JPS5952667A - Spring charge system printing head - Google Patents

Abstract

PURPOSE:To make the titled printing head compact while facilitating the assembling thereof and to make it possible to reduce the generation frequency of an obstacle or a bad condition, in a wire dot printer, by providing such a structure that a magnetic circuit is separated from a spring. CONSTITUTION:When a current is not supplied to a coil 6, the magnetic flux of a permanent magnet 6 is concentrated to a circuit consisting of a yoke 2, a core 4, an armature 17 and a yoke 10 and the armature 17 is attracted to the core 4 to be brought to a non-printing position. When a current is supplied to the coil 16, the magnetic flux passing through the core 4 is contradicted and the end part of the armature 17 is pushed up by a coil spring 15 while printing operation is performed by a wire 18 and the armature 17 is returned to the non-printing position after the supply of a current is finished. As mentioned above, because a spring plate is not interposed in the magnetic circuit, magnetic resistance can be made low, a printing head becomes small, the welding work of the spring plate and the yoke is eliminated, the generation of an obstacle or a bad condition caused by welding is prevented and the number of assembling works can be reduced.

Description

[Detailed description of the invention] The present invention relates to a spring-charged printhead.

A conventional spring charge type print head used in a dot impact type printer has the advantage that it has a simpler structure and can print at higher speeds than other types of print heads.

FIG. 1 is a perspective view of a conventional spring charge type print head. As shown in the partial cross section of the figure, a ferromagnetic metal yoke 10 is fixed to the upper surface of the cylindrical permanent magnet 8, and the ends of a plurality of fan-shaped spring plates 14 are attached to the upper surface of the yoke 10, respectively. It is fixed in place. Furthermore, a yoke 12 made of ferromagnetic metal is fixed to the upper part. A bottomed cylindrical yoke 2 made of ferromagnetic metal is fixed to the lower surface of the permanent magnet 8. The upper ends of the plurality of cores 4 integrally provided at the bottom of the yoke 2 are connected to armatures 16 made of ferromagnetic metal fixed to the upper surface of each spring plate 14.
A predetermined distance is maintained between the lower surface of the spring plate 14 and the lower surface of the spring plate 14, respectively.

A wire 18 for printing dots is attached to the tip of each armature 16. A coil 6 is attached around each core 4. Each spring plate 14, an armature 16 and a wire 18 fixed thereto
and the core 4 and coil 6 below it are each 1
A unit for printing two dots is constructed. In each printing unit, the magnetic flux generated from the permanent magnet 8 is
York 2. Core 4. Armature 16 and yoke 1
0 and 12 are concentrated within the magnetic circuit.

When no current is supplied to the coil 6, the armature 16 is attracted to the core 4 by the magnetic flux passing through this magnetic circuit, and the spring plate 14 is bent accordingly and attracted to the core 4, so that it is in the non-printing position. . When printing, core 4
A current is supplied to the coil 6 in a direction that cancels the magnetic flux passing through the coil 6.

In response to this, the suction force that had been acting on the armature 16 disappears, so the spring plate 14, which had been bent (7), is tightened back to its original state, and the wire 18 moves accordingly, causing the 'C printing operation. At the end of the printing operation, the coil 6
By stopping the current supply to the spring 14, the spring @14 is bent again and tightened to the non-printing position.

In the conventional spring charge type print head as described above, problems such as the spring plate 14 breaking during operation and uneven shading of printed dots are likely to occur.
Furthermore, it requires a large number of man-hours during manufacturing. That is, although the armature 16 is welded and fixed to the spring plate 14, the welded portion is hardened after the welding process and is likely to break during the printing operation. Furthermore, since the degree of hardening differs for each spring plate 14, the magnitude of elastic stress during printing operation also differs for each spring plate, resulting in uneven shading for each printed dot. Further, during manufacturing, the steps of welding the armature 16 to the spring plate 14, attaching the end of the spring plate 14 between the yokes 10 and 12, and screwing or welding are required, which requires a large amount of assembly man-hours.

In addition, in the above-mentioned magnetic circuit, if there is variation in the size of the gap between the armature 16 and the yoke 12, the magnetic resistance of the gap will fluctuate, causing uneven shading of printed dots. It is necessary to match it with high precision, which increases the number of manufacturing steps.

