Sharp AR-RF3 (serv.man2) Service Manual ▷ View online
AR-RF3 ELECTRICAL SECTION 8 - 3
4. Signal list
Signal name
Name
Function/Operation
AOSW
ADF open switch
Detects ADF open.
DEM
Reverse motor
Reverses or discharges documents.
DEOS
Paper exit open sensor
Detects opening of the paper exit cover.
DES
Paper exit sensor
Detects that a document has been transported to the paper exit sensor section.
DFM
Paper feed motor
Feeds a document from the tray.
DFOS
Paper feed open sensor
Detects opening of the paper feed cover.
DFSW
Paper feed open switch
Detects opening of the paper feed cover.
DLS1
Tray document length sensor 1
Detects the document length on the tray. (Short)
DLS2
Tray document length sensor 2
Detects the document length on the tray. (Long)
DRS
Reverse sensor
Detects that a document has been transported to the reverse sensor section.
DRSOL
Reverse solenoid
Switches the flapper in duplex operation.
DTM
Transport motor
Transports a document on the document glass,
DWVR
Document width detection volume
Detects the document width on the tray.
EMPS
Empty sensor
Detects document presence on the paper feed tray.
FOS
ADF front open sensor
Detects opening of ADF.
REGS
Resist sensor
Detects that a document has been transported to the resist roller sensor section.
TIMS
Timing sensor
Detects that a document has been transported to the timing sensor section.
AR-RF3 EXPLANATION OF ELECTRICAL SECTION 9 - 1
[9] EXPLANATION OF ELECTRICAL
SECTION
1. Operations
A. Sensor input circuits
(1) Original width detect volume (DWVR)
DWVR uses the volume.
The original width is detected by the output voltage change when the
volume knob is in the stop position.
volume knob is in the stop position.
The signal is input to the CPU (pin IC6-110) via noise filter R57 and
C48.
C48.
A-(1) Original volume input circuit
(2) Original length sensor 1 (DLS1)
DLS1 uses a photo interrupter composed of an LED and phototransis-
tor integrated into a single body.
tor integrated into a single body.
It detects the presence of an original in the tray using a lever-type actu-
ator.
ator.
When an original is present, the light path is obstructed.
The signal is input to the CPU (pin IC6-111) via noise filter RA20.1 and
C34.
C34.
A HIGH signal indicates that an original is present; a LOW signal
means no original.
means no original.
R36 is the current limiting resistance of the LED, and R20.2 is the load
resistance of the sensor.
resistance of the sensor.
A-(2) Original length sensor 1 input circuit
(3) Original length sensor 2 (DLS2)
DLS2 uses a photo interrupter composed of a light-emitting diode and
phototransistor integrated into a single body.
phototransistor integrated into a single body.
It detects the presence of an original in the tray using a lever-type actu-
ator.
ator.
When an original is present, the light path is obstructed.
The signal is input to the CPU (pin IC6-112) via noise filter RA20.4 and
C56.
C56.
A HIGH signal indicates that an original is present; a LOW signal
means no original.
means no original.
R74 is the current limiting resistance of the LED, and R20.3 is the load
resistance of the sensor.
resistance of the sensor.
A-(3) Original length sensor 2 input circuit
(4) Document feed open sensor (DFOS)
DFOS uses a photo interrupter composed of an LED and a phototrans-
istor integrated into a single body.
istor integrated into a single body.
It detects the open/closed status of the document feed cover using a
lever-type actuator.
lever-type actuator.
When the document feed cover is open, the light path is obstructed.
The signal is input to the CPU (pin IC6-96) via noise filter RA10.1 and
C49.
C49.
A HIGH signal indicates that the document feed cover is open; a LOW
signal means it is closed.
signal means it is closed.
R72 is the current limiting resistance of the LED, and R10.2 is the load
resistance of the sensor.
resistance of the sensor.
A-(4) Document feed open sensor input circuit
(5) Empty sensor (EMPS)
EMPS uses a photo interrupter composed of an LED and a phototrans-
istor integrated into a single body.
istor integrated into a single body.
It detects the presence of absence of an original in the tray using a
lever-type actuator.
lever-type actuator.
When the tray is empty, the light path is obstructed.
The signal is input to the CPU (pin IC6-97) via noise filter RA10.4 and
C50.
C50.
A LOW signal indicates that an original is present; a HIGH signal
means the tray is empty.
means the tray is empty.
R50 is the current limiting resistance of the LED, and R10.3 is the load
resistance of the sensor.
resistance of the sensor.
A-(5) Empty sensor input circuit
(6) Resist sensor (REGS)
REGS uses a photo interrupter composed of an LED and a phototrans-
istor integrated into a single body. When the original passes between
the sensor and the opposite mirror, the light path is obstructed and the
presence of the original is detected.
istor integrated into a single body. When the original passes between
the sensor and the opposite mirror, the light path is obstructed and the
presence of the original is detected.
