70
OP-P1/MF1 Training
Slide 70
Laser Unit Operation (3)
After the laser beam is reflected from the polygonal mirror,
it passes through the F-theta lens [7].
The first mirror [8] and shield glass [9] above the slit on the
bottom of the laser unit deflect the laser beams from the F-
theta lens downward onto the photoconductive surface of
the drum.
The angles between the beams that form the image elements are equal.
However, if the beams are projected without adjustment, the diameters of each
element projected onto the drum surface may be different (wide at the ends and
narrow at the center).
The F-theta lens corrects each beam so that it is projected onto the drum surface
at a constant speed and deflects the beam slightly inward to ensure that the
diameters of each picture element are all equal.
