JP2011073356A - Liquid jetting head, liquid jetting apparatus, and method for manufacturing liquid jetting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jetting head and a liquid jetting apparatus confirmed to have desired liquid jetting characteristics with little dispersion, and a manufacturing method that can easily inspect with high accuracy whether to have desired liquid ejecting characteristics with little dispersion in a manufacturing process. <P>SOLUTION: The liquid jetting head includes a pressure generating chamber 12 communicating with each of a plurality of nozzle openings 21 for jetting liquid; a plurality of piezoelectric elements 300 causing a pressure change to each pressure generating chamber; and a pair of inspecting piezoelectric elements provided on both outer sides in a juxtaposed direction of piezoelectric elements of a piezoelectric element group including the plurality of piezoelectric elements. A piezoelectric layer of the inspecting piezoelectric element has a variation width of its saturation polarization being 5% or less, a variation width of remanence being 15% or less and a variation width of coercive electric field strength being 15% or less. The liquid jetting apparatus includes the liquid jetting head. The method for manufacturing the liquid jetting head includes a measuring process for measuring piezoelectric characteristics using the inspecting piezoelectric elements 300A. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head, a liquid ejecting apparatus, and a method for manufacturing a liquid ejecting head.

  As an ink jet recording head which is a liquid ejecting head, a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets is constituted by a vibration plate, and the vibration plate is deformed by a piezoelectric element so that ink in the pressure generating chamber is formed. There is one that uses an actuator device in a flexural vibration mode of a piezoelectric element that pressurizes and ejects ink droplets from a nozzle opening.

  As an index indicating the image quality unevenness of the printed matter of such an ink jet recording head, there is a line width inclination. Here, the line width inclination indicates a variation in line width when a single straight line is drawn. The larger the line width inclination, the larger the line width variation and the lower the print quality. In particular, when the line width inclination exceeds 6%, the visibility decreases with the naked eye. As a cause of reducing such a line width inclination, there are variations in ink droplet speed and ink droplet weight.

  Conventionally, by measuring the natural vibration period of ink, it is determined whether each ink jet recording head has a natural vibration period as designed, and by estimating the ink droplet speed and ink droplet weight, Image quality variation for each ink jet recording head is suppressed by applying feedback to the process (see, for example, Patent Document 1).

JP 2002-154212 A (Claim 1 etc.)

  However, since the natural vibration period measurement is performed on a completed inkjet recording head, there is a problem that the cost increases when a defective product occurs, and feedback to the manufacturing process is delayed. is there.

  In view of such circumstances, the present invention is a liquid ejecting head and a liquid ejecting apparatus that have been confirmed to have a desired liquid ejecting characteristic with little variation, and whether or not the liquid ejecting characteristic has a desired small variation in a manufacturing process. It is an object of the present invention to provide a manufacturing method capable of simply and highly accurately inspecting the above.

  The liquid ejecting head of the present invention includes a plurality of pressure generating chambers that communicate with a plurality of nozzle openings for ejecting liquid, a plurality of piezoelectric elements that cause a pressure change in the pressure generating chambers, A pair of inspection piezoelectric elements provided on both outer sides of the piezoelectric elements in the direction in which the piezoelectric elements are arranged, and the piezoelectric layer of the pair of inspection piezoelectric elements has a saturation polarization. The fluctuation range is within 5%, the fluctuation range of remanent polarization is within 15%, and the fluctuation range of coercive electric field strength is within 15%. In the liquid jet head according to the aspect of the invention, with the piezoelectric layer of one of the piezoelectric elements as a reference, the piezoelectric layer of the other piezoelectric element has a fluctuation range of saturation polarization within 5%, and the fluctuation range of residual polarization. Is within 15%, and the fluctuation range of the coercive electric field strength is within 15%, so that a plurality of piezoelectric element lines for discharging liquid from the pressure generating chambers disposed between the inspection piezoelectric elements on both sides Since the width inclination is within 6%, it is possible to have liquid ejection characteristics with little desired variation. Note that these saturation polarization, remanent polarization, and coercive electric field are defined in detail in FIG. 8 showing the hysteresis characteristics of the piezoelectric element.

