AR-122E (serv.man12). Sect 7. Operational Description - Sharp Copying Equipment Service Manual (repair manual). Page 3

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AR-122E/152E/153E/157E  OPERATIONAL DESCRIPTIONS  7 - 3
3. Laser unit
The image data sent from the MCU (image process circuit) is sent to
the LSU (laser unit), where it is converted into laser beams.
A. Basic structure
The LSU unit is the writing section of the digital optical system.
The semiconductor laser is used as the light source, and images are
formed on the OPC drum by the polygon mirror and f
θ
 lens, etc.
The laser beams are passed through the collimator lens, the cylindrical
lens, the polygon mirror, the f
θ
 lens, and the mirror to form images on
the OPC drum in the main scanning direction. The laser emitting PWB
is provided with the APC (auto power control) in order to eliminate fluc-
tuations in the laser power. The BD PWB works for measurement of
the laser writing start point.
Makes the laser scanning speeds at both ends of the drum same as
each other.
B. Laser beam path
C. Composition
Effective scanning width: 216mm (max.)
Resolution: 600dpi
Beam diameter: 75um in the main scanning direction, 80um in the sub
scanning direction
Image surface power: 0.17 ±0.01mW (Laser wavelength 770 - 795nm)
Polygon motor section: Brushless motor 20.787rpm
No. of mirror surfaces: 6 surfaces
4. Fuser section
No
 Component
Function
1
Semiconductor laser
Generates laser beams.
2
Collimator lens
Converges laser beams in parallel.
3
Polygon mirror, 
polygon motor
Reflects laser beams at a constant rpm.
4
BD (Mirror, lens, PWB) Detects start timing of laser scanning.
5
f
θ
 lens
Converges laser beams at a spot on the 
drum.
Makes the laser scanning speeds at both 
ends of the drum same as each other. 
(Refer to the figure below.)
1
2
3
4
5
≠ 
≠ 
c
a
b
c
d = e = f
d
e
f
 
f
θ 
LENS
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