Special Edition on Textile process...process Special Edition on Textile - Durst news for the science and application of inkjet printing - Issue 96 - May 2013 2Editorial Furthermore,

process Special Edition on Textile - Durst news for the science and application of inkjet printing - Issue 96 - May 2013 1

News• Report on the ISA Exhibition in the USA• Kappa 180 V2 on Tour • Kappa 180 with GOTS-Certification• Durst Inkjet Innovations Days proved to be inspirational and a great success• New Ink QR-Code security labels for Durst Printers

InstallationVGL has invested in more of the latest Durst printer technology including a second Rhotex textile printer

Science & TechnologyThe process steps in inkjet printing

Media & HandlingCloth guiding of textiles in inkjet printing

ApplicationDigital Textiles Made in GermanyTextil Fab´s Durst Kappa 180 highlights the potential of textile production in Germany

processDurst news for the science and application of inkjet printing

96-05-2013

Editorial

Special Edition on Textile

Dear Durst Process reader,

This special edition covers industrial inkjet printing for textiles. This is a very broad field, which frequently gives rise to communication problems. To improve understanding, we will therefore define the two main segments in the digital textile printing industry using our Durst Kappa and Rhotex systems as examples.

Advertising material/soft signageThe Durst Rhotex is designed especially for the advertising market (also known as “soft signage”). Printing takes place using dye sublimation inks on pre-treated materials such as polyester fabric. The end product, which may be a picture, a banner or POS materials, is enjoying increasing popularity in the advertising industry thanks to its high quality and ease of handling and transport. The Rhotex is a proven “work horse” and the production processes are largely standardised.

Genuine textile printing/apparelThe Durst Kappa was designed for “genuine” textile printing such as women’s clothing, fashion and domestic textiles. In these applications, printing takes place using sublimation inks, acid inks or reactive inks on chemical fibres such as viscose, animal fibres such as silk, and natural fibres such as cotton. The production process in this area is very comprehensive, as the textiles must undergo fabric-specific pre- and post-treatments for the digital printing. This calls for specialist know-ledge and further production stages and machines.

In the technical article that follows we want to focus on “genuine” textile printing, also known as “digital textiles”.

Market opportunities for digital textilesIn addition to the numerous benefits associated with digital textile printing, for example cheaper, quicker sample production, reduced setup costs, design freedom, small batches, customised products, etc. there are also many new challenges to overcome. Although the processes for printing on paper, and the handling of conventionalsubstrates, are already well established, they are somewhat more complex for textile printing and the result is critically dependent upon mastery of each individual subdiscipline. This includes:• Pre-treatment chemistry (inkjet pre-treatment, penetration agents)• Texture(s) of the textile substrate• Dye physics in the overall workflow (pre-treatment, printing, dryer, steam/washing process)• Process software including interfaces to merchandise management systems


Editorial

Furthermore, in view of the rapid developments in the market, every company that takes on digital textile printing, regardless of whether they are a newcomer or an established textile manufacturer, must continuously expand their expertise and investments. This includes:• Regular further education measures for staff (subject specific teaching and education opportunities sometimes need to be put in place in advance)• Ongoing and cost based technology and software updates• Digital colour management under difficult conditions (overall workflow)

Textiles mega marketIn 2012, the traditional textile printing sector produced 27 billion square metres.Based upon production volume, the geographic distribution of this was as follows: • China 30%• India 17.5%• Other Asiatic countries 18.8%• Europe, Russia and CIS 11.1 %• America 12.9%• Middle East and Africa 9.7% Analysts expect annual growth of 3%, which would mean production volumes rising to 30-32 billion square metres by 2015. Much more important, however, are the forecasts for digital textile production. These were still 1% in 2012. However, the share is expected to rise to 10% by 2015. (Source SMI, Global Industry Analysis)This rapid growth is made possible by the increased digital production capacity of high performance inkjet systems such as the Durst Kappa 180. The “Kappa” class, for example, defines an average annual output of 600,000 square metres per machine.In the textiles field, digital development is going markedly in the direction of industrial production. In the medium term, the role of smaller machines, like those that are currently the norm in some fields, will dwindle to almost nothing.

70

60

50

40

30

20

10

0 200 500 1000 1500 2000 2500 3000

Producion cost in USD/rm

100

Rotary 12 colors

run lenght (m)

Rotary 10 colors Rotary 8 colors Kappa

ave. runlenght today:+/- 2.000 lm

(fabrics & furnishing)1994 > 3.500


Durst is the front-runner in digitisation Durst has significantly impacted digitisation in many industries and, since 2010, has been working on optimising textile production using inkjet technology. As a specialist in industrial inkjet applications, Durst not only focuses upon technological competence, but also takes into account industry specific factors in the handling of materials.

