JPS59111863A - Wire type dot matrix print head - Google Patents

Abstract

PURPOSE:To provide the titled print head of high reliability prepared by a method wherein the tungsten head wire, the top part of which a cemented carbide wire is attached to, is used as a print wire. CONSTITUTION:A wire type dot matrix print head is composed of the armature 2 brazed with a print wire 1 of a permanent magnet 4 and the york 7 for forming the magnetic circuit equipped with a coil 3 (the symbol 5 herein means the top wire guide and the symbol 6 means the intermediate wire guides). For the abovementioned head, the print wire prepared by brazing 1'' the cemented carbide wire 1' having high abrasion resistance to the top of the tungsten wire 1 having high resistance, is used. Further, the cemented carbide wire 1' has a fixed diameter (for example, 0.2mm.) and its length should preferably be about a length equivalent to the gap between the intermediate guide 6 and the top guide 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printhead for use in a wire dot matrix printer.

Conventionally, the wire portion of this type of dot matrix print head is made of carbide wire or tungsten wire itself, and carbide wire has less wear but less resistance than tungsten wire, and tungsten wire has higher resistance but less wear. It is larger than tungsten wire, and each has its advantages and disadvantages.

Conventionally, a stepped printed wire was used, with the tip of the tungsten wire being thinner and the back end being thicker. That is, because of the recent high demand for high-density printing, the wires are crowded at the tip of the print head, and the diameter of the wire tip naturally becomes small. For example, in a 24 print head, the tip diameter is 0.2wn. Therefore, the tungsten wire used is a stepped wire of 0.2 mm at the tip and 0.25 to 0.3 mm at the rear end. Therefore, since the tip portion is thin, it is subject to severe wear and causes problems such as dot removal.

On the other hand, carbide wires do suffer from much less wear than tungsten wires, but the wires often break, which also causes problems such as dots.

The present invention provides a reliable dot matrix print head by using carbide wire at the tip and tungsten wire at the rear in order to take advantage of the respective advantages of tungsten wire and carbide wire. .

Next, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, one embodiment of the present invention includes a wire 1, an armature 2, a coil 3, a permanent magnet 4, a tip wire guide 5, an intermediate guide 6, and a yoke 7 constituting a magnetic circuit. The structure is the same as that of a conventional wire-type dot matrix print head, and the operations and functions of each part are well known and will not be explained here.

Now, the wire 1 is fixed to the amachia 2 by brazing, and this part is made of tungsten. The tip portion 1' of the wire 1 is made of carbide and has very good wear resistance. The wire 1 and the tip portion 1' are connected by brazing or the like, so there is no problem in terms of service life.

Referring to FIG. 2, a print wire 1 made of tungsten material is brazed and fixed to an armature 2 as described above, as is conventional. The diameter of the tungsten wire is made as large as possible to reduce stress caused by impact force during printing. Furthermore, it becomes difficult to fall asleep.

The wire tip portion 1' is made of a superhard material and has a predetermined diameter, for example 0.2 mm. This part does not need to be very long; it is preferably about the length between the intermediate guide 6 and the distal guide 5, and is preferably used at a part that is almost straight on the curve of the print wire.

Tungsten 1 and carbide 1' are connected by brazing 1, and the connection is made at a position that is mainly subjected to only compression and not bending stress. Connections can also be made by drilling a hole on the thicker side, inserting the thinner side, and brazing.

In this way, a highly reliable wire-type dot matrix print head can be provided by using C1 wear-resistant carbide at a partial pressure at the tip and by using a highly resistant tungsten wire at the rear side.

As explained above, the present invention provides a highly reliable wire-type dot matrix print head by attaching a carbide wire to the tip of a highly resistant print wire.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a wire-type dot matrix printhead according to the present invention, and FIG. 2 is a diagram of a print wire. 1...Printed wire (tungsten), 1/
,,.・・・Carbide wire 1//・・・Brazing part, 2・
...armature.

Claims (1)

[Claims] A wire-type dot matrix print head characterized in that the tip of the wire is made of carbide wire and the other part is made of tungsten wire.