Specifications

System Overview
Samsung Electronics
Service Manual
3-13
3.2.6 LSU (Laser Scanner Unit)
The LSU unit is controlled by video controller. It scans the video data received from video controller with laser beam by
using the rotation principle of the polygon mirror to create the latent image on the OPC drum. It is the core part of LBP.
The OPC drum rotates as the same speed as the paper feeding speed. It creates the /HSYNC signal and sends it to the
engine when the laser beam of the LSU reaches the end of the polygon mirror, and the engine detects the /HSYNC signal
to arrange the vertical line of the image on the paper. After detecting the /HSYNC signal, the image data is sent to the
LSU to arrange the its margin on the paper.
The one side of the polygon mirror is one line for scanning.
Item Specification Item
Resolution Real 600 dpi main direction
sub direction
Spot Size Main 75 +20/-20
-beam diameter at the level of 1/e2
of intensity
-at the spot location of 0,
100 of image height
Variation 40
/50 main/sub, within image height of
-100 ~ +100
range
LaserProperty Wavelength 785 +10/-15
at 25
Power 0.33 0.02 at the center of image on the
focal plane, with stationary condition,
power supplied at
DC 5 volt
Vignetting Min 80 % spot power variation within image
height of -100 ~ +100
f Property Magnification error Max 0.7 % based on the printable area,
216
Partial Magnification error max 1.5 % based on the 2.54 width within the
printable area, 216
Beam Position Deviation of main scanning 1.0 at the center of image
Deviation of sub scanning
1.0
Scan Line Bow Max 1 within image height
Property Skew Max 1
-100 ~ +100 range
Sync. Property Position 136.7
1.0 distance to synchronization position
from the center of image
Pulse width Min 5.0
sec pulse width of synchronization
Pitch Error Neighbor line Max 10
Pitch error in sub scanning direction
within image height of
-105 ~ +105
range
Within 6 lines Max 20
within image height of
-105 ~ +105
range