JP6044200B2 - Liquid ejector - Google Patents

Description

The present invention relates to a liquid jet equipment.

  2. Description of the Related Art Conventionally, a liquid ejecting apparatus having a piezoelectric actuator that imparts ejection energy to a liquid is known. For example, Patent Document 1 discloses an inkjet head having a flow path forming substrate in which a plurality of pressure chambers communicating with a plurality of nozzles are formed, and a piezoelectric actuator provided on the flow path forming substrate. Yes.

  The piezoelectric actuator has a plurality of piezoelectric elements disposed on the surface of an elastic film covering the plurality of pressure chambers so as to face the plurality of pressure chambers, respectively. The piezoelectric element has a piezoelectric layer, an upper electrode film, and a lower electrode film. The piezoelectric layer is formed on the surface of an elastic film made of silicon dioxide by a film forming technique such as a sol-gel method or a MOD method.

  By the way, in the piezoelectric actuator described above, it is preferable that the piezoelectric layer is thin from the viewpoint of further improving the driving efficiency of the piezoelectric element and realizing high-speed driving. However, the thinner the piezoelectric layer, the stronger the electric field applied to the piezoelectric layer. When the piezoelectric layer absorbs atmospheric moisture, a large leakage current is generated between the electrode films, resulting in dielectric breakdown. There is a risk of reaching. Therefore, it is required to shield the piezoelectric element from the atmosphere and to prevent moisture. In the ink jet head of Patent Document 1, a moisture-resistant protective film that individually covers a plurality of piezoelectric elements is formed on the flow path forming substrate, thereby preventing the piezoelectric elements from coming into contact with the atmosphere.

JP 2001-138511 A

  In the piezoelectric actuator of Patent Document 1, after forming a plurality of piezoelectric elements, it is necessary to separately form a moisture-proof protective film so as to cover each of the plurality of piezoelectric elements. Accordingly, the number of members constituting the piezoelectric actuator increases, and the number of unnecessary processes increases, resulting in an increase in manufacturing cost.

  An object of the present invention is to realize moisture-proofing of a piezoelectric element without adding a special member.

A liquid ejecting apparatus according to a first aspect of the present invention includes a flow path structure in which a liquid flow path including a plurality of nozzles and a plurality of pressure chambers communicating with the plurality of nozzles is formed, and one surface of the flow path structure to a plurality of piezoelectric elements disposed to face each with the plurality of pressure chambers, and a driver IC for driving the plurality of piezoelectric elements, the said one surface of the front Kiryuro structure, wherein A plurality of connection terminals including a plurality of drive terminals respectively connected to the plurality of piezoelectric elements are arranged in a peripheral region of the plurality of piezoelectric elements, and the driver IC covers the plurality of piezoelectric elements so as to cover the plurality of piezoelectric elements. A plurality of bumps that are disposed to face the one surface of the road structure and project to the other side of the driver IC and the flow path structure are provided, and a plurality of bumps included in the plurality of bumps The first bumps By connecting the driver IC and the plurality of connection terminals arranged in the peripheral region of the plurality of piezoelectric elements, the plurality of piezoelectric elements are surrounded by the plurality of first bumps, An insulating sealing material is filled between the bumps, the plurality of pressure chambers are arranged in a predetermined direction along the one surface of the flow path structure, and the driver IC has a rectangular planar shape And the long side of the channel structure is disposed to face the one surface in a state along the predetermined direction, and around the plurality of piezoelectric elements on the one surface of the channel structure. Among the regions, the plurality of driving terminals are arranged in a region along the long side of the driver IC, and the one surface of the flow path structure is a region around the plurality of piezoelectric elements. In the region along the short side of the driver IC, the drive It is characterized in that the connection terminals except use terminal is disposed.
A liquid ejecting apparatus according to a second aspect of the present invention includes a flow path structure in which a liquid flow path including a plurality of nozzles and a plurality of pressure chambers communicating with the plurality of nozzles is formed, and one surface of the flow path structure A plurality of piezoelectric elements disposed to face the plurality of pressure chambers, and a driver IC that drives the plurality of piezoelectric elements, and the surface of the flow path structure includes the plurality of the plurality of piezoelectric elements. A plurality of connection terminals including a plurality of drive terminals respectively connected to the piezoelectric elements are arranged in a peripheral region of the plurality of piezoelectric elements, and the driver IC covers the plurality of piezoelectric elements so as to cover the plurality of piezoelectric elements. A plurality of bumps that are disposed to face the one surface of the structure and project to the other side of the driver IC and the flow path structure are provided, and a plurality of first bumps included in the plurality of bumps are provided. With one bump, By connecting the driver IC and the plurality of connection terminals arranged in the peripheral region of the plurality of piezoelectric elements, the plurality of piezoelectric elements are surrounded by the plurality of first bumps, An insulating sealing material is filled between the bumps, and the plurality of bumps further includes a second bump disposed between the plurality of first bumps, and the second bump includes the second bump, The one surface of the channel structure is bonded to a region where the connection terminal is not disposed, and the sealing material is filled between the first bump and the second bump. Is.
A liquid ejecting apparatus according to a third aspect of the present invention includes a flow path structure in which a liquid flow path including a plurality of nozzles and a plurality of pressure chambers communicating with the plurality of nozzles is formed, and one surface of the flow path structure A plurality of piezoelectric elements disposed to face the plurality of pressure chambers, and a driver IC that drives the plurality of piezoelectric elements, and the surface of the flow path structure includes the plurality of the plurality of piezoelectric elements. A plurality of connection terminals including a plurality of drive terminals respectively connected to the piezoelectric elements are arranged in a peripheral region of the plurality of piezoelectric elements, and the driver IC covers the plurality of piezoelectric elements so as to cover the plurality of piezoelectric elements. A plurality of bumps that are disposed to face the one surface of the structure and project to the other side of the driver IC and the flow path structure are provided, and a plurality of first bumps included in the plurality of bumps are provided. 1 bump is the driver By being provided along the entire periphery of the edge of C, the plurality of first bumps connect the driver IC and the plurality of connection terminals arranged in the peripheral region of the plurality of piezoelectric elements, The plurality of piezoelectric elements are surrounded by the plurality of first bumps, and an insulating sealing material is filled between the plurality of first bumps.
A liquid ejecting apparatus according to a fourth aspect of the present invention includes a flow path structure in which a liquid flow path including a plurality of nozzles and a plurality of pressure chambers communicating with the plurality of nozzles is formed, and one surface of the flow path structure A plurality of piezoelectric elements disposed to face the plurality of pressure chambers, and a driver IC that drives the plurality of piezoelectric elements, and the surface of the flow path structure includes the plurality of the plurality of piezoelectric elements. A plurality of connection terminals including a plurality of drive terminals respectively connected to the piezoelectric elements are arranged in a peripheral region of the plurality of piezoelectric elements, and the driver IC covers the plurality of piezoelectric elements so as to cover the plurality of piezoelectric elements. A plurality of bumps that are disposed to face the one surface of the structure and project to the other side of the driver IC and the flow path structure are provided, and a plurality of first bumps included in the plurality of bumps are provided. With one bump, By connecting the driver IC and the plurality of connection terminals arranged in the peripheral region of the plurality of piezoelectric elements, the plurality of piezoelectric elements are surrounded by the plurality of first bumps, It is characterized in that an insulating sealing material is filled between the bumps.

