“HD Flexo is equal to exceptional quality”

Shrihari Rao of Esko-Graphics India, demystifies the technology, and tells Noel D’cunha that Esko’s HD Flexo is set to trigger the growing use of flexographic printing in the label segment.

09 Oct 2013 | By Noel D'Cunha

Labels requiring high quality have generally been printed using the offset process until recently. However, great advances have been made to the quality of flexographic printing presses (gearless drive - servo and combination press), printing plates (solvent, thermal and water washable  photopolymer plates) and printing inks (water-based, solvent-based and UV-curing inks).

“The greatest advances in flexographic printing have been in the areas of pre-press and platemaking (photopolymer printing plates), including improvements to the plate material and the method of plate creation (processing) and imaging technology (CDI),” says Shrihari Rao, sales director - South Asia, Esko-Graphics India. A Label flexographic press is capable of producing high quality impressions (solids =>mid tones => highlights) on many different substrates and is the least expensive and simplest of the printing processes used for decorating and packaging printing. Rao says, “The use of flexographic printing is on the rise, and Esko HD Flexo is set to drive it further.”
During the Labelexpo Europe 2013, Esko showcased the HD Flexo technology. Bengaluru-based VeePee Graphic Solutions has ordered the system and is set to become an early adopter of the technology in India. VeePee has been a loyal supporter of Esko, since it first installed an Esko kit ten years ago.
It’s a known fact that you need quality flexo printing plates to achieve exceptional flexo results. Today, there are products like Esko’s HD Flexo, which claims to deliver a new level of flexo quality. “It not only does that, it also reduces makeready time on the press and what’s more, HD Flexo printing plates deliver greater run lengths. And because they need fewer washing cycles, the press is optimally used.”
There is a sustainable benefit as well. “Printing flexible packaging on a flexo press instead of gravure reduces energy use and CO2 emissions by as much as 50%. Converters and brand owners can improve sustainability by taking advantage of the higher quality offered by this technology,” says Rao.
So, what is HD Flexo?
HD Flexo combines high resolution imaging at 4,000 ppi using high definition optics in the CDI with HD Flexo screening technology. “These are technologies developed by Esko and the result is excellent print quality and a simplified plate production,” says Rao. 
The high resolution optics deliver more natural gray levels, sharper imaging of text and lines; and a better definition of screening dots. Rao says, “HD Flexo is able to create a textured surface on the flexo plate or sleeve. This improves ink lay-down and increases ink density on the final print. This boosts image richness and contrast and is especially helpful for brand colours, and for white and spot colour printing.”
What is Full HD?
Full HD Flexo adds perfect ink laydown with the right solid density, vibrant brand colours, supreme platemaking consistency and the only fully digitally controlled platemaking workflow available in industry.
How does it work?
The Full HD Flexo technology combines high resolution imaging at 4,000ppi (HD Flexo imaging and screening technology) with digitally controlled main exposure inside the CDI. The digital Inline UV2 main exposure through an LED-array delivers a UV power density high enough to gain full control over the polymerization process during main exposure.
Rao says, “The Inline UV2 digital main exposure now makes flexo platemaking fully digital. Human errors are reduced and the plate consistency is boosted enormously.
“Controlling the dot shape, the unique Full HD Flexo platemaking process can digitally control the dot shape: Full HD Flexo plates and sleeves now combine the highlight capability of HD Flexo and the solid ink lay down capability and print stability of ‘flat top’ flexo plates.”

Evolution of Digital Fexo to Full HD Flexo
A leap forward
A major leap forward in flexo technology is digital plates with UV main exposure. Digital plates get UV main exposure in the same device in which they are imaged. This means that no subsequent exposure is required on an offline light frame. 
Rao explains, “Combining these two processes in one device brings down costs, reduces errors and boosts quality. The Inline UV main exposure option increases the quality and reliability of digital flexo plates by ensuring that each square centimetre of the plate receives the same amount of UV light needed to fully polymerize the plate. It reduces the operating costs and environmental load.”
The Esko CDI has an integrated, digitally controlled, ultraviolet diode array. With this UV technology the UV main exposure stops being an analogue process. “UV main exposure is now a highly precise and a digitally controlled process. This has the added advantage of eliminating an extra step in the workflow: the UV main exposure is done inline, after  the imaging of the flexo plate, without any operator intervention,” says Rao.
Inline UV advantages
Esko UV diode technology converts the UV main exposure from an uncontrollable analogue process to a high precision digital process. Rao says, “Esko’s digital Inline UV main exposure allows to choose the dotshape per plate or sleeve. With the Inline UV1 setup round top dots are created offering the known dot shape compatible with the use of bank light tables. Thanks to the digitally controlled process, the dots are of highest quality and of perfect consistency all over the plate.”
According to Rao, the Inline UV1 exposure delivers plates with the most stable and sharp round top dots. With the use of HD Flexo,these round top dots print gradients down to zero; they also deliver much improved solid ink areas with almost no pinholes, while the Inline UV2 setup in combination with advanced HD Flexo screening (equal to Full HD Flexo) creates a unique dot shape that delivers the best highlight quality in combination with perfect solid ink lay down in all flexible packaging applications. “Full HD Flexo also boosts corrugated printing due to fluting reduction. Furthermore, Full HD Flexo brings quality and consistency benefits to label printing by improving print consistency and highlight stability, and by reduction of gear marks.”
An alternative to gravure and offset?
With Full HD Flexo, will the gap between flexo and gravure and offset be closed? Rao believes so. “Bringing consistency, vibrant colours and increased print quality, Full HD Flexo raises the industry standard in flexo printing. Flexo printing can now compete with offset for quality labels and with gravure printing for flexible packaging.”

History - Flexo Innovation

For decades Esko has been developing software and hardware solutions for the packaging industry.The company invented digital flexo in 1995 and has been leading the development ever since - their products areused in about 90% of high quality flexo production. Today, Esko is synonymous with excellent quality and consistency in all flexo printing applications.
The showcase
At every show and at its demo centre in Bengaluru, Esko showcases flexo printed production produced by print companies across the world, including printer from China and India. The showcase has shrink sleeves, cartons, pouches, Tetrapak, labels and the entire gamut in flexo. All these are now a possibility with Esko workflow and HD Flexo imaging technology.