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The Basic Flexographic Print Unit: Components and Functionality

Flexographic printing is a popular method used in the packaging and label industries due to its versatility and cost-effectiveness.
In this article, we will explore the four essential components of a basic flexographic print unit and delve into their roles and functions in the printing process.
Flexographic printing

The Fountain Roll

The fountain roll, also known as the wiper roll, is covered with natural or synthetic rubber and positioned to rotate in a reservoir of flexo ink.

Its main purpose is to pick up and deliver ink from the reservoir to the ink-metering (anilox) roll.

By rotating against the anilox roll, excess ink forms a puddle behind the point of contact, allowing only ink in the engraved cells to transfer to the printing plates.

The fountain roll is typically driven slower than the anilox roll, acting as a "wiper" to doctor the ink to an even film.

Ink-Metering (Anilox) Roll

The anilox roll transfers a measured amount of ink to the surface of the printing plate.

It is covered with tiny engraved cells, which can range from 80 to 1,200 per linear inch.

The cell count determines the volume of ink delivered to the plates, thus affecting the printed color.

Selecting the correct anilox roll for a specific application is crucial and depends on factors such as substrate type, ink type, and the type of work being printed (solids, type, halftones, etc.).

Anilox Roll

Plate Cylinder

The plate cylinder, usually made of steel, is installed between the ink-metering roll and the impression cylinder.

Printing plates are mounted on the plate cylinder using sticky-back adhesive.

The raised impression areas on the printing plate pick up ink from the ink-metering roll and transfer it to the substrate.

Depending on the type of printing plates used, the cylinder may be integral, demountable, magnetic, or fitted with a sleeve.

Impression Cylinder

The impression cylinder is a smooth, highly polished roller that supports the substrate when it contacts the printing plate.

Its surface speed must match that of the printing plate and the anilox roll to prevent printing defects like slurring and smearing.

The accuracy of the impression cylinder's dimensions, concentricity, gearing, and bearing fit is critical for maintaining print quality.

Two-Roll System with Doctor Blade

To improve ink distribution and control, press manufacturers introduced the doctor-blade system.

The doctor blade, set at a 30° angle with the anilox roll, removes excess ink, leaving only the ink contained in the engraved cells for transfer.

Proper alignment, adjustment, and maintenance of the doctor blade are essential for effective doctoring.

Chambered Doctor-Blade System

This system utilizes two doctor blades: a reverse-angle metering blade and a trailing containment blade.

They are enclosed in a box-like chamber, reducing exposure to air and ensuring tight viscosity control.

This system is popular for high-speed, wide-web, and corrugated postprint presses.

Continuous Inking

Flexographic inks are fast-drying, so the anilox roll must continue rotating when the press is in a non-printing mode to prevent ink from drying in the cells.

Proper separation of the anilox roll from the plate cylinder during idling is critical to avoid plate wear and ink drying issues.


Understanding the basic flexographic print unit and its components is vital for achieving high-quality and consistent print results.

Each component plays a specific role in the ink transfer and printing process, and careful selection, maintenance, and alignment are essential for successful flexographic printing operations.