Vertical Scanning Synchronization Control - Canon imageRUNNER ADVANCE C3500 III Series Service Manual

Table of Contents

Control description

1. The Y/M Laser Driver PCB forcibly emits the Bk laser diode of the C/Bk Laser Driver PCB by setting the Bk laser control

signal to APC mode.

2. The laser beam of the Bk laser has a BD circuit in the scanning light path, and is incident on the BD Circuit.

3. The BD Circuit detects the laser beam and generates a BD signal, and sends it to the Main Controller.

4. The Main Controller synchronizes with this signal, and sends video signals (Y_VDO, M_VDO, C_VDO and Bk_VDO) to the

Y/M and C/Bk Laser Driver PCBs while regarding the reference BD signal as the vertical scanning synchronous signal (BD)

for each line. This enables each Laser Driver PCB to emit a laser beam from a fixed position for each line.

• As the BD signal is the horizontal scanning synchronous signal of the Bk color, the Bk color serves as each color's

reference for horizontal scanning.

• With this machine, the reference in the horizontal scanning direction for Y and M colors is the right edge (right-to-left)

while that for C and Bk colors is the left edge (left-to-right).

Main Controller

Vertical Scanning Synchronization Control

Aligns the write start position in the vertical scanning direction.

Execution timing

At each print

Control description

1. When the DC Controller receives a print order, it detects an internal reference signal. Based on this signal, a vertical scanning

synchronous signal (ITOP) is generated and sent to the Main Controller.

2. The Main Controller synchronizes with ITOP signal and generates video signals (Y_VDO, M_VDO, C_VDO and Bk_VDO),

and sends them to the Laser Scanner Unit.

<Y, M color>

Right standard

C/K Laser Driver PCB

Y/M Laser Driver

<C, Bk color>

Left standard

2. Technology