Service manual

EPSON Stylus &2/25 1520
Rev. A
2-
6
2.2.4 Paper Feed Mechanism
The paper feed mechanism of this printer consists of the integrated ASF (Auto Sheet Feeder) mechanism,
tractor mechanism, PF (Paper Feed) motor, front/rear PE (Paper End) sensors, PF roller, paper guide
mechanism, paper eject unit, and PF motor drive disengage mechanism. The torque from the PF motor
drives the paper load mechanism, paper feed mechanism and paper eject mechanism. While the printer
is not printing, the PF motor drive disengage mechanism switches the torque from the PF motor to the
pump mechanism, which depends on the CR position. While the paper feed mechanism is driven, the
torque from the PF motor is transmitted via PF motor pinion gear and disengage gear to the PF roller.,
where the torque is then divided into 2 directions. One is transmitted to the paper eject mechanism via the
gear train in the paper guide assembly. The other is transmitted to the ASF mechanism via the
transmission gear.
The tractor drive gear train is set at the left end of the PF roller. Table 2-4 and Table 2-5 shows the
specification for the PF motor and PF motor drive terms, respectively. Figure 2-5 illustrates the paper feed
mechanism.
Item Description
Motor type 4-phases / 96-pole / HB type stepping motor
Drive voltage
42 VDC ± 5% (The voltage applied to the driver)
Coil resistance
10 Ω ± 10% (at 25° C per 1 phase)
Connection Bipolar
Excitation mode 2-2 phase, 1-2 phase, W1-2 phase constant current drive
Minimum step 1/720 inch / step (2-2 phase drive)
Operation
mode
Acceleration Constant Deceleration Stand-by
Paper feed
/LQHIHHGLQFK
0.9/0.9 0.9 0.75/0.75 0.6
ASF Feed 0.9/0.9 0.9 0.75/0.75 0.6
Pump driven
 /0.9
0.9 0.9 0.6
Pump driven
(slow)
 / 
0.9
 / 
0.6
Note) Double 1-2 phase drive / 2-2 phase drive
Table 2-4 PF Motor Specification
Table 2-5 PF Motor Drive Terms
Tractor Disengage Gear
PF Motor
PF Motor Pinion Gear
Disengage Gear
To the tractor
mechanism.
To the ASF
mechanism.
ASF
Transmission Gear
PF Drive Roller
Paper Eject Roller Shaft
Pump Mechanism
Paper Eject Roller Shaft
Paper Eject Roller Unit
Figure 2-5. Paper Feeding Mechanism