JPS61217260A - Wire dot head - Google Patents

Abstract

PURPOSE:To offer a wire dot head with muffled noise during operation by evacuating a hermetically sealed holder to hold a drive in a wire dot head which prints by projecting a wire through a drive. CONSTITUTION:An intermediate guide 2' and a back holder 21 are fixed with screws 23 having a heat radiation plate 4 sandwiched between the former two. Under this constitution, the noise source such as solenoid and armature 14 of a wire drive is covered by the intermediate guide and the back holder. The contact surface between the intermediate guide 2' and the heat radiation plate 4 and that between the heat radiation plate 4 and the back holder 21 are hermetically sealed with 0 rings 30. Air is extracted from the sealed interior through an air hole 35 so that it is evacuated. Then the air hole 35 is sealed and a clearance 39 is provided as a vacuum layer. The air one of the noise transmission bodies causing the percussion sound of a stopper 15 by the armature 14, is eliminated, and the transmission of noise to the exterior is significantly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a wire dot, and more particularly to a wire dot head having multiple wires.

(Prior art) Generally, in order to print characters, etc. using dots using a wire dot printer, as shown in Fig. 1, mXn dot matrix configurations and 17 dots are lined up horizontally at a pitch of P1 and vertically at a pitch of P2. The desired printing can be performed by moving the n wires and driving the wires for each shift while performing m synts σ.

The conventional structure of a wire dot head for performing such dot printing is shown in FIGS. 2 to 5.

The reference numeral 1 in FIGS. 2 to 5 is a tip guide, which can be fixed to an intermediate guide 2, which is a front holder. 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 M board 3 and the yoke 5 formed into an elliptical cylinder shape, and transfers the heat of the yoke 5 to the back holder 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 B to form a solenoid.

Two terminals 8a are protruded from the bobbin 8, and the winding start and winding end portions of the coil 7 are fixed to these terminals by soldering. and terminal B.

The solder passes through the yaw 5 and the heat radiation plate 4 and is fixed to the flexible printed circuit board 3 side.

On the other hand, the reference numeral 9 denotes a rear guide, which is formed into a cylindrical shape as a whole, and is fitted into the intermediate kite 2 with the yaw 5, heat dissipation plate 4, and flexible printed circuit board 3 energized 7. It will be placed in

The rear end of this rear guide 9 ζ is V′, L″6I return spring 1
One end of 0 is fixed. On the other hand, the open end of the rear end of the yaw 50 is not closed by the auxiliary yaw 11. A circular opening 11 is formed in the center of the auxiliary yoke 11, and the rear end of the rear guide 9 corresponds to the circular opening 11.

±, the boss 8b protruding from the rear end of the bobbin 8 is fitted into a through hole formed in the auxiliary yoke 11 and protrudes rearward 1
Using this boss) 8b, the rear end of the Manayu 140 is fitted. ing.

1. A spacer 12 is placed between the auxiliary yoke 11 and the armature 14. This spacer 12 is protected against wear due to contact between the auxiliary yoke 11 and the armature 14.
Prevents the movement of the armature 14 from becoming unstable due to residual magnetism of the auxiliary yoke 11, which is a problem when forming a closed magnetic path.
, is set up to do so.

As shown in FIG. 5, a plurality of armatures 14 are arranged radially, and a base end of a wire 220 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 free end of the armature 14 is always positioned behind the rear guide 9. A force is applied in the direction away from the edge.

On the other hand, a stopper 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 14. This stopper 15 is fitted into an armature holder 16, and the tip of each arm of the radially formed armature holder 16 is in a state where the base end side of the armature 14 is pressed against the auxiliary yoke 11. There is. This armature holder 16
The pressing force of each arm against the armature 14 is applied by a similarly radial leaf spring 17 arranged at the rear of the armature holder 16. By the way, a damper 18 is arranged behind the leaf spring 17. This damper 18 is made of a material with high specific gravity such as lead, and the washer 19,
It is arranged in contact with a back holder 21 via a spring washer 20.

Note that the back holder 21 has a large influence 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. 3, a large number of fins are formed on the outside.

This back holder 21 is placed at the same position as the intermediate guide 2.
3 is thus fixed, and the armature and yoke parts are removed as a whole.

By the way, the damper 18 is made up of a leaf spring 17 and a spring washer 20.
The structure is such that the anti-vibration effect is enhanced by providing the structure so that it can be displaced.

Also, the washer 19 is attached to the damper 18 with the spring washer 2[+
Shake to prevent it from digging in.

