Broken Lines or Disconnected Text in Inkjet Printing: Causes and Fixes | Cheef Inkjet

Broken Lines or Disconnected Text in Inkjet Printing: Causes and How to Fix It

In industrial inkjet coding, broken lines or incomplete strokes in characters can lead to unreadable codes, failed scans, and a poor-quality impression. This issue affects all major printer types—CIJ, TIJ, and DOD—and is typically caused by mechanical, ink flow, or software irregularities. Here’s how to identify the cause and take effective corrective action.

Typical Symptoms

• ⚠️ Characters appear fragmented or with gaps in vertical/horizontal lines
• ⚠️ Barcodes are unreadable due to line breaks
• ⚠️ Print quality fluctuates within a single message
• ⚠️ Issue worsens with speed or after long idle periods

Main Causes and Solutions

1. Nozzle Blockage or Partial Clogging

• Cause: Dried ink or dust partially obstructs ink ejection
• Fix:
  • Run a purge or cleaning cycle from the printer control panel
  • Manually clean nozzle with a lint-free cloth and solvent (TIJ/CIJ)
  • Use ultrasonic cleaner for stubborn DOD nozzle blocks

2. Ink Flow Interruption or Air Entrapment

• Cause: Ink line has trapped air bubbles or pressure fluctuation
• Fix:
  • Flush ink system and bleed trapped air from pump lines
  • Replace worn-out filters and check tank levels
  • Stabilize solvent-to-ink ratio in CIJ systems

3. Printhead Alignment Error

• Cause: Printhead is tilted or off-center relative to product surface
• Fix:
  • Re-align printhead and confirm consistent distance from the surface
  • Mount using alignment brackets and confirm level position

4. Resolution or DPI Too Low

• Cause: At low DPI, line detail is lost—especially at fast speeds
• Fix:
  • Increase print resolution or switch to high-contrast font mode
  • Slow down conveyor speed if DPI cannot be increased

5. Substrate Surface Roughness or Coating

• Cause: Uneven or coated surface may reject or distort ink droplets
• Fix:
  • Use fast-drying, surface-adherent ink suitable for the material
  • Apply corona/plasma treatment for high-gloss or film packaging

Operational Tips

• ✅ Perform nozzle tests at the beginning of each shift
• ✅ Maintain clean, temperature-controlled ink storage
• ✅ Use print preview and test mode to validate line consistency
• ✅ Replace old or expired ink, even if partially full

FAQs

• Can DOD printers show broken lines more than others? Yes—due to multiple nozzles firing in coordination, any nozzle deviation causes visible gaps
• Will software updates fix these issues? Not directly—hardware cleaning and ink stabilization are usually required

Conclusion

Broken or disconnected lines in inkjet printing are often caused by partial clogs, air bubbles, or mechanical misalignment. Addressing these issues with cleaning routines, hardware checks, and proper ink handling ensures reliable and high-quality coding. For technical support, printhead accessories, or ink advice, contact Cheef Inkjet at sales@cheef.cn.