Black Dots Appears On The Image (Image Rendering Problem) - Kyocera TASKalfa 1800 Service Manual

(10) Black dots appear on the image.
Print example
Defective part
Drum unit
1
Charging roller
2
Developer unit
3
Transfer roller unit. Check if the transfer roller is con-
4
Fuser unit
5
1. Dirty charging roller
2. Flawed or dirty drum unit
3. Damaged or paper dust bitten cleaning blade
Check description
Check the print image on paper
has a problem at an interval
equivalent to the circumference
of the drum (126mm).
Check the print image on paper
has a problem at an interval
equivalent to the circumference
of the charging roller (38mm).
1. Check if that the developing
bias is leaked.
2. Check the print image on
paper has a problem at an
interval equivalent to the
circumference of the
developing roller (39mm).
taminated on its surface or dam-
aged.
Check the cleaning bias connec-
tor or the connecting terminals of
high voltage are not dirty or
deformed.
Check the print image on paper
has a problem at an interval
equivalent to the circumference
of the fuser roller.
Cause of trouble
If the drum has scratches, replace the drum
unit. (see page 1-5-40)
A problem is observed at a constant interval of
the charging roller (38 mm), replace the
charging roller. (see page 1-5-40)
Execute AC calibration by U140.
(see page 1-3-51)
1. If the print image on paper has a problem
at an interval equivalent to the
circumference of the developer roller, clean
the developer unit.
2. Replace the developer unit.
(see page 1-5-35)
Replace the transfer roller unit.
1. If the connector or terminals are dirty,
clean.If the connecting terminals are
deformed, correct for a proper conduction.
2. Replace the high-voltage circuit PWB.
1. If the print image has a problem, clean the
fuser roller.
2. If cleaning does not help improve the
symptom, replace the fuser unit.
1-4-79
2NC/2NF/2NG/2NN/3P7/3P8/3P9
Corrective Action