JP2012126028A - Inkjet head unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet head unit in which the interval of adjoining head chip arrays is narrowed by narrowing the width of an external wiring member for connection with the head chip without packaging a drive IC on the head chip itself.SOLUTION: The inkjet head unit includes: a head chip 20 including a plurality of nozzles arranged on the nozzle surface 21 and ejecting ink, respectively, from pressure chambers interconnected with the plurality of nozzles, respectively, by driving independent pressure generation means; a head unit base 10 which holds a plurality of head chips 20 arranged thereon; and an external wiring member which connects the pressure generation means and a drive circuit electrically. A wiring plate 30 is stacked on the head unit base 10 while being spaced apart therefrom, and the external wiring member is divided into a first external wiring member 40A for connection with the head chip, and a second external wiring member 41 that is connected via the wiring formed on the wiring plate 30.

Description

  The present invention relates to an ink jet head unit that forms a long nozzle row by arranging a plurality of head chips on a head unit base.

  2. Description of the Related Art Conventionally, as an inkjet head, an inkjet head configured by a head chip having a laminated structure manufactured using a semiconductor manufacturing technique is known (for example, Patent Document 1).

  A head chip of such an ink jet head includes a plurality of nozzles that eject ink, a plurality of pressure chambers that communicate with each nozzle, a diaphragm that forms one wall surface of the pressure chamber, and the diaphragm. Pressure generating means for discharging ink in the pressure chamber from the nozzles, an interposer layer (wiring layer) in which wiring paths for supplying power to each pressure generating means are formed, and formed so as to penetrate the interposer layer And an ink manifold for supplying ink into each pressure chamber through the formed ink flow path hole.

  By the way, since it is very difficult to obtain uniform ejection characteristics in the width direction when the nozzle row is elongated in order to obtain a desired recording width, an inkjet head generally has many head chips. An ink jet head unit configured so that the nozzles are arranged in a long length over a desired recording width as a whole is produced by using, for example, staggered arrangement on a common base member (head unit base). I am doing so.

  FIG. 13 and FIG. 14 show an example in which an ink jet head unit 1000 in which four head chips 1200 are arranged on one head unit base 1100 that is a base member. 13 is a plan view seen from the ink manifold side, and FIG. 14 is a cross-sectional view taken along line (a)-(a) of FIG.

  The head chip 1200 is arranged such that two rows along the X direction in the drawing are arranged in two rows in the Y direction in the drawing, and each row is shifted in the X direction, thereby shifting the four head chips 1200. Are arranged in a staggered pattern. In this case, the nozzles of each head chip 1200 (not visible in FIGS. 13 and 14) are arranged at a predetermined pitch along the X direction, and when viewed from the Y direction as a whole, all nozzles have the same pitch. It is comprised so that.

  Each head chip 1200 mounted on the inkjet head unit 1000 is formed such that an interposer layer 1202 protrudes laterally from the head chip body 1201, and a box-shaped ink manifold 1203 is formed on the upper surface of the interposer layer 1202. Is provided. External wiring members (FPC) 1204 and 1205 for supplying power are respectively connected to two opposing sides of the interposer layer 1202.

  The head unit base 1100 is formed with four openings 1101 through which the head chips 1200 are attached. The interposer layer 1202 of the head chip 1200 extends from the lower surface side of the head unit base 1100 to the periphery of the opening 1101. It is attached in contact. In each head chip 1200, one external wiring member 1204 located on both outer sides of the head unit base 1100 is directly pulled out from the side of the head unit base 1100 to the upper surface side, and the other external wiring member 1205 is connected to the head unit base 1100. Through a wiring lead hole 1102 penetratingly formed in 1100, the head unit base 1100 is led to the upper surface side and connected to a driving circuit board (not shown) on which a driving IC is mounted.

JP 2007-30361 A

  When an inkjet head unit is configured using a plurality of head chips having a laminated structure as in Patent Document 1, there are the following problems.

