JPH0434037Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The invention is used in the field of dot printers used in various printing devices, and specifically, the structure of the drive coil that operates the dot wire to print It is related to.

[Conventional technology]

In a dot printer, a movable piece is attracted by the excitation of a drive coil (solenoid), and a dot wire that is in contact with this movable piece is pushed to print.
The magnetic flux distribution in the axial direction in the drive coil is small at the ends due to magnetic flux leakage, and has a maximum value at the center. Therefore, in order to improve the electromagnetic conversion efficiency of the drive coil and increase the suction force, the suction part gap (hole) of the drive coil into which the suction iron piece provided on the movable piece is inserted should be placed near the center of the drive coil. It is desirable to provide a

However, as the length of the suction iron piece increases, the amount of movement in the radial direction of the head due to the operating movement of the movable piece increases, so the tip of the suction iron piece is prevented from coming into contact with the inner surface of the gap of the drive coil. It was necessary to provide an escape.

Therefore, conventionally, as seen in Japanese Utility Model Publication No. 10991/1983, the gap formed on the suction part side of the coil bobbin for fitting the suction iron piece was made into an oval shape that was elongated in the radial direction of the head. This prevented contact with the suction iron piece.

[Problem that the invention attempts to solve]

However, a drive coil using a bobbin as seen in the conventional example above can easily create the above-mentioned oval gap, and can be easily attached to a board or yoke, allowing automatic assembly of the drive coil. Although it has the advantage of making the bobbin thicker, it has the serious drawback that the electromagnetic conversion efficiency of the coil decreases due to the thickness of the bobbin. In order to solve this serious drawback, it has been considered to eliminate the use of the bobbin and use a direct-wound drive coil in which the coil is wound directly around the iron core, but this drive coil uses the bobbin. In contrast to the drive coil, there were problems such as it was difficult to create an oval gap, it was troublesome to attach it to the board or yoke, and it was difficult to automatically assemble it.

Therefore, the technical problem of the present invention is that it is possible to easily and accurately create an oblong (elliptical) gap into which the suction iron piece is inserted, and that the electromagnetic conversion efficiency of the coil is good, so that it can It is an object of the present invention to provide a drive coil for a dot printer which can be easily attached to a printer and can be easily assembled automatically.

[Means for solving problems]

The measures taken in the present invention to solve the above technical problems are as follows.

(1) On the front surface of a coil bobbin that has an insertion hole for the iron core in the center, a pair of projecting pieces each having an arcuate cross section are provided in parallel to protrude along the opposing edges of the insertion hole. Wrapping a coil around the space between the two protruding pieces.

(2) Furthermore, by abutting the tip side of the above-mentioned wound coil against the tips of the above-mentioned protruding pieces, and also winding it around a straight-wound shaft having an elliptical cross-section and having a structure to be pulled out after the coil winding layer, An oval hole is formed on the suction side of the layered coil.

However, here, the hole on the suction part side of the oval shaped coil means the opening that leads to the core insertion hole provided for fitting the suction iron piece attached to the movable piece that activates the printing operation of the dot wire. do.

[Effect]

The above means works as follows.

The reason for (1) above is that the coil bobbin is made with a so-called hollow structure in which a pair of arcuate upper protrusions are protruded in parallel, so the electromagnetism of the coil wound around these pair of protrusions is Conversion efficiency is not significantly affected by the thickness of the bobbin, and the reduction rate can be kept to a minimum to achieve excellent suction power.Furthermore, the conversion efficiency can be wound around a pair of protrusions with an arcuate cross section. The coil has an oval (long-shaped) cross section.
It is rolled into layers to form a shape. Since a coil bobbin is used to wind the coil, attachment to the board or yoke is easy, and automatic assembly is also possible.

According to the factor (2) above, the opening on the side of the coil suction part from which the straight-wound shaft is pulled out after the coil winding layer has an elliptical cross section and is a hole (void) into which the suction iron piece of the movable piece is inserted.
As a result, it is possible to form a so-called relief that prevents contact between the suction iron piece and the inner surface of the coil, but since this hole part has a direct winding structure with no bobbin at all, it exerts a strong suction action on the suction iron piece. Enables accurate dot wire operation.

As described above, the above-mentioned technical problem can be solved by the above-mentioned means, and the problems of the conventional technology can be solved.

〔Example〕

Hereinafter, a preferred embodiment of the drive coil for a dot printer according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a perspective view of a coil bobbin used in the present invention, and the coil bobbin, which is generally designated by the reference numeral 1, has a fixing plate 1a with an insertion hole 1b for the iron core in the front surface of the fixing plate 1a, which has an insertion hole 1b in the center. It has a structure in which a pair of upper and lower (or left and right) protrusions 1a and 2b, each having an arcuate cross-section, are protruded in parallel along the opposing edges of the container, and the whole is integrally formed using synthetic resin. ing. Further, 3a and 3b indicate terminals protruding from the back surface of the fixed plate 1a.

