JPH06104366B2 - Impact record head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact recording head, and more particularly to an impact recording head that drives a recording member by a solenoid to strike a recording medium with the recording member to perform recording. is there.

[Prior Art] A wire dot recording head is known as a recording head of this type. In order to record characters and the like in this head, the pattern is expressed by a configuration of m × n dot matrix as shown in FIG. For this purpose, n wires arranged in the vertical direction (sub-operation direction) at a pitch of P ₂ are shifted horizontally in the horizontal direction (main operation direction) m times at a pitch of P ₁ while selectively changing the wires at each shift. The recording sheet is driven by each wire through the ink ribbon to perform the intended recording.

9 and 10 show a conventional structure of a suction type solenoid structure head as such a wire dot recording head.

In both figures, the reference numeral 1 is a tip guide, which is fixed to an intermediate guide 2 which is a front holder. The intermediate guide 2 has a notch 2a for a screw to be attached to a carriage (not shown).

A flexible printed board 3 is arranged behind the intermediate guide 2, and the board 3 is integrated with a heat dissipation plate 4. The heat dissipation plate 4 also serves as a spacer between the flexible printed circuit board 3 and the yoke 5 formed in an elliptic cylinder shape,
The heat of the yoke 5 is transferred to a back holder, which will be described later, and a material having a good thermal conductivity such as aluminum having a thickness of about 2 mm is selected.

A plurality of cores 6 are fitted and fixed to the yoke 5, and a bobbin 8 around which a coil 7 is wound is attached to the core 6. Two terminals 8a are provided on the bobbin 8 in a protruding manner, and the winding start portion and the winding end portion of the coil 7 are soldered and fixed to these terminals. The terminal 8a penetrates the yoke 5 and the heat dissipation plate 4 and is soldered and fixed to the flexible printed board 3.

Next, the reference numeral 9 is a rear guide, which is formed into a cylindrical shape as a whole, and includes the yoke 5, the heat dissipation plate 4,
The flexible printed circuit board 3 is arranged so as to penetrate the flexible printed circuit board 3 and be fitted into the intermediate guide 2. One end of a return spring 10 is fixed to the rear end of the rear guide 9.

On the other hand, the opening end of the rear end of the yoke 5 is closed by the auxiliary yoke 11. A circular opening is formed in the center of the auxiliary yoke 11, and the rear end of the rear guide 9 faces this portion. Further, the auxiliary yoke 11 is provided with a through hole 11a, and the post 8b projectingly provided on the rear end side of the bobbin 8 is fitted into the through hole 11a and protrudes to the back side of the auxiliary yoke 11.

Then, the rear end of the armature 14 is fitted to the post 8b,
An armature 14 is provided on the back surface of the auxiliary yoke 11 via a spacer 12 so as to be swingable about the rear end as a fulcrum.

The armatures 14 are radially arranged in a predetermined number corresponding to the number of wires, and the wires 22 are coupled to the tips thereof,
A plunger 13, which is a movable core, is projectingly provided in the central portion. In addition, the return spring 10 is elastically mounted between the free end of the armature 14 and the rear end of the rear guide 9, and the free end of the armature 14 is always attached to the rear guide 9 by the return spring 10. It is given a force in the direction away from the rear end.

The spacer 12 between the armature 14 and the auxiliary yoke 11 may cause wear due to contact between the auxiliary yoke 11 and the armature 14 or destabilize the motion of the armature 14 due to residual magnetism of the auxiliary yoke 11 which may cause problems when forming a closed magnetic circuit. It is provided to prevent it.

Next, a stopper 15 is arranged behind the armature 14,
The armature 14 is located at a position where it can come into contact with the free end side of the armature 14. The stopper 15 is fitted to the armature holder 16, and the tips of the arms of the armature holder 16 formed in a radial pattern press the base end side of the armature 14 against the auxiliary yoke 11. There is. Armature of each arm of this armature holder 16
The pressing force against 14 is provided by a similarly radial leaf spring 17 arranged behind the armature holder 16.

