Page 9 - MF3010Series Service Manual (Rev.0) (1)-017-045 (1)

2 Technical Overview > Laser Exposure System > Controlling the Laser Activation Timing > Horizontal Sync Control
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Controlling the Laser Activation Timing The engine controller sends the laser control signals (CNT0, CNT1) for changing the
operation mode of the laser to the logic circuit in the laser driver IC, as well as the video
■ Laser ON/OFF Control signals (VDO, /VDO) for image formation.
The laser driver IC executes laser control according to the combination of the CNT0, CNT1
In this control, the laser driver turns on/off the laser diode (LD) according to the laser control
signal sent from the engine controller. signals.
The following is the circuit diagram of the laser control. The following is the combination of the laser control signal (CNT0, CNT1).
Operation mode CNT0 CNT1 Remarks
Laser driver PCB Discharge L L The capacitor (C1) is discharged.
/BDI Data output H H At normal print
BD Sensor APC H L At using APC
+3.3V Forced OFF L H At using image mask
T-2-3
■ Horizontal Sync Control

This is the control to adjust the writing position in the image horizontal direction.
PD LD The following is the details of control procedure.
Engine
Controller 1) The engine controller controls the laser control signal during unblanking (*) to emit the laser
diode (LD) forcibly.

2) The BD PCB exists on the scanning route of the laser beam, which is sent to the BD PCB.
CNT1
Comparator 3) The BD PCB detects this laser beam, creates BD input signal (/BDI) and sends it to the
CNT0 engine controller.
4) The engine controller creates horizontal sync signals (/BD) based on /BDI signal and sends
the /BD signal to the main controller.
5) When /BD signal is input, the main controller outputs the video signal (VDO, /VDO) to the
Sample hold engine controller to adjust the writing position in image horizontal direction.
Logic PCB
/BD circuit
*: Unblanking period
The period during which the laser diode is emitted in non-image area.

C1
VOD
Main
Controller Drive
/VOD circuit

Laser driver IC

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2 Technical Overview > Laser Exposure System > Controlling the Laser Activation Timing > Horizontal Sync Control