TIP: If you notice that one of the substrate edges is not as well tensioned as the other between the platen
and the main roller, showing a wave-like shape as it enters the platen, then you are likely to have skew, and
you should consider the use of the center support for dual-roll spindle in both input and output.
TIP: When suering from extreme skew that tends to increase (normally with highly temperature-sensitive
substrates), try to use a thicker core that is not deformed by the rubber traction grooves on the spindle when
inated. Then follow the guidelines below for reducing skew.
Generally, the main contributor to skew is an imprecise substrate load, and the eects of that are worse with
wide rolls. However, if you have some skew or telescoping but this does not aect your print quality, and does
not generate wrinkles in the substrate (see There are wrinkles and ink smears on the substrate on page 299),
there is no need to take any action. However, you are recommended to reload the substrate in order to
eliminate any potential problem.
Some substrate rolls already come with skew; in that case the recommendations are as follows:
1. Try to load the substrate following the correct procedure, taking as a reference of the roll’s width the
average between peaks of skew.
2. Start with the recommended conguration and increase vacuum and tensions step by step (i to iv),
following the table below.
There are wrinkles and ink smears on the substrate
W
rinkles in the substrate indicate that the substrate settings that control the substrate shape are not
optimized. This can cause various printing defects.
●
Colored bands in area lls in the vicinity of the wrinkles
●
Ink smears if the printhead touches the substrate
●
Cockle
●
A substrate crash if the printhead's movement over the substrate is impeded
There are various reasons why wrinkles and other consequent eects could appear while printing:
ENWW Printing issues 299
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