The LED turns ON when the output from the CPU (pins IC6-98, IC6-
101 and IC6-102) goes through the DA converter (IC2), OP amp
(IC5.3) and transistor (Q9).
101 and IC6-102) goes through the DA converter (IC2), OP amp
(IC5.3) and transistor (Q9).
At the same time, the signal is input to the CPU (pin IC6-38) via noise
filter R54 and C63 and comparator (IC4.3).
filter R54 and C63 and comparator (IC4.3).
A HIGH signal indicates that an original is present; a LOW signal
means no original.
means no original.
Also, the analog input is sent to the CPU (pin IC6-107) without going
through the comparator.
through the comparator.
R68 and R71 split the voltage to provide the 5V reference voltage for
the comparator.
the comparator.
R59 is used to introduce hysteresis to the reference voltage.
A-(6) Resist sensor input circuit
Original width
volume
DWVR
volume
DWVR
Original
length
sensor 1
DLS1
length
sensor 1
DLS1
Original
length
sensor 2
DLS2
length
sensor 2
DLS2
Document
feed open
sensor
DFOS
feed open
sensor
DFOS
Original
empty
sensor
empty
sensor
Original resist sensor
AR-RF3 EXPLANATION OF ELECTRICAL SECTION 9 - 2
(7) Timing sensor (TIMS)
TIMS uses a reflection-type sensor composed of an LED and a pho-
totransistor integrated into a single body. When the original passes
between the sensor and the opposite mirror, the light path is
obstructed and the present of the original is detected.
totransistor integrated into a single body. When the original passes
between the sensor and the opposite mirror, the light path is
obstructed and the present of the original is detected.
The LED turns ON when the output from the CPU (pins IC6-98, IC6-
101 and IC6-102) goes through the DA converter (IC2), OP amp
(IC5.4) and transistor (Q8).
101 and IC6-102) goes through the DA converter (IC2), OP amp
(IC5.4) and transistor (Q8).
At the same time, the signal is input to the CPU (pin IC6-37) via noise
filter R55 and C64 and comparator (IC4.4).
filter R55 and C64 and comparator (IC4.4).
A HIGH signal indicates that an original is present; a LOW signal
means no original.
means no original.
Also, the analog input is sent to the CPU (pin IC6-106) without going
through the comparator.
through the comparator.
R15 and R69 split the voltage to provide the 5V reference voltage for
the comparator.
the comparator.
R4 is used to introduce hysteresis to the reference voltage.
A-(7) Timing sensor input circuit
(8) Original reverse sensor (DRS)
DRS uses a reflection-type sensor composed of an LED and a pho-
totransistor integrated into a single body.
totransistor integrated into a single body.
When the original passes between the sensor and the opposite mirror,
the light path is obstructed and the present of the original is detected.
the light path is obstructed and the present of the original is detected.
The LED turns ON when the output from the CPU (pins IC6-98, IC6-
101 and IC6-102) goes through the DA converter (IC2), OP amp
(IC5.2) and transistor (Q7).
101 and IC6-102) goes through the DA converter (IC2), OP amp
(IC5.2) and transistor (Q7).
At the same time, the signal is input to the CPU (pin IC6-34) via noise
filter R56 and C66 and comparator (IC4.1).
filter R56 and C66 and comparator (IC4.1).
A HIGH signal indicates that an original is present; a LOW signal
means no original.
means no original.
Also, the analog input is sent to the CPU (pin IC6-105) without going
through the comparator.
through the comparator.
R21 and R70 split the voltage to provide the 5V reference voltage for
the comparator.
the comparator.
R3 is used to introduce hysteresis to the reference voltage.
A-(8) Reverse sensor input circuit
(9) Document exit sensor (DES)
DES uses a photo interrupter composed of an LED and a phototransis-
tor integrated into a single body.
tor integrated into a single body.
The presence of a discharged original to the document exit tray is
detected using a lever-type actuator.
detected using a lever-type actuator.
When there is no original present, the light path is obstructed.
The signal is input to the CPU (pin IC6-128) via noise filter R21.1 and
C65.
C65.
A HIGH signal indicates that an original is present; a LOW signal
means no original.
means no original.
R58 is the current limiting resistance of the LED, and R21.2 is the load
resistance of the sensor.
resistance of the sensor.
A-(9) Document exit sensor input circuit
(10) Document exit cover sensor (DEOS)
DEOS uses a photo interrupter composed of an LED and a phototrans-
istor integrated into a single body.
istor integrated into a single body.
The open/closed status of the document exit cover is detected using a
lever-type actuator.
lever-type actuator.
When the document exit cover is open, the light path is obstructed.
The signal is input to the CPU (pin IC6-127) via noise filter RA21.4 and
C13.
C13.
A HIGH signal indicates that the document exit cover is open; a LOW
signal means it is closed.
signal means it is closed.
R15 is the current limiting resistance of the LED, and R21.3 is the load
resistance of the sensor.
resistance of the sensor.
