JP2008213209A - Liquid ejection head and liquid ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejection head and a liquid ejector in which electrolysis of liquid resulting from adhesion of conductive foreign matter can be prevented. <P>SOLUTION: An insulating material 60 is bonded to the tip side part of an oscillator base material, and then the oscillator base material is divided into individual piezoelectric oscillators 15 thus forming an oscillator unit 16. Under a state where the oscillator unit is contained in the containing chamber 53 of a head case 18 and the distal end face of a free end portion 15a is butted against the surface at the island 49 of a diaphragm 47, the insulating material is interposed as an insulating portion 59 between the island 49 and the distal end face at the free end portion of the piezoelectric oscillators 15 thus insulating the island 49 and the piezoelectric oscillators 15 electrically. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head such as an ink jet recording head, and a liquid ejecting apparatus, and in particular, includes a flow path unit that forms a series of liquid flow paths from a common liquid chamber to a nozzle opening through a pressure chamber. The present invention relates to a liquid ejecting head capable of ejecting liquid as droplets from a nozzle opening by driving a pressure generating unit, and a liquid ejecting apparatus including the liquid ejecting head.

  Examples of liquid ejecting heads that discharge liquid droplets from nozzle openings by causing pressure fluctuations in the pressure chambers include, for example, ink jet recording heads used in image recording apparatuses such as printers, and manufacture of color filters such as liquid crystal displays. Material injection heads used in manufacturing, electrode material injection heads used for electrode formation of organic EL (Electro Luminescence) displays, FEDs (surface emitting displays), etc., and bioorganic matter injection heads used in the manufacture of biochips (biochemical elements) Etc.

  A recording head, which is a kind of liquid ejecting head, has a series of liquid flow paths from a common ink chamber (common liquid chamber / reservoir) to a nozzle through a pressure chamber, and operates pressure generating means such as a piezoelectric vibrator. Thus, a pressure fluctuation is generated in the liquid in the pressure chamber, and the ink in the pressure chamber can be ejected as an ink droplet from the nozzle using the pressure fluctuation. In this recording head, an actuator unit (vibrator unit) in which a piezoelectric vibrator group is joined to a fixed plate and a flow path unit in which the ink flow path is formed are fixed to a head case. There is.

  The flow path unit includes, for example, a metal plate-like nozzle plate in which a plurality of nozzle openings are opened in a row, a flow path forming substrate on which a flow path base portion serving as an ink flow path such as a pressure chamber is formed, A sealing plate (vibration plate) that seals the opening of the flow path base of the path forming substrate is provided, and these members are manufactured by integrating them in a laminated state. The sealing plate is made of a composite plate material in which a resin elastic film is laminated on a metal support plate such as stainless steel and the support plate is partially removed, and the surface on the elastic film side is a flow path forming substrate. It comes to be joined to. A portion of the sealing plate corresponding to the pressure chamber is provided with a diaphragm portion that changes the volume of the pressure chamber. This diaphragm part is manufactured by removing the supporting plate around the island part by etching or the like and leaving only the elastic film while leaving the part where the tip surface of the piezoelectric vibrator is joined as an island part. Yes. In addition, an ink introduction hole (liquid introduction hole) for introducing ink from the case flow path side of the head case into a common ink chamber that is a part of the ink flow path is provided in a portion corresponding to the common ink chamber in the sealing plate. However, it is established in a state where it penetrates the support plate and the elastic film.

  A head case is a member formed in the shape of a hollow block, for example with a synthetic resin. The head case is formed with a storage chamber in which the actuator unit can be stored. The housing chamber is formed in a series from the bottom surface of the head case serving as the flow path unit joint surface to the upper surface opposite to the bottom surface. That is, the storage chamber is formed as a through opening that penetrates the height direction of the head case. Further, a case flow path is provided inside the head case so as to penetrate the height direction. The upper end of the case flow path communicates with the ink introduction path of the introduction needle unit including the ink introduction needle, and the lower end of the case flow path communicates with the ink flow path in the flow path unit through the ink introduction hole of the sealing plate. It is like that. Therefore, the ink introduced from the ink introduction needle is supplied to the ink channel side through the case channel and the ink introduction hole.

  A flow path unit is joined to the bottom surface of the head case having the above configuration. Specifically, the diaphragm portion of the sealing plate is disposed in the opening on the bottom side of the storage chamber, and the sealing plate is placed in a state where the case channel and the ink channel are in fluid-tight communication with each other through the ink introduction hole. The flow path unit is fixed to the head case by bonding to the bottom surface of the head case by bonding or the like. The actuator unit is inserted from the opening on the upper surface side of the accommodation chamber in a posture with the free end of the piezoelectric vibrator as the head, and is accommodated in the accommodation chamber in a state where the tip of the free end is in contact with the surface of the island portion. Is done. And while joining the front-end | tip of a free end part of a piezoelectric vibrator to an island part, an actuator unit is fixed in a storage chamber by adhere | attaching a fixed plate (fixed board | substrate) to the inner wall face of a storage chamber (patent document 1). reference).

