JP2012025119A - Inkjet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet head of an independent driving type including a common electrode having a small current density in a limited space on a head chip without increasing the size of the head chip.SOLUTION: In a head chip 1, a connection electrode conducting with drive electrodes in drive channels 11A, 11B are formed on a back surface, common electrodes 17A, 17B commonly conducting with drive electrodes in a plurality of dummy channels 12A, 12B are formed on a front surface, and through-holes 16A, 16B penetrating from the front surface to the back surface, besides the drive channels 11A, 11B and the dummy channels 12A, 12B, are further provided. The common electrodes 17A, 17B are drawn out to the back surface of the head chip 1 through the through-holes 16A, 16B.

Description

  The present invention relates to an ink jet head, and more particularly to an ink jet head that can reduce the current density of a common electrode that conducts in common with a drive electrode in a dummy channel that does not discharge ink.

  The drive wall is deformed by applying a drive signal of a predetermined voltage to the drive electrode formed on the drive wall that divides the channel, and ink in the channel is ejected from the nozzle using the pressure generated at that time. As an ink jet head, one having a so-called harmonica type head chip in which opening portions of channels are respectively arranged on the front surface and the rear surface is known. Among them, an ink jet having an independent drive type head chip in which each channel in the channel row is divided into a drive channel that discharges ink and a dummy channel that does not discharge ink, and these are alternately arranged. There is a head. By alternately arranging the drive channels and the dummy channels, it is possible to simultaneously eject ink from all the drive channels.

  In an inkjet head having an independent drive type head chip, since the drive electrodes in each dummy channel can be commonly grounded or a common drive signal can be applied, conventionally, the drive electrodes of each dummy channel in the same channel row Are combined into one electrode (common electrode) on the surface where the channel of the head chip opens, thereby reducing the number of drive ICs and simplifying the electrical connection with the drive circuit. On the same surface as this surface, connection electrodes respectively connected to the drive electrodes of the respective drive channels are also individually formed (FIG. 15 of Patent Document 1, Patent Document 2, and FIGS. 2 and 16 of Patent Document 3). .

JP 2009-274327 A JP 2008-143167 A JP-A-8-197728

  In recent years, there has been a demand for further downsizing and higher density of ink jet heads, and further reduction in size and thickness of head chips is required. For this reason, as shown in FIG. 15 of Patent Document 1 and Patent Document 2, when a common electrode extending in parallel with the channel row is formed on the surface of the head chip, the space is limited, and an extremely narrow common electrode is formed. It can only be formed. In particular, in the case of a head chip having a plurality of channel rows in parallel, the space between the channel rows is extremely narrow, and it is difficult to form a wide common electrode therebetween.

  When the electrode width of the common electrode is small, the current density flowing therethrough increases, and excessive current flows, so that the ejection speed is affected, for example, the speed of the droplet ejected from the drive channel is reduced. In particular, when a pulse signal is used as a drive signal applied to the drive electrode, there is a property that the amount of current that flows instantaneously becomes very large, and an increase in current density becomes a big problem.

  As a method of reducing the current density without increasing the electrode width of the common electrode on the surface of the head chip, a method of increasing the thickness of the common electrode is conceivable. For example, a common electrode metal used for the head chip is used. In the case of aluminum, it is usually formed with a thickness of about 5 μm from the surface. It is difficult to form this thicker, for example, 10 μm or more, and it is not a realistic method to reduce the current density by controlling the thickness of the common electrode formed on the surface of the head chip.

  Accordingly, an object of the present invention is to provide an independent drive type ink jet head provided with a common electrode having a small current density in a limited space on the head chip without increasing the size of the head chip.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

The invention according to claim 1 has a channel row in which channels and drive walls made of piezoelectric elements are alternately arranged, and the openings of the channels are respectively arranged on the front surface and the rear surface, and the drive facing the channel. A drive electrode is formed on the wall, and the channel row includes a head chip in which a drive channel that discharges ink and a dummy channel that does not discharge ink are alternately arranged, and a voltage is applied to the drive electrode. An ink jet head that ejects ink in the drive channel from a nozzle disposed in front of the head chip by applying
In the head chip, a connection electrode that is electrically connected to the drive electrode in the drive channel is formed on the rear surface, and a common electrode that is electrically connected to the drive electrode in the plurality of dummy channels is formed on the front surface. And, in addition to the drive channel and the dummy channel, has a through-hole penetrating from the front surface to the rear surface,
The common electrode is an ink-jet head that is drawn to the rear surface of the head chip through the through hole.