Specifically, the piezoelectric layer of the pair of inspection piezoelectric elements has a saturation polarization difference of 1.2 μC / cm ^{2 or} less, a residual polarization difference of 2.5 μC / cm ^{2 or} less, and The difference in coercive electric field strength is preferably within 7.69 kV / cm. The fluctuation width, that is, the difference between the characteristics of the inspection piezoelectric element is derived. If this difference is within the above range, the fluctuation width is within the above range, and the line width inclination is within 6%. Can have a desired liquid ejection characteristic with little variation.

  A liquid ejecting apparatus according to an aspect of the invention includes any one of the liquid ejecting heads described above. By including the liquid ejecting head having the liquid ejecting characteristic with less variation, the liquid ejecting apparatus of the present invention has the liquid ejecting characteristic with less variation.

  The method of manufacturing a liquid ejecting head according to the present invention includes a flow path forming substrate in which a liquid flow path including a plurality of pressure generation chambers communicating with a nozzle for ejecting liquid droplets is formed, and a first surface side of the flow path forming substrate. A piezoelectric element provided to cause a pressure change in each of the pressure generating chambers, and a pair of inspection piezoelectric elements provided on both outer sides of the piezoelectric elements of the piezoelectric element group composed of a plurality of piezoelectric elements. A method of manufacturing a liquid jet head, comprising: laminating a first electrode, a piezoelectric layer, and a second electrode on one side of a flow path forming substrate in which a pressure generation chamber communicating with a nozzle opening for jetting liquid is formed A plurality of piezoelectric elements are formed by forming and patterning, and the first electrode, the piezoelectric layer, and the second electrode are respectively disposed on both outer sides of the piezoelectric elements in the parallel arrangement direction of the piezoelectric element group including the plurality of piezoelectric elements. A pair of the above-mentioned inspection pressures composed of A step of forming an element, and measuring a piezoelectric characteristic of the pair of inspection piezoelectric elements; and, from the piezoelectric characteristic, a variation range of saturation polarization, residual polarization, and coercive electric field strength of the inspection piezoelectric element. A determination step of calculating and determining whether the variation width of the saturation polarization is within 5%, the variation width of the remanent polarization is within 15%, and the variation width of the coercive electric field strength is within 15%; It is provided with. By providing a piezoelectric element for inspection and deriving and determining the fluctuation range from this piezoelectric element, it is possible to inspect the variation in piezoelectric characteristics more easily and with high accuracy, and the liquid ejection characteristics with less desired variations A liquid ejecting head having the following can be manufactured.

In the determination step, the saturation polarization difference is within 1.2 μC / cm ² , the residual polarization difference is within 2.5 μC / cm ² , and the coercive field strength difference is 7.69 kV / It is preferable to determine whether it is within cm. By deriving a difference as the fluctuation range and making a determination based on this difference, it is possible to more easily determine whether or not the liquid ejection characteristics have a small desired variation.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment of the invention. 2A and 2B are a plan view and a cross-sectional view of the recording head according to Embodiment 1 of the invention. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. 3 is a graph showing a hysteresis curve that is a measurement result according to the first embodiment. FIG. 4 is a diagram illustrating an example of a drive waveform according to the first embodiment. It is a graph which shows the result of the Example of this invention. It is a graph which shows the result of the Example of this invention. It is a graph which shows the result of the Example of this invention. It is a graph which shows the result of the Example of this invention. 1 is a perspective view illustrating a schematic configuration of a recording apparatus according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. FIG.

  As shown in the drawing, the flow path forming substrate 10 is made of a silicon single crystal substrate, and an elastic film 50 made of silicon dioxide is formed on one surface thereof.

  In the flow path forming substrate 10, a plurality of pressure generating chambers 12 are partitioned by a partition wall 11 and arranged in parallel in the width direction. In addition, a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a supply path 14 and a communication path 15. The communication part 13 communicates with a reservoir part 31 of a protective substrate, which will be described later, and constitutes a part of a reservoir that becomes a common ink chamber of each pressure generating chamber 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13.

