JP6375973B2 - Liquid ejection device and method of manufacturing liquid ejection device - Google Patents

Description

  The present invention relates to a liquid ejection device that ejects liquid and a method of manufacturing the liquid ejection device.

  Patent Document 1 discloses an ink jet head that ejects ink onto a recording medium as a liquid ejecting apparatus. The inkjet head includes a flow path structure (flow path unit), a piezoelectric actuator provided in the flow path structure, and a wiring member (FPC) connected to the piezoelectric actuator.

  The channel structure is a laminate of a plurality of metal plates each having a channel hole. By laminating a plurality of metal plates and communicating the respective flow path holes, the flow path structure includes a plurality of nozzles and a plurality of pressure chambers respectively communicating with the plurality of nozzles. A road is formed.

  The piezoelectric actuator includes a piezoelectric layer, a plurality of individual electrodes arranged corresponding to the plurality of pressure chambers on the upper surface of the piezoelectric layer, and a plurality of individual electrodes sandwiched between the plurality of individual electrodes and the piezoelectric layer. And an opposing common electrode. In addition, a surface electrode that conducts to the common electrode is provided on the upper surface of the piezoelectric layer. The wiring member is joined to the piezoelectric actuator with the piezoelectric actuator covered from above. The plurality of individual electrodes of the piezoelectric actuator are respectively connected to a plurality of individual wires formed on the wiring member. The surface electrode is connected to the ground of the wiring member.

  Further, the surface electrode of the piezoelectric actuator is arranged so as to slightly protrude from the wiring member in the surface direction of the wiring member. A conductive material is disposed from the portion of the surface electrode protruding from the wiring member to the metal plate constituting the flow channel structure, and the surface electrode and the metal plate of the flow channel structure are electrically connected. As a result, the flow path structure including a plurality of metal plates is connected to the ground of the wiring member via the surface electrode, so that the potential of the flow path structure is maintained at the ground potential.

Japanese Patent Laying-Open No. 2006-15558 (FIG. 7)

  In order to make the flow path structure conductive with the surface electrode of the piezoelectric actuator, it is necessary to expose the surface electrode from the wiring member. Therefore, in Patent Document 1, a part of the piezoelectric actuator protrudes from the wiring member. This increases the planar size of the piezoelectric actuator.

  An object of the present invention is to make a metal portion of a flow channel structure conductive with a conductive portion of an actuator covered with a wiring member without increasing the planar size of the actuator.

The liquid ejection device of the present invention includes a flow path structure having a metal portion and a liquid flow path including a plurality of nozzles, and disposed on one surface of the flow path structure, An actuator that applies discharge energy to the liquid, and a wiring member that is disposed so as to cover the actuator and is electrically connected to the actuator,
The wiring member has a first conductive portion to which a predetermined reference potential is applied on a surface facing the actuator, and the actuator is electrically connected to the first conductive portion on a surface facing the wiring member. An opening is formed in a portion of the wiring member that covers the second conductive portion of the actuator, the first conductive portion being exposed from the wiring member in the opening. And the metal portion of the flow channel structure are electrically connected by a conductive portion made of a conductive material disposed across the actuator and the flow channel structure. .

1 is a schematic plan view of a printer 1 according to an embodiment. 2 is a plan view of the inkjet head 4. FIG. It is the A section enlarged view of FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. 2 is a plan view of a COF (Chip On Film) 51. FIG. It is a top view of 4 A of inkjet heads of a change form. It is an enlarged plan view equivalent to FIG. 3 of the inkjet head 4B of another modified form. It is a top view of inkjet head 4C of another modification. It is a top view of inkjet head 4D of another modification.

  Next, an embodiment of the present invention will be described. 1 is defined as the rear side of the printer 1 and the downstream side is defined as the front side of the printer 1. The scanning direction shown in FIG. 1 is defined as the left-right direction of the printer 1. Furthermore, a direction orthogonal to the scanning direction and the conveyance direction is defined as the up-down direction of the printer. In addition, the near side of FIG. 1 is an upper side, and the other side of FIG. 1 is a lower side. Below, it demonstrates using each direction word of front, back, left, right, up and down suitably.

(Schematic configuration of the printer)
As shown in FIG. 1, the inkjet printer 1 includes a platen 2, a carriage 3, an inkjet head 4, a cartridge holder 5, a transport mechanism 6, a control device 7, and the like.

  On the upper surface of the platen 2, a recording sheet 100 as a recording medium is placed. The carriage 3 is configured to be capable of reciprocating in the left-right direction (hereinafter also referred to as the scanning direction) along the two guide rails 11 and 12 in a region facing the platen 2. An endless belt 13 is connected to the carriage 3, and the endless belt 13 is driven by a carriage drive motor 14, whereby the carriage 3 moves in the scanning direction.

