JP2013059934A - Liquid ejection head, and liquid ejection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection head having high ejection efficiency which increases displacement of a vibrating plate with a simple structure without increasing the cost.SOLUTION: The liquid ejection head includes: a liquid chamber having a nozzle for ejecting liquid; and a piezoelectric element in which a piezoelectric layer and an electrode are laminated on the opposite side of the nozzle of the liquid chamber. Voltage is applied to the piezoelectric element to deform the piezoelectric layer, and generation of pressure in the liquid chamber causes the liquid to be ejected from the nozzle. An electric field is applied in a direction substantially perpendicular to a polarization direction of the piezoelectric layer and in the substantially same direction as the polarization direction of the piezoelectric layer to deform the piezoelectric layer, and then the liquid is ejected from the nozzle. As a result, the displacement of the piezoelectric layer is increased to improve the ejection efficiency of the liquid ejection head.

Description

  The present invention relates to a liquid discharge head that discharges liquid such as ink, and a liquid discharge apparatus including the liquid discharge head.

  Inkjet printers as liquid ejection devices equipped with inkjet heads (liquid ejection heads) have recently achieved high image quality, low price, and speed compatibility (from high-speed printers by increasing or decreasing the number of nozzles that eject ink, but at lower speeds and lower prices). It has been popularized and has been widely used, and further improvements in image quality, cost reduction, and downsizing are required.

  As a method for manufacturing such an ink jet head, a MEMS (Micro Electro Mechanical Systems) technique, which is a fine processing technique using a semiconductor process, is adopted.

  By using the MEMS technology, components such as a liquid chamber, a diaphragm, a piezoelectric element, and an electrode necessary for an ink jet head can be formed on a silicon substrate in a minute region by a processing method such as etching or sputtering. Further, by miniaturizing these components and devising the arrangement of the components, the inkjet head can be made smaller and built.

  Here, when the degree of integration of each component increases due to the downsizing of the ink jet head, the area of the diaphragm that changes the pressure of the liquid chamber also decreases, and the displacement amount of the diaphragm decreases, so the discharge efficiency decreases. Occur.

  For this reason, for example, in Patent Document 1, a piezoelectric diaphragm that deforms by applying a potential difference in a direction orthogonal to the polarization direction is disposed opposite to each other, and a concave groove is formed in a portion of the diaphragm where the electric field strength is low. A technique for ensuring the amount of displacement of the diaphragm by forming it is disclosed.

  Further, for example, in Patent Document 2, an electric field perpendicular to the polarization direction is generated in a laminated piezoelectric body and deformed in a shear mode, and at the same time, an electric field parallel to the polarization direction of the outer piezoelectric ceramic layer is generated to generate an outer piezoelectric. An ink jet head has been proposed in which the deformation amount of the entire piezoelectric body is increased by deforming the layer in the expansion / contraction mode.

  Further, for example, in Patent Document 3, an annular upper electrode is formed in the piezoelectric layer, and a central electrode that is not in contact with the upper electrode is formed in the upper electrode, and a voltage is applied between the upper electrode and the lower electrode when voltage is applied to the upper electrode. In addition to the displacement caused by the above, a liquid ejection head is disclosed in which a displacement in the vertical direction is generated between the upper electrode and the center electrode, thereby increasing the deflection displacement amount of the diaphragm.

  However, in Patent Document 1, the deformation mode generated in the piezoelectric body is single, and a sufficient amount of displacement may not be obtained. In addition, in the inkjet head according to Patent Document 2, since a plurality of piezoelectric bodies having different deformation modes are stacked, it is expensive to manufacture, and it may be difficult to balance the appropriate thickness and Young's modulus of each piezoelectric body. is there. Furthermore, in Patent Document 3, it may be difficult to generate an electric field that sufficiently draws out the vertical displacement between the upper electrode and the center electrode. Further, there are problems such as an increase in cost and connection reliability for connecting the upper electrode to the lower electrode through the piezoelectric layer.

  Accordingly, an object of the present invention is to provide a liquid discharge head having a high discharge efficiency and a liquid discharge apparatus including the liquid discharge head without increasing the cost by increasing the displacement amount of the diaphragm with a simple structure. .

