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AR-651/810 FUSER UNIT 14 - 11
14. 5. Fuser Motor Drive
14. 5. 1. Outline of operation
(1) The LGC transmits control signals for the fuser motor rotation (HTRMT:Motor rotation command).
(2) The excited phase switching unit excites each phase on the fuser motor. Fuser motor rotates.
(3) Hall elements A to C are used to detect the rotation position of the motor (or rotor).
(4) The excited phase switching unit switches the excitation for each phase. (By repeating steps (2)
through (4) above, the motor keeps rotating.)
(5) An FG pulse is generated by the rotation of the fuser motor.
(6) The phases and velocities of the FG pulse and the reference frequency from the LGC are compared,
and the differences are added up. In addition to this are added the fluctuations in the supply voltage
(Signal generation).
(7) The switching timing for the excited phase switching unit is changed to match the signal obtained in
step (6). That is, control ensures that the FG pulse and reference frequency are equal. The fuser
motor rotates at a constant speed (locked range state).
(8) When the HTRML signal changes to “H” level, the fuser motor stops rotating.
(9) During standby, the HTRML level changes to “L” if the temperature of the pressure roller drops below the
reference temperature, and the fuser motor rotates at a low speed.
+5.1V
+36A
W
V
U
A
C
B
M/DC-HTR-340N
Reference
frequency
(HTRCK)
Control
signal
HTRML
HTRMT
HTRMT
Wave
shaping
Phase
comparator
Speed
comparator
Difference
Current
detecting
circuit
detecting
circuit
Rotation
control
Excited
phase
switching
unit
Rotor
position
detection
position
detection
Fuser motor
FG pulse
U, V, W : Phase
A, B, C : Hall element
Difference
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