JP2567479Y2 - Wire dot print head - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a wire dot print head in a serial printer.

[0002]

2. Description of the Related Art FIG. 5 is a schematic sectional view of a spring-charge type wire dot print head in a conventional serial printer. This print head has a base 3 on which a substrate 2 is attached via a spacer 1 made of insulating rubber packing or the like on the back surface, a first yoke 4, a permanent magnet 5, and a second It comprises a yoke 6, a leaf spring 7 for bias, a spacer yoke 8, an armature yoke 9, and the like.

More specifically, the permanent magnet 5 is disposed on the outer edge of the base 3 so as to be interposed between the first yoke 4 and the second yoke 6, and the first yoke 4 and the second
It is fixed together with the yoke 6 by a screw 12.

[0004] The second yoke 6 is generally formed in a substantially ring disk shape. A ring-shaped projection 6a for holding the leaf spring 7 with the spacer yoke 8 therebetween is formed integrally with the outer edge of the surface facing the leaf spring 7, and the projection 6a is formed on the inner edge. A ring-shaped fulcrum 6b protruding in the same direction toward the same direction by an amount substantially equal to the height is integrally formed.

The leaf spring 7 includes a ring-shaped main body 7a which is sandwiched and fixed between the projection 6a of the second yoke 6 and the spacer yoke 8, and a leaf spring from the inner side of the main body 7a by the number of print wires 11. A plurality of flexible portions 7b each protruding toward the center of 7 are provided integrally at substantially equal intervals. 6, a notch hole 17 is provided at a substantially central portion of each flexible portion 7b, and a tongue-like shape is formed from the distal end side of the flexible portion 7b toward the main body portion 7a. Wing piece 7
c is integrally formed in a state extended into the cutout hole 17. On the tongue-shaped wing 7c of each flexible portion 7b, an armature 10 having a print wire 11 attached to its tip is mounted, and is fixedly attached by spot welding or the like.

On the base 3, cores 14, each of which has a coil 13 wound on the peripheral surface thereof, are mounted on the lower side of the armature 10.
The three lead terminals 15 are respectively connected by soldering to a circuit (not shown) on the substrate 2.

Further, a wear-resistant magnetic metal sheet 16 is arranged on the core 14 so as to partially extend over the pivot 6b of the second yoke 6.

The armature yoke 9 is formed in a ring shape and provided on the spacer yoke 8. in addition,
On the inner peripheral surface side of the armature yoke 9, teeth 9 a are formed in a number corresponding to the number of the armatures 10 so as to surround each armature 10 from both sides and protrude toward the center.

Next, the operation of the wire dot print head will be described. First, in this wire dot print head, the magnetic flux of the permanent magnet 5 is applied to the first yoke 4, base 3,
Core 14, leaf spring 7, armature 10, armature yoke 9, spacer yoke 8, leaf spring 7, second yoke 6
A magnetic circuit is formed which returns to the permanent magnet 5 again through the magnet.

Accordingly, when the coil 13 is not energized, the armature 10 is attracted to the core 14 by the magnetic flux of the permanent magnet 5, and the rotation fulcrum 6b is connected to the armature rotation center 18 of the leaf spring 7 (see FIG. 6). The tongue-shaped wing piece 7c is brought into contact with the core 14 via the magnetic metal sheet 16 with the portion of the contacted armature rotation center 18 as a fulcrum.
The armature 10 is rotated together with the tongue-shaped wing piece 7c until the armature 10 comes into close contact with the front end surface of the flexible portion 7c, and is held in a state where the flexible portion 7b is deformed. The printing wire 11 is drawn into a guide frame (not shown) by this suction, and is in a standby state.

On the other hand, at the time of printing, a short-time current is applied to the coil 13 from the substrate 2 side to excite it. Then
During this excitation, the magnetic flux of the permanent magnet 5 is canceled out, and the force attracting the armature 10 disappears. When the suction force is lost, the flexible portion 7b of the leaf spring 7, which has been held in a state of being bent up to that point, is moved around the armature rotation center 18 (see FIG. 6) as a fulcrum. Armature yoke 9 with rotation return of 7c
Move with the armature 10 to the side. Then, the printing wire 11 fixedly attached to the tip of the armature 10 protrudes from the guide frame, and presses an ink ribbon and a printing medium (not shown) against the platen. Thereby, characters, graphic patterns, and the like can be printed. After the impact operation, the armature 10 is sucked and held on the core 14 together with the flexible portion 7b.

