JP6024360B2 - Ink jet head and image forming apparatus - Google Patents

Description

  In the present invention, a part of the pressurized liquid chamber communicating with the nozzle hole for ejecting ink droplets is constituted by a vibration plate, and an electromechanical conversion element is provided on the surface of the vibration plate. The present invention relates to an inkjet head that ejects ink droplets and an image forming apparatus including the inkjet head.

  An ink jet recording apparatus such as an ink jet printer includes an ink jet head that discharges droplets onto a recording medium such as paper. The ink-jet head includes a nozzle hole for ejecting ink droplets, an individual liquid chamber that communicates with the nozzle hole, and a pressure generation unit that generates pressure to pressurize the ink in the individual liquid chamber. Ink droplets are ejected from the nozzle holes by pressurizing the ink in the individual liquid chambers with the generated pressure.

  As the pressure generating means of the ink jet head, a piezoelectric type that discharges ink droplets by deforming and displacing a diaphragm forming the wall surface of an individual liquid chamber using an electromechanical transducer such as a piezoelectric element is known. It has been. An inkjet head that ejects ink droplets by such displacement of the electromechanical transducer includes a longitudinal mode in which the electromechanical transducer bonded to the diaphragm is stretched by applying a voltage, and a unimorph between the diaphragm and the electromechanical transducer. Two types of bend modes, which are configured by a mold and generate bending by applying a voltage, have been put into practical use.

  The former uses a laminated electromechanical transducer element in which piezoelectric elements and electrodes are alternately laminated, and is characterized in that a large generated force can be obtained by low voltage driving. However, since the laminated electromechanical transducer is fixed to the base substrate and then cut at intervals equal to the density of the individual liquid chambers is bonded to the diaphragm, the individual liquid chambers need to be side by side. is there. Therefore, in order to increase the density, it is not suitable because cutting in a comb shape or alignment for adhesion becomes difficult.

  On the other hand, the latter is characterized in that the individual liquid chamber, the diaphragm, and the electromechanical transducer (piezoelectric element and upper and lower electrodes sandwiching it) are integrally formed using a thin film deposition technique and a lithography method. is there. Similarly, a thin film deposition technique and a lithography method are used for a wiring for supplying a driving voltage to the electrode and a contact hole for connecting the wiring and the electrode.

  However, the electromechanical conversion element formed by the thin film deposition technique is very thin and has residual stress due to film deposition. Therefore, the rigidity and strength are lower than those of the former, and cracks are likely to occur. In particular, when the contact hole is arranged outside the peripheral wall of the individual liquid chamber, the electromechanical conversion element crosses the peripheral wall. For this reason, there is a problem that stress concentration occurs in a region portion (hereinafter referred to as a “crossing region portion”) that crosses the peripheral wall of the individual liquid chamber of the driven electromechanical transducer. On the other hand, there is a structure in which the contact hole is arranged inside the peripheral wall of the individual liquid chamber, but in this case also, the contact hole has a wiring layer and a wiring protective layer laminated on the electromechanical conversion element, and is not easily displaced. Due to the structure, stress concentration occurs at the end of the contact hole.

  In order to solve these problems, for example, in Patent Document 1, a vibration regulating unit in which the width of the electromechanical conversion element (piezoelectric layer) is changed is provided in the crossing region portion (connection portion) of the electromechanical conversion element. Yes. Specifically, by providing a narrow portion in which the width of the electromechanical conversion element is narrowed in the vibration restricting portion, the stress concentration of the electromechanical conversion element in the narrow portion is reduced. Furthermore, by removing a part of the upper electrode existing between the narrow portions provided in the vicinity of both sides in the vibration restricting portion, the electromechanical transducer has an inactive portion (inactive portion). The stress concentration during driving is alleviated.

  By the way, in Patent Document 1, when a part of the upper electrode existing between the narrow portions is removed, the upper electrode and the piezoelectric element are removed (see paragraph 0124, FIG. 19, etc.). In this way, by removing the piezoelectric element, corners, recesses, and the like are formed in the removed part of the piezoelectric element.