According to a second aspect of the present invention, a plurality of the through holes are provided in the head chip,
The inkjet head according to claim 1, wherein the common electrode is drawn out to a rear surface of the head chip through the plurality of through holes.

  A third aspect of the present invention is the ink jet head according to the first or second aspect, wherein the through hole is disposed outside the channel row in the direction of the channel row.

In the invention according to claim 4, the head chip has a plurality of channel rows arranged in parallel,
4. The ink jet head according to claim 1, wherein the through hole and the common electrode are provided for each channel row.

  According to a fifth aspect of the present invention, the inkjet head further includes a wiring substrate bonded to the rear surface of the head chip, and the wiring substrate is provided on the connection electrode and the common electrode drawn on the rear surface, respectively. The inkjet head according to any one of claims 1 to 4, further comprising a plurality of wiring electrodes connected correspondingly.

  According to the present invention, it is possible to provide an independently driven ink jet head provided with a common electrode having a small current density in a limited space on the head chip without increasing the size of the head chip.

1 is an exploded perspective view of an inkjet head according to the present invention. Partial front view of the head chip Partial rear view of the head chip Sectional view along line (iv)-(iv) in FIG. Partial expanded sectional view of E1 area in FIG. Partial expanded sectional view of E2 area in FIG. Partial expanded sectional view of the E3 region in FIG. Explanatory drawing of an example of the manufacturing method of the inkjet head which concerns on this invention Explanatory drawing of an example of the manufacturing method of the inkjet head which concerns on this invention Explanatory drawing of an example of the manufacturing method of the inkjet head which concerns on this invention Explanatory drawing of an example of the manufacturing method of the inkjet head which concerns on this invention Explanatory drawing of an example of the manufacturing method of the inkjet head which concerns on this invention Explanatory drawing of an example of the manufacturing method of the inkjet head which concerns on this invention

  The head chip in the present invention has a channel row in which channels and drive walls made of piezoelectric elements are alternately arranged. The head chip is arranged with channel openings facing the front and rear surfaces, respectively. Each channel is formed in a straight shape whose cross-sectional shape does not change from the rear opening (channel inlet) to the front opening (channel outlet), and a drive electrode is formed on the surface of the drive wall facing each channel. Is done. Such a head chip is a so-called harmonica type head chip made of a hexahedron, and by applying a drive signal of a predetermined voltage sent from the drive circuit to each drive electrode on both sides of the drive wall, the drive wall is shear-deformed, A change in pressure for ejection is applied to the ink supplied into the channel, and the ink is ejected as an ink droplet from a nozzle disposed on the front surface of the head chip.

  In the present invention, in such a hexahedral harmonica type head chip, a surface on which nozzles are arranged and ink is ejected is defined as a “front surface”, and a surface on the opposite side is defined as a “rear surface”. A direction parallel to the front surface or the rear surface of the head chip and away from the head chip is defined as “side” of the head chip.

  The channel row in the present invention is an independent drive type head chip in which drive channels and dummy channels are alternately arranged. A drive channel connection electrode that is electrically connected to the drive electrode in the drive channel is individually formed on the rear surface of the head chip, and a common electrode that is electrically conductive only to the drive electrodes in the plurality of dummy channels is formed on the front surface. ing.

  The drive channel is a channel that ejects ink from nozzles according to image data during image recording, and the dummy channel is a channel that does not always eject ink regardless of image data. Since the dummy channel does not need to eject ink, generally, the opening on the inlet side is closed and the ink is not filled, or the nozzle corresponding to the dummy channel is not formed on the nozzle plate.

  In addition to the drive channel and the dummy channel, the head chip has a through-hole penetrating from the front surface to the rear surface. The through hole preferably has a channel structure. This is because the groove can be easily formed simultaneously with the drive channel and the dummy channel when the head chip is manufactured. A through hole having a channel structure is a channel that does not discharge ink, similar to the dummy channel.

