JPH0243633B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a print head for a dot printer, and more particularly, the present invention relates to a print head for a dot printer, and in particular, a hinge part of an armature provided with a dot printing element (for example, a wire) at the tip part is swung on a hinge part of a base. The present invention provides an improved structure around the armature in a print head of the mounted construction type.

(2) Background of the Technology In the above-mentioned type of print head, the armature is basically only placed on the base hinge, so a side guide is required to restrict the direction of its swing. Additionally, as the armature swings, a gap is created between the armature hinge section and the base hinge section, which inevitably results in low magnetic efficiency.Therefore, generally, a side magnetic path is provided on the side of the armature to improve magnetic efficiency. A structure that enhances this is adopted. However, the conventional structure has problems as described below, and countermeasures are desired.

(3) Prior Art and Problems In the conventional structure, the side guide for the armature and the side magnetic path are each formed as separate parts and are individually attached to the base or the like. Therefore, there are problems in that the number of parts is large, and the number of man-hours for manufacturing and assembling parts is large, resulting in high costs, and the structure of the print head is also complicated, which hinders miniaturization.

(4) Purpose of the Invention In view of the drawbacks of the above-mentioned prior art, the present invention provides a print head of the above-mentioned type that has a small number of parts and
Therefore, it is an object of the present invention to provide an improved structure in which parts manufacturing and assembly are simple and costs can be reduced, and the print head structure can be simplified and downsized.

(4) Structure of the Invention In order to achieve the above object, the print head of the present invention includes a printing element 6 fixed at the tip thereof, an armature 5 which is a rigid and magnetic body, and a device for applying printing force to the armature 5. a compression spring 9, a permanent magnet 3 for attracting the armature 5 to the reset position against the compression spring 9, and an electromagnet capable of canceling the attraction force of the permanent magnet 3 to release the armature 5. 8, 2, a magnetic path passing through the armature 5, the electromagnets 8, 2, and the permanent magnet 3, an armature support portion 4 that swingably supports the armature 5, and the armature support portion 4.
a magnetic plate 7 provided above, the magnetic plate 7 having a gap 11 into which the other end of the armature 5 can swing and be inserted without any play;
It is characterized by having a protrusion 10 extending laterally of the armature 5.

(5) Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic structure of an embodiment of a print head according to the present invention. This printhead is a so-called open-ended circular array multi-dot wire printhead. In the figure, reference numeral 1 indicates a circular base, on which a plurality of cores 2 are arranged in an annular manner and integrally formed, and the same number of permanent magnets 3 and armature support portions 4 are also arranged in an annular shape. They are arranged and fixed with adhesive. Further, reference numeral 5 indicates an armature, and a plurality of armatures are arranged radially with their tips directed toward the center of the base 1. A dot printing wire 6 is provided at the tip of the armature 5, and the rear end of the armature 5 is swingably mounted on the armature support 4. Further, reference numeral 7 indicates a magnetic plate, which provides a side guide and a side magnetic path for the armature 5, as will be described later. Furthermore, each core 2 is provided with a coil 8, and each armature 5 is connected with a compression spring 9. The spring 9 always applies a force in the direction of arrow A to the armature 5. Although not shown, the armature 5 is usually held by an elastic O-ring, for example, to prevent it from shifting in the longitudinal direction.

In a normal non-printing state, the armature 5 is attracted to the core 2 by the magnetic force of the permanent magnet 3 against the action of the spring 9. When the coil 8 corresponding to the required armature 5 is energized during printing, the magnetic force of the permanent magnet 3 is canceled out, and the armature 5 is released in the direction of arrow A by the action of the spring 9 (indicated by a virtual line 5'). The wire 6 strikes an ink ribbon and paper (not shown) to perform dot printing.

The feature of the present invention in the print head described above lies in the structure of the magnetic plate 7. That is, as clearly shown in FIG. 2, the magnetic plate 7 has a large number of comb-shaped protrusions 10 on the inside, and gaps 11 between these protrusions 10
Armature 5 inside (only two are shown in Figure 2)
are now being placed. The root part 10a of the protrusion 10 has a width dimension that allows the rear end of the armature 5 to be pivoted and inserted without any play.
This root portion 10a therefore functions as a lateral guide for the armature 5. On the other hand, since the protrusion 10 extends close to the side of the armature 5,
It also functions as a side magnetic path with good magnetic efficiency.
Note that the hole 12 of the magnetic plate 7 is a hole for attachment to the base 1.

That is, the magnetic plate 7 is a single component that provides both side guides and side magnetic paths for a large number of armatures 5. Therefore, the number of parts can be reduced compared to the conventional structure, making it easier to manufacture and assemble parts. It is possible to reduce man-hours and reduce costs, and
Simplification and miniaturization of the printhead structure are achieved.

(7) Effects of the Invention As described above, according to the present invention, it is possible to realize a print head that has a small number of parts, has a low manufacturing cost, is inexpensive, has a simple structure, and is compact.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of one embodiment of a print head according to the present invention, and FIG. 2 is a plan view of a part of the armature and magnetic plate. 1...Base, 2...Core, 3...Permanent magnet,
4... Armature support part, 5... Armature, 6... Dot printing wire, 7... Magnetic plate, 8
...Coil, 9...Compression spring, 10...Protrusion of magnetic plate.

Claims (1)

[Claims] 1 An armature 5 having a printing element 6 fixedly attached to its tip and being a rigid and magnetic body;
a compression spring 9 for applying a printing force to the printer; a permanent magnet 3 for attracting the armature 5 to the reset position against the compression spring 9; Electromagnets 8, 2 that can be released, a magnetic path passing through the armature 5, the electromagnets 8, 2, and the permanent magnet 3, an armature support 4 that swingably supports the armature 5, and the armature support 4, the magnetic plate 7 has a space 11 into which the other end of the armature 5 can swing and be inserted without any play, and has a space 11 on the side of the armature 5. A printhead characterized in that it has an extending protrusion 10.