Digital Textile Printing Inks, the Basics

DigitDigital printing on textiles has opened the door for a new level of accessibility for designers, as well as consumers. Technology is improving quickly and customization is only going to become more and more common. To best understand this technology, it’s helpful to know as much as possible about the materials and processes used. There are several different types of inks and techniques for digitally printing textiles, and each has its own set of pros and cons.

There are 4 standard types of digital textile printing inks.

• Dye sublimation inks are primarily for synthetic fibers and utilize a paper print and heat transfer process. This technology allows the use of synthetic materials since the colorants bond to the substrate under heat and pressure. This process infuses the colorants at the molecular level. 
  
• Reactive dye inks are popular in fashion applications. The dye molecules have “reactive” sites that physically bond with natural substrates like cotton. Essentially, the dye is incorporated into the fiber. As a result, it yields high rub-fastness. Usage of reactive dye inks is a notoriously wasteful process due to the heavy post-processing required. However, they produce the most visually appealing products.
  
• Acid dye inks require similar heavy post-processing. They are used for more niche cellulosic substrates like wools, silk, and cashmere.  
  
• Finally, there are up-and-coming pigment inks. These ultimately aim to solve a lot of the waste issues. Pigment inks work with virtually any type of fiber, although some fibers require an ink-receptive pretreatment. Pigments are an interesting technical challenge because the pigment particles sit on top of the substrate. This makes it harder to achieve comparable fastness properties without properly tailored pre-treat chemicals. However, at Fujifilm we think we can get pretty close with our newer generations of inks. Pigment inks perform particularly well in the home-furnishing/decor segments due to their ability to meet lightfastness and durability requirements. They are slowly moving into fashion as manufacturers realize the value. 

These digital textile printing inks have different properties in regards to performance.

Whether digital textile printing inks are safe enough to be close to the skin ultimately depends on their exact ink chemistry. In general, most common products are safe. Globally Whether digital textile printing inks are safe enough to be close to the skin ultimately depends on their exact ink chemistry. Globally recognized third party organizations provide certification or other verification services at all levels of the supply chain to ensure consumer safety and environmental sustainability, such as OEKO-TEX ®, Global Organic Textile Standard (GOTS), and bluesign ®, to name a few.  Additionally, some larger brands leverage their own “regulations” that their suppliers must abide by. Several Fujifilm customers use our array of water-based pigment inks to print various personal care products. During the COVID-19 pandemic, some customers are using these inks to print protective face masks. 

The lightfastness of the inks depends on the exact colorant and ink chemistry. In general, textile inks have a fairly high lightfastness standard compared to other applications. Dye sublimation ink products are typically subjected to the more taxing outdoor applications such as outdoor signage and billboards. However, pigment inks aim to supplant many of these applications. Fujifilm’s Pro-Jet™ TX400 series of pigmented inks score 7 out of 8 on the Blue Wool Scale permanence measurement standard, according to ISO105-B02 test methods. 

Crock fastness (aka rub fastness, color fastness) is an important factor to consider in the application and type of ink chemistry used. Most textiles will be subject to some form of abrasion throughout their lifetime. Generally, a higher crock fastness will correlate to longer image life on the product.

As with most textile production, there are environmental impacts.

In a global market, consumers are growing increasingly sensitive toward sustainability issues and solutions. Unfortunately, textiles as a whole continue to rank among the worst industries in many impact areas. While the issues are not limited to any specific digital textile printing inks technology, reactive ink printing commonly draws attention as being environmentally unfriendly, especially in terms of water consumption. Printers around the world are under increasing governmental pressure to reduce waste water from these processes. The exact amount of waste depends on the individual process and products produced, but water usages approaching 1 metric ton of water consumed per 1 kg textile produced are not uncommon. Taking advantage of digital pigment textile inks are one way to go about significantly reducing water waste. Pigment inks only need to dry to fix to the substrate, and thus, do not require any post-print washing. 

Print-on-demand technology is trending across many industries.

Print-on-demand technology fits perfectly with evolving consumer-driven trends. We are all familiar with the rise of online retail and the shortening of supply chains. Mass customization and targeted experiences have become a regular part of life. Textile manufacturers will need to keep up with this demand. These trends will only expand and print-on-demand is best poised to deliver solutions to that goal. End customers will be able to have custom prints to fit their needs and wants, whether in fashion, home textile, or home décor. 

There are different business models for the supply of printing systems and consumable products. Many printing equipment OEMs are moving to “closed systems.” This means the OEM sells not only the printer but can also restrict the end user to a specific set of options for software, pre and post-treat equipment, and consumables. Turnkey solutions like this can certainly be useful for new users. Others users may opt to retain more control over the supply of their materials, and especially the inks, and so they use the “open system” approach. Fujifilm offers textile and other inks for a number of printers, printheads, and end-use applications. 

This post was written by guest bloggers: Jillian Sloan, Key Account Manager and Eric Kurtz, Aqueous Inks Product Manager at Fujifilm Ink Solutions Group.