Xerox FaxCentre F116, Service Manual

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General Procedures/Information
6-42 9/04 FaxCentre F116/F116L
GP 12 Laser Exposure
Laser exposure is the process of creating an invisible static charge image on the Drum by the
laser beam emitted from the ROS Unit.
This process is controlled as follows in order to appropriately time image printing.
Figure 1.
In the sub-scanning direction (vertical direction)
• When the print engine receives the PRINT signal, the Polygon Motor and the Main Drive Motor
rotate and the paper is fed.
• The printing in the sub-scanning direction is started when the Print Engine Board sends the
VIDEO signal to the ROS a certain time after the leading edge of the paper activates the Paper
Sensor (TOD signal).
• The print starting position for the 2nd line is decided by delaying the VIDEO signal sending tim-
ing.
In the scanning direction (horizontal direction)
• The SOS Sensor is installed on the Laser Diode Control Board to unify the laser emission tim-
ing for each scan line.
PRINTING AREA
• The controller sends the VIDEO signal at the appropriate paper size to the engine (Print Engine
Board).
• The controller determines the start point of printing according to the TOD signal (sub-scanning
direction) sent from the engine (Print Engine Board) and the HSYNC signal.
• Laser exposure is started when the print head receives the VIDEO signal.
4110s032
4127s036
ROS Unit
Drum
SOS Sensor
(PWB-LD2)
Laser Diode
Polygon Motor (M3)