JPS58163668A - Impact printer head - Google Patents

Abstract

PURPOSE:To provide a piezo-electric impact printer head which enables reducing of the size of a piezo-electric body, and besides, is hard to break, by a method wherein a head is structured such that a high tensile force is prevented from being exerted on the piezo-electric body, and the longitudinal effect of the piezo- electric body is utilized. CONSTITUTION:One end of a longitudinal effect piezo-electric body 10, including an electrostriction material, is bound to a fixed member 13 through the medium of a binding member 11, and the other end is bound to one end of a first arm 14 through the medium of a binding member 12. When the piezoelectric body 10 stretches upward as a result of the application of a voltage, the arm 14 displaces in a direction of an arrow mark with a binding member 15 serving as a fulcrum. This causes an enlarged displacement to be also produced on a second arm 18, linked to the first arm 14 through the medium of a binding member 16, in a direction of an arrow mark by the principle of the lever. The second arm 18, having a shock member 19 attached to the tip thereof, is struck on a platen. Additionally a stopper 20, serving to limit the displacement of the second arm 18 to a given distance, is installed.

Description

[Detailed description of the invention] The present invention relates to an impact printer head.

Especially head KIN using piezoelectric or electrostrictive ceramic.
do.

Conventionally, this type of printer head has an electrostrictive vibrator L with one end fixed and a piezoelectric transverse effect or an electrostrictive ceramic affixed to the side surface of nine bullets, as shown in Figure 1 (aJK); It consists of a bottle 2 attached to the tip of the electrostrictive vibrator 1, and the tip is moved toward the left in the figure by lateral expansion and contraction caused by applying, for example, +200 VO voltage in the thickness direction of the electrostrictive vibrator 1. By displacing the ribbon to Bi/2.

It has a structure in which printing is performed by impacting the platen 7 through the paper.

However, in order for the bin 2 to obtain a predetermined displacement and speed, a bias voltage of opposite polarity must be applied in advance to the platen 7.
After displacing the tip of the electrostrictive vibrator l in the opposite direction to the position t indicated by α in the figure, a voltage opposite to the bias voltage is applied and the position indicated by β in the figure is displaced by the trench, thereby creating a via. It is necessary to collide with the 2t platen 7. FIG. 2B shows a case in which the above-described printer head is housed in a suitable case, and a plurality of heads are gathered together so that predetermined printing can be performed using a plurality of pins 2.

The above-mentioned conventional printer head requires low driving power and has a simple structure, but has the drawbacks of slow printing speed and the required volume of piezoelectric t* and electrostrictive ramic. The piezoelectric ceramic referred to here is a piezoelectric material represented by zircon and lead titanate6? , electrostrictive ceramics are electrostrictive materials such as lead niobate in manganese. The difference between piezoelectric and electrostrictive materials is that the former produces polarization, whereas the latter does not produce polarization. Further, the transverse effect means a strain effect in a direction perpendicular to the direction of an electric field applied to a piezoelectric material (including piezoelectric materials and electrostrictive materials).

Piezoelectric materials have transverse and longitudinal effects, and the magnitude of the strain is approximately the ratio of Poisson's ratio when comparing the same materials, that is, approximately 1 = 3. If you compare it to the square of the strain, that is, the ratio is 120. Therefore, in the conventional printer head that uses the transverse effect as mentioned above, the required volume of the piezoelectric body is large.
Therefore, in order to solve this drawback, it is possible to use the longitudinal effect, but this is not easy because the mechanical force applied to the piezoelectric body becomes excessive and the piezoelectric body is destroyed. If a mechanism that expands using a lever or the like is provided in multiple stages, displacement of the arm or the like will generate an excessive tensile force on the piezoelectric body, which may lead to breakage.

The purpose of the present invention is to solve the above-mentioned conventional drawbacks and to
It is an object of the present invention to provide a printer head that reduces the volume of a piezoelectric material by utilizing the longitudinal effect of the piezoelectric material (including the piezoelectric material and the electrostrictive material tube), and that does not have the risk of being destroyed.

The printer head of the present invention includes a longitudinal effect piezoelectric material whose one end is coupled to a fixing member, and two coupling parts close to the end, one of which is coupled to the fixing member and the other of which is coupled to the fixing member. A first arm coupled to the other end of the longitudinal effect piezoelectric body, and two coupling portions in close proximity to each other, the l@ of which is coupled to the other end of the first arm, and the other 1llt! a second member coupled to the fixing member;
The present invention is characterized by comprising an arm, an impact member or a wire fixed to the other end of the second arm, and a stopper fixed to the fixed member for limiting the amplitude of the movement of the 112 arms.