  The common electrode formed on the front surface of the head chip passes through the through hole and is electrically drawn out to the rear surface of the head chip. Therefore, there is no drive channel connection electrode on the front surface of the head chip, and only a common electrode can be formed. Therefore, a sufficiently wide wide area with a small current density is formed using this front surface. Can do. For this reason, the resistance of the common electrode can be made sufficiently small, and stable injection can be performed.

  In addition, since the connection electrodes corresponding to the drive channels are arranged on the surface of the head chip, and one end of the common electrode is disposed through the through hole, each connection electrode and the common electrode are arranged on the rear surface of the head chip. It is possible to apply a drive signal. At one end of the common electrode drawn out on the rear surface of the head chip, a connection part for applying a drive signal is formed.

  Since the common electrode passes through the through hole, the electrode portion is not exposed on the surface, and there is no fear of a short circuit due to adhesion of moisture such as dust or ink. In addition, since two or more surfaces such as the bottom surface and the side surface of the inner surface of the through hole can be used, it is more than the case where the electrode is wired and conducted in a plane using only one surface of the head chip surface. The electrical connection area can be taken. Therefore, it is highly reliable. In addition, since there is no need to use extra parts to route the electrodes, it does not hinder the compactness of the inkjet head.

  In addition, since the channel structure is the same as that of the drive channel and the dummy channel, there is no restriction on the aspect ratio as in the case of a normal through-electrode drilling process, so the L length (the length of the drive portion of the channel in the ink ejection direction) Even if is long, it can respond.

  In order for the common electrode to pass through the through hole, a through electrode made of a metal film conducting to the common electrode is formed on the inner surface of the through hole. Further, the entire inside of the through hole may be filled with a metal material such as a conductive paste to be electrically connected to the common electrode, and further, the common electrode may be formed by embedding a metal wire such as an Al wire or a Cu wire in the through hole. And may be conducted. By filling the inside of the through hole with a metal material or a metal wire, the resistance value at the through hole portion can be lowered.

  When the through hole has a channel structure, the through electrode made of a metal film can be formed in the through hole simultaneously with the formation of the drive electrode in the drive channel and the dummy channel.

  A plurality of through holes are preferably provided in the head chip. In this case, the common electrode is drawn out to the rear surface of the head chip through the plurality of through holes. Thus, even if the common electrode is drawn out to the rear surface of the head chip using a plurality of through holes, the resistance value in the through hole portion can be lowered.

  The through holes are preferably arranged outside the channel row in the channel row direction (on the end side of the head chip in the channel direction). Accordingly, it is easy to distinguish and arrange the connection electrode on the rear surface of the head chip and the connection portion of the common electrode disposed on the rear surface without crossing (short-circuiting). The through hole may be provided outside either one of the channel row directions.

  In the present invention, the head chip may have a plurality of channel rows arranged in parallel. Each channel row has drive channels and dummy channels alternately. In this case, the through hole is provided for each channel row, and the common electrode is provided so as not to be short-circuited between the channel rows.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 is an exploded perspective view of an inkjet head according to the present invention, FIG. 2 is a partial front view of the head chip, FIG. 3 is a partial rear view of the head chip, and FIG. 4 is a line (iv)-(iv) in FIG. 5 is a partially enlarged sectional view of the E1 region in FIG. 4, FIG. 6 is a partially enlarged sectional view of the E2 region in FIG. 4, and FIG. 7 is a partially enlarged sectional view of the E3 region in FIG. is there.

  In FIG. 1, 1 is a harmonica type head chip, 2 is a nozzle plate, 3 is a wiring board, and 4 is an electrical wiring member.

  The head chip 1 has two channel rows of A row and B row. Here, the lower channel row in FIGS. 2 and 3 is the A column, and the upper channel row is the B column. In each channel row, drive channels 11A and 11B and dummy channels 12A and 12B are alternately arranged. A drive wall 13A or 13B made of a piezoelectric element is formed between the adjacent drive channel 11A or 11B and the dummy channel 12A or 12B. The drive channels 11A and 11B and the dummy channels 12A and 12B are opened on the front surface 1a and the rear surface 1b of the head chip 1, and the drive electrodes 14A and 14B are formed in close contact with the inner surfaces.