In the present invention, the driver IC is disposed on one surface of the flow path structure so as to cover the plurality of piezoelectric elements. When the driver IC and the plurality of connection terminals formed in the peripheral region of the piezoelectric element on one surface of the flow path structure are connected by the plurality of first bumps, the plurality of first bumps cause a plurality of connection terminals. The piezoelectric element is surrounded. Further, an insulating sealing material is filled between the plurality of first bumps. Accordingly, the plurality of piezoelectric elements are sealed by the driver IC, the plurality of first bumps, and the sealing material between the plurality of first bumps, and the plurality of piezoelectric elements are shielded from the atmosphere. As described above, since the driver IC and the bumps for connecting the driver IC to the plurality of connection terminals on the flow channel structure side are used to cover the plurality of piezoelectric elements, a dedicated member is added to the component. Without increasing the score, the piezoelectric element can be shielded from the atmosphere and moisture-proof.
According to the first invention, when the planar shape of the driver IC is rectangular, a plurality of driving terminals respectively corresponding to a plurality of pressure chambers (a plurality of piezoelectric elements) are arranged along the long side. By doing so, the long side having a large length to be sealed can be reliably sealed. On the other hand, since the short side of the driver IC can be sealed with a smaller number of bumps than the long side, connection terminals other than the driving terminals are arranged on the short side.
Further, according to the second invention, the first bump contributes to driving the piezoelectric element by electrically connecting the driver IC and the connection terminal on the flow path structure side. The number and the interval may not be set freely due to restrictions such as the size and number of piezoelectric elements. However, if the interval between the first bumps is large, it becomes difficult to hold the sealing material between the adjacent first bumps, which makes sealing difficult. In this regard, in the second invention, between the plurality of first bumps, a so-called dummy second bump bonded to a region where the connection terminal is not disposed is disposed. Accordingly, even when the interval between the adjacent first bumps is wide, the interval between the bumps can be reduced by arranging the second bump between them, so that the gap between the bumps can be reliably sealed with a sealing material. It can be sealed.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the connection terminal is located outside a region of the one surface of the flow path structure that faces the pressure chamber. It is characterized by being arranged.

  When the driver IC is pressed against the flow channel structure and connected to the plurality of connection terminals, the pressed channel portion is not opposed to the pressure chamber, so that the pressing force can be withstood. Further, the flow path structure is not easily bent at the time of joining, and the piezoelectric element is prevented from being damaged by the bending of the flow path structure.

The liquid ejecting apparatus according to a sixth aspect is the liquid ejecting apparatus according to the fifth aspect , wherein the bump is bonded to a region of the one surface of the flow path structure that faces the partition wall that separates the plurality of pressure chambers. It is characterized by being.

  Since the driver IC is pressed through the bumps even in the region where the plurality of pressure chambers are arranged, the driver IC can be pressed firmly against the flow path structure and reliably bonded. Further, when the driver IC is pressed only to the peripheral area of the plurality of piezoelectric elements, there is a possibility that the flow path structure warps to the driver IC side in the inner area (piezoelectric element arrangement area). In the present invention, since a pressing force acts on the inner region of one surface of the flow path structure, warpage is prevented.

