JPH04294159A - Impact dot head - Google Patents

Abstract

PURPOSE:To stabilize the behavior of a lever, and to improve printing quality by inclining and arranging a return spring in a fixed quantity to the axial line of a head. CONSTITUTION:In an impact dot head with a lever 10 having a printing wire 7, a support member 8 supporting said lever 10, a return spring 1 returning said lever 10 and a holder 13 holding said return spring 1, said return spring 1 is tilted and disposed in a fixed quantity to the axial line Z of the impact dot head.

Description

[Detailed description of the invention]

0001

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

0002

2. Description of the Related Art As shown in FIG. 4, a return spring A of a conventional impact dot head is arranged parallel to an axis Z of the impact dot head.

[0003] In the printing process, when the lever C having the printing wire B is attracted, the lever C is supported by the support member E and rotates with the lever fulcrum Ca as a fulcrum. The lever fulcrum portion Ca is elastically held by a fulcrum presser spring D, and the spring force of the fulcrum presser spring D is set to such a level that the parts stacked in the axial center line Z direction do not creep. In addition, the printing wire B is attached to the fixed part B by brazing the lever C.
The structure is such that the stress applied to the fixed portion Ba becomes compressive stress so that the fixed portion Ba is fixed at point a and does not break even if printing is repeated. Therefore, the force acting on the lever C in the direction perpendicular to the axis Z is the force received from the fulcrum presser spring D in the direction of the axis Z, and the force in the direction opposite to the axis caused by the bending force of the printing wire B. It becomes the resultant force. This resultant force has a value close to zero for the reasons mentioned above, and due to variations in the spring force of the fulcrum presser spring A and the printing wire B and lever C.
Due to variations in the bending force of the printing wire B depending on the fixing angle of the
The lever C moves away from the position where it should be in contact with the support member E on the plane perpendicular to the axis Z, resulting in unstable behavior and problems such as ribbon catching, missing dots, and other printing defects.

0004

The problem to be solved is that the behavior of lever C becomes unstable, resulting in printing defects such as missing dots and ribbon catching.

[0005]

[Means for Solving the Problems] In order to stabilize the behavior of the lever, the impact dot head of the present invention includes a lever having a printing wire, a support member that supports the lever, and a return spring that returns the lever. In the impact dot head having a holder for holding the return spring, the return spring is tilted by a predetermined amount with respect to the axis of the impact dot head.

[0006]

[Embodiment] FIGS. 1 and 2 are diagrams showing an embodiment of the present invention. A frame 6 having a plurality of cores 5 has a predetermined number of coils 11 incorporated therein, and a lever 10 is printed on the inner circumference of the frame 6. A holder 13 having a return spring 1 for returning after completion is incorporated. On the outer periphery of the frame 6,
A recess corresponding to each lever 10 is provided on the outer periphery of the ring-shaped plate material, and a support member that supports the lever 10 is in contact with a yoke 8 that constitutes a part of the magnetic circuit. The side yoke 9 has a shape that holds the lever 10 between a predetermined number of grooves, and cooperates with the yoke 8 to form part of a magnetic circuit.

A printing wire 7 is fixed to one end of the lever 10, and the lever fulcrum portion 10a is pressed by a fulcrum presser spring 2. The fulcrum presser spring 2 is composed of an elastically deformable spring part and a connecting part, and is assembled so as to come into contact with the back stopper 4. The back stopper 4 is
It has a damper 12 for absorbing energy when the lever 10 returns, and is further assembled to the nose 16 with a fixed spring 15 via a reinforcing plate 14.

The return spring 1 is arranged inclined by a predetermined amount α with respect to the axis Z of the impact dot head, and when the return spring force is F, a component force a (a=F sin α) is generated in the Y direction. However, the surface 10b of the lever 10 acts in a direction in which it comes into contact with the surface 8a of the yoke 8, which is the supporting member of the lever 10. On the other hand, the component force b in the Y direction of the fulcrum presser spring 2 is equal to the component force a described above.
In the same direction, the lever 10 acts in the direction of contacting the yoke 8. In addition, in order to ensure durability in repeated printing, the position of the guide hole of the wire guide section 3 of the holder 13 and the shape of the lever 10 are set so that compressive stress is applied to the fixed part 7a of the lever 10 and the printing wire 7. ing. The Y-direction component c of the bending force of the printing wire 7 is opposite to the aforementioned component a, and acts in the direction in which the lever 10 moves away from the yoke 8. Therefore, the resultant force e in the Y direction acting on the lever 10
becomes e=a+b−c.

When the coil 11 is driven, a magnetic circuit is formed by the frame 6 having the core 5, the yoke 8, the side yoke 9, and the lever 10, and the lever 10 uses the fulcrum part 10a as a fulcrum due to the magnetic attraction force, and the yoke 8 abuttingly supported;
The printing wire 7 fixed to one end of the lever 10 connects the printing paper (
(not shown) until it collides with a platen (not shown), forming dots on the print paper. After printing is finished,
The lever 10 having the printing wire 7 returns due to the repulsive force from the platen (not shown) and the spring force of the return spring 1, and the energy of the return stroke is absorbed by the damper 12.
It is held in the standby position.

