Likely Causes

1. Dirty or damaged encoder strip: Mis-reads cause carriage jitter.

2. Bi-directional misalignment: Scan seam visible as thin lines.

3. Carriage wheel/rail debris: Mechanical stutter marks.

4. Encoder sensor gap off: Weak/erratic read.

Quick Checks

• Clean encoder with approved solvent.
• Run bi-di alignment at job settings.
• Inspect wheels/rails; remove debris.
• Verify sensor gap/angle per service spec.
• Print vertical line test at low & high speed.
• Re-test after a 15-minute warmup to stabilize conditions.

Step-by-Step Fix

1. Replace damaged strip if scratched — Restores clean timing marks.

2. Set bi-di value from test chart — Eliminates seam lines.

3. Lubricate/clean rails where appropriate — Smooth carriage travel.

4. Adjust sensor bracket — Stabilizes read at speed.

5. Lock to uni-directional for critical jobs — Removes bi-di artifacts.

6. Reset to vendor recommended preset — Establishes a known-good baseline to compare against.