This is particularly important in textile printing, because this field calls for special pre- and post-treatment, as well as well founded knowledge on the substrate and processes in question. For the digital user, there is a lot to learn at the start, regardless of whether he comes from neighbouring fields such as screen printing and advertising technology or has already printed on textiles in a similar way. But the effort and cost are worth it: companies working with digital textiles are positioning themselves in a growth market in which expertise counts and cannot be easily duplicated. This means that not only are competitive opportunities generated, ecological and social problems are also reduced In comparison to the analogous textile printing, the digital variant reduces energy and water consumption and creates fairer working conditions because qualified and trained staff are needed.

Editorial

Digital textiles are also changing economic conditions by suddenly making it possible to bring textile production back into the “core countries”, as evidenced by the user report from our customer Textil Fab. Large fashion groups such as Intertex/Zara are already defining clear environmental criteria in their calls for tenders and prefer European production sites for their high-end collections. Of course, large volumes will continue to be produced in the Asiatic area in the future, but in addition a lucrative and innovative market is being created in which the demand is growing daily.

Onwards into the markets of the future!The “digital textiles” market is still in its infancy and offers enormous opportunities to the quick and decisive. So let’s conclude with a call for courage! The experts from the Durst textile team can help your company, too, even if you have had no previous contact with the classical textile field. With Durst expertise, our reliable and highly productive technologies and our industry networks can help you to get started in a new, exciting and rewarding sector!

4 days - 2 Weeks/digital vs. analogue

Image ArrangementScreen Design (color separation)Color waysScreen engravingColor kitchen for samplingProducion HW maintenance/checkSample printing/Screen washing(Screen engraving in case of negative sampling)(color kitchen)Treatement of waste inkProducion HW maintenance/checkProduct printingScreen washingTreatement of waste ink

2-3 weeks

Post processing

To sewing processing

Screen textile printing

Design

PreprocessingImage ArrangementSample PrintingImage ArrangementProducion

1-4 days

Post processing

To sewing processing

Inkjet textile printing

Design

Kappa Screen


News

Report on the ISA Exhibition in the USA

The Rho 1030 takes the production curve even further along the large format digital print run spectrum, with production speeds of up to 1000 m2/h. This speed, combined with the printer’s fully automated configuration, gives customers a full production run volume, large format UV inkjet printing capability that meets all their needs for high quality.

The ISA Sign Expo had a slogan, ‘Signs Mean Business’. This years expo did just that, showing the imaging industry the latest in printing solutions and the ability to learn how Durst’s innovative technology will benefit their business.

The ISA International Sign Expo is a premier trade show serving the sign and visual communications industry. Produced by the International Sign Association, the show provides the largest gathering of sign industry professionals in the United States with the aim of conducting business, networking and education.

Durst was the centre of attention by featuring the most innovative products on the market. The Durst booth generated constant traffic from the show’s attendees, who had the opportunity to see first hand, the Rho P10 320R with Variodrop technology, the fastest 10 picolitre UV roll printer in its class. Capturing the attention of everyone was the announcement of the evolution to the Rho 1000 series of printers with the new Rho 1012 and Rho 1030. Designed with unique capabilities and a clear focus on efficient workflow solutions, the Rho 1012 and Rho 1030 redefine the concept of flexibility with unrivalled print quality. The latest additions to the Rho 1000 series, set the standard for high end industrial inkjet productivity that can be tailored to each customer‘s requirements.

The Rho 1012 offers the highest print quality available, featuring the new 12 picolitre Durst Quadro® Array printhead technology, enabling it to print at speeds of up to 490 m2/h. The small drop technology implemented represents unrivalled quality at these print speeds, giving the user the ability to meet the quality and volume requirements normally reserved for high-end lithographic applications.


News

Durst presents the new Kappa 180 V2 and other innovations for the textile production

Kappa 180 V2 on Tour

The textile supply chain is an international market and so Durst presents the latest additions to its digital textile print portfolio at various international trade fairs. For the Eastern European market, Durst presents itself as a Gold-Sponsor at the International Federation of Textile Chemists and Colorists (IFATCC) Congress in Budapest/Hungary. The Euro-Asian market will be addressed in Istanbul/Turkey, where Durst exhibits its latest developments at the International Textile Machinery (ITM) 2013 from 29. May – 01. June. This is followed by the ShanghaiTex, a trade fair for the Asian market from 10.-13. June.

