Special inks and industrial inkjet printing systems

Inkjet printing is the digital printing process with the greatest development potential. Its great strength is apparent primarily in smaller individualised runs through to batch size 1. As a result, the process is ideally suited to individualise decorative products, like ceramic tiles or flooring and wall decorations. In addition, inkjet printing can be used to print on a great variety of different materials such as textiles and polymers. This enables functional coatings, complex structures for printed electronic articles or anti-counterfeiting measures (passports, credit cards). In particular, in the area of printed electronics, inks based on CNTs and nanosilver particles, have great potential for use in conventional electronic components such as in the manufacturing of RFID tags or foil displays.

The two printing processes:

Inkjet printing systems fundamentally operate on the same principle: The ink is drawn out of an ink reservoir and jetted in small droplets onto the substrate to be printed . In doing so, differentiation is made between two printing processes: Continuous Ink Jet and Drop on Demand.

Continuous Ink Jet (CIJ): A continuous ink spray is split into individual droplets through a piezoelectric oscillator and ejected through a nozzle. After leaving the nozzles, the droplets are electrically charged in order to deflect them via electrodes. If the droplets are not required for printing, they can be recycled via an ink return system. The CIJ process is used primarily in industrial applications, e.g. for individual markings such as use-by dates, serial numbers or mass mailshots.

Drop on Demand (DOD): A printing head, comprising multiple nozzles, is moved over the substrate, row-by-row. In doing so, only certain defined points are printed. The flightpath of the droplets is not changed. The individual nozzles can eject droplets of various sizes using heating elements, piezo crystals or pressure valves. The individual nozzles can be closed to the desired size when required via heating elements, piezo crystals or pressure valves. DOD inkjet printers are used in domestic situations, in offices and in industry. The printing process is ideally suited for printing electronic circuitry (e.g. RFID chips) or three-dimensional structures.

Ink formulation
Printing systems
Process technologies
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