Abstract: The invention relates to a process for printing a substrate (7) containing curved surface sections by using an ink printing assembly with a movable print head (8) comprising an ink carrier (1) having an ink layer, the ink layer being irradiated regionally in such a way that heat bulges are formed in the ink layer which cause the splitting of ink droplets so that the ink printing assembly is working as nozzle-less droplet ejector for ejecting droplets of ink from the ink layer, where the distance between the print head (8) and the curved sections of the substrate (7) is adjusted by moving the print head relative to the substrate by providing the print head with three degrees of freedom in translation, allowing horizontal (Tx), vertical (Tg) and in depth (Tz) translations.