JP2002127421A - Liquid ejector and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejector and its manufacturing method in which the reliability and durability are enhanced by preventing the characteristics from being deteriorated by liquid (ink). SOLUTION: The liquid ejector comprises an array of a plurality of liquid ejection elements P1 each having a liquid pressurization chamber 112 being filled with liquid (ink) to be ejected, a piezoelectric actuator 111 disposed contiguously thereto and ejecting the liquid by pressurizing the liquid pressurization chamber 112, and a pressure damping chamber 113 disposed oppositely to the liquid pressurization chamber 112 with respect to the piezoelectric actuator 111. A part of the piezoelectric actuator 111 forming the liquid pressurization chamber 112 is composed of a material not corroded by the liquid (e.g. a resin layer 105), so that the piezoelectric actuator 111 does not touch the liquid filling the liquid pressurization chamber 112.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printing apparatus,
The present invention relates to a liquid ejecting apparatus that ejects a printing liquid and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, ink-jet printers have rapidly spread as printers capable of realizing color printing at low cost. What determines the performance of this ink jet printer is an ejection device that ejects ink, and a liquid ejection device that intermittently ejects fine liquid particles.

Here, as a conventional liquid ejecting apparatus, an ink ejecting apparatus for a typical ink jet printer will be described as an example. Ink jet devices for ink jet printers can be broadly classified into two types: a thermal type and a piezoelectric type. In terms of high-speed printing, high-definition printing, and the like, the piezoelectric type is particularly attracting attention.

An example of a typical ink jet device for a piezoelectric type ink jet printer will be described with reference to FIG. FIG. 18 is a cross-sectional view of the ink ejecting element, and shows a cross section of two ink ejecting elements. In FIG. 18, the ink ejection element includes a piezoelectric actuator 801 driven by a piezoelectric action, an ink pressurizing chamber 802, and an ink ejection port 803. The piezoelectric actuator 801 is composed of, for example, a bimorph element composed of two piezoelectric bodies or a unimorph element composed of a piezoelectric body and a diaphragm. Also, in the same figure, the broken lines schematically show the deformation of the piezoelectric actuator 801. In the figure, the x-axis is in the width direction of the piezoelectric actuator 801 (usually, the short side direction), and y is
The axis is in the length direction (usually the long side direction), and the z axis is in the thickness direction. Initially, ink is supplied from an ink storage unit (not shown) provided outside the ink ejecting element by a capillary action or an external suction operation, and the ink pressurizing chamber 80 is provided.
2 is supplied. When the piezoelectric actuator 801 is deformed as indicated by a broken line in a state where the ink pressurizing chamber 802 is filled with ink, the pressure in the ink pressurizing chamber 802 increases,
Ink is ejected from an ink ejection port 803. An actual ink ejecting apparatus has a structure in which a plurality of elements described above are arranged in the x direction for high-speed printing.

[0005] As an ink ejecting apparatus in which a plurality of elements are arranged in the z direction which is the thickness direction of the piezoelectric actuator, there is an ink jetting apparatus disclosed in Japanese Patent Application Laid-Open No. 02-3311 shown in FIG. The ink ejecting apparatus includes a piezoelectric actuator section 910 made of a piezoelectric ceramic material 911,
The ink pressurizing chamber 915 and the cavity 917 are arranged in the z direction as shown in FIG. Further, the ink ejecting apparatus has an excitation electrode 912 and an ink ejecting port 916.

In the ink jet device having the structure shown in FIG. 18, it is difficult to reduce the length of the beam in the x direction to a certain extent or more because it is desired to increase the displacement of the piezoelectric actuator 801. In addition, there is a demand to reduce the distance between the elements in order to reduce interference between adjacent ink ejecting elements, and it is difficult to increase the array density of the elements. Therefore, high-speed and high-definition printing becomes difficult.

