JPH04310752A - Impact dot head - Google Patents

Abstract

PURPOSE:To reduce the abrasion of a guide aperture and improve the durability by making a sectional form of a head of the guide aperture for guiding a print wire in the direction of shaft line curved. CONSTITUTION:An impact dot head comprises a print wire 7 and a wire guide 1 for guiding the print wire 7. A sectional form of the impact dot head of a guide aperture 2 for guiding the print wire 7 of the wire guide 1 in the direction of shaft line Z is made to be curved. The wire guide 1 is constituted of a plurality of parts.

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, in a conventional impact dot head, the cross-sectional shape of the guide hole C that guides the printing wire B of the wire guide A in the direction of the axis center line Z of the impact dot head is a straight line. It had a unique structure.

[0003] In general, impact dot heads are capable of high speed,
In order to realize compactness due to high integration, the printing wire B and lever D are fixed and integrated into a structure. In the printing process in which dots are formed on printing paper (not shown) using the printing wire A, when the lever D is sucked, the lever D rotates around the lever fulcrum Da, and the printing wire B fixed to the lever D is rotated. The wire guide A converts rotational motion into linear motion to perform printing, and returns after printing is completed. Therefore, the side of the printing wire B that is fixed to the lever D is restrained by the fixed part to the lever D and the wire guide A, and the printing wire B is bent and guides the printing wire B of the wire guide A during repeated printing. Guide hole C
There was a problem that the wear of the printing wire B became large, the bonding part between the printing wire B and the lever D was broken, the printing wire B was broken, and the durability was significantly reduced.

0004

[Problems to be Solved by the Invention] The problem to be solved is that the fixed part of the printing wire B and the lever D is broken due to excessive wear of the guide hole C that guides the printing wire B of the wire guide A, and the printing wire B is damaged. This is the point where durability is significantly reduced due to breakage, etc.

[0005]

Means for Solving the Problems In order to improve durability, the impact dot head of the present invention has a printing wire and a wire guide for guiding the printing wire. A feature is that the guide hole for guiding the wire has a curved cross-sectional shape in the axial direction of the impact dot head. Further, the wire guide is characterized in that it is composed of a plurality of parts.

[0006]

[Embodiment] FIGS. 1 and 2 are diagrams showing an embodiment of the present invention, in which a predetermined number of coils 11 are incorporated into a frame 6 having a plurality of cores 5, and a lever 10 is printed on the inner circumference of the frame 6. A holder 1 having a return spring 13 for returning to the original position afterward is incorporated. A recess corresponding to each lever 10 is provided on the outer periphery of a ring-shaped plate on the outer periphery of the frame 6, and a yoke 8, which is a support member that supports the lever 10 and forms part of a magnetic circuit, is in contact with the outer periphery of the frame 6. . 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 a lever fulcrum portion 10a is pressed by a fulcrum presser spring 3. The fulcrum presser spring 3 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 has a damper 12 for absorbing energy when the lever 10 returns, and is further assembled to the nose 16 by a fixed spring 15 via a reinforcing plate 14. The lever 10 side of the printing wire 7 fixed to the lever 10 by brazing or the like is guided by a wire guide 1 described below. The guide hole 2 for guiding the printing wire 7 of the wire guide 1 is configured such that its cross-sectional shape in the direction of the axis Z of the impact dot head is a curve.

Further, as shown in FIG. 2(a), when the impact dot head is in a standby state, the lever 10 of the printing wire 7
A force in the -Y direction is applied to the side fixed to the lever 10, and a compressive stress acts on the fixed part of the printing wire 7 to the lever 10. The printing wire 7 is attached to the surface 2 of the guide hole 2 of the wire guide 1.
a, and is guided by an intermediate guide 17 having a tapered portion on the insertion side of the printing wire 7 to improve assembly ease. The shape of the surface 2a of the guide hole 2 of the wire guide 1 in the axial center line Z direction of the impact dot head is formed, for example, by a curve that is approximately the same shape as the bending curve of the printing wire 7. On the other hand, as shown in FIG. 2(b), when the impact dot head is in the suction state, a force in the +Y direction is applied to the side of the printing wire 7 that is fixed to the lever 10, and a force is applied to the side of the printing wire 7 that is fixed to the lever 10. Tensile stress acts on . The printing wire 7 is attached to the surface 2b of the guide hole 2 of the wire guide 1.
The printing wire 7 is bent by the intermediate guide 17, which has a tapered portion on the insertion side of the printing wire 7 to improve assembly efficiency. The shape of the surface 2b of the guide hole 2 of the wire guide 1 in the axial center line Z direction of the impact dot head is formed, for example, by a curve approximately the same shape as the bending curve of the printing wire 7.

