JPS6381057A - Dot printer head - Google Patents

Abstract

PURPOSE:To enable high-speed operation by extending a ring-shape leaf spring with a spring part matching each magnetic course inwardly and forming a strip which is almost as wide as an armature on the tip of the spring part within a shorter range than the radial length of the armature. CONSTITUTION:A dot printer head has a totally ring-shaped spring part 9a matching each magnetic course formed as part of a leaf spring 9 extending inwardly, with the tip of the spring part 9a forming a strip 9b which is almost as wide as an armature 10 within the shorter range than the radial length of the armature 10. An auxiliary yoke 5 is arranged in the form of three yoke pieces on the upper and lower sides of the leaf spring 9. Further, opposite faces (including counter pieces of an auxiliary yoke piece 8a) are continuously installed in such a way as to hold a strip 9a of the leaf spring 9 and the side of the armature 10 on the tips of the second yoke 7 of each yoke piece and the auxiliary yoke piece 8a of the third yoke piece 8. Consequently, the magnetic course area of the auxiliary yoke 5 can be enlarged, and the opposite areas of the auxiliary yoke 5 and the armature 10 increased. Thus the high-speed operation of the dot printer head is achieved.

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. 5 and 6. 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 the spring part of a leaf spring G whose ring-shaped base end is fixed, and is disposed movably within the armature housing part H of the auxiliary yoke that connects to the magnetic gap of each magnetic path. The printing wire L is fixed via J. 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 addition, the leaf spring G is
The width is approximately equal to the width of the auxiliary yoke C, and is sufficiently larger than the width of the armature F. As a result, even if the armature F is fixed to the leaf spring G by laser welding, the leaf spring G will not be in a hardened state during the hit, and sufficient elasticity can be maintained.

However, if we focus on the thickness of the auxiliary yoke C, the auxiliary yoke C has approximately the same width as the leaf spring G and is arranged in an overlapping manner. Thickness is limited.

By the way, when trying to speed up the dot printer head,
Generally, it is necessary to increase the magnetic attraction force to the armature and to reduce the weight of the movable member including the armature. However, in the above-mentioned conventional device, when trying to increase the magnetic path area of the auxiliary opening C and the area facing the armature F in order to increase the magnetic attraction force, the thickness of the armature F has to be increased. Since the amateur FIJ becomes heavier, it has been difficult to increase the speed in this manner.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to
To provide a dot printer head capable of increasing the speed of operation by increasing the magnetic path area of an auxiliary yoke and the opposing area between the auxiliary yoke and an armature.

[Disclosure of the Invention] In the dot printer head of the present invention, the leaf spring is formed into a ring shape as a whole, and the spring portion corresponding to each magnetic path extends inward, and the tip of the spring portion is It is characterized in that a narrow portion approximately equal to the width of the armature is formed in a range shorter than the radial length of the armature.

According to the present invention, the magnetic path area of the auxiliary yoke is increased by dividing the auxiliary yoke into at least two yoke pieces above and below the leaf spring without increasing the size of the armature. The narrow width portion and the opposing facing portions are connected to each other so as to sandwich the side surfaces of the armature, thereby increasing the opposing area between the auxiliary yoke and the armature, thereby increasing the speed of operation of the dot printer head.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

(2) 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 (if! usually 9 or 24 pieces) are arranged radially at equal intervals, and are either integrally formed with the yoke 2 or press-fitted into the connecting piece 2C. 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.

5 is one of the first. An auxiliary yoke consisting of second yoke pieces 6, 7 and the other third yoke piece 8, both of which are ring-shaped as a whole, and the portions forming each magnetic path extend to near the inner end of the inner leg piece 2a. are doing.

The first yoke piece 6 is placed and fixed on the permanent magnet 4, the second yoke piece 7 is placed and fixed on the first yoke piece 6, and the third yoke piece 8 is placed thereon via a leaf spring 9, which will be described later. A predetermined gap g1 exists between the second yoke piece 7 and the third yoke piece 8. Of course, the first yoke piece 6 and the second yoke piece 7 may be integrally molded using lost wax (precision casting), etc.
From the viewpoint of manufacturing cost, it is more advantageous to make each yoke piece thinner and manufacture it by press working. The shape and the like in relation to the leaf spring 9, which will be described later, will be explained later.

As shown in FIG. 2, the leaf spring 9 has a ring shape as a whole, and a portion corresponding to each magnetic path extends to near the inner end of the inner leg piece 2a to form a spring portion 9a. At the tip (inward side) of the armature 10, there is a narrow part 9b which is approximately equal in width to the width of the armature 10 within a range shorter than the radial (longitudinal) length of the armature 10, which will be described later.
is formed. Other than this narrow part 9b, there is a wide part 9 having the same width as the auxiliary cork 5, that is, each yoke piece 6, 7.8.
It has become c.

The armature 10 has a rectangular parallelepiped shape that becomes slightly thinner toward the inside, and has a narrow portion 9b and a wide portion 9C as shown in FIG.
It is laser welded to the leaf spring 9 at the location where it spans. Further, a printing wire 12 is fixed to the inner end via an arm 11. The shape and size of this armature 10 are the same as those of the conventional example.