On the other hand, in the ink ejecting apparatus having the structure shown in FIG. 19, the arrangement density of elements can be increased for the following reasons. The piezoelectric actuator section 9 is operated by the action of the hollow section 917.
The transmission of the vibration of 10 to adjacent elements is reduced. ・ Even if the thickness (z direction) of the piezoelectric actuator section 910 is reduced, the displacement amount tends to increase. ・ Composed of integrally fired piezoelectric ceramic material Can be created with high accuracy

[0008]

However, with the above-described structure, the piezoelectric ceramic material 911 constituting the ink pressurizing chamber 915 comes into direct contact with the ink for a long period of time, and the piezoelectric actuator 910 However, there is a problem that the characteristics of the device deteriorate. Thereby, 1)
The high definition of the printed matter cannot be maintained, and 2) the element is damaged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a liquid ejecting apparatus and a method for manufacturing the liquid ejecting apparatus, which prevent deterioration of the characteristics of the apparatus due to ink and improve the reliability and durability of the apparatus. Aim.

[0010]

A liquid ejecting apparatus according to the present invention comprises:
This is a liquid ejecting apparatus in which a plurality of liquid ejecting elements are arranged. The liquid ejecting element has a liquid ejecting port, and forms a liquid pressurizing chamber for filling the liquid ejected from the liquid ejecting port, and one of inner walls of the liquid pressurizing chamber, and pressurizes the liquid pressurizing chamber. A liquid pressurizing unit for ejecting the liquid, and a liquid pressurizing unit. The liquid pressurizing unit is disposed adjacent to the liquid pressurizing unit. And a pressure buffer chamber for buffering. A portion of the liquid pressurizing section that comes into contact with the liquid in the liquid pressurizing chamber is made of a material that is not eroded by the liquid.

[0011] Preferably, the liquid pressurizing section is constituted by a piezoelectric actuator made of a piezoelectric material.

At least one constituent element of the piezoelectric material may be lead.

The material which is not eroded by the liquid may be any of a resin material, a ceramic material, and a metal material.

According to the manufacturing method of the present invention, there is provided a liquid pressurizing chamber having a liquid jetting port for filling the liquid jetted from the liquid jetting port, and one of the inner walls of the liquid pressurizing chamber, wherein A method for manufacturing a liquid ejecting apparatus in which a plurality of liquid ejecting elements each having a liquid pressurizing unit for ejecting a liquid by pressurizing a pressure chamber are arranged, wherein a portion of the liquid pressurizing unit which is in contact with the liquid pressurizing chamber is provided. And a step of bonding the liquid pressurizing section and a member for forming the liquid pressurizing chamber with an adhesive. Preferably, as an adhesive,
Use a sheet-like adhesive with high thixotropy.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a liquid ejecting apparatus according to the present invention will be described with reference to the accompanying drawings. The liquid ejecting apparatus described below is used for a printing apparatus or the like, and is an apparatus that ejects a liquid (ink) to a printing sheet in order to print a desired character or image on the printing sheet.

(First Embodiment) A first embodiment of a liquid ejecting apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of the liquid ejection apparatus according to the first embodiment.
FIG. 2 is a cross-sectional view on the z-plane, and FIG. 2 is a cross-sectional view on the yz plane. However, the x, y, and z axes correspond to the width direction (normally, the short side direction), the length direction (normally, the long side direction), and the thickness direction of the piezoelectric actuator 111 (the same applies to the following description). FIGS. 1 and 2 show the configuration of two liquid ejecting elements P1 and P2 constituting the liquid ejecting apparatus.
In the figure, a portion surrounded by a broken line corresponds to one liquid ejecting element. The liquid ejecting apparatus is configured by arranging a plurality of such liquid ejecting elements.

The liquid ejecting element P1 has a piezoelectric actuator 111 serving as a liquid pressurizing section. Piezoelectric actuator 1
11 is a portion 101 of a piezoelectric ceramic subjected to polarization processing.
And an unpolarized piezoelectric ceramic portion 102 in the same layer as the portion 101, and excitation electrodes 103a and 103b.
And a diaphragm 104 made of unpolarized piezoelectric ceramic;
And a resin layer 105 having ink resistance. More specifically, the polarized piezoelectric ceramic portion 10
1 and excitation electrodes 103b and 103a are connected above and below the unpolarized piezoelectric ceramic portion 102, respectively.
A diaphragm 104 is provided on a surface opposite to the surfaces 1 and 102. In addition, a resin layer 105 having ink resistance is provided on a surface of the vibration plate 104 opposite to the electrode 103b. The resin layer 105 is made of, for example, an epoxy resin.

