Carriage Move Mechanism - Epson Perfection 3200 Photo Service Manual

EPSON Perfection 3200 Photo

2.1.2 Carriage Move Mechanism

Scanning image is performed in the main scan direction (=1 line) by the CCD
sensor and in the sub-scan direction (=several lines) combined with carriage
unit movement. (See Figure 2-3)
Line type, color CCD sensor can scan 1 line in main scan direction (parallel to
the carriage unit) by one time. When scanning next lines after the second line
in sub-scan direction, CR driving moves the carriage unit, which has CCD
sensor inside, and scan the other lines. The scanned data is sent to the control
board. The scanned data for "n" lines and "n-1" line are processed
consecutively.
1 pixel
Document
Main Scan
Direction
Sub-scan Direction by
CR Movement
Figure 2-3. Carriage Movement
Operating Principles
Second
Line
First Line
Scanner Head
(Carriage)
Engine Mechanism
Carriage Unit slides into sub-scan direction along with the guide rail. For this
sliding operation, the carriage motor drives the timing belt attached to the
carriage unit by conveying the driving force through the drive pulley and
reduction gear. Scanning start position is determined by CR HP sensor, which
is located on the control board. Since the stepping motor is used for CR motor,
carriage home position is controlled under the open loop system. (See Figure
2-4)
Rear
Carriage Unit
Front
Figure 2-4. Carriage Operation
Revision A
CR HP
Sensor Drive Pulley
Reduction
Gear
CR Motor
Timing Belt
Drive Pulley
18