JPS58185273A - Dot printing head - Google Patents

Abstract

PURPOSE:To obtain a dot printing head having good attractive magnetic efficiency by using an easily fabricative structure in which cores constituting a magnetic circuit and exciting coils fixed to each core are arranged in the right- angled direction to the moving direction of a dot pin. CONSTITUTION:Magnetic flux of a permanent magnet 4 passed through a core 15a from the second yoke 15, flows in the projection 18a of an armature 18 through the space of the face A, and goes back to the permanent magnet 4 from the core 13a of the first yoke 13 through the face B of the attracting face. In such a magnetic circuit, the armature 18 attracts the core 13a of the first yoke at the face B and a plate spring 18 is held in a biased state. When, under the condition, the first exciting coil 14 and the second exciting coil 16 are electrically energized in the direction of erasing the magnetic flux of the permanent magnet, the attracting force between the armature 18 and the cores 13a and 15a is lost, the armature 18 is moved in a releasing manner by the elasticity of the plate spring 8, and printing is made by the dot pin 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Description of the technical field to which the invention pertains The present invention relates to a dot print head that prints desired characters, etc. by selectively driving a plurality of dot pins, and particularly to a dot print head that prints desired characters, etc. It is related to the head.

DESCRIPTION OF THE PRIOR ART FIGS. 1 and 2 are side sectional views and flat views of a conventional dot print head of this type. 1 is a circular pace plate having a plurality of radially arranged cores 2, 3 is an excitation coil arranged corresponding to each core 2 and constitutes an electromagnetic mechanism, and 4 is a pace gray/Q) on the tonneau. A fixed annular permanent magnet, 5 an annular yoke similarly fixed on the permanent magnet 4, 6 an armature fixed to one end of the dot pin 7 and converging radially near the center, 8 the above-mentioned A circular flat leaf spring fixing the armature 6; 9 an annular spacer that determines the amount of deflection of the leaf spring 8; 10 a flat yoke having a groove into which the armature 6 is loosely fitted; The mounting frames 12a and 12b are each wire guides.

Next, the operation of the dot print head constructed as described above will be explained. When the dot print head is not in the printing state, the magnetic flux of the permanent magnet 4 passes through the annular yoke 5 to the jaw 10.
A main magnetic path is formed that flows through the side wall to the armature 6 and then returns from the base plate 1 to the permanent magnet 4 through the core 2 of the electromagnetic mechanism, and the armature 6 is biased against the elasticity of the leaf spring 8 to form a main magnetic path. It is adsorbed to 2. At the same time, the dot pin 7 fixed to the armature 6 is also held in a retracted state from the wire guide 12a.

Next, when performing a printing operation, when the excitation coil 3 of the electromagnetic mechanism corresponding to the armature 6 to which the dot pin 7 to be printed is fixed is energized in a direction to cancel the magnetic flux of the permanent magnet 4, the armature 6 and the core 2, the armature 6 is released by the elasticity of the leaf spring 8, and the dot pin 7 is projected from the wire guide 12a to print. Furthermore, when the power supply is stopped at an appropriate timing before and after the end of printing, the main magnetic path of the permanent magnet is formed again, and the armature 6 is attracted to the core 2.

In the dot print head that prints in this way, there is only one main suction point, and a reverse suction force opposite to the suction force that attracts the leaf spring 8 is generated between the armature 6 and the yoke 10. This had the disadvantage that the suction efficiency deteriorated. Furthermore, since the cores 2 are either individually implanted in the base plate 1 or integrally molded, the cores are complicated, require many man-hours, and are expensive.

OBJECTS OF THE INVENTION It is, therefore, an object of the present invention to eliminate this drawback and to provide a dot print head with a structure that is easy to manufacture and assemble, and has good magnetic attraction efficiency.

The explanation will be given below according to the figures.

3 and 4 are a side sectional view and a plan view showing an embodiment according to the present invention. Here, 4 is an annular permanent magnet, 18
8 is an armature fixed to one end of the dotkin 7 and converging radially near the center, and 8 is the armature 18.
A flat circular plate spring 11 to which the frame is fixed is a mounting frame, and 12a and 12b are wire guides. or,
13 is a circular flat plate-shaped first yoke having the same number of dot pins as radially extending holes 13a in the center; 14 is a first excitation coil disposed corresponding to each core 13 & constituting an electromagnetic mechanism; Like the first yoke 13, a circular plate-shaped second yoke has a plurality of radial cores 15a, 16 is a second excitation coil corresponding to the second yoke 15, and 17 is a deflection amount of the leaf spring 8. This is an annular spacer.

Next, the operation of the first embodiment of the present invention will be explained.

