Belt Drive Motor Circuit - Ricoh DF56 Service Manual

30 November 1990

6.8 BELT DRIVE MOTOR CIRCUIT

DF Main Board
Speed
Data
ON/OFF
CPU
Forward/
Reverse
A dc servomotor is used as the belt drive motor. The driver IC controls the
speed of the belt drive motor. The CPU sends the speed data (programmed) to
the driver IC. The driver IC sends the pulse-width-modulation (PWM) signal to
the driver circuit, which sends the motor drive pulses.
An encoder in the servomotor has two magnetic sensors that generate two
pulse signals (phase A and B). The driver IC monitors the belt speed and direc-
tion by these pulse signals and uses this data to regulate the motor's speed.
PWM
Driver
Driver
Circuit
IC
+5V
Phase A
Phase B
7-18
CN102-1
Belt Drive
CN102-2
CN103-1
CN103-2
Encoder
CN103-3
CN103-4
Motor