Epson DFX-8500 - Impact Printer, Service Manual

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DFX-8500
Rev. B
2-32
2.3.8 Plunger Drive Circuit
Figure 2-26 shows a block diagram of the plunger drive circuit, Table 2-12 provides the plunger specification,
and Table 2-13 provides the plunger switching pattern.
The plunger is driven using three switching patterns. Gate array E05B26 ports PLP and PLN output the
plunger coil drive signals. When the PNP port of the gate array turns on switching transistors Q30 and Q31
are turned on and the supply voltage (VP3) flows into the plunger coil. When switching transistor Q30 is
turned off, Q31 is turned off and the hold voltage (+5 V) flows into the plunger coil via Q32, using the port
PLN of the E05B36.
Table 2-12. Plunger Specifications
Specification Description
Form DC solenoid
Supply Voltage 37 VDC (applied to the drive circuit)
Internal Coil Resistance 9 ohms + 5 % at 25
o
C
Current Consumption Driving: 3.7 A (MAX.)
Holding: 0.4 A
Table 2-13. Plunger Switching Pattern
Suspension Roller Status Q30 and Q31 Q32
Closed Off Off
Closed -> Opened On Off
Closed with holding voltage Off On
Q30
E05B36
(IC1)
PLP
P
LN
E
C B
NPN
Q31
PNP
B
C
P
lu
ng
er
C
oil
GP3
Q32
E
B
C
VP 3
F3
Figure 2-26. Plunger Drive Circuit Block Diagram