Spacing Operation - Oki ML420 Maintenance Manual

2.2.2 Spacing Operation (See Figure 2-4.)
The spacing mechanism consists of a carriage shaft mounted in parallel with the platen, and
a carriage frame that moves along the shaft. It is driven by a DC motor mounted on the bottom
of the carriage frame. Items included in the spacing mechanism are as follows:
(a) DC motor with motor gear
(b) Carriage frame (stationary yoke and motor driver board included)
(c) Carriage shaft
(d) Space rack
(e) Sensor
(f) Encoder disk
(1)

Spacing operation

The carriage frame, on which the printhead and space motor are mounted, moves along
the carriage shaft in parallel with the platen. When the spacing motor rotates
counterclockwise, the driving force is transmitted to the motor gear. As the motor gear
rotates, the carriage moves from left to right.
Mechanically, it is designed in such a way that for every revolution of the DC motor, the
carriage frame moves 0.8 inch (20.32 mm).
At the same time the encoder disk rotates together with the motor and passes the sensor.
The position of the carriage frame can be determined by counting the interrupts detected
by the sensor.
In the same way, the rotation of the space motor can be recognized and controlled by
measuring the cycle of interrupts detected by the sensor.
Carriage frame
42113901TH01 Rev.3
Printhead
Carriage shaft
Motor gear
Guide rail
Figure 2-4
Oki Data CONFIDENTIAL
Space rack
Encoder disk
Encoder sensor
Slider
34 /