Sensor Circuits - Epson DFX-8500 Service Manual

DFX-8500

2.3.3 Sensor Circuits

Figure 2-18 shows the sensor circuits in block diagram form. The printer is equipped with the following
sensors:
1. Front and rear PE sensors (use a photo interrupter)
2. Top PE sensor (to detect the TOF position, uses a photo interrupter)
3. Paper jam sensor (uses a magnetic transistor)
4. Tractor select sensor (uses a micro mechanical switch)
5. Pull tractor sensor (uses a micro mechanical switch)
6. CR encoder sensor (uses a photo interrupter)
7. PG encoder sensor (uses a photo interrupter)
8. PG home sensor (uses a micro mechanical switch)
9. Ribbon jam sensor (uses a photo interrupter)
10. Cover open sensor (uses a micro mechanical switch)
11. Printhead temperature sensor (uses a thermistor)
12. Head fan temperature sensor (uses a thermistor)
13. Paper width sensor (uses a photo reflector)
14. CR motor isolation resistance sensor (monitored by the analog port of the CPU)
15. PSB/PSE board power off sensor (signal interface)
Figure 2-18. Sensor Circuit Block Diagram
2-22
Rev. B