JP 2000-006397 A (FIGS. 1 and 2)

  Here, since the island portion functioning as the diaphragm portion is electrically independent from the other portions of the support plate, normally, even if a drive signal is applied to the piezoelectric vibrator, current flows from the island portion to the other portions. Will not flow. However, since the diaphragm part is exposed from the bottom opening of the head case into the accommodation chamber, for example, foreign matters such as processing waste may enter the accommodation chamber during the assembly process of the recording head and fall to the diaphragm part. When the foreign matter has conductivity such as metal, there is a risk of short-circuiting between the diaphragm portion (that is, the island portion) and the other portion of the support plate. When such a short circuit occurs, the entire support plate is at the same potential (positive potential) as the individual electrode formed on the tip surface side of the piezoelectric vibrator. On the other hand, the nozzle plate disposed on the opposite side of the support plate from the flow path forming substrate is adjusted to the ground potential to prevent charging. As a result, the inner peripheral surface of the ink introduction port, which is a portion in contact with the ink on the support plate, and the peripheral portion of the nozzle opening of the nozzle plate act like an electrode so that the ink between them is electrolyzed. There is a fear. As the electrolysis progresses, ink-containing components such as pigments are deposited around the ink introduction port, and this deposit may block the flow path and the nozzle opening and cause discharge failure.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid ejecting head and a liquid ejecting apparatus capable of preventing liquid electrolysis caused by adhesion of conductive foreign matter. Is to provide.

In order to achieve the above object, a liquid jet head according to the present invention includes a flow path forming substrate for partitioning a liquid flow path including a pressure chamber communicating with a nozzle opening, and a diaphragm portion for changing the volume of the pressure chamber. And a flow path unit that forms a series of liquid flow paths including pressure chambers by joining the seal plate to the flow path forming substrate, and a sealing plate formed with a liquid introduction hole.
A vibrator unit having a piezoelectric vibrator having external electrodes formed on the outer surface;
A housing case for accommodating the transducer unit and a head case in which a case channel for supplying liquid to the liquid channel side of the channel unit is formed;
A liquid in which the flow path unit is joined to the head case in a state in which the diaphragm portion is disposed in the opening on the bottom side of the storage chamber and the case flow path and the liquid flow path communicate with each other through the liquid introduction hole. An ejection head,
An insulating portion is interposed between the diaphragm portion and the distal end surface of the free end portion of the piezoelectric vibrator.

  According to the above configuration, since the insulating portion is interposed between the diaphragm portion and the distal end surface of the free end portion of the piezoelectric vibrator, the insulating portion electrically connects the diaphragm portion and the distal end surface of the free end portion. Insulate. As a result, even if the diaphragm part and the surrounding support substrate are electrically short-circuited due to adhesion of a foreign substance having conductivity, the liquid introduction hole in the support substrate and the nozzle opening peripheral part in the nozzle formation substrate It is possible to prevent liquid electrolysis from occurring. As a result, it is possible to prevent problems such as ejection failure due to liquid-containing components being deposited by electrolysis.

  The said structure WHEREIN: The said sealing board is comprised by the composite board | plate material which bonds together the support substrate joined to a head case, and the elastic body film joined to a flow-path formation board | substrate. The support substrate has conductivity, and the elastic film has insulation properties.

In the above-described configuration, it is desirable to employ a configuration in which the insulating portion is formed by fixing an insulating material to a tip side portion that is a free end portion of the piezoelectric vibrator in the vibrator unit.
Moreover, the structure by which an insulation part is formed to the middle of the front end side part containing a front end surface is also employable.

  According to the above configuration, since the region to which the insulating material is fixed is provided in the portion other than the front end surface of the free end portion, even when the conductive foreign matter contacts the free end portion, the insulating material prevents short circuit. be able to.

  In this configuration, it is preferable to employ a configuration in which a resin is applied to the vibrator unit as the insulating material.

In the above configuration, the vibrator unit includes a piezoelectric body portion and an electrode portion, and is formed by dividing a vibrator base material to which an insulating material is fixed into a plurality of piezoelectric vibrators.
Each piezoelectric vibrator is formed by dividing the vibrator base material into comb teeth.

  According to this configuration, since the piezoelectric substrate is formed by dividing the vibrator base material after the insulating material is fixed, the gap between the piezoelectric vibrators can be prevented from being filled with the insulating material. it can. Further, the insulating material can be fixed to all the piezoelectric vibrators at once, which is convenient.

  According to another aspect of the invention, a liquid ejecting apparatus includes the liquid ejecting head having the above-described configuration.

