JP2000190491A - Ink-jet printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dramatically reduce the power consumption by including zirconia fibers in piezoelectric ceramics comprising a partition wall with the content ratio of the zirconia fibers on the top plate side of a pressure room smaller than that of the bottom surface side. SOLUTION: Since zirconia fibers 13 with a relative dielectric constant smaller than that of the ceramics and a small reactivity with piezoelectric ceramics are included in piezoelectric ceramics 12 comprising a partition wall 3, even with a partition wall 3 thickness as thin as several tens of μm, the electrostatic capacity can be small. Therefore since the power consumption can be reduced without lowering the displacement amount of the partition wall 3 as well as a large driving voltage needs not be applied, heat generation of the head itself can be restrained, and thus deterioration of the ejection characteristics derived from a heated ink can be prevented. Moreover, since the zirconia fibers 13 are provided with a content ratio on the top plate 5 side of a pressure room 4 smaller than that on the bottom surface side, drastic deterioration of the piezoelectric characteristics of the partition wall 3 can be prevented on the top plate 5 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet printer head used in an ink jet printer for ejecting ink to perform printing.

[0002]

2. Description of the Related Art In recent years, with the development of multimedia,
The use range of printers as information recording devices, particularly ink jet printers, has been rapidly expanding with the spread of personal computers.

As an ink jet printer head (hereinafter referred to as a head) used in an ink jet printer, a plurality of partition walls 23 made of piezoelectric ceramics whose main component is lead zirconate titanate as shown in FIG. A pressure member 22 is formed between the partition walls 23 as a pressure chamber 24, and a top plate 25 is joined on the partition wall 23 and closes each of the pressure chambers 24. An ink ejection hole 27 communicating with each pressurizing chamber 24 is provided on the end side.
And the upper surface of each of the partition walls 23 has an electrode 26 along its longitudinal direction.
And the electrode 2 formed with each partition wall 23 interposed therebetween.
By energizing between the six, the partition wall 23 is bent and displaced by using the shear mode deformation of the piezoelectric ceramics, and the pressure in the pressurizing chamber 24 is changed, so that the ink in the pressurizing chamber 24 is discharged from the ink ejection holes 27. There has been a shear mode type in which discharge is performed (see Japanese Patent Application Laid-Open No. 9-164672, Japanese Patent Application Laid-Open No. 7-101056, and the like). Reference numeral 29 denotes an ink supply hole for guiding ink to the other end of the pressure chamber 24.

In order to manufacture such a head 21, first, in order to form the pressing member 22, a piezoelectric ceramic body mainly composed of lead zirconate titanate or the like is prepared, and cut by a dicing saw. A plurality of pressurizing chambers 24 are formed by machining or blasting.
4 are formed as partition walls 23, and the partition walls 23
After the electrodes 26 are formed along the longitudinal direction of both sides on the upper side, a top plate 25 having an ink supply hole 29 at the top of the partition wall 23 is joined so as to close the pressurizing chamber 24, and the pressurizing chamber 24 is formed. Ink ejection hole 2 so as to close one end of
7 has been formed by joining the nozzle plates 28 having the nozzles 7 (Japanese Patent Laid-Open No. 6-40030, 8-336978).
Reference).

As another method of forming the pressing member 22, a substrate made of ceramics, silicon, or piezoelectric ceramics is prepared, and a lead zirconate titanate forming a partition wall 23 on this substrate is used as a main component. In some cases, a piezoelectric ceramic paste is laminated by screen printing and then fired to form a pressing member 22 in which the substrate and the partition wall 23 are joined and integrated.

[0006]

In recent years, the ink jet printer head 21 has been required to have higher definition and higher density, and the thickness of the partition wall 23 of the pressure member 21 constituting the head 21 and the interval between the partition walls 23 have been demanded. Are required to be reduced to about several tens of micrometers.

However, the partition 23 on which the electrode 26 is formed is formed.
Has a function as a kind of capacitor, so that when the thickness of the partition wall 23 is reduced, the capacitance increases, so that the partition wall 23 can be bent and displaced to a predetermined size without applying a large driving voltage. However, as a result, there is a problem that power consumption increases.

