The Mimaki Tx2-1600 is just one of the many digital textile printers on the market, but the one I have had the most experience with. Before I get into how it works, here’s a very brief description and history of textile printing from The Colour Museum.
Basically, the image must be divided by color, and every part of the image that is a particular color will be burned into a screen. This must be done for each color to be printed. For those of you in the graphic design field, it can be compared to a separate screen created for each spot color. Thus for every color in a textile, the amount of labor and cost go up – which can be a big limitation for independent designers.
Inkjet printing brought the ability to put a color image on paper to the masses, and the same is happening with digital fabric printing. In the case of fabric, the printing is done with dyes not inks. And because the image is comprised of pixels, there is no limit to the amount of color. It is essentially CMYK, four color process with capabilities for four extra colors.
Before printing the printer must be set up and tested. There are two different sides of dye cartridge slots. This is because fiber reactive dyes are best for cellulosic or plant based fibers such as cotton, rayon, linen or hemp. Acid dyes are best for protein based fibers like wool and silk and for synthetic fibers like nylon and polyester. Plastic gallon containers hold the excess dye from the printing process.
Next, the fabric bolt is put onto the printer. Specially coated and paper-backed fabric that comes on a roll is first placed at the foot of the printer between two plastic ends that support the roll. In order to make sure that the fabric is aligned evenly, the edge of the paper lines up with a triangle on the printer. There is a laser that detects the edge of the fabric and keeps it aligned throughout the printing. This laser is adjusted by a switch on a box attached to the bottom of the printer. The fabric is then carefully pulled in an over-under fashion through 3 cylinders to maintain the tension and then fed through the top and clamped down.
Once your fabric is ready, it is very important to test and make sure that all of the nozzles are clear. This can take several rounds of putting it through a cleaning setting, because a single lose fiber can clog a nozzle and ruin the print.
Here is an example of a test. There are boxes for each dye color made of several horizontal lines. A missing line indicates a clogged nozzle.
Now that your test is perfect, you need an image file to print. As with any desktop inkjet printer, a variety of file types can be sent to the fabric printer, but tiffs are ideal. Fabric printers will come with a software for managing the printing que, or you can print straight from Photoshop. The Mimaki can print approximately 10 square meters an hour at 720dpi.
But the work isn’t done yet. The fabric must be laid on a flat surface and peeled off of the paper backing. The dye is also only on the surface; it has not yet chemically bonded with the fibers. For this to occur, the fabric must be steamed between 120-140 degrees Celsius (250-280 degrees Farenheit) for 45 minutes to an hour depending on colors, fabric, temperature etc.
Above is the Jacquard Steam Jet, a steel bullet steamer. The printed fabric is rolled onto a hollow cylinder and then slid into the bullet steamer. After the alloted time, it is removed, unrolled, and then must be rinsed to wash away any dye that did not bond to the fibers.
A student washes out her printed yardage and then pins it up to dry.
And here is an example of the photoreal precision that can be achieved with the textile printer.
I really think it would be amazing to add a digital textile printer to Ponoko’s services. The combinations of fabric with laser cut materials would offer a whole new range of product possibilities.