How to Use and Clean Anilox Rollers

This article analyzes the problems faced in the purchase and use of anilox rollers, and proposes how to order anilox rollers with the correct line number and ink volume. It also proposes that standardizing the management of anilox rollers can bring considerable cost savings to printing companies. Maximize the value of the anilox roller.

As the core of flexo printing, the anilox roller has attracted much attention, but we seem to be more concerned about its investment. An eight-color satellite printing press that uses solvent-based inks to produce flexible packaging. To meet normal production needs, 12 to 16 anilox rollers (including spare rollers) are required. It requires an investment of 300,000 to 400,000 yuan (excluding tax).

According to printing industry survey data, the high cost of anilox rollers is one of the biggest concerns for factories and has become one of the reasons hindering the development of flexo printing.

But in practical applications, we need to think about it, do we really use the value of the anilox roller?

1、 Problems faced in purchasing anilox rollers

Looking at the anilox roller in terms of price, it is very expensive! However, investors are only responsible for buying. They feel distressed when buying, but how to use it after buying it? How to use? There is no detailed tracking.

Due to insufficient understanding of anilox rollers and flexographic printing, during the purchase process of anilox rollers, the impact of the matching of anilox roller line number and ink volume on actual production is often overlooked. Causes various problems in subsequent use and brings huge waste.

Users ignore its price in specific applications, do not have strict and scientific operation manuals, lack effective management of anilox rollers, or even have no management at all, resulting in most anilox rollers not reaching the theoretical lifespan. It completely fails to reflect the value of the anilox roller as the core of flexo printing.

These factors appear again and again, putting huge pressure on flexo printing investors and seriously hindering the development of flexo printing.

Investors must first have a very clear understanding of flexographic printing and anilox rollers. As the "heart" of flexographic printing, the anilox roller is actually a metering roller that accurately delivers the required ink to the printing plate ( As shown in Figure 1, the ink is transferred from A to B),

Then it is transferred from the printing plate to the substrate (as shown in Figure 1, the ink is transferred from B to C);

Ink storage, ink distribution and ink transfer are its three major functions.

Ink transfer is its ultimate performance. Without it, flexographic printing cannot be completed. The anilox roller has such a core value and the price will definitely not be cheap.

Figure 1  Ink transfer from anilox roller

But is the anilox roller really a major cost increase for printing companies? the answer is negative.

The normal service life of anilox rollers is 2 to 3 years, and they are usually updated after two years, ranging from 2 to 6 units per year. Through the cost sharing calculation of massive orders in the flexo printing production process, it will be found that the investment in anilox rollers and the cost sharing in the flexo printing production process are very low.

At the same time, we should also see that compared to gravure printing, flexographic printing consumes less ink and has better color consistency. This is the advantage of flexographic printing, and this advantage is the value of the anilox roller.

Therefore, investors must have an overall understanding of flexo printing. Flexo printing is a work process that requires balance in all aspects. The anilox roller is the fulcrum of this balance and an important part of flexographic printing production. It has high value and High price and long life. Investors should not treat it as a consumable, but should allocate the cost of the value it creates from the beginning of use to the final scrap, so that the pressure will be much less.

The value of a high-quality anilox roller far exceeds the price difference of a low-quality anilox roller. As shown in Figure 2, the cells of different quality anilox rollers vary greatly.

Figure 2  Cell performance of anilox rollers of different qualities

2、 How to order anilox rollers

When ordering anilox rollers, you need to choose the appropriate number of lines and ink load.

The value of the anilox roller comes from the controlled transfer of ink; the line number of the anilox roller is closely related to the ink capacity. The higher the line number, the lower the ink load and the smaller the ink transfer; The lower the line count, the higher the ink load and the more ink will transfer.

As shown in Figure 3, different printing requirements require different ink loading volumes. It should be noted that depending on the type of ink used and the type of substrate, anilox rollers with the same number of lines have different ink loading requirements.

Figure 3  The influence of line number and ink load on printing

Therefore, when ordering new equipment, the selection should be based on the existing order situation and the order structure after entering the flexo printing market. For specific information, you can consult a professional anilox roller supplier, which can avoid selection errors that will lead to incompatibility in subsequent production and cause huge waste.

In the process of updating anilox rollers, it is necessary to understand the current market development. For example, when a 120LPI printing plate was originally used, an 800LPI anilox roller was configured; now that the market has further developed towards high-definition printing, the line number of the printing plate will gradually be upgraded to 133LPI or even 150LPI. If you are reconfiguring an anilox roller for printing four colors, check the corresponding relationship between the anilox roller line number and the printing plate line number as shown in Table 1. In order to ensure that the diameter of the smallest dot on the printing plate is larger than the anilox roller cell opening, you should decisively upgrade to an anilox roller of 1000LPI at this time.

This avoids the problem of needing to reorder due to failure to meet requirements.

Generally speaking, the higher the line count of the anilox roller, the higher the clarity of the printed image, as shown in Figure 4. With the development of anilox roller technology, anilox rollers with higher line counts can achieve better ink transfer and ensure solid density needs. High thread count and high transfer are the requirements that high-quality anilox rollers must meet.