In addition, when a large driving voltage is applied, the heat generation temperature of the head 21 increases, which adversely affects the viscosity of the ink introduced into the pressurizing chamber 24 and causes a variation in the ink ejection speed. In addition, there is a problem that printing and image quality deteriorate. Further, since the piezoelectric ceramics forming the partition walls 23 have not so high mechanical strength, when the pressing member 21 is formed by the above-described cutting or blasting or screen printing,
When the pressure member 22 is handled during the manufacturing process of the head 21, and when the head 21 is driven,
In some cases, breakage, falling off, or chipping of the head 21 may occur, the production yield is low, and the reliability of the head 21 is low.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention has a plurality of partitions made of piezoelectric ceramics arranged in parallel, and a pressing member which serves as a pressure chamber between these partitions, In an ink jet printer head comprising a top plate joined to the top and closing the pressurizing chamber and having electrodes along the longitudinal direction of at least both upper side surfaces of the partition, zirconia fibers are contained in piezoelectric ceramics constituting the partition. It is characterized by containing.

Further, the present invention is characterized in that the occupancy of the zirconia fibers in the piezoelectric ceramic constituting the partition is smaller on the top plate side than on the bottom surface side of the pressurizing chamber.

[0011] Further, the present invention provides that the partition wall has a zirconia fiber occupancy of 30% when viewed in a longitudinal section.
It is characterized by the following.

In the above partition, the top plate side means a portion closer to the top plate than half the height of the partition wall, and the bottom side of the pressurizing chamber means the half of the height of the partition wall of the pressurizing chamber. Refers to the part on the bottom side.

[0013]

According to the present invention, the piezoelectric ceramics forming the partition walls of the pressing member contain zirconia fibers having a lower relative dielectric constant than the above-mentioned piezoelectric ceramics and less reaction with the piezoelectric ceramics. In addition, since the capacitance of the partition walls can be reduced, power consumption can be reduced in a head having a high-density pressurizing chamber, and heat generation of the head can be suppressed. Since the zirconia fibers having higher mechanical strength are dispersed, the mechanical strength of the partition walls can be enhanced, and breakage, shedding, and chipping of the partition walls during the head manufacturing process and during driving can be prevented.

[0014] Further, the partition wall has a lower occupancy rate of the zirconia fiber in the piezoelectric ceramics on the side of the top plate on which the electrodes are formed than the bottom side of the pressurizing chamber, thereby preventing the displacement characteristics of the partition wall from deteriorating. It is possible to prevent a decrease in ink ejection characteristics.

In particular, when the partition walls are viewed in a vertical cross section, by setting the occupancy of the zirconia fibers in the entire partition walls to 30% or less, the capacitance can be reduced while maintaining the displacement amount of the partition walls required for ink ejection. As a result, the consumption electrodes can be greatly reduced, and the accompanying heat generation of the head can be suppressed, so that excellent printing characteristics can be stably provided.

[0016]

Embodiments of the present invention will be described below.

FIG. 1 is a partially broken perspective view showing an example of an ink jet printer head 1 according to the present invention.

The ink jet printer head 1 (hereinafter, referred to as a head) includes a plurality of partition walls 3 arranged in parallel at equal intervals, and a pressing member 2 forming a pressure chamber 4 between the partition walls 3.
And a top plate 5 joined to the partition wall 3 to close each of the pressurizing chambers 4.
A nozzle plate 8 having an ink ejection hole 7 communicating with the partition wall 3 is provided, and electrodes 6 are formed on both side surfaces on the upper side of each of the partition walls 3 along the longitudinal direction thereof. Reference numeral 9 denotes an ink supply hole for guiding ink to the other end of the pressure chamber 4.

The pressing member 2 is formed of a piezoelectric ceramic 12 containing zirconia fibers.
The occupancy of the zirconia fibers in the piezoelectric ceramics forming the partition walls 3 is set to be smaller on the top plate 5 side than on the bottom surface side of the pressure chamber 4.