Further, a damper 18 is arranged behind the leaf spring 17.
The damper 18 is arranged in contact with the back holder 21 via a washer 19 and a spring washer 20. The back holder 21 is fixed to the intermediate guide 2 by screws 23 and covers the armature and the yoke as a whole.

The wire 22 is guided by the guides 1, 2, and 9 to prevent buckling, and the tips of the wires 22 are arranged in a line in the longitudinal direction.

In the above structure, the solenoid is composed of the core 6, the coil 7 and the plunger 13 as a movable core, and the magnetic circuit of the solenoid is composed of the core 6, the plunger 13, the armature 14, the auxiliary yoke 11 and the yoke 5.

With such a structure, at the time of recording, the coil 7 is selectively energized in accordance with the recording data, and the magnetic flux generated by the magnetomotive force of the coil 7 flows into the magnetic circuit. As a result, a magnetic force acts between the core 6 and the plunger 13, the plunger 13 is attracted to the core 6 side, and the armature 14 swings to the core 6 side against the elastic force of the return spring 10. Wire in conjunction with this
The dot 22 is projected to the left in FIG. 9, projects from the tip guide 1 and strikes the recording paper via an ink ribbon (not shown) to perform dot recording.

Thereafter, the coil 7 is de-energized, the attraction force of the core 6 disappears, and the armature 14 swings to the right in FIG.
Return to the initial position with 22.

[Problems to be Solved by the Invention] In the conventional wire dot head described above, all the constituent members of the magnetic circuit of the solenoid described above are composed of magnetic bodies having similar magnetic characteristics. Therefore, the following problems occur.

First, each component of the magnetic circuit may or may not have a large magnetic path cross-sectional area due to restrictions such as head size and mass. Given the above configuration, the saturation flux density of the magnetic circuit is uniform. The magnetic saturation becomes severe in the area where the magnetic path cross section is small. Therefore, the efficiency of the entire magnetic circuit is reduced.

Further, the magnetic substance of the magnetic circuit component is required to have a high maximum magnetic permeability, a high saturation magnetic flux density, and a high volume specific resistivity. There is no body, but there are advantages and disadvantages due to the magnetic substance. Therefore, if the characteristics of the entire magnetic circuit are made uniform, one of the characteristics is sacrificed.

Further, in a wire dot head provided with a large number of solenoids, magnetic interference between the solenoids has become a problem as miniaturization has occurred.

These problems are not limited to the above wire dot head, and are common to all impact recording heads that record by hitting a recording medium with the recording member by driving the recording member with a solenoid.

[Means for Solving Problems] According to the present invention in order to solve such problems, an impact recording head for recording by driving a recording member with a solenoid and hitting the recording medium with the recording member. The magnetic circuit for flowing the magnetic flux generated by the coil of the solenoid holds the core of the solenoid, the yoke member that is a holding member of the core, and the striking member that strikes the recording medium, and operates by the magnetic force of the solenoid. A movable member, which is a part of the movable member, and a movable core provided on the movable member. The core and the movable core are provided with a magnetic body having a high saturation magnetic flux density and a magnetic body having a high maximum magnetic permeability, respectively. A structure in which a high magnetic material is provided in a portion where the magnetic flux concentrates immediately after the magnetic flux is excited is adopted.

[Operation] According to such a configuration, the attraction force is further increased at the portion where the magnetic flux is likely to be concentrated at the beginning when the magnetic flux is applied to the solenoid, and the core and the movable core are quickly attracted, and then the magnetic body is magnetically saturated. When approaching, a magnetic material having a high saturation magnetic flux density exerts a higher attraction force. Further, when the excitation of the solenoid is cut off, the holding force of the magnetic material having a high maximum magnetic permeability is small, so that the attraction force is quickly reduced. As a result, the responsiveness when the striking operation for recording is repeated continuously is improved, and high-speed recording becomes possible.

