JPH0722994B2 - Dot printer head assembly method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of assembling a dot printer head in which a print wire is moved to a print position by swinging an armature based on energization of a coil. .

[Prior Art] Conventionally, a dot printer head in which a plurality of armatures are swingably supported by a head main body via leaf springs, and a print wire is moved to a print position based on the swing of each armature. It has been known. In such a dot printer head, a spacer, a leaf spring, and a front yoke are superposed in a predetermined order on a nose member incorporating a guide member and temporarily assembled. In this state,
A plurality of armatures to which print wires are fixed in advance are positioned and arranged on the leaf springs while inserting the print wires into the guide holes of the guide member, and the respective armatures and leaf springs are fixed to each other. After that, the rear yoke is assembled so that the armature and the core face each other, and the nose member, the spacer, the leaf spring, the front yoke, and the rear yoke are integrally assembled by screwing or by a connecting member.

[Problems to be Solved by the Invention] However, in such a conventional assembling method, the leaf spring to which the armature is fixed is distorted due to the swing of the armature, and strain energy is stored. At this time, unless the fixed end portion of the leaf spring is securely sandwiched by the spacer and the front yoke, the leaf spring will not operate stably,
There is a problem that a characteristic defect such as uneven density of print dots may be caused or the print dot position accuracy may be deteriorated.

Therefore, the present invention aims to solve the above problems,
An object of the present invention is to provide a method of assembling a dot printer head that ensures the operation of a leaf spring, reduces characteristic defects, and realizes printing with higher accuracy.

Configuration of the Invention [Means for Solving the Problems] In order to achieve the above object, the present invention takes the following methods to solve the problems. That is, a rear yoke having a large number of cores around which a coil is wound, an armature supported by a flexible portion of a leaf spring so as to approach and separate from the core, and a front yoke having a large number of slits accommodating the armatures in a radial shape. A print wire having one end fixed to the armature and slidably supported by a large number of guide holes of a guide member; and a spacer that clamps the fixed end of the leaf spring in cooperation with the front yoke. In the method of assembling a dot printer head, wherein a magnetic path is formed through the core, the armature, the front yoke, and the rear yoke, the front yoke, the leaf spring, and the spacer are stacked in this order, and the fixed end portion or the vicinity of the fixed end portion of the leaf spring And the three welded members are assembled between the rear yoke and the guide member. A method of assembling the printer head is in it.

[Operation] In the dot printer head assembling method of the above method, the front yoke, the leaf spring, and the spacer are sequentially stacked, and the fixed end portion of the leaf spring or the vicinity of the fixed end portion is welded, and the fixed end portion of the leaf spring is fixed to the front yoke. It is securely clamped by sandwiching it with a spacer. Therefore, the leaf spring to which the armature is fixed is distorted by the swing of the armature, but the fixed end portion is reliably fixed, and the leaf spring operates reliably to reduce the characteristic defects of the dot printer head and Achieve high-precision printing.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

First, the structure of the dot printer head will be described with reference to FIGS. This dot printer head includes a head body 11 made of a magnetic material.
A column-shaped recess 12 is formed in 11. The bottom wall of the recess 12 and the cylindrical outer peripheral wall form a rear yoke 13. A quadrangular flange portion 14 is radially extended on the opening side of the recess 12. A plurality of cores 15 integrally projecting from the head main body 11 at equal intervals are provided in the recess 12, and a coil 17 is wound around the core 15 via a coil hobbin 16. Has been done.

A plate-shaped permanent magnet 18 having substantially the same outer shape as that of the flange portion 14 is superposed on the flange portion 14. The permanent magnet 18 is composed of a pair of split pieces 19 and 20 having a symmetrical shape. The divided pieces 19 and 20 are stacked on the flange 14 in a butted state, and in this state, an opening 21 having the same shape as the inner diameter of the recess 12 is formed.

A front yoke 24 is laminated on the permanent magnet 18 via a spacer 23 made of a magnetic material, and the same number of slits 25 are formed in the front yoke 24 at positions facing the core 15. There is. The outer shapes of the spacer 23 and the front yoke 24 are the same quadrangle as the permanent magnet 18. Further, between the front yoke 24 and the spacer 23, a piece of the wear preventing film 22 is disposed so as to extend over the end surface of each core 15. The film 22 is made of polyamide having heat resistance and abrasion resistance.

As shown in FIG. 4, a leaf spring 26 made of an elastic material, for example, maraging steel, is laminated on the front yoke 24 together with a spacer 28. This leaf spring 26
A plurality of armatures 30 made of a magnetic material, for example, made of a silicon steel plate are fixed to the. Each armature 30
Is housed in the slit 25, and the print wire 32 extending toward the platen 31 is converged at the distal end of the armature 30 in the central portion of the head main body 11 at its proximal end. It is fixed.

