JPH0312523Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a printer head.

[Prior Art] In the case of a printer head in which a printing hammer is driven by an electromagnetic drive device, it is desirable in terms of magnetic efficiency that the center of a movable yoke that holds the printing hammer coincides with the center of a center pole. For this purpose, it is necessary to install the center pole (iron core) vertically without tilting.

If the center pole is fixed vertically to the rear yoke plate by caulking, the center pole can be easily positioned exactly perpendicular to the rear yoke plate, but this does not allow the center pole to move forward or backward. First, it is impossible to adjust the distance between the center pole and the movable yoke.

In order to adjust the distance between the center pole and the movable yoke, the rear end of the center pole is A structure is adopted in which a male thread formed on the rear yoke plate is screwed into a female thread formed on the rear yoke plate.

[Problem to be solved] In order to allow the center pole to move forward and backward while maintaining a vertical state with respect to the rear yoke plate or housing, the rear yoke and housing must be sufficiently If it is thick, or as in Japanese Utility Model Application Publication No. 53-147907, the threaded portion between the seat and the iron core must be made considerably long.

However, this inevitably increases the size of the printer head.

Further, in order to reduce loss due to eddy current of magnetoresistive force, it is preferable that the rear yoke plate has a laminated structure of thin plates. However, even if an attempt is made to cut a female thread into a thin laminate, a drop in processing accuracy cannot be avoided, and for this reason, in a structure in which the male thread of the center pole is screwed into the female thread, a clearance is likely to occur between the threaded parts. However, it was difficult to accurately raise the center pole perpendicularly to the rear yoke plate.

Therefore, the purpose of this invention is to enable the center pole to move forward and backward, to maintain the verticality of the center pole accurately without increasing the size of the head, and to achieve drive efficiency with less loss due to eddy current in the yoke plate. Our goal is to provide superior printer heads.

[Means for Solving the Problems] The feature of the present invention is that the rear yoke plate is composed of laminated thin plates, and the rear yoke plate has a center pole positioning part to ensure the verticality of the center pole. A positioning hole is made in which the outer circumferential surface fits closely, and then an auxiliary plate with a female thread is provided behind the yoke plate, and the male thread of the center pole is screwed into the female thread of this auxiliary plate. While the pole is movable forward and backward, the positioning portion of the center pole is brought into close contact with the positioning hole of the rear yoke plate, so that the center pole is accurately erected relative to the rear yoke plate.

[Embodiment] The details of the present invention will be explained with reference to a preferred embodiment shown in the accompanying drawings.

The front yoke plate 1 is made by laminating three thin plates, and the rear yoke plate 2 is also made by laminating three thin plates like the front yoke plate.
A donut-shaped permanent magnet 3 and a donut-shaped yoke frame 4 are interposed between the two yoke plates 1 and 2. The front ends of three pillars 5, 6, and 7 are fixed to the front yoke plate 1 by caulking or the like as shown in the third figure. This pillar 5,
6 and 7 pass through the donut-shaped permanent magnet 3 and the hollow part 8 of the yoke frame 4, and position them by contacting the inner peripheral surfaces of both.

The rear ends of the columns 5, 6, and 7 pass through the laminated rear yoke plate 2 and an auxiliary plate 9 made of non-magnetic aluminum, and a nut 10 is screwed onto the protruding end and tightened. . The yoke portion is constructed by connecting the front yoke plate 1, permanent magnet 3, yoke frame 4, and rear yoke plate 2, but this connection means is not limited to the above-mentioned support, but may also be performed by adhesive. It's good to wear.

A center pole 12 around which a coil 11 is wound is located within a hollow portion 8 of a yoke frame 4. The center pole 12 has a male threaded portion 12a at its rearmost end.
However, positioning portions 12b are formed in front of the male threaded portions. As shown in the second figure, the male threaded portion 12a passes through the positioning hole 2a of the rear yoke plate 2 and is screwed into the female threaded hole 9a of the auxiliary plate 9, so that the position of the center pole 12 can be adjusted forward and backward.

