Epson LQ-1170 Service Manual page 44

Pull Tractor Method
Pull tractor feeding is basically the same as push tractor feeding. In push tractor feeding, the tractor
(the paper advance mechanism) is before the paper entrance. It pushes the paper through the printer
mechanism. In pull tractor feeding, however, the tractor is after the paper entrance. Because it
the paper through the printer mechanism, it requires no paper tension unit. Figure 2-6 illustrates pull
tractor operation when you insert paper into the bottom paper entrance.
Push-Pull Tractor Method
The push-pull tractor method is a combination of the push tractor and pull tractor methods. In push-pull
tractor feeding, the printer uses two tractors, one in front of and one behind the paper entrance, to
advance the paper. They simultaneously push and pull the paper through the printer mechanism. Figure
2-7 illustrates push-pull tractor operation.
Paper (Continuous)
" ' t e n '---.4+
Figure 2-6. Pull Tractor Operation
Paper
(Continuous)
Pull Tractor
Platen Gear
Paper Feed Mo'tor ~
Pinion Gear
Figure 2-7. Push-Pull Tractor Operation
Pull Tracter
Paper Feed Motor
Pinion Gear
Paper Feed Reduction
Gear
Push Tractor
Tractor Gear
Paper Tension Roller
Transmission Gear
Tractor Reduction Gear
Paper Feed
Motor
/ I "
2-5
Tractor Gear
Paper Tension Roller
Motor
I
REV.-A