  For example, in a high-resolution head of about 1200 npi (nozzle per inch), positioning accuracy between the head chips is required on the order of several μm, and at the same time, high-density wiring is required. In general, an FPC (flexible printed circuit board) is used as an external wiring member connected to the head chip. However, in FPC, the density of wiring is limited to 600 dpi, and a common electrode common to each pressure generating means. Is also required.

  In FIG. 13, reference numeral 1300 denotes a common electrode wiring formed on the external wiring members 1204 and 1205, and is electrically connected to the common electrode 1206 wired to the interposer layer 1202 of each head chip 1200. Since the common electrode 1206 and the common electrode wiring 1300 are common to a large number of pressure generating means, they are formed wider than the individual wiring in consideration of the current density.

  For this reason, the external wiring members 1204 and 1205 connected to each head chip 1200 have a wider common electrode wiring 1300 in addition to the wiring electrically connected to the individual electrodes. Therefore, the external wiring member 1205 cannot be passed between the head chips 1200 in adjacent rows, and must be pulled out to the upper surface side of the head unit base 1100 through the wiring drawing hole 1102 as shown in the drawing. I was not getting. This is because each head chip 1200 is positioned so that the nozzles have an equal pitch along the X direction over the four head chips 1200, so that it is wider than the interval between two head chips 1200 adjacent in the X direction. This is because the external wiring member 1205 cannot pass therethrough.

  As a result, the space w in the Y direction between the two rows is not formed so wide that a space for forming the wiring lead hole 1102 between them and bending the external wiring member 1205 upward is required. There is a problem that the landing position deviation between the head chips 1200 in each row becomes large, resulting in a decrease in image quality.

  In order to solve this problem, a method of mounting a driving IC on the head chip itself is known. By mounting the driving IC on the head chip, the number of wirings can be reduced. As a result, the width of the external wiring board can be reduced, but there is a problem that the manufacturing difficulty is high and the yield is poor.

  Accordingly, the present invention provides an ink jet head unit in which a driving IC is not mounted on the head chip itself, but the external wiring member connected to the head chip is narrowed and the interval between adjacent head chip rows is narrowed. This is the issue.

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

  The above problems are solved by the following inventions.

According to a first aspect of the present invention, there is provided a head chip in which a plurality of nozzles are arranged on a nozzle surface and ink is ejected by driving pressure generating means independent from pressure chambers communicating with each of the plurality of nozzles, and the head An inkjet head unit having a plate-like head unit base for holding chips arranged in a plurality of rows, and an external wiring member for electrically connecting the pressure generating means and the drive circuit,
It has a wiring plate laminated with an interval with respect to the head unit base,
The external wiring member is divided into a first external wiring member connected to the head chip and a second external wiring member connected via a wiring formed on the wiring plate. Inkjet head unit.

According to a second aspect of the present invention, the pressure generating means is a capacitive load driven by a potential difference between two electrodes, and one electrode is a common electrode common to the other pressure generating means of the head chip. The other electrode is connected to an individual electrode independent by each pressure generating means,
The first external wiring member electrically connects only the individual electrode and the drive circuit,
The inkjet head unit according to claim 1, wherein the second external wiring member electrically connects at least the common electrode and the drive circuit.

According to a third aspect of the present invention, the head unit base has a mounting opening for mounting in a state where the head chip is inserted,
The head chip has an attachment hook portion formed so as to protrude sideways, and a terminal electrically connected to the individual electrode and a terminal electrically connected to the common electrode are formed on the surface of the attachment flange portion, respectively. And inserted from the nozzle surface side with respect to the mounting opening of the head unit base and fixed to the edge of the mounting opening by the mounting flange.
The wiring plate is provided on the opposite side of the head unit base across the mounting flange, and the wiring of the wiring plate and at least the terminal electrically connected to the common electrode are the surface of the mounting flange. 3. The ink jet head unit according to claim 2, wherein the ink jet head unit is electrically connected through an electrode protruding from the head.