The piezoelectric actuator as reference examples, a plurality of piezoelectric elements disposed on one surface of the substrate, and a driver IC for driving the plurality of piezoelectric elements, the said one surface of the pre-Symbol substrate, said plurality of piezoelectric A plurality of connection terminals including a plurality of drive terminals respectively connected to the elements are arranged in a peripheral region of the plurality of piezoelectric elements, and the driver IC covers the plurality of piezoelectric elements so as to cover the plurality of piezoelectric elements. A plurality of bumps that are arranged to face the surface and project to the other side of the driver IC and the flow path structure are provided, and a plurality of first bumps included in the plurality of bumps, By connecting the driver IC and the plurality of connection terminals arranged in the peripheral region of the plurality of piezoelectric elements, the plurality of piezoelectric elements are connected by the driver IC and the plurality of first bumps. Enclosed, sealant insulation between the plurality of first bump is characterized in that it is filled.

In the piezoelectric actuator of this reference example , the plurality of piezoelectric elements are sealed by the driver IC, the plurality of first bumps, and the sealing material between the plurality of first bumps. Accordingly, the piezoelectric element can be shielded from the atmosphere and moisture-proof without adding a dedicated member and increasing the number of parts.

  According to the present invention, the plurality of piezoelectric elements are sealed by the driver IC, the plurality of first bumps, and the sealing material between the plurality of first bumps. As described above, a plurality of piezoelectric elements can be covered by using the driver IC and bumps for connecting the driver IC to the plurality of connection terminals on the flow channel structure side, so that a dedicated member is added. Thus, the piezoelectric element can be shielded from the atmosphere and moisture-proof without increasing the number of parts.

1 is a schematic plan view of an ink jet printer according to an embodiment. It is a top view of an inkjet head. It is a top view of an inkjet head (state where a driver IC is not attached). It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. It is a top view of the ink jet head concerning a change form. It is the VII-VII sectional view taken on the line of FIG. It is a top view of the ink-jet head concerning another modification. It is a top view of the ink-jet head concerning another modification. FIG. 10 is a sectional view taken along line XX in FIG. 9. It is a top view of the ink-jet head concerning another modification. It is a top view of the ink jet head (state where driver IC is not attached) concerning another modification.

  Next, an embodiment of the present invention will be described. FIG. 1 is a schematic plan view of the ink jet printer of the present embodiment. First, a schematic configuration of the inkjet printer 1 will be described with reference to FIG. In the following, the front side in FIG. 1 is defined as the upper side, and the other side of the page is defined as the lower side, and the explanation will be made using direction words “up” and “down” as appropriate. As shown in FIG. 1, the inkjet printer 1 includes a platen 2, a carriage 3, an inkjet head 4, a transport mechanism 5, and the like.

  On the upper surface of the platen 2, a recording sheet 100 as a recording medium is placed. In addition, above the platen 2, two guide rails 10 and 11 extending in parallel with the horizontal direction (scanning direction) in FIG. 1 are provided. The carriage 3 is configured to reciprocate in the scanning direction along the two guide rails 10 and 11 in a region facing the platen 2. In addition, an endless belt 14 wound between two pulleys 12 and 13 is connected to the carriage 3. When the endless belt 14 is driven by the carriage drive motor 15, the carriage 3 is connected to the endless belt 14. 14 moves in the scanning direction.

  The ink jet head 4 (liquid ejecting apparatus) is attached to the carriage 3 and moves in the scanning direction together with the carriage 3. The inkjet head 4 is connected to an ink cartridge (not shown) mounted on the printer 1 by a tube. A plurality of nozzles 16 are formed on the lower surface of the inkjet head 4 (the surface on the other side of the paper in FIG. 1). The inkjet head 4 ejects the ink supplied from the ink cartridge to the recording paper 100 placed on the platen 2 from the plurality of nozzles 16.

  The transport mechanism 5 has two transport rollers 18 and 19 arranged so as to sandwich the platen 2 in the transport direction, and these two transport rollers 18 and 19 are rotationally driven by a motor (not shown). The transport mechanism 5 transports the recording paper 100 placed on the platen 2 in the transport direction by two transport rollers 18 and 19.

  The ink jet printer 1 ejects ink from the ink jet head 4 which reciprocates in the scanning direction (left and right direction in FIG. 1) together with the carriage 3 onto the recording paper 100 placed on the platen 2. At the same time, the recording paper 100 is transported in the transport direction (downward in FIG. 1) by the two transport rollers 18 and 19. Through the above operation, images, characters, and the like are recorded on the recording paper 100.

  Next, the inkjet head 4 will be described. FIG. 2 is a plan view of the inkjet head. FIG. 3 is a plan view of the inkjet head in a state where the driver IC shown in FIG. 2 is not attached. 4 is a cross-sectional view taken along line IV-IV in FIG. In FIG. 4, the ink filled in the ink flow path is indicated by the symbol “I”. As shown in FIGS. 2 to 4, the inkjet head 4 includes a flow path unit 20 (flow path structure), a piezoelectric actuator 21, a driver IC 46, and the like.

  As shown in FIG. 4, the flow path unit 20 has a structure in which five plates 30 to 34 each having a large number of flow path forming holes are laminated. When these five plates 30 to 34 are laminated, a large number of flow path forming holes communicate with each other, whereby the flow path unit 20 has the ink flow path as described below. The material of the five plates 30 to 34 is not particularly limited, and may be a metal plate such as stainless steel or nickel alloy steel. Alternatively, it may be a silicon single crystal substrate.

  As shown in FIG. 2, an ink supply hole 26 connected to an ink cartridge (not shown) is formed on the upper surface of the flow path unit 20. Two manifolds 25 each extending in the transport direction are formed inside the flow path unit 20. The two manifolds 25 are commonly connected to one ink supply hole 26, and the ink supplied from the ink cartridge is supplied to each of the two manifolds 25.

