Laser Exposure - MINOLTA-QMS PagePro 1200 Series Service Manual

PagePro 1200 Series Mechanical / Electrical
4-4.

Laser Exposure

Laser exposure is the process of creating an invisible static charge image on the PC Drum by the
laser beam emitted from the Print Head Unit.
This process is controlled as follows in order to appropriately time image printing.
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In the sub-scanning direction (vertical direction)
• When the printer receives the PRINT signal, the Polygon Motor and the Main Motor rotate and
the paper is fed into the printer.
• The printing in the sub-scanning direction is started when the Controller Board sends the VIDEO
signal to the Print Head a certain time after the leading edge of the paper activates the Paper Sen-
sor (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 timing
for each scan line.
Print Head Unit
Polygon Motor (M3)
50
PC Drum
SOS Sensor
(PWB-LD2)
Laser Diode
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