MATRIX WIRE PRINT HEAD AND METHOD FOR THE MANUFACTURE THEREOF

摘要

This invention relates to an improved wire matrix print head having significantly reduced friction on the print wires and to a method for the manufacture of the improved print head. The print head has an element formed at one end for mounting the nonprinting end of the wires and a print guide member having end openings arranged in a predetermined print pattern mounted at the other end of the print head, the print wires each passing through and being supported in a separate one of the openings. First and second guide plates are also provided, each of the plates having n openings formed therethrough which openings are arranged in predetermined patterns and through which openings the print wires are adapted to pass. Each wire passes through a separate opening in each of the guide plates. The guide plates are mounted at predetermined positions between the nonprinting end of the wires and the print guide member. The predetermined positions are selected such that the first guide plate is spaced from the print guide member by a first predetermined distance, the guide plates are spaced from each other by a second predetermined distance, and the second guide plate is spaced from the nonprinting ends of the wires by a third predetermined distance, the first, second and third predetermined distances all being shorter than the critical length for the print wire to prevent buckling. The predetermined positions at which the guide plates are mounted are also both within one-eighth wave-length of the peak deflection points of a print wire when the wire is vibrating at its natural frequency of vibration. For a preferred embodiment of the invention, the print head is of the type having a single column of n print wires and the print guide member has its n openings alined one on top of the other, there being a predetermined spacing between adjacent openings. The nonprinting ends of the wires are mounted with one wire in the middle and the other (n-1) wires substantially symmetrically positioned around the one wire with the angular spacing between adjacent wires being substantially equal. The guide plates each have a center opening through which one wire passes, and (n-1) other openings positioned around the center opening through a separate one of which each of the other (n-1) wires passes. The spacing of each of the openings from the corresponding center opening is a function of the natural deflection of the print wire passing therethrough at the predetermined position of the guide plate.