In addition, the wire 22 is attached to each guide 1.2.9 to prevent buckling.
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 this structure, when the coil 7 is energized according to the printing command, a closed magnetic path is formed by the yoke 5, the auxiliary yoke 11, the plunger 13, and the core 6, and the plunger 16 is The wire 22 is attracted toward the core 6 and is caused to protrude a predetermined distance from the tip guide 1 against the elastic force of the armature t4r;i: return bar;f, 10.

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

When the wire 22 finishes printing, the printing command stops the supply of electricity to the coil 7, so the attraction force of the core 6 disappears, and the plunger 15 and armature 14 move in the opposite direction to the printing direction due to the repulsive force of the return spring 100. Move.

Then, the armature 14 hits the stopper 15 and stops +L
L, the wire is in the stored state.

In order to dot print characters with a P9r standard, this operation is repeated based on the print command, but because of this structure, when printing with a wire dot head, armature 1
4, there is a drawback that a large amount of noise is generated mainly from the impact sound of the stopper 15.

(Objective) An object of the present invention is to eliminate the above-mentioned drawbacks and provide a wire dot head that produces less noise during operation.

(Example) FIG. 6 shows a wire dot head according to an embodiment of the present invention.

2' is an intermediate guide which is also a front holder, and 21' is a back holder, both of which have grooves 2'c and 21'c for inserting an O-ring 61 for sealing. Also, 3
2 is a permanent magnet, 53 is a magnetic fluid, 34 is a yoke, and 65 is an air hole; other than this, the structure is the same as in FIG. The intermediate guide 2' and the back holder 21' are fixed by screws 26 with the heat dissipation plate 4 interposed therebetween, and cover sound-generating parts such as the solenoid and the armature 14 which are wire drive parts. The contact surfaces between the intermediate guide 2' and the heat dissipation plate 4 and the contact surfaces between the heat dissipation plate 4 and the back holder 21' are sealed by an O ring 3o, and a magnetic fluid 33 is provided between the wire 22 and the guide portion C of the intermediate guide 2'. It is sealed by. This magnetic fluid 55 generates a magnetic field that is magnetized to a strength that is strong enough not to destroy the main fluid layer even if the pressure difference is atmospheric pressure, and even if the wire 22 moves in the printing direction for printing. It holds a permanent magnet 32 that allows it to move.

At this time, the air inside is removed from the air hole 35 to create a vacuum and the air hole 35 is sealed. Due to this sealing, the gap 59 becomes a vacuum layer. In this way, since air, which is one of the transmission media for the noise caused by the impact sound of the stopper 15 by the armature 14, is eliminated, the transmission of noise to the outside is greatly reduced.

It is also possible to replace the O-ring 31 in the above embodiment with a magnetic fluid as shown in FIG. At this time, the magnetic field of the permanent magnet 67 that holds the magnetic transfer body layer 56 will not affect the wire drive magnetic circuit as long as the magnetic path is closed in the fluid layer portion. ! +8 is a yoke.

Note that the present invention is not limited to the above embodiments. For example, the embodiment is a magnetic attraction type head that makes the wire stick out by attracting the armature with a solenoid. It may be a release type head.

Furthermore, even if a solenoid is used, the present invention can also be applied to a head in which the wire is made to protrude by a driving section using an electrostrictive element.

(Efficacy) Above explanation 1. As described above, the present invention makes it possible to significantly reduce noise by creating a vacuum inside the holder of the wire dot head.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing a printing method using a wire dot head, and Figures 2 to 5 are explanatory diagrams of conventional structures.
The figure is a cross-sectional plan view, Figure 3 is an exploded perspective view, Figure 4 is a view from the A-A line in Figure 2, Figure 5 is a view from the B-n Hi arrow in Figure 2, and Figures 6 and below. 6 is a cross-sectional plan view, and FIG. 7 is a cross-sectional plan view of a modified part of another embodiment in which a part of the present invention is modified. 2'...Intermediate guide 21'...Back holder 51...0 ring 32...Permanent magnet 53...Magnetic fluid 54...Yoke filter 5...Air hook hole 56... Magnetic fluid layer 57...Permanent magnet 68...Yoke

Claims (2)

[Claims] (1) A wire dot head that performs printing by protruding a wire using a drive unit, characterized in that a holder that accommodates the drive unit has a sealed structure and the inside of the holder is evacuated. (2) The wire dot head according to claim 1, characterized in that a magnetic fluid is used as the sealing means of the sealed structure.