In order to drive the head 1,
As shown in FIG. 2 (a), an electric current is applied between the electrodes 6 formed on both wall surfaces of the partition wall 3, and the partition wall 3 is bent and displaced so as to expand one pressurizing chamber 4, so that the ink is supplied from the ink supply hole 9. The ink is introduced into the pressurizing chamber 4, and then, as shown in FIG. 2B, when the current is stopped between the electrodes 6 formed on both side surfaces of each partition 3, the partition 3 which has been bent and displaced is turned off. Since the elastic member recovers elasticity and returns to the original state, the inside of the pressurizing chamber 4 can be pressurized and ink can be ejected from the ink ejection hole 7. Thus, printing can be performed on a recording medium (not shown) by repeating these operations.

According to the present invention, FIG.
As shown in (b), the piezoelectric ceramics 12 forming the partition walls 3 contain zirconia fibers 13 having a lower relative dielectric constant than the piezoelectric ceramics and less reaction with the piezoelectric ceramics. Thickness of several tens μ
Even if the thickness is as thin as m, the capacitance can be reduced.
Therefore, the power consumption can be reduced without reducing the displacement amount of the partition 3, and since it is not necessary to apply a large driving voltage, the heat generation of the head 1 itself can be suppressed, and the ink is heated. Therefore, there is no possibility that the discharge characteristics are deteriorated.

Since the zirconia fibers 13 have a higher mechanical strength than the piezoelectric ceramics 12 and have a fibrous shape, they can be dispersed in the piezoelectric ceramics in a tangled state in various directions. 3, the mechanical strength of the head 1
During the manufacturing process and during the operation of the head 1, breakage, shedding, and chipping of the partition walls 3 can be prevented.

However, if the occupation ratio of the zirconia fibers 13 in the piezoelectric ceramics 12 on the side of the top plate 5 on which the electrodes 6 are formed on the partition walls 3 becomes too large, the piezoelectric characteristics of the piezoelectric ceramics 12 are deteriorated. However, in the present invention, since the occupation ratio of the zirconia fibers 13 is smaller on the top plate 5 side than on the bottom surface side of the pressurizing chamber 4, the piezoelectricity on the top plate 5 side of the partition wall 2 is set. There is no significant deterioration in characteristics. As a result, the electrode 6
If a current is supplied during this time, the partition wall 3 can be largely bent and displaced.

In order to achieve such an effect, when the partition walls 3 are viewed in a longitudinal section, the occupancy of the zirconia fibers 13 in the entire partition walls 3 is preferably 30% or less, and more preferably 5 to 10% by weight. Those in the range are good.

That is, if the occupation ratio of the zirconia fibers is more than 30%, the strength of the partition walls 3 becomes too high, so that a large displacement cannot be obtained. This is because chipping and the like easily occur.

Thus, by setting the occupancy of the zirconia fibers 13 to 30% or less, the capacitance can be reduced while maintaining the displacement of the partition wall 3 required for ink ejection, and the power consumption can be reduced. In addition, since the heat generation of the head 1 can be suppressed, excellent printing characteristics can be stably obtained without deteriorating the ink ejection characteristics.

Here, the occupancy of the zirconia fibers 13 refers to the ratio of the area occupied by the zirconia fibers 13 appearing in the cross section to the total area of the partition walls 3 when the partition walls 3 are viewed in a longitudinal section.

By the way, the pressing member 2 having the partition 3
Examples of the piezoelectric ceramics for forming the piezoelectric ceramics include piezoelectric ceramics containing lead zirconate titanate (PZT) as a main component,
Piezoelectric ceramics based on lead magnesium niobate (PMN), piezoelectric ceramics based on lead nickel niobate, piezoelectric ceramics based on lead antimonate stannate, piezoelectric ceramics based on lead titanate It is possible to use piezoelectric ceramics containing barium titanate as a main component, and furthermore, to use piezoelectric ceramics containing a combination of these main components. Preferably, piezoelectric ceramics containing lead magnesium niobate, lead zirconate and lead titanate as main components or It is preferable to use a piezoelectric ceramic mainly composed of lead nickel niobate, lead magnesium niobate, lead zirconate and lead titanate.