  In this way, if there are corners or recesses in the removed parts of the piezoelectric element, etching residues are likely to remain in these parts during the etching process when manufacturing the piezoelectric element, which may cause current leakage or discharge Prone to cause.

  In other words, it is possible to prevent the occurrence of cracks due to stress concentration during driving by providing a narrow portion with a narrow width of the electromechanical conversion element, but the structure is liable to cause current leakage and discharge, and the reliability of the inkjet head is improved. descend.

  Therefore, the present invention relaxes the stress concentration generated in the region of the electromechanical conversion element that crosses the peripheral wall of the individual liquid chamber during driving, and suppresses the occurrence of current leakage and discharge to ensure high reliability. It is an object of the present invention to provide an inkjet head and an image forming apparatus that can be used.

To achieve the above object, the present invention provides a liquid chamber substrate in which a plurality of individual liquid chambers communicating with nozzle holes from which recording liquid droplets are discharged, and a liquid chamber substrate opposite to the nozzle holes. An electromechanical transducer element formed by laminating a lower electrode on the diaphragm side, a piezoelectric body, and an upper electrode provided in a region via a diaphragm, and on one end side of the upper electrode A lead wire is connected, and the piezoelectric body is vibrated by applying a voltage to the lower electrode and the upper electrode to deform and displace the diaphragm, thereby pressurizing the recording liquid in the individual liquid chamber and In the inkjet head that discharges droplets from nozzle holes, a predetermined range including a region that crosses the boundary between the peripheral wall of the individual liquid chamber and the individual liquid chamber on the side to which the lead-out wiring of the electromechanical conversion element is connected In the upper electrode Electrode removing portion removing only the electrode surface is formed with a plurality, each of the electrodes removed portions of said plurality of which is constituted by the opening, the plurality of electrodes removal unit as characterized by being staggered Yes.

According to the ink jet head of the present invention, in a predetermined range including a region crossing the boundary between the peripheral wall of the individual liquid chamber and the individual liquid chamber on the side to which the lead wiring of the electromechanical conversion element is connected , Since a plurality of electrode removal portions in which only the electrode surface is removed are formed, the electric field region applied to the piezoelectric body from the upper electrode is reduced within this predetermined range. For this reason, when the electromechanical conversion element is driven, the deflection displacement of the piezoelectric body in this predetermined range is reduced, so that the stress concentration in the predetermined range of the piezoelectric body is relaxed, destruction due to cracks and the like is prevented, and current High reliability can be secured by suppressing the occurrence of leakage and discharge.

1 is an exploded perspective view of an inkjet head according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view taken along the line A-A ′ of the assembled ink jet head of FIG. 1. FIG. 2 is a schematic cross-sectional view illustrating an actuator of the ink jet head according to the first embodiment. FIG. 2 is a plan view in which a part of the actuator of the ink jet head in Embodiment 1 is broken. The figure which showed the measurement result of the amount of current leaks per unit area of the actuator of Embodiment 1 of this invention and the actuator of a comparative example. FIG. 9 is a plan view in which a part of the actuator of the inkjet head according to the modification of Embodiment 1 is broken. FIG. 6 is a plan view in which a part of the actuator of the ink jet head in Embodiment 2 is broken. FIG. 10 is a plan view in which a part of the actuator of the ink jet head according to the first modification of Embodiment 2 is broken. FIG. 9 is a plan view in which a part of an actuator of an ink jet head according to a second modification of Embodiment 2 is broken. FIG. 9 is a plan view in which a part of the inkjet head actuator according to the third embodiment is broken. FIG. 10 is a plan view in which a part of the actuator of the inkjet head according to the first modification of Embodiment 3 is broken. FIG. 10 is a plan view with a part broken away showing an actuator of an inkjet head in a second modification of the third embodiment. FIG. 9 is a plan view in which a part of an actuator of an ink jet head according to a third modification of Embodiment 3 is broken. FIG. 6 is a schematic perspective view illustrating a configuration of a main part in an ink jet recording apparatus according to a fourth embodiment of the invention.

