Apparatus and method for printing on three-dimensional objects

A method of retrofitting a three-dimensional object printing system, the method comprising:

• providing a three-dimensional object printing system, the object printing system including a plurality of first print heads;
• installing a sub-assembly, the sub-assembly including an intermediate transfer member (ITM) having the form of a flexible endless belt with a release surface,
• an imaging station at which at least one ink composition that comprises a coloring agent, a resin and an optional liquid carrier, is deposited on the release surface to form an ink image, the imaging station including a plurality of second print heads, and
• a drying station at which the ink image is substantially dried, by evaporation of any liquid carrier in the ink or by exposure to radiation to cure the ink, so as to form a dried ink image on the release surface;
• and
• adapting said system to said sub-assembly, including retaining the plurality of first print heads separate from the imaging station or removing the plurality of first print heads,
• wherein the adapted system includes an impression station having a nip at which the ITM is compressed between an object having a longitudinal axis and an impression surface, so that the dried ink image is transferred from the release surface of the ITM to an outer surface of the object, and wherein each object rotates about its own longitudinal axis during passage through the impression station such that, at the nip, the outer surface of each object makes rolling contact with the release surface of the ITM, and wherein the impression surface forms part of a stationary anvil, the ITM sliding relative to the impression surface during passage through the impression station.

A method of printing on an outer surface of a three-dimensional object having a longitudinal axis, the method comprising:

• depositing on a release surface of an intermediate transfer member (ITM) having the form of a flexible endless belt at least one ink composition that comprises a coloring agent, a resin and an optional liquid carrier to form an ink image;
• substantially drying the ink image, by evaporation of any liquid carrier in the ink or by exposure to radiation to at least partially cure the ink, so as to form a dried ink image on the release surface;
• and
• compressing, at a nip of an impression station, the ITM between an object and an impression surface, so that the dried image is transferred from the release surface of the ITM to an outer surface of the object, wherein the object rotates about its own longitudinal axis during passage through the impression station such that, at the nip, the outer surface of the object makes rolling contact with the release surface of the ITM, and wherein the impression surface forms part of a stationary anvil, the ITM sliding relative to the impression surface during passage through the impression station.