JPH0386555A - Printing head - Google Patents

Abstract

PURPOSE:To prevent the variation of tip end positions of printing wires by a method wherein a frame is mounted on a substrate provided with a nose part guiding the printing wire by using a part of the top end surface of the frame as a mounting reference surface. CONSTITUTION:One end of a piezoelectric element 1 in an expanding direction is supported by a base part 3 of a frame 2. A movable element 5 is mounted on the other end of the piezoelectric element. On the top end surface of the frame on the opposite side of the base part 3, a motion conversion mechanism 67 conducting a tilting motion based on the displacement of the movable element 5 is brazed between the frame and the movable element 5. Furthermore, on a substrate 50 provided with a nose part guiding a printing wire 11 driven forward or rearward by the motion conversion mechanism 67, the frame 2 is mounted by using a part of the top end surface thereof as a mounting reference surface. On the top end surface of the frame 2, an antirunning part for a brazing material is provided between a mounting reference surface F abutting against the substrate 50 and the motion conversion mechanism 67.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention displaces a movable element attached to the other end of a piezoelectric element whose one end is supported at the base of a frame in the direction of expansion and contraction of the piezoelectric element. Specifically, the present invention relates to a print head configured to drive a print wire forward and backward through a motion conversion mechanism between the movable element and the frame.

[Prior Art] This type of print head is disclosed in, for example, Patent No. 11 [1163-
There is one disclosed in Japanese Patent No. 312852.

In this case, as shown in FIG. 6, a support 101,
The first. The head main body is mainly composed of second inner substrates 102 and 103, and the second inner substrate 103 is provided with a nose portion 51' for passing the printing wire 11'. Furthermore, the frame 2- of the printing unit PU- is connected to the first substrate 102.
The inner surface of the assembly M is set as the half surface F' and is tightened with a tightening bolt 104. The second board 103 having the nose portion 51- has a fastening piece 105 protruding from its inner surface.
A mounting hole 106 that is long in the direction of expansion and contraction of the piezoelectric element 1- is formed in the tightening piece 105.

Then, a tightening bolt 107 in a direction perpendicular to the direction of expansion and contraction of the piezoelectric element 1' is inserted through the mounting hole 106 of the above-mentioned tightening bolt 105, and the above-mentioned tightening bolt 107 is inserted into the mounting piece 108 protruding from the tip surface of the frame 2'. By tightening the tightening bolts 107, the frame 2'
It is designed so that it can be assembled 6 times.

[Problems to be Solved by the Invention] By the way, in the conventional J3 mentioned above, the inner surface of the first substrate 102 is assembled with the reference surface "'" as the printing unit).
- P U '' frame 2' is assembled, the distance from the reference plane F to the tip of the printing wire 11!J
iL'' is improved, and variations in the tip of the printing wire 11' are likely to occur.
In these two members 2-. If there is a difference in coefficient of thermal expansion between the wires 101, the position of the tip of the printing wire 11 will be displaced back and forth by an amount corresponding to the difference, which will adversely affect printing.

In view of the above-mentioned conventional problems, an object of the present invention is to assemble a frame onto a substrate having a nose portion for guiding a printing wire, using a part of the front end surface of the frame as a reference surface. It is an object of the present invention to provide a print head that can prevent variations in the position of the tip of a wire.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a piezoelectric element having one end in an expansion and contraction direction supported at the base of a frame, a movable member being assembled to the other end of the piezoelectric element, A motion change F! that performs a tilting motion between the frame and the movable element based on the displacement of the movable element on the distal end side of the frame opposite to the base part. A mechanism is brazed, and the motion conversion i
The frame is assembled to a substrate having a nose portion that guides a printing wire that is driven forward and backward by a WJ, with a part of its front end surface used as a reference surface, and a portion of the front end surface of the frame that is in contact with the substrate. The structure is such that a brazing material flow stopper is provided between the contacting assembly GJ reference plane and the motion converting mechanism.

[Function] In the print head configured as described above, the frame is assembled to a substrate having a nose portion using a part of the front end surface of the frame as a reference surface, so that the frame is guided by the nose. The distance between the printing wire tip and the reference plane can be shortened as much as possible, and variations in the printing wire tip position can be reduced. Moreover, even if the frame is expanded or contracted due to temperature changes, the end placement of the printing wire will not be displaced.

Further, when the motion converting mechanism is brazed between the frame's top end surface and the movable element, the brazing material flowing toward the reference surface is stopped at the flow stopping portion of the frame's top end surface when the frame's top end surface is assembled. Therefore, when assembling the frame, it is possible to prevent the brazing material from flowing and adhering to the reference surface.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In FIG. 1, the print head S is mainly composed of a substrate 50 having a nose portion 51 and a predetermined number of printing units PU assembled to the substrate 50.