Hereinafter, the present invention will be described based on the illustrated embodiments.
<Embodiment 1>
FIG. 1 is an exploded perspective view of an inkjet head according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA ′ of the assembled inkjet head of FIG.

  As shown in these drawings, the inkjet head 1 according to the present embodiment includes a nozzle plate 2 on which nozzle holes 2y, 2m, 2c, and 2k for discharging ink (recording liquid) are formed, and each nozzle hole. The individual liquid chamber forming substrate 101 on which the horizontally long individual liquid chambers 3y, 3m, 3c, and 3k formed in correspondence with each other and partitioned by the flow path partition walls, and the ink in each of the individual liquid chambers 3y to 3k are provided. Are pressed (applying pressure) to eject ink droplets from the nozzle holes 2y to 2k, and the driving IC chip 105a that outputs ejection signals to the actuators 15y to 15k. The heat dissipation members 201a, 20 for transferring heat from the actuator substrate 14 on which the 105b, 105c, 105d are mounted and the drive IC chips 105a-105d. b, 201c, 201d, subframe 102 protecting actuators 15y-15k, common liquid chamber forming substrate 103 having common liquid chambers 4y, 4m, 4c, 4k, and ink supply holes 107y, 107m, 107c, 107k. A formed manifold 104 and a housing 106 into which the manifold 104 is inserted are sequentially stacked.

  As shown in FIGS. 2 and 3, each actuator 15y to 15k includes lower electrodes 11y, 11m, 11c, and 11k that are common electrodes, piezoelectric elements 12y, 12m, 12c, and 12k, and upper electrodes 13y that are individual electrodes. 13m, 13c, 13k. In the above, the subscripts y, m, c, and k correspond to cyan, magenta, yellow, and black colors, respectively.

  The lower electrodes 11y, 11m, 11c, and 11k, the piezoelectric elements 12y, 12m, 12c, and 12k, and the upper electrodes 13y, 13m, 13c, and 13k) of the actuators 15y to 15k are integrally formed by, for example, a well-known sputtering method and a lithoetch method. Is formed.

  FIG. 3 shows the vicinity of the individual liquid chamber 3k of k (black), and the configurations of the individual liquid chambers 3y, 3m, 3c of other colors (y, m, c) are basically the same. Therefore, the following description will be made using the k (black) individual liquid chamber 3.

  As shown in FIG. 3, one end side of the lead wiring 16 is connected to the upper electrode 13 k, and a voltage is applied to the upper electrode 13 k through the lead wiring 16. An insulator layer (not shown) is formed between the lead wiring 16 and the actuator 15k (lower electrode 11k, piezoelectric element 12k, upper electrode 13k), and this insulator layer (not shown) A contact hole 17 (see FIG. 4) for exposing a part of the upper electrode 13k is formed. Through this contact hole 17, the upper electrode 13k and the lead wiring 16 are electrically connected. The lead wiring 16 and the lower electrode 11k are electrically connected to the driving IC chips 105a to 105d.

  In the inkjet head 1 formed as described above, ink as a recording liquid is supplied from the ink supply holes 107y, 107m, 107c, and 107k through the common liquid supply flow path and the like into the individual liquid chambers 3y to 3k. The Then, by applying pulse voltages to the upper electrodes 13y to 13k and the lower electrodes 11y to 11k of the actuators 15y to 15k from the drive IC chips 105a to 105d in a state where the individual liquid chambers 3y to 3k are filled with ink. Then, the piezoelectric elements 12y to 12k are deflected and displaced, and the entire diaphragm 18 in close contact with the actuators 15y to 15k is deformed into a convex shape toward the individual liquid chambers 3y to 3k.

