JP2017210000A - Inkjet head and inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet head and an inkjet recording apparatus according to an embodiment, capable of shortening the maximum length between a common-electrode connection terminal and each drive element, and improving reliability by stably driving each drive element.SOLUTION: An inkjet head comprises a nozzle plate; a common electrode; and an individual electrode. The nozzle plate has a plurality of nozzles formed thereon. The common electrode is connected to a plurality of actuators and applies a voltage to the actuators. The individual electrode applies a voltage to the individual actuators. The actuators are divided into a plurality of groups, and the individual electrode and the common electrode are provided for every group. A parallel section on which a plurality of individual-electrode connection terminals to be connected to the individual electrode are provided in parallel, is provided in an end portion of the nozzle plate. Common-electrode connection terminals are disposed in an outside portion of the parallel section having the individual-electrode connection terminals and between the individual-electrode connection terminals, respectively.SELECTED DRAWING: Figure 2

Description

  Embodiments described herein relate generally to an inkjet head and an inkjet recording apparatus.

  The on-demand type ink jet recording method is a method in which ink droplets are ejected from nozzles in accordance with image signals to form an image with ink droplets on recording paper. The on-demand ink jet recording system includes a heating element type and a piezoelectric element type.

  In the heating element type, a heating element in the ink flow path generates bubbles in the ink. Ink droplets pushed by the bubbles are ejected from the nozzles. On the other hand, in the piezoelectric element type, a piezoelectric element (piezo element) that is an actuator is deformed to cause a pressure change in the ink stored in the ink chamber. Thereby, the pressurized ink droplet is ejected from the nozzle.

An ink jet head as an example of a piezoelectric element type includes a plurality of nozzles and a plurality of actuators corresponding to the individual nozzles. The actuator includes a piezoelectric element, and a common electrode and an individual electrode that apply a voltage to the piezoelectric element. The common electrode and the individual electrode are electrically connected to the drive circuit via conductor patterns, respectively. When a driving voltage is applied from the driving circuit to the piezoelectric element via the common electrode and the individual electrode, the piezoelectric element is deformed.
As a result, the ink supplied to the ink pressure chamber is pressurized. Part of the pressurized ink is ejected from the nozzle as ink droplets.

JP 2014-14967 A JP 2013-215930 A JP 2005-39986 A

  In an inkjet head having a large number of drive elements, in the case of a structure having a common electrode, connection terminals between the common electrode and an external element for applying a voltage are arranged only at the end of the head body. In such a configuration, the maximum distance between the connection terminal of the common electrode and the drive element becomes longer as the size of the head body increases. For this reason, voltage fluctuation due to wiring resistance occurs, which may affect the driving of each driving element.

  In addition, since the difference between the longest distance and the shortest distance between the connection terminal of the common electrode and the drive element is large, the voltage fluctuation difference between the drive elements becomes large, and the drive stability of each drive element is low. There is a possibility. Further, when the connection terminal of the common electrode is arranged only at the end of the head main body, current concentration occurs, and there is a concern about problems such as short circuit and wiring breakage.

  In the present embodiment, the longest distance between the connection terminal of the common electrode and the drive element can be shortened, and the stability can be improved by driving each drive element stably. It is to provide a recording apparatus.

  An inkjet head according to one embodiment includes a nozzle plate, a common electrode, and individual electrodes. The nozzle plate is formed with a plurality of nozzles. The common electrode is connected to a plurality of actuators and applies a voltage to the actuators. Individual electrodes apply voltages to individual actuators. A plurality of actuators are divided into a plurality of groups, and an individual electrode and a common electrode are provided for each group. A juxtaposed portion in which connection terminals of a plurality of individual electrodes connected to the individual electrodes are juxtaposed is provided at the end of the nozzle plate. The connection terminal of the common electrode was disposed between the outer portion of the juxtaposed portion of the connection terminal of the individual electrode and between the connection terminals of the individual electrode.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing a schematic configuration of an entire inkjet printer according to a first embodiment. FIG. 2 is a plan view showing the main configuration of the ink jet head according to the first embodiment. The longitudinal cross-sectional view of the principal part which shows the connection state of the individual electrode of the inkjet head of 1st Embodiment, and the connection terminal of an individual electrode. The longitudinal cross-sectional view of the principal part which shows the connection state of the common electrode of the inkjet head of 1st Embodiment, and the connection terminal of a common electrode.

(Constitution)
The first embodiment will be described below with reference to FIGS. 1 to 4. Note that one or more examples of other expressions may be attached to each element capable of a plurality of expressions. However, this does not deny that a different expression is given for an element to which no other expression is attached, and does not restrict other expressions not illustrated. Each drawing schematically shows an embodiment, and the size of each element shown in the drawing may differ from the explanation of the embodiment.

  FIG. 1 is a longitudinal sectional view showing a schematic configuration of the entire inkjet printer 1 according to the first embodiment. The ink jet printer 1 is an example of an ink jet recording apparatus. The ink jet recording apparatus is not limited to this, and may be another apparatus such as a copying machine.

  As shown in FIG. 1, the inkjet printer 1 performs various processes such as image formation while conveying a recording paper P that is a recording medium, for example. The ink jet printer 1 includes a housing 10, a paper feed cassette 11, a paper discharge tray 12, a holding roller (drum) 13, a conveying device 14, a holding device 15, an image forming device 16, and a static elimination device 17. And a reversing device 18 and a cleaning device 19.

  The paper feed cassette 11 accommodates a plurality of recording papers P and is disposed in the housing 10. The paper discharge tray 12 is at the top of the housing 10. The recording paper P on which an image is formed by the ink jet printer 1 is discharged to the paper discharge tray 12.

  The transport device 14 has a plurality of guides and a plurality of transport rollers arranged along a path along which the recording paper P is transported. The transport roller is driven by a motor and rotates to transport the recording paper P from the paper feed cassette 11 to the paper discharge tray 12.

  The holding roller 13 has a cylindrical frame formed of a conductor and a thin insulating layer formed on the surface of the frame. The frame is grounded (ground connection). The holding roller 13 conveys the recording paper P by rotating while holding the recording paper P on the surface thereof.

  The holding device 15 holds the recording paper P carried out of the paper feed cassette 11 by the transport device 14 by adsorbing it on the surface (outer peripheral surface) of the holding roller 13. The holding device 15 presses the recording paper P against the holding roller 13 and then attracts the recording paper P to the holding roller 13 by electrostatic force due to charging.

  The image forming apparatus 16 forms an image on the recording paper P held on the outer surface of the holding roller 13 by the holding device 15. The image forming apparatus 16 includes a plurality of inkjet heads 21 that face the surface of the holding roller 13. The plurality of inkjet heads 21 form images by ejecting, for example, four colors of ink of cyan, magenta, yellow, and black onto the recording paper P, respectively.