  According to a fourth aspect of the present invention, the plurality of head chips are arranged in a staggered pattern in two or more rows on the head unit base, and each of the head chips is arranged on both sides in the row direction. The first external wiring member is connected so as to protrude, and one of the first external wiring members passes between the two head chips in an adjacent row and is lateral to the head unit base. 4. The ink jet head unit according to claim 1, wherein the ink jet head unit is drawn out.

  A fifth aspect of the present invention is the ink jet head unit according to any one of the first to fourth aspects, wherein a thickness of the wiring plate is larger than a thickness of the head unit base.

  According to the present invention, there is provided an ink jet head unit in which an external wiring member connected to a head chip is narrowed and an interval between adjacent head chips is narrowed without mounting a driving IC on the head chip itself. be able to.

The top view which looked at the ink jet head unit concerning the present invention from the ink manifold side Sectional view along (ii)-(ii) in FIG. The top view of the inkjet head unit which concerns on this invention of the state which abbreviate | omitted the wiring plate Sectional view showing the structure of the head chip Top view of the head chip Explanatory drawing of the assembly method of the inkjet head unit which concerns on this invention Explanatory drawing of the assembly method of the inkjet head unit which concerns on this invention Explanatory drawing of the assembly method of the inkjet head unit which concerns on this invention Explanatory drawing of the assembly method of the inkjet head unit which concerns on this invention Explanatory drawing of the assembly method of the inkjet head unit which concerns on this invention Explanatory drawing of the assembly method of the inkjet head unit which concerns on this invention Explanatory drawing of the other example of the assembly method of the inkjet head unit which concerns on this invention Plan view of a conventional ink jet head unit Sectional drawing which follows the (a)-(a) line of FIG.

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

  FIG. 1 is a plan view of an ink jet head unit according to the present invention as viewed from the ink manifold side, FIG. 2 is a cross-sectional view taken along lines (ii)-(ii) in FIG. 1, and FIG. It is a top view of the inkjet head unit of a state.

  The inkjet head unit 1 has a zigzag shape along the X direction in the figure so that four head chips 20 are arranged in two rows in the Y direction in the figure on one flat head unit base 10. It is arranged to become.

  Although an appropriate substrate material can be used for the head unit base 10, a glass plate is preferable in the present invention, and a heat-resistant glass substrate (for example, Tempax glass) can be preferably used. This is because the linear thermal expansion coefficient is small and the occurrence of distortion due to heat can be suppressed. In the head unit base 10, attachment openings 11 each having a rectangular shape in plan view are formed through the attachment portions of the head chips 20. Note that the X direction and the Y direction in the figure are orthogonal to each other in FIG.

  A large number of nozzles (not shown) are arranged in an array on the nozzle surface 21 of each head chip 20. When viewed from the Y direction in the figure, the nozzles span all four head chips 20. The head chips 20 are positioned and held in the mounting openings 11 of the head unit base 10 so that the pitches are equal to each other along the X direction in the drawing.

  Each head chip 20 is formed with two attachment flanges 22 that project greatly on both sides along the Y direction in the drawing. The nozzle surface 21 protrudes in the ink discharge direction from the position of the mounting flange 22, and an ink manifold 23 for storing ink is disposed on the opposite side of the nozzle surface 21 across the mounting flange 22. Is provided.

  A wiring plate 30 is laminated on the upper surface of the head unit base 10 with a slight gap.

  The wiring plate 30 is sufficiently thicker than the head unit base 10 and is formed in the same shape as the head unit base 10 in plan view. The wiring plate 30 can be formed of a Si (silicon) substrate, a glass substrate, a ceramic substrate, or the like. In particular, the same material as the head unit base 10 can have the same linear thermal expansion coefficient, It is preferable because adverse effects due to the above can be suppressed. Insertion holes 31 through which the ink manifolds 23 of the head chips 20 are inserted are formed in the same positions as the mounting openings 11 of the head unit base 10.

