JP2797231B2 - Piezo print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric print head using a piezoelectric actuator.

With the speeding up of impact printer devices,
The electromagnetic method has a limitation in increasing the speed. Accordingly, print heads using piezoelectric actuators have been reviewed. In this case, the amount of displacement due to expansion and contraction of the piezoelectric element is on the order of microns, and this minute displacement is made the amount of displacement that can be printed by the magnifying mechanism. It is necessary to improve the printing quality and extend the service life.

[0003]

2. Description of the Related Art FIG. 10 is a side view of a piezoelectric actuator assembly 1 of a conventional piezoelectric print head. In FIG. 10, 2 is a common base, 3 is a piezoelectric element, 4 is an amateur, and 5 is an enlargement mechanism. A plurality of piezoelectric elements 3 are provided in a predetermined arrangement in the circumferential direction, and the armature 4 and the magnifying mechanism 5
Is provided corresponding to each of them. The piezoelectric element 3 is attached by fixing a base side block 6 provided at a lower portion to the base 2 by bonding or the like. Reference numeral 7 denotes a connector attached to the base 2 and connected to each electrode of the piezoelectric element 3.

[0004] The armature 4 is formed by integrally connecting a beam 9 to a base portion 8, and a printing wire 1 is attached to the tip of the beam 9.
0 is fixed. The enlargement mechanism 5 includes a support spring 11 and a movable spring 12 arranged in parallel. Each spring 1
The upper ends of the support springs 11 and 12 are fixed to the base 8, the lower end of the support spring 11 is fixed to the base 2, and the lower end of the movable spring 12 is fixed to a block 13 separate from the base 2. Reference numeral 14 denotes a horizontal spring for restricting a lateral displacement of an upper portion of the piezoelectric element 3.

The piezoelectric actuator assembly 1 having such a configuration is mounted in a heat sink (not shown) and forms a piezoelectric print head together with a nose mounted on the heat sink and guiding a wire. The piezoelectric printhead is mounted on a carrier and moves with the carrier along a platen. Printing is performed by driving a predetermined piezoelectric element 3 at a predetermined time of this movement, and details thereof are as follows.

At the time of printing, a voltage is applied to the piezoelectric element 3 via the connector 7. As a result, the piezoelectric element 3 is displaced upward and presses the block 13. Then, the enlarging mechanism 5 is operated, and the armature 4 rotates counterclockwise as indicated by the arrow to cause the wire 10 to perform a printing operation. When printing is completed, the voltage application to the piezoelectric element 3 is shut off, and the armature 4 that has completed printing returns to the original position together with the piezoelectric element 3.

[0007]

In the above-described piezoelectric print head having the conventional structure, when driven at a high speed, stress concentrates on the joint between the leaf spring and the amateur in the enlargement mechanism, and the spring is broken. In order to alleviate the stress concentration of each spring, it is necessary to reduce the enlargement ratio or the natural frequency of the enlargement mechanism, but enlargement loss occurs and cannot cope with high-speed printing.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a piezoelectric print head which can prevent stress concentration on each spring of an enlargement mechanism during high-speed driving.

[0009]

According to the present invention, a plurality of piezoelectric elements each having a lower end fixed to a base and a beam having a wire fixed to a tip are integrally connected to a base. A plurality of armatures provided corresponding to the respective piezoelectric elements, a support spring having both ends fixed to the base and the base of the armature, and arranged substantially in parallel with the support spring, and an upper end is provided at the base. Fixed, piezoelectric element at lower end
A piezoelectric actuator comprising a movable spring that is pushed up through a block by displacement of a child, and a magnifying mechanism for enlarging the displacement of the piezoelectric element when voltage is applied and transmitting the displacement to the wire. A configuration (first configuration) is characterized in that only the space between the base and the base is filled with a damping member for vibration suppression and vibration proof.

[0010] In the piezoelectric print head having the first configuration, the buffer member may include a protrusion provided on an upper portion of the base.
A configuration (second configuration) is also characterized in that the space is filled between the bases .

Further, in the piezoelectric print head having the second configuration, the protrusion has an extension extending to above the base.
A configuration (third configuration) is characterized in that a buffer member is also filled between the long portion and the base.

In the present invention, the lower end is fixed to the base.
And a bead with a wire fixed at the tip
Corresponding to each of the above piezoelectric elements
And a plurality of amateurs provided as
A support spring having both ends fixed to a base and the base;
It is arranged almost parallel to the holding spring, and the upper end is fixed to the base.
The lower end is pushed up through the block by the displacement of the piezoelectric element
And a movable spring,
Enlarging mechanism for expanding the displacement of an electric element and transmitting it to the wire
Printing with a piezoelectric actuator assembly having a cavity
In the head, the base and the block, and the base,
Only during this period, a damping member for damping and damping is filled (fourth structure).

Further, in the piezoelectric print head having the fourth structure, the upper surface of the block is flat (fifth structure).

