Epson DFX-8500 Service Manual page 65

OPERATING PRINCIPLES
‰Tractor select mechanism :
Figure 2-12 shows the operation of the tractor select mechanism. Clockwise rotation of the RF motor is
transmitted to the tractor select cam through the ribbon feed select gear and tractor select transmission
gear, and rotates the tractor select cam clockwise. The tractor select lever contacts the inside curve of the
cam due to the spring force; when the cam rotates, the tractor select lever moves horizontally along the
curve.
When the tractor select lever is set to the left, the tractor select gear engages the rear tractor assembly
train, and the PF motor rotates the rear tractor assembly. When the tractor select lever is set to the right,
the tractor select gear engages the front tractor assembly. The tractor Select sensor contacts the cam and
closes when it reaches the convex portion.
The ribbon jam sensor is used to detect ribbon jam condition and to count ribbon life.
Figure 2-12. Tractor Select Mechanism
2-11
Rev. B