Sharp AL-1000 / AL-1010 (serv.man9) Service Manual ▷ View online
[7] OPERATIONAL DESCRIPTIONS
(1) Outline of operation
The outline of operation is described referring to the basic configuration.
(Basic configuration)
Outline of copy operation
Setting conditions
1) Set copy conditions such as the copy quantity and the copy density with the operation section, and press the COPY button.
The information on copy conditions is sent to the MCU.
Image scanning
2) When the COPY button is pressed, the scanner section starts scanning of images.
The light from the copy lamp is reflected by the document and passed through the lens to the CCD.
Photo signal/Electric signal conversion
3) The image is converted into electrical signals by the CCD circuit and passed to the MCU.
Image process
4) The document image signal sent from the CCD circuit is processed under the revised conditions and sent to the LSU (laser
unit) as print data.
Electric signal/Photo signal (laser beam) conversion
5) The LSU emits laser beams according to the print data.
(Electrical signals are converted into photo signals.)
6) The laser beams are radiated through the polygon mirror and various lenses to the OPC drum.
Printing
7) Electrostatic latent images are formed on the OPC drum according to the laser beams, and the latent images are developed
to be visible images (toner images).
8) Meanwhile the paper is fed to the image transfer section in synchronization with the image lead edge.
9) After the transfer of toner images onto the paper, the toner images are fused to the paper by the fusing section. The copied
9) After the transfer of toner images onto the paper, the toner images are fused to the paper by the fusing section. The copied
paper is discharged onto the exit tray.
Operation
section
Scanner section
CCD
MCU (Main control/image process section)
Laser beam
Paper exit
Fusing section
Paper transport section
Manual paper
feed section
Cassette paper
feed section
Printer section
LSU (Laser unit)
Laser diode, Polygon mirror lens
Laser diode, Polygon mirror lens
Process section
AL-1000/1010
7-1
(2) Scanner section
1) How to scan documents
The scanner has sensors that are arranged in a line. These sensors
scan a certain area of a document at a time and deliver outputs se-
quentially. When the line is finished, the next line is scanned, and this
procedure is repeated. The figure below shows the case where the lat-
ter two sections of an image which are scanned are shown with solid
lines and the former two sections which are being transmitted are
shown with dotted lines.
The direction of this line is called “main scanning direction,” and the
scanning direction “sub scanning direction.”
In the figure above, one line is divided into 4 sections. Actually, how-
ever, one line is divided into thousands of sections. For scanning, the
light receiving element called CCD is used.
The basic resolution indicates the scanner capacity. The basic resolu-
tion is expressed in dpi (dot/inch) which shows the number of light
emitting elements per inch on the document.
The basic resolution of this machine is 400dpi.
In the sub scanning direction, at the same time, the motor that drives
the optical system is controlled to scan the image at the basic resolu-
tion.
scan a certain area of a document at a time and deliver outputs se-
quentially. When the line is finished, the next line is scanned, and this
procedure is repeated. The figure below shows the case where the lat-
ter two sections of an image which are scanned are shown with solid
lines and the former two sections which are being transmitted are
shown with dotted lines.
The direction of this line is called “main scanning direction,” and the
scanning direction “sub scanning direction.”
In the figure above, one line is divided into 4 sections. Actually, how-
ever, one line is divided into thousands of sections. For scanning, the
light receiving element called CCD is used.
The basic resolution indicates the scanner capacity. The basic resolu-
tion is expressed in dpi (dot/inch) which shows the number of light
emitting elements per inch on the document.
The basic resolution of this machine is 400dpi.
In the sub scanning direction, at the same time, the motor that drives
the optical system is controlled to scan the image at the basic resolu-
tion.
2) Basic structure of scanner section
1
Copy lamp (Xenon lamp)
2
Reflector (light conversion plate)
3
No. 1 mirror
4
No. 2 mirror
5
No. 3 mirror
6
Lens
7
No. 2/3 mirror unit
8
Copy lamp unit
9
CCD
10
Mirror motor
11
MHPS (Mirror home position sensor)
The scanner unit performs scanning in the digital optical system.
The light from the light source (Xenon lamp) is reflected by a document and passed through three mirrors and reduction lenses to
the CCD element (image sensor) where images are formed. This system is known as the reduction image sensor system. Photo ener-
gy on the CCD element is converted into electrical signals (analog signals). (Photo-electric conversion). The output signals (analog
signals) are converted into digital signals (A/D conversion) and passed to the MCU (main control/image process section). The resolu-
tion at that time is 400dpi.
The mirror unit in the scanner section is driven by the mirror motor.
The MHPS is provided to detect the home position of the copy lamp unit.