The liquid ejecting element P1 further includes a liquid pressurizing chamber 11
2 is provided. The liquid pressurizing chamber 112 includes a liquid pressurizing chamber side wall 106 made of piezoelectric ceramic, a liquid pressurizing chamber bottom 107 made of piezoelectric ceramic, and a surface of the piezoelectric actuator 111 formed by the resin layer 105. Further, the liquid ejecting element P1 includes a pressure buffer chamber 113. Pressure buffer chamber 113
Is a pressure buffer chamber side wall 108 made of piezoelectric ceramic, the liquid pressurizing chamber bottom surface 107, and the piezoelectric actuator 1
11 is formed on the surface opposite to the resin layer 105.
The liquid pressurizing chamber 112 is provided on the opposite side of the pressure buffer chamber 113 with the piezoelectric actuator 111 interposed therebetween. As described above, the side surface of the piezoelectric actuator 111 on which the liquid pressurizing chamber 112 is formed is formed of the resin layer 104 and protected from the liquid. Has been prevented.

As shown in FIG. 2, the liquid ejecting element P
1 is a liquid ejection port 114 from which a liquid (ink) is ejected;
A liquid jet plate 110 provided with a liquid jet port 114;
A liquid inlet 109 for introducing a liquid (ink). Although not shown for the sake of convenience, the excitation electrodes 103a and 103b of each liquid ejecting element have electrodes led out of the ejecting element, and a voltage can be applied to both ends thereof. In the present embodiment, lead titanate or lead zirconate titanate is used as the piezoelectric ceramic material.

Next, the operation of the liquid ejecting apparatus will be described. First, the operating principle of the piezoelectric actuator 111 is shown in FIG.
This will be described with reference to FIG. FIG. 3 is a diagram showing the operation of the piezoelectric substrate alone, and FIG. 4 is a diagram showing the operation of a unimorph type piezoelectric actuator. The operation principle of the piezoelectric actuator 111 shown in FIGS. 1 and 2 is basically the same as the operation principle of the piezoelectric actuator described with reference to FIG. In FIG. 3, excitation electrodes 503b and 503a are provided on upper and lower main surfaces of a polarized piezoelectric substrate 501. In FIG. 4, the piezoelectric actuator includes a polarized piezoelectric substrate 501 having excitation electrodes 503b and 503a provided on upper and lower main surfaces, and a vibration provided on the surface of the excitation electrode 503a opposite to the piezoelectric substrate 501. Board 50
4

Referring to FIG. 3, when a pulsed electric field is applied in the thickness direction of piezoelectric substrate 501, that is, excitation electrode 5
When a voltage is applied between the driving electrode 03a and the excitation electrode 503b,
It has the property of expanding and contracting in the x direction (the same applies to the y direction). For example, when a negative electric field is applied to the piezoelectric substrate 501 with reference to the potential of the electrode 503a, the piezoelectric substrate 501 contracts as shown in FIG. 3B, and when a positive electric field is applied, the piezoelectric substrate 501 becomes as shown in FIG. Has the property of stretching.
By alternately applying a positive and a negative electric field to the piezoelectric substrate having such characteristics, the expansion and contraction operation of the piezoelectric substrate can be obtained. Such a mode of operation is referred to as “length vibration mode”.

Next, the operation of the piezoelectric actuator will be described with reference to FIG. In FIG. 4A, the excitation electrode 50 is used.
When a pulse voltage is applied between 3a and the excitation electrode 503b,
When a negative electric field is applied to the piezoelectric substrate 501 with reference to the potential of the electrode 503a, the piezoelectric substrate 501 tries to shrink, but the diaphragm 504 tries to maintain the state.
As shown in (b), the piezoelectric actuator bends in a downwardly convex shape. Conversely, when a positive electric field is applied, the piezoelectric substrate 501 tends to expand, but the diaphragm 504 tries to maintain the state. Therefore, as shown in FIG. Bends. Thus, the bending operation of the piezoelectric actuator can be obtained by alternately applying the plus and minus electric fields. Such a mode of operation is referred to as a “flexural vibration mode”.

