Analysis on the Difference between 6-Color CI Flexo Press and Stacked Stacked Flexo Press
I.CI Flexo Press (Central Impression Flexo Press)
The core structure of A CI flexo press, also known as a "central flexo press or Satellite Flexo Printing Machine, is as follows:
All printing color units are arranged around a central impression cylinder.
Throughout the printing process, the substrate is always attached to the surface of the central impression cylinder;
"6-color CI flexo press" means the device has 6 separate printing units for continuous 6-color printing.
CI structure is the most mainstream flexible printing method in the soft packaging industry.
2. Stacked Flexo Press
Stacked a stacked flexo press feature:
Vertical arrangement of printing apparatus;
The substrate completes the color matching through each color unit in turn.
The material undergoes tension transfer and path changes in each color unit.
This structure is an older and more traditional form of flexo printing.
II. Core structural differences
1. CI Flexographic Printing Machine Structural Characteristics
CI machine has a "central large cylinder" structure:
All color groups have the same impression cylinder;
The material maintains a stable wrap angle throughout the printing process.
Short film movement path;
Tension fluctuations less.
The main advantages of this structure are:
It prioritises material stability.
Therefore, it is especially suitable for thin film materials which are easy to stretch and deform.
2.Structural Characteristics of Stacked Flexo Printing Machines
In a stacked structure:
Each color group has a separate impression system;
The material needs to keep moving up and down.
Material feeding distance between different color groups is relatively long.
Tension control relies on multiple traction systems.
Its essential characteristics are:
The equipment structure is simple, but material stability is poor.
III. Differences in Registration Accuracy (The Most Critical Difference)
Registration accuracy is the key difference between the two devices.
1.Reasons for High Registration of CI Flexographic Printing Machines
CI Machine:
The material remains in contact with a central impression cylinder;
The position of the materials between color groups remains basically the same.
The tensile and shrinkage of the film are strictly controlled.
Temperature deformation and tension accumulation errors are minimal.
Therefore:
Stabilized registration even at high speeds; small text, fine lines, and halftone gradients can be replicated steadily;
More suitable for high quality color printing.
The registration accuracy of modern CI machines is usually:
±0.1 mm or more.
2.Analysis of the Reasons for Larger Registration Errors of Stacked Flexographic Printing Machines
In stacking devices:
The material moves freely between different color groups.
Each color group introduces new tension to the material;
Films are prone to longitudinal stretching; errors accumulate easily during multi-color overprinting.
Therefore:
At high speed, the stability of registration decreases significantly.
Not suitable for fine halftone printing; Color gradients is prone to deviation.
The problem is particularly acute in plastic film printing.
