Carriage Mechanism - Epson Stylus COLOR 880 Service Manual

EPSON Stylus COLOR 880

2.1.1.3 Carriage Mechanism

The carriage mechanism for the Stylus COLOR 880 is mostly the same as for
other ink jet printers except it is driven by a DC motor. See the table below for
the carriage motor specifications.
Table 2-2. Carriage Motor Specification
Items
Type DC Motor with brush
Drive Voltage +42 V +/- 5%(DRV IC voltage)
Internal Resistance 29.2 ohms +/- 25%
Inductance 30.8 mH +/- 25%
Drive Method Constant Current Chopping
Driver IC LB1947
Unlike a stepping motor, the DC motor that drives the carriage can not detect
the current carriage position by referring to the pulses given. Therefore, a linear
scale is attached along the carriage operation range to enable the printer to
mechanically detect the carriage position. The linear scale is also used to
produce the print timing signal (PTS signal), to which the printer refers to for a
correct ink ejection timing.
For detailed information on the CR motor control circuit, see Section 2.2.
Carriage Motor
PF Roller Timing Belt Carriage Unit
Eject Roller
Paper Guide (Front)
PF Motor
Figure 2-5. Carriage Mechanism (Top view)
Operating Principles
Specifications
Front Side Rear Side
Parallelism
Adjust Lever
Fixing
Bushing
Carriage
Guide Shaft
CR Lock Lever
The printhead, a core of the printing mechanism, is stored in the carriage unit.
When the adjustment lever is moved up and down, this printhead is maintained
tilt in a flexible and adjustable structure by the tilt adjustment mechanism.
Also, the parallelism adjustment levers, mounted on the left and right sides of
the carriage guide shaft, are used to set the carriage guide shaft parallel to the
platen when the shaft has been installed to the printer mechanism. After this
adjustment is completed, moving the PG adjustment lever sets the distance
between the platen surface and the printhead surface to one of two
possibilities: 1.14 mm or 1.84 mm. Moving the PG lever, you can rotate the
shafts of the carriage guide shaft which itself is decentralized to change the
distance. This is the mechanism that the user can use to adjust the appropriate
PG value according to the printing result or any other environmental conditions
such as thick paper.
Overview
Revision A
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