Oki B 4100 Maintenance Manual page 529

4) Developing
Toner is attracted to the electrostatic latent image on the EP (image) drum surface to convert it
into a visible toner image. Developing takes place at the contact between the EP (image) drum
and the developing roller.
1
As the toner supply roller rotates while rubbing on the developing roller, a friction charge
is generated between the developing roller and the toner, allowing the toner to be attracted
to the developing roller. (The developing roller surface is charges positive and the toner,
negative.)
2
The toner attracted to the developing roller is scraped off by the doctor blade, forming a
thin coating of toner on the developing roller surface.
3
Toner is attracted to the exposed part (low-potential part) of the EP (image) drum at the
contact between the EP (image) drum and the developing roller, making the electrostatic
latent image visible.
40055101TH Rev.4
Charge roller
EP drum
-300V
+ + + + + + + + + + +
– – – – – – – – – – –
+ + + + + + + + + + + + + + + + + + + + + + +
-750V -100V
Exposed
part
An illustration of activities at the contact point of the
image drum surface and the developing roller (arrow
marks denote the direction of the electric field).
Doctor blade
Toner supply roller
Developing roller
+ + + + + + + + + + + +
– – – – – – – – – – – –
-750V -750V
Exposed
part
-100V
Developing roller
Toner
Image drum
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