  The inkjet head 4 is mounted on the carriage 3 and can move in the scanning direction together with the carriage 3. The inkjet head 4 includes a plurality of nozzles 25 (see FIGS. 2 to 4) on the lower surface (the surface on the opposite side of the paper surface in FIG. 1).

  Four cartridges (black, yellow, cyan, and magenta) of ink cartridges 15 are detachably mounted on the cartridge holder 5. The cartridge holder 5 is connected to the inkjet head 4 by a tube (not shown). The four color inks respectively stored in the four ink cartridges 15 of the cartridge holder 5 are supplied to the inkjet head 4 through the tubes. The ink jet head 4 ejects ink toward the recording paper 100 placed on the platen 2 from the plurality of nozzles 25 formed on the lower surface thereof while moving in the scanning direction. The detailed configuration of the inkjet head 4 will be described later.

  The transport mechanism 6 has two transport rollers 16 and 17 arranged so as to sandwich the platen 2 in the front-rear direction. The two transport rollers 16 and 17 are driven in synchronization with each other by a transport motor (not shown). The transport mechanism 6 transports the recording paper 100 placed on the platen 2 forward (hereinafter also referred to as a transport direction) by two transport rollers 16 and 17.

  The control device 7 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an ASIC (Application Specific Integrated Circuit) including various control circuits, and the like. The control device 7 causes the ASIC to execute various processes such as a printing process on the recording paper 100 by executing a program stored in the ROM by the CPU. For example, in the printing process, the control device 7 controls the inkjet head 4, the carriage drive motor 14, the transport motor of the transport mechanism 6, and the like based on a print command input from an external device such as a PC, thereby recording paper An image or the like is printed on 100. More specifically, an ink discharge operation for discharging ink while moving the inkjet head 4 together with the carriage 3 in the scanning direction, and a transport operation for transporting the recording paper 100 by a predetermined amount in the transport direction by the transport rollers 16 and 17, Let it happen alternately.

(Detailed configuration of inkjet head)
Next, the inkjet head 4 will be described. In FIG. 2, for simplicity of the drawing, the COF 51 that is electrically connected to the piezoelectric actuator 21 and the conductive portion that is disposed on the piezoelectric actuator 21 are clearly shown in FIGS. 3 and 4. 56 is schematically indicated by a two-dot chain line. As shown in FIGS. 2 to 4, the inkjet head 4 includes a flow path structure 20, a piezoelectric actuator 21 disposed on the upper surface of the flow path structure 20, and a flow path structure so as to cover the piezoelectric actuator 21. 20 is provided with a COF 51 disposed above 20.

(Flow path unit)
As shown in FIG. 4, the flow channel structure 20 is formed by stacking five plates 31 to 35 each having a flow channel formation hole. Of the five plates 31 to 35, the lowermost plate 35 is a nozzle plate in which a plurality of nozzles 25 are formed. The nozzle plate 35 is a plate formed of a synthetic resin material such as polyimide. On the other hand, the remaining four plates 31 to 34 on the upper side are formed with channel holes serving as ink channels such as the manifold 24 and the pressure chamber 26 communicating with the plurality of nozzles 25. Each of the four plates 31 to 34 is a plate formed of a metal material. When these five plates 31 to 35 are stacked, the respective flow path holes communicate with each other, whereby an ink flow path as described below is formed in the flow path structure 20.

  As shown in FIG. 2, four ink supply holes 23 connected to the four ink cartridges 15 (see FIG. 1) are formed on the upper surface of the flow path structure 20. Four manifolds 24 connected to the four ink supply holes 23 are formed in the flow path structure 20. Four inks of four ink cartridges 17 are supplied to the four manifolds 24 through the four ink supply holes 23, respectively. The four manifolds 24 extend in the transport direction.

  The flow path structure 20 includes a plurality of nozzles 25 formed on the lowermost nozzle plate 35 and a plurality of pressure chambers 26 formed on the uppermost plate 31. As shown in FIG. 2, a plurality of nozzles 25 are arranged along the transport direction on the lower surface of the flow path structure 20 (the surface on the opposite side of FIG. 3), and scans corresponding to the four manifolds 24. Four nozzle rows are arranged in the direction. The transport direction, which is the direction in which the plurality of nozzles 25 are arranged, corresponds to the “first direction” of the present invention. The scanning direction in which the four nozzle rows are arranged corresponds to the “second direction” of the present invention.

