Broken Characters or Missing Strokes in Inkjet Printing: Causes and How to Fix Them

When characters printed by an inkjet printer appear incomplete—with broken lines, missing dots, or partial strokes—it can impact traceability and product quality. This problem is especially common in CIJ, TIJ, and DOD printers when the nozzle, ink system, or settings malfunction. This article provides a clear breakdown of common causes and how to restore full, crisp characters.

Key Symptoms

• ⚠️ Letters or numbers look broken or partially erased
• ⚠️ Barcodes are unreadable due to line gaps
• ⚠️ Text is legible but visually defective or unprofessional

Common Causes and Solutions

1. Nozzle Blockage or Partial Clogging

• Cause: Ink dries at nozzle exit or particles partially block flow
• Fix:
  • Clean the nozzle with approved solvent
  • Run nozzle purge or flush cycle from control panel
  • Replace TIJ cartridge or DOD printhead if clog persists

2. Ink Flow Disruption or Air in System

• Cause: Inconsistent pressure, trapped air, or weak pump performance
• Fix:
  • Check ink levels and flush air from lines
  • Inspect pump pressure readings in diagnostics
  • Replace or service faulty pump or filters

3. Print Resolution or Layout Errors

• Cause: Layout file too low in DPI or character stroke width too thin
• Fix:
  • Increase resolution (TIJ: 300–600 DPI; DOD: 100–300 DPI)
  • Use bold font or adjust stroke thickness in message editor

4. Substrate Surface Interference

• Cause: Uneven or porous material causes ink to break up
• Fix:
  • Switch to compatible ink with better adhesion or penetration
  • Use surface treatment (e.g., corona or primer)

5. Printhead Position or Distance Error

• Cause: Too far from substrate or not perpendicular
• Fix:
  • Re-align head within optimal range (CIJ: 2–6mm, TIJ: 1–2mm)
  • Adjust bracket for a stable perpendicular print angle

Maintenance and Monitoring Tips

• ✅ Run daily nozzle test patterns to detect early stroke loss
• ✅ Keep ink fresh and store cartridges in clean, dry environments
• ✅ Schedule weekly cleaning and monthly calibration

FAQs

• Does a partially blocked nozzle always require replacement? Not always—start with a flush or solvent soak; only replace if blockage is severe
• Is this issue more common with TIJ or CIJ? Both can experience it, but TIJ is more sensitive to cartridge dryness or damage

Conclusion

Missing strokes or broken characters usually result from nozzle blockage, ink delivery issues, or layout weaknesses. Quick diagnosis and proper adjustments will restore full clarity. For technical support, cleaning kits, or layout correction assistance, contact Cheef Inkjet at sales@cheef.cn.