JP2005271543A - Inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head to discharge ink by using a deformation of piezoelectric elements and a printer with the head, wherein speed fluctuation due to crosstalk is suppressed, and discharge characteristics in a high frequency are improved. <P>SOLUTION: A shortage of rigidity in a fluid passage forming member due to high density is compensated by providing a reinforcing member between a supporter and a housing. An adhesive to bond piezoelectric elements is partitioned among the piezoelectric elements. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an increase in density of an ink jet printer that forms an ink image on a printing medium by applying pressure to the ink by a piezoelectric element to form an ink image, and to improve ejection characteristics at a high frequency.

  2. Description of the Related Art Conventionally, there is known an ink jet head that discharges ink from nozzles by changing the volume of a pressure chamber using pressure generating means such as a piezoelectric element (see, for example, Patent Document 1).

  FIG. 10 shows an example of an ink jet head using a piezoelectric element. The ink flow path is formed by joining one or more thin plates. In the example of FIG. 10, the nozzle plate 2 having the nozzle 1, the chamber plate 5 in which the pressure chamber 4 is formed, and a list for controlling the ink inflow into the pressure chamber 4 by connecting the common ink passage 13 and the pressure chamber 4. The restrictor plate 7 on which the restrictor 6 is formed is positioned and joined. Further, the diaphragm plate 10 on which the diaphragm 8 for transmitting the pressure of the piezoelectric actuator 14 to the pressure chamber 4 is formed and the support plate 11 having the hole 11a that defines the vibration region of the diaphragm 8 are positioned and joined. . These thin plates are bonded together to form the flow path forming substrate 3, and the housing 12 in which the common ink path 13 is formed is positioned and joined in the same manner.

  Finally, the piezoelectric actuator 14 including the plurality of piezoelectric elements 15 and the support substrate 16 that fixes the piezoelectric elements 15 is positioned and joined. The piezoelectric actuator 14 includes a plurality of piezoelectric elements 15, and each piezoelectric element 15 corresponds to one pressure chamber 4. Each piezoelectric element 15 has an individual electrode 17 and a common electrode connected to the back side, and the piezoelectric element 15 is deformed by applying a selective electrical signal to the individual electrode 17. The deformation of the piezoelectric element 15 is transmitted to the pressure chamber 4 through the vibration plate 8, and ink is ejected from the nozzle 1 as ink droplets.

  However, the ink jet head using the deformation of the piezoelectric element 15 is different from the ink drop discharge speed in the single drive and the ink drop discharge speed in the plural nozzle drive due to two causes as the density increases. Has the problem of crosstalk. Further, when driven at a high frequency, there is a problem of frequency dependency in which the speed changes under the influence of the drive nozzle itself, that is, a so-called crosstalk with itself.

  The first crosstalk caused by the first cause is that the rigidity of the flow path forming substrate 3 is insufficient, and not only the diaphragm 8 but also the flow path forming substrate 3 itself is deformed according to the number of piezoelectric elements 15 driven. It is a problem. If the flow path forming substrate 3 is deformed, the apparent deformation amount of the piezoelectric element 15 is reduced, and the discharge speed is lowered. The rigidity of the flow path forming substrate 3 greatly depends on the width of the opening of the housing 12. In the case of general machining, the accuracy of the opening of the housing 12 is about ± 0.1 mm. A wide opening has poor crosstalk characteristics, and a narrow opening has relatively good results, and the crosstalk characteristics vary from inkjet head to inkjet head.

  The second cause of the second crosstalk is that the piezoelectric elements 15 are connected to each other by an adhesive in the inkjet head using the piezoelectric elements 15, and the deformation of the adjacent piezoelectric elements 15 vibrates via the connected adhesive. This is a problem that is transmitted to the plate 8. When the deformation of the adjacent piezoelectric element 15 is transmitted to the vibration plate 8, the apparent deformation amount of the piezoelectric element 15 increases and the speed increases.

