JPS633967A - Printing head for wire dot printer - Google Patents

Abstract

PURPOSE:To reduce the error of the degree of flatness at both end surfaces of a main yoke and the core and to enhance the accuracy of the gap between a plunger and a core, by constituting the title printing head of the main yoke and an auxiliary yoke and forming the end surface of the main yoke and that of the core on the same plane. CONSTITUTION:A printing head is constituted of a main yoke 5 and an auxiliary yoke 9, and the end surface 5a of the main yoke 5 and the end surface 6a of a core 6 are formed so as to be positioned on the same plane and, therefore, the error of the degree of flatness of each of the end surfaces 5a, 6a can be reduced and the dimensional accuracy of the auxiliary yoke 9 and a plunger 14 is easy to secure and the gap between the plunger 14 and the core 6 can be made highly accurate. Since an armature 13 is arranged so as to be contacted with and opposed to the core, the length of the plunger 14 is shortened to make it possible to achieve wt. reduction and, further, offset force is eliminated because magnetic flux to the plunger 14 passes through the armature 13. By this constitution, high speed response, printing quality, durability and reliability can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a print head for a wire dot printer, and more particularly to an electromagnetic suction type print head.

[Prior Art] Conventionally, as a print head for a suction type wire dot printer, for example, Japanese Patent Application Laid-Open No. 52-62520 (hereinafter referred to as Conventional Example 1) and Japanese Patent Application Laid-Open No. 60-165255 (hereinafter referred to as Conventional Example 2) ), a hollow part of the coil is formed above the suction surface of the core around which the coil is wound, and a plunger fixed to an armature that drives the printing wire is arranged in the hollow part of the coil. Are known.

As described above, since the plunger is disposed within the coil having a high magnetic flux density, the plunger has a feature of high conversion efficiency for converting the electric magnetic force between the coil and the core into mechanical rotation of the armature.

[Problems to be Solved by the Invention] In all of the above conventional examples, the end face of the core is formed lower than the end face of the outer peripheral wall of the cup-shaped yoke. The load error becomes large, and due to the error between the yoke dimensions and the core dimensions, the distance between the plunger and the core (effective gap) cannot be made highly accurate, making it impossible to stably obtain high-speed response and high stamping force. There was a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a print head for a wire dot printer that eliminates the problems of the prior art described above.

[Means for Solving the Problems] The problem with the above-mentioned conventional technology is that the main yoke is formed into a cup shape with an outer peripheral wall, and the ring-shaped auxiliary yoke is attached to the end face of the outer peripheral wall of the main yoke. , a plurality of cores disposed upright inside the main yoke in a substantially ring shape, the tip surfaces of which are flush with the end surface of the outer peripheral wall of the main yoke; a coil pobbin around which a coil is wound beyond the tip surface; a cover formed in a cup shape and attached to the main yoke via the auxiliary yoke; an armature having a plunger that faces the distal end surface of the core inside; and an armature provided on the cover, the outer end of the armature being pressed into contact with the end surface of the outer peripheral wall of the auxiliary yoke, and the armature being supported using the outer end as a fulcrum. This problem can be solved by constructing the armature with a leaf spring that holds the armature so that it can swing back and forth.

[Function] It is composed of a main yoke and an auxiliary yoke, and the end face of the main yoke and the end face of the core are formed on the same plane, so it is possible to reduce the flatness error of both end faces, and the dimensional accuracy of both the auxiliary yoke and the plunger is maintained. Since it is easy to ensure that the gap between the plunger and the core (effective gap) can be made highly accurate.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

A plurality of printing wires 2 (only one is shown in the figure) is slidably provided on the nose 1. The printing wire 2
is biased rearward by a print wire return spring 4 disposed between a print wire bin 3 and a print wire bin 1 fixed to the rear end.

The cup-shaped main yoke 5 has a cylindrical core 6 fixed to the circumference corresponding to the printing wire 2 or integrally formed with a magnetic material by casting, powder molding, etc., and each core 6 has a coil. A coil pobbin 8 having a coil 7 wound thereon is attached. An auxiliary yoke 9 made of a ring-shaped magnetic material is placed on the main yoke 5. Here, the length of the core 6 is short so that the hollow part 8a of the coil pobbin 8 is formed above the suction surface of the core 6, and the end surface 5a of the main yoke 5 and the end surface 6a of the core 6 are on the same plane. It is formed. Further, on the outer periphery of the coil pobbin 8, there is an auxiliary yoke positioning part 8b that protrudes outward, and a cover positioning part 8C that protrudes inward.
is formed.

A flexible printed board 11 is disposed on the opposite side of the main yoke 5 from the core 6 via an insulator 10, and a positioning portion 8d of the solenoid pobbin 8 is inserted into the main yoke 5 and the insulator IO. The flexible printed board 11 is provided with a hole into which the solenoid terminal 8e of the solenoid pobbin 8 is inserted. And positioning of solenoid pobbin 8: f16
8d is inserted into the positioning hole 5b of the main yoke 5 and the coil bobbin positioning hole 10a of the insulator 10,
The solenoid terminal 8e of the solenoid pobbin 8 is inserted into the hole of the flexible printed board 11, and the solenoid terminal 8e
is fixed to the flexible printed board 11 by soldering. As a result, the solenoid pobbin 8, the insulator IO, and the flexible printed board 11 are positioned on the main yoke 5 and assembled together.

