Lexmark W850n Service Manual page 173

The toner adhering to the Magnet Roll is always in contact with the drum surface. When a less negative point on
the drum (a discharged area) comes in contact with the more negative charged toner on the Magnet Roll, toner
transfers from the Magnet Roll to that point on the drum. There is now a visible toner image on the drum surface.
The image is called a developed image.
DRUM
Magnetic
Metering
Roll
Blade
Toner
Drum Surface
Image
Visible Developed Image
HVPS
-VDC
Drum Surface
Voltage
Toner at
-VDC Developer
Bias value
0V
Diagnostic aids
4024-110
Discharge
Level
3-49