JPH021330A - Manufacture of movable part of wire hot printing head - Google Patents

Abstract

PURPOSE:To avoid deterioration of a lever material by oxidation near a joint by a flux and deterioration of strength by corrosion of the joint or the like by a method wherein a base park of a lever is fitted in a joining groove at a top of an armature, and both are joined by diffusion at a specific temperature under vacuum. CONSTITUTION:Materials of a lever 18 and an armature 19 are mutually made of metal containing a same atom (for instance, iron and cobalt) or diffusible metal. A base part of the lever 18 made of such a material is fitted into a fitting groove 21 provided at a top of the armature 19. The lever 18 and the armature 19 are heat-treated under vacuum to be joined by diffusion at a temperature of 1,100 deg.C or higher and under melting points of the lever 18 and the armature 19 under this state. Consequently, breakage and peeling of a joint of the lever 18 and the armature 19 can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a movable part of a wire dot print head used in an impact printer, and more specifically, a lever to which a print wire is attached, an armature supported by a leaf spring, and a movable part of a wire dot print head used in an impact printer. The present invention relates to a method of manufacturing a movable part comprising:

[Conventional technology]

As is well known, impact printers have advantages such as low cost and the ability to print on a wide variety of media, so they are used in a wide variety of fields, including output devices for information processing systems. Although the performance has been improved,
In recent years, there has been an increasing demand for higher printing speeds and higher reliability of print heads.

In order to meet these demands, the spring-charged wire dot print head used in impact printers has a movable part that consists of a lever to which the print wire is attached and an armature supported by a leaf spring. The challenge is to improve the strength so that this movable part can operate stably over a long period of time without causing damage due to fatigue or the like.

An example of a spring-charged wire dot print head will now be described with reference to FIG.

FIG. 4 is a side view of the wire dot print head, with the lower half shown in cross section to clarify the internal structure.

In the figure, 1 is a printing wire, 2 is a lever with the base of the printing wire l fixed to its tip, and 3 is an armature with the base of the lever 2 fixed to its tip. supported at the tip,
Furthermore, the base of this temporary spring 4 is fixed to an armature supporter 5.

6 is a first yoke, 7 is an annular magnetic spacer, 8 is an annular second yoke, 9 is an annular permanent magnet, and 10 is a plurality of cores 11 arranged in a substantially circular or elliptical shape in the center. In the formed base, the first yoke 6, the magnetic spacer 7, the second yoke 8, and the permanent magnet 9 are laminated in a predetermined order on the outer peripheral edge of the base 11. By fixing the armature supporter 5 inside the yoke 6, the armature 3 is connected to the core 1.
It extends to a position opposite to 1.

It goes without saying that the same number of movable parts as the cores 11 are provided, each consisting of the printing wire 1, the lever 2, the armature 3, and the leaf spring 4.

12 is a degaussing coil attached to the outer periphery of each core 11; 13
is a cover attached to the outside of the first yoke 6, and the tips of each printing wire l are guided to the tip of a guide portion protruding from the center of the cover 13 and regulated so as to be arranged in a predetermined arrangement. ing.

14 is an ink ribbon, 15 is a printing medium such as paper, 16
is a platen placed so as to face the guide portion of the cover 13 with the ink ribbon 14 and printing medium 15 interposed therebetween.

Here, the operation of the single-rotation portion in the wire dot print head having the above structure will be briefly explained.

First, when the demagnetizing coil 12 is not excited, the magnetic flux of the permanent magnet 9 is the second yoke 8=+magnetic spacer 7=:pi-
It passes through a magnetic circuit consisting of a yoke, 6-sided armature, 3 cores, and a base 10, and due to the magnetic attraction force generated between the armature 3 and the core 11, the armature 3 is attracted to the core 11 while bending the leaf spring 4. Ru.

At this time, the printing wire 1 is moved to the lever 2 by this suction operation.
At the same time, the printing wire and the lever 2 are displaced toward the base 10 side, and this displaced position is set as the initial position of the printing wire and the lever 2.

When the degaussing coil 12 is energized and energized from this state, the magnetic flux of the permanent magnet 9 is canceled and the armature 3 is released from the attraction force of the core 11. As a result, the leaf spring 4 is restored and the armature 3 is moved to the core 11. Operate away from.