  In view of the above problems, the present invention has a liquid chamber provided with a nozzle for discharging a liquid, and a piezoelectric element in which a piezoelectric layer and an electrode are laminated on the opposite side of the liquid chamber from the nozzle, A liquid discharge head that discharges the liquid from the nozzle by applying a voltage to the piezoelectric element to deform the piezoelectric layer and generating pressure in the liquid chamber, and is substantially orthogonal to the polarization direction of the piezoelectric layer An electric field is applied in a direction substantially the same as the direction of polarization of the piezoelectric layer and the piezoelectric layer is deformed to discharge the liquid from the nozzle.

  According to the embodiments of the present invention, it is sufficient to form different modes of deformation in the same piezoelectric layer by deforming the piezoelectric layer by applying an electric field in a direction substantially orthogonal to the polarization direction of the piezoelectric layer and in substantially the same direction. A displacement amount can be secured.

  Therefore, the drive voltage can be reduced, and functional improvements such as downsizing of the IC, reduction of the wiring capacity and heat generation around the piezoelectric element can be expected, and the displacement of the piezoelectric layer can be increased, thereby making the diaphragm Controllability can be improved, and it can contribute to the improvement of particle formation characteristics such as droplet size reduction and multilevel.

  The liquid discharge head according to the embodiment of the present invention realizes low cost, high stability, and high reliability. According to the ink jet printer as the liquid discharge apparatus having such a liquid discharge head, It becomes possible to output a high quality image at low cost. Further, it can be mounted as a liquid discharge head on a liquid discharge apparatus such as a three-dimensional modeling apparatus or an infusion pump such as blood transfusion or infusion.

1 is an exploded perspective view of a liquid ejection head according to a first embodiment. The principal part enlarged view of the cross section of the width direction of the liquid discharge head which concerns on 1st Embodiment. II sectional view of the liquid ejection head shown in FIG. The figure which shows the structure by which the diaphragm is formed only in the part which covers a 3rd electrode in the liquid discharge head which concerns on 1st Embodiment. The principal part enlarged view of the cross section of the width direction of the liquid discharge head which concerns on 2nd Embodiment. The principal part enlarged view of the cross section of the width direction of the liquid discharge head which concerns on 3rd Embodiment. Schematic plan view and cross-sectional schematic diagram showing the configuration of the liquid ejection head according to the fourth embodiment The principal part enlarged view of the cross section of the width direction of the liquid discharge head which concerns on 5th Embodiment The principal part enlarged view and plane schematic of the cross section of the width direction of the liquid discharge head which concern on 6th Embodiment The principal part enlarged view and plane schematic of the cross section of the width direction of the liquid discharge head which concern on 6th Embodiment Schematic plan view and cross-sectional schematic diagram of a liquid ejection head according to a sixth embodiment 1 is a diagram illustrating a configuration example of an ink jet recording apparatus equipped with a liquid discharge head according to an embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.

[First Embodiment]
A schematic configuration of the liquid discharge head according to the first embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is an exploded perspective view of the liquid discharge head according to the first embodiment, and FIG. 2 is an enlarged view of a main part of a cross section in the width direction of the liquid discharge head according to the first embodiment. Here, in the drawing, the X direction indicates the width direction of the liquid ejection head, the Y direction indicates the longitudinal direction, and the Z direction indicates the height direction.

  In the liquid discharge head according to the first embodiment, a diaphragm 13 is formed on one surface of the liquid chamber substrate 2, and a nozzle on which the plurality of nozzles are arranged on the opposite side of the liquid chamber substrate 2 from the diaphragm 13. Bonded to the substrate 4. As shown in FIG. 1, the driving IC 21, the subframe 12, the SUS plates 341, 342, 343, the damper film 35, the reinforcing plate 36, and the top plate 38 are laminated on the liquid chamber substrate 2 on which the diaphragm 13 is formed. As a result, a liquid discharge head is formed.

  The diaphragm 13 generally has a laminated structure, and is composed of SiO2, SiN, PS, or the like. Also, Zr or other materials such as ceramics may be used.

  As shown in FIG. 2, the liquid chamber 1 is formed on the liquid chamber substrate 2 by etching, and is formed by etching stop with the vibration plate 13.

