Epson Stylus Photo 925, Service Manual

Page: 47 / 167

EPSON Stylus Photo 925 Revision A
Operating Principles Electrical Circuit Operating Principles 47
2.2.2.3 ASF/Pump Motor Drive Circuit
The ASF/Pump Motor is a 4-phase 48-pole PM type stepping motor. The Motor Driver
IC (12 IC) drives the ASF/Pump Motor.
Based on the signal output from the CPU, the motor driver generates a motor drive
waveform to control the ASF/Pump Motor. At the same time, the motor driver IC
monitors the current to the motor and correct it if found abnormal.
When the printer has not received data for three minutes, the CPU sets the current to
the motor driver to “0” and turn off the motor driver for the sake of power saving.
Figure 2-24below shows the outline of the motor drive circuit.
Figure 2-24. ASF/Pump Motor Drive Circuit
2.2.2.4 Cutter Motor Drive Circuit
Like for the CR Motor and PF Motor, a DC motor is used as the motor for the cutter
mechanism, which is newly designed for this printer. Although the CR/PF motor drive
circuit detects the relevant unit position by the scale, the cutter drive circuit detects the
cutter position by the photosensors located at both ends of the cutter travel region.
Based on the signal from the photosensors, the CPU (IC11) sets an optimum current
value and outputs a special control signal to the motor driver IC (IC7) to drive the
motor. Then the motor driver IC (IC7) outputs the cutter motor drive current to the
Cutter Motor.
Figure 2-25 below shows the outline of the motor drive circuit.
Figure 2-25. Cutter Motor Drive Circuit
CPU (IC11)
E01A27CA
A
AA
A
‑A ‑A ‑A ‑A
B BB B
‑
‑‑
‑B
BB
B
Motor Driver IC
(IC12)
ASF/Pump Motor
+42V
CT Sensor
(CN15)
CPU (IC11)
E01A27CA
Motor Driver
IC (IC7)
CT-A
CT-B
CUT
Motor
CT1
CT2
+42V