JPS6381056A - Dot printer head - Google Patents

Abstract

PURPOSE:To realize high-speed operation and cost reduction by dividing an auxiliary yoke into upper and lower yoke pieces one each with a leaf spring with the lower yoke piece extended to the middle of an armature and the upper yoke piece extended to the inner end of the armature, and connecting counter-facing parts which are positioned to both sides of the armature which one yoke does not face, to the tip of the yoke in a continuous manner. CONSTITUTION:A yoke piece 6 below a leaf spring 8 extends to the middle of an armature 9, and a slightly broader notch 6a than the armature 9 is formed in the tip center of the armature. The upper yoke piece 7 stretches to the inner end of the armature 9 and the counter-facing parts 7a, 7a positioned to both sides of the armature 9 which one yoke piece 6 does not face, are connected to the tip of the armature. As a result, a space formed by the notch 6a and counter-facing parts 7a, 7a provides an armature receiving part 5a, and this part is in turn connected to a magnetic space g2 which exists between an auxiliary yoke 5 and the edge of an inner leg piece 2a. A magnetic flux is transferred between an a face forming the armature receiving part 5a and the side of the armature 9. Consequently, a high-speed operation is assured and the cost is reduced because of the ability to weld the armature 9 to an integrally formed leaf spring 8 using laser.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a dot printer head that performs printing by controlling the excitation of coils in a plurality of radially arranged magnetic paths and displacing an armature to which a printing wire is fixed. Regarding.

[Background Art] One of the plurality of magnetic paths arranged radially in parallel in this type of dot printer head is one shown in Figs. 6 and 7. That is, one magnetic path is formed by a yoke B around which a coil A is wound and an auxiliary yoke C with a magnetic gap interposed therebetween and a permanent magnet E interposed therebetween. F is an armature that is fixed to the tip of a leaf spring G whose base end is fixed, and is disposed movably within the armature housing portion H of the auxiliary yoke connected to the magnetic gap of each magnetic path, and is Printing wire L
It is fixed. The auxiliary yoke C of this one is a leaf spring G
A facing portion Ca facing both sides of the armature F is continuously provided at the tip (inner side) of the armature F. In this case, since the distance between the facing parts Ca and Ca is small, the leaf spring G
is fixed by brazing to the outer end of the armature F where the facing portion Ca does not exist. If the leaf spring were to be extended to the inner end of the armature F and laser welded, the width of that part would be narrow (usually about 2IIlffi), so it would be in a hardened state, making it brittle and lacking in fatigue strength. In addition, when brazing is used, it is difficult to use an integrated leaf spring, and an independent individual leaf spring must be used for each magnetic path, which is disadvantageous in terms of cost.

On the other hand, there is also a device as shown in FIGS. 9 and 10, which uses an integrated leaf spring G and has an armature F laser welded thereto. The auxiliary yoke C of this one is located below the leaf spring G, and its tip (inner) portion extends to the inner end of the armature F.

In this case, the inside of the leaf spring G can be sufficiently wide without being restricted by the auxiliary yoke C, so that the laser welding will not result in hardening during the hit. However, when focusing on the thickness of the auxiliary yoke G, there is a restriction that it cannot be thicker than the armature F. Therefore, if the magnetic path area of the auxiliary yoke G is to be increased, the thickness of the armature F must be increased.

Dot printer heads are required to operate at high speed and at low cost. Regarding the former, it is generally necessary to increase the magnetic attraction force to the armature and to reduce the weight of the movable member including the armature. For the latter, it is advantageous to use an integral leaf spring to which the armature is laser welded. In such a case, there is a limit to the ability of conventional devices to satisfy such requirements.

OBJECT OF THE INVENTION] The present invention has been made in view of the above points, and its purpose is to provide a dot printer head that operates at high speed and is inexpensive.