In the above series of operations, the position of the lever 10 in the Y direction is determined by the aforementioned resultant force e in the Y direction, and the resultant force e is the aforementioned component force a of the return spring 1 and component force b of the fulcrum presser spring 2. It is determined by the component force c of the bending force of the printing wire 7. The fulcrum presser spring force is set so that the backstopper 4 supporting the fulcrum presser spring 2 does not creep, and the relationship between the component force b of the fulcrum presser spring 2 and the component force c of the bending force of the printing wire 7 is b>c. However, the difference between component force b and component force c is small. As the bending angle β of the spring portion of the fulcrum presser spring 2 varies, the amount of deflection when it comes into contact with the lever 10 varies, and the spring force varies. When the bending angle β is large, the component force b becomes small. Also, printing wire 7 and lever 1
The variation in the bending force of the printing wire 7 due to the fixing angle γ of 0 is caused by positional deviation when fixing the printing wire 7 and the lever 10. Due to these variations, when the return spring 1 is arranged parallel to the axis Z as in the conventional case, the component force a of the return spring 1 in the Y direction does not act, and the resultant force e becomes negative.
The lever 10 is moved until the Y-direction component c of the bending force of the printing wire 7 decreases and the resultant force e becomes e=0.
It moves in the -Y direction from the original position where it should come into contact with the yoke 8 that supports it.

However, in the impact dot head of the present invention, the component force a in the Y direction of the return spring 1 and the fulcrum presser spring 2
The return spring 1 is moved by a predetermined amount α with respect to the axis Z so that the component force b in the Y direction of the bending force of the printing wire 7 and the component force c in the Y direction of the bending force of the printing wire 7 satisfy a>(c-b). Because it is arranged at an angle,
Y to press the lever 10 from the return spring 1 in the axis center line Z direction
A component force a in the direction is generated, and due to variations in the parts that make up the impact dot head, a component force b of the fulcrum holding spring 2 is generated.
Even if the relationship between the component force c of the bending force of the printing wire 7 is b<c, the resultant force e can be made to be e>0 (e=a+b−c). Therefore, the force that presses the lever 10 to the position where it abuts the support member yoke 8 of the lever 10 can be constantly applied, and the behavior of the lever 10 is stable, and an impact dot head without printing defects such as missing dots or ribbon catching can be realized. realizable.

FIG. 3 shows an embodiment in which the holder 13 is divided into three parts, for example, the wire guide part 3, the holder A17, and the holder B18.The holder B18 is assembled to the holder A17, and the return springs are connected by semi-cylindrical shapes 17a and 18a. A cylindrical portion supporting 1 is formed. Next, the wire guide part 17 having the guide hole 22 for the printing wire 7 and serving as a spring receiving part for the return spring 1 is attached to the positioning protrusion 20 of the holder A17 in the positioning hole 21 of the wire guide part 3. Three parts, the guide part 3, the holder A17, and the holder B18, are integrated. The integrated holder 13 is positioned and assembled to the lever holder 4 by the protrusion 19.

In this way, in order to mold the holder 13 that supports the return spring 1 at a predetermined angle α with respect to the axis Z of the impact dot head as a single piece, a mold for the insertion groove of the return spring 1 is used. It is necessary to create a structure that slides at an angle of a predetermined amount α, which complicates the mold and increases processing costs.
By making the holder 13 have a split structure, it can be molded with a simple mold, reducing processing costs, achieving an inexpensive impact dot head with stable behavior of the lever 10 and no printing defects such as missing dots or ribbon catching. can.

[0014]

As described above, the impact dot head of the present invention includes a lever having a printing wire, a support member that supports the lever, a return spring that returns the lever, and a holder that holds the return spring. However, since the return spring is tilted by a predetermined amount with respect to the axis of the impact dot head, the lever behavior is stabilized and printing defects such as missing dots and ribbon catching can be solved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a detailed partial cross-sectional view showing an embodiment of the invention.

FIG. 3 is a partial perspective view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing a conventional example.

[Explanation of symbols]

1 Return spring 2 Fulcrum holding spring 3 Wire guide part 4 Back stopper 5 Core 6 Frame 7 Printing wire 8 York 9 Side yoke 10 Lever 10a Lever fulcrum part 13 Holder 17 Holder A 18 Holder B

Claims (1)

[Claims] 1. An impact dot head having a lever having a printing wire, a support member supporting the lever, a return spring returning the lever, and a holder holding the return spring, wherein the return spring is connected to the impact dot. An impact dot head characterized by being tilted by a predetermined amount with respect to the axis of the head.