JPH0151348B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD This invention relates to print heads for open-ended dot printers.

BACKGROUND OF THE INVENTION In this type of open print head, an armature with a print wire is supported by an elastic member. The armature is always placed in the suction position by the magnetic force of the permanent magnet against the elasticity of the elastic member, and the printing wire is placed in the standby position. When the electromagnet is excited, the magnetic force of the permanent magnet is canceled and the armature is released from the attracted state, and the armature is driven by the elastic restoring force of the elastic member, causing the printing wire to protrude and printing to be performed. There is. In such a print head, it is necessary to restrain the movement of the armature so that it does not move other than the required movement when the armature is driven and when it returns.

For this reason, conventionally, as an elastic member to support the armature, for example, a cross between a leaf spring and a wire spring is used, and the driving force is obtained from the leaf spring. There are things that are configured to act as a force. However, when configured in this way, it is necessary to assemble a leaf spring and a wire spring to each armature, which makes the assembly troublesome, and
The drawback was that the number of parts increased and the print head became larger.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a printing head that eliminates the above-mentioned defects, reduces the number of parts, facilitates assembly, and reduces the size of the printing head.

Embodiment Hereinafter, an embodiment embodying the present invention will be described based on the drawings.A large number of cores 2 are integrally protruded at equal intervals from the front inner circumferential side of an annular head base 1 made of a magnetic material. It is formed. A coil 3 is wound around the outer periphery of each core 2.
and the coil 3 constitute an electromagnet 4. An annular permanent magnet 5 is fixedly arranged on the outer peripheral side of the front surface of the head base 1, and an electromagnet device 6 is constituted by this permanent magnet 5 and the electromagnet 4. moreover,
A support member 7 made of a magnetic material is provided in front of the permanent magnet 5.
is fixedly arranged, and its support member 7 is formed integrally with a main yoke portion 7a having an annular shape and a front surface of the main yoke portion 7a as shown in FIGS. 2 and 3, and extends toward the center. and an extending sub-yoke portion 7b.

As shown in FIGS. 3 and 4, a support groove 8 is cut into the base of each of the sub-yoke parts 7b located at the peripheral edge of the support member 7 from the outer peripheral side thereof. A ring-shaped elastic member 9 made of wire is fitted into the support groove 8, and the elastic member 9 is arranged concentrically with the support member 7. The sub-yoke portion 7b and the elastic member 9 are fixed by laser welding or brazing, and 10 indicates the welded portion.

As shown in FIG. 5, a large number of armatures 11
Each has a through hole 11a at its base end, and a printing wire 12 is fixed to the tip. These armatures 11 are supported by the elastic member 9 in a state facing the tip end surface of the core 2 by fitting the elastic member 9 into the through hole 11a between the sub-yoke parts 7b. The armature 11 is welded and fixed to the elastic member 9 by laser welding or brazing at the center of its base end, and 13 indicates the welded portion. In addition, the elastic member 9 portion of the welded portion 10 is used as a second fixed portion 9b. Further, the armature 11 is rotatable with respect to an arm portion 9c that continuously extends from the first fixed portion 9a to the adjacent second fixed portion 9b of the elastic member 9, so that this arm portion 9c acts as the center of rotation of the armature 11. In addition,
Only a very small gap is provided between each armature 11 and each sub-yoke portion 7b.

Each of the armatures 11 and the sub-yoke portion 7b
A front cover 1 is provided on the front surface of the support member 7 so as to hide the
4 is fixed in position. A magnetic path passing through the support member 7, the armature 11, and the core 2 is always formed based on the magnetic force of the permanent magnet 5, so that the armature 11 is attracted to the end surface of the core 2. Furthermore, when the coil 3 of the electromagnet 4 is energized, the magnetic force generated thereby cancels out the magnetic path. A guide tube 15 is fixed to the center of the front surface of the front lid 14, and the printing wire 12 can pass through the guide tube 15 while being guided and protrude forward.

A substrate 16 on which an electric circuit is printed is fixed to the rear surface of the head base 1, and a heat sink 17 is further fixed to cover the substrate 16.

Now, the print head constructed as described above operates as follows. First, when the electromagnet 4 is not energized, the armature 11 is attracted to the tip end surface of the core 2 and biased by the magnetic force of the permanent magnet 5. In this biased state, the printing wire 12
is retracted to the inoperative position, and the elastic member 9
Torsional strain occurs in the arm portion 9c between the first fixed portion 9a and the second fixed portion 9b.