  The plurality of pressure chambers 26 are arranged in four rows corresponding to the four manifolds 24 and the four nozzle rows in the central portion of the upper surface of the flow path structure 20. Each pressure chamber 26 has a substantially elliptical planar shape that is long in the scanning direction. As shown in FIGS. 3 and 4, one end in the longitudinal direction of each pressure chamber 26 communicates with the manifold 24, and the other end in the longitudinal direction communicates with the nozzle 25. As a result, as shown in FIG. 4, the flow channel structure 20 is formed with a plurality of individual flow channels that branch from the manifold 24 and reach the nozzles 25 through the pressure chambers 26. FIG. 4 shows a state where the ink I is filled in the individual flow paths such as the manifold 24 and the plurality of pressure chambers 26.

  As shown in FIG. 4, the uppermost plate 31 of the flow path structure 20 is electrically connected to a ground conductive portion 62 of a COF 51 described later by a conductive portion 56 made of a conductive material. As a result, the potentials of the four metal plates 31 to 34 of the flow path structure 20 are maintained at the ground potential, and the potential of the ink in the flow path structure 20 is also the ground potential.

(Piezoelectric actuator)
The piezoelectric actuator 21 applies ejection energy to the ink in each nozzle 25 of the flow path structure 20 and ejects ink from each nozzle 25. The piezoelectric actuator 21 is disposed on the upper surface of the flow path structure 20 so as to cover the plurality of pressure chambers 26. As shown in FIGS. 2 to 4, the piezoelectric actuator 21 includes an ink sealing film 40, two piezoelectric layers 41 and 42, a plurality of individual electrodes 44, and a common electrode 45.

  The ink sealing film 40 is a thin film formed of a material having low ink permeability, for example, a metal material such as stainless steel. The ink sealing film 40 is bonded to the upper surface of the flow path structure 20 so as to cover the plurality of pressure chambers 26.

  The two piezoelectric layers 41 and 42 are each made of a piezoelectric material. As a piezoelectric material constituting the piezoelectric layers 41 and 42, lead zirconate titanate which is a mixed crystal of lead titanate and lead zirconate can be employed. In addition, a lead-free piezoelectric material such as barium titanate or a niobium-based piezoelectric material may be employed. The piezoelectric layers 41 and 42 are bonded to the upper surface of the ink sealing film 40 while being stacked on each other.

  The plurality of individual electrodes 44 are disposed on the upper surface of the upper piezoelectric layer 41. More specifically, as shown in FIGS. 2 to 4, each individual electrode 44 has a shape that is long in the scanning direction according to the shape of the pressure chamber 26. In addition, each individual electrode 44 is disposed in a region on the upper surface of the piezoelectric layer 41 that faces the central portion of the pressure chamber 26. The plurality of individual electrodes 44 are arranged along the transport direction so as to correspond to the plurality of pressure chambers 26 and constitute four individual electrode rows.

  Each individual electrode 44 has a terminal portion 46 disposed in a region not facing the pressure chamber 26 at one end portion (right end portion) in the scanning direction. As shown in FIG. 4, each of the terminal portions 46 of the plurality of individual electrodes 44 is joined to an individual terminal 61 of a COF 51 described later and a joint portion 48 made of a conductive adhesive. The conductive adhesive is an adhesive made by mixing metal particles with a thermosetting resin and capable of joining two members to be joined in an electrically conductive state. .

  As will be described later, as shown in FIG. 2, a driver IC 53 is mounted on the COF 51, and the driver IC 53 is connected to a plurality of individual terminals 61 of the COF 51. The COF 51 is also electrically connected to the control device 7 (see FIG. 1). The driver IC 53 selectively applies either one of the drive potential and the ground potential to each individual electrode 44 based on the control signal input from the control device 7.

  The common electrode 45 is continuously disposed across the plurality of individual electrodes 44 between the two piezoelectric layers 41 and 42. As a result, the common electrode 45 faces the plurality of individual electrodes 44 in common across the piezoelectric layer 41.

  As shown in FIG. 2, two surface electrodes 47 extending in the transport direction are provided on the upper surfaces of both end portions (left and right end portions) in the scanning direction of the upper piezoelectric layer 41. That is, the two surface electrodes 47 are arranged on the outer side (both left and right sides) in the scanning direction with respect to the plurality of individual electrodes 44. The scanning direction in which the plurality of individual electrodes 44 and the surface electrode 47 are adjacent corresponds to the “third direction” of the present invention. In other words, the present embodiment is a form in which the second direction and the third direction of the present invention match. In addition, a plurality of through holes 41a penetrating the piezoelectric layer 41 are formed in a portion of the upper piezoelectric layer 41 where the surface electrode 47 is formed, and each through hole 41a is filled with a conductive material. Yes. The two surface electrodes 47 arranged on the upper surface of the piezoelectric layer 41 are electrically connected to the common electrode 45 located between the two piezoelectric layers 41 and 42 through the conductive material in the plurality of through holes 41a. doing.

