JPS58131073A - Print head for dot printer - Google Patents

Abstract

PURPOSE:To prevent the abnormal motion of an armature and perform a reliable printing through a simple constitution, by constituting a device such that the armature are supported by a linear elastic member on a support member, and a printing is conducted based on the twist strain of the elastic member. CONSTITUTION:A plurality of armatures 11 are located to a support member 7, a print wire 12 is secured to the one end of the armature 11, and the other end is pivotally supported to the support member 7 with the aid of an elastic member 9. The armatures 11 are attracted through a magnetic force of a permanent magnet 5, and a twist strain ais produced to an arm aprt 9c positioned between a first part 9a and a second securing part 9b of the elastic member 9. An electromagnet 4 is then excited to erase the magnetic force of the permanent magnet 5 agaisnt the armature 11, the armatures 11 are turned counterclockwise centering about the arm part 9c through the force of the twist strain accumulated in the arm part 9c, and this pushes out the print wire 12 to perform a printing.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD This invention relates to a print head for a release type dot printer.

BACKGROUND OF THE INVENTION In a release type print head of this type, an armature having a print wire is supported by an elastic member. Usually, the armature is 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 energized, the magnetic force of the permanent magnet is canceled and the armature is released from the attraction line, and the armature is further driven by the elastic return force of the elastic member, causing the printing wire to protrude and print. is now being carried out. In such a print head, when the armature moves and returns, the armature does not make any necessary movements.
It is necessary to restrain that movement so that it does not occur.

For this reason, conventional IEs use a cross between a leaf spring and a wire spring as an elastic member to support the armature, and the driving force is obtained from the spring, so that the force that causes the armature to move erratically is applied to the wire spring. Some devices are designed to act as a tensile force. However, with this configuration, it is necessary to assemble a leaf spring and a wire spring to each armature, which makes the assembly troublesome, and also has the disadvantage that the number of parts increases and the print head becomes larger. existed.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a print head that can eliminate the above-mentioned defects, reduce the number of parts, facilitate assembly, and reduce the size of the print head.

EXAMPLE Hereinafter, an example 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 core 2 and the coil 3 constitute an electromagnet 4. An annular permanent magnet 5 is fixedly arranged on the front outer peripheral side of the head base 1, and an electromagnet device 6 is constituted by this permanent magnet 5 and the electromagnet 4. Further, a support member 7 made of a magnetic material is fixedly arranged on the front surface of the permanent magnet 5, and the support member 7 includes a main yoke portion 7a having an annular shape and a main yoke portion 7a as shown in FIGS. 2 and 3. and a sub-yoke portion 7b integrally formed on the front surface of the main yoke portion 7a and extending toward the center.

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. 15, each of the large number of armatures 11 has a through hole 11a at its base end, and a printing wire 12 is fixed to the tip thereof. Those armatures 11 are
The through hole 11a is located between each of the sub yoke portions 7b.
By fitting the elastic member 9 into the core 2
It is supported by the elastic member 9 in a state opposite to the distal end surface of. 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 of the first elastic member 9 to the adjacent second fixed portion 9b.
c 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.

A front cover 14 is arranged and fixed on the front surface of the support member 7 so as to hide each armature 11 and the sub-yoke portion 7b. And always (this is Eicha 11, Core 2)
A magnetic path is formed that passes through each of the two, thereby attracting the armature 11 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.
2 can pass through the guide tube 15 while being guided and project forward.

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

Now, the print head configured 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 retreats to the inoperative position, and torsional strain occurs in the arm portion 9c between the first fixed portion 9a and the second fixed portion 9b of the elastic member 9.

Next, when the coil 3 corresponding to one of the armatures 11 is selectively energized, the armature 1
1 is canceled, the armature 11 is released, and the armature 11 is rotated counterclockwise in FIG. 1 about the arm 9c due to the torsional strain stored in the arm 9C. This causes the printing wire 12 to protrude and dot matrix printing is performed.

Thereafter, when the current is cut off, a magnetic path by the permanent magnet 5 is formed again, 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 fixed by the second fixing part 9b, and the elastic member 9 is fixed to the sub-yoke part 7b of the armature 11. Since only a very small gap is formed between them, the elastic member 9 is restrained from any movement other than twisting movement. Therefore, armature 1
1 is prevented, the armature 11 efficiently performs only the required movement, and correct printing is performed.

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 is simplified. can do.

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 illustrated in the embodiments, the present invention supports an armature on a linear elastic member on a support member, allows the elastic member to move only due to torsional strain, and moves the elastic member based on the torsional strain. By configuring it so that printing is performed at the same time, it is possible to prevent incorrect movement of the armature and perform correct printing, and the structure is simplified, reducing the number of parts, making assembly easier, and making the print head smaller. Demonstrate the excellent effects that can be achieved.

[Brief explanation of the drawing]

The drawings show a print head that embodies the present invention; FIG. 1 is a cross-sectional view showing the whole, FIG. 2 is a partially cutaway front view, and FIG. 3 is a partially enlarged view showing the state in which the armature is supported. A front view, FIG. 4 is a sectional view showing the mounting state of the elastic member, and FIG.
The figure is a sectional view showing the supported state of the armature. Electromagnet 4, permanent magnet 5, electromagnet device 6, support member 7, support groove 8, first fixed part 9a, second fixed part 9b, arm part 9
c, armature 11, through hole 11a, printing wire 12° Patent applicant Japan Communication Technology Co., Ltd. Brother Industries, Ltd. Representative Patent attorney Hironobu Onda Figure 1 Figure 2 Figure 4 Figure 5 T7a

Claims (1)

[Claims] 1. A support member (7) and a plurality of armatures (
11) Printing wire (
12); a linear elastic member (9) rotatably supporting the other end of the armature (11) with respect to the support member (7); provided corresponding to each armature (11); In a print head of a dot printer comprising an electromagnetic device (6) having a permanent magnet (5) and an electromagnet (4) for selectively actuating an armature (11), the elastic member (9) is arranged such that the armature (11) The first fixed part (9
a); an arm portion (9c) extending continuously from the first fixed portion (9a) and acting as a rotation center of the armature (11); and an arm portion (9c) extending continuously from the arm portion (9c). and a second fixed part (sb) fixed to the supporting member (7), and the armature (11) is always attached to the arm of the elastic member (9) by the magnetic force of the permanent magnet (5). The corresponding electromagnet (4) is biased while causing torsional strain in the part (9c).
) is excited, the magnetic force of the permanent magnet (5) against the armature (11) is canceled, and the print head is driven by torsional strain stored in the arm (9c). 2. The print head for a dot printer according to claim 1, wherein the linear elastic member (9) is arranged in a ring shape on the circular support member (7). 8 The elastic member (
The through hole (11a) into which the support member (9) is inserted is
7) A print head for a dot printer according to claim 1, wherein a support groove (8) into which the elastic member (9) is inserted is provided at the peripheral edge of the dot printer.