Description Of Components; Carriage Movement - Epson StylusPRO 7000 Service Manual

EPSON Stylus Pro 7000

2.2 Description of Components

2.2.1 Carriage Movement

To print on paper as wide as A1+ (24 inches), the printhead carriage must be
more stable and must travel further than the usual carriage. To make the
printheads more stable, EPSON added the CR Guide Rail to the SP 7000.
Like the EPSON Stylus Pro 9000, the SP 7000 does away with the carriage
guide shaft and relies on the printer frame for its stability. The carriage comes
into direct contact with the printer frame through the use of the carriage
bearings.
The CR motor uses a DC motor to drive the carriage and the Linear Encoder
sensor, in combination with the Step Ruler (plastic timing fence), determines
the lateral position of the carriage. As shown in Figure 2-7 below, the Linear
Encoder reads the shaded stripes to determine the position of the carriage as
well as the carriage speed, and this data is sent to the software servo.
The following sensors are used in combination with the CR Guide Rail
components:
"
HP Sensor
This optical sensor activates when the CR Guide Rail flag enters the
space between the light emitter and the light receiver. The flag is
located just above the home position, and the HP sensor sends an
"On" signal when the carriage is in the home position.
"
Linear Encoder sensor
This sensor is located on the back of the carriage, lower than the HP
sensor. For every shaded section the Linear Encoder passes over, the
LE sends a pulse to the CR motor as a PTS (Print Timing Signal). The
shaded sections have a distance equal to 180 dpi, and the software
controls use this spacing for reference purposes.
Operating Principles
Carriage
HP Sensor
Encoder
Figure 2-7. Carriage Mechanism & CR Guide Rail
Description of Components
CR Guide Rail flag (projected
No HP signal
Linear
(plastic strip w/ shaded stripes)
Revision A
area)
HP signal
Step Ruler
Carriage
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