Large format printer

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Large format printers (English: Large Format Printer , LFP) are devices for printing large-format motifs . Inkjet printers with print widths between 1.3 m and 5 m are preferably used. In extreme cases such as the Infinitus printer, the printing width is twelve and the length up to 50 meters. In some areas (e.g. technical drawings ) they are the technical successors of plotters and are sometimes incorrectly referred to as such.

A whole range of media can be printed, such as textiles, self-adhesive films, PVC tarpaulins or poster paper, but also rigid materials such as Plexiglas, PVC rigid foam panels or aluminum composite panels. The latter three are u. a. also processed on so-called flatbed printers (UV direct printers). The materials must have a surface suitable for inkjet printing. The only exception is currently UV direct printing , where it is possible to print on almost all materials (including wood / glass etc.).

Printing technology

In general, a distinction must be made between five printing processes in large format printing:

  • Continuous inkjet: the ink is circulated in the print head and only deflected electrostatically onto the printing material when required
  • Drop on Demand (DOD): the ink is static in the print head and is ejected when necessary (as in bubble jet printing ), the first printer based on DOD was the Siemens PT-80
  • UV direct printing : the ink is applied directly to the material and cured with UV light
  • Thermal transfer printing: Resin ink is transferred to the printing material from an intermediate carrier (ribbon) using heat
  • Electrophotography : Toner is picked up by photosensitive, electrically charged drums and transferred to the printing material. The print motif is fixed on the printing material by means of heat and pressure.

The process of dye sublimation printing occupies a special position. Here, the print motif is first printed mirror-inverted on a transfer material and then ironed with heat onto the substrate (textiles) to be printed.

Inks and pigments

The following four types can be distinguished:

  • Solvent based ink, e.g. B. methyl ethyl ketone , classic as well as ecologically optimized (Solvent, EcoSolvent)
  • Water-based ink
  • UV ink, is cured with UV light
  • Latex ink, combined water-based and solvent with latex as a binder, is thermally cured

Finishing and processing

After printing, the substrates can be prepared for long-term outdoor use. This is done by a transparent coating of the printed material. B. by painting, often by applying a protective film (optionally matt or glossy) by means of lamination . Such coatings are usually also UV-resistant and prevent premature fading of the colors due to exposure to light as well as direct damage to the print due to mechanical influences.

Individual evidence

  1. ↑ Explanation: Inks for digital printing media. In: Small encyclopedia on the subject of inks in digital printing. com2C GmbH & Co. KG, accessed on November 27, 2019 .