  The neutralization peeling device 17 peels the recording paper P on which the image is formed from the holding roller 13 by neutralizing the recording paper P. The neutralization peeling device 17 supplies electric charges to neutralize the recording paper P, and inserts a claw between the recording paper P and the holding roller 13. As a result, the recording paper P is peeled off from the holding roller 13. The recording paper P peeled off from the holding roller 13 is transported by the transport device 14 to the paper discharge tray 12 or the reversing device 18.

  The cleaning device 19 cleans the holding roller 13. The cleaning device 19 is downstream of the static elimination device 17 in the rotation direction of the holding roller 13. The cleaning device 19 brings the cleaning member 19 a into contact with the surface of the rotating holding roller 13 and cleans the surface of the rotating holding roller 13.

  The reversing device 18 reverses the front and back surfaces of the recording paper P peeled from the holding roller 13 and supplies the recording paper P onto the front surface of the holding roller 13 again. The reversing device 18 reverses the recording paper P by, for example, conveying the recording paper P along a predetermined reversing path for switching back the recording paper P in the front-rear direction.

  FIG. 2 is a plan view showing the main configuration of the inkjet head 21. FIG. 3 is a longitudinal sectional view of a main part showing a connection state between the individual electrode (lower electrode portion 106c) of the inkjet head 21 and the connection terminal of the individual electrode. FIG. 4 is a longitudinal sectional view of a main part showing a connection state between the common electrode (upper electrode portion 107 c) of the inkjet head 21 and the connection terminal of the common electrode. 2, 3, and 4 show various elements that are originally hidden for the sake of explanation by solid lines.

  The ink jet printer 1 includes a plurality of ink tanks (not shown) connected to a plurality of ink jet heads 21 and a plurality of control units. The inkjet head 21 is connected to an ink tank that stores ink of a corresponding color.

  The inkjet head 21 forms characters and images by ejecting ink droplets onto the recording paper P held by the holding roller 13. As shown in FIGS. 3 and 4, the inkjet head 21 includes a nozzle plate 100, a pressure chamber structure 200, and an ink flow path structure 400. The pressure chamber structure 200 is an example of a base material.

  The nozzle plate 100 is formed in a rectangular plate shape. The nozzle plate 100 is formed as an integral structure on the pressure chamber structure 200. The nozzle plate 100 includes a plurality of nozzles (orifices and ink ejection holes) 101 and a plurality of driving elements (piezoelectric elements and actuators) 102.

  The plurality of nozzles 101 are circular holes. The diameter of the nozzle 101 is 20 μm, for example. As shown in FIG. 2, the plurality of nozzles 101 are arranged in a plurality of rows along the longitudinal direction (vertical direction in FIG. 2) and the short direction (horizontal direction in FIG. 2) of the nozzle plate 100. The nozzles 101 in one row and the nozzles 101 in the other row are arranged with a certain interval in the longitudinal direction of the nozzle plate 100. Thereby, the plurality of drive elements 102 are arranged with higher density.

  In the longitudinal direction of the nozzle plate 100, the distance between the centers of adjacent nozzles 101 is, for example, 340 μm. In the short direction of the nozzle plate 100 (left-right direction in FIG. 2), the distance between the two rows of the nozzles 101 is, for example, 240 μm.

  The plurality of drive elements 102 are arranged corresponding to the plurality of nozzles 101. In other words, the drive element 102 is located on the same axis as the corresponding nozzle 101. The drive element 102 is formed in an annular shape and surrounds the corresponding nozzle 101. The drive element 102 is not limited to this, and may be, for example, an annular shape (C-shape) with a part opened.

  The pressure chamber structure 200 is formed in a rectangular plate shape using a silicon wafer. The pressure chamber structure 200 is not limited to this, and may be another semiconductor such as silicon carbide (SiC) or a germanium substrate. The substrate is not limited to this, and may be formed of other materials such as ceramics, glass, quartz, resin, or metal. The ceramics used are, for example, alumina ceramics, zirconia, silicon carbide, silicon nitride or nitrides, carbides or oxides such as barium titanate. The resin used is, for example, a plastic material such as ABS (acrylonitrile butadiene styrene), polyacetal, polyamide, polycarbonate, or polyethersulfone. The metal used is, for example, aluminum or titanium. The thickness of the pressure chamber structure 200 is, for example, 725 μm. The thickness of the pressure chamber structure 200 is, for example, in the range of 100 to 775 μm.

  As shown in FIGS. 3 and 4, the pressure chamber structure 200 includes a first surface 200 a, a second surface 200 b, and a plurality of pressure chambers (ink chambers) 201. The first and second surfaces 200a and 200b are flattened. The second surface 200b is located on the opposite side of the first surface 200a. The nozzle plate 100 is fixed to the first surface 200a.

  The plurality of pressure chambers 201 are circular holes. The diameter of the pressure chamber 201 is, for example, 190 μm. The shape of the pressure chamber 201 is not limited to this. The pressure chamber 201 penetrates the pressure chamber structure 200 in the thickness direction and opens in the first and second surfaces 200a and 200b, respectively. The plurality of pressure chambers 201 that open to the first surface 200 a are closed by the nozzle plate 100.

  The plurality of pressure chambers 201 are arranged corresponding to the plurality of nozzles 101. In other words, the pressure chamber 201 is located on the same axis as the corresponding nozzle 101. For this reason, the corresponding nozzle 101 communicates with the pressure chamber 201. The pressure chamber 201 is connected to the outside of the inkjet head 21 via the nozzle 101.

  The ink flow path structure 400 is formed in a rectangular plate shape using, for example, stainless steel. The thickness of the ink flow path structure 400 is, for example, 4 mm. The material of the ink flow path structure 400 is not limited to stainless steel. For example, you may form with other materials like ceramics or resin. The ceramics used are, for example, alumina ceramics, zirconia, silicon carbide, nitrides such as silicon nitride, carbides or oxides. The resin used is, for example, a plastic material such as ABS, polyacetal, polyamide, polycarbonate, or polyethersulfone. The material of the ink flow path structure 400 is selected in consideration of the difference in expansion coefficient with the nozzle plate 100 so as not to affect the generation of pressure for ejecting ink.

  The ink flow path structure 400 is bonded to the pressure chamber structure 200 by, for example, an epoxy adhesive. The ink flow path structure 400 includes an ink flow path 401, an ink supply port (not shown), and an ink discharge port.

  The ink flow path 401 is a groove formed on the surface of the ink flow path structure 400. The depth of the ink flow path 401 is 2 mm, for example. The ink supply port opens at one end of the ink flow path. The ink supply port is connected to the ink tank via a tube, for example. The ink tank is connected to the plurality of pressure chambers 201 via the ink flow path 401.

