JPS62292445A - Impact printer head - Google Patents

Abstract

PURPOSE:To obtain a compact printer head minimizing a number of component parts, by providing a plurality of drive units each having a wire fixed on one end of a lever at an end thereof and a means pressing the other end of the lever against a longitudinal effect type piezoelectric element. CONSTITUTION:Where a distance from a projection 11a of a lever 11 to a shaft 12 is l1 and a distance from the shaft 12 to the tip end of the lever 11 is l2, a ratio of lever gamma results in l2/l1. On the side of a wire 15, an impact force is l/1 of that on the side of a piezoelectric element, and an amount of displacement is gamma-times that on the side of the piezoelectric element. By this amount of displacement, the wire 15 moves in a direction of an arrow (g) to press a recording medium for recording. After the completion of recording, the wire 15 moves in the reverse direction up to its original position due to the resiliency from the side of a platen (not shown in the figure). In this manner, the wire can be driven by a displacement enlarging mechanism using a extremely simple lever mechanism, thus a compact head minimizing the number of component parts and having a superior assembly workability can be obtained.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an impact printer head, and more particularly to an impact printer head using piezoelectric or electrostrictive ceramics.

[Prior Art] Conventionally, impact printer heads of this type include those using transverse effect type piezoelectric or electrostrictive ceramics, and those using longitudinal effect type piezoelectrics or electrostrictive ceramics.

The former structure, as shown in FIG. 5, includes an electrostrictive vibrator 1 in which transverse effect type piezoelectric or electrostrictive ceramics la and lb having different polarities are bonded together, and one end attached to the tip of the vibrator l. It consists of a fixed wire 2.

Based on the above structure, first, one electrostrictive ceramic 1
When an electric field is applied in the direction in which a extends, the other electrostrictive ceramic lb contracts and is displaced in the direction of arrow a. Next, when an electric field is applied in the opposite direction, the electrostrictive ceramic la that was stretching earlier
is contracted, and the electrostrictive ceramic lb, which had previously contracted, is expanded and displaced in the direction of the arrow 2, pushing out the recording medium such as an ink ribbon through the wire 2, and recording is performed.

On the other hand, an example of the latter using longitudinal effect type piezoelectric or electrostrictive ceramic is shown in FIG.

In FIG. 6, reference numeral 3 indicates a longitudinal effect pressure 7ti element, which extends in the direction of arrow C when a driving voltage is applied. The elongation of the piezoelectric element 3 generates a rotational moment around the connection part 4a in the support body 4b, which is integrated with the frame 4 through the thin connection part 4a, and causes the support body 4b and the support fixed to its upper end to generate a rotational moment about the connection part 4a. The plate 5 is displaced in the direction shown by arrow d.

The proximal end of a lever 7 is fixed to the distal end of the support plate 5, and the proximal end of the lever 7 and the distal end of the frame 4 are fixed by another support plate 6. Therefore.

The displacement of the support plate 5 in the d direction generates a rotational moment counterclockwise in the figure with the support plate 6 as the center, and the wire 8 is displaced in the direction of the arrow C via the lever 7, thereby performing a recording operation.

[Problems to be Solved by the Invention] By the way, if the 41i structure shown in FIG. 5 is adopted, the print head requires less driving power and has a simple structure, but the printing speed is slow and the print energy obtained is The disadvantage was that it was small.

Furthermore, if the structure shown in Fig. 6 is adopted, the print head uses a longitudinal effect type piezoelectric element, so energy efficiency and response speed are excellent, but the displacement of the piezoelectric element 3 is small (several Since it has a displacement magnification mechanism, it has a complicated structure, requires single-part precision, and is difficult to adjust. Additionally, stress tends to concentrate at the hinge, which poses a problem in terms of durability.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a longitudinal effect type piezoelectric element whose one end is fixed to a support frame, and a longitudinal effect type piezoelectric element whose one end is rotatably supported in the middle and whose one end side is fixed to the supporting frame. A plurality of drive units each having a lever disposed in contact with a piezoelectric element, a wire having one end fixed to the other end of the lever, and means for pressing one end of the lever against the longitudinal effect type piezoelectric element. A unique structure was adopted.

[Function] When the above-described structure is adopted, the vertical effect type piezoelectric element and the lever mechanism can increase the vertical displacement of the piezoelectric element by the ratio of the lever to drive the wire.

[Example] The present invention will be described in detail below based on an example shown in one drawing.

[First Embodiment] FIG. 1 explains the first embodiment of the present invention, and the reference numeral 1O in the figure is a support frame.

One end of a longitudinal effect type piezoelectric element 3 is fixed to its base end.

Further, a wire 15 is fitted into the tip of the horizontally extending @l Oa of the support frame 10 so as to be able to swing freely.

Reference numeral 11 denotes a lever, which is rotatably supported in the middle by a shaft 12 on a fixed part of the device (not shown).

A protrusion 11a is formed at the base end of the lever 11,
It is in contact with the longitudinal effect type piezoelectric element 3.

