Lexmark 4500-00 Series, Service Manual

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Diagnostic information
2-89
4500
Partial blank image/white spots (no periodic pattern)
Variation in image density horizontally across page
FRU Action
Toner cartridge (not a FRU) Remove the toner cartridge and
gently shake the assembly to evenly
distribute the toner.
If toner cartridge is low, try a new
one.
Fuser backup roll bearings
(and springs) Check left and right backup roller
springs and backup roller to ensure
adequate even pressure is applied to
the fuser hot roll.
Paper (not a FRU) Make sure recommended paper is
being used.
FRU Action
Toner cartridge (not a FRU) The charge roll may have an
unbalanced pressure against the
photoconductor (PC) drum.
Open the cover about two inches
and observe the charge roll against
the PC. It should be free from binds
and resting against the PC.
Try a new toner cartridge.
Transfer bearing
Transfer roll Check the springs in the left and
right transfer roll bearings. The
bearing assemblies should support
the transfer roll, applying even
pressure to the PC drum.
Replace either or both transfer roll
bearing assemblies if the springs
show signs of damage or fatigue.
Inspect the transfer roll for signs of
wear, damage or contamination.
Replace as necessary.