April 18, 2024

What is CI Flexo Press? A Comprehensive Guide for Beginners


Flexography has become the main player in the printing market, leaving behind other techniques in its wake by its versatility and efficiency. In the realm of different flexo presses – inline, stack, and central impression (CI) – the CI flexo press is the number one choice for a lot of businesses. It is a fan favorite because it can print high resolution and also it can handle any kind of material. Its secret is the central impression cylinder, which ensures that all the colors match up perfectly. That’s why it is an essential for industries that keep printing busy, like packaging and labeling. In this guide, we’re going to evaluate the inner workings of CI flexo presses, taking a closer look at their components, advantages and why they’re the perfect choice for anyone who desires their printing to be at the highest quality level.

What is a CI Flexo Printing Machine?

CI Flexo Press

A CI flexo printing machine, also known as a central impression flexo press, is a special printing press with a high output capacity and a high quality of printing on a wide variety of substrates. In contrast to the in-line flexo press that has multiple impression cylinders, the CI flexo press has a large central impression cylinder that is the main component of the printing process. This central cylinder is the core of the press and it is surrounded by a number of print units, each equipped with its own plate cylinder, anilox roller, and ink chamber.

Key Components of CI Flexo Press

A CI flexo printing machine is a marvel of engineering, comprising several key components that work in harmony to produce premium print quality.

ComponentQuantityFunction & Additional Info
Central Impression Drum1Provides a stable printing surface for accurate color registration and quality. Size affects maximum print width, typically 800mm-1500mm in diameter.
Satellite Flexographic Printing Units4-12Each applies a specific color, with the number of units determining the maximum colors per pass. Consists of an anilox roll, plate cylinder, and impression roller.
Infeed Guide1Feeds substrate into the press and aligns it, adjustable for various widths and thicknesses, possibly includes a web cleaner.
Nip Roll1Partners with the infeed guide to maintain substrate tension and alignment entering the press.
Interstation Dryers3-11Dry ink between printing units to prevent mixing and ensure sharp images. Varieties include hot air, infrared, and UV curing.
Fine Impression Adjustment4-12Allows precise pressure adjustments between the plate cylinder and central drum for substrate thickness variations.
Metering Roll4-12Controls ink transfer from the chamber to the anilox roll, with a textured surface for ink flow regulation.
Anilox Roll4-12Essential for regulating the ink supply. Ceramic-coated, engraved with cells to carry ink to the plate cylinder. Cell count/volume affects ink transfer, higher for finer details.
Plate Cylinder4-12Holds the flexographic printing plate made of photopolymer, changeable for different jobs or designs.

How CI Flexo Press Works

The CI flexo printing process begins with the preparation of the printing plates. The artwork is divided into separate color layers, and each layer is used to create a flexible printing plate. These plates, serving as the image carrier, are then mounted onto the plate cylinders in the print units.

As the substrate, such as a plastic film or paper, is fed into the CI flexo press, it is guided onto the large diameter impression cylinder. The central cylinder rotates, bringing the substrate into contact with each print unit in sequence. In each print unit, the anilox roller picks up a controlled amount of ink from the ink chamber and transfers it to the printing plate. The raised areas of the printing plate then transfer the ink onto the substrate, creating the desired image.

This process is repeated for each color layer, with the substrate making a complete revolution around the central impression cylinder. The precise registration ensured by the central cylinder allows for accurate color alignment and consistent print quality.

After printing, the substrate passes through the drying system, where the ink is dried and cured. The finished product is then rewound or fed into additional finishing processes, such as lamination or die-cutting, depending on the specific application.

Advantages of CI Flexo Printing

High-Speed Production

The speed of production is one of the most significant advantages of CI flexo printing which can be achieved. CI flexo presses can reach speeds of 300-600 meters per minute depending on substrate and ink type. Such a high-speed capability makes printers to be able to perform large print volumes fast, hence, the lead time and productivity are increased.

