Repetitive-defects troubleshooting
Defects on printer rollers can cause image defects to appear at regular intervals on the page. Use
Table 6-26 Causes of repetitive defects on page 225
to determine which roller is causing the defect.
To resolve the problem, try cleaning the roller. If the roller remains dirty after cleaning or if it is damaged, replace it.
Repetitive defects for the transfer unit normally appear on every other page, because the transfer belt is longer than a page. However, the period of the repetitive defect can vary depending on the type of media, and a repetitive defect can occur more than once on the same page.
CAUTION: Do not use solvents or oils to clean rollers. Instead, use lint-free paper to clean the roller. If dirt is difficult to remove, dampen the paper with rubbing alcohol.
NOTE: Defects on the tray 2 pickup roller or the multipurpose-tray pickup roller do not cause a repetitive defect, but instead cause a defect on the leading edge of the page.
Table 6-26 Causes of repetitive defects
Problem Area Period of defect (mm)
Problem
Primary charging roller
Developing cylinder
Registration roller (inside)
Registration roller (outside)
Transfer roller
Fuser sleeve
Photosensitive drum
Fuser pressure roller
About 27
About 27
About 35
About 36
About 44
About 75
About 76
About 79
X
X
X
X
X
X
Dirt on front
X
X
X
X
X
Blank spots
X
X
Dirt on back
X
Poor fuser
X
X
Repetitive print defects are usually caused by a specific roller, cylinder, or drum in the printer or the print cartridge. Use the following figure to isolate the cause of repetitive print defects. Align the first occurrence of the defect with the top of the “ruler” (at the top or bottom of the misprinted page), and measure to the next occurrence of the defect to determine which roller, cylinder, or drum is causing the defect. When the defect pattern matches the pattern of the ruler, replace the indicated part.
ENWW Repetitive-defects troubleshooting 225
First occurrence 0mm
Primary charging roller 27mm
Developing cylinder 27mm
Registration roller (inside) 35mm
Registration roller (outside) 36mm
Transfer roller (inside) 44mm
Fuser sleeve 75mm
Photo sensitive drum 76mm
Fuser pressure roller 79mm
Figure 6-2 Repetitive defect ruler
NOTE: Transfer unit defects usually appear on every other page because the transfer belt is longer than a page. However, the defect distance might vary depending on the type of media that is being used. It is possible to see a repetitive defect more than once on the same page.
226 Chapter 6 Troubleshooting ENWW