The materials of the electrodes 6 formed on both side surfaces of the partition 3 include platinum (Pt), gold (Au), palladium (Pd), rhodium (Rh), nickel (Ni), aluminum (Al) and the like. Metal, Pt-Au, Pb-A
g, an alloy mainly composed of Pt-Pb or the like can be used.

Next, a method of manufacturing the ink jet printer head 1 will be described.

In the method shown in FIG. 3, first, a mold 11 having a recess as shown in FIG. 3A is prepared, and the piezoelectric ceramic particles 14 forming the partition walls 3 are placed in the recess of the mold 11. A mixture 10 composed of zirconia fibers 13 and an organic binder and a dispersant is filled. At this time, since the piezoelectric ceramic particles 14 have a higher specific gravity than the zirconia fibers 13, they gradually begin to settle, and finally the piezoelectric ceramic particles 14 and the zirconia fibers 13 are separated. For this reason, the mixture 10 in the middle of the sedimentation is subjected to reaction hardening or drying and solidification, so that the ratio of the zirconia fibers 13 on the opening side of the concave portion of the molding die 11 is larger than that on the bottom side of the concave portion of the molding die 11. Then, the plate-shaped molded body from which the mold 11 has been released is fired to form a plate-shaped sintered body 15 shown in FIG. 3B.

Next, after polarizing the plate-like sintered body 15 in the direction of the arrow, the surface having the smaller proportion of the zirconia fibers 13 is subjected to a plurality of cutting or blasting with a dicing saw. The grooves are arranged in parallel, the grooves are used as the pressurizing chambers 4, and the pressurizing member 2 shown in FIG.

The pressing member 2 manufactured as described above is
The occupancy of the zirconia fibers 13 in the piezoelectric ceramics forming the partition walls 3 is smaller than that of the top plate 5 than the bottom surface of the pressurizing chamber 4.
Sides can be reduced.

Since the piezoelectric ceramics forming the partition walls 3 contain the zirconia fibers 13,
Breakage, shedding, and chipping of the partition walls 3 during cutting and blasting can be significantly suppressed, and the yield can be increased.

Next, as shown in FIG. 3D, the electrode 6 made of the above-described metal material is formed along the longitudinal direction of both upper wall surfaces of the partition 3 by vapor deposition, sputtering, plating, or the like. Thereafter, a top plate 5 having an ink supply hole 9 made of an insulating material such as ceramics, glass, or silicon is bonded to the top of the partition wall 3 with an adhesive or glass so as to cover the pressurizing chamber 4, and is added. An ink ejection hole 7 made of ceramics, glass, or silicon so as to close one end of the pressure chamber 4.
The ink jet printer head 1 shown in FIG. 1 can be obtained by joining the nozzle plate 8 having the above with an adhesive or glass.

As another method of manufacturing the ink jet printer head 1, as shown in FIG.
A mold 15 having a groove for forming the partition 3 on the bottom surface of the recess is prepared. In the recess of the mold 15, the piezoelectric ceramic particles 14 and the zirconia fiber 13 forming the partition 3, the organic binder, and the dispersion Piezoceramic particles 14 and zirconia fibers 13
After the mixture 10 is reacted and hardened or dried and solidified in the middle of the separation, the mold 16 is released and then fired, whereby the partition walls 3 as shown in FIG. Is formed.

Thereafter, after applying a polarization treatment to the pressing member 2 in the direction of the arrow, electrodes 6 are formed on both wall surfaces of the partition 3 of the pressing member 2 as shown in FIG. Then, by joining the top plate 5 and the nozzle plate 8 respectively, the ink jet printer head 1 shown in FIG. 1 can be obtained.

The method of manufacturing the ink jet printer head 1 of the present invention is not limited to the method shown in FIGS. As long as the piezoelectric ceramics 12 to be formed contain the zirconia fibers 13 and the occupancy of the zirconia fibers 13 is smaller on the upper side than on the lower side of the partition wall 3, any one of the manufacturing methods may be used. .