Superior Print Quality

CI flexo printing machines are particularly known for the fact that they provide superb print quality. The steady surface that the central impression cylinder creates, together with the advanced ink control systems and the high-resolution printing plates, allows CI flexo presses to print clear and vivid images with superior color consistency.

The anilox roller is one of the most important components in the printing process as it ensures that the ink is transferred evenly onto the substrate. Nowadays, laser engraving has become an advanced technology that enables anilox rollers to have high line screens of 800 to 1,200 LPI. These high-resolution anilox rollers enable the reproduction of fine details, smooth gradients and crisp text even on complicated substrates.

Moreover, the use of high-resolution flexographic printing plates that are made with digital plate imaging technology contributes to the overall print quality. These plates provide the enhanced dot structure and enhanced tonal range which are capable to produce images of the same quality as that of the offset printing.

Flexibility in Printing Substrates

Yet another remarkable benefit of CI flexo printing is its ability to adapt to a wide range of substrates, including thicker substrates and thinner substrates, as well as varying surface properties., thus allowing printers to address a variety of customers‘ printing needs.

Flexible Packaging Films: PE, PP, PET and other plastic films like PE.

Paper and Paperboard: Paper, cardboard, and corrugated materials coated and uncoated.

Foil and Metallic Substrates: Aluminum foils and metalized films.

Laminates and Multi-Layer Materials: Composite materials and laminates that are used in the packaging industry.

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Environmental Advantages

CI flexo printing offers several environmental advantages compared to other printing methods. One of the most notable benefits is the use of water-based inks. Water-based flexographic inks have low volatile organic compound (VOC) emissions, making them more eco-friendly than solvent-based inks used in other printing processes.

Additionally, the high-speed production capabilities of CI flexo presses lead to reduced energy consumption per unit of output. Faster printing speeds mean that more products can be printed in a shorter time frame, optimizing energy usage and minimizing waste.

Furthermore, advancements in plate-making technology have led to the development of solvent-free and water-washable flexographic printing plates. These plates eliminate the need for harmful solvents in the plate-making process, reducing the environmental impact of flexographic printing.

Disadvantages of CI Flexo Printing

While CI flexo printing offers numerous advantages, it’s important to consider some of its limitations:

Limited Deck Capacity

One of the drawbacks of CI flexo presses is their limited deck capacity compared to inline flexo presses. The central impression cylinder configuration restricts the number of print units that can be accommodated around the cylinder. Most CI flexo printing machines have a maximum of 10 to 12 print units, which may limit the color capabilities for certain applications.

However, it’s worth noting that advancements in ink formulations and printing plate technologies have somewhat mitigated this limitation. The use of high-pigment inks and expanded gamut printing techniques allows for a wider color gamut to be achieved with fewer print units.

Lower Production Flexibility

Another disadvantage of CI flexo printing is its lower production flexibility compared to inline flexo presses. CI flexo presses are designed for high-volume, long-run production, making them less suitable for short runs or frequent job changes.

The setup time required for changing printing plates and adjusting color registration on a CI press is typically longer than that of an inline press. This setup time can impact production efficiency when dealing with multiple short runs or frequent job changes.

However, recent advancements in automation and quick-change systems have helped reduce setup times on CI flexo presses. Some modern CI flexo printing machines feature automated plate changing systems and pre-register technology, which can significantly reduce changeover times and improve production flexibility.

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Core Applications of CI Flexo Presses

The core applications of CI flexo presses predominantly lie in the packaging industry and label printing. In the packaging sector, CI flexo printing machines are indispensable for producing high-quality, visually appealing packaging for food, beverages, personal care products, and pharmaceuticals. The technology’s ability to print on a variety of substrates makes it ideal for flexible packaging, such as pouches, bags, and wraps, which require durability and food safety. Label printing is another area where CI flexo presses shine, providing crisp, vibrant labels that can withstand environmental factors and handling. The adaptability and efficiency of CI flexo printing make it a backbone technology in these industries, driving innovations in packaging design and functionality to meet the requirements of the most demanding package printing applications.