A saucer 13 is fixed to the tip of the lever 11, and the saucer 13 is in contact with the base end of the wire 15.

A spring 14 is elastically loaded between the base end of the wire 15 and the arm 10a of the support frame, and gives the lever 11 the ability to rotate counterclockwise in FIG.

Based on the above-described structure, when a voltage is applied to the longitudinal effect type piezoelectric element 3, it extends in the direction shown by the arrow f.

The displacement at this time is a minute displacement of about a few liters, but the generated force is about 10 kgf, and this poetic impact force is quite large.

Utilizing this impact force, the lever 11 is rotated clockwise in the figure to cause the wire 15 to protrude against the elastic force of the spring 14 to perform recording.

Now, the distance from the protrusion 11a of the lever 11 to the shaft 12 is ff11. The distance from the shaft 12 to the tip of the lever 11 is 1
2, the lever ratio γ is j! 2/, A'l, and when viewed from the wire 15 side, the impact force is γ/ on the piezoelectric element side.
1, but the amount of displacement is γ times that on the piezoelectric element side.

With this amount of displacement, the wire 15 moves in the direction of arrow g,
The recording medium is pressed to perform recording, and when the pressing is finished, it returns to the opposite direction and returns to the original position due to a repulsive force from the platen side (not shown).

In this way, the wire can be driven by a displacement amplifying mechanism using an extremely simple lever mechanism, and a compact head with a small number of parts and excellent assembly workability can be obtained.

[Second Embodiment] FIG. 2 explains a second embodiment of the present invention. In this embodiment, a protrusion 11a is provided in the middle of the lever 11, and a protrusion 11a is provided in the middle of the lever 11, and A spring 16 is stretched between the frame 10 and the lever 11, giving the lever 11 the ability to rotate counterclockwise in the figure.

At a position beyond the protrusion 11a, the lever 11
2, and a wire 15 is fixed to the tip of the lever 11.

This embodiment is substantially the same as the first embodiment except for the position of the spring 16, and the lever ratio γ=j2
2/121 is also exactly the same as the first embodiment.

Even if the above-described structure is adopted, when a voltage is applied to the longitudinal effect type piezoelectric element 3, it extends in the direction of the arrow f, and the amount of displacement is magnified by γ times, resulting in the displacement of the wire 15 in the direction of the arrow g. The same effects as in the embodiment described above can be obtained.

[Third Embodiment] FIG. 3 explains a third embodiment of the present invention. In the figure, the same parts or corresponding parts as in FIGS. 1 and 2 are given the same reference numerals, and the explanation thereof is is omitted.

In this embodiment, the direction of displacement of the wire 15 is the direction of displacement of the piezoelectric element, and the base end of the lever 11 is connected to the support frame 11 by the shaft 12.
It is rotatably supported via a shaft, and the upper end of the longitudinal effect type piezoelectric element 3 is brought into contact with a protrusion 11a provided in the middle thereof.

A spring 16 is stretched between the vicinity of the tip of the lever 11 and the support frame 10.

Even if the above-mentioned structure is adopted, the displacement of the piezoelectric element can be expanded by lever ratio γ (J22/Jt) times to displace the wire 15 as in the above-mentioned embodiment, and the wire 15 can be displaced in the same way as in the above-mentioned embodiment. Effects can be obtained.

Incidentally, each of the embodiments described above shows a wire drive unit, and in reality, a plurality of these drive units are gathered unevenly to form an impact printer head.

As an example, FIG. 4 shows the structure of an impact printer head using the drive unit shown in FIG. 1.

In the example shown in FIG. 4, the support frame 10 and cover 18 of each drive unit are integrally molded to improve assembly efficiency.

Each wire is collected by a wire guide (not shown) and arranged to have a predetermined character size.

[Effect Zhu] As is clear from the above description, according to the present invention, a wire drive unit can be configured using a longitudinal effect type piezoelectric element and a lever, and without using a complicated displacement amplification mechanism. It is possible to obtain a compact impact printer head that has a small number of parts and is easy to assemble.

[Brief explanation of the drawing]

1 to 3 are perspective views of a drive unit explaining the first to third embodiments of the present invention, FIG. 4 is a partially cutaway perspective view of an impact printer head, and FIGS. 5 and 6 are 5 is a perspective view of a drive unit using a transverse effect type piezoelectric element, and FIG. 6 is a perspective view of a drive unit using a longitudinal effect type piezoelectric element. 3...Longitudinal effect type piezoelectric element lO...Support frame tt...Lever 12...
Shaft 14, 16... Spring 15... Wire track 1 Figure 2 Figure 5 Figure 6 Disconnection

Claims (1)

[Claims] A longitudinal effect piezoelectric element having one end fixed to a support frame, a lever rotatably supported in the middle and disposed with one end in contact with the piezoelectric element, and a wire having one end fixed to the other end of the lever. and means for pressing one end side of the lever against a longitudinal effect type piezoelectric element.