Applicable Systems
MAN Roland Offset Printing Machine
Symptoms
The printing blanket has a visible tear or lump. The printed image shows a repeating defect at the blanket cylinder circumference.
Possible Causes
- Blanket damaged by a paper web break or foreign object passing through the nip
- Blanket over-tightened during installation causing edge damage
- Blanket glue layer degraded from excessive solvent wash
- Blanket undercut too deep, causing paper embossing and early failure
Troubleshooting Steps
- Step 1: Remove the blanket and inspect the surface for tears, lumps, or chemical damage
Replace the blanket if any visible damage is found - Step 2: Clean the blanket cylinder surface and inspect for damage
Resurface the cylinder if it is scored or corroded - Step 3: Install the new blanket with the correct tension per the manual specification
Use a torque wrench on the blanket tensioning mechanism - Step 4: Verify the blanket undercut is correct using a depth gauge
Adjust the packing to achieve the correct impression pressure
How to Reset
Reset: After blanket replacement, run test prints and verify the defect is eliminated.
Common Replacement Parts
- Printing blanket: Compressible type, 1.95mm thick (Match to press model and application)
- Blanket packing: Calibrated paper, 0.05-0.10mm (For impression adjustment)
- Torque wrench: 0-50 Nm, calibrated (For blanket tensioning)
Frequently Asked Questions
- Q: How often should blankets be replaced?
After 10-30 million impressions, depending on paper quality and washing frequency. Inspect daily for damage.
- Q: How do I wash a blanket?
Use OEM-approved wash and a clean cloth. Wash in the direction of cylinder rotation. Avoid excessive solvent that degrades the blanket glue layer.
- Q: What is blanket undercut?
The depth that the blanket surface sits below the cylinder bearers. Correct undercut ensures proper impression pressure without embossing the paper.
Comments (0)
Share your experience to help others facing the same problem.
Leave a Comment
Source: OEM Operation Manual
Category: Printing
No comments yet. Be the first to share your experience!