Furthermore, the ink jet printer head 1 of the present invention is not limited to the one shown in FIG. The one provided on the plate 5 may be used,
The electrodes 6 formed on both wall surfaces of the partition 3 do not deviate from the scope of the present invention such that the electrodes 6 may be provided not only on the upper side of the partition 3 but also on the entire wall surfaces of the partition 3 respectively. What is necessary is just to be formed in the range.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, a pressing member 2 in which a zirconia fiber 13 is contained in a piezoelectric ceramic 12 forming a partition wall 3 is shown.
And the pressing members 22 containing no zirconia fibers 13 in the piezoelectric ceramics 12 forming the partition walls 23, respectively, and confirming the state of breakage of the partition walls 3 and 23 at this time. The electrodes 6 and 26 were formed on both wall surfaces of the partition walls 3 and 23 provided for the partition walls 3 and 23, respectively, and an experiment was conducted to examine the capacitance of the partition walls 3 and 23 and the amount of displacement when the partition walls 3 and 23 were driven.

First, when forming the pressing member 2 containing the zirconia fibers 13 in the piezoelectric ceramics 12 forming the partition walls 3, a forming die 11 having a concave portion made of silicon is prepared. Filling the recesses with a piezoelectric ceramic particle 14 made of lead zirconate titanate, a zirconia fiber 13 having a diameter of about 10 μm and an aspect ratio of about 10, a mixture containing an acrylic binder, and a phosphate ester-based dispersant, After performing vacuum defoaming, it was cured at 100 ° C. in vacuum. At this time, by changing the holding time of the vacuum defoaming, a plate-like molded body in which the sedimentation state of the piezoelectric ceramic particles 14 was changed was produced.

Next, the obtained plate-like molded body is subjected to a binder treatment and then fired at a temperature of 1200 ° C. to produce a plate-like sintered body 15 having a different occupancy of the zirconia fibers 13. did.

Each of the plate-like sintered bodies 15 manufactured as described above had a structure in which the occupancy of the zirconia fibers 13 was gradually increased.

On the other hand, when forming the pressing member 22 containing no zirconia fibers 13 in the piezoelectric ceramics 12 forming the partition walls 23, the piezoelectric ceramics are prepared under the same conditions except that no zirconia fibers are added to the mixture 10. Was obtained.

Then, after a polarization treatment is performed on these plate-like molded bodies 15, a width of 10
The pressure members 2, 22 were formed with grooves at 0 μm, 500 μm in depth, and 200 μm in pitch, and the breakage rate of the partition walls 3 and 23 generated when 10,000 grooves were processed was measured.

As a result, as shown in Table 1, it is understood that the pressure member 2 having the partition walls 3 containing the zirconia fibers 13 in the piezoelectric ceramics 12 can suppress the breakage of the partition walls 3 during cutting. However, even if the partition wall 3 is viewed in a vertical cross section, even if it contains the zirconia fiber 13,
The occupancy of the zirconia fibers 13 in the entire partition 3 is 30
%, The breakage of the partition walls 3 during cutting increased.

Next, along the longitudinal direction of both upper side surfaces of the partition walls 3 and 23 provided on the pressurizing members 2 and 22,
A Au film having a width of μm is coated by sputtering to form an electrode 6,
26, the capacitance of the partition walls 3 and 23 is measured at a frequency of 1 kHz using an impedance analyzer, and the displacement amount when the electrodes 6 and 26 are energized to drive the partition walls 3 and 23 is measured. The measurement was performed using a Doppler vibrometer.

The results are as shown in Table 1.

[0049]

[Table 1]

As a result, the pressing member 22 shown in Sample A, in which the piezoelectric ceramics 12 forming the partition walls 23 do not contain the zirconia fibers 13, suffers large damage of the partition walls 3 during cutting, The capacitance was also the largest at 0.8 nF. As a result, it is understood that when the ink jet printer head 21 is formed using the pressing member 22, the power consumption is large and the heat generation of the head 21 is large.