The liquid ejecting operation of the liquid ejecting apparatus shown in FIGS. 1 and 2 will be described with reference to FIG. In FIG. 5, (a) is a cross section of the liquid ejecting apparatus on the xz plane,
(B) is a figure showing a section on the yz plane. When a pulse voltage is applied so that the piezoelectric actuator 111 performs the above-described bending operation, the piezoelectric actuator 111 is deformed in a convex shape toward the liquid pressurizing chamber 112 as shown in FIGS. The pressure in the pressure chamber 112 increases, and droplets (ink) are ejected from the liquid ejection ports 114. After the injection, the pressure in the liquid pressurizing chamber 112 decreases, so that the liquid inlet 1
From 09, the liquid pressurizing chamber 112 is filled with liquid (ink).

Next, a method for manufacturing the liquid ejecting apparatus according to the present embodiment will be described with reference to FIGS. In addition,
The method for manufacturing a liquid ejecting apparatus includes five steps from step A to step E.

[Step A]: Referring to FIG. 6, an electrode material is applied on a piezoelectric ceramic green sheet by printing to form a diaphragm sheet including diaphragm 104 and excitation electrode 103b (see FIG. 6). 6 (a)).
Piezoelectric ceramic (unpolarized portion) 102 and excitation electrode 1
A piezoelectric sheet made of 03a is prepared (see FIG. 6B). Next, a sheet forming the pressure buffer chamber side wall 108 is cut out by punching (see FIG. 6C). A sheet for forming the liquid pressurizing chamber bottom surface 107 is prepared (see FIG. 6D). A sheet forming the liquid pressure chamber side wall 106 is prepared in the same manner as the pressure buffer chamber side wall 108 (see FIG. 6E). [Step B]: As shown in FIG. 7, the sheets shown in FIGS. 6A to 6E are stacked in that order. However, FIG.
A removable mold 115 is inserted in the gap between the sheet forming the pressure buffer chamber side wall 108 shown in FIG. 6C and the sheet forming the liquid pressure chamber side wall 106 shown in FIG. The mold 115 is removed after pressing. [Step C]: The sheets laminated as described above are fired at a high temperature, and as shown in FIG. 8, the surface of the diaphragm 104 opposite to the surface on which the electrode 103b is provided is covered. The resin layer 105 is provided by applying an adhesive as described above. In forming the resin layer 105, a material having high ink resistance such as an epoxy-based sheet adhesive (a sheet-like adhesive having a high thixotropy) is used. In addition, the sheet adhesive can easily suppress variations in thickness, it is difficult to form a thin portion of the adhesive, and is excellent in ink-resistant protection performance. [Step D]: As shown in FIG. 9, the resin layer 10
5, a DC voltage is applied between the excitation electrodes 103a and 103b of the piezoelectric ceramic (unpolarized portion) 102 to partially polarize the piezoelectric ceramic, thereby forming a polarized portion 101 of the piezoelectric ceramic. [Step E]: As shown in FIG. 10, the device manufactured as described above is separated using a wire saw or the like, and the liquid ejection plate 110 or the like is attached to the side surface.

The cutting step in step E can be omitted. Rather, in order to increase the number of elements and realize high-speed printing, the liquid ejection port plate 110 and the like are attached to the configuration shown in FIG. It is preferable to use it. Further, the liquid pressurizing chamber 11
2. Although the mold 115 is used to manufacture the pressure buffer chamber 113, a resin or the like that can be removed during firing may be embedded in this portion in step B.

The features of the liquid ejecting apparatus according to this embodiment, which can be manufactured as described above, will be described in comparison with Comparative Example 1 (details will be described later).