Next, when the coil 3 corresponding to one of the armatures 11 is selectively energized, the magnetic path for that armature 11 is canceled, the armature 11 is released, and the energy stored in the arm 9c is Due to the torsional strain, the armature 11 is rotated counterclockwise in FIG. 1 about the arm 9c. As a result, the printing wire 12 protrudes and printing by dot matrix is performed.

Thereafter, when the current is cut off, a magnetic path is again formed by the permanent magnet 5, the armature 11 is attracted and rotated, and the printing wire 12 is retreated.

In any of the above cases, the elastic member 9 does not perform any movement other than rotational movement due to torsional strain. That is, the elastic member 9 is fitted into the support groove 8 on the sub-yoke part 7b of the support member 7 on both sides of each armature 11, and is inserted into the second fixed part 9b.
Moreover, since only a very small gap is formed between the armature 11 and the sub-yoke portion 7b, the elastic member 9 is restrained from any movement other than torsional movement. Therefore, the armature 11 is prevented from moving inadvertently, and the armature 11 efficiently performs only the required movement, thereby ensuring correct printing.

Moreover, in the print head of this embodiment,
The armature 11 is supported by one elastic member 9 made of a wire arranged on the support member 7, and no other members are used, so the configuration can be simplified. A support groove 8 is provided which is cut from the outer circumferential side, and the linear elastic member 9 that supports the armature 11 is inserted and fixed into the support groove 8 from the outer circumferential side. Compared to the case where a through-hole is provided and the linear elastic member 9 that supports the armature 11 is inserted and fixed from the side into the insertion hole, the elastic member 9 is attached to the sub-yoke portion 7b.
can be easily assembled.

Note that the present invention is not limited to the above-mentioned embodiments, and it is possible to use elastic members that are divided for each armature and individually fixed to a support member, or to use a plurality of elastic members that are similarly fixed to support members. It is also possible to use a unit that supports the armature of the book.

Effects of the Invention As exemplified in the embodiments above, the present invention supports an armature on a linear elastic member on a support member, allows the movement of the elastic member only due to torsional strain, and allows movement of the elastic member based on the torsional strain. By configuring the printing head to perform printing, it is possible to prevent incorrect movement of the armature and perform correct printing, and also to simplify the structure and reduce the number of parts, and to downsize the printing head. Furthermore, the sub-yoke part is provided with a support groove cut from the outside, and the linear elastic member that supports the armature is fitted into the support groove from the outside and fixed, so that it does not penetrate the sub-yoke part from the side. An excellent result is that the elastic member can be easily assembled to the sub-yoke compared to the case where a linear elastic member supporting the armature is inserted into the insertion hole from the side and fixed. demonstrate.

[Brief explanation of drawings]

The drawings show a printing head embodying the present invention, in which FIG. 1 is a sectional view showing the whole, and FIG.
The figure is a partially cutaway front view, Figure 3 is a partially enlarged front view showing how the armature is supported, Figure 4 is a sectional view showing how the elastic member is attached, and Figure 5 is a sectional view showing how the armature is supported. It is. Electromagnet...4, Permanent magnet...5, Electromagnetic device...
...6, Support member...7, Main yoke part...7
a. Sub-yoke part...7b, Support groove...8, Elastic member...9, First fixed part...9a, Second fixed part...9b, Arm part...9c, Armature...1
1. Through hole...11a, printing layer...12.

Claims (1)

[Scope of Claims] 1. A support member 7 having an annular main yoke portion 7a and a plurality of sub-yoke portions 7b extending from the main yoke portion 7a toward the center; a plurality of armatures 11 disposed between the sub-yoke portions 7b; In the printing head of a dot printer, the printing head comprises a printing wire 12 fixed to one end of each armature 11, and a linear elastic member 9 rotatably supporting the other end of the armature 11 with respect to the support member 7, as described above. Each sub-yoke portion 7b has a support groove 8 cut from the outside, and the elastic member 9 is connected to a first fixed portion 9a to which the armature 11 is fixed, and a first fixed portion 9a that is continuous from the first fixed portion 9a. An arm portion 9c that extends and acts as a rotation center of the armature 11; and a second fixing portion 9b that extends continuously from the arm portion 9c and is fitted and fixed from the outside into the support groove 8 of the sub-yoke portion 7b. The armature 11 has an arm portion 9 of the elastic member 9.
A printing head for a dot printer, characterized in that it is biased while producing a torsional strain on its arm portion 9c, and is caused to move back by the torsional strain stored in its arm portion 9c. 2. A printing head for a dot printer according to claim 1, wherein the linear elastic member 9 is arranged in a ring shape on the annular support member 7. 3. A printing head for a dot printer according to claim 1, wherein the other end of the armature 11 is provided with a through hole 11a into which the elastic member 9 is inserted.