JP6930461B2 - Liquid discharge head, liquid discharge unit and device that discharges liquid - Google Patents

Description

The present invention relates to a liquid discharge head, a liquid discharge unit, and a device for discharging a liquid.

Conventionally, a recording device equipped with an inkjet head and an inkjet head that generate pressure fluctuations in a liquid chamber (also referred to as an individual liquid chamber, a pressurized liquid chamber, etc.) and eject a liquid from a minute nozzle formed in the liquid chamber has been known. Has been done.

As a method of generating pressure fluctuation in the individual liquid chamber of the inkjet head, there are a method of installing a heater in the individual liquid chamber and vaporizing the liquid to utilize the pressure fluctuation, and a method of installing an actuator corresponding to the individual liquid chamber. Are known. Methods using an actuator include a piezoelectric element method and an electrostatic method depending on the type of actuator.

Among these, in the piezoelectric element method, there is a problem that the ejection characteristics vary among nozzles in the same head due to variations in the characteristics of the piezoelectric body and variations due to the dimensions of the vibrating portion constituting a part of the actuator.

Such variation in discharge characteristics occurs because δ × L = ΔW (referred to as exclusion volume) obtained by multiplying the displacement characteristics δ by the length L of the actuator differs between the nozzles. For example, when the displacement characteristic δ becomes large at the nozzle end in the head, the exclusion volume ΔW on the nozzle end side becomes large, and the discharge speed, which is one of the discharge characteristics, becomes large at the nozzle end in the head. It ends up. For example, as shown in FIG. 3D, the ejection speed increases on the nozzle end side.

To solve such a problem, for example, Patent Documents 1 to 3 have been proposed for the purpose of making the discharge characteristics uniform.
In Patent Document 1, the driving area of the piezoelectric material active portion is adjusted, and in Patent Document 2, the area of the pressure chamber is made larger in the discharge non-uniform region of the end region in the nozzle row than in the uniform region of the end inner region. doing. Patent Documents 1 and 2 disclose that the dimensions of the individual liquid chambers are changed according to the variation in the displacement characteristic δ measured in advance to make the displacement characteristic δ uniform. Further, in Patent Document 2, by shortening the actuator electrode of the nozzle having a large displacement characteristic δ, the exclusion volume ΔW is made uniform as a result.
In Patent Document 3, nozzles having different opening diameters are provided, and the size of the nozzle is changed according to the variation in the exclusion volume ΔW due to the variation in the displacement characteristic δ to keep the discharge speed constant.

As described above, conventionally, the variation in the discharge speed between the nozzles has been suppressed by making the exclusion volume ΔW uniform or changing the individual liquid chambers and the opening diameters of the nozzles. However, if an attempt is made to suppress the variation in the discharge rate by such a method, the diaphragm compliance varies between the nozzles, and the resonance period of the individual liquid chambers varies between the nozzles. If the resonance period of the individual liquid chambers deviates between the nozzles, the discharge speed will vary when the drive waveform is changed, for example, and it will be difficult to obtain uniform discharge characteristics. Further, when the ejection speed varies from wafer to wafer, the displacement characteristic δ does not always increase at the nozzle end in the head, and even if the above method is used, it is difficult to suppress the variation in the ejection speed in the head. In this case, for example, it is necessary to take measures such as suppressing variation among wafers.

In view of the above problems, it is an object of the present invention to provide a liquid discharge head capable of obtaining a high-quality image by suppressing variations in the resonance period and discharge speed of individual liquid chambers.

In order to solve the above problems, the liquid discharge head of the present invention has a nozzle substrate provided with a plurality of nozzles and an individual liquid chamber that communicates with the nozzles and has a length and a short side in the surface direction of the nozzle substrate. A vibrating plate forming at least a part of the individual liquid chamber, a lower electrode formed on the vibrating plate, a piezoelectric body formed on the lower electrode, and an upper electrode formed on the piezoelectric body. When a piezoelectric element having a piezoelectric element and an insulating film formed on the vibrating plate are provided, and the individual liquid chamber, the piezoelectric body, and the upper electrode are used as discharge units, the discharge unit is the short side of the individual liquid chamber. When arranged in the direction and viewed from the direction perpendicular to the surface of the nozzle substrate, at least the area of the upper electrode and the area of the insulating film in the portion overlapping the individual liquid chambers differ between the discharge units. It is characterized in that there is one and there is a negative correlation between the discharge units.

According to the present invention, it is possible to provide a liquid discharge head capable of obtaining a high-quality image by suppressing variations in the resonance period and discharge speed of individual liquid chambers.

It is sectional drawing in the lateral direction in the example of the liquid discharge head of this invention. It is sectional drawing in the longitudinal direction in an example of the liquid discharge head of this invention. It is a plan view of the liquid discharge head of Reference Example 1. FIG. It is a plot figure (a)-(d) of various characteristics in the liquid discharge head of Reference Example 1. It is a figure (a) which shows an example of a discharge speed distribution in a liquid discharge head, and is a figure (b) which shows an example of a discharge speed distribution in an actuator wafer. It is a plan view of the liquid discharge head of Reference Example 2. FIG. It is a plot figure (a)-(d) of various characteristics in the liquid discharge head of Reference Example 2. It is a figure which shows an example of a drive waveform and a meniscus vibration. It is a plane schematic diagram in an example of the liquid discharge head of this invention. It is a plot figure (a)-(d) of various characteristics in an example of a liquid discharge head of this invention. It is a longitudinal sectional view (a) and an enlarged sectional view (b) in an example of the liquid discharge head of this invention. Other longitudinal sectional views (a) and enlarged sectional views (b) and (c) of an example of the liquid discharge head of the present invention. It is a figure which shows an example of the relationship between the upper electrode and the first insulating film in an example of a liquid discharge head of this invention. It is a figure which shows another example of the discharge speed distribution in a liquid discharge head. It is a plane schematic diagram (a) and (b) in another example of the liquid discharge head of this invention. It is sectional drawing in the longitudinal direction in another example of the liquid discharge head of this invention. It is a figure which shows an example of the relationship between the upper electrode and the second insulating film in another example of the liquid discharge head of this invention. It is sectional drawing in the longitudinal direction in another example of the liquid discharge head of this invention. It is a plane schematic diagram in another example of the liquid discharge head of this invention. It is sectional drawing in the longitudinal direction in another example of the liquid discharge head of this invention. It is a plane schematic diagram in another example of the liquid discharge head of this invention. It is sectional drawing in the longitudinal direction in another example of the liquid discharge head of this invention. It is sectional drawing (a)-(g) in the longitudinal direction for demonstrating an example of the manufacturing method of the liquid discharge head of this invention. It is sectional drawing (a)-(g) in the longitudinal direction for demonstrating an example of the manufacturing method of the liquid discharge head of this invention. It is a schematic diagram which shows an example of the apparatus which discharges a liquid which concerns on this invention. It is a schematic diagram which shows another example of the apparatus which discharges a liquid which concerns on this invention. It is a schematic diagram which shows an example of the liquid discharge unit which concerns on this invention. It is a schematic diagram which shows another example of the liquid discharge unit which concerns on this invention.

Hereinafter, the liquid discharge head, the liquid discharge unit, and the device for discharging the liquid according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments shown below, and can be modified within the range conceivable by those skilled in the art, such as other embodiments, additions, modifications, and deletions. However, as long as the action and effect of the present invention are exhibited, it is included in the scope of the present invention.

