Oki B930 Service Manual page 12

OPTION EXIT2
OPTION DUPLEX
HSG ASSY-BTR
MSI
In the exposure step, the negatively charged drum surface is scanned by a laser beam. The laser
diode of the ROS (Raster Output Scanner) passes through a rotating polygon mirror (6 facets)
and lens scanning the drum from one end to the other.
The radiation of the laser beam varies according to a video signal from the PWBA ESS.
The laser beam shot at the drum excites electrons directed to the photo conductor. As a result,
electron-hole pairs are induced in the photoconductive layer. Since electrons are moved toward
the body inside the drum by the electric field, the electron-hole pairs move to the surface of the
photoconductive layer. Negative charges in the portion decrease, thus creating an invisible elec-
trostatic latent image there.
Toner particles are adsorbed onto this electrostatic latent image in the next step. Thus, the image
is developed. The toner particles adsorbed to the drum are attracted to positive charges supplied
by the BTR, and are transferred to the paper. The drum is sent for detack and cleaning steps.
• Electrostatic latent image formed on drum
FUSER ASSY
TRAY 1
TRAY 2
TRAY 3
TRAY 4
2-3
DRUM
CRU
OPTION
TRAY MODULE
FI61003A1