  Crosstalk with itself occurs for the same reason as the first crosstalk. Due to insufficient rigidity of the flow path forming substrate 3, residual vibration occurs in the flow path forming substrate 3 even after ejection. The entire meniscus of ink in the nozzle 1 vibrates due to residual vibration, and the ejection speed decreases when driven at a high frequency. Therefore, it has been an obstacle to drive the ink jet head at a higher driving frequency.

  Conventionally, the following inventions have been disclosed as means for solving the above-described crosstalk.

  As a method for solving the crosstalk caused by the first cause, a method is known in which piezoelectric elements and non-moving piezoelectric elements are alternately arranged in a row to prevent deformation of the flow path forming substrate (for example, Patent Documents). 2). An example is shown in FIG. Since the immovable piezoelectric element 130 disposed between the piezoelectric elements 115 directly supports the flow path formation 3, there is an effect of preventing deformation due to driving of the piezoelectric element 115. However, this method requires doubling the pitch of the piezoelectric elements 115 and is not suitable for increasing the density.

  In addition, a method is known in which a thick portion is provided in the partition wall of the flow path forming substrate to increase the rigidity of the flow path forming substrate itself (see, for example, Patent Document 3). An example is shown in FIG. Rigidity is enhanced by providing a thick portion 105 a in a part of the partition wall 105 that separates the adjacent pressure chambers 104. However, in this method, the structure of the pressure chamber 104 is limited, and there is a limit to increase the rigidity under the restriction of high density, and crosstalk cannot be effectively prevented.

  A method of providing a reinforcing member between a pressure chamber forming member and a nozzle forming member is also known (see, for example, Patent Document 4). An example is shown in FIG. Rigidity is enhanced by providing a reinforcing member 140 having a communication hole 141 corresponding to the nozzle 101 between the pressure chamber forming member 105 having a plurality of pressure chambers and the plurality of nozzles 101 corresponding to each pressure chamber. However, in this method as well, the reinforcing member 140 forms a part of the ink flow path. Therefore, if the thickness is increased to increase the rigidity, the distance from the pressure chamber to the nozzle is increased, and sufficient discharge performance cannot be obtained. .

  Although there is a method of providing the reinforcing member 140 on the nozzle substrate 101, the space between the nozzle 101 and the printing medium is widened, which causes deterioration of the ink landing position accuracy.

  There is also known a method of disposing a frame-like elastic plate on the surface side to which the piezoelectric element of the elastic plate is bonded (see, for example, Patent Document 5). An example is shown in FIG. The frame 111a supports the partition wall of the pressure chamber 104 and supplements the rigidity of the flow path forming substrate. In addition, the frame 111 a defines a vibration region in the longitudinal direction of the diaphragm 108. However, in order to ensure compliance, the vibration region becomes elongated as compared with the case of low density as the density increases, and the frame 111a becomes thin. On the other hand, it is difficult to narrow the housing openings 112a and 112b that support the frame 111a at both ends. Therefore, the rigidity of the frame 111a is reduced by increasing the density. Furthermore, when the frame 111a is manufactured by an etching method, a precision press method, a laser processing, etc. of a thin plate of stainless steel, the thickness becomes about 0.2 mm, and there is a problem that sufficient strength cannot be obtained only by the frame 111a. there were. Furthermore, the frame 111a defines the vibration area of the diaphragm 108, and the piezoelectric element 115 is inserted between them, so that accuracy is required. Since there is a trade-off relationship between the thickness and accuracy of the plate, it has been difficult to achieve both sufficient rigidity and accuracy at the same time.

  Conventionally, the following inventions have been disclosed as means for solving the crosstalk caused by the second cause.

