Holding device for holding a necked tubular object in a printing system and method of loading and unloading object

A holding device for holding a necked tubular object, the holding device comprising:

• a substantially annular gripper ring, the gripper ring comprising an annular base and a plurality of fingers that extend axially from the annular base, wherein
• each of the plurality of fingers comprises:
• a first portion extending axially from base of the gripper ring up to a boundary region, and
• a second portion extending axially from the first portion and connected to the first portion at the boundary region;
• and
• wherein, in its rest position, a maximum outer radius of each finger occurs at the boundary region between the first portion and the second portion such that, when an opening of a necked tubular object is axially pushed over the gripper ring, a force exerted by the opening of the necked tubular object on the second portion of each finger causes each finger to be progressively bent inwards towards the axis of the gripper ring until the opening of the necked tubular object has passed over the boundary region, whereupon each finger resiliently springs radially outwards such that an outer surface of the first portion contacts an inner surface of the necked tubular object, thereby providing a holding force for holding the necked tubular object onto the gripper ring.

A method of loading a necked tubular object onto a holding device, the holding device comprising:

• a substantially annular gripper ring, the gripper ring comprising an annular base and a plurality of fingers that extend axially from the annular base, wherein each of the plurality of fingers comprises:
• a first portion extending axially from base of the gripper ring up to a boundary region, and a second portion extending axially from the first portion and connected to the first portion at the boundary region;
• wherein, in its rest position, a maximum outer radius of each finger occurs at the boundary region between the first portion and the second portion such that, when an opening of a necked tubular object is axially pushed over the gripper ring, a force exerted by the opening of the necked tubular object on the second portion of each finger causes each finger to be progressively bent inwards towards the axis of the gripper ring until the opening of the necked tubular object has passed over the boundary region, whereupon each finger resiliently springs radially outwards such that an outer surface of the first portion contacts an inner surface of the necked tubular object, thereby providing a holding force for holding the necked tubular object onto the gripper ring;
• the method comprising:
• axially pushing the necked tubular object onto the gripper ring of the holding device with the necked tubular object being held in axial alignment with the gripper ring.

A printing system for printing on an outer surface of a tubular object, the printing system comprising:

• at least one printing station for printing on the outer surface of the tubular object;
• and
• at least one holding device for holding the tubular object during a printing process, the at least one holding device comprising:
• a substantially annular gripper ring adapted to be partially inserted into the tubular object, the gripper ring comprising an annular base and a resilient radially compressible portion configured to securely engage with an inner surface of the tubular object, wherein the resilience of the radially compressible portion causes the radially compressible portion to exert a radially outward mechanical restoring spring force when compressed, wherein the gripper ring further comprises a plurality of fingers that extend axially from the annular base, wherein each of the plurality of fingers comprises:
• a first portion extending axially from base of the gripper ring up to a boundary region, and
• a second portion extending axially from the first portion and connected to the first portion at the boundary region;
• and
• wherein, in its rest position, a maximum outer radius of each finger occurs at the boundary region between the first portion and the second portion such that, when an opening of a necked tubular object is axially pushed over the gripper ring, a force exerted by the opening of the necked tubular object on the second portion of each finger causes each finger to be progressively bent inwards towards the axis of the gripper ring until the opening of the necked tubular object has passed over the boundary region, whereupon each finger resiliently springs radially outwards such that an outer surface of the first portion contacts an inner surface of the necked tubular object, thereby providing a holding force for holding the tubular object onto the gripper ring.