JP6686635B2 - INKJET HEAD, METHOD FOR MANUFACTURING THE SAME, AND INKJET PRINTER - Google Patents

Description

  The present invention relates to an inkjet head that ejects ink, a method for manufacturing the inkjet head, and an inkjet printer including the inkjet head.

  2. Description of the Related Art Conventionally, an inkjet printer including an inkjet head having a plurality of channels for ejecting liquid ink has been known. A two-dimensional image can be output to the recording medium by controlling the ejection of ink while moving the inkjet head relative to the recording medium such as paper or cloth. The ink can be ejected by using a pressure type actuator (piezoelectric type, electrostatic type, thermal deformation, etc.) or by generating bubbles in the ink in the tube by heat. Among them, the piezoelectric actuator has advantages such as high output, modulation, high response, and ink selection, and has been widely used in recent years.

Perovskite-type metal oxides such as barium titanate (BaTiO ₃ and lead zirconate titanate (Pb (Zr, Ti) O ₃ )) are widely used for piezoelectric bodies used in piezoelectric actuators. The above-mentioned piezoelectric body includes a bulk piezoelectric body that is fired like a ceramic tile and a thin film piezoelectric body (piezoelectric thin film) that is formed on a substrate. Whether to use may be selected according to the application.

  FIG. 23A is a plan view showing a schematic configuration of an inkjet head 200 including a conventional piezoelectric actuator, and FIG. 23B is a sectional view taken along the line M-M ′ in FIG. 23A. The inkjet head 200 is configured by arranging the actuator 101 on one surface side of the support substrate 100 having the pressure chambers 100a and the nozzle substrate 102 on the other surface side. Nozzles 102a, which are ejection holes for controlling the amount of liquid droplets, are formed on the nozzle substrate 102. The nozzle 102a communicates with the pressure chamber 100a.

  The actuator 101 is configured by laminating a vibrating plate (driven film) 201, an insulating layer 202, a lower electrode 203, a piezoelectric layer 204, and an upper electrode 205 in this order from the supporting substrate 100 side. The lower electrode 203 and the upper electrode 205 are connected to the drive circuit 206. Further, an ink supply port 301 for supplying ink from a storage chamber (not shown) to the pressure chamber 100a is formed so as to penetrate the vibration plate 201 and the insulating layer 202. The ink supply port 301 communicates with the pressure chamber 100a via a sub chamber 100b formed in the support substrate 100 side by side with the pressure chamber 100a.

  In the above structure, when a voltage is applied to the lower electrode 203 and the upper electrode 205 from the drive circuit 206, the piezoelectric layer 204 expands and contracts in the direction perpendicular to the thickness direction (direction parallel to the surface of the support substrate 100). Then, due to the difference in length between the piezoelectric layer 204 and the diaphragm 201, a curvature is generated in the diaphragm 201, and the diaphragm 201 is displaced (curved) in the thickness direction. By such a vertical movement of the actuator 101, pressure can be applied to the ink introduced into the pressure chamber 100a to eject an ink droplet from the nozzle 102a.

  In this way, by combining the actuator 101, the support substrate 100, and the nozzle substrate 102, an ink channel (ink ejection portion) is formed. The ink jet head 200 is configured by arranging such ink channels vertically and horizontally.

  In addition, as another form of an inkjet head (hereinafter, also simply referred to as a head), a configuration in which a wiring substrate is arranged to face an inkjet substrate is also known. The inkjet substrate is a head substrate (flow passage forming substrate) including a pressure chamber, a vibrating plate, and a nozzle, a piezoelectric body for applying pressure to ink in the pressure chamber, an electrode (individual electrode) for driving the piezoelectric body. (Upper electrode), common electrode (lower electrode)), and wiring (first wiring) drawn from the individual electrode. The wiring board has wiring (second wiring) for supplying a drive signal to the individual electrodes. By electrically connecting the first wiring of the inkjet substrate and the second wiring of the wiring substrate, a drive signal is supplied from the wiring substrate side to the inkjet substrate side. By driving the piezoelectric body based on the drive signal, pressure is applied to the ink in the pressure chamber, and the ink is ejected from the nozzle.

  In recent years, various configurations have been proposed in which the wiring substrate is arranged so as to face the inkjet substrate as described above, and an attempt is made to reduce the size of the head. For example, in Patent Document 1, in the inkjet substrate, an inclined surface inclined with respect to the surface direction of the diaphragm is provided outside the pressure chamber, and the first wiring (connection terminal) and the second wiring (connection terminal) are respectively formed as described above. It is disclosed that the structure is pulled out to an inclined surface and connected there. In this configuration, while securing a certain area or more of the region where each connection terminal contacts on the inclined surface, it is possible to reduce the projected area of the region when viewed from the direction orthogonal to the diaphragm, so that the device It is believed that it can be miniaturized.

  Further, for example, Patent Document 2 discloses a configuration in which an inkjet substrate and a wiring substrate are arranged to face each other with a substrate supporting portion interposed therebetween. The substrate supporting portion is composed of a plate-shaped member that is erected on the outer surface of the pressure chamber in the inkjet substrate, and has a first wiring on the inkjet substrate side and a second wiring on the wiring substrate side on its side surface. A COF (Chip on Film) substrate for electrically connecting to the wiring is supported. With this configuration, it is considered that the wiring of each substrate can be easily connected by using the substrate supporting portion and that the substrate supporting portion does not spread in the area direction of the head, so that it is possible to prevent the head itself from increasing in size. ing.

JP-A-2014-162085 (see claim 1, paragraphs [0007], [0009], [0064], FIG. 4 and the like). JP, 2010-099872, A (refer to claims 1 to 3, paragraphs [0007] to [0009], [0027] to [0029], FIG. 1, FIG. 2 and the like).

  By the way, in the configuration in which the wiring substrate is arranged to face the inkjet substrate, the connection portion is made of resin for the purpose of improving the strength and reliability of the connection portion between the first wiring of the inkjet substrate and the second wiring of the wiring substrate. The connection form of sealing with is becoming mainstream. The method of supplying the resin to the connection portion includes a pre-supply method and a post-supply method. In the pre-supply method, the resin is first supplied onto the inkjet substrate, and then the wiring substrate is pressed against the inkjet substrate through the resin to connect the connection terminals of the first wiring and the second wiring, This is a method of curing the above resin. On the other hand, the post-supply method is a method of supplying (filling) the resin to the connection portion after connecting the connection terminals of the inkjet board and the wiring board.

  When the gap between the two members connected via the resin is as small as several μm, for example, it is difficult to supply the resin to the gap by the post-supply system, and thus the pre-supply system is often adopted. The above-mentioned Patent Documents 1 and 2 both employ the pre-supply method. More specifically, in Patent Document 1, an anisotropic conductive adhesive is arranged so as to cover the connection terminals drawn out on the inclined surface of the inkjet substrate, and then the connection terminals on the wiring substrate side are connected to the inkjet substrate side while heating. By pressing, the connection terminals are electrically connected to each other and the two substrates are mechanically joined. Further, in Patent Document 2, an anisotropic conductive adhesive is arranged between the COF located on the side surface of the substrate support part and the inkjet substrate, and then the substrate support part is pressed against the inkjet substrate side to thereby form a COF substrate. Is electrically connected to the inkjet substrate.

  In the pre-supply method, as described above, it is necessary to press (press, press) the wiring board and the board supporting portion after supplying the resin onto the inkjet board. Therefore, in Patent Documents 1 and 2, each connection terminal is positioned on a region of the inkjet substrate having high strength, that is, on a region outside the ink flow path of the inkjet substrate, and the wiring substrate or the like is pressed to connect each connection. I am trying to connect the terminals.

  However, in the configuration in which each connection terminal is located on the area outside the flow path in the inkjet substrate as in Patent Documents 1 and 2, providing the circulation flow path in the inkjet substrate requires enlarging the inkjet substrate. There is a problem that it becomes difficult to avoid increasing the size of the head. The circulation flow path is a flow formed on the inkjet substrate to circulate non-ejection ink other than the ink ejected from the nozzle in order to improve the ink ejection performance by removing bubbles and foreign matters in the pressure chamber. It is a road. When the circulation flow channel is provided in the inkjet substrate, the ratio of the flow channel of the ink in the inkjet substrate increases, and conversely, the ratio of the portion other than the flow channel decreases. Therefore, in order to position each connection terminal on a region outside the flow path in the inkjet substrate while providing a circulation flow path in the inkjet substrate, the inkjet substrate is required to have a certain contact area of each connection terminal or more. It is necessary to widen the region outside the flow path at. Therefore, the size of the inkjet substrate must be increased, and the size of the head itself is increased.