(Liquid discharge head)
The liquid discharge head of the present invention includes a nozzle substrate provided with a plurality of nozzles, an individual liquid chamber that communicates with the nozzles and has a length and a short side in the plane direction of the nozzle substrate, and at least the individual liquid chambers. A piezoelectric element having a vibrating plate forming a part thereof, a lower electrode formed on the vibrating plate, a piezoelectric body formed on the lower electrode, and an upper electrode formed on the piezoelectric body, and the vibrating plate. When the individual liquid chamber, the piezoelectric body, and the upper electrode are used as discharge units, the discharge units are arranged in the lateral direction of the individual liquid chambers, and the nozzle substrate is provided. The area of the upper electrode and the area of the insulating film in the portion overlapping the individual liquid chambers are different between the discharge units at least one when viewed from the direction perpendicular to the plane of the discharge unit, and the discharge It is characterized by having a negative correlation between units.

The liquid discharge head of the present invention is suitably used for an inkjet head and an inkjet recording device. Examples of application fields include an inkjet head that ejects a liquid resist as a droplet, an inkjet head that ejects a DNA sample as a droplet, and the like.

<First Embodiment>
<< Basic configuration >>
An embodiment of the liquid discharge head according to the present invention will be described. Here, first, the basic configuration of the liquid discharge head of the present embodiment will be described. The liquid discharge head according to this embodiment is shown in FIGS. 1 and 2. FIG. 1 is a cross-sectional view of the individual liquid chamber 110 in the lateral direction, and FIG. 2 is a cross-sectional view of the individual liquid chamber 110 in the longitudinal direction.

The individual liquid chamber 110 has a longitudinal direction and a short side in the surface direction of the nozzle substrate 300, and hereinafter, when simply referred to as a longitudinal direction and a short side direction, the individual liquid chamber 110 has a longitudinal direction and a short side, respectively. It means the direction of the hand. Further, the piezoelectric body 103 and the upper electrode 104 of the present embodiment also have a longitudinal direction and a short side in the surface direction of the substrate, and the longitudinal direction and the lateral side of the piezoelectric body 103 and the upper electrode 104 are individual liquid chambers 110. It coincides with the longitudinal direction and the lateral direction of.

The liquid discharge head 1 of the present embodiment is configured by joining the holding substrate 200, the liquid chamber substrate 100 on which the piezoelectric element 105 is formed, and the nozzle substrate 300 provided with the nozzle 301. The holding substrate 200 is joined to the surface of the liquid chamber substrate 100 on which the piezoelectric element 105 is formed, and the nozzle substrate 300 is joined to the surface of the liquid chamber substrate 100 opposite to the surface on which the piezoelectric element 105 is formed. ..

The liquid (for example, ink) discharged from the nozzle 301 is supplied from the ink tank to the common liquid chamber 120 through the ink flow path 201. Next, it is supplied from the common liquid chamber 120 to the individual liquid chamber 110 via the fluid resistance portion 111.

The individual liquid chamber 110 is provided at a position corresponding to the nozzle 301, applies pressure to the liquid, and discharges the liquid from the nozzle 301. The individual liquid chamber 110 is partitioned by a liquid chamber partition wall 109, a diaphragm 101 is formed on the upper portion of the individual liquid chamber 110, and a lower electrode 102, a piezoelectric body 103, and an upper electrode 104 are laminated on the diaphragm 101. The piezoelectric element 105 is formed. The liquid is discharged from the nozzle 301 communicating with the individual liquid chamber 110 due to the pressure generated by driving the piezoelectric element 105.

In the present embodiment, the lower electrode 102 is a common electrode and the upper electrode 104 is an individual electrode, but the present invention is not limited to this, and the lower electrode 102 may be an individual electrode and the upper electrode 104 may be a common electrode.

The material of the liquid chamber substrate 100 can be variously selected from desired processability and physical properties. For example, it is preferable to use a silicon substrate that can use a photolithography method at 300 dpi (about 85 μm pitch) or more.

For the processing of the individual liquid chamber 110, for example, a wet etching method, a dry etching method, or the like can be used. As a result, the individual liquid chamber 110 side of the diaphragm 101 can be used as an etching stop layer by using a silicon dioxide film or the like, so that the height of the liquid chamber can be controlled with high accuracy.

As the diaphragm 101, for example, it is preferable to use a highly rigid material such as silicon, nitride, oxide, or carbide. Further, a laminated structure of these materials may be used.
As the lower electrode 102, for example, Pt, Ti, LaNiO ₃ (lantern nickate), SrRuO ₃ (strontium ruthenium oxide) and the like can be used.
As the piezoelectric body 103, for example, PZT (lead zirconate titanate) can be used.
As the upper electrode 104, for example, Pt, LaNiO ₃ , SrRuO _3, or the like can be used. Further, the thickness of the upper electrode 104 is not particularly limited and can be appropriately changed.

A plurality of rows (for example, four rows) of nozzles 301 for discharging liquid are arranged on the nozzle substrate 300.
The material of the nozzle substrate 300 can be variously selected according to the desired rigidity and workability. For example, metals or alloys such as SUS and nickel, inorganic materials such as silicon and ceramics, resin materials such as polyimide, and the like can be used.

As the processing method of the nozzle 301, the optimum method may be selected from the material characteristics of the nozzle substrate 300, the required accuracy, and the workability. For example, an electroforming plating method, an etching method, a press processing method, a laser processing method, and a photo. A lithography method or the like can be used. Further, the opening diameter of the nozzle 301, the number of nozzle arrangements, the arrangement density, and the like can also be set to a desired combination according to the required specifications.

The holding substrate 200 is joined to the liquid chamber substrate 100 on the side opposite to the nozzle substrate 300, whereby the rigidity of the liquid chamber substrate 100 can be ensured. The material of the holding substrate 200 is not particularly limited, but it is preferable to select a material having a coefficient of thermal expansion close to that of the liquid chamber substrate 100 in order to prevent warpage. For example, it is preferable to use glass, silicon, or a ceramic material such as _{SiO 2} , ZrO ₂ , Al ₂ O _3.

In the present embodiment, a wiring layer conductive to the piezoelectric element 105 is provided, and the wiring layer of the present embodiment includes a lower electrode wiring 112 connected to the lower electrode 102 of the piezoelectric element 105 and an upper electrode of the piezoelectric element 105. The upper electrode wiring 113 connected to 104 is shown. In addition, when it is described as a wiring layer, the lower electrode wiring 112 and the upper electrode wiring 113 will be described without distinction unless otherwise specified.

In the present embodiment, a first insulating film 106 (sometimes also referred to as an interlayer insulating film) is formed between the lower electrode 102 and the lower electrode wiring 112, and between the upper electrode 104 and the upper electrode wiring 113, respectively. As shown, the first insulating film 106 is formed at least between the wiring layer and the piezoelectric element 105. Further, the first insulating film 106 is partially provided with an opening as a contact hole, and the wiring layer is electrically connected to the piezoelectric element 105 via the lower electrode contact hole 122 and the upper electrode contact hole 123. ..

In the present embodiment, the lower electrode wiring 112 and the upper electrode wiring 113 have a second insulating film 107 (also referred to as a passivation film) formed on the side opposite to the side on which the first insulating film 106 is formed. .. As shown, the second insulating film 107 is formed at least on the wiring layer.

