3.3 DIRTY BACKGROUND
- Problem -
1. Dirty background at image density level 4 (manual setting).
2. Copies made in ADS mode have a dirty background.
- Possible Causes -
1. V
correction failure
L
Very dirty optics (V
•
Deteriorated exposure lamp (maximum output cannot give sufficient light
•
intensity)
Failure of the dc power supply board
•
Dirty erase lamp unit
•
2. V
correction failure
R
CB (development bias) high voltage supply board failure
•
Poor development bias terminal contact
•
The development bias is grounded
•
3. The OPC drum is not grounded properly
4. ADS mode
Improper ADS Density setting (SP5-106)
•
ADS Sensor board failure
•
CB high voltage supply board failure
•
Incorrect adjustment of the ADS sensor (SP4-201)
•
Sensitivity of the ADS sensor is not correct for the original
•
5. High toner density
Improper setting of the drum charge voltage adjustment (SP2-001)
•
Improper V
pattern bias (SP2-203)
•
SP
Dirty erase lamp unit
•
6. Drum charge roller thermister error
Connector of the drum charge roller thermistor id not connected properly.
•
Broken drum charge roller thermistor
•
FSM
correction cannot compensate)
L
6-5
FT5535/4527/4522