JP2008094019A - Droplet discharge head and droplet discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a droplet discharge head which can stably discharge droplets by efficiently heating piezoelectric elements and the periphery of the piezoelectric elements by a simple structure, and to provide a droplet discharge device. <P>SOLUTION: The inkjet recording head 32 has heating resistors 37 on a piezoelectric element board 71 having piezoelectric elements 60 having piezoelectric elements 60, an upper electrode 64 provided on one side of the piezoelectric elements 60 and a lower electrode 58 provided on the other side of the piezoelectric element 60, a TEOS film 54 provided with the lower electrode 58 of the piezoelectric element 60 on one side, a LOCOS film 44 provided on the other side of the TEOS film 54, a first electric wiring 52 formed between the TEOS film 54 and the LOCOS film 44, a second electric wiring 56 connecting the first electric wiring 52 and the lower electrode 58. The inkjet recording device 10 has the recording head. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a droplet discharge head and a droplet discharge device that form an image on a recording medium by discharging an internal liquid as droplets.

  Conventionally, as a droplet discharge head, a droplet discharge device including a piezo-type droplet discharge head that forms an image on a recording medium by selectively discharging ink droplets from a plurality of nozzles of an inkjet recording head is known. (For example, refer to Patent Document 1).

  In such a piezo-type droplet discharge head, each of the plurality of piezoelectric elements is deformed by applying a driving signal such as voltage or magnetism to the plurality of piezoelectric elements, and is provided corresponding to each piezoelectric element. The ink stored in the pressure chamber is ejected, and ink droplets are ejected from each of the plurality of nozzles to form an image. At this time, each piezoelectric element generates heat due to the application of a drive signal, and therefore, when the driving frequency between the plurality of piezoelectric elements varies depending on the image to be formed, the piezoelectric element is stored in the pressure chamber corresponding to the piezoelectric element having a high temperature. The viscosity of the droplets decreases, the viscosity of the droplets stored in the pressure chamber corresponding to the piezoelectric element having a low temperature increases, and even when the same drive signal is input, the amount of ejected ink droplets varies. There was a case.

  For this reason, a heater for heating the ink to the droplet discharge head is provided to heat the ink inside the recording head as the droplet discharge head to a uniform temperature (for example, Patent Document 1), or a piezoelectric element. A technique for heating ink in a droplet discharge head to a uniform temperature using heat generation (see, for example, Patent Document 2) is known.

  In the technique of Patent Document 1, a heater for heating ink is integrally formed on the bottom surface of a nozzle plate on which nozzles for ejecting ink are formed, so that the inside of an ink flow path provided adjacent to the nozzle plate is provided. The ink can be heated to a uniform temperature.

  Further, in the technique of Patent Document 2, by using heat generated by driving a piezoelectric element, a driving pulse that does not eject ink is applied to the piezoelectric element, so that the piezoelectric element generates heat to heat the ink.

JP 2000-289204 A JP 2005-238846 A Japanese Patent Laid-Open No. 2001-80062

  However, in the technique of Patent Document 1, since the heater is provided on the nozzle plate formed on the substrate separately from the substrate provided with the piezoelectric element, the driving element for driving the piezoelectric element is connected to the piezoelectric element. In addition to providing wiring for the substrate on the substrate and wiring for connecting the driving element for driving the heater and the heater to the nozzle plate, the structure is complicated and the manufacturing process is complicated. There is concern about inviting.

  In the technique of Patent Document 2, since ink is heated using heat generated by driving a piezoelectric element, not only conversion of an electric signal into thermal energy but also conversion of an electric signal into deformation energy of the piezoelectric element. Therefore, there is a concern that energy efficiency is poor.

  The present invention has been made in view of the above-described problems, and is a liquid droplet ejection head and a liquid droplet that are capable of efficiently discharging a piezoelectric element and the periphery of the piezoelectric element with a simple configuration and stably ejecting liquid droplets. An object is to provide a discharge device.

  In order to achieve the above object, a droplet discharge head according to claim 1 of the present invention includes a piezoelectric body, a first electrode provided on one side of the piezoelectric body, and the other side of the piezoelectric body. A piezoelectric element having a second electrode provided on the first layer, a first layer on one side of which the second electrode of the piezoelectric element is provided, and a first layer provided on the other side of the first layer. 2 layers, a first electrical wiring formed between the first layer and the second layer, and a second electrical wiring connecting the first electrical wiring and the second electrode The piezoelectric element substrate has a heating resistor that generates heat.

  According to the droplet discharge head of the first aspect, since the heat generating resistor that generates heat is provided on the same piezoelectric element substrate as the piezoelectric element, the heat generating resistor can be efficiently heated with a simple configuration. The heat generated by the heating resistor can heat the piezoelectric element and the periphery of the piezoelectric element. For this reason, the viscosity of the liquid in the droplet discharge head can be stabilized by heating, and even when a high-viscosity liquid is used, the viscosity can be lowered and stable droplet discharge can be performed. . Accordingly, it is possible to efficiently heat the liquid around the piezoelectric element with a simple configuration and to realize stable liquid droplet ejection.

  According to the droplet discharge head of the first aspect, since the first electric wiring is formed between the first layer and the second layer, the degree of freedom in routing the electric wiring can be improved. Thus, the droplet discharge head can be reduced in size.

  The liquid droplet ejection head according to claim 2, wherein the heating resistor is formed on the piezoelectric body, the first layer, the second layer, and the liquid ejection head according to claim 1. The first wirings can be stacked via at least one of the first wirings. For this reason, a droplet discharge head can be reduced in size.

  According to a third aspect of the present invention, in the liquid droplet ejection head according to the first aspect, the heating resistor can be laminated on the piezoelectric body. For this reason, the piezoelectric body can be efficiently heated by the heat generated by the heating resistor, and the droplet discharge head can be downsized.

  A droplet discharge head according to a fourth aspect of the present invention is the droplet discharge head according to the first aspect, wherein the heating resistor is provided in a meandering manner along the surface of the piezoelectric element. When the heating resistor is provided in a meandering manner so that the heating resistor is heated by applying a driving voltage to the heating resistor, the same driving voltage is applied as compared to the case where the present invention is not adopted. Even in this case, a larger heat generation effect can be obtained. For this reason, the heating resistor can be efficiently heated.

According to a fifth aspect of the present invention, in the liquid droplet ejection head according to the first aspect, the heating resistor is formed by laminating a self-oxidation film on the heating resistor layer.
The self-oxidation film is formed by self-oxidizing the surface of the heating resistor layer.
Further, the heating resistor is configured to include a silicide of Ta, and in particular, may be configured to include TaSiO.

According to the droplet discharge head of the sixth aspect, the surface of the heating resistor layer is self-oxidized to form a self-oxidizing film without separately depositing an oxide film (insulating film) on the heating resistor layer. Therefore, the oxide film (insulating film) can be made thin, and heat loss due to heat generation of the heating resistor can be suppressed.
In addition, when the heating resistor is configured to include a silicide of Ta such as TaSiO, a self-oxidized film as an insulating film can be formed on the surface by thermal oxidation.

  The droplet discharge head according to claim 9, comprising: a pressure chamber that communicates with a nozzle that discharges a droplet and is filled with a liquid; and a flow path that supplies the liquid to the pressure chamber, and the heat generation A resistor is provided in the pressure chamber via an insulating layer.

