Printer Monocolor: Foggy Background - Konica Minolta bizhub C250P Service Manual

Field Service Ver. 2.0 Mar. 2006
25.3.7

Printer Monocolor: foggy background

A. Typical Faulty Images
B. Troubleshooting Procedure
Step Section
State Confirmation →
Table Number
1 (Service Mode)
State Confirmation →
2
Level History 1
(Service Mode)
3
4 Level History data
check results
5
6
7
8 Imaging Unit
PH Unit
9
TCR Sensor window
10
Image Process
Adjustment → Back-
11
ground Voltage Margin
(Service Mode)
Image Process
Adjustment → X-Rite
12 Calibration (Grada-
tion Adjust)
(Service Mode)
Image Process
Adjustment → D Max
13
Density
(Service Mode)
ABCD
ABCD
ABCD
ABCD
ABCD
4036fs4030c0
Check Item
Check data for Vg and Vb.
Color Vdc: Around 400 V
Vg : Around 500 V
Black Vdc: Around 400 V
Vg : Around 500 V
Check TCR data.
IDC output value is around 4.3 V.
Low TCR and low Vg and Vdc
Low TCR and high Vg and Vdc
TCR falling within specified range
and low Vg and Vdc
TCR falling within specified range
and high Vg and Vdc
Dirty on the outside.
The surface of the PH Window is
dirty.
The color TCR Sensor window is
dirty.
The problem is eliminated after
Background Voltage Margin has
been adjusted.
"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.
25. Image quality problem
Result Action
NO Go to next step.
NO Go to next step.
NO Clean IDC Sensor.
Check Transfer Belt for
damage.
YES Go to step 8.
YES Go to step 11.
YES Go to step 8.
YES Go to step 11.
YES Clean.
YES Clean with cleaning jig.
YES Clean.
NO Go to next step.
YES Go to step 15.
NO Go to next step.
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