  According to this configuration, since the liquid ejecting head capable of preventing the ejection failure due to the electrolysis of the liquid is mounted, it is possible to provide a highly reliable liquid ejecting apparatus.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the following, an ink jet recording head (hereinafter referred to as a recording head) mounted on the ink jet printer (hereinafter referred to as a printer) shown in FIG.

  The printer 1 includes a recording head 2 that is a kind of liquid ejecting head and a carriage 4 that is detachably mounted with an ink cartridge 3 that is a kind of a liquid storage member, and is disposed below the recording head 2, and is a recording sheet. A platen 5 on which 6 (a kind of discharge target) is conveyed, a carriage moving mechanism 7 for moving the carriage 4 in the paper width direction of the recording paper 6, and a paper feeding mechanism 8 for conveying the recording paper 6 in the paper feeding direction. In general, it is structured. Here, the paper width direction is the main scanning direction (head scanning direction), and the paper feeding direction is the sub-scanning direction (that is, the direction orthogonal to the head scanning direction). The ink cartridge 3 is not limited to the cartridge that is mounted on the carriage 4 as in the present embodiment, but is a cartridge that is mounted on the housing side of the printer 1 and is supplied to the recording head 2 via the ink supply tube. It can also be adopted.

  The carriage 4 is attached while being supported by a guide rod 9 installed in the main scanning direction, and is configured to move in the main scanning direction along the guide rod 9 by the operation of the carriage moving mechanism 7. ing. The position of the carriage 4 in the main scanning direction is detected by the linear encoder 10, and a detection signal is transmitted as position information to a control unit (not shown). Thus, the control unit can control the recording operation (discharge operation) and the like by the recording head 2 while recognizing the scanning position of the recording head 2 based on the position information from the linear encoder 10.

  Further, a home position serving as a scanning start point of the recording head 2 is set within the moving range of the recording head 2 and outside the platen 5. A capping mechanism 11 is provided at this home position. The capping mechanism 11 seals the nozzle forming surface of the recording head 2 with a cap member 11 ′ to prevent evaporation of the ink solvent from the nozzle opening 37 (see FIG. 2 and the like). The capping mechanism 11 is also used for a cleaning operation for applying a negative pressure to the sealed nozzle surface and forcibly sucking and discharging ink from the nozzle openings 37.

  FIG. 2 is a cross-sectional view of a main part illustrating the configuration of the recording head 2, and FIG. 3 is an exploded perspective view illustrating the configuration of the flow path unit. The illustrated recording head 2 includes an introduction needle unit 14 for standing an ink introduction needle 13, a vibrator unit 16 having a plurality of piezoelectric vibrators 15, and a flow path unit 17 for forming an ink flow path (a kind of liquid flow path). A head case 18 to which the vibrator unit 16 and the flow path unit 17 are fixed, a wiring board 28 for supplying a driving signal to the piezoelectric vibrator 15, and the like are schematically configured.

  The ink introduction needle 13 (a kind of liquid introduction needle) is a hollow needle-shaped member molded of synthetic resin, and the internal space of the ink (the liquid in the present invention) in a liquid storage member such as an ink cartridge or a sub tank (not shown). 1) is introduced into the needle channel 20. An introduction hole 21 communicating with the needle channel 20 is formed at the tip of the ink introduction needle 13, and when the ink introduction needle 13 is inserted into the liquid storage member, the liquid is stored through the introduction hole 21. The ink in the member is introduced into the needle channel 20.

  The introduction needle unit 14 is molded of synthetic resin in the same manner as the ink introduction needle 13, and an ink introduction path 22 corresponding to the ink introduction needle 13 is formed therein. The upstream end portion of the ink introduction path 22 has a funnel-like diameter expanded toward the introduction needle mounting side, and a filter 23 that filters out foreign matters in the ink is disposed in the opening portion. The ink introduction needle 13 is fixed on the introduction needle unit 14 by welding or the like in a state where the position of the downstream opening of the needle flow path 20 is superposed on the upstream opening of the ink introduction path 22. As a result, the ink introduction path 22 of the introduction needle unit 14 and the needle flow path 20 of the ink introduction needle 13 communicate with each other through the filter 23 in a liquid-tight state.

