Chapter 55-3The following table shows combinations of laser control signals (CNTRL0, CNTRL1, and CNTRL2).T-5-35.2.1.2 Horizontal Synchronization Control 0017-3096The 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 synchronizationsignal 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 /BDsignal 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 trailingedge of paper at the end of the continuous /BD signal.5.2.2 Controlling the Intensity of Laser Light5.2.2.1 Automatic Photocurrent Control (APC) 0017-3097The 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.Laser control signal Laser status DescriptionCTL2 CTL1 CTL0 Laser A Laser B0 0 0 OFF OFF Laser control OFF1 1 1 Video signal inputenableLaser beams can be emitted inresponse to video signals.1 1 0 ON OFF Forced emission of laser A (foradjustment in factory)1 0 1 OFF ON Forced emission of laser B (foradjustment in factory)1 0 0 ON ONForced emission of laser A andlaser B (for adjustment infactory)0 1 0 ON OFF APC over laser A0 0 1 OFF ON APC over laser B0 1 1 OFF OFF Forced stop of laser emissionMEMO:About Generation of BD SignalThe 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.