  Note that, in order to avoid an increase in the size of the inkjet substrate and the head, for example, if each connection terminal is positioned on the inkjet substrate at a position overlapping the circulation channel, there is a concern that the reliability of the head may be reduced. It More specifically, in the inkjet substrate, the wall (upper wall) that covers the circulation flow path from the wiring board side is thinner than the outer wall (side wall) of the circulation flow path and has a weaker strength, so that the flexible region is easily bent when pressed. Make up. Therefore, the position overlapping the circulation channel on the inkjet substrate, that is, the resin is supplied onto the flexible region, and then when the wiring substrate is pressed, the flexible region may bend and break due to stress concentration, The reliability of the head is reduced. Therefore, in the configuration in which the circulation channel is provided on the inkjet substrate, it is desired to ensure the reliability of the head and to avoid an increase in the size of the head.

  The present invention has been made to solve the above problems, and an object of the present invention is to avoid the increase in the size of the head while ensuring the reliability of the head even when the circulation channel is provided in the inkjet substrate. It is an object of the present invention to provide an inkjet head capable of achieving the above, a manufacturing method thereof, and an inkjet printer equipped with the inkjet head.

  An inkjet head according to one aspect of the present invention is for adhering an inkjet substrate that ejects ink based on a drive signal, a wiring substrate that supplies the drive signal to the inkjet substrate, and the inkjet substrate and the wiring substrate. And an ink jet head including: a pressure chamber for accommodating ink; a nozzle communicating with the pressure chamber; and non-ejection ink other than ink ejected from the nozzle. A head substrate having a circulation channel for controlling the circulation channel and a flexible region covering the circulation channel from the wiring substrate side; and a piezoelectric body supported by the head substrate and applying a pressure to the ink in the pressure chamber. A wiring line base including an individual electrode for driving the piezoelectric body, and a first wiring electrically connected to the individual electrode. Includes a second wiring for supplying the drive signal to the individual electrode, and a region on the inkjet substrate that overlaps at least a part of the circulation flow channel is defined as a first region. When the region overlapping the outside of the road is defined as the second region, the adhesive member is configured such that the first wiring and the second wiring are electrically connected at least in the first region. The inkjet substrate and the wiring substrate are bonded to each other in both the first region and the second region.

  A method for manufacturing an inkjet head according to another aspect of the present invention includes a bonding step of bonding an inkjet substrate that ejects ink based on a drive signal and a wiring substrate that supplies the drive signal to the inkjet substrate with an adhesive member. In the method of manufacturing an inkjet head, the inkjet substrate has a pressure chamber for containing ink, a nozzle communicating with the pressure chamber, and a circulation for circulating non-ejection ink other than ink ejected from the nozzle. A head substrate having a flow channel and a flexible region covering the circulation flow channel from the wiring substrate side; a piezoelectric body supported by the head substrate and applying a pressure to ink in the pressure chamber; An individual electrode for driving the first electrode and a first wiring electrically connected to the individual electrode, wherein the wiring substrate is the individual electrode. The bonding step includes a second wiring for supplying the drive signal, and the bonding step includes a first region on the inkjet substrate, the first region overlapping at least a part of the circulation channel, and the outside of the circulation channel. A first step of disposing the adhesive member in a second region that overlaps with the first region; and a first step of relatively pressing the wiring substrate against the inkjet substrate via the adhesive member. The adhesive member that electrically connects the wiring and the second wiring in at least the first region and positions the inkjet substrate and the wiring substrate in the first region and the second region. And a second step of adhering by.

  In the above configuration, the adhesive member may be located on the inkjet substrate in the first region and the second regions on both sides of the first region. Further, in the above manufacturing method, in the first step, the adhesive member is provided on the inkjet substrate in the first region and the second regions on both sides of the first region. You may arrange.

  In the above configuration, the adhesive member may be located on the inkjet substrate in the first region and the second region on one side of the first region. Further, in the above manufacturing method, in the first step, the adhesive member is provided on the inkjet substrate in the first region and the second region on one side of the first region. You may arrange.

  In the above structure, the adhesive member may include an anisotropic conductive adhesive having conductive particles, and the anisotropic conductive adhesive may be located in the first region. Further, in the above-mentioned manufacturing method, the adhesive member includes an anisotropic conductive adhesive having conductive particles, and in the first step, the anisotropic conductive adhesive is arranged in the first region. Good.

  In the above structure, the anisotropic conductive adhesive may be further located in the second region. Further, in the above-mentioned manufacturing method, in the first step, the anisotropic conductive adhesive may be further arranged in the second region.

  In the above configuration, the anisotropic conductive adhesive may be continuously located on the inkjet substrate from the first region to the second region. Further, in the above manufacturing method, in the first step, the anisotropic conductive adhesive may be arranged so as to be continuous from the first region to the second region on the inkjet substrate. Good.

  In the above configuration and manufacturing method, the anisotropic conductive adhesive may be an anisotropic conductive film or an anisotropic conductive paste.

  In the above configuration, the adhesive member may include a non-conductive adhesive, and the non-conductive adhesive may be located in the second region. Further, in the above manufacturing method, the adhesive member may further include a non-conductive adhesive, and in the first step, the non-conductive adhesive may be arranged in the second region.

  In the above configuration, the adhesive member includes a non-conductive adhesive, the first wiring and the second wiring are in direct contact with each other at least in the first region, and the non-conductive adhesive is used. The agent may be located around the first wiring and the second wiring which are in direct contact with each other in the first region, and may bond the inkjet substrate and the wiring substrate. Further, in the above-mentioned manufacturing method, the adhesive member includes a non-conductive adhesive, and in the first step, the non-conductive adhesive is arranged in the first region, and the second step. Then, by relatively pressing the wiring substrate against the inkjet substrate, the first wiring and the second wiring are brought into direct contact with each other at least in the first region, and in the first region, The inkjet board and the wiring board may be bonded to each other by the non-conductive adhesive located around the first wiring and the second wiring that are in direct contact with each other.

  In the above structure, the non-conductive adhesive may be further located in the second region. Further, in the above-mentioned manufacturing method, in the first step, the non-conductive adhesive may be further arranged in the second region.

  In the above configuration, the non-conductive adhesive may be continuously located on the inkjet substrate from the first region to the second region. Further, in the above manufacturing method, in the first step, the non-conductive adhesive may be arranged on the inkjet substrate so as to be continuous from the first region to the second region. .

  In the above configuration and the above manufacturing method, the non-conductive adhesive may be a non-conductive film or a non-conductive paste.

  In the above configuration and manufacturing method, the head substrate has a plurality of the pressure chambers, and the circulation flow path is a common flow path that communicates with each of the pressure chambers and circulates the non-ejection ink. It may be.

  In the above configuration, the first wiring includes a first connection terminal at a position overlapping at least a part of the circulation flow path, and the second wiring at least a part of the circulation flow path. The first connection terminal and the second connection terminal may be electrically connected to each other, including a second connection terminal in a position overlapping with. Further, in the above-described manufacturing method, in the second step, the first connection terminal included in the first wiring and the second connection terminal are included by relatively pressing the wiring board against the inkjet board. The second connection terminal included in the wiring may be electrically connected at a position overlapping at least a part of the circulation channel.

  An inkjet printer according to yet another aspect of the present invention includes the inkjet head described above, and ejects ink from the inkjet head toward a recording medium.

  According to the configuration and the manufacturing method described above, it is possible to avoid the increase in the size of the head while ensuring the reliability of the head even when the circulation channel is provided in the inkjet substrate.

FIG. 1 is an explanatory diagram showing a schematic configuration of an inkjet printer according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a schematic configuration of an inkjet head included in the inkjet printer. FIG. 3 is a plan view of the inkjet head. It is sectional drawing which shows the manufacturing process of the inkjet substrate of the said inkjet head typically. FIG. 6 is a cross-sectional view schematically showing a continuation of the manufacturing process of the inkjet substrate. FIG. 3 is a plan view of the inkjet substrate. It is a sectional view of the above-mentioned ink-jet board which arranged an adhesion member. FIG. 7B is a plan view of the inkjet substrate of FIG. 7A. FIG. 4 is a cross-sectional view of the wiring board and the inkjet board after alignment. FIG. 9 is a plan view of the wiring board and the inkjet board of FIG. 8. It is sectional drawing which shows typically a mode when the said wiring board is pressure-bonded to the said inkjet board. It is sectional drawing which shows the other structure of the said inkjet head. It is sectional drawing which shows another structure of the said inkjet head. It is sectional drawing which shows another structure of the said inkjet head. It is sectional drawing which shows another structure of the said inkjet head. It is sectional drawing which shows another structure of the said inkjet head. FIG. 15B is a sectional view taken along the line E-E ′ in FIG. 15A. FIG. 15B is a sectional view taken along the line F-F ′ in FIG. 15A. FIG. 15B is a part of a sectional view taken along the line G-G ′ in FIG. 15A. It is sectional drawing which shows another structure of the said inkjet head. It is sectional drawing which shows another structure of the said inkjet head. It is a top view which shows the other structure of the said inkjet substrate. FIG. 20 is a perspective view including an H-H ′ cross section of the inkjet substrate of FIG. 19. It is sectional drawing which expands and shows the J section of FIG. It is sectional drawing which shows the detail of the manufacturing process of the body plate with a piezoelectric element. It is a top view which shows the schematic structure of the conventional inkjet head. FIG. 23B is a sectional view taken along the line M-M ′ in FIG. 23A.