  The ink in the ink tank flows into the ink flow path 401 through the ink supply port. The ink supplied to the ink flow path 401 is supplied to the plurality of pressure chambers 201. The ink filled in the pressure chamber 201 also flows into the nozzle 101 that opens in the pressure chamber 201. The ink jet printer 1 keeps the ink in the nozzle 101 by keeping the ink pressure at an appropriate negative pressure. The ink causes a meniscus in the nozzle 101 and is maintained so as not to leak from the nozzle 101.

  The ink discharge port opens at the other end of the ink flow path 401. The ink discharge port is connected to the ink tank via a tube, for example. The ink in the ink flow path 401 that has not flowed into the pressure chamber 201 is discharged to the ink tank through the ink discharge port. In this way, ink circulates between the ink tank and the ink flow path 401. As the ink circulates, the temperature of the inkjet head 21 and the ink is kept constant, and, for example, the quality of the ink due to heat is suppressed.

  Next, the nozzle plate 100 will be described in detail. As shown in FIGS. 3 and 4, the nozzle plate 100 includes the nozzle 101 and the driving element 102, the diaphragm 104, the insulating film 105, the lower electrode 106, the upper electrode 107, the protective film 108, and the repellent film. And an ink film 109. The insulating film 105 and the protective film 108 are an example of an insulating part.

The diaphragm 104 is formed in a rectangular plate shape by, for example, SiO ₂ (silicon dioxide) formed on the first surface 200a of the pressure chamber structure 200. In other words, the diaphragm 104 is an oxide film of the pressure chamber structure 200 that is a silicon wafer. The diaphragm 104 is formed of other materials such as single crystal Si (silicon), Al ₂ O ₃ (aluminum oxide), HfO ₂ (hafnium oxide), ZrO ₂ (zirconium oxide), or DLC (Diamond Like Carbon). May be. The thickness of the diaphragm 104 is, for example, 4 μm. The thickness of the diaphragm 104 is generally in the range of 1 to 50 μm.

  The diaphragm 104 has a first surface 104a and a second surface 104b. The first surface 104 a is fixed to the pressure chamber structure 200 and closes the plurality of pressure chambers 201. The second surface 104b is located on the opposite side of the first surface 104a.

  The lower electrode 106 is formed on the second surface 104 b of the diaphragm 104. As shown in FIGS. 2 and 3, the lower electrode 106 includes a wiring portion 106 a, an individual connection terminal portion 106 b, and a lower electrode portion (individual electrode) 106 c in contact with the piezoelectric film 111. The terminal portion 106 b of the lower electrode 106 has a juxtaposed portion 106 f that is located at one end portion in the short direction of the diaphragm 104 and is arranged along the longitudinal direction of the diaphragm 104.

  As shown in FIGS. 2 and 4, the upper electrode 107 includes a wiring portion 107 a, a common connection terminal portion 107 b, and an upper electrode portion (common electrode) 107 c in contact with the piezoelectric film 111. The terminal portion 107b is located at one end of the diaphragm 104 in the short side direction, and is located between and at both ends with the juxtaposed portion 106f of the terminal portion 106b disposed along the longitudinal direction of the diaphragm 104. .

The lower electrode 106 is, for example, a thin film of Pt (platinum) and Al (aluminum).
The wiring portion 107a and the terminal portion 107b of the upper electrode 107 are, for example, thin films of Ti (titanium) and Al. The lower electrode 106 and the upper electrode 107 are Ni (nickel), Cu (copper), Al (aluminum), Ag (silver), Ti (titanium), W (tungsten), Mo (molybdenum), Au (gold). It may be formed of other materials such as

  The thickness of the lower electrode 106 and the upper electrode 107 is, for example, 0.5 μm. The film thicknesses of the lower electrode 106 and the upper electrode 107 are generally in the range of 0.01 to 1 μm. The width of the wiring portion 106a of the lower electrode 106 and the wiring portion 107a of the upper electrode 107 is, for example, 10 μm.

  As shown in FIGS. 3 and 4, the driving element 102 includes a lower electrode portion 106 c in contact with the piezoelectric film 111, a piezoelectric film 111, and an upper electrode portion 107 c in contact with the piezoelectric film 111. On the surface 104b. The drive element 102 generates a pressure for ejecting ink droplets from the corresponding nozzle 101 in the ink in the corresponding pressure chamber 201.

  An electrode portion 106 c in contact with the piezoelectric film 111 of the lower electrode 106 is on the second surface 104 b of the diaphragm 104. The electrode part 106 c is formed in an annular shape surrounding the nozzle 101. The electrode part 106 c is located on the same axis as the nozzle 101. The outer diameter of the electrode portion 106c is, for example, 133 μm. The inner diameter of the electrode part 106c is, for example, 30 μm. For this reason, the electrode portion 106c has a portion 106d that does not contact the piezoelectric film 111 in the electrode portion 106c that is separated from the nozzle 101, and ensures electrical continuity by being in contact with the wiring portion 106a.

  The wiring part 106a of the lower electrode 106 connects the electrode part 106c and the terminal part 106b of the corresponding driving element 102. The wiring portion 106 a extends in the short direction of the nozzle plate 100 and between the drive elements 102 adjacent to each other in the longitudinal direction of the nozzle plate 100.

  As shown in FIGS. 3 and 4, the piezoelectric film 111 surrounds the nozzle 101 and is formed in an annular shape having substantially the same size as the electrode portion 106 c of the lower electrode 106. The piezoelectric film 111 is formed slightly smaller than the electrode portion 106c of the lower electrode 106, but may be larger than the electrode portion 106c. The piezoelectric film 111 is located on the same axis as the nozzle 101. The piezoelectric film 111 covers the electrode part 106 c of the lower electrode 106.

The piezoelectric film 111 is a film of lead zirconate titanate (PZT) which is a piezoelectric material. The piezoelectric film 111 is not limited to this, for example, PTO (PbTiO _3: lead _{titanate), PMNT (Pb (Mg 1/3} Nb 2/3) O 3 -PbTiO 3), PZNT (Pb (Zn 1 / ₃ Nb _2/3 ) O ₃ —PbTiO ₃ ), ZnO, and AlN may be used to form the piezoelectric material.

  The thickness of the piezoelectric film 111 is 2 μm, for example. The thickness of the piezoelectric film is determined by, for example, the piezoelectric characteristics and the breakdown voltage. The thickness of the piezoelectric film is generally in the range of 0.1 μm to 5 μm.

  The piezoelectric film 111 generates polarization in the thickness direction. When an electric field in the same direction as the direction of polarization is applied to the piezoelectric film 111, the piezoelectric film 111 expands and contracts in a direction orthogonal to the direction of the electric field. In other words, the piezoelectric film 111 contracts or expands in a direction (in-plane direction) orthogonal to the film thickness.

