Sharp SF-1120 - Manual (Page 40)

Step 3 (Development)
Toner is attached to the latent static-electricity images on the drum
surface to change them to visible images. The two-component mag-
netic brush development system charges toner positively by friction
with carriers, and toner is attached to negative charges on the drum
surface. The potential in the darker document projecting area (low
intensity) is high (much negative charges) and attracts more toner.
The potential in the lighter document projecting portion (high intensity)
is low (less negative charges), and attracts less toner.
At that time, a bias of –200V is applied to the MG roller (magnet
roller), which is provided for preventing toner from being attracted by
the residual voltage (about –80V to –100V) in the lighter portion after
exposure.
Main corona unit Blank lamp
Cleaning blade
Discharge lamp
Seperation pawl
Seperation corona unit
Transfer corona unit
Resist roller
MG roller
Developer unit
CTL
CGL
OPC drum
CTL
CGL
OPC drum
Low intensity in
the area corre-
sponding to the
darker density
portion of the
document
Medium intensity
in the area corre-
sponding to the
medium density
portion of the
document HIgh intensity in
the area corre-
sponding to the
lighter density of
the document
Aluminum
layer
Surface potential
(High)
Aluminum
layer
Surface
potential
(Medium)
Surface
potential
(Low)
Main corona unit Blank lamp
Cleaning blade
Discharge lamp
Seperation pawl
Seperation corona unit
Transfer corona unit
Resist roller
MG roller
Developer unit
CGL
OPC drum
CTL
-200V
Aluminum layer
Higher surface
potential
(Much negative
( charges)
Medium surface
potential
(Less negative
( charges)
Lower surface
potential
(No negative
( charges)
MG roller
High voltage unit
bias voltage
5 – 11