COPYRIGHT
©
2000 CANON INC. 2000 2000 2000 2000 CANON iR5000/iR6000 REV.0 JULY 2000
CHAPTER 3 LASER EXPOSURE SYSTEM
3-1 P
1. Outline of Operations
1.1 Outline
The laser exposure system consists of a laser unit and a laser scanner: the laser unit is the
source of laser light, while the laser scanner serves to generate a scanning laser beam by
means of a polygon mirror.
The video signals from the controller unit are converted into laser drive signals by the DC
controller PCB; they are then turned into laser intensity signals by the laser driver PCB,
used to direct the laser beam from the laser unit.
The collimator lens turns the laser beam into a parallel beam possessing an oval cross sec-
tion; the cylindrical lens then changes it to a flat, band-like parallel beam.
The resulting laser beam is directed through an imaging lens and is reflected by a polygon
mirror, which is rotating at a high and by, upon by which the beam is turned into a scanning
beam possessing a specific direction.
The laser beam is then led through an imaging lens for removal of distortion, and is di-
rected to the positively charged photosensitive drum (areas representing white) for the for-
mation of a static image.
The laser beam is also used to blank out the non-image area.
T03-101-01
Item
Laser intensity control
Laser scanning
Laser scanner motor control
Description
1. Executes laser power auto control (APC control)
2. Executes optimum intensity control to suit the surface
potential of the drum
By semiconductor laser
Main scanning direction: control by BD signal
Sub scanning direction: control by laser write start signal
1. Executes constant speed rotation control
2. Switches between full-speed rotation and in-wait rota-
tion
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