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Figure 2-47 shows the timing for discharge/charge pulse.
Figure 247. Timing for Discharge/Charge
(2)
Voltage Supply Circuit
Pulse
The viscosity of ink is subject to change due to the temperature. If the viscosity is too high, ink injection
becomes difficult. To eliminate this difficulty, the head drive voltage (Vh: the +35
voltage boosted
to 83 -123.7
in this circuit) is controlled based on the ink temperature detected by the thermistor.
That is, the temperature is fed back to the voltage supply circuit and controlled by
Since each
produced shows slightly different characteristics, this difference must be
neutralized by adjusting the head drive voltage. For this purpose, several
diodes (used for
detecting output voltage) and a
jumper are provided. When the
or the MAIN board is
replaced, adjust the
jumper to connect the
diodes in proper arrangement.
For safety, this circuit is
disconnected when a case open condition is detected.
2.3.7 Pump Motor Drive Circuit
Figure 2-48 shows the block diagram of the pump motor drive circuit.
A DC motor is used to drive the pump. The drive circuit is controlled by the collector-follower
bridge -
16).
The rotational direction of the motor is controlled through the ports on
If PMCW signal is
transmitted from
the motor rotates
If
signal is transmitted from PC 1, the motor rotates
Ccw.
CPU
Pump
MOTOR
I
Bus
PM+
P c l
NPN2B
I
I
I
Figure 248.
Block Diagram of Pump Motor Drive Circuit
2-36
Summary of Contents for SQ-1170
Page 1: ...EPSON TERMINAL PRINTER SQ 870 1170 4001225 REV A ...
Page 5: ... REVISION SHEET REVISON DATE ISSUED CHANGE DOCUMENT A Feb 21 1992 1st issue L e v ...
Page 143: ...REV A T hlta RR Ransir nf the Main Board Cont w w 5 16 ...
Page 149: ...c ...
Page 153: ...REV A Figure 6 2 Lubrication Points 1 6 3 ...
Page 154: ...REV A L Figure 6 3 Lubrication Points 2 6 4 ...
Page 162: ...53 co Re tifier Figure A 4 C076 PSB Board Circuit A 9 ...
Page 163: ...4 4 4 IJ 1 I 4 b 4 b 4 s v 5 s w 0 v Figure A 5 C076 PSB Board Circuit A 10 ...
Page 165: ...1 1 1 1 N a I I r c1 L k Figure A 7 C076 PSE Boerd Circuit Diagram A 1 2 J ...
Page 166: ... 11 I 1 I L I 1 Figure A 8 Control Panel Board Circuit Diagram A 1 3 ...
Page 176: ...EPSON Printed in Japan 92 02 7 G ...