JPS60183169A - Magnet device for dot printer - Google Patents

Abstract

PURPOSE:To arrange so that a printing head may be miniaturized by positioning printing wire almost in parallel with the leg of a yoke and extending the wire on an opposite side to an auxiliary yoke. CONSTITUTION:A permanent magnet 4 is inserted halfway through a U-shaped yoke 1 of magnetic material and also an auxiliary yoke 5 with one end face bonded to the mentioned magnet and the other end face opposed at certain space to the end face 3a of the other leg is arranged. In addition, a coil 8 for cancelling the magnetic suction force of the permanent magnet 4 is wound around a yoke leg 3 and a release spring 9 is fixed at the base end of a yoke 1. At the tip of the release spring, is fastened an armature 10 to be sucked to the auxiliary yoke 5 side at the time of coil demagnetization. Following the action of the armature, a printing wire 14 is driven by an arm 15. This printing wire 14, positioned almost in parallel with the yoke led 3 and extending on an opposite side to the auxiliary yoke 5, allows the printing head to be miniaturized.

Description

[Detailed description of the invention] [Technical field] The present invention relates to an electromagnetic device for a dot printer.

[Background Art] An electromagnetic device for a dot printer consists of a C-shaped cork A, a permanent magnet B inserted in the middle of a yoke A (including the end of the a-way), and a permanent magnet as shown in the figure. Coil C' is wound around yoke A in order to offset the magnetic attraction force of B, the base end is fixed to one end of the yoke via a release spring D, and the driving end is connected to the printing wire F via arm E. Fix the proximal end,
The middle part faces the (one end) of coke A and receives its magnetic attraction force, and when coil C is demagnetized, it is attracted to the other end of yoke A, producing a spring biasing force, and when coil C is energized,
This spring biasing force is generally released to drive the printing wire F, and a plurality of sets (for example, 9 sets) of this electromagnetic device are arranged in parallel to form the print head of a dot printer. , each set of electromagnetic devices biases Amachia G, which has an inherent spring biasing force, with permanent magnet B, and cancels the magnetic attraction force of permanent magnet B by excitation of coil C corresponding to the printed area, and creates Amathia G. Printing is performed by releasing the biasing force of the spring and driving the printing wire F. H is an auxiliary yoke, ■ is a wire guide, J is an ink ribbon, K is paper, and L is a platen.

In such an electromagnetic device, the amachia G that was attracted to the other end of the yoke A is released by the excitation of the coil C, and at that time, the printing wire F protrudes and the ink ribbon J on the platen L is released.
When the print head P of a do-no-do printer is constructed, the length of the print wire F in the extending direction is the length of the print wire F and the length to the yoke, as shown in the second figure. The added amount is the minimum required. Furthermore, a yoke A is attached to the print head P in which this electromagnetic device is installed in parallel.
The space S surrounded by is a dead space. Therefore, such an electromagnetic device has been an obstacle to the desire to downsize the print head P.

[Object of the Invention] The present invention has been made in view of the above points, and an object thereof is to provide an electromagnetic device for a dot printer that can reduce the size of the print head.

[Disclosure of the invention] (Example) The present invention will be described below as an example in Figures 3 and 4.
This will be explained based on the diagram.

In the figure, reference numeral 1.1 denotes a yoke, which is made of a magnetic material and has two legs 2.3 facing each other and formed in a U-shape. A permanent magnet 4 is fixed to the end face of one leg 2. This permanent magnet 4 may be provided at any location on the coke 1 (as long as it is understood that it is inserted in the middle of the yoke 1 including the end face of one of the legs 2. 5 is an auxiliary yoke; One end surface 6 is joined to one leg 2 (in this case, the upper end surface of the permanent magnet 4) of the permanent magnet 4, and the other end surface 7 faces the other leg end surface 3a with a predetermined gap g therebetween. 8 is a coil, permanent magnet 4
The cork 1 is wrapped around the other leg 3 of the cork 1 in order to offset the magnetic attraction of the cork 1. 9 is a release spring, and yoke 1 (in this case,
The base end is fixed to the joint between the auxiliary yoke 5 and the permanent magnet 4), and the other end extends toward the other leg 3.

