A refill arrangement for an ink reservoir of an automatic writing system has an ink reservoir, an adaptor, and a refill container provided as individual parts and to be combined for filling the ink reservoir such that the adaptor connects the refill container to the ink reservoir and such that the refill container, the adaptor, and the ink reservoir are hermetically sealed relative to the ambient atmosphere when connected. The refill container is positioned vertically above the ink reservoir in a filling position of the refill arrangement. The refill arrangement operates pressureless or by gravity feed. The adaptor has a housing, a first connector arranged in the housing for receiving a connecting piece of the ink reservoir and a second connector arranged in the housing for receiving a connecting piece of the refill container. The housing has a filling channel connecting the first and second connectors. The adaptor has a valve stop and seals that seal the connecting pieces in the respective first and second connectors during filling.