JPH05162341A - Dot impact printing head - Google Patents

Abstract

PURPOSE:To stabilize the operation of the armature of a dot impact printing head and to achieve high speed printing, the enhancement of quality, and productivity and cost reduction. CONSTITUTION:A fulcrum part 13 and a leaf spring 5 are arranged so that the center of rotation of an armature 1 becomes the end of a block 4 and a screw 14 is provided so as to adjust the bending quantity of the leaf spring 5. The impact center of the armature 1 is set to the vicinity of a printing wire 2 and an armature stopper 15 is provided at the position of said impact center. The armature stopper 15 is placed on a stopper holding member 16 and all of the contact surfaces of the stopper holding member 16, a yoke 6 and armature 1 are subjected to surface processing to obtain dimensional accuracy. By this constitution, the operation of the armature is stabilized and increased in speed and a printing head is made inexpensive and enhanced in quality.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a dot impact print head of this type has an arm 3 having a print wire 2 attached to its tip, a block 4 having the arm 3 attached thereto, and a block 4 attached thereto. A plurality of armatures 1 composed of leaf springs 5, a yoke 6 corresponding to each block 4 of each armature 1, a coil 7 mounted on the yoke 6, and a permanent magnet 8 installed on the outer peripheral portion of the yoke 6. And a ring yoke 9 stacked on the permanent magnet 8.
And a side magnetic path plate 10 and an upper magnetic path plate 11 sandwiching and fixing the leaf spring 5, and a head frame 12 mounting and fixing each component.

In the above construction, the block 4 is magnetically attracted to the yoke 6 by the magnetic flux of the permanent magnet 8 during non-printing, whereby the leaf spring 5 is bent.

When a current is applied to the coil 7 and the magnetic flux from the permanent magnet is canceled, the magnetic attraction force acting on the block 4 is also canceled and the armature 1 is rotated counterclockwise by the force of the deflected leaf spring 5. Printing is performed by the printing wire 2 attached to the tip.

Since the current is cut off again after printing, the magnetic flux of the permanent magnet 8 attracts the block 4 to the yoke 6 to return it to the non-printing state.

[0006]

In this conventional dot impact print head, as shown in FIG. 6, the armature rotation center 18 is located in the middle of the leaf spring 5, and the block 4 having a large mass is separated from the armature rotation center. Therefore, the moment of inertia of the armature 1 is large, and the armature impact center 1A is located near the joint between the block 4 and the arm 3.

As described above, since the armature 1 has a large moment of inertia, it becomes difficult to operate at high speed, and in order to speed up the operation, the spring constant of the leaf spring 5 is increased or the magnetic attraction force is increased accordingly. In addition, it is necessary to increase the current consumption, which makes it difficult to achieve high-speed printing, low power consumption, and low price.

Further, since the armature impact center position is separated from the printing wire 2, when the printing wire collides with the printing paper, the block 4 part overshoots and high-order vibration is generated in the armature 1 to cause the plate. The spring 5 and the arm 3 may be damaged, and the print wire 2 may be damaged.
There was a drawback that the contact time of the printing paper was long and the speed could not be increased.

It is an object of the present invention to provide a dot impact print head which stabilizes the armature operation of the print head and realizes high speed printing and high quality.

[0010]

In order to achieve the above object, in a dot impact print head according to the present invention, a plurality of magnetic circuits including a plurality of armatures and coils having print wires attached to their tips, and a magnetic circuit A print head having a spring that opposes a suction force and rotating an armature by a magnetic attraction force and a spring force to perform printing, wherein the spring is formed by a leaf spring, and one end thereof is fixed to the armature. The armature has a structure in which the end on the side where the leaf spring is attached is pressed against the fulcrum member and rotates around this end, and the leaf spring bends the end opposite to the armature by a certain amount. As a result, a force is generated in a direction opposite to the magnetic attraction force acting on the yoke and the armature.

Further, as a means for bending the leaf springs by a certain amount, each leaf spring has one screw, and the amount of bending can be adjusted separately for each leaf spring. After that, the screws are fixed with an adhesive. In addition, the leaf spring, strip-shaped ones are arranged in a circle for the number of armatures, and a thin joint is taken out from the rotation fulcrum portion of the armature in the rotation axis direction of the armature, so that all leaf springs are integrated, The connecting portion is sandwiched and fixed by the print head structural member.

