For decades, UV inkjet has been built around a relatively simple promise: print fast, cure instantly and deliver durable, high-quality results across an increasingly diverse range of applications.
Matthew Whiting, Global Account Manager for Fujifilm Ink, discusses how in order to succeed, some remarkably sophisticated chemistry is paramount.
One of the most established components of UV curable inkjet formulations is TPO, a photo initiator that has played an important role in the development of digital UV printing since the technology’s early days. Its popularity is understandable. TPO has strong absorption in the near UV region, making it highly effective under the UV LED and mercury lamp systems commonly used in digital printing. It has also offered formulators a valuable balance of curing speed, depth of cure and compatibility with a broad range of monomers and oligomers.
In short, TPO works.
That is precisely why the regulatory developments surrounding it are generating so much discussion across the inkjet industry.
The question facing manufacturers, OEMs and printers is no longer simply whether TPO is effective. It is how the industry can continue delivering the performance that UV inkjet has come to depend on while adapting to an increasingly demanding regulatory environment.
A regulatory conversation that is already underway.
TPO’s regulatory status in Europe has changed significantly. In 2025, TPO was classified under the EU Classification, as a reproductive toxicant Category 1B, alongside its skin sensitisation classification. Its regulatory status has consequently become an increasingly important consideration for those formulating, supplying and using UV curable products.
ECHA also announced recommendation for TPO to be included in the REACH Authorisation List. This is an important step in the regulatory process, although it should not be confused with an immediate ban. The eventual requirements and timing are understood to take approximately 2-3 years from the announcement, with a further ‘sunset date’ expected before a full ban within the EU.
What is clear, however, is that the direction of travel is changing. For an industry that has relied so heavily on a familiar and well understood photo initiator, that deserves attention now, not when a final deadline arrives. Replacing TPO is not simply a matter of removing one raw material and adding another and Fujifilm Ink have already made significant progress.
The chemistry behind the chemistry
UV inkjet formulations are carefully balanced systems. Change one component and the effects can extend well beyond the component itself.
TPO has historically been valued because it contributes to rapid and effective curing, including the ability to achieve the depth of cure required for demanding applications. It is also compatible with a wide variety of formulation components and has benefited from an established global supply chain.
Finding an alternative therefore requires much more than identifying another photo initiator that absorbs UV light. The alternative must work within a complete formulation. It needs to deliver the required cure response while maintaining jetting reliability, adhesion, durability, colour performance, storage stability and compatibility with the intended substrate and print system.
And then there is the production environment. An ink that performs well in a laboratory test is not necessarily an ink that will perform reliably at high speed, through a printhead, across thousands of square metres and under real production conditions.
That is where the real challenge lies. The industry isn’t simply looking for a replacement for TPO. It is looking for a replacement that doesn’t create a new set of problems elsewhere in the system.
Will moving away from TPO increase costs?
TPO has been used extensively for many years and benefits from established manufacturing volumes and supply chains. Its widespread use has also made it a relatively economical component of UV ink formulations.
Alternative photo initiators may initially carry a higher cost, particularly while volumes are lower and manufacturers are adapting their formulations and supply chains.
Over time, as demand for alternative photo initiator technologies increases, economies of scale should improve availability and cost overall in the market.
For larger ink manufacturers, like Fujifilm Ink, scale is an advantage here. The ability to forecast demand, secure raw materials and establish robust supply arrangements can help reduce some of the disruption associated with industry wide formulation change.
But the biggest advantage is not only purchasing power, it’s also the ability to develop alternatives before they are urgently required. Does an ink manufacturer have the ability to be proactive rather than reactive?
Could you argue compliance is becoming part of performance?
For many years, discussions about ink performance have understandably focused on print quality, productivity, adhesion, durability and cost. Those things remain critical, but the definition of performance is evolving.
Today, customers increasingly want to understand the broader profile of an ink: its emissions, VOC characteristics, safety profile, regulatory status and suitability for increasingly demanding applications and environments.
This means compliance can no longer be treated simply as the final checkpoint before a product goes to market, it has to be considered much earlier.
An ink that meets the customer’s print requirements but creates difficulties from a regulatory or environmental perspective is not necessarily a high-performance ink.
The definition of performance is becoming broader: does it print well, does it cure reliably, does it adhere to the substrate, and does it meet the required durability?
But also: Is it compliant, is it suitable for the intended environment, can it support the certifications and market requirements that customers increasingly demand?
This is why standards and certifications such as GREENGUARD Gold and AgBB are becoming increasingly relevant in certain applications. Safety and emissions characteristics can be just as important to an end user as image quality and price.
