Method and apparatus for guiding an elongated generally cylindrical member past a non-contact printing station

In a system for printing indicia on a substantially continuous length elongated member having a three-dimensional external surface, said system including means for advancing the member along its longitudinal axis past a printing station having non-contact printing means selectively operable to apply indicia to the external surface of the member;

• the combination therewith comprising guide means cooperative with the elongated member to guide it past the printing means, said guide means including a first pair of guide rollers defining a nip cooperative with the elongated member downstream from the printing means, said first pair of guide rollers being operative to substantially prevent rotation of the elongated member about its longitudinal axis without contacting indicia applied to the member by said printing means, a second pair of guide rollers defining a nip cooperative with said elongated member upstream from the printing means, each roller of said first and second pairs of rollers having unidirectional means preventing rotation of the roller in a direction which would allow rearward longitudinal movement of the elongated member, and a pair of pivot rollers operatively associated with each of said first and second pairs of guide rollers to assist in stabilizing the elongated member as it passes the printing means.

In a system for printing indicia on a substantially continuous length elongated member having a three-dimensional external surface, said system including means for advancing the member along its longitudinal axis in a path past a printing station having non-contact printing means selectively operable to apply indicia to the external surface of the member;

• the combination therewith comprising guide means cooperative with the elongated member to guide it past the printing means, said guide means including a pair of cylindrical guide rollers defining a nip therebetween cooperative with the elongated member downstream from the printing means, and a reference plate supported closely adjacent the path traversed by the elongated member, said cylindrical rollers being supported for rotation about parallel axes inclined to the direction of movement of the elongated member so as to bias the elongated member against said reference plate and substantially prevent rotation of the elongated member about its longitudinal axis without contacting indicia applied to the member by said printing means.

A method for guiding a substantially cylindrical elongated member longitudinally past a non-contact printing head operative to apply indicia to the external cylindrical surface of the member as it moves past the printing head, said method comprising the steps of:

• (a) passing the elongated member longitudinally through first guide means upstream from the printing head,
• (b) passing the elongated member longitudinally through second guide means downstream from the printing head so that the elongated member transverses a straight path between the first and second guide means, said second guide means including a pair of guide rollers defining a nip therebetween operative to receive the elongated member with the guide rollers engaging the member along diametrically opposed lines of contact, and
• (c) providing a reference surface and urging the elongated member against said reference surface as it passes through said nip so as to maintain said member in said straight path and substantially prevent rotation of the elongated member about its longitudinal axis as it passes through said nip.