JPH0214419Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a wire dot printer, and particularly to its print head structure.

[Background of the idea]

First, FIG. 1 shows a partially cutaway sectional view of a print head according to a conventional example.

In the figure, 1 is a wire provided on the free end side of the leaf spring 2, one end of which is fixed within the yokes 4 and 5, and is used to print dots on paper (not shown). 3
is an armature fixed to the lower side of the leaf spring 2, 6 is a core yoke, and 7 is a magnet.

Further, 8 is a coil fitted into the protrusion 6a of the core yoke 6.

The magnetic flux of the magnet 7 flows from the yokes 5 and 4 through the spring 2 and into the core yoke 6 via the armature 3. The armature 3 is brought into close contact with the core yoke 6 by the attraction of this magnet, the spring 2 is deformed, and the spring 2 is used for printing. have energy. Printing is performed by energizing the coil 8 so as to generate a magnetic flux opposite to that of the magnet 7, canceling the attractive force of the magnet 7, and utilizing the deformation energy of the spring.

Note that in the figure, arrows indicate magnetic path loops. Second
The figure is a schematic diagram of this conventional plate spring assembly. The fulcrum portion 2b of the leaf spring 2 is fixedly held by the yokes 4 and 5. In order for the leaf spring 2 to have a predetermined springiness, a certain distance is required between the fulcrum part 2b and the fixed part 2a to the armature 3, and this distance ultimately determines the size of the print head. This is a contributing factor. In order to obtain a predetermined spring span in this way, not only does the head become large, but in the head structure shown in Fig. 1, the leaf spring 2, armature 3, yokes 4 and 5, and core yoke 6 are all connected to the magnetic path. Because the magnetic mass is large, the relatively large magnet 7
Is required. In particular, since the plate spring 2 is thin, its magnetic resistance increases. Therefore, it was necessary to improve the shape of either the yoke 4 or 5 so that it was extended so as to be adjacent to the armature 3, and to use it as an auxiliary magnetic path. Furthermore, because the magnetic path is large, power consumption for canceling the magnetic flux also increases.

[Purpose of invention]

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned prior art,
The purpose of the present invention is to provide a print head for a wire dot printer that is small and consumes little power.

[Summary of the idea]

In order to achieve this object, the present invention is characterized in that the armature fixed to the leaf spring is configured to extend in the yoke direction while providing a gap below the leaf spring.

In other words, this means that the fixed part 2 of the leaf spring 2
It can also be said that the structure is such that a notch is provided in the armature from the fulcrum part 2b side up to part a.

[Example of idea]

Embodiments of the present invention will be described below with reference to the drawings.

Note that the same parts as in the conventional example are given the same reference numerals.

FIG. 3 shows an assembly of the leaf spring 2 using the armature 12 according to the present invention, and FIGS.
FIG. 6 is an example of a magnetic circuit used in a printer head. Since the armature 12 shown in FIG. 3 has a notch up to the fixed portion 2a, it becomes a very compact leaf spring assembly with a predetermined spring span, making it possible to downsize the head. In other words, the presence of a notch means that the armature 12 is provided with an extending piece 12a that extends toward the yoke (indicated by 10 in FIG. 4, 13 in FIG. 5, and 14 in FIG. 6). I can do it.

FIG. 4 shows the head structure according to the first embodiment, in which the extending piece 12a faces the yoke 10 on the magnet 7 in a vertical positional relationship. The outer sides of the core yoke 6, magnet 7, and yoke 10 are covered with an aluminum case 8 attached for the purpose of heat radiation. The leaf spring 2 is
This aluminum case 8 and set plate 11
It is fixed at one end by.

In the head structure shown in FIG. 4, the magnetic flux of the magnet 7 mainly flows into the core yoke 6 through the yoke 10 and the armature 12, and the leaf spring 2 hardly forms a magnetic path. Furthermore, the fulcrum of the leaf spring 2 is placed outside the magnetic path, which stabilizes the operation and makes the magnetic circuit more compact.

FIG. 5 shows the print head structure according to the second embodiment. In this example, the leaf spring 2 is fixed by the yoke 13, and the extension part facing the extension piece 12a of the armature 12 at its tip end is fixed. 13a is provided, and in this example as well, magnetic flux hardly passes through the leaf spring 2, but instead flows from the extension portion 13a to the core 6 through the extension piece 12a.

Moreover, FIG. 6 is related to the third embodiment,
In this case, the yoke 14 has a hook-like shape as shown in the figure, and the extending piece 12a has its tip facing the hook portion on two sides.

In this example as well, the magnetic flux forms a closed loop without flowing through the leaf spring 2.

[Function and effect of the idea]

As explained above, according to the present invention, a closed magnetic path can be constructed without passing magnetic flux through the leaf spring that biases the wire, so there is no magnetic loss due to the leaf spring, and therefore the volume of the magnet can be reduced. This makes it possible to downsize the head as a whole when combined with the structure of the extending piece toward the yoke.

Furthermore, since the magnetic circuit becomes smaller, the power consumption required to cancel it can also be reduced, resulting in energy savings, and it is possible to provide a print head with excellent functionality by eliminating the drawbacks of the above-mentioned prior art.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway vertical sectional view showing a print head of a conventional wire dot printer;
FIG. 2 is a schematic diagram of the leaf spring assembly, FIG. 3 is a schematic diagram of the leaf spring assembly according to the present invention, and FIG. 4 is a first embodiment of a print head incorporating this leaf spring assembly. FIG. 5 is a partially cutaway longitudinal sectional view showing the second embodiment, and FIG. 6 is a partially cutaway longitudinal sectional view showing the third embodiment. be. 1... Wire, 2... Leaf spring, 6... Core yoke, 7... Magnet, 10, 13, 14...
Yoke, 12... Armature, 12a... Extension piece.

Claims (1)

[Scope of utility model registration request] In a head mechanism that deforms and urges a leaf spring with a wire fixed to its free end by the attraction force of a magnet, further cancels the attraction force of the magnet with an excitation coil, and prints using the deformation energy of the leaf spring. A print head for a wire dot printer, characterized in that an armature that is attached below a leaf spring and forms a closed magnetic path with a core yoke is provided with an extending piece extending toward the yoke and forming a gap with the leaf spring.