Canon imageRUNNER C1335 Series Service Manual page 64

2
Technical Explanation > Laser Exposure System > Various Controls > Horizontal scanning synchronous control
■ Horizontal scanning synchronous control
● Purpose
To align the writing start position in horizontal scanning direction.
● Execution timing
When printing starts (per line)
● Control detail
1) DC Controller forcibly emits the laser diode on Y/M/C/Bk Laser Driver PCB by setting the
laser control signal of Bk -laser to APC mode.
2) The BD Circuit is located on the scanning light path of the laser beam of the Laser Bk, and
the laser beam is emitted to the BD Circuit.
3) The BD Circuit detects the laser beam and then generates a BD signal, and sends it to the
DC Controller.
4) The DC Controller performs synchronization based on this signal, and then sends a
reference BD signal to the Main Controller as the horizontal scanning synchronous signal
(BD) for every line.
5) When the Main Controller receives these signals, it outputs the video signals (Y_VDO, M_
VDO, C_VOD, and Bk_VDO) to the DC Controller. This enables the Y/M/C/Bk Laser Driver
PCB to emit a laser beam from a fixed position for every line.
NOTE:
• Since the BD signal is the horizontal scanning synchronous signal of the Bk color, the Bk
color is the reference for horizontal scanning of each color.
<Y, M color>
Feeding
direction
Left standard
2 Technical Explanation > Laser Exposure System > Various Controls > Horizontal scanning synchronous control
<C, Bk color>
Right standard
F-2-44
DC Controller
PCB (UN04)
Main Controller
PCB (UN81)
Bk_VDO
C_VDO
M_VDO
Y_VDO
BD
BD Sensor
Bk Laser
Y/M/C/K
Laser Driver
PCB (UN05)
C Laser
M Laser
Y Laser
2-33
F-2-45
2-33