[Embodiment] Hereinafter, details of an embodiment of the present invention will be described with reference to FIGS. 1 to 7. Here, in the structure of the conventional wire dot recording head shown in FIGS. 9 and 10 described above, the head in which the material composition of each component of the magnetic circuit of the solenoid for driving the wire 22 is changed is used as an example. That is, the structure of the head of each embodiment is the same as that of the conventional head except for the point related to the material structure, and the description thereof will be omitted. Also, from FIG.
Each member in FIG. 7 is provided with a reference numeral corresponding to the conventional example.

First Embodiment FIGS. 1 and 2 are a sectional view for explaining the structure of a solenoid peripheral portion of a wire dot recording head according to a first embodiment of the present invention and a view taken along the line BB in FIG. It is a rear view of each corresponding member.

Here, let us consider the flow of the magnetic flux Φ and the cross-sectional area of the magnetic path in the magnetic circuit of the solenoid shown in FIGS.

Due to the magnetomotive force generated by the energization of the coil 7, the magnetic flux Φ flows through the magnetic circuit including the core 6, the plunger 13, the auxiliary yoke 11, and the yoke, as shown by the arrows in both figures.

At this time, for the yoke 5 and the auxiliary yoke 11, as shown in FIG. 2, a magnetic path is secured with a large width between the lines CC '. On the other hand, the core 6 and the plunger 13 are CC ′
The cross-sectional area of the magnetic path is significantly smaller than that of the yoke 5 and the auxiliary yoke 11 because the columnar shape is formed with a diameter significantly smaller than the width between the lines. In particular, the cross-sectional area of the magnetic path of the plunger 13 is the smallest in all magnetic paths.

Therefore, in this embodiment, the plunger 13 and the core 6 are formed of a 50% cobalt-iron alloy containing 50% cobalt as a magnetic material having a particularly high saturation magnetic flux density. The yoke 5 and the auxiliary yoke 11 are made of 3% silicon steel containing 3% silicon as a magnetic material having a high maximum magnetic permeability and a high volume specific resistivity although the saturation magnetic flux density is not so high.

With this structure, magnetic saturation can be prevented in the plunger 13 or the core 6 where the cross-sectional area of the magnetic path is small.
A high magnetic force can be obtained for the applied power, efficiency is improved, and power consumption can be reduced or recording can be speeded up. Further, since the cross-sectional area of the plunger 13 or the core 6 is small, the size and weight of the entire head can be reduced.

Second Embodiment Next, FIG. 3 shows a structure of a solenoid peripheral portion according to a second embodiment of the present invention.

In this embodiment, the portions of the plunger 13 and the core 6 indicated by reference numerals 13a and 6a and the portions indicated by reference numerals 13b and 6b are made of magnetic materials having different characteristics. That is, the portions 13a and 6a closer to the base end side, which are swinging fulcrums of the armature 14, are formed of 3% silicon steel having high maximum magnetic permeability and volume specific resistivity, and the portions closer to the tip (free end) side of the armature 14 are formed. 13
b and 6b shall be formed from 50% cobalt-iron alloy with high saturation magnetic flux density and low maximum permeability.

When a magnetic flux is applied to this magnetic circuit, an attraction force acts between the core 6 and the plunger 13 and the armature 14 swings. At that time, the air gap between the core 6 and the plunger 13 remains until the armature 14 starts moving. Since the space between the fulcrum-side portions 6a and 13a of 14 is narrower than the space between the portions 6b and 13b, the magnetic flux concentrates in the regions on the side of the portions 6a and 13a.

In the present embodiment, since the portions 6a and 13a where the magnetic flux is concentrated at the beginning of the flow of the magnetic flux are made of a magnetic material having a high maximum magnetic permeability, the concentration of the magnetic flux is further increased, and the suction acting at the beginning is increased. The power becomes greater. Further, the core 6 and the portions 6b and 13b of the plunger 13 work to compensate for the magnetic saturation of the portions 6a and 13a, and at that time, the armature 14 has a narrow air gap between the portions 6b and 13b while swinging. Therefore, a sufficient suction force can be obtained.

