller system, they are meant for wallpaper and other paper-backed materials.
Sophisticated roll-to-roll with tension rather than grit rollers. These printers use tension to pull the fabric and spreader rollers to keep creases from growing as the somewhat stretchable fabric feeds through the system. The MC3 from Yuhan-Kimberly (DTP Link) has a fabric transport system sufficiently innovative that aspects have been patented. More importantly, the company offers a bulk ink system that is a vast improvement. The real advantage is having a company to back you up with significant knowledge about how to handle inkjet-printed textiles from A to Z, from precoating to postfinishing.
If a manufacturer concentrates on making solvent printers, it will be good at this, but may not have the in-house expertise in fabrics, textile inks, calendering, heat fixation or the markets for these products. Good examples of alternatives to a solvent-oriented solution include DigiFab, because everything it does is related to inkjet printing on textiles, and Yuhan-Kimberly because textiles is its business.
Roll-to-roll with sticky belt moving transport system. This is the next step up. Many companies offer these, especially in Italy. In the U.S. you can see these at d-gen, Yuhan-Kimberly and DigiFab (the StampaJet), among others. The newest model in this high-end market is from a cooperative project between Yuhan Kimberly and Keundo—the K2 model. There are many other brands of modified Roland, and occasionally modified Mutoh or Mimaki printers with a transport belt added, but most offer four, six, or eight colors. Yuhan-Kimberly offers 12 colors, in part because it is its own ink manufacturer for reactive and nano-pigmented inks.
Two additional roll-to-roll printer types are the stand-alone printer with adjacent stand-alone heat fixation, and the integrated printer with fixation.
Companies consider many factors when choosing a printer
In choosing a printer, decide first which fabrics you need to print on. If everything is polyester-based, dye sublimation is the usual route. If the fabrics are stretchable material, it’s not really the ink that is the deciding factor, but the manner of transporting the fabric through the printer without stretching it.
Price is obviously a factor, but you get what you pay for. For a small print shop interested in growing, versatility is crucial. A large print shop is best served by having several different printers, each one dedicated to specific applications.
Durability is important in all printers. Printers made by Keundo, Dilli, DGI, IP&I or Yuhan-Kimberly in Korea are recommended. The Truepress UV printers of Dainippon Screen are an excellent example of the kind of quality that Japan can produce. Be wary of printers whose record in quality control may not be reliable. Stick with products from companies with a fair and acceptable track record in wide-format printer manufacturing.
Setting goals for the future
A prime goal of the textile printer manufacturing industry is to create a textile printing factory, so to speak—an inkjet printer that will replace screen printing. A second goal is to build a textile printer for the masses—a textile printer that will sell in the thousands. This could be the new Yuhan-Kimberly MC3 textile printer. The MC3 Premium handles all fabrics, including stretch fabrics, and the K2 is a high-end production machine with 12 colors and MEMS print heads. Since 1999 Yuhan-Kimberly has been the ink developer and manufacturer for many of the popular water-based, wide-format inkjet textile printers.
Dye sub trends
For dye sublimation, one trend is to avoid using a separate calendering machine. Print shop operators want to print and fix, all inside one unit, but when they have a full-scale two-step system—printing onto transfer paper in their printer, and doing the dye sublimation in a Monti Antonio, Klieverik, AIT (Transmatic), Practix or DigiHeat system—they say that the colors “pop” more. So there is still a bright future for these five leading manufacturers or distributors of dye sublimation heat fixation equipment.
In general, people tell me they wish they could print easily on materials other than just polyester. This is an advantage of a system such as the K2 of Yuhan-Kimberly. It can use nano-pigmented ink or reactive ink and thereby print on many more materials. DigiFab’s swatch book shows that this company, too, knows how to produce colors that pop. The demo room and display area colors of DTP Link (Yuhan-Kimberly) in Seoul, Korea, are equally impressive. So one trend is toward a printer that is flexible enough to do dye sublimation if desired, but can also handle reactive or nano-pigmented ink for more diversity.
Companies strive to achieve one-pass printing
The dream is to be able to print everything in a single pass, but problems persist—specifically detecting failed nozzles and creating a replacement nozzle on the fly. Newer alternatives give up trying for one pass, and instead simply do page width but at about four passes. The new HP Scitex FB7500 UV-cured flatbed for flat and thick signage is an example.
Also, on the HP Scitex and on the VUTEk DS system, the print heads must move enough to cover their tracks, so to speak. This is why real one-pass printing is not realistic yet. Extra passes are needed for two reasons: to cover banding tracks of missing or misdirected nozzles (to cover the path edges between one print head and the adjacent one); and to achieve a color saturation that will make the image pop with intense coloration. Most one-pass systems can’t jet enough ink to provide the “pop” that signage needs.
There is, however, a new printer from Grapo, a Czech company, that claims successful one-pass, but in wide path rather than page-width. Wide path means a printing pass width of 20 to 30 centimeters. This new printer uses UV curing and will be priced one-half million Euros because they do not need the entire “page-width” of solid print heads, making it a cost-competitive alternative.
Universal ink is the future
In general, the future belongs to whichever manufacturers can develop the next universal ink. UV-cured ink is currently the ink that can print on everything, including textiles, but UV-cured ink is primarily a temporary solution to resolve the VOC and sustainability issues of solvent and screen printing inks.
UV-cured printers will be dominant the next five years, so you can buy one now and be confident that it won’t need to be replaced immediately, and it should be a profitable move before the next new ink technology arrives. However, the day will come when either a water-based or alcohol-based ink will take over.
In any case, waiting until next year when the next-best-thing appears may not be the best decision. There will always be a newer, faster, more sophisticated printer. If you wait, your competitor, who did not wait, will harvest those clients. Likewise, look to innovate and expand your offerings with specialized applications and be the first to introduce these innovative products into your market area.