  As shown in FIG. 4, each piezoelectric vibrator 15 of the vibrator unit 16 is formed by cutting the vibrator base material 15 ′ into an extremely narrow width of about several tens of μm to 100 μm in a comb shape. Each piezoelectric vibrator 15 is in a so-called cantilever state in which a free end portion protrudes outward from the front end surface of the fixed plate 27 (the end surface on the flow path unit side when attached to the head case 18). The base end is fixed to the fixing plate 27. The piezoelectric vibrator 15 is a laminated piezoelectric vibrator formed by alternately laminating piezoelectric bodies (piezoelectric body portions) and internal electrodes (electrode portions), and has a vertical direction (elements) orthogonal to the electric field direction. This is a longitudinal vibration type piezoelectric vibrator that can be expanded and contracted in the longitudinal direction). Therefore, the free end of the piezoelectric vibrator 15 contracts in the longitudinal direction of the vibrator by charging, and the free end of the piezoelectric vibrator 15 extends in the longitudinal direction of the vibrator by discharging. A flexible cable 29 that supplies a drive signal from the wiring board 28 to the piezoelectric vibrator 15 is electrically connected to a base end portion of each piezoelectric vibrator 15. Details of the vibrator unit 16 will be described later.

  As shown in FIG. 3, the flow path unit 17 includes a nozzle plate 33, a flow path forming substrate 34, and a sealing plate 35 (vibrating plate). The nozzle plate 33 is attached to one surface of the flow path forming substrate 34. In addition, the sealing plate 35 is configured by arranging and laminating the sealing plate 35 on the other surface of the flow path forming substrate 34 opposite to the nozzle plate 33 and integrating them by adhesion or the like. The nozzle plate 33 disposed at the bottom of the flow path unit 17 is a thin plate made of stainless steel in which a plurality of nozzle openings 37 are opened in a row. In this embodiment, for example, 180 nozzle openings 37 are formed in a row at a pitch corresponding to 180 dpi, and the nozzle rows are configured by these nozzle openings 37. The nozzle plate 33 is adjusted to the ground potential through a metal cover (not shown) for the purpose of preventing static electricity and noise generated from recording paper or the like.

  The flow path forming substrate 34 is made of, for example, a silicon wafer, and has a flow path base portion that forms a series of ink flow paths (a kind of liquid flow path) including a common ink chamber 38, an ink supply port 39, and a pressure chamber 40. It is the formed plate-shaped member. Specifically, the pressure chamber empty portion 41 that becomes the pressure chamber 40, the groove portion 42 that becomes the ink supply port 39, the empty portion 43 that becomes the common ink chamber 38, and the like are formed on the flow path forming substrate 34 by etching processing. Yes. In addition, although the flow-path formation board | substrate in this embodiment is comprised by one plate, it may be comprised by laminating | stacking several plate members.

  The pressure chamber 40 is formed as a long and narrow chamber in a direction perpendicular to the direction in which the nozzle openings 37 are arranged (nozzle row direction), and the ink supply port 39 is provided between the pressure chamber 40 and the common ink chamber 38. It is formed as a narrowed portion (orifice) having a narrow channel width that communicates. The common ink chamber 38 is a chamber for temporarily storing ink introduced from the ink introduction needle 13 and supplied through the ink introduction path 22 and the case flow path 25. The ink stored in the common ink chamber 38 is distributed and supplied to each pressure chamber 40 through the ink supply port 39.

  The sealing plate 35 has a double structure in which an elastic film 46 made of an insulating flexible film such as PPS (polyphenylene sulfide) is laminated on a support substrate 45 made of a conductive plate material such as stainless steel. The elastic film 46 side surface is bonded to the flow path forming substrate 34 and the support substrate 45 side surface is bonded to the bottom surface of the head case 18. The sealing plate 35 is formed with a diaphragm 47 for sealing one opening surface of the pressure chamber 40 (pressure chamber empty portion 41) and changing the volume of the pressure chamber 40, and a common ink chamber. This is a member in which a compliance portion 48 that seals one opening surface of 38 (concave portion 43) is formed. The diaphragm portion 47 is formed by removing only the elastic film 46 by removing the surrounding support substrate 45 by etching while leaving a portion for joining the tip surface of the piezoelectric vibrator 15 as an island portion 49. It is configured. That is, the island portion 49 is independent from the other portions of the support substrate 45. The shape of the pressure chamber 40 is an elongated block shape in a direction perpendicular to the direction in which the nozzle openings 37 are arranged, like the planar shape of the pressure chamber 40.

  Further, the portion of the sealing plate 35 that functions as the compliance portion 48, that is, the portion corresponding to the common ink chamber 38, has the support substrate 45 removed substantially following the opening shape of the recess 43 of the flow path forming substrate 34, and the elastic body Only the film 46 is provided. When the compliance portion 48 is formed, an etching process is performed so that a part of the support substrate 45 in the sealing plate 35 remains as an apron portion 44 protruding from the edge of the compliance portion 48 toward the center side ( FIG. 3). In the apron portion 44, an ink introduction hole 50 (corresponding to a liquid introduction hole in the present invention) is opened in a state of penetrating the support substrate 45 and the elastic film 46. The ink introduction hole 50 communicates with a common ink chamber 38 that is a part of the ink flow path in a joined state with the flow path forming substrate 34, and communicates with the case flow path 25 in a joined state with the head case 18. . That is, the ink introduction hole 50 is a through hole for introducing the ink flowing down from the case flow path 25 side of the head case 18 to the common ink chamber 38 side. In this embodiment, the ink introduction hole 50 is formed as a circular hole. Has been.

