JPH0698779B2 - Print head - Google Patents

Description

The present invention relates to an armature, a driving means for driving the armature, a printing wire for printing at the ends thereof, and an armature and a printing wire at both ends in the length direction. More particularly, it relates to a print head having a fixed lever.

(Prior Art) In the conventional print head, for example, as described in JP-A-60-48372, the lever is thinned in order to reduce the weight of the armature assembly.
The lever was projected in the lever width direction from the armature fixing portion, and the edge in the lever longitudinal direction on the drive means side with respect to the printing direction was a straight line.

[Problems to be Solved by the Invention]

Conventionally, the print speed of the print head is 60 to 80 for kanji printing.
Characters per second, the armature assembly has an operating frequency of 1440
The thickness of the armature assembly in the printing direction was from Hz to 1920 Hz, and the armature assembly was operable even in the state where both the thickness perpendicular to the lever body operating surface was sufficiently secured and the strength was secured.

However, with the recent increase in printing speed, it is necessary for the armature assembly to operate at 2880 Hz or higher,
Further weight reduction of the armature assembly has been demanded.

To reduce the weight of the armature assembly, it is effective to make the lever thickness thinner, but the prior art does not sufficiently consider the locally excessive stress, and it is difficult to make it thinner than before. It was

That is, in order to secure the strength of the thinned lever, when the lever is projected in the lever width direction from the armature fixing portion, the driving means is attached to the edge of the lever in the printing direction from the print wire fixing point to the armature fixing point. Since the edge on the side is shorter, most of the force applied to the lever is supported by the end of the armature fixing portion on the edge on the drive means side, and the stress on this portion becomes excessive.

An object of the present invention is to reduce the locally excessive stress and improve the reliability, and at the same time, to improve the printing speed by reducing the weight by thinning the lever plate.

[Means for Solving the Problems]

The above-mentioned object is to provide a printing wire, a plate-shaped lever having the printing wire attached to the tip thereof, an armature portion having an inclined surface at a portion for fixing a base end side portion of the lever, and a cross shape elastically supporting the armature. A plurality of armature assemblies each of which is arranged in the circumferential direction, and a plurality of driving means for driving the armature assemblies which are arranged on the side opposite to the wire end with respect to each of the armature assemblies, and the plurality of armature assemblies. A wire guide for guiding each of the wires, the armature assembly, the wire guide,
In a print head configured to have a casing for housing a driving means, wherein the inclined surface is directed toward the center of an armature assembly in which a plurality of the inclined surfaces are arranged from the head end side of the armature toward the driving means, the lever is
A portion inclined toward the print head tip side with respect to the line connecting the non-print side end portion of the tip end to which the print wire is attached and the end surface on the print wire side of the inclined surface of the armature, and this portion integrated And a base end side portion inclined toward the armature side so that the widthwise dimension thereof gradually increases, and the drive means side of the base end side portion of the lever is located closer to the wire side than the wire. This is achieved by fixing the proximal end portion of the lever to the inclined surface portion of the armature.

[Action]

By making the shape of the end face in the longitudinal direction of the lever on the side opposite to the wire striking print side concave, the force acting on the end of the armature fixing part at the edge on the drive means side is dispersed in the direction opposite to the printing direction of the armature fixing part. Thus, it is possible to reduce excessive stress on the fixed portion side. As a result, the reliability of the print head was improved, and the weight of the lever was reduced by thinning the plate, improving the printing speed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a partial cross-sectional view showing the overall structure of a print head embodying the present invention.

In this figure, the leaf spring body 5 extends from a base portion 53 made of an annular plate material toward the center of the base portion so that the plurality of tongues 52 are regularly adjacent to each other. An armature assembly 1 in which a printing wire 2, a lever 3 and an armature 4 are fixed to the tip side of the tongue piece 52 in this order from the tip.
Is fixed.

One of the vertical spring wires 51 is fixed to the vertical spring support plate 10,
The other is fixed to the armature 4. The vertical spring wire 51 intersects with the center line of the tongue piece 52 vertically without contact, and defines the center of rotation of the armature assembly 1 at the intersecting point to prevent the secondary vibration of the tongue piece 52 during the printing operation. The wire 51 receives and prevents it as a tensile compression force in the axial direction.