  EMBODIMENT OF THE INVENTION It will be as follows if one Embodiment of this invention is demonstrated based on drawing. In this specification, when the numerical range is described as A to B, the numerical range includes the lower limit A and the upper limit B.

[Configuration of inkjet printer]
FIG. 1 is an explanatory diagram showing a schematic configuration of the inkjet printer 1 of the present embodiment. The inkjet printer 1 forms an image on the recording medium P by ejecting ink from the inkjet head 2 toward the recording medium P. The inkjet printer 1 is composed of, for example, a so-called line head type inkjet recording device in which the inkjet heads 2 are linearly provided in the width direction of the recording medium.

  The inkjet printer 1 includes the inkjet head 2, the feeding roll 3, the winding roll 4, two back rolls 5 and 5, an intermediate tank 6, a liquid feed pump 7, a storage tank 8, and a fixing mechanism. 9 and 9.

  The inkjet head 2 ejects ink toward the recording medium P, and in the present embodiment, is arranged at a position facing the recording medium P conveyed from one back roll 5 toward the fixing mechanism 9. There is. A plurality of inkjet heads 2 may be provided corresponding to inks of different colors (for example, yellow, magenta, cyan, and black).

  The pay-out roll 3, the winding roll 4, and the back rolls 5 are members each having a columnar shape that is rotatable around an axis. The delivery roll 3 is a roll that delivers the long recording medium P wound around the circumferential surface in multiple layers toward a position facing the inkjet head 2. The delivery roll 3 delivers the recording medium P in the X direction of FIG. 1 by being rotated by a drive unit (not shown) such as a motor.

  The take-up roll 4 is taken out from the take-up roll 3 and takes up the recording medium P on which the ink is ejected by the inkjet head 2 on the circumferential surface.

  Each back roll 5 is arranged between the pay-out roll 3 and the winding roll 4. The one back roll 5 located on the upstream side in the transport direction of the recording medium P is located at a position facing the inkjet head 2 while supporting the recording medium P fed by the feeding roll 3 by winding it around a part of the peripheral surface. Carry towards. The other back roll 5 winds the recording medium P from a position facing the inkjet head 2 toward the take-up roll 4 while winding the recording medium P around a part of the peripheral surface and supporting the recording medium P.

  The intermediate tank 6 temporarily stores the ink supplied from the storage tank 8. The intermediate tank 6 is connected to the ink tube 10 a, adjusts the back pressure of the ink in the inkjet head 2, and supplies the ink to the inkjet head 2.

  The liquid feed pump 7 supplies the ink stored in the storage tank 8 to the intermediate tank 6, and is arranged in the middle of the supply pipe 10b. The ink stored in the storage tank 8 is pumped up by the liquid feed pump 7 and supplied to the intermediate tank 6 via the supply pipe 10b.

  The fixing mechanism 9 fixes the ink ejected onto the recording medium P by the inkjet head 2 onto the recording medium P. The fixing mechanism 9 is composed of a heater for heating and fixing the ejected ink on the recording medium P, a UV lamp for curing the ink by irradiating the ejected ink with UV (ultraviolet rays), and the like. There is.

  In the above configuration, the recording medium P fed from the feeding roll 3 is conveyed to a position facing the inkjet head 2 by the back roll 5, and ink is ejected from the inkjet head 2 to the recording medium P. After that, the ink ejected onto the recording medium P is fixed by the fixing mechanism 9, and the recording medium P after the ink is fixed is taken up by the take-up roll 4. As described above, in the line-head inkjet printer 1, ink is ejected while the recording medium P is being conveyed while the inkjet head 2 is stationary, and an image is formed on the recording medium P.

  The inkjet printer 1 may be configured to form an image on a recording medium by a serial head method. The serial head method is a method of forming an image by moving an inkjet head in a direction orthogonal to the carrying direction of a recording medium and ejecting ink while carrying the recording medium. In this case, the inkjet head moves in the width direction of the recording medium while being supported by a structure such as a carriage. Further, as the recording medium, other than the long one, a sheet-like one which is cut in advance to a predetermined size (shape) may be used.

[Structure of inkjet head]
Next, the configuration of the inkjet head 2 described above will be described. 2 is a cross-sectional view showing a schematic configuration of the inkjet head 2, and FIG. 3 is a plan view of the inkjet head 2. The sectional view of FIG. 2 corresponds to the sectional view taken along the line AA ′ of FIG. Further, in FIG. 3, the lower electrode 31 described later is omitted for convenience. The inkjet head 2 is configured by adhering an inkjet substrate 11 and a wiring substrate 51 with an adhesive member 61.

(Inkjet substrate)
The inkjet substrate 11 is a substrate (also referred to as an inkjet head chip) that ejects ink based on a drive signal, and includes a head substrate 12 and a piezoelectric element 13.

《Head substrate》
The head substrate 12 is configured by bonding a body plate 21, an intermediate plate 22, and a nozzle plate 23 together. The body plate 21 is formed of a semiconductor substrate made of single crystal Si (silicon) or an SOI (Silicon on Insulator) substrate. The SOI substrate is formed by joining two Si substrates with each other through an oxide film. The body plate 21 is adjusted to have a thickness of about 100 to 300 μm, for example, by polishing a substrate having a thickness of about 750 μm. The thickness of the body plate 21 may be appropriately adjusted depending on the device to which it is applied.

  The body plate 21 is provided with a plurality of pressure chambers 21a for accommodating ink and an ink supply port 21b corresponding to each pressure chamber 21a. The ink supplied from the intermediate tank 6 (see FIG. 1) is supplied to the pressure chamber 21a via the ink supply port 21b. The ink supplied to the pressure chamber 21a may be pigment ink or dye ink. An upper wall of the pressure chamber 21a (a wall located on the piezoelectric element 13 side) in the body plate 21 constitutes a vibration plate 21c that is displaced (vibrated) along with driving (expansion and contraction) of a piezoelectric body 32 described later. A thermal oxide film 21e (see FIG. 22) such as silicon oxide may be provided on the diaphragm 21c for the purpose of protecting and insulating the body plate 21.

  The intermediate plate 22 is made of, for example, a glass substrate having a thickness of about 100 to 300 μm, and is a communication passage 22a communicating with the pressure chamber 21a of the body plate 21, and a circulation flow path for circulating the non-ejection ink. It has a common circulation channel 22b. The common circulation flow path 22b communicates with the intermediate tank 6 through the ink discharge port 25 (see FIG. 3). The width (length in the left-right direction in FIG. 2) of the common circulation channel 22b is, for example, about 1.5 mm. The intermediate plate 22 is bonded to the body plate 21 by an adhesive, for example, but may be bonded by anodic bonding.

  The nozzle plate 23 is made of, for example, a Si substrate having a thickness of about 100 to 300 μm, and has a nozzle 23a and an individual flow path 23b. The nozzle 23a is a discharge hole for discharging the ink in the pressure chamber 21a to the outside, and communicates with the pressure chamber 21a via a communication passage 22a. The individual flow path 23b is provided so as to be branched from the flow path of the ink flowing from the pressure chamber 21a to the nozzle 23a via the communication path 22a, and is connected to the common circulation flow path 22b.

  The ink that has flowed into the common circulation flow path 22b via the individual flow path 23b is returned to the intermediate tank 6 by a pump or the like, and is supplied to the pressure chamber 21a again. This makes it possible to remove bubbles and foreign matter in the pressure chamber 21a and improve the ink ejection performance.

  Here, the ink supplied to the common circulation channel 22b includes not only the ink that flows from the pressure chamber 21a through the individual channel 23b but also the ink that is drawn from the nozzle 23a when the ink is not ejected. In any case, these inks are not ejected from the nozzle 23a. From this, it can be said that the common circulation flow path 22b is a flow path for circulating the non-ejection ink other than the ink ejected from the nozzle 23a. The common circulation channel 22b is a circulation channel (common channel) common to each pressure chamber 21a, which communicates with each pressure chamber 21a and circulates non-ejection ink.

  The above-mentioned common circulation flow path 22b is covered with the body plate 21 from the wiring board 51 side, as shown in FIG. With this configuration, in the head substrate 12, the thickness of the region that covers the common circulation flow channel 22b from the wiring substrate 51 side is the thickness of only the body plate 21, whereas the thickness of the region outside the common circulation flow channel 22b. Includes the thickness of the body plate 21 and the thickness of the intermediate plate 22. Therefore, in the head substrate 12, the region that covers the common circulation channel 22b from the wiring substrate 51 side is more likely to bend than the region outside the common circulation channel 22b when an external force in the thickness direction is applied. Therefore, in the head substrate 12, the region that covers the common circulation flow path 22b from the wiring substrate 51 side is referred to as a flexible region 21d having flexibility.