  A method of installing a frame that defines the spread of the adhesive is known (see, for example, Patent Document 6). An example is shown in FIG. The adhesive 150 spreads on the vibration plate 108 when cured, but the spread is defined by the frame 111a. The adhesive 130 covers the entire surface of the vibration plate 108 in the frame 111a, thereby reducing variations in ink ejection. However, when the adhesive 150 is applied so as to cover the entire surface of the diaphragm 108, the conventional frame 111 a crosses the frame 111 a and is connected by the adhesive 150, and the adjacent diaphragm is interposed via the adhesive 150 when the piezoelectric element 115 is driven. The deformation is transmitted to 108, and as a result, there is a problem of causing the second crosstalk.

JP-A-1-115638

Japanese Patent Laid-Open No. 9-174837 JP 2001-199063 A JP-A-6-99578 JP-A-6-297710 JP 2002-331671 A

  The problem to be solved is the deformation of the flow path forming substrate and the increase of crosstalk via the adhesive between the piezoelectric elements as the density of the ink jet head increases.

  The most important aspect of the present invention is to provide at least one reinforcing member between the support portion and the housing in order to increase the rigidity of the flow path forming substrate and eliminate the interaction between the piezoelectric elements via the adhesive. Features.

  In order to solve the above problems, in the present invention, a nozzle substrate in which a plurality of nozzles for ejecting ink droplets are arranged in rows, a pressure chamber for storing ink corresponding to the nozzles, and the pressure by applying an electric signal. A piezoelectric element that generates pressure fluctuation in the chamber; a diaphragm that forms a part of the wall surface of the pressure chamber and is connected to the piezoelectric element by an adhesive; and is disposed on the diaphragm, and is disposed in the pressure chamber. A list having a hole portion into which the piezoelectric element is inserted in an opposing portion, a support portion that defines at least a part of a deformation region of the diaphragm by the hole portion, and a flow path for supplying ink to the pressure chamber A hole provided in the support part in an ink jet printer having a restrictor and a housing having a common ink passage for supplying ink to the restrictor and an opening into which the piezoelectric element group is inserted. Has a slit hole that corresponds to, and a reinforcing member of high rigidity than the support portion, characterized in that arranged at least one or more between the housing and the support portion.

  Further, the rigidity of the nozzle substrate, the pressure chamber, the restrictor, the diaphragm, the support plate and the flow path forming substrate combined with the reinforcing member is a static deformation generated on the surface of the nozzle substrate due to the deformation of the piezoelectric element. It is characterized in that the amount is 5% or less of the deformation amount of the piezoelectric element.

  The longitudinal length of the slit hole portion of the reinforcing member is not more than the longitudinal length of the hole portion of the support portion.

  The width in the short direction of the slit hole portion of the reinforcing member is equal to or greater than the width in the short direction of the hole portion of the support portion.

  Further, the adhesive for joining the piezoelectric element and the diaphragm covers the entire diaphragm surrounded by the support portion.

  Furthermore, the thickness of the adhesive is not less than the thickness of the support part and not more than the total thickness of the support part and the reinforcing member.

  The purpose of suppressing crosstalk while achieving high density was realized without restricting the ink flow path design.

  Hereinafter, an example of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view for explaining the structure of the main part of the ink jet head of the present invention.

  The flow path forming substrate 3 is formed by joining one or more thin plates.

  The nozzle substrate 2 on which the plurality of nozzles 1 are formed and the chamber plate 5 on which the pressure chambers 4 are formed are positioned and joined. Next, the common ink passage 13 and the pressure chamber 4 are connected to each other and joined to a restrictor plate 7 that forms a restrictor 6 that controls the inflow of ink into the pressure chamber 4. A diaphragm plate 10 having a diaphragm 8 for efficiently transferring the pressure of the piezoelectric actuator 14 to the pressure chamber 4 and a filter portion 9 for removing dust and the like in the ink flowing into the restrictor 6 from the common ink passage 13; The support plate 11 having the hole 11a that defines the vibration region of the diaphragm 8 is positioned and joined. The flow path forming substrate 3 is formed by laminating these thin plates.

