Laser Exposure Process; Laser Emission Timing - Konica Minolta bizhub C250 Service Manual

8. Write section (PH section)
8.2.2

Laser exposure process

1. Laser beam irradiated by the laser diode is reflected on the polygon mirror.
2. The polygon mirror is a four-faced mirror that rotates at high speed motored by the
polygon motor. The polygon mirror reflects the incoming laser beam in the main
scanning direction and reflects it on the G1 lens.
3. The G1 lens corrects the converging angle of the incoming laser beam and reflects
it on the return mirror 1.
4. Return mirror 1 reflects the laser beam collected by the G1 lens to the G2 lens.
5. G2 lens reflects the laser beam collected by the return mirror 1 on the return mirror
2.
6. The return mirror 2 irradiates the laser beam came from G2 lens to the PC drum.
Return mirror 2
SOS sensor
8.2.3

Laser emission timing

• When a ready signal is detected after the lapse of a given period of time after the print
cycle has been started, a laser ON signal is output from the mechanical control board
(PWB-M).
• The laser ON signal triggers the firing of each laser light which illuminates the SOS
Board via polygon mirror and G1 lens. This generates an SOS signal.
• This SOS (start of scan) signal unifies the timing at which the laser lights are irradiated
for each main scan line.
26
Polygon motor
Laser diode
Theory of operation ver. 3.0 Aug. 2006
SOS mirror
Return mirror 1
G2 lens
4038T2C028AA
G1 lens