Laser Exposure Mechanism - Gestetner B070 Service Manual

LASER EXPOSURE

6.10.2 LASER EXPOSURE MECHANISM

[C]
The LD unit consists of two 4-channel LDA's (Laser Diode Arrays) and two
collimating lenses.
Each LDA produces 4 beams [A]. Each collimating lens [B] is a fixed lens, seated
in a V-groove and held in place by a spring and a screw.
Four beams from each LDA [C] pass through the collimating lenses, though the
apertures [D], then strike the polygonal mirror. Due to this multi-beam writing, the
polygonal mirror motor speed can be reduced, thus the noise generated by the
polygon mirror motor and the wear on the motor can be reduced.
Auto Power Control (APC)
A built-in photo diode detects the light emitted from the LD unit. When the photo
diode detects this light, it generates a signal and the feedback of this signal to the
LD control board is used to adjust the strength and amount of light in the laser
beams.
NOTE: The laser diode array is assembled and adjusted in the factory, and
does not require physical position adjustment in the field.
LD drivers control the power output from the laser diodes.
( Digital Processes > Printing > Laser Printing > Laser Diode Power Control)
NOTE: The reference levels are adjusted on the production line. Never touch the
variable resistors on the LD unit.
B070/B071
CÓPIA NÃO CONTROLADA
6-50
CÓPIA NÃO CONTROLADA
[D]
[A]
[B]
B070D102.WMF
SM