  As shown in FIGS. 2 to 4, the flow path unit 20 is communicated with the plurality of nozzles 16 formed on the lowermost nozzle plate 34 and opening on the lower surface of the flow path unit 20, respectively. The plurality of pressure chambers 24 are provided. As shown in FIGS. 2 and 3, the plurality of nozzles 16 are arranged in two rows along the transport direction on the lower surface of the flow path unit 20 (the surface on the opposite side of the paper surface in FIGS. 2 and 3). The arrangement of the plurality of nozzles 16 is a so-called staggered arrangement in which the positions of the nozzles 16 are shifted from each other in the conveyance direction between the two right and left nozzle rows.

  Each of the plurality of pressure chambers 24 has a substantially elliptical planar shape that is long in the scanning direction. The plurality of pressure chambers 24 are arranged in a plane, and the plurality of pressure chambers 24 are covered with a diaphragm 30 from above. Further, the plurality of pressure chambers 24 are arranged in two rows in a staggered manner along the transport direction corresponding to the plurality of nozzles 16, respectively. Each pressure chamber 24 communicates with the corresponding nozzle 16 at one longitudinal end thereof. The arrangement relationship between the pressure chambers 24 and the nozzles 16 is reversed between the two right and left pressure chamber rows. That is, as shown in FIGS. 2 to 4, in the left pressure chamber row, the nozzle 16 corresponding to the right end portion in the longitudinal direction of each pressure chamber 24 communicates. On the other hand, in the right pressure chamber row, the nozzle 16 corresponding to the left end in the longitudinal direction of each pressure chamber 24 communicates. As a result, as shown in FIGS. 2 and 3, two corresponding nozzle rows are arranged inside the two pressure chamber rows.

  The two pressure chamber rows are arranged at positions overlapping with the two manifolds 25, and each pressure chamber 24 communicates with the manifold 25 located immediately below. As a result, as shown in FIG. 4, the flow path unit 20 is formed with a plurality of individual ink flow paths 27 that branch from the manifold 25 and reach the nozzles 16 through the pressure chambers 24.

  Next, the piezoelectric actuator 21 will be described. The piezoelectric actuator 21 is disposed on the upper surface of the diaphragm 30 of the flow path unit 20. As shown in FIGS. 2 to 4, the piezoelectric actuator 21 includes a piezoelectric body 40, a plurality of drive electrodes 42, and a common electrode 43.

  As shown in FIG. 4, an insulating film 44 made of an insulating material such as a synthetic resin material is formed on almost the entire surface of the vibration plate 30. Two piezoelectric bodies 40 formed in a rectangular shape are disposed on the upper surface of the diaphragm 30 covered with the insulating film 44. The two piezoelectric bodies 40 are arranged so that their longitudinal directions are parallel to the arrangement direction (conveying direction) of the pressure chambers 24 so as to cover the two pressure chamber rows, respectively. The piezoelectric body 40 is made of a piezoelectric material mainly composed of ferroelectric lead zirconate titanate (PZT), which is a solid solution of lead titanate and lead zirconate. The piezoelectric body 40 can be directly formed on the upper surface of the diaphragm 30 covered with the insulating film 44 by a known film forming technique such as a sputtering method or a sol-gel method. Alternatively, it can be formed by baking an unfired thin green sheet and then attaching it to the diaphragm 30.

  The plurality of drive electrodes 42 are formed in regions of the lower surface of the piezoelectric body 40 facing the plurality of pressure chambers 24, respectively. Each drive electrode 42 has a substantially elliptical planar shape that is slightly smaller than the pressure chamber 24, and is disposed so as to face the substantially central portion of the corresponding pressure chamber 24. The drive electrode 42 is electrically insulated from the diaphragm 30 by the insulating film 44.

  A plurality of drive terminals 45 are connected to the plurality of drive electrodes 42, respectively. Each driving terminal 45 is drawn out from the corresponding driving electrode 42 on the insulating film 44 to the region that is in the longitudinal direction and opposite to the nozzle 16 (outside) and does not face the pressure chamber 24. 3 and exposed from the piezoelectric body 40 as shown in FIG. The plurality of drive terminals 45 are arranged along the transport direction on both sides of the two piezoelectric bodies 40 in the scanning direction. A driver IC 46 to be described later is connected to the plurality of driving terminals 45, and a predetermined driving voltage is applied from the driver IC 46 to each of the plurality of driving electrodes 42.

  The common electrode 43 is formed so as to cover the entire upper surface of the piezoelectric bodies 40 across the two piezoelectric bodies 40. In FIG. 3, the common electrode 43 covering the two piezoelectric bodies 40 is hatched. Specifically, the common electrode 43 includes two electrode portions 43a formed over the entire upper surface of the two piezoelectric bodies 40, and from the two electrode portions 43a to one side in the arrangement direction of the pressure chambers 24 (upstream in the transport direction). The first connection portion 43 b is drawn out and formed on the upper surface of the diaphragm 30, and the second connection portion 43 c is formed in a region between the two piezoelectric bodies 40 on the upper surface of the vibration plate 30.

