JPH0673963B2 - Printing wire for wiredot printers - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improvement in a printing wire for a wire dot printer used in a computer terminal processing machine, a word processor, or the like.

[0002]

2. Description of the Related Art Impact printers and non-impact printers have been well known as printers for computer terminals, word processors, etc. Of these, impact printers are currently in widespread use due to their advantages over non-impact printers, such as lower cost, higher reliability, and the ability to make multiple copies at the same time.

Impact printers are further divided into those that use specific types and wiredot printers that do not use types but instead create characters using multiple dots.Of these, wiredot printers do not use specific types and are therefore widely used in Japanese word processors and the like that require a large number of characters.

Further, wire dot printers include wire dot printers which print when the magnet is driven, and shuttle printers which cut the print when the magnet is driven.

This wire dot printer is shown in FIG.
As shown in the figure, there are multiple armature 1s inside the head case.
Each armature 1 is supported at one end by a core 2 (or a head case), and the other end is constantly biased by a reset spring 3 so as to move away from the core 2 by a fixed distance.

Printing wires (pins) 4 are fixed to the other ends of the armatures 1 by brazing or the like, and the printing wires 4 are slidably guided and supported by guides 5, 5'. A coil 6 is wound around the core 2, and the core 2 and the coil 6 constitute an electromagnet.
By passing a current through the coil 6, the biasing force of the reset spring 3 is overcome and the armature 1 is pulled to the core 2.
It is designed to be sucked in.

Therefore, in this printer, when the coil 6 (electromagnet) is energized, the armature 1 is attracted to the core 2, and the printing paper 8 on the platen 7 is pulled by the printing wires 4.
Printing can be performed via ribbon 9.

As shown in FIG. 4, the shuttle printer has a plurality of armature 1 disposed in a head case, and each armature 1 has one end attached to a core 2 (or head case) and the other end attached to a spring 3'.
The armature 1 is supported at a fixed distance from the core 2. On the opposite side of the armature 1, a printing wire (pin) 4 is provided.
is fixed by brazing or the like, and this printing wire 4
are slidably guided and supported by guides 5, 5'.

A coil 6 is wound around the core 2, and the core 2 and the coil 6 form an electromagnet. When a current is passed through the coil 6, the armature 1 is attracted to the core 2.

Therefore, this type of printer has a coil 6
By energizing the electromagnet, the armature 1 is attracted to the core 2, and by cutting off the current, the restoring force of the spring 3' is used to print on the printing paper 8 on the platen 7 via the printing wire 4 via the ink ribbon 9.

As mentioned above, the printing wires 4 of such a wire dot printer are pressed against the platen 7 via the armature 1 by the attraction or release of the electromagnet, causing the tip to be struck and forming an image on the printing paper 8 as it slides over the printing medium such as an ink ribbon 9. Therefore, the printing wires are required to be wear-resistant and impact-resistant, and various materials have been developed and used, such as cemented carbide, powdered high-speed steel, pure tungsten, and cobalt-based alloys.

[0012]

However, conventionally known printing wire materials, such as cemented carbide, are resistant to sliding and abrasion, but are brittle and therefore vulnerable to bending moments, making them prone to breakage. Furthermore, they are expensive and have a high specific gravity (specific gravity 14.0), which means they consume a lot of energy when printing dots, resulting in high running costs.

Furthermore, pure tungsten is relatively inexpensive, but has a higher specific gravity than cemented carbide (specific gravity 19.
2) Although relatively high-speed printing is possible with seven or nine wires, printing complex characters such as Chinese characters requires 24 or 36 wires, making it practically unusable as a printer for a Japanese word processor, for example.

Furthermore, powdered high speed steel (specific gravity 8.15) or cobalt alloy (specific gravity 8.3) is more expensive than pure tungsten but is cheaper than cemented carbide and also has a small specific gravity.

Therefore, for example, the printing speed of a powder high-speed steel 24-wire printer is about 40 to 80 seconds when printing only Chinese characters.
It is capable of high-speed printing at approximately 120 to 240 characters per second for mixed kana and hiragana characters, and is therefore currently the mainstream printing wire for printers with a large number of wires, such as 24 or 36.