In order to improve the problem that the spring plate 14 breaks among the above problems, the spring plate 14 and the armature 16 are
There is a short IJ charge type print head that is made of a ferromagnetic material by integrating the two. In this case, if the elastic stress at the location where the spring plate 14 acts is set to a predetermined value, the plate thickness will become thinner, and in order to reduce the magnetic resistance at that location and obtain efficient operation, the width should be increased. The cross-sectional area cannot be made thicker, and the dimensions of each printing unit become larger.

As explained above, conventional spring-charged print heads are prone to problems such as spring breakage.
This method requires a large amount of manufacturing man-hours and has the drawbacks of being large in size.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, to provide a small spring-charge type print head that requires less man-hours to manufacture than the conventional print head, does not cause problems such as spring breakage, and is compact.

The printing of the first invention in the present invention - Rad is a permanent magnet, first and second yokes of ferromagnetic material connected to the permanent magnet, and a magnetic core connected to the second yoke. The attached coil, the first guide part side which is provided with a guide hole and equipped with a coil spring that engages with the guide hole and is elastically deformed, and the other side which has a printing wire attached to one end. The end portion is attracted to the permanent magnet via the first yoke, a first predetermined location is placed at a position where the magnetic flux generated from the magnetic core passes, and a second predetermined location is pressed by the coil spring. The apparatus includes at least one printing unit having a ferromagnetic armature disposed at a position and a second guide member for positioning the periphery of the armature.

The print head of the second invention is such that the first guide member of the print unit in the print head of the first invention is provided with an adjusting means for adjusting the elastic force of the spring coil.

The print head of the third aspect of the present invention is the print head of the first aspect, in which a cap of a predetermined shape is interposed at the location where the coil spring presses the armature.

The print head of the fourth invention is one in which an elastic support section is provided to support the end of the armature that is attracted to the permanent magnet in the print unit of the print head of the first invention.

Next, the present invention will be described in detail with reference to the drawings.

FIG. 2 is a perspective view showing a first embodiment of the invention. As shown in the partial cross-section of the figure, magnetic metal yokes 10 and 2 are fixed to the upper and lower surfaces of a cylindrical permanent magnet 8, respectively, and a plurality of cores 4 are provided at the bottom of the yoke 2. It's been a long time. Further, a cylindrical plastic spring guide 5 is fixed to the center of the bottom of the yoke 2.

A plastic armature guide 2o is fixed to a predetermined location on the upper surface of the yoke 10, and the spring guide 5 is integrally formed with an armature guide 22 that projects from the upper surface.

The armature 17 is a magnetic metal rod having one end protruding on both sides, and a wire 18 for printing dots is attached to the other end. Armature guide 2o and 22 pieces, yoke 10. A number of spaces are formed on the upper surface of the core 4 and the spring guide 5 for arranging the armature 17, and when the armature 17 is placed in each space, it is attracted by the magnetic flux generated by the permanent magnet 8, and a protrusion is provided. The end portion is attached to the yoke 10, and the center portion is attached to the core 4. The end of the armature 17 on the side where the wire 18 is attached covers the mouth of a hole provided in the spring guide 5. A coil spring 15 is inserted and mounted in advance into this hole, and presses the armature 17 from below. Each armature 17 has a wire 1 attached to it.
8, the core 4 below it, the coil 6 disposed around it, and the coil spring 15 in the hole of the spring guide 5, each constitute a printing unit for printing one dot.

The print head configured as described above is housed in the case 1, and the plurality of wires 18 coming out of the case 1 through holes provided on the top surface of the case 1 are guided to a predetermined position by a wire guide (not shown). Performs printing operation to the position.

FIGS. 3(a) and 3(b) are partial sectional views for explaining the operation of the printing unit in the print head shown in FIG. 2. FIGS. FIG. 5A shows a case where no current is supplied to the coil 6. In this case, the magnetic flux generated from the permanent magnet 8 is transmitted to the yoke 2. Core 4. The armachier 17 is concentrated in the magnetic circuit consisting of the armachier 17 and the yoke 10, and is attracted to the core 4 and is in the non-printing position. Same figure (
b) shows the case where current is supplied to the coil 6. In this case, a current is supplied to the coil 6 in a direction that cancels the magnetic flux passing through the core 4. Correspondingly from core 4 to armature 1
Since the suction force acting on the coil spring 15 disappears, the end of the armature 17 is pushed up by the elastic force of the coil spring 15, and the protruding stopper 24 provided inside the case l is pushed up.
Accordingly, the wire 18 performs a printing operation. At the end of the printing operation, by stopping the current supply to the coil 6, the armature 17 is attracted to the scoop core 4 and returns to the non-printing position, that is, the position shown in FIG.