A nose member 33 is provided so as to overlap the spacer 28, and the nose member 33 is provided with a flat plate portion 34 that covers each armature 30 and a tubular guide portion 35 that projects forward. The flat plate portion 34 is in contact with the spacer 28, and the guide portion 35 is fixed with a plurality of guide members 37 each having a plurality of guide holes 36. The print wires 32 are movably inserted into the guide holes 36 of the guide member 37, respectively.

Next, the structure of the leaf spring 26 will be described in detail. The leaf spring 26 is provided with a peripheral edge portion 40 on the outer periphery thereof.
A plurality of base portions 41 radially formed from the inner edge of 40 toward the center thereof are formed. From each of the bases 41, a torsion bar 42 serving as the swing center of each armature 30 is extended in a direction orthogonal to the longitudinal direction of the armature 30, and the ends thereof are connected to both sides of a connecting portion 43 provided radially. Has been done. A pair of bending leaf spring portions 44 are further extended from both sides of the connecting portion 43 in the vicinity where the torsion bar 42 is connected, and the tip of the bending leaf spring portion 44 is concentric with the arrangement circle of the cores 15. It is connected to the eggplant connecting ring 45. The connecting portions 43 are provided by the number of the cores 15 corresponding to the positions of the cores 15, and the armature 30 is fixed to each connecting portion 43 by welding at two welding points 46 and 47. Has been done. As described above, the torsion bar 42 and the bent leaf spring portion 44 are formed as the flexibility of the leaf spring 26.
41 and the connecting ring 45 are configured as a fixed end portion of the leaf spring 26.

A communication hole 49 larger than the connecting portion 43 is formed in the spacer 28 at a position corresponding to the connecting portion 43, and the peripheral edge portion 51 is formed by the connecting arm 50 and the connecting ring 45 of the leaf spring 26.
And a connecting ring 52 having a concentric shape. The end portion of the connecting arm 50 on the peripheral edge side is formed to have a width wider than that of the base portion 41 of the leaf spring 26, and suppresses the bending of the base portion 41 due to the torsional movement of the torsion bar 42. The base 41 of the leaf spring 26 is held between the connecting arm 50 and the front yoke 24, and the connecting ring 45 of the leaf spring 26 is held between the connecting ring 52 and the front yoke 24.

On the other hand, the permanent magnet 18, the spacer 23, the film 22, the front yoke 24, the leaf spring 26, the spacer 28 and the north member 33.
Positioning holes 60, 61, 62, 63, two in each
Two positioning pins 67 planted in the rear yoke 13 are fitted to 64, 65, 66 to position each member, and the members are superposed in the above-described predetermined order.

On the front surface of the nose member 33, a connecting member 71 made of a spring member is attached at its central ring-shaped portion 72, and four projecting pieces 73 bent at a substantially right angle are formed on the outer periphery thereof. Radial protrusions are formed at intervals. Each protrusion 73
A pair of elastic pieces 74 that come into contact with the front surface of the flat plate portion 34 of the nose member 33 are integrally bent and formed on both sides of the base end portion of the
A pair of locking pieces 76 that can be engaged with the locking recesses 75 formed on the rear surface of the rear yoke 13 are integrally bent at the tip of each protrusion 73.

Next, the operation of the dot printer head having the above configuration will be described. First, when each coil 17 is not energized, as shown by the chain double-dashed line in FIG. 5, the permanent magnet 18 causes the front yoke 24, the armature 30, and the core to move.
A magnetic path passing through 15 and the rear yoke 13 is formed, whereby each armature 30 swings around the torsion bar 42 and is attracted to the core 15, and each print wire 32 is arranged at the rear rest position. Along with this, each torsion bar 42 is twisted with the base portion 41 as a fixed end portion, strain energy due to this torsion is accumulated, and each bending leaf spring portion 44 is bent with the connecting ring 45 as a fixed end portion. , Strain energy due to this bending is accumulated.

In this state, selectively energize one of the coils 17,
When the core 15 is temporarily excited so as to cancel the magnetic force of the magnetic path, the torsion bar 42, the strain energy of the bending leaf spring portion 44 causes the armature 30 to swing about the torsion bar 42 to the print position, After that, the permanent magnet 18 is returned and oscillated based on the magnetic force of the permanent magnet 18 and is held at the rest position.

Next, the order of assembling the dot printer head in this embodiment will be described.