  On the rear surface 1b of the head chip 1, connection electrodes 15A and 15B, one end of which is electrically connected to the drive electrodes 14A and 14B in the drive channels 11A and 11B, are formed. The other end of each connection electrode 15A, 15B extends to one end edge 1c parallel to the channel row on the rear surface 1b of the head chip 1 in the A row, and is arranged at the same pitch as each drive channel 11A on the end edge 1c. Yes. In the B row, it passes through the drive wall 13A between the adjacent drive channel 11A and the dummy channel 12A in the A row, extends to the end edge 1c, and is arranged alternately with the connection electrodes 15A.

  A plurality of through holes 16 </ b> A and 16 </ b> B that penetrate from the front surface 1 a to the rear surface 1 b of the head chip 1 are provided outside the channel rows in the A row and the B row in the channel row direction. Each through-hole 16A, 16B has the same channel structure as the drive channels 11A, 11B and the dummy channels 12A, 12B.

  On the front surface 1a of the head chip 1, wide common electrodes 17A and 17B extending in the channel row direction are separately formed so as not to be short-circuited for each channel row. Each of the common electrodes 17A and 17B surrounds a corresponding channel row and is spaced from the periphery of the opening of the drive channels 11A and 11B, but enters the inside from the opening of each of the dummy channels 12A and 12B. These are electrically connected only to the drive electrodes 14A and 14B in the dummy channels 12A and 12B (see FIG. 5).

  The common electrodes 17A and 17B are provided so as to surround all the corresponding through holes 16A and 16B in the A row or the B row, respectively. As shown in FIG. 5, through electrodes 161A and 161B made of a metal film are formed on the inner surfaces of the through holes 16A and 16B. The common electrodes 17A and 17B are openings on the front surface 1a side of the through holes 16A and 16B. And penetrates through electrodes 161A and 161B (see FIG. 6).

  2 to 4, reference numeral 18 denotes an adhesive receiving groove for receiving surplus adhesive when the head chip 1 described later is manufactured. Here, the plurality of adhesive receiving grooves 18 are arranged along the channel row direction between the outermost channel of the channel row of the A row and the through holes 16A. The common electrode 17A is provided so as to be separated from the periphery of the opening on the front surface 1a side of the adhesive receiving groove 18.

  The common electrodes 17A and 17B provided on the front surface 1a of the head chip 1 are electrically drawn out to the rear surface 1b of the head chip 1 through the through electrodes 161A and 161B in the through holes 16A and 16B. Connection portions 171A and 171B on the rear surface 1b side of the common electrodes 17A and 17B are provided on the rear surface 1b of the head chip 1 so as to surround the openings of the through holes 16A and 16B. The connecting portions 171A and 171B enter the inside through the openings on the rear surface 1b side of the through holes 16A and 16B and are electrically connected to the through electrodes 161A and 161B (see FIG. 7).

  The connecting portion 171A has an area large enough to surround all the through holes 16A, and extends to the end surface 1c of the head chip 1 with a wide width in the same manner as the connecting electrodes 15A and 15B. In addition, the connection electrode 171B has an area large enough to surround all the through holes 16B, surrounds all the openings on the rear surface 1b side of the adhesive receiving groove 18, and is connected to the connection portion 171A and the outermost channel of the A row. , And extends to the end face 1c of the head chip 1 in a wide manner in the same manner as the connecting portion 171A. Therefore, in addition to the connection electrodes 15A and 15B, the connection portions 171A and 171B of the common electrodes 17A and 17B are also arranged on the edge 1c of the rear surface 1b of the head chip 1 on the outer side.

  5 to 7, reference numeral 19 denotes an insulating protective film such as a parylene film formed on the surface of the head chip 1. The insulating protective film 19 covers the respective surfaces of the drive electrodes 14A and 14B, the connection electrodes 15A and 15B, the common electrodes 17A and 17B, the connection portions 171A and 171B, and the through electrodes 161A and 161B and protects them from contact with ink. .

  The nozzle plate 2 is bonded to the front surface 1 a of the head chip 1. In the nozzle plate 2, nozzles 21 are opened only at positions corresponding to the drive channels 121 in the A and B rows.