The dot impact print head according to the present invention is a dot impact print head having a printing armature, the armature constituting a magnetic circuit, and a block for generating a magnetic attraction force by a yoke, and a block. It consists of a plate-shaped arm that is attached to and extends in the direction opposite to the center of rotation, and a printing wire that is attached to the tip of the arm. By bringing the block closer to the center of rotation, It has an impact center.

Further, in the print head having the armature structure, the armature stopper is provided on the side opposite to the print surface at the armature impact center position. In addition, the magnetic attraction surface of the armature and the armature stopper collision surface are on the same plane, and the magnetic attraction surface and the armature stopper surface of the yoke are higher on the armature stopper surface, and the difference in level is that of the step at the time of armature collision. Is it almost equal to the dent amount of the armature stopper,
It is less than that. Further, the armature stopper is attached to the stopper holding member, the stopper holding member is attached to the opposite side of the yoke from the magnetic attraction surface, and the thickness of the armature stopper is the same between the yoke and the stopper holding member. Alternatively, the spacer has a spacer thicker by the amount of depression when the armature collides with the armature stopper.

[0014]

The spring is formed of a leaf spring and has one end fixed to the armature. The armature has a structure in which the end on the side where the leaf spring is attached is pressed against the fulcrum member and rotates about this end. The leaf spring bends the end opposite to the armature by a certain amount to generate a force in the direction opposite to the magnetic attraction force acting on the yoke and the armature.

[0015]

The present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view of a dot impact print head according to an embodiment of the present invention, and FIG. 2 is a perspective view showing one of the armatures 1 of the dot impact print head shown in FIG.

As shown in FIG. 2, the armature 1 is composed of an arm 3 to which the print wire 2 is attached at the tip, a block 4 to which the arm 3 is attached, and a leaf spring 5 to which the block 4 is attached.

As shown in FIG. 3, in the leaf spring 5, strip-shaped leaf springs composed of an armature mounting portion 5D and a leaf spring bending portion 5C are arranged in a circle corresponding to the number of armatures, and the leaf spring connecting portion 5A and the leaf spring are fixed. The portion 5B has a structure in which all leaf springs are integrated.

Here, the end portion of the block 4 and the leaf spring connecting portion 5A are joined so as to coincide with each other, and the end portion of the block 4 is in contact with the fulcrum member 13 as shown in FIG. It is the center of rotation of the armature 1.

On the other hand, the leaf spring flexing portion 5C of the leaf spring 5 is bent by a screw 14 by a predetermined amount, and the block 4
Is applied in the direction of moving away from the yoke 6.

The yoke 6 is installed corresponding to the plurality of armatures 1, and the coil 7 is wound around it. A permanent magnet 8 is mounted on the outer peripheral portion of the yoke 6, and a ring yoke 9 is mounted thereon.

The leaf spring 5 is sandwiched and fixed to the fulcrum member 13 and the side magnetic path plate 10, and is attached to the head frame 12 together with the upper magnetic path plate 11 stacked thereon.

On the other hand, the center of rotation of the armature 1 is located at the end of the block 4, and the armature impact center 1A is arranged near the print wire 2.
An armature stopper 15 made of rubber is installed under A, and the armature stopper 15 is mounted on a stopper holding member 16 mounted by sandwiching a spacer 17 between the armature stopper 15 and the yoke 6.

Here, the contact surface of the block 4 with the yoke 6 and the contact surface of the arm 3 with the armature stopper 15 are machined so as to be flush with each other. The stopper holding member 16 is attached to the yoke 6 with the spacer 17 removed, and the spacer 17 and the armature stopper 15 are attached after the armature stopper 15 attachment surface is machined into the same plane as the block 4 contact surface of the yoke 6.

The spacer 17 serves as the armature stopper 1.
The thickness of the armature stopper 1 is equal to the thickness of the armature stopper 5, or is thicker than the thickness of the armature stopper 15 when the arm 3 collides with the armature stopper 15.
The surface of 5 is the same as the surface of the yoke 6 that contacts the block 4, or is set higher than that by the amount of the depression.