  Here, an example of the structure of the head chip will be described with reference to a cross-sectional view shown in FIG. 4 and a plan view shown in FIG. In FIG. 5, the ink manifold 23 is indicated by a broken line.

  In the head chip 20, a head chip body 50 and an interposer layer 60 are laminated and integrated. Here, the interposer layer 60 protrudes greatly on both sides of the head chip body 50 to form the mounting flange 22 described above, and the ink manifold 23 is provided on the upper surface of the interposer layer 60. . A heater 23a for heating the ink to a predetermined temperature is provided in the ink manifold 23.

The head chip body 50 includes a nozzle plate layer 51 formed of a Si substrate, an intermediate plate layer 52 formed of a glass substrate, a pressure chamber plate layer 53 formed of a Si substrate, and a SiO ₂ thin film from the lower layer side in the figure. And a diaphragm 54 formed. In the nozzle plate layer 51, a large number of nozzles 51a are opened on the lower surface and arranged in an array.

  In the pressure chamber plate layer 53, pressure chambers 53a for storing ink for ejection are formed corresponding to the nozzles 51a in a one-to-one correspondence, the upper wall is constituted by the diaphragm 54, and the lower wall is the middle. The plate layer 52 is used. The intermediate plate layer 52 is formed with a communication passage 52a through which the inside of the pressure chamber 53a communicates with the nozzle 51a.

  On the upper surface of the diaphragm 54, actuators 55 made of a thin film PZT, which is a pressure generating means for capacitive loads, are individually stacked in a one-to-one correspondence with the pressure chambers 53a. The actuator 55 has an upper electrode and a lower electrode (both not shown) laminated on the upper and lower sides, respectively, and is driven to be deformed by generating a potential difference between the two electrodes to vibrate the diaphragm 54, thereby causing a pressure chamber 53a. Energy for ejection is applied to the ink inside.

  A common electrode 56 is formed on the upper surface of the vibration plate 54 and is electrically connected to the lower electrodes of the plurality of actuators 55 in the head chip 20. A part of the surface of the common electrode 56 is formed with a protruding portion 56 a that protrudes from the surface upward (in the direction opposite to the nozzle surface 21). This protrusion 56a can be formed by, for example, a stud bump.

  The interposer layer 60 includes a substrate body 61 made of a Si substrate and an adhesive resin layer 62, and a gap corresponding to the thickness of the adhesive resin layer 62 is provided between the head chip body 50 and the substrate body 61, and The upper surface of the head chip body 50 is laminated so that a predetermined space is formed between the substrate body 61 and the diaphragm 54 in the areas of the actuators 55 and the protrusions 56a.

  The interposer layer 60 is formed with an ink flow path hole 63 penetrating vertically. One end (upper end) communicates with the inside of the ink manifold 23 and the other end (lower end) is a pressure of the head chip body 50. By communicating with the inside of the chamber 53a, ink in the ink manifold 23 can be introduced and supplied into the pressure chamber 53a.

  On the upper surface of the interposer layer 60, individual electrodes 64 that are individually connected to the upper electrodes of the actuators 55 are formed. One end of each individual electrode 64 is arranged at the end of each mounting flange 22 of the interposer layer 60, and the other end penetrates the substrate body 61 and is formed by a lower wiring 64 a formed on the lower surface of the substrate body 61. The corresponding upper electrode of the actuator 55 is electrically connected.

  An insulating protective layer is further laminated on the upper surface of the individual electrode 64, but is not shown here.

  One end of the interposer layer 60 on the lower surface of the substrate body 61 (between the substrate body 61 and the adhesive resin layer 62) is electrically connected to the protrusion 56a formed on the common electrode 56 of the head chip body 50. An electrode 65 is formed, and the other end penetrates the substrate main body 61 in each attachment flange 22, is exposed on the upper surface of the attachment flange 22, and protrudes greatly at the corresponding portion upward. 65a is formed. The protruding electrode portion 65a can be formed by, for example, a stud bump.