[Disclosure of the Invention] In the dot printer head of the present invention, the auxiliary yoke is attached to the upper and lower parts of the leaf spring to which the armature is fixed, with a predetermined gap therebetween.
One yoke piece located below the leaf spring is extended to the middle part of the armature, the other yoke piece located above the leaf spring is extended to the inner end of the armature, and one The yoke piece of the armature is characterized in that a facing part that faces both sides of the armature that does not face the yoke piece is connected to the tip of the armature.

According to the present invention, since the magnetic path area of the auxiliary yoke can be ensured sufficiently, the magnetic attraction force to the armature can be increased, and since there is no need to make the armature thicker, its weight can be reduced, and therefore, it can operate at high speed. Furthermore, since an integrated leaf spring is used and the armature can be laser welded to it, the cost is low.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 5.

1 is one magnetic path of the dot printer head, and a plurality of these magnetic paths are arranged radially in parallel. Reference numeral 2 denotes a yoke, which has a U-shaped cross section with the inner and outer leg pieces 2a and 2b and the connecting piece 2C;
b is cylindrical and integrally formed. A plurality of inner leg pieces 2a (usually 9 or 24 pieces) are arranged radially at equal intervals, and are either integrally formed with the yoke 2 or attached to the connecting piece 2.
Press-fit and fix in C. The coil 3 is wound around each inner leg piece 2a. The permanent magnet 4 has a ring shape and is placed and fixed on the end surface of the outer leg piece 2b of the yoke 2.

Reference numeral 5 denotes an auxiliary yoke consisting of one yoke piece 6 and the other yoke piece 7, both of which are ring-shaped as a whole, and portions forming each magnetic path extend inward. One yoke piece 6 is placed and fixed on the permanent magnet 4, and the other yoke piece 7 is placed and fixed thereon via a leaf spring 8, which will be described later, with a predetermined gap g1 between each yoke piece. do. In other words, the auxiliary yoke 5 is divided into two upper and lower yoke pieces 6.7 with a predetermined gap g1 interposed therebetween. A more detailed explanation will be given later.

As shown in Fig. 3, the leaf spring 8 is ring-shaped as a whole, and the portion corresponding to each magnetic path extends to the inner leg piece 2a near the end of the inner leg 2a. A narrow portion 8a is formed which is shorter than the length in the radial (longitudinal) direction of the armature 9, which will be described later, and is substantially the same as the armature 9.

The armature 9 has a substantially rectangular parallelepiped shape with a thin wall on the inner side, and is laser welded to the leaf spring 8 at a portion spanning a narrow portion 8a and a wide portion 8b, as shown in FIG.

Further, a printing wire 1) is fixed to the inner end via an arm 10.

Next, the auxiliary yoke 5 will be described in detail with reference to FIGS. 4 and 5. One yoke piece 6 located below the leaf spring 8 extends to the middle part of the armature 9, and has a cutout part 6a slightly wider than the armature 9 formed at the center of the tip. Further, the other yoke piece 7 located above the leaf spring 8 extends to the inner end of the armature 9, and the one yoke piece 7
A facing portion 7a facing both sides of the armature 9 that does not face the
.

7a is connected to its tip. These facing parts 7a, 7a
The interval is approximately equal to the width of the cut portion 6a.

As a result, the space formed by the cutout part 6a and the facing parts 7a, 7a becomes the armature accommodating part 5a, and this is the space formed by the auxiliary yoke 5.
and a magnetic gap g2 interposed between the end faces of the inner leg pieces 2a.

The armature 9 is disposed movably within the armature accommodating portion 5a, and magnetic flux is exchanged between the surface forming the armature accommodating portion 5a and the three side surfaces of the armature 9.

Therefore, the yoke 2 with the coil 3 wound thereon and the auxiliary yoke 5
1 with a magnetic gap g2 and a permanent magnet 4 inserted.
A magnetic path is formed, and a plurality of magnetic paths are arranged radially in parallel, and these are housed in a housing (not shown).