In today's printers, higher-speed and higher-quality printing is required. In order to respond to this demand, for example, a method of storing a strong force in the leaf spring 7 and releasing it in a short time, a method of reducing the inertial mass of the driving portion, and the like are conceivable.

[0013]

However, in the above-described conventional structure, a part of the flexible portion 7b of the leaf spring 7 is disposed on the core 14 so as to overlap with the armature 10. It is placed in a magnetic path for suction. For this reason, when the thickness of the leaf spring 7 is increased, the magnetic properties of the spring material are generally lower than those of other magnetic materials. Therefore, the magnetic resistance is increased and the flow of the magnetic flux is obstructed, and the armature 10 is attracted. I will not be able to cut it. The portion inside the fulcrum (the armature rotation center 18) where the leaf spring 7 rotates together with the armature 10 has no function as a spring and merely contributes to an increase in the mass of the driving portion.

The present invention has been made in view of the above points, and an object of the present invention is to provide a print head having an improved joint structure between an armature and a leaf spring and having excellent high-speed response.

[0015]

In order to achieve the above object, a wire dot print head according to the present invention is provided at a free end side of a flexible portion protruding toward the center from a main body portion to which a leaf spring is fixed. The armature having a print wire attached to the distal end is fixed to the base end side, and the armature is magnetically attracted to the core side together with the flexible portion by using a pivot point provided between the main body and the core as a fulcrum. The flexible portion is rotated and held in a state of storing the bending energy,
In a wire dot print head in which the magnetic attraction is released during a printing operation and the printing wire is made to perform an impact operation by releasing the stored bending energy of the flexible portion, a connection between the free end of the flexible portion and the armature A position is set closer to the main body portion than a position directly above the core, and a lower surface of the armature is provided with a step corresponding to a thickness of the leaf spring by cutting the lower surface from a base end,
A configuration is adopted in which the free end of the flexible portion is brought into close contact with and fixed to the step. Further, in the present invention, a configuration is adopted in which the armature is provided at a predetermined angle with respect to the flexible portion in a direction in which a distal end side of the armature is separated from the surface of the core.

[0016]

According to this structure, the joint between the free end of the flexible portion and the armature is set closer to the main body than the position directly above the core. That is, the structure is such that it does not go directly above the core. As a result, even if the thickness of the leaf spring is increased to obtain a strong spring force, a decrease in suction force and an increase in inertial mass do not occur. In addition, a step corresponding to the thickness of the leaf spring is provided on the lower surface of the armature, and the free end of the flexible portion is fixed to the portion of the step by closely contacting the free end, so that the leaf spring and the armature are on the lower surface side of the armature. It will be flush. This allows you to adjust the height separately for other components,
It becomes possible to store the bending energy in the flexible portion of the leaf spring by attracting the armature to the core. Further, in the notch formed on the lower surface of the armature, a surface where the leaf spring is in close contact is formed at an angle, and the armature is fixed to the leaf spring in a state where the leaf spring and the armature are in close contact with each other. The tilting angle of the armature makes it possible to store the bending energy in the leaf spring in a state where the armature is attracted to the core, without forming the rotating fulcrum part in a protruding shape as in the related art. .

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 show a wire dot print head according to an embodiment of the present invention. FIG. 1 is a schematic sectional view, FIG. 2 is an enlarged perspective view of a main part thereof, and FIG. It is. 1 to 3, FIG.
6 and 7 indicate the same components as those in FIGS. 5 and 6.

The major difference between the conventional print head shown in FIGS. 5 and 6 and the print head of this embodiment lies in the joint structure between the armature 10 and the leaf spring 7, and the like.
Others have almost the same structure. Therefore, in the following description, the duplicated description of the parts configured with the same structure as in FIGS. 5 and 6 will be omitted, and the description will focus on the differences.

In the print head shown in FIGS. 1 to 3, the leaf spring 7 is sandwiched and fixed between the projection 6a of the second yoke 6 and the spacer yoke 8 and is integrally formed toward the center from the body 7a. The flexible portion 27b has its free end 2
7d is in contact with the pivot point 6b via the magnetic metal sheet 16, and can receive the rotational reaction force at this contact portion, as well as in the magnetic path of the attracted magnetic flux by the permanent magnet 5,
That is, in order to prevent the flow of the magnetic flux from being hindered immediately above the core 14, the magnetic flux is not extended to just above the core 14, but is extended to a position above the rotation fulcrum 6b and is stopped. . A cutout hole 17 is formed at a substantially central portion of the flexible portion 27b.
A tongue-shaped wing 27c is formed integrally with the free end 27d of the base 7b so as to extend into the cutout hole 17 toward the main body 7a.

