JPS6015468B2 - dot print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic leakage type dot print heads.

Conventionally, in ink-pact type dot print heads, the magnetic circuit of the electromagnet uses ferromagnetic material for the core, yoke, and armature to form a closed magnetic path to prevent leakage of magnetic flux as much as possible, and the armature gap is used to attract the electromagnet. It was used by placing it in a strong area.

This will be explained below according to the drawings.

FIG. 1 is a diagram showing the relationship between the armature gap of an electromagnet having a closed magnetic path and the attractive force. In order to obtain the desired ink compaction force, the left portion where the attractive force is strong is used.

Therefore, as is clear from the figure, even if the armature gap is slightly different, the suction force is considerably different, causing a difference in the impact force for each dot, and therefore,
There was a drawback that there was a difference in print density for each dot.
Therefore, it is necessary to accurately adjust the armature gap for each dot, which requires a lot of man-hours, and also requires a large number of parts, resulting in high costs. Therefore, the present invention provides a dot print head of a magnetic leakage type and a simple structure made of plastic molding.

This will be explained below according to the drawings.

FIG. 2 is a front view of the magnetic head according to the present invention, and FIG. 3 is a sectional view taken along line AA' in FIG.

In the figure, numeral 1 is a dot printing member having a hard substance attached to its tip by plating or the like. 2 has the dot printing member 1 at its tip, is divided into two parts near the center, and is joined at the other end, and has an armature 3 made of a ferromagnetic material.
A support member 6 is molded integrally with the hammer 2 from plastic or the like and has a hinge portion 5 extending from the end to the bifurcated center of the hammer 2.
7 is a screw hole for fixing the supporting member 4 to a carrier (not shown), 7 is a coil provided corresponding to the armature 3, and a filler 8 is E, which is an eboxy filler, for example.
It is fixed to the support section 4 using a product called STYCAST manufactured by RSON & CUMING.

Next, the operation of the present invention will be explained.

When the coil 7 is not energized, a portion of the armature 3 is loosely inserted into the center hole of the coil 7 by the hammer 2.
When the coil 7 is now energized, the armature 3 is attracted and moves into the coil, causing the hinge portion 5 to bend. Therefore, the hammer 2 rotates clockwise and the dot printing member 1 protrudes to print dot characters on a printing paper (not shown).

Next, FIG. 4 is a diagram showing the relationship between the armature gap and attractive force of the magnetic leakage electromagnet used in the present invention. As is clear from the figure, the attractive force is not greatly influenced by the armature gap.

In other words, magnetic leakage electromagnets use an air-core coil made of ferromagnetic material with no magnetic path, and an armature is placed near or inside the air-core coil, and the current flowing through this air-core coil and the leakage caused by this are This armature is attracted by the force generated by the interaction with the magnetic flux.
Since there is no so-called opposing magnetic pole, it is possible to reduce the change in leakage magnetic flux with respect to the amount of movement of the armature that moves the armature gear, and therefore the change in the attractive force with respect to the amount of movement of the armature. can. Therefore, it is possible to provide a dot print head with uniform print density for each dot without having to accurately adjust the armature gap of the electromagnet corresponding to each dot.

As described in detail above, according to the present invention, a dot printing member having a hard substance adhered to its surface is integrally molded at one end, and an armature made of a ferromagnetic material is provided at the other end using iron. The armature gap can be reduced by providing a hammer formed by inserting the hammer, a supporting part formed integrally with the hammer and extending from the other end of the hammer, and a coil integrally supported by the supporting member with a filler or the like. It is possible to construct a dot print head that does not require accurate adjustment, and it is also possible to provide a dot print head with a simple structure.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the armature gap and attraction force of a conventional electromagnet having a closed magnetic path, FIG. 2 is a front view of a dot print head according to the present invention, and FIG.
-A' sectional view, FIG. 4 is a diagram showing the relationship between the armature gap and attractive force of a magnetic flux leakage type electromagnet. 1... Dot printing section village, 2... Hammer, 3. ．．・．． ．．・Armature, 4...Support member, 5...
...Hinge part. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A dot printing member having a hard substance adhered to its surface, a hammer having one end supporting the dot printing member and an armature made of a ferromagnetic material inserted into the other end, and a hammer formed integrally with the hammer. A supporting member having a flexible hinge extending from the other end of the hammer is integrally molded with a non-magnetic material, and an air core coil for attracting the armature is fixed to the supporting member by molding or the like, A magnetic leakage type dot print head characterized in that the armature is disposed near or inside the air core coil.