Canon imageRUNNER ADVANCE C5500 Series, Service Manual, Page: 85 / 1331

APC (Auto Power Control)
Purpose
Ensures constant laser beam light intensity for each line.
Execution timing
For each line (before writing the image)
Control description
1. The DC Controller outputs the laser control signal to the Laser Driver IC of each Y/C Laser Driver PCB.
2. The APC mode is set for the Laser Driver ICs of each Y/C Laser Driver PCB and the laser diode of each color is forcibly
activated. Each Laser Driver IC simultaneously monitors the laser diode (LD) with the Photo Diode (PD) and adjusts output
of laser diode until the laser light intensity reaches a specified level.
LD
PD
㼅㻌
Laser
Control Signal
LD
PD
㻹㻌
Laser
Control Signal
LD
PD
Laser Scanner Unit 1
Laser Scanner Unit 2
㻯㻌
Laser
Control Signal
LD
PD
㻮㼗㻌
Laser
Control Signal
Y
㻌
Laser
M
㻌
Laser
C
㻌
Laser
Bk
㻌
Laser
DC Controller
(UN1)
Laser Driver
PCB (Y)
Laser Driver
PCB (C)
㼅㻛㻹
Laser
Control
Signal
㻯㻛㻮㼗
Laser
Control
Signal
Laser Scanner Motor Control
Purpose
Rotates the Scanner Mirror at a specific speed.
Execution timing
At power-on, and at each print
Control description
Scanner Motor rotation speed is controlled by the Y/C Laser Driver PCB.
1. The Y/C Laser Driver PCB outputs Scanner Motor control signals (acceleration signal: ACC, deceleration signal: DEC) to
the Scanner Motor to rotate the Scanner Mirror.
2. The Y/C Laser Driver PCB detects the acceleration detection signal (FG1 to 2, BD_YM, BD_CBk) and controls the
acceleration signal (ACC1 to 2) and deceleration signal (DEC1 to 2) to keep the specified speed in comparison with the
reference signal in the Main Controller.
2. Technology
71