  According to the droplet discharge head described in claim 9, in the droplet discharge head described in claim 1, the heating resistor is provided so as to be in contact with the pressure chamber filled with the liquid. For this reason, the heat energy by heat_generation | fever of a heating resistor can be efficiently transmitted to the liquid in a pressure chamber, and the liquid in a pressure chamber can be heated efficiently.

  According to a droplet discharge head according to claim 10, in the droplet discharge head according to claim 1, the piezoelectric element substrate includes a plurality of the piezoelectric elements, and a plurality of the heating resistors are the piezoelectric elements. It is characterized by being provided corresponding to each.

  According to the droplet discharge head of claim 10, since the heating resistor is provided corresponding to each of the plurality of piezoelectric elements, the heating of the piezoelectric element and the periphery of the piezoelectric element by the heat generation of the heating resistor is performed. This can be done for each piezoelectric element.

  According to the droplet discharge head of claim 11, in the droplet discharge head of claim 10, the plurality of heating resistor driving means for driving each of the plurality of heating resistors, and the plurality of piezoelectric elements A temperature measuring means for measuring each environmental temperature, a driving condition for obtaining a droplet discharge condition identical to a predetermined temperature condition, a storage means for storing a relationship between the environmental temperature in advance, and the driving condition; The heating resistors corresponding to each of the plurality of piezoelectric elements so that each of the plurality of heating resistors is driven under a driving condition corresponding to the environmental temperature measured by the temperature measuring unit based on the relationship with the environmental temperature. Control means for controlling each of the body drive means.

  The heating resistor driving means of the droplet discharge head according to claim 11 drives each of the plurality of heating resistors. When the environmental temperature of each of the plurality of piezoelectric elements is measured by the temperature measurement unit, the control unit determines that each of the plurality of heating resistors is a temperature measurement unit based on the relationship between the driving condition and the temperature stored in the storage unit. The heating resistor driving means corresponding to each of the plurality of piezoelectric elements is controlled so that the driving is performed under the driving conditions corresponding to the environmental temperature measured by the above.

  According to the droplet discharge head of the eleventh aspect, the heating resistor corresponding to each piezoelectric element is driven according to the measurement result of the environmental temperature of each of the plurality of piezoelectric elements provided in the droplet discharge head. Therefore, the temperature of the droplet can be adjusted for each individual piezoelectric element.

  According to a droplet discharge head according to a twelfth aspect, in the droplet discharge head according to the first aspect, the piezoelectric element substrate is disposed between the piezoelectric bodies and the heating resistor drives the heating resistor. A body driving means, a heating resistor driving electrode connected to the heating resistor and the heating resistor driving means, a connection electrode connecting the heating resistor and the first electrode, and the first electrical wiring Piezoelectric element driving means that is connected and disposed between the piezoelectric bodies and drives the piezoelectric element; and third electric wiring that connects the piezoelectric element driving means and the first electrode.

  According to the droplet discharge head of claim 12, the piezoelectric element, the piezoelectric element driving means for driving the piezoelectric element, the heating resistor, the heating resistor driving means, the heating resistor driving electrode, and the connection electrode A third electrical wiring, a third electrical wiring, a second electrode, a first electrical wiring, a second electrical wiring, and a first electrode are provided on the same piezoelectric element substrate. Yes. Therefore, it is possible to provide a droplet discharge head that can efficiently heat the liquid around the piezoelectric element and discharge the droplet stably with a simple configuration.

  According to a droplet discharge head according to a thirteenth aspect, in the droplet discharge head according to the first aspect, the first electric wiring is formed in a region where the piezoelectric body is formed in a plan view. . For this reason, it is possible to reduce the size of the droplet discharge head.

  A droplet discharge device according to a fourteenth aspect includes the droplet discharge head according to any one of the first to thirteenth aspects. Therefore, it is possible to provide a droplet discharge device that can efficiently heat the liquid around the piezoelectric element with a simple configuration and discharge the droplet stably.

  According to the droplet discharge head and the droplet discharge device of the present invention, there is provided a droplet discharge head and a droplet discharge device that can efficiently heat a liquid around a piezoelectric element with a simple configuration and can stably discharge a droplet. Can be provided.

(First embodiment)
DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below in detail based on the embodiments shown in the drawings. Note that the ink jet recording apparatus 10 will be described as an example of the droplet discharge apparatus. Therefore, the liquid will be described as ink N, and the droplet discharge head will be described as an inkjet recording head 32. The recording medium will be described as recording paper P. In each figure, when an arrow UP and an arrow DO are indicated, the direction indicated by the arrow UP is the upward direction, and the direction indicated by the arrow DO is the downward direction. In addition, the same code | symbol is provided to the member which has the substantially same function throughout all the drawings, and the overlapping description may be abbreviate | omitted.

  As shown in FIG. 1, the ink jet recording apparatus 10 includes a paper supply unit 12 that sends out the recording paper P, a registration adjustment unit 14 that controls the posture of the recording paper P, and forms an image on the recording paper P by ejecting ink droplets. The recording head unit 16 and the recording unit 20 including the maintenance unit 18 that performs maintenance of the recording head unit 16 and the discharge unit 22 that discharges the recording paper P on which the image is formed by the recording unit 20 are basically configured. .

  The paper supply unit 12 includes a paper supply unit 24 that stores the recording paper P and a conveyance device 26 that takes out the paper from the paper supply unit 24 one by one and conveys it to the registration adjustment unit 14.

  The registration adjusting unit 14 includes a loop forming unit 28 and a guide member 29 that controls the posture of the recording paper P. The recording paper P passes through this portion, and uses the stiffness to skew. Is corrected, and the conveyance timing is controlled and supplied to the recording unit 20.

  The discharge unit 22 stores the recording paper P on which an image is formed by the recording unit 20 in the paper discharge unit 25 via the paper discharge belt 23.

  Between the recording head unit 16 and the maintenance unit 18, a paper transport path 27 through which the recording paper P is transported is formed (the paper transport direction is indicated by an arrow PF). The paper conveyance path 27 includes a star wheel 17 and a conveyance roll 19, and conveys the recording paper P between the star wheel 17 and the conveyance roll 19 continuously (without stopping). Then, ink droplets are ejected from the recording head unit 16 to the recording paper P, and an image is formed on the recording paper P.

  The maintenance unit 18 includes a maintenance device 21 disposed to face the ink jet recording unit 30 (ink jet recording head 32), and performs capping and wiping on the ink jet recording head 32 (ink jet recording head 32), and further a dummy. Processes jets and vacuums.

  As shown in FIG. 2, each inkjet recording unit 30 includes a support member 34 disposed in a direction intersecting (orthogonal) with the sheet conveyance direction indicated by the arrow PF, and a plurality of inkjet recording heads are provided on the support member 34. 32 is attached. In the inkjet recording head 32, a plurality of nozzles 36 are formed in a matrix, and the nozzles 36 are arranged in parallel in the width direction of the recording paper P at a constant pitch as the entire inkjet recording unit 30.

  An image is recorded on the recording paper P by ejecting ink droplets from the nozzles 36 onto the recording paper P that is continuously transported through the paper transporting path 27. For example, in order to record a so-called full-color image, at least four inkjet recording units 30 are arranged corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K). Has been.

  As shown in FIG. 3, the print area width by the nozzles 36 of each ink jet recording unit 30 is longer than the maximum paper width PW of the recording paper P on which image recording by the ink jet recording apparatus 10 is assumed. It is possible to record an image over the entire width of the recording paper P without moving the inkjet recording unit 30 in the paper width direction.

