JPS61135760A - Printing head of wire dot printer - Google Patents

Abstract

PURPOSE:To uniformize the printing characteristics of a plurality of printing wires, by forming an armature in integral relation to the arm like spring part for supporting the armature. CONSTITUTION:A base part 27, a spring part 28 and an armature part 29 are integrally formed in a support part 25 from one material 30 and the leading end of the armature part 29 is inserted between two bent parts 32, 33 in a movable part 24 and spot welding is performed in this state so as to hold two bent parts 32, 33 between electrodes to weld the armature part 29 and the bent part 32. Because the movable part 24 is formed in a printing head 36 as mentioned above, the spring part 28 and the armature part 29 in the support part 25 are easily formed with dimensional accuracy extremely reduced in irregularity and, because the gap between adjacent armature parts 29 is wider than that in the case of a printing head 22, the welding work of the armature part 29 and a lever 26 is easy.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention involves fixing a printing wire to each free end of a plurality of elastic cantilever beams, each of which has one end fixed. A wire dot printer which is bent by magnetic flux from a permanent magnet, and when printing, the magnetic flux is extinguished by a solenoid to repel a cantilever beam, and the printing wire is used to print dots by the repulsive force of the cantilever beam. The present invention relates to printheads, particularly configurations that are easy to manufacture.

[Prior art and its problems]

In a wire dot printer, a print head equipped with 7 to 24 printing wires and a drive mechanism for these is usually run, for example, through an ink ribbon, facing the paper surface, and at the same time as this running, the printing wires are It is selectively driven to print dot patterns such as letters on the paper surface. Figure 7 is a vertical cross-sectional view of such a conventional print head, and Figure 8 shows the main parts in Figure 7. P arrow view and FIG. 9 are XX sectional views in FIG. 8. In FIGS. 7 to 9, 1 is an annular base made of an elastic ferromagnetic material, and 2 is a predetermined ring-shaped base formed such that one end is fixed to the inner edge of the base 1 and the other end is directed toward the center of the base 1. The number of arm-like spring parts is equal to the number of printed dots, and the base part 1 and the spring part 2 are integrally formed from one temporary piece. Reference numeral 3 designates a leaf spring consisting of the base 1 and the spring portion 2 formed in this manner.

4, with one end facing the center of the base 1, and the other end facing b
A r-f-near made of ferromagnetic material in the shape of a rectangular prism, welded and fixed to the tip of the spring part 2 at two welding points shown by 5.
is a printing wire with one end protruding from the surface on which the armature 4 of the leaf spring 3 is attached, and the other end is brazed to the tip of the armature 4, and 6 is the above-mentioned leaf spring 3, armature 4, and printing wire 5. It is a movable part consisting of.

7 and 8 are formed with equal outer diameter and inner diameter, respectively.
Both are annular magnetic path members and permanent magnets made of ferromagnetic material, and their outer and inner diameters are approximately equal to the outer and inner diameters of the base l of the leaf spring 3, respectively. 9
, 10 are annular plate-shaped ferromagnetic material bases and yokes whose outer diameters are approximately equal to the outer diameters of the permanent magnets 8. It is formed widely, and the permanent magnet 8 is magnetized in the axial direction of the ring.

In FIG. 7, a permanent magnet 8, a magnetic path member 7, a movable part 6, and a yoke 10 are sequentially stacked on a base 9, and these are connected to a funnel-shaped cover 11 having a 7-lunge 12 at its large end.
The main part is configured such that it is tightened and fixed between the flange 12 and the base 9 by screws 13, and the tip of the printing wire 5 passes through the cover 11 and protrudes from the small end of the funnel. . Reference numerals 14 and 15 denote an intermediate wire guide and a tip wire guide, which are provided at the intermediate and small ends of the cover 11 and guide the printing wire 5. With the movable part 6 fixed between the yoke 10 and the magnetic path material 7 as described above, the end surface of the armature 4 on the leaf spring 3 side faces the inner surface of the yoke 10 with the gap 16 interposed therebetween. ,
Each part is configured. Reference numeral 17 indicates a cylindrical iron core with one end facing the armature 4 through a gap 18 and the other end contacting and fixed to the base 9. Reference numeral 19 indicates a coil wound around the iron core 17. is connected to a lead wire 21 extending through a cylindrical insulator 20 that is fitted inside the base 9 and fixed with adhesive. 22 is a print head consisting of the above-mentioned parts.

