JPH0624013A - Impact dot head - Google Patents

Abstract

PURPOSE:To prevent the lever stroke variation generated by the creeping of an armature stopper by bringing the outer periphery end of a lever holder into contact with a yoke and forming the armature stopper by a metal. CONSTITUTION:An armature stopper 19 is formed by a metal such as brass or aluminum for the purpose of preventing creeping. An armature 2 is so installed as to be pressed by a reset spring 3 at the time of waiting and retained by a damper 1 supported by the armature stopper 19. A damper spacer 14 is constituted by laminating thin layers of polyimide or the like and assembled between the armature stopper 19 and the damper 1, and the waiting position of the armature 2 is adjusted by varying the number of layers and thicknesses. A damper protector 24 is a metal plate of petal shape and positioned between the damper 1 and the armature 2, and durability is improved by protecting the damper 1 from the impact given by the armature 2 at the time of resetting the armature 2.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a conventional technique, Japanese Patent Laid-Open No. 3-4535
A structure as shown in 2 was known. As shown in FIG. 6, this is done by connecting the outer peripheral end of the lever holder 113 to the yoke 11
5, the lever holder 113 is pressed by the fixed spring 118 toward the spring holder 120 to press the yokes 115 and 116. Here, in order to keep the stroke of the amateur 102 constant, it is necessary to bring the lever holder 113 and the spring holder 120 into contact with each other.
It is necessary to bring 13 into contact with the spring holder 130 and the yoke 115. Therefore, the spring holder 120 and the yoke 11 are formed by forming the lever holder 113 with a flexible material such as resin and bending it with a pressing force.
It was touching 5 at the same time.

[0003]

However, when the lever holder 113 is made of resin, creep occurs due to a temperature rise when the head is driven, the spring holder contact surface of the lever holder 113 is deformed, and the stroke of the armature 102 is reduced. The phenomenon that it changes during use occurs.
When the stroke of the armature 102 changes, the printing force becomes unstable to cause printing defects such as print density, or the response time changes to cause poor response, causing serious problems such as ribbon hooking and print wire breakage. To do. Further, the deformation of the contact surface of the lever holder 113 with the spring holder 120 due to creep also affects the yoke pressing force at the outer peripheral end of the lever holder. As a result, the yoke pressing force is reduced, and minute vibrations of the yokes 115 and 116 are generated, so that the armature 102 and the yokes 115 and 116 rub against each other, causing poor print head durability and abnormal noise.

[0004]

In order to solve the above-mentioned problems, the impact dot of the present invention has a coil which selectively energizes to generate a magnetic flux, and one end of which is engaged with a printing wire and is attracted by the coil to perform a printing operation. An amateur that performs the above, a yoke that constitutes a magnetic circuit together with the amateur, and a return spring that returns the amateur to the standby position after the printing operation ends,
In an impact dot head that has a spring holder that holds the return spring, an armature stopper that holds the armature at the standby position and at the same time contacts the spring holder, and a lever holder made of resin that holds the yoke It is characterized in that the armature stopper is made of metal while being in contact with the lever holder, and is pressed against the lever holder to bend the lever holder and press the yoke.

[0005]

Embodiments of the impact dot head of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view most accurately showing an embodiment of the impact dot head of the present invention.
It is a figure which shows the cross section in -i. 2 is a perspective view showing a state before assembly of the head of FIG. 1 showing an embodiment of the impact dot head of the present invention, and FIG. 3 shows a bending direction of a lever holder in the embodiment of the impact dot head of the present invention. FIG. 4 is a side view showing an embodiment of the impact dot head of the present invention, and FIG. 5 is a front view of the embodiment of the impact dot head of the present invention.

The wire guide 4 is held by a nose 22. The armature 2 to which the printing wire 5 is fixedly held by the wire guide 4 is fixed to the first yoke 1 by the fulcrum pressing spring 7 so as to be rotatable around the fulcrum 8.
6, the fulcrum position is held by being pressed by the frame 17 and the frame 17, and by the drive coil control means (not shown),
When the drive coil 6 is selectively energized under a predetermined drive condition, the print paper 11 is attracted to the core 9 and holds the print wire 5 on the platen 12 via the ink ribbon 10.
Hit on top.