  Further, on the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. Or a heat-welded film or the like. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, or stainless steel.

  On the other hand, the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above, and the insulator film 55 is formed on the elastic film 50. As the insulator film 55, zirconium oxide is used in this embodiment. Further, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated on the insulator film 55 by a process described later to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In the present embodiment, the first electrode 60 is a common electrode of the piezoelectric element 300, and the second electrode 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. Here, the piezoelectric element 300 that is displaced by driving is referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, and the first electrode 60 function as a diaphragm. However, the present invention is not limited to this. For example, the elastic film 50 and the insulator film 55 are provided. Instead, only the first electrode 60 may act as a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

The piezoelectric layer 70 is formed on the first electrode 60 and is made of a piezoelectric material that exhibits an electromechanical conversion action. The piezoelectric layer 70 is formed by laminating piezoelectric films that are crystal films having a perovskite structure, and includes at least Pb, Ti, and Zr. As a material of the piezoelectric layer 70, for example, a piezoelectric material (ferroelectric material) such as lead zirconate titanate (PZT) or a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide is added thereto. Are suitable, such as lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O ₃ ) or lead magnesium titanate zirconate (Pb (Zr, Ti) (Mg, Nb) O ₃ ). ) Etc. can also be used. In this embodiment, the piezoelectric layer 70 uses lead zirconate titanate and is preferentially oriented in the (100) plane. The piezoelectric layer 70 is formed to a thickness (0.5 to 5 μm) that suppresses the thickness to such an extent that cracks do not occur in the manufacturing process and exhibits sufficient displacement characteristics (0.5 to 5 μm).

  Further, as shown in FIGS. 2A and 3, the first electrode 60 is disposed on both outer sides of each row in which the piezoelectric elements 300 are juxtaposed (outside in the juxtaposition direction of the juxtaposed piezoelectric elements 300). In addition, inspection piezoelectric elements 300 </ b> A and 300 </ b> B including the piezoelectric layer 70 and the second electrode 80 are provided.

  The inspection piezoelectric elements 300 </ b> A and 300 </ b> B are used when measuring the piezoelectric characteristics (hysteresis characteristics) of the piezoelectric element 300 in the inspection process, and will be formed at the same time as the piezoelectric element 300 is formed. Is done. Since the inspection piezoelectric elements 300A and 300B are formed with the same film configuration and manufacturing conditions as the piezoelectric element 300, when the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B are measured, the piezoelectric characteristics substantially equivalent to the piezoelectric element 300 are obtained. It can be said that it has. Here, there is a difference in piezoelectric characteristics between the piezoelectric element 300 closest to the inspection piezoelectric element 300A and the piezoelectric element 300 closest to the inspection piezoelectric element 300B due to minute configuration variations such as film thickness caused by manufacturing. Arise. However, the inclination of the piezoelectric characteristics between the piezoelectric element 300 closest to the inspection piezoelectric element 300A and the piezoelectric element 300 closest to the inspection piezoelectric element 300B is smaller than the inclination of the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B. If it can be confirmed that the inclination of the piezoelectric characteristic between the inspection piezoelectric elements 300A and 300B is within a predetermined range, the piezoelectric element 300 can be said to have the inclination of the piezoelectric characteristic within the predetermined range, and the head can be used as a product. It can be judged that. In this embodiment, the piezoelectric characteristics of these inspection piezoelectric elements 300A and 300B are measured, and the fluctuation range is derived by obtaining the inclination of the piezoelectric characteristics of the piezoelectric element 300 in the liquid jet head by deriving these fluctuation ranges. If it exceeds the predetermined value, it is determined that there is variation, and if the fluctuation range does not exceed the predetermined value, it is determined that there is no variation. That is, the piezoelectric elements 300A and 300B for inspection are provided at both ends, because the piezoelectric element 300 may have an inclination (variation) in the piezoelectric characteristics in the juxtaposed direction. Inspection piezoelectric elements 300A and 300B are provided at both ends that become larger, and by examining the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B, variations of the plurality of piezoelectric elements 300 can be obtained.

