Epson DFX-8500 service manual Sensor Circuits, Sensor Circuit Block Diagram

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)

			CPU
		TMP95C061 (IC2)
XNMI	AN2	INT5	AN3	AN1	AN0
10	22	35	23	21	20

8	18	1	29	19	22
POFF (SD)	CR Motor Insulation	Cover Open	Paper Width	Head Fan Temperature	Printhead Temperature
CN10	CN14	CN3		CN1
		ENCA	148		3
						ENCA
								CN4
			149		4
		ENCB					CR Encoder
						ENCB
	PGENCA		28		35	PGENCA
					34
	PGENCB		25			PGENCB
	PG Home		18		36	PG Home
E05B36 (IC1)		TRSEL	19		28	Tractor Select
	PTRCT		20		29	Pull Tractor
		PJAM	21		30	Paper Jam
			22		31
		FPE				Front PE		CN14
		RPE	23		32	Rear PE
			24		33
		TPE				Top PE
					37
		RBJAM 29				Ribbon Jam

Figure 2-18. Sensor Circuit Block Diagram

2-22 Rev. B