JPH0621720Y2 - Wire print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a wire print head in a wire dot printer.

<Prior Art> As a wire print head used for a conventional dot printer, there is one having a structure shown in FIG. This wire print head is of a so-called spring charge type, and a base 3, a permanent magnet 4, a base plate 5, a spacer 6, a leaf spring 7, and a yoke 8 are sequentially laminated via a clamp 9 between a guide frame 1 and a cap 2. Has been done.

An armature 10 is attached to the flexible portion of the leaf spring 7, and the base of the printing wire 11 is fixed to the tip of the armature 10. The tip 11a of the printing wire 11 is formed so as to be guided and projected to the platen side by the guide 1a formed on the guide frame 1.

An electromagnet m is provided substantially in the center of the base 3. The electromagnet m is formed by mounting a coil bobbin 14 around which a coil 13 is wound on a core 12.

On the other hand, on the lower surface of the base 3, there is provided a circuit board 15 which is connected to a lead wire from the coil 13 to conduct electricity.

In the wire print head having the above-mentioned structure, a so-called magnetic closed circuit is formed in which the magnetic flux of the permanent magnet 4 returns to the permanent magnet 4 again through the base plate 5, the spacer 6, the yoke 8, the armature 10, the core 12 and the base 3. To be done. The armature 10 is attracted to the core 12 by this magnetic closed circuit and the leaf spring 7 is bent, so that strain energy is accumulated. That is, the leaf spring 7 is in a biased state.

When the coil 13 is excited in such a state and a magnetic flux is generated by the electromagnet m in the direction opposite to the magnetic flux of the magnetic closed circuit, the attraction force of the armature 10 by the core 12 is reduced, and the leaf spring 7 in the flexed state is accumulated. It is released from the suction state by the bending energy and returns to the original state. This makes the armature
A wire 11 attached to the tip of 10 projects from the guide 1a, and the tip 11a presses an unillustrated ink ribbon and a print medium against the platen, and prints a desired character or graphic pattern.

In the wire print head described above, downsizing and high printing speed have been especially demanded in recent years, and therefore, in order to efficiently use the magnetic force of the permanent magnet 4, the magnetic efficiency is optimized. Specifically, the core 12 is changed into a shape with the highest magnetic efficiency. A current I is applied to a one-turn circular coil having a normal radius r (m).
When (A) is passed, the central magnetic field H (A / m) of the coil is H
= I / 2r. As a result, if the current I is constant, the smaller the radius r is, the larger the magnetic field H is. Therefore, one end surface 12a on the side where the armature 10 is sucked is replaced with the other end surface 1 on the base side.
Form narrower than 2b. Armature by this core 12
The magnetic flux density at the attraction points of 10, that is, at the one end surface 12a increases, and the attraction of the leaf spring 7 increases. As a result, the leaf spring 7 having a large spring constant can be attracted, and conversely, when the leaf spring 7 is released from bending, it can be returned at a high speed. Moreover, since the permanent magnet 4 can be downsized, the wire print head can be downsized accordingly.

However, in the above electromagnet m, the coil bobbin 14 mounted on the core 12 has a hollow portion formed into a tubular shape having a size substantially equal to the maximum diameter of the core 12, so that the center axis of the core 12 and the coil bobbin 14 are formed. The center lines of the hollow portions do not coincide with each other, and a gap h is generated on the one end face 12a side.

That is, in the core 12 formed by narrowing from the other end surface 12b to the one end surface 12a, the central magnetic field of the coil 13 decreases as going from the other end surface 12b to the one end surface 12a. In other words, the total amount of magnetic flux exerted on the core 12 is reduced.

Therefore, the inventor et al.
As shown in the figure, we proposed a wire printing head in which a hollow part of a coil bobbin is formed in conformity with the shape of the core, and the hollow part of the coil bobbin around which the coil is wound is attached in close contact with the outer peripheral surface of the core. Sho-139322).

