EPSON Stylus COLOR 860/1160 Revision C
Operating Principles Electrical Circuit Operating Principles 49
2.2.2.4 PF Motor Driver Circuit
TheStylus COLOR 860/1160 is equipped with a DC motor for the PF motor. In
addition to the CPU and ASIC, a slave CPU is mounted on the C298MAIN
board. Since the slave CPU is exclusively used to control DC motors, it
reduces duty of CPU and ASIC to offer faster data processing. The block
diagram for the PF motor driver circuit is as shown below:
Figure 2-22. PF Motor Driver Circuit Block Diagram
IC15 slave CPU controls paper feeding amount by referring to the encoder
pulses sent from IC8 ASIC. It also sets a proper drive current value according
to the paper feeding amount and direction. So it outputs specified control signal
to the motor driver. The motor driver IC19 outputs PF motor drive current to the
PF motor according to the control signals from the IC15 slave CPU.
Unlike a stepping motor, the DC motor that drives the PF motor can not detect
a paper feeding amount by referring to the pulses given. For this reason, a loop
scale is attached on the Gear 76 to mechanically detect a paper feeding
amount.
The loop scale encoder sensor outputs two kinds of TTL level pulses Phase A
and Phase B to IC8 ASIC.
Figure 2-23. Loop Scale Encoder Pulse
Rotational direction of the PF motor is determined by the phase between the
output waveforms of Phase A and Phase B. Refer to Figure 2-23 for different
phase for each direction.
NOTE: If the drive voltage for the PF motor reaches 1A, a fatal error occurs.
IC 1 9
A3958SB
IC 1 5
C 90A 13C A
IC 8
E05B70CD
PF-A
PF-B
+42V
C 116
0.22U
OUTA
OUTB
CP1
CP2
VREG
SENSE
C120
022U
C119
0.22U
GND
GND
GND
ENABLE
PHASE
MODE
RANGE
REF
OSC
CLOCK
DATA
STOROBE
PD3
PD1
PD0
PD4
DA0
+
-
SCON
PD6
PD5
PD7
P17
P15
P20
P21
NMI
NMI
P31
RXD1
P33TXD1
P32
CRBI3
P30
CRPHAB
P64CRENBB
RES
CRAI2
MD2
P25
CPU
IC 2 4
M 62552FP
R138
4.4B K
R139
4.99B K
C13
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