FIG. 5 shows one mechanism when not in a printing state. The magnetic flux of the permanent magnet 4 flows from the second yoke (5) 15 through the core 15a to the protrusion 18a of the armature 18 across the gap on the A side in the figure, and further flows through the 8th attracting surface in the figure. 1 constitutes a magnetic circuit from the core 13a of the yoke 13 back to the permanent magnet 4. As a result, the protrusion 18a and the core 15a of the second yoke are attached to the armature 18.
A force that tries to oppose the surfaces acts, and a force that tries to attract the core 13a of the first yoke on the protrusion 18b acts on the eight surfaces. Due to this combined force, the armature 18 attracts the core 13a of the first yoke on the eight surfaces. However, the leaf spring 8 is held in a biased state. In this state, when the first excitation coil 14 and the second excitation coil 16 are energized in a direction that cancels the magnetic flux of the permanent magnet, the attractive force between the armature 18 and the cores 13a and 15a disappears, and the armature 18 becomes the leaf spring 8. Due to its elasticity, it is released and the dot kin 7 prints. This printing state is shown in FIG. Next, when the first excitation coil 14 and the second excitation coil 160 are de-energized at an appropriate timing before and after the end of the printing operation, the magnetic flux of the permanent magnet 4 flows to form a closed magnetic path, and on the A side, the armature 9 ( 6) The armature protrusion 18a and the core 15a of the second yoke are attracted in the direction in which they are about to face each other, and the armature protrusion 18b and the core 13a of the first yoke are attracted on the eighth side so that the gap is reduced. , it is biased against the elasticity of the leaf spring and returns to its initial state.

As explained above, in the first embodiment, when the armature 18 equipped with the dot bin 7 constitutes a magnetic circuit, two
Because it is attracted at only one location, it has the advantage of increasing the magnetic attraction efficiency. In addition, since the first yoke and the second yoke that form the magnetic path of the electromagnetic mechanism have a yoke portion and a core portion that are a single circular flat plate, they can be manufactured by punching, which has the advantage of facilitating manufacturing and assembly. Furthermore, the core 13 of the first yoke
Since the first excitation coil 14 and the second excitation coil fitted into the core 15a of the second yoke are excited in opposite directions in the excited state, there is an advantage that mutual interference due to generated magnetic flux is reduced.

In the first embodiment, the directions in which the magnetic flux flows on the attraction surfaces are set at right angles to each other, but substantially the same effect can be obtained even if the directions are set in the same direction as shown in FIGS. 7 and 8. In this case, since the first yoke 13 and the second yoke 15 can be identical, there is also the effect of cost reduction.

Therefore, according to the present invention, since the dot print head can be manufactured and assembled easily, it is possible to provide a dot print head that is small, lightweight, and inexpensive and has good magnetic attraction efficiency.

[Brief explanation of the drawing]

1 and 2 are a side sectional view and a plan view thereof of a conventional dot print head, FIGS. 3 and 4 are a side sectional view and a plan view thereof of an embodiment according to the present invention, and FIG. 5 is a side sectional view and a plan view thereof. , FIG. 6 is a side sectional view showing a rest state and a printing operation state of one embodiment of the present invention, and FIG. 7. FIG. 8 is a side sectional view showing a second embodiment of the invention. 4... Permanent magnet, 7... Dot bin, 8... Leaf spring, 11... Mounting frame, 12a, 12b...
Wire guide, 13...first yoke, 13a...core of first yoke, 14...first excitation coil, 15...
・Second yoke, 15a...Second yoke core, 16・
...Second excitation coil, 17...Surface, 18...
armature. Patent applicant: Oki Electric Industry Co., Ltd. (9) Figure 2

Claims (2)

[Claims] (1) A leaf spring is provided with an armature having a dot pin fixed to each of the tips of a plurality of tongues extending radially toward the center, and the tongues are biased by the magnetic force of a permanent magnet to the dot pins. In a spring-charged dot print head that prints by selectively energizing a correspondingly provided electromagnet to cancel the magnetic flux of the permanent magnet and use the strain energy accumulated in the leaf spring as printing energy, A circular first yoke having a core part extending radially toward the center, a first excitation coil fitted into the core part, and an annular permanent magnet sandwiched between the first yoke and the stacked structure. , a circular second yoke having a core portion extending radially toward the center, a second excitation coil fitted into the core portion of the second yoke, and each of the first and second yokes. The armature (1) has a U-shaped surface corresponding to each core part, and the cores forming the magnetic circuit and the excitation coil fixed to each core are arranged at right angles to the direction of movement of the dot pin. A dot print head characterized by: (2) A dot print head according to claim 1, characterized in that one print element has a structure in which an armature comprising a core and a dot pin constituting a magnetic circuit has two suction points.