The core 8 has an insertion portion 82 of the coil 9 corresponding to each armature assembly 1, and the armature assembly 1 is provided on the upper surface thereof.
The core attraction surface 81 for attracting the armature 4 is provided, and each core 8 is fixed to the casing 131 in a state where the permanent magnet 11 and the yoke 14 are laminated on the core outer peripheral portion 83.

The suction surface 81 of the core 8 and the upper surface of the yoke 14 are finished in the same plane. The terminal 93 of the coil 9 is drawn out of the print head from the casing 131. On the upper surface of the yoke 14, a side yoke 7, a spacer 15, a leaf spring body 5, a vertical spring support body 10 and a casing 132, which are formed of a plate material, are laminated, and the coil 9 for driving the armature assembly 1 and the like are fixed. It is fixed to the casing 131 by means such as a screw (not shown).

A wire guide 61 and a wire guide 63 are fixed to the casing 132 so as to restrain the print wire 2 so that the print wire 2 can move back and forth in the axial direction. The wire guide 62 regulates the striking direction with respect to the casing 132, and is in a floating state in a direction perpendicular to the striking direction.

The base portion 53 of the leaf spring body 15 includes the spacer 15 and the vertical spring support body 10.
The tongue piece 52 extends from the base 53 and is a fixed end.

The armature 4 is inserted into a groove (not shown) formed in the circumferential direction of the side yoke 7. A magnetic circuit is formed by the yoke 14, the side yoke 7, and the armature 4, and the attraction force of the permanent magnet 11 causes the armature assembly 1 to move.
Are attracted to the core attraction surface 81 at the armature 4.
At this time, the effective elastic portion 54 is deformed to store strain energy, and a biasing force for returning the armature assembly 1 is generated.

Next, the operation will be described. A current according to the recorded image is passed through each coil 92, the magnetic flux generated by the permanent magnet 11 is canceled by the core attraction surface 81, the magnetic attraction force is reduced, and the biasing force of the leaf spring effective elastic portion 54 is magnetically attracted. The strain energy stored in the leaf spring effective elastic portion 54 is released, and the armature assembly 1 rotates about the intersection of the tongue piece 52 and the vertical spring wire 51, and the printing wire 2 projects from the wire guide 61. Then, a printing medium such as an ink ribbon or printing paper (not shown) is hit to print dots.

Immediately before or immediately after the print wire 2 hits the print medium, the current of the coil 91 is cut off, and the armature assembly 1 returns to the initial position by the reaction force to the print medium and the restored magnetic attraction force.

FIG. 2 is an enlarged perspective view of the main part of the print head of the first embodiment.

The lever 3 drawn with a solid line is the lever of the print head of this embodiment, and is composed of a plate-shaped body. The portion drawn by the one-dot chain line 30 shows the conventional lever shape.

The lever length direction in the figure substantially coincides with the direction toward the print wire fixing portion 21 from the point where the tongue piece 52 and the vertical spring 51 intersect. The width direction substantially coincides with the printing wire longitudinal direction.

The lever 3 has a first end portion 31 and a second end portion 32 at both ends in the lengthwise direction, a fixing portion 21 for the print wire 2 near the first end portion 31, and a second end portion. The end portion 32 is fixed to the armature 4 at the plane portion of the lever, and the fixing portion 42 extends in the length direction and the width direction of the lever, and the second end portion 32 fixes the fixing portion 42.
It projects more in the width direction. The punched hole 33 is a hole provided to reduce the weight of the lever.

Here, the apex 36 on the driving means side of the first end 31 of the lever 3
With respect to the straight line 34 connecting the end portion 37 of the armature fixing portion 41 on the drive means side, the edge 35 on the drive means side of the lever is bent toward the lever center in the vicinity of the second end portion 32. This allows the second
The stress in the vicinity of the end portion 32 was dispersed in the lever width direction, and the stress that was excessive at the end portion 37 in the past could be reduced.

