Types of Anilox rollers in flexo printing

What is an anilox roller?

An anilox roll is a cylinder composed of a steel or aluminum core covered with an industrial ceramic, typically Chromium oxide powder, whose surface is etched with millions of dimples, or anilox cells. There are various types of anilox rollers.

How anilox roller works ?

Normally, an anilox roll is used in conjunction with an inking unit in order to transfer ink to paper. During the inking process, the anilox roll transfers the ink to the doctor blade plate. Printing plates are the plates on which ink is applied. The material is generally designed to accept and retain ink. The most common materials are polyester film, photopolymers, and metals.

What are the different types of an anilox rollers form which you can choose?

The press operator selects an anilox roll with a higher or lower line screen according to the detail of the images to be printed.

More ink is squeezed out from the anilox roll and onto the paper web with a higher line screen. In spite of this, the screen clogs up very quickly due to its fineness. In order to achieve the desired amount of ink flow, the operator will also adjust the amount of pressure applied to the anilox roll. 

Characteristics of an anilox roller

The anilox roller has three main parameters,

• Lines per inch
• Cell angle
• Cell volume(BCM).

These three parameters will be noticed by both the user and the supplier when ordering or processing a new anilox roll. 
Lines per inch (LPI)

This parameter is used to determine the lines per inch on the anilox roll.

Cell Angle:

This parameter is used to determine the cell angle on the anilox roll.

Cell volume (BCM)

This parameter is used to determine the volume of the cells in the anilox roll.

Every printed part should begin with a construction sheet before selecting anilox rollers. The construction order should contain all the information necessary for each printed piece, including the parameters required for the printing press after getting the customer’s signature. Typically, anilox rollers are specified by their line distribution (LPI) and cell volume (BCM), as the rollers may be interchangeable in the printing press.

As an example, one printing unit prints the red plate using 600LPI, 1.8BCM anilox rollers. As a result, the red plate anilox rollers are only 500LPI, 3BCM, and 700LPI, 1.5BCM in the next printing unit. There are two types. This is the time to select the anilox roller with the closest parameters, namely 700LPI, 1.5BCM.

Therefore, the concept of preferring shallower cell anilox rollers is not appropriate. Under the condition of ensuring the best ink transfer and ink drying, the main consideration should be to choose the largest LPI (lines per inch). In order to achieve the best density.

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