In the print head 22, when no printing operation is performed, the coil 19 is not energized, and at this time the armature 4 is
Air gap 18, iron core 17, base 9, permanent magnet 8, magnetic path material 7
, the base 1 of the movable part 6, the yoke 10. The printing wire 5 is attracted to the iron core 17 by the magnetic flux φ caused by the permanent magnet 8 passing through the closed magnetic path 23 consisting of the air gap 16 and the armature 4, and therefore the printing wire 5 remains stationary at the standby position. That is, at this time, the spring portion 2 of the leaf spring 3 is in a deflected state. When the magnetic flux Φm is passed through the coil 19 in the print head 22, the magnetic flux ΦC generated by the coil cancels out the magnetic flux Φm, so the force that attracts the armature 4 to the iron core 17 disappears, and the armature 4 becomes a spring part. As a result, the tip 5a of the printing wire 5 is further projected from the cover 11. Therefore, printing wire 5
For example, when the tip 5a of the ink ribbon is opposed to the paper via the ink ribbon, the tip 5a collides with the ink ribbon and a dot is printed on the paper. At the time when the printing wire 5 collides with the ink ribbon, the current in the coil 19 has already been extinguished, so the armature 4 absorbs the bounce when the printing wire 5 collides with the object to be printed and the magnetic flux Φ based on the permanent magnet 8. Due to the attraction force caused by the coil, the coil 19 returns to the state when it is not energized.

Since the print head 22 prints phrases as described above, the plurality of printing wires 5 must have uniform printing characteristics such as printing force and printing speed, and for this purpose, the movable part 3 is configured. The dimensions of the spring portion 2, armature 4, and printing wire 5, as well as the finished dimensions when these members are assembled, must be formed uniformly with high accuracy for the plurality of printing wires 5. For this reason, for example, the armature 4 and the spring part 2 must be welded in a precise relative position at the correct welding point.
[Me] If the number of printed dots is small and the number of printed dots is 24, the spacing between adjacent armatures 4 will be 0.3.
(+m), it is extremely difficult to perform such welding work manually even if a jig is used. Therefore, if you try to automate this welding work, it will be difficult to perform welding work by hand even if you use a jig. Supply, alignment conveyance, positioning, gripping,
There is a problem in that the movable part 3 cannot be manufactured economically because it requires a mechanism to perform a series of operations such as welding and taking out the assembled product. In addition, in the print head 22, the armature 4 is welded to the spring part 2 at point b, so when no printing operation is performed, the armature 4 and the spring part 2 are in the state shown by the dotted line in FIG. As a result, a gap is created between the part a of the bottom surface of the armature 4 on the side of the spring part 2 and the spring part 2, and the effective length l of the spring part 2 becomes longer than 11 until the spot welding position. If the precision of the position of the welding point is low, the spring constant of the spring part 2 will be proportional to 1/(l"), so the print head 22, to which the armature 4 and the spring part 2 are fixed, has a There is a problem in that the printing force of No. 5 tends to vary widely, and furthermore, the print head 22 has a thin plate thickness of about 0.3 to Q. It is easy to deform into a concave shape, and when such a concave portion is formed, the elasticity of the spring portion 2 becomes unstable, resulting in a problem that the printing characteristics of the printing wire 5 become non-uniform.

