| 摘要 |
<p>A machine for printing on thin-walled frusto-conical containers having little resistance to transverse deformation is provided with rotatable mandrels for holding and centering the containers during printing. Each mandrel has a rotatable body provided with two axially spaced centering rings adapted to engage the walls of the container and centralize the container relative to the axis of the mandrel upon axial movement of the container on to the mandrel. The centering rings make sealing engagement with the walls of the container and subdivide the space enclosed between the container and the mandrel body into an end chamber between the base of the container and the outer end of the mandrel, and an annular chamber between the side wall of the container and the mandrel body. The mandrel body is provided with suction conduit means for extracting air from the end chamber so as to hold the container on the mandrel with the centering rings in sealing engagement with the container walls, and the mandrel body is also provided with pressure conduit means for supplying compressed air to the annular chamber to support the side wall of the container against transverse deformation during a printing operation.</p> |
