JPS6250072A - Wire dot head - Google Patents

Abstract

PURPOSE:To maintain always constant stroke of wires by providing steps to prohibit the flow of a brazing filler metal to the part for brazing a wire at the top end of each armature of a wire dot head. CONSTITUTION:The dot head makes dot recording by attracting and driving plural pieces of the armatures 14 brazed with the base ends of the wires 22 at one end by electromagnets. The upper and lower step parts 14a, 14b and through-hole 14c are formed to the top end of each armature 14 in the stage of uniting and connecting the wires 22 and the armatures 14 to constitute such armature 14. The brazing filler metal 24 accumulates in the step parts 14a, 14b and the flow thereof toward the side face direction of the armatures 14 is prohibited when the root ends of the wires 22 are fitted into the through-holes 14 and the wires 22 are brazed to the armatures 14. The always the constant wire stroke in the dot recording stage is thus maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire dot head, and more particularly to a wire dot head equipped with a large number of wires.

[Prior Art] In order to print characters, etc. using dots, as shown in Fig. 4, an mXn dot matrix configuration is used, in which n dots are arranged horizontally at a pitch of Pl and vertically at a pitch of Pl. By moving the wire and shifting it m times, and driving the wire for each shift, the desired printing can be performed.

The conventional structure of a wire dot head for performing such dot printing is shown in FIGS. 5 to 8.

In FIGS. 5 to 8, the reference numeral 1 indicates a tip guide, which is fixed to the intermediate guide 2. As shown in FIGS.

The intermediate guide 2 is formed with a notch 2a for a screw to be attached to a carriage (not shown).

A flexible printed circuit board 3 that is integrated with a heat dissipation plate 4 is arranged behind the intermediate guide 2.

The heat dissipation plate 4 also serves as a spacer between the flexible printed circuit board 3 and the yoke 5 formed in the shape of an elliptical cylinder, and transmits the heat of the yoke 5 to a back holder, which will be described later.
A material with excellent thermal conductivity such as aluminum with a thickness of about 2 mm is selected.

A plurality of cores 6 are fitted and fixed to the yoke 5, and a bobbin 8 around which a coil 7 is wound is attached to the core 6.

Two terminals 8a are protruded from the pobbin 8, and the winding start and winding end portions of the coil 7 are fixed to these by soldering. The terminal 8a is connected to the yoke 5. It penetrates through the heat dissipation plate 4 and is fixed to the flexible printed circuit board 3 side by soldering.

On the other hand, the reference numeral 9 denotes a rear guide, which is formed into a cylindrical shape as a whole, and is connected to the yoke 5° heat dissipation plate 4.
．． The intermediate guide 2 passes through the flexible printed circuit board 3.
It is placed in a state where it is fitted inside.

One end of a return spring lO is fixed to the rear end of this rear guide 9. On the other hand, the open end of the rear end of the yoke 5 is closed by an auxiliary yoke 11. A circular opening is formed in the center of the auxiliary yoke 11, and the rear end of the rear guide 9 corresponds to this opening.

Further, a boss 8b protruding from the rear end side of the pobbin 8 is fitted into a through hole formed in the auxiliary yoke 11 and protrudes rearward. are fitted.

The number of armatures 14 is the same as the number of wires 22, and a plunger 13 is provided in the middle thereof.

Further, a spacer 12 is arranged between the auxiliary yoke 11 and the armature 14.

This spacer 12 is connected to the auxiliary yoke 11 and the armature 14.
This is provided to prevent the movement of the armature 14 from becoming unstable due to wear caused by contact with the auxiliary yoke 11 or residual magnetism of the auxiliary yoke 11, which may cause problems when forming a closed magnetic path.

As shown in FIG. 6, a plurality of armatures 14 are arranged radially, and the proximal end of the wire 22 is fixed to the distal end thereof. The return spring 10 is loaded between the free end of the armature 14 and the rear end of the rear guide 9, and the return spring 10 always keeps the free end of the armature 14 behind the rear guide 9. A force is applied in the direction away from the edge.

On the other hand, a stopper/pa 15 is arranged behind the armature 14 and faces a position where it can come into contact with the free end side of the armature 4. This stopper 15 is fitted into a stopper holder 16, and the tip of each arm of the radially formed armature presser spring 17 is in a state in which the base end side of the armature 14 is pressed against the auxiliary yoke 11. ing.

By the way, a damper 18 is arranged behind the armature presser spring 17. This damper 18 is made of a material with high specific gravity such as lead, and the washer 19. /< 7 is placed in contact with the bag holder 21 via the washer 20 .

Note that the back holder 21 has a large effect on the heat dissipation of the head, so the surface area of the back holder 21 should be made as large as possible.
As shown in FIG. 4, a large number of fins are formed on the outside.

This back holder 21 has screws 23 attached to the intermediate guide 2.
It is fixed in place and covers the armature and yoke as a whole.

Further, the washer 19 prevents the spring washer 20 from biting into the damper 18.