On the other hand, the zirconia fibers 13 were contained in the piezoelectric ceramics 12 forming the partition walls 3 shown in Samples BG.
, The breakage of the partition wall 3 during cutting can be suppressed and the capacitance of the partition wall 3 can be reduced. As a result, if the ink jet printer head 1 is formed by using the pressing member 2, the reliability of the head 1 can be improved, the production yield can be improved, and the capacitance of the partition wall 3 can be reduced. Therefore, it can be seen that power consumption can be suppressed, and the accompanying heat generation of the head can also be suppressed.

In particular, as shown in Samples BF, when the partition wall 3 is viewed in a longitudinal section, the occupancy of the zirconia fibers 13 is 30%.
% Or less, the breakage of the partition walls 3 during cutting can be significantly suppressed, the production yield of the head can be further improved, and the samples C to
As shown in F, the occupancy of the zirconia fibers 13 was 5 to 3
If it is 0%, the capacitance of the partition 3 can be reduced to 0.7 nF or less, so that it is possible to further reduce the power consumption while maintaining the displacement of the partition required for ink ejection. I understand.

Therefore, when the partition walls 3 are viewed in a longitudinal section, it is understood that the preferable occupation ratio of the zirconia fibers 13 in the piezoelectric ceramics forming the partition walls 3 is 5 to 30%.

[0054]

As described above, according to the present invention, there are provided a plurality of partition walls made of piezoelectric ceramics arranged in parallel,
A pressurizing member serving as a pressurizing chamber between these partitions, and a top plate joined to the top of the partition and closing the pressurizing chamber, comprising electrodes along the longitudinal direction of at least both upper side surfaces of the partition. In the ink jet printer head, the piezoelectric ceramics constituting the partition walls contain zirconia fibers, and the occupancy of the zirconia fibers is made smaller on the top plate side than on the bottom surface side of the pressurizing chamber. In heads with high-density pressure chambers,
Since the capacitance can be reduced while maintaining the displacement of the partition wall required for ink ejection, the number of electrodes consumed can be greatly reduced, and the accompanying heat generation of the head can be suppressed. Can be provided.

Further, since the mechanical strength of the partition walls can be increased, breakage, shedding, and chipping of the partition walls during the head manufacturing process and during driving can be prevented, and the manufacturing yield can be improved. Reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view showing an example of an ink jet printer head according to the present invention.

FIGS. 2A and 2B are cross-sectional views for explaining a driving principle of an ink jet printer head according to the present invention.

FIGS. 3A to 3D are explanatory views showing the steps of manufacturing an ink jet printer head according to the present invention.

FIGS. 4A to 4C are explanatory views showing another manufacturing process of the ink jet printer head according to the present invention.

FIG. 5 is a partially broken perspective view showing an example of a conventional ink jet printer head.

[Explanation of symbols]

1,21: Inkjet printer head 2,22:
Pressing member 3,23: Partition wall 4,24: Pressing chamber 5,25: Top plate
6, 26: Electrode 7, 27: Ink ejection hole 8, 28: Nozzle plate 9, 2
9: Ink supply hole 10: Mixture 11, 15: Mold 12: Piezoelectric ceramic 13: Zirconia fiber 14: Piezoelectric ceramic particle 1
5: Plate-shaped sintered body

Claims (3)

[Claims] A pressure member having a plurality of partitions made of piezoelectric ceramics arranged in parallel and serving as a pressure chamber between the partitions, and a top plate joined to the top of the partition and closing the pressure chamber. An ink-jet printer head comprising: an electrode extending along a longitudinal direction of at least both upper side surfaces of the partition wall, wherein the piezoelectric ceramic constituting the partition wall contains zirconia fiber. 2. The ink jet printer head according to claim 1, wherein the occupation ratio of the zirconia fibers in the piezoelectric ceramic constituting the partition is smaller on the top plate side than on the bottom surface side of the pressurizing chamber. 3. The ink jet printer head according to claim 2, wherein the occupation ratio of the zirconia fibers in the entire partition is 30% or less when the partition is viewed in a longitudinal section.