The liquid pressurizing chamber 1 of the liquid ejecting apparatus according to the present embodiment.
12 is filled with ink to form an unused state of the liquid ejecting apparatus. After leaving for a certain period of time, the piezoelectric actuator 1
11 to drive the ink, eject the ink, form a printing state,
In that state, it is left for a certain time. FIG. 11 shows a plot of the relationship between time, the remaining ratio of the liquid ejecting element, and the displacement of the piezoelectric actuator 111, by alternately repeating the unused state and the printing state. Note that, in the figure, the horizontal axis is a logarithmic scale. Here, the residual rate is the initial number n0 of liquid ejecting elements, the liquid ejecting elements are not driven due to damage or the like, or the displacement amount is 50% of the initial displacement amount ξ0.
When the element in the following state is defined as n1, it is expressed by the following equation. Residual rate = (n0−n1) / n0 (1)

In FIG. 11, broken lines indicate values of the residual ratio and the displacement according to Comparative Example 1. As described above, in the liquid ejecting apparatus of the present embodiment, the provision of the resin layer 105 prevents the piezoelectric ceramic portion of the piezoelectric actuator 111 from directly touching the ink, so that the piezoelectric actuator 111 is not deteriorated, and the residual ratio is substantially reduced. It is possible to suppress the decrease in the displacement amount to 100% and the displacement amount to 5% or less. Characteristic deterioration of the piezoelectric actuator 111 in Comparative Example 1, or
The main cause of breakage is the elution of lead components into the ink. As a result, the piezoelectric characteristics are reduced, that is, the amount of displacement obtained with the same applied voltage is reduced. In addition, the eluted lead portions become voids, into which ink penetrates. This phenomenon is sequentially repeated, and a hole extending in the z direction of the piezoelectric actuator 111 is formed, and the element is damaged. When this hole further extends and reaches the excitation electrode portion, the electrode is degraded due to an electrochemical reaction, and the piezoelectric ceramic portion is further degraded. However, in this test, as the piezoelectric ceramic material,
Although lead titanate was used, even when lead zirconate titanate was used as the piezoelectric ceramic material, substantially the same results as those shown in FIG. 11 were obtained.

As described above, as in the structure of the liquid ejecting apparatus according to the present invention, the resin layer 105 is provided so that the piezoelectric ceramic portion of the piezoelectric actuator 111 does not directly contact the ink. A small and highly reliable liquid ejecting apparatus can be realized. Further, according to the manufacturing method of the liquid ejecting apparatus of the present invention, the bonding between the side wall 106 of the liquid pressurizing chamber and the vibration plate 104 and the protection of the piezoelectric actuator 111 against ink can be performed at the same time, and the manufacturing cost can be reduced. Further, since a liquid ejecting apparatus having a large number of liquid ejecting elements can be manufactured at a time, the cost per element is significantly reduced. In addition, the combined use of lamination and firing greatly improves the production yield.

(Embodiment 2) A second embodiment of the liquid ejecting apparatus according to the present invention will be described with reference to FIG.
FIG. 12 shows four liquid ejecting elements P1 to P4. The liquid ejecting element according to the present embodiment differs from the liquid ejecting element according to the first embodiment in that a liquid pressurizing chamber 112, a piezoelectric actuator 111a,
The arrangement of the pressure buffer chamber 113 is different. That is, two liquid ejecting elements are paired, and the pressure buffer chamber 113 is shared between the liquid ejecting elements. Therefore, the structure has a higher arrangement density than the structure of the first embodiment. As in the first embodiment, the piezoelectric actuator 111a includes a piezoelectric ceramic portion 101 that has been subjected to polarization processing, an unpolarized piezoelectric ceramic portion 102, excitation electrodes 103a and 103b, and a diaphragm made of unpolarized piezoelectric ceramic. 104 and a resin layer 105 having ink resistance. In this embodiment, the same operation and effect as those of the first embodiment are obtained.