Next, the operation will be explained. 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 rotates about the fulcrum portion 10a due to the magnetic attraction force. By rotating this lever, the printing wire 7 fixed to one end of the lever 10 is inserted into the guide hole 2 of the wire guide 1.
The rotational motion is changed into a linear motion, and the printing paper (not shown) is driven in the direction of the printing paper (not shown).
until it collides with the platen (not shown) through the
Form dots on printing paper. After printing is completed, the lever 10 having the printing wire 7 returns to its original position due to the repulsive force from the platen (not shown) and the spring force of the return spring 13, absorbs the energy of the return process by the damper 12, and returns to the standby position. Retained.

In the above series of operations, when the printing wire 7 moves from the standby position to the suction position, the bending curve of the printing wire 7 changes due to the rotation of the lever 10, and the bending curve of the printing wire 7 changes from the printing wire 7 to the guide hole 2 of the wire guide 1. Bending force acts. However, in the impact dot head of the present invention, the cross-sectional shape of the guide hole 2 of the wire guide 1 in the axial center line Z direction of the impact dot head is curved, so in order to change the printing wire 7 from rotational motion to linear motion, It becomes possible to enlarge the surface of the guide hole 2 of the wire guide 1 which receives the bending force from the printing wire 7 and guides the printing wire 7.

[0010] Therefore, even in repeated printing of hundreds of millions of strokes, wear of the guide hole 2 that guides the printing wire 7 of the wire guide 1 can be reduced, and an impact dot head with significantly improved durability can be realized.

FIG. 3 shows an embodiment in which the wire guide 1 is composed of two parts, for example, a wire guide A18 and a wire guide B19.The wire guide A18 has a positioning protrusion 20, and the wire guide B19 has a positioning hole 21. The guide hole 2 that guides the printing wire 7 is formed by the semi-curved cylindrical portions 18a and 19a of the wire guide A 18 and the wire guide B 19, and the cross-sectional shape in the axial center line Z direction of the impact dot head is curved. It is assembled so that
It integrates two parts.

As described above, the wire guide 1 whose cross-sectional shape in the direction of the axial center line Z of the impact dot head of the guide hole 2 that guides the printing wire 7 is curved is made into multiple parts of the wire guide A 18 and the wire guide B 19. Since it has a structure that can be integrated by dividing and assembling, it is possible to easily manufacture an impact dot head that is inexpensive and has significantly improved durability.

[0013]

As described above, the impact dot head of the present invention has a printing wire and a wire guide that guides the printing wire, and the axis of the impact dot head of the guide hole that guides the printing wire of the wire guide. Since the cross-sectional shape in the direction of the core wire is curved, the surface that guides the printing wire in the guide hole of the wire guide, which receives the bending force from the printing wire, can be enlarged, and the guide hole will remain stable even during repeated printing over hundreds of millions of strokes. This reduces wear and tear, and solves durability problems such as breakage of the fixed part of the print wire and lever, and breakage of the print wire.

[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 detailed partial sectional view showing a conventional example.

[Explanation of symbols]

1 Wire guide 2 Guide hole 3 Fulcrum holding spring 4 Back stopper 5 Core 6 Frame 7 Printing wire 8 York 9 Side yoke 10 Lever 10a Lever fulcrum part 13 Return spring 17 Intermediate wire guide 18 Wire guide A 19 Wire guide B

Claims (2)

[Claims] 1. An impact dot head having a printing wire and a wire guide for guiding the printing wire, wherein a cross-sectional shape in the axial direction of the impact dot head of a guide hole for guiding the printing wire of the wire guide is curved. An impact dot head characterized by: 2. The impact dot head according to claim 1, wherein the wire guide is composed of a plurality of parts.