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REV.-A
Control Circuit
The control circuit consists of hybrid
148 (2 C). This
is divided into four blocks.
1. HF Motor ON/OFF Circuit
This circuit controls the ON/OFF switching of the HF motor using two inputs
signal and HF motor
thermistor resistance). The sub CPU sets the
signal LOW when the thermistor in the printhead
detects a temperature of 40”C or higher. While the HF motor is on, the sub CPU monitors the temperature
of the HF motor using a thermistor in the HF motor to prevent the motor coils from burning if the motor
stops due to external noise (Refer to Table 2-5 1.).
Table 2-51.
Input Signal and HF Motor Status
TH Terminal Voltage [V]
HF Motor Status
Note
H
—
OFF
4.22
ON
Normal
L
4.22
HF motor abnormal heat generation occurs.
4.15
OFF
ON
HF motor abnormal heat generation ends.
NOTE: Even when the
HF motor is on, the motor will stop five seconds after the last print signal is
received.
2.
Integration Circuit
When the output from the HF motor ON/OFF circuit changes from HIGH to LOW, it is integrated by this
circuit, and output to the block in the second stage. Acceleration control is performed using this
integrated waveform.
3. Unstable Oscillation Circuit
This circuit generates the reference clock to execute phase switching for the HF motor. R43 is an
oscillation frequency selection resistor. The frequency starts rising gradually at the leading edge of the
integrated signal from the previous stage and
at the set value
1600 Hz).
4. Phase Pulse Generation Circuit
This circuit generates the phase switching pulse for the 2-phase stepper motor. The phase switching
pulse is synchronized
with the clock
pulse output from the previous stage.
Drive Circuit
The drive circuit consists
an HF
coil drive transistor and
surge voltage absorption circuit that
absorbs the surge voltage output from the motor coil when the HF motor coil drive transistor changes
from on to off. D4 and
are flywheel diodes, and ZD5 is a surge voltage consumption Zener diode.
2-81
Summary of Contents for LQ-2550
Page 1: ...L Q 2 5 5 0 TECHNICAL MANUAL EPSON ...
Page 240: ...REV A P r cl Figure 6 3 LQ 2550 Lubrication and Adhesive Application Points Diagram 2 6 3 ...
Page 241: ...REV A 7 i_ Figure 6 4 LQ 2550 Lubrication and Adhesive Application Points Diagram 3 6 4 ...
Page 252: ...REV A I 1 I 7 v m o m x b Figure A 6 PPD781OHG Block Diagram A 7 ...
Page 297: ...REV A 1 L I Irl N I i t 1 I I x Figure A 50 ROPSE Board Circuit Diagram A 52 ...