(Embodiment 3) A third embodiment of the liquid ejecting apparatus according to the present invention will be described with reference to FIG. This embodiment is different from the above-described embodiment in that the piezoelectric actuator 111b has a bimorph structure. That is, the liquid ejecting apparatus according to the present embodiment has a structure in which the polarized piezoelectric ceramic 101 is used instead of the diaphragm 104 in the above-described embodiment. In the bimorph structure, when a voltage is applied, when the upper layer of the two layers of piezoelectric ceramic (polarized portion) 101 is extended, the lower layer is contracted and the opposite state is alternately repeated to obtain a bending operation. This is the structure that is used. With this structure, a larger displacement can be obtained with the same applied voltage than the piezoelectric actuator 111 described in the first embodiment, and the voltage of the device can be reduced. In the case of such a structure, the resin layer 1 is formed as in Comparative Example 2 (details will be described later).
If there is no 05, the element is destroyed only by driving the piezoelectric actuator 111 in a state where the ink is filled in the liquid pressurizing chamber 112, and the device does not function at all. FIG.
By using the structure described above, even when the test described in the first embodiment is performed, the residual ratio is almost 100%, and the decrease in the displacement is 5%.
It is possible to be within.

(Embodiment 4) A fourth embodiment of the liquid ejecting apparatus according to the present invention will be described with reference to FIG. In the present embodiment, the piezoelectric actuator 111c is
The piezoelectric layer has a four-layer multimorph structure. The operation of the multimorph structure is the same as the operation when two bimorphs are stacked, and the upper layer expands, contracts, expands, contracts, and
The contraction → elongation → contraction → elongation is repeated alternately. With this structure, when the total thickness is the same, a larger displacement can be obtained with the same voltage than in the piezoelectric actuator 111b described in the third embodiment, and the voltage of the device can be reduced. In the liquid ejecting apparatus of the present embodiment, the resin layer 105
When the structure is removed, the same problem as that described in Comparative Example 2 occurs. Accordingly, by providing the resin layer 105, even in the case of performing the test described in the first embodiment, the residual ratio can be set to almost 100% and the decrease in the displacement can be kept within 5% as in the third embodiment. It becomes possible.

In the first to fourth embodiments described above, the resin layer 105 is formed using an epoxy resin, but the resin layer 105 is not limited to this. For example, the same effect can be obtained by using a resin such as a polyimide-based, polyurethane-based, polyamide-based, or silicone-based resin or an epoxy-based resin. That is, it is sufficient that the ink has sufficient resistance to the ink.

(Fifth Embodiment) A fifth embodiment of the liquid ejecting apparatus according to the present invention will be described with reference to FIG. The liquid ejecting apparatus according to the present embodiment has the same structure as the liquid ejecting apparatus according to the second embodiment. However, the liquid pressurizing chamber side wall 12 forming the liquid pressurizing chamber 112 filled with the liquid is used.
6 and the liquid pressurizing chamber bottom surface 127 are different from those described above in that the material is stainless steel. Also, the piezoelectric actuator 1
The diaphragm 124, which is a component of the liquid pressurizing chamber 112, is also made of stainless steel. These are fixed by diffusion bonding. Further, the diaphragm 12
4 is an excitation electrode 103b and a piezoelectric ceramic 101;
102 and an adhesive 125.

The liquid ejecting apparatus according to the present embodiment is different from the above-described liquid ejecting apparatus in that a stainless steel diaphragm 124 plays a role as a protective layer for ink instead of the resin layer 105. Stainless steel has higher reliability with respect to ink resistance than the resin (for example, epoxy resin) described in the first embodiment. Therefore, the reliability of the liquid ejecting apparatus can be further improved.

In this embodiment, stainless steel is used as the material of the diaphragm 124 which also functions as a protective layer for ink. However, the present invention is not limited to stainless steel, and other metal materials having resistance to ink may be used.

(Embodiment 6) A sixth embodiment of the liquid ejecting apparatus according to the present invention will be described. The structure of the liquid ejecting apparatus according to the present embodiment is the same as that shown in FIG. However, the liquid pressurizing chamber side wall 126 and the liquid pressurizing chamber bottom surface 127 which form the liquid pressurizing chamber 112 filled with the liquid.
Is different from the above-mentioned one in that it is made of a multilayer ceramic made of zirconia. Also, the piezoelectric actuator 1
The 11d diaphragm 124 is made of a laminated ceramic made of zirconia. Even when the diaphragm 124 and the like are made of a laminated ceramic made of zirconia in this manner,
The same ink-resistant reliability as in the fifth embodiment can be obtained, and a liquid ejecting element can be realized at low cost.