  In addition, in the present embodiment, the mode in which the common circulation channel is formed in the body plate and the intermediate plate is shown, but it is sufficient if it is formed in the substrate that constitutes the head substrate, and the present invention is not limited to this. Needless to say. For example, in addition to the body plate and the intermediate plate, a separate substrate may be provided and the common circulation channel may be formed in the substrate.

"Piezoelectric element"
The piezoelectric element 13 has a lower electrode 31, a piezoelectric body 32, and an upper electrode 33. The piezoelectric element 13 may further have an orientation control layer (seed layer, buffer layer) for controlling the crystal orientation of the piezoelectric body 32 between the lower electrode 31 and the piezoelectric body 32.

  The lower electrode 31 is a common electrode provided commonly to the plurality of pressure chambers 21 a, and is formed over substantially the entire surface of the head substrate 12. The lower electrode 31 is configured by laminating a Ti (titanium) layer and a Pt (platinum) layer. The Ti layer is formed to improve the adhesion between the Pt layer and the lower layer (thermal oxide film or diaphragm 21c). The Ti layer has a thickness of, for example, about 0.02 μm, and the Pt layer has a thickness of, for example, about 0.1 μm.

  The piezoelectric body 32 is composed of, for example, a ferroelectric thin film such as lead zirconate titanate (PZT) (in particular, a film made of an oxide having a perovskite structure), and is supported by the head substrate 12 together with the lower electrode 31. A pressure is applied to the ink in the pressure chamber 21a. The piezoelectric body 32 is located above the pressure chamber 21a (on the side of the wiring board 51), and is provided corresponding to each pressure chamber 21a. The piezoelectric body 32 is formed of, for example, a piezoelectric thin film having a thickness of 1 μm or more and 10 μm or less, but may be formed of a thicker film (eg, bulk). The piezoelectric body 32 may be made of PZT to which an additive such as lanthanum (La) or niobium (Nb) is added, and a lead-free piezoelectric material such as potassium sodium niobate (KNN). May be composed of

  The upper electrode 33 is an individual electrode for driving the piezoelectric body 32, and is provided corresponding to each piezoelectric body 32 such that the piezoelectric body 32 is sandwiched between the upper electrode 33 and the lower electrode 31 in the film thickness direction. . The upper electrode 33 is formed by stacking a Ti layer and a Pt layer. The Ti layer is formed to improve the adhesion between the piezoelectric body 32 and the Pt layer. The Ti layer has a thickness of, for example, about 0.02 μm, and the Pt layer has a thickness of, for example, about 0.1 to 0.2 μm. A layer made of gold (Au) may be formed instead of the Pt layer.

  A part of the piezoelectric element 13 is covered with the insulating film 34. The upper electrode 33 corresponding to each piezoelectric body 32 is electrically connected to the wiring 35 (first wiring) provided along the surface of the insulating film 34. Therefore, in the inkjet substrate 11, a plurality of wirings 35 are provided by the number corresponding to the number of the piezoelectric bodies 32 (pressure chambers 21a). Each wiring 35 is formed on the insulating film 34 so as to straddle the common circulation flow path 22b, and at a position overlapping at least a part of the common circulation flow path 22b, the connection terminal 35a (first connection terminal). ) Respectively. The connection terminal 35a is electrically connected to a connection terminal 53a of the wiring board 51, which will be described later, via an adhesive member 61. The material of the wiring 35 may be the same metal material as the upper electrode 33, or may be a different material. A part of the wiring 35 is covered with an insulating film 36. Note that the insulating film 36 may not be provided.

(Wiring board)
The wiring substrate 51 is a substrate that supplies the drive signal to the inkjet substrate 11, and is configured by, for example, a flexible substrate called FPC (Flexible Printed Circuits). In this wiring board 51, a plurality of wirings 53 (second wirings) made of a conductive metal such as copper foil are attached to an insulating base film 52 made of polyimide or the like, and a part of the wirings 53 is insulated. It is formed by covering with a film 54. Each wiring 53 is electrically connected to a drive circuit (not shown) that generates the drive signal in order to supply the drive signal to the piezoelectric element 13.

The plurality of wirings 53 includes a wiring 53a and a wiring 53b. The wiring 53a is a wiring that is electrically connected to the wiring 35 of the inkjet substrate 11 and supplies the drive signal to the upper electrode 33 of the piezoelectric element 13 via the wiring 35. The wiring 53a has a connection terminal 53a ₁ (second connection terminal) electrically connected to the connection terminal 35a of the wiring 35 at a position overlapping at least a part of the common circulation flow path 22b. . The wiring 53b is a wiring that is electrically connected to the lower electrode 31 of the inkjet substrate 11 and applies a potential (for example, ground potential 0V) to the lower electrode 31.

(Adhesive member)
The adhesive member 61 is an adhesive for adhering the inkjet substrate 11 and the wiring substrate 51, and is, for example, an anisotropic conductive adhesive 62 in which conductive particles 62a made of metal are mixed in a thermosetting resin 62b. Composed. As the anisotropic conductive adhesive 62, an anisotropic conductive film (ACF; Anisotropic Conductive Film) or an anisotropic conductive paste (ACP; Anisotropic Conductive Paste) can be used.

Here, on the inkjet substrate 11, a region that overlaps at least a part of the common circulation flow channel 22b is referred to as a first region R1 and overlaps with the outside of the common circulation flow channel 22b (a portion having a constant thickness). The area to be wrapped is referred to as a second area R2 (see FIG. 2). The adhesive member 61 has a structure in which the wiring 35 (connection terminal 35a) of the inkjet substrate 11 and the wiring 53a (connection terminal 53a ₁ ) of the wiring substrate 51 are electrically connected at least in the first region R1. The inkjet substrate 11 and the wiring substrate 51 are bonded to each other in both the first region R1 and the second region R2.

  When the adhesive member 61 is made of an anisotropic conductive adhesive, the adhesive member 61 is located not only in the first region R1 but also in the second region R2. Will be electrically connected via the adhesive member 61 in both the first region R1 and the second region R2. However, in the second region R2, the ink jet substrate 11 and the wiring substrate 51 may be mechanically bonded to each other by the adhesive member 61 at a minimum, and the wiring 35 and the wiring 53a may not be electrically connected. Good. The details of this point will be described later.

  Further, the adhesive member 61 has the first region R1 and the second region R1 so that the lower electrode 31 of the inkjet substrate 11 and the wiring 53b of the wiring substrate 51 are electrically connected at least in the first region R1. The inkjet substrate 11 and the wiring substrate 51 are bonded to each other in both of the regions R2. When the adhesive member 61 is made of an anisotropic conductive adhesive, the lower electrode 31 and the wiring 53b are electrically connected via the adhesive member 61 in both the first region R1 and the second region R2. Will be done.

  Further, in the present embodiment, the adhesive member 61 is located on the inkjet substrate 11 in the first region R1 and the second regions R2 on both sides of the first region R1. That is, in the second region R2 on the inkjet substrate 11, a region located on the piezoelectric body 32 side with respect to the first region R1 is referred to as a region R2a, and a region located on the opposite side to the piezoelectric body 32 is defined as When the region R2b is used, the adhesive member 61 is located in both the region R2a and the region R2b.

  In the above configuration, the drive signal from the drive circuit is supplied to the upper electrode 33 via the wiring 53a of the wiring substrate 51, the adhesive member 61 and the wiring 35 of the inkjet substrate 11, and also via the wiring 53b and the adhesive member 61. Is supplied to the lower electrode 31. As a result, a potential difference is generated between the lower electrode 31 and the upper electrode 33, and the piezoelectric body 32 expands and contracts in the direction perpendicular to the thickness direction according to the potential difference. Then, due to the difference in length between the piezoelectric body 32 and the vibration plate 21c, a curvature is generated in the vibration plate 21c, and the vibration plate 21c is displaced (curved or vibrated) in the thickness direction.

  Therefore, if the ink is stored in the pressure chamber 21a, the pressure wave is propagated to the ink in the pressure chamber 21a by the vibration of the diaphragm 21c described above. As a result, the ink in the pressure chamber 21a is ejected to the outside as an ink droplet via the communication passage 22a and the nozzle 23a.

[Method for manufacturing inkjet head]
Next, a method for manufacturing the above-described inkjet head 2 will be described. 4 and 5 are cross-sectional views schematically showing the manufacturing process of the inkjet substrate 11 of the inkjet head 2. First, the body plate 21, the intermediate plate 22, and the nozzle plate 23 are manufactured by using a known semiconductor process or the like. At this time, as shown in FIG. 4, the pressure chamber 21a, the piezoelectric element 13, the wiring 35, the insulating film 36, and the like are patterned and formed on the body plate 21, and the common circulation channel 22b and the like are formed on the intermediate plate 22. Patterned and formed. Further, as shown in FIG. 5, nozzles 23a and the like are patterned and formed on the nozzle plate 23. The details of the manufacturing method of the body plate 21 on which the piezoelectric element 13 and the like are formed (hereinafter referred to as the body plate 21 with a piezoelectric element) will be described later.