  Here, the print area width is basically the largest of the recording areas obtained by subtracting the margins not to be printed from both ends of the recording paper P, but is generally larger than the maximum paper width PW to be printed. ing. As a result, the recording paper P can be transported while being inclined (skewed) by a predetermined angle with respect to the transport direction and borderless printing.

  Next, a first embodiment of the inkjet recording head 32 will be described. FIG. 17 is a schematic plan view schematically showing the configuration of the ink jet recording head 32. FIG. 4 is a partially enlarged plan view showing the periphery of a piezoelectric element (details will be described later) in the inkjet recording head 32. FIG. 5 is a schematic cross-sectional view showing the main part of the ink jet recording head 32 which is partially taken out, and shows a part of the A-A ′ cross-sectional view of FIG. 17. In FIG. 5, the state in which the inkjet recording head 32 is turned upside down, that is, the side on which the nozzles 36 for ejecting ink droplets are formed is shown as the upper side.

As shown in FIG. 17, the inkjet recording head 32, a plurality of the piezoelectric elements 60 ₁ to the piezoelectric element 60 _n, the details will be described later provided on the piezoelectric elements 60 ₁ to the piezoelectric element per 60 _n heating resistors 37 ₁ to the heating resistor and 37 _n, ~ piezoelectric element control circuit 50A ₁ for driving 60 _n respectively the piezoelectric elements 60 ₁ to the piezoelectric element provided on the piezoelectric elements 60 ₁ to the piezoelectric element per 60 _n piezoelectric control circuit 50A and _n, the heating resistor control circuits 50B _1-heating resistor control circuit 50B _n for driving the heat-generating resistor 37 ₁ to the heating resistors 37 _n each are provided.

The piezoelectric elements 60 ₁ to 60 _n are collectively referred to as the piezoelectric element 60, and the piezoelectric element control circuits 50A ₁ to 50A _n are collectively referred to as the piezoelectric element control circuit 50A. Will be described. Further, when the heating resistors 37 ₁ to 37 _n are collectively referred to as the heating resistor 37, the heating resistors control circuit 50 B ₁ to the heating resistor control circuit 50 _Bn are collectively referred to as heat generation. The resistor control circuit 50B will be described.

  Thus, the inkjet recording head 32 is provided with one piezoelectric element control circuit 50 </ b> A and one heating resistor control circuit 50 </ b> B for each piezoelectric element 60.

In addition, each of these piezoelectric element control circuits 50A ₁ to 50A _{n and} each of the heating resistor control circuit 50B ₁ to the heating resistor control circuit 50B _n are provided between the piezoelectric element 60 and the piezoelectric element 60. It is arranged.

  In the following description, one piezoelectric element control circuit 50A and one heating resistor control circuit 50B provided corresponding to each piezoelectric element 60 will be collectively referred to as a drive element 50.

As described above, each of the piezoelectric elements 60 ₁ to 60 _n is provided with the drive element 50 (drive element 50 ₁ to drive element 50 _n ). Each of the drive elements 50 ₁ to 50 _n is connected to a controller 99 (described later in detail) that controls the inkjet recording head 32 so as to be able to send and receive signals.

  As shown in FIG. 5, which is a schematic cross-sectional view taken along the line AA ′ of FIG. 17, the inkjet recording head 32 is configured by laminating and arranging a flow path substrate 76, a piezoelectric element substrate 71, and an ink pool member 73. .

First, the configuration of the piezoelectric element substrate 71 will be described.
The piezoelectric element substrate 71 includes a piezoelectric element 60, a heating resistor 37, a silicon substrate 40, a vibration plate 70, and a drive element 50.

  The piezoelectric element 60 is configured by laminating a PZT film 62 as a piezoelectric body, an upper electrode 64 as a first electrode, and a TEOS film 66 in this order on a lower electrode 58 as a second electrode.

  The lower electrode 58 functions as one polarity electrode of the PZT film 62, and the upper electrode 64 functions as the other polarity electrode of the PZT film 62.

  A wiring protective layer 74 is laminated on a partial region of the TEOS film 66 via a metal wiring 72 as a third electric wiring connected to the upper electrode 64. The TEOS film 66 functions as an insulating film that avoids a short circuit with the PZT (piezoelectric) film 62 of the piezoelectric element 60 and also as a moisture-resistant protective film of the PZT film 62.

The heating resistor 37 is a resistor that generates heat when a driving voltage is applied, and is stacked on the piezoelectric element 60.
The thickness of the heating resistor 37 may be any thickness that can heat the piezoelectric element 60 and ink at least in the vicinity of the piezoelectric element 60 in consideration of characteristics such as electrical resistance of the material constituting the heating resistor 37. It is preferable that the thickness be such that the deformation of the PZT film 62 is not hindered.

  The shape of the heating resistor 37 is not limited as long as the heating resistor 37 is provided in a region where the piezoelectric element 60 is formed in a plan view, but preferably the surface of the piezoelectric element 60 as shown in FIG. Is preferably provided in a meandering manner.

  Thus, by providing the heating resistor 37 in a meandering manner, the connection electrode 33 (described later in detail) connected to one end of the heating resistor 37 and the heating resistor drive electrode 39 (described later in detail) connected to the other end. When the drive voltage is applied to the heating resistor 37 via the heating resistor 37, the heating resistor 37 can efficiently generate heat.

  As shown in FIG. 6, the heating resistor 37 is formed by laminating a self-oxidation film 37B on the heating resistor layer 37A. The heating resistor 37 includes Ta silicide. As the silicide of Ta constituting the heating resistor 37, TaSixNy, TaSixOy, or the like can be used. Among these, it is preferable to use TaSiO because the volume resistivity can be increased and efficient heat generation can be performed.

  The self-oxidized film 37B is formed by self-oxidizing the surface of the heating resistor 37 made of Ta silicide. Since the self-oxidized film 37B thus formed is insulative, the self-oxidized film 37B can prevent the heating resistor layer 37A from coming into direct contact with the ink.

  Further, since the self-oxidation film 37B formed by self-oxidation is known to be very thin (for example, a film thickness of 0.01 μm), it is compared with the case where an insulating layer is separately provided on the heating resistor 37. The heat loss of the heating resistor 37 can be suppressed, the piezoelectric element 60 and the periphery of the piezoelectric element 60 can be efficiently heated without lowering the thermal energy, and the ink can be efficiently warmed.

  One end of the heating resistor 37 in the direction orthogonal to the stacking direction is connected to the metal wiring 72 connected to the upper electrode 64 via the connection electrode 33. The other end of the heating resistor 37 in the direction orthogonal to the stacking direction is electrically connected to the heating resistor drive wiring 43 via the heating resistor drive electrode 39. The heating resistor drive wiring 43 is electrically connected to the heating resistor control circuit 50B.

  The diaphragm 70 includes a tetraethoxysilane film (hereinafter referred to as “TEOS film”) 54 as a first layer and a local oxidation of silicon film (hereinafter referred to as a second layer) formed by a chemical vapor deposition (CVD) method. 44 (referred to as “LOCOS film”), which has elasticity at least in the vertical direction, and is configured to bend and deform in the vertical direction when a voltage is applied to the piezoelectric element 60.