  A piezoelectric actuator 14 including a plurality of piezoelectric elements 15 and a support substrate 16 that fixes the piezoelectric elements 15 is provided. The piezoelectric actuator 14 is inserted into a hole formed in the housing 12 and joined to the diaphragm 8.

  Between the flow path forming substrate 3 and the housing 12, at least one reinforcing plate 20 having rigidity higher than that of the support plate is disposed and similarly positioned and joined. The reinforcing plate 20 has a slit hole 20 a corresponding to the hole 11 a of the support plate 11.

  The nozzle substrate 2 is formed by stainless precision pressing, laser processing, nickel electroforming, or the like. The chamber plate 5, the restrictor plate 7, the diaphragm plate 10, the support plate 11, and the reinforcing plate 20 are made by a stainless steel etching method, a precision press method, a laser processing, or a nickel material electroforming method.

  The housing 12 has a common ink passage 13 and is formed by cutting stainless steel or the like, and an ink introduction pipe 18 that guides ink from an ink cartridge (not shown) to the common ink passage 13 is joined thereto.

  FIG. 5 shows, as a conventional example, the deformation of the surface of the nozzle plate 2 and the change in the discharge speed when the number of piezoelectric elements that are driven simultaneously in the conventional structure without the reinforcing plate 20 is increased.

  In this conventional example, the material of each plate constituting each flow path substrate 3 is stainless steel, and the thickness of each plate is about 0.075 to 0.25 mm, excluding the diaphragm plate. Is about 0.5 mm. The amount of deformation of the nozzle plate 2 was determined by analysis using a finite element method. The horizontal axis in FIG. 5 indicates the number of piezoelectric elements that are driven simultaneously. The vertical axis on the left indicates the discharge speed (%) when driving a plurality of nozzles when the discharge speed when driving alone is 100%. The vertical axis on the right side shows the deformation amount (%) generated on the surface of the nozzle plate 2 when the deformation amount of the piezoelectric element is 100%. As the number of piezoelectric elements that are driven simultaneously increases, the ejection speed decreases due to crosstalk. The amount of deformation of the nozzle plate 2 increases as the discharge speed decreases. In the example of FIG. 5, the discharge speed is reduced to about 30% compared to the single drive.

  The deformation of the nozzle plate 2 occurs because a force is applied to the flow path forming substrate 3 through the vibration plate 8 when the piezoelectric element 15 contracts. The deformation of the surface of the nozzle plate 2 increases as the rigidity of the flow path forming substrate 3 becomes insufficient. When the flow path forming substrate 3 is deformed, the deformation amount of the vibration plate 8 is reduced, the pressure fluctuation in the pressure chamber 4 is reduced, and the discharge speed is reduced.

  FIG. 6 shows the results of experiments and stiffness analysis using samples in which the stiffness of the flow path forming substrate 3 is changed.

  The vertical axis in FIG. 6 represents the ratio (%) of the ejection speed when driving a plurality of nozzles with respect to the ejection speed by single drive, and the horizontal axis represents the ratio (%) of the maximum deformation amount of the surface of the nozzle plate 2 to the deformation amount of the piezoelectric element. Show. From this, it can be seen that the smaller the deformation generated in the nozzle plate, the smaller the fluctuation of the discharge speed.

  Generally, it is known that a practical speed fluctuation tolerance of an inkjet head is within 10%. From this experimental result, it was found that the deformation of the nozzle plate 2 needs to be suppressed to 5% or less of the deformation amount of the piezoelectric element in order to suppress the speed fluctuation due to the crosstalk within 10%.

  The thickness of the reinforcing plate 20 may be designed according to the following procedure. First, dimensions such as the thickness of each thin plate constituting the flow path forming substrate 3 and the width of the flow path are designed so that desired ink discharge characteristics such as discharge speed and weight can be obtained. Next, the necessary thickness of the reinforcing plate 20 may be calculated by rigidity analysis including the reinforcing plate 20.

