Canon EF-9, Service Manual

Page: 17 / 54

I. BASIC OPERATION
A. Outline
The envelope feeder feeds envelopes into the printer.
The envelope feeder is controlled by the pick-up commands (1st Start and 2nd Start) sent
from the DC controller in the printer.
Operation sequences of the envelope feeder are controlled by the envelope feeder driver PCB.
A 4 bit microcomputer (CPU, IC932) and a gate array (G.A., IC931) are installed on the PCB. The
CPU serially communicates with the DC controller in the printer via the gate array.
The CPU drives the pick-up motor in response to the pick-up commands (1st Start and 2nd
Start) sent from the DC controller.
+24VDC is supplied to the envelope feeder from the printer. +5VDC for the ICs and sensors
is generated within the envelope feeder driver PCB from this +24VDC.
The flow of the signals between the envelope feeder and the printer is shown below.
Figure 2-1-1
2 - 1
CHAPTER 2
IC 931
Gate array
Bus
Envelope feeder driver PCB
+24VA
Printer
IC 932
CPU
DC controller PCB
Serial line
Envelope feeder
paper sensor
Motor drive
circuit
Pick-up motor