"ANALYSING THE REPRODUCTION QUALITY OF BRAILLE DOTS ON SELF-ADHESIVE LABELS PRODUCED WITH UV INKJET PRINTING"

Abstract

Although modern digital technologies have successfully replaced many traditional methods of communication, including the use of braille for the blind and visually impaired, braille remains an important element of literacy for this vulnerable group. To accurately recognise the braille dots that make up the standardised characters, it is important that they have the correct dimensions, both in size and height. In this study, the reproduction quality of braille dots on self-adhesive labels was analysed. The elements were printed using the UV inkjet printing technique with a different number of passes (layers) to define and analyse the changes that occur with an increasing number of UV varnish layers. The samples were printed with 2, 4, 6, 8, 10 and 12 layers of UV varnish. The image analysis with the scanning electron microscope (SEM) focussed on the change in the diameter of the dots. The braille dots show deviations from the digitally defined diameter in the graphic prepress (1.60 mm), especially in the horizontal direction, which is due to the spreading of the varnish and the movement of the print head. The first layers of UV varnish behave differently depending on the substrate, while the application of further layers reduces deformation and improves dot formation. Lifting the print head led to a stronger spreading and deformation of the dots in both samples.