JPH0415736B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a dot wire for a dot printer. [Prior Art] The dot wires in a print head for a dot printer are arranged approximately in a line with their base ends fixedly supported by leaf springs and their tips guided by pin guides, and usually in a state where the leaf springs are bent. In this case, when the deflection of the leaf spring is released by electromagnetic force, the dot wire is ejected from the pin guide of the print head.
It is pressed onto the paper via an ink ribbon. Such dot wires are subjected to repeated impact loads, and although this is extremely small during printing due to the placement of the dot wires in relation to the leaf springs, the dot wires are subject to repeated impact loads during repeated printing due to reasons such as the dot wires coming into contact with the printing surface at an angle. Uneven wear occurs on the end face,
Printing becomes unclear. As a means to increase the wear resistance of dot wire,
For example, there is one disclosed in Japanese Patent Application Laid-open No. 58-193166. In this conventional technology, high-speed steel is used as the base material of the dot wire, titanium metal is vapor-deposited on the surface of the base material in a vacuum atmosphere, and then exposed to a nitrogen gas atmosphere to form a ceramic coating made of titanium nitride. However, the printing speed is limited due to the relatively high specific gravity of the high-speed steel used as the base material, and the process to form a hard coating on the surface is complex and time-consuming, resulting in low productivity and high costs. The problem is that it gets bulky. Therefore, cemented carbide, tungsten, etc., which have excellent wear resistance and impact load resistance, are generally used for dot wires, but these materials are quite expensive and have a high specific gravity, so it is difficult to increase the printing speed. was being prevented. [Problems to be Solved by the Invention] An object of the present invention is to provide a dot wire that can be manufactured at low cost with a simple process, is lightweight overall, has sufficient hardness on the surface, and is advantageous for high-speed printing. be. [Means for Solving the Problems] In order to achieve the above object, the present invention has a structure in which a hard coating of nickel plating with a thickness of 2 to 3 μm is provided on the surface of a piano wire with a wire diameter of 0.150.35 mm. be. The dot wire according to the present invention is obtained by degreasing the surface of the piano wire and then immersing it in a nickel plating bath to perform electroless nickel plating. Next, the piano wire was pulled out of the nickel metal tank and heated to 80 to 180
Keep at temperature of °C for about 1 hour. Through this heat treatment, the surface hardness exceeds 700Hv and the thickness is 2~
A nickel plating film of 3 μm is formed on the surface of the piano wire. [Function] The present invention uses piano wire, which has a lower specific gravity than conventional high-speed steel, as the base material. Piano wire has excellent impact load resistance, but if rust develops on the surface after long-term use, it will contaminate the printed surface, and it cannot be said to be sufficient against uneven wear as described above. According to the present invention, electroless nickel plating is applied to the surface of piano wire with a wire diameter of 0.15 to 0.35 mm in order to prevent surface rust and form a hard coating having a hardness comparable to that of high-speed steel. 1 at a temperature of 80 to 180℃ to increase the hardness of the nickel-metallic coating.
Heat treatment for an hour. This heat treatment improves the surface hardness of the nickel plating film by 10 to 20%. [Embodiments of the Invention] A method for manufacturing a dot wire according to the present invention will be described based on Examples. First, the piano wire is ultrasonically cleaned with Triclean solution and thoroughly degreased. Degreased piano wire with nickel chloride 20g/lt,
Temperature approx. 27g/lt of sodium hypophosphite, 16g/lt of sodium succinate (lt stands for liter)
It was immersed in a plating solution at 100°C for about 10 minutes. After that, the piano wire was pulled out of the nickel plating bath and the temperature was 120.
It was left in an atmosphere at ℃ for about 1 hour. By the heat treatment described above, a nickel plating film 4 having a thickness of about 2 μm and a surface hardness exceeding 700 Hv and having excellent wear resistance was formed on the surface of the piano wire 3. Similar results were obtained using sodium acetate or sodium citrate in place of sodium succinate. A micrograph (magnification: 200x) of a cross section of the coating of the dot wire thus obtained is shown in FIG. Table 1 shows a comparison of the properties of the conventional dot wire and the dot wire according to the present invention. Table 1 also shows samples that were not heat treated after nickel plating in the manufacturing process of the present invention. Hardness (Hv)
is the result of measurement using a micro-Vickers hardness meter.

[Table] Heat treated at ℃.
As shown in FIG. 1b, the piano wire 3 may be cut into predetermined dimensions and then nickel-plated, but as shown in FIG. 1a, the long piano wire 3 may be nickel-plated continuously. Even if the dot wire is cut into predetermined dimensions after processing, it still functions as a dot wire. In the latter case, the hard coating 4 made of nickel plating is not formed on the cut surface, but the surrounding surface is protected by the hard coating 4 made of nickel plating, so the occurrence of rust is suppressed, and as explained at the beginning, Since the dot wire 2 is pressed against the printed surface at a slight inclination, the hard coating applied to the peripheral surface of the piano wire 3 suppresses its wear. [Effects of the Invention] As described above, the present invention provides a piano wire with a wire diameter of 0.15 to 0.35 mm, with a thickness of 2 to 2 mm coated with nickel plating on the surface of the piano wire.
Since it is equipped with a 3 μm hard coating, it has the following effects. (a) Because it uses piano wire as a base material, it has a lower specific gravity than conventional cemented carbide, tungsten, high-speed steel, etc., making it possible to increase printing speed. (b) By applying electroless nickel plating to the surface of piano wire and then heat-treating it at a temperature of 80 to 180°C, even if the nickel plating film is thin, it exhibits the same hardness as conventional tungsten or high-speed steel. , there is no problem with wear resistance. (c) Since a hard coating can be continuously formed on a long and thin piano wire, the process is simple and an inexpensive dot wire can be provided. (d) Because the heat treatment temperature is low and the temperature range is wide,
Temperature control is easy and heat costs are saved.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a dot wire according to the present invention, and FIG. 2 is a microscopic photograph showing the metal structure of a cross section of a hard coating of the same dot wire. 2...Dot wire, 3...Piano wire, 4...
Hard coating.

Claims (1)

[Scope of Claims] 1. A dot wire characterized in that a piano wire with a wire diameter of 0.15 to 0.35 mm is provided with a hard coating of 2 to 3 μm thick on the surface thereof by nickel plating. 2 Thickness 2 on the surface of piano wire with a wire diameter of 0.15 to 0.35 mm
After ~3 μm electroless nickel plating, the temperature
1. A method for producing a dot wire, which comprises performing a heat treatment at 80 to 180°C for about 1 hour.