The first insulating film 106 and the second insulating film 107 are preferably formed so as not to interfere with the displacement of the diaphragm 101. Therefore, in the region where the piezoelectric element 105 is formed in a plan view, it is preferable not to form the piezoelectric element 105 in a place other than the vicinity of the contact hole. For example, as shown in FIG. 2, in the region where the piezoelectric element 105 is formed in a plan view, the first insulating film 106 is formed between the wiring layer and around the lower electrode contact hole 122 and the upper electrode contact hole 123. Has been done. Further, the second insulating film 107 is formed on the wiring layer and around the lower electrode contact hole 122 and the upper electrode contact hole 123.

Further, the upper electrode wiring 113 is connected to the drive IC 160, and the drive IC 160 selectively supplies the voltage supplied from the drive voltage control unit to the piezoelectric element 105 based on the print pattern to provide the piezoelectric element 105. Control.

<< Explanation of reference example >>
Here, reference examples 1 and 2 will be given to explain the details of the present embodiment.
The liquid discharge head according to Reference Example 1 will be described with reference to FIG. FIG. 3A is a schematic plan view of the liquid discharge head according to Reference Example 1, and FIG. 3B is a plot of various characteristics of the nozzles 1 to 6 of the head.

In FIG. 3A, a main part for explanation is shown, and the piezoelectric body 103, the upper electrode 104, the upper electrode wiring 113, and the first insulating film 106 formed on the liquid chamber substrate 100 are shown. On the other hand, the individual liquid chamber 110, the fluid resistance portion 111, and the ink flow path 201 are indicated by broken lines.

In FIG. 3A, six nozzles are shown, the nozzle number 1 is located on the end side, and the nozzle number 6 is located on the center side. Further, the individual liquid chamber 110, the piezoelectric body 103, and the upper electrode 104 are used as discharge units, and the discharge units are arranged in the lateral direction of the individual liquid chamber 110. In addition, there is a part where the nozzle is described as a discharge unit.

As described in the background technology, conventionally, in the piezoelectric element method, the ejection characteristics are different between the nozzles in the same head due to the variation in the characteristics of the piezoelectric body and the variation due to the dimensions of the vibrating part constituting a part of the actuator. There is a problem of variation.

Such variation in discharge characteristics occurs because δ × L = ΔW (referred to as exclusion volume) obtained by multiplying the displacement characteristics δ by the length L of the actuator differs between the nozzles. Here, the length L of the actuator is the length of the upper electrode 104 in the longitudinal direction of the individual liquid chamber 110, as shown in FIGS. 2 and 3A. Further, the displacement characteristic δ is the maximum displacement amount of the diaphragm 101 when the piezoelectric element 105 is driven, as shown in FIGS. 1 and 2. Hereinafter, the displacement characteristic δ may be simply referred to as the displacement δ.

As shown in FIG. 3B (a), in the liquid discharge head according to Reference Example 1, when the displacement δ of the nozzle 1 at the end is 100%, the displacement δ becomes smaller toward the nozzle 6. In such a head, as shown in FIGS. 3B (b) and 3B (d), the exclusion volume ΔW becomes smaller from the end side to the center side, and the discharge speed, which is one of the discharge characteristics, becomes smaller. ..

FIG. 4A shows an example of the discharge speed distribution in the liquid discharge head. FIG. 4A shows an example of the distribution of the discharge speed when the head of Reference Example 1 has nozzles 1 to 320, for example. As shown in the figure, the ejection speed is high at the end of the nozzle, and the ejection speed varies between the nozzles in the head. Various techniques have been conventionally proposed in order to solve such variations in discharge rate.

However, as described in Reference Example 2 below, even if the discharge rate can be adjusted, the rigidity compliance of the individual liquid chambers varies, so that the resonance period of the liquid chambers varies and uniform discharge characteristics are obtained. It's difficult.

Further, an example of the discharge speed distribution in the actuator wafer is shown in FIG. 4 (b). As shown in the figure, the ejection speed may vary for each actuator wafer. When the head is manufactured from such an actuator wafer, for example, the head corresponding to A in the drawing does not have the discharge speed distribution as shown in FIG. 4A, and the discharge speed distribution has an inclination. In this case, it is difficult to deal with it by the conventionally proposed technique, and it is necessary to take measures such as suppressing variation among wafers, for example.

Next, Reference Example 2, which is another reference example, will be described with reference to FIGS. 5 and 6. A plan view of the liquid discharge head according to Reference Example 2 is shown in FIG. 5A. FIG. 5A is a plan view similar to that of FIG. 3A, and FIG. 5B is a plot of various characteristics of nozzles 1 to 6 in the head in the same manner as in FIG. 3B.

In Reference Example 2, the length of the upper electrode 104 is changed between the nozzles. Here, the length of the upper electrode 104 is changed in the longitudinal direction. When the length of the upper electrode 104 is changed between the nozzles as shown in FIG. 5A, the exclusion volume ΔW becomes constant as shown in FIGS. 5B (b) and 5B (d), and the discharge rate can be made constant. .. However, as shown in FIG. 5B (c), the diaphragm compliance is not uniform.

Here, FIG. 6 shows an example of the driving waveform and the vibration state of the meniscus. The upper waveform in FIG. 6 is a drive waveform for driving the piezoelectric element, and the lower waveform in FIG. 6 is a meniscus frequency.

The waveforms of the solid lines (A) and (B) in the lower part of FIG. 6 are the meniscus frequencies of the nozzles 1 and 6 in Reference Example 1 when the length of the upper electrode 104 is constant. Regarding this, if the length of the upper electrode 104 of the nozzle 1 is reduced as in Reference Example 2, the solid line waveform (A) becomes a broken line waveform (C), and the resonance period shifts. In this state, when the drive waveform is changed, for example, in a simple extrusion waveform, the discharge speed becomes constant, but since the resonance period is deviated, the discharge speed varies due to the drive by multipath.

<< Details of this embodiment >>
Next, the details of this embodiment will be described with reference to FIGS. 7 to 10.
A plan view of the liquid discharge head of the present embodiment is shown in FIG. 7A. FIG. 7A schematically describes a plan view when viewed from a direction perpendicular to the surface of the nozzle substrate, and is the same plan view as in FIGS. 3A and 5A. Here, as in the above reference example, the main parts for explanation are shown, and the piezoelectric body 103, the upper electrode 104, the upper electrode wiring 113, and the first insulating film 106 formed on the liquid chamber substrate 100 are shown. Has been done. On the other hand, the individual liquid chamber 110, the fluid resistance portion 111, and the ink flow path 201 are indicated by broken lines.

In addition, also in this embodiment, the individual liquid chamber 110 has a longitudinal direction and a short side in the surface direction of the nozzle substrate 300, and hereinafter, when simply referred to as a longitudinal direction and a short side direction, the individual liquid chambers are respectively. It means the longitudinal direction and the lateral direction of 110. Further, the piezoelectric body 103 and the upper electrode 104 of the present embodiment also have a longitudinal direction and a short side in the surface direction of the substrate, and the longitudinal direction and the lateral side of the piezoelectric body 103 and the upper electrode 104 are individual liquid chambers. It coincides with the longitudinal direction and the lateral direction of 110, respectively.

Further, when the terms "area of the upper electrode" and "area of the insulating film" are expressed, the area of the upper electrode 104 and the insulation in the portion overlapping with the individual liquid chamber 110 when viewed from the direction perpendicular to the surface of the nozzle substrate. It means the area of the film. In the present embodiment, the area of the first insulating film 106 corresponds to the "area of the insulating film".

