Read Sharp MX-M850 (serv.man18) Service Manual online
MX-M1100 LSU SECTION G – 2
2. Operational descriptions
This LSU emits 4 laser beams during 1200dpi mode and 2 laser beams during 600dpi mode.
The operation varies as below according to the model and the print mode. (resolution)
The operation varies as below according to the model and the print mode. (resolution)
(* 1):
The laser beam size is the same regardless of the print resolution 600dpi or 1200dpi, but the laser power varies.
When the laser beams are applied to the photoreceptor to form the electrostatic latent image, the more the laser power is, the larger the area of
the electrostatic latent image created by 1 dot of the laser beam becomes.
This occurs because of optical characteristics of the photoreceptor. The laser power of 600dpi is higher than 1200dpi, so the area of the elec-
trostatic latent image created by 1 dot of the 600dpi laser becomes larger than that of 1200dpi laser.
That effect prevents from creating difference in print density among images with different resolution.
The laser beam size is the same regardless of the print resolution 600dpi or 1200dpi, but the laser power varies.
When the laser beams are applied to the photoreceptor to form the electrostatic latent image, the more the laser power is, the larger the area of
the electrostatic latent image created by 1 dot of the laser beam becomes.
This occurs because of optical characteristics of the photoreceptor. The laser power of 600dpi is higher than 1200dpi, so the area of the elec-
trostatic latent image created by 1 dot of the 600dpi laser becomes larger than that of 1200dpi laser.
That effect prevents from creating difference in print density among images with different resolution.
3. Disassembly and assembly
A. LSU
(1) LSU
1)
Remove the left upper cabinet.
2)
Disconnect the connector (a),and remove the screw (b).
Remove the LSU (c).
Remove the LSU (c).
No
Name
Function
1
Scanning mirror (Polygon mirror motor)
Reflects the laser beam to expose the drum surface. Writes in the main scan direction.
2
Laser unit
Emits the laser beam.
3
No.1 cylindrical lens
Gathers the laser beams from the laser unit.
4
Incident mirror
Reflects the laser beams from the laser unit to send to the scanning mirror.
5
No.1 mirror
Reflects the laser beams from the scanning mirror to send to No.2 mirror.
6
No.2 mirror
Reflects the laser beams from No.1 mirror to send to No.3 mirror.
7
No.3 mirror
Reflects the laser beams from No.2 mirror to send to the photoreceptor.
8
No.2 cylindrical lens
Corrects the deflection caused by the tilted scanning mirror.
9
BD mirror
Guides the laser beams to BD PWB.
10
BD PWB
Detects the start timing of the laser scan.
Detects the troubles of laser beams.
Detects the troubles of laser beams.
11
f lens 2
Bends the laser beams to equalize the laser scanning pitches on the OC drum.
12
Filter glass
Prevents contamination of dusts and foreign material.
13
f lens 1
Bends the laser beams to equalize the laser scanning pitches on the OC drum.
14
Laser control PWB
Converts the image signals to video signals and laser beams.
Controls ON/OFF and output power of the laser.
Controls ON/OFF and output power of the laser.
15
Filter glass
Prevents contamination of dusts and foreign material from the outside.
16
Distortion adjustment cam
The cam for adjusting distortion of the print image.
Model
Number of
scanning
mirrors
Number of
revolutions of the
scanning mirror
Laser power
Number of laser beams
per scan
(Main scanning direction)
Laser beam
size (*1)
Laser beam pitch
(Main scanning
direction)
600 dpi
1200 dpi
600 dpi
1200 dpi
600 dpi
1200 dpi
85-sheet model
14 faces
20,247 rpm
0.21 mw
0.12 mw
2
4
60um
✕ 60um
42
μm
21
μm
95/100-sheet model
14 faces
27,334 rpm
0.28 mw
0.15 mw
2
4
60um
✕ 60um
42
μm
21
μm
Parts
Page
A
LSU
G - 2/(1)
B
Temperature humidity sensor 2
G - 3/(2)
A
B
a
a
b
b
c
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