The piezoelectric characteristics of the piezoelectric element 300 of the present embodiment obtained from the measurement results of the inspection piezoelectric elements 300A and 300B are the fluctuations of the piezoelectric characteristics of the inspection piezoelectric elements on one end side and the other end side in the parallel arrangement direction of the piezoelectric elements 300. The width, that is, the fluctuation width of the saturation polarization is 5% or less, the fluctuation width of the remanent polarization is 15% or less, and the fluctuation width of the coercive electric field strength is 15% or less. In order to enter such a range, for example, the saturation polarization difference between the inspection piezoelectric element 300A and the inspection piezoelectric element 300B is 1.2 μC / cm ² or less, and the residual polarization difference is 2.5 μC / cm 2. ² or less, and the difference in coercive electric field strength is 7.69 kV / cm or less.

  Further, each second electrode 80 which is an individual electrode of the piezoelectric element 300 is drawn from the vicinity of the end on the ink supply path 14 side and extended to the insulator film 55, for example, gold (Au) or the like. The lead electrode 90 which consists of is connected.

  On the flow path forming substrate 10 on which the piezoelectric element 300 is formed, that is, on the first electrode 60, the elastic film 50, and the lead electrode 90, the protection having the reservoir portion 31 constituting at least a part of the reservoir 100. The substrate 30 is bonded via an adhesive 35. In the present embodiment, the reservoir portion 31 is formed across the protective substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and as described above, the communication portion 13 of the flow path forming substrate 10 is formed. The reservoir 100 is configured as a common ink chamber for the pressure generating chambers 12. Alternatively, the communication portion 13 of the flow path forming substrate 10 may be divided into a plurality of pressure generation chambers 12 and only the reservoir portion 31 may be used as the reservoir. Further, for example, only the pressure generating chamber 12 is provided in the flow path forming substrate 10, and the reservoir 100 is provided in a member (for example, the elastic film 50, the insulator film 55, etc.) interposed between the flow path forming substrate 10 and the protective substrate 30. An ink supply path 14 that communicates with each pressure generating chamber 12 may be provided.

  A piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 is provided in a region of the protective substrate 30 that faces the piezoelectric element 300. The piezoelectric element holding part 32 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed.

  As such a protective substrate 30, it is preferable to use substantially the same material as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, ceramic material, etc. In this embodiment, the same material as the flow path forming substrate 10 is used. The silicon single crystal substrate was used.

  The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is provided so as to be exposed in the through hole 33.

  A drive circuit 200 for driving the piezoelectric elements 300 arranged in parallel is fixed on the protective substrate 30. For example, a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 200. The drive circuit 200 and the lead electrode 90 are electrically connected via a connection wiring 210 made of a conductive wire such as a bonding wire.

  In addition, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film), and one surface of the reservoir portion 31 is sealed by the sealing film 41. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS)). Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head of the present embodiment, ink is taken in from an ink introduction port connected to an external ink supply means (not shown), and the interior from the reservoir 100 to the nozzle opening 21 is filled with ink, and then the drive circuit 200. In accordance with the recording signal from the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12, the elastic film 50, the insulator film 55, the first electrode 60, and the piezoelectric layer. By bending and deforming 70, the pressure in each pressure generating chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.

  Hereinafter, a manufacturing method and an inspection method of such an ink jet recording head will be described with reference to FIGS. 4 to 7 are cross-sectional views in the width direction of the pressure generating chamber showing the manufacturing method and the inspection method of the ink jet recording head which is an example of the liquid jet head according to the first embodiment of the present invention.

First, as shown in FIG. 4A, a silicon dioxide film 51 made of silicon dioxide (SiO ₂ ) constituting the elastic film 50 is formed on the surface of a flow path forming substrate wafer 110 that is a silicon wafer. Next, as shown in FIG. 4B, an insulator film 55 made of zirconium oxide is formed on the elastic film 50 (silicon dioxide film 51). Next, as shown in FIG. 4C, the first electrode 60 is formed on the entire surface of the insulator film 55 and patterned into a predetermined shape. The material of the first electrode 60 is not particularly limited. However, when lead zirconate titanate (PZT) is used as the piezoelectric layer 70, it is desirable that the material has little change in conductivity due to diffusion of lead oxide. . For this reason, platinum, iridium, etc. are used suitably as a material of the 1st electrode 60. FIG.

