Paper Advance Mechanism - Epson LQ-670 Service Manual

Chapter 2 Operating Principles

2.1.4 Paper Advance Mechanism

The paper feed mechanism of this printer consists of the platen roller, paper feed roller, paper eject roller,
PF motor, tractor unit, PW detector, PE (rear/front) detectors, release detector, and CSF
mechanism(option). This printer performs paper advance by moving the paper horizontally.
2.1.4.1 Paper Advance Mechanism
Driving force of the PF motor is conveyed through the paper feed gears to roller assembly, paper eject
drive, paper bail roller, platen roller, roller assembly, PF support and roller, PF drive, and advances paper.
The driving force conveyed to the tractor gear is sent to the CSF drive gear in case the CSF is mounted.
Also, the tractor transmission gear conveys driving force to the tractor gear by the release mechanism and
enables the push tractor to feed the paper.
‰Friction Advance Mechanism
The paper is held between paper eject and the roller assemblies located under the carriage guide
shaft (2 for each up and down; total 4)
„Paper Load
„Paper Eject
‰Push tractor Mechanism
By changing the release lever from the cut sheets position to the continuous paper position manually,
the mode is changed from friction mode to tractor mode. In the tractor mode, the driving force for
paper load is conveyed to the tractor side, and the contact to the roller is lost by the release
mechanism.
„Paper Load
„Paper Eject
Category
Type
Coil Resistance
Drive Voltage
Drive Method
Micro paper sending
Drive Frequency
Rated Current
2-6
Figure 2-4. Paper Advance Mechanism
: Front automatic feed (manual feed), paper load from the CSF
: Front paper eject
: Tractor
: Front paper eject
Table 2-4. Paper Advance Specification
2-phase 96 poles Hybrid type Stepping Motor
16.0
42V
Bi-pola constant current drive
1-2, 2-2 phase, W1-2 phase,
1/360 inch(1-2 phase)
600 7000Hz
0.535A (constant speed)
Specification
10% (at 25 C, per phase)
5%
Rev. A