  FIG. 7 shows deformation that occurs in the nozzle plate 2 when the thickness of the reinforcing plate 20 is changed.

  In this example, in order for the flow path forming substrate 3 and the reinforcing plate 20 to have sufficient rigidity, it can be said that the reinforcing plate needs to be at least 0.3 mm or more. However, the thickness of the reinforcing plate 20 shown here is an example, and the required thickness depends on the pitch of the piezoelectric elements 15, the width of the opening of the housing 12, and the material and shape of each thin plate of the flow path forming substrate 3. To do.

  By configuring the support plate 11 and the reinforcing plate 20 separately, the support plate 11 can be processed with an emphasis on accuracy, for example, etching processing with a thinner plate thickness, precision press processing, and the like. While the vibration region of the diaphragm 8 is accurately defined by the support plate 11, the reinforcing plate 20 can be provided with rigidity independently.

  It may be difficult to accurately process a thin plate of stainless steel or the like with sufficient rigidity by an etching method, a precision press method, laser processing, or the like. In any case, a thickness of about 0.1 to 0.25 mm is the limit of processing. In this case, a plurality of reinforcing plates 20 may be configured to overlap each other so as to obtain necessary rigidity.

  FIG. 8 is a diagram showing the relationship between the number of drives and the speed fluctuation in the conventional case where the reinforcing plate 20 is not provided and in the case of the present invention provided. The symbol ♦ indicates the case where the reinforcing plate 20 is not provided, and the symbol □ indicates the speed fluctuation when the reinforcing plate 20 is provided. It can be seen that the crosstalk characteristic is greatly improved by providing the reinforcing plate 20.

  Furthermore, by providing the reinforcing plate 20, in addition to being able to suppress crosstalk, it is possible to suppress variations in crosstalk characteristics for each inkjet head. The accuracy of the width of the opening of the housing 12 is about ± 0.1 mm, whereas the accuracy of the reinforcing plate 20 is generally about 0.01 to 0.05 mm. Since the reinforcing plate 20 itself is rigid and the variation in the crosstalk characteristics depends on the accuracy of the width of the reinforcing plate 20, there is an effect that the variation in the crosstalk characteristics for each head is reduced.

  Further, since the processing accuracy of the reinforcing plate 20 is higher than that of the housing 12, the distance from the piezoelectric element 15 or the support substrate 16 can be reduced, and the effect of supporting the flow path forming substrate 3 can be further enhanced. That is, while the housing has a block shape and a relatively thick structure, the reinforcing plate is, for example, a plate having a thickness of 0.2 mm, and the processing accuracy of the reinforcing plate 20 is higher than that of the housing. It is relatively easy. Therefore, it is possible to reduce the distance from the piezoelectric element 15 and to support the flow path forming substrate 3 by manufacturing the hole size of the reinforcing plate with higher accuracy than the accuracy (± 0.1 mm) of the opening of the housing. The effect can be further enhanced.

  2 and 3 are cross-sectional views of the ink jet head of this embodiment, and FIG. 4 is a structural view as seen from the piezoelectric element side.

  FIG. 2 shows a cross-sectional view in a direction perpendicular to the nozzle row.

  The longitudinal length L1 of the slit hole 20a of the reinforcing plate 20 is equal to or less than the longitudinal length L2 of the hole 11a of the support plate 11. By adopting such a structure, the rigidity of the reinforcing plate 20 becomes higher, and there is an effect of suppressing the occurrence of crosstalk when compared with the same thickness. The length of L1 may be set such that the reinforcing plate 20 and the piezoelectric element 15 do not touch each other when a cumulative error such as misalignment, dimensional error, and assembly accuracy is expected.

  FIG. 3 shows a cross-sectional view in the nozzle row direction.

