JPH0425341B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a spring material used in a dot printer, and particularly to a spring material used to regulate the operation of a printing wire (dot pin) and to soften the impact applied to the printing wire. (Prior Art) Generally, a dot printer is equipped with a printing mechanism as shown in FIG. This printing mechanism consists of an armature 1 to which a printing wire (not shown) is attached;
an arm 2, a leaf spring 3 whose ends are brazed to the armature 1 and the arm 2 with silver solder 5, respectively;
A tungsten spring material 4 is soldered to the arm 2 with silver solder 5. Brazing with silver solder is generally performed at a temperature of 600 to 900°C. By the way, when a tungsten wire formed from pure tungsten (hereinafter referred to as pure tungsten wire) is used as the above-mentioned tungsten spring material 4, the primary recrystallization start temperature of the pure tungsten wire is
800-900℃, so as mentioned above 600-900℃
If brazing is performed, the wire becomes brittle. Therefore, conventionally, incandescent tungsten wire doped with Al ₂ O ₃ , K ₂ O, or SiO ₂ and has a high recrystallization temperature (hereinafter referred to as doped tungsten wire) has been used as a spring material. is 1~
30 weight ppm, Si 1~20 weight ppm, K 50~100
Weight ppm is doped. In the above-mentioned doped tungsten wire, primary recrystallization occurs at 1400° C. or higher because K ₂ O suppresses the growth of crystal nuclei. (Problems to be Solved by the Invention) However, in the case of conventional doped tungsten wires, K ₂ O particles may be dispersed non-uniformly due to variations in dopant during the doping process, and the diameter of the wire may vary. The thinner the wire, the more areas where non-uniformity will occur. As a result, a portion of the wire has a composition similar to that of a pure tungsten wire, and the primary recrystallization temperature of that portion decreases, making it brittle during brazing.
Therefore, when a conventional doped tungsten wire is used as a spring material, there is a problem that the spring material may break. Furthermore, for conventional doped tungsten wire,
There is a problem that cracks, chips, etc. occur during bending. (Means for Solving the Problems) The present invention is used in dot printers, and in the spring material that regulates the operation of the printing wire and softens the impact applied to the printing wire, aluminum is added at 1 to 30 ppm by weight and silicon is added to the spring material. 1 to 20 weight
ppm, and potassium over 10 ppm by weight, 50 weight
A spring material for dot printers that contains less than ppm and the remainder is tungsten. (Example) The present invention will be described below with reference to Examples. Blue oxide was doped with various amounts of Al ₂ O ₃ , K ₂ O, and SiO ₂ to produce blue oxides with different amounts of dopants added. The blue oxide to which these dopants were added was reduced to obtain doped tungsten powder. After pressing these doped tungsten powders,
Temporary sintering was performed. Thereafter, the temporary sintered body was sintered by directly applying electricity in a hydrogen atmosphere to produce an ingot. Next, these ingots were subjected to rolling processing, intermediate heat treatment, and rolling processing, and then drawn. Furthermore, these drawn wire materials were subjected to linear electrolysis to produce doped tungsten materials with a diameter of 0.3. After bending these doped tungsten wires, the temperature is 850±
The arms were silver-brazed at 5°C. Thereafter, a bending test was conducted on these doped tungsten wires (spring materials). For the bending test, 200 of each of the above-mentioned doped tungsten wires were prepared, silver brazed to the arm (temperature 850±5°C), and then the bending test was conducted. The bending test was carried out using a fixed base 6, which had one corner formed into a spherical shape with a predetermined radius, as shown in Figure 2.
Hold the doped tungsten wire between 7 and 90 to the left and right.
Fold it once. In addition, when bending, a backing plate 8 is brought into contact with the doped tungsten wire, and force is applied on the backing plate 8 to bend the wire. The results of this bending test are shown in the following table.

[Table] As shown in the above table, the dopant added to the doped tungsten wire had approximately constant amounts of Al and Si, and varied the amount of K. As is clear from the table above, when the amount of K is less than 10 ppm by weight, the primary recrystallization temperature becomes 850°C or lower, which results in embrittlement and an extremely low number of bends. The number of broken pieces less than 3 times is extremely high. Similarly, when the amount of K is 50 ppm by weight or more, the average value of the number of bends is 10 ppm by weight.
This is an improvement compared to Suemitsu's case. However, there are some broken pieces that are bent three times or less. That is, the doped molybdenum wire needs to be bent four times or more in terms of its strength (the number of broken wires that are bent three times or less needs to be zero). On the other hand, if the amount of K is 10 ppm or more by weight, 45
When the weight is less than ppm, the average value of the number of times of bending is high, and the number of broken pieces when the number of times of bending is 3 or less is zero. Although not shown in the table, it was found that if the amount of K was less than 50 ppm by weight, the number of broken pieces after bending three times or less was zero. Furthermore, the amount of K shown in the table is 30 ppm by weight and 60 ppm by weight.
Figure 1 shows the relationship between the number of bends and the number of broken wires for a ppm doped tungsten wire. 1st
As shown in the figure, in the case of a doped tungsten wire with a K content of 60 wt ppm, breakage occurs quickly after one bending, but in the case of a doped tungsten wire with a K content of 30 wt ppm, breakage occurs after the number of bends. Breakage occurs for the first time in the 7th inning. In addition, doped tungsten wires to which the dopants shown in the table above were added were incorporated into 9-pin type dot printers as spring materials, and a mounting test was conducted. As a result, the doped tungsten wire containing K in an amount of 10 ppm or more and less than 50 ppm by weight did not break even when 100 million dots were printed. That is, there was no breakage due to printing of 100 million dots. On the other hand, the amount of K is 10
In the case of doped tungsten wires other than those with weight ppm or more and less than 50 weight ppm, several to dozens of wires were broken after printing 100 million dots. Note that in the above table, the amounts of Al and Si are almost constant, but the amounts of Al and Si may be added in the conventional manner of 1 to 30 ppm by weight and 1 to 20 ppm by weight, respectively. (Effects of the Invention) As explained above, the spring material for a dot printer according to the present invention has excellent durability, so there is extremely little risk of breakage, and a highly reliable dot printer can be provided.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the number of folds and the number of folds, FIG. 2 is a diagram showing the method of a folding test, and FIG. 3 is a diagram schematically showing the main parts of the printing mechanism of a dot printer. 1... Armature, 2... Arm, 3... Leaf spring,
4...Tungsten spring material, 5...Silver solder, 6,7...
Fixed base, 8...Packing board.

Claims (1)

[Claims] 1. A spring material used in dot printers that regulates the operation of the printing wire and softens the impact applied to the printing wire, containing 1 to 30 ppm by weight of aluminum, 1 to 20 ppm by weight of silicon,
A spring material for dot printers, which contains potassium in an amount of 10 ppm or more and less than 50 ppm by weight, with the balance being tungsten. 2. A spring material for a dot printer as set forth in claim 1, characterized in that the number of times of 90-degree bending is four or more times.