  The first connection portion 43 b extends in the scanning direction along the short sides of the two rectangular piezoelectric bodies 40. The second connection portion 43c extends in the transport direction along the long sides of the two rectangular piezoelectric bodies 40. The first connection portion 43 b and the second connection portion 43 c are electrically insulated from the diaphragm 30 by the insulating film 44. Further, since both the first connection portion 43 b and the second connection portion 43 c are formed on the upper surface of the diaphragm 30, the first connection portion 43 b and the second connection portion 43 c are at a position lower than the two electrode portions 43 a formed on the upper surface of the piezoelectric body 40. As shown in the cross section of FIG. 4, the common electrode 43 has a shape that is locally recessed in the second connection portion 43 c. The first connection portion 43b is on the upstream side in the transport direction of the upper surface of the diaphragm 30 with respect to the region where the plurality of pressure chambers 24 are formed. The second connection portion 43 c faces the partition wall portion 20 a that separates the two rows of pressure chambers 24 of the flow path unit 20. That is, the first connection portion 43 b and the second connection portion 43 c are both disposed in a region on the upper surface of the diaphragm 30 that does not face the pressure chamber 24.

  Both the first connection portion 43b located on the upstream side in the transport direction with respect to the two piezoelectric bodies 40 and the second connection portion 43c located between the two piezoelectric bodies 40 are connected to a driver IC 46, which will be described later. Conducts with the ground wiring. As a result, the common electrode 43 is always held at the ground potential.

  As shown in FIG. 4, a portion of the piezoelectric body 40 sandwiched between one drive electrode 42 and the electrode portion 43 a of the common electrode 43 (hereinafter, also referred to as “piezoelectric element 41”) will be described below. It is deformed when a driving voltage is applied to the driving electrode 42, and becomes a portion that applies ejection energy to the ink in one pressure chamber 24. In the present embodiment, one piezoelectric body 40 is disposed across the plurality of pressure chambers 24 belonging to one row of pressure chambers, whereby a plurality of piezoelectric elements 41 corresponding to one row of pressure chambers are integrated. It has been configured. Each of the plurality of piezoelectric elements 41 is polarized in the thickness direction.

  When a drive voltage is applied from the driver IC 46 to the drive electrode 42, a potential difference is generated between the drive electrode 42 and the common electrode 43 of the ground potential, and the portion of the piezoelectric body 40 between these two electrodes 42 and 43. An electric field in the thickness direction acts on (piezoelectric element 41). Since the direction of the electric field is parallel to the polarization direction of the piezoelectric element 41, the piezoelectric element 41 expands in the thickness direction and contracts in the plane direction. Due to the contraction of the piezoelectric element 41, the vibration plate 30 covering the pressure chamber 24 is bent so as to protrude toward the pressure chamber 24, and the volume of the pressure chamber 24 is reduced. At that time, pressure (ejection energy) is applied to the ink in the pressure chamber 24, and ink droplets are ejected from the nozzles 16.

  Next, the driver IC 46 will be described. Various circuits for driving the piezoelectric actuator are incorporated in the driver IC 46. As shown in FIG. 2, the driver IC 46 has a rectangular planar shape. The driver IC 46 is disposed so as to face the upper surface of the diaphragm 30 of the flow path unit 20 with its long side along the arrangement direction of the pressure chambers 24 and covers the two piezoelectric bodies 40 from above. Joined to the diaphragm 30.

  As described above, a plurality of drive terminals 45 respectively drawn from the plurality of drive electrodes 42 are disposed on the upper surface of the diaphragm 30 on both sides in the scanning direction of the two piezoelectric bodies 40. . Further, the first connection portion 43 b of the common electrode 43 is disposed on the upper surface of the vibration plate 30 in the region upstream of the two piezoelectric bodies 40 in the transport direction. Further, as shown in FIGS. 2 and 3, a plurality of input terminals 47 (power input terminal 47a, ground input terminal 47b, and signal input terminal 47c) are provided in a region downstream of the two piezoelectric bodies 40 in the transport direction. They are arranged side by side. The plurality of input terminals 47 are connected to a control board (not shown) that controls the operation of the inkjet head 4.

  That is, a plurality of drive terminals 45, a first connection portion 43 b of the common electrode 43, and a plurality of input terminals 47 are formed in the area around the two piezoelectric bodies 40 on the upper surface of the vibration plate 30. In addition, a second connection portion 43 c of the common electrode 43 is disposed in the region between the two piezoelectric bodies 40 on the upper surface of the vibration plate 30. Hereinafter, for convenience of explanation, the plurality of drive terminals 45, the first connection portion 43b, the second connection portion 43c, and the plurality of input terminals 47 of the common electrode 43 are collectively referred to as “a plurality of connection terminals 50”.

  On the other hand, on the lower surface (connection surface) of the driver IC 46 facing the diaphragm 30, a plurality of bumps 51 made of a conductive material connected to the plurality of connection terminals 50 described above are disposed below (the paper surface of FIG. 2). It is provided to protrude on the other side. First, as shown in FIG. 2, a plurality of drive bumps 51 a connected to a plurality of drive terminals 45 are provided at two edges along the two long sides 46 a and 46 b of the rectangular driver IC 46. ing. A plurality of first common electrode bumps 51 b connected to the first connection portion 43 b of the common electrode 43 are provided on the edge portion along one short side 46 c of the driver IC 46. A plurality of input bumps 51 c connected to the plurality of input terminals 47 are provided on the edge portion along the other short side 46 d of the driver IC 46. Further, a plurality of second common electrode bumps 51 d connected to the second connection portion 43 c of the common electrode 43 are also provided in the center portion of the driver IC 46.