  An electrical wiring 52 as a first electrical wiring is provided inside the diaphragm 70, that is, between the TEOS film 54 and the LOCOS film 44. In addition, the diaphragm 70 has an electrical connection through hole 94 for electrically connecting the electrical wiring 52 and the lower electrode 58, and the metal wiring 72 (upper electrode 64) and the drive element 50, and an electrical connection through hole, respectively. 96 is formed. Further, the diaphragm 70 is provided with a heating resistor drive wiring 43 and an electrical connection through hole 97 for electrically connecting the drive element 50.

  A second electrical wiring 56 is formed by filling the through hole 94 for electrical connection with a high melting point metal having a melting point of 600 ° C. or higher, for example, tungsten, and the electrical wiring 52 and the lower electrode 58 are electrically connected. Also in the electrical connection through hole 96, the electrical wiring 68 formed by filling tungsten, the connection electrode 33, the metal wiring 72 (upper electrode 64), and the piezoelectric element control circuit 50A are electrically connected. Yes.

  Similarly, one heating resistor control circuit 50B and a heating resistor drive are formed by filling the electrical connection through-hole 97 with a high melting point metal having a melting point of 600 ° C. or more, for example, tungsten to form the electrical wiring 69. The wiring 43 is electrically connected.

Next, the configuration of the ink pool member 73 will be described.
An ink pool member 73 is provided on the lower surface side of the piezoelectric element substrate 71, specifically, on the lower surface side of the silicon substrate 40. The ink pool member 73 includes a manifold 86 made of a material having ink resistance. The manifold 86 is bonded to the lower surface side of the silicon substrate 40, and the manifold 86 is bonded to the lower surface side of the silicon substrate 40, thereby providing a predetermined shape and volume between the manifold 86 and the diaphragm 70. An ink pool chamber 80 is formed.

The manifold 86 has an ink supply port (not shown) connected to an ink tank (not shown) that stores the ink N at a predetermined location, and the ink N injected from the ink supply port is stored in the ink pool. It is stored in the chamber 80. Note that an air damper 84 is provided in the manifold 86 so that vibration due to injection does not affect the other nozzles 36 (in order to prevent crosstalk).
Further, an ink filter 88 is installed in the ink pool chamber 80 in order to remove dust in the ink N.

Next, the configuration of the flow path substrate 76 will be described.
A flow path substrate 76 is connected to the upper surface side of the piezoelectric element substrate 71. A nozzle 36 for discharging ink N is formed on the flow path substrate 76. By bonding the flow path substrate 76 to the upper surface side of the piezoelectric element substrate 71, a pressure chamber 82 is formed between the piezoelectric element substrate 71 and the flow path substrate 76. Further, as shown in FIG. 5, the piezoelectric element substrate 71 is formed with an ink supply path 90 (ink supply through-hole 92) for communicating the pressure chamber 82 and the ink pool chamber 80.

  For this reason, in the ink jet recording head 32, a flow path for ink N is formed to communicate from the ink pool chamber 80 to the ink supply path 90, the pressure chamber 82, and the nozzle 36, and an ink supply port (not shown). The ink N injected and stored in the ink pool chamber 80 is filled into the pressure chamber 82 via the ink supply path 90. When a drive voltage is applied to the piezoelectric element 60 through the upper electrode 64 and the lower electrode 58, the pressure chamber 82 is expanded or compressed by bending and deforming the diaphragm 70 along with the deformation of the piezoelectric element 60. As a result, a volume change occurs in the pressure chamber 82, and a pressure wave is generated in the pressure chamber 82. By the action of the pressure wave, the ink N moves and ink droplets are ejected from the inside of the ink jet recording head 32 to the outside via the nozzle 36.

  The ink pool chamber 80 and the pressure chamber 82 are configured not to exist on the same horizontal plane. Thereby, the pressure chambers 82 can be arranged in a state of being close to each other, and the nozzles 36 can be arranged in a matrix at high density. In addition, a flexible printed circuit board (hereinafter referred to as “FPC”) 100 is connected to the electrical wiring 52 via bumps 38 (see FIG. 4).

  Next, the manufacturing process of the ink jet recording head 32 of the first embodiment will be described in detail with reference to FIGS.

  First, as shown in FIG. 7A, the driving element 50 is formed on the silicon substrate 40. As the manufacturing method of the drive element 50, a generally known manufacturing method is used.

That is, a LOCOS film 44 (film thickness: 0.7 μm) is deposited on the silicon substrate 40 in a region excluding the impurity (N ⁺ ) diffusion region 42, and the impurity (N ⁺ ) diffusion region 42 is formed on the silicon substrate 40. The polysilicon 46 is laminated. Then, a boron-phosphorus-silicon glass film 48 (hereinafter referred to as “BPSG film”, film thickness: 0.5 μm) is deposited on the impurity (N ⁺ ) diffusion region 42, the LOCOS film 44, and the polysilicon 46.

  Next, an electric wiring 52 (film thickness: 0.5 μm) made of a high-temperature resistant metal such as Ta, Ti, W, Pt is deposited as an individual wiring on the upper surface of the BPSG film 48 so as to correspond to each piezoelectric element 60. (See FIG. 4). An ink supply through-hole 92 for forming the ink supply path 90 is formed at predetermined positions of the LOCOS film 44, the BPSG film 48, and the electric wiring 52 for each process. Further, the film formation range of the electric wiring 52 is set to a predetermined position that does not reach the ink supply through-hole 92.

  Thereafter, as shown in FIG. 7B, a TEOS film 54 (film thickness: 3.3 μm) is deposited. Thereby, the thickness of the diaphragm 70 constituted by the LOCOS film 44, the BPSG film 48, and the TEOS film 54 is, for example, 5 μm to 7 μm. At this time, the end portion 52A (see FIG. 7A) of the electric wiring 52 facing the ink supply through-hole 92 is covered with the TEOS film 54 so that the electric wiring 52 is not exposed to the ink supply through-hole 92. To. Also, an electrical connection through-hole 94 for electrical connection between the electrical wiring 52 and the lower electrode 58, an electrical connection through-hole 96 for electrical connection between the drive element 50 and the upper electrode 64, and heating resistor driving An electrical connection through hole 97 for electrically connecting the wiring 43 and the drive element 50 is formed in the TEOS film 54.

  Here, the film laminated as the vibration plate 70 may be a film other than the TEOS film 54 as long as it has low stress and does not generate cracks even when deposited several μm or more. In order to relieve stress, a film to which boron (B), phosphorus (P), germanium (Ge), or the like is added may be used. When the diaphragm 70 is formed, if the formation area of the piezoelectric element 60 is uneven, a flat surface with a surface roughness (Ra) of 1 μm or less is obtained using a flattening technique such as polishing or etchback. To do.

  After that, as shown in FIG. 7C, the second electrical wiring 56, the electrical connection through hole 94, the electrical connection through port 96, and the electrical connection through port 97 are filled with tungsten. The electric wiring 68 and the electric wiring 69 are formed, and a Ti film (film thickness: 10 nm) and a Pt film (film thickness: 250 nm) to be the lower electrode 58 are continuously deposited on the TEOS film 54 by sputtering. The film deposition range of the lower electrode 58 is set to a predetermined position that does not reach the ink supply through hole 92 and the electrical connection through hole 96. Further, filling of the through hole 94 for electrical connection, the through hole 96 for electrical connection, and the through hole 97 for electrical connection with tungsten is performed by depositing tungsten after forming Ti / TiN (not shown) as a barrier layer, and thereafter It is performed by polishing.

