Paper Feed Mechanism

Cut sheet paper is advanced by friction feed. Continuous form paper is advanced using a tractor feed mechanism.

There are three ways to advance the paper with tractor feed: using the push tractor, using the pull tractor, using the push and pull tractors together. Any one of these three tractor configurations can feed paper through the printer. In normal operation, the printer is set up with one tractor, which functions as either a push tractor or pull tractor, depending on where it is attached to the printer body. To use the push-pull tractor feed method, an optional tractor must be attached in addition.

There are also four ways to insert paper into the printer. Different paper paths are used for different types of paper. Table 2-1 lists which paper paths can be used for each of the various paper advance methods.

_Table 2-1, Paper Advance Methods and Paper Paths_

Paper Insertion (Paper Paths)

Paper Advance Method

Rear Entrance

Front Entrance

Bottom Entrance

Top Entrance

Friction Feed

No

OK

No

OK

Push Tractor

OK

No

No

No

Pull Tractor

No

OK

OK

No

Push-pull Tractor Feed

OK

No

No

No

2.1.3.1 Paper Advance Mechanisms

This section describes how the friction feed and tractor feed mechanisms work to advance the paper in the printer.

Friction Feed Method

The paper is held between the platen and paper advance' roller, and between the paper eject roller and paper eject unit cover. The paper-feed pinion gear, turning in the direction of the black arrow, drives the COMBINATION GEAR, 8.5, 30. The COMBINATION GEAR, 8.5, 30 turns the SPUR GEAR, 34, paper-feed rollers, and top ROLLER ASSY., PAPER EJECT. The paper then advances in the direction of the white arrow.

The paper advance roller spring holds the paper against the platen. Setting the LEVER, G, ADJUST to the tractor feed position releases this pressure and frees the paper. Figure 2-4 illustrates friction feed when paper is inserted through the top entrance.

Figure Entrance Detector Mechanism

MOTOR, PF

Figure 2-4. Top Path Friction Feed 2-3

MOTOR, PF

Figure 2-4. Top Path Friction Feed 2-3

Push Tractor Method

When the push tractor is selected, the SPUR GEAR, 16 engages the SPUR GEAR, 17 (Tractor gear) on the TRACTOR ASSY. COMBINATION GEAR, 8.5, 30 is driven by the paper-feed gear, which in turn is driven by the paper-feed motor pinion gear. The paper-feed pinion gear, when turning in the direction of the black arrow, results in pushing the paper through the mechanism.

I During tractor feeding, the LEVER, G, ADJUST is set to the tractor position to disengage the friction drive. This releases the pressure between the paper advance roller and the platen. Figure 2-5 illustrates push tractor operation.

Paper (Continuous)

Paper (Continuous)

Manual Tecnico Dfx 8500
MOTOR, PF Figure 2-5. Push Tractor Operation

Pull Tractor Method

Using pull tractor feed to advance the paper is basically the same as using push tractor feed. In push tractor feed, the TRACTOR ASSY, (paper advance mechanism) is before the paper entrance. It pushes the paper through the PRINTER MECHANISM.Pull tractor feed,however, has the opposite arrangement, with the tractor situated after the paper entrance. Since Pulls the PaPer through the PRINTER MECHANISM, it requires no paper tension unit. Figure 2-6 illustrates pull tractor operation tractor when paper is inserted through the bottom path.

Paper (Continuous)

TRACTOR ASSY.

PLATEN '

SPUR GEAR, 16

SPUR GEAR, 40

TRACTOR ASSY.

PLATEN '

SPUR GEAR, 16

SPUR GEAR, 40

Paper Counting Mechanism

SPUR GEAR, 17

SPUR GEAR, 17

Gear

COMBINATION GEAR, 8.5, 30 Figure 2-6. Pull Tractor Operation

Push-Pull Tractor Method

This is a combination of the push tractor and pull tractor methods. TWO tractors are used, one in f of and one behind the paper entrance, to advance the paper. They act simultaneously to push and the paper through the PRINTER MECHANISM. Figure 2-7 illustrates push-pull tractor operation.

Paper (Continuous) SPUR GEAR, 16

'rent pull

TRACTOR ASSY. (Push)

PLATEN

SPUR GEAR, 17

TRACTOR ASSY. (Push)

PLATEN

SPUR GEAR, 17

Paper Feed Motor Pinion Gear

TRACTOR ASSY. (Pull)

SPUR GE'AR, 17

Paper Feed Motor Pinion Gear

TRACTOR ASSY. (Pull)

SPUR GE'AR, 17

SPUR GEAR, 34 COMBINATION GEAR, 8.5, 30 MOTOR, PF

Figure 2-7. Push-Pull Tractor Operation

The LEVER, RELEASE switches between friction feed and tractor feed. Setting the LEVER, RELEASE to the friction feed position presses the paper advance roller against the PLATEN. Setting the release lever to the tractor feed position releases this pressure, so that the paper advance roller separates from the PLATEN. The DETECTOR ASSY., RELEASE senses the current position of the LEVER, RELEASE.