  Each surface electrode 47 is electrically connected to a ground conductive portion 62 of COF 51 described later by a joint portion 49 made of a conductive adhesive. As a result, the common electrode 45 is connected to the ground via the surface electrode 47, the joint portion 49, and the ground conductive portion 62 of the COF 51, and the potential of the common electrode 45 is always maintained at the ground potential (reference potential). ing.

  A portion of the piezoelectric layer 41 sandwiched between the individual electrode 44 and the common electrode 45 is particularly referred to as an active portion 43. The active portion 43 is polarized downward in the thickness direction, that is, in a direction from the individual electrode 44 toward the common electrode 45.

  The operation of the piezoelectric actuator 21 described above when ejecting ink from the nozzle 25 is as follows. It is assumed that the potential of a certain individual electrode 44 is switched from the ground potential to the drive potential by the driver IC 53. At this time, a potential difference is generated between the individual electrode 44 to which the drive potential is applied and the common electrode 45 maintained at the ground potential. As a result, an electric field in the thickness direction is generated in the active portion 43 of the piezoelectric layer 41. Further, since the polarization direction of the active portion 43 and the direction of the electric field coincide with each other, the active portion 43 extends in the thickness direction, which is the polarization direction, and contracts in the plane direction. As the active portion 43 contracts and deforms, the two piezoelectric layers 41 and 42 are bent so as to protrude toward the pressure chamber 26. As a result, the volume of the pressure chamber 26 is reduced, pressure is applied to the ink therein, and ink droplets are ejected from the nozzles 25 communicating with the pressure chamber 26.

(COF)
Next, the configuration of the COF 51 will be described. The COF 51 is electrically connected to the control device 7 (see FIG. 1) and the piezoelectric actuator 21, respectively. As shown in FIGS. 4 and 5, the COF 51 includes a flexible substrate 52 formed of a synthetic resin material such as polyimide, and two driver ICs 53 mounted on the substrate 52.

  As shown in FIG. 2, the substrate 52 has a long shape in the transport direction, and is disposed above the flow path structure 20 so as to cover the piezoelectric actuator 21. A portion of the substrate 52 that covers the piezoelectric actuator 21 is joined to the piezoelectric actuator 21. Further, the substrate 52 extends from the piezoelectric actuator 21 to both sides in the transport direction, and both end portions in the transport direction are bent upward (front side in FIG. 2), and then the control device 7. Connected.

  A plurality of individual terminals 61 respectively corresponding to the plurality of individual electrodes 44 of the piezoelectric actuator 21 are disposed on the lower surface of the central portion of the portion of the substrate 52 facing the piezoelectric actuator 21. On the lower surface of both ends in the scanning direction of the portion of the substrate 52 that faces the piezoelectric actuator 21, ground conductive portions 62 that extend along the transport direction are formed. Each ground conductive portion 62 includes a conductive portion 62a extending in the transport direction so as to face the surface electrode 47 of the piezoelectric actuator 21, and two wiring portions 62b extending forward and backward from the conductive portion 62a. The wiring part 62 b of each ground conductive part 62 is connected to the ground via the control device 7.

  As shown in FIG. 5, the two driver ICs 53 are arranged on the front portion and the rear portion of the substrate 52 with respect to the plurality of individual terminals 61, respectively. Each driver IC 53 is connected to the control device 7 by a plurality of input wirings 63 formed on the substrate 52. The driver IC 53 is connected to a plurality of individual terminals 61 by a plurality of output wirings 64 formed on the substrate 52.

  As shown in FIG. 4, a coating material 66 made of an insulating film or the like is provided on the lower surface of the substrate 52. The covering material 66 covers the plurality of input wires 63, the plurality of output wires 64, and the wiring portions 62 b of the two ground conductive portions 62 formed on the substrate 52. On the other hand, the plurality of individual terminals 61 and the conductive portions 62a of the two ground conductive portions 62 that are electrically connected to the piezoelectric actuator 21 are not covered with the covering material 66 but are exposed. The plurality of individual terminals 61 are electrically connected to the terminal portions 46 of the plurality of individual electrodes 44 by joint portions 48 made of a conductive adhesive. The conducting portion 62a of the ground conductive portion 62 is electrically connected to the surface electrode 47 of the piezoelectric actuator 21 by a joint portion 49 made of a conductive adhesive.