  When a ferroelectric such as PZT is used as the piezoelectric film 111, polarization inversion occurs by applying an electric field opposite to the polarization direction. Therefore, it is possible to apply an electric field substantially only in the same direction as the polarization direction, and by applying the electric field, the piezoelectric film 111 extends in the film thickness direction and is perpendicular to the film thickness (in-plane direction). ).

  The electrode portion 107 c of the upper electrode 107 surrounds the nozzle 101 and is formed in an annular shape having substantially the same size as the electrode portion 106 c of the lower electrode 106 and the piezoelectric film 111. The electrode portion 107 c of the upper electrode 107 is formed slightly smaller than the piezoelectric film 111, but may be larger than the piezoelectric film 111. The electrode part 107 c is located on the same axis as the nozzle 101. The electrode part 107 c covers the piezoelectric film 111. In other words, the electrode portion 107 c is provided on the ejection side (side facing the ink jet head 21) of the piezoelectric film 111.

  The piezoelectric film 111 is interposed between the electrode portion 106 c of the lower electrode 106 and the electrode portion 107 c of the upper electrode 107. In other words, the electrode portion 106 c of the lower electrode 106 and the electrode portion 107 c of the upper electrode 107 overlap the piezoelectric film 111. The piezoelectric film 111 insulates between the two electrode portions 106c and 107c. The electrode portion 107 c of the upper electrode 107 faces the electrode portion 106 c of the lower electrode 106 with the piezoelectric film 111 interposed therebetween.

  The electrode portion 107 c of the upper electrode 107 forms the outer surface 102 a of the drive element 102. The outer surface 102 a is one surface of the driving element 102 facing the opposite side of the diaphragm 104. In other words, the outer surface 102 a faces the ejection side of the drive element 102. The outer surface 102 a is a surface that is substantially parallel to the second surface 104 b of the diaphragm 104.

  The insulating film 105 covers the second surface 104 b of the vibration plate 104, the surface of the driving element 102, and the wiring portion 106 a of the lower electrode 106. The insulating film 105 has a plurality of holes 105 b that expose the terminal portions 106 b of the lower electrode 106.

Insulating film 105 is formed by, for example, SiO _2. The insulating film 105 may be formed of other materials such as SiN (silicon nitride), for example. The insulating film 105 has a substantially uniform thickness on the second surface 104 b of the vibration plate 104, the surface of the driving element 102, and the lower electrode portion 106 c of the lower electrode 106. The thickness of the insulating film 105 is 1 μm. The thickness of the insulating film 105 is preferably in the range of about 0.1 μm to 5 μm.
Note that the thickness of the insulating film 105 may be partially different.

  The insulating film 105 has a plurality of contact portions 113. The contact portion 113 is a hole 105 c provided in a part of the insulating film 105 on the outer surface 102 a of the corresponding driving element 102. The contact portion 113 is formed in a circular shape with a diameter of 20 μm, for example. The hole 105 b of the contact portion 113 exposes a part of the portion 107 d that does not contact the piezoelectric film 111. Further, the hole 105 c of the contact portion 113 exposes a part of the electrode portion 107 c of the upper electrode 107. The hole 105c of the contact portion 113 is disposed closer to the outer periphery of the electrode portion 107c than the center between the inner periphery and the outer periphery of the annular electrode portion 107c.

  As shown in FIG. 4, the common connection terminal portion 107 b of the upper electrode 107 and the wiring portion 107 a are on the surface 105 a of the insulating film 105. In other words, the terminal portion 107 b and the wiring portion 107 a of the upper electrode 107 are on the insulating film 105. The surface 105 a of the insulating film 105 faces in the opposite direction of the diaphragm 104.

  As shown in FIGS. 3 and 4, the wiring portion 107a of the upper electrode 107 connects the corresponding electrode portion 107c of the driving element 102 and the common connection terminal portion 107b. The wiring portion 107 a extends in the short direction of the nozzle plate 100.

  As shown in FIG. 2, the wiring portion 107 a is united in the vicinity of the center of the nozzle plate 100 in the short direction, and forms a portion extending along the longitudinal direction of the nozzle plate 100. Therefore, the common connection terminal portion 107b and the eight electrode portions 107c are connected by the wiring portion 107a. On the other hand, the wiring portion 107a that is connected to the driving element 102 at the end portion in the short-side direction and is periodically drawn to the end portion side of the nozzle plate 100 is connected to the common connection terminal portion 107b, and is common to each driving element 102. It arrange | positions so that the distance with the connection terminal part 107b may become short.

  As shown in FIG. 4, the wiring portion 107 a of the upper electrode 107 passes through the surface 105 a of the insulating film 105 that covers the driving element 102. One end of the wiring portion 107 a is connected to the electrode portion 107 c of the upper electrode 107 through the contact portion 113. In other words, the contact portion 113 is a portion where the insulating film 105 is partially removed in order to connect the wiring portion 107a to the electrode portion 107c.

  The insulating film 105 separates the wiring portion 107 a of the upper electrode 107 and the electrode portion 106 c of the lower electrode 106. The insulating film 105 prevents the lower electrode 106 and the upper electrode 107 from being electrically connected.

  The protective film 108 is on the second surface 104 b of the diaphragm 104. The protective film 108 is formed of, for example, a photosensitive polyimide such as Photo Nice (registered trademark) manufactured by Toray Industries, Inc. That is, the protective film 108 is different from the insulating film 105 and is formed of an insulating material. The protective film 108 is not limited to this, and may be formed of other insulating materials such as resin or ceramics. Resins used are plastic materials such as other types of polyimide, ABS, polyacetal, polyamide, polycarbonate, and polyethersulfone. The ceramics used are, for example, nitrides such as zirconia, silicon carbide, silicon nitride, barium titanate, or oxides. In addition, the protective film 108 may be formed of a metal material as long as it has an insulating property with respect to the driving element 102 and the upper electrode 107. The metal material is, for example, aluminum, SUS, or titanium.

  The material of the protective film 108 is selected in consideration of heat resistance, insulation, thermal expansion coefficient, smoothness, and ink wettability. When the ink jet printer 1 uses ink having high conductivity, the insulating property of the material can affect the degree of ink deterioration when the drive element 102 is driven.

  The protective film 108 covers the second surface 104 b of the diaphragm 104, the surface 105 a of the insulating film 105, and the wiring portion 107 a of the upper electrode 107. In other words, the protective film 108 covers the driving element 102 and the wiring part 106 a of the lower electrode 106 from above the insulating film 105. The protective film 108 protects the driving element 102, the lower electrode 106, and the upper electrode 107 from, for example, ink or moisture in the air. The protective film 108 has a plurality of holes that expose the plurality of terminal portions 106b and 107b of the lower electrode 106 and the upper electrode 107, respectively.

