Home' FLEXO Magazine : October 2014 Contents transferred from the plate to the substrate, creating elongated voids on
the final substrate between them as shown in Image 1.
It should be noted that not all of the ink supplied to the anilox roll is
transferred; in fact the common rule of thumb is that 50 percent of
the volume is transferred from the anilox to the plate, and 50 percent
is transferred from the plate to the substrate. This equates to approx-
imately 25 percent of the original anilox volume being transferred to
the substrate, but there are many press and component parameters
that can impact this percentage in production.
Throwing more ink at the pinholing does not solve the issue; more ink
simply drives up the consumables costs and requires more energy to dry
it. In fact, using more ink requires a higher volume anilox roll, but these
rolls often have lower lpi values with bigger cells and a larger gap between
the centers of each ink dot, resulting in potentially larger voids between
the ridges of ink. It’s a real dilemma for flexo print professionals.
There are several approaches today that are intended to eliminate or
reduce the negative effects of pinholing. One option is to reduce the
amount of gap between the anilox cells on the roll, which can increase
the ink flow but is limited in how far it can be adjusted. Another
option is, as mentioned before, to change the surface of the plate by
adding cells to carry more ink, but does that really just mask the issue
and drive up ink costs? The lowest ink consumption with a uniform
ink film will always deliver the highest density at the lowest cost.
A unique form of micro surface texturization, however, is able to over-
come pinholing and deliver the rich, smooth solids brand owners and
packaging professionals desire. Compared to traditional technologies
used to address pinholing, micro texturization is significantly smaller
and finer. Image 2 shows three areas of 70 percent coverage; the top
left is with no surface treatment applied, the bottom left is a tradition-
al application with cells in the surface of the plate and the right shows
micro texturization with DigiCap NX patterning.
Micro texturization produces a pattern on the surface of the plate—
like regular rectangular islands surrounded by a thin sea of ink—that
breaks up the cell pattern from the anilox roll on the surface of the
plate. Splitting the anilox pattern, divides the pinhole pattern and sig-
nificantly improves the ink transfer. Image 3 shows the printed solid
from a traditional flexo plate on the left and from a Flexcel NX Plate
using DigiCap NX Patterning on the right, using the same press, ink
and anilox on the same substrate.
Achieving better ink transfer yields a number of advantages, including
greater color gamuts, better print quality, higher print speeds and
greater consistency. Printers often are able to reduce the number of
anilox rolls and inks used while still achieving the densities and colors
required. Color gamuts are improved because the solids are clean,
rather than being pinholed and muddy, and when overprinting to
build extended gamut colors, the results are brighter.
The ability to build cleaner and brighter colors enables flexo printers to
do more of their work with process printing instead of relying on spot
colors. This improves a printer’s ability to standardize printing and ink
sets, even when engaging in 4- or 7-color process printing. By reducing
the number of colors and simplifying the print process, printers are able
to reduce costs for their clients and improve their overall bottom line. n
About the Author: Dr. Andreas Albat leads Kodak’s
worldwide packaging R&D activities including devel-
opment of the Flexcel NX and Flexcel Direct Systems
and works closely with the Unified Workflow Solutions
team on software solutions with focus on screening and
pattern development for packaging. With an extensive
background in color science, he is also responsible for the development
of Kodak’s Spotless Software and on going enhancements to Kodak’s
Approval proofing solution.
Kodak DigiCap NX Patterning uses a different approach to plate
surface patterning based on islands, not cells. It was added to the Flexcel
NX System as a standard component in 2010 to address the remaining
Achilles heel of flexo—solid ink densities compared to gravure printing.
Its implementation relies on the use of Kodak SQUAREspot Imaging. It is
built into all Flexcel NX Imagers, and enables the unique capability of the
Flexcel NX System to achieve 1:1 reproduction of very fine elements all the
way to the plate. DigiCap NX Patterning is applied to the 1-bitt TIFF file
as it is processed for the Flexcel NX Imager, so it does not increase RIPing
times and functions regardless of the workflow that created the file.
Image 2: Images showing plates with 70 percent dots, with no surface
texturization, traditional surface cells and DigiCap NX Patterning applied
Image 3: Comparative prints from a 100 percent solid patch, from the
same press, ink, anilox and substrate, using traditional digital flexo on
left, and Flexcel NX plate with DigiCap NX patterning on right
78 FLEXO | OCTOBER 2014
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