  The driver IC 46 is arranged on the upper surface of the diaphragm 30 with the long sides 46 a and 46 b parallel to the transport direction, and the plurality of bumps 51 described above are formed on the upper surface of the diaphragm 30. Each is connected to a terminal 50. The driver IC 46 is connected to the control board via a plurality of input terminals 47 (power input terminal 47a, ground input terminal 47b, signal input terminal 47c), so that power supply from the control board side, ground connection, and A control signal is input. The driver IC 46 is connected to the plurality of drive electrodes 42 via the plurality of drive terminals 45 and also to the common electrode 43. As a result, the driver IC 46 individually applies a driving voltage to the plurality of driving electrodes 42 while holding the common electrode 43 at the ground potential.

  2 and 3, bumps 51a, 51b, 51c provided along the entire periphery of the edge of the driver IC 46 among the plurality of bumps 51 provided in the driver IC 46 (the present invention). The first bump) surrounds the two piezoelectric bodies 40 (a plurality of piezoelectric elements 41). 5 is a cross-sectional view taken along line VV in FIG. As shown in FIGS. 4 and 5, a sealing material 52 made of an insulating material such as a synthetic resin is filled between the plurality of bumps 51 that connect the driver IC 46 and the plurality of connection terminals 50. As a result, the adjacent bumps 51 are insulated and the gaps between the bumps 51 are completely sealed. Accordingly, the plurality of piezoelectric elements 41 are hermetically sealed from the atmosphere by the driver IC 46, the plurality of bumps 51a, 51b, 51c (first bump), and the sealing material 52 between the plurality of bumps 51a, 51b, 51c. Is done.

  The electrical connection between the driver IC 46 and the plurality of connection terminals 50 on the diaphragm 30 side is performed as follows, for example. First, a plurality of anisotropic conductive materials such as an anisotropic conductive film (ACF) and an anisotropic conductive paste (ACP) in which conductive particles are dispersed in a thermosetting resin are formed on the upper surface of the diaphragm 30. It arrange | positions so that the connection terminal 50 may be covered. Next, the driver IC 46 is pressed against the diaphragm 30 while the flow path unit 20 is heated. At this time, a large pressure acts on the anisotropic conductive material locally between the bump 51 on the driver IC 46 side and the connection terminal 50 to push the thermosetting resin to the side, and the remaining conductive particles cause the bump 51. And the connection terminal 50 becomes conductive. At the same time, the thermosetting resin is cured by heating, and the driver IC 46 and the flow path unit 20 are mechanically joined. Note that almost no pressure acts on the portion of the anisotropic conductive material where the bumps 51 are not pressed, and the insulation is maintained. In the present embodiment, when the driver IC 46 is pressed, the anisotropic conductive material that has entered between adjacent bumps 51 functions as the above-described sealing material 52 that insulates between the bumps 51 and seals the gap. To do.

  The bumps 51 on the driver IC 46 side and the connection terminals 50 on the flow path unit 20 side may be joined with solder. In this case, after soldering, a sealing material 52 made of a liquid curable resin such as an epoxy resin is injected between the bumps 51 and cured.

  As described above, in the present embodiment, a plurality of piezoelectric elements are utilized by using the driver IC 46 for driving the piezoelectric actuator 21 and the bumps 51 for connecting the driver IC 46 to the plurality of connection terminals 50 on the flow path unit 20 side. 41 is covered and shielded from the atmosphere. Therefore, the plurality of piezoelectric elements 41 can be reliably moisture-proof without adding a dedicated member and increasing the number of parts.

  2 to 4, a plurality of connection terminals 50 on the diaphragm 30 side (a plurality of drive terminals 45, a first connection portion 43b of the common electrode 43, a second connection portion 43c, and a plurality of connection terminals 50). The input terminal 47) is formed outside the region of the diaphragm 30 that faces the pressure chamber 24. Therefore, when the driver IC 46 is pressed against the flow path unit 20 and joined to the plurality of connection terminals 50, the portion of the diaphragm 30 to which the plurality of bumps are pressed can withstand the pressing force. Therefore, the vibration plate 30 is unlikely to be bent when the driver IC 46 is joined, and the piezoelectric body 40 (piezoelectric element 41) is prevented from being damaged by the bending of the vibration plate 30.

  Further, a second connection portion 43c of the common electrode 43 is formed in a region facing the partition wall portion 20a that separates the two rows of pressure chambers 24 of the diaphragm 30, and the second common electrode bump 51d is formed on the second connection portion 43c. Are joined. That is, since the driver IC 46 is pressed through the bumps 51d even in the region where the plurality of pressure chambers 24 are disposed, the driver IC 46 can be pressed firmly against the flow path unit 20 and reliably bonded. When the driver IC 46 is pressed only on the area around the piezoelectric body 40, the diaphragm 30 warps upward (on the driver IC 46 side) in the inner area (area where the piezoelectric body 40 is disposed). There is a risk of it. On the other hand, in this embodiment, since a pressing force acts also on the inner region of the diaphragm 30, warpage is prevented.