Also, when the solenoid is de-energized, 3% silicon steel has a high volume specific resistivity and a small coercive force, so the attraction force quickly decreases, and the operation of the armature 14 becomes a disadvantageous braking force. Also few.

As described above, according to the present embodiment, a large attractive force is immediately obtained from the beginning of the flow of the magnetic flux, the attractive force is immediately reduced when the excitation is cut off, and the braking force due to the residual magnetism is small, so that the armature 14 can be driven at high speed, The recording speed can be increased.

Third Embodiment Next, FIGS. 4 and 5 show a structure according to a third embodiment of the present invention.

In this embodiment, in the auxiliary yoke 11 facing the armature 14, the inner peripheral side portion 11b of the circular surface facing the armature 14 is formed of 50% cobalt-iron alloy, and the remaining portion 1b is formed.
1a shall be formed from 3% silicon steel.

The armature 7 is also a magnetic body, and a suction force acts between it and the auxiliary yoke 11. In this embodiment, the portion 11a that occupies almost the entire auxiliary yoke 11 is made of 3% silicon steel having a high maximum magnetic permeability, a high volume specific resistivity and a small coercive force, so that the auxiliary yoke 11 can attract the armature 7. The magnetic flux can be strengthened from the beginning, and when the excitation is turned off, the attractive force disappears quickly. Further, by setting the thickness of the portion 11b made of a cobalt-iron alloy having a high saturation magnetic flux density to be saturated similarly with the magnetic flux density at which the armature 14 is magnetically saturated, it is possible to prevent the auxiliary yoke 11 from being magnetically saturated first, A strong attractive force can be maintained during excitation.

Therefore, also in the case of this embodiment, the armature 14 can be driven at a high speed, and the recording speed can be increased.

Fourth Embodiment Next, FIG. 6 shows a structure according to a fourth embodiment of the present invention.

In this embodiment, in the armature 14, a portion 14a on the tip side (free end side) of the plunger 13 is made of a lightweight and high-strength metal, and the remaining base-side portion 14b is high-strength, high saturation magnetic flux density 50% cobalt. -It shall be formed from an iron alloy.

When the magnetic flux flows in this magnetic circuit, the magnetic flux Φ flowing from the auxiliary yoke 11 directly to the plunger 13 as shown by the arrow.
₁ and a magnetic flux Φ ₂ flowing from the auxiliary yoke 11 through the armature 14 to the plunger 13. Since the gap between the auxiliary yoke 11 and the armature 14 is narrower than the gap between the auxiliary yoke 11 and the plunger 13 and the facing area is large, the magnetic flux Φ ₂ is large at the initial excitation of the solenoid, and the attraction between the auxiliary yoke 11 and the armature 14 is large. Power is also great. Here, the magnetic path cross-sectional area of the armature 14 is small, but the part where the magnetic flux Φ ₂ flows.
By forming 14b from a cobalt-iron alloy having a high saturation magnetic flux density, the armature 14 is less likely to be magnetically saturated and a high attractive force is obtained. Therefore, the power consumption can be reduced or the recording speed can be increased.

Fifth Embodiment Next, FIG. 7 illustrates a structure according to a fifth embodiment of the present invention.

In the present embodiment, in the auxiliary yoke 11 shown in the same drawing, a portion 11a of a region facing each armature 14, that is, a region facing each solenoid is made of 3% silicon steel, and is provided in a space between adjacent armatures 14. The portion 11b of the opposing region is formed of 50% cobalt-iron alloy.

According to such a structure, when one solenoid is excited, the maximum magnetic permeability of the portion 11b of 50% cobalt-iron alloy is low, so the magnetic flux Φ is silicon steel having a high maximum magnetic permeability as shown by the arrow in FIG. Since it flows concentratedly in the portion 11a consisting of, and does not spread, magnetic interference with adjacent solenoids can be suppressed, and high-speed stability of the actuator can be improved.

