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Deflection vs. Missing Nozzles: How to Tell What's Actually Wrong With Your UV Print
Deflection vs. Missing Nozzles: How to Tell What's Actually Wrong With Your UV Print
CMBACRYLIC UV PRINTING
UV Printing · Test Print Diagnostics
What's wrong with my test print? Diagnosing deflection, missing nozzles & white ink issues
Streaky, incomplete, or off test print? Here's how to tell which of three common causes you're actually looking at — before you start troubleshooting the wrong one.
Missing nozzle
A nozzle isn't firing. Shows up as a clean, blank gap in a solid color band.
Deflection
The nozzle fires, but off-target. Shows up as streaky, uneven color instead of a gap.
White ink settling
Titanium settles in the print head. Shows up only on white, when the top & bottom — three quarters of the channels — go missing.
If you've ever pulled a test print off the bed and it didn't look right — streaky, incomplete, or just off — you've probably had the same first reaction most UV printer owners do: run a nozzle check, see the pattern looks mostly fine, and assume the problem must be somewhere else — the file, the material, the ink.
But here's the catch: a nozzle check can look clean and your print quality can still be off. That's because there are actually three different problems hiding behind "my test print isn't right," and they don't get fixed the same way — two show up in any color, and one is specific to white ink.
Culprits 1 & 2
Missing nozzles vs. deflection
Side by side, on a CMYK test bar: missing nozzles read as precise, blank lines in an otherwise solid color. Deflection reads as rough, textured streaking — the whole band looks a little off rather than interrupted.
Why it matters
Why the distinction matters
Same symptom on the printed piece — banding, lines, streaks — but different root causes mean different fixes.
Missing nozzles
Usually responds to a standard nozzle wash. Clogged or dried ink is blocking that nozzle from firing at all, so clearing it out — starting with your daily maintenance liquid and working up to a stronger one if needed — solves it.
Deflection
A mechanical or ink-flow issue with that specific nozzle — it's firing, just inaccurately. A basic wash may not resolve it, and repeated aggressive cleaning can make it worse. If a wash doesn't correct it, call your tech.
The trap: a "perfect" nozzle check
It's possible to run a nozzle check, see every channel firing, and still get a streaky, inconsistent print. A nozzle can pass a basic check and still be deflecting slightly — enough to show up as banding on an actual job, even though the test pattern looked fine. If your test print looks clean but your production prints don't, inspect the print itself for the difference above before deciding your next step.
Culprit 3
White ink channels acting up
This one only shows up on white, and it looks different from the color-channel issues above: instead of streaking or a single blank line, you'll see the top and bottom — three quarters of the white channels total — go missing on your test print, with only a narrow band still firing.
Titanium is the pigment that gives white UV ink its opacity, and it's heavy — over time it can settle out and collect unevenly in parts of the white print head. That settling is what causes those top and bottom sections to stop firing, even though nothing is actually clogged the way it would be with a missing nozzle.
Symptom
Top and bottom — three quarters of the white channels total — are missing on a test print.
Fix
Run White Maintain to redistribute the settled titanium through the print head. This isn't a nozzle wash issue, so a standard cleaning cycle won't fix it on its own.
At a glance
Quick reference
| What you see | Likely cause | What to do |
|---|---|---|
| Clean, blank line through a color band | Missing nozzle (clogged) | Run a nozzle wash |
| Streaky, uneven, textured color band | Deflection | Try a wash; if it persists, call your tech |
| Nozzle check looks fine, print still looks streaky | Hidden deflection | Don't rely on the test alone — inspect the actual print |
| Top and bottom — three quarters of white channels — missing | Titanium settling in the white head | Run White Maintain |
Knowing which of the three you're looking at before you start troubleshooting saves ink, saves time, and tells you whether this is a clean-it-yourself problem, a White Maintain fix, or a needs-a-service-call problem — which is half the battle when something's wrong with a print.
Keep going
Printer running clean? Time to print.
Once your test print looks right, stock up on the acrylic, wood, and metal blanks you need for the job.
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