Exploring Flexographic Printing - A Technical Review

September 12, 2024 by Colin Darcel

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Flexographic printing (also referred to as flexo) is a versatile printing technique widely used for packaging materials, labels, and other substrates. This method has grown significantly in popularity due to its adaptability, cost-efficiency, and high-speed production capabilities. In this blog, we will take a technical dive into the flexographic printing process, its components, and provide a comparison to offset printing.

Understanding Flexographic Printing

Flexographic printing is a form of relief printing where the image area is raised above the non-image areas on the printing plate. This raised surface is inked and then pressed against the substrate to create an impression. Here is a step-by-step breakdown of the elements involved in the printing process.

Plates: Flexographic plates are typically made of a flexible polymer material. These plates are wrapped around cylinders and have raised images that are inked for printing. The flexibility of these plates allows them to conform to various substrates, including paper, plastic, and metal films.
Inking System: The inking system in flexo printing involves an anilox roller which is a metal or ceramic cylinder covered in tiny, engraved cells that carry the ink. The depth and size of these cells determine the amount of ink transferred to the plate.
Doctor Blade: A doctor blade is used to scrape excess ink from the anilox roller, ensuring a consistent amount of ink is applied to the printing plate.
Printing Units: Each color in a flexographic print job requires its own printing unit. These units are aligned to ensure precise registration of each color.
Ink: Flexo inks can be solvent based, water-based, oil-based, or UV-curable.

Key Advantages of Flexographic Printing

✔️ Versatility: Flexographic printers can print on a wide range of substrates, from paper and cardboard to plastics and metallic films. This versatility makes it ideal for packaging applications.

✔️ High-Speed Production: These presses can run at high speeds, making them suitable for large-volume print runs.

✔️ Cost-Effective: The production of flexographic plates is generally less expensive than the plates used in other printing methods, such as offset or gravure. Additionally, the ability to print on various substrates without the need for additional preparation can help to reduce costs.

✔️ Efficient Ink Transfer: The anilox roller ensures a precise and consistent transfer of ink to the plate, resulting in high-quality prints with limited ink waste.

Press Cleaning

Cleaning flexographic presses is an especially important part of regular maintenance. Keeping on top of cleaning your press helps to mitigate damage caused by hardening ink. The type of ink used on the press will determine which cleaning solution you need for your press. Solvents like n-Propanol and Propyl Acetate are examples that are commonly used.They are often mixed with flexographic inks that can contain nitrocellulose which is combustible. Maratek can provide equipment to safely recover solvents for reuse and reduce your waste disposal costs.

For printers that value the environment and wish to reduce their production costs, solvent recovery is a great process to include in your press maintenance routine. By using a Maratek solvent recovery system, these waste solvents can be recovered and recycled for reuse in the production process. This limits solvent waste, solvent disposal costs, virgin solvent purchasing costs, and the environmental impact of cleaning presses.

With Maratek’s FLEXO line of products, you can expect to recycle up to 95% of your used flexographic solvents.

Comparing Flexographic Printing to Offset Printing

Offset printing, another major printing process, is often compared to flexographic printing. The following is a detailed comparison between the two.

	Flexographic Printing	Offset Printing
Printing Plates	Uses flexible polymer plates with raised images.	Uses flat plates with image areas that attract ink and non-image areas that repel ink.
Ink Transfer	Ink is transferred directly from the anilox roller to the plate and then to the substrate.	Ink is transferred from the plate to a rubber blanket and then to the substrate.
Substrate Compatibility	Can print on a variety of substrates, including non-porous materials.	Primarily suited for porous materials like paper and cardboard. Printing on non-porous substrates often requires additional coatings or treatments.
Ink Types	Uses water-based, solvent-based, oil-based, UV-curable inks.	Typically uses oil-based, synthetic, or UV-curable inks.
Print Quality	Flexo has made significant advancements in print quality but still lags behind offset in terms of fine detail and resolution.	Known for its high-quality prints with good color consistency and detail.
Production Ppeed	Generally faster due to simpler inking systems and quick-drying inks.	Slower due to more complex ink transfer systems and drying times.
Setup & Running Costs	Lower setup costs due to cheaper plate production and less preparation required for different substrates.	Higher setup costs because of more expensive plates and the need for additional treatments for non-porous substrates.
Applications	Ideal for packaging, labels, and flexible materials.	Preferred for high-quality commercial printing such as brochures, business cards, and posters.

Flexographic printing has firmly established itself in the printing industry due to its versatility, cost-efficiency, and adaptability. While offset printing remains a preferred choice for high-quality commercial print jobs, the ability of flexographic printing to print on a wide range of substrates at high speeds makes it indispensable for packaging and labeling applications. As technology evolves, flexographic printing will offer even greater quality and sustainability. By understanding the technical aspects and benefits of flexographic printing, businesses can make informed decisions about the best printing methods for their specific needs, balancing quality, cost, and environmental considerations.

If you would like to learn more about how you can minimize your production costs and help preserve the environment, contact Maratek today.