Technical Bulletin PAGE: 1/1
Model: Model CH-C1 (Office/Pro)
Subject: Troubleshooting for Random Pitch Banding Caused
by Lubricant Falling from the Drum Cleaning Unit
Prepared by: Ryuuta Chino
From: 1st Tech Service Sect. PP Tech Service Dept.
Mechanical
Paper path
Product Safety
Electrical
Transmit/receive
Other ( )
Service manual revision
Retrofit information
Tier 2
Symptom
Banding appears on the printouts at random intervals (random pitch).
Cause
The lubricant in the drum cleaning unit falls into the registration unit and creates smudges
on the ITB encoder sensor. As a result, the engine speed cannot be controlled correctly.
Solution
Clean the ITB encoder with a blower brush.