The focus of attention is the new High Performance Production Machine Kappa 180 V2. Since the introduction of the Kappa 180 at the ITMA 2011, Durst has further developed the inkjet technology for different textile applications, in close cooperation with its customers. The Kappa 180 V2 now features the latest V2 printhead technology, where the colors are aligned symmetrically (opposing and mirrored) on the 8-channel-printheads. This ensures precise application of color, even for a bi-directional print process. It also eliminates streaking, as is common with conventional, asymmetrically aligned printheads at high speed.Regardless of the print direction, the color channel is always in a perfect position to optimize the reproduction of designs with intricate color gradation or delicate patterns. The color conformity across the entire print width is maintained, without reducing production speed. Together with the Kappa 180 V2, Durst also offers a powerful dryer-unit, specially developed for knitwear. With the reformulated and GOTS-certified reactive ink system, Durst expands its application of reactive inks to include silk and polyamide. This enables the production of cotton, linen, viscose, silk, polyamide and polyester, all on the same machine. In addition to its flexibility, the Durst Kappa 180 V2 provides an industrial production capacity of 580m²/ hour and a maximum print quality of 1000 dpi.

Kappa 180 with GOTS-Certification

Digital Inkjet Technology with eco-friendly Reactive Inks for a sustainable textile production

Durst has received the prestigious GOTS-Certification for its Reactive Ink System (Kappa Ink R). According to Greenpeace*, the Global Organic Textile Standard (GOTS) is the most demanding seal of approval in the complete textile production chain. The GOTS is the only textile standard to define stringent environmental guidelines and requirements for humane working conditions – from the cultivation of the fabrics, to the finished product. Only textiles, which contain at least 70% of controlled, organically grown natural fibers, are eligible for certification. All chemicals, as well as dyes and additives must satisfy all criteria regarding their environmental and toxicological impact. Durst developed the Kappa Ink R especially for the Digital High Volume Printer Kappa 180, to print on pure or cotton mixtures with absolutely eco-friendly, water-based ink systems.

´Sustainability is the central issue in the textile industry. The end customer demands it, and it is an important aspect of choice for the supply chain ,̀ says Christoph Gamper, designated CEO of the Durst Group. ´The GOTS-Certification underlines our aspiration to furnish the textile industry with ´green` technology and genuine value creation.̀

Durst´s Kappa 180, the Digital High Volume Printer, is a real alternative to the traditional flatbed screen printers. With its print speed of 580 sqm/hour (300 running meters), and its outstanding print quality (1000 x 600 dpi), the Kappa represents the top standard of digital textile printing. In addition to its impressive technical specifications, the Durst Kappa 180 creates true economical and ecological value, compared with traditional printing methods, because it reduces water- and power consumption. At the same time, it provides full flexibility for the customer, because the inkjet technology allows on-demand production at the highest print quality, unlimited design- and color variations and quick reproductions. Durst´s in-house development of Kappa Inks for inkjet technology is concepted specifically for textile printing. These inks allow for printing with absolutely eco-friendly, water-based dispersion-, reactive or acid ink systems on a variety of textile fibers.

*Greenpeace: ´An environmental assessment of textile labels`


News

Durst Inkjet Innovations Days proved to be inspirational and a great success

Productivity was the common factor with all the new products demonstrated by Durst Firstly, there was the introduction to new machines in the Durst’s flagship range, the Rho 1000 Series, which included both the new Rho 1012 and the Rho 1030. The Rho 1012 is the most productive 12 picolitre flatbed printer in its class capable of printing up to 490 m² per hour at 1000 dpi. The stunning quality is idea for “close up” viewing of backlits and POS, for example, as the delegates were able to see. The Rho 1030 is the world’s fasted UV inkjet flatbed and capable of printing up to 1000 m² per hour. The machine was demonstrated as a fully automated line with auto feed and stacking. Several visitors actually held stop watches to confirm both the Rho 1012’s and 1030’s actual speed!

With the emphasis still on productivity, visitors were able to see Durst Variodrop technology which is the latest development in the highly successful Rho P10 Series of printers. The Rho P10 printers are the first industrial level UV inkjets to feature 10 picolitre ink drops. The new Variodrop technology provides up to 25% increase in output for all the Rho P10 models. It also solves the inherent problems which can jeopardise the quality of printing with greyscale ink technology.

As well as learning about some of the future projects currently in progress at Durst, there was a new ink development entitled “Premium White HD Set” for printing on the Rho P10 Series. This new white ink provides even better coverage whilst maintaining high print speeds.

Michael Lackner, head of marketing for Durst, said: “We are delighted by the response we have received for the event. We were fully subscribed with guests and the response to the programme met with universal approval. Although this was intended as a one-off event, I do believe that it is something that could become an annual part of the Durst calendar.”

Held in the Durst factory at Lienz on the 17th and 18th April, Durst’s two day event, entitled “New and practical inkjet applications through knowledge and technology”, was voted by the full house of guests to be both inspirational and most enjoyable.