  As shown in FIGS. 2 to 4, an opening 55 having a shape cut out from the left edge is formed in the left end of the substrate 52 covering the surface electrode 47 of the piezoelectric actuator 21. ing. The opening 55 is a notch having a rectangular planar shape. The conductive portion 62a of the ground conductive portion 62 that faces the surface electrode 47 is disposed at the left end portion of the substrate 52. The opening 55 is a central portion of the substrate 52 in the transport direction of the conductive portion 62a. Is formed in the portion where the is disposed. Due to the opening 55, a part of the surface electrode 47 covered with the COF 51 is exposed from the COF 51. The size of the opening 55 is, for example, 5 mm × 10 mm. The surface electrode 47 is formed 5 mm away from the left end of the substrate 52. The width of the surface electrode 47 in the left-right direction is, for example, 3 mm.

  Further, the opening 55 is formed in an outer portion in the scanning direction, that is, a portion on the surface electrode 47 side of the substrate 52 of the COF 51 with respect to the portion covering the plurality of individual electrodes 44. That is, the plurality of individual electrodes 44 are all covered with the substrate 52, and the individual electrodes 44 are not exposed from the opening 55.

  Furthermore, at the position of the left end portion of the COF 51, a conduction portion 56 made of a conductive material is disposed across the flow path structure 20 and the piezoelectric actuator 21. The area of the conduction part 56 when viewed from above is larger than the area of the opening 55, and the conduction part 56 covers the entire area of the opening 55 of the COF 51. In addition, as a conductive material constituting the conductive portion 56, a conductive paste having fluidity obtained by dispersing metal particles such as silver in a thermosetting resin material can be suitably used.

  A part of the surface electrode 47 exposed from the COF 51 in the opening 55 and the metal plate 31 of the flow path structure 20 are electrically connected by the conductive portion 56. As a result, the plate 31 of the flow channel structure 20 is electrically connected to the ground conductive portion 62 of the COF 51 via the conductive portion 56 and the surface electrode 47 of the piezoelectric actuator 21. A ground potential is applied to 31-34. By maintaining the metal plates 31 to 34 in which the ink flow paths such as the pressure chambers 26 are formed at the ground potential, the potential of the ink in the ink flow path also becomes the ground potential. As a result, charging of the ink is suppressed, and ejection bending due to charging of the ink is prevented.

  A schematic manufacturing process of the inkjet head 4 will be described. First, after the flow path structure 20 including the five plates 31 to 35 is manufactured, the piezoelectric actuator 21 including the piezoelectric layer 42 is formed on the upper surface of the flow path structure 20. Further, the COF 51 in which the opening 55 is formed is disposed above the flow path structure 20 so as to cover the piezoelectric actuator 21. Next, the plurality of individual terminals 61 of the COF 51 and the terminal portions 46 of the plurality of individual electrodes 44 of the piezoelectric actuator 21 are joined together with a conductive adhesive, and the conduction portion 62a of the ground conductive portion 62 of the COF 51 and the piezoelectric actuator 21 are connected. The surface electrode 47 is joined with a conductive adhesive. Furthermore, a conductive material such as a conductive paste is attached to the upper surface of the flow path structure 20 from the opening 55 of the COF 51 by a method such as screen printing. By the conducting portion 56 made of the conductive material, the surface electrode 47 exposed from the COF 51 in the opening 55 and the plate 31 of the flow path structure 20 are conducted. In addition, the conduction | electrical_connection part 56 is comprised with a wire, and the flow-path structure 20 and the surface electrode 47 may be conduct | electrically_connected by wire bonding.

  As described above, in this embodiment, a part of the surface electrode 47 of the piezoelectric actuator 21 is exposed from the COF 51 through the opening 55 formed in the substrate of the COF 51. Further, the plate 31 of the flow path structure 20 and the surface electrode 47 of the piezoelectric actuator 21 are electrically connected by the conductive portion 56 made of a conductive material disposed across the flow path structure 20 and the piezoelectric actuator 21. . According to this configuration, since the surface electrode 47 of the piezoelectric actuator 21 is electrically connected to the plate 31 of the flow path structure 20, it is not necessary to protrude a part of the conductive portion from the COF 51. do not do.

  Although the shape of the opening 55 of the COF 51 is not particularly limited, in the present embodiment, the opening 55 has a rectangular cutout shape. In the case where the opening 55 has a hole shape with edges around the entire circumference, a part of the substrate 52 made of an insulating material exists between the opening 55 and the flow path structure 20. Become. In this case, it is necessary to provide a conducting portion 56 for conducting the surface electrode 47 of the piezoelectric actuator 21 and the plate 31 of the flow path structure 20 so as to straddle the insulating substrate 52. On the other hand, when the opening 55 has a shape cut out from the left side, the opening 55 has no left edge. Accordingly, since the insulating substrate 52 of the COF 51 does not exist between the surface electrode 47 and the plate 31 of the flow path structure 20, the conduction reliability between the surface electrode 47 and the flow path structure 20 by the conduction portion 56 is present. Increases nature.