In FIGS. 2 to 5, reference numeral 4 denotes a coil wound around the coil bobbin 1. The coil 4, which is wound around the pair of upper and lower circular arc-shaped protrusions 2a and 2b, includes both protrusions 2a and 2b. Since both the left and right sides of 2b are cut out, the hollow portions are wound approximately linearly, and the whole is formed into an elliptical (elliptical) shape. Also, in Figures 2 and 4, 5
is a straight-wound shaft whose cross section is the same oval as that of the coil 4. When winding the coil 4, the straight-wound shaft 5 is butted against the tips of the projections 2a and 2b, and the straight-wound shaft 5 and A coil 4 is connected continuously to the partner of the protruding pieces 2a and 2b.
After winding, the straight winding shaft 5 is pulled out, and an oval hole 4 is formed in the suction part side (tip side) of the coil 4, as shown in FIG.
It is structured to form a.

FIG. 6 is a cross-sectional view of a dot printer incorporating a drive coil having the above structure, and inside a wire case 11 containing a plurality of dot wires 10, there is a wire case 11 to prevent each of these wires 10 from bending. Guides 12 . . . are formed at intervals, and a head guide 13 having guide holes 13 a . Further, each of the above dot wires 10 is urged to its original position by a coil spring 14. Reference numeral 15 indicates a yoke to which a plurality of iron cores 16 having a circular cross section are integrally attached, and the drive coil is inserted into the case body 17 with the iron cores 16 inserted into the insertion holes 1b. mounted on.

Further, reference numeral 18 denotes a movable piece (clapper) which operates using the root end 18a as a fulcrum, a leaf spring 19 is elastically contacted on the back surface, and the end of the dot wire 10 is abutted on the distal end surface. Furthermore, 18T is a suction iron piece with a cylindrical cross section that protrudes from the inner surface of the movable piece 18, and this iron piece 18T is located in an elliptical hole 4a opened on the suction part side of the drive coil 4. .

In FIG. 2, 1T and 5T represent the holding members for the coil bobbin 1 and the series winding shaft 5, and in FIG. 6, 17a is the lid plate of the case body, 20 is the platen, and 21 is the printing paper. , 22 indicates a printing ribbon.

Since the drive coil for a dot printer according to the present invention has the configuration as described above, this drive coil is attached to the iron core 16 of the dot printer as shown in FIG. If you position and energize, movable piece 1
8 is attracted and the dot wire 10 can be operated for printing. In addition, when the movable piece 18 performs a suction operation, since the hole 4a of the coil 4 is formed in an elliptical shape, the hole 4a is made deep and a long suction iron piece 18T is used to increase the electromagnetic conversion efficiency. Even if the suction iron piece 18T comes into contact with the inner surface of the coil 4, the movable piece 18 can be operated without any trouble.

〔effect〕

As described above, according to the drive coil for a dot printer according to the present invention, the dot wire can be operated accurately due to the excellent suction action, and printing can be performed accurately. ,
The elliptical hole of the coil into which the suction iron piece is inserted has a direct winding structure with no coil bobbin intervening, and the part of the coil bobbin where the coil is wound is also of a so-called hollow structure, minimizing the drop in electromagnetic conversion efficiency of the coil. In addition to being able to exert an excellent suction effect while minimizing
Because it uses a coil bobbin, it is easy to attach to the board or yoke, and it also enables automatic assembly, which can kill two birds with one stone.The structure is simple and easy to implement. Together with the point, it has a high practical value.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the coil bobbin used in the present invention, Fig. 2 is a cross-sectional view of the coil being wound, and Figs. 3 and 4 are the lines A-A and B-B in Fig. 2. 5 is a perspective view of a drive coil according to the present invention, and FIG. 6 is a sectional view of a dot printer incorporating the present invention. 1 is a coil bobbin, 1a is a fixing plate, 1b is an insertion hole, 2a and 2b are a pair of protrusions, 4 is a coil, 4a
is an oval hole formed on the suction part side, 16 is the iron core,
18 is a movable piece, and 18T is a suction iron piece.

Claims (1)

[Claims for Utility Model Registration] (1) A pair of protrusions each having an arcuate cross-section on the front surface of a coil bobbin having an insertion hole for the iron core in the center, along opposite edges of the insertion hole. protrudes in parallel, a coil is wound around the circumference between these protruding pieces, the coil is abutted against the tips of both protruding pieces, and the coil is pulled out after winding. A drive coil for a dot printer, characterized in that an oval hole is formed on the suction part side of the layered coil by wrapping the coil around the coil. (2) Claim 1 of the above-mentioned utility model registration, characterized in that the entire coil bobbin including the pair of protrusions is integrally molded using synthetic resin.
Drive coil for dot printers as described in Section 1. (3) A suction core of a movable piece that operates the dot wire is located in the hole on the suction part side of the elliptical coil, as described in claim 1 of the utility model registration claim. Drive coil for dot printers.