  The head case 18 is a hollow block-shaped member made of synthetic resin, and the inside of the housing case 53 that can accommodate the vibrator unit 16 and the ink from the introduction needle unit 14 side are supplied to the flow channel unit 17 side. The case flow path 25 is formed. The accommodation chamber 53 of the head case 18 is formed in a series from the bottom surface of the head case 18 serving as the flow path unit attachment surface to the upper surface to which the introduction needle unit 14 and the wiring board 28 are attached. That is, the storage chamber 53 is formed as a through opening that passes through the height direction of the head case 18.

  First, the flow path unit 17 is joined to the head case 18. Specifically, the diaphragm portion 47 is disposed in the bottom opening of the storage chamber 53, and the case flow path 25 and the common ink chamber 38 (that is, the ink flow path) communicate with each other in a liquid-tight manner through the ink introduction hole 50. In this state, the flow path unit 17 is joined to the head case 18 by bonding the surface of the sealing plate 35 on the support substrate 45 side to the bottom surface of the head case 18 with an adhesive. As a result, the diaphragm portion 47 (island portion 49) faces the bottom opening of the storage chamber 53 of the head case 18. Next, the vibrator unit 16 is housed in the housing chamber 53 of the head case 18. In other words, the vibrator unit 16 is inserted from the upper surface side opening of the storage chamber 53 with the free end of the piezoelectric vibrator 15 at the head, and the tip of the free end is brought into contact with the surface of the corresponding island portion 49. In this state, it is stored in the storage chamber 53. Then, the tip of the free end portion of the piezoelectric vibrator 15 is joined to the island portion 49, and the fixing plate 27 is bonded to the inner wall surface of the accommodation chamber 53 to be fixed in the accommodation chamber 53.

  After the flow path unit 17 and the vibrator unit 16 are attached to the head case 18, a wiring board 28 is disposed on the upper surface of the head case 18, and wiring between the wiring board 28 and the flexible cable 29 is performed. Thereafter, the introduction needle unit 14 is attached to the upper surface of the head case 18 with the packing 24 interposed. As a result, the ink introduction path 22 of the introduction needle unit 14 communicates with the case flow path 25 of the head case 18 via the packing 24 in a liquid-tight manner. Therefore, the ink introduced from the introduction hole 21 of the ink introduction needle 13 passes through the ink introduction path 22 and the case flow path 25 from the ink introduction hole 50 to the ink flow path side of the flow path unit 17, that is, to the common ink chamber 38. Supplied.

  In the recording head 2 configured as described above, when a drive signal is applied from the wiring board 28 to the piezoelectric vibrator 15 through the flexible cable 29, the piezoelectric vibrator 15 expands and contracts in the longitudinal direction of the element. 49 moves in a direction close to or away from the pressure chamber 40. As a result, the volume of the pressure chamber 40 changes, and the pressure in the ink in the pressure chamber 40 varies. Due to this pressure fluctuation, an ink droplet (a kind of droplet) is ejected from the nozzle opening 37.

  Next, the vibrator unit 16 will be described. As shown in FIG. 5, each piezoelectric vibrator 15 (vibrator base material 15 ′) of the vibrator unit 16 includes a common internal electrode 55 and individual internal electrodes 56 (both of which are a kind of electrode portion), and is composed of zirconate titanate. It is a laminated piezoelectric vibrator formed by alternately laminating piezoelectric bodies 57 (a kind of piezoelectric body portion) made of lead oxide, barium titanate, or the like. Here, the common internal electrode 55 is an electrode having the same potential level (for example, ground potential) with respect to all the piezoelectric vibrators 15. The individual internal electrode 56 is an electrode whose potential level changes for each piezoelectric vibrator 15 according to the waveform of the drive signal. In the present embodiment, the free end portion 15a is a portion from the tip of the vibrator in the piezoelectric vibrator 15 to about half or about two-thirds of the vibrator longitudinal direction (direction orthogonal to the stacking direction). The remaining portion of the piezoelectric vibrator 15, that is, the portion from the base end of the free end portion 15a to the vibrator base end is defined as a base end portion 15b.