  As a result, the volume of the individual liquid chambers 3y to 3k is reduced and the pressure in the individual liquid chambers 3y to 3k is rapidly increased, so that the ink droplets are transferred from the nozzle holes 2y to 2k to a recording medium (such as paper). It is discharged toward (not shown). Then, by continuously applying a pulse voltage in accordance with the pressure fluctuation period in the individual liquid chambers 3y to 3k, droplets are continuously ejected from the nozzle holes 2y to 2k, and are recorded on a recording medium (not shown). An image (including characters) based on print data from a control unit (not shown) is formed.

  FIG. 4 is a schematic plan view showing the lead wiring 16 side of the actuator 15k (lower electrode 11k, piezoelectric element 12k, upper electrode 13k) shown in FIG. In FIG. 4, a part of the upper electrode 13k is cut away. The same applies to the following embodiments.

  The actuator 15k (lower electrode 11k, piezoelectric element 12k, upper electrode 13k) is provided in a region facing the individual liquid chamber 3k, and is slightly narrower than the width between the peripheral walls 19 facing the horizontally long individual liquid chamber 3k. It is formed with.

  Further, the upper electrode 13k and the lead wiring 16 are electrically connected through a contact hole 17 formed in an insulator layer (not shown). The contact hole 17 is disposed slightly outside the one end 19a of the peripheral wall 19 of the individual liquid chamber 3k. In the present embodiment, the one end 19a of the peripheral wall 19 of the individual liquid chamber 3k and the inside of the individual liquid chamber 3k are arranged on the lead wiring 16 side of the actuator 15k (lower electrode 11k, piezoelectric element 12k, upper electrode 13k). A crossing region portion A (a portion indicated by a black circle) crossing the boundary of

  For this reason, as described in the background art, when the actuator 15k (lower electrode 11k, piezoelectric element 12k, upper electrode 13k) is driven by voltage application, stress concentration occurs in the vicinity of the transverse region A. .

  Therefore, in the first embodiment of the present invention shown in FIG. 4, the upper electrode 13k is formed in a horizontally long shape (horizontal slit shape) along the longitudinal direction (the left-right direction in FIG. 4) of the upper electrode 13k with the transverse region A as the center. ) Electrode removal portion 20 is formed, and the width of the upper electrode 13k in the vicinity of the transverse region portion A is made narrower than other portions. The horizontally long electrode removing portion 20 can be manufactured by a mask design used in a lithography method. Note that the piezoelectric element 12k and the lower electrode 11k of the actuator 15k are not deleted in the entire region.

  Thus, by forming the horizontally long electrode removal portion 20 near the transverse region portion A of the upper electrode 13k, an electric field region applied from the upper electrode 13k to the piezoelectric element 12k near the transverse region portion A can be obtained. Since the actuator 15k is driven, the deflection displacement of the piezoelectric element 12k in the vicinity of the transverse region A is reduced when the actuator 15k is driven. Therefore, the stress concentration in the vicinity of the transverse region A of the piezoelectric element 12k is alleviated, and breakage due to cracks or the like is prevented.

  In addition, since the electrode removal part is formed in the separate liquid chamber 3k side except the crossing area part A vicinity of the upper electrode 13k, in the surrounding wall 19 other than the crossing area part A vicinity of the individual liquid chamber 3k, it is the piezoelectric element 12k. Is flexibly displaced.

Further, since there is no deletion portion to the piezoelectric element 12k, current leakage factors and discharge factors due to the etching process nor the child increase in manufacturing.

  FIG. 5 shows a case where the horizontally elongated electrode removal portion 20 is formed only in the vicinity of the transverse region A of the upper electrode 13k as in Embodiment 1 of the present invention (a in FIG. 5), and the upper electrode 13k as a comparative example. 5 is a measurement result of the amount of current leakage per unit area when the horizontally long electrode removing portion 20 is formed in the vicinity of the transverse region portion A of the piezoelectric element 12k (b in FIG. 5).

