This is an overview of what is happening at this moment with digital printing of textiles and what the future trends are.
Starting with some facts. If we look at the worldwide production of printing, we see that a lot of production, analog production, using screens is in Asia, in China, India, and a lot of countries outside of Europe. Perhaps some facts today, we have 40 billion square meters which is printed on. A lot still… another… a lot is still with using screens but in the future, digital will break through, so there is an opportunity for 40 million square meters in the future. Today, it’s only 1 or 2 %, but it’s growing anyway. 60% of all consumption is in Europe, China, Japan, and the USA. 60% of all production is in China, Bangladesh, Pakistan, Vietnam, Thailand, and Indonesia, of the conventional production. If we look like traditional printing and the main fibers that are used, we see that a lot of fibers are cotton fibers. This is because also in traditional printing, people are trying to use for the easiest way to print something. And the easiest way to print something is using a pigment and then afterwards just a heat treatment. The other fibers which are less presented, for example, a polyester fiber, is printed on with a dispersed dye. This is already a little bit more difficult to print, even conventional. And then we see a lot of fibers that are very… only have very small parts like silk, wool, nylon. This is because these fibers are different very difficult to print. You really need a lot of expertise and a lot of technique. Even using conventional printing to get higher resolution, it’s very extreme procedure, it’s a long procedure, you need a lot of water and you also produce also a lot of waste. So there, there is a large opportunity for digital at the moment.
So if we make a prognosis for DP, we see that it will grow in the future and that it will double and perhaps it will completely be replaced… perhaps it will replace the conventional printing completely in the future. So if we see you today at mainly digital printing is done on flags for the graphical sector and then it will look at everything that is apparel and that it’s fashion, it’s only a very small part of this represented. And there is a challenge to go to more digital production. So today, we have two to 5%, but in the future this will go anyway. If we look at the upcoming EU-Markets for DP printing, we see, for example, Turkey, Spain, Portugal. If we look at Soft Sign, we see Germany, Scandinavia, Belgium, Holland. If you look at Fashion, it’s mainly Spain, Italy, that really our fashion producers; production, for example, scarves, the silk scarves which are printed digital etc. And it today, Starting, digital printing is also in UK, etc.
The change is clear: from analog to digital:
So the change it’s from analog, from screens to digital anyway. We see that in, for example, digital printing, the way to the market is a lot shorter. So if you work by a conventional procedure, we have first the design, we have to make a color separation, we have to make a screen before we can sell something. If we use digital printing, we can go over these steps quite quickly. So we receive a design and if we have the right software, if we have the right printer, and if we have the right textiles and inks we can start printing immediately. we can indeed start printing, if everything fits of course. So there are a lot of benefits in digital printing, for example, a lot less waste, we don’t need screens to be stopped somewhere so there is a lot of less waste, etc. So reduced stocks, virtual stocks, economical and ecological benefits, we have faster and more frequent design changes etc. So in fact, digital printing, we can see we don’t have stock, we don’t have waste and we don’t have set-up costs if we want to make a production.
If we look at the markets of digital printing today, then we can in fact divide the markets into some conventional textile markets such as Apparel, Fashion, Soft Sign and then the Carpet, Tiles, and Rugs which are traditional textile markets, it’s there we want the penetration of the digital to be larger. And then we also have some new textile markets for digital printing such as Technical Textiles and Home Furnishing. So the largest challenge at this moment is to introduce digital printing for fashion. There, we really can get large turnovers if we introduce it in the right way.
I will show you some application of digital printing today. So we have to think in concepts and not as before. If we look at the basic components, if we… sorry. If we look at the basic components of digital printing, there are 4 components which are quite important to get the right result. This is the hardware- meaning, the kind of printer that you will use to get the result. Is it the small printer or small, large format printer? Or is it really a high production speed printer?
Then very important is the type of software that you will use; which kind of RIP system will you use to transform the colors in the design to your textiles; so the recalculation of the colors. Here we approach, as textile people, colors in a different way than, for example, people from graphical sector. As textile people, we want to have some influence on the color. So the approach is slightly different from, for example, soft signage and conventional graphical sector.
And then of course, we have the choice of the inks themselves and then of course the textiles. So everything should really fit together to get the right quality and the right production in one time.
When we focus on the RIP and we’ll look at the color management and we look at what is on the market today, there are different RIP software systems. There are systems in which you cannot change yourself anything. So you buy a closed system, you buy a printer, you buy an ink and you also buy the RIP software. So in fact, you have very little influence of what you will do. What do you can print, if you were neighbor has been the same software under the same printer, he will be able to print on the same substrate, the same design. So there is no advantage in such a software. You really need a software in which so the software transforms of course, the colors from the design.
