JPH05147233A - Print head for wire dot printer - Google Patents

Abstract

PURPOSE:To prevent a stopper member from floating in the armature direction and to prevent responsibility from decreasing and accordingly quality of printing from changing for the worse by energizing always the stopper member in the anti-armature direction by an elastic means. CONSTITUTION:A stopper member 37 consisting of a ring 39, a metal plate 41, a rubber 43 and a spacer 45 is energizied always in the anti-armature 19 direction by means of a sheet spring member 51. Even if all the pins are driven, namely, all the electromagnetic parts 17 are excited and all the armatures 19 are moved against the energizing force of a coil spring 25, the stopper member 37 does not float up to the armature 19 side. It is thereby eliminated that returning action of the armature 19 is spoiled and timing of returning is delayed and responsibility thereafter is decreased and quality of printing is changed for the worse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head of a wire dot printer, and more particularly to a stopper member which exerts an interference function when the armature is returned so that it is always urged in an anti-armature direction by elastic means. By configuring, the stopper member floats in the armature direction,
The present invention relates to a device configured to prevent a decrease in responsiveness.

[0002]

2. Description of the Related Art The print head of a conventional wire dot printer has a structure as shown in FIG. First, there is a nose 101, and wire guides 103 and 105 are installed in the nose 101, and a plurality of wires (only two are shown in the figure) are guided by the wire guides 103 and 105. 107 is arranged to be movable in the left-right direction in the drawing.

A hollow cylindrical portion 109 of the nose 101 is extended to the right side in the drawing, and a core unit 111 is installed on the outer peripheral side of the hollow cylindrical portion 109. The core unit 111 includes a tubular member 113, and a plurality of electromagnet portions 115 are installed in an annular space portion between the tubular member 113 and the hollow cylindrical portion 109. The electromagnet part 115 includes an iron core 117 and the iron core 11
7 and a coil 119 arranged on the outer peripheral side.

The base ends of the plurality of wires 107 are connected to the armature 121, respectively. It is the plurality of electromagnet sections 115 that drive each of these armatures 121. A cylindrical member 123 is mounted on the inner peripheral portion of the hollow cylindrical portion 109, and a plurality of coil springs 125 corresponding to the plurality of armatures 121 are mounted on the cylindrical member 123.
When the electromagnet portion 115 is not excited, the armature 121 is urged by the coil spring 125 to the initial position (standby position on the right side in the drawing). On the other hand, when the electromagnet portion 115 is excited, the armature 121 is attracted to the left side in the figure against the biasing force of the coil spring 125. As a result, the wire 107 is projected.

The back side of the core unit 111 (right side in the figure)
A holding member unit 127 is installed in the. With this holding member unit 127, the armature 1
The position of 21 is determined and held. A stopper member 129 is installed on the inner peripheral side of the holding member unit 127, and a metal plate 131 is installed on the back side of the stopper member 129 and is fixed by a screw member 133. The stopper member 129 is formed by laminating a plurality of plate members and a plurality of film-shaped members, and the gap between the iron core 117 and the armature 121 is set by appropriately setting the thickness thereof. Thereby, a desired printing power is obtained. Further, the stopper member 129 also exerts a function of absorbing a shock when the armature 121 returns to the initial position.

[0006]

The above-mentioned conventional structure has the following problems. The stopper member 129 is not particularly biased toward the anti-armature 121,
The coil spring 125 presses the armature 121 to the side opposite to the armature 121, that is, the side of the metal plate 131 only by the returning force that returns the armature 121 to the initial position. Therefore, for example, when all the pins are driven, that is, all the electromagnet parts 115 are excited and all the armatures 121 are moved to the coil springs 12.
When the stopper member 129 is moved to the left side in the figure against the urging force of 5, the force for pressing the stopper member 129 toward the metal plate 131 side disappears, and the stopper member 129 is moved to the armature 1 side.
It will surface to the 21st side.