  A piezoelectric layer 7 is formed on the side of the diaphragm 13 opposite to the liquid chamber 1. The piezoelectric layer 7 may be formed by a method such as sputtering, SolGel, or ion plating, and may be formed by firing a green sheet.

  FIG. 3 is a cross-sectional view taken along the line II of the liquid discharge head shown in FIG.

  As shown in FIG. 3, the electrode for driving the piezoelectric layer 7 is a first electrode having a lower electrode 5 and an upper electrode 6 formed by sandwiching the piezoelectric layer 7 at a position corresponding to the periphery of the liquid chamber 1. 9, corresponding to the liquid chamber 1 of the piezoelectric layer 7 and the second electrode 10 formed on the opposite side of the liquid chamber 1 at a position corresponding to the liquid chamber 1 of the piezoelectric layer 7 and having a polarity different from that of the first electrode 9. The first electrode 10 and the third electrode 11 having the same polarity are formed on the liquid chamber 1 side.

  The portion of the third electrode 11 excluding the electrode outlet for power feeding is formed to be larger than the projection surface of the second electrode 10 on the liquid chamber 1 side of the piezoelectric layer 7. This is because if the third electrode 11 is formed smaller than the second electrode 10, the electric field formed between the first electrode 9 and the second electrode 10 becomes weak. A diaphragm 13 is provided so as to cover at least the third electrode 11. Each of the electrodes 9, 10, 11 is made of, for example, Ti, TiO 2, Pt, SrRuO 3, etc., and is appropriately selected from these materials and formed as an electrode.

  The liquid ejection head according to the present embodiment applies a voltage to a piezoelectric element composed of the piezoelectric layer 7 and the first electrode 9, the second electrode 10, and the third electrode 11 to deform the piezoelectric layer 7, The liquid is discharged from the nozzle 3 by generating a pressure on the nozzle 1.

  When the piezoelectric layer 7 is processed in the polarization direction 8 shown in FIG. 3 depending on the manufacturing method, the first electrode 9 and the second electrode 10 are grounded as a common electrode, and the third electrode 11 is individually set. Let it be an electrode. Further, when the polarization direction of the piezoelectric layer 7 is opposite to the example shown in FIG. 3 (downward in the figure), the first electrode 9 and the second electrode 10 are used as individual electrodes, and the third electrode 11 is used as a ground. .

  The piezoelectric layer 7 is deformed in the d31 mode when an electric field in substantially the same direction with respect to the polarization direction 8 is applied, and in the d15 mode when an electric field in a direction substantially orthogonal to the polarization direction 8 is applied.

  By switching the individual electrodes in such a configuration, a d15 mode deformation is obtained between the first electrode 9 and the third electrode 11, and a d31 mode deformation is obtained between the second electrode 10 and the third electrode 11. be able to. By forming the third electrode 11 larger than the second electrode 10, the electric field of the d15 mode deformable portion can be kept strong.

  The nozzle plate 4 in which the nozzle 3 is opened, for example, is formed on a SUS plate having a thickness of 50 μm by a press method, and is bonded to the surface of the liquid chamber substrate 2 opposite to the vibration plate 13.

  As shown in FIG. 2, the liquid chamber 1 is arranged in a two-row staggered pattern on the liquid chamber substrate 2 at a position facing the drive IC 21. Liquid (ink in the case of an inkjet head) is supplied to the liquid chamber 1 from the common liquid chamber 30 through the supply groove 31, the supply port 32, and the fluid resistance portion 33.

  A subframe 12 provided with a space 40 surrounding the deformed portion of the piezoelectric layer 7 is bonded to the opposite side of the piezoelectric layer 7 from the liquid chamber 1. The subframe 12 is formed of, for example, a silicon substrate or a glass substrate. In addition, an opening 39 is formed in the subframe 12 between the spaces 40, and the driving IC 21 is electrically connected to each electrode. A liquid supply groove 31 is formed on the opposite side of the opening 39 of the space 40 and communicates with a supply port 32 provided in the liquid chamber substrate 2.

  A plurality of SUS plates 341, 342, 343 in which holes constituting the common liquid chamber 30 are formed are stacked and joined to the upper portion of the subframe 12. A damper film 35 is joined to the upper part of the common liquid chamber 30, and a reinforcing plate 36 in which a space 37 having a hole in part is formed is joined. A top plate 38 is joined to the upper portion of the reinforcing plate 36, and a supply hole 42 is formed as shown in FIG.

