Oki B721 User Manual page 115

Symptom
Horizontal lines
and spots appear
periodically.
White area of paper is
lightly stained.
Periphery of letters is
smudged.
The entire paper area
is lightly stained when
printing on envelopes or
coated paper.
Toner comes off when it
is rubbed.
Cause
If the interval of lines or spots
is about 94 mm (4 inches), the
image drum (the green tube) is
damaged or dirty.
If the interval of lines or spots is
about 37 mm (1.5 inches), foreign
materials may be present on the
image drum.
If the interval of lines or spots is
about 143 mm, there is damage to
the fuser unit.
The print cartridge has been
exposed to light.
The paper feed path is dirty.
The paper contains static
electricity.
The paper is too thick.
The toner is low.
The LED heads are dirty.
The paper is unsuitable.
The paper is moist.
The toner may be sticking to the
whole area of the envelope or
coated paper.
The settings of media type and
weight are incorrect.
Recycled paper is used.
The media weight setting is
unsuitable.
Remedy
Lightly wipe the image drum with
soft tissue paper.
Replace the image drum if it is
damaged.
Open and close the top cover, and
print again.
Replace the fuser unit.
Place the print cartridge back
into the printer and leave it for a
few hours. If that does not solve
the problem, replace the print
cartridge.
Print a few test pages.
Use paper stored in proper
temperature and humidity
conditions.
Use thinner paper.
For the models B721/B731:
Replace the print cartridge.
For the models ES7131/
MPS5501b: Replace the toner
cartridge.
Wipe the LED heads with soft
tissue paper.
Use supported paper.
Replace it with new paper.
This is not a malfunction of the
printer.
Coated paper is not
recommended.
Press the button and select
[Menus] > [Tray Configuration]
> the paper tray configuration
you are using, and then select the
proper values for [Media Type]
and [Media Weight]. Or, select a
larger value for [Media Weight].
Press the button and select
[Menus] > [Tray Configuration]
> the paper tray configuration you
are using, and then select a larger
value for [Media Weight].
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Image Quality Issues
Reference
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page 126
page 129
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page 130
page 122
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page 42
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page 122
page 124
page 134
page 38
page 42
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