  Next, as shown in FIG. 4, the body plate 21 with the piezoelectric element and the intermediate plate 22 are aligned (positional adjustment) at a predetermined position and bonded by an adhesive. Subsequently, as shown in FIG. 5, the intermediate plate 22 to which the body plate 21 is joined and the nozzle plate 23 are aligned at a predetermined position and joined by an adhesive. Thereby, the inkjet substrate 11 is obtained. The body plate 21 and the intermediate plate 22, and the intermediate plate 22 and the nozzle plate 23 may be joined by anodic bonding. FIG. 6 shows a plan view of the obtained inkjet substrate 11. The sectional view of the inkjet substrate 11 of FIG. 5 corresponds to the sectional view taken along the line B-B ′ of FIG. 6. Further, in FIG. 6, for convenience, the lower electrode 31 of the piezoelectric element 13 is not shown (this way of illustration is the same in the following plan views).

  Next, as shown in FIGS. 7A and 7B, on the inkjet substrate 11, the first region R1 that overlaps at least a part of the common circulation flow channel 22b and the outside of the common circulation flow channel 22b overlaps. The adhesive member 61 is arranged in the second region R2 (regions R2a and R2b) (first step). Then, the adhesive member 61 is temporarily pressure-bonded and attached in the first region R1 and the second region R2. Particularly, in the first region R1, the adhesive member 61 is aligned and attached so as to cover the connection terminals 35a of the plurality of wirings 35 formed on the body plate 21.

  At this time, as the above-mentioned adhesive member 61, ACF which is the anisotropic conductive adhesive 62 containing the conductive particles 62a was used, and this was arranged in both the first region R1 and the second region R2. 7A shows a cross-sectional view of the inkjet substrate 11 on which the adhesive member 61 is arranged, and FIG. 7B shows a plan view of the inkjet substrate 11, but the cross-sectional view of FIG. 7A is C- in FIG. 7B. It corresponds to a cross-sectional view taken along the line C ′. Further, in FIG. 7B, for the purpose of clarifying the adhesive member 61, the adhesive member 61 is hatched for convenience.

Then, as shown in FIGS. 8 and 9, the ink jet substrate 11 is so arranged that the wiring 35 (connection terminal 35a) of the ink jet substrate 11 and the wiring 53 (connection terminal 53a ₁ ) of the wiring substrate 51 overlap each other. The wiring board 51 is aligned with the wiring board 51. Since the lower electrode 31 is formed on the entire surface of the inkjet substrate 11, the wiring 53b of the wiring substrate 51 inevitably overlaps the lower electrode 31 during the above alignment of the wiring substrate 51. 8 shows a cross-sectional view of the wiring substrate 51 and the inkjet substrate 11 after alignment, and FIG. 9 shows a plan view of the wiring substrate 51 and the inkjet substrate 11, but the cross-sectional view of FIG. 9 corresponds to a sectional view taken along the line DD ′ in FIG.

Then, as shown in FIG. 10, the tool 71 is pressed against the wiring board 51 to heat and pressurize the wiring board 51 to the inkjet board 11. More specifically, by pressing the wiring substrate 51 against the inkjet substrate 11, the wiring 35 (connection terminal 35a) of the inkjet substrate 11 and the wiring 53a (connection terminal 53a ₁ ) of the wiring substrate 51 are bonded via the adhesive member 61. And electrically connect with each other, and the ink jet substrate 11 and the wiring substrate 51 are bonded by the adhesive member 61 located in the first region R1 and the second region R2 (second step). Further, in this step, the lower electrode 31 and the wiring 53 b of the wiring board 51 are electrically connected via the adhesive member 61 by the pressing of the wiring board 51.

  Since the adhesive member 61 is located in both the first region R1 and the second region R2 on the inkjet substrate 11, the wiring 35 and the wiring 53a are the first region R1 and the second region R2. Both R2 are electrically connected via the adhesive member 61. Similarly, the lower electrode 31 and the wiring 53b are electrically connected via the adhesive member 61 in both the first region R1 and the second region R2.

  Although the tool 71 is pressed against the wiring board 51 and the wiring board 51 is pressed against the inkjet board 51 here, the inkjet board 11 is heated with the tool 71 and the like. You may press to the side. That is, one of the inkjet substrate 11 and the wiring substrate 51 may be pressed relative to the other to apply pressure.

By the above-mentioned pressurization, the conductive particles 62a contained in the adhesive member 61 (ACF) are trapped between the connection terminal 35a and the connection terminal 53a ₁ so that conduction can be established. Similarly, the conductive particles 62a are trapped between the lower electrode 31 and the wiring 53b, so that conduction can be established. Further, the resin 62b contained in the ACF protrudes by pressurization and is further heated to cure. As a result, the inkjet head 2 shown in FIGS. 2 and 3 is completed. The heating temperature and the pressure at the time of pressurization in the second step differ depending on the adhesive member 61 used, but when an anisotropic conductive adhesive 62 made of ACF is used as the adhesive member 61, the heating temperature is, for example, 150 to The temperature is 250 ° C. and the pressure is, for example, about 3 to 20 MPa.

[Summary]
As described above, the inkjet head 2 of the present embodiment has a configuration in which the inkjet substrate 11 and the wiring substrate 51 are bonded by the adhesive member 61. The adhesive member 61 is located in both the first region R1 and the second region R2 so that the wiring 35 and the wiring 53a are electrically connected to each other in at least the first region R1, and the inkjet substrate. 11 and the wiring board 51 are bonded. Further, the method for manufacturing the inkjet head 2 of the present embodiment includes a bonding step of bonding the inkjet substrate 11 and the wiring board 51 with the bonding member 61, and the bonding step includes forming the first region R1 on the inkjet substrate 11. The first step of arranging the adhesive member 61 in the second region R2, and by pressing the wiring substrate 51 relative to the inkjet substrate 11 via the adhesive member 61, at least the wiring 35 and the wiring 53a are formed. A second step of electrically connecting the first substrate R1 and the wiring substrate 51 with each other with an adhesive member 61 located in the first region R1 and the second region R2. is doing.

  Since the wiring 35 of the inkjet substrate 11 and the wiring 53a of the wiring substrate 51 are electrically connected by the adhesive member 61 in the first region R1 overlapping at least a part of the common circulation flow channel 22b, In the region R1 of 1, it is possible to secure a bonding area required for electrical connection of both wirings. For example, the width of the contact region between the wiring 35 and the wiring 53a (the length in the left-right direction in FIG. 2) required to secure the above-mentioned bonding area is equal to the width of the common circulation channel 22b (for example, 1.5 mm). On the other hand, it is about 1 mm. By electrically connecting both wirings in the first region R1 as described above, the second region R2 overlapping with the outside of the common circulation channel 22b is necessary for electrically connecting both wirings. It is not necessary to widen it to secure a large adhesive area. Therefore, even with the configuration in which the common circulation flow path 22b is provided in the inkjet substrate 11, it is possible to prevent the inkjet substrate 11 and hence the inkjet head 2 from becoming large.

  In addition, the adhesive member 61 is located on both the first region R1 and the second region R2 on the inkjet substrate 11, and adheres the inkjet substrate 11 and the wiring substrate 51. In such a configuration, the adhesive member 61 is arranged on both the first region R1 and the second region R2 on the inkjet substrate 11, and the wiring substrate 51 is relatively pressed against the inkjet substrate 11 to bond the two. It can be realized by the above-mentioned first and second steps. The stress at the time of pressing the wiring substrate 51 is distributed to the adhesive member 61 located in the first region R1 and the adhesive member 61 located in the second region R2, so that the flexible region 21d (of the head substrate 12 ( It is possible to reduce the possibility that the upper wall of the common circulation channel 22b will be cracked due to stress concentration. As a result, the reliability of the inkjet head 2 can be ensured.

  That is, according to the configuration of the inkjet head 2 of the present embodiment and the manufacturing method thereof, even when the common circulation channel 22b is provided on the inkjet substrate 11, the inkjet head 2 is upsized while ensuring the reliability of the inkjet head 2. Can be avoided.

  The adhesive member 61 is located on the inkjet substrate 11 in the first region R1 and the second regions R2 (regions R2a and R2b) on both sides of the first region R1. In addition, in the first step of the manufacturing method, the adhesive member 61 is provided on the inkjet substrate 11 in the first region R1 and the second regions R2 (regions R2a and R2b) on both sides of the first region R1. It is arranged. In this case, it is considered that the stress at the time of pressing the wiring board 51 is distributed in a well-balanced manner to the adhesive members 61 located in the first region R1 and the adhesive members 61 located in the regions R2a and R2b on both sides of the adhesive member 61. . As a result, the effect of reducing cracks in the flexible region 21d due to stress concentration can be enhanced, and the reliability of the inkjet head 2 can be improved.