The stopper member 129 is the armature 121.
When the armature 121 returns to the initial position in the state of being levitated to the side, the floating stopper member 129 impairs the return operation of the armature 121 at the regular timing. That is, the returning armature 121 returns to the normal standby position after colliding with the floating stopper member 129. Therefore, there is a problem in that the timing of returning to the standby position is delayed, and the timing of the next printing operation is deviated, and the responsiveness of continuous printing is reduced, which in turn deteriorates the printing quality. It was

The above problem will be described with reference to FIGS. 7 and 8. 7 and 8 are diagrams showing the relationship between the two, with the horizontal axis representing time and the vertical axis representing the displacement of the armature 121. 7 shows a normal case, and FIG. 8 shows a case where the responsiveness is lowered due to the floating of the stopper member 129. First, in FIG. 7, an arbitrary electromagnet unit 1
When 15 is excited at time (t ₀ ), the corresponding armature 121 begins to operate. And time (t ₁ )
Then, the tip of the needle (not shown) collides with the platen (not shown) via the ink ribbon (not shown). Printing is thereby performed. After that, the rebounded needle returns to the standby position at time (t ₂ ) and the stopper member 129
The next printing operation is performed while bounding by colliding with.

On the other hand, in the case shown in FIG. 8, the first printing operation from time (t ₀ ') to (t ₂ ') is normally performed, but the second printing operation is performed. In the returning operation, that is, in the process from time (t ₃ ') to time (t ₄ '),
The normal return operation is impaired, and it takes a longer time than in the normal case to return to the standby position at time (t ₄ '). This is because the armature 121 collides with the floating stopper member 129 at the position indicated by a in the figure. Such a phenomenon is also seen in the subsequent printing operation. Therefore, the period between dots becomes unstable and the dot pitch is disturbed.

Further, there is the following problem as another problem. For example, a large number of all pins (for example, 7 to 8)
Assume that the pins are driven simultaneously. In that case,
A plurality of armatures 121 corresponding to those pins are simultaneously driven and simultaneously returned. At that time, the stopper member 129 has a plurality of armatures 12.
There is a phenomenon in which the armature 121, which has not been driven, is flipped up due to the shock caused by the collision of No. 1. Therefore, there is a problem that the needle pops out unnecessarily and is caught by the ink ribbon, which causes various problems.

The present invention has been made on the basis of such a point. An object of the present invention is to prevent the stopper member from floating in the armature direction and to reduce the responsiveness due to the floating of the stopper member. An object of the present invention is to provide a print head of a wire dot printer that can prevent deterioration of print quality.

[0012]

In order to achieve the above object, a print head of a wire dot printer according to the present invention comprises:
A nose having a base end movably holding a wire fixed to an armature, a core unit arranged on the back side of the nose and driving the armature, and the armature and the core unit arranged on the back side of the core unit. A holding member unit for holding the position of the armature, a stopper member provided on the back side of the armature and exerting an interference function when the armature returns, and an elastic means for urging the stopper member to the side opposite to the armature. It is characterized by having done. At that time, it is conceivable that the elastic means urges the stopper member uniformly in the circumferential direction toward the side opposite to the armature at a plurality of locations corresponding to the number of armatures.

[0013]

In the case of the present invention, the elastic means is provided so that the elastic means always urges the stopper member in the direction opposite to the armature. Thereby, even if all the armatures are driven when all the pins are driven, the stopper member is prevented from floating in the armature direction. Further, when the elastic means is such that the stopper member is uniformly biased in the circumferential direction to the side opposite to the armature at a plurality of positions corresponding to the number of armatures, the stopper member is kept in a uniform state without being tilted. Can be biased in the anti-armature direction.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment of the present invention will be described below with reference to FIGS.
An example will be described. First, there is a nose 1, and the wire guides 3, 5, and 7 are incorporated in the nose 1. A plurality of (only two in the figure) wires 9 are arranged so as to be movable in the left-right direction in the figure while being guided by these wire guides 3 to 7. A core unit 11 is attached to the back side (right side in the figure) of the nose 1.