That is, in the above-mentioned print head 22, although it is easy to manufacture each part constituting the movable part 3, it is difficult to assemble these parts. There is a problem in that it is difficult to achieve uniform printing characteristics such as printing power and printing speed. For this reason, a print head has already been proposed in which a movable part 6 having a uniform printing force is obtained by integrally forming - number of leaf springs 3 and a plurality of armatures 4 from a single material. However, in such a print head, although the distance between adjacent armatures is as narrow as Q,3 (xi) as described above, the thickness of the armature is is as thick as 1°2 to 1.5 [dragon], so there is a problem that it is difficult to integrally mold the leaf spring 3 and the armature 4 by press working with high productivity, and the adjacent armature There is a problem in that it is extremely difficult to braze the printing wire 5 to the tip of the armature 4 due to the narrow spacing between the two.

[Purpose of the invention]

An object of the present invention is to provide a print head for a wire dot printer that can be easily manufactured so that the printing characteristics of each of a plurality of printing wires are uniform by solving the above-mentioned problems with the conventional print head. purpose.

[Key points of the invention]

In order to achieve the above-mentioned object, the present invention provides a print head for a wire dot printer in which a print wire is driven and one end of the print wire prints dots, and the other end of the print wire is fixed to the tip of a lever. , the lever is fixed at its base to an armature that forms part of a closed magnetic path and is driven by the magnetic flux in this closed magnetic path, and this armature is integrally formed with an arm-like spring portion that supports the armature. By configuring as described above, it is possible to obtain a print head in which it is easy to form a column so that each print characteristic of a plurality of print wires is uniform.

- [Embodiment of the Invention] Fig. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, Fig. 2 is a perspective view of the main part of the movable part 24 in Fig. 1, and Figs. Support part 25 and lever 26 in the figure
It is a manufacturing process explanatory diagram.

In Figures g1 to 4, the movable part 24 has the same function as the movable part 6 in Figure t47, and the support part 25
, a lever 26 and a printing wire 5. The support part 25 is made up of an annular plate-shaped base part 27, an arm-shaped spring part 28, and an armature part 29, which correspond to the base part 1, spring part 2, and armature 4 shown in FIG. The support section 25 is made by turning a disc-shaped material 30 made of an elastomagnetic material having - elasticity, for example, a material such as SK5, into the cross-sectional shape shown in FIG. 3 (to). The thus-processed material is further subjected to wire-cut electrical discharge machining and press working to form a dot equal to the number of printed dots from the base 27 toward the center of the base, as shown in FIG. 3 (q). A number of spring parts 28 are protruded, and an armature part 29 is automatically formed at the tips of these spring parts 28.

That is, in the support portion 25, the base portion 27, the spring portion 28, and the armature 29 are integrally formed from a single material 30. 31 is a through hole provided in the base 27 so that the screw 13 is inserted therethrough.

The lever 26 is made by pressing a plate-like material into the shape shown in Figure 4 (5), and by bending the protrusion formed at the end of the plate material as shown in Figure M4 (B). In the movable part 24, the tip of the armature part 29 is inserted between the two bent parts 32, 32 formed in this way. Spot blast welding is performed by sandwiching the two bent portions 32.degree. 32 between the electrodes, and the armature portion 29 and the bent portion 32 are welded. In this case, the lever 26 is mounted so that its plate surface is parallel to the plane in which the armature portion 29 moves. 33 is a through hole provided to make the lever 26 lighter. Before the lever 26 is attached to the armchair part 29, as shown in FIGS. The printing wire 5 thus brazed is inserted into the intermediate wire guide 14 and the tip wire guide 15 and welded to the armchair portion 29.

