JPH05220985A - Wire dot printing head - Google Patents

Abstract

PURPOSE:To reduce magnetic interference at the time of simultaneous operation and to achieve the increase of a printing speed and the reduction of printing energy by constituting the support becoming the revolving fulcrum of an armature of a non-magnetic material and arranging a sub-core composed of a magnetic material to the outside of the support. CONSTITUTION:A support 24 is constituted of a non-magnetic material such as stainless steel and the revolving fulcrum P of an armature 22 is formed by the upper end surface of the support 14. Further, a sub-core 25 with predetermined height composed of a magnetic material such as iron is arranged to the outside of the support and the upper end surface thereof is opposed to the rear end part of the armature 22. The revolving operation of the armature at the time of the driving of a wire 23 is still more accelerated by the magnetic attraction force between the rear end part of the armature 22 and the sub-core 25 and a printing speed can be increased. At the same time, the exciting coil 13 is shortened as compared with a conventional one and, therefore, printing energy can be reduced. Since magnetic interference at the time of simultaneous operation is reduced to a large extent, it is unnecessary to increase the exciting current to the demagnetizing coil as is conventional.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a wire dot print head in a serial printer or the like.

[0002]

2. Description of the Related Art FIG. 5 is a longitudinal sectional view showing a conventional wire dot printing head, the structure of which will be described below. In the wire dot print head 50 shown in FIG. 5, 51 is a core, 52 is a degaussing coil wound around the core 51, 53 is a column that forms a pivot fulcrum P of an armature (described later), 54
Is packing, 55 is substrate, 56 is heat sink, 57 is base frame, 58 is first yoke, 59 is permanent magnet,
Reference numeral 60 is a second yoke, 61 is a bias leaf spring, 62 is a magnetic spacer, 63 is a first armature yoke, 64 is a second armature yoke, 65 is an armature fixed to the free end of the bias leaf spring 61, and 66 is The wire 67 fixed to the tip of the armature 65 is a head frame.

Next, the operation of the conventional wire dot print head 50 having the above structure will be described. First, when the degaussing coil 52 is not excited, the magnetic flux of the permanent magnet 59 forms a magnetic circuit that passes through the second yoke 60, the magnetic spacer 62, the first armature yoke 63, the armature 65, and the core 51. The armature 65 is attracted to the core 51 while biasing the bias leaf spring 61 by the magnetic attraction force. When the degaussing coil 52 is excited in this state, a magnetic flux in the opposite direction to the permanent magnet 59 is generated from the core 51, so that the magnetic flux of the permanent magnet 59 is canceled and the biased leaf spring 61 in the biased state is transferred to the core 5.
Be released from 1. At this time, the bending energy stored in the bias leaf spring 61 drives the wire 66 fixed to the armature 65 in the direction of the arrow in the figure to strike the print medium and the platen via an ink ribbon (not shown) to print. Print dots on the surface of the media. Subsequently, the armature 65 starts returning by the repulsive force at the time of printing,
After that, the magnetic flux of the permanent magnet 59 attracts the core 51 again to complete one printing operation.

[0004]

By the way, in recent years,
The demand for reducing the printing energy and improving the printing speed has become stronger and stronger. However, in the above-mentioned conventional wire dot print head 50, the printing speed can be improved by increasing the spring constant of the bias leaf spring 61, but if a plurality of wires 66 are driven simultaneously, as shown in FIG. , A part of the degaussing flux R ₁ of the core 51a flows into the adjacent core 51b through the first armature yoke 63 and the armature 65, and this interferes with the degaussing flux R _{2 of the} core 51b, so-called magnetic interference occurs, The release of the armature 65 in the core 51b becomes insufficient. Therefore, as a means for reducing the problem due to the magnetic interference, a method of increasing the exciting current to the degaussing coil 52 can be considered, but in that case, the down time due to heat generation of the print head increases, and as a result, The number of prints per unit time could not be increased significantly.

