Anilox Roller the Heart of a Flexographic

 

The Anilox Roller, also known as the heart of a flexographic press, is frequently referred to. It delivers a consistent and precise amount of ink to each printing plate.

Anilox Roller is a hard cylindrical made of steel or aluminum. The anilox roller's surface is covered with a ceramic that contains millions of tiny dimples known as cells. We recommend different cell volumes and engravings depending on the type of printing. For a perfect printing result, it is crucial to choose the right anilox roller.

An incorrect anilox roller can cause problems for flexographic printers. This article aims to shed some light on this important topic.

Anilox roller

An anilox roll is the heart of the Flexo printing/coating process. It is a metering roller that is used to accurately transfer liquid ink, varnish, or coating onto an image carrier. The precise laser engraving of ceramic coated steel rolls has replaced the old mechanical methods of engraving cells onto the surface of a roll. This process involves drilling millions of tiny holes (cells), into the ceramic roll's surface. The anilox roll's ink receptivity, releasing and ability to absorb ink are of greater importance. Ink transfer abilities of the plate are determined based on the plate's surface technology, surface tension of ink and plate-to-ink compatibility.

The anilox roller is the central component of the press. This unique ink metering system allows for the right amount of ink to reach the printing plate. The cells that act as ink carriers are etched on the anilox roll's surface. The cells' size, shape, and number are determined by the manufacturer.Cell CountThe surface requirements (e.g. ) depend on:

• Ink used.
• Transfer amount
• Material to be printed.
• Image to be printed
• Configuration of ink trains

Laser engraving is used to create the latest anilox rolls. These are coated with fine ceramic and have cell counts up to 500 cells/cm. The laser-engraved ceramic rolls could last for up to 10 years depending on how much wear they get from the doctor blade. They deliver consistent, even ink delivery and offer narrow web flexibility. This gives them a competitive edge in leading packaging markets such as wine labels that are self adhesive. After the anilox has been 'charged with' ink, excess is removed with a flexible steel doctor knife.

Ink release abilities of cells are affected by more than just cell geometry. These include viscosity, surface tension and printing pressure between the impression cylinder and plate cylinder.

Anilox engraving angles

Anilox rolls have the following engraving angles: 90° angle, 45° angle, 30° angle, 60° angle and 30° angle.

The hexagonal cell has 15% more cells per square area at 60 degrees anilox angle. A higher number of cells is a sign that ink transfer and homogeneity are better.

Fiber optics laser engraving anilox roller:

• High-line engraving is possible with diode-pumped fiber optic lasers. High line engraving of screen was previously possible only with YAG (Yttrium Aluminum Garnet), lasers. It has excellent ink release properties and a durable cell structure.
• They have a very smooth structure and a solid structure. According to reports, the cells release ink 10 to 15% more than YAG engraving with the same line screen size and volume. High line screen rolls improve ink control and decrease dot gain. High line screens have made flexo more competitive with gravure and offset. It's very consistent and easy-to-maintenance.

Anilox Cell's Ink Releasing Capabilities:

Anilox Roller Characteristics:

• Angle Of The CellsThe 60deg Hex pattern is the standard worldwide for flexography printing. This is because the cells can be nested closer together, which allows for about 15% more cells per area.
• Anilox Roll Volume The area of the engraved surface per square inch is expressed in Billion Cubic microns.A higher volume means a higher solid ink density, a greater color range or a thicker coating. Ink films with thinner volumes are directly related to higher quality print and better process efficiency.
• Line ScreenThe third important component when specifying anilox rolls is line screen. It refers to the number of cells per inch. Anilox volume is directly related to line screen.

Anilox Roll Cell Terms

Anilox sleeves

• Today's narrow web presses are servo-driven and use anilox sleeves. These sleeves are lighter than standard anilox. This allows for easy handling and loading. The performance of the narrow web side is comparable to a standard roll. Initial anilox sleeves were designed for short-run environments in which anilox changes are frequent and necessary. However, they have proven their value regardless of how often they are changed. Sleeves are easy to store and manage.
• Sleeves have disadvantages. They are expensive and require special care. Sleeves cannot be cleaned the same way as rolls. This can lead to additional time and costs.

Anilox Inventory:

• Anilox rolls are a key component in the production of saleable products. Standardization of anilox rolls inventory can increase profits. Many times, 30+ rolls are seen in a pressroom. This not only ties up money but can also be confusing if the proper documentation isn't attached to each roll.
• It is essential to be able identify and inventory the minimum number of anilox rolls required for printing. This inventory can then be standardized across the pressroom to ensure greater consistency and profitability.

Enhancement of print quality:

• Fiber optic laser engraving anilox roll
• Anilox roll treated with ions-plasma to reduce wetting from working liquids and increase wear and corrosion resistance
• For smaller presses, a single reverse angle blade system is used. An enclosed doctor blade system is used for medium and large presses. A thinner blade edge will allow for a more thorough wipe.
• Composite blade materials and plastic doctor blades are more common in today's pressroom due to their safety advantages over metal blades. Plastic blades are more prone to contamination from the printing process.
• Laser engraved ceramic anilox rolls, chambered doctor blades and UV coatings are all effective in metering inks. The application is consistent, precise and uniform. All voids, thickness variations and slinging are eliminated.
• Right elastomeric compound roll covering with chemical resistance, ink transfer qualities and hardness.
• Digitally-imaged rolls, sleeves, and plates improve print quality, reduce set-up and make ready time, and increase press speed.
• Modern flexo presses have heating, cooling, and conditioning control systems. They are equipped with integrated automatic controls, drives, and functions to handle temperature problems. This reduces wastage and improves print quality.

Recent Developments

• Digital ImagingHalf tone work can be done on plates with very high quality.
• Sleeve Technology-The entire printing plate was produced using a removable sleeve attached to the printing cylinder. This allows for faster presses and better registration.
• Water-based InksYou can use them which are more sustainable. Water-based inks can be used in the same way as solvent-based inks. They require the evaporation water to create the final printed result. This means that drying takes more energy via heat. As an environmentally-friendly printing method, water-based inks are actively encouraged. Water-based inks have become more popular in the paper and corrugated industries. The water is absorbed into substrate, which reduces the amount of energy needed to dry ink completely.
• UV Curing InksThey are ideal for narrow web label and carton board applications because they have high resolution, strong colours, and easy to handle. These inks are made from finer anilox rolls with a lower ink volume.
• Gearless PressesYou can make infinite adjustments to the repeat lengths.
• Microdot Mounting SystemsExcellent registration

Conclusion

Flexo packaging is the future, and digital is the future. Digital technology can be used throughout the packaging process to provide benefits for consumers, from concept to customer, such as speed, color management and consistency.

Flexography is a cutting-edge printing process that has made itself a name for itself in the packaging and label printing industry. It offers high quality, cost-effective inline printing, and can be used to convert everything, from short runs to long runs on paper, film, or board. Flexography is the future of industry because it is the most versatile printing process.

Flexography is becoming more automated and capable of producing zero defects products at a lower cost. This is not what the future holds, but it's what flexography has in store for the future.