Drive Circuit; Paper Feed Motor Control/Drive Curcuit - Epson DFX-8000 Service Manual

2.3.8 Paper Feed Motor Control/Drive Circuit
Figure 2-22 shows a block diagram of the paper feed motor control\ drive circuit.
The paper feed motor is an HB type pulse motor driven with 1-2 phase excitation, and can be rotated
in either the forward or reverse direction and stopped at any position. The phase signals are output
from four pins of the CPU to the driver board.
The paper feed motor is driven in any of the following three modes:
Micro step mode (during forward or reverse micro adjusting)
Middle speed mode (during forward or reverse feeding)
High speed mode (only during forward feeding)
Switching among the above three modes is executed by changing the current applied to paper feed
motor driver STK67 13B. The drive current switching signal (PF H/R, which is the common current
the reference voltage for the internal chopper controller, is set to the output voltage level of the drive
current select circuit. The drive current select circuit switches the output voltage level in accordance
with the PF H/R signal. Table 2-21 shows the circuit specifications.
Table 2-21. Paper Feed Motor Control/Drive Circuit Specifications
Supply voltage
Current consumption (per phase)
Drive frequency
Driving method
Paper feed pitch
Paper feed speed
I
I
POO-3 '
1
#
1
I
CPU
L - - - - - - - -
M A I N B O A R D
36.5 & 1 VDC (voltage applied to the driver circuit)
1.75 & 0.20 A (driving, average)
0.20 & 0.02 A (holding)
2610 PPS (Middle speed mode, constant speed)
4274 PPS (High speed mode, constant speed)
Chopper constant current drive, 1-2 phase excitation
1/2 16" (O. 12 mm): 2 steps
1/6" (4.23 mm):
1/8" (3. 18 mm):
1/9" (2.82 mm): 48 steps
1.7 IPS (Micro step mode)
6.0 IPS (Middle speed mode)
9.9 IPS (High speed mode)
1
1
1
1
1
n
,
E05A16GA
1
Figure 2-22. Paper Feed Motor Drive
72 steps
54 steps
- - - - - - - - - - - - - - - - - - -
1
1
1
1 L - - - - - - . .
1 4 - 1 - - - - - - -
RF MOTOR
DRIVE
I
CIRCUIT
1
STK6713B ~
I
D R I V E R B O A R D
2-33
I
1
- - q
PF
J
/ / / ~
////
Modes
MOTOR