JPS6285958A - Wire dot head - Google Patents

Abstract

PURPOSE:To increase collision velocity against the recording paper side of wire through the actuation of an excitation coil to attract an armature to a recording direction with the super magnetic force of the coil and enable fast recording to be performed by arranging permanent magnets across an armature in an opposite position to an excitation coil. CONSTITUTION:The base end of a wire 15 is fixed to the tip of an armature 16. A leaf spring 17 is fastened to the base end of the armature 16. A core 18 is arranged in an opposite position to the wire 15 of the armature 16 and permanent magnets are overlapped on the one end of the core 18. Further, a yoke 20 is arranged on the overlapped magnet and one end of the leaf spring 17 is fixed to the yoke. On the upper end of the yoke 20, one end of a down- facing 'U' shaped core 21 is fastened, whilst the other end of the yoke 21 is opposed to the core 18 across the armature 16. An excitation coil 22 is fitted to the other end of the coil. Thus a permanent magnet 19 and the coil 22 are arranged on a mutually opposite position across the armature 16. Accordingly, the coil 22 and the permanent magnet 19 become powerful and a high- performance wire dot head capable of fast recording is obtained.

Description

Detailed Description of the Invention 3. Brief Description of the Invention and Field of Industrial Application 1 The present invention relates to a wire recording head, in particular a high-speed,
This relates to a low power driven wire recording spatula.

[Prior Art] A conventional wire recording head of this type is constructed as shown in FIG.

5-) The one indicated by 2 is a permanent magnet formed into an erotic and plate-like shape and magnetized in the axial direction. It is set up on a cliff. An annularly formed middle yoke 3 having the same diameter as the permanent magnet 21- is sunk therein, and an annular 1- A yoke 6 is provided, further comprising: 1. York 61. A tip kite 7 is provided with a guide portion 7a having a central portion Φ.

The tip kite 7 kites a plurality of wires 8 for striking, each wire 8 is inserted through the kite part 7a, and the tip of each wire 8 is connected to an open lower b formed at the tip of the kite part 7a. The rear end has the same number of leaf springs 5 as the wires 8.
A wire 8 is cantilevered and fixed to each tip of an armature 9.

On the other hand, the reference numeral 10 designates the core of an electromagnet for driving the armature 9, which is formed in a cylindrical shape and is wound with a coil 11, and is provided in the same number as the leaf springs 5, that is, the same number as the armature 9 and the wires 8. Then, as shown in FIG. 7, permanent magnets 2
They are arranged on the lower yoke 1 in a circle at equal intervals inside the lower yoke 1.

A magnetic path is constituted by the permanent magnet 2, the middle yoke 3, the leaf spring 5, the yoke 6, the armature 9, the core 10, and the lower yoke 1, each of which is made of a magnetic material.

In the configuration shown above, the current to the coil 11 is cut off during non-recording, and each platenone 5 is attracted to each core 10 magnetized by the permanent magnet 2 together with the armature 9 and is bent. , the tip of each wire 8 is located at the same position as the tip of the guide portion 7a of the tip kite 7.

In this case, in the magnetic path marked -1-, the magnetic flux 12 generated by the permanent magnet 2 appears along the path and direction shown by the solid line and single arrow in FIG.

On the other hand, during recording, when the selected coil 11 is energized and excited, a magnetic flux 13 is generated which appears along the path and direction shown by the dotted line and arrow in FIG. lose attraction.

As a result, the armature 9 is displaced together with the plate spring 5 in the opposite direction in the figure due to the elastic force of the plate spring 5, and the wire 8 is displaced in the same direction. Similarly, a recording medium (not shown) is struck through the drum and recorded.

[Problems to be Solved by the Invention] However, in the structure as described above, magnetic flux is also generated in the core lO' of the coil 11' adjacent to the energized coil 11, as shown in FIG. Core 1 as shown at 14
A magnetic flux appears that goes around from zero through the adjacent core 10'. and.

