Printer 4-Color: Low Image Density - Konica Minolta bizhub C450 Service Manual

18. Image quality problem
18.3.31

Printer 4-Color: low image density

A. Typical Faulty Images
B. Troubleshooting Procedure
Step Section
Paper
1
Image Transfer
2
Belt Unit
Image Transfer
3
Roller Unit
4
5 IDC Sensor
Image Process
Adjustment
→Gradation
6
Adjust
(Service Mode)
Image Process
Adjustment
7
→ D Max Density
(Service Mode)
Image Process
Adjustment
→ Stabilizer →
8
Reset + Stabi-
lizer
(Service Mode)
9
412
ABCDE
ABCDE
ABCDE
ABCDE
ABCDE
Check Item
Paper is damp.
Terminal is dirty.
Image Transfer Roller is installed
properly.
Image Transfer Roller is dirty or
scratched.
Sensor is dirty.
"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 Den-
sity.
After the Reset + Stabilizer
sequence has been completed, run
Gradation Adjust; if the problem
persists, make adjustments of D
Max Density.
The problem has been eliminated
through the checks of steps up to 8.
Field Service Ver. 1.0 Mar. 2005
4036fs4036c0
Result
YES Change paper to one just
unwrapped from its package.
Install Paper Dehumidifying
Heater.
YES Clean.
NO Reinstall.
NO Change Image Transfer Roller
Unit.
YES Clean with blower brush.
YES Go to step 10.
NO Go to next step.
NO Go to next step.
NO Change Image Transfer Roller
Unit.
→ Change Image Transfer Belt
Unit.
→ Change MFP Control Board
→ Change High Voltage Unit/2
(Developing Bias).
→ Change High Voltage Unit/1
(Image Transfer, Neutralizing).
Action