Abstract: Lift of the rotation fulcrum of the armature is prevented. In the print head in which a print wire is furnished at an end portion, and that has an armature that is furnished rotatably, a yoke touches a rotation fulcrum of the armature; an elasticity member of a cantilever structure presses the rotation fulcrum of the armature to the yoke by sandwiching the armature between the yoke and the elasticity member; a housing fixes an end portion of the elasticity member and covers the elasticity member through forming a gap between the elasticity member and the housing; and a pressing member is arranged between the housing and the elasticity member and touches the housing and the elasticity member.

Abstract: According to a dot head of the invention, an armature structure for moving a printing needle forward and backward has the efficiency that the magnetic characteristics is excellent and mechanical intensity is high. The armature structure is manufactured in a manner that an arm member, which is formed by subjecting a plate-shaped material excellent in abrasion resistance performance and having a high intensity to a plating processing using born etc., is sandwiched at a portion thereof from both sides in a stacked manner by two armature members each of which is formed by subjecting a plate-shaped material excellent in magnetic characteristics to a plating processing using born etc. A pin formed by subjecting a piano wire to a plating processing using boron etc. is inserted with a small pressure into common through holes of the two armature members and the arm member thus stacked thereby to provisionally assemble them.

Abstract: An appropriate gap between a yoke plate and a print lever is to be continuously maintained. A gap spacer (24) is inserted between a yoke plate and a print lever (14a). The print lever (14a) abuts a print-lever abutting portion (24b) of the gap spacer (24) in performing printing on a print surface. The gap spacer (24) is provided with notches (24a), so that nine print-lever abutting portions (24b) are separated and independent from one another. Therefore, even if hitting impact is constantly applied from the print lever (14a), no wrinkle is formed in the gap spacer (24), and an appropriate gap between the yoke plate and the print lever (14a) can be appropriately maintained.

Abstract: An armature structure according to the present invention is arranged in a manner that two armature members, in each of which a shear plane and a broken-out section are formed by a punching processing on an inner periphery of a through hole into which a fulcrum shaft fits, are joined integrally in a state of sandwiching an arm therebetween so as to position the broken-out sections of the armature members at the outer side. Thus, even by the rotation of the armature structure during a printing operation, there does not arise a problem that the armature structure inclines due to eccentric wear, so that a stable printing state can be obtained for a long term.

Abstract: In order to realize a stable rocking operation of the armature for performing high-speed printing, between the armature spacer for accommodating and holding the support shaft of the armature which supports the printing wires, and the yoke for holding the support shafts of the plurality of armatures together with this armature spacer, there is provided the abrasion preventing member formed of material having higher magnetic permeability than that of the yoke, and hardened by surface hardening processing.

Abstract: An armature damper according to the present invention acts to abut against the arm of an armature to stop the arm at a predetermined backward position. The armature damper is formed in a manner that the surface thereof abutting against the arm is formed by a rigid body member and an elastic member is integrally joined to the rear surface of the rigid body member, and the elastic member is formed to protrude from the outer side of the rigid body member at least at the engaging portion between a positioning armature stopper and the armature damper. The protruded portion is used as a buffer at the engaging portion between the armature stopper and the armature damper.

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: In order to realize a stabilized pivotal movement of an armature to thereby obtain pivotal force required for high-speed printing, a pivot shaft is held such that an armature having an attracted face that is in contact with a core, that has a coil wound therearound and has a pole face, and the pivot shaft is opposed to the core, whereby the armature becomes pivotable. An attracting direction of attraction force F acted on the attracted face by the core and the moving direction in which the attracted face moves due to the attraction force F are made substantially equal to each other.

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: An armature manufacturing method of forming an armature including an arm holding a printing wire, and magnetic circuit forming members attached to the arm places the magnetic circuit forming members on the arm with a resistive layer of a resistive material having high electric resistance sandwiched between the arm and each of the magnetic circuit forming members, and welds together the arm and the magnetic circuit forming members with the resistive films sandwiched between the arm and the magnetic circuit forming members by spot welding. The arm and the magnetic circuit forming members of the armature can be joined together by welds having a high weld strength.