<Problems to be Solved by the Invention> However, in the wire print head having the above configuration,
Since the hollow portion of the coil bobbin 14 is formed in conformity with the outer shape of the core 12, as shown in FIG.
Coil bobbin 14 upper flange 14a and lower flange 1
The winding margin 14f formed by 4b and the body portion 14c includes one end surface 12a of the core 12.
Thus, a taper angle θ corresponding to the taper formed by the other end surface 12b is formed. On the other hand, the coil 1 wound around the winding allowance 14f
3, the winding start end 13a and the winding end 13b are respectively the connection terminals 1
Since it is connected to 6a, 16b and is connected to the printed circuit board 15 arranged on the lower surface of the base 3, the winding start end 13a is arranged on the lower flange 14b, and the winding start end 13a is sequentially wound on the upper flange 14a side. become.

However, as shown in FIG. 7 which is an enlarged view of the Y part of FIG.
Since the taper angle θ is attached to the upper surface of 14f, a component force of ΔT = Tsinθ acts when the coil tension T starts winding. Moreover, since there is no stopper or the like against the component force ΔT in the first turn 13-1 on the winding start side, a deviation occurs, and it is difficult to sequentially wind the second and third turns.
That is, the aligned winding work of the first layer becomes extremely difficult, and the coil 13 cannot be formed into multiple layers and aligned winding within the winding margin 14f of the coil bobbin 14. Therefore, it becomes difficult to wind the coil with the maximum number of turns, and ultimately the core of the electromagnet cannot be efficiently magnetized.

<Means for Solving the Problems> In order to solve the above problems, the present invention is characterized in that a winding start end of a coil wound around a coil bobbin is disposed on a flange of a coil bobbin located on one end face side of a core. It is a thing.

<Operation> That is, if the winding start end of the coil is arranged on the flange located on the one end face side of the core and the coil is wound, the above flange acts as a so-called stopper even if a component force is exerted due to the taper angle formed by the coil bobbin. It can be placed in the first turn without shifting. As a result, the 1st layer is formed by sequentially winding the 2nd and subsequent turns, and the 1st turn of the 2nd layer also falls between the 1st and 2nd turns of the 1st layer, and it shifts even if a component force is applied as above. Instead, it is possible to wind in sequence.

<Example> A wire print head according to the present invention will be described in detail with reference to the drawings.

The same components as those of the wire print head described in the conventional example will be described with the same reference numerals, and the description thereof will be omitted unless the configuration and its driving are particularly different from those of the conventional example.

FIG. 1 is a schematic sectional view showing the structure of a wire print head according to the present invention.

That is, the guide frame 1, cap 2, base 3, permanent magnet 4, base plate 5, spacer 6, leaf spring 7, yoke 8
Are stacked via the clamp 9 in the same manner as in the conventional example. The armature 10 and the printing wire 11 are also attached and fixed in the same manner as described in the conventional example, and the tip 11a of the printing wire 11 is projected from the guide 1a.

The electromagnet M that attracts and releases the armature 10 is a coil 13
A coil bobbin 14 wound around is attached to a core 12, and this core 12 is formed by sandwiching one end face 12a on the suction side from the other end face 12b on the base side, forming a so-called substantially truncated cone shape. .

On the other hand, the coil bobbin 14 mounted on the core 12 having the above-mentioned configuration,
A body portion 14c is formed between an upper flange 14a and a lower flange 14b, and a hollow portion 14d is provided between both flanges 14a and 14b. The inner wall 14e of the hollow portion 14d has a substantially frusto-conical core.
The core 12 is formed in substantially the same shape as the core 12 in close contact with the outer peripheral surface 12c. Therefore, a taper angle similar to that of the outer peripheral surface 12c of the core 12 is attached to the surface of the winding margin 14f formed between the upper flange 14a and the lower flange 14b and on the outer surface side of the body portion 14c.

Next, the work of winding the coil 13 around the coil bobbin 14 will be described.

As shown in FIG. 2, the winding start end 13a of the coil 13 is located on the one end face 12a side of the core, that is, the upper flange 1
It is arranged at 4a, and starting from this, it is sequentially wound in the winding margin 14f toward the lower flange 14b side. At this time, the coil tension T is applied. Then, the first turn 13-1 is △ T = Tsin
The component of θ works. However, since the upper flange 14a plays the role of a stopper, the first turn 13-1 is fixed without being displaced.

