Drum Unit; Photosensitive Drum; Primary Charger; Developer Roller - Brother HL-1070 Service Manual

2.4

Drum Unit

2.4.1
Generates the latent electrostatic image and develops the image on the drum surface.
2.4.2
Forms a uniform charge on the drum surface.
(1)
(2)
2.4.3
Develops the latent electrostatic image on the drum surface by the addition of the toner.
2.4.4
Transfers the toner image to the paper from the drum surface.
2.4.5
Removes and recycles the toner remaining on the drum surface.
2.4.6
Discharges the electrostatic latent image on the drum.
2.5

Print Process

2.5.1
The drum is charged to approx. +1000V by an ion charge which is generated by the
primary charger. The charge is generated by ionization of the corona wire, which has a
DC bias from high-voltage power supply applied to it. The flow of the ion charge is
controlled by the grid to ensure it is distributed evenly on the drum surface. The drum
sleeve is regulated to approx. 280V by the voltage regulator.
Voltage
Regulator
The primary charge uses a corona wire, but since the drum is positively charged, only
less than 1/10 of the usual quantity of ozone is generated compared with the negatively
charged drum. The level of ozone expelled from the printer is therefore not harmful to the
human body. Applicable safety standards have been complied with.
Download Free Service Manual and Resetter Printer at http://printer1.blogspot.com

Photosensitive Drum

Primary Charger

Corona wire
Generates the ion charge on the drum.
Grid
Spreads the ion charge evenly over the drum surface.

Developer Roller

Transfer Roller

Cleaner Roller

Erase Lamp

Charging

-
+ -
-
+
- -
+
- -
+
+ +
1000V
Corona wire
280V
Aluminum drum sleeve
- - - -
Organic Photoconductor layer
+ + +
+
Grid
+
+
+
+
+
+
+
+
+ + +
HVPS
Fig. 2.27
II-21
Passive Type
Voltage Regulator
Drum