JPH0225631Y2 - - Google Patents

Description

[Detailed Description of the Invention] (A) Technical Field of the Invention The present invention relates to a printing head for a wire dot printer, and particularly to the armature structure of a release type printing magnet.

(B) Background of the Technology In recent years, various dot printers have been developed and put into practical use as printers for various computer terminals, word processors, and the like.

Dot printers operate the print head to form a predetermined shape with a collection of dots to print characters, etc., so the dots can be combined freely and there are many types of characters, making it easy to create the types of characters needed for each field of use. It is very suitable and economical. In particular, as the use of devices as terminal devices such as office computers is expanding, there is a demand for high reliability of devices.

(C) Prior Art and Problems Hereinafter, the prior art will be explained using a wire dot printer as an example with reference to FIGS. 1 to 3. FIG. 1 is a plan view illustrating the outline of a wire dot printer to which the present invention is applied, FIG. 2 is a sectional view showing the print head in FIG. 1, and FIG. 3 is a
It is an A′ cross-sectional view.

As shown in Figure 1, the wire dot printer
A platen 10 is rotatably supported by a side frame 9. A printing paper 11 is inserted or wound around the platen 10, and the printing paper 11 is fed in the direction of arrow A in the figure by sprockets 12a, 12b, etc. On the other hand, on the front side of the platen 10, in the lower part of the figure, a carrier 13 is slidably fitted into a guide shaft 15 provided parallel to the platen 10; It is threadedly engaged with the feed screw 16. The feed screw 16 is connected to the motor 19 via a belt 17 etc., and therefore the feed screw 16 is connected to the motor 1
The carrier 13 can be moved in the directions of arrows C and D in the figure by rotating the carrier 9 in the forward and reverse directions.

An ink ribbon cassette 20 is mounted on the carrier 13, and an endless ink ribbon 20a is built into the ink ribbon cassette 20 with a portion thereof exposed to the platen 10 side. Further, a print head 21 is installed in the carrier 13 so as to be surrounded by an ink ribbon cassette 20, and the print head 21 is provided with a plurality of print magnets for forming prints by dots. As shown in Figure 2, the printing magnet has core 1.
A coil 2 is wound around the core 1, and an armature 3 is arranged so as to come into contact with the core 1. The armature 3 has a printing wire 4 fixed to its tip, and the armature 3 is made of a magnetic material as shown in FIG. It is locked as if being held by the Further, a recess 26 is carved in the rear of the amateur 3, and is loosely fitted into a protrusion 28 protruding from the cover 27.

A permanent magnet 22 is interposed between the yoke 7 and the yoke 8, and the side magnetic path member 6 and armature 3 described above are connected to each other.
Together, they form a loop-shaped magnetic path. Therefore, when the printing magnet is not operating, permanent magnet 2
Amateur 3 is attracted to core 1 by the magnetic force of 2. As shown in FIG. 2, the printing head 21 has a printing magnet that concentrates the printing wire 4 in the center, and a wire guide 2 that protrudes from the center.
3, the printing wires 4 are guided and aligned. The armatures 3 of the printing magnets are arranged radially as shown in FIG. Further, a coil spring 24 is in contact with the vicinity of the tip of the armature 3, and the pressing force is adjusted with a screw 25. This adjusts the attraction force between the core 1 and the armature 3, and adjusts the force with which the printing wire 4 protrudes from the wire guide 23. Furthermore, in the center of the print head 21, there is a ring-shaped oil-impregnated member 30 held by the block 29 and made of felt or the like impregnated with the lubricating oil of the coil spring 24. And again block 29
An oil absorbing member 31 made of cylindrical felt or the like is provided on the outer edge of the core 1 to prevent lubricating oil from penetrating into the core 1.

