Principles of Operation

Push Tractor Method

When the push tractor method is used with the rear entrance, the torque generated by the PF motor is transmitted to the push tractor gear through the PF motor pinion gear, paper advance reduction gear, and tractor reduction gear. When the PF motor pinion gear turns in the direction of the black arrow, the tractor gear rotates in the direction of the black arrow and thus feeds the paper into the printer. The paper is advanced by the platen and the paper tension roller, which are also driven by the PF motor through the gear train.

When the push tractor method is used with the front entrance, the torque generated by the PF motor is transmitted to the push tractor gear through the PF motor pinion gear, paper advance reduction gear, platen gear, and the gear train in the front part of the printer. When the PF motor pinion gear turns in the direction of the black arrow, the tractor gear rotates in the direction of the black arrow and thus feeds the paper into the printer. The paper is advanced by the paper drive roller and the platen, which are also driven by the PF motor through the gear train.

In the push tractor method, the release lever is set to one of the tractor positions to release the pressure between the paper advance roller and the platen. Figure 6-5 illustrates push tractor operation when paper is fed through the rear paper entrance. Figure 6-6 illustrates push tractor operation when paper is fed through the front paper entrance.

Paper (Continuous)

 

 

 

Paper Tension Roller

 

\

I

 

 

~ Push

Tractor

 

-.

 

 

\*.

 

 

l\ Tractor Gear

 

/

 

 

Tractor Reduction Gear

Paper Tension Roller Gear

1

, P F Motor Pinion Gear

 

 

P/aper Advance 6F Motor

Reduction Gear

Figure 6-5. Push Tractor Operation Using the Rear Paper Entrance

Epson FX-870/I 170

6-7