Abstract: A printing apparatus comprises a jetting assembly including a plurality of nozzles for ejecting droplets on a substrate moving relative to the jetting assembly, a mechanism for increasing the displacement of the jetting assembly relative to the substrate, and a sensor configured to activate the mechanism for increasing the displacement of the jetting assembly upon detecting a predetermined dimension of the substrate surface relative to the jetting assembly.

Abstract: A workpart chuck centering mechanism moves towards the axis of rotation of the chuck as the chuck rotates in an eccentric non-centered position. The centering mechanism includes two independent shoes. Each shoe is driven by a servo-motor and encoder. The two shoes function in a cooperative manner to center the workpart. A sensing device monitors any eccentric movement of the workpart and controls the positioning of the shoes. The two shoes and the sensing device are mounted on a base which can pivot about the chuck axis. The directions of movement of the respective shoes are displaced 90.degree. relative to one another and intersect at the chuck axis.

Abstract: A workpart chuck centering mechanism moves towards the axis of rotation of the chuck as the chuck rotates in an eccentric non-centered position. The centering mechanism includes two independent shoes. Each shoe is driven by a servo-motor and encoder. The two shoes function in a cooperative manner to center the workpart. A sensing device monitors any eccentric movement of the workpart and controls the positioning of the shoes. The two shoes and the sensing device are mounted on a base which can pivot about the chuck axis. The directions of movement of the respective shoes are displaced 90.degree. relative to one another and intersect at the chuck axis.