Printer Monocolor: Foggy Background - Konica Minolta bizhub C350 Service Manual

Image quality problem
4.3.19

Printer Monocolor: foggy background

A. Typical Faulty Images
B. Troubleshooting Procedure
Step Section
State Confirm →
Table #
1 (Tech. Rep.
Mode)
State Confirm →
2
Level History 1
(Tech. Rep.
3
Mode)
4 Level History data
check results
5
6
7
LPH Assy
8
9 Imaging Unit
10 LPH Assy
ATDC Sensor
11
window
Image Adjust →
Background Volt-
12
age Margin (Tech.
Rep. Mode)
Gradation Adjust
(Tech. Rep.
13 Mode)
4-76
ABCD
ABCD
ABCD
ABCD
ABCD
4036fs4030c0
Check Item
Check data for Vg and Vb.
Color Vb: Around 390 V
Vg: Around 500 V
Black Vb: Around 390 V
Vg: Around 500 V
Check ATDC data.
AIDC output value is around 4.3 V.
Low ATDC and low Vg and Vb
Low ATDC and high Vg and Vb
ATDC falling within specified range
and low Vg and Vb
ATDC falling within specified range
and high Vg and Vb
LED retracting lever is locked in
position.
Dirty on the outside.
The surface of the lens array is dirty.
The color ATDC Sensor window on
the LED Assy 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
bizhub C350 Field Service Ver2.0 Sep. 2004
Result
NO Go to next step.
NO Go to next step.
NO Clean AIDC Sensor.
Check Transfer Belt for dam-
age.
YES Go to step 8.
YES Go to step 12.
YES Go to step 8.
YES Go to step 12.
NO Slide out the IU and reinstall.
YES Clean.
YES Clean with cleaning jig.
YES Clean.
NO Go to next step.
YES Go to step 17.
Action