Xerox Phaser 3300, Servce Manual

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2-16 Phaser 3300MFP Service Manual
Theory of Operation
Safety Features
■
To prevent overheating
■
1st protection device: H/W cuts off when detecting an overheating
■
2st protection device: S/W cuts off when detecting overheating
■
3st protection device: Thermostat cuts off power to the lamp
■
Safety device
■
Fuser power is cut-off when the front cover is open
■
LSU power is cut off when the front cover is open
■
The temperature of the fuser cover's surface is maintained at less
than 80ºC to protect the user and a caution label is attached where
the customer can see it easily when the rear cover assembly is
opened.
LSU (Laser Scanner Unit)
The LSU unit is controlled by the 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 a 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.
Each facet of the polygon mirror scans a single line.
Item Specification Item
Resolution Real 600 dpi main direction x sub direction
Spot Size Main
75 + 20/-20
μ
m
-beam diameter at the level
of 1/e2 of intensity
-at the spot location of 0,
±
100 mm of image height
Sub
85 + 25/-25
μ
m
Variation
40
μ
m/50
μ
m
main/sub, within image height of -
100 ~ +100 mm range
Laser Property Wavelength 785 + 10/-15 nm at 25 °C
Power
0.33 mW
±
0.02 mW
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 mm
f
θ
Property
Magnification error Max 0.7% based on the printable area,
216 mm
Partial Magnification error max 1.5% based on the 2.54 mm width within
the printable area,
216 mm