Abstract: In order to realize a stable rocking operation of the armature for performing high-speed printing, between the armature spacer for accommodating and holding the support shaft of the armature which supports the printing wires, and the yoke for holding the support shafts of the plurality of armatures together with this armature spacer, there is provided the abrasion preventing member formed of material having higher magnetic permeability than that of the yoke, and hardened by surface hardening processing.

Abstract: In order to enhance magnetic characteristic to realize a stabilized pivotal movement of an armature and to obtain magnetic characteristic required for high-speed printing, an armature according to the present invention has a magnetic circuit forming member formed by laminating plural plates to be provided on an arm, that supports a printing wire, for forming a magnetic circuit.

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: A wire dot printer head of the present invention is configured by being provided with an abrasion preventive member which surrounds an outer circumference of support shafts of a plurality of armatures, between an armature spacer having a plurality of cutouts for respectively accommodating the support shafts of the plural armatures that respectively support printing wires, and a yoke which holds the support shafts of the plural armatures with the armature spacer. With this structure, the support shafts of the armatures do not directly contact with the yoke owing to the abrasion preventive member, thereby restraining abrasion of a surface of the yoke, and preventing a deterioration of printing quality.

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.

Abstract: A wire dot printer head of the present invention is provided with an abrasion preventive member in a yoke. The abrasion preventive member encloses the outer periphery of the armature support shafts. The yoke, together with an armature spacer having a plurality of cutouts for holding the armature support shafts, holds the armature support shafts. The armature support shafts do not directly contact the yoke because of the use of the abrasion preventive member. It is therefore possible to restrain abrasion of the yoke surface and accordingly to prevent deterioration in printing quality.

Abstract: In the impact dot print head of the present invention there is used an armature spacer having side yoke portions which extend away from cores of a yoke and confront armatures. With such an armature spacer, when a magnetic circuit is formed by a magnetic flux generated by a coil which circuit passes from the associated core in the yoke, then through to-be-attracted members and the armature spacer successively, and reaches the yoke, the magnetic flux generated by the coil is prevented from flowing directly from the core to the armature spacer without flowing through the armature, whereby it is made possible to form a satisfactory magnetic circuit which permits the magnetic flux generated by a coil to flow from the associated core to the armature spacer through the associated to-be-attracted members.

Abstract: In the wire dot printer head of the present invention, there is provided an armature stopper against which an armature having pivoted from a printing position to a stand-by position comes into abutment, the armature stopper being formed by bonding an elastic plate and a hard plate with each other into an integral combination and thereafter punching the integral combination from the hard plate side. By this punching work the armature stopper is warped so that the hard plate side is convex in shape. With this warp, when the armature having pivoted to the stand-by position comes into abutment against the armature stopper, the armature stopper deflects in a direction to eliminate the warp. With this deflecting motion, an impact force induced upon mutual abutment of the armature and the armature stopper is diminished and deformation or chipping of the hard plate are suppressed, further, the durability of the armature stopper is improved and the printing accuracy is kept high over a long period.

Abstract: In the wire dot printer head of the present invention, an armature adapted to move pivotally between a printing position and a stand-by position is provided with a pivot shaft serving as a fulcrum, and the pivot shaft is pinched and supported by a pair of support members from both sides in the pivoting direction of the pivot shaft. In at least one support member is formed a concave support groove into which an outer periphery surface of the pivot shaft is inserted in a state of surface contact with the groove. When the armature moves pivotally in a printing operation, the surface of contact increases because the pivot shaft and the pivot groove are in surface contact with each other, thus preventing the occurrence of a local concentration of a strong force on the contact portion between the pivot shaft and the support groove.