This separating operation of the armature 3 drives the printing wire 1 together with the lever 2, so that the tip of the printing wire 1 protrudes from the tip of the guide portion of the cover 13, and the protruding tip passes through the ink ribbon 14 and printing medium 15 to the platen. 1
6, the ink ribbon 1 is applied to the printing medium 15.
4 ink is transferred as dots.

Thereafter, the printing wire l starts to return in the opposite direction to the protruding direction due to the repulsive force of the impact, and at the same time, the power to the degaussing coil 12 is cut off, so that the magnetic flux of the permanent magnet 9 passes through the magnetic circuit. , again armature 3 is core 11
When the printing wire 1 is attracted, the printing wire 1 returns to the initial position together with the lever 2.

The above is one printing operation performed by the rotating part, but in actual printing, each moving part is selectively driven according to the printing data, and dot-structured characters, etc. are printed on the printing medium 15. .

By the way, in the conventional movable part of such a wire dot print head, in order to achieve high-speed printing, maraging steel, Elgiloy, etc., which are generally known as high-strength spring materials, are used as the material of the lever 2, and The weight is reduced by using a cobalt high magnetic flux density material such as 1 to 5% silicon steel or permenda as the material of the armature, and the base of the lever 2 and the tip of the armature 3 made of such material are bonded and fixed. For this fixing method, wax welding is used.

In general, brazing welding uses a brazing material that has a melting point lower than the melting point of the metals that are bonded to each other, and a component that is the same type or has a strong affinity with the metals that are bonded to each other is mixed into the brazing material.
By melting this brazing material in a non-oxidizing atmosphere gas, the brazing material and the metal to be fixed are brought into close contact and bonding strength is obtained.

Therefore, in the past, silver solder welding was usually used to join and secure the base of the lever 2 and the tip of the armature 3, but if even higher strength was required, it was necessary to properly select the lever material and armature material. Copper brazing welding, etc. is performed.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology, when the printing wire hits the platen during the printing operation, and when the core re-adsorbs the armature, the movable parts consisting of the printing wire, lever, and armature are subjected to impact, and the lever and armature are damaged. There was a problem in that the joints of the parts were bent or peeled off.

One possible reason for this is that since flux is used in silver brazing welding, the strength of the lever material deteriorates due to oxidation in the vicinity of the joint due to the flux. Also,
Copper solder welded items are easily oxidized in humid air or air containing chlorine or sulfur, which makes the joints more likely to corrode and deteriorate their strength.

Therefore, these problems are one of the major obstacles to achieving high reliability of the print head.

The present invention was made in order to solve such problems, and an object of the present invention is to realize a highly reliable method of manufacturing the movable part of a wire dot print head that can prevent the joint between the lever and the armature from breaking or peeling. That is.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention makes the material of the lever and armature a metal that contains the same atoms or a metal that is easily diffused, and connects the joint of the lever base to the tip of the armature. By fitting into the joint groove provided and at a temperature of 1100°C or higher and lower than the melting temperature of the lever and armature,
By subjecting the lever and armature to heat treatment in a vacuum, they are diffusion bonded.

[Function] The present invention according to the above-mentioned means fits the base of the lever into the armature and diffusion-bonds the two, so there is no risk of deterioration of the lever material due to oxidation near the joint due to flux or damage to the joint, etc. as in the conventional method. Deterioration in strength due to corrosion can be eliminated.

As a result, the joint between the lever and the armature can be prevented from breaking or peeling off, thereby making it possible to realize a highly reliable movable part of the wire dot print head with sufficient joint strength.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing an example of a movable part of a wire dot print head manufactured according to the present invention.
18 is a printing wire; 18 is a lever to which the base of the printing wire 17 is fixed; 19 is an armature; in this embodiment, the lever 18 and the armature 19 are each made of a material containing the same atom or a material that is easily diffused. At the same time, the base of the lever 18 is made into a joint part 20,
Further, a joint groove 21 corresponding to the shape of the joint part 2o is provided at the tip of the armature 19, and this joint part 20 and the joint groove 2
1 are fitted, and then both are bonded by thermal diffusion in a vacuum.

Next, a method of manufacturing a movable part having such a structure will be explained.

