JPH0721327Y2 - Wire dot print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a structure of a wire dot print head used in a serial printer. (Prior Art) Conventionally, various types such as a plunger type, a spring charge type, and a clapper type have been provided as wire dot print heads that perform printing by driving a print wire.

Generally, a spring charge type wire dot print head has an armature having a print wire fixed to a bias leaf spring, and the leaf spring is swingably supported by a first support member and a second support member. Further, the core around which the coil is wound is arranged on the same side as the second support member so as to face the armature. Then, the magnetic flux of the permanent magnet that circulates the armature and the core attracts the armature to the core to bend the leaf spring and store the energy required for rocking. During printing, the coil is excited to cancel the magnetic flux of the permanent magnetic flux, the armature is released from the core, and the printing wire is swung to perform printing.

The spring-charged wire dot print head disclosed in Japanese Patent Laid-Open No. 2-117842 by the present applicant is a type suitable for high speed, and the height of the leaf spring supporting surface of the second yoke as the second supporting member is The height is lower than the height of the armature suction surface of the core, and a predetermined step is provided between the core and the second support member for storing energy required to swing the bias leaf spring. It also includes a sub-core provided on the core side to reduce magnetic interference.

By the way, the armature suction surfaces of the core and the sub core and the second
When the leaf spring support surface of the support member is ground, the second support member side is incorporated into the base of the print head to which the core and the sub core are fixed, and the armature suction surface and the leaf spring support surface are ground. At this time, in order to provide a predetermined step between the armature suction surface and the leaf spring support surface, a shim having a predetermined step thickness is sandwiched on the second support member side so that the spring support surface is made into the armature suction surface. It is made higher and grinding is performed. After grinding, the shim was removed to provide a predetermined step between the spring support surface and the armature suction surface.

(Problems to be solved by the invention) In the conventional wire dot print head, when the armature suction surface of the core and the sub core and the leaf spring support surface of the second support member are ground, the leaf spring support surface is removed. To make it lower than the armature suction surface, insert a shim on the side of the second support member and fix it with a screw to the base of the print head with the core and sub-core fixed. After grinding, loosen the screw and remove the shim, and then screw again. Since it was tightened, there was a problem that the assembly accuracy deteriorated.

Further, there is a problem that the number of assembling steps increases because the steps of fixing, grinding, removing the shim, and re-fixing are performed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wire dot print head that does not require reassembly after grinding of the spring support surface of the second support member and the armature suction surfaces of the core and the sub core.

(Means for Solving the Problem) In order to achieve the above object, in the wire dot print head of the present invention, the armature suction surface of the core and the leaf spring support surface of the second support member are flush with each other, and A bias leaf spring is provided at the end of the leaf spring supporting surface of the first support member, and a convex portion for elastically deforming is provided on the first support member side.

(Operation) Second of the wire dot print head configured as described above
When the bias leaf spring is held between the support member and the first support member, the bias leaf spring is pushed toward the second support member side by the convex portion provided on the first support member. by the way,
Since the leaf spring support surface of the second support member and the armature attraction surface of the core are flush with each other, the bias leaf spring is elastically deformed at the unconstrained portion between the leaf spring support surface and the armature attraction surface. In this state, the armature fixed to the bias leaf spring is attracted to the core and comes into close contact with the attraction surface of the core. Therefore, the unconstrained portion of the bias leaf spring is bent into an S-shape, and the energy required for printing is stored. To be

Therefore, according to the present invention, it is not necessary to loosen the screw fixing the second supporting member side after grinding the spring supporting surface of the second supporting member and the armature suction surfaces of the core and the sub core.

(Embodiment) An embodiment of the present invention will be described with reference to the drawings. The elements common to the drawings are given the same reference numerals.

FIG. 1 is a partial sectional view of a wire dot print head according to an embodiment of the present invention. The base 9 has a first yoke 8,
The permanent magnet 7, the second yoke 6, the bias leaf spring 3 (hereinafter referred to as the leaf spring 3), the spacer yoke 5, and the armature yoke 4 are laminated, and the base 9, the first yoke 8, the permanent magnet 7, and the second magnet The yoke 6 is fixed with screws 15, and the second yoke 6, the leaf spring 3, the spacer yoke 5, and the armature yoke 4 are fixed with screws 18. The base 9, the first yoke 8, the permanent magnet 7, the second yoke 6, and the spacer yoke 5 are annular. The leaf spring 3 is circular and has a plurality of tongues 3a radially toward the center. An armature 2 having a printing wire 1 at the tip is fixed to each tongue piece 3a of the leaf spring 3. The armature yoke 4 is circular and has a radial shape toward the center through which the armature 2 escapes. A core 10 around which a coil 11 is wound and a sub core 12 are radially arranged so as to face each armature 2 and are erected on a base 9. Armature suction surfaces (hereinafter referred to as suction surfaces) of the core 10 and the sub core 12 are covered with a wear-resistant metal sheet 16. Core 10 and secondary core 12
At the time of grinding, the attraction surface of the second yoke 6 and the supporting surface of the leaf spring 3 of the second yoke 6 are arranged in the order of the first yoke 8, the permanent magnet 7, and the second yoke 6 on the base 9 to which the core 10 and the sub core 12 are fixed. Are laminated, fixed with screws 15, and ground to the same height. As shown in FIG. 3, the spacer yoke 5 is provided with a convex portion 5a formed by press working along the inner periphery thereof, and each tongue piece of the leaf spring 3 is provided.
The base of 3a is pressed in the direction of arrow B. Therefore, each tongue piece 3a is in contact with the peripheral edge portion of the suction surface of the opposing sub core 12. A head substrate 14 is provided on the back surface of the base 9 via an insulating rubber packing 13, and the terminals of the coil 11 are soldered to the coil terminal attachment portions of the head substrate 14.

