Epson DFX-8500 service manual CR Motor Drive Circuit, CR Motor Specifications Description

OPERATING PRINCIPLES

2.3.4 CR Motor Drive Circuit

Figure 2-19 shows the internal circuit for the CR motor,Table 2-6 provides the CR motor specification, and Figure 2-20 shows a block diagram for the CR motor drive circuit.

An STK681-050 (IC1) bipolar driver IC drives the CR motor. It has built-in bipolar switching transistors and a current limiter. A comparator IC uPC393C (IC3) monitors the current in the CR motor driver IC (IC1). If the current exceeds the set value, it is fed back to the gate array (E05B36), and then the gate array outputs the signal for the current setting transistors (Q5, Q6, and Q7).

When the printer is turned on, CPU analog port AN2 measures the isolation resistance in the CR motor. If the isolation resistance is equal or less than 2.2 K ohms, the printer change the status to the carriage error.

If the printer cover is open during power on, the CR motor driver power is cut by the interlock switch.

The ENCA pulse that the carriage encoder outputs is input to general purpose port CRENCA of the gate array, and the ENCB pulse that the carriage encoder outputs is input to general purpose port CRENCB of the gate array. The gate array counts these pulses using the internal counter and determines the amount and direction of motor rotation.

Table 2-6. CR Motor Specifications

Specification	Description
Form	DC servo motor
Supply Voltage	37 VDC
Internal Coil	1.66 ohms (+ 10 %)
Resistance
Current	Accerelation / Deceraration:
Consumption*1)	4.6 A (AV.)
	Constant Speed:
	2.5 A (AV.)

*1): at Super draft printing, + 10 %

VP3 (+37 VDC)

Q1	Q3
	Motor
Q4	R1
	Q2

GP3 (GND)

									Figure 2-19. CR Motor Internal Circuit
									ENCA
				MAIN			DRV		ENCB
					VX	VX		VP3	Interlock SW
				Board			Board
E05B36 (IC1)							STK681-050(IC1)
		CRENCA		CRENCBCRBX	Q17,	Q35,	IN_B		Carriage Encoder Sensor
								VCC1
				CRAX	Q16,	Q34,	IN_A
								VCC1
				CRCX	Q18,	ZD2	IN_C
CRCLM				CRDX	Q19		IN_D	OUT1	CR A
	CRI0	CRI1	CRI2	CRCLK
							CLK		Motor
									Carriage
								OUT2
							GP	GP	CR B
							Vref	GP3
									Vx
							Q5,	AIN+	+5V
							Q6,	AIN-
							Q7
								A OUT	Vref
								uPC393C(IC3)
									ZD1
									4.3 V
					CRCLM
	CPU								GP3
TMP85C061					CRINS	Partical Pressure			D3
	(IC2)		AN2
						Circuit

Figure 2-20. CR Motor Drive Circuit Block Diagram

Rev. B 2-25