What is the advantage of Fujifilm Ink developing UV ink inhouse
This is where the structure and capabilities of an ink manufacturer become particularly important.
There is a significant difference between being able to purchase alternative raw materials and having the internal expertise to understand how those materials can be engineered into a high performing ink.
Within Fujifilm Ink’s inhouse development, brings the chemists who understand the formulation together with the analytical specialists who can characterise it, the technical team who can test it in real printing environments, the manufacturing team who understands how to scale it and the regulatory specialists who understand the implications of the chemistry.
When those disciplines operate closely together, the development process becomes considerably more agile:
- A regulatory change identified by the compliance team can feed directly into an R&D programme.
- A formulation challenge identified during print testing can be investigated by the chemists.
- An issue discovered during scale-up can be fed back into formulation.
- And customer requirements can influence development priorities before a technology reaches the market.
That creates a continuous feedback loop between regulation, chemistry, analytical, testing, manufacturing and the customer.
It is an increasingly important capability as the industry moves towards a more complex regulatory landscape, and Fujifilm Ink already leads in this space.
Regulatory expertise should not sit at the end of the process
Perhaps one of the biggest changes taking place in ink development is the role of regulatory specialists themselves.
Traditionally, regulatory activity could be viewed as something that happened once a product had been formulated: prepare the SDS, check classifications, produce the appropriate labelling and make sure the documentation was in place. That model is becoming increasingly difficult to sustain.
If a raw material is likely to face regulatory restrictions several years from now, waiting until the restriction becomes imminent leaves very little time to reformulate, qualify and commercialise an alternative.
Regulatory intelligence therefore needs to feed into product development much earlier.
At Fujifilm Ink, a dedicated regulatory team based in the UK monitors developments in chemical and environmental legislation and works closely with R&D and the commercial team. Its responsibilities include SDS and label amendments, chemical classification investigations, customer and supplier questionnaires, and advising on issues such as raw material exemptions and export limitations.
Crucially, these findings are shared with R&D through regular reviews.
Fujifilm Ink’s philosophy is not to simply react to regulation, it is to anticipate where chemistry needs to go next.
What does this mean for OEMs?
For OEMs, the implications extend beyond choosing an ink supplier. The ink is an integral part of the printing system and makes up the finished product.
Printhead, waveform, ink, curing system, substrate and application all need to work together. A change to the ink can therefore have implications for machine performance, qualification and ultimately the end user’s experience. This makes the relationship between OEM and ink manufacturer increasingly important.
An OEM needs confidence that its ink partner understands not only today’s formulation requirements but also the regulatory landscape that could influence the platform several years from now. That is particularly important for new machine development, where the lifecycle of a platform can extend far beyond the development programme itself.
The right question is therefore not simply: “does this ink work today’’ but instead, “can this ink platform support where our technology needs to go tomorrow?” Innovation rather than reaction.
Is there a danger that regulatory change becomes framed purely as a cost or compliance issue?
It doesn’t have to.
Some of the most significant developments in the ink industry have come from exactly these kinds of challenges: when established approaches are questioned, formulators are forced to explore new chemistry and updated technologies emerge as a result.
The transition away from familiar photo initiator systems could ultimately accelerate innovation in UV inkjet. It could lead to new approaches to curing, improved formulation efficiency, alternative photo initiator architectures and potentially inks that deliver broader performance benefits than simply meeting a regulatory requirement.
The industry should therefore avoid viewing TPO solely through the lens of “what are we going to replace it with? The more interesting question is: “what can we develop next?”
Is TPO just one example of a much broader challenge facing the inkjet industry?
Regulatory requirements are becoming more complex. Customers are asking more sophisticated questions about the products they buy. Supply chains are under increasing scrutiny. And OEMs need confidence that the technologies they integrate today will remain viable as regulations evolve.
In that environment, ink development cannot happen in isolation. It requires chemistry, analytical science, manufacturing, technical expertise and regulatory knowledge working together.
For ink manufacturers like Fujifilm Ink, that integrated capability is already established and provides a genuine competitive advantage for OEM partners. This way of working offers something equally important to OEM partners and that is, confidence.
Confidence that the ink has been engineered for the application, that its performance has been properly understood and that the team behind it is already thinking about the next regulatory and technological challenge.
Will the future of UV inkjet simply be defined by which photo initiator replaces TPO?
No, and that would be a very short-term approach. The team at Fujifilm Ink believes it will be defined by how intelligently the industry responds to the challenge. Regulation may be forcing the question, but chemistry will provide the answers, and innovation will determine what comes next.