JPS6169469A - Dot printing head - Google Patents

Abstract

PURPOSE:To lower noise level, by forming an armature from a high-damping alloy consisting of a soft magnetic material so that vibration generated on collision of the armature is absorbed. CONSTITUTION:With the armature formed of a soft magnetic material consisting of 13-17% Cr, 1-4% of Al and the balance of Fe, the attraction and releasing thereof by turning ON and OFF a signal current supplied to an exciting coil 8 takes place extremely smoothly, and the noise generated on the collision of the armature 9 against an end face 12 of a yoke 7 is reduced to 50dB, which value is extremely low as contrasted to 75dB in the case of a conventional armature formed of a silicon steel plate.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the structure of a print head for a dot printer.

Various input/output devices are used as peripheral devices for computers, one of which is a printing device.

Printing devices can be broadly classified into impact type and non-impact type, and both are directly connected to terminal equipment to record various information.

The requirements for such a printer are that it should be capable of high-quality, high-speed printing, and that it should operate stably with little noise.

Figure 2 explains the printing operation of a dot line printer, in which a continuous paper 2 is running in contact with a platen 1, an ink ribbon 3 is placed in front of it with a small gap, and a continuous paper 2 is running in contact with a platen 1. It moves at a very small speed in a direction perpendicular to the direction in which the paper travels and is wound up.

Further, in front of it is a print head 5 equipped with a drive device for the print wire 4, and is configured to horizontally reciprocate by a morph.

That is, the print head 5 is composed of a plurality of print wire drive devices, and in response to a signal, a specific print wire protrudes and collides with the platen l.
ink is printed on continuous paper 2.

In this way, a plurality of printing wires (for example, 24) selectively protrude and hit the platen 1 in response to a signal, thereby printing a character 1 figure, etc. However, there is a problem with such wire dot printers. The noise is generated when the printing wire hits the platen and when the armature with the printing wire is sucked into the yoke. The noise generated from printers exceeds 70 dB, and suppression of this noise has become a problem that requires an urgent solution.

[Conventional technology]

Figure 1 shows the structure of the printing section of a wire dot printer, and
A print head is constructed by arranging a plurality of such printing parts.

That is, an excitation coil 8 is provided at one end of a U-shaped yoke 7 formed with a permanent magnet 6 in the center, while a plate spring 10 with an armature 9 at its tip is connected to a side magnetic path 1.
1 and fixed to the yoke 7.

Further, a printing wire 4 is provided at the tip of the armature 9.

Here, the armature 9 has been made of a silicon steel plate, etc., and the permanent magnet 6 connects the side magnetic path 11 to the armature 9.
- Since a closed magnetic path passing through the yoke 7 is formed, the armature 9 is attracted to the end surface 12 of the yoke 7.

When a signal current is applied to the excitation coil 8 in this state, the resulting magnetic field is designed to cancel out the magnetic flux forming the conventional closed magnetic path, so the armature 9 is in an attracted state due to the elasticity of the leaf spring 10. The printing wire 4 is released and restored, and due to this restoring force, the printing wire 4 protrudes and hits the platen to perform printing.

Next, when the signal current to the exciting coil stops, a closed magnetic path is again formed by the permanent magnet 6, and the armature 9 is attracted to the end face 12 of the yoke.

Here, the noise of a wire dot printer is generated not only when the printing wire 4 hits the platen, but also when the armature 9 is attracted to the end surface 12 of the yoke and collides with the end surface. This is a drawback.

[Problem that the invention seeks to solve]

As described above, in a wire dot printer, it is a problem to suppress the noise generated when the armature provided with the printing wire collides with the end surface of the yoke forming the printing section.

[Means for solving problems]

The above problem is that there is a permanent magnet at one end of the yoke equipped with an electromagnet, and a closed circuit is formed by the armature held by a leaf spring, and when the electromagnet is energized, the magnetic field passing through the armature is canceled out and the armature is attracted. A print head for a dot printer that performs printing by releasing the wire and protruding a wire provided on the armature by the elasticity of a plate spring, characterized in that the armature is made of a soft magnetic material having a soundproofing effect. This can be solved by

[Effect]

The present invention absorbs vibrations generated when the armature collides by forming the armature with a vibration-proof alloy made of a soft magnetic material, thereby reducing the noise level.

The anti-vibration alloy is a metal material that itself has a high damping ability against vibrations, and ferromagnetic, twin-crystal, dislocation-type, etc. are known. (References: Japan Institute of Metals Research, Metals Handbook, 9
(Page 71) In other words, a typical ferromagnetic material is a ferromagnetic material with a composition of 12Cr-2Al-86Fe called Silentalloy, and when external stress is applied, the direction of the spontaneous magnetization forming the domains changes. It absorbs vibrational energy by changing its shape.

The present invention uses such a ferromagnetic anti-vibration alloy to form an armature to reduce the noise level generated during a collision.

〔Example〕

In the present invention, the armature is formed using a soft magnetic material consisting of 13 to 17% Cr, 1 to 4% AI, and the remainder Fe. Experiments have shown that if the composition ratio of Cr is more or less than this, sufficient soundproofing effect is not achieved. On the other hand, AI has a composition ratio of 1
% or less, a sufficient soundproofing effect cannot be obtained, and if it is 4% or more, the saturation magnetic flux density decreases, making it impractical.

Here, we will discuss the case where the armature 9 is formed using a soft magnetic material of 15Cr-3AI-82Fe.
The attraction and release operations caused by ON and OFF of the signal current to the excitation coil 8 are extremely smooth, and the noise generated when the armature 9 collides with the end face 12 of the yoke 7 is reduced compared to the conventional silicon steel plate. Compared to the case of 75 dB, this was reduced to 50 dB, and a remarkable effect could be obtained.

〔Effect of the invention〕

As described above, the present invention was made to reduce the noise generated when a wire dot printer operates.
By constructing the armature with a soundproofing material made of soft magnetic material, it is possible to reduce the noise level.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of a printing section of a wire dot printer, and FIG. 2 is a plan view illustrating the configuration of the wire dot printer. In the figure, 4 is a print wire, 5 is a print head, 6 is a permanent magnet, 7 is a yoke, 8 is an excitation coil,
9 is the armature, 10 is the leaf spring,
12 is an end surface.

Claims (2)

[Claims] (1) There is a permanent magnet at one end of the yoke with an electromagnet,
A closed circuit is formed by the armature held by the leaf spring, and the electromagnet is energized to cancel the magnetic field passing through the armature, releasing the attraction of the armature, and the elasticity of the leaf spring causes the wire attached to the armature to protrude. 1. A print head for a dot printer, wherein the armature is made of a soft magnetic material having a soundproofing effect. (2) Armature is 13-17% chrome, 1-4%
The print head for a dot printer according to claim 1, characterized in that it is formed using a soft magnetic material made of aluminum and residual iron.