Further, the individual liquid chamber 110, the piezoelectric body 103, and the upper electrode 104 are used as discharge units, and the discharge units are arranged in the lateral direction of the individual liquid chamber 110. In addition, there is a part where the nozzle is described as a discharge unit.

In FIG. 5A in Reference Example 2, the area (length in the longitudinal direction) of the upper electrode 104 was changed between the nozzles, but the area of the first insulating film 106 was constant between the nozzles.
On the other hand, in the present embodiment, in addition to changing the area of the upper electrode 104 between the nozzles, the area of the first insulating film 106 is also changed between the nozzles. As shown in the figure, in the nozzle 1, the upper electrode 104 is formed to have a shorter length in the longitudinal direction than the other nozzles, and the first insulating film is formed on the piezoelectric body 103 in the region where the upper electrode 104 is shortened. 106 is extended and formed.

FIG. 8 shows a cross-sectional view of the individual liquid chamber 110 in the longitudinal direction in the present embodiment. 8A (a) corresponds to a cross-sectional view of the nozzle 6 in FIG. 7A, and FIG. 8A (b) is an enlarged view of FIG. 8A (a). 8B (a) corresponds to a cross-sectional view of the nozzle 3 in FIG. 7A, FIG. 8B (b) is an enlarged view of a longitudinal cross section of the nozzle 2, and FIG. 8B (c) is an enlarged view of a longitudinal cross section of the nozzle 1. It is a figure.

As shown in the figure, the first insulating film 106 is extended in the discharge unit in which the length of the upper electrode 104 is shortened. As described above, the area of the upper electrode 104 and the area of the first insulating film 106 have a relationship that the larger one becomes smaller, and the other becomes smaller, and there is a negative correlation between the discharge units.

The rigidity of the diaphragm is relaxed by reducing the area of the upper electrode, but the rigidity of the diaphragm is returned to be rigid by increasing the area of the insulating film in this discharge unit. As a result, fluctuations in the compliance of the diaphragm can be suppressed. Therefore, it is possible to correct the variation in the discharge speed without changing the resonance period of the individual liquid chambers. Further, the exclusion volume of the actuator can be adjusted in the head without changing the resonance period of the individual liquid chambers.

A plot of various characteristics in this embodiment is shown in FIG. 7B. Even when there is a distribution in the displacement δ as shown in FIG. 7B (a), by configuring as described above, as shown in FIGS. 7B (b) and 7B (c), the exclusion volume ΔW and the diaphragm Displacement of compliance can be suppressed, and it can be made uniform among nozzles.

Therefore, according to the present embodiment, since the variation in the exclusion volume ΔW is suppressed, the variation in the discharge rate can be suppressed as shown in FIG. 7B (d), and the variation in the diaphragm compliance is suppressed. be able to. As a result, the variation in the resonance period can be suppressed, good ejection characteristics can be obtained, and a high-quality image can be obtained.

In the cross-sectional view of FIG. 8, the discharge unit in which the upper electrode 104 and the first insulating film 106 formed on the piezoelectric body 103 are separated from each other is shown, but the present invention is not limited to this, and for example, a nozzle. As in 4, the upper electrode 104 and the first insulating film 106 may be in contact with each other. Further, the upper electrode 104 and the first insulating film 106 may overlap each other, and for example, there may be a portion where the first insulating film 106 is formed on the upper electrode 104.

Within the same head, a region from a location where the length of the upper electrode 104 is maximized to a location where the length is minimized in order to align the exclusion volume ΔW is referred to as an exclusion volume ΔW and a compliance adjustment region. In this embodiment, it is shown as reference numeral (A) in FIG. 7A. The length of the first insulating film 106 is adjusted in this adjustment region, and the exclusion volume ΔW and compliance are adjusted at the same time.

Here, a specific example of the upper electrode 104 and the first insulating film 106 of the present embodiment is shown in FIG. FIG. 9 is a plot of the lengths of the upper electrode 104 and the first insulating film 106 in the longitudinal direction in the adjustment region, and the nozzle numbers in FIG. 9 correspond to the nozzle numbers in FIG. 7A.

In this example, Pt having a thickness of 0.125 μm is used as the upper electrode 104, and SiO ₂ having a thickness of 0.8 μm is used as the first insulating film 106. As shown in the figure, the fluctuation of the area (length in this case) of the upper electrode 104 and the area (length) of the first insulating film 106 has a negative correlation, and such a length distribution is used. The compliance of the diaphragm can be made constant between the discharge units. As a result, it is possible to suppress variations in discharge characteristics without changing the resonance period.

The method of taking the adjustment area is not particularly limited and can be changed as appropriate. In the present embodiment, it is set to 100 μm in the lateral direction, but the present invention is not limited to this, and it can be changed as appropriate.

The material of the first insulating film 106 can be changed as appropriate, and _{examples thereof include SiO 2} , SiN, and the like.
The thickness of the first insulating film 106 is not particularly limited and can be appropriately changed.

In the present embodiment, an example in which the first insulating film 106 is used as the insulating film having a negative correlation with the area of the upper electrode 104 is shown, but the present invention is not limited to this, and may be changed as appropriate. It is possible. As will be described later, the area of the second insulating film 107 may have a negative correlation with the area of the upper electrode 104, or the areas of the first insulating film 106 and the second insulating film 107 may be the area of the upper electrode. May have a negative correlation with.

Further, in the present embodiment, the area of the upper electrode 104 at the lateral end of the individual liquid chamber 110 is the smallest when viewed from the direction perpendicular to the surface of the nozzle substrate 300. Therefore, the area of the first insulating film 106 is the largest in the discharge unit at the end in the lateral direction.

The present invention is not limited to this. For example, as shown in FIG. 4 (b), when the discharge speed varies for each actuator wafer, the head corresponding to A in the figure does not have the discharge speed distribution as shown in FIG. 4 (a), and the discharge speed distribution does not occur. Will have an inclination.

In this case, it is preferable to maximize the area of the upper electrode in the nozzle 1 at the end and continuously increase the area of the upper electrode toward the nozzle 320 at the other end. Then, the area of the insulating film in the nozzle 1 is minimized, and the area of the insulating film is continuously reduced toward the nozzle 320. As a result, the diaphragm compliance can be made uniform and the variation in the resonance period can be suppressed. Therefore, it is possible to make adjustments in the head without separately providing a device for suppressing variations between wafers.

Also, in the heads and the like corresponding to B, C, and D in FIG. 4B, the area of the upper electrode and the area of the insulating film have a negative correlation, and resonance is achieved by adjusting the diaphragm compliance to be uniform. It is possible to suppress the variation of the cycle and make the discharge speed uniform.

In the present embodiment, the area of the upper electrode 104 has a negative correlation with the area of the first insulating film 106 because the length of the individual liquid chamber 110 in the longitudinal direction differs between the discharge units. By adjusting the length of the upper electrode 104 in the longitudinal direction in this way, the drive area can be adjusted with high resolution.

Further, in the present embodiment, the first insulating film 106 has a negative correlation with the area of the upper electrode 104 because the length of the individual liquid chamber 110 in the longitudinal direction differs between the discharge units. By adjusting the length of the first insulating film 106 in the longitudinal direction in this way, the resonance period of the individual liquid chambers can be adjusted without affecting the driving unit.

