5-14 Phaser 6121MFP Service Manual
Print-Quality Troubleshooting
White or Colored Lines and Bands in Feed Direction
Vertical lines or bands in the output indicate problems in the feed direction.
Initial Actions
Perform the initial actions listed on page 5-5.
Troubleshooting Reference Table
Applicable Parts Example Print
■ Scanner Unit, 
PL2.0.4
■ Imaging Unit, 
PL4.0.13
■ Fuser, PL11.0.18
■ Transfer Roller, 
PL7.1.10
■ Laser Unit, 
PL4.0.2
Troubleshooting Procedure Table
Step Actions and Questions Yes No
1 Print Test Pattern 3 (see 
page 6-32).
Does the defect occur on 
the printed output?
The problem is in the 
print image system. 
Go to step 4.
The problem is in the 
Scanner system. Go 
to step 2.
2 This defect often occurs 
when foreign material 
(paper dust, toner, or 
other material) deposits 
on the document glass. 
The scanhead detects the 
foreign material while 
scanning, and the defect 
appears as streaks or 
spots on the copy output.
Thoroughly clean the 
document glass.
Does the defect still 
occur?
Go to step 3. Complete.
Vertical Blank Lines
Chrysanthemum x morifolium
Vertical Stripes
Chrysanthemum x morifolium