  The individual external electrode 30 (a kind of electrode portion) is formed in series on the tip surface portion of the piezoelectric vibrator 15 and the wiring connection surface (upper surface in FIG. 5) which is one side surface of the piezoelectric vibrator 15 in the stacking direction. The wiring terminal of the flexible cable 29 as a wiring member and each individual internal electrode 56 are electrically connected. And the part by the side of the wiring connection surface of this separate external electrode 30 is continuously formed toward the front end side from the base end part 15b. The common external electrode 31 (a kind of electrode portion) includes a base end surface portion of the piezoelectric vibrator 15, the above-described wiring connection surface, and a fixed plate mounting surface (the lower side in FIG. 5) that is the other side surface of the piezoelectric vibrator 15 in the stacking direction. The electrode is formed in series on the side surface) and conducts between the ground terminal of the flexible cable 29 and each common internal electrode 55. And the part by the side of the wiring connection surface in this common external electrode 31 is formed continuously from the near side to the base end face part side from the end part of the individual external electrode 30, and the part on the fixed part mounting face side is It is continuously formed from a position slightly ahead of the distal end surface portion of the vibrator toward the proximal end side.

  Said base end part 15b is a non-operation part which does not expand-contract. A flexible cable 29 is disposed on the wiring connection surface side of the base end portion 15b, and the individual external electrode 30 and the common external electrode 31 are electrically connected to the terminals of the flexible cable 29 on the base end portion 15b. . A drive signal is applied to each electrode through the flexible cable 29.

  In the free end portion 15a, an active region (an overlap portion indicated by a range A in FIG. 5) in which the common internal electrode 55 and the individual internal electrode 56 overlap each other is formed. When a potential difference is applied to these internal electrodes 55 and 56, the piezoelectric material 57 in the active region is deformed, and the free end portion 15a expands and contracts in the longitudinal direction of the vibrator. The base end of the common internal electrode 55 is electrically connected to the common external electrode 31 at the base end face portion of the piezoelectric vibrator 15. On the other hand, the tip of the individual internal electrode 56 is electrically connected to the individual external electrode 30 at the tip surface portion of the piezoelectric vibrator 15. Note that the distal end of the common internal electrode 55 is positioned slightly in front of the distal end surface portion of the piezoelectric vibrator 15 (base end surface side), and the proximal end of the individual internal electrode 56 is the boundary between the free end portion 15a and the proximal end portion 15b. Is located.

  Here, with respect to the sealing plate 35, in the conventional configuration, the island portion 49 which is a part of the conductive support substrate 45 is formed on the distal end surface side of the free end portion of the piezoelectric vibrator 15. Since it is directly joined to the external electrode 30, it has the same potential as the individual external electrode 30. On the other hand, the nozzle plate 33 disposed on the opposite side of the sealing plate 35 with the flow path forming substrate 34 interposed therebetween is adjusted to the ground potential as described above. Since the island portion 49 is electrically independent from the other portions of the support substrate 45, normally, even if a drive signal is applied to the piezoelectric vibrator 15, current flows from the island portion 49 to the other portions. There is no.

  However, as described above, since the diaphragm portion 47 is exposed in the bottom opening of the storage chamber 53 of the head case 18, for example, foreign matter such as processing waste is contained in the storage chamber of the head case 18 during the assembly process of the recording head 2. 53 may fall on the exposed portion including the diaphragm portion 47 and its peripheral portion. And when this foreign material has conductivity, such as a metal, and adheres between the island part 49 and the other part of the support substrate 45, there exists a possibility of electrically short-circuiting between both. . When such a short circuit occurs, in the conventional configuration, since the individual external electrode 30 on the front end surface of the piezoelectric vibrator 15 is directly joined to the island portion 49, almost the entire support substrate 45 is made of the piezoelectric vibrator 15. It becomes the same potential (positive potential) as the individual external electrode 30.

  As a result, conventionally, the inner peripheral surface of the ink introduction port, which is a portion in contact with the ink on the support substrate of the sealing plate, and the peripheral portion of the nozzle opening of the nozzle plate act as electrodes, and the ink between them is There was a case of electrolysis. As the electrolysis of the ink proceeds, ink-containing components such as pigments are deposited around the ink inlet, and this deposit may block the ink flow path and cause ejection failure.

  In view of such circumstances, in the recording head 2 according to the present invention, an insulating portion 59 is provided between the island portion 49 of the diaphragm portion 47 and the free end portion of the piezoelectric vibrator 15 as shown in FIG. By interposing, the island part 49 and the piezoelectric vibrator 15 (individual external electrode 30) are electrically insulated. Hereinafter, the insulating portion 59 will be described together with a method for manufacturing the vibrator unit 16.

