Ink development and transfer in printing
Our key competence is analysing and understanding factors affecting ink transfer in printing processes and modifying materials suitable for printing.
In addition to graphical printing, different printing methods are increasingly utilised in new application areas. Utilisation of novel inks or fluids and substrates, as well as different process flows, can cause unexpected complications in printing performance.
VTT has a long experience in graphical printing and surface modification research that creates a strong base to study material runnability and interactions with other printing materials in process regardless of the application. Based on our procedures that are not only limited to standard methods, equipment and interdisciplinary approach, we can respond to the most difficult research challenges.
Highly valued competence in printing materials and processes
Our expertise covers the whole printing process: web runnability in roll-to-roll production, ink requirements of different printing methods, particle dispersing, nip phenomena, ink substrate interactions, substrate modification and effect of drying on ink layer and substrate.
The research approach can be theoretical, like studying ink transfer, spreading and absorption to substrate by using the finite element method (FEM) modelling or more practical, like printing material characterisations or test printings.
Figure1. Modeling of offset printing blanket feeding in nip, FEM - Strains in nip. On the left positive feeding and on the right negative feeding.
Versatile selection of research equipment and methods
Test printings can be done in laboratory scale with gravure, flexo, offset and ink-jet methods, and in semi-pilot scale (roll-to-roll) with gravure, flexo and inkjet methods. In addition printing of 3D surfaces can be studied by system based on integration of six-axis robot and inkjet printhead. Moreover we are able to integrate the inkjet printheads nearly to any existing roll-to-roll process, when necessary.
Wide selection of standard devices is complemented with our internally developed innovative laboratory and online instruments, such as devices to measure web runnability, online imaging systems for continuous process and high speed imaging through nip. The chemical and physical properties of substrates can be characterised and modified by different treatments, like plasma, corona or by applying a thin coating layer.
Figure 2. Photovisualisation of electric assisted ink lifting in gravure printing.