The material of the protective film 108 differs from the material of the diaphragm 104 in Young's modulus. The Young's modulus of SiO ₂ forming the diaphragm 104 is 80.6 GPa. On the other hand, the Young's modulus of the polyimide forming the protective film 108 is 4 GPa. That is, the Young's modulus of the protective film 108 is smaller than the Young's modulus of the diaphragm 104.

  The surface 108a of the protective film 108 is formed to be roughly smooth, but has minute irregularities. For example, in the portion where the driving element 102 is provided, the surface 108a of the protective film 108 is raised as compared with other portions. The surface 108 a of the protective film 108 is located on the opposite side of the surface fixed to the diaphragm 104.

The thickness of the protective film 108 other than the portion where the driving element 102, the lower electrode 106, and the upper electrode 107 are present is about 4 μm. The thickness of the protective film 108 is approximately in the range of 1 to 50 μm.
The thickness of the protective film 108 is the distance from the second surface 104 b of the diaphragm 104 to the surface 108 a of the protective film 108. The thickness of the protective film 108 formed on the driving element 102 is about 2.5 μm. The thickness of the protective film 108 is a distance from the surface 105 a of the insulating film 105 on the driving element 102 to the surface 108 a of the protective film 108.

  The ink repellent film 109 covers the protective film 108 and a part of the insulating film 105. The ink repellent film 109 is formed of a silicone-based liquid repellent material or a fluorine-containing organic material having liquid repellency, such as Cytop (registered trademark) of Asahi Glass Co., Ltd. The ink repellent film 109 may be formed of other materials.

  The ink repellent film 109 is exposed without covering the protective film 108 around the terminal portion 106 b of the lower electrode 106 and the terminal portion 107 b of the upper electrode 107. The surface 109 a of the ink repellent film 109 forms the surface of the nozzle plate 100. The surface 109 a of the ink repellent film 109 is located on the opposite side of the surface fixed to the protective film 108.

  The thickness of the ink repellent film 109 other than the portion where the drive element 102, the upper electrode 107, and the lower electrode 106 are present is, for example, 1 μm. The thickness of the ink repellent film 109 is preferably in the range of 0.01 to 10 μm, for example. The thickness of the ink repellent film 109 in the portion where the driving element 102 is provided is thinner than the other portions. The thickness of the ink repellent film 109 may be constant.

  If the ink droplets ejected by the nozzle 101 adhere to the vicinity of the nozzle 101, there is a possibility that the stability of ink ejection is lowered. The ink repellent film 109 suppresses ink droplets from adhering to the surface of the nozzle plate 100.

The nozzle 101 passes through the vibration plate 104, the protective film 108, and the ink repellent film 109.
In other words, the nozzle 101 is formed on the vibration plate 104, the protective film 108, and the ink repellent film 109. Since the vibration plate 104 and the protective film 108 have ink affinity (liquid affinity), the meniscus of the ink stored in the pressure chamber 201 is kept in the nozzle 101. A part of the protective film 108 is interposed between the nozzle 101 and the inner peripheral surface of the driving element 102.

  A control unit (not shown) is connected to the terminal portion 106b of the lower electrode 106 through, for example, a flexible cable. The control unit is, for example, an IC that controls the inkjet head 21 or a microcomputer that controls the inkjet printer 1. On the other hand, the terminal portion 107b of the upper electrode 107 is connected to, for example, GND (ground ground = 0V).

  The control unit causes the lower electrode 106 to transmit a signal for driving the corresponding driving element 102. The lower electrode 106 is used as an individual electrode for operating the plurality of driving elements 102 independently.

  The inkjet head 21 performs printing (image formation) as follows, for example. A print instruction signal is input to the control unit by a user operation. The control unit applies signals to the plurality of drive elements 102 based on the print instruction. In other words, the control unit applies a driving voltage to the electrode part 106 c of the lower electrode 106.

  When a signal is applied to the electrode portion 106 c of the lower electrode 106, a potential difference is generated between the electrode portion 106 c of the lower electrode 106 and the electrode portion 107 c of the upper electrode 107. As a result, an electric field in the same direction as the polarization direction is applied to the piezoelectric film 111, and the drive element 102 expands and contracts in a direction orthogonal to the electric field direction.

  In such a nozzle plate 100, when the drive element 102 extends in a direction orthogonal to the electric field direction, the diaphragm 104 bends so as to reduce the volume of the pressure chamber 201. On the contrary, when the driving element 102 is contracted in a direction orthogonal to the electric field direction, the diaphragm 104 is curved so as to increase the volume of the pressure chamber 201. At this time, the insulating film 105 and the protective film 108 inhibit the bending.

  More specifically, as shown in FIGS. 3 and 4, the drive element 102 is sandwiched between the diaphragm 104, the insulating film 105, and the protective film 108. For this reason, when the driving element 102 extends in a direction orthogonal to the electric field direction, a force is applied to the diaphragm 104 to deform into a concave shape with respect to the pressure chamber 201 side. In other words, the diaphragm 104 tends to bend in a direction that increases the volume of the pressure chamber 201. On the other hand, the insulating film 105 and the protective film 108 are subjected to a force that deforms into a convex shape with respect to the pressure chamber 201 side. In other words, the insulating film 105 and the protective film 108 tend to bend in a direction that reduces the volume of the pressure chamber 201.

  On the other hand, when the driving element 102 is contracted in a direction orthogonal to the electric field direction, a force is applied to the diaphragm 104 so as to deform into a convex shape with respect to the pressure chamber 201 side. In other words, the diaphragm 104 tends to bend in a direction that reduces the volume of the pressure chamber 201. In addition, the insulating film 105 and the protective film 108 are subjected to a force that deforms into a concave shape with respect to the pressure chamber 201 side. In other words, the insulating film 105 and the protective film 108 tend to bend in a direction that increases the volume of the pressure chamber 201.

  As described above, the diaphragm 104, the insulating film 105, and the protective film 108 tend to bend in opposite directions. That is, the insulating portion formed by the insulating film 105 and the protective film 108 generates a force (film stress) that hinders the deformation of the diaphragm 104 by the driving element 102.

The amount of deformation of the member is affected by the Young's modulus and the thickness of the member. The polyimide forming the protective film 108 has a Young's modulus smaller than that of SiO ₂ forming the diaphragm 104. For this reason, the protective film 108 has a larger deformation amount for the same force than the diaphragm 104. Furthermore, the insulating film 105 is thinner than the diaphragm 104. For this reason, the amount of deformation of the insulating film 105 with respect to the same force is larger than that of the diaphragm 104.

  As described above, the drive element 102 operates in the bending mode (bending vibration). The drive element 102 changes the volume of the pressure chamber 201 by deforming the diaphragm 104 when a voltage is applied.

  First, the drive element 102 increases the volume of the pressure chamber 201 by deforming the diaphragm 104. As a result, a negative pressure is generated in the ink stored in the pressure chamber 201, and the ink flows from the ink flow path 401 into the pressure chamber 201.

