JPH06166187A - Impact dot head - Google Patents

Abstract

PURPOSE:To prevent a metal stopper from scattering at its cracking and improve durability. CONSTITUTION:A resin spacer 103 is stuck and connected to a rear face (an opposite face of impact face against an armature) of a metal stopper 102. Thus, the metal stopper 102 do not scatter even when it is cracked due to abrasion, so that the durability until fatal failure due to entrance of the metal stopper 102 into a sucking face will be improved.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art An impact dot head prints by selectively projecting a required number of armatures, each of which has a print wire engaged at its tip, by an electromagnet, and has a structure shown in FIG. 4, for example. . FIG. 4 is a sectional view of the entire impact dot head showing a conventional technique.
The armature 6 is attracted by energizing the drive coil 7, and the printing wire 14 engaged with the tip of the armature 6 strikes the printing paper 23 on the platen 24 via the ink ribbon 22 to form dots on the printing paper 23. The armature 6 includes the print wire 14, the ink ribbon 22, and the print paper 2.
3. The repulsive force due to the collision with the platen 24 and the spring force of the coil spring 15 return the coil to the standby position. The elastic body 28 is provided to absorb the impact force of the armature 6 when it is returned and to quickly return the armature 6 to a predetermined standby position.
Is installed on the anti-platen side of the armature 6. A metal stopper 102 is provided on the elastic body 28 in order to prevent the armature 6 from cutting into the elastic body 28 and breaking the elastic body 28 as disclosed in, for example, Japanese Utility Model Laid-Open No. 2-40441. It is installed.

[0003]

However, since the metal stopper 102 repeatedly collides with the armature 6, if the metal stopper 102 is used for a long period of time, the metal stopper 102 is not used.
Wear progresses, eventually leading to fracture. Even if the metal stopper 102 breaks, it does not immediately result in defective printing,
When the fragments of the metal stopper 102 scatter and enter the suction surface 29, the stroke of the armature 6 fluctuates, causing a reduction in printing energy and a poor response.
It was the cause of printing failure.

[0004]

In order to solve the above problems, the impact dot head of the present invention drives an armature by an electromagnet, performs printing by a printing wire engaged with the tip of the armature, and returns the armature. In an impact dot head in which a metal stopper is attached to the surface of an elastic body that absorbs repulsion at the time, place a resin spacer on the surface opposite to the collision surface of the metal stopper with the armature, and fix the resin spacer and the metal stopper. It is characterized by being joined.

[0005]

[Function] Even if the metal stopper is broken due to wear, the resin spacer on the back surface of the metal stopper (the surface opposite to the collision surface with the armature) prevents the metal stopper from scattering,
Prevents metal stopper fragments from getting into the suction surface, which causes printing defects.

[0006]

EXAMPLES The present invention will be described in detail below based on examples.

FIG. 1A is a front view of an impact dot head showing an embodiment of the present invention, and FIG. 1B is a side view of the same. 2 is a sectional view taken along line AA in FIG. FIG. 3 is an exploded partial perspective view showing a stopper portion which is a characteristic portion of the embodiment of the present invention.

The core block 2 made of a magnetic material has a plurality of cores 2a standing upright, and a drive coil 7 in which a copper wire is wound around a coil bobbin 9 is attached around the cores 2a to form an electromagnet. . Two through holes are provided on the bottom surface of the core block 2 so as to correspond to each core 2a, and the coil terminal 10 of the drive coil 7 is conductively fixed to the board 17 through the through hole and the insulating plate 20 by soldering. ing. A connector 25 is soldered to the lower portion of the board 17, and the drive coil 7 is connected to a driver circuit (not shown) by a cable 26. A dish-shaped yoke 3, a fulcrum spacer 5, a disc-shaped yoke 4, a fulcrum spacer 5, and a fulcrum pressing member 21 are laminated on the upper surface (left side surface in FIG. 2) of the core block 2. The integrally formed armatures 6 are arranged at the circumferentially equally-divided positions at the facing portions of the core 2a.
The tip of the armature 6 and the engaging portion of the print wire 14 are located at evenly divided positions on the circumference, and both are fixed by brazing. The armature 6 is provided with a through hole 6a, the fulcrum shaft 18 is inserted into the through hole 6a, and the armature 6 is rotatably held around the fulcrum shaft 18. The fulcrum shaft 18 is sandwiched between two fulcrum spacers 5, and is fixed by pressure contact with the dish-shaped yoke 3 and a fulcrum pressing member 21. The printing wire 14 includes a tip guide 11 attached to the nose 1, a plurality of intermediate guides 12, and a spring holder 1.
3 is held by a guide portion 13b provided on the guide wire 13 and is guided by the tip portion of the print wire 14 in a zigzag arrangement in two vertical columns. A spring holder 13 provided with a cylindrical hole 13a for holding the coil spring 15 is arranged at the central opening of the core block 2, and the coil spring 15 is provided in each cylindrical hole 13a.
Is inserted, and the coil spring 15 urges the armature 6 so as to always abut against the damper set 101.
As shown in FIG. 3, the damper set 101 includes a metal stopper 102, a resin spacer 103, an elastic body 28, and an adjusting spacer 27, and is installed in the recess 21 a at the center of the fulcrum pressing member 21.

