Low Density (Under Low Humidity Environment) - Konica Minolta bizhub PRO C6501 Troubleshooting Manual

1 Low density (under low humidity environment)

[Symptom]
The density is low at solid and highlighted part.
[Probable cause]
Increase of toner charge in developer under low humidity environment.
Decrease of developing ability due to the toner charge increase in developer due to the too
high or too low coverage original.
[Solution]
<Solid part>
Access Service mode=> [02 Process Adjustment] => [04 Process Fine Adjustment] => [02
Develop AC Bias Fine Adj.], then increase the adjustment value for the color which you want to
increase the density.
NOTE:
When the density is increased by the [02 Develop AC Bias Fine Adjustment], carrier
attachment occurrence frequency increases. Therefore, please check no white spot which is
resulted from carrier attachment appears on the solid part.
If [02 Develop AC Bias Fine Adj.] cannot solve the problem, also use [03 Develop AC
Frequency].
NOTE:
When the setting value (frequency) is decreased density increases but the image background
tends to occur. Therefore, please adjust carefully.
After the above adjustment, perform Automatic gamma adjustment from service mode or utility
menu
► Service mode => [02 Process adjustment] => [02 Drum peculiarity adjustment] => [03
Auto Gamma adjustment]
► Utility menu => [03 Machine Admin. Setting] => [01 System setting] => [05 Expert
adjustment] => [08 Execute adjust operation] => [Automatic gamma adj.]
<Highlighted part>
After adjusting the solid part, if the highlight is lighter, perform printer gamma offset adjustment
or Printer gamma offset automatic adjustment.
► Service mode => [01 Machine Adjustment] => [03 Quality Adjustment] => [02 Printer
gamma adjustment] => [01 Printer Gamma Offset adj.] or [02 Printer Gamma Offset Auto
adj.]
► Utility menu => [03 Machine admin. Setting] => [01 System setting] => [05 Expert
adjustment] => [07 Quality adjustment] => [01 Printer gamma offset adj.] or [02 Printer
gamma offset auto adj.]
NOTE: Perform Automatic gamma adjustment immediately before performing this adjustment.
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