Laser Scanner Motor Control - Canon imageRUNNER ADVANCE C350 series Service Manual

2
Technical Explanation > Laser Exposure System > Various Controls > Laser scanner motor control
■ Vertical Scanning Synchronous Control
● Purpose
This is to align the writing start position in vertical scanning direction.
● Execution timing
Per printing
● Control detail
1) When the DC controller receives a print command, it creates the vertical synchronous
signal (/TOP) based on the inner timer and sends the signal to the main controller.
2) After receiving /TOP signal, the main controller counts the horizontal scanning synchronous
signal (/BD0) and outputs the video signal for 1 page of each color (DATA_Y, DATA_
M, DATA_C, DATA_K) to the DC controller in the specified number of times of horizontal
scanning.
As a result, the laser driver of each color emits the laser beam from the specified position for
1 page.
Laser
Main Controller PCB (UN81)
Video signal
APC signal
Y_PVREQ
Video signal
M_PVREQ
ASIC ASIC
C_PVREQ
Bk_PVREQ
2 Technical Explanation > Laser Exposure System > Various Controls > Laser scanner motor control
Laser
Laser
Laser
DC Controller
PCB (UN04)
ITOP
CPU
Laser ON/OFF signal
F-2-64

■ Laser scanner motor control

● Purpose
This is to rotate the scanner mirror by the specified speed.
● Execution timing
At power ON, Per printing
● Control detail
The rotation speed of the Scanner Motor is controlled by the DC Controller.
1) The DC Controller outputs the Scanner Motor control signals (acceleration signal: ACC,
deceleration signal: DEC) to the Scanner Motor to rotate the Polygon Mirror.
2) The DC Controller controls the rotation speed of the Scanner Motor to keep it constant by
using the Scanner Motor rotation speed signal (FG signal) as a reference.
(During the period from the Scanner Motor rotating until the motor reaches the target
revolution and the printer starts the image formation process)
3) If the laser is emitted during image formation, the DC Controller detects the BD signal.
4) The DC Controller controls the Scanner Motor control signals (acceleration signal: ACC,
deceleration signal: DEC) based on the input timing of the BD signal to control the rotation
speed of the Scanner Motor.
ACC
DEC
FG
BD
BD Sensor
DC Controller
PCB(UN04)
Y/M/C/K
Laser Driver
PCB (UN05)
2-50
Bk Laser
C Laser
Scanner
Motor
M Laser
Y Laser
Laser Scanner Unit
F-2-65
2-50