Tektronix PHASER 380, Service Manual

Page: 113 / 346

Service Manual 5-11
Theory of Operation
5
X-axis drive system
The X-axis drive system controls the lateral, left-to-right, motion of the printhead
for imaging. X-axis movement of the printhead is accomplished by a
motor-driven pulley system. A stepper motor, driving through a two-stage
reduction gear, turns a capstan. The capstan, in turn, drives a stiff, yet flexible,
split-metal band which attaches to each end of a frame supporting the printhead.
As the capstan turns, it moves the printhead along a pair of X-axis rails parallel
to the axis of the drum. Two steps of the motor translate the printhead a distance
equal to one 300 dpi pixel.
An x-axis home sensor on the left side of the printer indicates when the
printhead has been returned to its home position.
Figure 5-6 X-axis printhead movement during printing
Printhead
X-axis drive motor
Compound idler
Home
sensor
Rear
guide rail
X-axis shaft
Capstan
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