When print quality falls short of expectations, attention often turns to the ink, the printing plates, or the press itself. Yet, in our experience, one of the components that most frequently determines the final result is the anilox roller. There is a reason why it is often referred to as the heart of the flexographic printing process.
Its task may seem straightforward: pick up a controlled amount of ink and transfer it to the printing plate. In reality, critical factors such as coverage, color density, image sharpness, solid ink laydown, and process repeatability all depend on this operation.
To the naked eye, the surface of an anilox roll appears almost perfectly uniform. Under magnification, however, it reveals a structure composed of millions of microscopic cells. Each cell has dimensions measured in just a few hundredths of a millimeter, both in diameter and depth, and is designed to hold and transfer a specific volume of ink. A significant portion of print quality is determined by what happens inside these microscopic cells.
That is why one of the most important questions to ask is: what combination of line screen and cell volume is actually right for my application?
Line Screen and Cell Volume: more than just numbers
People approaching anilox technology for the first time often focus exclusively on the values listed in technical specifications. In practice, line screen and cell volume are much more than numbers on a data sheet:
- Line screen: refers to the number of cells contained within a given surface area of the roll. As line screen increases, the number of cells increases as well, while their dimensions generally become smaller.
- Cell volume: represents the amount of ink the roll can carry and transfer during the printing process.
The two parameters are closely related, but they are not interchangeable. Over the years, we have seen anilox rolls with very similar line screens behave quite differently on press. The reason is simple: actual performance depends not only on the number of cells, but also on their geometry and on how efficiently they release ink to the printing plate. This is one of the reasons why anilox selection remains both fascinating and challenging.
Ink is always the starting point
Every ink formulation brings its own characteristics to the printing process:
- Highly fluid inks tend to spread easily on the substrate and generally require very precise control of ink deposition.
- Conversely, when working with more viscous inks or specialty formulations, greater transfer capacity may be necessary to achieve the desired coverage and color strength.
There is no universal rule that applies to every situation. Each combination of ink, printing plate, substrate, and press speed creates its own operating conditions, and those conditions should always be evaluated as a complete system. This is precisely why selecting an anilox roll should never be treated as a simple catalog exercise.
The substrate plays Its part too
Another factor that is sometimes underestimated is the behavior of the substrate itself. Plastic films, paper, nonwoven materials, and technical substrates all react differently to the same amount of transferred ink.
- On a non-absorbent plastic film, for example, maintaining tight control of ink laydown is often the primary objective in order to avoid unwanted ink build-up.
- On highly absorbent paper grades, part of the ink is inevitably absorbed into the material, which may require a different transfer volume to achieve the desired visual result.
Then there are the truly demanding applications:
- Nonwoven materials, embossed substrates, meshes, and irregular surfaces often require a combination that is difficult to achieve simultaneously: high coverage, excellent uniformity, and strong image definition.
In real production environments, these are often the applications that truly reveal the strengths and weaknesses of an anilox roll.
The graphic design changes the rules
The type of image being printed deserves just as much attention as the ink and substrate. A job consisting primarily of fine text and intricate details has very different requirements from one dominated by large solid areas. Screens, gradients, and tonal transitions introduce additional variables.
In these situations, the objective is not simply to transfer more ink or less ink. The objective is to transfer the right amount of ink in the right way. When looking at an excellent print result, it is easy to credit the press or the printing plate. Very often, however, the quality of the final image is the result of a carefully balanced relationship between artwork, substrate, ink, and anilox roll.
The perfect Anilox Roll does not exist
One of the questions we hear most often is: “What is the best anilox roll?“
Our answer is usually another question: “For which application?“
Over the years, we have seen outstanding anilox rolls deliver disappointing results simply because they were selected for a job they were never intended to run. Every printing application is a balance between multiple variables: ink, substrate, production speed, coverage requirements, plate quality, and image characteristics. That complexity is what makes it so difficult to identify a universal solution. It is also why nominal line screen and cell volume values never tell the entire story.
Cellox™: developed through real-world applications
Over the years, we have worked on some particularly demanding applications. Technical materials, nonwoven substrates, challenging surfaces, and specialty inks have often exposed limitations that could not be fully explained by line screen and nominal cell volume alone. As we studied these situations more closely, it became clear that a significant part of an anilox roll’s performance depends on how efficiently its cells release ink.
That observation ultimately led to the development of Cellox™, the proprietary anilox roll technology used on our Miniflex® flexographic printing presses.
Its optimized cell geometry was specifically designed to improve ink transfer efficiency and deliver:
- Greater print uniformity;
- Improved color saturation;
- Enhanced coverage on difficult substrates;
- Stability during long production runs;
- Excellent repeatability.
Cellox™ has proven particularly effective in applications involving nonwoven materials, technical substrates, challenging surfaces, and specialty inks, where conventional expectations based solely on nominal line screen and cell volume do not always tell the whole story.
Measurable performance and certified quality
When it comes to anilox rolls, quality should never rely solely on manufacturer claims. That is why every Cellox™ roll is supplied with a Giugni® Certification Label generated through measurements performed using the CellMeter™ inspection system.
The certification documents the roll’s key technical characteristics and allows its performance to be monitored over time. For printers, this means greater process control, improved repeatability, and a more effective approach to print quality management.
An efficient Anilox Roll is also a clean Anilox Roll
There is one final aspect that is always worth mentioning. Even the highest-performing anilox roll available on the market can gradually lose efficiency if its microscopic cells are not kept perfectly clean. Ink residues and contaminants can reduce the effective transfer volume and alter the roll’s behavior compared to its original condition. For this reason, cleaning and maintenance should never be considered secondary activities. They are an integral part of proper anilox management.
After decades of experience in flexographic printing, we still consider the anilox roll one of the most fascinating components of the entire process. Its physical dimensions are relatively small, yet its influence on print quality is enormous. That is probably why selecting the right anilox roll remains, even today, one of the most important decisions for anyone seeking to get the very best performance from their flexographic printing press.
Written by Sergio G. | Team Giugni®
