> When Images like These Are Output > When Paper with a Longer Width is Used After Copying or Printing Large Volumes of Paper with a Shorter Width, Dirty Black Bars Appear or Colors are Faint on the Left and Right Edges of Paper > Dirty Black Bars Appear on the Left and Right Edges of Paper
4WK8-02E

Dirty Black Bars Appear on the Left and Right Edges of Paper

Both sides of the pressure belt are dirty. Clean the pressure belt.
← Feeding Direction
Remedy
Clean the pressure belt.
Press  → [Adjustment/Maintenance] → [Maintenance] → [Clean Belt].
 "Maintenance" > "Routine Cleaning" > "Output Paper Becomes Dirty (Belt Cleaning)" in the User's Guide