FIG. 3a shows a lever shape of a conventional print head. FIG. 3b shows the lever shape of the print head of the first embodiment. FIG. 3c shows the stress distribution in the AA 'portion of the lever when a force in the longitudinal direction of the print wire is applied to the print head having the shape shown in FIGS. 3a and 3b. In the conventional lever shape, the stress is high near the end portion 37 and the lever plate thickness needs to be 0.2 mm or more.

In the lever shape of the print head of the first embodiment, compared with the conventional shape, the stress near the end portion 37 where the maximum stress occurs, that is, the point A ', is reduced, and it is possible to use a thin plate lever with a plate thickness of 0.15 mm. By reducing the weight of the lever, the operating speed of the armature assembly has been improved.

FIG. 4 shows a second embodiment of the present invention. As shown in the drawing, when the edge 35 on the driving means side of the lever is formed by a plurality of arcs having a finite radius of curvature r, stress is dispersed along the edge 35 in the length direction of the lever. , The stress at the end 37 is further reduced. Furthermore, when the radius of curvature was reduced toward the armature fixing portion 42, the stress at the end portion 37 was further reduced.

Further, when the armature assembly 1 is in operation, the print wire 2 is vibrated and a vibration having an amplitude indicated by δ is generated. This vibration increases the stress on the print wire 2 near the print wire fixing portion 21 and reduces the life of the print wire 2. Here, during the printing operation of the armature assembly 1, the printing wire fixing portion 21
The end 211 in the printing direction of the second end 32 to the first end 3
If you have a motion component M that goes to 1, the printing wire 2
Vibration δ is reduced, the stress of the printing wire 2 is reduced, and the reliability is improved.

〔The invention's effect〕

According to the present invention, by distributing the lever stress of the printhead armature assembly, it is possible to reduce the stress at the joint with the armature that causes excessive stress and improve the reliability of the printhead. Further, the lever can be made thin to reduce the weight of the print head to increase the printing speed.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall structure of a print head embodying the present invention. FIG. 2 is an enlarged perspective view of the main part of the print head according to the first embodiment of the present invention. FIG. 3a shows a lever shape of a conventional print head. FIG. 3b shows the lever shape of the print head according to the first embodiment of the present invention. FIG. 3c shows the lever stress in the portion AA 'when a force is applied to each lever in the longitudinal direction of the printing wire. FIG. 4 is an enlarged perspective view of the main part of the print head according to the second embodiment of the present invention. 1 ... Armature assembly, 2 ... Print wire, 3 ...
Lever, 4 ... Armature, 5 ... Leaf spring body, 8 ...
Core, 9 ... Coil, 11 ... Magnet, 31 ... First end, 32 ... Second end.

Front page continuation (56) References JP-A-59-89174 (JP, A) JP-A-59-155062 (JP, A) Actually opened 61-166844 (JP, U) Actually opened 57-44745 (JP , U) Actual development Sho 61-71449 (JP, U)

Claims (1)

[Claims] 1. A printing wire, a plate-shaped lever having the printing wire attached to a tip thereof, an armature portion having an inclined surface at a portion for fixing a base end side portion of the lever, and a cross for elastically supporting the armature. A plurality of armature assemblies each of which has a spring shape and are arranged in the circumferential direction, and a plurality of driving means for driving the armature assemblies which are arranged on a side opposite to the wire end with respect to each of the armature assemblies, and the plurality of armature assemblies. A wire guide for guiding each wire of the solid body, the armature assembly, the wire guide,
In a print head configured to have a casing for housing a driving means, wherein the inclined surface is directed toward the center of an armature assembly in which a plurality of the inclined surfaces are arranged from the head end side of the armature toward the driving means, the lever is
A portion inclined toward the print head tip side with respect to the line connecting the non-print side end portion of the tip end to which the print wire is attached and the end surface on the print wire side of the inclined surface of the armature, and this portion integrated And a base end side portion inclined toward the armature side so that the widthwise dimension thereof gradually increases, and the drive means side of the base end side portion of the lever is located closer to the wire side than the wire. As described above, the print head is characterized in that the base end side portion of the lever is fixed to the inclined surface portion of the armature.