Gestetner A193 Service Manual page 446

LASER EXPOSURE
7. LASER EXPOSURE
7.1 OVERVIEW
The strength of the beam is 0.6 mW on the drum surface (10 mW output from
the LDDR board) at a wavelength of 780 nm.
The polygon motor speeds have been changed as follows:
Resolution (dpi)
400 dpi Copy and Fax
600 dpi Printer
391.16 dpi Fax (image rotation)
406.4 dpi Fax (mm printing)
The polygon mirror motor and motor driver are separated to prevent the laser
unit from being heated by the motor driver. Also, the laser unit has a polygon
motor cover and shield glass to reduce the noise from the polygon motor.
7.2 OPTICAL PATH
[I]
[C]
[D]
[B]
[I]
The shield glass has been added.
[A]: LD Unit
[B]: Polygon Mirror
[C]: Cylindrical Lens
[D]: Shield Glass
[E]: F - Theta Mirror
A224
Modes Motor Speed (rpm)
17952.8
26926.1
18240.0
17556.0
[B] [D] [F] [G] [E]
[F]
[F]: 1st Mirror
[G]: BTL
[H]: 2nd Mirror
[I]: Laser Syncronization Detector
13-12
Data Frequency (MHz)
11.750
26.438
11.674
11.674
[H]
[A]
[E]
[H]
G]
A224D501.wmf
SM