Dell 1135N Service Manual page 29

Product specification and feature
2.2.3.5 LSU (Laser Scanner Unit)
It is the core part of the LBP which switches the video data received to the controller to the electrostatic
latent image on the OPC drum by controlling laser beam, exposing OPC drum, by use of a polygon mirror.
The OPC drum is synchronized with the paper feeding speed. The /HSYNC signal is created when the laser
beam from LSU reaches the end of the polygon mirror, and the signal is sent to the controller.
The controller detects the /HSYNC signal to adjust the vertical line of the image on paper. The /HSYNC
signal is used to synchronize the image data with the left margin of the paper.
The one side of the polygon mirror is one line for scanning.
OPC Drum
Photo Diode
Polygon Mirror
Polygon Motor
Motor Driver
LD Driver circit
LD(Laser Diode)
Protector panel
2-17
Service Manual