  The width W1 in the short direction of the slit hole 20a of the reinforcing plate 20 is equal to or greater than the width W2 in the short direction of the hole 11a of the support plate 11. Due to the positional displacement and dimensional error in the reinforcing plate 20 and the bonding displacement with the support plate 11, the slit hole portion 20 a of the reinforcing plate 20 and the hole portion 11 a of the support plate 11 are displaced. If the displacement occurs, the reinforcing plate 20 and the piezoelectric element 15 may come into contact with each other. By setting the width W1 of the slit hole 20a of the reinforcing plate 20 to be equal to or larger than the width W2 of the hole 11a of the support plate 11, the reinforcing plate 20 and the piezoelectric element 15 do not contact each other. The width W1 may be set so that the reinforcing plate 20 does not cover the hole 11a when a cumulative error such as a positional deviation, a dimensional error, and a bonding accuracy of the reinforcing plate 20 is expected.

  FIG. 4 is a structural view seen from the piezoelectric element side. 2 and 3, the reinforcing plate 20 covers the slit hole 20a of the support plate 11 in the longitudinal direction. In the short direction, the slit hole 20a of the support plate 20 is not applied.

  FIG. 9 shows the relationship between the drive frequency and the discharge speed in the conventional case where the reinforcing plate 20 is not provided and in the case of the present invention provided.

  In the conventional example, in addition to the speed fluctuation caused by so-called Helmholtz vibration, the discharge speed gradually decreases as the drive frequency increases. On the other hand, in the present invention, although there is a speed fluctuation due to Helmholtz vibration, there is no overall decrease in the discharge speed.

  Since the rigidity of the flow path forming substrate 3 is supplemented by the reinforcing plate 20, the residual vibration of the flow path forming substrate 3 due to the driving of the piezoelectric element 15 is small, the meniscus vibration is small, and the speed reduction is small. Therefore, it is possible to use up to a higher frequency than in the conventional example.

  FIG. 16 is a schematic view in consideration of the adhesive 50 between the piezoelectric element 15 and the diaphragm 8.

  The adhesive 50 is controlled to have a constant thickness and transferred to the piezoelectric element 15, thereby bonding the piezoelectric element 15 and the diaphragm 8 in a uniform amount.

  Here, when the adhesive 50 is small and the diaphragm 8 surrounded by the hole 11a of the support plate 11 is not filled, compliance of the diaphragm 8 and the adhesive 50 varies due to variations in the flow of the adhesive. When compliance varies, ink ejection characteristics vary from nozzle to nozzle.

  Therefore, it is desirable to cover the entire surface of the diaphragm 8 with the adhesive 50 in order to align the discharge characteristics for each nozzle. Furthermore, in order to ensure compliance when the adhesive 50 and the diaphragm 8 are combined, the adhesive 50 is desirably a soft adhesive having a Shore hardness of 80 degrees or less.

  When an amount of the adhesive 50 that can fill the entire surface of the diaphragm 8 is transferred to the piezoelectric elements 15, the adhesive 50 also enters between the piezoelectric elements 15. Furthermore, the thickness of the adhesive 50 may exceed the hole 11a of the support plate 11.

  In the case of the conventional structure, when the piezoelectric element 15 is connected by the adhesive 50, the deformation propagates to the adjacent diaphragm 8 and second crosstalk occurs.

  However, in the case of the present invention, since the reinforcing plate 20 is provided between the piezoelectric elements 15, the deformation of the adjacent piezoelectric elements 15 is less likely to be transmitted as compared to the case where the reinforcing plate 20 is not provided. The reinforcing plate 20 has an effect of partitioning the piezoelectric elements 15, and second crosstalk generated through the adhesive 50 can be effectively suppressed. Further, the thickness of the adhesive 50 can be applied more than the thickness of the support plate 11, and should preferably be less than the total thickness of the support plate 11 and the reinforcing plate 20.

