Epson DLQ-3000+, Service Manual

Page: 71 / 262

Operating Principles
Rev. A
2-9
2.1.5 Paper Feed Mechanism
The paper feed mechanism consists of the platen roller, PF roller (Paper Feed roller), paper
eject roller, PF motor (Paper Feed motor), tractor unit, PEW sensor (Paper Width sensor),
front/rear paper sensor, release sensor, paper jam sensor, and paper shift mechanism.
2.1.5.1 Core of the Paper Feed Mechanism
This printer feeds paper by sliding it horizontally. Paper feed operation varies depending on
the release lever setting condition, as described below:
In the friction mode
Paper is held by the front paper bail and the for roller assemblies (2 upper and 2 lower
rollers) under the CR guide shaft.
Feeding method: Front feeding (automatic), Rear feeding (manual), CSF feeding
Ejecting method: Front ejection
In the tractor mode
Switching the lever setting from the friction mode to the tractor mode puts the printer into
the tractor mode. In the tractor mode, the drive is disengaged from the rollers by the
release mechanism, and transmitted to the tractor side.
Feeding method: Tractor
Ejecting method: Front ejection
In the paper jam removal mode
Torque is disengaged from all the rollers in this mode. (See Section 2.1.5.3.) A stepping
motor is used for the PF motor, which enables the paper to move to and stop at any
position regardless of the direction. The motor is controlled by the controller circuit by the
open-loop system. It refers to the signals output from the sensors in the mechanism to
determine the amount to slide paper and the corresponding motor pulse. Torque sent
from the PF motor equally splits to the front and rear paper feed drive rollers via the 2
timing belts. If the belt tension is inappropriate (either too loose or too tense), the front
and rear rollers lose balance and paper jam is caused as the result. To balance the belt
tension with each other, reinstall the PF motor to the proper position. The PF motor is
fixed with 2 screws and the adjusting part such as the PF tension shaft. (See chapter 3
for detailed procedure.)
P r i n t e r M e c h a n i s m F r a m e
T r a c t o r T r a n s m i s s i o n G e a r
T r a c t o r
P a p e r F e e d M o t o r
P l a t e n
P a p e r E j e c t D r i v e R o l l e r A s s e m b l y
P a p e r B a i l R o l l e r
S u b P a p e r F e e d R o l l e r
A s s e m b l y
P a p e r F e e d D r i v e R o l l e r
Figure 2-7. Core of the Paper Feed Mechanism