  Here, each head chip 20 has twelve nozzles 51 a, pressure chambers 53 a, and ink flow path holes 63. Therefore, as shown in FIG. 5, six individual electrodes 64 are arranged on each attachment flange 22 on the upper surface of the interposer layer 60. The common electrode is divided into three pieces at each mounting flange 22, and three protruding electrode portions 65 a are formed on the upper surface of the interposer layer 60.

  Note that, on the upper surface of the interposer layer 60, the individual electrodes 64 and the protruding electrode portions 65a are formed so as not to short-circuit each other.

  In the head chip 20 configured as described above, the nozzle surface 21 is inserted into each mounting opening 11 of the head unit base 10 from the upper surface side of the head unit base 10, and each mounting flange 22 is connected to the mounting opening 11. It is attached by making it contact | abut to the edge part which opposes. The head unit base 10 and the head chip 20 can be fixed with an adhesive described later after positioning.

  External wiring members 40A and 40B, which are the first external wiring members in the present invention, are electrically connected to each mounting collar 22 of each head chip 20 only with the individual electrodes 64 arranged on the upper surface of the mounting collar 22. It is joined to connect to. Here, FPC is used as the external wiring members 40A and 40B. The external wiring member 40A is joined to the mounting flanges 22 of the two head chips 20A in the upper row in the drawing in FIGS. 1 and 3, and the external wiring member 40B is on the lower side in the drawing in FIGS. The two head chips 20B in the row are joined to the mounting flanges 22 of the head chips 20B.

  Each of the external wiring members 40A and 40B is only electrically connected to only the individual electrode 64, and does not need to be electrically connected to the wide common electrode, so that the number of wirings is small. Therefore, it is formed narrower than before. For this reason, in the row of head chips 20A and the row of head chips 20B, the external wiring members 40A and 40B joined to the mounting flanges 22 on the outer side of each row are projected sideways as they are. The external wiring members 40A and 40B joined to the mounting flange 22 located between them pass between the head chips 20B and 20B in the adjacent row or between the head chips 20A and 20A, respectively, opposite to the head unit base 10. Can be pulled out to the side.

  The entire lower surface of the wiring plate 30 is an electrode 32 and is arranged above the head unit base 10 so that the portion of the ink manifold 23 of each head chip 20 is inserted into each insertion hole 31. Thereby, the electrode 32 on the lower surface of the wiring plate 30 and the protruding electrode portion 65a protruding from the upper surface of the mounting flange portion 22 of each head chip 20 are electrically connected. The electrode 32 and the protruding electrode portion 65a of the wiring plate 30 are joined by an epoxy resin adhesive 33 that also serves as NCP (insulating resin paste).

  As a result, the common electrode 56 of the head chip 20 is drawn out to the electrode 32 of the wiring plate 30 through the protruding portion 56a, the conductive electrode 65, and the protruding electrode portion 65a. A connection terminal portion 33 is formed on at least a part of the electrode 32 of the wiring plate 30, and the external wiring member 41, which is the second external wiring member in the present invention, is connected to the connection terminal portion 33 by, for example, solder or the like. Electrically connected. An FPC can be used for the external wiring member 41. However, since it is only necessary to conduct with the electrode 32 on the entire lower surface of the wiring plate 30, a general conductive wire such as a lead wire can also be used. .

  As shown in FIG. 2, the other ends of the external wiring members 40A and 40B and the external wiring member 41 are electrically connected to a driving circuit board 70 on which a driving IC 71 is mounted.

  Thus, in the inkjet head unit 1 according to the present invention, the external wiring member that is electrically connected to drive the actuator 55 of each head chip 20 is electrically connected to the individual electrode 64. 40A and 40B (first external wiring members) and an external wiring member 41 (second external wiring member) electrically connected to the common electrode 56 are separated, so that a driving IC is mounted on the head chip 20 itself. Without mounting, the external wiring members 40A and 40B that are electrically connected to the individual electrodes 64 of the head chip 20 can be narrowed. Therefore, it is not necessary to bend upward through the wiring lead holes formed between the rows of head chips as in the prior art, and between the head unit base 10 and the wiring plate 30 as it is, 20 and 20 can be pulled out to the opposite side, and the interval W between the row of head chips 20A and the row of head chips 20B can be reduced.

