Kyocera DISCOVER FS-3830N, Service Manual

Page: 129 / 176

2FP/2FY/2FR-2
2-1-11
Laser scanner unit
Figure 2-1-11 Laser scanner unit
1. Laser diode .................................................. Emits diffused, visible laser.
2. Collimator lens ............................................. Aligns the laser beam to the cylindrical lens.
3. Cylindrical lens ............................................. Compensates the vertical angle at which the laser beam hits on of the
polygon mirror segments.
4. Polygon mirror (motor) ................................. Has six mirror segments around its hexagonal circumference. Each
mirror corresponds to one scanned line width on the drum when the
laser beam scans on it.
5. Primary f-theta lens ...................................... See figure 2-1-11 above.
6. Secondary f-theta lens ................................. 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 2-1-11 above, 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).
7. Diversion mirror ............................................ Diverts the laser beam vertically onto the drum. Note the diffused laser
beam finally pinpoints on the drum.
8. Protective glass ............................................ Prevent dust, debris, etc., from entering the scanner assembly.
9. Sensor mirror ............................................... Bends the very first shot of a laser scan towards the pin photo sensor
(See figure 2-1-11).
10. Pin photo sensor .......................................... When shone by the sensor mirror above, this pin photo sensor
generates a trigger signal.
11. Heat sink ...................................................... Cooling polygon motor.
1
2
3
4
5
10
11
6
9
7
8
Primary
f-theta lens
Laser diode
Polygon mirror
Drum
Laser beam
Secondary
f-theta lens
Laser scanner unit (LSU)