  As is apparent from this measurement result, when the electrode removal portion 20 is formed only in the vicinity of the transverse region A of the upper electrode 13k as in Embodiment 1 of the present invention, the amount of current leakage per unit area is larger. It was significantly less.

  As described above, in the present embodiment, by forming the horizontally long electrode removal portion 20 in the vicinity of the transverse region portion A of the upper electrode 13k, the stress concentration generated in the vicinity of the transverse region portion A of the piezoelectric element 12k during driving is concentrated. High reliability can be secured by mitigating and suppressing the occurrence of current leakage and discharge.

  Further, as in a modification of the present embodiment shown in FIG. 6, two horizontally elongated electrode removal portions 20 may be provided in the vicinity of the transverse region A of the upper electrode 13k.

  Thus, by arranging two horizontally long electrode removal portions 20 in the vicinity of the transverse region portion A of the upper electrode 13k, the upper electrode 13k is applied to the piezoelectric element 12k in the vicinity of the transverse region portion A. Since the electric field region is further reduced, the flexural displacement of the piezoelectric element 12k near the crossing region portion A is further reduced when the actuator 15k is driven. Therefore, the stress concentration in the vicinity of the transverse region A of the piezoelectric element 12k is further relaxed.

  If a large number of transverse slit-shaped electrode removing portions 20 are arranged in the vicinity of the transverse region portion A of the upper electrode 13k, the stress concentration in the vicinity of the transverse region portion A of the piezoelectric element 12k can be dispersed. However, when the pitch of each electrode removal portion 20 is narrowed, the electric field in the piezoelectric element 12k tends to increase as it goes from the upper electrode 13k to the lower electrode 11k. The whole may be driven. Therefore, as shown in FIG. 6, it is preferable to arrange up to two electrode removal portions 20 in the vicinity of the crossing region portion A of the upper electrode 13k.

  In the first embodiment, the width of the horizontally long electrode removing portion 20 is constant, but the width of the electrode removing portion 20 may be gradually narrowed toward the individual liquid chamber 3k side. As a result, the driving method of the actuator 15k can gradually increase the vibration in the longitudinal direction of the individual liquid chamber 3k, so that the stress distribution near the transverse region A is further smoothed and the generation of cracks is suppressed. be able to.

<Embodiment 2>
In the first embodiment, the horizontally elongated electrode removal portion 20 is formed in the vicinity of the transverse region A of the upper electrode 13k along the longitudinal direction of the upper electrode 13k. However, as shown in FIG. In Embodiment 2 of the invention, the upper electrode 13k of the actuator 15k has a vertically long shape (vertical slit shape) along the width direction (vertical direction in FIG. 7) of the upper electrode 13k on both sides centering on the transverse region A. A plurality of electrode removal portions 21 are formed at a predetermined interval (four in FIG. 7). Each electrode removal portion 21 is not formed at a position overlapping the crossing region portion A. Other configurations of the inkjet head are the same as those in the first embodiment.

  The vertically long electrode removing portion 21 can be manufactured by a mask design used in a lithography method. Note that the piezoelectric element 12k and the lower electrode 11k of the actuator 15k are not deleted in the entire region.

  When an electric field is applied to the piezoelectric element 12k when the actuator 15k is driven, the piezoelectric element 12k contracts isotropically in the direction orthogonal to the electric field direction (the left-right direction in FIG. 7). Furthermore, by forming the vertically elongated electrode removal portion 21 in the vicinity of the transverse region portion A of the upper electrode 13k, the stress concentration generated in the vicinity of the transverse region portion A in the longitudinal direction of the piezoelectric element 12k at the time of driving is relieved, In addition, high reliability can be secured by suppressing the occurrence of current leakage and discharge.

  Further, as in the first modification of the present embodiment shown in FIG. 8, a vertically elongated electrode removal portion 21a in the width direction (vertical direction in FIG. 8) in accordance with the position of the transverse region A of the upper electrode 13k. Further, vertically elongated electrode removal portions 21b and 21c may be formed on both sides thereof.