In the present embodiment, the area of the upper electrode 104 and the area of the first insulating film 106 are different in all of the nozzles 1 to 6, but the present invention is not limited to this.
In the present invention, there is at least one in which the area of the upper electrode 104 and the area of the insulating film in the portion overlapping the individual liquid chamber 110 differ between the discharge units when viewed from the direction perpendicular to the surface of the nozzle substrate 300. You just have to do it. Therefore, the number of different discharge units can be changed as appropriate.

Further, in the present embodiment, the upper electrode 104 has a negative correlation with the area of the insulating film because the length differs between the discharge units on one side in the longitudinal direction of the individual liquid chamber 110. As shown in FIG. 7A, the longitudinal length of the upper electrode 104 is adjusted on the side opposite to the upper electrode contact hole 123. That is, the illustrated adjustment region is located on the opposite side of the upper electrode contact hole 123. In this case, the electrode area can be easily adjusted.

<Second embodiment>
Next, other embodiments according to the present invention will be described. Descriptions of matters common to the above embodiments will be omitted.
In the present embodiment, assuming that a plurality of adjacent discharge units are a discharge unit group, the area of the upper electrode 104 and the insulating film in the portion overlapping the individual liquid chamber 110 when viewed from the direction perpendicular to the surface of the nozzle substrate 300. The area is the same within the discharge unit group, there is at least one difference between the discharge unit groups, and there is a negative correlation between the discharge unit groups.

The liquid discharge head according to the present embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is a diagram showing the distribution of the discharge speed between the nozzles. For example, when the number of nozzles of the liquid discharge head is 1 to 320, the discharge unit groups of the nozzles 1 to 20, the nozzles 21 to 300, and the nozzles 301 to 320 are group A, group C, and group B, respectively. Group A and group B are located on the end side of the head, and group C is located on the center side. Within the A group, the B group, and the C group, the discharge characteristics (discharge speed) between the discharge units are substantially uniform. As shown in FIG. 10, the discharge speeds of the A group and the B group are almost the same, and the discharge speed is higher than that of the C group. Therefore, the discharge speed varies in the head, and the same problem as in the reference example occurs.

A plan view of the liquid discharge head according to the present embodiment is shown in FIG. FIG. 11A is a plan view of groups A and B, and FIG. 11B is a plan view of group C. As shown in the figure, in the groups A, B, and C, the area of the upper electrode 104 is constant among the discharge units, and the area of the first insulating film 106 is constant. As shown in FIG. 11A, the area of the upper electrode 104 is the same in the group A and the group B, and the area of the first insulating film 106 is the same. On the other hand, when the area A (or group B) and the group C are compared, the area of the upper electrode 104 and the area of the first insulating film 106 are different.

In the example of this embodiment, the upper electrode 104 in the group A (group B) is formed shorter in the longitudinal direction than the upper electrode 104 in the group C, and the first insulating film 106 in the group A (group B) is the group C. It is formed longer in the longitudinal direction than the first insulating film 106 in the above.

In this way, the area of the upper electrode 104 and the area of the first insulating film 106 may have a negative correlation between the discharge unit groups. As a result, the discharge characteristics and the resonance period can be made uniform among the discharge unit groups of the A group, the B group, and the C group, and a liquid discharge head capable of obtaining a high quality image can be obtained.

In the present embodiment, there is one different discharge unit group, but the present invention is not limited to this, and there may be a plurality of different discharge unit groups.

As in the above embodiment, the insulating film having a negative correlation with the area of the upper electrode 104 is not limited to the first insulating film 106, but may be the second insulating film 107 or the first insulating film. The film 106 and the second insulating film 107 may be used.

<Third embodiment>
Next, other embodiments according to the present invention will be described. Descriptions of matters common to the above embodiments will be omitted. In the present embodiment, the insulating film having a negative correlation with the area of the upper electrode 104 is the second insulating film 107. The basic configuration is the same as that of the first embodiment, except that the insulating film having a negative correlation with the upper electrode 104 is the second insulating film 107 instead of the first insulating film 106.

FIG. 12 shows a cross-sectional view of the liquid discharge head according to the present embodiment in the longitudinal direction. Note that FIG. 12 is a cross-sectional view similar to that of FIG. 8B.
As shown in the figure, in the present embodiment, the second insulating film 107 is extended on the piezoelectric body 103, and the second insulating film 107 has a negative correlation with the area of the upper electrode 104 between the ejection units. ing.

Here, a specific example of the upper electrode 104 and the second insulating film 107 of the present embodiment is shown in FIG. FIG. 13 is a plot of the lengths of the upper electrode 104 and the second insulating film 107 in the longitudinal direction in the adjustment region as in FIG. 9, and the nozzle numbers in FIG. 13 correspond to the nozzle numbers in FIG. 7A.

In this example, Pt having a thickness of 0.125 μm is used as the upper electrode 104, and SiN having a thickness of 0.2 μm is used as the second insulating film 107. As shown in the figure, the fluctuation of the area (length in this case) of the upper electrode 104 and the area (length) of the second insulating film 107 has a negative correlation, and vibration is caused by such a length distribution. The plate compliance is kept constant between discharge units. As a result, variations in discharge characteristics can be suppressed.

The material of the second insulating film 107 can be changed as appropriate, and _{examples thereof include SiO 2} , SiN, and the like.
The thickness of the second insulating film 107 is not particularly limited and can be appropriately changed.

Since the liquid discharge head basically has the second insulating film 107, the second insulating film 107 can be manufactured by an etching process in a normal semiconductor process without adding another manufacturing process. Therefore, when adjusting the second insulating film 107 as in the present embodiment, it is only necessary to change the mask drawing, so that additional cost can be suppressed.

<Fourth Embodiment>
Next, other embodiments according to the present invention will be described. Descriptions of matters common to the above embodiments will be omitted.
In the present embodiment, the insulating film having a negative correlation with the area of the upper electrode 104 is composed of a plurality of films. By forming the insulating film into a plurality of layers, it becomes easier to adjust the resonance period of the individual liquid chamber 110, so that the degree of freedom in designing the film thickness and rigidity of each layer can be improved, and the discharge rate can be more reliably increased. Can be uniform.

Further, in the present embodiment, the insulating films having a negative correlation with the area of the upper electrode 104 are preferably the first insulating film 106 and the second insulating film 107. A cross-sectional view of the liquid discharge head in the longitudinal direction in this case is shown in FIG. Note that FIG. 14 is a cross-sectional view similar to that of FIG. 8B.

As shown in the present embodiment, the first insulating film 106 and the second insulating film 107 are extended on the piezoelectric body 103, and the first insulating film 106 and the second insulating film 107 are between discharge units. It has a negative correlation with the area of the upper electrode 104.

Since the insulating films having a negative correlation with the area of the upper electrode 104 are the first insulating film 106 and the second insulating film 107, there is an advantage when the above-mentioned insulating film has a plurality of layers. Further, since the liquid discharge head basically has the first insulating film 106 and the second insulating film 107, in the case of the configuration of the present embodiment, it is only necessary to change the mask drawing, and the additional cost related to manufacturing is required. Can be suppressed.