  When a voltage is applied to each electrode 9, 10, 11 by a signal from the drive IC 21, an electric field is formed between the first electrode 9 and the second electrode 10 in a direction substantially orthogonal to the polarization direction 8. The piezoelectric layer 7 is deformed in d15 mode.

  In addition, an electric field in a direction substantially the same as the polarization direction 8 is formed between the second electrode 10 and the third electrode 11, and d31 mode deformation occurs in the piezoelectric layer 7.

  The diaphragm 13 is displaced from the base of the beam by the deformation of the d15 mode, and a large amount of displacement can be obtained by a synergistic effect that generates a unimorph displacement of the d31 mode at the center. Further, the first electrode 9 may be configured by only the lower electrode 5 without the upper electrode 6.

  FIG. 4 shows a configuration in which the diaphragm 13 is formed only in a portion covering the third electrode in the liquid ejection head according to the first embodiment.

  The diaphragm 13 is unnecessary for the deformation of the piezoelectric layer 7 in the d15 mode, and the diaphragm 13 for unimorph displacement is necessary for the deformation of the d31 mode. Therefore, it is possible to obtain a larger amount of displacement by forming the diaphragm 13 only in the portion covering the third electrode and not forming the diaphragm 13 in the deformed portion of the d15 mode. However, when the liquid is conductive, an insulating protective film 14 is required as shown in FIG.

  According to the liquid discharge head according to the first embodiment, the deformation efficiency can be improved by causing the piezoelectric layer 7 to deform in the d15 mode and the d31 mode. Therefore, the drive voltage can be lowered, and effects such as cost reduction and power consumption reduction can be obtained. Further, by reducing the drive voltage, it is possible to obtain significant functional improvements such as downsizing the drive IC 21 and lowering the wiring capacity and heat generation around the piezoelectric layer 7. Further, by increasing the displacement amount of the piezoelectric layer 7, the controllability of the diaphragm 13 is improved, and the particle formation characteristics such as droplet size reduction and multi-value conversion are improved.

[Second Embodiment]
Next, a liquid ejection head according to the second embodiment will be described. The overall configuration of the liquid ejection head is the same as that of the first embodiment shown in FIGS. 1 and 2.

  FIG. 5 is an enlarged view of a main part of a cross section in the width direction of the liquid discharge head according to the second embodiment.

  As shown in FIG. 5A, in the liquid ejection head according to the second embodiment, the diaphragm 13 in the deformation region of the d15 mode between the lower electrode 5 and the third electrode 11 of the first electrode 9 A thin portion 17 is formed. Thereby, the restraining force of the piezoelectric layer 7 by the diaphragm 13 can be reduced, and the displacement amount of the piezoelectric layer 7 in the d15 mode can be increased.

  Further, as shown in FIG. 5 (b), the vibration plate 13 in the deformation region of the d15 mode between the lower electrode 5 and the third electrode 11 of the first electrode 9 is provided with a notch 18, thereby vibrating. The restraining force of the piezoelectric layer 7 by the plate 13 can be further reduced. By forming the notch 18, the amount of displacement of the piezoelectric layer 7 in the d15 mode can be further increased.

  The thin portion 17 or the notch portion 18 formed on the diaphragm 13 has an effect of increasing the displacement amount of the d15 mode, and can increase the displacement amount of the entire piezoelectric layer 7.

  In this case, the piezoelectric layer 7 needs to have a certain thickness to ensure strength, and preferably has a thickness of 1 μm or more. In addition, the piezoelectric layer 7 may be provided with a protective film on the side in contact with the liquid and the opposite side as needed.

[Third Embodiment]
FIG. 6 is an enlarged view of a main part of a cross section in the width direction of the liquid discharge head according to the third embodiment. The overall configuration of the liquid ejection head according to the third embodiment is the same as the configuration of the first embodiment shown in FIGS. 1 and 2.

