Carriage Mechanism - Epson 680Pro - LQ B/W Dot-matrix Printer Service Manual

EPSON Stylus COLOR 680/777/77i

2.1.3 Carriage Mechanism

The carriage mechanism consists of Carriage motor (CR motor), Carriage unit
(including printhead), CR timing belt, CR guide shaft, CR guide frame, CR home
detector (HP/PE sensor) etc. The carriage mechanism moves the carriage back and
forth according to the drive from the carriage motor. The following stepping motor is
mounted to drive CR mechanism. (See the table below.)
Table 2-1. Carriage Motor Specification
Items Specifications
Type 4-Phase/ 200-Pole HB Stepping motor
Drive Voltage +42 V +/ - 5% (DRV IC voltage)
Coil Resistance 7.8 +/ - 10% (per phase at 25 degree)
Inductance 14 mH +/ - 20%(1KH 1VmA)
Drive Method Bi-Polar drive
Driver IC LB11847
The drive from CR motor is transferred to the CR unit via CR timing belt. And the CR
home position is detected with the HP/PE sensor. This sensor is available as CR HP
detector only in the HP (home position) detection sequence & pump operation
sequence. (not available in the paper feeding sequence for the CR HP detector because
it is used for only PE sensor during the paper feeding sequence.) Moreover, unlike the
previous products, this printer dose not have the PG adjustment mechanism (1.7mm).
CR unit
Figure 2-4. Carriage Mechanism (Top view)
Operating Principles
HP/PE Sensor
CR Motor
CR Timing belt
CR Guide shaft
CR home position is detected with the HP/PE/IC sensor and the detection plate molded
in the CR unit as following figure. When the CR home position is detected with this
sensor, HIGH signal is output to the CPU.
HP detection Lever
CR HP detection plate
Figure 2-5. CR home position
Overview
Revision B
Right side view
CR HP detection plate
HP/IC detection Lever
High signal
Low signal
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