  Next, as shown in FIG. 5A, the piezoelectric layer 70 and the second electrode 80 are sequentially stacked on the first electrode 60. Here, in this embodiment, a so-called sol in which an organometallic compound is dissolved and dispersed in a solvent is applied, dried, gelled, and further fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. The piezoelectric layer 70 is formed using a gel method. In addition, the manufacturing method of the piezoelectric layer 70 is not limited to the sol-gel method, for example, using a PVD (Physical Vapor Deposition) method such as a MOD (Metal-Organic Decomposition) method, a sputtering method, or a laser ablation method. Also good. The second electrode 80 can be made of a highly conductive metal such as iridium (Ir).

  Next, as shown in FIG. 5B, the piezoelectric layer 70 and the inspection piezoelectric elements 300 </ b> A and 300 </ b> B are formed by simultaneously patterning the piezoelectric layer 70 and the second electrode 80. Specifically, by patterning the piezoelectric layer 70 and the second electrode 80, the piezoelectric element 300 is formed in a region opposite to the region where each pressure generating chamber 12 of the flow path forming substrate wafer 110 is formed. The inspection piezoelectric elements 300A and 300B are formed on both outer sides of the piezoelectric element 300 in the direction in which the piezoelectric elements 300 are arranged in parallel. That is, the inspection piezoelectric elements 300 </ b> A and 300 </ b> B are formed simultaneously with the piezoelectric element 300.

  Further, in the present embodiment, as shown in FIGS. 5B and 3, the piezoelectric elements 300 A and 300 B for inspection are distanced from the piezoelectric elements 300 at both ends arranged side by side. It is provided so as to be the same as the interval. This is because the piezoelectric elements 300A and 300B for inspection are provided at the same interval as the adjacent piezoelectric elements 300, and the piezoelectric element 300 receives stress such as tension and compression received by the adjacent piezoelectric elements 300A and 300B for inspection. This is because it can be the same as the stress generated between them.

  In addition, the inspection piezoelectric elements 300A and 300B are provided in a region to which the protective substrate 30 is bonded in the present embodiment. As a result, the area of the flow path forming substrate 10 can be prevented from being widened, and the ink jet recording head I can be prevented from being enlarged. Of course, the inspection piezoelectric elements 300 </ b> A and 300 </ b> B may be provided in a region where the flow path forming substrate 10 and the protective substrate 30 are not joined, for example, inside the piezoelectric element holding portion 32 or outside the protective substrate 30. Thereby, even after the protective substrate 30 is bonded to the flow path forming substrate 10, the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B can be measured.

  After forming the inspection piezoelectric elements 300A and 300B together with the piezoelectric element 300 in this way, the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B are measured (measurement process). In the present embodiment, so that the displacement condition can be stably measured while driving the piezoelectric element with several hundred million pulses, under the measurement conditions of applied voltage intensity: 150 to 300 kV / cm, applied frequency: 10 to 100,000 Hz, The hysteresis was measured by polarization (P) -electric field (E) of the inspection piezoelectric element 300A to derive saturation polarization, remanent polarization, and coercive electric field strength. Note that the measurement conditions are not limited to this range. An example of a hysteresis curve as a measurement result of the inspection piezoelectric element 300A is shown in FIG.