  As shown in FIG. 6A, in the liquid ejection head according to the third embodiment, a fourth electrode having the same polarity as the third electrode 11 is disposed between the upper electrode 6 and the second electrode 10 of the first electrode 9. An electrode 19 is provided. With this configuration, the piezoelectric layer 7 is deformed in the d15 mode between the first electrode 9 and the third electrode 11 and similarly in the d15 mode between the first electrode 9 and the fourth electrode 19. Can be made. Therefore, the electric field strength in the d15 mode can be increased, and a further effect of improving the displacement amount of the piezoelectric layer 7 can be obtained.

  FIG. 6B shows a configuration in which a notch 18 is formed in the diaphragm 13 between the lower electrode 5 and the third electrode 11 of the first electrode 9 in the liquid ejection head according to the third embodiment. Show.

  By providing the notch 18, the restraining force of the piezoelectric layer 7 by the diaphragm 13 can be reduced, and the amount of displacement of the piezoelectric layer 7 in the d15 mode can be further increased. Further, by forming the thin portion 17 between the first electrode 9 and the fourth electrode 19 of the diaphragm 13 in the same manner as in FIG. Can be obtained.

[Fourth Embodiment]
FIG. 7 is a diagram illustrating a configuration of a liquid ejection apparatus according to the fourth embodiment. 7A is a schematic plan view of a liquid ejection apparatus according to the fourth embodiment, FIG. 7B is a schematic cross-sectional view taken along the line II-II of FIG. 7A, and FIG. 3) is a schematic cross-sectional view along III-III.

  As shown in FIG. 7B, an insulating layer 20 is formed on the opposite side of the piezoelectric layer 7 of the second electrode 10, and contacts the insulating layer 20 inside the deformed portion of the piezoelectric layer 7. A hole 22 is provided. A lead electrode 23 is led out from the second electrode 10 through the contact hole 22, and a stud bump for flip-chip bonding between the aluminum pad 25 provided in the drive IC 21 and the gold plating 26 provided thereon. By providing 24 on the lead electrode 23, the drive IC 21 and the second electrode 10 are electrically joined.

  In order to reduce the influence from the adjacent piezoelectric layer 7 in the conventional piezoelectric layer 7 driven only by the deformation of the d31 mode, a notch is formed between the adjacent piezoelectric layers 7 to each liquid chamber 1. It was formed by patterning. When the degree of integration is about 50 dpi or less, there is little influence from the adjacent piezoelectric layer 7, so this is not a big problem, but when the degree of integration is 150 dpi or more, the end width cannot be taken sufficiently and the mutual restraint is not achieved. In some cases, the amount of displacement of the piezoelectric layer 7 is reduced due to the influence of force.

  In order to pattern the piezoelectric layer 7 for each liquid chamber 1, it is necessary to form the piezoelectric layer 7 by removing unnecessary portions by etching processing such as sputtering. Sputter etching of the piezoelectric layer 7 takes time for processing and the processing apparatus is expensive, so an increase in cost is inevitable, and problems due to etching residues and the like are also a major issue.

  However, in the liquid ejection head according to the present embodiment, since the piezoelectric layer 7 can be sufficiently deformed by causing the piezoelectric layer 7 to be deformed by the d15 mode and the d31 mode, the piezoelectric layer 7 is attached to each liquid chamber 1. It is not necessary to pattern and form.

  In particular, the influence of the restraining force of the piezoelectric layer 7 from the diaphragm 13 is small, and by providing a notch in the deformed portion of the piezoelectric layer 7 of the diaphragm 13 in the d15 mode, the influence of the restraining force can be almost eliminated. it can. Therefore, the piezoelectric layer 7 can be formed as a uniform layer formed on the entire liquid discharge head without being patterned for each liquid chamber 1.

  Therefore, it is not necessary to pattern the piezoelectric element that becomes the actuator of the liquid discharge head, and the cost of equipment and process can be greatly reduced.

[Fifth Embodiment]
FIG. 8 is an enlarged view of a main part of a cross section in the width direction of the liquid discharge head according to the fifth embodiment. Except for the configuration shown in the figure, the configuration is the same as the configuration of the liquid ejection head according to the first embodiment shown in FIGS. 1 and 2.

  FIG. 8A is a diagram illustrating a configuration in which a notch portion 27 is provided between the deformed portion in the d15 mode and the deformed portion in the d31 mode of the piezoelectric layer 7.

