A printer is disclosed having a media unit which can move relative to a printing unit. Until now, difficulties in aligning the media unit in the printer always resulted in a poor printing quality. To rectify this, the disclosed printer provides that the printing unit is designed so that it can move inside the housing, and elements are provided for aligning the printing unit with the media unit so that the printing unit and the media unit can be aligned with one another when the media unit is pushed in the direction of insertion. A resilient element enables the printing unit to be advantageously tensioned, in a manner that equalizes tolerances, against the support of the media unit in an operating position. This enables an advantageous equalization of work tolerances and positional tolerances, and the position of the print head relative to the medium to be printed.