The substrate 50 is formed into a disk shape, and a recess 50a is formed on the back surface thereof into which a part of the holder 40 for radially supporting each printing unit PU is fitted. Further, the substrate 50 is provided with mounting holes 60 through which tightening bolts 61 for fastening each printing unit PU at the front end surface of the frame 2 are inserted. Further, a cylindrical nose portion 51 is provided protruding from the center of the surface of the substrate 50, and within the nose portion 51, the printing wires 11 of each printing unit PU are connected 7j.
! A predetermined number of guide plates 62 are provided for guiding the vehicle backward.

As shown in FIG. 2, the printing unit PU includes a piezoelectric cord 1, a frame 2, a mover 5, and a motion conversion mechanism 67, and the voltage element 1 is composed of a laminated piezoelectric ceramic that expands and contracts when a voltage is applied. ing. The frame 2 extends substantially parallel to the direction of expansion and contraction of the piezoelectric element 1, and a pair of wedge members 13.
A base 3 for supporting via 14 is provided in a protruding manner.

A movable element 5 is disposed at the other end of the piezoelectric element 1 in the wire drawing direction, facing the tip of the rising portion of the frame 2. A pair of leaf springs 6 and 7 are fixed to opposing surfaces of the movable element 5 and the frame 2 at one end thereof by brazing. Both leaf springs 6.7 face each other with a predetermined gap in between, and extend from the end surfaces of the frame 2 and the movable element 5 by a predetermined length in the direction of expansion and contraction of the piezoelectric element 1. A tilting body 8 is formed integrally with both leaf springs 6, 7 at the other ends (extending ends) thereof.

A motion conversion mechanism 67 is constituted by the leaf springs 6 and 7 and the tilting body 8. Furthermore, a tilting arm 10 made of a flat plate material is fixed to the tilting body 8 at its base, and a printing wire 11 is fixed to the tip of the tilting arm 10 at its base end. The printing wire 11 of each printing unit PU is fitted into the through hole of each guide plate 62 of the nose portion 51 so as to be movable forward and backward.

A subframe 4 is integrally formed at one end of the base 3 of the frame 2. The sub-frame 4 extends along the other side of the piezoelectric element 1 (opposite side to the frame 2) to a position facing the movable element 5.

Between the extending end of the sub-frame 4 and the movable element 5, there is a link forming a four-section parallel link mechanism for guiding the movable element 5 in parallel to the expansion and contraction direction of the piezoelectric element 1 based on the expansion and contraction of the piezoelectric element 1. Plate 16 is assembled.

In each printing unit PU constructed as described above, a part of the front end surface of the frame 2 is used as a reference plane F, and the leaf springs 6, 7, the tilting arm 10, and the printing wire 11 are assembled. Each printing unit PU is assembled with its reference surface F in contact with the back surface of the substrate 50.

On the front end surface of the frame 2, between the reference plane F and the leaf spring 6 of the motion converting mechanism 67, a brazing material for the plate spring 6 is attached toward the reference plane F. A flow stopper 70 is provided to prevent flow. In this embodiment, the flow ll': the part 70
As shown in FIGS. 2 and 3, it protrudes from the tip end surface of the frame 2 at a predetermined height, and the inner wall surface of the flow stopper is used as a flow stopper surface 71 for the brazing material, and the flow stopper 70 The second assembly in which the outer wall surface of the base plate 50 contacts the inner circumferential surface of the four parts 50a of the substrate 50 is set as a reference plane F2.

Further, when assembled to the frame 2, the insertion groove 82 through which the tightening bolt 61 is inserted from the reference plane F and the four portions 83 into which the nut 84 is fitted to prevent rotation of the tightening bolt 61 are in communication. is formed.

Further, in this embodiment, as shown in FIG. 1, a vibration isolating cover 90 made of a vibration isolating material such as rubber or synthetic resin and covering the outer periphery of the print head S is assembled at the peripheral edge of the substrate 50. ing.

This embodiment is constructed as described above. Therefore, when the leaf springs 6 and 7 of the motion conversion mechanism 67 are fixed between the frame 2 and the movable element 5 by brazing, a part of the brazing filler metal is attached to the front end surface of the frame 2, so that the end surface of the frame 2 is attached to the reference surface. When flowing toward F, the flowing brazing filler metal A is stopped at the flow stop surface 71 on the inner surface of the flow stop part 70, as shown in FIG. Therefore, the flowed brazing filler metal A is prevented from adhering to the reference surface F during assembly.

As described above, after both leaf springs 6 and 7 of the motion conversion mechanism 67 are brazed between the frame 2 and the movable element 5, a pair of wedge members 13 and 14 are inserted between the movable element 5 and the frame 2. The piezoelectric element 1 is assembled via the printing unit PtJ to configure the printing unit PtJ.

Then, each printing unit PU is fitted radially into the holding groove of the holder 40 assembled on the back side of the substrate 50, and the printing wire 11 is connected to each guide plate 6 of the nose portion 51.
Insert it into the through hole of 2. After that, each printed conit P t
When assembling the front end surface of the frame 2 of J, the reference surface F is brought into contact with the back surface of the substrate 50, and when assembling the outer wall of the flow stopper 70 on the front end surface of the same frame 2, the second assembly is performed by using the reference surface F2 as the reference surface F of the substrate 50. l!
Insert the tightening bolts 61 from the mounting holes 60 of the substrate 50 as shown in FIGS. Each printing unit PU is assembled to the board 50 by passing it through the push-through groove 82 of the frame 2 of the printing unit PU and tightening it to the nut 84 of the recess 83. At this time, when assembling the front end surface of the frame 2, each printing unit P
LJ is assembled with 1:S accuracy.