In this embodiment, unlike conventional print heads, a spring plate is not interposed in the magnetic circuit of the print unit, and the armature 17 directly contacts the yoke 2 and the core 4 to form the magnetic circuit. It is easy to reduce the reluctance of the magnetic circuit below the required limit by reducing the dimensions of the components. Furthermore, conventional assembly processes such as welding the spring plate to the armature and welding (or screwing) the spring plate to the yoke are no longer necessary, which eliminates failures during operation due to localized hardening of the spring plate during welding. This also eliminates the occurrence of problems.

FIG. 4 is a partial sectional view showing a second embodiment of the present invention. In the print head shown in the figure, the yoke 2 is
and a hole 26 passing through the spring 25.
A thread is provided at a predetermined location of the threaded rod 27 from below.
By screwing in the coil spring 15, the elastic stress of the coil spring 15 can be adjusted. By adjusting the position of the threaded rod 27 using a screwdriver, the printing strength of the wire 18 can be adjusted, so there is an advantage that the shading of printed dots can be adjusted for each printing unit.

FIG. 5 is a top view showing a third embodiment of the present invention. As shown in the partially broken part of the same figure, a guide 28 is used in which the armature guides 20 and 22 and the spring guide 5 in FIG. 2 are all integrated, and the armature 1
Coil spring 15 (
A hole 30 is provided for inserting a (not shown).

The use of an integrated guide 28 reduces print head manufacturing time.

FIG. 6 is a partial perspective view showing a fourth embodiment of the present invention. A rubber stopper 34 is provided between the case 1 and the outer side of the armature 17 arranged in a predetermined space of an integrated guide 320 similar to the guide 28 in FIG. The stopper 34 is connected to the yoke 10 and the case 1.
The armature 17 contacts the side of the armature 17 and supports it, so that the armature 17 moves along the dashed arrow A during printing operation.
Prevent it from shifting in the direction of. Since the stopper 34 is elastically deformed in accordance with the movement of the armature 17, it prevents the armature 17 from shifting without interfering with the printing operation.

FIG. 7 is a partial sectional view showing a fifth embodiment of the present invention. In the figure, at the end where the coil spring 15 presses the armature 17, there are several caps 36 whose outer peripheries slide along the holes of the spring guides 5.

When the coil spring 15 directly presses the armature 17 as shown in FIG.
In order to prevent variations in the position and direction in which the coil spring 17 presses the armature 17, resulting in variations in print density, the end of the coil spring 15 must be formed into a predetermined shape and size. It requires a lot of manufacturing man-hours. As shown in this figure, by attaching a short cylindrical cap 36 to the end of the coil spring 15, the position and direction in which the coil spring 15 presses the armature 17 can be prevented from changing more easily than when pressing directly. Uniform printing strength can be obtained.

FIGS. 8(a) to 8(e) are side views showing other examples of forming the cap 36 in FIG. 7. The same figure (a
The cylindrical cap shown in ) has a hollow portion into which the end of the coil spring 15 is fitted, thereby preventing the end of the coil spring 15 from shifting laterally during operation.

The cap shown in FIG. 6(b) has a protrusion at the bottom of a short cylinder and is fitted into the end of the coil spring 15, thereby preventing the end of the coil spring 7' IJ ring 15 from shifting laterally during operation.

The caps shown in Figures (C) and (d) both have hemispherical tops and press the armature 17 through point contact during operation, so that fluctuations in the position and direction of suppression can be further reduced. The spherical cap shown in FIG. 3(e) does not change its shape depending on its orientation, so it operates smoothly without getting caught on the peripheral wall of the hole of the spring guide 15, and is easy to manufacture.