Reference numeral 10 denotes an amadea, which is made of a magnetic material and has a thickness sufficiently smaller than the width of the gap 8 mentioned above, is located within the gap g, and when the coil 8 is demagnetized, its upper surface 11 is attracted to the other end surface 7 of the auxiliary yoke 5. Its underside 12 is fixed to the free end of the release spring 9 so that it can be released. In other words, without considering the magnetic attraction force of the permanent magnet 4, the gap between the other end surface 7 of the auxiliary yoke 5 and the upper surface 11 of the amatia 10 is the same as that of the other leg end surface 3a.
and the lower surface 12 of the amatia 10. In addition, the magnetic efficiency of the magnetic circuit can be improved by protruding from the other leg end surface 3a of the yoke 1 a magnetic pole piece 3b shaped to grip the amachia 1o.

Reference numeral 13 denotes an arm, one end of which is fixed to the amachia 1o and follows it, and the printing wire 14 is positioned approximately parallel to the leg portion 2.3 of the yoke 1 and extends on the opposite side from the auxiliary yoke 5. A printing wire 14 is fixed to the other end. Note that this arm 13 may be formed integrally with the amatia 10.

Therefore, when the coil 8 is demagnetized, due to the magnetic attraction force generated by the magnetic flux X of the permanent magnet 4 flowing from the state shown in the third figure,
The amachia 1o is attracted to the other end surface 7 of the auxiliary yoke 5 against the spring force of the release spring 9, and this generates a spring biasing force.On the other hand, when the coil 8 is excited, a magnetic flux flows in the opposite direction to the magnetic flux X. This attraction is released by canceling out the magnetic attraction force of the permanent magnet 4, and as a result, the above-mentioned spring biasing force of the amachia 10 is also released and the state shown in FIG. It operates using point R of 9 as a fulcrum, and prints by driving the printing wire 14.

When a plurality of sets (for example, nine sets) of these electromagnetic devices are arranged in parallel to form the print head P of a dot printer, the length of the print wire 14 in the extending direction is as shown in the fifth figure.
It is significantly shorter than the conventional one. In other words, whereas the space surrounded by the yoke 1 was conventionally a dead space, in this case the space surrounded by the printing wire 1 is a dead space.
4 is disposed, and as a result, the print head P can be made smaller by approximately the length of the yoke 1.

[Effects of the Invention] As described above, the electromagnet device for a dot printer of the present invention includes a yoke formed in a U-shape, a permanent magnet inserted in the middle of the yoke, and a permanent magnet attached to the end face of one leg of the yoke. an auxiliary yoke whose one end surface is joined and whose other end surface faces the end surface of the other leg with a predetermined gap therebetween; a release spring having a proximal end fixed to the yoke; and an amatia fixed to the free end of the release spring so as to be located in the gap and attracted to the other end surface of the auxiliary cork when the coil is demagnetized. , an arm that is provided to follow the amatia and drive a printing wire, and the printing wire is located approximately parallel to the leg of the cork and extends on the opposite side from the auxiliary yoke. Therefore, the print head can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an electromagnetic device of a conventional dot printer, FIG. 2 is a side view including a partial cross section of a print head constructed using the electromagnetic device, and FIG. 3 is a vertical sectional view showing an embodiment of the present invention. , FIG. 4 is a sectional view of a main part thereof, and FIG. 5 is a side view including a partial cross section of a print head constructed thereby. 1-Yoke, 4...-Permanent magnet, 5--Auxiliary yoke,
8--coil, 9--release spring, 10-amathia, 1
3-arm, 14-printing wire. Patent applicant: Matsushita Electric Works Co., Ltd. Patent attorney Toshikuro Takemitsu (two idiots) Figure 3

Claims (1)

[Claims] (11) A yoke formed in a U-shape, a permanent magnet inserted in the middle of the yoke, one end face joined to the end face of one leg of the yoke, and the other end face joined to the end face of the other leg. an auxiliary yoke facing the yoke with a predetermined gap therebetween; a coil wound around the other leg of the yoke to offset the magnetic attraction force of the permanent magnet; and a release spring having a base end fixed to the yoke. an amatia located within the gap and fixed to the free end of the release spring so as to be attracted to the other end surface of the auxiliary yoke when the coil is demagnetized; It consists of an arm that
the printing wire is located substantially parallel to the leg of the yoke;
Moreover, the electromagnet device for a dot printer is characterized in that the electromagnet device extends on the opposite side from the auxiliary yoke.