Epson DFX-8500 Service Manual page 77

Each sensor is described below.
1. Front and rear paper end sensors
‰Detection form:
‰Output form:
‰Logical:
2. Top paper end sensor (to detect the TOF position)
‰Detection form:
‰Output form:
‰Logical:
3. Paper jam sensor
‰Detection form:
‰Output form:
‰Logical:

‰Supplement:
4. Tractor select sensor
‰Detection form:
‰Logical :
5. Pull tractor sensor
‰Detection form:
‰Logical :
6. Carriage encoder sensor
‰Detection form:
‰Transaction:
7. Platen Gap encoder sensor
‰Detection form:
‰Output form:
‰PG ability:
‰Available range:
8. Platen Gap home position sensor
‰Detection form:
‰Logical::
9. Ribbon jam sensor
‰Detection form:
‰Function:
:
10. Cover open sensor
‰Detection form:
‰Logical::
11. Printhead temperature sensor (uses a thermistor)
The thermistor is included on the printhead.
12. Head fan temperature sensor (uses a thermistor)
The thermostor is included on the head fan.
Rev. B
Photo interrupter
Open collector (pulled up to 10 K ohms resistor)
Paper present: LOW
Paper out: HIGH
Photo reflector
Open collector
Paper present: LOW
Paper out: HIGH
Magnetic transistor
Rectangle wave (1 channel, TTL level)
Paper feed: Level changes continuously.
Paper jam: Level remains the same.
The magnetic transistor is attached to the tension roller on the paper tension unit.
Micro mechanical switch
Front tractor: LOW (closed)
Rear tractor: HIGH (open)
Micro mechanical switch
Pull tractor installed: LOW (closed)
Pull tractor not installed: HIGH (open)
Photo reflector
Rectangle wave, A and B phases respectively.
Photo interrupter
Rectangle wave, 2 channel
T = 0.015 mm / pulse
0 < T < 0.7 mm
Micro mechanical switch
Home: LOW (closed)
Out of home: HIGH (open)
Photo interrupter
The main board monitors signal change during ribbon feed.
Micro mechanical switch
Cover closed: LOW
Cover open: HIGH
OPERATING PRINCIPLES
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