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Operation of Control Parts
(3) Ribbon Sensor F/R
The ribbon sensor F ("SA, Ribbon Sensor" mounted on the front side) is used to detect the
ribbon tension on the front side as well as ribbon running. While, the ribbon sensor R ("SA,
Ribbon Sensor" mounted on the rear side) is used to detect the ribbon tension on the rear side
as well as the ribbon end. These sensors are photointerrupters.
U1A
CPU
RIBSENS_A1
PCM0
34
U2B
RIBSENS_A2
PCM2
6
32
RIBSENS_B1
PCM3
31
U2D
RIBSENS_B2
PCM5
11
29
Ribbon sensor F:
The ribbon sensor F is used to keep the ribbon tension on the front side constant. When
printing starts, ribbon is fed and then the front side ribbon slacks. Then, the claws of the "SA,
Ribbon Tension Shaft F" come off the photointerrupters on the "SA, Ribbon Sensor" and the
photointerrupters turn ON. Thus, pin 34/32 (RIBSENS_A1/A2) of U1A (CPU) goes "High" level.
In this case, U1A (CPU) increases the revolution speed of "SA Ribbon Motor F" to take up the
slack of ribbon. As a result, ribbon tightens and the claws are inserted into respective
photointerrupters. Thus, pin 34/32 (RIBSENS_A1/A2) of U1A (CPU) goes "Low" level. Then,
U1A (CPU) slows down the revolution speed of "SA Ribbon Motor F". During printing, this cycle
is repeated and constant ribbon tension is maintained.
If ribbon is not correctly fed during printing, the ON/OFF state of the photointerrupters on the
"SA, Ribbon Sensor" becomes improper. Thus, the CPU can detect an abnormal ribbon feed.
Ribbon sensor R:
The ribbon sensor R is used to keep the ribbon tension on the rear side constant. When
printing starts, ribbon is fed and the rear side ribbon tightens. Then, the claws of the "SA,
Ribbon Tension Shaft R" are inserted into respective photointerrupters on the "SA, Ribbon
Sensor" and the photointerrupters turn OFF. Thus, pin 31/29 (RIBSENS_B1/B2) of U1A (CPU)
goes "Low" level. In this case, U1A (CPU) increases the revolution speed of "SA Ribbon Motor
R" to supply ribbon faster. As a result, ribbon slacks and the claw comes off the
photointerrupter. Thus, pin 31/29 (RIBSENS_B1/B2) of U1A (CPU) goes "High" level. Then,
U1A (CPU) slows down the revolution speed of the "SA Ribbon Motor R". During printing, this
cycle is repeated and constant ribbon tension is maintained.
When ribbon runs out, the ON/OFF state of the photointerrupters on the "SA, Ribbon Sensor"
becomes unchangeable. Thus, the CPU can detect the ribbon end.
CL-S6621
U21C
U2A
5
2
6
3
U21D
5
9
U2C
8
9
11
8
10
U21F
12
U21E
12
13
+3.3V
J102
J19
1
1
RA20
13
13
SENS_A1
14
14
SENS_A2
15
15
SENS_B1
16
16
SENS_B2
18-20
18-20
[SA, Ribbon PCB]
[SA, Main PCB]
2-26
Front (Take-up side)
PT501
J104
PS501
+3.3V
Ribbon Sensor1
1
1
+3.3V
2
2
3
3
4
4
R501
(SA, Ribbon Sensor)
Rear (Supply side)
J105
+3.3V
PT501
1
1
2
2
(Same as above circuit)
3
3
4
4
(SA, Ribbon Sensor)
PS502
Ribbon Sensor2
R502
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