It was attended by over 120 key customers from all over Europe and a few select journalists. The programme included a series of lively and entertaining lectures by some of the industry’s leading authorities on digital and inkjet printing. These highly popular lectures covered such diverse subjects as, “The Future of Large Format Inkjet”, “Web-to-Print”, “New Business Models” and “Process Standard Digital”. It was also an opportunity to see practical demonstrations of Durst’s latest technological innovations, which featured the European launch of Durst’s latest additions to its range of inkjet printers. Included in the launch were two new Rho 1000 printers, technological advances to the highly popular Rho P10 Series and the opportunity to learn about the new Process Standard Digital.

Where next for inkjet printing?After a welcoming address by Dr Richard Piock, CEO of Durst Phototecknik, the right tone was set for the English language event by Dr Markus Lorenz, Partner and Managing Director of The Boston Consulting Group, Munich, with his presentation entitled “The future of large format digital printing: The Need to Innovate in an Innovative Environment”. Following this informative discourse on broad market trends and prospects for the future, Matteo Rigamonti, President of the Italian Web-to-Print pioneer Pixartprinting, chose a very personal approach for his presentation which proved to be highly entertaining and provocative, “We are only doing it for the money” was one of his propositions. Bernd Payer from the PKF Consulting GmbH led his own successful printing company in Austria for 15 years before he started working as a consultant. “A machine is an important resource for a business model – but is not a business model itself”, was one piece of food for thought from this experienced businessman. Process Standard Digital was presented by Berthold Oberhollenzer, of Fogra, Germany, under the heading of “Printing the expected with PSD”. Unlike offset printing, digital printing has too many media variables to copy the existing ISO Printing Standard. Fogra has based the PSD on actual quality of print. The end result is that a quality standard can be followed by printers and easily checked to see where any fault might lie.


News

New Ink QR-Code security labels for Durst Printers

Durst has launched its new QR-Code (Quick Response Code) security labels for ink cubitainers. With the new QR-Code, manual data entry of ink batch numbers, color, refill date, ink manufacturing- and expiry date is no longer necessary. This new feature prevents expired inks from being refilled resp. warning the operator on expired inks in the tanks due to no use of it for a long period.Especially some colors –e.g. violet, orange or grey, sometimes also white, which are used rare, could create problems in the printheads because of being expired. Expired inks show either sedimentation or agglomeration of pigments, also they can show reduced curing behavior. For only this reason – not as code for securing the use of original inks - the QR-Code has been created for all of Durst’s printing devices.

In order to read the QR-Code, each Durst Printer requires the latest User Software Version 2.6 Rev. 6 (e.g. for Rho Printer) or later versions and the new QR-Code Reader. The QR-Code Reader is directly con-nected to the Printer Workstation via USB cable. By reading the QR-Code security label on the ink cubitainer, before filling the cubitainer, the ink information is decoded and transferred directly to the Durst Printer User Software and added to the existing list of refilled ink under Ink Batch Tracking in the User Software. Additional comments can still be added manually if desired.

All currently installed Durst Printers can be upgraded with the Durst QR-Code Retrofit Kit, which is now optionally available and includes hard- and software. The following Durst Printers can take advantage of this new feature: Omega 1 and 2, Rho Roll to Roll and Flatbed Printers, Rhotex 320, Kappa 180 and Tau 150 and Tau 330 Label Press.

The new QR-Code security labels will appear on all Ink Cubitainers shipped from Q2/2013 on.

QR-Code Description The QR-Code contains the following information.• Ink type and batch number• Color• Ink description• Production date and expiry date• Ink quantity [litre or kg] • Durst internal code number

Example: Screen shot Rho 320R HS User Software V2.6 Rev. 6


Installation

VGL has invested in more of the latest Durst printer technology including a second Rhotex textile printer

Both the Rho P10 320R and the two Rhotex 320’s are housed in VGL’s new 26,000 sq ft factory which is just five minutes from the other main site and head office. The new factory is used for both digital flatbed and roll to roll. The company has one other site in Reading which is used for screen printing.

The two new printers from Durst join four other Durst UV roll to roll inkjets. “We have been very pleased with Durst printers,” commented Michael Ayerst. “”Added to which Durst has provided an excellent service to us from the outset. In the unlikely event of a problem occurring with a machine Durst are very quick to fix the fault, ensuring that the machine suffers as little downtime as possible.”

“We have gradually replaced all our old roll to roll equipment with Durst machines. These include a Rho 160R (using 3M Scotchprint consumables), a Rho 320R, a Rho 500R and a Rhotex 320 textile printer. We are already very impressed by the Rho P10 320R, which stands alone in the market for print quality. Typically we use it for jobs that require the highest possible quality such as backlits and Duratrans type products.”

“Textiles are a major growth area for us and potentially the whole market. We first installed an Artistri 2020 when we were limited by space. Now, with our new factory, we have been able to install a Rhotex which has helped us continue to expand our textile printing. The Rhotex offers fantastic quality at an industrial speed. Being 3.2 m wide has also been a benefit.”

