What is Flexography printing

We compare here the difference between Flexography and Lithography

Flexography (often called flexo printing) is a high-speed printing process that uses flexible relief plates made from rubber or photopolymer. Ink is transferred from an ink roller (anilox roller) to the raised areas of the printing plate, which then prints the image onto a wide variety of materials.

It is widely used for packaging and labels because it can print on materials that are difficult for other printing methods, such as plastic films, foil, cardboard, corrugated boxes, and paper. It offers outstanding results and quality.

Flexography

Uses flexible raised printing plates (relief printing).
Prints well on rough, flexible, and non-porous materials such as plastic, film, foil, and board.
Uses fast-drying inks, making it ideal for high-speed production.
Primarily used for packaging, labels, and flexible packaging.
Excellent for large-volume packaging runs.

Lithography (Offset Printing)

Uses flat printing plates based on the principle that oil and water repel each other.
smooth, high-quality papers like silk, gloss, or uncoated stock.
Produces very high image quality with sharp detail and smooth colour gradients.
Commonly used for books, magazines, brochures, catalogs, and marketing materials.
Excellent for high-quality commercial printing.

Examples of Flexography Printing

Flexography is commonly used to print:

Food packaging
Plastic bags
Product labels
Corrugated shipping boxes
Folding cartons
Gift wrap
Tissue paper
Paper napkins
Shopping bags
Envelopes
Ice cream cartons
Disposable paper plates and cups
Flexible pouches
Adhesive tapes

What is a Flexo printing press?

A flexographic printing press is a substantial printing machine composed of flexible plates and rollers. Traditionally, printers utilised rubber Flexo plates; however, advancements in technology have led to the use of flexible photopolymer wrapped around a roller. Essentially, a Flexo printer functions similarly to a large stamp, capable of printing at speeds of up to 2,000 feet per minute.

There are five distinct types of flexographic printing presses:

Stack Press: This type features vertically stacked decks that enable printing on both sides of the substrate.
Central Impressions Press: This design includes a central impression cylinder.
In-Line Press: The decks are arranged in a horizontal line, facilitating easier operations.
Wide-Web Press: This Flexo press is specifically designed to accommodate wider rolls of substrates.
Narrow-Web Press: This variant is tailored for handling smaller substrates, such as labels.

How it works

As you can see from the main image; A flexible photopolymer plate is wrapped around a rotating cylinder for each colour. In a manner akin to the letterpress printing technique, the graphics and text for each colour are raised above the surface of the plate.

Only the elevated portions of the plate are inked. A typical flexographic press is composed of four types of rollers: a fountain roller, an Anilox roller, the plate cylinder, and the impression cylinder.

The fountain roller conveys ink from an ink pan to a steel or ceramic ink-metering Anilox roller, which subsequently transfers it to the plate cylinder. As the paper passes between the plate cylinder and a polished metal impression cylinder, the ink is applied to the substrate.

The impression cylinder applies the necessary pressure to ensure the ink is successfully transferred from the plate to the substrate.

In Flexography, the Anilox roller plays a vital role in providing a uniform thickness of ink to the flexible printing plate. Each Anilox roller is equipped with finely engraved cells that are designed to retain a specific volume of ink.

An optional doctor blade may be employed to scrape the surface of the Anilox roller, guaranteeing that only the ink stored in the engraved cells is transferred to the printing plate.

Many printing companies also combine flexography with digital printing (toner or inkjet) for shorter production runs, personalised packaging, or variable-data printing where each printed item contains different information (such as serial numbers, barcodes, or names).