Digital UV Printing and the glass surface condition
UV inks on the non absorbent glass surface
UV inks include special additives to reduce the surface tension in order to obtain a good wettability (ink spreading) on the glass, resulting in a good drop formation immediately after the ink drop has reached the glass surface. Wettability means the property of one liquid to shrink or to spread when touching the level of the surface itself.
UV inks and the non porous glass surface
Non porous materials offer less mechanical anchor points for UV ink to adhere to. Pre-treatment is necessary to make the surface rough and to enable mechanical ink adhesion. The flame coating, that is part of the WP Digital pre-treatment process performs this action.
UV organic ink and the inorganic glass surface
The two materials are incompatible from a chemistry point a view, a substance that has both an inorganic and an organic component is needed to create a bond between the glass and the UV ink. The adhesion promoter, silane based, is part of the WP Digital pre-treatment solution to increase adhesion.
General considerations of printing quality with UV and environmental friendly premises while printing
The CMYK (cyan, magenta, yellow, black) UV colours complemented by the diluted channels light magenta and light cyan make the winning balance between the smoothness of the print and the colour gamut (achievable colour) that the eye perceives. The ink is VOC free and metal free. During the printing process the drying is virtually instantaneous when exposed to UV lights.
The inks are transparent enabling superb visual effects when looking at the colour shades through pane of glass.
The colour saturation makes the decorated printed glass look like a photograph and makes the decoration of glass panes possible.