  Thus, by forming the vertically elongated electrode removal portion 21a in the width direction (vertical direction in FIG. 8) in accordance with the position of the transverse region portion A of the upper electrode 13k, the short direction of the piezoelectric element 12k during driving The stress concentration in the vicinity of the cross-sectional area portion A generated in FIG.

  Further, in the second modification of the present embodiment shown in FIG. 9, a part of each of the electrode removal portions 21a, 21b, 21c of the upper electrode 13k of the first modification of the second embodiment shown in FIG. The upper electrode 13k is changed to extend in the longitudinal direction.

  In this way, by changing a part of each electrode removal portion 21a, 21b, 21c of the upper electrode 13k so as to extend in the longitudinal direction of the upper electrode 13k, the transverse region portion of the piezoelectric element 12k during driving The stress distribution in the vicinity of A becomes smooth, and the stress concentration can be relaxed.

<Embodiment 3>
In the first embodiment, the horizontally elongated electrode removing portion 20 is formed in the vicinity of the transverse region portion A of the upper electrode 13k along the longitudinal direction of the upper electrode 13k. However, as shown in FIG. In the third embodiment of the invention, the upper electrode 13k of the actuator 15k has a configuration in which a plurality (eight in FIG. 7) of electrode removal portions 22 are formed in a lattice shape on both sides of the crossing region portion A as a center. Each electrode removal part 22 is not formed in the position which overlaps the crossing area | region part A. As shown in FIG. Other configurations of the inkjet head are the same as those in the first embodiment.

  Each electrode removal part 22 formed in this lattice shape can be produced by a mask design used in the lithography method. Note that the piezoelectric element 12k and the lower electrode 11k of the actuator 15k are not deleted in the entire region.

  As described above, the configuration in which the electrode removal portions 22 are formed in a lattice pattern in the vicinity of the transverse region portion A of the upper electrode 13k causes the stress in the vicinity of the transverse region portion A of the piezoelectric element 12k to be uniformly dispersed during driving. Thus, stress concentration can be reduced.

  Further, as in the first modification of the present embodiment shown in FIG. 11, a plurality of electrodes (12 in FIG. 11) are removed on both sides of the upper electrode 13k of the actuator 15k with the transverse region portion A as the center. It is the structure which formed the part 22 in zigzag form. Each electrode removal part 22 is not formed in the position which overlaps the crossing area | region part A. As shown in FIG.

  As described above, the electrode removal portions 22 are formed in a staggered manner in the vicinity of the crossing region portion A of the upper electrode 13k, so that the stress in the vicinity of the crossing region portion A of the piezoelectric element 12k is more evenly distributed during driving. Therefore, the stress concentration can be reduced.

  In addition, since the size of one electrode removal portion 22 can be reduced by forming the electrode removal portion 22 in a lattice shape or a zigzag shape, the upper electrode 13k and the piezoelectric element 12k in the vicinity of the transverse region portion A are used. Stable adhesion can be maintained by suppressing a decrease in the adhesion area.

  Further, as in the second and third modifications of the present embodiment shown in FIGS. 12 and 13, respectively, the electrode removal portions 22 are arranged in a lattice shape (see FIG. 12) or in accordance with the position of the connection portion A of the upper electrode 13k. By forming the zigzag pattern (see FIG. 13), stress concentration in the vicinity of the transverse region A occurring in the short direction of the piezoelectric element 12k during driving can be reduced.

<Embodiment 4>
FIG. 14 is a schematic perspective view showing a configuration of a main part in an ink jet recording apparatus as an image forming apparatus according to Embodiment 4 of the present invention. In this ink jet recording apparatus, the ink jet head according to the first embodiment (or any one of the second and third embodiments) is mounted.

