Canon NP2120 Service Manual page 42

The copier is controlled by the two microprocessors
and communication LSI on the DC controller PCB,
. Controls the copy sequence.
. Controls the document size identification.
Q302 (slave)
. Controls the stepping motor.
. Outputs the image formation control signals.
Q304 (IPC)
. Controls the serial communication with ADF
and sorter.
Note:
With the built-in A/D converter, the copie&
microprocessors can read both digital and
analog signals.
Note:
The main motor (Mi) is a synchronous motor
thatusesthefrequencyofthepowersupplyas
motor (M3), on the other hand, are stepping
the crystal oscillator built in the DC controller.
As such, luctuations in the power supply fre-
quency during copy operation in turn fluctuate
the main motor (MI), causing the copies to
carry expanded or contracted images.
C A N O N NPZl20/2MO RN.0 M A Y 1990 PAINTEO I N J A P A N IIMPAIME AU JAPONI