Ink & Ink Dispensers
Digital inks for label printing: Formulation innovation meets performance demands
By Simon Daplyn, product & marketing manager, digital, Sun Chemical D
igital printing has transformed the label industry by enabling short runs, rapid changeovers and high levels of customisation. As brand owners demand
greater fl exibility and converters look to improve productivity, digital ink technologies, particularly UV and UV LED inkjet have become central to modern label production. Behind this progress lies a critical enabler: advanced ink formulation.
Today’s industrial inkjet printheads are capable of resolutions up to 1200 dpi at production speeds exceeding 100 metres per minute. Achieving this combination of speed and precision places stringent demands on ink performance. Inks must jet reliably through ever-smaller nozzle sizes, form stable droplets at high fi ring frequencies and cure rapidly, all without compromising print durability or regulatory compliance.
BALANCING VISCOSITY AND REACTIVITY Low viscosity is essential for reliable jetting in high-frequency printheads, but achieving this in UV- curable systems presents a formulation challenge. Ink chemists often turn to lower molecular weight monomers to reduce viscosity, yet these smaller molecules typically have lower functionality, meaning fewer reactive sites during polymerisation. The result can be reduced curing effi ciency.
To overcome this, formulators carefully balance monomer selection with photoinitiator systems and high-solvency components, ensuring inks cure fully at press speeds while remaining compatible with printhead requirements. This fi ne-tuning is critical to maintaining adhesion, chemical resistance and rub durability on a wide range of label substrates.
PRINT RELIABILITY AND OPEN TIME At high resolutions and small drop sizes, ink stability becomes equally important. One key parameter is “open time”, the period during which ink can remain in the printhead without drying, clogging, or degrading printing performance. Advances in formulation now allow open times exceeding 60 minutes, signifi cantly reducing press stoppages and improving overall equipment eff ectiveness. Another technical challenge is satellite formation, where tiny secondary droplets disrupt image quality and contaminate printhead faceplates. High-purity pigments with tightly controlled particle size distributions, combined with optimised dispersions, play a crucial role in stabilising droplet formation and enabling consistent, high-quality output.
UV LED AND THE EVOLUTION OF CURING UV curing remains fundamental to digital label printing, supporting instant drying, high line speeds
and excellent print resistance. Increasingly, mercury- based UV lamps are being replaced by UV LED systems. UV LED off ers lower energy consumption, reduced heat output, longer lifespans and environmental advantages such as the elimination of mercury and ozone generation.
This shift, however, requires inks to be reformulated to match the narrower emission spectra of UV LED lamps. Modern UV LED inks are now required to be low migration, low odour and enable compliance to packaging market requirements. Such inks are designed to deliver eff ective curing while preserving colour strength and mechanical performance, even on heat-sensitive label stocks, all whilst minimising any migration and compliance risk.
MIGRATION, COMPLIANCE AND SUSTAINABILITY
For labels used in food, pharmaceutical, cosmetic and personal care markets, migration control is a non-negotiable requirement. Digital inks must be engineered to meet regulations such as the Swiss Ordinance and brand-owner compliance standards, while still delivering the performance required for industrial production.
Alongside UV technologies, water-based inkjet systems are gaining interest for label applications where sustainability and regulatory considerations are particularly important. Advances in resin chemistry, pigment dispersion and drying systems are making aqueous inks an increasingly viable option in the digital label landscape.
LOOKING AHEAD
As digital presses become faster and more precise, ink formulation continues to evolve in parallel. By balancing viscosity, reactivity, stability and compliance, modern digital inks are enabling label converters to achieve new levels of productivity, quality and fl exibility. With the ongoing adoption of UV LED curing and the emergence of advanced water-based solutions, digital label printing is set to play an even greater role in the future of packaging.
www.convertermag.com
May/June 2026
29
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58