  Further, the adhesive member 61 includes an anisotropic conductive adhesive 62 having conductive particles 62a, and the anisotropic conductive adhesive 62 is located on the inkjet substrate 11 in the first region R1. Further, in the above-described manufacturing method, in the first step, the anisotropic conductive adhesive 62 as the adhesive member 61 is arranged on the inkjet substrate 11 in the first region R1.

  Since the anisotropic conductive adhesive 62 is located in the first region R1, the inkjet substrate 11 and the wiring substrate 51 are mechanically bonded in the first region R1 and the same first region R1 is used. In, the wiring 35 and the wiring 53a can be electrically connected to each other through the conductive particles 62a. That is, by using the anisotropic conductive adhesive 62, electrical connection between the wiring 35 and the wiring 53a in the first region R1 and mechanical bonding between the inkjet substrate 11 and the wiring substrate 51 are simultaneously performed. Can be realized.

  Further, the anisotropic conductive adhesive 62 as the adhesive member 61 is located on the inkjet substrate 11 in the second region R2 in addition to the first region R1. Further, in the above manufacturing method, in the first step, the anisotropic conductive adhesive 62 is arranged in the second region R2 in addition to the first region R1. In this way, the same anisotropic conductive adhesive 62 as the adhesive located in the first region R1 is used to bond the inkjet substrate 11 and the wiring substrate 51 in the second region R2. It is not necessary to prepare a plurality of types, and it is not necessary to use a plurality of types of adhesive members 61 according to the adhesion position. Therefore, the manufacturing of the inkjet head 2 is easier than in the case where a plurality of types of adhesive members 61 are prepared and bonded.

  The anisotropic conductive adhesive 62 is ACF (anisotropic conductive film) or ACP (anisotropic conductive paste). By using ACF or ACP, electrical connection between the wiring 35 and the wiring 53a can be realized easily and reliably.

  Further, in the present embodiment, the head substrate 12 of the inkjet substrate 11 has a plurality of pressure chambers 21a, and the common circulation flow path 22b communicates with each pressure chamber 21a to circulate the non-ejection ink in common. It is a flow path. As described above, when the common circulation flow path 22b is a common flow path common to the individual pressure chambers 21a, if the number of the pressure chambers 21a is increased in order to achieve high definition by high-density arrangement of the nozzles 23a, the common circulation flow path 22b is increased. The flow path 22b is likely to be upsized, and the inkjet head 2 is likely to be upsized. Therefore, the wiring 35 and the wiring 53a are electrically connected to each other in the first region R1 that overlaps at least a part of the common circulation flow path 22b, and the inkjet substrate 11 and thus the inkjet head 2 can be prevented from becoming large. The configuration of the present embodiment that achieves the above is very effective when the common circulation flow path 22b is a common flow path common to the pressure chambers 21a.

Further, the wiring 35 of the inkjet substrate 11 includes a connection terminal 35a (first connection terminal) located at a position overlapping at least a part of the common circulation flow path 22b, and the wiring 53 of the wiring substrate 51 includes the common circulation flow. It includes a connection terminal 53a ₁ in at least a portion overlapping with the position of the road 22b (second connection terminal), and the connecting terminals 35a and connection terminal 53a ₁ is electrically connected. Further, in the second step of the above-described manufacturing method, the wiring board 51 is relatively pressed against the inkjet substrate 11 so that the connection terminal 35a included in the wiring 35 and the connection terminal 53a ₁ included in the wiring 53a are connected. , Is electrically connected at a position overlapping at least a part of the common circulation flow path 22b.

Since the connection terminal 35a and the connection terminal 53a ₁ are connected at a position (first region R1) overlapping at least a part of the common circulation channel 22b, the connection terminal 35a is connected to the outside of the common circulation channel 22b. It is not necessary to secure a wide space for connecting the terminal 53a ₁ with a constant contact area. This makes it possible to avoid the inkjet substrate 11 and thus the inkjet head 2 from becoming large.

  The inkjet printer 1 of the present embodiment includes the inkjet head 2 described above, and ejects ink from the inkjet head 2 toward the recording medium. According to the configuration of the inkjet head 2 described above, even when the common circulation flow path 22b is provided in the inkjet substrate 11, the reliability of the inkjet head 2 can be ensured and the inkjet head 2 can be prevented from being upsized, so that reliability and It is possible to realize the inkjet printer 1 that is advantageous in terms of downsizing.

[Other configuration of inkjet head]
FIG. 11 is a cross-sectional view showing another configuration of the inkjet head 2. The adhesive member 61 has a first region R1 and one region (one of the regions R2a and R2b) of the second regions R2 located on both sides of the first region R1 on the inkjet substrate 11. May be located at. In such a configuration, in the first step of the manufacturing method described above, the adhesive member 61 is arranged in the first region R1 and the second region R2 on one side on the inkjet substrate 11, and the second step is performed. It can be realized by pressing the wiring substrate 51 with and adhering it to the inkjet substrate 11 via the adhesive member 61.

  Even with such a configuration, the stress at the time of pressing the wiring substrate 51 in the second step is caused by the adhesive member 61 located in the first region R1 and the second region R2 on one side (for example, the region R2a). It is considered that since the stress is concentrated on the flexible region 21d because it is dispersed in the adhesive member 61 located at, the cracks in the flexible region 21d can be reduced. Thereby, the effect of improving the reliability of the inkjet head 2 can be expected.

  12 and 13 are cross-sectional views showing still another configuration of the inkjet head 2. The adhesive member 61 (anisotropic conductive adhesive 62) may be continuously located on the inkjet substrate 11 from the first region R1 to the second region R2. At this time, as shown in FIG. 12, the anisotropic conductive adhesive 62 is formed so as to have a width larger than the width of the common circulation channel 22b, and the second region R2 on both sides of the first region R1. (Region R2a / R2b) may be continuously located, or as shown in FIG. 13, it may be continuously located from the first region R1 to the second region R2 on one side (for example, region R2a). May be. In such a configuration, in the first step of the manufacturing method described above, the anisotropic conductive adhesive 62 is arranged on the inkjet substrate 11 so as to be continuous from the first region R1 to the second region R2. It can be realized by pressing the wiring substrate 51 in the second step and adhering it to the inkjet substrate 11 via the adhesive member 61.

  In this case, since it is not necessary to dispose the anisotropic conductive adhesive 62 separately in the first region R1 and the second region R2, the anisotropic conductive adhesive 62 can be easily arranged. Therefore, as the anisotropic conductive adhesive 62, one film-like adhesive (for example, ACF) extending from the first region R1 to the second region R2 is used, or the first region R1 to the second region R2. By continuously applying the paste adhesive (for example, ACP) to R2, it becomes easy to bond the inkjet substrate 11 and the wiring substrate 51.

  FIG. 14 is a cross-sectional view showing still another configuration of the inkjet head 2. The adhesive member 61 of the inkjet head 2 may further include a non-conductive adhesive 63 in addition to the anisotropic conductive adhesive 62 described above. The inkjet head 2 may have a configuration in which the anisotropic conductive adhesive 62 is located in the first region R1 and the non-conductive adhesive 63 is located in the second region R2. In such a configuration, in the first step of the manufacturing method described above, the anisotropic conductive adhesive 62 is arranged in the first region R1, while the non-conductive adhesive 63 is arranged in the second region R2. It can be realized by pressing the wiring substrate 51 in the second step and adhering it to the inkjet substrate 11 via the adhesive member 61.

  As the non-conductive adhesive 63, for example, a non-conductive film (NCF; Non Conductive Film) or a non-conductive paste (NCP; Non Conductive Paste) can be used. The non-conductive adhesive 63 may be arranged in the second regions R2 (regions R2a and R2b) on both sides of the first region R1 as shown in FIG. May be arranged only in the second region R2 (for example, the region R2a).

  Since the anisotropic conductive adhesive 62 is located in the first region R1, the electrical connection (conduction) between the wiring 35 and the wiring 53a is secured in the first region, so that the second region R2 is formed. Then, the electrical connection between the wiring 35 and the wiring 53a is unnecessary. Therefore, it is possible to increase the mechanical adhesive strength by disposing the non-conductive adhesive 63 in the second region R2 and performing the adhesion.

  In particular, by using NCF or NCP as the non-conductive adhesive 63, it becomes possible to easily realize the bonding using the non-conductive adhesive 63.

  15A is a plan view showing still another configuration of the inkjet head 2, FIG. 15B is a sectional view taken along the line EE ′ in FIG. 15A, and FIG. 15C is a line FF ′ in FIG. 15A. FIG. In addition, FIG. 16 is a part of a cross-sectional view taken along the line G-G ′ in FIG. 15A. The inkjet head 2 is different from that shown in FIG. 2 and the like in that the formation of the insulating film 36 covering the upper electrode 33 and the like is omitted.

