JPS6013829B2 - dot print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses the magnetic force of a permanent magnet to cause a hammer with a dot printing wire attached to its tip, and by energizing the electromagnet, cancels out the magnetic flux of the permanent magnet. The dot printing head prints dot characters using the reaction force of the dot printing head.

This will be explained below using the drawings. FIG. 1 is a side sectional view for explaining the structure of this type of print head, and FIG. 2 is a detailed perspective view showing a part of FIG. 1.

In FIGS. 1 and 2, 1 is a first plate forming a common magnetic path, and 2 is N cores (N=2, 3, 4, etc.) fixed to the upper surface of the first plate 1. , 3 is the first
a ring-shaped permanent magnet fixed on the upper surface of the plate; 4 a magnet coil mounted on the N cores 2; 5 a ring-shaped second plate fixed on the ring-shaped permanent magnet 3; 6; 7 is a spacer having a thickness to obtain a desired gap, and 7 is a plurality of hammers 7a divided approximately centripetally.
. . . A leaf spring having a diameter of 7n and laminated on the baser 6, 8 an armature fixed to the upper surface of each of the hammers 7a to 7n, and 9 a printing plate fixed to the tip of each armature 8. 10 is a yoke plate laminated on the leaf spring to form a magnetic path between the permanent magnet 3 and the armature 8; 11 is a yoke plate having a guide hole 11a for guiding the wire 9; A laminated guide frame, 12 is oil felt, and 13 is a mounting hole provided to pass each layer.

The operation of the dot print head in such a configuration will be briefly explained.

First, when the magnet coil is not energized,
The armature 8 is caused by the magnetic flux of the ring-shaped permanent magnet 3.
Because it is adsorbed to core 2. Each hammer 7a is held in a relaxed state.

Coil 4 according to the dot pattern of the next character to be printed.
When energized, the magnetic flux of the permanent magnet 3 passing through the core 2 around which the coil 4 is wound is canceled out.

Therefore, the corresponding one of the hammers 7a, . . . , 7n is released, and the wire 9 collides with the printing paper surface due to the reaction force.

This allows the desired dot characters to be printed, but normally one hammer is damaged after 200 million to 300 million operations.

3A to 3C are diagrams for explaining such a conventional hammer, in which A is a plan view, the opening is a sectional view taken along line A-A' of A, and C is a diagram showing its cross-sectional area.

As is clear from FIG. 3C, the hammer constructed in this manner has the same cross-sectional area from the end of the armature 8 onward. As a result of experiments, it has been found that when a hammer with such a configuration is swung, stress is concentrated at the joint 14 between the hammer 3 and the armature 8. Moreover,
Since the hammer 13 is bent between the front side of the armature 8, that is, the periphery of the leaf spring 7, stress parallel to the direction of movement of the hammer 13 is concentrated on the joint 14' on the periphery side of the leaf spring 7. As a result, a peeling force acts between the hammer 13 and the armature 8. The strength of the bonded portion 14 against peeling force is generally weak, and the bonded portion 14 will be damaged at this portion. Next, Fig. 4 A to C are the junction points 14.
A through hole 16 is provided in the hammer 15 to prevent stress from concentrating on the hammer 15. A is the plan view, and the mouth is B-B' of A.
In the cross-sectional view, C shows the cross-sectional area of the hammer 15 at A and the mouth. When the hammer 5 is constructed in this way, the cross-sectional area of the through hole 16 becomes extremely small, as is clear from FIG. 4C.
Therefore, when the hammer 15 is released, stress is concentrated in the area where the through hole 16 is provided. If the printing speed is increased or the printing power is increased, there is a drawback that this part will be damaged.

Therefore, the present invention provides a dot print head with a long hammer life.

This will be explained below using the drawings.

FIG. 5 is an explanatory diagram showing the hammer portion of the print head according to the present invention, where A is a plan view, the opening is a cross-sectional view taken along line C--C of A, and C is a diagram showing the cross-sectional area of the hammer 17.

As shown in FIG. 5A, the through hole 18 of the hammer 7 is extended to the vicinity of the periphery of the leaf spring 7 in order to prevent stress concentration.
Since the chisel is supported by at least two branched hammers 17, there is no place where the cross-sectional area of the hammer 17 becomes extremely small, as shown in Fig. 3C, and stress is concentrated at that place. There will be nothing left to do. In addition, FIG. 6 is a back view of the plan view of FIG. 5 A from the back.
The joint portion 14 on the peripheral side of the hammer 7 is joined over a portion protruding toward the through hole 18 side.

Therefore, since the hammer 17 is joined to the armature 8 over the portion that is substantially orthogonal to the plane in which it moves and protrudes toward the through hole 18, a tensile force acts between the hammer 17 and the armature 8. I will do it. Since the strength of the joint 14 against tensile force is usually strong, it is possible to prevent damage to the joint 14. Therefore, it is possible to provide a dot print head that extends the life of the hammer and can withstand high-speed driving.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view for explaining the structure of a spring-charged dot print head, Fig. 2 is a perspective view showing the relationship between the leaf spring, armature, and wire in Fig. 1 in detail, and Fig. 3 is a conventional dot print head. Figure 4 is a diagram showing a hammer with a small hole, Figure 5 is a diagram showing a hammer according to the present invention, and Figure 6 is the back side of the plan view shown in Figure 5A as seen from the hair. It is a diagram. 1...First plate, 2...Core, 3
...Permanent magnet, 4...Coil, 7...
・・・Plate spring, 8... Armature, 9""
"Wire. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A hammer, which is provided approximately centripetally from the periphery of a disc-shaped leaf spring and has an armature connected to the tip with a printing wire, is attracted by the magnetic force of a permanent magnet, and by exciting the electromagnet, the permanent In a spring charge type dot printing head that cancels the magnetic flux of a magnet and prints by the reaction force of the hammer, the hammer has a through hole provided in front of the joint with the armature so that the hammer is substantially in contact with the surface on which it moves. A dot printing head characterized by being joined to an armature over a portion that is perpendicular to the dot and protrudes toward the through hole side.