Furthermore, the end surface of the frame 2 is used as the reference plane F for assembly.
Due to the structure of assembling it to the substrate 50 having the nose portion 51, the distance from the reference plane F to the tip of the printing wire 11 is 11L.
can be made as short as possible, and variations in the tip position of the printing wire 11 of each printing unit PU can be reduced. Furthermore, even if the frame 2 is expanded or contracted due to temperature changes, the position of the tip of the printing wire 11 will not be displaced.

Further, in the print head S assembled as described above, when a voltage is applied between both electrodes of the piezoelectric element 1 of each printing unit PU, the piezoelectric element 1 moves in the stacking direction, that is, in FIG. It extends by a predetermined length in the direction of arrow X, and the mover 5 is displaced based on this. Then, the leaf spring 7 on the movable element 5 side is pushed up along the leaf spring 6 on the frame 2 side in response to the displacement force of the movable element 5, and both leaf springs 6 and 7 are bent into a groove shape. In particular, the leaf spring 7 on the movable element 5 side is attached to the frame 2.
By largely bending toward the leaf spring 6 on the side, a rotational moment is generated at the base end of the tilting arm 10 in the direction of arrow P, whereby the tilting arm 10 is tilted forward. Then, with the printing wire 11 at the tip of the tilting arm 10 guided by a predetermined number of guide plates 15 of the nose portion 51, the tip is advanced to the printing position.

When the voltage application to the piezoelectric cord 1 is cut off, the piezoelectric element 1 contracts to its original state, and the movable element 5 moves in the opposite direction due to the elastic force based on the deflection of both leaf springs 6 and 7. Displaced. As a result, a rotational moment is generated at the base end of the tilting arm 10 in the opposite direction to that described above, and the tilting arm 10
is moved back 3Jl to the original position d where it abuts the stopper 35 on the tip end surface of the subframe 4.

In the above embodiment, the brazing material flow prevention part 70 was provided protruding from the front end surface of the frame 2 at a predetermined height, but the present invention is not limited to this. For example, as shown in FIG. 5, a brazing material flow stopper 70 may be recessed at a predetermined groove depth between the reference surface and the motion converting mechanism 67 on the front end surface of the frame 2. However, in this case, when the leaf spring 6.7 of the motion converting mechanism 67 is brazed between the frame 2 and the movable element 5, the flowing brazing material is transferred to the flow stopper 70.
The groove should be deep enough to be stopped at the

[Effects of the Invention] As described above, according to the present invention, a part of the front end surface of the frame is used as a reference surface for assembly, and due to the structure in which the frame is attached to a substrate having a nose portion, The distance between the guided print wire tip and the reference plane can be made as short as possible by the assembly, and variations in the print wire tip position can be reduced. Furthermore, even if the frame expands or contracts due to temperature changes, the tip position of the printing wire is not displaced, so printing defects can be prevented.

Further, when the motion converting mechanism is brazed between the frame's top end surface and the movable element, the brazing material flowing toward the reference surface is stopped at the flow stopping portion of the frame's top end surface when the frame's top end surface is assembled. Therefore, when assembling the frame, it is possible to prevent the solder metal from flowing and adhering to the reference surface, and it is possible to save the trouble of removing the adhering brazing material, and it is possible to assemble the frame to the board with high precision. I can do it.

[Brief explanation of drawings]

1 to 4 of the drawings show an embodiment of the present invention, in which FIG. 1 is a side sectional view showing the entire print head, FIG. 2 is a side view showing the printing unit, and FIG. 3 is a side view showing the print head. FIG. 4 is an exploded perspective view showing the assembly of the printing unit with the frame, FIG. It is a side view showing an example. FIG. 6 is a side sectional view showing a conventional print head. 1...Piezoelectric element 2...Frame 3...Base 5...Movable element 6.7...Plate spring 8...Tilt rest 50...Substrate 67...Movement Conversion mechanism 70...Stop flow part F...Assembled on reference surface PU...Printing unit

Claims (1)

[Claims] One end of a piezoelectric element in the expansion and contraction direction is supported at the base of the frame, a movable element is assembled to the other end of the piezoelectric element, and the frame A motion conversion mechanism that performs a tilting motion based on the displacement of the movable element is brazed between the movable element and the movable element, and a substrate having a nose portion that guides a printing wire driven forward and backward by the movement conversion mechanism; The frame is assembled with a part of the front end surface of the frame as an assembly reference surface, and the front end surface of the frame has a portion between the assembly reference surface that comes into contact with the substrate and the movement conversion mechanism by the brazing. A print head characterized by being provided with a brazing material flow stopper.