Epson FX 1170 - B/W Dot-matrix Printer Service Manual page 53

(4) push-pull Tractor Method
The push-pull tractor method is a combination of the push and pull tractor methods. Two tractors are used
to advance the paper: one at the front paper entrance and the other at the rear paper entrance. They operate
simultaneously to push and pull the paper through the printer mechanism. Figure 2-8 illustrates push-pull
tractor operation when the paper is fed through the rear paper entrance. Figure 2-9 illustrates push-pull tractor
operation when the paper is fed through the front entrance.
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Figure 2-8. Push-Pull Tractor Operation Using the Rear Paper Entrance
Paper (Continuous)
. . . . . . .
./\
/
,.
/ .
Pull Tractor
\
' .
/
1
/
Paper Advance
Reduction Gear
2-1o
Push Tractor
Tractor Reduction Gear
PF Motor Pinion Gear
PF
: .'