You really need to select a software in which you have the choice yourself of choosing your ink set. For example, I have some examples here. You can choose for high-speed and maximum production that you can use twice CMYK ink set. Or you can say, “I really want to be able to make certain specific colors,” and then you will use another set-up. Then you will choose a CMYK and you will select all colors which are different from the colors your neighbor will use. And this is the way to create really a large color gamut. So in this way, you can create more colors. So this is an example of a conventional CMYK and then and lodging the CMYK by using 6 colors so you really enlarge the colors which you can make. For example, if you want to make a very, very bright yellow and you don’t have bright yellow, you will never be able to print it. But in fashion, everything is about color, about attraction; so you really need a very vivid colors. So it’s very important to make the right selection before you start printing to set up the price right ink-set. And their software has to support it. If software doesn’t able you to choose your own colors, then you are quite a limited.
Textile & Pre treatment
And then of course, you have the textile and a textile substrate. And never forget to put the text out of substrate.
Where do we start?
We start conventionally. What does it mean? We first have to select our fiber type. For example, we choose for a silk or which was for a cotton fiber and then we have to pretreat it traditionally. What does it mean? It has to be very white before we start printing. It has to absorb the dye, otherwise we will not get a good equal quality print. So we really need the conventional pretreatment before we can start the digital printing. We also, for example, can choose for either a spin or a filament yarn. We can choose woven or knitted fabric or nonwoven. For a knitted fabric, for example, dimensional stability is very important. If we have something that moves during printing, our print will be deformed; it will not be nice. So we really need dimensional stability. So we have the conventional pretreatment and then we can start the next step.
Within the conventional treatments, we also have, for example, some chemical treatments; desizing of the woven fabric example, bleaching, alkaline treatment for example of the cotton so that it can really absorb a lot of dye. So the conventional treatment should be in any way. And then for the digital printing, one step is added. For every fiber that is printed, we really need a specific treatment. So this is an extra step and then we have the direct printing digital printing step. And afterwards, we have to finish it in a conventional the way. So we really need this extra step. Why? Because otherwise the color will not want to stay with the fiber; we have to fix the color to the fiber. This is really important.
Influence of Pretreatment
So if we look, for example, at some water-based inks, we need the pretreatment. I will show you an overview. This is, for example, polyester fiber that is not pretreated and it starts bleeding very quickly with the direct dispersed dye printed. If we pretreat it, we see 2 things. First of all, we have a lot less bleeding of the product; we have less a lot less bleeding of the ink. And the second thing that we see is that the color changes. So due to the pretreatment that we give, we also can enlarge and optimize the colors that we get. So we need a pretreatment for different things to have the right resolution on certain fibers, for example, polyester fibers, to also fix to dye to the fiber and then to optimize the color space that we will get with a certain ink set. This is, for example, an overview of a polyamide printed with acid dyes. And due to the pretreatment, we have a larger color build up with the same ink set. So it’s really necessary to pretreat in the right way.
Inkjet inks versus Substrates
We also have to make a selection of the inks which are adequate for the substrate. If we look at an ink, then they’re there are different components in the ink. One of the first things is the carrier. If we talk about the carrier it means, “Is it a solvent ink? Is it an Eco solvent ink? A latex ink, a water-based ink?” If we want ink for fashion, we always choose a water-based ink. We cannot use a solvent ink, for example, for a fashion because it’s not good for the skin. We have VOCs coming out so we definitely have to choose for water-based inks, otherwise we will get into problems. Then we also have, for example, or a dye or a pigment in the ink. There is quite a difference. If you use a pigment in the ink, this means that you need a binder. So the binder will make the link between the fiber and between the color pigments. If you use a dye, the dye will enter the fiber and you will have to make a fixation of the dye. So it’s really a different approach. If you use a pigment, you always have a layer on the fabric. So this also means that the wash and fastness properties are less good than, for example, if you use a real dye. And then there are other things and inks such as humectants so that the ink wets the fiber well, etc. So this is just for the behavior of the ink and the ink to… but I will not go into detail for this.