On the other hand, the armature 10 attached to the flexible portion 27b of the leaf spring 7 is provided with a cutout corresponding to the thickness of the leaf spring 7 on the lower surface on the base end side. Is formed. The flexible portion 27 of the leaf spring 7 is provided in the step 21.
The free end 27d and a part of the tongue-shaped wing piece 27c are brought into contact with the armature 10 in close contact with each other, and the contact part is fixed by laser welding or the like. Here, the above-mentioned step 21 is formed between the free end 7d of the flexible portion 7b and the armature 10
In this embodiment, a step 21 is formed.
(Joining portion) is set closer to the main body portion 7a than the position immediately above the core 14, more specifically, between the rotation fulcrum portion 6b and the core 14.

In this embodiment, since the step 21 corresponding to the thickness of the leaf spring 7 is formed at the base end of the armature 10, in the state where the leaf spring 7 and the armature 10 are fixed as described above, On the lower surface side of the armature 10, the leaf spring 7 and the armature 10 are flush. This is because, in the print head of the present embodiment, a step is formed between the rotation fulcrum 6b and the projection 6a of the second yoke 6 fixing the leaf spring 7, and the armature 10 is sucked by the core 14. This is because bending energy is stored in the flexible portion 27b of the leaf spring 7 in this state.

That is, if there is a level difference between the lower end surface of the armature 10 and the lower end surface of the leaf spring 7, the upper surface of the core 14 and the upper surface of the rotation fulcrum 6b are adjusted in accordance with the level difference. This makes it necessary to adjust the difference in height between the second yoke 6 and the projection 6a, which makes it extremely difficult to manufacture a print head.

The wire dot print head thus configured also operates in substantially the same manner as the print head shown in FIGS. Then, the operation of the print head in this embodiment will be described below. First, in this wire dot print head, the free end 27d of the flexible portion 27b of the leaf spring 7 is
, The magnetic flux of the permanent magnet 5
A magnetic circuit that returns to the permanent magnet 5 through the yoke 4, the base 3, the core 14, the armature 10, the armature yoke 9, the spacer yoke 8, the leaf spring 7, and the second yoke 6 is formed. That is, between the core 14 and the armature 10. A magnetic circuit is formed without the leaf spring 7 interposed in the magnetic path of the attracted magnetic flux.

Thus, when the coil 13 is not energized, the armature 10 is attracted to the core 14 by the magnetic flux of the permanent magnet 5, and the armature rotation center 18 (FIGS. 2 and 3) of the leaf spring 7 is The armature 10 is in close contact with the tip surface of the core 14 through the magnetic metal sheet 16 together with the tongue-shaped wing 27c with the contacted portion of the armature rotation center 18 as a fulcrum. And is held in a state where the flexible portion 27b is deformed. The printing wire 11 is drawn into a guide frame (not shown) by this suction, and is in a standby state.

On the other hand, at the time of printing, a current is supplied to the coil 13 from the substrate 2 for a short time to excite it. Then
During this excitation, the magnetic flux of the permanent magnet 5 is canceled out, and the force attracting the armature 10 disappears. When the suction force is lost, the flexible portion 27b of the leaf spring 7, which has been held in a state of being bent up to that point, is moved around the armature rotation center 18 (see FIGS. 2 and 3) as a fulcrum. The armature 10 moves together with the armature 10 toward the armature yoke 9 with the return of the rotation of the wing 27c. Then, the printing wire 11 fixedly attached to the tip of the armature 10 protrudes from the guide frame, and presses an ink ribbon and a printing medium (not shown) against the platen. Thereby, characters, graphic patterns, and the like can be printed. Further, after the impact operation, the armature 10 is moved to the core 1 in a state where the flexible portion 27b is bent.
4 is again held by suction.

As described above, according to the wire dot print head of this embodiment, the joint (the step 21) between the free end 27d of the flexible portion 27b and the armature 10 is formed by the core 14
Fulcrum 6 closer to body 7a than directly above
b and the core 14, the plate spring 7 has a structure in which a part of the plate spring 7 does not wrap around the magnetic path portion and the driving portion of the attracted magnetic flux, that is, just above the core 14. And a strong plate spring 7 having a large plate thickness can be employed without causing a decrease in the inertia mass and an increase in the inertial mass. This allows
The high-speed response can be improved by using the strong spring force of the leaf spring 7.