  Next, the drive element 102 reduces the volume of the pressure chamber 201 by deforming the diaphragm 104. Thereby, the ink in the pressure chamber 201 is pressurized. The positive pressure applied to the ink does not escape to the ink flow path 401 and is confined in the pressure chamber 201. Thereby, the pressurized ink is ejected from the nozzle 101.

  The greater the difference in Young's modulus between the diaphragm 104 and the protective film 108, the lower the voltage at which ink can be ejected, and the ink jet head 21 can eject ink efficiently. Furthermore, the greater the difference in thickness between the insulating portion formed by the insulating film 105 and the protective film 108 and the diaphragm 104, the lower the voltage at which ink can be ejected, and the inkjet head 21 ejects ink efficiently. it can.

Next, an example of a method for manufacturing the inkjet head 21 will be described. First, an SiO ₂ film as the diaphragm 104 is formed over the entire first surface 200a of the pressure chamber structure 200 (silicon wafer) before the pressure chamber 201 is formed. The SiO ₂ film is formed by, for example, a thermal oxide film method. Note that the SiO ₂ film may be formed by other methods such as a CVD method.

  The silicon wafer forming the pressure chamber structure 200 is a single large disk. A plurality of pressure chamber structures 200 are later cut from the silicon wafer. However, the present invention is not limited to this, and one pressure chamber structure 200 may be formed from one rectangular silicon wafer.

  The silicon wafer is repeatedly heated and a thin film is formed in the manufacturing process of the inkjet head 21. For this reason, the silicon wafer has heat resistance, conforms to SEMI (Semiconductor Equipment and Materials International) standard, and is smoothed by mirror polishing.

  Next, a metal film for forming the lower electrode 106 is formed on the second surface 104 b of the vibration plate 104. First, a Ti film and a Pt film are sequentially formed by sputtering. The film thickness of Pt is, for example, 0.45 μm, and the film thickness of Ti is, for example, 0.05 μm. The metal film may be formed by other manufacturing methods such as vapor deposition and plating.

  Next, the piezoelectric film 111 is formed on the metal film that forms the lower electrode 106. The piezoelectric film 111 is formed by, for example, an RF magnetron sputtering method. At this time, the temperature of the silicon wafer is heated to 350 ° C., for example. After the film formation, the piezoelectric film 111 is heat treated at 650 ° C. for 3 hours in order to impart piezoelectricity to the piezoelectric film 111. Thereby, the piezoelectric film 111 obtains good crystallinity and good piezoelectric performance. The piezoelectric film 111 may be formed by other manufacturing methods such as a CVD (chemical vapor deposition method), a sol-gel method, an AD method (aerosol deposition method), and a hydrothermal synthesis method.

  Next, a Pt metal film for forming the electrode portion 107 c of the upper electrode 107 is formed on the piezoelectric film 111. The metal film is formed by, for example, a sputtering method. The metal film may be formed by other manufacturing methods such as vacuum deposition and plating.

  Next, the electrode part 107c of the upper electrode 107 and the piezoelectric film 111 are patterned by etching the metal film and the piezoelectric film 111. The patterning is performed by creating an etching mask on the metal film and removing the metal film and the piezoelectric film 111 other than the etching mask by etching. The metal film and the piezoelectric film 111 are patterned at a time. The metal film and the piezoelectric film 111 may be individually patterned. The etching mask is formed by application of a photosensitive resist, pre-baking, exposure using a mask on which a desired pattern is formed, development, and post-baking.

  Next, the lower electrode 106 is formed by patterning. For patterning, an etching mask is formed on the piezoelectric film 111 and the electrode portion 107c of the upper electrode 107 and the metal film (Pt / Ti) below the piezoelectric film 111, and the metal film other than the etching mask is etched. Do by removing. The etching mask is formed by application of a photosensitive resist, pre-baking, exposure using a mask on which a desired pattern is formed, development, and post-baking.

  The nozzle 101 is formed at the center between the electrode portions 106 c and 107 c of the lower electrode 106 and the upper electrode 107 and the piezoelectric film 111. For this reason, the part without the metal film and the piezoelectric film 111 which is concentric with the centers of the electrode portions 106c and 107c and the piezoelectric film 111 is formed. Thus, the drive element 102 is formed on the second surface 104b of the diaphragm 104. By the patterning, the diaphragm 104 is exposed except for the wiring portion 106a, the lower electrode portion 106c, and the driving element 102 of the lower electrode 106.

  Next, the insulating film 105 is formed on the second surface 104 b of the diaphragm 104 and the driving element 102. The insulating film 105 is formed by a CVD method that can realize good insulating properties at low temperature. The insulating film 105 is not limited to this, and may be formed by other methods such as sputtering or evaporation.

  The insulating film 105 is patterned after film formation. In order to form the nozzle 101, a portion without the insulating film 105 concentric with the center of the driving element 102 is formed. At the same time, the contact portion 113 is formed. The diameter of the portion without the insulating film 105 is, for example, 10 μm. The patterning is performed by removing the insulating film 105 other than the etching mask by etching. The etching mask is formed by application of a photosensitive resist, pre-baking, exposure using a mask on which a desired pattern is formed, development, fixing, and post-baking.

  Next, on the insulating film 105, a metal film for forming the wiring portion 106a and the terminal portion 106b of the lower electrode and the wiring portion 107a and the terminal portion 107b of the upper electrode 107 is formed. The metal film is, for example, a Ti (titanium) / Al (aluminum) thin film formed by a sputtering method. The film thickness of Ti is, for example, 0.1 μm, and the film thickness of Al is, for example, 0.4 μm. The metal film may be formed by other manufacturing methods such as vacuum deposition and plating. The metal film is connected to one of the electrode portion 106 c of the lower electrode 106 and the electrode portion 107 c of the upper electrode 107 through the contact portion 113.

  By patterning the metal film, the lower electrode wiring portion 106a and the terminal portion 106b, and the upper electrode 107 wiring portion 107a and the terminal portion 107b are formed. The patterning is performed by creating an etching mask on the metal film and removing the metal film other than the etching mask by etching. The etching mask is formed by application of a photosensitive resist, pre-baking, exposure using a mask on which a desired pattern is formed, development, and post-baking.

Next, the SiO ₂ film that forms the vibration plate 104 is patterned to form part of the nozzle 101. Patterning is made an etching mask on the SiO ₂ film performs SiO ₂ film other than the etching mask by removing by etching. The etching mask is formed by application of a photosensitive resist on the vibration plate 104, pre-baking, exposure using a mask on which a desired pattern is formed, development, and post-baking.