  In addition, since the inkjet head unit 1 is attached to the head unit base 10 with the attachment flange portions 22 of the head chips 20 coming into contact with the head unit base 10 from the upper surface side, the head unit base 10 is thin plate-shaped. Is formed. This is because the nozzle surface 21 of each head chip 20 needs to be as close as possible to the surface of the recording medium (not shown). In this case, although the strength of the head unit base 10 may be insufficient, a wiring plate 30 that is sufficiently thicker than the head unit base 10 is stacked in parallel with the head unit base 10 and supported by the protruding electrode portions 65a. Thus, the wiring plate 30 functions as a rigid reinforcing plate, and sufficient strength is imparted to the inkjet head unit 1.

  In the above embodiment, the entire lower surface of the wiring plate 20 is the electrode 32 and is electrically connected to the protruding electrode portion 65a so as to be electrically connected only to the common electrode 56 of each head chip 20. However, a part of the individual electrodes 64 of each head chip 20 may be electrically connected to the wiring plate 30 side. In this case, a protruding electrode portion similar to the protruding electrode portion 65 a is formed on a part of the individual electrode 64 by a stud bump or the like, and an electrode for the individual electrode is short-circuited to the electrode 32 on the lower surface of the wiring plate 30. Patterning should be done so as not to occur.

  When a part of the individual electrodes 64 is conducted to the wiring plate 30 as described above, the number of the individual electrodes 64 is to avoid complication of the second external wiring member electrically connected to the wiring plate 30. It is preferable that the ratio is 20% or less of all the individual electrodes 64 in the inkjet head unit 1.

  Next, an example of an assembly method of the inkjet head unit 1 will be described with reference to FIGS. Here, a transparent glass plate was used for the head unit base 10.

  First, after UV curing adhesive 100 is applied to the upper surface side periphery of the mounting opening 11 of the head unit base 10, the head chip 20 with the ink manifold not attached is adsorbed by the collet C, and the upper surface side of the mounting opening 11. The nozzle surface 21 is inserted through (FIG. 6). Here, the head chip 20 is temporarily positioned in the attachment opening 11 while being held by the collet C. It is not fixed yet in this state.

  Next, mutual alignment is performed using the camera K while confirming the head unit base 10 and the head chip 20 from the lower surface side of the head unit base 10 (FIG. 7).

  In this alignment method, for example, a metal alignment mark (not shown) having an appropriate shape is sputtered in advance on the periphery of the mounting opening 11 of the head unit base 10 and the lower surface side of the mounting flange 22 of the head chip 20. The position of the head chip 20 can be finely adjusted by the camera K so that the alignment marks coincide with each other. Since the head unit base 10 is formed of a transparent glass plate, it is possible to directly check each alignment mark and the portion of the mounting flange portion 22 of the head chip 20 with the camera K through this, and alignment is easy and highly accurate. Can be done.

  When the alignment marks match and the position of the head chip 20 is determined, the UV lamp U is irradiated with UV light from the lower surface side of the head unit base 10 to cure the applied UV curing adhesive 100, The head chip 20 is bonded and fixed to the head unit base 10 (FIG. 8). When the curing is completed, the adsorption of the collet C is released.

  Thereafter, similarly, the head chip 20 is positioned and fixed in each mounting opening 11.

  After all the head chips 20 are bonded and fixed to the head unit base 10, external wiring boards 40A and 40B (first external wiring members) are respectively attached to the individual electrodes arranged on the mounting flanges 22 of the head chips 20 by ACF ( It is electrically connected by thermocompression bonding via an anisotropic conductive film (FIG. 9).

