Screen Printing - June/July 2017 - 21

New entrants in direct-to-object printing include companies with long histories in analog printing, including Heidelberg's Omnifire 1000 (left) and
Hinterkopf D240 (right), machines designed for production-length manufacturing applications. Courtesy of Heidelberg and Hinterkopf, respectively.

BREAKING DOWN TECHNOLOGY BARRIERS
The increasing adoption of inkjet technology for product
decoration demonstrates the market's acceptance that it's a
reliable technology capable of being used not only in small
systems, but also implemented in true industrial environments - even in high-throughput, 24/7 manufacturing lines.
Achieving this level of reliability and robustness is the result
of many years of innovative system design, process development, advances in ink formulations and curing technologies,
and data processing software to enable variable-data printing
at high speed and high resolution.
Inkjet inks (typically UV LED-curable) must adhere to
a wide range of substrates including glass, metal, and a
multitude of plastics. Different substrates require different
pretreatment processes such as alcohol, flame, plasma,
corona, or coating primers. Post-print varnishes and protective top coatings may also be needed. System developers
are beginning to incorporate these processes. For example,
the Xjet from Inkcups Now offers the DigiBond Primer for
printing onto metal; Apex Machine provides an optional
inline pretreatment station for their DB1000 and DRT2000
Digital systems; and Engineered Printing Solutions (EPS)
offers pretreatment and vision system options for its XD070
and XD060 systems.
Certain substrates benefit from a base coat of white ink to
make the overprinted colors brighter, but matching the opacity of a screen printed white is a challenge for inkjet. Multiple
printheads or passes may be needed to jet an acceptable layer
of ink. Many system vendors now offer an optional white ink
station; in larger production systems, white is standard. However, an alternative to using inkjet for the white base coat is
to take a hybrid approach and combine the strength of screen
and inkjet technologies in a single line. This has been shown
by KBA-Kammann in its latest K20 series. The company has
taken the approach that the inkjet stations must fit within the
system architecture of its K20/K15 series screen printers, with

no loss of speed - so that, according to job requirements,
users can produce hybrid technology decorated products.
For example, they could use the screen stations for the white
precoat and spot colors and inkjet to print CMYK.
One of the often-cited benefits of inkjet is that it is a
noncontact technology. Industrial inkjet printheads have been
designed to print onto flat surfaces with an optimal throw
distance between the printhead and substrate of less than
1 millimeter for small drops. Such small drops decelerate
quickly as they travel to the surface; if the throw distance is
too great, then the drops may not land in the intended place
and image quality deteriorates. Larger drops can jet further
(up to approximately 5 millimeters), but compromise the
graphical image quality. Printers are finding they can mitigate
this through careful selection of images, using inkjet to
great effect to decorate objects with textured or contoured
surfaces where it would have been impossible to apply a
label. Krones, a major beverage machinery supplier, took this
approach when they launched the Decotype R at Drinktec in
2014. At the show, they printed shampoo bottles with shaped
surfaces, creating interesting visual and haptic effects that
not only replaced the label, but also surpassed it with effects
that would have otherwise been impossible. The technique
has been widely applauded: Cycling bottles from Krones won
a 2015-2016 A'Design Award, and the shampoo bottles were
awarded an Oscar dell'Imballaggio by the Italian Packaging
Institute in 2015.
We're also seeing more systems that can accommodate
larger or taller objects. The FJet XL from EPS, for example,
can take items up to 5.9 inches high; the Azon UV Matrix can
print on products up to 7.9 inches high; and Mimaki's UJF3024 HG (High Gap) unit can accommodate objects up to 5.9
inches high. German company Ritzi has the first installation
of the Heidelberg Omnifire 1000 to decorate large automotive
components, such as trim strips, switches, dashboards, and
other finished components as part of their production process.
JUNE/JULY 2017

Table of Contents for the Digital Edition of Screen Printing - June/July 2017