Here, Pt is used as the lower electrode 58. However, even if another metal such as Ir, Au, Ru, which has high affinity with the PZT film 62 constituting the piezoelectric element 60 and has heat resistance, is used. I do not care. In order to improve the crystal orientation and adhesion of the PZT film 62 to be formed later, an orientation control film (STO, BTO, etc.) or a Ti, TiO ₂ film or the like may be deposited as an adhesion layer.

  Thereafter, as shown in FIG. 8D, a PZT film 62 (film thickness: 5 μm) is deposited by sputtering, and subsequently, a Pt film (film thickness: 0.5 μm) as the upper electrode 64 is deposited. To do. Then, the PZT film 62 and the upper electrode 64 are patterned by a photolithography process and an etching process. Note that the PZT film 62 as a piezoelectric body may be deposited by other means such as a sol-gel method, an MOCVD method, or an AD method. Further, although Pt is used as the upper electrode 64 here, another metal such as Ir, Au, or Ru having high affinity with the PZT film 62 constituting the piezoelectric element 60 and heat resistance may be used. I do not care.

  Thus, the piezoelectric element 60 is formed. The piezoelectric element 60 is formed above the layer where the electric wiring 52 is formed. That is, the electric wiring 52 is formed in a layer below the piezoelectric element 60 and is formed as an individual wiring in a region where the piezoelectric element 60 is formed in a plan view. The piezoelectric element 60 is formed for each drive element 50 and is configured to correspond one-to-one. That is, the same number of piezoelectric elements 60 and drive elements 50 are provided so that one piezoelectric element 60 is driven by one drive element 50 (piezoelectric element control circuit 50A).

  Thereafter, as shown in FIG. 8E, a TEOS film 66 as an insulating protective film is deposited on the lower electrode 58, the PZT film 62, and the upper electrode 64. That is, a TEOS film 66 (film thickness: 0.5 μm) is deposited as an insulating film that avoids a short circuit with the PZT film 62 and as a moisture-resistant protective film for the PZT film 62. At this time, the end 58A of the lower electrode 58 facing the ink supply through-hole 92 and the end 58A of the lower electrode 58 facing the electrical connection through-hole 96 are covered with the TEOS film 66, and the lower electrode 58 is covered with the ink. The supply through-hole 92, the electrical connection through-hole 96, and the electrical connection through-hole 97 are not exposed. Further, a contact hole 66 A for connecting a metal wiring 72 (described later) to the upper electrode 64 is formed in the TEOS film 66.

  Thereafter, as shown in FIG. 9 (F), the TEOS film 66 continues from one end portion in the direction orthogonal to the stacking direction of the piezoelectric elements 60 through the side surface of the piezoelectric element 60 continuous to the one end portion. A metal wiring 72 (film thickness: 1.0 μm) is deposited so as to fill and cover the contact hole 66A in the direction, and is connected to the upper electrode 64 through the contact hole 66A. The electrical wiring 68 filled is also connected. The metal wiring 72 may be made of a material such as Al or an Al alloy. Then, a wiring protective layer 74 is deposited on the upper surface of the metal wiring 72.

  Further, a heating resistor driving wiring 43 (film thickness: 0.5 μm) is deposited on a region continuous with the side surface continuous with the other end portion in the direction orthogonal to the stacking direction of the piezoelectric elements 60 on the upper surface of the TEOS film 66. To do. A wiring protective layer 74 is also deposited on the upper surface of the heating resistor driving wiring 43.

  Note that the heating resistor driving for electrically connecting the heating resistor driving wiring 43 and the heating resistor 37 is formed in the region of the wiring protective layer 74 formed on the upper surface of the heating resistor driving wiring 43. A contact hole 74A for forming the electrode 39 is formed in advance. Further, a contact hole 74B for forming a connection electrode 33 for connecting the upper electrode 64 and one end of the heating resistor 37 is formed in a region of the wiring protective layer 74 deposited on the upper surface of the metal wiring 72. Is formed.

  Each of the contact hole 74B and the contact hole 74A is filled with tungsten, so that the connection electrode 33 and the heating resistor drive electrode 39 are formed.

  The wiring protective layer 74 may have an oxide film, a nitride film, a resin film such as polyimide, or a two-layer structure of a metal film and an insulating film. Here, a film having a two-layer structure of a SiN film (film thickness: 0.2 μm) and a Ta film (film thickness: 0.5 μm) is used as the wiring protective layer 74. In addition, the voltage application necessary for driving the piezoelectric element 60 may be performed on the diaphragm 70 side on the GND (ground) side or on the + (plus) side.

  Next, as shown in FIG. 10 (G), a heating resistor 37 made of TaSiO is deposited to a thickness of 0.1 μm (sputtering) on the upper surface of the wiring protective layer 74 so as to cover at least the upper surface of the piezoelectric element 60. Then, masking is performed with a resist (not shown), and etching is performed with a fluorine-based gas, thereby patterning to a desired size. Thereafter, the resist is removed. Next, heat treatment is performed at a temperature of 450 ° C. for several tens of minutes in an oxygen atmosphere. As a result, an oxide film (self-oxidized film 37B) (film thickness of 0.01 μm) is formed on the surface of the heating resistor 37.

  With this process, one end of the heating resistor 37 is connected to the metal wiring 72 connected to the upper electrode 64 via the connection electrode 33, and the other end is connected to the heating resistor driving wiring 43 via the heating resistor driving electrode 39. It can be set as the structure electrically connected to.

  Thereafter, an ink pool chamber 80 is formed as shown in FIG. That is, the opening 40A is formed in a predetermined region on the back surface of the silicon substrate 40 by a photolithography process and an etching process. And it connects with the through-hole 92 for ink supply previously formed.

  Subsequently, as shown in FIG. 12H, in order to flatten the wall surface of the pressure chamber 82, first, a resin layer is spin-coated as a flow path substrate 76 such as polyimide and patterned. The film thickness of this resin layer may be about 20 μm. Further, as shown in FIG. 12I, a pressure chamber forming resin layer 78 is spin-coated and patterned. Thereby, the shape of the pressure chamber 82 is patterned into a desired shape and volume. Here, the thickness of the resin layer 78 is 40 μm.

  Thereafter, as shown in FIG. 13J, a resin layer is further spin-coated as a flow path substrate 76, and patterning for forming the nozzles 36 is performed. In addition, the film thickness of the resin layer as the flow path substrate 76 at this time is 20 μm. Then, as shown in FIG. 13K, the resin layer 78 is removed with an organic solvent. As a result, the pressure chamber 82 is formed, and the ink pool chamber 80 and the pressure chamber 82 are connected by the ink supply path 90 (ink supply through-hole 92).

  Subsequently, as shown in FIG. 14L, the FPC 100 for taking out a signal line to the outside is connected to the electric wiring 52 through the bump 38.

  Thereafter, as shown in FIG. 15M, a manifold 86 for supplying ink is bonded to the silicon substrate 40. Here, an ink filter 88 for removing dust in the ink N is installed in the opening portion of the ink pool chamber 80 before the manifold 86 is joined. The ink filter 88 is not particularly limited as long as it has a function of filtering dust, such as a resin filter and a SUS filter, and has a filter diameter that does not inhibit the flow of the ink N.