  The wiring substrate 3 is bonded to the rear surface 1b of the head chip 1 with an adhesive. The wiring substrate 3 is a substrate formed in a flat plate shape larger than the rear surface 1b of the head chip 1 by using, for example, glass, silicon, ceramics or the like. In the bonding region (region indicated by the alternate long and short dash line in FIG. 1) 31 to be bonded to the rear surface 1b of the head chip 1, wiring is provided only at positions corresponding to the drive channels 11A and 11B opened on the rear surface 1b of the head chip 1. Ink supply ports 32A and 32B for supplying ink in common to the drive channels 11A and 11B from a common ink chamber (not shown) provided on the back side of the substrate 3 (the side opposite to the head chip 1) are individually provided. It has been established. Therefore, the openings on the inlet side of the dummy channels 12A and 12B of the head chip 1 are blocked by the wiring board 3 so that ink is not supplied from the common ink chamber. Further, the through holes 16 </ b> A and 16 </ b> B and the rear surface 1 b side of the adhesive receiving groove 18 are also closed by the wiring board 3.

  A wiring electrode 33A that is electrically connected to each of the connection electrodes 15A and 15B arranged on the rear surface 1b of the head chip 1 is provided on a surface (hereinafter referred to as a surface) of the wiring substrate 3 that is bonded to the head chip 1. , 33B and the connection electrodes 171A, 171B of the common electrodes 17A, 17B are vapor-deposited so that the wiring electrodes 34A, 34B extend in a direction perpendicular to the channel row of the head chip 1 on the surface of the wiring substrate 3. Alternatively, it is formed by sputtering or the like.

  One end of each of the wiring electrodes 33A and 33B is located in the bonding region 31 so as to be in contact with each connection electrode 15A and 141 of the head chip 1, and the other end is a lateral side perpendicular to the channel row of the head chip 1 from the bonding region 31. Extends to the end 3a of the wiring board 3 projecting over and arranged at the end 3a. Similarly, one end of each of the wiring electrodes 34A and 34B is located in the bonding region 31 so as to come into contact with each connection portion 171A and 171B of the head chip 1, and the other end similarly extends to the end portion 3a of the wiring substrate 3. They are arranged at the end 3a.

  The electrical wiring member 4 is joined to the end 3a on the front surface side of the wiring board 3, and drive signals from a drive circuit (not shown) are sent to the wiring electrodes 33A, 33B, 34A, 34B, connection electrodes 15A, 15B, The common electrodes 17A and 17B are applied to the drive electrodes 14A and 14B, respectively. As the electrical wiring member 4, a flexible printed circuit board (FPC) can be preferably used.

  Next, an example of a method for manufacturing such an ink jet head will be described with reference to FIGS.

  First, each of the polarized piezoelectric material substrates 101 and 102 is prepared, laminated with their polarization directions (indicated by arrows in FIG. 8) being different, and bonded with an epoxy adhesive to produce the laminated substrate 100. To do. A resist 103 is formed in advance on the upper surface of the upper piezoelectric material substrate 102, and a plurality of channel grooves 104 to be drive channels and dummy channels later are formed using a dicing saw 400 from the upper surface side, and through holes are formed later. A plurality of channel grooves 105 are processed. In this step, a plurality of grooves 106 serving as adhesive receiving grooves are also processed between the channel grooves 104 and 105. Each of the channel grooves 104 and 105 is formed in a parallel groove shape at a predetermined depth from one end to the other end of the multilayer substrate 100 and reaching the middle portion of the lower piezoelectric material substrate 101. Each groove 106 is also formed in a parallel groove shape with a predetermined depth from one end of the laminated substrate 100 to the other end. (FIG. 8).

  Next, a metal film is formed by vapor deposition or sputtering from the upper surface side of the laminated substrate 100 in which the channel grooves 104 and 105 and the groove 106 are formed, and then the resist 103 is removed, whereby each channel that becomes a drive channel and a dummy channel is obtained. The drive electrode 14 is formed by the metal film remaining on the entire inner surface (both side surfaces and bottom surface) of the groove 104, and the through electrode 161 is formed by the metal film remaining on the entire inner surface (both side surfaces and bottom surface) of each channel groove 105 serving as a through hole. Is formed (FIG. 9).

