Konica Minolta magicolor 7450, Service Manual

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Field Service Ver. 1.0 May 2006 16. Image quality problem
217
magicolor 7450
T
roubleshooting
16.3.3 Monocolor: uneven density in sub scan direction
A. Typical Faulty Images
B. Troubleshooting Procedure
4036fs4043c0 4036fs4044c0 4036fs4045c0
Step Section Check Item Result Action
1
High image
density original Uneven density in Sub Scan Direc-
tion occurs at a pitch of 40 mm to
50 mm when a multi-print cycle is
run using an original with high
image density (50% or more). YES Feed 10 to 20 blank sheets of
paper with no originals placed, as
the IU fails to keep up with a high
demand for toner.
2
Imaging Unit The surface of the PC Drum is
scratched. YES Change Imaging Unit.
3 Dirty on the outside. YES Clean.
4
PH Unit The surface of the PH Window is
dirty. YES Clean with cleaning jig.
5 Transfer Belt Cam gear operates properly. NO Change Transfer Belt.
6
The problem has been eliminated
through the checks of steps up to 5. NO Change IU.
→
Change PH Unit.
→
Change Controller Board.
→
Change High Voltage Unit
(Image Transfer, Neutralizing).