Already the Rhotex is kept extremely busy and that is why we have ordered another. As already mentioned, it is very important for us to maintain a level of capacity as well as being able to meet the continued growth in the demand for printing on textiles. In the UK we have been slow to develop this area whereas in Europe textiles are still far more widely used. The benefits are many including a 60% reduction intransport costs, easily interchangeable graphics i.e. no large boards have to be erected and if a textile banner falls it just floats to the ground! Very importantly, textiles are environmentally friendly and recyclable.”

“As a company we are extremely environmentally conscious. We are phasing out our solvent printers although we have some arge customers who still use solvent printed material but they are gradually moving away from it. Furthermore, we are constantly looking for ways to reduce our carbon footprint; printing on textiles helps in the matter.”

“One application that has really caught on is the use of displays printed on textiles and mounted into frames. We use a system manufactured in Holland and it has had a major effect on much of our retail display work. Instead of sending out a team to install the latest promotion we just send the designs printed on textiles and anyone can install the new graphics into an existing frame. Short runs and personalisation are becoming a large part of promotional material. Regional and even local campaigns instead of national promotions are becoming a significant part of the industry. For that you have to be able to respond quickly.”

Recently VGL, based in Reading, UK, installed a Rho P10 320R, the first in the UK, and has now added a second Rhotex 320 to its impressive stable of large format printing equipment. Equally impressive is the company’s list of clients which include many large national brands. The company produces a wide range of large format display items including promotional, retail and architectural graphics as well as outdoor media and vehicle graphics.

“We have always invested in the latest and best technology,” said Michael Ayerst, Managing Director and co-owner of the family run business. “Consistent high quality is vitally important for our customers. Over the last three years we have seen a lot of our competitors standing still, whereas we have continued to invest and expand and our turnover has grown from £8m in 2008 to £13m in 2012. Not only is the highest quality of print at a competitive cost very important, but also the ability to maintain capacity. Customers want reliable and fast turnaround of their work from a supplier they can depend on. Durst has been key to our success ensuring that our customers receive the highest level of quality, consistently.”


Installation

VGL prides itself on its innovative approach to both technology and value added products. One such product is “Surface View” image reproduction. VGL holds a unique collection of high quality images which designers and architects can use to make beautiful bespoke interiors. The images can be used as attractive and original wallpaper designs, for example, or as giant images for museums, or printed onto clear film for window decoration. “The choice is unlimited and we support the product with a full installation service,” explained Michael Ayerst. “People from all round the world love ‘Surface View’ and, in fact, several articles have been written about it in the national press, the latest being the FT. Now that we have established an on-line ordering and payment system the business has really taken off and we receive a constant level of business through it. One benefit of the system is that it can also instigate discussions about other areas of our work with potentially new customers.”

For more information on Surface view visit: www.surfaceview.co.uk

About VGLVGL is a family business, founded as a traditional screen printing company in 1976 by Ted Ayerst, father of Michael and Simon. Initially VGL produced self adhesive decals primarily for the signage and automotive industries. In the early 1980s the company introduced the first computer aided sign cutting machine to the UK and was one of the first to be involved in the development of digital print during the 1990s. From this early investment, VGL has been a technical based digital and screen printer committed to investing in the best technology. Today, VGL uses both screen and digital printing to achieve the best and most cost efficient results, often combining the two disciplines in one job.

For more information on VGL, telephone: 0118 922 1300 or visit www.vgl.co.uk


Science & Technology

The process steps in inkjet printing

Disperse

m

m

w - ml

m

m

m

Fibre

Cotton (CO)

Linen, Flax (LI)

Polyamide (PA 6, PA 6.6)

Polyester

Silk (SE)

Viscose (CV, CLY, CU)

Wool (WV,WO)

Pigment

l

l

m

m

w

w

w

Reactive

l

l

w - mm

l

l

l

Acid

m

m

l

m

l

m

l

Class of dye

suitablenot entirely suitablenot suitable

Strengths and weaknesses of the class of dye

l

w

m

Disperse

l - wl - ml - wl

l

l

l

Fibre

Brilliance

Light fastness

Gamut

Wet fastness

Rubbing fastness

Sweat resistance

Wash resistance

Pigment

w - m

l - mm

l

m

l - wl - m

Reactive

l - w w - ml - wl - wl - w w - ml

Acid

l - wl - ml

w - ml - w w - m w - m

Class of dye

goodaveragepoor

l

w

m

What inkjet printer doesn’t dream of the ideal printing technology? From a process point of view, it should be as simple as pigment printing and as brilliant as reactive printing, all of course with the highest level of fastness and with the largest possible colour space!However, the variety of textile fibres, in conjunction with the wide range of areas of application, forces us to look at the various classes of dyes and their process variants.