Figure 4  Printing performance of anilox rollers with different line numbers

Flexo printing is developing very fast, and printing plates with high color strength, low viscosity inks, flat tops and surface textures are becoming more and more popular. If we still rely on previous experience values and do not have a new understanding of the ink capacity of the anilox roller, we will encounter more problems in production, such as dirty plates, blocked plates, etc.

We should promptly adjust the requirements for the ink load of the anilox roller during the anilox roller update process to ensure stable production.

Choosing the correct line number and ink load will bring huge savings in ink consumption, which is often ignored by printing factories;

Because of the anilox roller with the ink load capacity ordered, the ink consumption has been basically determined. If there is no long-term use comparison of the new ink load anilox roller, there is no way to know the difference.

We need to remember this law: when a high-line-count anilox roller can achieve the same printing solid density as a low-line-count anilox roller, a high-line-count anilox roller must be selected for production. For example, if a 900LPI anilox roller can achieve a solid density of 800LPI, a 600LPI anilox roller can meet the spot color printing requirements of 500LPI, and a 400LPI anilox roller can meet the background color printing and varnishing requirements of 360LPI;

We choose 900LPI, 600LPI and 400LPI anilox rollers with higher thread counts, which can save about 5% of ink compared to the original corresponding 800LPI, 500LPI and 360LPI choices;

At the same time, it can bring about a more stable production process and reduce the time of downtime and plate wiping. These savings are net profits, which far exceed the increased investment cost when you purchase high-quality, high-thread-count anilox rollers.

Therefore, according to the actual needs of the printing enterprise, before ordering and upgrading anilox rollers, it is very important to select the correct number of lines and ink load of anilox rollers. This is not only the key to avoiding repeated investment, but also the basis for stable production of the company in the future.

3、 How to make good use of anilox rollers

The use of anilox rollers currently encounters many problems, which seriously restricts the value of anilox rollers.

At present, there are three main problems in the use of anilox rollers:

1. Irregular operation

The problems caused by irregular operation are collision damage (as shown in Figure 5), ovality changes and scribing on the surface of the anilox roller (as shown in Figure 6).

Figure 5  Edge damage caused by collision

Figure 6  Anilox roller surface markin

2. Anilox roller management chaos

The problems caused by chaotic anilox roller management are poor printing reproducibility, increased number of downtimes and difficulty in achieving production traceability.

As shown in Figure 7, for a 6.7cm3/m2 anilox roller, the initial printed solid density of red is 1.35. After a period of use, due to wear or a certain degree of clogging, the printed solid density of the same ink becomes only 1.10. The trouble it caused to production was obvious.

Figure 7  Changes in ink volume during use of anilox roller

3. Irregular cleaning

The problems caused by irregular cleaning are corrosion of the anilox roller body (as shown in Figure 8), Anilox roller texture blocked (as shown in Figure 9) and waste of ink.

Figure 8 corrosion

Figure 9 Anilox roller texture blocked

For the problem of anilox roller cleaning, the current best solution is to use anilox roller laser cleaning machine.

Laser cleaning can penetrate into meshes of any shape and size, especially suitable for high-line count anilox rollers. It can realize the recovery of cell volume without damaging the mesh wall, no consumables and no pollution, and the vaporized ink can aiso be recycled, which can extend the service life of the anilox roller and is low-carbon and environmentally friendly.

Compared to traditional chemical cleaning, it saves the cost of consumables and labors, which can save a lot of costs for enterprises in the long run. Based on this, laser cleaning anilox rollers has gradually become the mainstream cleaning solutions.

Deep cleaning at least 1-2 times a year will restore the anilox roller as new. Prolong the service life of the anilox roller, improve printing quality, and reduce ink loss.

DOYA Laser is committed to providing professional cleaning solutions for ceramic rollers in the corrugated-, fiexo-, laber- and offset printing industry. After several rounds of upgrades, DOYA ceramic anilox laser cleaning machine has reached the technological level of the same type of products in Europe, filing the gap that China's anilox laser cleaning equipment relies on imports.

At present, two series of anilox roller laser cleaning equipments have been launched, one is the cabinet-type, and other is ACLM online cleaning equipment.

The Unmatched Printing Quality And Sustainability

All ALC machines have the same cleaning process: the roller is being driven and turns, while the laser gun is being moved from left to right, parallel to the dirty roller. The energy of the laser beam is absorbed by the pollution, which consists of pigments and polymers, and then disintegrates. The laser beam is enough powerful to remove the pollution but doesn't possess the power to damage the ceramic surface of the roller. After laser cleaning cell volume and surface tension are fully restored and the roller can be immediately used for printing.

Laser cleaning is the most controlled and efficient way to clean anilox surfaces, resulting in the highest constant printing quality.Laser cleaning is based on indirect contact the roler isn't touched other than by the laser beam, No granulates chemicals or water are needed.

ALC laser cleaning machines offer the most sustainable and environmental friendly cleaning method for anilox rollers.

The anilox laser cleaning machine becomes the standard equipment of the fiexo printing workshop, which is the mission and vision of DOYA.