In addition, in the above printer head, the piezoelectric material or the electrostrictive material is formed into a plate shape, and positive and
If negative electrode gold is alternately sandwiched and stacked to form a single body, it is possible to operate at a relatively low voltage. In this case, when piezoelectric materials are used, each piezoelectric material must be polarized in advance in the direction of the electric field applied to each electrode plate. Further, when the impact member is made of wire, it is convenient to provide a hole in the stopper through which the wire is inserted, since a chain hole can be used to guide the wire.

Next, one embodiment of the present invention will be explained in detail with reference to one drawing.

This study shows that, like concrete, the allowable strength of piezoelectric materials is very different between compressive force and tensile force. The tensile force is usually about 300 kp/csz1, and even with materials that are strong against 41, the tensile force is only about 500 to 700, and the piezoelectric material is structured so that no large tensile force is applied.

Next, the principle of the present invention will be explained with reference to Fig. 2 and Fig. 3. In Figure 2, longitudinal effect piezoelectric materials (including piezoelectric and electrostrictive materials) l.

One end is a longitudinal effect piezoelectric material which is connected to the fixing member 13 through a coupling 11 and extends upward in the figure by applying an electric field. One end of the first arm 14 has two adjacent coupling members 12 and 15t, which are coupled to the other end of the piezoelectric body 10 by the coupling member 12 and connected to the fixed member 13 by the coupling member 15. be combined. Therefore, when the piezoelectric body 10 extends upward in the drawing, the first arm 14 receives a force that rotates the coupling member 15 in a counterclockwise direction using the coupling member 15 as a fulcrum. That is, the first arm 14
The end portion is displaced in the direction of the arrow. Connecting member 12゜1sFi
Since they are close to each other, a slight elongation of the piezoelectric body 10 causes the first
The other end of the arm 14 can be largely displaced. The second arm 18 is formed in an L-shape, the longer arm piece is positioned almost horizontally in FIG. The end is connected to the upper end of the second arm by a connecting member 16. Therefore, in the second arm 18,
When the upper end of the first arm 14 is displaced to the left, it receives a rotational force clockwise about the coupling member 17 as a fulcrum;
The tip of the longer arm is displaced upward in the figure. Above 2
Since the coupling members 16 and 17a are relatively close to each other (with respect to the entire length of the arm), the leftward displacement of the lower end of the 11120 arm 18 is magnified and transmitted to the tip of the longer arm. An impact member 19 is fixed to the tip of the longer arm of the rattan 2. Therefore, piezoelectric body 1
The extension of G is magnified in two steps and transmitted to the impact member 19, and the platen can be impacted by displacement of the impact member 19 in the direction indicated by the arrow. The first arm 14 and the arm 18 of II2 may be of any structure as long as the displacement applied to one end is magnified and transmitted to the other end; for example, they may be rod-shaped levers. However, the above-described structure is advantageous in that it can be formed compactly.

The above structure and two-stage expansion have the effect that the piezoelectric body 1G only needs to be slightly elongated. On the other hand, although a large compressive force is applied to the piezoelectric body 10, there is no problem because the strength of the piezoelectric body 1G against the compressive force is sufficiently large. However, if the tip of the arm 18 of the string 2 moves significantly due to inertia or the like, a tensile force will be applied to the piezoelectric body 10. Therefore, the movement of the tip of the second arm 18 is restricted by the stopper 20. Stopper 20Fi fixing member 1
It is fixed to 3.

FIG. 3(a) is a diagram showing a transient phenomenon of the movement of the impact member 19 in the direction of the arrow. That is, when an applied voltage as shown in FIG. 2C is applied to the piezoelectric body 1o, the displacement of the impact member 19 is limited to the amplitude A by the stopper 2o, and then returns to the original state. If there is no stopper 2o, the displacement will occur with the amplitude Alt, as shown by the dotted line in the figure. The same figure (b
) indicates the time course of the force applied to the piezoelectric body 10,
Positive means compressive force and negative means tensile force. The dotted line is stopper 2o
Shows the power when there is no. That is, when there is no stopper 2o, the maximum tensile force F, is equal to the maximum compressive force F, but due to the presence of the stopper 2o, the maximum tensile force F,
can be suppressed to The maximum tensile force F, is a fraction of F. For example, when the impact energy of an impact member is 6000 ergs, F is 2゜kg and It
m is 5ky. Now, the cross-sectional dimensions of the piezoelectric body are 2 x 3
Assuming that, the strength of a normal piezoelectric material (5,300 kg and 7 cm can withstand a tensile force of 18 kl, so the above ?) would destroy it, but the strength of i' is at a level where there is no problem even if it is applied 9 times repeatedly. It is in.

