Scanner Motor Control - Ricoh FT4430 Service Manual

16 April '88

2. Scanner Motor Control

The scanner drive motor [M6] is a servomotor, The optics CPU on the main
board [PCB6] controls the speed of this servomotor. The main CPU and the
optics CPU communicate through a serial interface bus.
At the programmed time, the main CPU sends a scanner start signal to the
optics CPU. The optics CPU then checks the drum speed by monitoring the
pulses from the pulse generator. Based on this input, the optics CPU
determines the proper speed for the scanner drive motor. The optics CPU
sends the speed data to the timer IC which sends the motor drive pulses.
The. encoder on the servomotor has a photointerrupter that generates pulse
signals. The optics CPU monitors the scanner speed by these pulse signals
and uses this data to regulate the servomotor speed.
The home position sensor [S13] informs the optics CPU whether the first
scanner is in the home position.
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