Control Panel Pcb; Power Supply Pcb - Canon iR1200 Series Service Manual

CHAPTER 4 OPERATION
Laser Control Block
The laser control block controls the drive of the laser diode of the laser scanner unit ac-
cording to the image signals (VD0, VD0*) from the image processor PCB. Also, it controls
the intensity of the laser diode (auto power control) for each line of print data.
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.
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COPYRIGHT © 2002 CANON INC. 2000 2000 2000 2000 CANON iR1200/iR1300 Series REV. 0 AUG. 2002