  Further, here, an air damper 84 is provided in the manifold 86 so that vibration due to injection does not affect the other nozzles 36 (in order to prevent crosstalk). That is, a resin film (air damper 84) of 20 μm or less is formed on the manifold 86 which is a resin molded product. Thus, the ink jet recording head 32 of the first embodiment in which the piezoelectric element 60 faces (facing) the pressure chamber 82 is completed, and the ink N is placed in the ink pool chamber 80 and the pressure chamber 82 as shown in FIG. Filling is possible.

Next, the electrical configuration of the inkjet recording head 32 will be described.
As shown in FIG. 16 and FIG. 17 described above, the inkjet recording apparatus 10 includes a controller 99 and a plurality of drive elements 50 ₁ to 50 _n connected to the controller 99 so as to be able to exchange signals. It is configured to include.

  The controller 99 includes a control unit 99A, a memory 99B, a pulse generation circuit 99C, and a data acquisition unit 99D. The memory 99B, the pulse generation circuit 99C, and the data acquisition unit 99D are connected to the control unit 99A so as to exchange signals.

  The memory 99B associates in advance drive condition information indicating a drive condition under which the same ink discharge condition as the ink discharge condition under a predetermined environmental temperature is obtained, and environmental temperature information indicating the environmental temperature of the piezoelectric element 60. As well as various data.

  The ink discharge conditions indicate the amount of ink droplets discharged from the nozzles 36 and the ink droplet discharge speed. The driving condition is a driving condition for driving the heating resistor 37. For example, when the heating resistor 37 is driven based on a pulse signal, the driving condition includes a predetermined pulse width and driving. A pulse signal indicated by a voltage value and the number of pulses can be given.

  The drive conditions are determined in advance according to, for example, the material of the heating resistor 37, the resistance value, the structure of the ink jet recording head 32, and the like so that the same conditions can be obtained at different environmental temperatures. The memory 99B may be stored in association with the environmental temperature information indicating the corresponding environmental temperature. For example, as drive conditions, a pulse having a pulse width of 10 μsec and a drive voltage of 3.3 V may be determined according to the environmental temperature by determining the number of pulses according to the environmental temperature.

  In addition, the above-mentioned driving condition information and the difference between the environmental temperature of the piezoelectric element 60 and the predetermined environmental temperature are stored in advance in the memory 99B, and the measurement was performed when the driving condition corresponding to the environmental temperature was determined. The driving condition may be determined based on a calculation result obtained by calculating a difference between the environmental temperature and a predetermined environmental temperature.

  The pulse generation circuit 99C generates a pulse signal corresponding to the drive condition read from the memory 99B under the control of the control unit 99A, and outputs the pulse signal to the heating resistor control circuit 50B. The pulse generation circuit 99C similarly generates a pulse signal as a drive signal for driving the piezoelectric element 60 based on the image data input from the data acquisition unit 99D, and outputs the pulse signal to the piezoelectric element drive circuit 50A. .

  The data acquisition unit 99D acquires image data, various data, various signals, and the like from a control unit (not shown) that controls the main body of the inkjet recording apparatus 10. The image data is data obtained by converting recorded image data of an image recorded by the inkjet recording apparatus 10 into data that can be analyzed by the inkjet recording head 32.

  The piezoelectric element control circuit 50 </ b> A includes a temperature detection circuit 106 and a drive circuit 108 for driving the piezoelectric element 60, and is connected to the piezoelectric element 60 through the driver 102 so as to exchange signals. .

  The temperature detection circuit 106 detects the temperature of the piezoelectric element 60. That is, by detecting the temperature of the piezoelectric element 60, the temperature of the piezoelectric element 60 and the ink around the piezoelectric element 60 can be detected.

  As this temperature detection method, the PZT film (piezoelectric body) 62 constituting the piezoelectric element 60 has a characteristic that the capacitance changes in accordance with a temperature change, and therefore, a method using this characteristic can be mentioned. Specifically, as shown in FIG. 16, a detection unit 103 that detects the capacitance of the PZT film 62 is provided, and temperature information of the piezoelectric element 60 corresponding to the capacitance of the PZT film 62 is associated in advance. There is a method of storing the temperature in the temperature detection circuit 106 and detecting the temperature of the temperature information corresponding to the capacitance detected from the detection unit 103 as the temperature of the piezoelectric element 60.

  As a method for detecting the temperature of the piezoelectric element 60 and the surroundings of the piezoelectric element 60, a thermistor or the like for detecting the temperature is provided for each of the plurality of piezoelectric elements 60 or in each pressure chamber 82. And the temperature detection circuit 106 detects the temperature of the piezoelectric element 60 and the surroundings of the piezoelectric element 60 based on a signal indicating the temperature detection result input from the thermistor. Good.

Further, as a method of detecting the temperature of the piezoelectric element 60 and the surroundings of the piezoelectric element 60, the resistance value of the heating resistor 37 itself also changes due to temperature fluctuation, and the heating resistor 37 is laminated on the piezoelectric element 60. In addition, a detection unit (not shown) for previously storing resistance value information corresponding to the temperature information of the heating resistor 37 in association with the temperature detection circuit 106 and detecting a change in the resistance value of the heating resistor 37 is provided. The detection unit and the temperature detection circuit 106 are connected so as to be able to exchange signals, and the temperature of the temperature information corresponding to the resistance value of the heating resistor 37 detected by the detection unit is set in the vicinity of the piezoelectric element 60 and the piezoelectric element 60. A method for detecting the temperature may be used.
In this case, from the viewpoint of increasing the temperature detection accuracy, it is preferable that the heating resistor 37 is provided in a meandering manner as shown in FIG.

The heating resistor drive circuit 50B includes a shift register 110, a latch 112, and a decoder 114. Although not shown, the input end of the shift register 110 is connected to the controller 99, and the output end is connected to the latch 112.
The output terminal of the shift register 110 is connected to a latch for driving the heating resistor 37 corresponding, and a latch for driving the heating resistor provided adjacent to the heat generating resistor 37 _1, the Has been.
The input end of the latch 112 is connected to the shift register 110, and the output end is connected to the decoder 114. One of the input terminals of the decoder is connected to the latch 112 and the other is connected to the controller 99. The output terminal of the decoder is connected to the heating resistor 37 via the driver 104.

  Next, the operation of temperature control in the inkjet recording head 32 will be described.

  In the control unit 99A, the processing routine shown in FIG. 18 is executed every predetermined time, and the process proceeds to Step 100, where image data is acquired from a control unit (not shown) for controlling each unit of the inkjet recording apparatus 10. This routine is terminated if the result is negative, and the process proceeds to step 104 if the result is affirmative.

  In step 104, an image forming process for forming an image on the recording paper P is started by discharging ink from each nozzle 36 based on the acquired image data.

  In the next step 106, counting of an internal counter (not shown) is started, and in the next step 108, a negative determination is repeated until a predetermined time elapses.

In step 110, the temperature measurement result of each of the piezoelectric elements 60 _{1 to} 60 _n is read. Process of step 110, by reading the temperature measurement result inputted from the piezoelectric element control circuit _50A 1 _{~50A n} each of the temperature detection circuit 106 can be read.

  In the next step 112, driving condition information corresponding to the temperature information indicating the temperature measurement result read in step 110 is read from the memory 99B.

In the next step 114, as the heat generating resistor ₃₇ 1 to 37 _n respectively corresponding to the piezoelectric elements ₆₀ 1 to 60 _n in the drive condition information read in step 112 is driven, the driving elements 50 ₁ to drive element 50 _n each is controlled.