The armature 2 is assembled so as to be pressed by the return spring 3 during standby and held by the damper 1 supported by the armature stopper 19.
The damper spacer 14 is formed by laminating thin sheets of polyester, polyimide, or the like, is assembled between the armature stopper 19 and the damper 1, and the standby position of the armature 2 is adjusted by changing the number and thickness of the damper. The damper protector 24 is a petal-shaped metal plate, is located between the damper 1 and the amateur 2, and protects the damper 1 from an impact given by the amateur 2 when the amateur returns to improve durability. The second yoke 15, the first yoke 16, the frame 17, and the core 9 are made of a magnetic material and form a magnetic circuit.

The fixing spring 13 is connected to the nose claw portion 23 and gives a fixing force to the amateur stopper 19. Reference numeral 20 is a spring holder.

The amateur stopper 19 is made of metal such as brass or aluminum for the purpose of preventing creep. In addition, when mounting the head, the fixed spring 1
By being pressed in the direction of the spring holder, the contact portion 8 contacts the spring holder convex portion 21 to determine the print stroke of the armature 2. The armature stopper 19 abuts the lever holder 13 at the portion shown in FIG. 3A, and the fixing spring 13 applies a force f to the lever holder 13 to push down the inner peripheral portion thereof toward the spring holder.

The lever holder 13 is made of resin and abuts the armature stopper 19 and the second yoke 15 at the outer end. Here, the lever holder 13 is bent in the direction of the arrow b from the shape shown by the dotted line in FIG.
The second yoke 15 and the first yoke 1 have a stable bending force f.
6 is fixed. The radiator 25 is made of aluminum, and is assembled so as to cover the head after assembly to radiate the heat generated during printing to the atmosphere.

In this embodiment, the lever holder 1
3 and the amateur stopper 19 are assembled at the time of assembling the head, but it is also possible to integrally form them in advance by outsert molding or the like. By doing so, the assembly process can be omitted and the cost can be reduced as compared with the case of being configured separately.

Further, in the present embodiment, the head having the one-stage frame structure has been described, but it goes without saying that this can also be applied to a head having a laminated structure in which the frames are stacked in two and three stages.

[0014]

As shown in the present invention, since the amateur stopper portion is formed of metal, it is possible to completely eliminate the creep of the amateur stopper. Therefore, it is possible to prevent the lever stroke from varying due to the creep of the amateur stopper, and to realize a print head with stable print quality. Also, by adopting a structure in which a metal armature stopper is pressed against the lever holder to bend the lever holder and press the yoke, the effect of creep on the spring holder contact surface of the lever holder, which has been a problem in the past, is eliminated. It is possible to fix the yoke with a stable fixing force. This makes it possible to prevent vibration of the yoke and realize a print head having excellent durability. Further, since the armature stopper is made of metal, the heat dissipation characteristic is improved and a print head capable of high duty printing can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view of an impact dot head according to an embodiment of the present invention.

FIG. 2 is a perspective view of an impact dot head according to an embodiment of the invention.

FIG. 3 is an explanatory diagram illustrating a bending direction of a lever holder of an impact dot head according to the present invention.

FIG. 4 is a side view showing an embodiment of impact dots of the present invention.

FIG. 5 is a front view showing an embodiment of the impact dot head of the present invention.

FIG. 6 is a sectional view of a conventional impact dot head.

[Explanation of symbols]

 1 Damper 2 Armature 3 Return Spring 4 Wire Guide 5 Printing Wire 6 Driving Coil 7 Support Point Holding Spring 8 Support Point 9 Core 10 Ink Ribbon 11 Printing Paper 12 Platen 13 Lever Holder 14 Damper Spacer 15 Second Yoke 16 First Yoke 17 Frame 18 Fixed Spring 19 Amateur stopper 20 Spring holder 22 Nose 102 Amateur 113 Lever holder 115 Yoke 116 Yoke 118 Fixed spring 120 Spring holder 130 Spring holder

Claims (1)

[Claims] 1. A coil that selectively energizes to generate a magnetic flux, an armature engaging one end with a print wire and attracted by the coil to perform a printing operation, and a yoke that forms a magnetic circuit together with the armature. A return spring that returns the armature to the standby position after the printing operation is completed, a spring holder that holds the return spring, an armature stopper that holds the armature at the standby position and simultaneously contacts the spring holder, and the yoke. In an impact dot head having a lever holder made of resin, the outer peripheral end of the lever holder is brought into contact with the yoke, the armature stopper is made of metal, and the lever holder is pressed to bend the lever holder. An in-circuit characterized by being configured to hold down the yoke. Pact dot head.