  Next, the protective film 108 is formed on the diaphragm 104, the insulating film 105, the wiring portion 106a and the terminal portion 106b of the lower electrode, and the wiring portion 107a and the terminal portion 107b of the upper electrode 107 by a spin coating method (spin coating). To do. That is, the protective film 108 that covers the insulating film 105 is formed. First, the second surface 104b of the diaphragm 104 and the insulating film 105 are covered with a solution containing a polyimide precursor. Next, the silicon wafer is rotated to smooth the solution surface. The protective film 108 is formed by performing thermal polymerization and solvent removal by baking.

  The method for forming the protective film 108 is not limited to spin coating. The protective film 108 may be formed by other methods such as CVD, vacuum deposition, or plating.

  By patterning the protective film 108, the nozzle 101 is formed, and the terminal portion 106b of the lower electrode 106 and the terminal portion 107b of the upper electrode 107 are exposed. The patterning is performed by a procedure corresponding to the material of the protective film 108.

  The case where the protective film 108 is formed of non-photosensitive polyimide such as Semico Fine (registered trademark) manufactured by Toray Industries, Inc. will be described. First, a solution containing a polyimide precursor is formed into a film by a spin coating method, subjected to thermal polymerization and solvent removal by baking, and then fired and molded. Thereafter, an etching mask is formed on the non-photosensitive polyimide film, and the polyimide film other than the etching mask is removed by etching to perform patterning. The etching mask is formed by application of a photosensitive resist on the non-photosensitive polyimide film, pre-baking, exposure using a mask on which a desired pattern is formed, development, and post-baking.

  The case where the protective film 108 is formed of, for example, photosensitive polyimide such as Photo Nice (registered trademark) manufactured by Toray Industries, Inc. will be described. First, the solution is deposited by spin coating and then pre-baked. Thereafter, patterning is performed through exposure using a mask and a development process. In the case of positive photosensitive polyimide, the mask has openings corresponding to the nozzle 101, the opening 115, the terminal portion 106b of the lower electrode 106, and the terminal portion 107b of the upper electrode 107 (light is transmitted). In the case of negative photosensitive polyimide, the mask shields light from portions corresponding to the nozzle 101, the opening 115, the terminal portion 106b of the lower electrode 106, and the terminal portion 107b of the upper electrode 107. Thereafter, post-baking is performed, and the protective film 108 is fired.

  Next, a cover tape is attached on the protective film 108. The cover tape is, for example, a back surface protective tape for chemical mechanical polishing (CMP) of a silicon wafer. The pressure chamber structure 200 to which the cover tape is attached is turned upside down to form a plurality of pressure chambers 201 in the pressure chamber structure 200. The pressure chamber 201 is formed by patterning.

  3 and 4 are cross-sectional views showing the ink jet head on which the insulating protective film of the first embodiment is formed. A vertical deep dry etching called Deep-RIE dedicated to a silicon substrate (for example, see International Publication No. 2003/030239) is performed to etch the pressure chamber structure 200 to form the pressure chamber 201. At this time, a resist mask having a desired pattern formed on the pressure chamber structure 200, which is a silicon wafer, is formed, whereby the pressure chamber 201 is formed in the desired pattern. The resist mask is formed by application of a photosensitive resist, pre-baking, exposure using a mask on which a desired pattern is formed, development, and post-baking.

The SF ₆ gas used for the etching does not exert an etching action on the SiO _{2 of the} diaphragm 104 and the polyimide of the protective film 108. Therefore, the progress of dry etching of the silicon wafer that forms the pressure chamber 201 stops at the vibration plate 104. In other words, the diaphragm 104 functions as a stop layer for the etching.

  Note that for the above-described etching, various methods such as a wet etching method using a chemical solution and a dry etching method using plasma may be used. Further, the etching method and etching conditions may be changed depending on the material.

  As described above, from the process of forming the drive element 102 and the nozzle 101 on the diaphragm 104 to the process of forming the pressure chamber 201 in the pressure chamber structure 200, the film formation technique, the photolithography etching technique, and the spin coating are performed. Done by law. For this reason, the nozzle 101, the drive element 102, and the pressure chamber 201 are precisely and easily formed on one silicon wafer.

  Next, the ink flow path structure 400 is bonded to the second surface 200 b of the pressure chamber structure 200. That is, the ink flow path structure 400 is bonded to the resist mask 210 with an epoxy adhesive.

  Next, a cover tape is attached to a part of the protective film 108 so as to cover the terminal portion 106 b of the lower electrode 106 and the terminal portion 107 b of the upper electrode 107. The cover tape is made of resin and can be easily detached from the protective film 108. The cover tape prevents dust and ink repellent film 109 from adhering to the terminal portion 106b of the lower electrode 106 and the terminal portion 107b of the upper electrode 107.

  Next, an ink repellent film 109 is formed on the protective film 108. The ink repellent film 109 is formed by spin coating a liquid ink repellent film material on the protective film 108. At this time, positive pressure air is injected from the ink supply port. Accordingly, positive pressure air is discharged from the nozzle 101 connected to the ink flow path 401. When a liquid ink repellent film material is applied in this state, the ink repellent film material is suppressed from adhering to the inner peripheral surface of the nozzle 101. After the ink repellent film 109 is formed, the cover tape is peeled off from the protective film 108.

Next, the silicon wafer is divided to form a plurality of inkjet heads 21.
The inkjet head 21 is mounted inside the inkjet printer 1. A control part is connected to the terminal part 106b of the lower electrode 106 through a flexible cable, for example.
Furthermore, the ink supply port and the ink discharge port of the ink flow path structure 400 are connected to the ink tank through, for example, a tube.

  As described above, in this embodiment, the nozzle plate 100 is formed on the pressure chamber structure 200. However, instead of creating the nozzle plate 100 on the pressure chamber structure 200, a part of the pressure chamber structure 200 may be used as the diaphragm 104. For example, the drive element 102 is formed on one surface of the pressure chamber structure 200, and a hole corresponding to the pressure chamber 201 is formed from the other surface side. The hole does not penetrate the pressure chamber structure 200. A thin layer remains on one surface side of the pressure chamber structure 200, and this portion operates as the diaphragm 104.