Generally, when an impact printer head is installed in a printer, under normal conditions, the impact member 19 will hit the paper even if the stopper O is not present! ! It has the same effect as the stopper 20, so there is no problem. However, when operating only with the head, or during adjustment work where the distance between the head and the platen is adjusted to set an appropriate printing pressure, the second arm may be in a free state II or close to it. Therefore, the practical effect of the stopper 2o is great. In addition, this allows the application of excessive tensile force to the piezoelectric body to be cut off, making it possible to reduce the volume of the piezoelectric body by utilizing the vertical effect of the piezoelectric body ◇Also, II
Since the configuration is such that the displacement is expanded in two stages by arms I and 2, large &I
i can get the speed of attack.

FIG. 4 is a perspective view showing an embodiment of the present invention. That is, the coupling members 11, 12 are formed to have a T-shaped cross section, and their flat surfaces are firmly fixed to the piezoelectric body 10 by adhesive, soldering, or the like. The bending force applied to the connecting member is absorbed by the bending of the legs of the connecting member. There is a t-spinning effect that reduces the strength of the bonded portion of the piezoelectric body IO. Further, the coupling members 15, 16, 17, etc. are formed of plate-shaped elastic bodies and can absorb bending force. The impact member 19 is made of wire. External terminal 21.22#i piezoelectric body 1
This is a terminal that applies voltage to 0. In other parts, the same configuration is indicated by the same reference numerals as in the principle diagram shown in FIG. 2. Of course, it is jin that has the aforementioned effect.

FIG. 5(a) shows the external terminals 21° and 22 in this embodiment.
A side view showing lil with no voltage applied between them, the same figure (
b) is a side view showing a state where a voltage is applied. All reference numerals in these figures are the same as those described in FIG. In the same figure (b).

The piezoelectric body 10 generates an elongation strain, pushes up the 11Al arm 14, excites rotation in the θ direction, and rotates the second arm 1B.
, the second arm 18 is excited to rotate in the direction θ and comes into contact with the stopper 20.
When the second arm 18 does not move, the second arm 18 goes too far through the rotation angle corresponding to the elongation of the piezoelectric body 10 and generates a strong tensile force on the piezoelectric body, but this is prevented by the strut horn (20). , O indicating an example of the configuration of the piezoelectric body 10, that is, 1
For example, a piezoelectric material such as zircon or lead titanate is laminated by sandwiching the negative electrode plate 31 and the positive electrode @32 alternately between the plate-shaped piezoelectric material 10a formed into a shape, and the negative electrode plate 31 is all external. The positive electrode plate 32 is connected to the external electrode 33.

External electrodes 33.34 connect to external terminals 21.22.

Each plate-shaped piezoelectric material 10M is polarized in the direction indicated by an arrow 3s in the figure. This polarization direction is reversed layer by layer. A positive voltage is applied to the external terminal 21 of the piezoelectric body configured as described above.

When a negative voltage is applied to external terminal 22, an electric field is generated in the direction indicated by arrow 36. Since the direction of the electric field coincides with the polarization direction, when the piezoelectric body extends in the vertical direction in the figure, the distance between the electrode plates 10a, that is, the thickness of the plate-shaped piezoelectric material 10 m, can be made small. It is possible to generate sufficient strain with a low applied voltage.

FIG. 7 shows an example of a piezoelectric body using an electrostrictive material of manganese/lead niobate. The mechanical structure in this case is similar to that shown in FIG. 6, and like reference numerals indicate like structural members. However, the electrostrictive material t11! There is no polarization because it is used. In this case, it extends in the vertical direction in the figure, regardless of the polarity of the voltage applied to the external terminals 21 and 22. Note that electrostrictive materials are characterized by the absence of hysteresis. As described above, distortion can be generated with a low applied voltage.

