JPH0524215A - Wire dot printing head - Google Patents

Abstract

PURPOSE:To perform a stable printing operation by enabling magnetic interference which is to be generated between leakage magnetic flux from a coil and magnetic flux of a permanent magnet to be prevented even though the printing operation is performed at a high speed. CONSTITUTION:An armature 11 is arranged opposed to a core 2 on which a coil 3 is wound around. A printing wire 5 is fitted to one end side of the armature 11 via a lever 4. Magnetic flux of a permanent magnet around the core 2 is offset by making a current flow to the coil, and the armature 11 is driven to print with the printing wire 5. The armature 11 is molded by metal powder injection molding. Further, an absorbing surface 11A of the armature 11 is molded in the almost same form as an absorbing surface 2A of the core 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire dot print head capable of preventing magnetic interference generated between an armature and a core to improve suction force, an amateur member used in the wire dot print head, and the wire dot. The present invention relates to a printing device equipped with a print head.

[0002]

2. Description of the Related Art Generally, a wire dot printing head has a plurality of cores each having a coil wound around it and arranged in a circle, as described in, for example, Japanese Patent Application Laid-Open No. 2-41256. An armature having a print wire on one end side via a lever and a permanent magnet provided around the plurality of cores, and a current is applied to a coil wound around the cores. By canceling the magnetic flux of the permanent magnet, the armature is driven, and printing is performed by the print wire attached to the armature.

In the conventional wire dot print head, the suction surface of the armature and the suction surface of the core are formed in the shape shown in FIG. That is, the suction surface 1A of the armature 1 is formed in a rectangular shape, and the suction surface 2A of the core 2 is formed in an isosceles triangle. In the figure, reference numeral 4 is a lever provided on one end side of the amateur 1, and reference numeral 5 is a lever 4
The print wires attached to the tips of the respective are shown.

By the way, if the suction surface 1A of the amateur 1 and the suction surface 2A of the core 2 are shaped as shown in FIG.
When a current is passed through the coil 3 wound around the coil 3, a part of the magnetic flux 6 generated in the core 2 becomes a leakage magnetic flux to the permanent magnet as shown in FIG. 5, and magnetic interference with the magnetic flux caused by the permanent magnetic flux occurs. Is likely to occur.

Therefore, in the above-mentioned Japanese Patent Laid-Open No. 2-412256, slits are provided in the members (base, ring yoke, toothed yoke) that constitute the permanent magnet to reduce the cross-sectional area which is the path of the leakage magnetic flux. , Magnetic interference is prevented.

[0006]

However, in the above-mentioned conventional technique, even if the cross-sectional area which is the path of the leakage magnetic flux is made small, the shapes of the core and the armature are completely different, so that the leakage caused by the difference in cross-sectional area is caused. Insufficient to prevent magnetic flux. That is, in the wire dot print head, in order to speed up the printing operation, the state where the armature is attracted to the core by the magnetic flux of the permanent magnet (the coil is not excited),
A state in which the armature and the core are separated by applying a current to the coil and generating a magnetic flux in the direction opposite to the magnetic flux of the permanent magnet (the coil is excited)
And must be repeated at high speed. However, only by providing a slit in the member constituting the permanent magnet as in the above-mentioned conventional technique, in the process of switching the coil from non-excitation to excitation at a high speed, the leakage flux, which is a part of the magnetic flux by the coil, and the permanent magnet Magnetic interference occurs with the magnetic flux, and the force for attracting the armature to the core is weakened, so that it becomes difficult to secure the attraction force required for a stable printing operation.

An object of the present invention is to prevent a magnetic interference generated between a magnetic flux leaking from a coil and a magnetic flux of a permanent magnet even when a printing operation is performed at a high speed, thereby preventing a defective printing operation. Is to provide.

[0008]

In order to achieve the above object, the present invention provides a plurality of cores each of which is individually wound with a coil and arranged in a circle, and the cores are arranged so as to face the cores. An amateur having a print wire on one end side via a lever,
In a print head comprising a permanent magnet provided around the plurality of cores, a current is passed through the coil to cancel the magnetic flux of the permanent magnet, thereby driving an armature and performing printing with the print wire. The armature is formed by metal powder injection molding, and the suction surface of the armature has a shape substantially the same as the suction surface of the core.

Further, according to the present invention, a plurality of cores each having a suction surface formed in an isosceles triangle and each of which is wound with a coil and arranged in a circle, are arranged to face the cores, and An amateur having a print wire on the side through a lever,
In a print head comprising a permanent magnet provided around the plurality of cores, a current is passed through the coil to cancel the magnetic flux of the permanent magnet, thereby driving an armature and performing printing with the print wire. The amateur is formed by metal powder injection molding, and the suction surface of the armature is an isosceles triangle which is substantially the same as the suction surface of the core.

Further, according to the present invention, a plurality of cores each having a coil wound individually and arranged in a circle, and an armature arranged opposite to the cores and having a print wire on one end side via a lever are provided. And a permanent magnet provided around the plurality of cores, and a current is passed through the coil to cancel the magnetic flux of the permanent magnet, thereby driving an armature to perform printing with the print wire. At
The amateur is formed by metal powder injection molding, and the attraction surface of the amateur and the attraction surface of the core are shaped to prevent magnetic interference generated by the magnetic flux of the core and the magnetic flux of the permanent magnet.

