JPH078199Y2 - Wire print head - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] In the present invention, in a printer, a print head for printing by driving a print wire fixed to the tip of an armature, in particular, a spring is attracted by a permanent magnet, The present invention relates to a so-called spring-charged wire print head which is released by an electromagnet for printing.

[Conventional technology]

FIG. 5 is a side sectional view showing the structure of a conventional wire print head of this type.

In the figure, 1 is a base having a center pole 2 installed at the center, and a permanent magnet 3 and a spacer are provided at the end of the base 1.
4, the yoke 5 is sequentially stacked, the spacer 4 and the yoke 5
A leaf spring 6 is sandwiched between and by a cantilever shape.

An armature 7 is attached to the flexible portion of the leaf spring 6, faces the core 9 of the electromagnet 8, a print wire 10 is attached to the tip of the armature 7, and is guided to the platen side by a guide 11. .

The arrow A in the figure indicates the magnetic path of the magnetic flux attracted by the permanent magnet,
The arrow B indicates the magnetic path of the demagnetizing magnetic flux generated by the electromagnet.

With the above-mentioned configuration, in the above-mentioned conventional example, first, an attractive magnetic flux is formed in the magnetic path A which returns to the permanent magnet 3 again through the spacer 4, the yoke 5, the armature 7, the core 9 and the base 1 by the permanent magnet 3. Depending on the state, the armature 7 is attracted to the core 9 so that the leaf spring 6 is in a biased state and stores strain energy.

In this biased state, when the electromagnet 8 is excited to generate a demagnetizing magnetic flux in the opposite direction to the attracting magnetic flux, the force for attracting the armature 7 decreases, so that the leaf spring 6 is released and the tip of the armature 7 is released. Print wire attached 10
Projects from the guide and presses the ink ribbon and the print medium (not shown) against the platen to perform printing.

At this time, the degaussing magnetic flux flows in the magnetic path B in which the magnetic flux easily flows, avoiding the magnetic path in the opposite direction of the magnetic path A in which the attracting magnetic flux passes, which is difficult to flow.

[Problems to be solved by the invention]

However, according to the prior art with the above-mentioned configuration, the degaussing magnetic flux flows through the magnetic path B, but in reality, the degaussing magnetic flux flows through the armature and the core adjacent to this, or conversely, the degaussing magnetic flux from the electromagnet of another element. Flows in.
This is what is called magnetic interference.

FIG. 6 is a front view of a main part for explaining such magnetic interference in the conventional example, and a plurality of elements forming a print head (a group of parts for printing one pixel is called one element). The same applies to the following two elements a and b. The numbers in the figure are the same as those in FIG.
The individual components of the two elements are suffixed after the number
Distinguish by attaching a and b.

The interference of the element a with the element b when the elements a and b operate simultaneously will be described below.

When the electromagnet 8a is energized to operate the armature 7a, a part of the magnetic flux generated by this flows through the yoke 5 to the core 9b of the adjacent element b. This magnetic path is indicated by arrow C in the figure.
It is indicated by.

Since the magnetic path C flowing to the element b has a loop shape, the element b
The magnetic flux has the same direction as the magnetic path A of the attracted magnetic flux, and as a result, a current that cancels the magnetic flux of the magnetic path C is induced in the electromagnet 8b of the element b. The direction of the current is the same as the current for canceling the attracted magnetic flux.

Therefore, when the elements a and b operate simultaneously, the element b
The electric current flowing through the electromagnet 8b of the above increases compared with the case where the element b operates independently. This is magnetic interference.

The interference from the element b to the element a is similar, and the interference from other non-adjacent elements is also to some extent,
The same can be explained.

From the above, according to the prior art of FIG. 5, the magnetic path configuration of the degaussing magnetic flux is insufficient, there are many magnetic interferences, the electrical-mechanical energy conversion efficiency is poor, and the power consumption and heat generation are high.
There was a problem of poor efficiency.

In view of the above problems, the present invention solves the problem that the two magnetic fluxes of attraction and demagnetization change their directions in the same magnetic path, obtains a configuration with less magnetic interference, and has low power consumption, low heat generation, and high efficiency print head. The purpose is to provide.