With such a configuration, when a current is applied to the coil 2 of the printing magnet of the printing head 21 so that the N and S poles of the permanent magnet 22 and the pole of the core 1 are opposite to each other,
The core 1 becomes an electromagnet and works to cancel the attractive force of the permanent magnet 22, and the armature 3 is activated by the energy stored by the coil spring 24.
In the figure, it jumps upwards. Then, the printing wire 4 also protrudes from the wire guide 23. In this way, while selectively driving the plurality of printing magnets in the printing head 21, the printing head 21 is moved together with the carrier 13 in the C and D directions as shown in FIG. 1, thereby performing a printing operation on the printing paper 11. I do. However, in the prior art, the core 1 and the armature 3 are flat and in wide contact with each other, and the lubricating oil impregnated around the coil spring 24 is not sufficiently absorbed by the oil absorbing member 31. The oil penetrates into the gap formed between the core 1 and the armature 3, and when the armature 3 is operated due to the adhesive force and surface tension of the oil, the armature 3 is not released, causing dots to fall out.

(D) Purpose of the invention The purpose of the present invention is to solve the above-mentioned drawbacks, and to provide a printing head which improves the structure of the armature and improves the reliability of printing.

(E) Structure of the invention In order to achieve the above object, the invention includes an armature made of a magnetic rigid body and having a printing wire at one end, and a core that is provided opposite to the armature and makes contact with the armature. a yoke, which includes an electromagnet having an electromagnet and a permanent magnet that generates a magnetic flux for attracting the armature so that the armature and the core are in contact with each other, and whose end face constitutes a mounting surface for the armature and which is formed on the same plane as the upper surface of the core. and a printing head comprising a spring whose one end is in contact with the armature and which is compressed when the armature is swung into contact with the core, and an oil-impregnated member impregnated with lubricating oil to be supplied to the spring. is a surface facing the aforementioned mounting surface, and the entire region facing the mounting surface is formed in a stepped shape with a predetermined depth with respect to the surface facing the core.

(F) Embodiment of the invention An embodiment of the invention will be described below with reference to FIG. 4. FIG. 4 is a side sectional view showing the main parts of the printing magnet according to the present invention. The same symbols throughout the figures indicate the same objects. In the figure, 32 indicates a stepped portion. As shown in Figure 4, in this invention,
A stepped portion 32 of a predetermined depth is provided on the entire surface of the end portion of the armature 3 that comes into contact with a yoke 8 which is a component of the yoke 7 of the printing magnet. By doing this, the part of the armature 3 that comes into contact with the yoke 8 is the end point indicated by arrow B. Yoke 8
Since the upper surface of the core 1 and the upper surface of the core 1 are configured to be on the same plane, the abutting portion between the core 1 and the armature 3 is also
Since the armature 3 is tilted, there is only one location shown by arrow C.

With this configuration, the contact between the core 1 and the armature 3 is not a surface contact as in the prior art, but a line or point contact, so even if the lubricating oil penetrates into the upper surface of the core 1 and coats it, the surface tension will be reduced. The influence of adhesive force is drastically reduced and the operation of Amateur 3 is no longer hindered.

(G) Effect of the invention As explained above, according to the present invention, by providing a stepped portion at the end locking part of the armature, malfunctions of the armature due to penetration of lubricating oil, which occur in the conventional technology, can be avoided. can be removed, making it possible to improve the reliability of printing.

[Brief explanation of the drawing]

FIG. 1 is a plan view illustrating the outline of a wire dot printer to which the present invention is applied, FIG. 2 is a sectional view showing the print head of FIG. 1, and FIG.
A' sectional view and FIG. 4 are side sectional views showing essential parts of the printing magnet according to the present invention. In the figure, 1 is the core, 2 is the coil, 3 is the armature, 4 is the printed wire, 6 is the side magnetic path member, 7 is the yoke, 8 is the yoke, 22 is the permanent magnet, 23 is the wire guide, and 24 is the 25 is a screw, 27 is a cover, 29 is a block, 30 is an oil-impregnated member, 31 is an oil-absorbing member, and 32 is a stepped portion.

Claims (1)

[Scope of Claim for Utility Model Registration] An armature 3 having a printing wire 4 at one end and made of a magnetic rigid body, an electromagnet having a core provided opposite to the armature and in contact with the armature, and the armature and the core. A permanent magnet 22 that generates magnetic flux to attract the amateurs into contact.
a yoke 7 whose front end constitutes an armature mounting surface formed on the same plane as the upper surface of the core; In the printing head, the armature 3 is a surface facing the mounting surface, and is a surface facing the mounting surface. A printing head characterized in that the entire area is formed in a stepped shape with a predetermined depth relative to the surface facing the core.