Sharp MX-B201D (serv.man9) Service Manual ▷ View online
MX-B201/B201D OPERATIONAL DESCRIPTIONS 7 - 2
2. Scanner section
A. Scanner unit
The scanner unit in the digital copier scans images.
It is composed of the optical unit and the drive unit. The optical unit
performs scanning in the main scan direction with the light receiving
elements (color CCD). The drive unit performs scanning in the sub
scanning direction by moving the optical unit.
performs scanning in the main scan direction with the light receiving
elements (color CCD). The drive unit performs scanning in the sub
scanning direction by moving the optical unit.
B. Optical system
Two white lamps are used as the light source.
Light radiated from the light source is applied to the document on
the document table. The reflected light from the document is
reflected 4 times by No. 1 - No. 3 mirrors and passed through the
reduction lens to form images on the light-receiving surface of 3-line
CCD.
the document table. The reflected light from the document is
reflected 4 times by No. 1 - No. 3 mirrors and passed through the
reduction lens to form images on the light-receiving surface of 3-line
CCD.
The light-receiving surface of the color CCD is provided with 3 line
scanning sections for RGB. Separate images scanned in each color
section are overlapped to complete color scanning. (When PC
scanning)
scanning sections for RGB. Separate images scanned in each color
section are overlapped to complete color scanning. (When PC
scanning)
The resolution is 600dpi.
When copying, only the green component is used to print with the
printer.
printer.
The color component for printing can be switched to red or blue by
the service simulation.
the service simulation.
(Spectrum characteristics of the lamp)
(Spectrum characteristics of the color CCD)
(Optical unit)
C. Drive system
The drive system is composed of the scanner motor, the pulley
gear, the idle pulley, the idle gear, the belt 473, the belt 190, and the
shaft.
gear, the idle pulley, the idle gear, the belt 473, the belt 190, and the
shaft.
The motor rotation is converted into reciprocated movements of the
belt 473 through the idle gear, the pulley gear, the belt 190, and the
idle pulley to drive the optical unit.
belt 473 through the idle gear, the pulley gear, the belt 190, and the
idle pulley to drive the optical unit.
100
75
50
45.4
100.0
50.2
25
380
480
580
680
780
Wavelength [nm]
Sensitivity
1
Table glass
2
Optical unit
3
Lens
4
Mirror 1
5
Mirror 2
6
Mirror 3
7
CCD PWB
8
Lamp
9
Reflector
10
Original
Spectral sensitivity characteristics (Standard characteristics)
Relative sensitivity
Wavelength [nm]
8
9
9
10
1
7
5
3
4
2
6
7
9
3
4
6
2
8
5
1
3
1
Scanner motor
2
Pulley gear
3
Idle pulley
4
Belt 473
5
Belt 190
6
Optical unit
7
Shaft
8
Idle gear
9
Table glass
MX-B201/B201D 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.
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
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 cylin-
drical lens, the polygon mirror, the f
drical 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 fluctuations in the laser power. The BD PWB works for
measurement of the laser writing start point.
emitting PWB is provided with the APC (auto power control) in order
to eliminate fluctuations 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.
each other.
B. Laser beam path
C. Composition
Effective scanning width: 216mm (max.)
Resolution: 600dpi
Beam diameter: 75um in the main scanning direction, 85um in the
sub scanning direction
sub scanning direction
Image surface power: 0.16 ± 0.01mW (Laser wavelength 770 -
795nm)
795nm)
Polygon motor section: Brushless motor 35433rpm
No. of mirror surfaces: 5 surfaces
No. of mirror surfaces: 5 surfaces
4. Fuser section
No
Component
Function
1
Semiconductor laser
Generates laser beams.
2
Collimator lens
Converges laser beams in parallel.
3
Cylinder lens
Takes the focus.
4
Polygon mirror,
polygon motor
polygon motor
Reflects laser beams at a constant
rpm.
rpm.
