JPS6232856Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a print head for, for example, a dot printer.

Conventionally, an electromagnet of a printing head whose armature rotates to perform a printing operation has a structure shown in FIG. 1 or 2. That is, in FIG. 1, the rear end of the armature 1 is disposed in contact with the yoke 2, and is elastically crimped with a spring plate 3 from the upper surface of the rear end.
Fig. 2 shows a structure in which the yoke 4 is made thinner to a certain extent, and the rear end 5a of the armature 5 is made to protrude from the yoke 4. One end of a spring 6 is attached to the rear end 5a and swings about a portion 4a supported by the yoke 4 as a fulcrum. However, in the structure shown in FIG. 1, the contact area between the armature 1 and the yoke 2 is small, so the magnetic transfer efficiency from the yoke 2 to the armature 1 is poor, and the structure shown in FIG. When the area is increased, the inertia of the armature increases, which reduces the response characteristics, that is, the printing speed, and also increases the number of parts, resulting in higher costs.

The present invention was developed in view of the above circumstances, and its purpose is to increase the magnetic transfer efficiency with a relatively simple configuration, minimize the increase in armature inertia, and reduce the number of parts. The object of the present invention is to provide a print head that can reduce costs.

The present invention will be explained below based on an embodiment shown in FIGS. 3 and 4. In FIGS. 3a and 3b, one end 11a of the yoke 11 constituting a part of the electromagnet 10 is formed outward in an L-shape, and the rear end of the armature 12 is supported on the yoke 11. It is becoming more and more common. That is, on the upper surface of the yoke 11 that supports the rear end of the armature 12, a gap g is provided rearward from the rear end of the armature 12, as shown in FIG. A recess 13 is carved therein. One end 13a of this recess 13 serves as a fulcrum on which the armature 12 rotates.
This has the effect that the radius of rotation is shorter than when the rear end of the armature 12 is used as a fulcrum, so that inertia can be reduced. On the other hand, the fact that the other end 13b of the recess 13 is positioned rearward from the rear end of the armature 12 does not impede the rotation of the rear end of the armature 12 when the armature 12 rotates about the one end 13a of the recess 13 as a fulcrum. It is intended to do so. Note that the depth d of the recess 13 may be set to such an extent that the rotation of the rear end of the armature 12 is not hindered. Reference numeral 14 denotes a positioning member located on one end 11a of the yoke 11 for positioning the rear end of the armature 12.
5 and is configured to be fixed with a mounting screw 16. Note that 17 is a printing needle that is provided in contact with the tip of the armature 12 and performs printing by energizing and deenergizing an electromagnet.

With this configuration, the engagement area between the armature and the yoke is increased, increasing the efficiency of magnetic transfer, and the rotation range of the armature is also shortened, making it possible to reduce inertia. Therefore, the attraction energy of the electromagnet can be efficiently converted into printing operation, and the response characteristics, that is, the printing speed can be improved.

Although one embodiment of the present invention has been described using a spring plate as a vibration prevention means when the armature rotates, this is not the gist of the present invention, and a coil spring as shown in FIG. A rubber bush (not shown) or the like may also be used.

Furthermore, in the above embodiment, the printing head for one printing needle was explained, but the pole piece,
By integrally forming the yoke according to the required number of printing needles and by carving a ring-shaped recess on the top surface of the yoke, the number of parts can be significantly reduced, and it can also be formed in combination due to its characteristics. Performance equivalent to that of electromagnets can be obtained. Furthermore, the shape of the recessed portion is not limited to the shape shown in FIG. 4; for example, as shown in FIG. However, the same effect as described above can be obtained.

As explained above, according to the present invention, it is possible to increase the magnetic transfer efficiency without significantly increasing the inertia of the armature, and the number of parts is reduced, resulting in cost reduction. It is.

[Brief explanation of the drawing]

1A and 2B and 2A and 2B respectively show a conventional printing head, in which a is a plan view, b is a longitudinal sectional front view, and FIGS. 3A and 3B show an embodiment of the present invention. In this figure, a is a plan view of the printing head, b is a longitudinal sectional front view thereof, FIG. 4 is an enlarged front view showing the main parts thereof, and FIG. 5 is an enlarged front view showing another embodiment of the print head. 12... Armature, 17... Printing needle, 1
1, 11'... Yoke, 13, 13'... Missing part (recessed part or notch), 14... Positioning member.

Claims (1)

[Scope of utility model registration request] An electromagnet, a yoke provided outside the electromagnet in parallel with the iron core of the electromagnet, and an armature that contacts a predetermined position of the yoke and is arranged to be rotatable about the contacted position as a fulcrum; In a printing head in which a tip of the armature moves a printing wire to perform dot printing by attracting the armature with an electromagnet, the surface of the armature facing the yoke is flat;
A rotation fulcrum is provided at a position distal by a predetermined distance from the rear end, and the yoke is directed toward the rear end of the armature from a position where it contacts the rotation fulcrum of the armature to a position outside the rear end. A printing head characterized by having a groove that allows rotation of the armature.