The core unit 11 is provided with an inner cylindrical member 13 having a substantially cylindrical shape at the center thereof, and an outer cylindrical member 15 is installed on the outer peripheral side of the inner cylindrical member 13.
A plurality of electromagnet parts 17 are arranged in an annular space portion between the inner cylinder member 13 and the outer cylinder member 15. That is, the plurality of wires 9 are fixed to the armatures 19 by brazing, and the armatures 19 are respectively driven by the electromagnet portions 17. In addition, also in the inner peripheral portion of the inner cylinder member 13,
A wire guide 20 is attached.

The electromagnet portion 17 is composed of an iron core 21 and a coil 23 provided on the outer peripheral side of the iron core 21. A coil spring 25 corresponding to a plurality of armatures 19 is provided in the inner tubular member 13, and the coil springs 25 return the armature 19 to an initial position (a standby position to the right in the figure). It is designed to let you. When the electromagnet portion 17 is de-excited, the armature 19 moves to the coil spring 25.
Biased to the initial position by the wire 9
Is also retracted to the standby position. On the other hand, when the electromagnet portion 17 is excited, the armature 19 is attracted to the left side in the figure against the biasing force of the coil spring 25. As a result, the wire 9 is projected.

A holding member unit 27 is incorporated on the back side (right side in the figure) of the core unit 11.
The holding member unit 27 includes a holding member 29, and inside the holding member 29, the armature 19 already described is accommodated, and at the same time, the armature 19 is held.
Fixing members 31, 33, and 35 for preventing the floating of the are housed. A stopper member 37 is arranged inside the fixing members 31 to 35. The thickness of the stopper member 37 is adjusted so as to set the gap between the armature 19 and the iron core 21, and the stopper member 37 has a structure in which a resin ring 39, a metal plate 41, a rubber 43, and a spacer 45 are laminated. ing. Further, the stopper member 37 is
It also exerts a damper function to mitigate the impact when the armature 19 returns to the initial position.

The resin ring 39 has a shape as shown in FIG. 2, and comprises a ring body 47 and a plurality of projecting pieces 49 projecting radially outward from the ring body 47. There is. Armature 19 of the above ring 39
On the side, a ring-shaped leaf spring member 51 as elastic means is arranged. The leaf spring member 51 has a shape as shown in FIG. 3, and is composed of a leaf spring member main body 53 and a plurality of projecting pieces 55 projecting radially inward of the leaf spring member main body 53. Has been done.

The ring 39 and the leaf spring member 51 are shown in FIG.
It will be stacked and arranged in the state as shown in FIG. That is, the protruding pieces 55 of the leaf spring member 51 overlap the protruding pieces 49 of the ring 39. In this way, the leaf spring member 51 is arranged on the armature 19 side of the ring 39, and by stacking and arranging them in the state shown in FIG. 4, the ring 39 is constantly urged in the direction opposite to the armature 19 to form a ring. This prevents the stopper member 37 including 39 from floating toward the armature 19 side.

According to this embodiment, the following actions and effects can be obtained. First, the ring 39 and the metal plate 4
1. A stopper member 37 including a rubber 43 and a spacer 45
Is always urged in the direction opposite to the armature 19 by the leaf spring member 51. Therefore, if all the pins are driven, that is, all the electromagnet parts 17 are excited and all the armatures 19 are coil springs 25.
Even if the stopper member 37 moves to the left side in the figure against the urging force of the stopper member 37, the stopper member 37 does not float to the armature 19 side. Therefore, it is possible to prevent the return operation of the armature 19 from being impaired and the return timing to be delayed, which may deteriorate the subsequent responsiveness and deteriorate the print quality.

The projecting piece 49 of the ring 39 of the stopper member 37 is projectingly provided at a position corresponding to the plurality of armatures 19, and the projecting piece 5 of the leaf spring member 51.
5 is also projected in the same arrangement. Therefore, the stopper member 37 can be urged by the plate spring member 51 in a substantially uniform state in the circumferential direction and pressed against the armature 19 side. Therefore, the stopper member 37 does not locally float to the armature 19 side, and it is possible to reliably prevent the portion where the plurality of armatures 19 are arranged from floating.