Figure 2-8. LEVER, RELEASE Movement 2.1.3.2 Paper Insertion Entrances

This section describes the different ways to feed paper into the printer. Top entrance paper insertion

When you feed paper into the printer through the top entrance, the method to advance the paper is friction feed.

Figure 2-8. LEVER, RELEASE Movement 2.1.3.2 Paper Insertion Entrances

This section describes the different ways to feed paper into the printer. Top entrance paper insertion

When you feed paper into the printer through the top entrance, the method to advance the paper is friction feed.

There are two paper-out detectors: the front paper-out detector is in front of the PRINTER MECHANISM and the rear paper-out detector is behind the PRINTER MECHANISM. When paper is inserted through the top entrance, the rear detector senses when the paper runs out.

Paper (Cut Sheet)

Paper (Cut Sheet)

Friction Feeder Mechanism
Figure 2-9. Paper Path for Top Entrance Friction Feed

Rear entrance paper insertion

When you feed paper into the printer through the rear entrance, the method to advance the paper can be: the push tractor, or the push-pull tractor. The rear paper-out detector senses when the paper has run out.

Paper (Continuous)

ROLLER ASSY., PAPER EJECT PAPER GUIDE

Paper (Continuous)

TRACTOR ASSY.

DETECTOR ASSY., PE, REAR

TRACTOR ASSY.

DETECTOR ASSY., PE, REAR

Paper Feed Roller

Figure 2-10. Paper Path for Rear Entrance Push Tractor Feed

Paper (Continuous)

Printhead

Paper (Continuous)

Printhead

Paper Feeding Mechanism

TRACTOR ASSY.

DETECTOR ASSY., PE, REAR

Paper Feed Roller

Figure 2-11. Paper Path for Rear Entrance Push-Pull Tractor Feed

TRACTOR ASSY.

DETECTOR ASSY., PE, REAR

Paper Feed Roller

Figure 2-11. Paper Path for Rear Entrance Push-Pull Tractor Feed

Bottom entrance paper insertion

When you feed paper into the printer through the bottom entrance, the pull tractor advances the paper. The front paper-out detector senses when the paper runs out.

Paper (Continuous)

Paper (Continuous)

/ From Bottom Insertion

Figure 2-12. Paper Path for Bottom Entrance Pull Tractor Feed

/ From Bottom Insertion

Figure 2-12. Paper Path for Bottom Entrance Pull Tractor Feed

Front entrance paper insertion

When you feed paper into the printer through the front entrance, the paper can be advanced either with friction feed or the pull tractor. The front paper-out detector senses when the paper runs out.

Printhead PaPer (Cut sheet)

ROLLER ASSY., PAPER EJECT

PF Drive Roller

DETECTOR ASSY., PE, FRONT

Printhead PaPer (Cut sheet)

PF Drive Roller

DETECTOR ASSY., PE, FRONT

ROLLER ASSY., PAPER EJECT

Figure 2-13. Paper Path for Front Entrance Friction Feed

Paper Feed Roller From Front Insertion

Figure 2-13. Paper Path for Front Entrance Friction Feed

Paper (Continuous) Printhead

DETECTOR ASSY., PE, FRONT

From Front Insertion

TRACTOR ASSY.

TRACTOR ASSY.

DETECTOR ASSY., PE, FRONT

From Front Insertion

Figure 2-14. Paper Path for Front Entrance Pull Tractor Feed

Figure 2-14. Paper Path for Front Entrance Pull Tractor Feed

2.1.4 Ribbon Advance Mechanism

The ribbon drive gear advances the ribbon through a gear linkage. This arrangement of gears makes the ribbon drive gear always rotate in a counterclockwise direction, regardless of the direction the carriage is moving.

Table 2-2. Ribbon Advance Gear Linkage

Direction of Carriage Movement

Gear Linkage

Left to right (arrow ^ )

PULLEY, DRIVEN ^ Ribbon transmission gear # COMBINATION GEAR (1) • COMBINATION GEAR (3) COMBINATION GEAR (4) • RATCHET, RD

Right to left (arrow 0 )

PULLEY, DRIVEN 0 Ribbon transmission gear 0 COMBINATION GEAR (1)0 COMBINATION GEAR (2) 0 RATCHET, RD

The ink ribbon within the cartridge case is an endless ribbon that is held against the ribbon advance roller by the pressure of the ribbon grip roller. The ribbon advance roller, linked to the ribbon drive gear, winds the ink ribbon.

The ribbon brake spring, attached to the exit slot of the cartridge case, prevents slack in the ribbon and keeps the ribbon tension correct, The ribbon mask keeps the paper clean by preventing the ribbon from brushing against the paper.

Ribbon Feed Roller

Ribbon Pressure Roller

Ribb»n Transmission Gear SPUR GEAR, 13.2 ©

COMBINATION GEAR © RATCHET, RD

Ribbon Feed Roller

Ribbon Pressure Roller

Epson Dx4450 Circuit Springs
Ribbon Brake Spring

COMBINATION GEAR ©

COMBINATION GEAR ©

+2 -1

Responses

  • weldon
    How it work paper friction feeder diagram?
    3 months ago

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