Features of flexographic printing technology:
- high and stable quality of printing comparable with gravure printing technology;
- excellent precision of registers - "adjusting" thanks to the application of direct drives in the machines;
- profitability of producing short orders due to a limited amount of waste during machine preparation;
- fast realization of orders due to a quick process of preparing the printing plate;
- relatively low cost of printing plates;
- it is possible to implement unlimited amounts of prints
Flexographic printing machines:
- four printing machines by Soma:
Somaflex MIDI 80-8 EG - solvent;
- Somaflex MINI 80-8 UV;
- two Somaflex MIDI II 100-8 EG machines
- one printing machine by BOBST:
- BOBST 20SIX
Structure: central cylinder
Number of colors: 8: 8
Max speed: 450m/min
Print width: 800, 1000 and 1250 mm
Basic elements of the machine structure:
- central cylinder common to all printing unit; its advantage is total stability of the substrate during printing – such a solution facilitates adjusting and decreases stretching of the substrate;
- printing units;
- rewinder and winder;
- inter-section drying system, flexo UV machines – they are UV radiating lamps;
- drying tunnel (system of solvent-based inks);
- printing visualization system - BST Premius with a possibility to control the quality of printing barcodes
- ink system equipped with viscometers to control the ink viscosity;
Printing with inks:
1. Pouring an ink into the ink cup by the operator;
2. Administering an ink through the pump into the doctor blade chamber;
3. The ink from the doctor blade chamber is forwarded on the anilox sleeve.
The anilox sleeve - a sleeve with a ceramic top coat on which cups transferring the ink onto the printing plate are engraved.
The size of cups can vary. Their size and depth impact the amount of the transferred ink.
4. Transferring the ink on the printing plate installed on the printing sleeve.
5. Transferring the ink on the printing surface by pressuring the printing cylinder.
6. Preserving the printed ink through evaporation of the solvent or UV radiation.
Fundamental flexographic printing principle:
"printing a wet ink on a dry ink – only then ink trapping can be 100%"