JPS625074B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention biases a spring with a permanent magnet, cancels the magnetic field of the permanent magnet by energizing a degaussing coil, releases the biased spring, and drives a printed wire. This invention relates to a so-called spring-charged wire dot head.

Conventionally, in a dot head in which the tip of the armature rotatably supported the armature with the center of rotation serving as the center of impact, as shown in FIG. 5. Passing through the yoke 6, the armature 4 is normally attracted to the core 5 by the magnetic flux of the permanent magnet 1, and the leaf spring 7 is biased, but by energizing the coil 8, the magnetic flux of the permanent magnet 1 is extinguished. The printing wire 9 is erased and the armature 4 is released.
protrudes from the wire guide 10. At this time, the impact center point is 4b, and the rotation center is the core 5a. Since the core 5 and yoke 2 are manufactured by surface grinding, the deflection of the leaf spring 7 is determined by the dimension from the surface 4a of the armature 4 to the surface 7a of the leaf spring 7. However, as shown enlarged in Fig. 2 A and B, the armature 4, armature piece 11, and leaf spring 7 are silver-brazed with silver solder 12. Due to thermal deformation, the dimensions from the surface 4a of the armature 4 to the surface 7a of the leaf spring 7 vary, which leads to a drawback that the printing force varies.

In Figure 3, in order to suppress the variation in printing power mentioned above,
The armature 4 and the leaf spring 7 are fixed by laser welding, which causes very little deformation, but considering laser welding strength and manufacturing stability, it is necessary to position the leaf spring 7 on the facing surface of the armature 4 and the core 5. It was hot. In this case, due to the characteristics of the material, the leaf spring 7 has a lower saturation magnetic flux density than the armature 4 and core 5, and as a result, the permanent magnet cannot obtain sufficient attraction force, which is difficult to achieve high-speed printing. It was hot. Furthermore, in order to generate the biasing force of the leaf spring 7, the core 5 and the yoke 2 cannot be made on the same surface, and there is a drawback that surface grinding cannot be performed, which leads to an increase in manufacturing costs.

The present invention, in order to eliminate the above-mentioned drawbacks, relates to a structure that reduces variation in impact force without impairing high speed, and facilitates manufacturing, and will be described in detail below with reference to the drawings.

FIGS. 4A and 4B are a plan view and a side view showing essential parts of an embodiment of the present invention, in which a leaf spring 15 having a square hole 15a is fitted into a groove 13b provided in the rotational fulcrum of the armature 13, After further fitting the auxiliary plate 14 onto this, the leaf spring 15 and the auxiliary plate 14 are attached to the armature 1 by laser welding.
It is welded to 3. The leaf spring 15 is held between the yoke 2 and the yoke 3, and the end surfaces of the yoke 2 and the core 5 are made into the same plane by surface grinding. Therefore, the leaf spring 15 is biased by the thickness of the auxiliary plate 14.

With the above-described configuration, the leaf spring 15 can be laser welded to the armature 13, thermal deformation is extremely reduced, and surface grinding can be performed. Therefore, the biasing force of the leaf spring 15 can be controlled by the thickness of the auxiliary plate 14, the depth of the groove 13b, and the thickness of the leaf spring 15. Further, the thickness of the auxiliary plate 14, the depth of the groove 13b, and the thickness of the leaf spring 15 can be easily manufactured with high precision. Therefore, it is possible to suppress variations in the biasing force of the leaf spring 7 to small variations, thereby reducing variations in printing force.

Note that the other configurations are the same as those shown in FIG.

Further, in the embodiment described above, it is desirable that the auxiliary plate 14 be welded to the rotational fulcrum 5a at a position that is approximately distributed. As explained in detail above, there is an effect that variations in printing power can be reduced and manufacturing can be facilitated without impairing the high speed characteristic of the impact-centered type.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a conventional spring charge type dot head, Fig. 2 is a partially enlarged view showing the fixed portion of the armature, armature piece, and leaf spring in Fig. 1, and Fig. 3 is a cross-sectional view showing an example of a conventional spring charge type dot head. FIG. 4A and FIG. 4B are a plan view and a side view showing essential parts of an embodiment of the present invention. 1... Permanent magnet, 2... Yoke, 3... Yoke, 5... Core, 6... Yoke, 8... Coil,
9... Wire, 10... Guide, 11... Armature piece, 13... Armature, 14...
Auxiliary plate, 15...plate spring.

Claims (1)

[Claims] 1. An armature with a center of impact at its tip is attracted to the core by a permanent magnet, the leaf spring is biased, and the electromagnet is selectively energized to cancel the magnetic flux of the permanent magnet and release the corresponding armature. The restoring force of the leaf spring causes the armature to rotate with its center of rotation pressed against the outer corner of the core, and a so-called spring charge prints dots using a printing wire provided at the tip of the armature. In the type wire dot head, a groove is provided on the core side surface of the armature, and an engaging part that engages with this groove is provided in the leaf spring, and after the engaging part of the leaf spring is engaged with this groove. ,
Furthermore, the spring charge type wire dot head is characterized in that the armature and the leaf spring are fixed by engaging the auxiliary plate with the groove so that the grooved surface of the armature and the upper surface of the auxiliary plate are substantially flush with each other.