In this embodiment, the diaphragm 124,
Although zirconia was used as a laminated ceramic material for forming the liquid pressure chamber side wall 126 and the liquid pressure chamber bottom 127,
Similar effects can be obtained by using other materials such as alumina. That is, any other ceramic material having ink resistance can be used.

In the first to sixth embodiments, ink having a pH of about 8 to 9.5 is mainly used. Therefore, if ink having a pH of 8 or less is used, a higher effect can be obtained.

In the first to sixth embodiments, a case has been described in which a piezoelectric ceramic material containing lead as a constituent material is used as a constituent material of the piezoelectric actuator. However, barium titanate or the like containing no lead is used. Even when an electrostrictive material or other non-lead-based piezoelectric material is used, the ink may cause deterioration in characteristics, breakage, and the like. Even in this case, the effects of the liquid ejecting apparatus of the present invention and the method of manufacturing the same can be sufficiently obtained.

Comparative Example 1 Hereinafter, a first comparative example of the above-described liquid ejecting apparatus according to the present invention will be described with reference to FIG. The liquid ejecting apparatus of the comparative example shown in FIG. 16A has a structure in which the resin layer 105 is removed from the structure described in Embodiment 1 (see FIG. 1). In this comparative example, characteristics of a liquid ejecting apparatus having a structure in which a piezoelectric actuator 111 made of a piezoelectric ceramic directly contacts a liquid are verified.

In the comparative test, ink was introduced into the liquid pressurizing chamber 112 of the liquid ejecting element having the structure shown in FIG.
Then, the piezoelectric actuator 111x was periodically driven for a certain period of time to measure the remaining rate of the element and the amount of displacement of the element. FIGS. 16B and 16C show the results. However, the time on the horizontal axis is on a logarithmic scale.

<Comparative Example 2> A second comparative example will be described with reference to FIG. In this comparative example, the piezoelectric actuator 111y in the liquid ejecting element has a bimorph structure,
This is for verifying the characteristics of a liquid ejecting apparatus having a structure in which the excitation electrode 103c is in direct contact with the liquid (ink) because it does not have a resin layer or the like as in the above embodiment. In the case of such a structure of the comparative example, when the piezoelectric actuator 111y is driven, the excitation electrode 103c
Of the piezoelectric ceramic 101 in the polarized portion and destruction of the piezoelectric ceramic 102 in the non-polarized portion occur.

As described above, according to the present invention, a highly reliable liquid ejecting apparatus having a high density arrangement can be realized. Further, according to the method for manufacturing a liquid ejecting apparatus of the present invention, it is possible to manufacture a highly reliable liquid ejecting apparatus arranged at high density with good yield and at low cost.

The present invention is applicable not only to general inkjet printers but also to facsimile machines, word processors,
It may be used in combination with a device having a printing device such as a register. Further, the present invention can also be applied as an apparatus used in a production line, such as engraving and drawing on industrial products and application of a chemical solution.
The recording medium of the present invention is not limited to paper, but may be metal, glass, resin, pottery, wood, cloth, leather, or the like.

[0047]

According to the present invention, the portion of the liquid pressurizing portion which is in contact with the liquid pressurizing chamber is made of a material which is not eroded by the liquid, thereby increasing the resistance of the liquid pressurizing portion to the liquid. Therefore, reliability and durability of the liquid ejecting apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram (xz cross section) illustrating a structure of a liquid ejecting apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram (a yz cross section) showing a structure of the liquid ejecting apparatus according to the first embodiment of the present invention.

FIG. 3 is a view for explaining a length vibration state of a piezoelectric substrate.

FIG. 4 is a view showing the operation principle of a unimorph type piezoelectric actuator.

FIG. 5 is a diagram illustrating the operation of the liquid ejecting apparatus according to the first embodiment.

FIG. 6 is a view showing a method of manufacturing the liquid ejecting apparatus according to the first embodiment (step A).

FIG. 7 is a view illustrating a method of manufacturing the liquid ejecting apparatus according to the first embodiment (step B).

FIG. 8 is a view illustrating a method of manufacturing the liquid ejecting apparatus according to the first embodiment (step C).

FIG. 9 is a view illustrating a method of manufacturing the liquid ejecting apparatus according to the first embodiment (step D).