<Fifth Embodiment>
Next, other embodiments according to the present invention will be described. Descriptions of matters common to the above embodiments will be omitted.
In the present embodiment, the insulating film has a void 148, which has a negative correlation with the area of the upper electrode 104. The liquid discharge head according to the present embodiment will be described with reference to FIG. 15A is a plan view of the liquid discharge head of the present embodiment, FIG. 15B is a sectional view in the longitudinal direction, and corresponds to a sectional view in the longitudinal direction of the nozzle 4 in FIG. 15A. As shown in the figure, a void 148 is formed in the first insulating film 106, and by adjusting the area of the void 148, it has a negative correlation with the area of the upper electrode 104.

In the example shown in FIG. 15A, in the nozzles 2 to 6, the first insulating film 106 is also formed on the upper electrode 104, but the present invention is not limited to this, and the first insulating film 106 is formed on the upper electrode 104. The film 106 may not be formed.

Further, as in the above embodiment, the insulating film having a negative correlation with the area of the upper electrode 104 is not limited to the first insulating film 106, but may be the second insulating film 107 or the first insulating film. The film 106 and the second insulating film 107 may be used.

<Sixth Embodiment>
Next, other embodiments according to the present invention will be described. Descriptions of matters common to the above embodiments will be omitted.
In the present embodiment, there is at least one discharge unit in which the insulating film is formed on the piezoelectric body 103, and in the discharge unit, the insulating film is provided at the end of the piezoelectric body 103 in the longitudinal direction of the individual liquid chamber 110. Not formed.

The liquid discharge head according to the present embodiment will be described with reference to FIG. 16A is a plan view of the liquid discharge head of the present embodiment, FIG. 16B is a sectional view in the longitudinal direction, and corresponds to a sectional view of the nozzle 2 in the longitudinal direction in FIG. 16A.
As shown, no insulating film is formed at the end of the piezoelectric body 103 in the longitudinal direction. This is shown as an insulating film non-forming portion 138 in the plan view and the cross-sectional view.

In the present embodiment, the edge of the piezoelectric body 103 in the longitudinal direction of the individual liquid chamber 110 is not coated with an insulating film, and the insulating film for compliance adjustment is separated from the insulating film covering the outside of the individual liquid chamber 110. ing. When the edge of the piezoelectric body 103 is covered, the displacement is suppressed by the fixed insulating film. However, in the present embodiment, since the edge of the piezoelectric body is not covered with the insulating film, the displacement can be prevented from being suppressed. .. This makes it possible to prevent deterioration of the discharge characteristics.

<Other Embodiments>
In the above embodiment, the area of the upper electrode and the area of the insulating film have a negative correlation by adjusting the length of the upper electrode 104 in the longitudinal direction. In the present invention, the length in the lateral direction may be adjusted to have a negative correlation with the areas of the upper electrode and the insulating film. That is, at least one of the lengths of the upper electrode 104 and the insulating film in the lateral direction differs between the discharge units, and the area of the upper electrode and the area of the insulating film have a negative correlation. In the discharge unit where the length of the upper electrode in the short direction is short, the length of the insulating film in the short direction is long, and in the discharge unit where the length of the upper electrode is long in the short direction, the short side of the insulating film is used. It has a negative correlation that the length in the direction becomes shorter. Also in this embodiment, it is possible to suppress variations in the resonance period and the discharge speed of the individual liquid chambers and obtain a high-quality image.

<One Embodiment of the manufacturing method of the liquid discharge head>
Next, an example of the method for manufacturing the liquid discharge head according to the first embodiment will be described with reference to FIGS. 17 and 18. 17 and 18 are cross-sectional views of the individual liquid chambers of the liquid discharge head in the longitudinal direction.

[Fig. 17 (a), Fig. 17 (b)]
A silicon nitride film as a mask is patterned on a portion of the liquid chamber substrate 100a other than the portion where the diaphragm 101 is provided. Further, a vibrator plate 101, which is a multilayer laminated film of _{polysilicon and SiO 2} , is formed on the liquid chamber substrate 100a by means for forming a polysilicon and silicon thermal oxide film (for example, plasma CVD method, pyrooxidation method, etc.).

[Fig. 17 (c)]
Next, by a thin film forming means (for example, a sol-gel method, a sputtering method, etc.), _{a lower electrode 102 composed of, for example, Pt, Ti, LaNiO 3} (lantern nickel acid), SrRuO ₃ (strontium ruthenium oxide), for example, PZT (lead zirconate titanate). A layer of the piezoelectric body 103 made of lead acid), for example, a layer of the upper electrode 104 made of _{Pt, LaNiO 3} , and SrRuO _{3 is sequentially formed.}

[Fig. 17 (d)]
Next, the upper electrode 104, the piezoelectric body 103, and the lower electrode 102 are sequentially patterned by a photolithography method to form the piezoelectric element 105.

In the first embodiment, the area of the upper electrode 104 and the area of the first insulating film 106 have a negative correlation, and the area of the upper electrode 104 for each nozzle is adjusted so that the diaphragm compliance is uniform among the nozzles. doing. The dimensions of the upper electrode 104 can be adjusted in the etching process of a normal semiconductor process, and when changing the dimensions of the upper electrode 104 between nozzles, it is only necessary to change the mask drawing. Therefore, the additional cost for adopting this configuration can be suppressed.

[Fig. 17 (e)]
Next, a first insulating film 106 (for example, SiO ₂ ) for forming wiring is formed in a region that does not interfere with vibration. This step is a feature of the present embodiment, and the film is formed by determining the covering area for each nozzle as described above so that the elastic compliance of the diaphragm is constant.

In the first embodiment, the area of the first insulating film 106 has a negative correlation with the area of the upper electrode 104, and the area of the first insulating film 106 for each nozzle so that the diaphragm compliance is uniform among the nozzles. Is being adjusted. Since the liquid discharge head basically has the first insulating film 106, it is not necessary to add another manufacturing process, and the first insulating film 106 can be manufactured by an etching process of a normal semiconductor process. Therefore, when adjusting the area of the first insulating film 106 as in the present embodiment, it is only necessary to change the mask drawing, so that additional cost can be suppressed.

[Fig. 17 (f)]
Next, for example, the lower electrode wiring 112 and the upper electrode wiring 113 made of aluminum are formed at desired positions.

[Fig. 17 (g)]
A second insulating film 107 made _{of, for example, SiO 2} or SiN is formed on the end of the piezoelectric element 105 and the lower electrode 102 so as not to interfere with the vibration displacement. This step is also a feature of the present embodiment as in the step of FIG. 17 (e). In this way, the liquid chamber substrate 100b is obtained.

In the third embodiment, the area of the second insulating film 107 has a negative correlation with the area of the upper electrode 104, and the second insulating film for each nozzle so that the diaphragm compliance is uniform among the nozzles. The area of 107 is adjusted. Since the liquid discharge head basically has the second insulating film 107, it is not necessary to add another manufacturing process, and the second insulating film 107 can be manufactured by the etching process of a normal semiconductor process. Therefore, when adjusting the area of the second insulating film 107 as in the third embodiment, it is only necessary to change the mask drawing, and the additional cost can be suppressed.

[Fig. 18 (a)]
Separately, the holding substrate 200 used in the following procedure is produced. A recess, an ink flow path 201, and an arrangement region of the drive IC 160, which are drive regions of the piezoelectric element 105, are formed on the silicon substrate by the litho-etch method.

[Fig. 18 (b)]
An adhesive is applied to the holding substrate 200 and joined to the surface of the liquid chamber substrate 100b on which the piezoelectric element 105 is formed.