  In the manufacturing method of the vibrator unit 16, first, the vibrator base material 15 ′ is manufactured. First, a polymerization region of the common internal electrode 55 and the individual internal electrode 56 is formed at the distal end portion that becomes the free end portion 15a, and only the common internal electrode 55 is non-polymerized at the proximal end portion that becomes the proximal end portion 15b. A laminated body is manufactured by alternately laminating and firing the piezoelectric body 57 (piezoelectric green sheet) between the common internal electrodes 55 and the individual internal electrodes 56 so that the region is formed (lamination process). . When the laminate is manufactured, the individual external electrodes 30 are formed in series in the front end surface portion of the laminate and the range from the front end to the base end portion 15b in the wiring connection surface, and the base end surface portion and the wiring of the laminate are formed. A common external electrode 31 is formed in series in a range from the base end to a part on the base end portion 15b on the connection surface and the fixing plate mounting surface without contacting the individual external electrode 30. A material 15 ′ is produced (external electrode forming step). When the vibrator base material 15 ′ is manufactured, the base end portion 15b of the vibrator base material 15 ′ is fixed in a so-called cantilever state in which the free end portion 15a protrudes outward from the distal end surface of the fixing plate 27. The base end portion of the plate mounting surface is fixed to the fixing plate 27 with an adhesive or the like.

  Subsequently, the insulating material 60 is fixed to the tip side portion of the vibrator substrate 15 ′. In the present embodiment, as shown in FIG. 7, a resin as an insulating material 60 is dipped in approximately half of the distal end side of the distal end portion that becomes the free end portion 15 a (below the imaginary line PP). Apply. As the insulating material 60, any material can be used as long as it has electrical insulation and can be fixed to the tip side portion of the vibrator substrate 15 ′. Based resins and the like. From the viewpoint of more reliably insulating between the island portion 29 and the individual external electrode 30, the thickness of the insulating material 60 (insulating portion 59) is determined at the tip surface of the vibrator base material 15 ′ (piezoelectric vibrator 15). It is desirable that it is thicker than the surface roughness of the individual external electrode 30.

  After the insulating material 60 is fixed to the tip side portion, the vibrator substrate 15 ′ is divided into individual piezoelectric vibrators 15. In the present embodiment, as shown in FIG. 5, in the vibrator base material 15 ′ before the division, from the joint edge A to the fixing plate 27 on the fixing portion mounting surface, B on the base end face portion of the vibrator base material 15 ′. An oblique cutting imaginary line L-L is set. Then, all parts of the active region of the vibrator substrate 15 ′ and a part above the cutting virtual line LL (on the wiring connection surface side) of the non-active region on the proximal end side are connected to a wire saw or dicing The individual piezoelectric vibrators 15 are formed by being divided into comb teeth with a gap corresponding to the arrangement pitch of the nozzle openings by a saw. In this way, by dividing the vibrator base material 15 ′ after the insulating material 60 is fixed, the insulating material 60 is securely fixed to the tip surface even when the arrangement pitch of the piezoelectric vibrators 15 is small. However, it is possible to prevent the gap between the adjacent piezoelectric vibrators 15 from being filled with the insulating material 60. Further, the insulating material 60 can be fixed to all the piezoelectric vibrators 15 at once, which is convenient.

  The vibrator unit 16 is created through the above steps. The vibrator unit 16 is inserted through the opening on the upper surface side of the head case 18 as described above, and the inside of the storage chamber 53 is in a state where the tip surface of the free end portion 15a is in contact with the surface of the corresponding island portion 49. Is housed. The distal end surface of the free end portion 15a is joined to the island portion 49 with an adhesive. In this embodiment, since the insulating material 60 is fixed in advance to the free end portion 15a, the insulating material 60 functions as the insulating portion 59, and the individual external electrode 30 formed on the surface of the free end portion 15a. And the island portion 49 (support substrate 45) are electrically insulated. Thereby, even when the island portion 49 and the entire support substrate 45 are short-circuited due to conductive foreign matter or the like, it is possible to prevent a current from flowing from the individual external electrode 30 to the support substrate 45 side. Thereby, electrolysis of ink can be prevented. As a result, it is possible to suppress ejection failure due to ink electrolysis. Further, in this embodiment, the insulating material 60 is fixed not only to the distal end surface of the free end portion 15a (tip end side portion) but also to almost half, so that, for example, a conductive foreign object contacts the free end portion 15a. Even in the case, the insulating material 60 can prevent a short circuit. Since the printer 1 includes the recording head 2 having the above-described configuration, it is possible to perform highly reliable ejection control.

  By the way, the present invention is not limited to the above embodiment, and various modifications can be made based on the description of the scope of claims.