It should be noted that the above-mentioned amateur uses Co of 48 to 5
It is composed of a permenda containing 3% and V of 0.5 to 3%.

Further, the present invention is a printing apparatus equipped with a print head which is improved.

The amateur member of the present invention is composed of a permendur containing Co of 48 to 53% and V of 0.5 to 3%, and the suction surface is an isosceles triangle and is formed by metal powder injection molding. It is a thing.

[0014]

According to the above construction, the attraction surface of the armature is made to have substantially the same shape as the attraction surface of the core, so that when the coil is excited, the magnetic flux generated from the core leaks to other than the attraction surface of the amateur. Therefore, the magnetic interference can be prevented because it does not flow back to the permanent magnet. As a result, the wire dot print head comes to perform stable printing.

By forming the armature by metal powder injection molding, it is possible to improve the processing accuracy of the armature, and since it is die molding, the yield is improved and the cost of the print head can be reduced.

Furthermore, since the permender having strong magnetism is used as the amateur material, a stable attractive force can be obtained without weakening the magnetic flux.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as those in the prior art are designated by the same reference numerals.

FIG. 2 shows a schematic structure of the wire dot print head of the present invention. In the figure, the print wire 3 is attached to one end of the amateur 11 via a lever 4,
A leaf spring 7 is provided on the other end side of the armature 11. Further, the core 2 is arranged so as to face the amateur 11,
A coil 3 is wound around the core 2. In order to prevent direct contact between the amateur 11 and the core 2,
A resume sheet 8 is provided between the amateur 11 and the core 2.

Although one each of the armature 11 and the core 2 is shown in the drawing, in reality, a plurality of them are provided around the center line 0-0 and arranged in a circle.
An annular permanent magnet 9 is arranged outside the core 2. The permanent magnet 9 is joined to the core 2 through the lower portion of the core 2 which is bent in a substantially U shape.

In the wire dot print head having the above structure,
When no current flows in the coil 3 wound around the core 2, the magnetic flux 10 by the permanent magnet 9 flows in the magnetic flux path, and the armature 1 is attracted to the core 2 against the biasing force of the leaf spring 7. . When a current is passed through the coil 3, the magnetic flux 6 generated by the coil 3 is generated in the direction opposite to the magnetic flux 10 generated by the permanent magnet 9, and the magnetic flux 10 is canceled and reduced or reduced.
The armature 1 is released, and the armature 1 is driven by the biasing force of the leaf spring 7 to perform the printing operation.

Further, the suction surface of the amateur 11 is formed in a shape as shown in FIG. That is, amateur 1
The suction surface 11A of No. 1 is formed in an isosceles triangle like the suction surface 2A of the core 2. The suction surface 11A of the amateur 11 and the suction surface 2A of the core 2 are arranged so as to face each other.

The amateur 11 uses cobalt (Co) of 48-
53% and vanadium (V) 0.5 to 3% permenda, and metal powder injection molding (MIM: Metal I).
njection Molding).

A method of manufacturing the amateur 11 is shown in FIG. First, a binder that is a binder is added to the fine metal powder 21 having an average particle size of 5 to 10 μm, and the fine metal powder and the binder are mixed and combined (step 22). Furthermore, after kneading (step 23), extrusion molding is performed into a mold by an injection molding machine (step 24). Then, the extruded body is heated to remove the binder from the extruded body (step 25), and then sintered and sintered by a method similar to the powder metallurgy method (step 26) to obtain a product 27.

When the amateur 11 is manufactured in this manner, the amateur 11 having an excellent electromagnetic function and a good thermal function can be obtained. That is, since the electromagnetic material manufactured from the fine metal powder has a high sintering density, a high magnetic flux density can be realized. Further, the electromagnetic material produced from the fine metal powder does not lose its mechanical properties even if it is sintered at a high temperature, and has excellent thermal properties.

Here, as an amateur material, vanadium (V) is 2%, cobalt (Co) is 49%, and iron (F) is used.
e) is a permendur (2V-49Co) consisting of 49%, and silicon (Si), which has been used conventionally, is 3%,
3% silicon steel consisting of 97% iron (Fe) (Fe-3S
Let's compare with the characteristics of i).

First, the magnetic properties of permendur and 3% silicon steel are shown in Table 1.

[0027]

[Table 1]

From Table 1, it is understood that when Co is mixed, the magnetic properties of the permendur are improved as compared with the 3% silicon steel. When V is 3% or more, the magnetic characteristics deteriorate.

Next, Table 2 shows the mechanical properties of permendur and 3% silicon steel.

[0030]

[Table 2]

From Table 2, it is understood that when Si and V are mixed, the mechanical properties of the permendur are better than those of the 3% silicon steel. In addition, when V is mixed, a high temperature (for example,
Even if the V content is 2% and the sintering temperature is 800 to 900 ° C.), the mechanical properties are not impaired.

