Carriage Mechanism; Carriage Motor (Cr Motor) - Epson Stylus PHOTO 1270 Service Manual

EPSON Stylus Photo 870/1270

2.1.2 Carriage Mechanism

The carriage mechanism of the Stylus Photo 870/1270 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 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 2-2. 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 30.8 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
Specifications
Overview
Photo Coupler
Carriage Unit
Linear Encoder
Adjust Lever
Platen Surface
Eccentric Shaft
Figure 2-3. Carriage Mechanism (Top view)
Revision B
CR Motor
Parallelism Adjustment
Bushing
Carriage Guide
Shaft
Op03
35