  As shown in FIG. 14, this inkjet recording apparatus 40 includes an apparatus main body 41 having a carriage 42 movable in the scanning direction, the inkjet head 1 mounted on the carriage 42, and an ink cartridge for supplying ink to the inkjet head 1. A printing mechanism 44 including 43 and the like is accommodated.

  The printing mechanism 44 holds a main guide rod 48 and a sub guide rod 49, which are guide members horizontally mounted on left and right side plates (not shown), and the carriage 42 slidably in the main scanning direction. The carriage 42 has an inkjet head 1 that ejects ink droplets of yellow (Y), cyan (C), magenta (M), and black (K), and a direction in which a plurality of nozzle holes intersect the main scanning direction. Are mounted so that the ink droplet ejection direction is directed downward in FIG. In addition, each ink cartridge 43 for supplying ink of each color to the inkjet head 1 is replaceably mounted on the carriage 42.

  The carriage 42 is slidably fitted to the main guide rod 48 on the rear side (paper conveyance downstream side), and is slidably mounted on the sub guide rod 49 on the front side (paper conveyance upstream side). In order to move and scan the carriage 42 in the main scanning direction, a timing belt 53 is stretched between a driving pulley 51 and a driven pulley 52 that are rotationally driven by a motor 50, and the timing belt 53 is attached to the carriage 42. It is fixed. The carriage 42 is driven to reciprocate by forward and reverse rotation of the motor 50.

  During recording by the above-described inkjet recording apparatus 40, the inkjet head 1 is driven in accordance with an input image signal while moving the carriage 42, thereby ejecting ink onto the fed paper to form one line. Recording is performed, and then the next line is recorded after the sheet is conveyed by a predetermined amount. Upon receiving a recording end signal or a signal that the trailing edge of the sheet has reached the recording area, the recording operation is terminated, and the sheet is discharged onto the discharge tray.

  As described above, since the inkjet recording apparatus 40 according to the present embodiment includes the highly reliable inkjet head 1 as described above, the reliability of the entire inkjet recording apparatus 40 can be improved. Therefore, stable ink ejection characteristics can be obtained over a long period of time, and a high-quality image can be recorded.

DESCRIPTION OF SYMBOLS 1 Inkjet head 3y-3k Individual liquid chamber 11y-11k Lower electrode 12y-12k Piezoelectric element (piezoelectric body)
13y-13k Upper electrode 15y-15k Actuator (electromechanical transducer)
16 Lead-out wiring 20, 21, 21a, 21b, 21c, 22 Electrode removal unit 40 Inkjet recording apparatus (image forming apparatus)
42 Carriage A Crossing area (crossing area)

Japanese Patent No. 3414227

Claims (3)

A liquid chamber substrate formed with a plurality of individual liquid chambers communicating with nozzle holes from which recording liquid droplets are discharged;
An electromechanical conversion element configured by laminating a lower electrode, a piezoelectric body, and an upper electrode on the vibration plate side provided through a vibration plate in a region opposite to the nozzle hole of the liquid chamber substrate. In addition, a lead-out wiring is connected to one end side of the upper electrode, and the piezoelectric body is vibrated by applying a voltage to the lower electrode and the upper electrode to deform and displace the diaphragm. In an inkjet head that pressurizes the recording liquid in the individual liquid chamber and discharges droplets from the nozzle holes,
In a predetermined range including a region crossing a boundary between the peripheral wall of the individual liquid chamber and the individual liquid chamber on the side where the lead-out wiring of the electromechanical conversion element is connected, only the electrode surface of the upper electrode is removed. electrode removing portion is formed with a plurality, each of the electrodes removed portions of said plurality of which is constituted by the opening, the plurality of electrodes removal section ink jet head is characterized in that it is arranged in a zigzag pattern. Wherein the plurality of part of the electrode removed portion, the ink-jet head according to claim 1, characterized in that located on a region across the boundary. In an image forming apparatus for recording on a recording medium by discharging droplets from nozzle holes of an inkjet head,
Image forming apparatus, wherein said ink-jet head is an inkjet head according to claim 1 or 2.