Table of Contents
Advertisement
[When the heat roller surface temperature becomes
higher than the set level]
a. Since the thermistor pin voltage is lower than the set level, the
output signal HL from the CPU becomes LOW.
b. The HL signal becomes LOW, SSR is OFF, the external triac is
OFF, and the heater lamp is OFF.
[Q206]
This prevents the heater lamp from being always kept ON by the
improper treatment of the harness for the heater lamp drive signal.
(5) Driver circuit (Solenoid, magnetic clutch)
1
Outline
The control signals of the loads outputted from the CPU I/O are
unable to drive loads directly. They are passed through the driver IC
to each load.
2
Operation
The driver circuit composes the Darlington circuit with two transistors.
By this circuit, a great drive current is obtained from a small input
current (I/O output current). When the driver input voltage is HIGH
(+5V), the transistor turns on to flow a current in the arrow direction to
operate the loads. When the driver is on, the driver output pin voltage
is 0V.
I/O
output
(6) Stepping motor drive circuit
1
Outline
The driver circuit drives the auto duplex copy tray side plate motor
and the rear edge motor.
A: Stepping motor A phase coil drive signal
B: Stepping motor B phase coil drive signal
A: Stepping motor A phase coil drive signal
B: Stepping motor B phase coil drive signal
A
Phase A
+24V
Phase A
A
+24V
LOAD
Phase B Phase B
B
+24V
B
Stepping motor time chart
A
B
A
B
Drive signal
A
B
A
B
(7) Toner supply motor drive circuit
The IC111 is used to control the motor and to drive the toner supply
motor with the pulse signals (TMa, TMb) outputted from the I/O chip.
TMa
TMb
I/O
R242
47KJ
Internal circuit
+5V
2
8
REG
Protection
circuit
(Heat insulation)
9
1
TMa
TMb
Truth value table
Input
TMa
TMb
L
L
H
L
L
H
H
H
∞
: High impedance
9 – 15
Side plate motor
Rear edge motor.
PAM1-0
PAM2-0
PAM1-1
PAM2-1
PAM1-2
PAM2-2
PAM1-3
PAM2-3
+24V
IC111
+
2
6
+5V
9
8
IN1
1
7
TMa
IN2
5
3
TMb
GND
R245
TA7291S
47KJ
+24V
6
7
3
5
GND
(4) pin is NC pin.
Output
Mode
TMa
TMb
∞
∞
Stop
H
L
CW/CCW
L
H
CCW/CW
L
L
Brake
C101
10UF35V
M
+24V
TMa
M
TMb
Advertisement
Table of Contents
