Paper Feeding Mechanism - Epson Stylus PHOTO 950 Service Manual

EPSON Stylus PHOTO 950

2.2.3 Paper Feeding Mechanism

The Paper Feeding mechanism consists of components such as ASF, Manual Feed
Mechanism and Roll paper holder.
2.2.3.1 ASF Mechanism
The paper feeding mechanism consists of Paper feed motor (PF motor), PF roller,
Paper eject roller, Star wheel roller, and so on. The paper feeding mechanism feeds
paper loaded from ASF using the PF roller and Paper Eject Roller & Star wheel roller.
For this mechanism, the PF motor mentioned in the following Table 2-4 is used on this
product.
Table 2-4. PF Motor Specifications
Item
Motor type
Drive voltage
Coil Resistance
Inductance
PWM drive (PWM means Pulse Width Modulation)
Driving method
Combination gear
12, 16
PF rotary
encoder
OPERATING PRINCIPLES
Description
DC motor
+42V +/- 5% (DRV IC voltage)
30.5Ω +/- 15% (per phase at 25 degree)
22.8mH +/- 15% (1kH 1Vrms)
Spur gear 12
PF motor
pinion gear
Figure 2-4. Paper Feeding Mechanism 1
The paper feed motor used in previous models was a stepping motor and control was
carried out by means of open loop control. However, this printer employs closed loop
control via a DC motor and a rotary encoder to control the carriage speed and position
in order to improve the paper feeding accuracy. The rotary encoder is installed to the
left end of the PF roller shaft and controls the paper feeding amount. See "PF Motor
Driver Circuit" on page 50 of this chapter for details of the PF motor control circuit.
The PF motor drive force is transmitted to the PF roller and the paper eject roller along
the route described below.
PF roller drive force transmission route
PF motor pinion gear → PF rotary encoder → PF roller
Paper eject roller drive force transmission route
PF motor pinion gear → Combination gear 9.5, 14.7 → Paper eject roller
A diagram of the PF motor drive force transmission route, including the names of the
components included in this route, is shown on the following page. The paper is
transported along the following path by means of the above drive force transmission
routes.
Spur gear 21.5
Combination gear
9.5, 14.7
Printer Mechanism
Revision A
30