Then, the difference between the measurement results of these inspection piezoelectric elements 300A and 300B, that is, the fluctuation range is obtained, the fluctuation width of the saturation polarization is 5% or less, the fluctuation width of the residual polarization is 15% or less, and the coercive electric field It is derived whether or not the fluctuation range of the intensity is 15% or less, and whether or not the fluctuation range is a predetermined value or less is inspected (inspection process). In this case, in order to perform a simpler inspection without obtaining a fluctuation range, a difference in piezoelectric characteristics of the piezoelectric elements for inspection 300A and 300B is simply obtained, and whether or not this difference is included in a predetermined value corresponding to the above-described fluctuation range. You may inspect. That is, the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B are measured using the drive waveform (condition: period 66 Hz, applied voltage ± 35 V, drive waveform interval 0.1 seconds) shown in FIG. Whether the saturation polarization difference between the elements 300A and 300B is 1.2 μC / cm ² or less, the residual polarization difference is 2.5 μC / cm ² or less, and the coercive field strength difference is 7.69 kV / cm or less. Inspect whether. If the piezoelectric characteristics are within this fluctuation range, the ink ejection characteristics have little variation, so that the ink jet recording head in which the line width inclination is 6% and image quality unevenness is suppressed can be obtained.

  That is, in the present embodiment, the piezoelectric characteristics of the two inspection piezoelectric elements 300A and 300B are measured, and the difference between the piezoelectric characteristics of the two inspection piezoelectric elements 300A and 300B is derived. Based on these values It is possible to determine whether or not the piezoelectric elements 300A and 300B for inspection have an inclination equal to or less than a predetermined inclination in order to determine whether the ink jet recording head has no variation in the piezoelectric elements 300 in the parallel direction. In other words, it is possible to determine whether the ink jet recording head has good visibility as a result of the uniform (substantially uniform) ink ejection characteristics and the line width inclination within 6%.

  In the present embodiment, before the pressure generating chamber 12 is formed on the flow path forming substrate 10 (flow path forming substrate wafer 110), the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B (piezoelectric element 300) are measured. Therefore, it is possible to immediately detect defects in the manufacturing process such as the film forming process, the firing process and the lithography method of the piezoelectric element 300 (inspection piezoelectric elements 300A and 300B), and to provide feedback to the manufacturing process of the piezoelectric element 300. The occurrence of defective products due to defects in the manufacturing process of the piezoelectric element 300 can be reduced. In addition, the piezoelectric element 300 is inspected before the pressure generation chamber 12 is formed, and the quality determination is performed, so that the subsequent process of bonding the protective substrate 30, the process of forming the pressure generation chamber 12, and the like are useless. Never become.

  In the present embodiment, by applying a voltage to the inspection piezoelectric elements 300A and 300B and measuring the piezoelectric characteristics, there is no need to actually apply a voltage to the piezoelectric element 300 used for ink ejection for inspection. The so-called fatigue phenomenon in which the polarization direction of the piezoelectric element 300 is partially fixed does not occur. That is, when the piezoelectric characteristics are measured with the piezoelectric element 300 that is actually used for ink ejection, the piezoelectric characteristics of the piezoelectric element 300 to which a voltage is applied for measurement are deteriorated compared to the piezoelectric element 300 to which no voltage is applied. However, there is a possibility that variations in piezoelectric characteristics may occur, and this is suppressed.

  After inspecting the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B (that is, the piezoelectric characteristics of the piezoelectric element 300) in this way, the lead electrode 90 is formed. Specifically, as shown in FIG. 5C, after forming the lead electrode 90 over the entire surface of the flow path forming substrate wafer 110, for example, each through a mask pattern (not shown) made of resist or the like. Each piezoelectric element 300 is formed by patterning.

  In this embodiment, since the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B are measured before the lead electrode 90 is formed, the lead electrode 90 is not formed on the inspection piezoelectric elements 300A and 300B. However, the lead electrode 90 may be formed on the inspection piezoelectric elements 300A and 300B. Thereby, for example, when the inspection piezoelectric elements 300A and 300B are provided outside the bonding region, that is, in the piezoelectric element holding portion 32, the flow path forming substrate wafer 110 (the flow path forming substrate 10) is attached to the protective substrate wafer. After bonding 130 (protective substrate 30), the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B can be measured. Of course, whether or not the lead electrodes 90 are provided on the inspection piezoelectric elements 300A and 300B, after the lead electrodes 90 are formed on the piezoelectric element 300, the inspection piezoelectric elements 300A and 300B are provided. Measurement of piezoelectric characteristics of 300B may be performed.