[Fig. 18 (c)]
The surface of the liquid chamber substrate 100b opposite to the surface on which the piezoelectric element 105 is formed is polished to a desired thickness.

[Fig. 18 (d)]
The surface of the liquid chamber substrate 100b opposite to the surface on which the piezoelectric element 105 is formed is etched by ICP dry etching to form the individual liquid chamber 110, the fluid resistance portion 111, and the ink flow path 201.

[Fig. 18 (e)]
A diaphragm filter 115 is formed on the diaphragm 101 of the liquid chamber substrate 100b by ICP dry etching.

[Fig. 18 (f)]
A separately manufactured drive IC 160 is mounted on the electrode pad 133 provided on the joint surface side with the holding substrate 200 in the liquid chamber substrate 100b by flip-chip bonding, and the sealing material 161 is poured into the liquid chamber substrate 100b for insulation.
Further, by dicing, the liquid chamber substrate 100 is changed from the wafer shape to a desired individualized shape.

[Fig. 18 (g)]
Separately, the nozzle substrate 300 on which the nozzle 301 is formed by press working and polishing of SUS is joined.

The liquid discharge head of the present embodiment can be manufactured by the steps described above.

(Liquid discharge unit, device that discharges liquid)
Next, an example of the device for discharging the liquid according to the present invention will be described with reference to FIGS. 19 and 20. FIG. 19 is an explanatory plan view of a main part of the device, and FIG. 20 is an explanatory side view of the main part of the device.

This device is a serial type device, and the carriage 403 is reciprocated in the main scanning direction by the main scanning moving mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 is bridged over the left and right side plates 491A and 491B to movably hold the carriage 403. Then, the carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 bridged between the drive pulley 406 and the driven pulley 407.

The carriage 403 is equipped with a liquid discharge unit 440 in which the liquid discharge head 404 and the head tank 441 according to the present invention are integrated. The liquid discharge head 404 of the liquid discharge unit 440 discharges liquids of, for example, yellow (Y), cyan (C), magenta (M), and black (K). Further, the liquid discharge head 404 is mounted by arranging a nozzle array composed of a plurality of nozzles in the sub-scanning direction orthogonal to the main scanning direction and directing the discharge direction downward.

The liquid stored in the liquid cartridge 450 is supplied to the head tank 441 by the supply mechanism 494 for supplying the liquid stored outside the liquid discharge head 404 to the liquid discharge head 404.

The supply mechanism 494 includes a cartridge holder 451 which is a filling portion for mounting the liquid cartridge 450, a tube 456, a liquid feeding unit 452 including a liquid feeding pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. Liquid is sent from the liquid cartridge 450 to the head tank 441 by the liquid feeding unit 452 via the tube 456.

This device includes a transport mechanism 495 for transporting the paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412.

The transport belt 412 attracts the paper 410 and transports it at a position facing the liquid discharge head 404. The transport belt 412 is an endless belt, and is hung between the transport roller 413 and the tension roller 414. Adsorption can be performed by electrostatic adsorption, air suction, or the like.

Then, the transport belt 412 orbits in the sub-scanning direction by rotationally driving the transport roller 413 via the timing belt 417 and the timing pulley 418 by the sub-scanning motor 416.

Further, on one side of the carriage 403 in the main scanning direction, a maintenance / recovery mechanism 420 for maintaining / recovering the liquid discharge head 404 is arranged on the side of the transport belt 412.

The maintenance / recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzle is formed) of the liquid discharge head 404, a wiper member 422 that wipes the nozzle surface, and the like.

The main scanning movement mechanism 493, the supply mechanism 494, the maintenance / recovery mechanism 420, and the transport mechanism 495 are attached to a housing including the side plates 491A and 491B and the back plate 491C.

In this device configured in this way, the paper 410 is fed onto the transport belt 412 and sucked, and the paper 410 is transported in the sub-scanning direction by the orbital movement of the transport belt 412.

Therefore, by driving the liquid discharge head 404 in response to the image signal while moving the carriage 403 in the main scanning direction, the liquid is discharged to the stopped paper 410 to form an image.

As described above, since this device includes the liquid discharge head according to the present invention, it is possible to stably form a high-quality image.

Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 21 is an explanatory plan view of a main part of the unit.

This liquid discharge unit includes a housing portion composed of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid among the members constituting the device for discharging the liquid. It is composed of a discharge head 404.

A liquid discharge unit may be configured in which at least one of the above-mentioned maintenance / recovery mechanism 420 and the supply mechanism 494 is further attached to, for example, the side plate 491B of the liquid discharge unit.

Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 22 is a front explanatory view of the unit.

This liquid discharge unit includes a liquid discharge head 404 to which the flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

The flow path component 444 is arranged inside the cover 442. A head tank 441 may be included instead of the flow path component 444. Further, a connector 443 that electrically connects to the liquid discharge head 404 is provided on the upper part of the flow path component 444.

In the present application, the "device for discharging a liquid" is a device provided with a liquid discharge head or a liquid discharge unit and driving the liquid discharge head to discharge the liquid. The device for discharging the liquid includes not only a device capable of discharging the liquid to a device to which the liquid can adhere, but also a device for discharging the liquid toward the air or the liquid.

The "device for discharging the liquid" can also include means for feeding, transporting, and discharging paper to which the liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "device that ejects a liquid", an image forming apparatus that ejects ink to form an image on paper, and a three-dimensional object (three-dimensional object) are formed in layers in order to form a three-dimensional object. There is a three-dimensional modeling device (three-dimensional modeling device) that discharges the modeling liquid into the powder layer.

Further, the "device for discharging a liquid" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves and those that form a three-dimensional image are also included.

The above-mentioned "material to which a liquid can adhere" means a material to which a liquid can adhere at least temporarily, such as one that adheres and adheres, and one that adheres and permeates. Specific examples include paper, recording paper, recording paper, film, recording media such as cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and media such as inspection cells. Yes, including anything to which the liquid adheres, unless otherwise specified.

The above "materials to which liquid can adhere" are temporary liquids such as paper, threads, fibers, fabrics, leather, metals, plastics, glass, wood, ceramics, building materials such as wallpaper and flooring, and textiles for clothing. However, it is sufficient if it can be attached.

The "liquid" also includes inks, treatment liquids, DNA samples, resists, pattern materials, binders, modeling liquids, or solutions and dispersions containing amino acids, proteins, and calcium.

Further, the "device for discharging the liquid" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In addition, as a "device for ejecting liquid", a treatment liquid coating device for ejecting a treatment liquid to the paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, raw materials. There is an injection granulator that granulates fine particles of raw materials by injecting a composition liquid in which the above-mentioned material is dispersed in a solution through a nozzle.

The "liquid discharge unit" is a liquid discharge head integrated with functional parts and a mechanism, and is an assembly of parts related to liquid discharge. For example, the "liquid discharge unit" includes a combination of at least one of a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, and a main scanning movement mechanism with a liquid discharge head.

Here, "integration" means, for example, a liquid discharge head and a functional component, a mechanism in which the mechanism is fixed to each other by fastening, adhesion, engagement, etc., or one in which one is movably held with respect to the other. include. Further, the liquid discharge head, the functional parts, and the mechanism may be detachably attached to each other.