Further, even when a large number of pins among all the pins are simultaneously driven and returned, the stopper member 37 is always urged in the direction opposite to the armature 19 by the leaf spring member 51, so that the stopper member 37 is returned. Even if a large number of armatures 19 collide, they do not dance, and other armatures 19 do not bounce up and the needles do not pop out unnecessarily. Therefore, it is possible to eliminate various problems caused by unnecessary protrusion of the needle.

Next, a second embodiment of the present invention will be described with reference to FIG. In the case of this embodiment, a plurality of coil springs (elastic means) 61 corresponding to the number of armatures 19 are provided in the inner tubular member 13, and the stopper member 37 is used as a counter armature by the plurality of coil springs 61. It is configured to always urge in 19 directions. The plurality of coil springs 61 are coil springs 25 for returning the armature 19 to the standby position.
It is placed in a position that does not interfere with. Therefore, also in the case of this embodiment, it is possible to prevent the stopper member 37 from floating toward the armature 19 by the plurality of coil springs 61, so that the same effect as in the case of the first embodiment can be obtained. You can

The present invention is not limited to the above embodiments. For example, as the elastic means, it is possible to use elastic rubber or the like in addition to the leaf spring member 51 and the coil spring 61. Also, when the leaf spring member 51 is used, the shape and the like are not limited to those shown in the drawings. Further, the number of acting portions for urging the stopper member 37 in the direction opposite to the armature 19 is not limited to that in each of the above embodiments. Further, the location of the elastic means is not limited to this.

[0025]

As described in detail above, according to the print head of the wire dot printer of the present invention, the stopper member is always biased in the anti-armature direction by the elastic means, so that the stopper member is moved in the armature direction. It is possible to prevent the floating of the ink, and thus to prevent the deterioration of the responsiveness and the deterioration of the printing quality.
Also, if many of the pins are driven back at the same time and return, the returned armatures will not dance even if they collide, and the other armatures will be flipped up, and the needle will not move. There is no need to jump out. Therefore, it is possible to eliminate various problems caused by unnecessary protrusion of the needle. Further, in the case where the stopper member is uniformly biased through a plurality of positions in the circumferential direction, the stopper member can be pressed in the anti-armature direction without tilting.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a print head of a wire dot printer, showing a first embodiment of the present invention.

FIG. 2 is a plan view of the ring of the stopper member in the drawing showing the first embodiment of the present invention.

FIG. 3 is a plan view of a leaf spring member showing the first embodiment of the present invention.

FIG. 4 is a plan view showing the positional relationship between the ring of the stopper member and the leaf spring member in the first embodiment of the present invention.

FIG. 5 is a view showing a second embodiment of the present invention, in which a print head of a wire dot printer is partially cut away when viewed from the back side of a stopper member.

FIG. 6 is a cross-sectional view of a print head of a wire dot printer showing a conventional example.

FIG. 7 is a diagram used to explain a conventional example and is a diagram showing a relationship between displacement amount of an armature and time.

FIG. 8 is a diagram used for explaining a conventional example and is a diagram showing a relationship between a displacement amount of an armature and time.

[Explanation of symbols]

 1 Nose 9 Wire 11 Core Unit 19 Armature 27 Holding Member Unit 37 Stopper Member 51 Leaf Spring Member (Elastic Means)

Claims (2)

[Claims] 1. A nose having a base end movably holding a wire fixed to an armature, a core unit arranged on the back side of the nose and driving the armature, and a nose arranged on the back side of the core unit. A holding member unit that holds the positions of the armature and the core unit, and a stopper member that is provided on the back side of the armature and exhibits an interference function when the armature returns.
A print head for a wire dot printer, comprising: elastic means for urging the stopper member to the side opposite to the armature. 2. The print head for a wire dot printer according to claim 1, wherein the elastic means urges the stopper member uniformly in the circumferential direction toward the side opposite to the armature at a plurality of locations corresponding to the number of armatures. The print head of a wire dot printer characterized by.