EPSON Stylus Scan 2500 Revision A
Operating Principles Scanner Principles 51
2.3.2 Carriage Operation
Scanning is performed in the main scan direction (=1 line) by the CCD sensor
and in the sub-scan direction (=several lines) by the carriage movement. (See
Figure 2-20.)
The 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.
Figure 2-20. Carriage Movement
The Carriage Unit slides in the sub-scan direction along 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 driven 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 head position is controlled under the open loop system.