According to this embodiment, since the amateur 11 is molded by metal powder injection molding, the suction surface 11A of the armature 11 is formed into an isosceles triangle having substantially the same shape as the suction surface 2A of the core 2. It can be approximated easily. as a result,
Magnetic flux leakage is eliminated and magnetic interference does not occur, and stable printing operation can be performed. Moreover, since the material of the amateur 11 is permend, an amateur member having strong magnetism can be obtained.

Further, in the metal powder injection molding, since a metal part having a complicated shape can be molded with high precision without requiring machining, it is possible to easily reduce the number of parts and the number of steps.

In the above embodiment, the shapes of the suction surface 11A of the amateur 11 and the suction surface 2A of the core 2 are isosceles triangles, but the invention is not limited to this. The two suction surfaces 2A can have any shape as long as they have substantially the same shape.

[0035]

As described above, according to the present invention,
By making the suction surface of the core and the amateur almost the same shape,
It is possible to eliminate magnetic flux leakage, prevent magnetic interference, and perform stable printing operation.

Further, since the armature is formed by metal powder injection molding, metalworking and the like can be omitted and the working accuracy can be improved, and the yield can be improved and the cost of the print head can be reduced. it can.

[Brief description of drawings]

FIG. 1 is a perspective view of an armature and a core according to the present invention.

FIG. 2 is a schematic configuration diagram of a wire dot print head according to the present invention.

FIG. 3 is a flow chart showing a procedure for manufacturing an amateur member by metal powder injection molding.

FIG. 4 is a perspective view of an amateur and a core in the related art.

FIG. 5 is an explanatory diagram of leakage magnetic flux.

[Explanation of symbols]

2 cores 3 coils 4 levers 5 printing wire Magnetic flux from 6 coils 7 leaf spring 8 Resilient sheet 9 Permanent magnet 10 Magnetic flux from permanent magnet 11 amateurs

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tadashi Hayakawa             4-3 Kanda Surugadai, Chiyoda-ku, Tokyo             Within Hitachi Techno Engineering Co., Ltd. (72) Inventor Koji Sato             4-3 Kanda Surugadai, Chiyoda-ku, Tokyo             Within Hitachi Techno Engineering Co., Ltd. (72) Inventor Masahiro Inui             4-3 Kanda Surugadai, Chiyoda-ku, Tokyo             Within Hitachi Techno Engineering Co., Ltd. (72) Inventor Katsuji Fukasaku             Hitachi, Ltd. 1070 Ige, Katsuta City, Ibaraki Prefecture             Factory Mito Factory (72) Inventor Ryo Asano             Hitachi, Ltd. 1070 Ige, Katsuta City, Ibaraki Prefecture             Factory Mito Factory (72) Inventor Masaaki Ariga             Hitachi, Ltd. 1070 Ige, Katsuta City, Ibaraki Prefecture             Factory Mito Factory (72) Inventor Katsumi Aoki             Hitachi, Ltd. 1070 Ige, Katsuta City, Ibaraki Prefecture             Factory Mito Factory

Claims (6)

[Claims] 1. A plurality of cores in which coils are individually wound and arranged in a circle, and an armature arranged opposite to the cores and having a print wire on one end side via a lever,
In a print head comprising a permanent magnet provided around the plurality of cores, a current is passed through the coil to cancel the magnetic flux of the permanent magnet, thereby driving an armature and performing printing with the print wire. A wire dot print head characterized in that the armature is formed by metal powder injection molding, and the suction surface of the armature has substantially the same shape as the suction surface of the core. 2. A plurality of cores each having a suction surface formed into an isosceles triangle and each of which is individually wound with a coil and arranged in a circle, and a plurality of cores which are arranged so as to face the cores, and a lever is provided on one end side An armature having a print wire and a permanent magnet provided around the plurality of cores, and a current is passed through the coil to cancel the magnetic flux of the permanent magnet, thereby driving the armature to perform the printing. In a print head that prints with a wire, the armature is formed by metal powder injection molding, and the suction surface of the armature is an isosceles triangle that is substantially the same as the suction surface of the core. . 3. A plurality of cores, each of which is individually wound with a coil and arranged in a circle, and an armature, which is arranged so as to face the cores and has a print wire on one end side via a lever,
In a print head comprising a permanent magnet provided around the plurality of cores, a current is passed through the coil to cancel the magnetic flux of the permanent magnet, thereby driving an armature and performing printing with the print wire. The amateur is formed by metal powder injection molding, and the attraction surface of the amateur and the attraction surface of the core are shaped to prevent magnetic interference generated by the magnetic flux of the core and the magnetic flux of the permanent magnet. Wire dot printing head. 4. The print head according to any one of claims 1 to 3, wherein the armature is made of Co of 48 to 53.
%, V is 0.5 to 3%, and the wire dot print head is characterized by comprising. 5. A printing apparatus equipped with the print head according to claim 1. 6. Co of 48 to 53% and V of 0.5 to 3%
An amateur member made of metal powder injection molding, which is composed of a permendur including the suction surface and has an isosceles triangle shape.