[Means for solving problems]

In order to achieve the above object, the present invention provides a leaf spring supporting each armature by attracting each armature with an attracting magnetic flux generated by a permanent magnet at one end of a plurality of electromagnets arranged in the circumferential direction. By bending, the demagnetizing flux generated by energizing the electromagnet cancels the attractive magnetic flux of the permanent magnet to open the armature and restore the leaf spring, thereby driving the print wire fixed to the tip of the armature. In the wire print head, one end faces the side surface of the armature so as to form a magnetic path through which a permanent magnet is divided for each electromagnet and is arranged at the other end of each electromagnet, and a magnetic flux attracted by the permanent magnet passes through. In addition, the demagnetizing magnetic flux of each electromagnet and the first yoke disposed between the electromagnets with the other end facing the side surface of the permanent magnet are So as to form a magnetic path that, while one end connected to the other end of the electromagnet, characterized by comprising a second yoke extending in the direction orthogonal to the arrangement direction of the electromagnet.

[Action]

According to the present invention having such a configuration, when the electromagnet is not energized, the attraction magnetic flux generated from each permanent magnet causes the first yoke,
The armature corresponding to the electromagnet, and the magnetic path that returns to the permanent magnet via the core of the electromagnet, and the degaussing magnetic flux generated from the electromagnet when the electromagnet is energized for driving the printing wire, passes through the armature from the second yoke and the electromagnet. And a magnetic path returning to the core of.

Therefore, according to this, since the permanent magnet divided for each electromagnet is provided at the other end of each electromagnet, the permeance seen from the electromagnet is reduced, and therefore the demagnetizing magnetic flux generated from the electromagnet is almost the attraction magnetic flux. Since it does not pass through the magnetic path and the magnetic flux is prevented from flowing out in the adjacent armature direction, magnetic interference can be significantly reduced.

In addition, since the permanent magnets are separately provided for each electromagnet, the magnetic flux is less sneak in in the direction of the adjacent electromagnets, so that the armature can be released with low power consumption, low heat generation and high efficiency. By arranging the permanent magnet at the other end of the electromagnet, the attraction magnetic flux of the permanent magnet can be canceled at a position where the magnetic flux density of the demagnetization flux by the electromagnet is high, and the armature can be released at high speed. .

〔Example〕

 Embodiments will be described below with reference to the drawings.

FIG. 1 is a side view of an essential part showing an embodiment of the present invention, and FIG. 2 is a front view of the same, showing the structure of one element. Also,
FIG. 3 is an exploded perspective view showing the overall structure of the same embodiment.

In the figure, 12 is an armature, 13 is a printing wire, and the printing wire 13 is fixed to one end of the armature 12, and when the armature 12 rotates, it strikes a medium through an ink ribbon (not shown) to form pixels. To print.

14 is a base, 15 is a permanent magnet, 16 is an electromagnet, 17 is an electromagnet 16
In the core, a plurality of electromagnets 16 are circumferentially arranged inside the base 14, and the electromagnets 16 are divided for each electromagnet 17, and between the other end of the core 17 of each electromagnet 16 and the base 14. It is fixed in place.

Reference numeral 18 denotes a yoke (first yoke) having one end facing the side surface of the armature 12 and the other end facing the side surface of the permanent magnet 15, and the yoke 18 is positioned between the electromagnets 16 so as to be located between the electromagnets 16. It is formed integrally with.

Reference numeral 19 denotes an arm portion (second yoke) having one end facing the armature 12 and the other end connected to the other end of the core 17 of the electromagnet 16, and the arm portion 19 extends in a direction orthogonal to the arrangement direction of the electromagnets 16. The yoke 18 is formed to project so as to extend, and the yoke 18 is set so as not to be present on the side surface of the arm portion 19.

Reference numeral 20 denotes a leaf spring sandwiched by the base 14 in a cantilever shape, and the armature 12 has an electromagnet at the free end of the leaf spring 20.
It is attached so as to face one end of 16 cores 17.

Further, an arrow D in FIG. 2 shows a magnetic path of an attracting magnetic flux by the permanent magnet 15, and an arrow E in FIG. 1 shows a magnetic path of a demagnetizing magnetic flux by the electromagnet 16.

With the above-described configuration, in the present embodiment, first, the permanent magnet 15 passes through the yoke 18, the armature 12, and the core 17 and the permanent magnet 15 is again used.
An attracting magnetic flux is formed in the magnetic path D returning to 15, and in this state, the armature 12 is attracted to the core 17, and the leaf spring 20 is biased to store strain energy.

In this biased state, when the electromagnet 16 is excited to generate a demagnetizing flux in the opposite direction to the attracting magnetic flux, the magnetic path E that passes through the arm portion 19 and the armature 12 and returns to the core 17 of the electromagnet 16
A degaussing magnetic flux is formed in the
The force of attracting 12 is reduced, so that the leaf spring 20 is released, the print wire 13 attached to the tip of the armature 12 projects, and the ink ribbon (not shown) and the print medium are pressed against the platen for printing.

