JPS5968262A - Wire dot printer - Google Patents

Abstract

PURPOSE:To attain to make allowances for the dimentional preciseness and the welding preciseness of an armature, by a method wherein the yoke mounted to a magnetic pole is formed into a ring shape and the opposed surface with the yoke of the armature is formed into an almost circular arc shape. CONSTITUTION:A notch is eliminated from a yoke 1 while the opposed surfaces of the yoke 1 and an armature are respectively formed into circular arc shapes. As mentioned above, because the yoke 1 is formed into the ring shape, the notch becomes unnecessary while the number of manufacturing processes are reduced and, therefore, dimensional preciseness is enhanced. Positional preciseness in the radius direction especially required in the connection of a leaf spring 3 and the armature 2 can be easily obtained by abutting both of them by a ring shaped jig or by inserting a sheet like spacer between said jig and the yoke 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire dot printer, and particularly to the structure of a yoke in a printer head thereof.

Generally, the yoke in such a printer head forms part of a magnetic circuit, and in this case, it is desirable that the gap between it and the movable iron piece (armature) be as narrow as possible, and that it have a shape with low magnetic resistance. The figure is a perspective view showing the structure of a head portion in a conventional wire dot printer, and FIG. 2 is a schematic diagram schematically showing a part of the magnetic circuit in FIG. 1.
1 is a yoke, 2 is an armature, 3 is a leaf spring, 4 is a printing wire, 5 is a notch, 6 is an iron core, and 7 is a coil.

That is, the yoke 1 is formed into a ring shape, and a plurality of notches 5 are provided in the circumferential direction. An armature 2 is fitted into each of the notches 5, and a printing wire 4 is welded or brazed to the tip of the armature 2. As is clear from FIG. 2, a magnetic path is formed by an electromagnet 1, a yoke 1, and an armature 2, each consisting of an iron core 6 and a coil 7. Since it is driven in the vertical direction in the figure, the printing wire 4 attached to the armature 2 moves, thereby printing is performed.
For example, 24 armatures 2 are provided in the circumferential direction of the yoke 1, and the print wires 4 fixed to these are arranged in two rows of 12 wires each at their tips to form a print head.

Like this fj? In order to reduce magnetic resistance in the wire dot printer that is manufactured, it is desirable that the gap between the yoke 1 and the armature 2 be as narrow as possible. , since the notches 5 have to be formed, the number of man-hours required for manufacturing them increases.0 In addition, the armature 2 must be correctly positioned on the leaf spring 3, and the assembly must be done taking into account the position with the yoke 1. The problem is that you have to do it.

The present invention has been made in view of the above points, and its purpose is to provide a wire dot printer that can reduce the number of man-hours for manufacturing a yoke, ease the dimensional accuracy and welding accuracy of an armature, and simplify assembly.

The feature is that the yoke is formed in a ring shape and the surface of the armature facing the yoke is formed in a substantially arc shape, thereby eliminating the need for cutting in the yoke as in the conventional art.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.

Note that FIG. 3 is a structural perspective view showing an embodiment of the present invention.

As is clear from the figure, this embodiment eliminates the notch from the yoke 1, and the yoke 1 and armature 2.
The feature is that the opposing surfaces are each shaped like an arc. Note that numerals 1 to 4 are the same as those shown in FIG. 1, and their operations are also the same, so a description thereof will be omitted.

As described above, according to the present invention, the following effects can be expected.

a) Since the yoke is ring-shaped, no incisions are required, thus reducing manufacturing man-hours and improving dimensional accuracy.

b)! When joining the spring and armature, a ring-shaped jig,
Alternatively, it can be easily obtained by inserting a sheet-like spacer between the yoke and the yoke and abutting against each other.

C) an assembly in which an armature and a leaf spring are joined;
When assembling the yoke, only the center positions need to be aligned with each other, and there may be some error in rotational direction, so assembly is easy.

d) Since the air gap between the yoke and the armature can be made extremely small compared to the conventional one, the magnetic resistance is reduced, and therefore the electromagnet or permanent abrasive stone used can be made inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the structure of a head portion in a conventional wire dot printer, Fig. 2 is a schematic diagram schematically showing a part of the magnetic circuit in Fig. 1, and Fig. 3 shows an embodiment of the present invention. FIG. Description of symbols 1... Yoke (yoke), 2... Armature (movable iron piece), 3...-- Leaf spring, 4...
...printing wire, 5...notch, 6...
... Iron core, 7 ... Coil agent Patent attorney Kiyoshi Matsuzaki

Claims (1)

[Claims] A predetermined number of armatures are arranged facing each other along the circumferential direction inside the ring of a ring-shaped yoke attached to the magnetic pole, and each of the armatures forms a magnetic path together with the yoke. 1. A wire dot printer that forms a desired character pattern by selectively electromagnetically driving printing wires, characterized in that a surface of each armature facing a yoke is formed in a substantially arc shape. .