Carriage Mechanism - Epson SQ-1170 Service Manual

REV.-A

2.1.2 Carriage Mechanism

The timing belt attached to the base of the carriage is driven by the carriage motor and the pulley. This
makes the carriage (printhead) move along the guide shafts.
A scale made of polyester (DETECTION, PLATE, PTS) is provided along the motion range of the carriage.
The optical linear encoders mounted on the carriage scan this scale and output one pulse of signal each
time the carriage moves 1/1 20 inch. The signal consists of Phase-A and Phase-B, which are 90 degrees
different from each other. Therefore, the controller can recognize the moving direction of the carriage
by detecting this difference. The controller can also recognize the carriage speed from the signals sent
from the encoders.These signals are also used to adjust print timing.
This printer is not provided with a home position sensor. Instead, the carriage is designed to hit the
left stroke end each time the printer is initialized. At this time, the controller resets the carriage position
counter to "O" and then counts up/down pulse signals sent from the encoder to determine the carriage
position.
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Figure 2-7. Carriage Mechanism
2-4
Carriage
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SHAFT, CR, GUIDE, MAIN
/Timing Belt
Carriage
Motor