Dell 2145cn Service Manual page 95

4.1.4.4 Periodic Defective Image
If an image defects appears at regular intervals on the printed-paper, it is due to a faulty or damaged roller.
Refer to the table below and check the condition of the appropriate roller.
No Roller
1 OPC Drum
2 Charge Roller
3 Supply Roller
4 Developing Roller
5 Transfer Roller
6 Gap-ring
7 Fusing Belt
Alignment and Troubleshooting
Period
75.4mm
26.7mm
40.8~41mm Periodic Band (by little difference of density)
30.6mm (YMC)
32.5mm(K)
43.9mm Periodic Band (by little difference of density)
39.0mm
127.0mm
4-31
Phenomenon
White and Black Spots
White/Black Spot and Periodic Band
White Spot, Horizontal black band
Periodic Band
White/Black Spot