The present invention has been made in order to solve the above problems, and it is possible to reduce the magnetic interference during the simultaneous operation, and to improve the printing speed and the printing energy by the wire dot printing. The purpose is to provide a head.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and comprises a plurality of cores arranged annularly on a base frame, and degaussing wound around each of the cores. The coil, the armature fixedly attached to the free end of the bias leaf spring above each core, the wire fixed to the tip of the armature, and the armature rotation arranged outside the core. In a wire dot print head having a pillar that forms a dynamic fulcrum, the pillar is made of a non-magnetic material, and a sub-core made of a magnetic material is arranged outside the pillar.

[0007]

In the wire dot print head of the present invention,
Part of the degaussing magnetic flux of the core during excitation flows from the rear end of the armature to the sub core. As a result, a magnetic attraction force is generated between the rear end portion of the armature and the sub core, and the magnetic attraction force further accelerates the rotating operation of the armature.

[0008]

1 is a longitudinal sectional view showing a first embodiment of a wire dot print head according to the present invention. In the wire dot print head 10 shown in FIG. 1, 11 is a base frame 1
2 are annularly arranged cores on each of the two cores 11
A degaussing coil 13 is wound around each. The outer edge of the base frame 12 is sandwiched between the heat sink 14 and the first yoke 15. Above the first yoke 15, a permanent magnet 16, a second yoke 17, a magnetic spacer 18,
The first armature yoke 19 and the second armature yoke 20 are stacked in this order, and the fixed end of the bias leaf spring 21 is sandwiched between the second yoke 17 and the magnetic spacer 18. On the other hand, an armature 22 is fixed to the free end of the bias leaf spring 21, and a wire 23 is fixed to the tip of the armature 22. that time,
The armature 22 is arranged so as to face the upper end surface of the core 11.

In addition, in the wire dot print head 10 of this embodiment, each core 11 on the base frame 12 is
A support column 24 is disposed outside the. This pillar 24 is
For example, it is made of non-magnetic material such as stainless steel,
The upper end surface forms a pivot fulcrum P of the armature 22. The pillar 24 may be a ring-shaped integral type or a plurality of single bodies such as the core 11 arranged. Further, a sub-core 25 having a predetermined height is arranged outside the pillar 24. The sub core 25 is made of a magnetic material such as iron, and its upper end surface faces the rear end of the armature 22. Here, in this embodiment, the upper end surface of the sub core 25 is arranged lower than the upper end surface of the column 24, and a predetermined gap is formed between the bias leaf spring 21 supporting the armature 22 and the sub core 25. The predetermined gap is appropriately set in consideration of the rotation operation range of the armature 22 and the strength of the degaussing magnetic flux generated by the degaussing coil 13.

Next, the operation of the wire dot print head 10 of this embodiment having the above construction will be described. First, when the degaussing coil 13 is not excited, as shown in FIG. 2, the magnetic flux of the permanent magnet 16 causes the second yoke 17, the magnetic spacer 18, the first armature yoke 19, the armature 22, the core 11, the base frame 12, A magnetic circuit passing through the first yoke 15 is formed, and the magnetic attraction force generated at this time causes the armature 22 to be attracted to the core 11 while biasing the leaf spring 21 for bias.

When the degaussing coil 13 is excited from the above state, a magnetic flux in the opposite direction to the permanent magnet 16 is generated from the core 11, so that the magnetic flux of the permanent magnet 16 is canceled and the biasing leaf spring 21 in the biased state is removed. It is released from the core 11. At that time, as shown in FIG.
Because it flows to the base frame 12, the armature 22
A magnetic attraction force is generated between the rear end portion and the sub core 25. As a result, the normal rotational movement of the armature 22 due to the bending energy of the bias leaf spring 21 is further accelerated, thereby improving the printing speed.

