Operating Instructions
Machine Description
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ITS6_135_Manual_EN.doc
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4.6.17.1 Layout and function of the pre-curing unit
The ink applied by each of the first three print head rows is pre-cured by UV
light on its way to the next print head row to the point that an intact mem-
brane is formed on the surface which will not allow the mixing of any ink
applied later. The ink underneath this membrane has not cross-linked yet
and therefore remains fluid. Pre-cured ink cannot withstand chemical and
mechanical loads, and therefore can be washed off or smeared with little
effort.
After the fourth print head row (black), no more pre-curing takes place since
no more ink is applied, but rather, the printing substrate is conveyed to the
main curing module, where all of the applied ink is completely hardened.
Fig. 42. Close-up of a dismantled LED-strip of the pre-curing unit
All three of the UV pre-curing modules have the same design. The lamps
consist of UV LEDs which, compared to UV fluorescent tubes, do not have
to be pre-heated, and therefore require less energy. Due to the low heat
emission, even heat-s
ensitive materials won’t be damaged. The lamp mod-
ules of the UV pre-curing modules are water-cooled.
In case of activated UV pre-curing the associated LEDs are switched on
automatically before the uncured image reaches the first lamp module.
While the printing process is going on, all of the UV pre-curing modules re-
main switched on continuously. They are not switched off until the printing
process is stopped and the printing substrate is no longer moving forward.