Patent ID: 7314323

Claim:
A wire dot printer head comprising: a plurality of armatures, each of which supports a printing wire and has a support shaft as a rotational center; a yoke comprising an outer peripheral cylindrical member, an inner peripheral cylindrical member, a plurality of cores provided between the outer peripheral cylindrical member and the inner peripheral cylindrical member, and a coil wound around each of the plurality of cores, the yoke supporting the support shafts of the plurality of armatures at the outer peripheral cylindrical member such that each of the plurality of armatures is positioned opposite to a respective one of the plurality of cores; and an abrasion prevention plate provided between the yoke and the plurality of armatures to prevent contact between the support shafts of the plurality of armatures and the yoke; wherein the abrasion prevention plate is ring shaped and has a substantially constant thickness in an axial direction thereof, the abrasion prevention plate has an outer diameter that is substantially the same as an outer diameter of the outer periphery cylindrical member of the yoke, and the abrasion prevention plate has an inner edge that is disposed outside of the cores in a radial direction of the abrasion prevention plate; wherein the abrasion prevention plate comprises a plurality of abrasion resistant contact prevention members which are positioned between the yoke and the support shafts of the plurality of armatures; and wherein the abrasion prevention plate has a magnetic permeability such that the abrasion prevention plate forms a part of a magnetic path with the cores, and is shaped so as not to disturb oscillation of the plurality of armatures.