Further, in the piezoelectric print head having the fifth configuration, the buffer member is filled in the buffer member escape prevention yard formed on the upper portion of the block (sixth configuration). I do.

[0015]

When a voltage is applied to the piezoelectric element, elongation deformation (displacement) occurs according to the voltage due to the piezoelectric effect, and the movable spring of the enlargement mechanism is pushed up. As a result, the armature is rotated in the printing direction to apply an enlarged displacement to the wire, and printing is performed by the wire. During this operation, the operation other than that necessary for printing is suppressed by the cushioning member, and breakage of the support spring and the movable spring due to overshoot and undershoot of the amateur assembly is eliminated.

This effect is more remarkable than in the second, third, fourth, fifth and sixth configurations.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIGS. 1 to 4 show a first embodiment.

FIG. 2 is a perspective view showing the appearance of a printer using a piezoelectric print head. In FIG. 2, reference numeral 21 denotes a piezoelectric print head, 22 denotes a platen, and 23 denotes a guide. The piezoelectric print head 21 is mounted on a carrier which is guided by a guide 23 and is movable along a platen 22, and moves along with the carrier to perform printing. The appearance of the piezoelectric print head 21 is shown in FIG.
As shown in FIG. 2, 24 is a nose for guiding the printing operation of the wire, 25 is a heat sink, 26 is a printed board, and 27 is a connector.

FIG. 4 is a side view showing the structure of the piezoelectric print head 21.
5 has a piezoelectric actuator assembly 28 mounted thereon. The structure and operation of the piezoelectric actuator assembly 28 will be described in detail with reference to FIG.

The piezoelectric actuator assembly 28 includes a common annular base 29, a piezoelectric element 30, and an armature 31.
And an enlargement mechanism 32. A plurality of piezoelectric elements 30 are provided in a predetermined arrangement in the circumferential direction.
The enlargement mechanism 32 is provided corresponding to each piezoelectric element 30. The piezoelectric element 30 is attached by fixing a base-side block 33 provided at a lower portion to the base 29 by bonding or the like. 34 is the base 2
The terminal 34a is connected to the connector 27 via the printed board 26.

The armature 31 has a beam 36 on the base 35.
Are integrally connected, and a printing wire 37 is fixed to the tip of the beam 36. The enlargement mechanism 32 includes a support spring 38 and a movable spring 39 which are arranged substantially in parallel. The upper ends of the springs 38 and 39 are fixed to the base 35, the lower end of the support spring 38 is fixed to the base 29, and the lower end of the movable spring 39 is fixed to a block 40 separate from the base 29. Reference numeral 41 denotes a horizontal spring that restricts a lateral displacement of an upper portion of the piezoelectric element 30.

In the piezoelectric print head having such a configuration, the cushioning member 42 is filled between the upper portion of the base 29 and the base 35 in the present invention. Silicone gel or the like is used as the cushioning member 42, and plays a role of damping and damping. In the case of this example, the buffer member 42 has reached the support spring 38. As the silicone gel, ω, α, β, and γ types available from Siegel Co., Ltd. can be used, and the ω type is most suitable.

The printing procedure by the piezoelectric print head 21 is the same as that in the conventional case, and the description is omitted. However, in this embodiment, a damper structure in which a buffer member 42 is filled between the upper portion of the base 29 and the base 35 is employed. In addition, even when driven at a high speed, the overshoot of the amateur 31 is suppressed, and the operation of the wire 37 is stabilized, so that high-quality printing can be performed. Further, breakage of the support spring 38 and the movable spring 39 due to the overshoot of the amateur 31 can be prevented.

FIG. 5 shows a second embodiment.

FIG. 5 is a side view of the piezoelectric actuator assembly of the present embodiment. The piezoelectric actuator assembly 51 has the same configuration as the previous example except that a protrusion 52 is provided on the upper portion of the base 29 and the filling range of the buffer member 42 is excluded. It is similar. The buffer member 42 is filled until it reaches the projection 52. The damper effect in the case of the present example is increased by the amount that the protrusion 52 supports the buffer member 42.

FIG. 6 shows a third embodiment.

FIG. 6 is a side view of the piezoelectric actuator assembly of the present embodiment.
This is the same as the first embodiment except that a bracket (convex portion) 62 is provided on the upper part of the first embodiment and the filling range of the cushioning member 42. The buffer member 42 is also filled between the base portion 35 and the extension portion 62a provided on the bracket 62 and extending above the base portion 35, and the damper effect is improved by this amount.

FIG. 7 shows a fourth embodiment.

FIG. 7 is a side view of the piezoelectric actuator assembly of the present embodiment. The piezoelectric actuator assembly 71 differs from the first embodiment in that the undershoot side is also filled with a buffer member 42. That is, in the case of this example, the support spring 3
8. The buffer member 42 is also filled on the undershoot side between the base 35 and the block 40 so as to surround the movable spring 39. Therefore, the damper effect and the effect of preventing breakage of the spring are further improved.