Specifically, the process of step 114 is controlled to generate a drive pulse signal in the pulse generation circuit 99C based on the drive condition information for each of the piezoelectric elements 60 _{1 to} 60 _n read from the memory 99B. Then, the heating resistor control circuit _50B 1 _{~50B n} respectively corresponding to the piezoelectric elements ₆₀ 1 to 60 _n respectively, and outputs a driving condition signal including a pulse signal corresponding to the driving condition information.

  The drive condition signal includes a pulse signal generated by the pulse generation circuit 99C, a clock signal, a latch signal that can hold data for each latch 112, and an on / off signal that indicates whether driving is performed. It is configured to include.

In each of the heating resistor control circuits 50B _{1 to} 50B _n to which the drive condition signal has been input, the latch register 112 is started to input a latch signal capable of holding data, and at the same time, an ON / OFF signal is sent to the shift register 110. The serial input is performed in synchronization with the clock signal. As a result, the ON / OFF signals for all the heating resistors 37 _{1 to} 37 _n are latched (temporarily stored and held) in each latch 112.

  Further, when the pulse signal generated by the pulse generation circuit 99C is output to the decoder 114, the decoder 114 calculates the logical sum of the output from the latch 112 and the pulse signal input to the decoder 114. The heating resistor 37 is driven through the driver 104 for a time defined by the pulse width defined by the drive pulse signal and the number of times defined by the number of pulses defined by the drive pulse signal.

Through the process of step 114, the driving condition corresponding to the temperature information of the measured temperature, the heating resistors 37 ₁ to 37 _n are independently driven. Since the heating resistors 37 _{1 to} 37 _n are driven and the heating resistors 37 _{1 to} 37 _n generate heat, the periphery of each of the heating resistors 37 _{1 to} 37 _n is heated. Can be individually heated.

  In the next step 116, after resetting the timer count started in step 106, the process proceeds to step 118, where it is determined whether or not all image formation has been completed for the image data acquired via the data acquisition unit 99D. When the result is negative, the routine returns to step 106, and when the result is positive, this routine is terminated.

  As described above, according to the ink jet recording head 32 of the present invention, since the heating resistor 37 is integrally provided on the piezoelectric element substrate 71, the ink jet recording head 32 in the ink jet recording head 32 can be easily formed with a simple configuration. The ink can be heated, and the increase in size of the ink jet recording head 32 due to the provision of the heating resistor 37 can be suppressed.

Further, the heating resistor 37, because it is arranged separately for each of the piezoelectric elements ₆₀ 1 to 60 _n respectively, to efficiently heat the pressure chamber 82 contiguous to the piezoelectric elements ₆₀ 1 to 60 _n respectively be able to. In addition, since the plurality of piezoelectric elements 60 _{1 to} 60 _n and the pressure chambers 82 continuing to each of the piezoelectric elements 60 _{1 to} 60 _n can be individually controlled by heating, a plurality of elements in the inkjet recording head 32 can be controlled. The ink temperature in the pressure chamber 82 can be adjusted quickly and uniformly. For this reason, the viscosity of the ink droplets discharged from each of the plurality of nozzles 36 can be made uniform. Therefore, when the same drive signal is applied to each piezoelectric element 60, it is possible to suppress variations in the discharge speed and discharge amount of the ink discharged from each of the plurality of nozzles 36, and to suppress deterioration in image quality. Can do.

  In the processing routine shown in FIG. 18, the control unit 99A measures the temperature of the ink around each piezoelectric element 60 every predetermined time after starting ink ejection (image formation) based on the acquired image data. Although the case where the heating resistor 37 is driven based on the measurement result has been described, the timing for driving the heating resistor 37 is not limited to such timing.

For example, in the control unit 99A, based on the acquired image data, the number of driving each of the piezoelectric elements 60 _{1 to} 60 _n in order to form an image to be recorded is set in advance by the image forming process (the process of step 104 above). ) Count before. Then, based on the count result, the image forming process is started for the piezoelectric element 60 whose count number is equal to or lower than a temperature as a threshold value that causes an increase in ink viscosity that causes deterioration in image quality. After the process of step 104), the heat generation process of step 114 may be executed every predetermined time.
In this case, a predetermined drive condition signal may be used as the drive condition signal.

  In the processing routine shown in FIG. 18, the control unit 99A measures the temperature of the ink around each piezoelectric element 60 every predetermined time after starting ink ejection (image formation) based on the acquired image data. Although the case where the heating resistor 37 is driven based on the measurement result has been described, the processing from step 110 to step 114 may be executed immediately before the drive signal is output to each piezoelectric element 60. In addition, before starting the image forming process in step 104, all the heating resistors 37 are output before the image forming process by outputting a predetermined drive condition signal to all the heating resistor control circuits 50B at once. You may make it drive.

(Second Embodiment)
Next, a second embodiment of the inkjet recording head 32 will be described. In the following description, the same components, members, and the like as those of the ink jet recording head 32 of the first embodiment are denoted by the same reference numerals, and detailed description thereof (including operation) is omitted.

As shown in FIG. 19, in the ink jet recording head 32 of the second embodiment, the side on which the nozzles 36 are formed is the lower side. In the ink jet recording head 32 of the second embodiment, the piezoelectric element 60 is formed on the opposite side of the pressure chamber 82 with the diaphragm 70 interposed therebetween, and does not face the pressure chamber 82.
For this reason, the heating resistor 37 is provided at a position where it does not directly contact the ink in the inkjet recording head 32.

  That is, the top plate 41 made of a silicon substrate or a glass substrate is laminated on the upper surface of the flow path substrate 76, and the ink pool chamber 80 is formed on the upper surface of the top plate 41. The top plate 41, the flow path substrate 76, the vibration plate 70, and the ink supply path 90 (ink supply through-hole 92) formed in the silicon substrate 40 are formed below the LOCOS film 44 constituting the vibration plate 70. The pressure chamber 82 and the ink pool chamber 80 are connected to each other. That is, the LOCOS film 44 as the second layer is configured to face the pressure chamber 82, and the reliability of the discharge performance can be improved.

  Further, in the ink jet recording head 32 of the second embodiment, a hollow air chamber 98 is formed between the top plate 41 and the piezoelectric element 60 (TEOS film 66). The air chamber 98 prevents the drive of the piezoelectric element 60 and the vibration of the vibration plate 70 from being affected (the drive of the piezoelectric element 60 and the vibration of the vibration plate 70 are allowed). For this reason, the reliability of discharge performance can be improved.

  Further, in the ink jet recording head 32 of the second embodiment, the heating resistor 37 is provided at a position not in direct contact with the ink in the ink jet recording head 32, so the heating efficiency of the ink in the ink jet recording head 32 is as follows. Although inferior to the ink jet recording head 32 of the first embodiment, by efficiently heating the piezoelectric element substrate 71 itself, it is possible to suppress a decrease in ejection properties and variations in the ink jet recording head 32.

(Third embodiment)
Next, a third embodiment of the inkjet recording head 32 will be described. In the following description, the same components, members, and the like as those of the ink jet recording head 32 of the first embodiment are denoted by the same reference numerals, and detailed description thereof (including operation) is omitted.

  As shown in FIG. 20, the ink jet recording head 32 according to the third embodiment is similar to the ink jet recording head 32 according to the second embodiment. The plate 41 is not laminated, and the heating resistor 37 can be directly contacted with the ink in the ink pool chamber 80.

