JPS5852928Y2 - printing magnet - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a printing magnet used in an impact type dot printing head or the like.

FIG. 1 shows an example of a dot print head suitable for implementing the present invention, and particularly shows a print magnet portion therein in a sectional view.

In the figure, 1 is an armature of a printing magnet to which the base end of a printing wire 2 is fixed to its free top, 3 is a leaf spring that supports the armature 1, and 4°5.6 forms a magnetic path of the printing magnet. 7 is a permanent magnet that generates a magnetic field for attracting the armature 1 toward the yoke 4 and deflecting the leaf spring 3; 8 is a permanent magnet that generates a magnetic field that cancels the magnetic field of the permanent magnet 7; This is a release coil that releases 1 from a restrained state.

During printing, a current is passed through the release coil 8, and the armature 1 is released from the restraint state as described above, and at the same time, the armature 1 is rotated by the strain energy of the bent leaf spring 3, and the printing wire is 2 forward.

At this time, in the printing magnet having this structure, the rotational fulcrum of the armature 1 is at one corner 4a of the end of the yoke 4 facing the suction action gap, as shown in FIG.

In the conventional printing magnet in which the rotational fulcrum of the armature 1 is located on a part of the yoke 4, a registration sheet 9 is placed between the armature 1 and the yoke in order to prevent fretting corrosion and wear of the fulcrum. It was inserted between 4.

However, in the past, even if the fulcrum part of the yoke 40 was rounded and finished so as not to form a corner, line contact would result, and the stress acting on the surface of the yoke 4 side of the regisial sheet 9 would increase, and the stress due to Hertzian contact would cause peeling wear. Therefore, the regisial sheet 9 had the disadvantage that the surface on the yoke 4 side was extremely worn compared to the armature 1 side.

The present invention aims to eliminate the above drawbacks, and will be described in detail below with reference to the drawings.

FIG. 3 shows an embodiment of the present invention, in which an elastic body 10 is provided at a corner of a yoke 4 that serves as a pivot point for the armature 1.

Therefore, the yoke 4 side of the regisial sheet 9 comes into surface contact due to the elasticity of the elastic body 10, and as a result, stress due to Hertzian contact is no longer generated.

Therefore, wear on the surface of the registration sheet 9 on the yoke 4 side is reduced, and its life is extended.

The elastic body 10 is not only made of rubber, but also polyamide and polyimide resins are suitable from the viewpoint of heat resistance and abrasion resistance.

As described above, according to the present invention, in the printing magnet which has an armature whose rotational fulcrum is a part of the yoke, and a registration sheet is inserted between the armature and the part of the yoke, The service life of the registration sheet can be extended, and the performance and reliability of the dot print head can be improved.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional side view showing an example of a printing magnet suitable for implementing the present invention, Fig. 2 is an enlarged view showing a part of Fig. 1 in detail, and Fig. 3 is an embodiment of the present invention. It is an enlarged view showing a part of in detail. 1... Armature, 4... Yoke,
9...Regisial sheet, 10...Elastic body.

Claims (1)

[Scope of utility model registration request] It has an armature whose rotational fulcrum is part of the yoke,
A printing magnet in which a registration sheet is inserted between the armature and a portion on the yoke, characterized in that an elastic body is provided on a portion of the yoke that serves as the rotational fulcrum.