Applicable Systems
Roland Offset Printing Machine
Symptoms
The print registration is off by more than 0.5mm between colors. The finished product shows misaligned color separations and blurred images.
Possible Causes
- Web tension inconsistent due to worn tension controller or brake
- Printing cylinder bearing play causing position variation
- Registration sensor dirty or misaligned, providing incorrect feedback
- Plate cylinder gear wear causing non-uniform rotation
Troubleshooting Steps
- Step 1: Check the web tension stability using a tension monitoring device
Tension should be within 5% of the setpoint; inspect the tension controller and brake - Step 2: Inspect the printing cylinder bearings for play by pushing and pulling the cylinder
Replace bearings if play is detectable - Step 3: Clean the registration sensor with a lint-free cloth and verify alignment
Adjust the sensor position to match the registration mark on the web - Step 4: Check the plate cylinder gears for wear using a gear tooth gauge
Replace gears if the tooth profile is visibly worn
How to Reset
Reset: After correction, run a test print at production speed and verify registration is within 0.1mm.
Common Replacement Parts
- Registration sensor: Optical, photoelectric type (Match to registration mark color)
- Cylinder bearing: Precision ball bearing, match to cylinder (Replace in matched pairs)
- Tension controller: Dancer or load cell type (Calibrate per OEM specification)
Frequently Asked Questions
- Q: What is print registration?
The alignment of color separations in multi-color printing. For high-quality printing, registration must be within 0.1mm.
- Q: What causes registration errors?
Web tension variation, cylinder bearing play, sensor misalignment, and gear wear. Check the tension system first, as it affects all colors.
- Q: How do I check web tension?
Use a tension meter (hand-held) or read the dancer position on the control panel. Tension should be consistent across the web width.
Source: OEM Operation Manual
Category: Printing