Carriage Mechanism; Carriage Motor (Cr Motor) - Epson PH890 Service Manual

EPSON Stylus Photo 890/1290

2.1.2 Carriage Mechanism

The carriage mechanism of the Stylus Photo 890/1290 is composed of the carriage
motor (CR motor), carriage guide shaft, platen gap adjustment/parallelism adjustment
mechanism, carriage lock mechanism, and so on.

2.1.2.1 Carriage Motor (CR Motor)

The carriage mechanism of this printer is mostly the same as for other ink jet printers'
except it uses a DC motor as power source. See the table below for the carriage motor
specifications.
Table 2-3. Carriage Motor Specifications
Items
Type DC Motor with brush
Drive Voltage +42 V +/- 5% (Applied to the driver)
Coil resistance 29.2 ohms +/- 25%
Inductance 30.0 mH +/- 25%
Drive Method Constant Current Chopping
Driver IC LB1947
In previous ink jet printers, since a stepping motor is used as a CR motor, the CR motor
controls the carriage position under the open loop system. This printer, however,
controls carriage speed and position with the closed loop system enabled by a DC
motor and encoder. This system, also used in the Stylus COLOR 900, is applied to
maintain a constant print quality. The CR motor also produces the print timing signal
(PTS signal) used for an accurate ink ejection timing. (Refer to Section 2.2.2.3 for
further information on the CR motor control circuit.)
For printing, the CR motor moves the carriage unit in the printing area along the CR
guide shaft.
OPERATING PRINCIPLES
Table 2-4.
Specifications
Linear Encoder
Platen Surface
Figure 2-3. Carriage Mechanism (Top view)
Overview
Photo Coupler
CR Motor
Carriage Unit
Parallelism Adjustment
Adjust Lever
Bushing
Carriage Guide
Shaft
Eccentric Shaft
Revision B
Op03
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