Further, in the wire dot print head 10 of this embodiment, the problem of magnetic interference in the conventional example is alleviated for the following reasons. That is, in this embodiment, the magnetic resistance flowing from the rear end of the armature 22 to the sub-core 25 is smaller than the magnetic resistance flowing to the adjacent armature or core. That is, the sub core 25 fulfills the bypass function of the demagnetizing magnetic flux of the core 11. As a result, even when a plurality of wires 23 are driven simultaneously, the degaussing coil 1
The magnetic flux of 3 hardly flows to the adjacent armature or core, so that the magnetic interference is greatly reduced.

As described above, in the wire dot print head 10 of this embodiment, the rotating motion of the armature 22 when the wire 23 is driven causes the magnetic attraction force generated between the rear end of the armature 22 and the sub core 25. By further accelerating, the printing speed can be improved, and at the same time, the excitation time for the degaussing coil 13 can be shortened as compared with the conventional case, so that the printing energy can be reduced. Moreover,
In the present embodiment, since the magnetic interference during the simultaneous operation is greatly reduced, it is not necessary to increase the exciting current to the degaussing coil as in the conventional example. Further, if the printing speed is improved and the printing energy is reduced in this way, the heat generation of the print head is suppressed, and the down time is greatly shortened. As a result, the number of prints per unit time is significantly increased. It becomes possible.

FIG. 4 is a longitudinal sectional view showing a second embodiment of the wire dot print head according to the present invention. In the wire dot print head 10 shown in FIG. 4, the core 11 and the sub-core 25 made of a magnetic material are integrated with each other via the connecting piece 26, and the core 11 and the sub-core 25 are made of a non-magnetic material. A pillar 24 is provided. Further, the connecting piece 26 is provided at one end thereof with the first yoke 15 and the permanent magnet 1.
6 and 6, the outer peripheral surface of the wire dot print head 10 is formed. Here, in the present embodiment, since the magnetic flux of the core 11 and the permanent magnet 16 flows to each member through the connecting piece 26,
The base frame 12 is made of a non-magnetic material. The description of the operation of the wire dot print head 10 of the present example is omitted since it is the same as in the first embodiment.

[0015]

As described above, according to the wire dot print head of the present invention, the rotating motion of the armature during wire driving is further accelerated by the magnetic attraction force generated between the rear end of the armature and the sub core. By doing so, the printing speed can be improved, and at the same time, the excitation time for the degaussing coil can be shortened as compared with the conventional case, so that the printing energy can be reduced. Moreover, in the present invention, since the magnetic interference during the simultaneous operation is greatly reduced, it is not necessary to increase the exciting current to the degaussing coil as in the conventional example. Also,
When the printing speed is improved and the printing energy is reduced in this way, heat generation of the print head is suppressed, and the down time is greatly shortened. As a result, the number of prints per unit time is significantly increased. Is possible.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a wire dot print head according to the present invention.

FIG. 2 is an explanatory diagram of an operation during non-excitation.

FIG. 3 is an explanatory diagram of an operation during excitation.

FIG. 4 is a vertical cross-sectional view showing a second embodiment of the wire dot print head of the present invention.

FIG. 5 is a vertical sectional view showing a conventional example.

FIG. 6 is an explanatory diagram of a conventional problem.

[Explanation of symbols]

 10 Wire Dot Printing Head 11 Core 22 Armature 24 Strut 25 Sub-core P Rotation Support Point

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takanori Mimura 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (2)

[Claims] 1. A plurality of cores arranged annularly on a base frame, a degaussing coil wound around each core, and an upper portion of each core fixed to a free end of a leaf spring for bias. A wire dot printing head comprising: an armature arranged in the armature; a wire fixed to a tip of the armature; and a pillar arranged outside each core to form a pivotal fulcrum of the armature. Is a non-magnetic material, and a sub-core made of a magnetic material is disposed on the outer side of the supporting column of the wire dot printing head. 2. The wire dot print head according to claim 1, wherein an upper end surface of the sub-core is arranged lower than an upper end surface of the column.