In the above construction, the principle of printing operation is the same as that of the above-mentioned conventional print head, but the screw 14 can adjust the force of the leaf spring with respect to the magnetic attraction force. Since the rotation center of the armature 1 is close to the block 4, the moment of inertia is small.

On the other hand, since the armature impact center position is close to the printing wire 2, the armature 1 is not deformed by inertia even when the printing wire 2 collides with the printing paper.
Higher-order vibration does not occur.

Further, since the armature impact center position 1A is set so as to collide with the armature stopper 15, even when the armature 1 returns after printing, there is no deformation or rebound and stable printing operation is performed.

[0028]

As described above, according to the present invention, the shape of the leaf spring and the shape of the armature are configured such that the center of rotation of the armature is at the end of the block. Therefore, the moment of inertia of the armature operating portion can be reduced and the impact can be reduced. Since the center position can be brought close to the print wire, the printing speed is fast, and the high-order vibration of the armature is small, a highly reliable print head can be provided.

Further, the force of the leaf spring can be adjusted with a screw,
Since the armature stopper position can be easily and accurately set by the spacer, an inexpensive and high-quality print head can be provided.

On the other hand, since the armature impact center position and the armature stopper position coincide with each other, it is possible to provide a high-speed print head with stable armature operation and less obstacles.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a print head according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an armature of the print head shown in FIG.

3 is a perspective view showing a leaf spring of the print head shown in FIG. 1. FIG.

4 is a perspective view showing a side magnetic path plate of the print head shown in FIG.

5 is a perspective view showing a fulcrum member of the print head shown in FIG. 1. FIG.

FIG. 6 is a half sectional view showing a conventional print head.

[Explanation of symbols]

 1 Armature 2 Printing Wire 3 Arm 4 Block 5 Leaf Spring 6 Yoke 7 Coil 8 Permanent Magnet 13 Support Point Member 14 Screw 15 Armature Stopper 16 Stopper Holding Member 17 Spacer

Claims (7)

[Claims] 1. A plurality of magnetic circuits including a plurality of armatures and coils each having a print wire attached to its tip, and a spring that opposes the attraction force of the magnetic circuits, and the armature is rotated by the magnetic attraction force and the spring force. A print head for performing printing by using a leaf spring, the one end of which is fixed to an armature, the armature being pressed against a fulcrum member at the end on the side where the leaf spring is attached. The leaf spring generates a force in the direction opposite to the magnetic attraction force acting on the yoke and armature by bending the end opposite to the armature by a certain amount. Dot impact print head featuring. 2. As a means for bending the leaf spring according to claim 1 by a certain amount, each leaf spring has one screw, and each leaf spring can be adjusted in bending amount separately. The dot impact print head according to claim 1, wherein the screw is fixed by an adhesive after adjustment. 3. The leaf spring according to claim 1, wherein strip-shaped ones are arranged in a circle corresponding to the number of armatures, and a thin joint is provided from a rotation fulcrum portion of the armature in a rotation axis direction of the armature, 2. The dot impact print head according to claim 1, wherein the leaf spring is integrally formed, and the connecting portion is sandwiched and fixed by a print head structural member. 4. A dot impact print head having a printing armature, wherein the armature is a block which constitutes a magnetic circuit and generates a magnetic attraction force by a yoke, and which is attached to the block and extends in a direction opposite to a rotation center. It is composed of a plate-shaped arm and a printing wire attached to the tip of the arm. By bringing the block closer to the rotation center, the dot impact is characterized by having the impact center at the tip of the arm (near the wire attachment part). Print head. 5. A dot impact print head having the armature structure according to claim 4, further comprising an armature stopper on the side opposite to the print surface at the armature impact center position. 6. The dot impact print head according to claim 5, wherein the armature magnetic attraction surface and the armature stopper collision surface are flush with each other, and the yoke magnetic attraction surface and the armature stopper surface are armature stoppers. The dot impact print head is characterized in that the surface is higher and the step is approximately equal to or less than the dent amount of the armature stopper at the time of armature collision. 7. The print head according to claim 6, wherein the armature stopper is attached to a stopper holding member, and the stopper holding member is attached to a side of the yoke opposite to the magnetic attraction surface. A dot impact print head having a spacer between the members, the spacer having a thickness equal to or greater than the thickness of the armature stopper, or thicker than the armature stopper by a dent amount when the armature collides with the armature stopper.