However, in the case of powder high speed steel or cobalt alloy, when joining with the head part (armature),
When brazing with silver solder, the brazing temperature (approx. 700-800°C)
At temperatures above 50°C, a phase transformation occurs, making the material brittle, making it practically difficult to use brazing, which is the strongest and most stable method, and mechanical joining methods such as caulking must be used.
The joints with the head components tend to come off. As mentioned above, none of the materials fully satisfied all of the functions required for a printing wire, such as abrasion resistance, impact resistance, brazing ability, price, and weight.

[0017]

According to the present invention, a printing wire for a wire dot printer has a composition of 99.0% or more molybdenum and an elastic modulus of 20.00
According to the present invention, a print wire for a wire dot printer is obtained, characterized in that the composition of the print wire is 99.0% or more of molybdenum and the tensile strength is 16.0 kgf/ ^mm2 or more.
The present invention provides a printing wire for a wire dot printer characterized by a wear resistance of 100 kgf/ ^mm2 or more. Here, in the present invention, it is preferable that the amount of wear is 100 μm or less after 100 million dots. This provides good impact resistance and improves brazability.

[0018]

[Example] A material that has the abrasion resistance, impact resistance, and brazing properties required for use as a printing wire material in wire dot printers.
Molybdenum was selected as a lightweight and inexpensive material, and processing was carried out under various conditions.
% or less was brittle and had poor wire workability, so could not be processed into wire.

Therefore, the diameter is 0.3φ and the purity is 99.0%,
having a composition of 99.5% and 99.95% molybdenum;
Molybdenum wires having different elastic moduli were prepared and incorporated into the 24-wire wire dot printer shown in FIG. 3, and a dot printing test was carried out 100 million times.

The modulus of elasticity was adjusted by selecting the total reduction rate from the ingot and the annealing conditions, and the tensile strength was adjusted by annealing when the wire was processed to the final diameter. The test results are shown in Table 1 and Figure 1.

[0021]

[Table 1]

The amount of wear shown in Table 1 was measured in μm units at the tip of the printing wire, 2) wear resistance was determined by the presence or absence of breakage or bending after the test, 3) specific gravity was measured by the underwater method, and 4) brazing property was measured by using a commercially available silver solder at 845°C.
After brazing at 200°C, the armature 1 was fixed to clamp C as shown in Figure 2 and a 90-degree bending test was carried out. 5) Tensile strength was measured using a tensile tester. The above test results show that there is a correlation between wear resistance and elastic modulus, and when the elastic modulus was 18 x ¹⁰³ kgf/ ^mm2 or less, the wear amount exceeded 100 μm, and the tensile strength of these was also low at 150 kgf/ ^mm2 or less.

In terms of impact resistance, the material was soft and did not break at all, but the modulus of elasticity was 16x
When the pressure was below 10 ³ kgf/mm ² , bending occurred in some cases.

From the above results, molybdenum wire with a purity of 99.0% or more, an elastic modulus of 20×10 ³ kgf/mm ² or more, and a tensile strength of 160 kgf/mm ² or more can be used satisfactorily as a printing wire for a wire dot printer.
The shape of the printing wire was the same for all of the straight, stepped, and tapered types.

[0025]

As explained above, according to the present invention, the product has abrasion resistance and impact resistance, and also has good brazing properties.
Furthermore, it is possible to provide a lightweight and inexpensive printing wire for a wire dot printer, which has the effect of reducing the running costs of the wire dot printer and improving its durability and reliability.

[Brief explanation of the drawings]

FIG. 1 is a diagram showing the relationship between wear amount and elastic modulus of the present invention.

FIG. 2 is a schematic diagram of a test for determining brazability of the present invention.

FIG. 3 is a schematic diagram of a conventional wire dot printer.

FIG. 4 is a schematic diagram of a conventional shuttle printer.

[Explanation of symbols]

1 Armature 2 Core 3 Reset spring 4 Printing wire (pin) 5, 5' Guide 6 Coil 7 Platen 9 Ribbon

Claims (2)

[Claims] 1. A printing wire for a wire dot printer, characterized in that the composition of the printing wire is 99.0% or more of molybdenum and the modulus of elasticity is 20,000 kgf/mm ² or more. 2. A printing wire for a wire dot printer, characterized in that the composition of the printing wire is 99.0% or more of molybdenum and the tensile strength is 160 kgf/mm ² or more.