Page 49 - Print 21 Magazine May-June 2019

Digital Textiles
Left
Market predictions: Smithers Pira
Opposite page
Digital textile printing: market opportunity
Boosting productivity
Improvements in inkjet printing on textiles include innovation in both the machinery and the inks with which they are loaded.
Beginning with the printhead, a number of the latest inkjet printhead product launches and development projects involve the use of thin film piezo silicon Mems fabrication. Mems fabrication in these new piezo printheads enables a much higher nozzle density, smaller drop sizes and much higher firing frequencies, which translates to true native resolutions at 1200dpi that are capable of significantly higher print speeds.
Superior drive electronics technology is now being integrated into newer inkjet systems, simultaneously making them more scalable. The ongoing switch will continue to 2023, from custom development to standardised components using differentiated software programming developed for specific printheads and equipment applications.
Media (fabric/substrate) handling is a key part of any inkjet printing system, and one that is innovating to meet the latest demands in textile production.
Sticky belt style direct-to-
fabric type handling systems are showing significant improvements in automated cleaning and better tracking eliminating major existing problems with media slippage and substrate movement.
Sticky belt style transports that incorporate the appropriate unwind
“Textile printing is a mature global market, but digital textile printing still forms less than five per cent of this global industry, leaving significant market share that can be targeted.”
and post-print collector mechanisms continue to be a good option for direct-to-fabric printing equipment with dedicated to dye-based inks
for dimensionally unstable fabric applications. Other roll-to-roll wide and super-wide format printer models are successfully using a trough style ink capture solution that is acceptable for some direct- to-fabric applications.
Newer inkjet printer designs are factoring in more print production process requirements. Some are jetting primers – or optimisers –
on the substrate only in those areas to be printed, which then need to
be dried with heat and air prior to applying the ink. More air and heat is then applied after the colours to enable spot or flood coating and then more heat and air to provide final drying and fixing. Within this added complexity, the overriding rule is that the faster the system, the more sophisticated the drying/heating/ curing requirements become.
Hybrid direct/sublimation aqueous dispersed dye ink is becoming more popular as higher speed wide-format and grand- format roll-to roll-inkjet textile systems enter commercial print production. With reference to
substrate handling, many of these systems offer the ability to switch back and forth from paper transfer to direct-to-fabric (DTF).
Some consumable suppliers have introduced pre-treatment fluids that help manage the appropriate amount of bleed for two-sided fabric applications, such as flags. These typically higher colourant content ink sets are also benefitting another sub-segment of textile digital printing – display graphics, both frontlit and backlit.
While reactive dye inks still provide excellent colour gamut and performance on natural fabrics such as cotton, aqueous pigment inks are reaching similar colour and performance while being much simpler and environmentally friendly in terms of post-print production.
Cross fertilise
Development in formulations
for these types of inks for other print applications is likely to cross-fertilise the digital textile segment, especially around the interaction of inkjet inks with synthetic substrates and coatings. These aqueous pigmented inks are increasingly formulated for high- speed roll-to-roll production on
a wide variety of fabrics.
The impact of key end-user
and technology factors on future expansion of digital textile printing is examined in detail and quantified in the newly available Smithers Pira study The Future of Digital Textile Printing to 2023. 21
Print21 MARCH/APRIL 2019 49