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(5) Heater lamp control circuit
a. Outline
The heater lamp control circuit detects the heat roller surface tempera-
ture, and converts the temperature into a voltage. The converted volt-
age is inputted to the CPU.
IC26
1
16
(1-A2)
PMCLK
1B
1C
2
15
(2-C1)
MRPS1
2B
2C
3
14
(2-D1)
MRPS2
3B
3C
4
13
(2-D1)
MRPS3
4B
4C
5
12
(2-C1)
LDEN
5B
5C
6
11
(2-D1)
HL
6B
6C
7
10
(5-E3)
FTH
7B
7C
8
9
G
NC
KID65503F
[High temperature protection circuit in case of CPU hung up
(uncontrollable)]
For IC22 3Pin (reference voltage), +3.3V is divided by the resistor. The
thermistor terminal voltage is inputted to IC22 2Pin. When, therefore,
the voltage at 2Pin falls below the voltage at 3Pin, IC22 1Pin becomes
"H" and the HL signal is pulled to the GND level, suppressing genera-
tion of the lighting signal of the heater lamp. (IC22 output 1Pin is nor-
mally Low.)
[When the heat roller surface temperature is lower than the set
level]
a. When the thermistor terminal voltage is higher than the set level,
the output signal HL from ASIC becomes HIGH level.
b. This HL signal becomes the HLOUT signal through IC26, and is
inputted to the photo triac coupler in the power PWB. When, there-
fore, the HL signal is HIGH, the internal triac turns on.
c. When the internal triac turns on, the heater lamp lights up.
[When the heat roller surface temperature is higher than the set
level]
a. When the thermistor terminal voltage falls below the set level, the
output signal HL from ASIC becomes LOW level.
b. The HL signal becomes LOW, the power PWB photo triac coupler
turns OFF, and the heater lamp turns OFF.
(11-C1)
RTH_IN
INT5V
D4
1SS355
Q2
KRA119S
PMCLK_A
(11-B2)
MRPS_1
(6-A1)
2
MRPS_2
(6-A1)
MRPS_3
(6-A1)
3
/LDEN
(11-B2)
R86
R87
240J
240J
AR-M150/M155/M155X ELECTRICAL SECTION 13 - 8
The CPU converts the inputted analog voltage into a digital value. The
digital conversion value and the set value of the test command are
compared to control ON/OFF of the heater lamp according to the level,
controlling the heat roller surface temperature to be the fixed level.
VCC3
R66
R67
R68
1kF
1MF
7.5kF
3
D1
1
2
2
MA700
R70
R71
10kF
4.3kF
VCC3
D2
1
3
2
KDS226
3
2
C111
22000p
VCC3
R83
1.2kF
5
6
R85
10kF
HLOUT
(10-B3)
[When the thermistor is open]
The voltage at IC22 6Pin becomes higher than the voltage at 5Pin, and
the 7Pin output THOPEN becomes LOW. This is inputted to the CPU
to display the trouble code H2.
(6) Driver circuit (Clutch, solenoid)
Since a load cannot be directly driven by each load signal from the
CPU or the ASIC, each load is driven through the driver IC (transistor
array).
A large drive current (load current) is ordained from a small input cur-
rent (ASIC output current).
When the driver input voltage (base resistor input) is HIGH, the transis-
tor turns ON to flow a current through the load, operating the load.
ASIC/CPU
OUT PUT
12V
VCC3
R69
1kJ
IC22A
KIA393F
+
1
-
12V
C110
0.1u
VCC3
D3
1
12V
3
2
KDS226
IC24A
KIA358F
R81
R82
+
300J
100J
1
1
2
1
2
-
C112
12V
0.1u
C113
0.1u
12V
5V
R84
10kJ
IC22B
KIA393F
+
7
-
C114
22000p
FTH
(5-B2)
RTH
(1-A3)
THOPEN
(4-A4)
+24V
LOAD
LOAD
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