At the center of the cup-shaped cover 12, armature tip guide columns 12a are provided corresponding to the plurality of cores 6, respectively, and guide the tip sides of armatures 13 made of magnetic material. Furthermore, armature positioning posts 12b are provided on the outer circumferential side of the cover 12 in correspondence with the armatures 13, and armature positioning holes 13a are provided in the armatures 13 to be inserted into the armature positioning posts 12b. Furthermore, a cover positioning post 12c is provided between the armatures 13 of the cover 12 so as to engage with the cover positioning column 8C of the adjacent solenoid pobbin 8. The armature 13 has a plunger 14 made of a magnetic material inserted into the hollow part 8a of the coil pobbin 8 at a portion corresponding to the core 6.
is fixed, and the armature 13 is biased by an armature plate spring 15 disposed between the cover 12 and the armature 13 so that the negative end contacts the end surface of the auxiliary yoke 9, and the other end contacts the printing wire pin 3. is in contact with. Further, a stopper 16 is provided between the tip side of the armature 13 and the armature leaf spring 15.

Next, assembly will be explained. As described above, the core 6, the solenoid pobbin 8 around which the solenoid 7 is wound, the insulator IO, and the flexible printed board 11 are integrally attached to the main yoke 5.

On the other hand, an armature spring 13 is disposed on the cover 12, and then the inner part of the armature 13 is placed between the armature tip guide posts 12a, and the armature positioning hole 13a of the armature 13 is placed between the armature positioning posts 12a.
Insert it into b.

Therefore, the main yoke 5 is mounted on the nose 1, and the auxiliary yoke 9 is placed on the main yoke 5. As a result, the auxiliary yoke 9 is guided and positioned by the auxiliary yoke positioning portion 8b of the coil pobbin 8. Next, the force t<-12 and the main yoke 5 are combined so that the cover positioning post 12c of the cover 12 is engaged with the cover positioning portion 8c of the solenoid pobbin 8. Finally, the main yoke 5, the auxiliary yoke 9, and the cover 12 are assembled together using fasteners (not shown).

In this way, since it is composed of the main yoke 5 and the auxiliary yoke 9, and the end surface 5a of the main yoke 5 and the end surface 6a of the core 6 are formed on the same plane, the flatness error of the end surfaces 5a and 6a can be reduced. Also, since it is easy to ensure dimensional accuracy for both the auxiliary yoke 9 and the plunger 14, the distance (effective gap) between the plunger 14 and the core 6 can be made highly accurate, and high-speed response and high stamping force can be stably obtained. .

Furthermore, since the armature 13 is disposed in contact with and facing the core 6, the length of the plunger 14 can be shortened and the weight can be reduced. Further, the magnetic circuit is a circuit returning from the core 6, the main yoke 5, the auxiliary yoke 9, the armature 13, and the plunger 14 to the core 6, and since the magnetic flux to the plunger 14 passes through the armature 13, there is no biased force on the plunger 14. As mentioned above, the weight of the plunger 14 is reduced, vibration is reduced, and the unbalanced force on the plunger 14 is eliminated, resulting in stable operation of the armature 13 and a response 1.3 times faster than before with the same energy. It has become possible.

Furthermore, the contact time between the printing paper and the printing wire during printing is shortened, the printing quality is improved, and ribbon catching does not occur. Furthermore, the contact angle of the plunger 14 with respect to the core 6 is also reduced, and the side slip of the plunger 14 is reduced, so that it is excellent in terms of wear and durability and reliability are improved. Additionally, since no yoke is required, problems encountered during yoke processing are also resolved, allowing for high-density mounting.

In addition, in the above embodiment, the type in which the printing wire 2 is pressed by the armature 13 has been explained.
Of course, the present invention can also be applied to a structure in which the printing wire 2 is integrally fixed to the armature 13. Further, the plunger 14 and the armature 13 may be configured as one body.

[Effects of the Invention] As is clear from the above description, the present invention is composed of a main yoke and an auxiliary yoke, and the end face of the main yoke and the end face of the core are formed on the same plane. It is possible to reduce the flatness error of the auxiliary yoke and the plunger, and it is easy to ensure the dimensional accuracy of the auxiliary yoke and plunger, so the distance between the plunger and the core (effective gap) can be made highly accurate, resulting in high speed response, printing quality, durability, and reliability. Improvements can be made.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
It is a sectional view of the main part of the figure. 5: Main yoke, 6: Core, 7: Coil, 8: Coil bobbin, 9: Auxiliary yoke, 12: Cover, 13: Armature,
14 Nibrangia, 15: Armature plate spring. Fig. 1 5: Main yaw 7 6: Fu 7 7: Coil 8: Film ball ° Bottle 9 Nio Yamasuke yofu + 2: Su I hair - 13: Armor dry - L 7 14: Plunger

Claims (1)

[Claims] A main yoke formed into a cup shape with an outer circumferential wall, a ring-shaped auxiliary yoke attached to the end face of the outer circumferential wall of the main yoke, and a ring-shaped auxiliary yoke that stands upright inside the main yoke and is disposed approximately in a ring shape and has a distal end. a plurality of cores whose surfaces are formed to be flush with the end surface of the outer peripheral wall of the main yoke; a coil bobbin which fits into the outer diameter of the cores and has a coil wound thereon beyond the distal end surface of the core; and a coil bobbin formed into a cup shape. a cover that is attached to the main yoke via the auxiliary yoke; an armature that is disposed inside the cover and has a plunger in the center thereof that faces the distal end surface of the core inside the coil bobbin; and the cover. and an armature leaf spring that is provided in the armature and presses the outer end of the armature against an end surface of the outer peripheral wall of the auxiliary yoke and holds the armature so as to be able to swing back and forth using the outer end as a fulcrum. A print head for wire dot printers featuring the following.