  The adhesive member 61 may be composed of only the non-conductive adhesive 63. In this case, the wiring 35 and the wiring 53a of the inkjet substrate 11 are in direct contact with each other at least in the first region R1 (see FIGS. 15B and 16). Then, the non-conductive adhesive 63 is located around the wiring 35 and the wiring 53a that are in direct contact with each other in the first region R1, and bonds the inkjet substrate 11 and the wiring substrate 51 to each other ( (See FIGS. 15C and 16). With such a configuration, in the first step of the manufacturing method described above, the non-conductive adhesive 63 is arranged in the first region R1, and in the second step, the wiring substrate 51 is relatively attached to the inkjet substrate 11. The wiring 35 and the wiring 53a are brought into direct contact with each other in at least the first region R1 by pressing to, and the non-conductivity located around the wiring 35 and the wiring 53a in direct contact with each other in the first region R1. It can be realized by bonding the inkjet substrate 11 and the wiring substrate 51 with the adhesive 63.

  Since the wiring 35 and the wiring 53a are in direct contact with each other in the first region R1, their electrical connection is secured. Further, since the non-conductive adhesive 63 is located around the wiring 35 and the wiring 53a that are in direct contact with each other in the first region R1 and adheres the inkjet substrate 11 and the wiring substrate 51, The inkjet substrate 11 and the wiring substrate 51 can be mechanically adhered to each other without disturbing the electrical connection.

  Further, as shown in FIG. 15C, the non-conductive adhesive 63 is located in the second region R2 in addition to the first region R1. With such a configuration, in the first step of the above-described manufacturing method, the non-conductive adhesive 63 is further arranged in the second region R2 in addition to the first region R1, and the inkjet process is performed in the second step. It can be realized by relatively pressing the wiring substrate 51 against the substrate 11 and adhering both by the non-conductive adhesive 63.

  The stress at the time of pressing the wiring board 51 is the adhesive member 61 (non-conductive adhesive 63) located in the first region R1 and the adhesive member 61 (non-conductive adhesive 63) located in the second region R2. Therefore, it is possible to reduce the possibility that the flexible region 21d of the head substrate 12 is cracked due to stress concentration, and to secure the reliability of the inkjet head 2.

  In addition, the same non-conductive adhesive 63 as the adhesive located in the first region R1 is used to bond the inkjet substrate 11 and the wiring substrate 51 in the second region R2. Therefore, a plurality of types of adhesive members 61 are prepared. It is not necessary to use different types of adhesive members 61 depending on the adhesion position. Therefore, the manufacturing of the inkjet head 2 is easier than in the case where a plurality of types of adhesive members 61 are prepared and bonded.

  Further, as shown in FIG. 15C, the non-conductive adhesive 63 is continuously positioned on the inkjet substrate 11 from the first region R1 to the second region R2. In such a configuration, in the first step of the manufacturing method described above, the non-conductive adhesive 63 is arranged on the inkjet substrate 11 so as to be continuous from the first region R1 to the second region R2, In the second step, it can be realized by pressing the wiring substrate 51 and adhering it to the inkjet substrate 11 via the non-conductive adhesive 63.

  In this case, since it is not necessary to separately dispose the non-conductive adhesive 63 in the first region R1 and the second region R2, the disposition of the non-conductive adhesive 63 becomes easy. Therefore, as the non-conductive adhesive 63, one sheet of film adhesive (for example, NCF) extending from the first region R1 to the second region R2 is used, or the first region R1 to the second region R2 are used. By continuously applying the paste-like adhesive (for example, NCP) over this period, it becomes easy to bond the inkjet substrate 11 and the wiring substrate 51.

[Other]
17 and 18 are cross-sectional views showing still another configuration of the inkjet head 2. As shown in FIG. 17, the non-conductive adhesive 63 as the adhesive member 61 is continuously located on the inkjet substrate 11 from the first region R1 to the second region R2 on one side (for example, R2a). Good. Further, as shown in FIG. 18, the non-conductive adhesive 63 as the adhesive member 61 is discontinuous in the first region R1 and the second region R2 (for example, R2a) on the inkjet substrate 11 ( They may be located (separated from each other).

  19 is a plan view showing another configuration of the inkjet substrate 11 of the inkjet head 2, FIG. 20 is a perspective view including an HH ′ cross section of the inkjet substrate 11 of FIG. 19, and FIG. FIG. 21 is an enlarged sectional view showing a J portion of FIG. 20. Note that the lower electrode 31 is not shown in FIG. 19 for convenience.

  The plurality of pressure chambers 21a of the inkjet substrate 11 are arranged side by side along the longitudinal direction of the common circulation flow path 22b on both sides in the width direction of the common circulation flow path 22b, and are arranged in a staggered shape in plan view as a whole. May be. In this configuration, each pressure chamber 21a communicates with the common circulation passage 22b from opposite sides in the width direction of the common circulation passage 22b. Further, each pressure chamber 21a communicates with each ink supply port 21b within the body plate 21. The piezoelectric body 32 and the upper electrode 33 are arranged in a zigzag pattern corresponding to each pressure chamber 21a. The wiring 35 electrically connected to the upper electrode 33 is electrically connected to the upper electrode 33 through an opening 34a provided in the insulating film 34 that covers a part of the upper electrode 33, It extends from the connection position with the upper electrode 33 so as to straddle the common circulation channel 22b. Even when the inkjet substrate 11 having such a configuration is used, the same effect as that of this embodiment can be obtained by configuring the inkjet head 2 by adopting the same bonding method as that of this embodiment described above.

  In the above description, the inkjet head and the inkjet printer that eject the ink for image formation have been described as an example, but the ejected ink is not limited to the ink for image formation. For example, a liquid such as a color material used for manufacturing a color filter for a liquid crystal display or an electrode material used for forming an electrode for an organic EL display or an FED (field emission display) may be used as the ink.

[About manufacturing method of body plate with piezoelectric element]
Next, details of the above-described manufacturing method of the body plate 21 with a piezoelectric element will be described. FIG. 22 is a cross-sectional view showing details of the manufacturing process of the body plate 21 with a piezoelectric element.

  First, the body plate 21 is prepared. As the body plate 21, crystalline silicon (Si) which is widely used in MEMS (Micro Electro Mechanical Systems) can be used. Here, two Si substrates 81 and 82 are bonded via an oxide film 83. The SOI structure is used.

The body plate 21 is placed in a heating furnace and held at about 1500 ° C. for a predetermined time to form a thermal oxide film 21e made of SiO _{2 on} the surface of one Si substrate 82 (corresponding to the vibrating plate 21c), and the other. A thermal oxide film 21f is formed on the surface of the Si substrate 81.

  Next, each layer of Ti and Pt is sequentially formed on the thermal oxide film 21e by the sputtering method to form the lower electrode 31. Although the lower electrode 31 is not patterned here, the lower electrode 31 may be patterned into a desired shape. Then, the body plate 21 is reheated to about 600 ° C., and the PZT layer 32a is formed by the sputtering method.

  Next, a photosensitive resin 91 is applied onto the PZT layer 32a by a spin coating method, and an unnecessary portion of the photosensitive resin 91 is removed by exposing and etching through a mask to form a piezoelectric body 32 to be formed. Transfer the shape. After that, using the photosensitive resin 91 as a mask, the shape of the layer 32 a is processed by the reactive ion etching method to form the piezoelectric body 32.

  Next, each layer of Ti and Pt is sequentially formed on the lower electrode 31 so as to cover the piezoelectric body 32 by a sputtering method to form a layer 33a. Subsequently, a photosensitive resin 92 is applied onto the layer 33a by a spin coating method, and an unnecessary portion of the photosensitive resin 92 is removed by exposing and etching through a mask to transfer the shape of the upper electrode 33 to be formed. To do. Then, using the photosensitive resin 92 as a mask, the shape of the layer 33a is processed by the reactive ion etching method to form the upper electrode 33. As a result, the piezoelectric element 13 including the lower electrode 31, the piezoelectric body 32, and the upper electrode 33 is formed.

Next, an insulating film 34 made of SiO ₂ is formed on the lower electrode 31 so as to cover a part of the upper electrode 33 by, for example, a sputtering method. Then, an opening 34a is formed above the upper electrode 33 in the insulating film 34 by etching or the like. Then, a wiring 35 made of a Pt layer is formed on the insulating film 34 by, for example, a sputtering method so as to be electrically connected to the upper electrode 33 through the opening 34a. After that, an insulating film 36 made of SiO ₂ is formed so as to cover the wiring 35 by, for example, a sputtering method.

  After that, a photosensitive resin is applied to the back surface of the body plate 21 (on the side of the thermal oxide film 21f) by a spin coating method, and exposed and etched through a mask to remove unnecessary portions of the photosensitive resin, The shape of the pressure chamber 21a or the like to be formed is transferred. Then, the body plate 21 is removed by the reactive ion etching method using the photosensitive resin as a mask to form the pressure chamber 21a and the like, and then the thermal oxide film 21f is removed. As a result, the body plate 21 with a piezoelectric element shown in FIG. 4 is completed. By removing the portion of the body plate 21 corresponding to the pressure chamber 21a, the diaphragm 21d serving as the upper wall of the pressure chamber 21a is formed.