  In order to securely block the piezoelectric body 40 from the atmosphere, it is necessary to completely seal the gaps between the bumps 51a, 51b, 51c (first bumps) surrounding the piezoelectric body 40 with the sealing material 52. If the gap between these bumps is large, it is difficult to hold the sealing material 52, and sealing may be insufficient. In this regard, in the present embodiment, among the peripheral regions of the two piezoelectric bodies 40, the regions along the long sides 46a and 46b of the driver IC 46 correspond to the plurality of pressure chambers 24 (the plurality of drive electrodes 42), respectively. A large number of drive terminals 45 are arranged. Thereby, the long side where the length which should be sealed is large can be sealed reliably. On the other hand, the short side of the driver IC 46 can be sealed with a smaller number of bumps than the long side. Accordingly, the input terminals 47 having a smaller number than the drive terminals 45 are arranged in a region along one short side 46 d of the driver IC 46 in the peripheral region of the piezoelectric body 40. Note that the number of the first common electrode bumps 51b does not need to be increased as much as the first connection portion 43b arranged on the other short side 46c side of the driver IC 46, considering only the conduction with the driver IC 46. . However, from the viewpoint of ensuring sealing of the short side 46c on the other side, it is preferable to provide the same number of first common electrode bumps 51b as the plurality of input bumps 51c.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

1] The arrangement of the plurality of connection terminals 50 connected to the driver IC 46 only needs to be arranged so that at least some of the connection terminals 50 surround the plurality of piezoelectric elements 41, and is not limited to a specific arrangement.

  For example, as shown in FIGS. 6 and 7, even if the driver IC 46 is connected to the common electrode 43 by the bump 51b only in the first connection portion 43b formed on the upstream side in the transport direction from the two piezoelectric bodies 40. Good. That is, the bump 51 may not be bonded to a region between the two piezoelectric bodies 40 facing the partition wall portion 20a that separates the pressure chamber 24.

  Or conversely, as shown in FIG. 8, the driver IC 46 may be connected to the common electrode 43 by the bump 51 d only at the second connection portion 43 c between the two piezoelectric bodies 40. In this case, on the short side 46c side of the driver IC 46, other connection terminals 50 such as a plurality of input terminals 47 other than for connection of the common electrode 43 can be arranged.

  In the embodiment, as shown in FIG. 2, the plurality of drive terminals 45 are arranged on the long sides 46 a and 46 b of the driver IC 46. However, when the number of connection terminals other than the drive terminals 45 is large. The drive terminal 45 may be disposed on the short side of the driver IC 46, and the connection terminal 50 other than the drive terminal 45 may be disposed on the long side of the driver IC 46.

2] In the embodiment, the plurality of bumps 51 provided in the driver IC 46 are all electrically connected to the plurality of connection terminals 50 formed on the flow path unit 20 side. In addition, so-called dummy bumps may be included that are joined to regions where the connection terminals 50 are not disposed.

  For example, as shown in FIGS. 9 and 10, the driver IC 46 may be provided with dummy bumps 51e (second bumps) arranged between the plurality of drive bumps 51a. As shown in FIG. 10, the dummy bump is directly bonded to the insulating film 44 that covers the vibration plate 30 and is not electrically connected to the connection terminal 50 such as the drive terminal 45. Further, a sealing material 52 is filled between the drive bump 51a and the dummy bump 51e.

  The bumps 51 connected to the connection terminals 50, such as the drive bumps 51a, connect the driver IC 46 and the connection terminals 50 and contribute to driving the piezoelectric element 41. The interval between the bumps 51 is piezoelectric. Due to restrictions on the size and number of elements 41, it may not be possible to set them freely. However, if the interval between the bumps 51 is large, it becomes difficult to hold the sealing material 52 between the adjacent bumps 51, which makes sealing difficult. In this regard, in the configuration of FIGS. 9 and 10, dummy bumps 51e can be arranged between the plurality of drive bumps 51a to reduce the interval between the bumps 51. It can be surely sealed.

  In FIG. 9, the drive bumps 51a and the dummy bumps 51e are arranged on a straight line. However, as shown in FIG. 11, the drive bumps 51a and the dummy bumps 51e are arranged with their positions shifted in the scanning direction. These bumps 51 may be arranged in a staggered pattern. This arrangement is suitable when the arrangement interval of the drive bumps 51a is small and it is difficult to arrange the dummy bumps 51e between them. Further, the thickness of the sealing material 52 held between the bumps 51 can be increased as compared with the configuration in which the drive bumps 51a and the dummy bumps 51e are arranged in a straight line (FIG. 9). There is also an advantage that the stopping function is improved.

  In the above-described embodiment (FIGS. 2 to 4), the bump (second second) for conduction with the common electrode 43 is provided in a region of the diaphragm 30 facing the partition wall portion 20a that separates the two pressure chamber rows. Although the common electrode bump 51d) is bonded, as described above, if the purpose is only to prevent the warpage of the diaphragm 30, this bump does not need to be a bump for electrode conduction, and is a dummy bump. It may be.

3] In the above embodiment, as shown in FIG. 3, one piezoelectric body 40 is disposed across the plurality of pressure chambers 24, so that a plurality of piezoelectric elements 41 respectively corresponding to the plurality of pressure chambers 24 are integrated. It was a structured. On the other hand, as shown in FIG. 12, the plurality of piezoelectric elements 41 may be separated from each other and arranged at the center of the plurality of pressure chambers 24.

4] As understood from FIGS. 2 and 3 of the above-described embodiment, in order for the plurality of piezoelectric elements 41 to be covered by the driver IC 46, the size of the driver IC 46 is larger than the arrangement region of the plurality of piezoelectric elements 41. It is necessary to have a flat area. In other words, the maximum number of piezoelectric elements 41 (that is, the maximum number of nozzles 16) included in one head is restricted by the size of the driver IC 46. However, this does not mean that it is difficult to realize an ink jet head having a large number of nozzles 16 by applying the present invention. That is, by combining a plurality of head units as shown in FIGS. 2 and 3, an ink jet head having more nozzles 16 can be easily realized.