Next, the operation will be described separately for non-printing and printing.
FIG. 2 is an enlarged cross-sectional view of the vicinity of the bias leaf spring during non-printing. The magnetic flux of the permanent magnet 7 is circulating as shown by the circular arrow 17 in FIG. 1, and the armature 2 is in close contact with the attracting surfaces of the core 10 and the sub core 12 through the metal sheet 16 almost in parallel. Therefore, each tongue piece 3a of the leaf spring 3 is necessary for the unconstrained portion between the suction surface of the sub-core 12 and the leaf spring support surface of the second yoke to curve and swing in the direction of arrow B. Energy is stored.

On the other hand, at the time of printing, the circuit of the head substrate 14 is activated, so that the coil 11 is excited for a short time and the permanent magnet 7 is applied to the core 10.
Magnetic flux is generated so as to cancel the magnetic flux of. As a result, the armature 2 is released from the attraction force of the core 10, and the leaf spring 3
The printing wire 1 operates in the direction of arrow A by the energy stored in, and dot-prints on paper or the like via an ink ribbon (not shown). Explaining the role of the sub core, in addition to the function as a supporting member for bending the leaf spring as described above, it imposes a function of reducing magnetic interference generated when the adjacent print wires are simultaneously driven. There is.
That is, the magnetic flux generated in one of the adjacent coils flows into the other core, and flows into the sub core so as not to act as a counter electromotive force in the other coil.

In the present embodiment, the spacer yoke is provided with a convex portion as a convex portion, but as shown in FIG.
May be provided by pressing. In this case, concentrated stress is not applied to the leaf spring as compared with the convex portion, so that the life of the leaf spring is extended.

Compared with the conventional technology, the present invention has an increased number of pressing steps for providing a convex portion on the spacer yoke, but the grinding time in the grinding step may be short, and the man-hours for removing the shim and re-fixing are unnecessary. As a result, the man-hours as a whole are reduced.

(Effects of the Invention) Since the present invention is configured as described above, it has the following effects.

When grinding the suction surface of the core and the leaf spring supporting surface of the second supporting member flush with each other, the shim is sandwiched on the second supporting member side, and after grinding, the screw is loosened to remove the shim. Assembling accuracy is improved because no process is required.

Further, since the steps of removing the shim and re-adhering are not necessary, the number of assembling steps is reduced, and an inexpensive wire dot printing head can be provided.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a wire dot print head according to the present invention, FIG. 2 is an enlarged sectional view in the vicinity of a leaf spring for bias when not printing, and FIG. 3 is a side view of a space yoke including the partial sectional view. FIG. 4 is an enlarged sectional view showing a modified example. 1 ... Print wire, 2 ... Armature, 3 ... Bias leaf spring, 5,19 ... Spacer yoke, 5a ... Convex part, 6
...... Second yoke, 7 ... Permanent magnet, 10 ... Core, 11 ...
… Coil, 19a… Inclined part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Iwao Hashimoto 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) Reference JP-A-58-171973 (JP, A) JP-A-SHO 61-123547 (JP, A) JP-A-63-276558 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A bias leaf spring having an armature fixed thereto is sandwiched between a first supporting member and a second supporting member in a cantilevered manner, and is arranged on the same side as the second supporting member facing the armature. The permanent magnet's magnetic flux passing through the core and the armature attracts the armature to the attraction surface of the core to bias the bias leaf spring, excites the coil wound around the core, cancels the permanent magnet's magnetic flux, and releases the armature. In a wire dot printing head for dot printing with a printing wire, the suction surface of the core and the leaf spring support surface of the second support member are flush with each other, and the leaf spring support surface end portion of the first support member is provided. A wire dod print head, characterized in that a convex portion for elastically deforming the bias leaf spring is provided on the side of the first supporting member.