JPH0337964Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement in a wire dot printing head.

(Prior Art) Conventionally, this type of print head is constructed as shown in FIGS. 7 to 11. In FIG. 7, 1 is a spring, 2 is an armature, 3 is a wire, and 9 is a lever, which constitute a printing element section. 4 is a permanent magnet, 5 is a side magnetic path plate, 6
is a coil, and these constitute the magnet section. Further, 8 is a yoke having a core portion 7 and to which the printing element portion and the magnet portion are attached. FIG. 8 shows one shape of the side magnetic path plate 5, which consists of a connected portion on the outer periphery and a comb-shaped portion protruding inward from the connected portion. As shown in FIG. 9, the armature 2 is displaceably inserted between the side magnetic path plates 5. for example,
The magnetic flux from the permanent magnet 4 flows to the core 7, the armature 2, and the side magnetic path plate 5 as shown by arrow A, but there is a gap between the armature 2 and the side magnetic path plate 5, and this It is desirable that the gap be narrower in terms of the magnetic circuit. FIG. 10 shows the yoke 8 portion, and a residial sheet 10 is usually provided between the armature 2 and the core portion 7 that constitutes its attraction surface to prevent magnetic stickiness. . In addition, other than residial sheets, there are also sheets in which the adsorption surface of the core 7 is coated with Teflon (registered trademark).

(Problem to be solved by the invention) As mentioned above, it is advantageous for the gap between the movable armature 2 and the side magnetic path plate 5 to be as narrow as possible from the standpoint of the magnetic circuit, but To ensure good performance, it is necessary to strictly control the assembly precision of each part. If the accuracy is low, as shown in FIG. 11, the armature 2 may lean too much to one side, resulting in a difference in the distances l ₁ and l ₂ between the left and right side magnetic path plates 5.
Therefore, an imbalance will occur in the power relationship. Furthermore, since the armature 2 does not face the core portion 7 correctly, there is a loss in terms of suction force, which results in variations in printing force. In an even more extreme case, the armature comes into contact with the side magnetic path plate, which impairs printing timing and poses a problem in trackability. Incidentally, if an attempt is made to provide a certain amount of air gap in order to eliminate such a problem, a problem arises in that the capacity of the permanent magnet 4 must be increased accordingly.

The present invention solves the above-mentioned problems of the conventional technology all at once.The gap between the armature and the side magnetic path plate is narrowed, and even if the assembly accuracy is slightly reduced, the printing allows the armature to move smoothly. It provides a head.

(Means for Solving the Problems) In the present invention, a residial sheet is interposed between the movable armature and its attraction surface, and also between the armature and the side magnetic path plate.

(Function) By providing a reciprocal sheet between the armature and the side magnetic path plate, even if the assembly accuracy is slightly degraded and the armature slides a little on the reciprocal sheet, it will not stick to the side magnetic path plate. Can make smooth movements.

(Example) Hereinafter, an example will be described in detail based on the drawings. 1 and 2 show an embodiment of the present invention, in which reference numeral 11 is a residial sheet, which includes an annular flat sheet portion 11a and a plurality of folds vertically rising from the flat sheet portion. 11b. When assembled as shown in FIG. 1, the flat sheet portion 11a is located between the armature 2 and the core 7, and the pleated portion 11b is located between the armature 2 and the side magnetic path plate 5.

In this embodiment configured in this way, if the width of the armature 2 and the spacing between the comb teeth of the side magnetic path plate 5 are controlled with a certain degree of accuracy, it is possible to sufficiently correct some deviations during assembly. In addition, even if the left and right sides are not balanced, the armature can move extremely smoothly due to the presence of the seat.

3 and 4 show another embodiment of the present invention, in which the residial sheet 12 is constructed by folding the sheet into a large zigzag shape. It goes without saying that this embodiment also has the same effects as the embodiment shown in FIG.

FIGS. 5 and 6 show a modification of FIGS. 1 and 2, in which the folds of the residial sheet are extended inward. With such a configuration, it is possible to prevent the root portions of the wires 3 from coming into direct sliding contact with each other.

Note that as the material for the residial sheet, a sheet made of polyester or the like can be used, but a sheet made of resin may also be used. Further, instead of forming the sheet by folding it, the necessary notches may be made in the annular flat sheet, and one end of the sheet piece may be inserted into the notch to stand vertically to form the pleats. Note that functional satisfaction can be achieved by applying Teflon coating to the adsorption surface of the core portion and the side surface of the side magnetic path plate instead of the residial sheet.

In the embodiment, a wire dot head with an open type configuration, that is, a wire dot head of the type in which the magnetic flux of the permanent magnet is canceled by energizing the coil during printing to release the restraint of the armature, has been described, but the present invention is not limited to this. First, if a print head is equipped with a side magnetic path plate to form a magnetic circuit, and has a movable armature and a core that serves as an adsorption surface, a residial sheet is always used to prevent magnetic stickiness. The present invention can be applied to heads.

(Effects of the invention) As explained above, according to the invention, by interposing the residial sheet between the movable armature and the core part and between the armature and the side magnetic path plate, It becomes possible to set the air gap narrowly, which is very advantageous in terms of the magnetic circuit. Further, even if the assembly accuracy is slightly degraded and the armature comes into contact with the residial sheet to some extent, the armature can still move smoothly.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a perspective view of the same residial sheet, Fig. 3 is a block diagram of another embodiment of the present invention, and Fig. 4 is a perspective view of the same residial sheet. FIG. 5 is a perspective view of the serial sheet, FIG. 5 is a configuration diagram of a modified embodiment of FIG. 1, FIG. 6 is a perspective view of the same registra sheet, FIG. is a plan view of the side magnetic path plate, FIG. 9 is a diagram showing the flow of magnetic flux, FIG. 10 is a diagram showing the yoke part and the conventional residial sheet, and FIG. 11 is a diagram showing the conventional residial sheet. The incorporated armature,
It is a figure which shows the relationship between a core part and a side magnetic path plate. 1... Spring, 2... Armature, 3... Wire, 4... Permanent magnet, 5... Side magnetic path plate, 6... Coil, 7... Core section, 8... Yoke, 9... Lever, 11, 12, 13...Residial sheet.

Claims (1)

[Scope of utility model registration request] Printing comprising a printing element section including a spring, an armature and a wire, a magnet section including a permanent magnet, a side magnetic path plate and a coil, and a yoke including a core section and mounting the printing element section and the magnet section. A printing head characterized in that, in the head, residial sheets are interposed between the armature and a core portion constituting its suction surface, and between the armature and a side magnetic path plate.