  At this time, the metal film also remains on the entire inner surface of each groove 106 serving as an adhesive receiving groove.

  Next, on the upper surface of the multilayer substrate 100 on which the drive electrode 14 and the through electrode 161 are formed, the multilayer substrate 100 ′ in which the channel grooves 104 and 105 and the groove 106 and the drive electrode 14 and the through electrode 161 are formed is similarly laminated. Further, a cover substrate 200 made of the same piezoelectric material substrate (non-polarized) as the piezoelectric material substrates 101 and 102 is coated on the upper surface of the multilayer substrate 100 ′, and these are bonded to each other with an epoxy adhesive. Accordingly, the upper portions of the channel grooves 104 and 105 and the grooves 106 of the multilayer substrate 100 are blocked by the multilayer substrate 100 ′, and the upper portions of the channel grooves 104 and 105 of the multilayer substrate 100 ′ are blocked by the cover substrate 200. Then, two channel rows in which the drive channel 11 and the dummy channel 12 are alternately formed, a plurality of through holes 16, and a plurality of adhesive receiving grooves 18 between the laminated substrates 100 and 100 ′ are formed (FIG. 10).

  Here, the adhesive receiving groove 18 need not be formed in the upper laminated substrate 100 ′. The adhesive receiving groove 18 receives surplus adhesive of the adhesive layer formed between the lower laminated substrate 100 and the upper laminated substrate 100 ′, and discharges bubbles in the adhesive layer. As a result, the connecting portion 171B (see FIG. 3) formed so as to straddle between the laminated substrates 100 and 100 ′ on the rear surface 1b of the head chip 1 can be surely conducted between the laminated substrates 100 and 100 ′. I have to.

  In this way, the laminated substrates 100 and 100 ′ and the cover substrate 200 are laminated in such a manner that the opening surfaces of the channels 11 and 12 are the same, so that the head substrate 300 has two channel rows. Is made. Since the obtained head substrate 300 is a long substrate with the channels 11 and 12 being long, a dicing saw is used so that the length of the channels 11 and 12 becomes a desired length (L length). A plurality of head chips 1 are produced from one head substrate 300 by full cutting in the direction orthogonal to the length direction of each channel 11 and 12 along the line cc in FIG. 11).

  Next, a dry film 500 is adhered to each of the front surface 1a and the rear surface 1b of the head chip 1, and regions 501A and 501B in which common electrodes are to be formed on the front surface 1a and connection electrodes on the rear surface 1b are formed by exposure and development. The dry film 500 in the regions 503A and 503B where the regions 502A and 502B and the common electrode connection portion are to be formed is removed. Thereby, the front surface 1a of the head chip 1 is exposed in each of the regions 501A and 501B, and the rear surface 1b of the head chip 1 is exposed in each of the regions 502A, 502B, 503A, and 503B (FIGS. 12 and 13).

  In the areas 501A and 501B of the front surface 1a, the openings of the dummy channels 12A and 12B and the openings of the through holes 16A and 16B are exposed, but the openings of the drive channels 11A and 11B and the adhesive are exposed. Each opening of the receiving groove 18 is closed with a dry film 500.

  Further, the regions 502A and 502B on the rear surface 1b are exposed to be connected to the openings of the drive channels 11A and 11B, but the openings of the dummy channels 12A and 12B are blocked by the dry film 500. .

  Further, the openings of the dummy channels 12A and 12B, the openings of the through holes 16A and 16B, and the openings of the adhesive receiving groove 18 are exposed in the regions 503A and 503B of the rear surface 1b.

  Thereafter, a metal film is formed on the front surface 1a and the rear surface 1b of the head chip 1 by vapor deposition or sputtering. The metal film enters the inside from the openings of the dummy channels 12A and 12B and the openings of the through holes 16A and 16B on the front surface 1a side, and is electrically connected to the drive electrodes 14A and 14B and the through electrodes 161A and 161B.