(Action / Effect)
Next, with reference to FIG. 2, the effect of 1st Embodiment of the said structure is demonstrated. According to the inkjet head 21 of the inkjet printer 1 of the first embodiment, the nozzle plate 100 in which a plurality of nozzles 101 are formed and the plurality of driving elements 102 corresponding to the individual nozzles 101 are provided. The nozzle plate 100 is connected to a plurality of driving elements 102, and an upper electrode portion 107c that is a common electrode that applies a voltage to the driving elements 102, and a lower electrode that is an individual electrode for applying a voltage to each driving element 102 Part 106c. Further, a juxtaposed portion 106f in which terminal portions 106b, which are connection terminals of a plurality of individual electrodes connected to the lower electrode portion 106c of the individual electrodes, are provided at the end of the nozzle plate 100.
Terminal portions 107b, which are connection terminals of the upper electrode portion 107c, which is a common electrode, are located between and at both ends with the juxtaposed portions 106f of the terminal portions 106b disposed along the longitudinal direction of the diaphragm 104. Accordingly, the connection terminal portion 107b of the upper electrode 107 can be pulled out to the end portion of the nozzle plate 100 with high frequency. Therefore, the upper electrode portion 107c and the connection terminal of each drive element 102 are compared with the case where the terminal portion 107b, which is a connection terminal between the upper electrode portion 107c and an external element for applying a voltage, is disposed only at the end of the head body. The distance to the portion 107b can be shortened. Therefore, the distance between each driving element 102 and the connection terminal portion 107b of the upper electrode portion 107c can be shortened, so that voltage fluctuation due to wiring resistance can be reduced. Furthermore, the difference between the longest distance and the shortest distance between the upper electrode portion 107c and the connection terminal portion 107b of each drive element 102 can be reduced. As a result, the voltage fluctuation difference between the drive elements 102 is reduced, and the drive stability can be maintained. In addition, current concentration can be avoided by providing the connection terminal portion 107b with a high frequency, and a decrease in yield due to occurrence of a short circuit or wiring breakage can be suppressed.

  In the present embodiment, the plurality of driving elements 102 are divided into a plurality of groups, and a lower electrode portion 106c that is an individual electrode and an upper electrode portion 107c that is a common electrode are provided for each group. . Here, as shown in FIG. 2, the eight drive elements 102 are made into one group, and the wiring portion 107 a of the upper electrode 107 is arranged between substantially the center positions of the respective drive elements 102. The wiring part 106a of the lower electrode 106 extends in a direction orthogonal to the arrangement direction of the wiring part 107a. Here, the wiring part 106 a of the lower electrode 106 is disposed on both sides of each lower electrode 106 with respect to the juxtaposed direction of the juxtaposed part 106 f of the terminal part 106 b of the lower electrode 106. Further, the wiring portion 106 a of the lower electrode 106 passes between the driving elements 102 in the other row adjacent in the longitudinal direction of the nozzle plate 100 and is drawn out to the terminal portion 106 b. Thereby, the drive elements 102 of each group can be regularly formed in the same shape, and the manufacture of the inkjet head 21 can be simplified.

  In the above embodiment, an example is shown in which eight drive elements 102 are grouped into one group, and the number of drive elements 102 included in all groups is the same. However, the drive elements 102 included in each group have the same number. The number is not necessarily the same, and the number of drive elements 102 included in each group may be changed. Also in this case, the difference between the longest distance and the shortest distance between the upper electrode portion 107c and the connection terminal portion 107b of each drive element 102 can be reduced. Therefore, by forming the connection terminal portion 107b of the upper electrode portion 107c frequently, the longest distance between the connection terminal portion 107b of the upper electrode portion 107c and the driving element 102 is shortened, and at the same time, the difference between the longest distance and the shortest distance. Can be reduced, and the influence on driving can be reduced.

  According to these embodiments, the longest distance between the connection terminal of the common electrode and the driving element can be shortened, and the stability can be improved by driving each driving element stably. In addition, an ink jet recording apparatus can be provided.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet printer, 21 ... Inkjet head, 100 ... Nozzle plate, 101 ... Nozzle, 102 ... Drive element (actuator), 104 ... Diaphragm, 105 ... Insulating film, 106 ... Lower electrode (individual electrode), 106a ... Wiring Part 106b, individual connection terminal part 106c, lower electrode part 106f, side-by-side part 107, upper electrode (common electrode) 107a, wiring part 107b, common connection terminal part 107c, upper electrode part 108 Protective film 109 ... ink repellent film 111 ... piezoelectric film 200 ... pressure chamber structure 201 ... pressure chamber

An inkjet head according to one embodiment includes a nozzle plate, a plurality of actuators, a common electrode, and individual electrodes. The nozzle plate has a plurality of nozzles that eject ink . The plurality of actuators correspond to the individual nozzles. The common electrode is connected to a plurality of actuators and applies a voltage to the actuators. Individual electrodes apply voltages to individual actuators. A plurality of actuators are divided into a plurality of groups, and an individual electrode and a common electrode are provided for each group. A juxtaposed portion in which connection terminals of a plurality of individual electrodes connected to the individual electrodes are arranged in parallel at the end of the nozzle plate is provided. The connection terminal of the common electrode was disposed between the outer portion of the juxtaposed portion of the connection terminal of the individual electrode and between the connection terminals of the individual electrode.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[1] A nozzle plate having a plurality of nozzles and a plurality of actuators corresponding to each of the nozzles, the nozzle plate being connected to the plurality of actuators and applying a voltage to the actuators A plurality of actuators divided into a plurality of groups, the individual electrodes for each group, and the common electrode. A plurality of individual electrode connection terminals connected to the individual electrodes are provided at the end of the nozzle plate, and the common electrode connection terminals are connected to the individual electrode connection terminals. Ink jet heads respectively disposed between the outer portion of the parallel arrangement portions and between the connection terminals of the individual electrodes.
[2] The inkjet head according to [1], wherein the individual electrode passes between the actuators and is drawn out to the connection terminal.
[3] The inkjet head according to [1], wherein each group of the nozzle plates has the same number of individual electrodes.
[4] The inkjet head according to [3], wherein the wiring portion of the individual electrode is disposed on both sides of the individual electrode with respect to a direction in which the connection terminals of the individual electrode are arranged in parallel.
[5] An ink jet recording apparatus having the ink jet head according to any one of [1] to [4].

Claims (5)

A nozzle plate formed with a plurality of nozzles;
A plurality of actuators corresponding to each of the nozzles,
The nozzle plate is connected to a plurality of the actuators, and has a common electrode for applying a voltage to the actuators, and an individual electrode for applying a voltage to each of the actuators,
Dividing the plurality of actuators into a plurality of groups, and arranging the individual electrodes and the common electrodes for each of the groups,
Provided side by side with a plurality of individual electrode connection terminals connected to the individual electrode at the end of the nozzle plate;
The common electrode connection terminal is an ink-jet head that is arranged between an outer portion of a juxtaposed portion of the connection terminals of the individual electrodes and between the connection terminals of the individual electrodes. The inkjet head according to claim 1,
The individual electrode is an ink jet head that passes between the actuators and is drawn out to the connection terminal. The inkjet head according to claim 1,
In each of the groups of the nozzle plates, the number of the individual electrodes is the same. The inkjet head according to claim 3,
The wiring part of the said individual electrode is an inkjet head arrange | positioned at the both sides of the said individual electrode with respect to the juxtaposition direction of the connecting terminal of the said individual electrode.   An ink jet recording apparatus comprising the ink jet head according to claim 1.