The light from the light source (Xenon lamp) is reflected by a document and passed through three mirrors and reduction lenses to
the CCD element (image sensor) where images are formed. This system is known as the reduction image sensor system. Photo ener-
gy on the CCD element is converted into electrical signals (analog signals). (Photo-electric conversion). The output signals (analog
signals) are converted into digital signals (A/D conversion) and passed to the MCU (main control/image process section). The resolu-
tion at that time is 400dpi.
The mirror unit in the scanner section is driven by the mirror motor.
The MHPS is provided to detect the home position of the copy lamp unit.
(6)
(5)
(4)
(3)
(2)
(1)
(10)
(11)
(9)
(8)
(7)
1
2
3
4
5
5
4
3
2
1
Sub scanning direction
Sensor scanning area
Main
scanning
direction
scanning
direction
Original
Image data sent to the ICU PWB
To MCU PWB
AL-1000/1010
7-2
(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.
sent to the LSU (laser unit), where it is converted into laser
beams.
1) Basic structure
The LSU unit is the writing section of the digital optical system.
The semiconductor laser is used as the light source, and im-
ages are formed on the OPC drum by the polygon mirror and
f
The semiconductor laser is used as the light source, and im-
ages 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
cylindrical lens, the polygon mirror, the f
θ
lens, and the mirror
to form images on the OPC drum in the main scanning direc-
tion. The laser emitting PWB is provided with the APC (auto
power control) in order to eliminate fluctuations in the laser
power. The BF PWB works for measurement of the laser writ-
ing start point.
tion. The laser emitting PWB is provided with the APC (auto
power control) in order to eliminate fluctuations in the laser
power. The BF PWB works for measurement of the laser writ-
ing start point.
No.
Component
Function
(1)
Semiconductor laser
Generates laser beams.
(2)
Collimator lens
Converges laser beams in
parallel.
parallel.
(3)
Polygon mirror,
polygon motor
polygon motor
Reflects laser beams at a
constant rpm.
constant rpm.
(4)
BD (Mirror, lens,
PWB)
PWB)
Detects start timing of laser
scanning.
scanning.
(5)
f
θ
lens
Converges laser beams at a
spot on the drum.
spot on the drum.
Makes the laser scanning
speeds at both ends of the
drum same as each other.
(Refer to the figure below.)
speeds at both ends of the
drum same as each other.
(Refer to the figure below.)
Makes the laser scanning speeds at both ends of the drum
same as each other.
same as each other.
2) Laser beam path
3) Composition
Effective scanning width: 216mm (max.)
Resolution:
600dpi
Beam diameter:
75um in the main scanning
direction, 80um in the sub
scanning direction
direction, 80um in the sub
scanning direction
Image surface power:
0.20
±
0.03mW (Laser
wavelength 780 – 795nm)
Polygon motor section:
Brushless motor 20.787rpm
No. of mirror surfaces: 6 surfaces
No. of mirror surfaces: 6 surfaces
(1)
(2)
(3)
(4)
(5)
: Laser beam
path for BF PWB
a
≠
b
≠
c
a
b
c
d = e = f
d
e
f
f
θ
LENS
AL-1000/1010
7-3
Fuser section
1. General description
General block diagram (cross section)
Top view
A. Heat roller
A pressure roller is used for the heat roller and a silicone rubber
roller is used for the lower heat roller for better toner fusing per-
formance and paper separation.
roller is used for the lower heat roller for better toner fusing per-
formance and paper separation.
B. Separator pawl
Three separator pawls are used on the upper heat roller. The
separator pawls are teflon coated to reduce friction with the
roller and prevent a smear on the paper caused by the
separator pawl.
separator pawls are teflon coated to reduce friction with the
roller and prevent a smear on the paper caused by the
separator pawl.
C. 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
purposes.
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
purposes.
2. The surface temperature of the upper heat roller is set to
165˚C
∼
190˚C. The surface temperature during the power
save mode is set to 100˚C.
3. The self-check function comes active when one of the fol-
lowing malfunctions occurs, and an "H" is displayed on the
multicopy window.
multicopy 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
d. Open thermal fuse
e. When the heat roller temperature does not reach 190˚C
within 27 second after supplying the power.
D. Fusing resistor
Fusing resistor
This model is provided with a fusing resistor in the fusing sec-
tion to improve transfer efficiency.
General descriptions are made in the following.
This model is provided with a fusing resistor in the fusing sec-
tion to improve transfer efficiency.
General descriptions are made in the following.
General descriptions
Since the upper heat roller is conductive when copy paper is
highly moistured and the distance between the transfer unit and
the fusing unit is short, the transfer current leaks through the
copy paper, the upper heat roller and the discharging brush.
Since the upper heat roller is conductive when copy paper is
highly moistured and the distance between the transfer unit and
the fusing unit is short, the transfer current leaks through the
copy paper, the upper heat roller and the discharging brush.
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 lamp.
(950W)
heater lamp.
(950W)
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)
AL-1000/1010
7-4
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