  On the rear surface 1b, the metal film penetrates into the openings from the openings of the drive channels 11A and 11B and the openings of the through holes 16A and 16B, and is electrically connected to the drive electrodes 14A and 14B and the through electrodes 161A and 161B, respectively. At this time, the metal film also enters the inside of the adhesive receiving groove 18 exposed on the rear surface 1b. However, since the front surface 1a side of the adhesive receiving groove 18 is covered with the dry film 500, the adhesive receiving groove There is no short circuit with the metal film on the side of the front surface 1a via the metal film in 18.

  After the metal film is formed in this way, the dry film 500 is removed, so that the common electrodes 17A and 17B are respectively formed in the regions 501A and 501B of the front surface 1a by the metal film as shown in FIGS. The connection electrodes 15A and 15B are respectively formed in the regions 502A and 502B of the rear surface 1b, and the connection portions 171A and 171B of the common electrodes 17A and 17B are respectively formed in the regions 503A and 503B of the rear surface 1b. The

  Thereafter, an insulating protective film 19 for protecting each electrode is formed on the outer surface other than the rear surface 1b of the head chip 1, the surfaces of the drive electrodes 14A and 14B, and the surfaces of the through electrodes 161A and 161B.

  The nozzle plate 2 on which the nozzles 21 are formed is bonded to the front surface 1a of the head chip 1 thus manufactured by an epoxy adhesive, and the ink supply ports 32A and 32B and the wiring electrodes 33A are connected to the rear surface 1b. The wiring board 3 on which the 33B, 34A, and 34B are formed is connected to the connection electrodes 15A and 15B and the connection portions 171A and 171B and the wiring electrodes 33A, 33B, and 34A by using an epoxy adhesive or an anisotropic conductive adhesive. 34B is joined so as to be electrically connected to each other, and a manifold (not shown) is joined to the back side of the wiring board 3 with an epoxy adhesive.

  An electrical wiring member 4 for applying a drive signal from a drive circuit (not shown) is joined to the end 3a of the wiring board 3 via an anisotropic conductive film or the like.

1: Head chip 1a: Front surface 1b: Rear surface 1c: Edge 11A, 11B: Drive channel 12A, 12B: Dummy channel 13A, 13B: Drive wall 14A, 14B: Drive electrode 15A, 15B: Connection electrode 16A, 16B: Through-hole 161A, 161B: Through electrode 17A, 17B: Common electrode 171A, 171B: Common electrode connecting portion 18: Adhesive receiving groove 19: Insulating protective film 2: Nozzle plate 21: Nozzle 3: Wiring substrate 31: Bonding region 32A, 32B : Ink supply port 33A, 33B: Wiring electrode 34A, 34B: Wiring electrode 4: Electric wiring member

Claims (5)

It has a channel row in which channels and drive walls made of piezoelectric elements are alternately arranged, and openings of the channels are arranged on the front and rear surfaces, respectively, and drive electrodes are formed on the drive walls facing the channels. And a head chip in which a drive channel for discharging ink and a dummy channel for not discharging ink are alternately arranged in the channel row, and applying the voltage to the drive electrode allows the driving to be performed. An ink jet head that discharges ink in a channel from a nozzle disposed on a front surface of the head chip,
In the head chip, a connection electrode that is electrically connected to the drive electrode in the drive channel is formed on the rear surface, and a common electrode that is electrically connected to the drive electrode in the plurality of dummy channels is formed on the front surface. And, in addition to the drive channel and the dummy channel, has a through-hole penetrating from the front surface to the rear surface,
The ink jet head according to claim 1, wherein the common electrode is drawn out to a rear surface of the head chip through the through hole. A plurality of the through holes are provided in the head chip,
The inkjet head according to claim 1, wherein the common electrode is drawn out to a rear surface of the head chip through the plurality of through holes.   The inkjet head according to claim 1, wherein the through hole is disposed outside the channel row in the channel row direction. The head chip has a plurality of juxtaposed channel rows,
4. The ink jet head according to claim 1, wherein the through hole and the common electrode are provided for each of the channel rows. The inkjet head further includes a wiring substrate bonded to the rear surface of the head chip,
5. The wiring board according to claim 1, wherein the wiring board includes a plurality of wiring electrodes connected to the connection electrode and the common electrode drawn out to the rear surface, respectively. Inkjet head.

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