  The third electrode 11 is also provided with third electrodes 111 and 112 on the first electrode 9 side of the notch 27 so that the piezoelectric layer 7 can be deformed and driven in the d15 mode. The second electrode 10 may be approximately the same size as the third electrode 11. Since the space called the notch 27 is formed in the piezoelectric layer 7, a strong electric field is not formed between the third electrodes 111 and 112 and the second electrode 10, and the second electrodes 111 and 112 and the first electrode are not formed. A strong electric field is formed between

  Further, since the influence of the restraining force is reduced by thinning the portion where the notch 27 is formed instead of the notch, the amount of displacement of the piezoelectric layer 7 can be increased.

  FIG. 8B shows a fourth electrode 19 having the same polarity as the third electrode 11 facing the third electrodes 111 and 112 in order to strengthen the electric field between the first electrode 9 and the third electrodes 111 and 112. Is provided.

  With such a configuration, the fourth electrode 19 forms an electric field with the first electrode 9, and the displacement amount of the piezoelectric layer 7 due to the d15 mode can be increased.

  FIG. 8C shows a view in which a thin portion 17 is formed at the end of the liquid chamber 1 of the diaphragm 13.

  When the thin portion 17 is formed so as to overlap the notch portion 27, the displacement amount of the piezoelectric layer 7 can be further increased. In this case, since the force to return to the original after the piezoelectric layer 7 is displaced becomes small, it is necessary to appropriately design the dimension of the thin portion 17 so that the displacement amount and the force to return to the original are optimized.

  FIG. 8D shows an example in which a notch 18 is provided at the end of the liquid chamber 1 of the diaphragm 13.

  By providing the notch 18 between the deformed portion of the piezoelectric layer 7 in the d15 mode and the deformed portion in the d31 mode, the influence of the mutual deformed mode can be reduced and the amount of displacement of each can be maximized. . Further, by providing the fourth electrode 19, a larger displacement amount of the piezoelectric layer 7 can be obtained.

  In this manner, by forming the cutout portion 27 or the thin layer portion in the piezoelectric layer 7, the displacement amount of the piezoelectric layer 7 can be increased. Further, the displacement amount can be further increased by forming the fourth electrode 19 or forming the thin portion 17 or the notch portion 18 in the diaphragm 13.

[Sixth Embodiment]
FIG. 9 is an enlarged view of a main part and a schematic plan view of a cross section in the width direction of a liquid ejection head according to a sixth embodiment. The configuration not shown is the same as the configuration of the liquid ejection head according to the first embodiment shown in FIGS. 1 and 2.

  In the liquid discharge head according to the sixth embodiment, as shown in FIG. 9B, the cross section parallel to the piezoelectric layer 7 of the liquid chamber 1 is formed in an oval shape. The electrode 10 and the third electrode 11 are formed in an oval shape similar to the cross-sectional shape of the liquid chamber 1, and the liquid chamber 1 and the electrodes 9, 10, 11 are stacked concentrically.

  By configuring the deformed portion of the piezoelectric layer 7 in a circular shape, an oval shape, or a part of a rectangular shape in combination, the diaphragm 13 can be efficiently deformed.

  Further, as shown in FIG. 10, by providing a notch 27 between the deformed portion of the piezoelectric layer 7 due to the d15 mode and the deformed portion due to the d31 mode, a larger displacement amount of the piezoelectric layer 7 can be obtained. it can.

  FIG. 11 shows an example in which the liquid chamber 1 and the electrodes 9, 10, 11 and the like shown in FIGS. 9 and 10 are arranged on a four-row staggered pattern. A liquid ejection head of 1200 dpi can be realized by making 300 dpi per row with such a configuration.

  The liquid flow path including the liquid chamber 1 includes, for example, SUS plates 341, 342, 343, and 344 having a thickness of 50 μm, openings of the liquid chamber 1, openings of the fluid resistance portion 33 and the communication pipe 42, and the common liquid chamber 30. And an opening portion of the communication pipe 42, and can be configured by aligning and laminating each.

  In this way, a plurality of thin plates having openings are laminated and joined to form the communication pipe 42, the common liquid chamber 30, and the like, so that the manufacturing cost per nozzle can be reduced, and stability and reliability are improved. An excellent liquid discharge head can be realized.

