NEC Super Script 4400 Maintenance Manual page 240

18. Toner Streak - Brush mark line of uneven optical density is caused in the image.
Main Causes
1. Main blade of the developer unit and the reset roller is not normal
2. Location of the toner module is not correct.
3. Transport paddle in the toner module is deformed.
4. Brush mark line appears in the continuous printing of high coverage (solid) pattern.
Countermeasures
1. Reseat the toner module.
2. Remove the toner module and rock it left to right.
3. Replace the toner module. (See Chapter 6)
Drum Cleaner
OPC Belt Cartridge
Toner Module
K(Black)
Y(Yellow)
K
M(Magenta)
C(Cyan)
Y
M
C
Imaging Artifacts 231