JPS592856A - Wire guide for wire dot printer - Google Patents

Abstract

PURPOSE:To provide a low cost titled wire guide excellent in the wear resistance as well as in the dimensional stability and durability, etc. as a whole by using a resin composition having a polyamide resin blended with a specified fibrous substrate and the like as a tip guide section. CONSTITUTION:The tip guide section 1 of a wire guide is made up of a resin composition in which A) polyamide resin is blended with preferably 10-40wt% of a fibrous substrate selected from among B) carbon fiber, silicon carbide fiber, metallic fiber, aromatic polyamide fiber and polyacetal fiber or preferably 5- 15% of mixture of said fibrous substrate and inorganic powder-like substrate (preferably, a silica, alumina, glass, silicon carbide, etc.).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire guide for a wire dot printer used as an output device.

In the wire guide of such a wire dot printer,
The tip guide part is particularly required to be wear resistant as it comes into contact with the operating printing wire while the printer is in use, and the frame part must withstand long-term use and change due to environmental changes such as temperature and humidity. Dimensional stability is also required because the gap with the printing surface must be maintained constant even if

For this reason, conventionally the entire wire guide was made of metal such as hardened steel, or the tip guide part was made of ruby-containing ceramic, the frame part was made of metal, and these were integrally joined. . However, wire guides made of metal do not necessarily have sufficient wear resistance at the tip guide portion, and require time and labor to manufacture, making them unsuitable for mass production and resulting in high costs. In addition, wire guides whose tip guide portions are made of ruby-containing ceramic have excellent wear resistance, but because of the bonding process involved in manufacturing, they are more difficult to mass produce than wire guides made of only metal, and are costly. It also had the disadvantage of being expensive.

The wire guide of the present invention has excellent wear resistance at the tip guide portion, and has excellent dimensional stability and durability as a whole.
Since it can be easily molded using normal plastic molding methods, mass production and cost reduction can be achieved. It is made of a resin composition containing an inorganic powder base material, and the fibrous base material is selected from carbon fibers, silicon carbide fibers, metal fibers, aromatic polyamide fibers, and polyacetal fibers. This is a wire guide for wire dot printers.

FIG. 1 shows an example of the wire guide of the present invention, in which (1) is a tip guide portion and (2) is a frame portion.

In the wire guide of the present invention, at least the tip guide portion (1) is molded from a polyamide resin containing a fibrous base material. Polyamide resin originally has excellent abrasion resistance, but when a fibrous base material is added as a reinforcing material, the abrasion resistance is further improved, and it can be used as the tip guide of a wire guide with properties equal to or better than metal. Become.

In the present invention, the fibrous base material blended into the polyamide resin is specifically the above-mentioned material, but the reinforced side of these materials has particularly excellent abrasion resistance compared to other reinforcement materials, and has other properties. For example, heat resistance etc. are also improved.

Furthermore, in the present invention, an inorganic powder base material can be used together as a reinforcing material. This inorganic powder base material is not particularly limited, but silica, alumina, glass, silicon carbide, etc. are preferable. By adding these inorganic powder base materials, wear resistance, heat resistance, thermal conductivity, and dimensional stability are improved.

Regarding the blending amount of these reinforcing materials, the fibrous base material is 5 to 50% (weight%, the same hereinafter) based on the entire composition, preferably Vil O ~ 4096, and when the inorganic powder base material is used together, the composition The amount of the fibrous base material is 5 to 40 (preferably 10 to 35%), and the amount of the inorganic powder base is 5 to 40 to the entire product.
20% (preferably 5 to 15 inches). The frame portion can be made of the same material as the tip guide portion, but other materials may be used if dimensional stability against environmental changes such as temperature and humidity is particularly required.

In order to manufacture the wire guide of the present invention, injection molding,
Plastic molding methods such as transfer molding can be used. When the tip guide portion and the frame portion are molded from different materials, the tip guide portion is molded first and then the other portions are molded, or vice versa. In this case, since the purpose of the present invention is to improve acoustic properties and reduce manufacturing costs, it is most effective to use the so-called two-color molding method.
An insert molding method for molding the second part is also possible.

Next, as an example, typical wire guides of the present invention are shown below.

EXAMPLE Wire guides having the shape shown in FIG. 1 were injection molded using polyamide resin compositions having the following formulations.

Example 1 Polyamide resin 70q6 carbon fiber 30cm Example 2 Polyamide resin 60cm Aromatic polyamide fiber 30cm
% Silicon carbide powder (100 mesh passes) 10% Comparative example A wire guide made of 100% polyamide resin was attached to a 9-dot matrix printer, printed at a printing speed of 120 characters/second, and the number of dots until the printed characters became unclear was measured.

The results were as follows.

Example 1 25QOOO million dots Example 2 40QOOO million dots Comparative example 10QOOO million dots As described above, a wire guide for a wire dot printer molded using the polyamide resin composition of the present invention is as follows:
Since it has excellent abrasion resistance and other properties are also good, it can maintain a high level of printing quality over a long period of time.

[Brief explanation of drawings]

1 and 2 are examples of the wire guide of the present invention.

Claims (1)

[Claims] (1) The tip guide portion of the wire guide is not made of a resin composition comprising a polyamide resin and a fibrous base material, or a fibrous base material and an inorganic powder base material, and the fibrous base material is carbon fiber,
A wire guide for a wire dot printer, characterized in that the wire guide is selected from silicon carbide fibers, metal fibers, aromatic polyamide fibers, and polyacetal fibers.