Operating a CI Flexo Press: A Step-by-Step Guide

Operating a CI flexo printing press requires skilled operators who understand the intricacies of the printing process. Here’s a step-by-step guide to operating a CI flexo printing machine:

  1. Prepress: Prepare the artwork, create color separations, and generate high-resolution printing plates for each color.
  2. Plate Mounting: Mount the printing plates onto the plate cylinders in each print unit, ensuring proper alignment and registration.
  3. Ink Preparation: Mix and prepare the inks according to the job specifications, ensuring consistent color and viscosity.
  4. Anilox Roller Selection: Choose the appropriate anilox rollers based on the desired ink volume and line screen for each color.
  5. Substrate Loading: Load the substrate onto the press, ensuring proper tension and alignment.
  6. Press Setup: Adjust the press settings, including print pressure, registration, and drying parameters, based on the substrate and ink requirements.
  7. Print Run: Start the print run, monitoring the print quality and making necessary adjustments throughout the process.
  8. Quality Control: Perform regular quality checks, including color density, registration, and defect inspection, to ensure consistent print quality.
  9. Finishing: Once the print run is complete, the printed substrate is sent for finishing processes, such as lamination, die-cutting, or packaging.

Choosing the Right CI Flexo Press

When it comes to picking the perfect CI flexo press, there are a few important factors to consider. First and foremost, you’ll want to make sure the press can handle the size of your projects. Measure up the maximum print width you need and choose a machine that can accommodate it. Next, think about the complexity of your designs – how many colors do you need? Make sure the press has enough print units to bring your vision to life. It’s also crucial to consider the materials you’ll be working with. Whether you’re dealing with thin films or thick cardboards, your press should be able to handle them with ease. Don’t forget to think about your workload, too. Choose a press with a speed that can keep up with your production demands. And if you want to make your life easier, look for presses with nifty features like quick-change systems and automatic registration control. These can help you work more efficiently and cut down on wasted materials. By keeping these factors in mind, you’ll be well on your way to finding the CI flexo press that’s just right for you.


CI flexo printing has revolutionized the printing industry, offering high-quality, high-speed production capabilities for a wide range of applications. With its superior print quality, substrate flexibility, and environmental advantages, CI flexo presses have become the preferred choice for many businesses in the packaging and label printing sectors.

As the printing industry continues to evolve, CI flexo printing is poised to play a significant role in shaping the future of packaging and label production. With ongoing advancements in press technology, ink formulations, and plate-making processes, CI flexo presses will continue to push the boundaries of print quality and efficiency, delivering exceptional results for businesses worldwide.

KETE CI Flexo Press: Where Innovation Meets Quality

At KETE, we understand the importance of reliable and high-performance CI flexo printing machines. Our range of CI flexo presses combines cutting-edge technology with robust construction, delivering exceptional print quality and production efficiency.

The KETE CI flexo press is designed to meet the demands of the most challenging printing applications. With a maximum print width of 2,400 mm and speeds up to 250 meters per minute, our presses offer the capacity and productivity needed for high-volume production.

Our CI flexo printing machines feature advanced automation systems, including automatic plate changing, pre-register technology, and in-line inspection, ensuring quick changeovers and consistent print quality. The modular design of our presses allows for easy customization and expansion, adapting to your specific printing requirements.

At KETE, we prioritize quality and reliability. Our CI flexo presses are built with premium components and undergo rigorous testing to ensure optimal performance and longevity. We also provide comprehensive service and support, with a team of experienced technicians ready to assist you throughout the life of your press.

Partner with KETE for your CI flexo printing needs and experience the perfect blend of innovation and quality. Our commitment to excellence ensures that your business stays ahead of the competition, delivering outstanding results to your customers.

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