So if we choose the ink, then I have an overview of some of the inks that are used on textiles. The first 3 inks are mainly used for graphical sector for sign, not for fashion applications. And then we have the waterborne inks. And within the waterborne inks, we then, again, have a large variety of possibilities. For example, acid inks, which are used for polyimide, for silk, for wool. We also have, for example, dispersed ink which can be used directly or which can be used by a transfer paper. We have reactive inks. Reactive inks are very good for, for example, cellulosic fibers or and then also for silk or for a polyimide. And then we have the pigments ink. The pigments normally can be used on all fibers. So we get the pigment ink, you can easily print on the polyester cotton, whereas if you have polyester cotton fiber and you want to use other inks, you have to choose twice an ink, which makes the complete procedure very difficult. So the pigment being ink is very interesting because in theory, you can print on all fibers. And then we have latex or veneer, for example. Here, I have more or less the same slides with some applications. For example, if we use a polyamide, we can use it in swimsuits. For example, the company, Van de Velde, will do this but I will go over it quite quickly.
So if we look at some trends, what are the trends? The trends are going to quicker reproduction. What does it mean? If possible, less specific pretreatment for digital printing and then also less after treatment; less after treatment means no steaming, no washing if possible. It’s ink dependent, it’s not always possible. So if we look today, more and more polyester is combined with, for example, elastin fiber. And an elastin fiber is a nasty fiber. You really have a lot of problems during printing. So it might be that fastness properties are lower. In a lot of cases, it’s also combined with microfiber. A microfiber is used for example, for sportswear because it’s very soft. It’s… if you look at a microfiber, I think I have here, the example with one kilogram, we can go around the world. So it’s really a very fine fiber. But you really need a lot of dye, a lot of ink to get a certain color depth. So this is a trend that is coming up in the future. Then so use of more microfibers and then also use of more polyester.
Post treatments of commercial waterborne DP-inks for DDP
If we look at after treatments, I will quickly go over it. But if you use reactive acids disperse, you see there is a lot of time, steaming, rinsing, washing off. So a lot of time, a lot of energy, ecological impact quite high. If you look at the pigments, it’s a lot better. It’s just heat fixation and you don’t need any after washing. So you have a specific pre treatment, you print with the pigment on all fiber combinations that you want to select and then you just have heat fixation. UV is also used in certain cases and it’s also very easy because you don’t have to after wash it neither. But for the pigments anyway, you also needed the pre treatment to get the right color build up. No pre treatment means that the colors are more dull, so it’s really important to introduce a specific pre treatment.
Hardware Printers & Print heads
If we go over to printers and hardware, then this is a little bit an overview of all possibilities. If we go into detail and look at what is used for textiles, then it’s mainly drop on demand techniques, piezo, and valve check techniques; piezo for everything that is flat and value-jet systems for, for example, polyimide carpets.
Development of Print heads
So in the development of the print head, what is the main development but we want to bring more ink on the substrate during firing of the nozzles? For example, wool fiber really needs a lot of ink to get a certain color depth. So this is the challenge to produce print heads that will be able to jet quite larger volumes during the jetting. If we look at the width of the printers, there is also a variety. For example, waterborne printers going from 1 meter 60 to 3 meter 20, which is corresponding with the market. And, for example, if you wanted something for her bedding, you really need something that is already quite wide. If it’s for clothing, 1 meter 60 will be sufficient. Solvent printers can work up to 5 meters. And then we also have some super large printers which can go up to 12 meters. So there is a lot of variety.
Hardware- DP Printers
Also in speed, there is a lot of variety. You can also either use a large format printer which really prints slow or you can go for high productions. So there are all kinds of possibilities. For example, if we look to 2003 or if we look to a smaller large format printer, it will take quite some time to print 30000 square meters. And if we look good today, we can do it within 2 hours. So there is a printer for everybody; for the ones that really want a large production and then also for the ones that they just want smaller high-quality creative production, everybody can make his own choice.
So I will end by giving some advices. These are quality, must be the first priority. It’s very easy to make waste production really. If you don’t have good pretreatment, if the after-treatment is not good, the production is not good. Never compromise on quality. Never underestimate your client or customer. They are really getting more demanding concerning fastness properties, concerning durability, concerning ecologically, and also concerning colors. If they have a certain color in mind, you don’t have to come up with a color that has a Delta-E of 2.5; it will be rejected, it’s not good anymore. Train your operators. That’s a key to success. If they know what will happen with the machine, they will be able to intervene when there is something going wrong. And then, try to have good communication between the designer and the one who should print. So if your designer is someone at home, a customer, explain what he should do to get the right color so that you can really print what he wants. So we want to print by the ER3 philosophy which means, Efficient, Ecological, Economical right, and then, ‘Right the first time’, ‘Right every time’, and ‘Right on time’. So digital technology really makes it possible to be very creative by your own, to make your own and niche market