For example, as a liquid discharge unit, there is a liquid discharge head and a head tank integrated, such as the liquid discharge unit 440 shown in FIG. Further, there is a case in which the liquid discharge head and the head tank are integrated by being connected to each other by a tube or the like. Here, a unit including a filter can be added between the head tank of these liquid discharge units and the liquid discharge head.

Further, as a liquid discharge unit, there is a liquid discharge head and a carriage integrated.

Further, as a liquid discharge unit, there is a liquid discharge head in which the liquid discharge head and the scanning movement mechanism are integrated by holding the liquid discharge head movably by a guide member forming a part of the scanning movement mechanism. Further, as shown in FIG. 21, there is a liquid discharge unit in which a liquid discharge head, a carriage, and a main scanning movement mechanism are integrated.

Further, as a liquid discharge unit, there is a carriage to which a liquid discharge head is attached, in which a cap member which is a part of the maintenance / recovery mechanism is fixed, and the liquid discharge head, the carriage, and the maintenance / recovery mechanism are integrated. ..

Further, as a liquid discharge unit, as shown in FIG. 22, a tube is connected to a liquid discharge head to which a head tank or a flow path component is attached, and the liquid discharge head and a supply mechanism are integrated. ..

The main scanning movement mechanism shall also include a single guide member. Further, the supply mechanism includes a single tube and a single loading unit.

Further, the pressure generating means used for the "liquid discharge head" is not limited. For example, in addition to the piezoelectric actuator (which may use a laminated piezoelectric element) as described in the above embodiment, it is composed of a thermal actuator using an electric heat conversion element such as a heat generating resistor, a vibrating plate, and a counter electrode. An electrostatic actuator or the like may be used.

In addition, image formation, recording, printing, printing, printing, modeling, etc. in the terms of the present application are all synonymous.

100 Liquid chamber substrate 101 Vibrating plate 102 Lower electrode 103 piezoelectric body 104 Upper electrode 105 piezoelectric element 106 First insulating film 107 Second insulating film 108 Holding substrate partition 109 Liquid chamber partition 110 Individual liquid chamber 111 Fluid resistance part 112 Lower electrode wiring 113 Upper electrode wiring 120 Common liquid chamber 122 Lower electrode contact hole 123 Upper electrode contact hole 130 Insulating film 133 Electrode pad 138 Insulating film non-forming part 148 Void 160 Drive IC
161 Encapsulant 170 Actuator Wafer 200 Holding board 201 Ink flow path 300 Nozzle board 301 Nozzle 401 Guide member 403 Carriage 404 Liquid discharge head 405 Main scanning motor 406 Drive pulley 407 Driven pulley 408 Timing belt 410 Paper 412 Conveyance belt 413 Conveyor roller 414 Tension roller 416 Sub-scanning motor 417 Timing belt 418 Timing pulley 420 Maintenance / recovery mechanism 421 Cap member 422 Wiper member 440 Liquid discharge unit 441 Head tank 442 Cover 443 Connector 444 Flow path parts 450 Liquid cartridge 451 Cartridge holder 452 Liquid transfer unit 451 A , 491B Side plate 491C Back plate 493 Main scanning movement mechanism 494 Supply mechanism 495 Transport mechanism

Japanese Unexamined Patent Publication No. 2006-224609 Japanese Patent No. 5194309 Japanese Unexamined Patent Publication No. 2008-221766

Claims (15)

A nozzle board with multiple nozzles and
An individual liquid chamber that communicates with the nozzle and has a length and a short side in the surface direction of the nozzle substrate.
A diaphragm forming at least a part of the individual liquid chamber and
A lower electrode formed on the diaphragm, a piezoelectric element formed on the lower electrode, and a piezoelectric element having an upper electrode formed on the piezoelectric body.
It has an insulating film formed on the diaphragm and
Assuming that the individual liquid chamber, the piezoelectric body, and the upper electrode are discharge units, the discharge units are arranged in the lateral direction of the individual liquid chamber.
When viewed from a direction perpendicular to the surface of the nozzle substrate, there is at least one in which the area of the upper electrode and the area of the insulating film in the portion overlapping the individual liquid chambers differ between the discharge units. , A liquid discharge head characterized by having a negative correlation between the discharge units. The liquid discharge head according to claim 1, wherein the liquid discharge head has a negative correlation between the discharge units so that the compliance of the diaphragm is aligned between the discharge units. When a plurality of adjacent discharge units are designated as a discharge unit group, the area of the upper electrode and the area of the insulating film in the portion overlapping the individual liquid chambers when viewed from a direction perpendicular to the surface of the nozzle substrate Claim 1 or 2 is characterized in that each of them is the same in the discharge unit group, there is at least one different among the discharge unit groups, and there is a negative correlation between the discharge unit groups. The liquid discharge head described in. The invention according to any one of claims 1 to 3, wherein the area of the upper electrode at the lateral end of the individual liquid chamber is the smallest when viewed from a direction perpendicular to the surface of the nozzle substrate. Liquid discharge head. A wiring layer that conducts with the piezoelectric element,
It has a first insulating film formed between the wiring layer and the piezoelectric element.
The liquid discharge head according to any one of claims 1 to 4, wherein the insulating film having a negative correlation with the area of the upper electrode is the first insulating film. A wiring layer that conducts with the piezoelectric element,
It has a second insulating film formed on the wiring layer, and has.
The liquid discharge head according to any one of claims 1 to 4, wherein the insulating film having a negative correlation with the area of the upper electrode is the second insulating film. A wiring layer that conducts with the piezoelectric element,
A first insulating film formed between the wiring layer and the piezoelectric element,
It has a second insulating film formed on the wiring layer, and has.
The liquid discharge head according to any one of claims 1 to 4, wherein the insulating film having a negative correlation with the area of the upper electrode is the first insulating film and the second insulating film. The upper electrode according to any one of claims 1 to 7, wherein the upper electrode has a negative correlation with the area of the insulating film because the length of the individual liquid chamber in the longitudinal direction differs between the discharge units. The liquid discharge head described. The insulating film has a negative correlation with the area of the upper electrode because the length of the individual liquid chambers in the longitudinal direction differs between the discharge units, according to any one of claims 1 to 8. The liquid discharge head described. The liquid discharge head according to any one of claims 1 to 9, wherein the insulating film has a negative correlation with the area of the upper electrode by having a gap. Claims 1 to 10 are characterized in that the upper electrode has a negative correlation with the area of the insulating film because the length differs between the discharge units on one side in the longitudinal direction of the individual liquid chamber. The liquid discharge head according to any one of. There is at least one discharge unit in which the insulating film is formed on the piezoelectric body, and in the discharge unit, the insulating film is formed at the end of the piezoelectric body in the longitudinal direction of the individual liquid chamber. The liquid discharge head according to any one of claims 1 to 11, wherein the liquid discharge head is not provided. A liquid discharge unit comprising the liquid discharge head according to any one of claims 1 to 12. A head tank that stores the liquid to be supplied to the liquid discharge head, a carriage on which the liquid discharge head is mounted, a supply mechanism that supplies the liquid to the liquid discharge head, a maintenance / recovery mechanism that maintains and recovers the liquid discharge head, and the liquid. The liquid discharge unit according to claim 13, wherein at least one of the main scanning moving mechanisms for moving the discharge head in the main scanning direction is integrated with the liquid discharge head. A device for discharging a liquid, which comprises the liquid discharge head according to any one of claims 1 to 12 or the liquid discharge unit according to claim 13 or 14.

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