Abstract: A device (100) such as a mobile robot for printing an image on a floor surface (1) is described. According to an exemplary embodiment, the mobile robot comprises a control system (117) and a printing system. The printing system has at least one colorant tank (110, 111, 112) with colorant and at least one spraying arm (201, 202, 203) having multiple nozzle assemblies (211) situated next to one another. The nozzle assemblies (211) each have a valve (212) that can be controlled by the control system and a colorant nozzle (210, 220, 230) by means of which colorant can be applied to the floor surface (1).