FIG. 8 shows a fifth embodiment.

FIG. 8 shows a piezoelectric actuator assembly 81 of this embodiment.
FIG. This embodiment is different from the fourth embodiment in that the upper part of the block 40 is flat. This makes it difficult for the buffer member 42 between the base 35 and the block 40 to hang down.

FIG. 9 shows a sixth embodiment.

FIG. 9 shows a piezoelectric actuator assembly 91 of this embodiment.
9 (A) is a side view, and FIG. 9 (B) is a front view. This embodiment is different from the fifth embodiment in that a groove 92 for preventing the buffer member from escaping is provided in the upper part of the block 40. Thereby, the filling of the buffer member 42 is performed more reliably without escaping.

[0035]

As described above, according to the present invention, the printing quality can be improved, and the reliability of the apparatus can be improved by preventing the magnifying mechanism member from being broken during high-speed printing.

[Brief description of the drawings]

FIG. 1 is a side view of a piezoelectric actuator assembly of a piezoelectric print head according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing the appearance of a printer using the piezoelectric print head according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing the appearance of the piezoelectric print head according to the first embodiment of the present invention.

FIG. 4 is a side view showing the structure of the piezoelectric print head according to the first embodiment of the present invention.

FIG. 5 is a side view of a piezoelectric actuator assembly of a piezoelectric print head according to a second embodiment of the present invention.

FIG. 6 is a side view of a piezoelectric actuator assembly of a piezoelectric print head according to a third embodiment of the present invention.

FIG. 7 is a side view of a piezoelectric actuator assembly of a piezoelectric print head according to a fourth embodiment of the present invention.

FIG. 8 is a side view of a piezoelectric actuator assembly of a piezoelectric print head according to a fifth embodiment of the present invention.

FIG. 9 is a structural explanatory view of a piezoelectric actuator assembly of a piezoelectric print head according to a sixth embodiment of the present invention. FIG. 9 (A) is a side view and FIG. 9 (B) is a front view.

FIG. 10 is a side view of a conventional piezoelectric actuator assembly of a piezoelectric print head.

[Explanation of symbols]

Reference Signs List 21 piezoelectric print head 28, 51, 61, 71, 81, 91 piezoelectric actuator assembly 29 base 30 piezoelectric element 31 amateur 32 magnifying mechanism 35 base 36 beam 37 wire 38 support spring 39 movable spring 40 block 42 buffer member 52 convex part 62 Bracket (convex) 62a Extension

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) B41J 2/295

Claims (6)

(57) [Claims] 1. A plurality of piezoelectric elements (30) having a lower end fixed to a base (29) and a beam (36) having a wire (37) fixed at the tip are integrally connected to a base (35). , Each of the piezoelectric elements (3
A plurality of amateurs (31) provided corresponding to (0)
A support spring (38) having both ends fixed to the base (35) of the amateur (31) and the base (29); and a support spring (38) disposed substantially parallel to the support spring (38), and an upper end provided at the base (35). ), The lower end of which is pushed up through the block (40) by the displacement of the piezoelectric element (30).
9), and the piezoelectric element (3
And a magnifying mechanism (32) for enlarging the displacement of (0) and transmitting the displacement to the wire (37), and a piezoelectric actuator head (28) comprising: a base (29) and a base (29). 35. A piezoelectric print head characterized in that a buffer member (42) for damping and damping is filled only during the period (35). 2. The piezoelectric print head according to claim 1, wherein
The cushioning member (42) is provided on the upper part of the base (29).
Filling between the convex part (52) and the base part (35)
A piezoelectric print head characterized by the following. 3. The piezoelectric print head according to claim 2, wherein
The projection has an extension extending above the base (53);
The cushioning member (42) is filled between the long part and the base (35).
A piezoelectric print head characterized in that: 4. A plurality of bases having a lower end fixed to a base (29).
Based on a piezoelectric element (30) and a beam (36) having a wire (37) fixed at the tip.
(35), and each of said piezoelectric elements (3
A plurality of amateurs (31) provided corresponding to (0)
And a base (35) of the amateur (31) and the base
(29) a support spring (38) fixed at both ends to the support;
The spring is disposed substantially parallel to the holding spring (38), and the upper end is formed at the base.
(35) is fixed to the lower end by the displacement of the piezoelectric element (30).
The movable spring (3) which is pushed up through the block (40 )
9), and the piezoelectric element (3
0) to expand the displacement and transmit it to the wire (37).
A piezoelectric actuator assembly (28) having a large mechanism (32).
In the print head, the base (29) and the block (40) and the base
Only between (35) and the damping member (4)
2. A piezoelectric print head filled with 2). 5. The piezoelectric print head according to claim 4, wherein
Te, wherein the top surface of the block (40) is flat
Piezo print head. 6. The piezoelectric print head according to claim 5, wherein the buffer member is filled in a buffer member escape preventing groove formed in an upper portion of the block. Piezo print head.