Kyocera Mita FS-6750 Service Manual page 64

Figure 4.3 Laser scanner unit
Downverting mirror
Photo diode
Collimeter lens
Cylindorical lens
Table 4. 1 Function of scanner component—
Component
Laser diode
Collimeter lens
Cylindrical lens
Polygon mirror (motor)
Primary f-theta lens
Secondary f-theta lens
Diversion mirror
Protective glass
Sensor mirror
Beam detector sensor
Electrophotographics system
Secondary f-theta lens
Cover glass
Polygon mirror/motor
Function
Emits diffused, invisible laser.
Aligns the laser beam to the cylindrical lens.
Compensates the slant angle at which the laser beam hits a
polygon mirror segment.
Has five mirror segments around its octagonal circumference;
each mirror corresponding to one scanned line width on the
drum when laser beam scans on it.
See page 7, Figure 4.4 and below.
See page 7, Figure 4.4. The primary (above) and secondary
ftheta lenses equalize focusing distortion on the drum edges.
The effective length of line ("A," "B" below) the laser beam draws
on the drum becomes longer as the laser beam hits closer to the
drum edges. In the figure below, distances represented by "A"
and "B" are not the same (A>B) until the ftheta lenses are pro-
vided between the polygon mirror and the drum (A=B).
diverts the laser beam vertically onto the drum. Note the dif-
fused laser beam finally pin-points on the drum.
Prevents dust, debris, etc., from entering the scanner assembly.
Bends the very first shot of a laser scan towards the beam detec-
tion sensor (See next.).
When shone by the sensor mirror above, this photosensor gener-
ates a trigger signal for the engine controller to start activating
the paper feeding system.
4-6
Operation theory
Primary f-theta lens
FS-6750