As is clear from the above description, one aspect of the present invention is to provide a spring that is smaller than conventional ones, easier to assemble, and less prone to failures and malfunctions by having a structure in which the magnetic circuit and the spring are separated. This has the effect of realizing a charge-type print head, and the effect is particularly significant when applied to a case where a large number of print units are accommodated.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional spring-charge type print head, and FIGS. 4 is a partial sectional view showing a second embodiment of the invention, FIG. 5 is a top view showing a third embodiment of the invention, and FIG. 6 is a partial perspective view showing a fourth embodiment of the invention. 7 and 8(a) to 8(e) are a partial sectional view and a side view, respectively, showing a fifth embodiment of the present invention. 1... Case, 2, 10.21... Yoke, 4°°°°° core, 5.25... Tin ring guide, 6...・Coil, 8...
Permanent magnet, 15... Coil spring, 17.
... Armature, 18.1.11. wire, 2
0.22... Armature guide, 24...
... Stopper, 27 ... Threaded rod, 28.32
・・・・・・Guide, 34°゛°°゛Stopper, 36・
····cap. Tube / Atsushi Kasumi Figure 2 (1:l) (1)) fV, 3
Diagram 4 z 5 Approximately 7 Diagram (θ) Cb) Cc) (σ
)Ce)

Claims (8)

[Claims] (1) A permanent magnet and a strong (°C) connected to the permanent magnet.
A first and second yoke made of a rigid body, a coil attached to a 92L4e magnetic core on the second yoke, and a coil spring that is provided with a guide hole and is elastically deformed by engaging with the guide hole. A printing wire is attached to one end of the first guide member, and the other end is iron-tight to the permanent magnet via the first yoke, and the printing wire is attached to a first predetermined location. is placed in a position where the magnetic flux generated from the magnetic core passes, and a second B is a ferromagnetic armature that is placed in a position where a predetermined portion is pressed by the coil spring, and a peripheral portion of the armature is positioned. 1. A spring-charge type print head comprising at least one print unit having a second guide member for controlling the print head. (2) A spring charge type print head according to claim (1), wherein the first and second guide members are integrally formed. (3) A permanent magnet, first and second yokes made of ferromagnetic material connected to the permanent magnet, a coil attached to a magnetic core connected to the second yoke, and a guide hole provided. A first guide S is provided with a coil spring that engages with the guide hole and is elastically deformed, and is provided with an adjusting means for adjusting the elastic force of the coil spring, and a printing wire is attached to one end of the first guide. The other end is attracted to the permanent magnet via the first yoke, the first predetermined location is located at a position where the magnetic flux generated from the magnetic core passes, and the second predetermined location is located at the location where the magnetic flux generated from the magnetic core passes. a ferromagnetic armature placed in a position to be pressed by a coil spring;
and a second guide member for positioning a peripheral portion of the armature. (4) The spring charge type print head according to claim (3), wherein the first and second guide portion sides are entirely integrally formed. (5) A permanent magnet, first and second yokes made of ferromagnetic material connected to the permanent magnet, a coil attached to a magnetic core connected to the second yoke, and a guide hole are provided. A first guide part is equipped with a coil spring that engages with the guide hole and is elastically deformed, and a printing wire is attached to one end of the guide part and the other end is connected through the first LD yoke. The first predetermined portion is attracted by the permanent magnet and placed at an appropriate position to absorb the magnetic flux generated from the magnetic core.
a ferromagnetic armature arranged in a position where a predetermined portion of the cloth 2 is pressed by an elastic force transmitted through a cap of a predetermined shape provided at the end of the coil spring; A spring-charge type print head characterized by comprising at least one printing unit having a second guide member for positioning the peripheral portion. (6) The spring charge type print head according to claim (5), wherein the first and second guide portions are all integrally formed. (7) A permanent magnet, first and second yokes made of ferromagnetic material connected to the permanent magnet, a coil attached to a magnetic core connected to the second yoke, and a guide hole provided. A first guide member is equipped with a coil spring that engages with the guide hole and is elastically deformed, and a printing wire is attached to one end of the guide member, and the other end is connected to the first guide member through the first yoke. a ferromagnetic armature that is attracted to a permanent magnet, has a first predetermined portion disposed at a position through which the magnetic flux generated from the magnetic core passes, and has a second predetermined portion disposed at a position pressed by the coil spring; At least one printing unit includes a second guide portion side for positioning the peripheral portion of the armature, and an elastic support member that contacts and supports the end portion of the armature that is attracted to the permanent magnet. A spring-charged print head featuring two features. (8) The spring charge type print head according to claim (7), wherein the first and second guide portion sides are all integrally formed.