Oki IP-6620 Maintenance Manual page 527

8.2 Carriage System
The carriage system comprises the following units (1) to (6):
(1) Carriage motor
Carriage motor is a DC motor installed within the right cover of the printer. This motor, used for
moving the carriage back and forth horizontally, supports speed control from the minimum to the
maximum speed.
The motor position is detected by a linear encoder installed on the printer's Y-rail (ink ejection
timing is controlled by the linear encoder signals).
(2) Carriage
Carriage is the printing unit installed on the printer's Y rail via the bearings and is driven by the
carriage motor via the steel belt. The printer is equipped with a carriage board, six (or seven)
print heads, edge sensors, a linear encoder, a head cooling fans, ionizers, and a board for
automatic print adjustment.
(3) Carriage board
Carriage board is the board mounted on the carriage, and executes the following functions:
- Assigns the print data transmitted from the engine control board to each print head.
- Performs output of the thermistor installed on the carriage (head temperature) and detection
of the media edges, and at the same time, outputs the signal of the linear encoder to the
engine control board.
- Controls the head discharge timing based on the linear encoder signals.
(4) Edge sensor
Edge sensors are installed on the side of the carriage, and detects the presence of media on the
platen and the media edges on both sides. The CPU of the engine control board controls the
overall printing by using data as the media standard for print start position, detection of skew, etc.
The signal from the edge sensor is transmitted from the carriage board to the engine control
board and detected by the CPU.
(5) Home position sensor
Home position sensor is a photo sensor installed on the carriage. The engine controller cannot
recognize the carriage position immediately after turning on the printer, so the carriage is first
moved to the position where the home position sensor turns on (home position), detected as the
initial position of the carriage.
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OKI Data Infotech Corporation CONFIDENTIAL
Chapter 8 Operation Mechanism