FIG. 10 is a view illustrating a method of manufacturing the liquid ejecting apparatus according to the first embodiment (step E).

FIG. 11 is a view showing test results of the liquid ejecting apparatus according to the first embodiment.

FIG. 12 is a diagram illustrating a structure of a liquid ejecting apparatus according to a second embodiment of the present invention.

FIG. 13 is a diagram illustrating a structure of a liquid ejecting apparatus according to a third embodiment of the present invention.

FIG. 14 is a diagram illustrating a structure of a liquid ejecting apparatus according to a fourth embodiment of the present invention.

FIG. 15 is a diagram illustrating a structure of a liquid ejecting apparatus according to a fifth embodiment of the present invention.

FIG. 16 is a diagram showing a first comparative example for the liquid ejecting apparatus according to the present invention.

FIG. 17 is a view showing a second comparative example for the liquid ejecting apparatus according to the present invention.

FIG. 18 is a diagram showing a structure of a conventional liquid ejecting apparatus.

FIG. 19 is a view showing a structure of a conventional liquid ejecting apparatus.

[Explanation of symbols]

Reference Signs List 101 piezoelectric ceramic (polarized part) 102 piezoelectric ceramic (non-polarized part) 103a, 103b excitation electrode 104 diaphragm (non-polarized piezoelectric ceramic) 105 resin layer 106 liquid pressurizing chamber side wall 107 liquid pressurizing chamber bottom 108 pressure Buffer chamber side wall 109 Liquid introduction port 110 Liquid ejection port plate 111, 111a to 111d Piezoelectric actuator (liquid pressurizing unit) 112 Liquid pressurization chamber 113 Pressure buffer chamber 114 Liquid ejection port 115 type 124 Vibration plate (stainless steel, ceramic material)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuyuki Okano 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Kazuhide Shioya 1006 Kadoma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. 1006 Kadoma Kadoma, Kadoma, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd. 2C057 AF70 AF93 AG44 AG48 AG55 AP02 AP22 AP25 AP57 AQ10 BA03 BA14

Claims (8)

[Claims] 1. A liquid ejecting apparatus having a plurality of liquid ejecting elements arranged therein, said liquid ejecting element having a liquid ejecting port, and a liquid pressurizing chamber for filling a liquid ejected from the liquid ejecting port. A liquid pressurizing unit that constitutes one of the inner walls of the liquid pressurizing chamber, pressurizes the liquid pressurizing chamber to eject liquid, and is disposed adjacent to the liquid pressurizing unit, and A pressure buffer chamber disposed on a side opposite to the liquid pressurizing chamber with respect to the liquid pressurizing section and configured to buffer pressure during pressurization; A liquid ejecting apparatus characterized in that a portion that comes into contact with the liquid is made of a material that is not eroded by the liquid. 2. The liquid ejecting apparatus according to claim 1, wherein the liquid pressurizing unit is a piezoelectric actuator made of a piezoelectric material. 3. The liquid ejecting apparatus according to claim 2, wherein at least one constituent element of the piezoelectric material is lead. 4. The liquid ejecting apparatus according to claim 1, wherein the material that is not eroded by the liquid is a resin material. 5. The liquid ejecting apparatus according to claim 1, wherein the material that is not eroded by the liquid is a ceramic material. 6. The liquid ejecting apparatus according to claim 1, wherein the material not eroded by the liquid is a metal material. 7. A liquid pressurizing chamber having a liquid jetting port and filling a liquid jetted from the liquid jetting port, and one of inner walls of the liquid pressurizing chamber, and the liquid pressurizing chamber is pressurized. A method for manufacturing a liquid ejecting apparatus in which a plurality of liquid ejecting elements each having a liquid pressurizing section for ejecting liquid are arranged, wherein a portion of the liquid pressurizing section that is in contact with the liquid pressurizing chamber is covered. A step of applying an adhesive to the substrate, and a step of bonding the liquid pressurizing portion and a member for forming the liquid pressurizing chamber with the adhesive. . 8. The method according to claim 7, wherein a sheet-like adhesive having a high thixotropy is used as the adhesive.