JPS60124259A - Wire dot printer - Google Patents

Abstract

PURPOSE:To enable the miniaturization of an electromagnet and ultimately a print head with an increase in the attraction for the electromagnet by providing a dent on the core of the electromagnet while protrusion is provided on an armature so as to be fitted thereinto contactlessly. CONSTITUTION:A protrusion 21 like a small cylinder is provided on the surface to be attracted to a fixed core 6 of an armature 8. On the other hand, a dent 22 is formed on the surface to be attracted to the armature 8 or the fixed core 6 so as to have the protrusion 21 fitted thereinto. The outer surface of the protrusion 21 and the inner surface of the dent 22 are kept from contacting each other whether the armature 8 is attracted to the fixed core 6 or not but it is preferably to minimize the interval therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a wire dot printer in which the driving force of an electromagnet to a dot wire is strengthened.

[Technical background of the invention]

Figure 1 shows the print head drive section of a wire dot printer.A cylindrical yoke 3 with a bottom is connected to the drive section case 1 via a terminal @2, and a cylindrical nose section is located at the center of the bolt case I. 4 extends in the opposite direction to the yoke 3.

Inside the yoke 3, a plurality of electromagnets 5 (only one is shown) are installed at equal intervals in the circumferential direction. The electromagnet 5 above
is composed of a fixed iron core 6 fixed to the inner bottom surface of the yoke 3 and a secondary coil 7 wound around the fixed iron core 6.

Furthermore, the base end of an armature 8 corresponding to each electromagnet 5 is arranged at the open end of the yoke 3. These amateurs 8 are positioned by an amateur guide plate 9,
Each tip is located near the center of the yoke 3. Maku,
A circular hole is provided at the center of the bottom of the yoke 3, and a wire guide plate 10 is attached so as to close this circular hole.

The wire guide plate IO is provided with a wire insertion hole ZZ corresponding to each electromagnet 5, and a dot wire Z2 is inserted into each insertion hole 11.

The tip of each dot wire 12 reaches the tip of the nose portion 4 and is brought into contact with the armature 8 by a platen (not shown) K facing 13. Therefore, the coil spring 13 has a function as a return spring that separates the armature 8 from the identification core 6 together with the dot wire 2.

On the other hand, a cap 14 is placed on the amateur guide 9, and a holding member 15 made of a leaf spring is placed on top of the cap 14, and the yoke 3, the amateur guide 9, and the cap 14 are integrated by this holding member 15. ing.

Further, an armature pressing spring 16 made of a plate spring is inserted between the armature guide 9 and the cap 14, and one end of each armature 8 is held pressed against the open end of the yoke 3 by this pressing spring 16Vc.

Further, a positioning pin 12 is protruded from the center of the inner surface of the cap 14, and a stopper 18 made of an annular plate is attached to the pin I2.

This stopper I8 brings the tip of each armature 8 into contact with the dot wire 12 from the opposite side to receive the reaction force of the coil spring Z30.

In the above configuration, when the coil 7 of the electromagnet 5 is energized, a magnetic path is formed by the path of the fixed iron core 6, the yoke 3, and the armature 8, and the armature 8 is attracted to the fixed iron core 6 and rotates. Therefore, the tip of the armature 8 presses the dot wire 20, and the tip of the dot wire 20 protrudes from the tip of the nose portion 4 to print dots on the printing paper wound around the platen. Further, when the current to the coil 7 is cut off, the dot wire 12 and the armature 8 are returned to their original positions by the coil spring 13.

[Problems with background technology]

The turning force of the armature 8 is generated by the magnetic flux passing through the main magnetic path A passing through the armature 8, as shown by the dotted line in FIG. However, in reality, magnetic path B does not go through Amateur 8.
Also, the so-called leakage magnetic flux passing through such magnetic path B does not contribute to rotating the armature 8.

First, in order to downsize the printer, it is desirable to make the electromagnet 5 as small as possible, and in order to downsize the electromagnet 5, it is necessary to reduce leakage magnetic flux as much as possible.

Furthermore, bringing a plurality of electromagnets 5 closer together is also an extremely important issue in reducing the size of the print head drive unit, but on the other hand, magnetic interference between adjacent electromagnets 50 increases as they approach each other. [Object of the Invention] The present invention was made based on the above circumstances, and its purpose is to reduce the leakage magnet of the electromagnet that drives the dot wire, and to reduce the magnetic leakage between the electromagnets that are in contact with each other. The aim is to reduce interference, strengthen the rotational force of the armature, and downsize the electromagnet and, by extension, the wire dot printer.

