Vertical Scanning Synchronization Control - Canon imageRUNNER ADVANCE C5500 Series Service Manual

Control description
1. The Main Controller forcibly activates the laser diode of the M Laser Driver PCB by setting the M laser control signal to APC
mode. Similarly, the Main Controller forcibly activates the laser diode of the Bk Laser Driver PCB by setting the Bk laser
control signal to APC mode.
2. The BD Sensor (YM) is located on the scanning light path of the laser beam of the M laser, and the laser beam is incident
on the BD Sensor (YM). Similarly, the BD Sensor (CBk) is located on the scanning light path of the laser beam of the Bk
laser, and the laser beam is incident on the BD Sensor (CBk).
3. The two BD sensors detect the laser beam, generate BD signals (BD_YM, BD_CBk), and then send them to the Main
Controller.
4. The Main Controller outputs video signals (VDO_Y, VDO_M, VOD_C, VDO_Bk) to each Laser Driver PCB when it receives
these BD signals. This enables the laser driver to emit a laser beam from a fixed position for each line.

Vertical Scanning Synchronization Control

Purpose
Aligns the write start position in the vertical scanning direction.
Execution timing
At each print
Control description
1. The DC Controller detects an internal reference signal when it receives a print order. 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 VDO signals (Y_VDO, M_VDO, C_VDO and Bk_VDO),
and sends them to the Laser Scanner Unit.
3. The Laser Scanner Unit generates the laser drive signals based on the VDO signals. At this timing, the Laser Scanner Unit
emits laser beams to match the leading edge of image with that of paper.
Main
Controller
VDO_Y
BD_YM
VDO_M
Main Controller
VDO_C
BD_CBk
VDO_Bk
ITOP
Reference
signal
Print
instruction
DC
Controller
(UN1)
VDO signal
Laser Scanner Unit 1
Y Laser Driver
Y Laser
PCB
BD Sensor (Y, M)
M Laser Driver
M Laser
PCB
Laser Scanner Unit 2
C Laser Driver
C Laser
PCB
BD Sensor (C, Bk)
Bk Laser Driver Bk Laser
PCB
Laser Laser
Laser drive signal
70
2. Technology
Laser Laser
Laser drive signal