5] In the above-described embodiment, the driver IC 46 is provided with the plurality of bumps 51 for connecting the driver IC 46 and the plurality of connection terminals 50. However, the plurality of bumps 51 are connected to the plurality of connections on the flow path unit 20 side. The terminal 50 may be formed so as to protrude upward (driver IC 46 side).

  The above-described embodiment and its modifications are examples in which the present invention is applied to an ink jet head that is a liquid ejecting apparatus. However, the piezoelectric actuator of the present invention is used for applications that apply pressure to a liquid. Not limited. A plurality of piezoelectric elements are arranged on the substrate, and a plurality of piezoelectric elements are driven by a driver IC to deform the substrate, thereby causing displacement, vibration, etc. in a plurality of solid driving objects, respectively. You may use for an application.

4 Inkjet head 16 Nozzle 20 Flow path unit 20a Bulkhead portion 21 Piezoelectric actuator 24 Pressure chamber 30 Diaphragm 40 Piezoelectric body 41 Piezoelectric element 42 Drive electrode 43 Common electrode 43b First connection portion 43c Second connection portion 45 Drive terminal 46 Driver IC
47 Input terminal 50 Connection terminal 51a Drive bump 51b First common electrode bump 51c Input bump 51d First common electrode bump 51e Dummy bump 52 Sealing material

Claims (3)

A flow channel structure in which a liquid flow channel including a plurality of nozzles and a plurality of pressure chambers respectively communicating with the plurality of nozzles is formed;
A plurality of piezoelectric elements disposed on one surface of the flow path structure so as to face the plurality of pressure chambers,
A driver IC for driving the plurality of piezoelectric elements,
A plurality of connection terminals including a plurality of drive terminals respectively connected to the plurality of piezoelectric elements are arranged on a region around the plurality of piezoelectric elements on the one surface of the flow path structure.
The driver IC is disposed to face the one surface of the flow path structure so as to cover the plurality of piezoelectric elements,
A plurality of bumps protruding to the other side of the driver IC and the flow path structure are provided,
The plurality of first bumps included in the plurality of bumps connect the driver IC and the plurality of connection terminals arranged in the peripheral region of the plurality of piezoelectric elements, so that the plurality of piezoelectric elements are Surrounded by the plurality of first bumps;
An insulating sealing material is filled between the plurality of first bumps,
The plurality of pressure chambers are arranged in a predetermined direction along the one surface of the flow path structure,
The driver IC has a rectangular planar shape, and a long side thereof is arranged facing the one surface of the flow path structure in a state along the predetermined direction,
The plurality of driving terminals are arranged in a region along the long side of the driver IC in the peripheral region of the plurality of piezoelectric elements on the one surface of the flow path structure,
The connection terminals other than the drive terminals are arranged in a region along the short side of the driver IC in the peripheral region of the plurality of piezoelectric elements on the one surface of the flow path structure. A liquid ejecting apparatus. A flow channel structure in which a liquid flow channel including a plurality of nozzles and a plurality of pressure chambers respectively communicating with the plurality of nozzles is formed;
A plurality of piezoelectric elements disposed on one surface of the flow path structure so as to face the plurality of pressure chambers,
A driver IC for driving the plurality of piezoelectric elements,
A plurality of connection terminals including a plurality of drive terminals respectively connected to the plurality of piezoelectric elements are arranged on a region around the plurality of piezoelectric elements on the one surface of the flow path structure.
The driver IC is disposed to face the one surface of the flow path structure so as to cover the plurality of piezoelectric elements,
A plurality of bumps protruding to the other side of the driver IC and the flow path structure are provided,
The plurality of first bumps included in the plurality of bumps connect the driver IC and the plurality of connection terminals arranged in the peripheral region of the plurality of piezoelectric elements, so that the plurality of piezoelectric elements are Surrounded by the plurality of first bumps;
An insulating sealing material is filled between the plurality of first bumps,
The plurality of bumps further includes a second bump disposed between the plurality of first bumps,
The second bump is bonded to a region of the one surface of the flow channel structure where the connection terminal is not disposed,
The liquid ejecting apparatus, wherein the sealing material is filled between the first bump and the second bump. A flow channel structure in which a liquid flow channel including a plurality of nozzles and a plurality of pressure chambers respectively communicating with the plurality of nozzles is formed;
A plurality of piezoelectric elements disposed on one surface of the flow path structure so as to face the plurality of pressure chambers,
A driver IC for driving the plurality of piezoelectric elements,
A plurality of connection terminals including a plurality of drive terminals respectively connected to the plurality of piezoelectric elements are arranged on a region around the plurality of piezoelectric elements on the one surface of the flow path structure.
The driver IC is disposed to face the one surface of the flow path structure so as to cover the plurality of piezoelectric elements,
A plurality of bumps protruding to the other side of the driver IC and the flow path structure are provided,
The plurality of first bumps included in the plurality of bumps are provided along the entire periphery of the edge of the driver IC, and the plurality of first bumps cause the driver IC and the plurality of piezoelectric elements to be in the peripheral region. By connecting the plurality of connection terminals arranged, the plurality of piezoelectric elements are surrounded by the plurality of first bumps,
A liquid ejecting apparatus, wherein an insulating sealing material is filled between the plurality of first bumps.