Driving device for a print head

Claim 1

A driving device for a print head including printing means actuated at predetermined times for marking characters on a data carrier carried by a print roll, comprising: motion converting means comprising a housing including an interior continuous gear path; said housing being coupled to said print head; said gear path comprising a pair of opposing straight path portions substantially parallel to the axis of said print roll; said straight path portions being joined, at each end thereof, by respective curved path portions; rotatable pinion means in continual engagement with said gear path; said pinion means being coupled to the shaft of a motor driving means; said straight path portions being mutually separated by a distance greater than the outside diameter of said pinion means and said curved path portions being mutually separated by a distance substantially greater than the distance separating said straight path portions; rotary motion of said pinion means being converted to reciprocating movement of said housing and corresponding movement of said print head; said housing and said print head being coupled by guide means comprising a guided member joined to said housing and a guiding member joined to said print head; said guided member comprising at least a pair of projections extending substantially perpendicular to said straight path portions and said guiding member comprising at least a pair of channels, each one receiving a respective projection; said projections being capable of relative movement within said respective channel in a direction perpendicular to said straight path portions and said channels preventing relative movement with respect to its respective projection in a direction parallel to said straight path portions; said guide means permitting movement of said housing and said print head in a direction substantially parallel to the axis of said print roll whenever said pinion engages said straight path portions and said guide means allowing movement of said housing in a direction substantially perpendicular to the axis of said print roll whenever said pinion engages said curved path portions.