COPYRIGHT © 2001 CANON INC.
2000 2000 2000 2000
CANON SmartBase PC1200s/iR1200s REV. 0 DEC. 2001
CHAPTER 4 OPERATION
4-8
Horizontal Sync Signal Control
When the laser beam reaches the horizontal print start position, the laser beam detection
signal (BDI*) from the laser scanner unit is detected, and the horizontal sync signal (BD0*)
is sent to the image processor PCB. Also, the horizontal sync signal (BD*) is monitored for
frequency of output.
Scanner Motor Control
The scanner motor is controlled so that the horizontal resolution of the print image is 600
dpi. Also, the laser beam detection signal (BDI*) from the laser scanner unit is detected to
monitor the rotation of the scanner motor.
Cartridge Detection Mechanism
In wait state, the CPU on the DC controller PCB measures the voltage level of the car-
tridge detection signal (CRGSNS) a specific number of times to check the presence/absence
of the cartridge when an AC bias is applied to the primary charging roller.
Toner Level Detection Mechanism
While the machine is in wait state, the toner level detection signal (ADDTNR; based on
the comparison of the developing bias output and the antenna output inside the cartridge)
occurring when the developing AC bias is detected during normal rotation to monitor the
toner level inside the cartridge.
1.3.2.3 Control Panel PCB
Key Detection and LCD/LED Drive
The keys are monitored, and the LCD and LEDs are driven.
LCD Function
The LCD consisting of 2 lines of 20 characters is controlled according to the display sig-
nals from the image processor PCB.
Serial Communication Control
The state of the control keys is monitored based on serial communications with the image
processor PCB. LCD and LED drive data are received.
1.3.2.4 Power Supply PCB
Switching Regulator
The following is generated using power from the power outlet for loads: +24 DC, +12
VDC, +5 VSDC, +5 VDC, +3.3 VSDC, +3.3 VDC.