Overview of the most important fibres in ink-jet printing and allocation of the class of dye

Functional mechanisms of the classes of dyesThe following brief descriptions of the classes of dye explain the overview given above as a guide.

Disperse dyesDisperse dyes are water insoluble pigments. These very finely ground pigments are finely distributed in the inks and they should not agglutinate or settle. These dye particles have no affinity to the water but they do have to the likewise water repellent polyester fibre. The dye is set using high temperatures, either hot air or by using high temperature steam. During the setting process, these dye pigments penetrate into the fibre. The fibre itself is, in effect, the solvent for the dye. This then explains the high level of fastness of the dyes. The dye is protected by the fibre itself. The fibre cannot offer any protection in terms of light fastness; this is only dependent on the stability of the dye pigments.



Pigment dyesPigment dyes, like disperse dyes, are water insoluble colour pigments. These particles are stuck onto the fibre. To achieve sufficient covering power, these particles must be kept as large as possible. This is what is behind the well known problems with the running characteristics with inkjet printers. The size of the particles is one of the causes of the low brilliance of the colours.Plastic components are used to set the pigments and after being applied to the fibre are synthesised to the finished plastics. This is done, using either dry heat or UV light, depending on the system used. The amount of binder needed to set the dyes on textiles is considerable. The amount of such chemistry to be accommodated in the inks is limited. The running characteristics of the inks deteriorate dramatically as the concentration increases. This amount is usually nowhere near sufficient for textiles and often therefore more binder has to be applied in another step. This in turn has a negative influence on the grip (feel) of the products. The dyes are glued onto the fibre surface and, as a result, all fastness levels, in which there are mechanics, show poor values. On polyester and polyamide, the adhesion is particularly poor. The binders either do not stick to these fibres or only very poorly.

Reactive dyesAs the name says, these dyes react chemically with the fibres. The colours are extremely brilliant, as each dye molecule is separate. The wash resistance is very good due to the chemical bond with the fibre. These dyes are very sensitive to light and chemical influences (for example chlorine). Pre-treatment of the fibres (CO, LI, CV, SE, WV) is very critical. The dyes must have good access into the inside of the fibre. As a rule, these dyes are set using saturated steam at 102°C.

Acid dyesAcid dyes are usually used in combination with metal complex dyes. The acid dyes are for the brilliant colours and the metal complex for lightfast colours. These dyes are bonded to the fibre in a physical way. The dye has a high affinity to the fibres. This form of bond is nowhere as stable as a chemical bond. This is also the cause of the poorer levels of fastness, in which water is involved and or high washing temperatures are able to dissolve these bonds. Good access to the inside of the fibre must be guaranteed, as in the reactive dyes, if good setting is to be guaranteed.

Process technologyTraditional print pre-treatment, which is not to be confused with the special pre-treatment for inkjet printing, is the basis for the best print results.

• Traditional pre-treatment is required for any type of printing, both for traditional screen printing and as a basis for inkjet printing on textiles.• Inkjet pre-treatment is required in addition to the process step above for the inkjet print.

However, in the traditional pre-treatment, the bar has to be set very high. In inkjet printing extremely small dye volumes are applied in some cases. They react accordingly sensitively to disruptive factors.

Special pre-treatment is necessary beforehand when it comes to printing textile fabrics with inkjet printers, even with pigment print.



Functions and components of inkjet pre-treatment (VBH)Generally softened water should be used to set the VBH liquids. Untreated water always contains various dissolved salts (water hardness) and under certain circumstances multivalent metal ions. Their concentrations vary markedly, depending on the location. These substances can cause various problems.

1. Controlling the print imageThe individual drop of ink should neither expand in the width nor sink down into the inside of the textile. Thickeners are used for this and a difference is made between native and synthetic products. The type of thickener used depends on the class of dye and the process technology applied.

Effect of the thickener

without

best

too much

poor print levellow depth of colour

well-defined print imagemaximum depth of colour

individual dots get lostloss of depth of coloursusceptible to abrasion

2. Chemistry for setting the dyesEvery class of dye has its own very specific requirements if it is to be set on the fibre. In addition, the machine must be able to absorb any interference. More detail will be provided on these components.

3. AidsThis group includes those additives that have nothing to do with the actual setting processes. These are for example surfactants or preserving agents for the primer.

Example: Inkjet pre-treatment on cotton

Traditional pre-treatmentAlong with any contamination on the fibre and its natural waxes, projecting fibres and any aids from the spinning, weaving or knitting processes must be removed. Subsequent bleaching destroys the natural dyes of the fibre and pre-treatment usually ends with this due to the cost factor. To achieve the best conditions for the setting of dyes, the cloth should be caustified (treatment with caustic soda solution), or preferably mercerized (treatment with strong caustic soda solution under longitudinal tension). The fibre swells in these processes. The dye setting is enhanced, the shine of the colours heightened.

