Printer Monocolor: Uneven Density In Fd - Konica Minolta bizhub C350 Service Manual

Image quality problem
4.3.15

Printer Monocolor: uneven density in FD

A. Typical Faulty Images
B. Troubleshooting Procedure
Step Section
Image check
1
High image
density original
2
LPH Assy
3
Imaging Unit
4
5
LPH Assy
6
Image check
7
Image Transfer
8
Belt Unit
9
4-70
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Check Item
Uneven density of void area occurs. YES Check LPH Unit connector for
Uneven density in FD occurs at a
pitch of 40 mm to 50 mm when a
multi-copy cycle is run using an
original with high image density
(50% or more).
LED retracting lever is locked in
position.
The surface of the PC Drum is
scratched.
Dirty on the outside.
LED surface is dirty.
Monocolor uneven image (uneven
high density) occurs.
Cam gear operates properly.
The problem has been eliminated
through the checks of steps up to 8.
bizhub C350 Field Service Ver2.0 Sep. 2004
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Result
proper connection.
Check the LED Drive Board con-
nectors for proper connection.
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.
NO Slide out the IU and reinstall.
YES Change Imaging Unit.
YES Clean.
YES Clean using the LED Cleaning
Jig.
YES Select "Tech. Rep. Mode" →
"Machine Adjust" → "LPH Rank"
and run "LPH Rank."
NO Change Image Transfer Belt
Unit.
NO Change IU.
→ Change Image Transfer Belt
Unit.
→ Change LPH Assy.
→ Change PIC Board.
→ Change LED Drive Board
→ Change LPH Unit.
→ Change High Voltage Unit
(Image Transfer, Neutralizing).
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Action