A printing system for printing on an outer surface of a tubular object is provided. The printing system comprises at least one printing station for printing on the outer surface of the tubular object (100); and at least one holding device for holding the tubular object during a printing process. The holding device comprises: a substantially annular gripper ring (200) adapted to be partially inserted into a tubular object. The gripper ring comprises a radially compressible portion (201) configured to securely engage with an inner surface of the tubular object. The radially compressible portion exerts a radially outward mechanical restoring force when compressed.