How to Tell a Bad Plate on Flex Printing

In flexographic printing, the quality of your flexo printing machine is only as good as the plate it uses. Many print defects that appear during production—blurred images, registration errors, or ink smudging—can often be traced back to one root cause: a bad printing plate.

But how do you identify whether your plate is the real issue? More importantly, how do you prevent costly downtime and material waste caused by such errors? This guide walks you through how to tell a bad plate on flex printing, and how to optimize your equipment and workflow to get the most out of every print run.

Why Plate Quality Matters in Flexo Printing

Flexographic printing relies on flexible plates to transfer ink onto corrugated boxes, paper, plastic film, and more. Even the most advanced corrugated flexo printer or folder gluer machine cannot compensate for flaws in the plate itself. A defective plate can ruin an entire production batch, increase operational costs, and damage your brand image.

At Keshenglong, we work closely with packaging manufacturers and converters worldwide to ensure both machine performance and plate compatibility are optimized. Below, we’ll help you identify common plate-related problems and how to resolve them.

5 Signs You’re Using a Bad Plate on a Flexo Printing Machine

1. Skip Printing (Missing Dots or Images)

Symptom: Random blanks or faded images in the print.
Cause: Uneven pressure, plate swelling, or surface contamination.
Solution: Inspect plate surface for dried ink or uneven exposure. Ensure anilox roller and doctor blades are also clean.

2. Dot Gain or Image Distortion

Symptom: Enlarged dots or fuzzy lines that make text or images appear heavier.
Cause: Overexposure during plate making, or incorrect mounting.
Solution: Regularly check plate exposure times and mounting alignment. Use a high-precision inline flexo printing machine to minimize distortion.

3. Misregistration Between Colors

Symptom: Color layers don’t align, causing a shadow effect or color overlap.
Cause: Plate shifting or inconsistent mounting.
Solution: Ensure uniform plate thickness and proper tension control. Keshenglong machines offer auto-registration control to help eliminate such issues.

4. Image Blurring or Smearing

Symptom: Print appears smudged or soft-edged.
Cause: Soft or damaged plate, or excessive impression pressure.
Solution: Replace damaged plates immediately. Calibrate impression settings regularly.

5. Ink Build-up and Dirty Prints

Symptom: Unexpected spots, ink blobs, or ghosting.
Cause: Poor plate cleaning or excessive ink viscosity.
Solution: Use proper cleaning agents. Avoid excessive solvent exposure, which can degrade photopolymer plates over time.

How to Prevent Plate-Related Defects

✅ Visual Inspection Before Setup
Check for nicks, scratches, or embossing issues. Store plates in a clean, climate-controlled environment.

✅ Use High-Quality Plate Material
Low-cost photopolymer plates can degrade quickly. Invest in durable materials suitable for high-speed printing machines.

✅ Match Plate to Machine Capabilities
Not all plates are suitable for every machine. If you’re using a flexo folder gluer or a corrugated box printing machine, ensure the plate matches the line speed, ink system, and substrate used.

✅ Regular Maintenance of Printing Equipment
Even the best plates can fail on a poorly maintained machine. Regular maintenance, calibration, and timely part replacement are essential to ensure optimal performance and consistent print quality.

Why Choose Keshenglong for Flexo Printing?

Keshenglong is a leading manufacturer of automated corrugated packaging machinery, including:

• Full-servo flexo printing machines

• High-speed die cutting machines

• Automatic folder gluers

• Inline printing and slotting solutions

What sets us apart?

🌟 Precision Engineering – Our machines ensure ultra-precise registration and pressure control.
🌟 Custom Integration – Whether you run short box runs or 24/7 high-volume jobs, we tailor solutions to your exact production needs.
🌟 Global Service & Support – With installations in over 80 countries, our support network ensures fast response and minimal downtime.
🌟 Innovation in Automation – Keshenglong pushes the frontier of smart packaging production.

By investing in both high-quality plates and a reliable flexo printing machine, you can eliminate guesswork and produce consistently sharp, vibrant packaging.

💬 Want to learn more about how Keshenglong can help optimize your flexo printing line?
Contact us to explore more or to request a quote.