First, the spacer 28, the leaf spring 26, and the front yoke 24 are sequentially laminated on the nose member 33 in the corresponding state, and are superposed on the flat plate portion 34. At this time, each member is temporarily assembled with the positioning holes 63 to 66 and the positioning pin 67 positioned. Next, the armature 30 to which the printing wire 32 is fixed in advance is inserted into each slit 25 of the front yoke 24 at a predetermined interval, and the printing wire 32 is guided by a guide member.
Insert it into the guide hole 36 of 37. Then, as shown in FIG. 2, in this state, using a jig or the like, the spacer 28, the leaf spring 26, the front yoke 24, the armature 30 and the leaf spring are provided.
Make a close contact with 26 and fix.

Next, in this state, an electron beam is irradiated from the nose member 33 side through the through hole 48 to perform welding. As shown in FIG.
The front yoke 24, the leaf spring 26, and the spacer 28 are welded to the peripheral edge portion 51 of the spacer 28 and the coupling ring 52 by being irradiated with an electron beam at the welding points 77 and 78 at predetermined intervals. One of the welding points 77 is located on the peripheral edge portion 51 of the spacer 28, and is located on a circle having a predetermined diameter on the peripheral edge portion 40 at the base of the base portion 41 at every other base portion 41 of the leaf spring 26. . The other welding point 78 is located on the connecting ring 52 of the spacer 28 and on every other armature 30 on the connecting ring 45 of the leaf spring 26 on the circle of a predetermined diameter at the tip of the front yoke 24. ing. In addition, the leaf spring 26 and each armature 30 are leaf springs.
At the connecting portion 43 of 26, an electron beam is irradiated and welding is performed at the two welding points 46 and 47.

As a result, the circumferential portion 40 of the leaf spring 26 is integrally sandwiched by the circumferential portion 51 of the spacer 28 and the front yoke 24 by welding, and the base portion 41 as the fixed end portion of the leaf spring 26 is It is firmly clamped by the connecting arm 50 and the front yoke 24. The connecting ring 45 as the fixed end of the leaf spring 26 is connected to the connecting ring 52 of the spacer 28 and the front yoke.
24, the front yoke 24, the leaf spring 26, and the spacer 28 are superposed and integrally fixed by welding. The fixation of these three members is not limited to welding by electron beam, but welding by laser beam may be used, or resistance spot welding or the like may be used.

Thus, the front yoke 24, the leaf spring 26, the spacer 28,
The armature 30 and the nose member 33 are temporarily assembled and then removed from the jig. Then, in the temporarily assembled state shown in FIG. 2, the armature 30 and the front yoke 24 are ground so that the end faces thereof are substantially flush with each other. next,
Permanent magnet so that the armature 30 and the core 15 face each other.
Rear yoke 13 with 18, spacer 23 and film 22 bonded
Assemble to the front yoke 24. At the time of assembling these, the positioning pin 67 is inserted into the positioning holes 60 to 66 of each member and used for positioning each member.

Thus, the front yoke is overlaid on the nose member 33.
The rear yoke 13 is further overlapped on the three members in which the 24, the leaf spring 26, and the spacer 28 are overlapped and integrally fixed, and the three members are assembled between the rear yoke 13 and the guide member 36. In this laminated state, the locking pieces 76 of the respective projecting pieces 73 of the connecting member 71 are engaged with the locking recessed portions 75, and the elastic pieces 74 are elastically contacted with the flat plate portion 34, so that the head body 11 The nose member 33 is laminated to the nose member 33, and each member is sandwiched and fixed.

In the embodiment described above, the nose member 33 has a spacer 28,
Welding was performed after stacking the leaf spring 26 and the front yoke 24, but it is also possible to perform welding with only three members without overlapping with the nose member 33. Also, welding is performed at points other than the welding points 46, 47, 77, 78. You may go. For example, as shown in FIGS. 6 and 7, the armature 30 to which the printing wire 32 is attached in advance is inserted into each slit 25 of the front yoke 24. Along with this, the leaf spring 26 is placed on the front yoke 24, and further, the spacer 28 is placed on the leaf spring 26.
It is temporarily fixed with a jig or the like. The electron beam is emitted from the side of the spacer 28, and the front yoke 24, the leaf spring 26, and the spacer 28 are welded at predetermined welding points 79, 78 and are integrally fixed. One weld 79 is the spacer 28
On the wide portion of the connecting arm 50 on the side of the circumferential portion 51 and on each base 41 of the leaf spring 26 on a circle having a predetermined diameter. The other welding location 80 is located on the connecting ring 52 of the spacer 28 and on the connecting ring 45 of the leaf spring 26 on the circle of a predetermined diameter at the tip of the front yoke 24. Also,
The leaf spring 26 and each armature 30 are irradiated with an electron beam at a connecting portion 43 of the leaf spring 26, so that each of the two welding points 4 is welded.
Welding takes place at 6,47.