Furthermore, the positioning hole 2a of the rear yoke plate 2
In order to ensure the verticality of the center pole 12, the positioning part 12b of the center pole 12 is closely fitted, and the inner diameter of the positioning hole 2a has a clearance on the outer circumferential surface of the positioning part 12a of the center pole 12. It fits perfectly. Therefore, even if the thickness of the auxiliary plate 9 is made thinner, the positioning hole 2a of the rear yoke plate 2 prevents the center pole 12 from tilting, and maintains an accurate vertical posture with respect to the rear yoke plate 2. I can do it.

A spring support plate 1 is attached to the front of the front yoke plate 1.
3 to the leaf spring 14 and the stopper plate 1
5 is located, and is positioned by a positioning screw 16 caulked to the front yoke plate 1 and fixed by a spring fixing screw 17.

The printing hammer 18 is fixed to a movable yoke 19, which is attached to the arm 14 of the leaf spring 14.
It is held through the tip of a. Movable yoke 19
The rear end passes through the through hole 1a of the front yoke plate 1, and the rear end face faces the front end face of the center pole 12, and is normally magnetically attracted against the spring force of the leaf spring 14. They are facing each other. A ribbon guide 20 is provided on the front surface of the stopper plate 15. 21 is a terminal plate of the coil.

During printing, by passing current through the coil 11, the magnetic flux attracting the movable yoke 19 is canceled out, and the printing hammer 18 moves forward due to the spring force of the leaf spring 14, printing on recording paper (not shown). .

[Effect] As described above, according to the configuration of the present invention, the rear yoke plate is made of laminated thin plates, and has a positioning hole formed therein to ensure the verticality of the center pole. Since the male threaded part at the rear end of the center pole is screwed into the female threaded part of the auxiliary plate located at Since the perpendicularity of the center pole with respect to the rear yoke plate is ensured by matching, the center of the center pole and the center of the movable yoke (armature) will not deviate from each other, and magnetic efficiency can be increased.

Even if the rear yoke plate has a laminated structure of thin plates in order to reduce loss due to eddy current, the verticality of the center pole can be sufficiently ensured as described above. The verticality of the center pole is ensured by closely fitting the positioning part of the center pole into the positioning hole of the rear yoke plate. This auxiliary plate can be made as thin as possible, so there is no need to provide an unnecessarily long threaded portion as in the conventional case, and the head can therefore be made smaller. It also has the advantage of having a simple configuration and being able to be implemented at low cost.

[Brief explanation of the drawing]

The drawings show an embodiment of the printer head according to the present invention, and FIG. 1 is a partially cutaway front view;
2 is a sectional view taken along the line in FIG. 1, and FIG. 3 is an enlarged sectional view taken along the line shown in FIG. 1...Front yoke plate, 1a...Through hole, 2...
...Rear yoke plate, 2a...Positioning hole, 3...
...Permanent magnet, 4...Yoke frame, 8...Hollow part, 9
...Auxiliary plate, 9a... Female threaded part, 11... Coil, 12... Center pole, 12a... Male threaded part, 12b... Positioning part, 14... Leaf spring, 1
8... Printing hammer, 19... Movable yoke.

Claims (1)

[Claim for Utility Model Registration] A donut-shaped permanent magnet and a yoke frame are interposed and fixed between the front yoke plate and the rear yoke plate, and a center pole is located in the hollow part of the permanent magnet and the yoke frame. The printing hammer is fixed to a movable yoke fixed to the tip of the leaf spring, and the movable yoke passes through a hole in the front yoke plate and faces the front end of the center pole, and is normally attached to the plate. It is magnetically attracted to the center pole against the spring force of the spring, and by energizing the coil wound around the center pole, the magnetic attraction of the movable yoke is released and the printing hammer prints. In the printer head, the center pole has a male threaded portion at its rearmost end and a positioning portion in front of the male threaded portion, and the rear yoke plate is made of laminated thin plates, A positioning hole is formed through which the center pole can be inserted from the rear, and an auxiliary plate having a female thread is arranged behind the rear yoke plate, and the male thread of the center pole is connected to the rear yoke plate. passes through the positioning hole of the center pole and is screwed into the female threaded part of the auxiliary plate, and the positioning part of the center pole tightly fits into the positioning hole of the rear yoke plate, so that the rear yoke A printer head characterized in that the perpendicularity of the center pole with respect to the plate is maintained.