Generally, in diffusion bonding, it is effective to use materials containing the same atoms, and in order to satisfy this condition, in this embodiment, the combination of materials for the lever 18 and armature 19 is as follows.

First, in combinations that include iron as the same atom, lever 1
8 is made of SK steel, and the material of armature 19 is made of 1 to 5% silicon steel.

In addition, in combinations containing cobalt as the same atom,
The material for the lever 19 is maraging steel, titanium alloy, or Elgiloy, and the material for the armature 19 is a high-density magnetic flux material containing Kobal 1, such as Permenda.

Joint portion 20 of lever 18 formed of such a material
The surface of the lever 18 and the inner surface of the joint groove 21 of the armature 19 are polished to be as flat as possible, and the joint part 20 of the lever 18 is pushed into the joint groove 21 of the armature 19 and fitted.

The pressure that the joint part 20 receives from the joint groove 21 at this time is
Here, it was designed in advance to be about 0.3 to 0.5 kg f /ct.

Thereafter, the lever 18 and the armature 19, in which the joint portion 20 and the joint groove 21 are fitted, are vacuumed to 1×10 Torr.
The lever 18 and the armature 19 are diffusion bonded at the fitting portion between the bonding portion 20 and the bonding groove 21 by placing the lever 18 and the armature 19 in a vacuum furnace at a temperature of 1,100° C. or higher for about 5 hours. However, the temperature is below the melting temperature for the lever 18 and armature 19.

Next, the results of the trial manufacture and durability test of the movable part according to this example will be described.

■, Lever 18: SK steel Armature] 9:1% silicon steel ■, Lever 18: Maraging steel Armature 1
9: For each permender combination, manufacture a movable part by silver solder welding and thermal diffusion, incorporate the movable part into the wire dot print head shown in FIG. The platen gap was set to 0.35 mm, and printing was performed continuously.

FIGS. 3 and 4 show the occurrence of failures such as bending and peeling at the joint between the lever 18 and the armature 19 at this time, that is, the strength of the joint.

Here, FIG. 3 shows the case of the combination (■) above, and FIG. 4 shows the case of the combination (■) above. In both figures, the horizontal axis is the total number of printed dots after printing starts, and The axis is the cumulative number of joint failures.

In addition, ○ in the figure is a movable part made by silver solder welding, and the mouth and △ and ・
is a movable part that uses heat diffusion, and the processing temperature for heat diffusion is 900°C for the mouth, 1100°C for △, and 1300° for △.
This is the case of C.

The reason why the heat treatment temperature was determined in this manner was to consider the temperature at which the vacuum furnace could stably maintain the temperature.

As is clear from this figure, in the combination (2) above, although the cumulative number of failures due to thermal diffusion at a temperature of 900 ''C exceeds that due to silver solder welding, the cumulative number of failures is 1100.
℃ and 1300°C heat diffusion has a lower cumulative number of failures than silver solder welding, especially at 1300°C.
The result was that the thermal diffusion was considerably lower than that by silver solder welding, and similar results were obtained for the combination (2).

The heat treatment time was approximately 5 hours for both combinations of (1) and (2) above. It is quite possible that the bonding strength changes depending on the heat treatment time, but in this experiment,
It was confirmed that by performing heat treatment at C for about 5 hours, it was possible to realize a movable part with sufficiently greater bonding strength than brazing welding.

FIG. 5 is an explanatory diagram showing the strength of the joint 20 when the pressure that the joint 20 receives from the joint groove 21 is changed. Here, the combination of lever 18 and armature 19 shown in (2) was used.

In the embodiment described above, the pressure that the joint portion 20 receives from the joint groove 21 was set to be about 0.3 to 0.5 kgf/cffl, but as seen in this figure, the pressure was set to 0.5 kgf/cffl. cIII or higher (0.7 k in this figure)
g f /cffl), 0.3 to 0.5 k
The results show that the occurrence of failure is lower than when the pressure is about 0.3 kg f /ci.
It was confirmed that it is sufficient if it is equal to or higher than /c+f1.

Moreover, FIG. 6 is an explanatory diagram showing the strength of the joint 20 when the degree of vacuum in the vacuum furnace is changed. Here, too, the lever 18 and armature 19 are of the combination of Vacuum degree I X I Ql. ,,,
, shows examples where the degree of vacuum is lowered and raised than that of .