Next, wind the second turn 13-2. This second turn 13
In -2, the first turn 13-1 works as a stopper. Therefore, the first layer can be aligned and wound by sequentially winding the third turn 13-3 and the fourth turn.

Next, the 1st turn of the 2nd layer enters between the 1st turn 13-1 and the 2nd turn 13-2 of the 1st layer and is fixed without slipping,
Similarly, each turn is wound and the second layer is aligned and wound.
In this way, the winding can be performed in a line in multiple layers, and the desired coil 13 can be obtained. Then, the coil winding start end 13a is connected to the connection terminal 16a molded in the coil bobbin 14, and the coil winding end 13b is connected to the connection terminal 16b. Since the winding start end 13a of the coil is disposed on the upper flange 14a as described above, and the printed circuit board 15 connected to the connection terminal 16a is disposed on the lower surface side of the base 3, the connection terminal 16a is used in the case of so-called odd winding. It is sufficient to mold the inside of the body portion 14c and connect the both. In the case of an even number of windings, the winding end 13b is also arranged on the upper flange 14a, and the connection terminal 16b is also similarly formed.
Both can be connected to each other on the upper flange 14a side by molding in 14c. Further, as shown in FIG. 3 (a), the coil winding work is performed in a state where the winding start end 13a provided on the upper flange 14a and the connection terminal 16a are connected, and after the work is completed,
As shown in the figure (b), connect the terminal 16a to the lower flange 14b.
It may be bent to the side (arrow direction) and hung in the direction of the print base plate. Also in this case, the connection terminal 16
Similar to the above, b is provided on the upper flange 14a, and after the winding work is finished, the winding end 13b is connected and bent in the same manner. In the above coil winding work, the coil bobbin 14 is not mounted on the core 12 in advance, the hollow portion 14d is fitted to the winding rotating body (not shown), and the coil bobbin 14 is rotated in a predetermined direction to conduct electricity. The coil 13 is formed by winding a wire.

In the above-mentioned embodiment, the so-called spring charge type wire print head has been described, but the present invention is not limited to this, and a so-called clapper type wire print head or the like which prints when a coil is energized to draw a leaf spring is used. Needless to say, it is also applicable.

<Effects of the Invention> As described above, in the wire print head of the present invention, the winding start end is arranged on the flange located on the one end face side of the core in the winding margin of the coil bobbin and the winding is performed. It can be placed at the turn without any deviation. Therefore, it is possible to form the coil of the multilayer winding by sequentially winding starting from the first turn, and it is possible to wind the maximum number of turns within the limited winding margin.

As a result, the magnetic flux generated by the coil is increased, and the drive efficiency of the wire print head can be significantly improved. Moreover, the winding operation is facilitated and the conductive wire material forming the coil can be reduced. Further, by reducing the power supply capacity, it is possible to downsize the dot printing printer and reduce its cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a dot print head of the present invention, FIG. 2 is a schematic cross-sectional view illustrating a winding state of a coil, and FIGS. 3 (a) and 3 (b) are other embodiments. FIG. 4 is a schematic sectional view showing a conventional dot print head, FIG. 5 is a schematic sectional view of a conventional dot bobbin improved coil bobbin, and FIG. 6 is an enlarged view of an X portion in FIG. FIG. 7 and FIG. 7 are enlarged views of the Y portion in FIG. 12 ... Core, 12a ... One end surface of the core on the suction side, 12b ... The other end surface of the core on the base side, 13a ... Winding end of coil, 13b ... Winding end of coil, 14 ... Coil bobbin, 14a ... Upper flange, 14b ... Lower flange, 14c ... Body, 16a, 16b ... Connecting terminals.

Claims (1)

[Scope of utility model registration request] 1. A print in which an armature is attracted to a core of an electromagnet by a magnetic flux of a permanent magnet to bend a leaf spring, and the magnetic flux of the permanent magnet is canceled by urging the electromagnet to fix the armature to the tip of the armature. In a wire print head for driving a wire, the electromagnet is one in which one end surface of a core is formed narrower than the other end surface and a hollow portion of a coil bobbin around which a coil is wound is mounted on the core, and the electromagnet is wound around the coil bobbin. A wire print head in which a winding start end of the coil is disposed on a flange located on the one end face side of the core.