Drum Motor Control Circuit - Printronix L5535 Maintenance Manual

Drum Motor Control Circuit

The drum motor drives the photoreceptor drum. Since the drum is central to
the printing cycle, stable rotation is required of the motor. A rotary encoder is
positioned on the rotating axis of this motor.
A crystal oscillator and frequency divider generate standard pulses that are
equivalent to a motor rotation of 1406.25 RPM. A phase-locked loop (PLL)
circuit compares the motor encoder output pulses with the standard pulses
from the frequency divider. The resulting error voltage changes the motor
drive voltage in such a way that the error voltage is minimized, which causes
the drum motor pulses to occur at the same rate as the standard pulses.
DRMP DRMN
Control Output
(0 to +8v)
Driver
Circuit (Lock Center
= +4V)
MC Board
DRMP:
DRMN:
DME:
DMON1:
DMARM0: Alarm signal to indicate rotation abnormality of
Drum Motor
Drum Motor Control Circuit
PLL Circuit
Frequency
Detector
Frequency
Dividing
Circuit
DMON1 DMARM0
Gate Array
CPU
Positive side of drum motor drive power supply
Negative side of drum motor drive power supply
Drum motor encoder output signal
Drum motor drive signal
drum motor
Drum Motor Control Circuit
Drum Motor Encoder (40 Pulses)
Sensor
Interface
Crystal
Oscillator
DME
II–185