As seen in this figure, the degree of vacuum is lXl0-37°,
, , and lXl0-'T. In all cases where the vacuum level is raised to 10-' Torr, almost the same results are obtained as in the case of a vacuum level of IX10-'Torr, and therefore, it is sufficient that the vacuum level in the vacuum furnace is 1X10-37°r or higher. confirmed.

It goes without saying that the present invention can achieve similar results not only with the above-mentioned silver soldering but also with a movable part that fixes the base of the lever and the tip of the armature by copper soldering.

Furthermore, in the above-described embodiments, metals containing the same atoms are used as materials for the lever and armature, but it is also possible to use metals that easily diffuse into each other as materials.

In this case, the metal material used is the above-mentioned SK steel or maraging steel for the lever, and the armature is made of, for example, a high-611 material containing Ni as the main component (79% Ni
, 5% Mo, 16% Fe) may be used.

K steel 2 maraging steel has Fe as its main component, and the melting point of this Fe is ~1535°C1, and N1, which is the main component of the highly magnetic material, is ~1455°C.

The diffusion coefficient of Fe-Ni is D = 1.3XI L12 [m2/s] at a temperature of 1100°C. Therefore, by selecting an appropriate degree of vacuum, the lever and armature made of the metal material were assembled in a vacuum furnace. If heat treatment is performed at a temperature of 1100° C. or higher and lower than the melting temperature of the material, the above embodiments can be joined in the same manner.

[Effects of the Invention] As explained above, the present invention fits the base of the lever into the joint groove at the tip of the armature and diffusion-bonds the two in a vacuum at a temperature within a certain range, which eliminates the need for flux as in the conventional method. This eliminates the deterioration of the lever material due to oxidation near the joint, and the deterioration of strength due to corrosion of the joint, etc. This prevents the joint between the lever and armature from breaking or peeling, ensuring sufficient joint strength. The effect is that it becomes possible to realize a highly reliable movable part of the wire dot print head.

In addition, titanium alloy has not been used much until now because it is difficult to weld with brazing, but in the present invention, titanium alloy is used as a material for the lever and armature in order to join the lever and armature by heat diffusion. This also has the effect of making it possible to manufacture moving parts that take advantage of titanium alloy's toughness and high corrosion resistance.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an example of the movable part of a wire dot print head manufactured according to the present invention, FIG. 2 is a side view of the wire dot print head, and FIG. Explanatory diagram showing strength, 4th
Figure 5 is an explanatory diagram showing the strength of the joint in brazing and diffusion bonding based on experiments, and Figure 5 is an explanatory diagram of the experimental results showing the strength of the joint when the pressure that the joint receives from the joining groove is varied. FIG. 6 is an explanatory diagram of experimental results showing the strength of the joint when the degree of vacuum in the vacuum furnace is changed. 4: Temporary spring 9; Permanent magnet 11: Core 12: Shaojiang coil 17: Printing wire 18 Lever 19: Armature 20: Joint portion 21: Joint groove 18 Lever A perspective view showing an embodiment of the present invention 1 Side view of the country wire rat printing hand Lever: Maraging steel armature: Number of printed dots when using permender (0 times) 0 Silver solder joint mouth diffusion bonding (900℃) Δ diffusion bonding (1100℃) 9 Diffusion bonding ( +31JO℃) Explanatory diagram showing the strength of the joint part by experiment Imported country ■ Lever: 81 (Steel armature: Number of printed dots when using 1% silicon steel (×10 times) 0 Silver solder joint diffusion bonding (91JUt: ) Δ diffusion Bonding (1100℃) ・Diffusion bonding (13t) 0℃) Explanatory diagram showing the strength of the bonded part through experiment Explanation 1 showing the results when the pressure applied to the joint is varied.
legitimate country

Claims (1)

[Claims] 1. The material of the lever to which the printing wire is attached at the tip and the armature supported by the leaf spring are metals that contain the same atoms or metals that are easily diffused, and the joint of the lever base is provided at the tip of the armature. The wire dot is fitted into a bonding groove formed by the wire dot, and the lever and the armature are heat-treated in a vacuum at a temperature of 1100° C. or higher and lower than the melting temperature of the lever and the armature, thereby diffusion bonding the two. A method of manufacturing the movable part of a print head.