Ricoh CH-C1 - RTB 77: Banding at 2~3 mm intervals

Technical Bulletin PAGE: 1/2
Model: Charis-C1 office (D135)
Date: 19-Feb-14
No: RD135077
Subject: Troubleshooting Banding at 2~3mm intervals
Prepared by: Ryuuta Chino
From: 1st PP Tech Service Sec., PP Tech Service Dept.,
Classification:
Troubleshooting
Mechanical
Paper path
Product Safety
Part information
Electrical
Transmit/receive
Other ( )
Action required
Service manual revision
Retrofit information
Tier 2
Symptom
Banding (uneven density) at 2~3mm intervals
Cause
Vibration of the cleaning unit synchronizes with the vibration generated by the gears that
rotate the Cleaning Brush Roller, creating a resonance.
This occurs specifically when the Cleaning Brush Roller rotates at the following 2 speeds,
which are defined as “Environment Coefficients 7 & 8” based on the absolute humidity
detected internally by the machine.
Operation mode
Absolute
humidity
Cleaning brush roller rotation
speed coefficient
Environment Coefficient 7
15~17.5 gm3
1.63 (default)
Environment Coefficient 8
17.5~20 gm3
1.76 (default)
Reference
Environment Coefficient 1~3 : Low temperature and low humidity
Environment Coefficient 4~6 : Optimum machine operational condition (laboratory)
Environment Coefficient 7~10 : High temperature and high humidity
2~3mm
Feed
direction