[Summary of the invention]

In order to achieve the above object, the wire dot printer of the present invention is characterized in that a protrusion made of a magnetic material is provided on the attracting surface of the armature, and a fixed iron gate made of a piezoelectric magnet is provided.

With this configuration, even when the armature is apart from the fixed iron core, the protrusion can be inserted shallowly into the recess, and the distance between the protrusion and the fixed iron core can be kept narrow. Since the armature and the protrusion are integrated, the magnetic flux resistance decreases in the same way as when the armature is brought closer to the fixed iron core, and the main magnetic path A that passes through the armature and the protrusion decreases.
The magnetic flux passing through increases. Therefore, the magnetic flux passing through the magnetic path B that does not go through the armature and the magnetic interference between adjacent electromagnets are reduced, the rotational force of the armature is strengthened, and the electric field, the magnet, the print head drive unit, and the printer are made smaller. can be made smaller.

[Embodiments of the invention]

2 and 3 show an embodiment of the present invention,
The same parts as in Fig. 1 are given the same reference numerals and detailed explanations &
j omitted.

The armature 8 is provided corresponding to each of the plurality of electromagnets 5, and a small cylindrical projection 21 is provided on the surface of the armature 8 to be attracted to the fixed iron core 6. On the other hand, a recess 22 into which the protrusion 2Z is inserted is formed on the attraction surface of the fixed core 6 to the armature 8. Note that the outer surface of the protrusion 21 and the inner surface of the recess 22 are different from each other when the armature 8 is not attracted to the fixed iron core 6 (
Although it is assumed that they do not contact each other when they are attracted (FIG. 2) or when they are attracted (FIG. 3), it is desirable to keep the distance between them as small as possible.

Therefore, although the distance between the end surface of the protrusion 21 and the bottom surface of the recess 22 changes with the rotation of the armature 8, the distance between the outer peripheral surface of the projection 2z and the inner peripheral surface of the recess 22 has little to do with the rotation of the armature 180. Since the distance is approximately constant, the distance between the protrusion 2Z and the inner circumferential surface of the recess 22 can be kept small at all times.

Therefore, when the armature 8 is separated from the fixed iron core 6 as shown in FIG. 2, when the coil 7 of the electromagnet 5 is energized,
As shown by the dotted line in the figure, a magnetic path is formed by the fixed iron core 6, yoke 3, armature 8, and projection 21. As described above, the magnetic flux passing through the magnetic path via the armature 8 generates an attractive force that attracts the armature 8, that is, a rotating force of the armature 8, and the armature 8 rotates as shown in Fig. 3 and attracts the fixed iron core 6. be done. At this time, leakage magnetic flux is also generated that does not pass through the armature 8 and does not contribute to the generation of attractive force to the armature 8, but since the magnetic flux resistance between the protrusion 21 and the fixed iron core 6 is reduced, the leakage magnetic flux is significantly reduced. In addition, magnetic interference between adjacent electromagnets 5 is significantly reduced,
Correspondingly, the turning force of the amateur 8 is strengthened.

Therefore, it is possible to make the electromagnet 5 smaller, the print head driving section by bringing the electromagnets 5 closer together, and the printer itself to be smaller.

〔Effect of the invention〕

As detailed above, according to the present invention, the leakage magnetic flux of the electromagnet that drives the dot wire is reduced, and the magnetic interference between adjacent electromagnets is reduced, thereby increasing the turning force of the armature and increasing the printing force by the dot wire. It is possible to improve the print quality. Further, it is possible to reduce the size of the electromagnet and, in turn, to reduce the size of the wire dot printer.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a print head drive unit showing a conventional example.
2 and 3 show an embodiment of the present invention,
FIG. 2 is a partial cross-sectional view showing the print head drive section in a non-energized state, and FIG. 3 is a partial cross-sectional view showing the print head drive section in a power-on state. 5... Electromagnet, 8... Armature, 12... Dot wire, 2I... Protrusion, 22... Recess. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Commissioner of the Japan Patent Office Kazuo Wakasugi 1. Indication of the case Patent application No. 1983-232283 2. Name of the invention Wire Draton 0 Linta 3. Amends. Relationship with the patent applicant (356-) Tokyo Electric Co., Ltd. 4, agent 6, amended description, complete text 7, revised contents of the description (1 content unchanged)

Claims (1)

[Claims] In a wire dot printer that attracts and drives an armature using an electromagnet and prints dots using a dot wire connected to the armature, a protrusion made of a magnetic material is provided on the attracting surface of the armature, and a protrusion made of a magnetic material is provided on the attracting surface of the fixed iron core of the electromagnet. A wire dot printer characterized in that a recess is provided into which the projection is inserted without contact.