2 and 34 in FIG. 1, the armchair portion 29 is connected to the iron core 17.
In other words, the armature portion 29
The position of the damper is adjusted by an adjustment screw 35 so that the tip of the lever 26 to which the printing wire 5 is attached is almost in contact with the damper 34 when the printing wire 5 is not performing a printing operation. 36 is a print head made up of the above-mentioned parts. Printing head 36
Since the is configured as described above, the printing operation is performed in the same manner as in the printing head 22 shown in FIG. When the flow of the coil 19 is cut off and the armchair section returns to the standby position, the energy of the return movement of the movable section 24 is absorbed by the damper as the tip of the lever 26 collides with the damper 34. . Therefore, if the damper 34 is not provided, bouncing of high-order vibrations caused by the armature part colliding with the iron core 17 during the return operation of the armature part 29 is unlikely to occur, and therefore the print head 36 is There is almost no chance of printing errors due to bouncing. Furthermore, since the movable part 24 in the printing pad 36 is formed as described above, the spring part 28 in the support part 25
It is easy to form both the armature section 29 and the armature section 29 with very small dimensional accuracy, and in this case, since the spacing between adjacent armature sections 29 is wider than that of the print head 22, the armature section 29 and Welding work with the lever 26 is easy. Therefore, the print head 36 having such a configuration is a print head that can be easily manufactured so that the print characteristics of the plurality of print wires 5 are uniform.

FIG. 5 is a perspective view of a main part of a movable part 37 in a second embodiment of the present invention. In this case, a lever 38 to which one end of the printing wire 5 is brazed is simply a strip with a through hole 39 for weight reduction. The other end is inserted into a groove 40 provided in the armature portion 29 and fixed to the armature portion by brazing or the like. The movable part 37 formed in this way
In this case, since the lever 38 does not have the bent portions 32, 32 as in the movable portion 24 shown in FIG. 2, the weight of the lever 38 is reduced, and therefore the printing speed of the printing wire 5 is increased. Further, in the movable part 37, the lever 38 can be made of ceramic, so if this is done, the lever 38 can be made of ceramic.
It can be made lighter than when it is made of metal, and as a result, the printing speed of the arrow tension printing wire 5 can be increased.

FIG. 6 shows a lever 41 made of synthetic resin that corresponds to the lever 38 in FIG. By doing so, it is fixed to the armchair portion 29. The lever 41 is made of synthetic resin in order to reduce the weight of this part and increase the printing speed of the printing wire 5.

If the movable part that drives the printing wire 5 is constructed as shown in FIGS. 5 and 6, it becomes easy to manufacture the print head so that the printing characteristics of the printing wire 5 are uniform. This is the same as the case of the movable part 24 shown in FIG.

〔Effect of the invention〕

As described above, in the present invention, in the print head of a wire dot printer that drives a print wire and prints dots with one end of the print wire, the other end of the print wire is fixed to the tip of a lever, and the lever is Its base is fixed to an armature forming part of a closed magnetic circuit and pivoted by the magnetic flux in this closed magnetic circuit, the armature being integrally formed with an arm-shaped spring supporting the armature. Therefore, this configuration has the effect of providing a print head that is easy to manufacture so that the printing characteristics of each of the plurality of printing wires are uniform.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of the first embodiment of the present invention, and FIG.
Figure 3 is a perspective view of the main parts of the movable part in the figure, and Figure 3 is an explanatory diagram of the manufacturing process of the support part in Figure 2, Figure (5) and Figure (B).
, the same figure (q is a state diagram in each different process, the fourth
The figure is an explanatory diagram of the manufacturing process of the lever in Figure 2.
5), the same figure (uniform, the same figure (q is a state diagram in each different process. FIGS. 5 and 6 are perspective views of the main parts of each movable part in the second and third embodiments of the present invention, Fig. 7 is a longitudinal sectional view of a conventional print head, Fig. 8 is a view taken along arrow P of the main part in Fig. 7, and Fig. 9 is a sectional view taken along line XX in Fig. 8. 2.28...・Spring part, 4... Armature, 5.・
・Print wire, 22.36...Print head, 26,3
8゜41... Lever, 29... Armature section as an armature. 1 closed 2nd figure f 3 figure 40 'is figure o 61! 1 year 7 figure

Claims (1)

[Claims] In a print head of a wire dot printer that drives a print wire and prints with one end of the print wire, the other end of the print wire is fixed to the tip of a lever, and the base of the lever forms a part of a closed magnetic path. A print head for a wire dot printer, characterized in that the print head is fixed to an armature driven by magnetic flux in the closed magnetic path, and the armature is integrally formed with an arm-shaped spring portion that supports the armature.