Why is anilox roll cleaning important in flexographic printing?

In flexographic printing, the anilox roll is responsible for accurately transferring ink, and its condition directly affects the quality of printing. Anilox roll cleaning is a key maintenance measure to maintain the good performance of the anilox roll. During the printing process, ink components like pigments, resins, and solvents accumulate in the anilox roll's holes. If not cleaned, these deposits change the shape and volume of ink cells, affecting ink storage and transfer, which can lead to problems such as uneven ink color, dot loss, and blurred lines in printed patterns.

What are the common types of deposits on an anilox roll and their effects?

There are three common types of deposits. Firstly, dried ink residues. After the solvent in the ink evaporates, pigments and resins dry and adhere to the anilox roll's surface and ink cells, reducing the effective volume of ink cells, decreasing ink transfer, and causing uneven ink transfer. When accumulated, it can form a hard shell, hindering ink transfer and causing mottled ink color in solid color patches. Secondly, impurities like paper shavings and fibers. If the substrate is paper, paper shavings may fall off, and fibers from ink or fountain solution can adhere. These impurities interfere with ink flow in ink cells, may scratch the anilox roll surface, affect its lifespan, and form defects like small white spots in patterns. Thirdly, deposits from chemical reactions. Some inks react with anilox roll materials or cleaning solvents, generating complex deposits that are hard to remove. They change the anilox roll's surface properties and roughness, affecting ink transfer and reducing printed product quality, such as causing color deviation.

What are the common cleaning methods for anilox rolls?

There are three main cleaning methods. The solvent cleaning method is commonly used. Select the appropriate solvent according to the ink type (water-based for water-based inks, organic solvents for solvent-based inks). Immerse the anilox roll in the solvent to dissolve or soften deposits, then scrub with a soft brush or a special cleaning brush, and control the immersion time to avoid excessive corrosion. The ultrasonic cleaning method uses the cavitation effect of ultrasonic waves in liquid to make deposits fall off. Place the anilox roll in an ultrasonic cleaning tank with cleaning solution, and set appropriate cleaning time and power based on the anilox roll's pollution degree and size. The high-pressure water jet cleaning method pressurizes water with a high-pressure water pump to form a high-speed water jet that peels off deposits. This method is fast and environmentally friendly as it mainly uses water as the cleaning medium.

Anilox Roll Cleaning: quality assurance for flexo printing

Date: Apr 07 2025 From: Star Color

In the process of flexographic printing, the anilox roll plays a crucial role in accurately transferring ink, and its condition directly affects the quality of printing. Anilox roll cleaning is a key maintenance measure to maintain the good performance of the anilox roll and ensure stable printing quality.
During the printing process, components such as pigments, resins, and solvents in the ink will gradually accumulate in the holes of the anilox roll. If not cleaned for a long time, these deposits will gradually change the original shape and volume of the ink cells. Once the ink cells are blocked or partially blocked, the storage and transfer volume of the ink will be affected, resulting in problems such as uneven ink color, dot loss, and blurred lines in the printed patterns.

Types of Common Deposits and Their Effects

Dried Ink Residues

After the solvent in the ink evaporates, components such as pigments and resins will dry and adhere to the surface of the anilox roll and inside the ink cells. This not only reduces the effective volume of the ink cells and decreases the ink transfer amount but also may lead to uneven ink transfer. When the dried residues accumulate to a certain extent, they will cover the anilox roll like a hard shell, seriously hindering the normal transfer of ink. When printing solid color patches, it is easy to have the phenomenon of mottled ink color.

Impurities like Paper Shavings and Fibers

If the printing substrate is paper, paper shavings may fall off during the printing process. If the ink or fountain solution contains impurities, fibers and other substances in them will also adhere to the anilox roll. These impurities will interfere with the flow of ink in the ink cells and may even scratch the surface of the anilox roll, affecting the service life of the anilox roll. Moreover, during the printing process, it is easy to form defects in the patterns, such as small white spots.

Deposits from Chemical Reactions

Certain inks may undergo chemical reactions with the materials of the anilox roll or the cleaning solvents, generating new deposits. These deposits have complex properties and are difficult to remove. They will change the chemical properties and roughness of the surface of the anilox roll, further affecting the ink transfer effect and reducing the quality of printed products, such as causing color deviation.
Printing machine mesh roller

A Comprehensive Analysis of Cleaning Methods

Solvent Cleaning Method

This is one of the commonly used methods. Select the appropriate solvent according to the type of ink. For example, for water-based inks, water-based cleaning agents can be selected; for solvent-based inks, the corresponding organic solvents should be used. Immerse the anilox roll in the solvent for a certain period to dissolve or soften the deposits with the solvent, and then use a soft brush or a special anilox roll cleaning brush for scrubbing. During the operation, pay attention to controlling the immersion time to avoid excessive corrosion of the anilox roll by the solvent.

Ultrasonic Cleaning Method

Utilize the cavitation effect generated by ultrasonic waves in the liquid to make the deposits on the surface of the anilox roll and inside the ink cells fall off under strong impact. Place the anilox roll in an ultrasonic cleaning tank filled with cleaning solution, turn on the ultrasonic equipment, and generally set an appropriate cleaning time and power according to the pollution degree and size of the anilox roll.

High-pressure Water Jet Cleaning Method

Pressurize water to a certain extent through a high-pressure water pump to form a high-speed water jet that impacts the surface of the anilox roll. The powerful impact force of the water jet can peel off the deposits. This method has a fast cleaning speed and is relatively environmentally friendly because water is mainly used as the cleaning medium.

Anilox Roll Cleaning: quality assurance for flexo printing

Types of Common Deposits and Their Effects

A Comprehensive Analysis of Cleaning Methods

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