  The degree of influence of crosstalk varies not only with the number of driven nozzles but also with the position of the nozzle to be driven. According to the present invention, it is possible to reduce variations in ink discharge speed and discharge weight for each nozzle by suppressing crosstalk. Therefore, for example, when performing solid printing, printing with small variations in print density and film thickness can be performed with a constant discharge amount.

It is the perspective view which showed one Example of this invention inkjet head. (Example 1) It is the top view which showed one Example of this invention inkjet head. (Example 1) It is sectional drawing which showed one Example of this invention inkjet head. (Example 1) It is sectional drawing which showed one Example of this invention inkjet head. (Example 1) It is a figure which shows the deformation | transformation and speed change of the nozzle plate of the conventional inkjet head. It is a figure which shows the deformation | transformation and speed change of a nozzle plate by crosstalk. It is a figure which shows the thickness of a reinforcement plate, and a deformation | transformation of a nozzle plate. It is a figure which shows the speed change of the inkjet head of this invention. It is a figure which shows the frequency characteristic of the prior art example and the inkjet head of this invention. It is the perspective view which showed the prior art example. It is sectional drawing which showed the prior art example. It is the top view and sectional drawing which showed the prior art example. It is the perspective view which showed the prior art example. It is the perspective view which showed the prior art example. It is sectional drawing which showed the prior art example. It is sectional drawing which showed the Example of this invention which considered the adhesive agent (Example 2).

Explanation of symbols

1 is a nozzle, 2 is a nozzle plate, 3 is a flow path forming substrate, 4 is a pressure chamber, 5 is a chamber plate, 6 is a restrictor, 7 is a restrictor plate, 8 is a diaphragm, 9 is a filter unit, and 10 is a diaphragm Plate, 11 support plate, 12 housing, 13 common ink passage, 14 piezoelectric actuator, 15 piezoelectric element, 16 support substrate, 17 individual electrode, 18 ink introduction pipe, 20 reinforcing plate, 50 It is an adhesive.

Claims (6)

A nozzle substrate in which a plurality of nozzles for discharging ink droplets are arranged in a line; a pressure chamber for storing ink corresponding to the nozzle; a piezoelectric element for generating pressure fluctuations in the pressure chamber by application of an electrical signal; A diaphragm that forms part of the wall surface of the pressure chamber and is connected to the piezoelectric element by an adhesive, and the piezoelectric element that is disposed on the diaphragm and that faces the pressure chamber is inserted into the diaphragm. A support portion that has a hole portion and defines at least a part of the deformation region of the diaphragm by the hole portion, a restrictor that is a flow path that supplies ink to the pressure chamber, and supplies ink to the restrictor A housing having a common ink passage and an opening into which the piezoelectric element group is inserted;
At least one or more reinforcing members having slit hole portions corresponding to the hole portions provided in the support portion and having higher rigidity than the support portion are disposed between the support portion and the housing. Inkjet head characterized.   The rigidity of the nozzle substrate and the pressure chamber, the restrictor, the diaphragm, the flow path forming substrate including the support portion, and the reinforcing member combined with each other is a static deformation amount generated on the nozzle substrate surface due to the deformation of the piezoelectric element. 2. The ink jet head according to claim 1, wherein the ink jet head has a rigidity of 5% or less of a deformation amount of the piezoelectric element.   The inkjet head according to claim 1, wherein a longitudinal length of the slit hole portion of the reinforcing member is equal to or less than a longitudinal length of the hole portion of the support portion.   The inkjet head according to claim 1, wherein a width in a short direction of the slit hole portion of the reinforcing member is equal to or greater than a width in a short direction of the hole portion of the support portion.   The inkjet head according to claim 1, wherein an adhesive that joins the piezoelectric element and the diaphragm covers the entire surface of the diaphragm surrounded by the support portion. The inkjet head according to claim 1, wherein the adhesive has a thickness that is equal to or greater than a thickness of the support portion and equal to or less than a total thickness of the support portion and the reinforcing member. .

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