  The inkjet head of the present invention can be used in an inkjet printer.

1 Inkjet Printer 2 Inkjet Head 11 Inkjet Substrate 12 Head Substrate 21a Pressure Chamber 21d Flexible Region 22b Common Circulation Channel (Circulation Channel, Common Channel)
23a Nozzle 32 Piezoelectric body 33 Upper electrode (individual electrode)
35 wiring (first wiring)
35a connection terminal (first connection terminal)
51 wiring board 53a wiring (second wiring)
53a ₁ connection terminal (second connection terminal)
61 Adhesive Member 62 Anisotropic Conductive Adhesive 62a Conductive Particle 63 Non-Conductive Adhesive R1 First Region R2 Second Region R2a Region (Second Region)
R2b area (second area)

Claims (29)

An inkjet head including an inkjet substrate that ejects ink based on a drive signal, a wiring substrate that supplies the drive signal to the inkjet substrate, and an adhesive member for adhering the inkjet substrate and the wiring substrate to each other. There
The inkjet substrate is
A pressure chamber containing ink, a nozzle communicating with the pressure chamber, a circulation channel for circulating non-ejection ink other than the ink ejected from the nozzle, and the circulation channel from the wiring board side A head substrate having a flexible region;
A piezoelectric body that is supported by the head substrate and applies a pressure to the ink in the pressure chamber;
Individual electrodes for driving the piezoelectric body,
A first wiring electrically connected to the individual electrode,
The wiring board includes a second wiring for supplying the drive signal to the individual electrode,
On the inkjet substrate, a region overlapping with at least a part of the circulation flow channel is a first region, and a region overlapping with the outside of the circulation flow channel is a second region,
The adhesive member is located in both the first region and the second region so that the first wiring and the second wiring are electrically connected at least in the first region. And an ink jet head characterized in that the ink jet substrate and the wiring substrate are adhered to each other. The piezoelectric body is supported by the head substrate and is located above the pressure chamber,
In the head substrate, the circulation channel is in communication with the pressure chamber via an individual channel,
The adhesive member includes, on the inkjet substrate, one of the first region and the second region, which is located on the piezoelectric body side with respect to the first region and on the opposite side of the piezoelectric body. The inkjet head according to claim 1, wherein the inkjet head is located in both of the areas where it is located. The piezoelectric body is supported by the head substrate and is located above the pressure chamber,
In the head substrate, the circulation channel is in communication with the pressure chamber via an individual channel,
The adhesive member includes, on the inkjet substrate, one of the first region and the second region, which is located on the piezoelectric body side with respect to the first region and on the opposite side of the piezoelectric body. The inkjet head according to claim 1, wherein the inkjet head is located in either one of the areas . The adhesive member includes an anisotropic conductive adhesive having conductive particles,
The inkjet head according to any one of claims 1 to 3, wherein the anisotropic conductive adhesive is located in the first region.   The inkjet head according to claim 4, wherein the anisotropic conductive adhesive is further located in the second region.   The inkjet head according to claim 5, wherein the anisotropic conductive adhesive is continuously located on the inkjet substrate from the first region to the second region.   The inkjet head according to any one of claims 4 to 6, wherein the anisotropic conductive adhesive is an anisotropic conductive film or an anisotropic conductive paste. The adhesive member includes a non-conductive adhesive,
The inkjet head according to claim 4, wherein the non-conductive adhesive is located in the second region. The adhesive member includes a non-conductive adhesive,
The first wiring and the second wiring are in direct contact with each other at least in the first region,
The non-conductive adhesive is located around the first wiring and the second wiring that are in direct contact with each other in the first region, and bonds the inkjet substrate and the wiring substrate to each other. The inkjet head according to any one of claims 1 to 3, wherein   The inkjet head according to claim 9, wherein the non-conductive adhesive is further located in the second region.   The inkjet head according to claim 10, wherein the non-conductive adhesive is continuously located on the inkjet substrate from the first region to the second region.   The inkjet head according to claim 8, wherein the non-conductive adhesive is a non-conductive film or a non-conductive paste. The head substrate has a plurality of the pressure chambers,
13. The inkjet head according to claim 1, wherein the circulation flow path is a common flow path that communicates with each of the pressure chambers and circulates the non-ejection ink. The first wiring includes a first connection terminal located at a position overlapping at least a part of the circulation flow path,
The second wiring includes a second connection terminal located at a position overlapping at least a part of the circulation flow path,
The inkjet head according to any one of claims 1 to 13, wherein the first connection terminal and the second connection terminal are electrically connected.   An inkjet printer comprising the inkjet head according to any one of claims 1 to 14, wherein ink is ejected from the inkjet head toward a recording medium. A method for manufacturing an inkjet head, comprising an adhesive step of bonding an inkjet substrate that ejects ink based on a drive signal and a wiring substrate that supplies the drive signal to the inkjet substrate with an adhesive member,
The inkjet substrate is
A pressure chamber containing ink, a nozzle communicating with the pressure chamber, a circulation channel for circulating non-ejection ink other than the ink ejected from the nozzle, and the circulation channel from the wiring board side A head substrate having a flexible region;
A piezoelectric body that is supported by the head substrate and applies a pressure to the ink in the pressure chamber;
Individual electrodes for driving the piezoelectric body,
A first wiring electrically connected to the individual electrode,
The wiring board includes a second wiring for supplying the drive signal to the individual electrode,
The bonding step is
On the inkjet substrate, the adhesive member is arranged in a first region that overlaps with at least a part of the circulation channel and a second region that overlaps with the outside of the circulation channel. Process,
By relatively pressing the wiring substrate against the inkjet substrate via the adhesive member, while electrically connecting the first wiring and the second wiring at least in the first region, A second step of adhering the inkjet substrate and the wiring substrate with the adhesive member located in the first region and the second region. . The piezoelectric body is supported by the head substrate and is located above the pressure chamber,
In the head substrate, the circulation channel is in communication with the pressure chamber via an individual channel,
In the first step, on the inkjet substrate, the first region and the region of the second region located on the piezoelectric body side with respect to the first region and the piezoelectric body are opposite to each other. The method for manufacturing an inkjet head according to claim 16, wherein the adhesive member is arranged in both of the regions located on the side . The piezoelectric body is supported by the head substrate and is located above the pressure chamber,
In the head substrate, the circulation channel is in communication with the pressure chamber via an individual channel,
In the first step, on the inkjet substrate, the first region and the region of the second region located on the piezoelectric body side with respect to the first region and the piezoelectric body are opposite to each other. The method for manufacturing an inkjet head according to claim 16, wherein the adhesive member is arranged in either one of the regions located on the side . The adhesive member includes an anisotropic conductive adhesive having conductive particles,
The method for manufacturing an inkjet head according to claim 16, wherein the anisotropic conductive adhesive is disposed in the first region in the first step.   20. The method of manufacturing an inkjet head according to claim 19, wherein in the first step, the anisotropic conductive adhesive is further arranged in the second region.   21. In the first step, the anisotropic conductive adhesive is arranged on the inkjet substrate so as to be continuous from the first region to the second region. Manufacturing method of inkjet head.   22. The method for manufacturing an inkjet head according to claim 19, wherein the anisotropic conductive adhesive is an anisotropic conductive film or an anisotropic conductive paste. The adhesive member further includes a non-conductive adhesive,
20. The method of manufacturing an inkjet head according to claim 19, wherein in the first step, the non-conductive adhesive is arranged in the second region. The adhesive member includes a non-conductive adhesive,
In the first step, disposing the non-conductive adhesive in the first region,
In the second step, by relatively pressing the wiring board against the inkjet substrate, the first wiring and the second wiring are brought into direct contact with each other at least in the first region, and In the first area, the inkjet board and the wiring board are bonded by the non-conductive adhesive located around the first wiring and the second wiring that are in direct contact with each other. The method for manufacturing an inkjet head according to claim 16.   The method of manufacturing an inkjet head according to claim 24, wherein in the first step, the non-conductive adhesive is further arranged in the second region.   26. In the first step, the non-conductive adhesive is arranged on the inkjet substrate so as to be continuous from the first region to the second region. Inkjet head manufacturing method.   27. The method for manufacturing an inkjet head according to claim 23, wherein the non-conductive adhesive is a non-conductive film or a non-conductive paste. The head substrate has a plurality of the pressure chambers,
28. The method according to claim 16, wherein the circulation flow path is a common flow path that communicates with each of the pressure chambers and circulates the non-ejection ink.   In the second step, by pressing the wiring board relative to the inkjet substrate, the first connection terminal included in the first wiring and the second connection terminal included in the second wiring. 29. The method of manufacturing an inkjet head according to claim 16, wherein the terminal is electrically connected at a position overlapping at least a part of the circulation flow path.

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