Why You Should Not Mix UV Ink With DTF or DTG Ink
Recently, we showed our new fabric printer at IFA Berlin.
Since then, we have been asked a very practical question. If the new machine looks familiar, why not just clean the eufyMake E1, change the ink, add an accessory, and use it for fabric too?
We understand the thinking. If you already own an E1, that sounds like the cheapest path. Keep the machine, swap the ink, and do more with what you already have.
But this is exactly where the real limitation appears. UV ink and fabric ink are not the same kind of system, and they should not be mixed.
By fabric ink here, we mean the inks used for DTF and DTG printing.
What happens when UV ink and fabric ink meet
Before we talk about printheads, cleaning, or chemistry, it helps to start with something much simpler.
Just look at what happens when the two systems meet.
To make this practical, we ran real tests in our lab, so you do not have to. You can see the results in the images below.
From the photo, you can clearly see UV ink and fabric ink do not stay together.
Right after stirring, the mix may look usable for a moment. Leave it there, and separation starts showing up. You may see layering, cloudy boundaries, floating material, trapped droplets, or residue on the cup wall.
You may think stronger stirring will fix that. It usually does the opposite.
Forced stirring can create a temporary emulsion. It may look more uniform for a short time, but the mixture is still unstable.
After that you may get foam, sticky residue, larger droplets, or partially reacted material left on a surface.
A short technical note, if you want the chemistry behind it
If you are mainly here for the practical answer, you can skip this section.
If you want a little more detail, one useful term is Hansen Solubility Parameters.
It is a way to describe how likely liquids are to stay compatible, based on three kinds of molecular interaction: dispersion, polarity, and hydrogen bonding.
Typical UV curable acrylate systems are far from water based fabric ink systems in those values. In the material we tested, typical UV monomers were around:
- δD about 16 to 17
- δP about 5 to 7
- δH about 5 to 9
By contrast, common components in fabric ink systems sit much higher in polarity and hydrogen bonding. For example:
- water: δP 16.0, δH 42.3
- glycerol: δP 12.1, δH 29.3
- ethylene glycol: δP 11.0, δH 26.0
You do not need to remember the numbers. The gap between them is what matters.
There is another difference too. UV ink is designed to cure very quickly under UV light. Fabric ink reaches its final state in a different way, usually through drying, heat, crosslinking, or physical fusion.
Put those systems together, and they disturb each other.
Why this is hard on the printhead
Inside a printhead, the channels and nozzles are extremely small. In industrial inkjet systems, nozzle openings are often around 20 to 40 microns, smaller than the width of a human hair.
At that scale, small changes in liquid behavior become serious problems.
When UV residue and fabric residue meet in those channels, the mix can turn unstable very quickly. Fine particles may start grouping together. Soft residue can collect in bends and slow flow areas, then move later toward the nozzle.
In some cases, the two systems can leave behind gel like material that neither original ink would create on its own.
From the outside, this can look like a normal clog at first. A few nozzles drop out. Cleaning brings some of them back. Then the issue returns.
After that, print quality starts drifting, or curing and adhesion become less consistent than before.
When a printhead becomes unstable, the cost is not only the part itself. It can also mean downtime, wasted ink, repeated cleaning, failed prints, and time spent trying to figure out what changed.
If the same problem keeps coming back, replacement becomes more likely. The total cost rises quickly. It is frustrating, and it makes the printer much more expensive to own.
Why cleaning alone is not enough
This part can feel confusing, because within UV printing, cleaning does work for some switches.
For example, when we switch between rigid and flexible white UV inks, flushing is part of the process. So it is natural to think the same idea should work for fabric ink too.
But those UV inks still belong to the same broad chemistry family. The cleaning step is designed around that family.
A switch from UV ink to fabric ink is different. The liquid behaves differently. The residue behaves differently. The final film forms differently too.
A switch may look fine at first, then lead to cross contamination, extra cleaning, repeated test prints, wasted ink, wasted media, and time spent tracing a problem that did not seem obvious at first.
So a line can look flushed and still cause trouble afterward.
Two examples from small businesses
One small label business tried to test fabric related output on an industrial UV printer without adding a separate setup.
The machine was flushed, the new workflow was introduced, and everything looked acceptable at first. After a short run, nozzle performance started changing. Some channels misfired.
More cleaning helped briefly, but the problem kept coming back. Residual UV related material was still inside parts of the ink path, and once the fabric ink moved through, softened residue and incompatible fragments began interfering with flow near the printhead.
Another small custom print business started seeing uneven adhesion on jobs that normally ran without any trouble.
The media had not changed. The settings had not changed. But the result had.
After a closer workflow review, the likely cause was trace contamination from shared refill or handling tools used across different ink samples. Only a very small amount had entered the UV process, but it was enough to change how the ink wet the surface before curing.
The printer still ran, which made the issue harder to spot. But the output was no longer consistent. That is one reason we decided not to take this approach.
Final takeaway
DTF and DTG ink should not be used in a UV printer.
You can see the incompatibility in the liquid itself. You can see it again after forced mixing. Inside the machine, the risk grows quickly, especially around the printhead.
That is also why switching from a UV system to a fabric system takes more than a cleaning step.
