A seat module intended for a vehicle seat is designed as a seat cushion or backrest and can be actively ventilated. A releasing roller is disposed between a roll and a transport roller for nipping a medium and transporting the medium to a printing position. A control system monitors the sensing arrangement and an alarm can be activated. An offset eraser is configured to, based on the presence or absence of relative displacement between the first and second targets, determine whether or not the first and second targets belong to different vehicles, and when the first and second targets belong to different vehicles, erase the offset stored by the offset storage.