Kyocera FS-1800 Service Manual page 84

Name
5 Primary f-theta lens
6 Secondary f-theta lens
7 Diversion mirror
8 Protective glass
9 Sensor mirror
0 Pin photo sensor
See figure 4-1-7 below.
The primary (above) and secondary f-theta lenses equalize focusing
distortion on the area on the drum closer to the edge. The effective
length of line (A, B in the figure below) the laser beam draws on
the drum becomes longer as the laser beam hits closer to the drum
edge. In the figure 4-1-7 below, distances represented by A and B
are not the same (A > B) until the f-theta lenses are provided between
the polygon mirror and the drum (A = B).
Diverts the laser beam vertically onto the drum. Note the diffused
laser beam finally pinpoints on the drum.
Prevent dust, debris, etc., from entering the scanner assembly.
Bends the very first shot of a laser scan towards the pin photo sensor
(below).
When shone by the sensor mirror above, this pin photo sensor
generates a trigger signal.
Laser beam
Figure 4-1-7 F-theta lens
4-9
Description
Polygon mirror
Laser diode
Primary f-theta lens
Secondary f-theta lens
Drum
FS-1800/1800N | FS-3800/3800N