It should be noted that when the portion 11a is magnetically saturated, the magnetic flux Φ also flows in the portion 11b to prevent the magnetic characteristics of the magnetic path from being extremely deteriorated, but since the amount is small, the magnetic interference due to this is small and the high-speed stability of the actuator is improved. It does not hurt.

In addition, the yoke 5 has the same structure,
The effect of suppressing magnetic interference can be further enhanced.

Although the first to fifth embodiments have been described above, it goes without saying that the structures of these embodiments are appropriately combined. Further, other magnetic materials may be used instead of the above-mentioned silicon steel and cobalt-iron alloy.

Also, the structure of the magnetic circuit of the solenoid as described above is not limited to the wire dot head of the suction type solenoid structure, and is also applied to the solenoids of other impact recording heads such as the spring charge type wire dot head and the daisy wheel recording head. The effect of can be expected.

[Effects of the Invention] As is apparent from the above description, according to the present invention, an impact recording head that performs recording by driving a recording member with a solenoid to strike a recording medium with the recording member, A magnetic circuit for flowing a magnetic flux generated by a coil of a solenoid is a movable member that is a portion that holds the core of the solenoid, a yoke member that is a holding member of the core, and a striking member that strikes a recording medium and that is operated by the magnetic force of the solenoid. , And a movable core provided on the movable member, wherein the core and the movable core respectively include a magnetic body having a high saturation magnetic flux density and a magnetic body having a high maximum magnetic permeability, and the magnetic body having a high maximum magnetic permeability is Since it is provided in the part where the magnetic flux concentrates immediately after the magnetic flux is excited, it is easier to concentrate in the part where the magnetic flux concentrates at the beginning when the magnetic flux is applied to the solenoid. By increasing the attractive force and quickly attracting the core and the movable core, when this magnetic body approaches magnetic saturation, the magnetic body having a high saturation magnetic flux density exerts a higher attractive force,
Further, when the excitation of the solenoid is cut off, the holding force of the magnetic material having a high maximum magnetic permeability is small, so that the attraction force is quickly reduced. As a result, there is an excellent effect that the responsiveness when the striking operation for recording is repeated continuously is excellent and high-speed recording becomes possible.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a solenoid peripheral portion of a wire dot recording head according to a first embodiment of the present invention, FIG. 2 is a rear view of the main portion of the head, and FIG. 3 is a head according to the second embodiment. 4 is a sectional view of the solenoid peripheral portion of FIG. 4, FIG. 4 is a sectional view of the solenoid peripheral portion according to the third embodiment, FIG. 5 is a rear view of the main portion of the same embodiment, and FIG. 6 is a solenoid peripheral portion according to the fourth embodiment. FIG. 7, FIG. 7 is a rear view of an essential part according to the fifth embodiment, FIG. 8 is an explanatory view of dot matrix recording, and FIGS. 9 and 10 are sectional views showing the structure of a conventional wire dot recording head, respectively. It is a figure and an exploded perspective view. 5 …… Yoke, 6 …… Core 7 …… Coil, 10 …… Return spring 11 …… Auxiliary yoke, 13 …… Plunger 14 …… Armorature, 22 …… Wire

Claims (2)

[Claims] 1. An impact recording head for recording by driving a recording member with a solenoid to strike a recording medium with the recording member, wherein a magnetic circuit for flowing a magnetic flux generated by a coil of the solenoid is the solenoid. Core, a yoke member that is a holding member of the core, a movable member that is a portion that holds a striking member that strikes a recording medium and that is operated by the magnetic force of the solenoid, and a movable core that is provided in the movable member. And the movable core are each provided with a magnetic body having a high saturation magnetic flux density and a magnetic body having a high maximum magnetic permeability, and the magnetic body having a high maximum magnetic permeability is provided in a portion where the magnetic flux concentrates immediately after the magnetic flux excitation. Impact recording head featuring. 2. The impact recording head according to claim 1, wherein a portion where the magnetic flux concentrates immediately after the magnetic flux excitation is provided on the fixed end side of the movable member of the core and the movable core.