  In the electrode substrate 41, an electrode pad is formed by gold plating or the like on the extraction electrode 29 from the extraction wiring portion 28 of the second electrode 10 shown in FIGS. 10 and 11, and the second electrode 10 and the electrode substrate 41 are formed by flip chip bonding. It is electrically joined to the drive IC mounted on the board.

  By passing the extraction wiring portion 28 between the liquid chambers 1 and consolidating the extraction electrodes 29 on the right side of FIG. 11, the area of the electrode substrate 41 can be reduced, and the cost can be reduced.

  With the arrangement as shown in FIG. 11, the liquid discharge head can be highly integrated, and when used in an inkjet recording apparatus or the like, a liquid discharge head capable of high definition and high image quality can be realized.

[Seventh Embodiment]
FIG. 12 shows a configuration example of an ink jet recording apparatus equipped with a liquid discharge head according to an embodiment of the present invention.

  The ink jet recording apparatus includes line heads 51, 52, 53, and 54, which are liquid discharge heads that discharge four colors of ink of black (Bk), cyan (C), magenta (M), and yellow (Y). Is done.

  The line heads 51, 52, 53, 54 are driven by the driving IC 21 based on image data input from a host computer (not shown), and form a color image by discharging ink onto the printing surface of the recording paper 61.

  The recording paper 61 is separated from the paper feed cassette 47 by the paper feed roller 60 and conveyed one by one. The recording paper 61 is guided to the paper pressing roller 49 while the leading end is guided by the guide plate 48.

  The conveyance belt 45 is wound around the belt driving roller 44 and the belt driven roller 43 with an appropriate tension. For example, the conveyance belt 45 is an apparatus that conveys the recording paper 61 fixed to the conveyance belt 45 by an electrostatic adsorption device, an air suction device, or the like. It has.

  The belt driven roller 43 is provided with a paper pressing roller 49 with the conveyance belt 45 interposed therebetween, so that the recording paper 61 can be brought into close contact with the conveyance belt 45.

  A platen 46 for keeping the distance between the recording paper 61 and each of the line heads 51, 52, 53, 54 is disposed inside the conveyor belt 45.

  A pre-processing unit 50 is provided in a previous stage in which an image is formed on the recording paper 61 by the line heads 51, 52, 53, and 54. For example, the pretreatment unit 50 attaches a pretreatment agent such as an ink fixing agent, a coagulant, or a swelling agent to the recording paper 61. Specifically, a liquid discharge head that discharges the pretreatment agent or an application roller that can apply the pretreatment agent can be used.

  The recording paper 61 is conveyed in close contact with the conveying belt 45, and, for example, an ink coagulant or the like is applied onto the recording paper 61 in advance by the preprocessing unit 50. Thereafter, ink of each color is ejected from the line heads 51, 52, 53, and 54 onto the recording paper 61 to form an image.

  The recording paper 61 on which the image is formed by the line heads 51, 52, 53, 54 is post-processed by the post-processing unit 55 in the subsequent stage. The post-processing unit 55 is, for example, a heat roller for drying ink on the recording paper 61, a dryer, a decurling unit for correcting curling of the recording paper 61, or the like.

  The post-processed recording paper 61 is separated from the transport belt 45 by a separation claw 56 and discharged to a paper discharge cassette 59 by a pair of paper discharge rollers 57 and 58.

  As the line heads 51, 52, 53, 54, the liquid discharge head according to any one of the first to sixth embodiments described above is used, thereby reducing the power consumption and improving the droplet controllability. An ink jet recording apparatus that can provide a high-quality image with excellent tonality at low cost can be realized.

  In addition, although the ink jet recording apparatus as the liquid ejecting apparatus has been described, the liquid ejecting heads shown in the first to sixth embodiments can also be used for the infusion pump used for intravenous drip injection or the like. With such a configuration, it is possible to provide an infusion pump as a liquid ejection device that is small in size and has a wide range of infusion volume. Furthermore, it is also possible to use the liquid ejection head according to the embodiment of the present invention in a three-dimensional modeling apparatus that uses inkjet technology.

  As described above, according to the embodiment of the present invention, the amount of displacement of the piezoelectric layer 7 can be increased by causing the piezoelectric layer 7 of the liquid ejection head to be deformed by the d15 mode and the d31 mode. In this manner, the displacement amount can be increased with a simple configuration to improve the discharge efficiency, so that the cost and power consumption can be reduced.