According to the experiment, if the structure in which the leaf spring is not interposed in the magnetic path of the attracted magnetic flux as in the present embodiment, the attraction force is about 10 times that of the conventional structure in which the leaf spring is interposed.
%, And the inertial mass of the driving part is reduced by about 15%.

FIG. 4 is an enlarged side view of a main part showing a modification of the joint structure between the leaf spring 7 and the armature 10 in the dot print head according to the present invention. In the modification shown in FIG. 4, at the step 21 formed by the cutout formed on the lower surface of the armature 10, the surface on which the leaf spring 7 is in close contact has an angle so that the leaf spring 7 and the armature 10
The armature 10 is formed so as to be fixed at an angle θ with respect to the leaf spring 7 in a state in which the armature 10 is in close contact. Therefore, in the case of this modification, in a state where the armature rotation center 18 of the leaf spring 7 is in contact with the rotation fulcrum 6b,
Since the armature 10 is arranged at an angle θ with respect to the upper surface of the rotation fulcrum 6b, the upper surface of the core 14, the upper surface of the rotation fulcrum 6b at the second yoke, and the second armature 10 as in the above embodiment. There is no need to provide a step between the projection 6a and the surface.

[0029]

As described above, according to the wire dot print head of the present invention, the joint portion between the free end of the flexible portion and the armature is set closer to the main body than the position directly above the core. Since a structure is realized in which a part of the spring does not wrap around the magnetic path portion and the driving portion of the attracted magnetic flux, that is, just above the core, a thick and strong plate without a decrease in the attractive force or an increase in the inertial mass is caused. A leaf spring can be employed. This makes it possible to speed up the printing operation by using the strong spring force of the leaf spring, thereby enabling high-speed printing.
Also, a step equivalent to the thickness of the leaf spring is provided on the lower surface of the armature, and the free end of the flexible portion is fixed to the portion of the step by closely contacting the free end, so that the leaf spring and the armature are on the lower surface of the armature. Since the armature is in one state, the armature can be attracted to the core and the bending energy can be stored in the flexible portion of the leaf spring without separately adjusting the height of the other components. Further, according to the present invention, in the notch formed on the lower surface of the armature, the surface where the leaf spring is in close contact is formed at an angle, and the armature is in a state where the leaf spring and the armature are in close contact with each other. Since the armature is fixed at a predetermined angle with respect to the spring, the bending energy is stored in the leaf spring while the armature is attracted to the core. There is no need to provide a step between the plate spring and the fixed portion supporting the main body.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a wire dot print head shown as one embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a main part of the embodiment.

FIG. 3 is an enlarged plan view of a main part of the embodiment.

FIG. 4 is a side view showing a modification of the embodiment.

FIG. 5 is a schematic sectional view showing an example of a conventional print head.

FIG. 6 is an enlarged top view of a main part of the print head shown in FIG.

[Explanation of symbols]

 Reference Signs List 5 permanent magnet 6 second yoke 6b rotation fulcrum 7 leaf spring 7a main body 10 armature 11 print wire 13 coil 14 core 18 armature rotation center 21 step 27b flexible part

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kiyoshi Ikeda 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A-57-22073 (JP, A) JP-A-59-38068 (JP, A) JP-A-2-212155 (JP, A) JP-A-60-154084 (JP, A)

Claims (2)

(57) [Scope of request for utility model registration] 1. A base end side of an armature having a print wire attached to a distal end thereof is fixed to a free end side of a flexible portion protruding toward a center from a main body portion to which a leaf spring is fixed, and said main body portion is fixed. The armature is magnetically attracted to the core side together with the flexible portion with the pivotal fulcrum provided between the core and the core as a fulcrum, and the flexible portion is rotated and held in a state where the flexible portion stores the bending energy, thereby performing a printing operation. Sometimes, the magnetic attraction is released, and the accumulated bending energy of the flexible portion is released, so that the print wire performs an impact operation, wherein a joint between the free end of the flexible portion and the armature is formed. At the same time, it is set closer to the main body than the position directly above the core, and a step corresponding to the thickness of the leaf spring is formed on the lower surface of the armature by cutting the lower surface from the base end. Only, a wire dot printing head, characterized by comprising fixing a free end of the flexible portion in close contact by abutting on the step. 2. The dot printing according to claim 1, wherein the armature is provided at a predetermined angle with respect to the flexible portion in a direction in which a tip end side of the armature is separated from a surface of the core. head.