Microscopic fibre cross sections of CO

Non-mercerized Source: Lexicon for textile finishing

mercerized



Cotton is printed exclusively with reactive dyesVBH components chemistryAlkali: is required for settingOxidant: protects the dye from reductive influencesUrea: for the moisture balance on steaming

SettingThe best results are achieved using saturated steam setting at 102°C for 10 minutes. This process is very demanding.

Influence of the steaming conditions on how the colour turns out

Wedge 3

excellent

poorWedge 1

Wedge 2

excellent

poor

excellent

poor

Mercerized cotton is the only fibre that can also be set with hot air.

WashingAs hot as possible to cleanly remove the thickener, the chemistry and any dye not stuck to the fibre. The fabric should be boiled for at least 8–10 min.


Media & Handling

Cloth guiding of textiles in inkjet printing

The printing blanket represents the most important part of the cloth guiding elements for textile printing. It was the initial part required to make it possible to print all textile substrates. The first inkjet printers used for textiles were slightly modified paper printers and these units were built for stable, closed substrates. As a result, only tightly woven articles could be printed. All other items had to be glued (bonded) onto a stable fabric or a support paper beforehand. Only with the increasing production capacity of the systems was the high cost represented by the printing blanket financially justifiable.

Why the printing blanket is so important and what purpose it serves

1. Excess ink that ends up between the threads must be removed by the cloth and to a large extent this prevents the printing being smeared. In addition to preventing the emergence of ghost drops when the textile is struck through, the area around the machine is kept clean.

Cloth structure

openclosed

2. The fabric glued onto the printing blanket is prevented from moving during the printing process. This is a basic requirement for accurate printing.

All textiles are movable. They are built from interlocked threads or woven goods, or interlaced threads or knitted fabrics. There are no fixed connections and the threads are also always arc-shaped.

Knitted fabric Cross section woven textile

Knitted fabric is by its structure considerably more movable and more unstable in its dimension.If a knitted fabric is exposed to stretching, the stitches become distorted. If it is stretched lengthwise, it shrinks in width and vice versa.

Effects of 10% stretching on the mesh structure

lengthwise crosswise


Media & Handling

Even very minor forces are enough to cause these types of distortions, therefore to print accurately on these items, it is necessary to fix the cloth onto the printing blanket. Without the printing blanket, the cloth would also start to oscillate when it is fed onto the printing machine.

Every textile material strives to balance its internal stresses and this happens most easily when it its wet.If a dry textile is dampened, which is what happens in printing, any stresses in the material are released and the cloth moves.

In this process, the fibrous material used plays an important role alongside the fabric structure. Fibres that absorb moisture swell. All natural fibres plus cellulosic regenerated fibres exhibit this behaviour. The intensity of the process varies from fibre to fibre. Viscose fibres have the highest swell values. As a result, very tightly woven viscose items, for example, may become distorted in an undulating manner with printing, if they are not glued onto the printing blanket.

The items with elastane fibres represent a widespread special case. In these substrates, a specific pre-stress is built up in the material. This pre-stress also exists in materials to be printed. If the material is soaked by the ink, this stress is released and the cloth shrinks, i.e. it contracts. It is therefore essential to hold the cloth in position during the printing process.

Orientated overview of how textiles move

TendencyTextile

Woven textile of polyamide, polyester

Woven textile of cotton

Woven textile of viscose

Woven textile of cotton with elastane

Woven textile of cotton with elastane

Knitted fabric of polyamide, polyester

Knitted fabric of cotton

Knitted fabric of viscose

Knitted fabric cotton with elastane

Knitted fabric viscose with elastane

Shrinkage

0 %

~ - 20 %

There are stresses in material for most of items to be printed.

Shrinking lengthwise practically always happens with the exception of woven items made of polyamide and polyester. Technically, it is virtually impossible to eliminate this lengthwise shrinking. In inkjet printing, these types of lengthwise contractions can be intercepted relatively easily by spreading the design accordingly.

It is easier to control the width of the item. The cloth is presented for printing as per its finished width. However, there are nearly always stresses, as the items are not yet fully finished.Items with elastane content are even supposed to be pre-stressed. However, it moves in a range of 5–8 percent. If they were not stuck tight during the printing process, they would shrink and printing would not be possible.


Application

Digital Textiles Made in Germany

Germany´s importance as a producer of textiles has continuously declined in the past few decades. In the last few years however, the re-emerging German textile industry has identified and occupied several niches and is currently a key producer of Technical Textiles for the automotive- and electrical industry. The first impulses to reanimate the production of clothing can even be observed. These impulses are not created by the established producers, but stem from newcomers, looking for their chance to enter the market. The Teningen based company Textil Fab illustrates this development. It was founded as a prepress producer in 1989 and in 2005 changed its entire business domain to digital textile production.

