JPH06183038A - Dot printer head - Google Patents

Abstract

PURPOSE:To prevent abrasion of remanence preventive film due to undulation of an armature. CONSTITUTION:A plurality of armatures 8 are opposed to the attraction plane 17a of a core 17 and the end face 18b of a yoke 18 through remanence preventive films while a synthetic resin ring 28 is provided fixedly on the same plane as the end face 18b of the yoke 18 along the peripheral direction of the annular yoke 18 and a plurality of fulcrum parts 28b for supporting the armature 8 on a line crossing perpendicularly with the longitudinal direction thereof such that the armature 8 can undulate freely are formed closely to the periphery 18c of the yoke 18. Furthermore, a curved plane 28c is formed on the top of the fulcrum part 28b in order to apply load uniformly to a film over the entire region corresponding to the length of the fulcrum part 28b thus reducing load per unit area and enhancing durability of film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot printer head.

[0002]

2. Description of the Related Art First, a conventional example is shown in FIGS. 1
Is a mounting member fixed to the carrier of the printer, and 2 is a container-like housing having one end opening. An armature guide 4 that abuts the bottom surface of the housing 2 is integrally formed at one end of the needle guide 3 protruding from the bottom of the housing 2. The armature guide 4 is formed with a plurality of guide pins 5 and projecting pieces (not shown) for guiding both sides of the armature 8, and an armature spring 6 and a fulcrum pressing spring 7 are provided inside the guide pin 5. And is arranged and held on the outside. A plurality of needles 9 fixed to the inner end of the armature 8 are slidably held by a plurality of guide tips 10 fixed to the needle guide 3. Further, a plurality of stopper receivers 11 are fitted in the armature guide 4.
Then, while inserting the needle 9 into the guide tip 10, the armature 8 is inserted into the guide pin 5, and the housing 2
Bottom surface, stopper receiver 11, film 12 formed of a non-magnetic material, spacer 12a, stopper 1
An armature block 15 is formed by laminating 3 and 3 and connecting them with a screw 14.

Next, a plurality of cores 17 each having a coil 16 mounted thereon are integrally formed with a yoke 18.
The yoke block 20 is formed by fixing the substrate 19 to which the coil 16 is connected to the back surface of the yoke 18. A connector 21 connected to an external circuit is fixed to the board 19. Then, the screw 22 passed through the mounting member 1, the housing 2, and the stopper receiver 11 is screwed into the yoke 18 to complete the dot printer head. In this state, the inner surface of the armature 8 faces the suction surface 17a of the core 17, and is supported by the fulcrum portion 18a formed on the yoke 18 by the pressure of the fulcrum pressing spring 7 via the film 12. . The fulcrum portion 18a is an annular edge formed on the yoke 18.

Next, the operation will be described. By selectively exciting the coil 16, the armature 8 is attracted to the attraction surface 17a of the core 17 and rotated about the fulcrum portion 18a, and the needle 9 is pressed against the sheet 25 on the platen 24 via the ink ribbon. Then, the printing is performed. When the coil 16 is de-energized, the armature 8 is returned by the urging force of the armature spring 6 and the stopper 13 determines the return position.

Here, since the film 12 is provided between the attraction surface 17a of the core 17 and the end surface of the yoke 18, and between the fulcrum portion 18a and the armature 8 to reduce the residual magnetism, the coil 12 is provided. When the power supply to 16 is cut off, the armature 8 is quickly separated from the suction surface 17a to prepare for the next operation. This enables high-speed printing.

[0006]

Although the armature 8 is opposed to the core 17 and the yoke 18 with a flat surface,
As shown in FIG. 6, the undulating motion of the armature 8 forms an indentation 26 corresponding to the suction surface 17a of the core 17 and an indentation 27 corresponding to the yoke 18 on the inner surface of the film 12. On the other hand, the fulcrum portion 18a of the yoke 18 has an arc-shaped edge. Therefore, in this example, the film 12 is
Since an unbalanced load is locally applied to the fulcrum portion 18a, not to the entire area, it is likely to be partially worn. The wear range expands from the outer side to the inner side in accordance with the number of times of printing, and also in the radial direction, and eventually a hole is opened to eliminate the air gap between the fulcrum portion 18a and the armature 8. As a result,
The return operation of the armature 8 when the power supply to the coil 16 is cut off is delayed, and the printing operation is hindered.

Therefore, by forming the yoke 18 into a polygonal shape, the fulcrum portion 18 is provided on each side that is a straight line.
By forming a and supporting the armature 8 through the film 12 by the linear fulcrum portion 18a, it is considered that the film 12 is evenly loaded to prevent the film 12 from being worn, but the number of processing steps is reduced. Therefore, the yoke 18 needs to be integrally formed with the plurality of cores 17. Therefore, there is a method of forming with a sintered alloy,
It is not practical because the high dimensional accuracy required for a dot printer head cannot be obtained.

Further, there is a method of lubricating the fulcrum portion 18a in order to prevent abrasion of the film 12, but it is difficult to locally lubricate and the lubricating oil spreads around. Since the lubricating oil has a high viscosity at a low temperature and resists the operation of the armature 8, it is not preferable as a solution for preventing abrasion of the film 12.

[0009]

SUMMARY OF THE INVENTION The present invention comprises a plurality of cores magnetically coupled to an annular yoke and arranged along the circumferential direction of the yoke, each holding a coil.
A plurality of armatures arranged radially in opposition to the respective suction surfaces of these cores and the end surface of the yoke via a film for preventing residual magnetism, and a plurality of armatures slidably held by a needle guide of the armatures. In a dot printer head having a plurality of needles connected to the tip, driving the armature by energizing the coil to cause the tip of the needle to collide with a platen, a dot made of synthetic resin along the circumferential direction of the yoke. A ring is fixedly provided, and a plurality of fulcrum portions for supporting the armature on a straight line orthogonal to the longitudinal direction of the yoke on the same plane as the end surface of the yoke are formed close to the peripheral edge of the yoke on the ring. A curved surface was formed on the top of the fulcrum.