As a result, the base portion 41 as the fixed end portion of the leaf spring 26 is firmly and integrally clamped by welding to the connecting arm 50 of the spacer 28 and the front yoke 24. The connecting ring 45 as the fixed end of the leaf spring 26 is integrally clamped by welding at the base of the connecting arm 50 thereof by the connecting ring 52 of the spacer 28 and the front yoke 24, and the front yoke.
24, the leaf spring 26, and the spacer 28 are overlapped and integrally fixed.

Next, as shown in FIG. 7, the front yoke 24, the leaf spring 26,
With the spacer 28 assembled, the front yoke 24
And, the end face of the armature 30 is ground so that the end faces thereof are substantially flush with each other. Thereafter, the temporarily assembled printing wires 32 are inserted into the guide holes 36 of the guide member 37 of the nose member 33, and the nose member 33 is laminated on the spacer 28. Along with this, the permanent magnet 18, the spacer 23 and the film 22 are arranged so that the armature 30 and the core 15 face each other.
Assemble the rear yoke 13 to which is attached to the front yoke 24. Then, as described above, by the connecting member 71,
The head main body 11 to the nose member 33 are laminated so that each member is sandwiched and fixed.

As described above, according to the method of assembling the dot printer head of this embodiment, the front yoke 24, the leaf spring 26, and the spacer 28 are overlapped and integrally fixed by welding, and are connected to the base portion 41 as a fixed end portion of the leaf spring 26. The ring 45 is sandwiched and fixed by the front yoke 24, the connecting arm 50 of the spacer 28, the connecting ring 52 and the like.

Therefore, the torsion bar 42 and the bent leaf spring portion 44 of the leaf spring 26 to which the armature 30 is fixed are elastically deformed by the swing of the armature 30. However, since the base portion 41 as the fixed end portion of the leaf spring 26 and the connecting ring 45 are securely fixed by the front yoke 24 and the connecting arm 50 of the spacer 28, the connecting ring 52 and the like, the torsion portion as the flexible portion. Only the bar 42 and the bent leaf spring portion 44 are strained, and only these act as springs. Therefore, the base 41 as the fixed end and the connecting ring 45 are not distorted and do not act as a spring, and the leaf spring 26 does not exhibit unstable operation. As a result, the leaf spring 26 operates reliably and swings the print wire 32 with a substantially constant biasing force. It does not cause characteristic defects such as unevenness, and does not reduce the accuracy of print dot position.

Note that the present invention is not limited to such embodiments and can be implemented in various modes.

[Advantages of the Invention] As described in detail above, in the method of assembling the dot printer head of the present invention, the front yoke, the leaf spring, and the spacer are sequentially stacked, and the fixed end of the leaf spring or the vicinity of the fixed end is welded to be integrated. Since it is assembled between the rear yoke and the guide member after being fixed, the fixed end portion of the leaf spring is reliably sandwiched and fixed by the front yoke and the spacer.
Although the leaf spring is distorted by the swing of the armature, the fixed end is securely fixed, so the leaf spring operates reliably and reliably, and characteristic defects such as uneven density of print dots are reduced, This brings about an effect of not lowering the positional accuracy.

[Brief description of drawings]

FIG. 1 is a front view of a front yoke, a leaf spring, and a spacer temporarily assembled by using the dot printer head assembling method of the present invention, and FIG. 2 is a nose member, a front yoke, a leaf spring, and a spacer of this embodiment assembled. FIG. 3 is an exploded perspective view of the dot printer head of the present embodiment, FIG. 4 is a cross-sectional view of a main part of the dot printer head of the present embodiment, and FIG. 5 is a dot printer head of the present embodiment. FIG. 6 is a side view with a part broken away, FIG. 6 is a front view of a front yoke, a leaf spring, and a spacer temporarily assembled as another embodiment of the present invention, and FIG. 7 is a front yoke and a board as another embodiment. It is sectional drawing which assembled the spring and the spacer. 13 …… Rear yoke, 24 …… Front yoke 26 …… Leaf springs, 28 …… Spacer 30 …… Armature, 32 …… Printing wire 33 …… Nose member, 36 …… Guide member 37 …… Guide hole

Claims (1)

[Claims] 1. A rear yoke having a large number of cores around which a coil is wound, an armature supported by a flexible portion of a leaf spring so as to approach and separate from the core, and a large number of slits for accommodating the armature in a radial pattern. A front yoke, a print wire having one end fixed to the armature and slidably supported by a plurality of guide holes of a guide member, and a spacer for holding a fixed end portion of the leaf spring in cooperation with the front yoke. In the method of assembling a dot printer, wherein a magnetic path is formed through the core, the armature, the front yoke, and the rear yoke, the front yoke, the leaf spring, and the spacer are sequentially stacked to fix the fixed end portion or the fixed end portion of the leaf spring. Is welded in the vicinity of and the three welded members are assembled between the rear yoke and the guide member. Method of assembling a Topurinta head.