Oki IP-6620 Maintenance Manual page 528

OKI Data Infotech Corporation CONFIDENTIAL
Chapter 8 Operation Mechanism
(6) T-fence (linear scale) and linear encoder
T-fence and linear encoder are the sensor (photo interrupter) attached on the top of the carriage.
Since the absolute position of the carriage must always be recognized for printing, T-fence (linear
scale) covers the range of the carriage movement. The linear scale is read by the linear encoder
sensor, and the linear encoder sensor generates a 2-phase clock with different phases. The
engine controller firmware always recognizes the carriage's absolute position by counting the
pulses from this sensor. In addition, the signals detected by the linear encoder are also used for
checking the carriage motor position. Ink is ejected from the print head nozzles with matching the
output signals from this sensor.
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