´We had observed the consolidation in the print industry for 18 years, and actually found our new business segment by chance,̀ says Andreas Uhlmann, Managing Director of Textil Fab.Because of the ongoing competition and the pricing battle in his core business, Uhlmann decided to diversify his business and to prepare the necessary structures for a relocation to Spain. So in 2002, he founded Cancun Fashion, a producer of Bikinis and Beachwear. Today, Cancun Fashion is the main character in Textil Fab´s story of success in digital textile production. Cancun Fashion‘s ´KombiKini` brand presents a collection of Bikini-Sets and Beachwear, where customers‘ sizes and styles can be matched and combined to individual taste at the online-shop.The option to combine-as-you-wish quickly became very popular with the customers. Soon after, Cancun Fashion was faced with difficult issues regarding the print of the design samples. If it wasn‘t the color that was impossible to match, it was often a problem finding a supplier who would print the textiles in short run productions or who would sell it by the meter.In 2005, Uhlmann reacted to this situation and completely stopped his prepress production. He invested the proceeds from selling the paper print machines in several small digital textile printers, manufactured by d.gen, Mimaki and Roland. His considerations were not only focused on producing his own collections, but also on providing the facilities for other producers´ sample prints and short runs.

´Those were tough times, because we did have know-how of digital print processes, but still, we had underestimated the challenge of handling different textile fabrics. Until the problems were solved, we resorted to producing banner and promotional media ,̀ Uhlmann reflects with mixed emotions on the good but hard early days.

In order to gain control of the processes involved in digital textile production and to ensure a high and constant level of quality, Textil Fab invested in an integrated SETeMa Fixation-Washer-Dryer Unit and tested innovative chemical formulas for the pre-treatment of different textiles.

´The result of that learning process was, that afterwards nobody had an edge on us in either, the chemical composition for the pre-treat-ment nor on the operations of a textile printer circuit board ,̀ reports Uhlmann, who taught himself the tricks of the trade.

For contract print jobs, Textil Fab have set up an online-shop to offer exactly, what Uhlmann had looked for and not been able to locate: digital textile print materials sold by the meter, minimum order – three running meters. Quickly, the news of digital short runs spread among designers and producers, with the customer base growing accordingly. The location benefits of the Franco/German/Swiss border triangle helped the business to really take off.

But as textile isn‘t paper, the company had to undergo a thorough learning process in the pre- and post processing of print materials.

Textil Fab´s Durst Kappa 180 highlights the potential of textile production in Germany


Application

In 2012, the Kappa 180 was finally installed at Textil Fab in Teningen. Initially, the company produced cotton and mixed fabrics for Dutch, Austrian and CIS (Community of Independent States, formerly USSR) customers. Early 2013, Textil Fab field-tested a GOTS-certified ink system in cooperation with Durst, the industrial inkjet specialist. This system uses reactive inks and permits printing on silk and polyamide.

´The advancement and implementation of the reactive ink system to replace conventional acid applications affirms our decision for Durst as our technology partner. We are now able to access new markets, using the same print machine, but with the reactive inks, producing a higher color fastness compared to acid ink systems. Simply, the next level of quality!`

´Due to this unique position we were able to increase production to maximum output shortly after. To further expand and offer our services across Europe, we had to invest in an industrial production unit.̀

To find the best possible solution, Textil Fab analyzed systems by Zimmer, MS and Reggiani regarding their print quality, production speed and value for money. The Durst Kappa 180, introduced at the ITMA 2011 decided the race. The purpose-built Durst Quadro Array printhead technology, equipped with a silicon-cured nozzle plate, convinced Uhlmann, who himself is an expert in print technology.

´The printheads are the most fragile elements of the print machines.In that respect, Durst‘s engineering capacity was far superior to that of other manufacturers. The Kappa 180 meets all our criteria regarding its printhead technology, its reliability, speed and print quality.̀

The successful cooperation of both companies in the GOTS field-test was extended to include neon colors, with a focus on developing Fashion Beachwear.

While still being positioned in the market as a textile finisher for small runs, Textil Fab now has the Kappa 180, with enough industrial capacity and flexibility to produce cotton, linen, viscose, polyamide and polyester all on a single print machine. Digital textile production has created a niche market with competitive production costs for Textil Fab, right in the heart of Europe.

´Digital textile print has similar costs, wherever you are located, because direct labor costs are much lower compared to traditional methods. We are close to our customer base, there are no customs duties to be paid and transport costs are moderate so we can provide a straightforward service. The customer gets a high quality print, virtually just around the corner, in the quantity he requires and the requested delivery period.̀

https://www.youtube.com/watch?v=VsOAN4Ydz4g


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