Paper Feed Mechanism - Epson DFX-8500 Service Manual

PAPER FEED MECHANISM

Figures 2-7, 2-8, and 2-9 show the paper feed mechanism. After the printer loads the paper, it is fed by the
tension roller, platen roller, and front or rear tractor assembly.
The paper feed motor rotates the tension roller (Figure 2-7) and tractor select gear (Figures 2-8 and 2-9) and
moves either the front or rear tractor assembly. The paper feed transmission gear rotates the tractor select
gear, which can engage either tractor train. The tractor select mechanism alternates the engagement of the
rear tractor assembly gear train and front tractor assembly gear train. (See "Ribbon Feed and Tractor Select
Mechanisms" on page 2-10.)
The front and rear paper end sensors are on the tractor sprockets. When paper is loaded, the paper pushes
a leaf spring and blocks the photo interrupter. When no paper is loaded, the photo interrupter is not blocked.
The top paper end sensor is attached to the upper paper guide and is used with a reflection plate on the
paper bail assembly. When paper is loaded, the paper surface absorbs the beam; when there is no paper,
the beam is reflected. The pull tractor sensor monitors whether the pull tractor is installed.
Pull Tractor Sensor
Top Paper
End Sensor
Tension Roller
Figure 2-7. Tension Roller and Paper Feed Roller Operation
OPERATING PRINCIPLES
Paper Bail Lever
Paper Feed Timing Belt
Platen Gear
Tension Pulley
Tractor Select Gear
Paper Feed
Transmission Gear
Paper Feed Motor
Pinion Gear
2-7