Metal stopper 102 and resin spacer 10
As shown in FIG. 3, the metal stopper 102 is formed of a thin metal plate such as stainless steel, and its back surface (the surface opposite to the surface that collides with the armature) is made of resin. A spacer 103 is provided, and the metal stopper 102 and the resin spacer 103 are fixed to each other with an adhesive. The resin spacer 103 is made of polyimide having excellent wear resistance. In addition, the adjustment spacer 27
Is for adjusting the reciprocating stroke of the armature 6, and is made of a resin sheet such as polyester. In this embodiment, the metal stopper 102 and the resin spacer 103 are joined by an adhesive, but they may be joined by heat fusion.

Next, the operation of the impact dot head thus constructed will be described. When a drive current is applied to the drive coil 7, the core 2a attracts the armature 6. As a result, the armature 6 swings with the fulcrum shaft 18 as a fulcrum, and the print wire 14 fixed to the tip projects in the platen 24 direction. As a result, the print wire 14 collides with the print paper 23 and the platen 24 via the ink ribbon 22 to form dots. When printing is completed, the platen 24, the printing paper 23, the ink ribbon 22, and the printing wire 1
The armature 6 is returned to the standby position by the reaction force of collision with the coil 4 and the spring force of the coil spring 15. At this time, the armature 6 collides with the damper set 101. Therefore,
The metal stopper 102 that directly collides with the armature 6 is gradually worn and eventually broken. However, since the metal stopper 102 is bonded to the resin spacer 103, the metal stopper 1 is also broken until the resin spacer 103 is also broken.
No. 02 does not scatter, and the time until a fatal failure (the state where the metal stopper scatters and enters the suction surface) becomes long. When the metal stopper breaks, the stroke of the armature increases, the print becomes slightly thin, and it is possible to know when to replace the impact dot head before a fatal failure due to scattering of the metal stopper is reached.

Further, the present embodiment has been described by taking an example of a so-called direct attraction type impact dot head in which the print wire is projected by attracting the armature with the electromagnet.
In a so-called spring charge type impact dot head, in which flexure energy is accumulated in the spring by the attraction force of the permanent magnet, the attraction force of the permanent magnet is released by the electromagnetic coil, and the flexure energy of the spring is released to drive the printing wire. Also has exactly the same effect.

[0012]

As described above, according to the present invention, since the metal stopper is adhered to the resin spacer even if the base portion of the metal stopper is broken, fragments of the metal stopper do not immediately scatter. It is possible to lengthen the time until printing failure. If the metal stopper breaks,
The armature stroke is increased, the print is slightly thinned, and the impact dot head replacement time can be known before the fatal failure due to the scattering of the metal stopper is known, and the reliability of the printer as a complete product is also improved. .

In the above-mentioned embodiment, the impact dot head of the so-called direct attraction type in which the print wire is projected by attracting the armature with the electromagnet has been explained, but the bending energy of the spring is applied by the attraction force of the permanent magnet. The same effect can be obtained also in a so-called spring charge type impact dot head in which the print wire is driven by accumulating and releasing the attraction force of the permanent magnet by the electromagnetic coil and releasing the bending energy of the spring.

[Brief description of drawings]

FIG. 1 is a front view and a side view of an impact dot showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an impact dot showing an embodiment of the present invention (A-A cross section in FIG. 1).

FIG. 3 is an exploded perspective view showing a stopper portion which is a characteristic portion of the embodiment of the present invention.

FIG. 4 is a cross-sectional view of an impact dot head showing a conventional technique.

[Explanation of symbols]

 1 Nose 2 Core block 3 Disc-shaped yoke 4 Disc-shaped yoke 5 Support point spacer 6 Armature 7 Drive coil 9 Coil bobbin 10 Coil terminal 11 Tip guide 12 Intermediate guide 13 Spring holder 14 Print wire 15 Coil spring 17 Substrate 18 Support shaft 20 Insulation plate 21 fulcrum holding member 22 ink ribbon 23 printing paper 24 platen 25 connector 26 cable 27 adjusting spacer 28 elastic body 101 damper set 102 metal stopper 103 resin spacer

Claims (1)

[Claims] 1. An impact dot head in which an armature is driven by an electromagnet, printing is performed by a printing wire engaged with the tip of the armature, and a metal stopper is attached to the surface of an elastic body that absorbs repulsion when the armature returns. The impact dot head according to claim 1, wherein a resin spacer is disposed on a surface of the metal stopper opposite to a collision surface with the armature, and the resin spacer and the metal stopper are fixedly joined.