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Digital Printing FAQ's
Help & Advise - Printer
Frequently discussed printer related topics
Banding
during printing
Generally the printer should print slower for high quality
prints when it is outputting
more ink and faster for lower quality prints when less ink is being
used.
Consistant horizontal banding is something that may appear
when
printing areas of solid colour
if the ink is being put down too fast for it to dry adequately before
the next print pass.
The result is the overlap of ink on the subsequent bi-directional pass
forming the banding.
To alliviate this effect either use a slower print speed or
re-print using a setting
that uses less ink or switch to printing in a uni-directional mode.
Check that the correct profile is being used.
Wider horizontal banding issues more commonly seen at the edges of
the roll (or may appear as a watermark) can be caused when the roll of
media has been stored on it's side instead of being stored vertically
on end or when the roll has been rested on the printers feeder rollers
overnight.
Very narrow horizontal banding (may also appear as fuzzy text) may
be the result of innaccurate printer nozzle alignment and the nozzle
cleaning function should be performed until a solid colour is acheived.
Vertical banding in the print is the result of variable ink
saturation and it is important to make sure that the heaters are
working correctly and that the heater settings are set to the right
temperature. Too hot and some media will ripple, too cool and the
ink will not dry.
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Banner
material doesn't feed properly
This is often due to the weight of the material roll causing
too much
resistance against
the friction feed of the printer.
To overcome this issue, which is more of a problem with some
older printers we
offer to rewind down 50m rolls to 2 rolls of 25m at no extra cost.
If this is not practical you can overcome this by manually unwinding
the required amount so that it feeds into the printer without
resistance.
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Blurred
image
Check
the original image file to make sure that the quality if high enough
for it to be printed at a high resolution.
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Colours
appear washed out
When printing onto transparent or translucent media for window
graphics
and backlit signs the colours can looked washed out. The best way to
overcome this is to overprint the graphics
again so doubling
up on the amount of ink and colour depth.
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Edge
curl after print & cut
This can be a problem on self adhesive materials if it is
contour cut
straight
after printing especially in darker coloured areas where there is the
most ink
output as the retained solvent from the ink causes the vinyl to soften.
Either select a thicker vinyl such as Xerox D-Jet 100 or D-Jet 200 as these have a
heavier face film and this reduces the likelihood of lifting or allow
24 hours for
the ink to dry before countour cutting.
Do not cut into the printed image as heavy concentrations of
eco solvent ink will
contribute to shrinkage and edge curl. Instead leave a 5mm border
around the image
and always conduct a suitability test.
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Flecks
appearing in the print
This is caused by dust or debris contamination from the print
room environment.
The inks tends to either accumulate around this settled debris and so
appears as
a dark fleck
or disperses around the debris and appears as an
unprinted white dot. Either way
it
is important to clean the area thoroughly and dry wipe the
roll using a clean lint free cloth
before trying again.
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Image
appears pixelated or blurred
The reason for this is generally the quality of the original
file source or the
editing of the file. It is important to ensure that the resolution
of the original file is of a quality high enough to give satisfactory
results.
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Ink
pooling during printing
Caused when too much ink is put down by the printer and shows up as
damp looking areas of colour and is especially noticable on gloss
surfaces. Check that the correct profile has been used and that the
heaters are functioning properly. Also, make sure that the roll
of media is at room temperature as cold rolls can exagerate the issue.
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Laminating Film Problems
It is important to wait 48 hours before laminating your prints to
allow the solvents in the inks to gas off. Failure to do this may
result in excessive laminate shrinkage or delamination as excess
solvents can break down the adhesive structure. Note that some
pale colours may look different when laminated but there is no way
around this.
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Uneven
colour when printing
More apparent when printing light pastel colours, the effect
being a
slight noticeable difference
of colour across the width of the roll. The easiest way to
prevent this happenning is to print
using the uni-directional mode.
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Vinyl
not releasing from its backing liner
It is sometimes easy to assume that the application tape is
too low tack to remove
the cut and weeded text / graphics however this rarely the case.
More often than not the reason for this problem comes down to
excessive cutting blade
pressure, which scores into the backing liner. The best way of checking
is by peeling
back some cut graphics and checking that the blade has only just marked
the backing liner
and that there is no scoring into the liner. Now check the reverse of
the backing liner
to check there are no visible impressions of the cut path coming
through.
If this is visible you need to reduce the cutting pressure
incrementally and produce a
number of test cuts to acheive the optimum pressure. Once this has been
done the graphics
should lift away easily.
The best method of removal instead of pulling the application
tape away from the surface
of the graphics is to turn the graphics over and remove the backing
liner away from the adhesive side.
Please note that each type of material will require you to
perform this test cut routine to
ensure optimum cutting pressure. Thicker materials such as fluorescents
and reflectives
as well as some polyester films generally require greater pressure than
standard vinyls
while thinner materials such as cast vinyls will require less pressure.
It may also be
neccessary to change the cutting blade for one with a greater angle for
sandblast
vinyls, reflectives and fluorescents as well as flock materials.
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Vinyl
peeling, cracking or edge lifting
The most important factor here is selecting the most suitable
film for the
job and remembering that although cast vinyl can be worked into
channels
and recesses as well as around compound curves using heat calenderd
vinyl should
applied onto these areas without putting the film under any
stress.
It is important to promote the initial adhesive contact to
ensure that graphics
do not lift or peel. Surfaces should be cleaned, dried and wiped with
Isopropyl
alcohol before any graphics are applied. In cold conditions it is best
to apply
heat after application to further enhance the bond.
When applying lettering to the sides of tankers and other
vehicles transporting
aggresive liquids such as fuel or solvents we advise that the edges
should be
sealed with a protective varnish.
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Vinyl
tunnelling or rippling
This is noticable at the point of printing when the vinyl ripples or
seperates from the liner and a 'tunnel'
appears
at the edge of the roll and works its way towards the centre of the
roll. It is caused by the heat of the printer being set too high, often
done to speed up the ink drying process. This excess heat caused the
face
film to expand on the relase liner resulting in
delamination.
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Watermark
appears during printing
This effect is noticed towards each end of the media roll and
may be
due to the fact that the roll has been left resting on the
printers feeder rollers for some time, perhaps overnight. The weight of
the roll
resting on the support
rollers
for this long period causes pressure through the roll and when
printed
the uneven surface causes this random effect. When not in use the
rolls of media should be stored vertically on end or in a properly
supportive carton as this can cause the same effect.
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