  The ground conductive portion 62 of the COF 51 includes a conductive portion 62a that is electrically connected to the surface electrode 47 of the piezoelectric actuator 21, and two wiring portions 62b that extend forward (downstream in the transport direction) and backward (upstream in the transport direction) from the conductive portion 62a. And have. As a result, a ground potential is applied to the surface electrode 47 of the piezoelectric actuator 21 from the front and rear directions. In this configuration, an opening 55 is formed in a portion of the COF 51 where the central portion in the transport direction of the conductive portion 62a of the ground conductive portion 62 is disposed. That is, the opening 55 is formed at the terminal position where the ground potential application paths from the two directions in the transport direction join the surface electrode 47.

  Therefore, even when potential variation occurs between the paths from the two directions, the potential of the flow channel structure 20 that is electrically connected to the surface electrode 47 exposed from the opening 55 is averaged. Is unlikely to occur. Also, as shown in FIG. 3, the opening 55 is formed at the left end of the substrate 52 of the COF 51 in the scanning direction, so that the conduction portion 62a of the ground conductive portion 62 disposed at the left end is also forward and backward. It is divided. If the width of the conductive portion 62a of the ground conductive portion 62 is increased, the conductive portion 62a can be prevented from being divided by the opening 55, but the width of the conductive portion 62a is still reduced. If there is a divided portion or a small width portion in the middle portion of the ground conductive portion 62, there arises a problem that the electrical resistance of the ground conductive portion 62 increases and the conduction reliability is lowered. However, in the present embodiment, since the opening 55 is located at the terminal position of the ground potential application path to the surface electrode 47 of the ground conductive part 62, a part of the ground conductive part 62 is divided by the opening 55. Even if the width is narrowed, no major problem occurs in terms of an increase in electrical resistance and a decrease in conduction reliability.

  In the present embodiment, two ground conductive portions 62 are formed at the left and right end portions of the COF 51. However, the opening 55 is formed only at the left end of the COF 51, and the opening 55 is not formed at the right end. The reason is as follows.

  Each individual electrode 44 has a terminal portion 46 at one end (right end) in the scanning direction, and the individual electrode 44 is joined to the individual terminal 61 of the COF 51 in this terminal portion 46. In this configuration, when the opening 55 is formed also at the right end of the COF 51 and the conduction portion 56 made of a conductive material is provided in the opening 55, the terminal portion 46 of the individual electrode 44 and the opening 55 are provided. The distance becomes closer. Therefore, when the terminal part 46 of the individual electrode 44 and the individual terminal 61 of the COF 51 are joined with a conductive adhesive, the conductive adhesive flows to the opening 55 and the individual electrode 44 and the conduction part 56 are conducted. It is possible. Therefore, in the present embodiment, the opening 55 is formed only at the left end of the COF 51, and only the left surface electrode 47 is exposed from the opening 55. At the left end portion of the COF 51, the distance between the terminal portion 46 of the individual electrode 44 and the opening 55 is increased, so that the problem that the individual electrode 44 and the conducting portion 56 are conducted is less likely to occur.

  As shown in FIGS. 2 and 3, the opening 55 is formed on the left side (surface electrode 47 side) of the COF 51 with respect to the portion covering the plurality of individual electrodes 44. In this configuration, since the individual electrode 44 is not exposed from the opening 55, when the conductive portion 56 made of a conductive material is disposed on the surface electrode 47 exposed from the opening 55, the individual electrode 44 and the conductive portion are arranged. 56 is prevented from conducting.

  As shown in FIG. 3, in this embodiment, since the conducting portion 56 is disposed so as to cover the entire area of the opening 55, the surface electrode 47 exposed from the opening 55 and the opening 55 are disposed. Therefore, the conduction reliability between the flow path structure 20 and the surface electrode 47 is increased.

  In the embodiment described above, the ink jet head corresponds to the “liquid ejecting apparatus” of the invention. The metal plate of the flow path structure 20 corresponds to the “metal part” of the present invention. The COF 51 corresponds to the “wiring member” of the present invention. The ground conductive portion 62 of the COF 51 corresponds to the “first conductive portion” of the present invention. The surface electrode 47 of the piezoelectric actuator 21 corresponds to the “second conductive portion” of the present invention.

  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] In the above embodiment, the opening 55 is formed only at one end in the scanning direction of the COF 51. However, the openings 55 and 67 are formed at the left and right ends of the COF 70, respectively, as in the inkjet head 4A shown in FIG. And the conductive portions 56 and 68 may be provided in the openings 55 and 67, respectively.