[0010]

Since the fulcrum portion is a straight line and the curved surface is formed on the top of the fulcrum portion, the film is evenly loaded over the entire area corresponding to the length of the fulcrum portion and the load per unit area is reduced. . This improves the durability of the film.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. Portions having the same structure as those described with reference to FIGS. A ring 28 made of synthetic resin is fixedly provided on the inner peripheral surface of the yoke 18. The end surface 28a of this ring 28
A plurality of fulcrum portions 28b for supporting the armature 8 so as to be able to rise and fall are formed on the same plane as the end surface 18b of the yoke 18. These fulcrums 28b are formed on a straight line orthogonal to the straight line 8a passing through the center of the armature 8, and the fulcrums 28b and the yoke 18 are provided on both sides of the armature 8.
The inner peripheral edge 1 of the yoke 18 so as to intersect the inner peripheral edge 18c of the
It is close to 8c. A curved surface 28c is formed on the top of each fulcrum portion 28b. These fulcrums 28b
Are continuous so that a polygonal ridge is formed, and the end face 28
An inclined surface 28d is formed in a portion on the inner peripheral side of the fulcrum portion 28b of a so as not to interfere with the undulating motion of the armature 8. The ring 28 is made of a synthetic resin having high mechanical strength such as polyphenylene sulfide (PPS).

In such a structure, by selectively exciting the coil 16, the armature 8 is moved to the core 1.
7 is sucked by the suction surface 17a and rotates about the fulcrum portion 28b. When the coil 16 is de-energized, the armature 8 is moved by the urging force of the armature spring 6 into the core 1.
It separates from 7, and rotates centering around the fulcrum part 28b.

At this time, the film 12 is the armature 8
The fulcrum portion 28b is pressed by the fulcrum portion 28b, and the fulcrum portion 28b is a straight line, and the curved surface 28c is formed on the top of the fulcrum portion 28b. Therefore, the film 12 is uniformly loaded over the entire area corresponding to the length of the fulcrum portion 28b. And the load per unit area is reduced. Thereby, the durability of the film 12 is improved. Therefore, the air gap between the armature 8 and the inner peripheral edge 18c of the yoke 18 is maintained for a long time, and the armature 8 can be returned at high speed.

Further, the ring 28 has a complicated shape because the fulcrum portion 28b is continuously formed in a polygonal shape, but it can be molded with a synthetic resin such as polyphenylene sulfide within an intersection of about 3 μm. Further, by adopting the method of outserting the ring 28 to the yoke 18, it is easy to maintain the relative positional relationship with respect to the yoke 18 with high accuracy.

An annular yoke is arranged on the outer side of a plurality of annularly arranged cores, a ring is provided on the outer periphery of the yoke, and a fulcrum portion orthogonal to the longitudinal direction of the ring armature is provided on the outer peripheral edge of the yoke. Similar effects can be obtained even if they are formed close to each other.

[0016]

As described above, according to the present invention, the synthetic resin ring is fixedly provided along the circumferential direction of the yoke, and the armature is on the same plane as the end surface of the yoke on the straight line orthogonal to the longitudinal direction thereof. Since a plurality of fulcrum portions that are supported up and down in close proximity to the periphery of the yoke are formed on the ring and a curved surface is formed on the top of the fulcrum portion, the film is evenly loaded over the entire area corresponding to the length of the fulcrum portion. With it can reduce the load per unit area, thereby improving the durability of the film, maintaining the air gap between the armature and the peripheral edge of the yoke for a long time, it is possible to return the armature at high speed, Further, there is an effect that a ring made of synthetic resin can be easily molded together with the fulcrum portion with high dimensional accuracy.

[Brief description of drawings]

FIG. 1 is a plan view showing a support structure for an armature according to an embodiment of the present invention.

FIG. 2 is a vertical sectional side view showing a support structure for an armature.

FIG. 3 is a perspective view showing a structure of a fulcrum portion.

FIG. 4 is a vertical sectional side view showing an example of a conventional dot printer head.

FIG. 5 is a vertical sectional side view showing a support structure for an armature.

FIG. 6 is an exploded perspective view showing a worn state of the film.

[Explanation of symbols]

 3 Needle guide 8 Armature 9 Needle 12 Film 16 Coil 17 Core 17a Suction surface 18 Yoke 18b End face 18c Peripheral edge (inner peripheral edge) 24 Platen 28 Ring 28a End face 28b Support point

Claims (1)

[Claims] 1. A plurality of cores magnetically coupled to an annular yoke and arranged along the circumferential direction of the yoke to hold coils, respectively, suction surfaces of these cores and an end surface of the yoke. A plurality of armatures that are arranged in a radial pattern and are opposed to each other via a film for preventing residual magnetism, and a plurality of needles that are slidably held by a needle guide and that are connected to the tip of the armature. In a dot printer head that energizes the coil and drives the armature to cause the tip of the needle to collide with a platen, a synthetic resin ring is fixedly provided along the circumferential direction of the yoke, and the armature is provided in the longitudinal direction thereof. A plurality of fulcrum portions that are supported up and down on a straight line orthogonal to the ridge are formed in the ring close to the peripheral edge of the yoke, and A dot printer head characterized in that a curved surface is formed on a portion thereof.