Brother HL-3450CN Service Manual page 66

2 Exposing
The exposing process means that the OPC belt surface is exposed to the laser beam to form
an electrostatic latent image.
(1) Structure of scanner unit
i) The scanner unit is located as shown in Fig.4-8.
ii) The source of the laser beam is a semiconductor laser.
iii) The laser light is scanned onto the OPC belt by converting the laser light to a beam
of light through the lens and reflective mirror to form an electrostatic latent image.
(2) Process of exposing (Refer to Fig.4-13.)
i) The OPC belt surface has been charged to the potential -Vo (V) in the charging
process.
ii) The laser light is scanned at right angles to the forward direction of the OPC belt.
iii) High speed switching of the laser is made according to the transmitted image data.
iv) The charge of the areas radiated by the laser light is reduced to the potential -VR
(V).
v) An invisible electrostatic latent image is formed on the OPC belt as shown in Fig. 4-
13.
-V
O
Exposing
Charging
Fig. 4-13
4-13
HL-3450CN SERVICE MANUAL
-V
R