2] The shape of the opening of the COF 51 is not limited to that of the above embodiment. For example, a notch shape other than a rectangular shape such as a trapezoidal shape or a triangular shape may be used. Or the shape of the opening part 72 of COF71 may be a hole shape in which an edge exists over the perimeter like the inkjet head 4B shown in FIG.

3] The COF 51 of the above-described embodiment has two driver ICs 53 that extend from the piezoelectric actuator 21 to both sides in the transport direction and are arranged at the front and rear. On the other hand, like the inkjet head 4C in FIG. 8, the COF 73 may have only one driver IC 53 and extend from the piezoelectric actuator 21 only to one side in the transport direction.

  In the configuration of FIG. 8, the ground conductive portion 74 of the COF 73 includes a conductive portion 74 a that conducts with the surface electrode 47 of the piezoelectric actuator 21, and a wiring portion that extends from the conductive portion 74 a to one side (forward in the drawing) in the transport direction. 74b. That is, in this configuration, unlike FIG. 2 of the embodiment, the ground potential is applied to the surface electrode 47 only from one side in the transport direction. In this case, in the portion of the COF 73 where the opening 77 is formed, the conducting portion 74a of the ground conductive portion 74 may be divided or the width may be narrowed. Therefore, as shown in FIG. 8, an opening 77 is formed in the portion where the other end portion (rear end portion in FIG. 8) of the COF 73 in the transport direction of the conductive portion 74 a of the ground conductive portion 74 is disposed. A conducting portion 78 is provided on the opening 77. In this configuration, an opening 77 is formed at the end position of a path for applying a ground potential from the ground conductive portion 74 to the surface electrode 47. Therefore, even if the conductive portion 74a is divided by the formation of the opening 77 or the width is narrowed, no serious problem occurs.

  Further, the COF is not limited to the form extending from the piezoelectric actuator in the transport direction, and the COF may extend in the scanning direction. In this case, a ground conductive part is preferably arranged at the end of the COF in the transport direction.

4] Like the inkjet head 4D of FIG. 9, the ground conductive portion 76 of the COF 75 may be disposed only at a part of the end of the substrate 52 of the COF 75 in the scanning direction. In this case, the opening 55 of the COF 75 may be formed in a portion of the end portion of the substrate 52 where the ground conductive portion 76 is not disposed. Specifically, in FIG. 9, the ground conductive portion 76 is not disposed at the central portion in the front-rear direction of the portion facing the piezoelectric actuator 21 of the substrate 52, and is disposed only at the front end portion and the rear end portion. ing. Further, the opening 55 of the COF 75 is disposed at a central portion in the front-rear direction where the ground conductive portion 76 is not formed, at a portion facing the piezoelectric actuator 21 of the substrate 52. As described above, the ground conductive portion 76 is arranged only in a part in the front-rear direction, so that the amount of conductive paste necessary for forming the ground conductive portion 76 can be reduced, and the cost can be reduced. be able to.

5] In the above embodiment, the entire upper surface of the flow path structure 20 is formed of the metal plate 31, but only a partial region of the upper surface of the flow path structure 20 may be formed of metal. . Or the structure by which the upper surface of the flow-path structure 20 was coat | covered with the insulating material except the one part area | region may be sufficient.

6] In the above embodiment, as shown in FIG. 3, the conducting portion 56 covers the entire area of the opening 55 of the COF 51. On the other hand, the conduction part 56 only needs to be in contact with at least a part of the surface electrode 47 exposed from the opening 55, and does not necessarily need to cover the entire area of the opening 55.

7] In the above embodiment, the ground conductive portion 62 of the COF 51 is disposed so as to pass beside the driver IC 53. However, the ground conductive portion 62 is connected to the ground portion in the driver IC 53, and the driver IC 53 is interposed therebetween. Thus, a ground potential may be applied to the ground conductive portion 62.

8] The above embodiment is an example in which a piezoelectric actuator is employed as an actuator for applying ejection energy to the ink in the nozzle. However, the present invention is also applied to a configuration in which an actuator other than the piezoelectric actuator is employed. It is possible. For example, the actuator may include a heating substrate having a heating element that applies thermal energy to ink, and ink may be ejected from the nozzles using ink film boiling. That is, the wiring member is disposed so as to cover the conductive portion on the surface of the heating substrate, and the conductive portion exposed from the wiring member in the opening and the metal portion of the flow path unit are formed by the conductive portion disposed in the opening. The structure which conduct | electrically_connects may be sufficient.

