Why Your Coating Looks Uneven: Common Anilox Roller Issues

Uneven coating is one of the most common—and most costly—problems in printing and packaging production. Whether you’re applying UV varnish, water-based coatings, primers, or adhesives, the anilox roller plays a decisive role in film uniformity.

When the coating looks streaky, blotchy, patchy, or inconsistent, the root cause often lies inside the anilox cell structure or its condition.

This article explains the most common anilox-related causes of uneven coating and how to identify—and fix—them.

1. Why the Anilox Roller Matters for Coating Uniformity

The anilox roller meters and transfers the exact amount of coating required.
If the roller fails to release a consistent volume, the final coating will look:

• streaky

• too thick in some areas

• too thin in others

• glossy in parts, matte in others

• rough or “orange peeled”

Because coating viscosity and surface tension are highly sensitive, any variation in anilox condition immediately appears on the final product.

2. The Most Common Anilox Roller Issues Causing Uneven Coating

Below are the problems most frequently responsible for non-uniform coating results.

2.1 Plugged or Contaminated Anilox Cells

This is the #1 cause.

Symptoms

• Random streaks

• Matte spots

• Thin or missing coating areas

Causes

• UV varnish residue

• Adhesives cured inside cells

• Improper cleaning

• Delayed cleaning after production

Solution

• Deep clean using laser, chemical, or ultrasonic methods

• Clean immediately after each job

• Implement regular volume inspections

2.2 Worn or Damaged Anilox Surface

Over time, ceramic surfaces can wear, chip, or crack.

Symptoms

• Coating becomes inconsistent even after cleaning

• Higher coating consumption

• Poor gloss performance

Causes

• Excessive doctor blade pressure

• Contact damage during handling

• Long-term erosion of ceramic

Solution

• Reduce blade pressure

• Inspect under microscope

• Replace roller if volume loss exceeds ±10%

2.3 Incorrect BCM or Line Count Selection

Choosing the wrong cell volume or LPI directly affects film thickness.

Symptoms

• Rough or orange-peel surface → volume too high

• Patchy or dull coating → volume too low

Typical mistakes

• Using print LPI instead of coating LPI

• Using too high BCM for thin varnish

• Using too fine engraving for thick coatings

Solution

Match the anilox to the coating type:

2.4 Doctor Blade Issues

The doctor blade meters the anilox roller.
Any imperfection leads to coating variations.

Symptoms

• Lines across the coating

• Uneven metering

• Scratches in the coating layer

Causes

• Worn blades

• Improper blade angle

• Damaged chamber seals

Solution

• Adjust angle (30°–35° recommended)

• Replace worn blades

• Use correct stiffness and coating-compatible materials

2.5 Roller Concentricity or Runout Problems

If the anilox roller does not rotate perfectly:

Symptoms

• Coating heavy on one side, light on the other

• Periodic banding

• Vibrations at high speeds

Causes

• Damaged journal

• Shaft wear

• Manufacturing defects

Solution

• Measure TIR (Total Indicated Runout)

• Repair or replace roller

3. How to Prevent Uneven Coating in Daily Production

✔ Clean immediately after use

Coating materials cure quickly, especially UV varnish.

✔ Implement scheduled deep cleaning

Laser cleaning ensures full-volume restoration.

✔ Measure cell volume regularly

Use instruments like AniCAM to track volume loss.

✔ Choose proper BCM/LPI for each job

Your coating supplier can suggest optimal parameters.

✔ Use high-quality ceramic anilox rollers

Dense ceramic and precise engraving = better coating uniformity.

4. Why JCTPRINT Anilox Rollers Deliver More Uniform Coating

JCTPRINT manufactures high-performance ceramic anilox rollers ideal for coating and varnishing units.

Advantages:

• Swiss Oerlikon Metco ceramic coating

• ALE high-precision laser engraving

• Custom BCM/LPI for coating applications

• Smooth cell walls for superior release

• Long lifespan and consistent transfer

• Solutions for coating machines, laminators, flexo presses, and digital primers

Our rollers are used in 40+ countries by professional printing and packaging manufacturers.

Conclusion

Uneven coating is almost always caused by issues within the anilox roller—plugged cells, worn ceramic, incorrect specifications, or doctor blade problems.
By selecting the right anilox and maintaining it properly, you can achieve:

• smoother finishes

• stable gloss levels

• reduced coating waste

• consistent, high-quality production