Next, the leaf spring 9 and the auxiliary yoke 5 are shown in FIGS. 3 and 4.
．． The relationship between amateur 10 and others will be explained in detail. The first yoke piece 6 has a cutout portion 6 at the center of its tip that is slightly wider than the armature 10.
a is formed. The second yoke piece 7 is formed with a similar cutout part 7a, and has a facing part 7b that faces the narrow part 9b of the leaf spring 9 and the side surface of the armature 10.
, 7b are arranged in series. Further, the third yoke piece 8 is provided with an auxiliary yoke piece 8a having a U-shaped planar shape at its tip. The distance between the opposing pieces of the auxiliary yoke piece 8a is the cutout part 6a.
, 7a, and the tip of the opposing piece is located slightly inward from the base end of the narrow portion 9b and faces three side surfaces of the narrow portion 9b of the leaf spring 9 with a slight gap therebetween. Further, the thickness of the auxiliary yoke piece 8a is set so that a slight gap is provided between the lower surface of the auxiliary yoke piece 8a and the upper surface of the facing portions 7b, 7b of the second yoke 7. Therefore, the cutout parts 5a, 7a and the auxiliary yoke piece 8a
The space formed between each piece becomes the armature accommodating part 5a, which is connected to the magnetic gap g2 interposed between the auxiliary yoke 5 and the end face of the inner leg piece 2a. Of course, in this case as well, the third yoke piece 8 and the auxiliary yoke piece 8a may be integrally molded using lost wax (precision casting) or the like, but in terms of manufacturing cost, it is more advantageous to manufacture them separately by press working. be. The armature 10 is disposed movably within the armature housing portion 5a, and magnetic flux is exchanged between the surface forming the armature housing portion 5a and the three side surfaces of the armature 10.

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.

When the coil 2 is energized, the magnetic flux of the coil 3 cancels out the magnetic flux of the permanent magnet 4, so that the armature 10 is released from attraction by the full spring force of the leaf spring 9, and the printing wire 12 protrude and print on the paper on the platen (not shown). In this operation, the second. 3rd yoke piece 7.8
requires a gap that does not interfere with the displacement operation of the leaf spring 9, and this gap is the predetermined gap g1.

In the dot printer head having such a configuration, even if the size of the armature 10 is the same as that of the conventional one, since the narrow portion 9b is formed at the tip of the leaf spring 9, the auxiliary yoke 5 is connected to the leaf spring 9.
The leaf spring 9 is divided into three yoke pieces above and below, and each yoke piece (in this embodiment, the auxiliary yoke pieces 8a of the second yoke 7 and the third yoke piece 8) has a narrow part 9a of the leaf spring 9. and facing portions (including the opposing pieces of the auxiliary yoke piece 8a in this embodiment) are arranged in series so as to sandwich the side surface of the armature 10. Therefore, the magnetic path area of the auxiliary yoke 5 can be increased,
Furthermore, the opposing area between the auxiliary yoke 5 and the armature 10 can be increased, thereby increasing the speed of operation of the dot printer head. Furthermore, when laser welding the armature 10 to the leaf spring 9, if the width of the welded part of the leaf spring 9 is narrow, the leaf spring will be hardened over the entire car, which may make it brittle and shorten its life. In the example, since the wide portion 9c is provided, elasticity can be ensured, and laser welding, which is advantageous in terms of cost, is possible.

[Effects of the Invention] In the dot printer head of the present invention, the leaf spring is formed into a ring shape as a whole, and the spring portion corresponding to each magnetic path extends inward, and the tip of the spring portion is shaped like a ring. Since a narrow portion approximately equal to the width of the armature is formed in a range shorter than the radial length of the armature, the auxiliary yoke can be connected to at least two yokes above and below the leaf spring without enlarging the armature. The area of the magnetic path is increased by dividing the yoke into two pieces, and in addition, each yoke piece has a narrow part of the leaf spring and a side face of the armature connected to each other so as to connect the auxiliary yoke and the armature. The opposing area can be increased, thereby increasing the speed of operation of the dot printer head.

IO-

[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. 3 is a perspective view of the main part, FIG. 4 is an exploded perspective view thereof, FIG. 5 is a sectional view of a conventional example, and FIG. 6 is a perspective view of the main part. 1.-1 magnetic path of the dot printer head, 2.. Yoke, 3.-. Coil, 4-. Permanent magnet, 5 (6,7°8
) - Auxiliary yoke, 5a - Armature housing section, 6.
...First yoke piece, 7-Second yoke piece, one facing part of 7a, 8...-Third yoke piece, 9-Leaf spring, 9a (9b, 9
c)---Spring part, 9b-narrow part, 9c-wide part,
10-armature, 12-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 the dot printer head in which a printing wire is fixed to the armature, the leaf spring has a ring shape as a whole, and a spring portion corresponding to each magnetic path extends inward, and the tip of the spring portion A dot printer head is provided with a narrow portion having a width substantially equal to the width of the aperture in a range shorter than the radial length of the aperture.