Horizontal Synchronization Control; Controlling The Intensity Of Laser Light; Automatic Photocurrent Control (Apc); Controlling The Laser Scanner Motor - Canon iR2030 Series Service Manual

The following table shows combinations of laser control signals (CNTRL0, CNTRL1, and CNTRL2).

5.2.1.2 Horizontal Synchronization Control

iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018i
The purpose of this control is to adjust the position where scanning starts in the horizontal direction (main scan direction) of the image with reference to the hori-
zontal synchronization signal (/BD) sent from the BD sensor in the laser scanner. The horizontal synchronization signal is also used as a vertical synchronization
signal to recognize the leading edge of paper. Upon detection of arrival of the fed paper at the prescribed position, the DC controller PCB starts sending the /BD
signal to the image porcessor PCB. The image processor PCB recognizes the leading edge of paper at the start of the continuous /BD signal; it recognizes the trailing
edge of paper at the end of the continuous /BD signal.
MEMO:
About Generation of BD Signal
The BD sensor on the BD circuit board receives only the beam of laser B; it does not receive the beam of laser A. The BD signal is generated from the beam of laser A.

5.2.2 Controlling the Intensity of Laser Light

5.2.2.1 Automatic Photocurrent Control (APC)

iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018i
The purpose of this control is to monitor the laser beam emitted to the photodiode on the laser driver circuit board in order to adjust the light quantity.

5.2.3 Controlling the Laser Scanner Motor

5.2.3.1 Laser Scanner Motor Control

iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018i
Laser control signal Laser status
CTL2 CTL1 CTL0 Laser A
0 0 0 OFF
Video signal input
1 1 1
enable
1 1 0 ON
1 0 1 OFF
1 0 0 ON
0 1 0 ON
0 0 1 OFF
0 1 1 OFF
T-5-3
Description
Laser B
OFF Laser control OFF
Laser beams can be emitted in
response to video signals.
Forced emission of laser A (for
OFF
adjustment in factory)
Forced emission of laser B (for
ON
adjustment in factory)
Forced emission of laser A and
ON laser B (for adjustment in
factory)
OFF APC over laser A
ON APC over laser B
OFF Forced stop of laser emission
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