Epson Stylus Photo785EPX, Service Manual

Page: 38 / 192

EPSON Stylus PHOTO 895/785EPX/915/825 Revision B
Operating Principles Overview 38
Paper loaded from ASF is advanced by the following roller.
†
Paper feed roller & Paper guide roller (assembled on the Top Frame)
→
Paper
eject roller & Star wheel roller (assembled on the Paper eject frame).
Additionally, the top & end of the paper is detected with the PE sensor.
In case the PE sensor dose not detect the paper in the paper loading sequence, the
printer detects the “Paper out error”. If the paper is detected after complete the paper
eject sequence, the printer detects the “Paper jam error”.
2.1.5 Paper Loading Mechanism (ASF Unit)
The Paper loading mechanism is positioned at the printer rear. The Paper loading
mechanism loads paper at the ASF unit and feeds paper to the PF roller.
This ASF unit consists of ASF motor, LD roller, Pad holder (Paper return plate), ASF
Frame, Hopper, and so on.
Table shows the ASF motor specifications.
For the major feature of this ASF unit, ASF HP sensor is not used and the single LD
roller is built in the ASF unit.
Drive sent from the ASF motor is always transmitted to the ASF unit side. But, the
Change lever and the Clutch mechanism switch ON/OFF drive to the LD roller.
Drive from the ASF motor is transmitted to the ASF unit as described below:
†
Switch the ASF motor drive to ASF unit side
ASF Motor pinion gear rotates CCW direction with a specific steps
→
Combination Gear 14.4, 38.4 (CW)
→
Combination Gear 37.6, 44.4 (CCW)
→
Spur Gear 23.2 (CW)
→
Spur Gear 35.2 (CCW)
→
Release the Clutch
mechanism lock position
Table 2-4. ASF Motor Specifications
Item Description
Motor type 4-Phase/ 200-Pole HB Stepping motor
Drive voltage +42 V +/ - 5% (DRV IC voltage)
Coil Resistance 7.8
Ω
+/ - 10% (25°C, per phase)
Inductance 13.5 mH +/ - 20%(1kH 1Vrms)
Driving method Bi-Polar drive
Driver IC LB11847