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REV.-A
2.4.2 Operation of the Print Mechanism
The print mechanism is constituted of the following:
• Carriage mechanism (carriage, carriage motor, and carriage home position sensor)
• Printhead
2.4.2.1 Carriage Mechanism
A timing belt is fixed to the base of the carriage, and is driven by the carriage motor by means of a
pulley. The operation of the timing belt causes the carriage (together with the printhead) to move left
and right along the axle.
Carriage guide shaft A, the cross-sectional shape of which is elliptical, forms the mechanism that allows
the platen gap to be adjusted with the lever.
Encoders A and B are located within the axle of the carriage motor's rotor, and guide the generation
of the signals that control the carriage movement. Both encoders A and B output 120 signal pulses
for each revolution of the carriage motor.
The encoder A phase (advance signal) and the encoder (delayed signal) have a 90 deg. phase difference,
and the revolution direction of the carriage motor can be determined by a phase comparison. The
encoder A phase detects carriage motor revolutions and control the speed; in addition, the A phase
signals standard head drive (printing) timing.
The carriage home position sensor generates the carriage home position signal, based on which the
print starting location is calculated. The sensor is comprised of a photosensor and the carriage detection
board; when the board blocks the photosensor light, a HIGH signal is output. The interface ofthe carriage
home position sensor and the control circuit is detailed in Section 2-40. (Identical to TE/PE sensors)
Figure 2-6 shows the carriage mechanism.
Carriage Motor Specifications
Type:
Encoder-attached DC motor (Bipolar, 7 slots)
Drive voltages:
24VDC± 10% (motor section)
5 VDC±5% (encoder section)
Maximum current: 3.0A (based on current limiting circuit)
Motor Section Specifications
Rated voltage:
Rated current:
Rated torque:
Rated revolution speed:
No-load revolution speed:
No load current:
Starting current:
DC resistance:
Insulation resistance:
24VDC
typ.800mA
200gf-cm
typ. 6400 rpm
typ. 7400 rpm
typ. 150mA
typ. 5A
3.2 ±7% (at 20°C)
min. 10M (at 500V)
2-42
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