Abstract: An electromagnetic actuating device includes an armature, which has a permanent magnet and can move along a longitudinal axis between actuation positions relative to a stationary coil and in reaction to energization, armature has an engagement section for interacting with a plunger, and which armature can move from a first actuation position, which is stable in the currentless state, into a second actuation position against a restoring force of a spring, wherein the coil has a first coil unit, which acts on the armature and which releases the armature from the first actuation position, wherein the coil has a second coil unit which, during movement, applies to the armature a force which accelerates the armature, and wherein the coil has a restoring coil such that when the armature is returned from the second into the first actuation position, the restoring coil boosts the restoring force of the spring.

Abstract: In order to realize a weight saving and prevent a concentration of stress to thereby obtain durability endurable for high-speed printing, an armature of the present invention has an arm that is formed into a long-sized plate-like shape and holds a printing wire at its end section and a magnetic circuit forming member that is positioned at the other end at the side of the printing wire and has a projecting section projecting from the arm toward the direction in which the printing wire extends, wherein a first inclined surface that gradually inclines toward the projecting section in the direction in which the printing wire extends and a concave-shaped first curved surface that communicates with the first inclined surface and bends inward with a predetermined curvature to reach the projecting section are formed at a first end face of the arm at the side of the projecting section.

Abstract: In order to obtain joining force endurable for high-speed printing and realize an enhancement in magnetic characteristic, a plate-like arm for supporting a printing wire is laminated with a magnetic circuit forming member that is composed by laminating plural plates for forming a magnetic circuit, wherein a weld zone is formed on the laminated surface of the arm and plates with laser beam irradiation for fixing the arm and the magnetic circuit forming member with the weld zone.

Abstract: A wire dot printer head of the present invention has an armature that has an arm supporting a printing wire and pivotably provided at the position opposite to the core, and a coil spring that one end comes in contact with the arm for urging the armature in the direction away from the core, wherein the one end of the coil spring supported by the supporting member is brought into contact with the armature to apply return force to the armature. In order to prevent the breakdown of the armature due to a contact of the coil spring and to realize a stabilized urging operation of the coil spring, a winding end of the coil spring at the one end is located at the position inside of the coil spring and nearer to the supporting member from the contact position where the coil spring comes in contact with the armature.

Abstract: A wire dot printer head which has an armature spacer having plural notches accommodating support shafts of plural armatures respectively supporting a printing wire, and an abrasion preventive member provided between the armature spacer and a yoke holding the support shafts of the plural armatures with the armature spacer for prevention of contact between the support shafts of the plural armatures and the yoke. As the support shafts of the armatures, protected by the abrasion preventive member, are not in direct contact with the yoke, abrasion of the surface of the yoke can be suppressed, and degradation of printing quality can be prevented.

Abstract: A wire dot printer head which has an armature spacer having plural notches accommodating support shafts of plural armatures respectively supporting a printing wire, and an abrasion preventive member provided between the armature spacer and a yoke holding the support shafts of the plural armatures with the armature spacer for prevention of contact between the support shafts of the plural armatures and the yoke. As the support shafts of the armatures, protected by the abrasion preventive member, are not in direct contact with the yoke, abrasion of the surface of the yoke can be suppressed, and degradation of printing quality can be prevented.

Abstract: A needle guide (5) is composed of a first guide wall (5a) and a second guide wall (5b) arranged at a distance x from each other. Each of these guide walls is formed with through holes through which needles penetrate and which extends parallel to the longitudinal direction of a needle bunch, the through holes of the first guide wall and the second guide wall for one needle is shifted from each other in the convergence direction of the needles with a shift amount ?n determined by the distance x and a convergence angle ?n of the needle.

Abstract: In the wire dot printer head and wire dot printer of the present invention, a plurality of armatures are rockably mounted in positions corresponding to a plurality of cores. On the end face on the core side of a wire, a plurality of receiving members are provided. And a plurality of pressing members for pressing the armature to move away from the core are mounted in contact with these receiving members. The receiving member therefore can prevent the pressing member from damaging to break the armature.

Abstract: In order to restrain a flux loss for obtaining magnetic characteristic required for high-speed printing, a wire dot printer head has armature 4 having a pivot shaft serving as a center of a pivot and pivotably provided so as to oppose to plural cores formed on a yoke and an armature spacer provided on the yoke for forming a side magnetic path with respect to the armature, wherein, supposing that each of the saturated magnetic fluxes of the yoke, the armatures and the armature spacer is defined as A, B and C in this order, these components are formed to establish a relationship of A?B?C.

Abstract: In an impact dot print head there is provided a fitting structure for fitting an inner periphery-side cylindrical portion of a yoke and an inner periphery-side ring-shaped portion of an armature spacer with each other so that the inner periphery-side cylindrical portion of the yoke and the inner periphery-side ring-shaped portion of the armature spacer push against each other, thereby permitting a magnetic flux to flow efficiently between the armature spacer and the yoke through the contact face between the inner periphery-side cylindrical portion of the yoke and the inner periphery-side ring-shaped portion of the armature spacer.

Abstract: An impact printer with a hammerbank having print hammers retained by a permanent magnet for impacting a print ribbon, and a mechanical driver for moving the hammerbank across print media. First and second coils for each hammer are wrapped around first and second pole pieces, one of which is asymmetrical to the other pole piece. One of the pole pieces can have a generally elongated longitudinal form with the coil wound around the longitudinal form and the other can have a generally arcuate form, with the coil wrapped on a portion between the ends thereof. The coil wrapped around the arcuately formed pole piece is thicker than the coil wrapped around the longitudinal pole piece. The result is to provide pole pieces and coils for an impact printer having differing spatial relationships that can be staggered, or formed asymmetrically for more compact coil and pole piece placement to improve printer efficiency.