5
BD (Lens, PWB)
Detects start timing of laser
scanning.
scanning.
6
f
θ lens
Converges laser beams at a spot on
the drum.
the drum.
Makes the laser scanning speeds at
both ends of the drum same as each
other. (Refer to the figure below.)
both ends of the drum same as each
other. (Refer to the figure below.)
2
3
3
6
4
1
5
6
a
≠ b ≠ c
a
b
c
d = e = f
d
e
f
f
θ
LENS
MX-B201/B201D OPERATIONAL DESCRIPTIONS 7 - 4
A. General description
General block diagram (cross section)
Top view
(1)
Heat roller
A Teflon roller is used for the heat roller and a silicone rubber roller
is used for the lower heat roller for better toner fusing performance
and paper separation.
is used for the lower heat roller for better toner fusing performance
and paper separation.
(2)
Separator pawl
Three separator pawls are used on the upper heat roller. The sep-
arator pawls are Teflon coated to reduce friction with the roller and
prevent a smear on the paper caused by the separator pawl.
arator pawls are Teflon coated to reduce friction with the roller and
prevent a smear on the paper caused by the separator pawl.
(3)
Thermal control
1) The heater lamp, thermistor, main PWB, DC power supply
PWB, and triac within the power supply unit are used to control
the temperature in the fuser unit.
To prevent against abnormally high temperature in the fuser
unit, a thermal breaker and thermal fuse are used for safety pur-
poses.
the temperature in the fuser unit.
To prevent against abnormally high temperature in the fuser
unit, a thermal breaker and thermal fuse are used for safety pur-
poses.
2) The surface temperature of the upper heat roller is set to 160 -
200°C. The surface temperature during the power save mode is
set to 100°C.
set to 100°C.
3) The self-check function comes active when one of the following
malfunctions occurs, and an "H" is displayed on the multicopy
window.
window.
a. When the heat roller surface temperature rises above 240°C.
b. When the heat roller surface temperature drops below 100°C
during the copy cycle.
c. Open thermistor
d. Open thermal fuse
e. When the heat roller temperature does not reach 190°C within
27 second after supplying the power.
(4) Fusing resistor
This model is provided with a fusing resistor in the fusing section
to improve transfer efficiency.
to improve transfer efficiency.
Since the upper heat roller is conductive, when using copy paper
that contains moisture and the distance between the transfer unit
and the fusing unit is short, the transfer current may find a path to
ground via the copy paper, the upper heat roller and the discharg-
ing brush.
that contains moisture and the distance between the transfer unit
and the fusing unit is short, the transfer current may find a path to
ground via the copy paper, the upper heat roller and the discharg-
ing brush.
5. Paper feed section and paper
transport section
A. Paper transport path and general operations
Paper feed is made in two ways; the tray paper feed and the man-
ual paper feed. The tray is of universal-type, and has the capacity
of 250 sheets.
ual paper feed. The tray is of universal-type, and has the capacity
of 250 sheets.
The front loading system allows you to install or remove the tray
from the front cabinet.
from the front cabinet.
The general descriptions on the tray paper feed and the manual
paper feed operation are given below.
paper feed operation are given below.
Separator pawl
PPD2
Thermal fuse
Thermistor
Heat roller
Paper guide
Pressure roller
Heat roller
Thermistor
Thermal fuse
Heater lamp
Separator pawl
Safety device
(thermal breaker, thermal
fuse)
(thermal breaker, thermal
fuse)
Triac (in the
power supply unit)
power supply unit)
Heated by the heater
The surface temperature
of the upper heat roller is
sensed by the thermistor.
of the upper heat roller is
sensed by the thermistor.
Level of the thermistor is
controlled by the main PWB.
controlled by the main PWB.
With the signal from the
main PWB, the triac is
controlled on and off.
(power supply PWB)
main PWB, the triac is
controlled on and off.