With respect to the insulating portion 59, in the above embodiment, the insulating portion 59 is formed by fixing the insulating material 60 to substantially the half of the distal end side of the free end portion 15a (the distal end portion of the vibrator substrate 15 ′) including the distal end surface. Although the configuration is illustrated, the present invention is not limited to this, and it is only necessary that the insulating portion 59 is formed at least between the distal end surface of the free end portion 15a (vibrator base material 15 ') and the island portion 49. For example, as shown in FIG. 8A, an adhesive B1 is applied (transferred) to the tip surface of the free end portion 15a in advance, and dried and solidified to form the insulating portion 59 (FIG. 8B). Thereafter, the adhesive B2 is further applied to the insulating portion 59 (FIG. 8C), and the free end portion 15a and the island portion 49 may be joined by the adhesive B2 (FIG. 8C). d)).
In addition, an insulating portion 59 is formed in advance by applying and solidifying an adhesive or the like to the island portion 49 instead of the piezoelectric vibrator 15 (vibrator base material 15 ′) side, and then the free end portion 15a and the island portion are formed. The structure which joins 49 can also be employ | adopted.
Further, as the insulating portion 59, a gap material having electrical insulation may be interposed between the tip surface of the free end portion 15a and the island portion 49.

  In addition, the present invention is not limited to the printer described above, and can be applied to other liquid ejecting heads and liquid ejecting apparatuses as long as the vibrator unit and the sealing plate having the above-described configuration are provided. . For example, a display manufacturing apparatus that manufactures color filters such as liquid crystal displays, an electrode manufacturing apparatus that forms electrodes such as organic EL (Electro Luminescence) displays and FEDs (surface emitting displays), and chips that manufacture biochips (biochemical elements) The present invention can also be applied to a manufacturing apparatus or the like.

FIG. 2 is a perspective view illustrating a configuration of a printer. FIG. 3 is a cross-sectional view of a main part illustrating the configuration of a recording head. It is a disassembled perspective view explaining the structure of a flow path unit. It is a perspective view explaining the structure of a vibrator | oscillator unit. It is sectional drawing explaining the structure of a vibrator | oscillator unit (piezoelectric vibrator). It is principal part sectional drawing explaining the state which interposed the insulating part between the diaphragm part (island part) and the free end front-end | tip surface of a piezoelectric vibrator. It is a figure explaining the state which fixed the insulating material to the vibrator base material. It is a schematic diagram explaining the process of forming an insulating part in the front end surface of a free end part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording head, 15 ... Piezoelectric vibrator, 16 ... Vibrator unit, 17 ... Flow path unit, 18 ... Head case, 25 ... Case flow path, 30 ... Individual external electrode, 31 ... Common external electrode, 33 ... Nozzle plate, 34 ... Flow path forming substrate, 35 ... Sealing plate, 37 ... Nozzle opening, 38 ... Common ink chamber, 40 ... Pressure chamber, 45 ... Support substrate, 46 ... Elastic film, 47 ... Diaphragm part, 49 ... Island portion, 50 ... Ink introduction hole, 53 ... Storage chamber, 55 ... Common internal electrode, 56 ... Individual internal electrode, 57 ... Piezoelectric material, 59 ... Insulating portion, 60 ... Insulating material

Claims (9)

A flow path forming substrate for partitioning a liquid flow path including a pressure chamber communicating with the nozzle opening, and a sealing plate in which a diaphragm portion and a liquid introduction hole for varying the volume of the pressure chamber are formed. A flow path unit configured to form a series of liquid flow paths including a pressure chamber by bonding a sealing plate to the flow path forming substrate; and
A vibrator unit having a piezoelectric vibrator having external electrodes formed on the outer surface;
A housing case for accommodating the transducer unit and a head case in which a case channel for supplying liquid to the liquid channel side of the channel unit is formed;
A liquid in which the flow path unit is joined to the head case in a state in which the diaphragm portion is disposed in the opening on the bottom side of the storage chamber and the case flow path and the liquid flow path communicate with each other through the liquid introduction hole. An ejection head,
A liquid ejecting head, wherein an insulating portion is interposed between the diaphragm portion and a tip surface of a free end portion of the piezoelectric vibrator.   The said sealing board was comprised by the composite board | plate material which bonded together the support substrate joined to a head case, and the elastic body film joined to a flow-path formation board | substrate. Liquid jet head.   The liquid ejecting head according to claim 1, wherein the support substrate has conductivity, and the elastic film has insulating properties.   4. The insulating portion is formed by fixing an insulating material to a tip side portion which is a free end portion of the piezoelectric vibrator in the vibrator unit. 5. The liquid jet head described.   The liquid ejecting head according to claim 4, wherein the insulating portion is formed partway along a tip side portion including a tip surface.   The liquid ejecting head according to claim 4, wherein a resin is applied to the vibrator unit as the insulating material.   5. The vibrator unit according to claim 4, wherein the vibrator unit includes a piezoelectric body portion and an electrode portion, and is formed by dividing a vibrator base material to which an insulating material is fixed into a plurality of piezoelectric vibrators. Item 7. The liquid ejecting head according to any one of Items 6 to 6.   The liquid ejecting head according to claim 7, wherein each of the piezoelectric vibrators is formed by dividing the vibrator base material into comb teeth.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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