  Next, as shown in FIG. 6A, a protective substrate wafer 130 which is a silicon wafer and serves as a plurality of protective substrates 30 is disposed on the piezoelectric element 300 side of the flow path forming substrate wafer 110 via an adhesive 35. Join.

  Next, as shown in FIG. 6B, the flow path forming substrate wafer 110 is thinned to a predetermined thickness. Next, as shown in FIG. 6C, a mask film 52 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape.

  Then, as shown in FIG. 7, the pressure corresponding to the piezoelectric element 300 is obtained by anisotropically etching (wet etching) the flow path forming substrate wafer 110 using an alkaline solution such as KOH through the mask film 52. A generation chamber 12 and the like are formed.

  In the present embodiment, the inspection piezoelectric elements 300A and 300B are provided in a region where the pressure generating chamber 12 is not formed. As a result, the rigidity of the flow path forming substrate 10 is reduced, and the flow path forming substrate 10 is broken, such as cracks, or warped when the flow path forming substrate 10 and the protective substrate 30 are expanded and contracted by heat. Thus, it is possible to reliably prevent the substrate from being broken such as a crack. Of course, the pressure generation chamber 12 may be formed in a region opposite to the inspection piezoelectric elements 300A and 300B. Incidentally, when the inspection piezoelectric elements 300A and 300B are measured after the pressure generating chamber 12 is formed, the inspection piezoelectric elements 300A and 300B are disposed in a region where the flow path forming substrate 10 and the protective substrate 30 are not bonded, for example, piezoelectric It is necessary to provide in the element holding part 32, the outer side of the protective substrate 30, etc.

  Thereafter, unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 are removed by cutting, for example, by dicing. Then, the nozzle plate 20 having the nozzle openings 21 formed on the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130 is bonded, and the compliance substrate 40 is bonded to the protective substrate wafer 130. Then, the flow path forming substrate wafer 110 and the like are divided into a single chip size flow path forming substrate 10 as shown in FIG.

Hereinafter, the measurement process and the inspection process will be described using examples. FIG. 5B shows a plurality of inspection piezoelectric elements 300A and 300B of each flow path forming substrate wafer 110 in the state shown in FIG. 5B (38 flow path forming substrates 10 are formed when divided). 9 was input as a drive waveform, and the piezoelectric characteristics of the inspection piezoelectric elements 300A and 300B were measured. The measurement results are shown in FIGS. 10 to 12 are graphs showing the results of the examples, in which the vertical axis indicates saturation polarization, the residual polarization difference, and the coercive electric field strength difference, and the horizontal axis indicates each flow path forming substrate wafer. For example, FIG. 10 shows the difference in saturation polarization of each flow path forming substrate 10 (1 to 38) in each flow path forming substrate wafer 110. As shown in FIGS. 10 to 12, in all the chips of each flow path forming substrate wafer 110, the difference in all saturation polarizations is 1.2 μC / cm ² or less, and the difference in residual polarization is 2.5 μC / cm ^2. cm ² or less, the difference between the coercive field strength was less 7.69kV / cm. In addition, after the two flow path forming substrate wafer chips were manufactured as liquid jet heads by a method described later, the inclination of the line width was examined. The results are shown in FIG. As shown in FIG. 13, all the line widths were within 5%. Therefore, it was found that the slope of the line width is within 6% when the fluctuation range is equal to or less than a predetermined value as described above.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the basic composition of this invention is not limited to what was mentioned above. In this embodiment, the inspection process is performed before the protective substrate wafer 130 is bonded to the piezoelectric element 300 side of the flow path forming substrate wafer 110, but at any stage after the piezoelectric element 300 is formed. Also good. For example, each inspection piezoelectric element 300A, 300B is provided with a lead electrode 90, and divided into chip-sized flow path forming substrate 10 and the like to form the ink jet recording head of this embodiment, and then an inspection process is performed. Also good.

  In the present embodiment, the inspection piezoelectric elements 300A and 300B are formed and the inspection process is performed. Of the piezoelectric elements 300 arranged in parallel, the inspection process is performed using the piezoelectric elements 300 at both ends in the parallel arrangement direction. Also good.