At this time, the loop of magnetic flux 13 includes a permanent magnet 2 whose magnetic permeability is approximately equal to that of air, while the loop of magnetic flux 14 includes only adjacent armatures 9 and 9' connected by air. The other parts constitute a closed loop. Therefore, the magnetic resistance of the loop of magnetic flux 13 is not sufficiently smaller than the magnetic resistance of the loop of magnetic flux 14. As a result, the magnetic flux 14 becomes relatively large, causing so-called magnetic interference. The magnetic flux 14 is equal to the direction of the magnetic flux generated by the permanent magnets in the core 10'. Therefore, in order to open the armature 9', it is necessary to apply approximately 20% more current to the coil 11' than when the armature is opened alone. However, since the 1L flow is not actually increased, there is a problem in that the density of don't prints varies due to fluctuations in wire operating time and printing force, resulting in a decrease in print quality.

Furthermore, the head itself becomes hot due to the heat generated from the head, increasing the resistance value of the coil and decreasing the semi-magnetic value, reducing the strength of the generated magnetic field and making it impossible to print. Put it away. Therefore.

To avoid this, a temperature sensor is used to detect when the head temperature exceeds a certain value and stop printing for a few seconds1.
:I was letting it happen. For this reason, the head itself must be driven at high speed.
Even though it was me, there was a problem that I couldn't record at high speed due to this loss of stop time.

Furthermore, in order to perform high-speed recording, it is necessary to move the wire 8 at high speed and to increase the collision speed with the recording paper through the ink ribbon. To achieve this, the Yagi force of the leaf spring 5 can be strengthened, but as the force increases, the attractive force of the permanent magnet 2 must also be strengthened, and the demagnetizing coil 11 also becomes larger, making the entire head larger. Then, there is a problem that it becomes a large Φ:111.

[Means for solving the problems] In the present invention, in order to solve the problems mentioned above,
A structure was adopted in which the excitation C6 coil was placed on the recording direction side of the wire with respect to the armature, and the permanent magnet was placed on the opposite side of the armature from the excitation coil.

[Function] When the above-described structure is adopted, the magnetomotive force of the excitation coil acts to attract the armature in the recording direction, and the collision speed of the wire against the recording paper side can be increased.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

[First Embodiment] FIGS. 1 to 3(A) and FIGS. 4 and 5 explain the first embodiment of the present invention. In the figures, the reference numeral 15 is a wire, Its base end is fixed to the tip of the armature 16. A leaf spring 17 is fixed to the base end of the armature 16. What is indicated by the reference numeral 18 is a core, which is arranged on the opposite side of the armature 16 from the wire 15. A permanent magnet 19 is placed on the 1- side of one end of the core, and a yoke 20 is further arranged on the 1- side of the core. One end of the handle 1 is fixed to this yoke.

Ru.

Further, one end of a downwardly facing "U"-shaped core 21 is fixed to the 1- side of the yoke 17, and the other end of this yoke 21 faces the core 18 with the armature 16 in between, and this part is energized. A coil 22 for use is attached.

-(-The above-mentioned members form a drive unit for one wire, and these are arranged radially in a plurality of sets corresponding to the number of wires.

On the other hand, FIG. 3(A) shows a magnetic circuit.

In the figure, the symbol Um is the magnetomotive force of the permanent magnet 19, UC is the magnetomotive force of the coil 22, and Rgl is the armature 16 and core 1.
8 and includes the L magnetic resistance of the permanent magnet 19.

Furthermore, Rg2 is the magnetic resistance between the gap between the armature 16 and the core 2, RY is the magnetic resistance between the gap between the armature 16 and the yoke 20, and Φl is the loop Um-Ry-R.
The magnetic flux of g l-Um, Φ2 is the loop Uc-Rg2-Uy
With a magnetic flux of -Uc, this direction is assumed to be positive.

At this time, the following magnetic flux equation holds true for Φ1 and Φ2.

On the other hand, Fig. 4 shows the force relationship, and in the figure fl
is the force acting on the cap between the armature 16 and the core 18. f2 is the force that moves the gap between the armature 16 and the core 18.

Note that, if the eccentric force of the leaf spring 17 is fs, then fl>f2+f3 (2) when no current is flowing through the coil 22.
Therefore, the armature 16 is attracted to the core 18 when not driven.