  In addition, it is possible to easily control the liquid droplets to be discharged by increasing the amount of displacement. Therefore, an inkjet recording apparatus using the liquid discharge head can output a high-quality image with excellent gradation characteristics at low cost.

  It should be noted that the present invention is not limited to the configuration shown here, such as a combination with other elements in the configuration described in the above embodiment. These points can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form.

1 Liquid chamber 3 Nozzle 5 Lower electrode (first electrode)
6 Upper electrode (first electrode)
7 Piezoelectric layer 8 Polarization direction 9 1st electrode 10 2nd electrode 11 3rd electrode 13 Diaphragm 17 Thin part 18, 27 Notch 19 4th electrode 30 Common liquid chamber 42 Communication pipes 341, 342, 343, 344 Thin plate

JP-A-7-214773 Japanese Patent Laid-Open No. 10-058674 JP 2010-208300 A

Claims (12)

A liquid chamber provided with a nozzle for discharging liquid;
A piezoelectric element in which a piezoelectric layer and an electrode are laminated on the opposite side of the liquid chamber from the nozzle,
A liquid discharge head that discharges the liquid from the nozzle by applying a voltage to the piezoelectric element to deform the piezoelectric layer and generating pressure in the liquid chamber;
An electric field is applied in a direction substantially perpendicular to a polarization direction of the piezoelectric layer and in a direction substantially the same as the polarization direction of the piezoelectric layer, and the piezoelectric layer is deformed to discharge the liquid from the nozzle. Liquid discharge head. The piezoelectric layer is deformed in a d15 mode when an electric field in a direction substantially orthogonal to the polarization direction is applied, and is deformed in a d31 mode by applying an electric field in a direction substantially the same as the polarization direction. The liquid discharge head according to claim 1. The electrode of the piezoelectric element is
A first electrode formed by sandwiching the piezoelectric layer at a position corresponding to a peripheral portion of the liquid chamber of the piezoelectric layer;
A second electrode formed on the opposite side of the liquid chamber at a position corresponding to the liquid chamber of the piezoelectric layer and having a polarity different from that of the first electrode;
A third electrode having the same polarity as the first electrode, formed on the liquid chamber side at a position corresponding to the liquid chamber of the piezoelectric layer;
With
A diaphragm covering at least the third electrode is provided;
3. The liquid ejection head according to claim 1, wherein a voltage is applied between each of the first electrode, the second electrode, and the third electrode. The third electrode is formed such that a portion excluding an electrode outlet for power feeding is formed larger than a projection surface of the piezoelectric layer on the liquid chamber side of the second electrode. 4. A liquid discharge head according to 3. 5. The liquid ejection head according to claim 3, wherein the vibration plate is formed such that a portion corresponding to the deformed portion in the d15 mode of the piezoelectric layer is thinner than other portions. The notch part is formed in the said diaphragm between the deformation | transformation part in the said d15 mode of the said piezoelectric layer, and the deformation part in the said d31 mode, The Claim 3 or 4 characterized by the above-mentioned. Liquid discharge head. 6. The liquid ejection head according to claim 3, further comprising a fourth electrode having the same polarity as the third electrode between the first electrode and the second electrode. 7. The liquid ejection head according to claim 1, wherein the piezoelectric layer is a uniform layer formed over the entire head. The said piezoelectric layer has a thin layer part or a notch between the displacement part in the said d15 mode, and the displacement part in the said d31 mode, It is any one of Claim 1 to 7 characterized by the above-mentioned. Liquid discharge head. The cross section of the liquid chamber parallel to the piezoelectric layer is circular or oval,
10. The electrode according to claim 1, wherein the electrode is formed in a shape similar to a cross-sectional shape of the liquid chamber, and the liquid chamber and the electrode are stacked concentrically. Liquid discharge head. By laminating and joining a plurality of thin plates having openings,
The liquid according to any one of claims 1 to 10, wherein a communication pipe connected from the liquid chamber to the nozzle and a common liquid chamber for supplying the liquid to the liquid chamber are formed. Discharge head. A liquid discharge apparatus comprising the liquid discharge head according to claim 1.

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