In addition, since the wire 22 is buckled W, each guide 1.2.9
The plurality of wires 22 are guided along these guides so as to gradually form a vertical line, and are completely arranged in a vertical line within the tip guide 1.

In order to print based on such a structure, when the coil 7 is energized according to the printing command, the yoke 5. Auxiliary yoke 11. Plunger 13. Since a closed magnetic path is formed by the core 6, the plunger 13 is attracted toward the core 6, and the armature 14 causes the wire 22 to protrude a predetermined distance from the tip guide 1 against the elastic force of the return spring IO.

The wire 22 prints dots on the paper via an ink ribbon (not shown).

[Problems to be solved by the invention] However, when the above structure is adopted, the wire 22
Since the wire and the armature 14 are integrally connected, the brazed portion becomes an obstacle to keeping the stroke of the wire constant.

That is, the stroke of the wire 22 is controlled by the armature 14 rotating between the stopper 15 and the auxiliary yoke 11 using the post 8b fixed to the auxiliary yoke 11 as a fulcrum.

Therefore, the brazing agent flows down the side of the armature and accumulates where it hits the stopper and auxiliary yoke, and the apparent thickness of the armature becomes thicker.The stroke of the wire becomes shorter than that of a normal stroke. There were drawbacks such as variations in the density of dots forming characters and the like, and severe damage to the ink ribbon.

[Means for Solving the Problems] In the present invention, in order to solve the above-mentioned problems, a stepped portion is provided in the part of the armature where the wire is brazed to prevent the brazing agent from flowing toward the armature. structure was adopted.

[Function] When the above-mentioned structure is adopted, the brazing agent accumulates in the stepped portion, and the waxing agent does not flow in the side direction of the armature, thereby increasing the apparent wall thickness of the portion of the armature that contacts the stopper and auxiliary yoke. This allows the wire stroke to be kept constant at all times.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

[First Embodiment] FIGS. 1A and 1B illustrate a first embodiment of the present invention. In this embodiment, there are difference portions 14a above and below the tip of the armature 14. .

14b, and a through hole 14c into which the base end of the wire 22 fits is formed.

If such a structure is adopted, as shown in FIG. 1(B), when the base end of the wire 22 is brazed with the brazing agent 24, the brazing agent 24 will form a gap portion 14a.

It accumulates in the armature 14b and does not flow toward the side of the armature 14.

Therefore, problems such as an increase in the apparent thickness of the armature at the portions that contact the stopper and the auxiliary yoke do not occur, and the stroke of the wire can always be kept constant.

[Second Embodiment] FIGS. 2(A) and 2(B) illustrate a second embodiment of the present invention. In this embodiment, only one side surface of the tip of the armature 14 is A stepped portion 14d is formed, and a through hole 14c into which the base end of the wire 22 fits is formed.

Such a structure is easy to process even if the bare mature plate is thinner than the first embodiment, and even if it is adopted, the brazing agent 24
Most of the brazing agent accumulates on the stepped portion 14d, and the stroke of the wire can be kept constant without accumulating in the area where the armature contacts the stopper/auxiliary yoke.

[Third Embodiment] FIGS. 3A and 3B illustrate a third embodiment of the present invention. In this embodiment, a groove 14e is formed on one side of the tip of the armature 14. is formed as a stepped portion.

A through hole 14c into which the wire 22 fits is formed outside the groove 14e.

If such a structure is adopted, the flow of the brazing agent 24 is blocked in the groove 14e, and the stroke of the wire can be kept constant without flowing to the part where the armature contacts the stopper or the auxiliary yoke.

[Effects] As is clear from the above description, according to the present invention, a stepped portion is provided in the vicinity of the portion where the wire is brazed and fixed at the tip of the armature to prevent the brazing agent from flowing to the side surface of the armature. Because the wire has a similar structure, the brazing agent does not adhere to the part of the armature that comes in contact with the stopper or auxiliary yoke, so the wire stroke can always be kept constant.

[Brief explanation of drawings]

FIGS. 1(A) and (B) are perspective teeth and partially cutaway side views explaining the first embodiment of the present invention, and FIGS. 2(A) and (B) are the second embodiment of the present invention. FIG. 3A is a perspective view and a partially cutaway side view for explaining. (B) is a perspective view explaining the third embodiment of the present invention and 1
Partially broken side view, Figure 4 is an explanatory diagram of the dot matrix,
Fig. 5 is a longitudinal cross-sectional side view of the wire dot head, Fig. 6 is an exploded perspective view of the wire dot head, and Fig. 7 is a cross-sectional view of the wire dot head.
A view taken along the line A, and FIG. 8 is a view taken along the line B--B in FIG. 1. 5... Yoke 6... Core 7... Coil pobbin 14... Armature 15... Stopper -6... Stopper holder 22... Wire

Claims (1)

[Claims] In a wire dot head that records dots by attracting and driving multiple armatures, each of which has a wire base end brazed to one end, using an electromagnet, there is a stepped part that prevents the flow of brazing agent into the brazed part of the wire at the tip of the armature. A wire dot head characterized by the provision of.