Next, the operation of this embodiment will be explained. When not driven, fl>f2+fS, so the magnetic flux Φl.

Φ2 is expressed by the formula F.

On the other hand, when current is applied to the coil 22 to excite it and Uc is gradually increased, Φ1°Φ2 changes as shown in FIG.

Since the rate of increase in Φ2 is large, the relationship fl<f2+fs=・(5) is immediately established)'/: The armature 16 described in II moves in the direction of the core 21, that is, opens the printing operation. Therefore, the relationship between Rgl and Rg2 in Iiii+ is Rgl-(
Magnetic resistance of permanent magnet) ≦ Rg2...(7) Since it is 1 indeterminate, 1 The armature 16 is the core 18
is adsorbed to.

In this way, during recording, the action of attracting the armature 16 by the magnetomotive force of the centering coil 22 (movement) can accelerate the collision speed of the wire, making high-speed recording possible.

Furthermore, when the two-leg structure is adopted, the permanent magnet 19 and the coil 22 are arranged on opposite sides of the armature 16, so that there is room for the permanent magnet 19 on the inside and the coil 22 on the outside.

Therefore, compared to a wire dot head with the same external shape, the coil 22 and permanent magnet 19 can be made stronger, the spring constant (spring force) of the leaf spring 17 can be increased, and the leaf spring 17 can be made stronger. 17's liberating power can be fully extracted.

As a result, the collision speed with respect to the recording paper side increases, and a high-performance wire dot head that records at high speed can be obtained.

Moreover, a wire dot head with high performance can be made more compact.

Furthermore, since there are loops without permanent LB stones in the magnetic circuit seen from the coil, leakage of magnetic flux is reduced, and even in operation that drives many wires (multi-pin), ■ per pin (one wire) can be driven with the same power as when operating with 1 pin. This allows wire ends to be created that generate less heat.

[Second Example] The third IΔ(B) describes the second example of the present invention, and in this example, the direction of the magnetomotive force Uc is the same as that of the first example. This is different from Figure (A).

Therefore, the magnetic flux Φl, Φ
If the direction of 2 is determined and this is positive, it is expressed as.

In addition, the force f acting between the armature 16 and the camp is 1 mJJ'i ligature S on the opposing surface of the armature and the camp.
, the magnetic permeability of air is used, and the magnetic flux is Φ, then the following 9th
Expressed by the formula.

2 tiles S At this time, the relationship between the forces fL and f2 acting between the armature 16, the core 18, and the core 21 and the force fs of the leaf spring is the same as that shown in FIG. 4.

-, lj, when the deflection of the plate/henne 17 is O, the armature 16 is attracted to the core 18.

At this time, the magnetic resistance Rgl of the two core caps.

The relationship between Rg2 and Rg2 is Rgl<Rg2, and the force relationship is fl
>f2+fs.

That is, Uc=0, that is, a standby state in which the coil 22 is not excited! At exit, the armature 16 is attracted to the core 18.

In this state, in order to excite the coil 22 and move the armature 16 in the direction of the core 21, fl<f2+fs
holds, and 1γ is required. Also.

Armature 16. due to the energy of the magnetic field. ! : The force that moves D a 18.21 by 1 is proportional to the square of the central flux Φ, as shown in equation (8).

Here, assuming that the opposing areas S of the armature 16 and the core 18.21 are the same, and comparing the magnitudes of the magnetic field forces f1 and f2, the following equation (10) holds true.

2-fl Therefore, armature 16 when C paneca fs is not considered.
starts moving toward the core 21 when the numerator of formula (10) is -20, that is, (RglUc + Rg2Um) = O
Or ((Rgl+2RY)U c −(Rg 2
+ 2 Ry) When Um=0.

That is, U c = -Rg 2 U m / Rg 1
, or Uc= (Rg2+2Ry)Um/ (Rg
l+2RY).

・Considering the force and magnetic resistance (Rm) of the permanent magnet itself, Rg
Since there is a condition that 2<Rg 1 +Rm, comparing the absolute values of both names, Uc= (Rg2+2Ry)Um/
(Rgl+2Ry) (7) is smaller.