FIG. 8 is a perspective view showing another embodiment of the present invention, in which a plurality of heads shown in FIG. 4 are assembled and housed in a case 41, and the bottom surface of each fixing member 13 is fixed to the case 41. . In the upper central part of the case 410 in the figure, holes through which the tips of a plurality of wires (impact members) 19 are inserted, ie, wire guides 40, are arranged to improve the positional accuracy of each wire hitting the platen. The stopper 20 is arranged with holes for guiding the intermediate IIt of each wire and is fixed to the case 41. FIG. 9 is a side view showing a part of the stopper 20. and the bottom of arm 1
There is a distance of a clearance 50 between the upper surface of the distal end portion of No. 8 and the upper surface of the distal end portion of No. This clearance 50 limits the amplitude of the second arm 18. Since the zero stopper 20 also serves as a wire guide, the number of parts can be reduced, and the second arm 18
This has the effect of reducing the impact that is transmitted to the piezoelectric body 10 when it hits the stopper.

As described above, since the present invention has a structure that utilizes the longitudinal effect of the piezoelectric body, there is an advantage that the required volume of the piezoelectric body may be small. Further, since the structure is such that the displacement is expanded in two stages by the first arm and the arm 1I2, the impact member can be driven with the required amplitude and speed by a slight extension of the piezoelectric body. There is no need to apply a reverse bias to accelerate as in the past. Furthermore, the stopper allows the thread 2
Since the structure limits the amplitude of the arms, it has the effect of not applying excessive tensile force to the piezoelectric body. Furthermore, if piezoelectric bodies are laminated in multiple layers and electrodes are placed between each layer, it is possible to drive with a low voltage. Further, the structure is simple and it is easy to form a shape suitable for assembling a plurality of wires, and the required number of female wires can be easily arranged in parallel. It has many effects and advantages such as the stopper can also be used as a wire guide and the number of parts can be reduced.

[Brief explanation of the drawing]

FIG. 1(a) is a side view showing an example of a tube of a conventional impact printer head, and FIG. 1(b) is a perspective view showing an assembly thereof.
Fig. 2 is a configuration diagram for explaining the present invention in detail, Fig. 3 is a diagram for explaining the effect of the stopper, Fig. 4 is a perspective view showing an embodiment of the present invention, and Fig. 5 (a ) is a side view showing the state St of the above embodiment when no voltage is applied;
The figure is a perspective view showing an example of a piezoelectric body for use in the above embodiment Kf,
Figure 8 is a perspective view showing another embodiment of the present invention, and Figure 9 is a partial side view of the above embodiment. - In the figure, lO...piezoelectric material, 11, 12.15-1
7... Connecting member, 13... Fixing member, 14... First arm, 1B... Strain 2 arm, 19... Impact member, 20... Stopper, 21.22...・External terminal, 31° 32... Electrode plate, 33.34... Electrode, 4
0...Wire guide, 41? ··Case. Agent Patent Attorney 1) Toshi So 1st reason) Figure 2 Figure 3 Figure 4 (a) Figure 5 6 Figure 6 Figure 7 Figure 8 Figure 9

Claims (3)

[Claims] (1) A longitudinal effect piezoelectric body whose one end is coupled to a fixing member. a first arm having two coupling parts adjacent to the end, one of which is coupled to the fixing member and the other of which is coupled to the other end of the longitudinal effect piezoelectric body; It has two connecting parts, one of which is connected to the other end of the first arm, and the other one is connected to the other end of the first arm.
a second arm coupled to the fixing member; an impact member or wire fixed to the other end of the second arm; and a stopper fixed to the fixing member to limit the amplitude of movement of the second arm. Impact printer head with t% mold. (2) In the impact printer head according to claim 1, the longitudinal effect piezoelectric material is formed by laminating positive and negative electrode plates alternately sandwiched between a plurality of plate-shaped piezoelectric materials, and the above-mentioned The plurality of plate-shaped piezoelectric materials must be polarized in the direction of the electric field applied to the electrode plate. (3) Inno (
In the present invention, the longitudinal effect piezoelectric material is formed by laminating a plurality of O@-shaped electrostrictive materials alternately sandwiching positive and negative electrode plates. (A) In the impact printer head according to Claim 1. 12 or 3, the impact member is formed of a hard wire, and the stopper is provided with a hole through which the wire is inserted. % mold.