  As described above, in the ink jet recording head 32 of the third embodiment, the heating resistor 37 is provided in a region continuous with the ink pool chamber 80 and can directly heat the ink stored in the ink pool chamber 80. Therefore, the reliability of the ejection performance can be improved, and the ink in each inkjet recording head 32 can be efficiently heated for each region continuous with each piezoelectric element 60.

(Fourth embodiment)
Next, a fourth embodiment of the inkjet recording head 32 will be described. In the squid, the same components, members and the like as those of the ink jet recording head 32 of the first embodiment are denoted by the same reference numerals, and detailed description thereof (including operation) is omitted.

As shown in FIG. 21, in the ink jet recording head 32 of the fourth embodiment, the heating resistor 37 is laminated between the diaphragm 70 and the lower electrode 58 in the ink jet recording head 32 of the second embodiment. ing.
As described above, the heating resistor 37 only needs to be integrally formed on the piezoelectric element substrate 71, and may be laminated on the piezoelectric element 60 as shown in the first to third embodiments. However, other than on the piezoelectric element 60, for example, it may be provided between the diaphragm 70 and the lower electrode 58 as shown in FIG.

  As shown in the first to third embodiments, when the heating resistor 37 is laminated on the piezoelectric element 60, the ink N in the pressure chamber 82 can be effectively heated. As shown in the fourth embodiment, when the heating resistor 37 is provided between the vibration plate 70 and the lower electrode 58, the piezoelectric element substrate 71 itself can be effectively heated. Even when the ink jet recording head 32 itself is placed in a low temperature environment of a predetermined temperature or lower, it is possible to suppress image quality deterioration due to fluctuations in the ejection amount of ink droplets ejected from the nozzles 36 due to environmental temperature fluctuations. It becomes possible.

It is a schematic front view which shows an inkjet recording device. It is explanatory drawing which shows the arrangement | sequence of an inkjet recording head. It is explanatory drawing which shows the relationship between the width | variety of a recording medium, and the width | variety of a printing area. FIG. 2 is a schematic plan view schematically showing the configuration of the first embodiment of the ink jet recording head. It is a schematic sectional drawing which shows the structure of 1st Embodiment of an inkjet recording head. It is a schematic sectional drawing which shows the structure of a heating resistor. It is explanatory drawing which shows the process (A)-(C) which manufactures an inkjet recording head. It is explanatory drawing which shows process (D)-(E) which manufactures an inkjet recording head. It is explanatory drawing which shows the process (F) which manufactures an inkjet recording head. It is explanatory drawing which shows the process (G) which manufactures an inkjet recording head. It is explanatory drawing which shows the process (O) which manufactures an inkjet recording head. Explanatory drawing which shows process (H)-(I) which manufactures an inkjet recording head Explanatory drawing which shows the process (J)-(K) which manufactures an inkjet recording head Explanatory drawing which shows the process (L) which manufactures an inkjet recording head. Explanatory drawing which shows the process (M) which manufactures an inkjet recording head. FIG. 2 is a schematic diagram showing an electrical configuration of an ink jet recording head. 2 is a schematic plan view schematically showing the configuration of an ink jet recording head. FIG. It is a flowchart which shows the process performed by a control part. It is a schematic sectional drawing which shows the structure of 2nd Embodiment of an inkjet recording head. It is a schematic sectional drawing which shows the structure of 3rd Embodiment of an inkjet recording head. It is a schematic sectional drawing which shows the structure of 4th Embodiment of an inkjet recording head. It is a schematic plan view which shows typically the case where a heating resistor is provided in a meandering shape.

Explanation of symbols

10 inkjet recording apparatus 30 jet recording unit 32 inkjet recording head 33 connecting electrode 36 nozzles 37, 37 ₁ to 37 _n heating resistor 37A heating resistor layer 37B autoxidation film 39 heating resistor drive electrodes 43 heating resistor drive lines 50 driven Elements 50A, 50A _{1 to} 50A _n Each piezoelectric element control circuit 50B, 50B _{1 to} 50B _n Heating resistor control circuit 52 Electrical wiring 56 Electrical wiring 58 Lower electrode 60 Piezoelectric element 64 Upper electrode 68 Electrical wiring 69 Electrical wiring 70 Diaphragm 71 Piezoelectric element substrate 72 Metal wiring 80 Ink pool chamber 82 Pressure chamber 99B Memory 99A Control unit 106 Temperature detection circuit

Claims (14)

A piezoelectric element having a piezoelectric body, a first electrode provided on one side of the piezoelectric body, and a second electrode provided on the other side of the piezoelectric body;
A first layer provided with the second electrode of the piezoelectric element on one side;
A second layer provided on the other side of the first layer;
A first electrical wiring formed between the first layer and the second layer;
A second electrical wiring connecting the first electrical wiring and the second electrode;
Comprising a piezoelectric element substrate having
The droplet discharge head, wherein the piezoelectric element substrate has a heating resistor for generating heat.   The heating resistor is laminated on the piezoelectric body through at least one of the first layer, the second layer, and the first wiring. 2. A droplet discharge head according to 1.   The droplet discharge head according to claim 1, wherein the heating resistor is laminated on the piezoelectric body.   The droplet discharge head according to claim 1, wherein the heating resistor is provided in a meandering manner along the surface of the piezoelectric element.   The droplet discharge head according to claim 1, wherein the heating resistor is configured by laminating a self-oxide film on the heating resistor layer.   6. The liquid droplet ejection head according to claim 5, wherein the self-oxidized film is formed by self-oxidizing a surface of the heating resistor layer.   The droplet discharge head according to claim 1, wherein the heating resistor includes a silicon silicide of Ta.   The droplet discharge head according to claim 1, wherein the heating resistor includes TaSiO. A pressure chamber that communicates with a nozzle that ejects droplets and is filled with liquid;
A flow path for supplying a liquid to the pressure chamber,
The droplet discharge head according to claim 1, wherein the heating resistor is provided in contact with the pressure chamber.   2. The droplet discharge head according to claim 1, wherein the piezoelectric element substrate includes a plurality of the piezoelectric elements, and a plurality of the heating resistors are provided corresponding to each of the piezoelectric elements. A plurality of heating resistor driving means for driving each of the plurality of heating resistors;
Temperature measuring means for measuring the environmental temperature of each of the plurality of piezoelectric elements;
A storage unit in which a relationship between a driving condition for obtaining the same droplet discharge condition as a predetermined temperature condition and an environmental temperature is stored;
Corresponding to each of the plurality of piezoelectric elements so that each of the plurality of heating resistors is driven under a driving condition corresponding to the environmental temperature measured by the temperature measuring unit based on the relationship between the driving condition and the environmental temperature. Control means for controlling each of the heating resistor driving means;
The droplet discharge head according to claim 10, further comprising: The piezoelectric element substrate is
A heating resistor driving means disposed between the piezoelectric bodies and driving the heating resistor;
A heating resistor driving electrode connected to the heating resistor and the heating resistor driving means;
A connection electrode connecting the heating resistor and the first electrode;
Piezoelectric element driving means for connecting the first electrical wiring and disposed between the piezoelectric bodies and driving the piezoelectric element;
A third electrical wiring connecting the piezoelectric element driving means and the first electrode;
The droplet discharge head according to claim 1, further comprising:   The droplet discharge head according to claim 1, wherein the first electric wiring is formed in a region where the piezoelectric body is formed in a plan view.   A liquid droplet ejection apparatus comprising the liquid droplet ejection head according to claim 1.