  In the first embodiment described above, a silicon single crystal substrate is exemplified as the flow path forming substrate 10, but the present invention is not particularly limited thereto. For example, a silicon single crystal substrate having a (100) crystal plane orientation is used. Alternatively, a material such as an SOI substrate or glass may be used.

  In the first embodiment described above, an ink jet recording head has been described as an example of a liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads, and is a liquid ejecting a liquid other than ink. Of course, the present invention can also be applied to an ejection head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  In the ink jet recording apparatus II shown in FIG. 14, the recording head units 1A and 1B having the ink jet recording head I are detachably provided with cartridges 2A and 2B constituting ink supply means, and the recording head units 1A and 1B. Is mounted on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

  In the ink jet recording apparatus II described above, the ink jet recording head I (head units 1A, 1B) is mounted on the carriage 3 and moves in the main scanning direction. However, the present invention is not particularly limited thereto. The present invention can also be applied to a so-called line recording apparatus in which the ink jet recording head I is fixed and printing is performed simply by moving the recording sheet S such as paper in the sub-scanning direction.

  I ink jet recording head (liquid ejecting head), 10 flow path forming substrate, 12 pressure generating chamber, 13 communicating portion, 14 ink supply path, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 31 reservoir portion, 32 piezoelectric element Holding part, 40 compliance substrate, 60 first electrode, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 reservoir, 200 drive circuit, 210 connection wiring, 300 piezoelectric element, 300A, 300B inspection piezoelectric element

Claims (5)

A pressure generating chamber arranged in parallel with each of a plurality of nozzle openings for ejecting liquid, a plurality of piezoelectric elements for causing a pressure change in each pressure generating chamber, and a piezoelectric element group including a plurality of the piezoelectric elements A pair of inspection piezoelectric elements provided on both outer sides of the piezoelectric elements in the parallel direction,
The piezoelectric layer of the pair of inspection piezoelectric elements has a saturation polarization fluctuation range of within 5%, a residual polarization fluctuation range of within 15%, and a coercive field strength fluctuation range of within 15%. A liquid jet head characterized by the above. The piezoelectric layers of the pair of piezoelectric elements for inspection have a difference in saturation polarization of 1.2 μC / cm ^{2 or} less, a difference in residual polarization of 2.5 μC / cm ^{2 or} less, and a difference in coercive electric field strength. The liquid jet head according to claim 1, wherein the liquid jet head is within 7.69 kV / cm.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1. A flow path forming substrate in which a liquid flow path including a plurality of pressure generating chambers communicating with a nozzle for ejecting liquid droplets is formed, and a pressure change is provided in each pressure generating chamber provided on one side of the flow path forming substrate. And a pair of inspection piezoelectric elements provided on both outer sides of the piezoelectric elements in a parallel arrangement direction of a piezoelectric element group of a plurality of piezoelectric elements.
A plurality of piezoelectric elements are formed by laminating and patterning a first electrode, a piezoelectric layer and a second electrode on one surface side of a flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening for ejecting liquid is formed. And a pair of inspection piezoelectric elements each including the first electrode, the piezoelectric layer, and the second electrode on both outer sides of the piezoelectric elements in the parallel arrangement direction of the piezoelectric element group of the plurality of piezoelectric elements. Further comprising the step of forming
A measuring step for measuring the piezoelectric characteristics of the pair of inspection piezoelectric elements;
From the piezoelectric characteristics, the fluctuation range of the saturation polarization, remanent polarization and coercive electric field strength of the piezoelectric element for inspection is calculated, the fluctuation range of the saturation polarization is within 5%, and the fluctuation range of the remanent polarization is within 15%. And a determination step of determining whether or not the fluctuation range of the coercive electric field strength is within 15%. In the determination step, the saturation polarization difference is within 1.2 μC / cm ² , the residual polarization difference is within 2.5 μC / cm ² , and the coercive field strength difference is 7.69 kV / The method of manufacturing a liquid jet head according to claim 4, wherein it is determined whether or not the distance is within cm.