(power supply PWB)
lamp. (800W)
1
1
Scanner unit
8
Drum
2
Copy lamp
9
Transfer unit
3
LSU (Laser unit)
10
Pickup roller
4
Paper exit roller
11
Manual paper feed tray
5
Main charger
12
Manual paper feed roller
6
Heat roller
13
PS roller unit
7
Pressure roller
14
Paper feed roller
1
2
5
3
4
6
7
8
9
10
8
9
10
11
12
13
14
MX-B201/B201D OPERATIONAL DESCRIPTIONS 7 - 5
(1)
Cassette paper feed operation
1) The figure below shows the positions of the pick-up roller, the
paper feed clutch sleeve, and the paper feed latch in the initial
state without pressing the Start key after lighting the ready
lamp.
The paper feed latch is in contact with the projection of the
clutch sleeve.
state without pressing the Start key after lighting the ready
lamp.
The paper feed latch is in contact with the projection of the
clutch sleeve.
2) When the Start key is pressed, the main drive motor starts
rotating to drive each drive gear.
The pick-up drive gear also is driven at that time. Since, how-
ever, the paper feed latch is in contact with the projection of the
clutch sleeve, rotation of the drive gear is not transmitted to the
pick-up roller, which does not rotate therefore.
The pick-up drive gear also is driven at that time. Since, how-
ever, the paper feed latch is in contact with the projection of the
clutch sleeve, rotation of the drive gear is not transmitted to the
pick-up roller, which does not rotate therefore.
3) After about 0.1 sec from when the main motor start rotating, the
tray paper feed solenoid (PFS) turns on for a moment.
This disengages the paper feed latch from the projection of the
clutch sleeve, transmitting rotation of the pick-up drive gear to
the paper feed roller shaft, rotating the pick-up roller to feed the
paper.
This disengages the paper feed latch from the projection of the
clutch sleeve, transmitting rotation of the pick-up drive gear to
the paper feed roller shaft, rotating the pick-up roller to feed the
paper.
4) After more than half rotation of the pick-up roller, the paper feed
latch is brought in contact with a notch on the clutch sleeve,
stopping rotation of the pick-up roller.
stopping rotation of the pick-up roller.
5) At this time, the paper is fed passed the paper entry detection
switch (PPD1), and detected by it. After about 0.15 sec from
detection of paper by PPD1, the tray paper feed solenoid (PFS)
turns on so that the clutch sleeve projection comes into contact
with the paper feed latch to stop the pick-up roller. Then the
pick-up roller rotates for about 0.15 sec so that the lead edge of
the paper is evenly pressed on the resist roller, preventing
against skew feeding.
detection of paper by PPD1, the tray paper feed solenoid (PFS)
turns on so that the clutch sleeve projection comes into contact
with the paper feed latch to stop the pick-up roller. Then the
pick-up roller rotates for about 0.15 sec so that the lead edge of
the paper is evenly pressed on the resist roller, preventing
against skew feeding.
6) To release the resist roller, the tray paper feed solenoid and the
resist solenoid are turned on by the paper start signal to disen-
gage the resist start latch from the clutch sleeve, transmitting
rotation of the resist drive gear to the resist roller shaft. Thus the
paper is transported by the resist roller.
gage the resist start latch from the clutch sleeve, transmitting
rotation of the resist drive gear to the resist roller shaft. Thus the
paper is transported by the resist roller.
7) After the resist roller starts rotating, the paper is passed through
the pre-transfer guide to the transfer section. Images are trans-
ferred on the paper, which is separated from the OPC drum by
the drum curve and the separation section.
ferred on the paper, which is separated from the OPC drum by
the drum curve and the separation section.
8) The paper separated from the drum is passed through the fus-
ing paper guide, the heat roller (fusing section), POD (paper out
detector) to the copy tray.
detector) to the copy tray.
OFF
PFS
OFF
RRS
OFF
PFS
OFF
RRS
ON
PFS
OFF
RRS
OFF
PFS
ON
RRS
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