At this time, since the permanent magnet 15 is interposed in the magnetic path D,
The permeance seen from the electromagnet 16 becomes smaller,
Most of the degaussing magnetic flux that is generated flows through the magnetic path E.

FIG. 4 is a front view of a main part for explaining the magnetic interference of the present embodiment, showing two adjacent elements a and b among a plurality of elements constituting the head. The numbers in the figure are the first
It is common with the figure. The individual components of the two elements are distinguished by adding suffixes a and b after the numbers.

The interference of the element a with the element b when the elements a and b operate simultaneously will be described below.

When the electromagnet 16a is energized to operate the armature 12a, as described above, the demagnetizing magnetic flux generated by the electromagnet 16a is mostly looped in the magnetic path E perpendicular to the circumference.

At this time, even if some outflowing magnetic flux is generated, these are separated by the adjacent element b and the lower part by the permanent magnet 15b,
The upper part has no armature yoke and the side part is provided with a guide path by the yoke 18, so that it stays within this range.
Therefore, the magnetic interference between the elements a and b is extremely small.

[Effect of device]

As described above, the present invention is divided into electromagnets,
In addition, one end is faced to the side surface of the armature and the other end is faced to the side surface of the permanent magnet so as to form a magnetic path through which a magnetic flux attracted by the permanent magnet is arranged. A first yoke disposed between the electromagnets and a magnetic path through which the demagnetizing flux of the electromagnets passes, and one end of the electromagnets is connected to the other end of the electromagnets and is orthogonal to the arrangement direction of the electromagnets. And a second yoke extending to the permanent magnet. When the electromagnet is not energized, the attractive magnetic flux generated from each permanent magnet passes through the first yoke, the armature corresponding to the electromagnet, and the core of the electromagnet to the permanent magnet. A return magnetic path and a magnetic path for degaussing magnetic flux generated from the electromagnet to pass through the armature and return to the core of the electromagnet when energizing the electromagnet for driving the print wire are formed. That.

Therefore, according to this, since the permanent magnet divided for each electromagnet is provided at the other end of each electromagnet, the permeance seen from the electromagnet becomes small, and therefore, the demagnetization flux generated from the electromagnet is almost the magnetic flux of the attractive flux. Since the magnetic flux does not pass through the path and the outflow of the magnetic flux in the adjacent armature direction is suppressed, the effect of significantly reducing magnetic interference can be obtained.

In addition, since the permanent magnets are separately provided for each electromagnet, the magnetic flux is less sneak in in the direction of the adjacent electromagnets, so that the armature can be released with low power consumption, low heat generation and high efficiency. By arranging the permanent magnet on the other end of the electromagnet, it is possible to cancel the attraction magnetic flux of the permanent magnet at a position where the magnetic flux density of the demagnetization magnetic flux by the electromagnet is high, and it is possible to release the armature at high speed. You can also get the effect.

[Brief description of drawings]

FIG. 1 is a side view of an essential part showing an embodiment of the present invention, FIG. 2 is a front view of the same, FIG. 3 is an exploded perspective view showing the entire structure of the same embodiment, and FIG. FIG. 5 is a side cross-sectional view showing a conventional example, and FIG. 6 is a front view showing the action of the conventional example. 12 ... Armature, 13 ... Printing wire 14 ... Base, 15 ... Permanent magnet 16 ... Electromagnet, 17 ... Core 18 ... Yoke, 19 ... Arm 20 ... Leaf spring

Claims (1)

[Scope of utility model registration request] 1. A leaf spring supporting each armature is bent by attracting each armature with an attracting magnetic flux generated by a permanent magnet at one end of a plurality of electromagnets arranged in the circumferential direction, In a wire print head for driving a print wire fixed to the tip of the armature by canceling the attraction magnetic flux of the permanent magnet with the demagnetization flux generated by energizing the electromagnet to release the armature and restore the leaf spring, The one end is faced to the side surface of the armature and the other end is formed so as to form a magnetic path through which a magnetic flux attracted by the permanent magnet is divided into permanent magnets divided for each electromagnet and arranged at the other end of each electromagnet. A first yoke disposed between the electromagnets so as to face the side surface of the permanent magnet, and a magnetic path through which a degaussing magnetic flux of each electromagnet passes. While one end connected to the other end of the electromagnet, the second yoke and the wire printing head, characterized by comprising a extending in a direction perpendicular to the arrangement direction of the electromagnet.