An object is to improve a user's convenience. There is provided a control unit for use in a liquid ejecting apparatus using a tank containing a liquid and a storage material attachable to and detachable from the liquid ejecting apparatus, and storing an amount of the liquid in the tank. After the storage material is not mounted on a predetermined place, the control unit receives an answer for a question to ask whether or not the liquid is injected to the tank.

A printing device includes a providing unit configured to provide to a printed material an identifier for managing the printed material. The providing unit prints the identifier with invisible ink on the printed material. The identifier is visually recognizable under special light and invisible under normal light.

A printing device includes a providing unit configured to provide to a printed material an identifier for managing the printed material. The providing unit prints the identifier with invisible ink on the printed material. The identifier is visually recognizable under special light and invisible under normal light.

A system for direct printing on a three dimensional article includes a plurality of print stations, each print station comprising a print head for delivering ink; a mover having a holder for securing a three dimensional article and at least one magnet; and a plurality of tiles each comprising energizable coils for producing an electrical field for effecting the at least one magnet in the mover to controllably float the mover about the plurality of tiles; where the plurality of print stations are proximal to at least some of the tiles in the plurality of tiles; and where the mover is configured to have six degrees of motion relative to the plurality of tiles to position a portion of the surface of the three dimensional article proximally normal to the print head. The system may further include curing stations, vision or inspection stations, and/or pre-treatment stations.

A system for direct printing on a three dimensional article includes a plurality of print stations, each print station comprising a print head for delivering ink; a mover having a holder for securing a three dimensional article and at least one magnet; and a plurality of tiles each comprising energizable coils for producing an electrical field for effecting the at least one magnet in the mover to controllably float the mover about the plurality of tiles; where the plurality of print stations are proximal to at least some of the tiles in the plurality of tiles; and where the mover is configured to have six degrees of motion relative to the plurality of tiles to position a portion of the surface of the three dimensional article proximally normal to the print head. The system may further include curing stations, vision or inspection stations, and/or pre-treatment stations.