NEC Super Script 4400 Maintenance Manual page 228

6. White Line I - Vertical white line appears in a specific color area when test-printed in the four color mode
(Stripe Mode)
Main Causes
1. Foreign particles adhered to Developer Roller of specific color in question.
2. Foreign particles adhered to the Toner Module's Main Blade of specific color in question.
Developer Roller
Toner Drop
Countermeasures
1. Implement the test print.
2. Confirm which toner module has caused the white line.
3. Remove the foreign particles adhering to the developer roller.
Toner Module
OPC Belt Cartridge
K
Y
M
C
Toner Module
K(Black)
Y(Yellow)
M(Magenta)
C(Cyan)
Imaging Artifacts 219