Head Temperature Sensor - Citizen CLP-621 Technical Manual

IC11
Custom IC
CN8
9
SENS_A
97
PM2
10
SENS_B
98
PM3
[Main PCB]

(3-4) Head temperature sensor

The head temperature sensor is used to detect the temperature of the thermal head. This
sensor is a thermistor incorporated in the Head SA. Since the resistance of the thermistor
changes according to the temperature change, the voltage at pin 7 (HDTMP) of IC1 (CPU)
changes accordingly. The CPU senses the voltage at pin 7 to detect the head temperature.
According to the temperature of the print head, the CPU controls the printing pulse width
applied to the thermal elements to keep the printing density constant.
IC1
CPU
ANI2
Printing operation at the head temperature rise:
When the head temperature reaches 65 ° C (149 ° F), printing stops after printing the current
label. In this case, PRINT LED and CONDITION LED simultaneously blink on the
operation panel. When the temperature of the Head SA falls below 55 ° C (131 ° F), LEDs
stop blinking and printing resumes.
CN701
IC708A
R728
17
2
4
18
IC707A
7
(Same as above circuit)
[Ribbon Main PCB]
7
HDTMP
R85
Normal speed
55 ° C
Normal speed
(131 ° F)
+3.3V +3.3V
CN704
R727
1
2
C719
3
C720
4
6
CN705
1
2
3
4
CN4
+3.3V
19
HDTHM1
21
HDTHM2
5,6,8,11,12,20,22
[Main PCB]
Normal speed
(Stop)
2-25
2-2. Operation of Control Parts
Take-up side
CN901
+3.3V
R901 Tension Sensor
1
2
C901
3
C902
4
+3.3V
D901
R902
[Tension Sensor PCB]
Supply side
CN901
1
2
(Same as above circuit)
3
4
[Tension Sensor PCB]
Thermal Head
Head Temp.
Thermistor
(Stops)
65 ° C
(149 ° F)
CLP-621 & CLP-631
PI901