  The embodiments described above and the modifications thereof are applied to an ink jet printer that prints an image or the like by ejecting ink onto a recording sheet, but can be used for various purposes other than printing an image or the like. The present invention can also be applied to a liquid ejecting apparatus. For example, the present invention can also be applied to an industrial liquid discharge apparatus that discharges a conductive liquid onto a substrate to form a conductive pattern on the substrate surface.

4 Inkjet head 20 Flow path structure 21 Piezoelectric actuator 25 Nozzle 26 Pressure chamber 31 Plate 44 Individual electrode 45 Common electrode 46 Terminal portion 47 Surface electrode 51 COF
52 substrate 55 opening 56 conducting portion 62 ground conducting portion 62a conducting portion 62b wiring portion 67 opening 68 conducting portion 72 opening 74 ground conducting portion 74a conducting portion 74b wiring portion 76 ground conducting portion 77 opening 78 conducting portion

Claims (9)

A channel structure having a liquid channel including a metal portion and including a plurality of nozzles;
An actuator that is disposed on one surface of the flow path structure and applies discharge energy to the liquid in the plurality of nozzles;
A wiring member arranged to cover the actuator and electrically connected to the actuator,
The wiring member has a first conductive portion to which a predetermined reference potential is applied on a surface facing the actuator,
The actuator has a second conductive portion that is electrically connected to the first conductive portion on a surface facing the wiring member,
An opening is formed in a portion of the wiring member that covers the second conductive portion of the actuator,
A conductive material in which a part of the second conductive portion exposed from the wiring member in the opening and the metal portion of the flow channel structure are disposed across the actuator and the flow channel structure A liquid ejecting apparatus, wherein the liquid ejecting apparatus is conducted by a conducting part.   The liquid ejection device according to claim 1, wherein the opening is formed in a shape cut out from an edge of the wiring member. The actuator includes a plurality of individual electrodes provided corresponding to the plurality of nozzles and arranged along a first direction on a surface facing the wiring member,
The second conductive portion is disposed outside in the second direction orthogonal to the first direction with respect to the plurality of individual electrodes, and extends along the first direction,
The wiring member extends from the actuator to both sides in the first direction,
The first conductive portion of the wiring member is
A conductive portion disposed along the first direction, facing the second conductive portion and conducting with the second conductive portion, and two wiring portions extending from the conductive portion to both sides in the first direction, respectively. And
The opening is formed in a portion of the wiring member where a central portion in the first direction of the conductive portion of the first conductive portion is disposed. Liquid discharge device. The actuator includes a plurality of individual electrodes provided corresponding to the plurality of nozzles and arranged along a first direction on a surface facing the wiring member,
The second conductive portion is disposed outside in the second direction orthogonal to the first direction with respect to the plurality of individual electrodes, and extends along the first direction,
The wiring member extends only from the actuator to one side in the first direction,
The first conductive portion of the wiring member is
A conductive portion disposed along the first direction and facing the second conductive portion and conducting with the second conductive portion; and a wiring portion extending from the conductive portion to the one side in the first direction. Have
The opening is formed in a portion of the wiring member where the other end portion in the first direction of the conductive portion of the first conductive portion is disposed. 3. The liquid ejection device according to 2. The actuator includes a plurality of individual electrodes provided corresponding to the plurality of nozzles and arranged along a first direction on a surface facing the wiring member,
Each individual electrode has a terminal portion joined to the wiring member at one end in a second direction orthogonal to the first direction,
The second conductive portion is disposed on the other end side in the second direction with respect to the plurality of individual electrodes,
The liquid ejection device according to claim 1, wherein the opening is formed in a portion of the wiring member that covers the second conductive portion. The actuator has a plurality of individual electrodes arranged corresponding to the plurality of nozzles on a surface facing the wiring member,
The second conductive portion and the plurality of individual electrodes are arranged side by side in a third direction parallel to the one surface of the flow path structure,
The wiring member covers the plurality of individual electrodes,
The opening of the wiring member is formed in a portion closer to the second conductive portion in the third direction than a portion covering the plurality of individual electrodes. The liquid ejection device according to any one of the above.   The liquid ejecting apparatus according to claim 1, wherein the conducting portion is disposed so as to cover the entire area of the opening of the wiring member.   The liquid ejection device according to claim 1, wherein the opening has a rectangular planar shape. A method for manufacturing a liquid ejection device according to claim 1,
The wiring member in which the opening is formed is disposed so as to cover the actuator, and the first conductive portion of the wiring member is electrically joined to the second conductive portion,
After joining the wiring member to the actuator, a conductive portion made of a conductive material is disposed from the opening of the wiring member to the metal portion of the flow channel structure, and the conductive portion A method of manufacturing a liquid ejection apparatus, wherein the second conductive portion exposed from the wiring member is electrically connected to the metal portion of the flow path structure.

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