That is, when the direction of the magnetomotive force Uc of the coil 22 is negative, it is possible to move the armature 16 toward the core 21 with a smaller magnetomotive force.

For the reasons mentioned above, the arrangement of the coils and permanent magnets in this embodiment is the same as in the first embodiment, but as shown in Fig. 3(B).
As shown in , the direction of the magnetomotive force Uc is reversed.

However, the direction indicated by the arrow of magnetic flux Φ2 in Fig. 3(B) is the direction assumed to derive equation (1) by applying Kirchhoff's law to the magnetic circuit, and in reality the magnetomotive force Uc of the coil is The direction is opposite depending on the polarity of.

This state is shown by the dotted arrow in FIG. 1(B).

As shown in Figure 1 CB), the magnetic flux caused by the coil and the magnetic flux caused by the permanent magnet overlap from the yoke 20 to the armature 16, so they strengthen each other, and the armature 16 is moved with a smaller magnetomotive force. Can be driven.

In addition, since the magnetic flux Φ2 passes through the armature 16 and enters the core 21 side through a slight gap, this magnetic flux becomes an attractive force on the magnetic pole surface of the core 21 that faces the armature 16, driving the armature 16 at a higher speed. can do.

In this way, the coil 22 is energized for a predetermined time, and after being excited, when the current to the coil 22 is cut off, the armature 16 becomes fl>f2+fs due to the energy of the magnetic field of the permanent magnet 19, is attracted to the core 8, and is again There will be a waiting list of 1 month.

In addition, by adopting the structure described above, it becomes possible to combine the features of a conventional spring-charged head and a Kuchuppa-type hend with almost no increase in the number of parts, and it is possible to eliminate malfunctions caused by armature rebound. Stability is eliminated and the wire can be driven at high speed.

[Effects of the Invention] As is clear from the above description, according to the present invention, the excitation coil and the permanent magnet are placed on opposite sides of the armature, and the coil is placed on the side in the recording direction by the wire. Therefore, the magnetomotive force of the coil is used to attract the armature, making it possible to start a wire dot head that is small and capable of high-speed recording.

[Brief explanation of drawings]

Figure 1 (A), Figure 2, Figure 3 (A), Figure 4, and Figure 5.
The figures are for explaining the first embodiment of the present invention.
A) is a side view of the wire drive unit, FIG. 2 is a perspective view of the wire drive unit, FIG. 3A is a magnetic circuit diagram, and FIG.
The figure is an explanatory diagram of the force relationship, Figure 5 is a diagram showing the relationship between the riveting force and magnetic flux, and Figures 1 (B) and 3 (B) are the second diagram of the present invention.
A side view of a wire drive unit and a magnetic circuit 1Δ to explain an embodiment of the invention, FIGS. 6 to 9 illustrate a conventional structure, FIG. 6 is a sectional view of a wire dot head, and FIG. 7 shows a core arrangement. FIG. 8 is an explanatory diagram of the magnetic path, and FIG. 9 is an explanatory diagram of the conventional drawbacks. 15... Wire 16... Armature 17
...Plate spring 18.21...Core 19...
Permanent magnet 20...Yoke 22...Excitation coil patent ratio V person Canon Co., Ltd. representative Patent attorney Takashi Kato; :゛・-1-
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Claims (1)

[Claims] 1) An armature having a fixed base end of a wire and supported by a leaf spring, a set of cores arranged in the axial direction of the wire with the armature in between, and an excitation coil. The wire dot head is characterized in that an excitation coil is provided on the core located in the recording direction of the wire, and a permanent magnet for attracting the armature is provided on the core side located on the opposite side of the coil, sandwiching the armature. Wire dot head. 2) The wire dot head according to claim 1, wherein a magnetomotive force is generated in the excitation coil so that a magnetic flux is generated in a direction that cancels the magnetic flux of the permanent magnet. 3) The wire dot head according to claim 1, wherein the excitation coil generates a magnetomotive force so that magnetic flux is generated in a direction that strengthens the magnetic flux generated by the permanent magnet.