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Beyond volume: how laser cleaning optimises anilox surface condition for consistent flexo quality


By Martin de Wit, CEO and founder, Laserclean I


n flexographic printing, anilox cleanliness is often treated as a maintenance issue. However, it is fundamental to assuring consistent print quality, production efficiency and workflow stability.


‘Deep’ anilox cleaning, which manufacturers recommend should be conducted every two to four weeks, is necessary because the cells get clogged with ink, residues and polymers. It is often evaluated by effectiveness of cell volume recovery. If a roll measures close to its specified volume, it is generally considered ready for production.


This is a costly assumption, though. Consider a scenario where a recently cleaned anilox roll returns to press with volume restored, but colour density still drifts. Operators intervene and ink formulations are adjusted. Time is lost, waste increases and process control becomes more difficult.


If the print performance is unpredictable,


even though the cell volume has been restored, this can be a sign that the anilox roller’s surface energy has been altered due to contamination. Surface energy describes how easily a liquid spreads across a solid surface. A simple way to visualise this is to compare water on clean glass versus water on a waxed car. On clean glass, the water spreads evenly because the surface energy is high. On wax, it forms droplets because the surface energy is lower. Ink behaves in the same way during printing. In flexography, surface energy plays a critical role in determining whether ink transfers cleanly and consistently. For effective transfer, the surface energy must progressively increase at each stage of the process - from the ink, to the anilox, to the plate and finally to the substrate.


In ideal conditions, the anilox both accepts ink consistently into its cells and releases it cleanly and uniformly onto the plate.


Figure 1: Eff ective ink transfer in fl exography depends on the progressive increase in surface energy, from ink to substrate


Over time, however, contamination interferes with this ink transfer ‘mechanism’: residues from inks, coatings and polymer particles from the printing plate accumulate within the cells. Where polymer builds up, the surface energy of the anilox raises - approaching the plate’s surface energy level - disrupting the wetting and release behaviour of the ink. As a result, cells fill and empty inconsistently, making ink transfer less stable and unpredictable. In practice, this can cause drifting colour density and inconsistent solids. Without a system for correcting anilox surface energy, printers may respond by making on-press corrections such as increasing pigment concentration or raising doctor blade pressure.


THE COST OF COMPENSATION While effective in the short term, these adjustments introduce cost and complexity. Even small increases in pigment usage (typically three to five per cent) can lead to significant volume, and thus cost, increases over time. Adjusting ink recipes adds time to an already complex process, increasing the risk of bottlenecks and reducing overall equipment effectiveness (OEE). Additionally, in regulated markets such as food and pharmaceuticals, manual recipe adjustments make traceability more difficult. Colour preparation becomes dependent on operator experience rather than controlled process conditions, even if ink kitchens are automated with dispensing systems. Quality becomes ‘guesswork’ - the antithesis of Lean production.


And while increased doctor blade pressure may improve ink transfer temporarily, it accelerates wear on both the blade and the anilox, increasing maintenance costs.


REMOVING RESIDUES AT MICROSCOPIC LEVEL


Compensating on-the-job is therefore not a sustainable strategy: to ensure repeatable quality and a simplified, automated workflow, it’s imperative to eliminate the source of any problem. With respect to the cell, it means the


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July/August 2026


www.convertermag.com


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