Printer Monocolor: Gradation Reproduction Failure - Konica Minolta bizhub C450 Service Manual

Field Service Ver. 1.0 Mar. 2005
18.3.18

Printer Monocolor: gradation reproduction failure

A. Typical Faulty Images
B. Troubleshooting Procedure
Step Section
Photo/Density
1
LPH Assy
2
3 Imaging Unit
4 LPH Assy
TCR Sensor win-
5
dow
State Confirma-
tion → Level His-
6
tory 1
(Service Mode)
Image Process
Adjustment
→Gradation
7
Adjust
(Service Mode)
Image Process
Adjustment →
8
D Max Density
(Service Mode)
Image Process
Adjustment
→ Stabilizer →
9
Reset + Stabi-
lizer
(Service Mode)
4036fs4048c0
Check Item
Original type and screen pattern are
selected properly.
LED retracting lever is locked in
position.
Dirty on the outside.
The surface of the lens array is dirty.
TCR Sensor window is dirty.
IDC output value is around 4.3 V.
"Conv. Value" falls within the speci-
fied range as checked through Gra-
dation Adjust.
Max: 0 ± 100
Highlight = 0 ± 60
The problem has been eliminated
through the adjust of D Max.
After the Reset + Stabilizer
sequence has been completed, run
Gradation Adjust; if the problem per-
sists, make adjustments of D Max
Density.
18. Image quality problem
4036fs4049c0
Result Action
NO Change screen pattern.
YES Slide out the Imaging Unit and
reinstall.
YES Clean.
YES Clean with cleaning jig.
YES Clean.
NO Clean IDC Sensor.
Check Image Transfer Belt for
damage.
YES Go to step 11.
NO Go to next step.
NO Go to next step.
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