Abnormal Image Printing And Defective Roller - Samsung ML-920 Service Manual

Error Status
Different image density
(left and right)
Horizonral band
Digital Printer
Digital Printer
Digital Printer
Digital Printer
Digital Printer

Abnormal Image Printing and Defective Roller

If abnormal image prints periodically, check the parts shown below.
NO Roller
1 OPC Drum
2 Charge Roller
3 Supply Roller
4 Develope Roller
5 Transfer Roller
6 Heat Roller
7 Pressure Roller
Samsung Electronics
Check
1. Charge roller's pressure force unbalance
2. Dev. roller and OPC or Dev. roller and
blade's pressure force unbalance
3. Transfer roller's pressure force unbalance of
each side
1. Unstable high voltage contact
2. Charge roller's contamination
3. Contamination of heat roller
4. Malfunction of LSU
Abnormal image period
94.3 mm
37.7 mm
35.8 mm
44.8 mm
57.8 mm
82.5 mm
69.1 mm
Solution
1~2. Change toner cartridge
3. Check left and right spring of transfer roller
and the spring pressing the developer
inside the machine
1. Clean each contact and check good contact
2. Clean charge roller
3. Replace fuser unit
4. Check Main PBA.
Kind of abnormal image
White spot. Black spot
White spot. Black spot
Horizontal dark band
Horizontal dark band
Black side contamination/transfer fault
Black spot, White spot
Black side contamination
Troubleshooting
4-17