In such a dot printer head, when the coil 3 is demagnetized, the armature 9 resists the full spring force of the leaf spring 8 due to the magnetic attraction force (magnetic flux) of the permanent magnet 4, and the inner leg piece 2 of the yoke
It is attracted to the a end face.

Then, when the coil 2 is excited, the magnetic flux of the coil 3 cancels out the magnetic flux of the permanent magnet 4, and therefore the armature 9
As shown in the figure, the printing wire 1) is released from suction by the full spring force of the leaf spring 8, and prints on the paper on the platen (not shown). In this movement, both yoke pieces 6.7 are pressed against the leaf spring 8.
The above-mentioned predetermined gap g1 is required to provide a sufficient gap that does not interfere with the displacement operation of the .

The dot printer head with such a configuration has both yoke pieces 6.
7 are arranged above and below the leaf spring 8, the magnetic path area of the entire auxiliary yoke and the area facing the armature 9 can be increased.
Therefore, the magnetic attraction force to the armature 9 can be increased.

Moreover, in order to do so, it is not necessary to increase the volume of the armature 9 at all, and it is possible to make the volume of the armature 9 smaller than the conventional one, so that the armature 9 can be made lighter. On the other hand, since only the facing portions 7a, 7a of the other yoke piece 7 restrict the width of the leaf spring 8, a wide portion 8b can be provided at the armature fixing portion of the leaf spring 8. 8 can be integrated and laser welded.

[Effects of the Invention] In the dot printer head of the present invention, the auxiliary yoke is attached to the upper and lower parts of the leaf spring to which the armature is fixed, with a predetermined gap therebetween.
One yoke piece located below the leaf spring is extended to the middle part of the armature, the other yoke piece located above the leaf spring is extended to the inner end of the armature, and one Since the facing part facing both sides of the armature that the yoke pieces do not face is connected to the tip of the armature, the magnetic path area of the auxiliary yoke can be secured sufficiently, so the magnetic attraction force to the armature can be increased, and the armature Since there is no need to increase the thickness of the armature, it can be made lighter, which increases the speed of operation.Furthermore, since an integrated leaf spring is used and the armature can be laser welded to this, the cost is reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing an embodiment of the present invention.
FIG. 3 is a plan view of the leaf spring; FIG. 4 is a perspective view of the main parts; FIG. 5 is an exploded perspective view thereof; FIG. 6 is a conventional example. 7 is a perspective view of the main part, and FIG. 8 shows the fixed part of the leaf spring and armature.
= A perspective view, FIG. 9 is a sectional view of another conventional example, and FIG. 10 is a perspective view of the main part thereof. 1-...1 magnetic path of dot printer head, 2--yoke, 3--coil, 4--permanent magnet, 5 (6,7)--
- Auxiliary yoke, 5a--armature accommodating section, 6--one yoke piece, 7-other yoke piece, 7a one facing part, 8-
Leaf spring, 9 - armature, 1) - printing wire, gl -
・Predetermined gap, g2・−magnetic gap.

Claims (1)

[Claims] (1) The yoke around which the coil is wound and the auxiliary yoke form one magnetic path with a magnetic air gap and a permanent magnet inserted;
A plurality of magnetic paths are arranged radially in parallel, and an armature fixed to the tip of a leaf spring whose base end is fixed is disposed movably within an armature housing portion of an auxiliary yoke connected to the magnetic gap of each magnetic path, Moreover, in a dot printer head in which a printing wire is fixed to the armature, the auxiliary yoke is divided into two upper and lower yoke pieces with a predetermined gap interposed between them with respect to the leaf spring, and one of the yoke pieces is located below the leaf spring. A facing part in which a yoke piece extends to the middle part of the amphitheater, the other yoke piece located above the leaf spring extends to the inner end of the amphitheater, and faces both sides of the amphitheater that the one yoke piece does not face. A dot printer head characterized by having a series of .