A-(10) Document exit cover sensor input circuit
(11) Front open sensor (FOS)
FOS uses a photo interrupter composed of an LED and a phototransis-
tor integrated into a single body.
tor integrated into a single body.
The open/closed status of the front of the ADF is detected using a
lever-type actuator.
lever-type actuator.
When the front of the ADF is open, the light path is obstructed.
The signal is input to the CPU (pin IC6-88) via noise filter R17 and
C42.
C42.
A HIGH signal indicates that the ADF front is open; a LOW signal
means it is closed.
means it is closed.
R18 is the current limiting resistance of the LED, and R20 is the load
resistance of the sensor.
resistance of the sensor.
A-(11) Front open sensor input circuit
Original timing sensor
Original reverse sensor
Document
exit sensor
DES
exit sensor
DES
Document
exit cover
sensor
DEOS
exit cover
sensor
DEOS
Front open
sensor
FOS
sensor
FOS
AR-RF3 EXPLANATION OF ELECTRICAL SECTION 9 - 3
(12) ADF open switch (AOSW)
AOSW is a switch to detect the open/closed status of the ADF and
uses a microswitch.
uses a microswitch.
This switch is connected to +24V, and when the ADF is open, the con-
tact point opens and functions as a switch.
tact point opens and functions as a switch.
When the switch is turned ON, a +24V signal is applied to the ZD2
cathode, a base current is supplied to Q3, turning it ON, and the open/
closed signal is input to the CPU (pin IC6-74).
cathode, a base current is supplied to Q3, turning it ON, and the open/
closed signal is input to the CPU (pin IC6-74).
Also, C31 is for absorbing noise, and R23 is a pull-up resistor.
A HIGH signal indicates that the cover is open; a LOW signal means it
is closed.
is closed.
A-(12) ADF open SW input circuit
B. Reverse solenoid (DRSOL) drive circuit
DRSOL uses an open-frame solenoid.
The solenoid operates to switch the flapper, thus changing the path of
the original.
the original.
Solenoid ON: reverse. Solenoid OFF: not reverse.
The drive signal output from the CPU (pin IC6-72) is input to the gate
of the FET (Q2).
of the FET (Q2).
The drive signal (ON at HIGH level) controls the PWM, with ON DUTY
variable from 0 to 100% (255 levels).
variable from 0 to 100% (255 levels).
D1 works as a surge absorber when the solenoid is OFF.
R5 is used for protection of the CPU, and R26 is a pull-down resister.
B Reverse solenoid drive circuit
C. Indicator LED drive circuit
This is the drive circuit for the indicator LED that lights when an original
has been left on the original platform.
has been left on the original platform.
The drive signal output from the CPU (pin IC6-94) is sent to the transis-
tor (Q6).
tor (Q6).
A LOW signal from the CPU turns the LED ON; a HIGH signal turns it
OFF.
OFF.
C Indicator LED drive circuit
D. Motor drive circuits
(1) Document feed motor (DFM)
This circuit controls the DFM rotation, stop, rotation direction and motor
current. It is composed of the CPU (IC6), DA converter (IC2), constant
current chopper type driver IC (IC8), etc.
current. It is composed of the CPU (IC6), DA converter (IC2), constant
current chopper type driver IC (IC8), etc.
The stepping motor drive excitation pattern signal that is output from
the CPU (pins IC6-115 to IC6-118) controls the speed and direction of
the motor.
the CPU (pins IC6-115 to IC6-118) controls the speed and direction of
the motor.
The analog signal output from DA converter (pin IC2-10) is divided at
R38 and R40 to provide a fixed voltage.
R38 and R40 to provide a fixed voltage.
The current value for the motor is set when this split voltage is input to
pin IC8-3 and pin 14.
pin IC8-3 and pin 14.
D-(1) Feed motor drive circuit
(2) Original transport motor (DTM)
This circuit controls the DTM rotation, stop, rotation direction and motor
current. It is composed of the CPU (IC6), DA converter (IC2), constant
current chopper type driver IC (IC8), etc.
current. It is composed of the CPU (IC6), DA converter (IC2), constant
current chopper type driver IC (IC8), etc.
The stepping motor drive excitation pattern signal that is output from
the CPU (pins IC6-119 to IC6-122) controls the speed and direction of
the motor.
the CPU (pins IC6-119 to IC6-122) controls the speed and direction of
the motor.
The analog signal output from DA converter (pin IC2-2) is divided at
R61 and R42 to provide a fixed voltage.
R61 and R42 to provide a fixed voltage.
The current value for the motor is set when this split voltage is input to
pin IC9-3 and pin 14.
pin IC9-3 and pin 14.
D-(2) Transport motor drive circuit
ADF open
switch
switch
Reverse
solenoid
DRSOL
solenoid
DRSOL
Indicator LED
LED
LED
Feed MOT
DFM
DFM
Transport MOT
DTM
DTM
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