  Next, the ink manifold 23 of each head chip 20 is joined, and the epoxy resin adhesive 33 is filled as NCP around the protruding electrode portion 65a (FIG. 10).

  Next, a wiring plate 30 having an electrode 32 previously formed on the lower surface is laminated from above, and the protruding electrode portions 65a and the electrodes 32 are electrically connected and bonded and fixed by an epoxy resin adhesive 33. (FIG. 11). At this time, the external wiring member 41 (second external wiring member) may be connected simultaneously.

  Thereby, the inkjet head unit 1 is completed.

  In the above assembling method, the confirmation position by the camera K and the irradiation position of the UV light are the same, but they can be arranged on the opposite side as shown in FIG.

  That is, the camera K may be disposed on the upper surface side of the head unit base 10 and the infrared light may be irradiated from the lower surface side by the infrared irradiation lamp R. Since Si used for the head chip 20 transmits infrared light, the head chip 20 can be aligned even if the light irradiation and the position of the camera K are opposite.

  After the positioning, the UV curable adhesive 100 may be cured by irradiating UV light from the same position using the UV irradiation lamp U instead of the infrared irradiation lamp R.

  According to this method, since the camera K and the irradiation means for infrared light and UV light can be disposed on the top and bottom surfaces of the head unit base 10, there is an advantage that the degree of freedom of installation of each device is high.

1: Inkjet head unit 10: Head unit base 11: Mounting opening 20: Head chip 21: Nozzle surface 22: Mounting flange 23: Ink manifold 23a: Heater 30: Wiring plate 31: Insertion hole 32: Electrode 33: Epoxy Resin adhesive 40A, 40B: External wiring member (first external wiring member)
41: External wiring member (second external wiring member)
50: head chip body 51: nozzle plate layer 51a: nozzle 52: intermediate plate layer 52a: communication path 53: pressure chamber plate layer 53a: pressure chamber 54: diaphragm 55: actuator 56: common electrode 56a: protrusion 60: interposer Layer 61: Substrate body 62: Adhesive resin layer 63: Ink flow path hole 64: Individual electrode 64a: Lower wiring 65: Conductive electrode 65a: Protruding electrode portion 70: Drive circuit board 71: Drive IC

Claims (5)

A plurality of nozzles are arranged on the nozzle surface, a head chip that ejects ink by driving pressure generating means independent from each pressure chamber communicating with each of the plurality of nozzles, and a plurality of the head chips are arranged and held. An ink jet head unit having a plate-like head unit base and an external wiring member that electrically connects the pressure generating means and the drive circuit,
It has a wiring plate laminated with an interval with respect to the head unit base,
The external wiring member is divided into a first external wiring member connected to the head chip and a second external wiring member connected via a wiring formed on the wiring plate. Inkjet head unit. The pressure generating means is a capacitive load driven by a potential difference between two electrodes, one electrode is connected to a common electrode common to the other pressure generating means of the head chip, and the other electrode is Each pressure generating means is connected to an independent individual electrode,
The first external wiring member electrically connects only the individual electrode and the drive circuit,
The inkjet head unit according to claim 1, wherein the second external wiring member electrically connects at least the common electrode and the drive circuit. The head unit base has a mounting opening for mounting with the head chip inserted,
The head chip has an attachment hook portion formed so as to protrude sideways, and a terminal electrically connected to the individual electrode and a terminal electrically connected to the common electrode are formed on the surface of the attachment flange portion, respectively. And inserted from the nozzle surface side with respect to the mounting opening of the head unit base and fixed to the edge of the mounting opening by the mounting flange.
The wiring plate is provided on the opposite side of the head unit base across the mounting flange, and the wiring of the wiring plate and at least the terminal electrically connected to the common electrode are the surface of the mounting flange. The inkjet head unit according to claim 2, wherein the inkjet head unit is electrically connected via an electrode protruding from the electrode.   The plurality of head chips are arranged in a staggered manner in two or more rows on the head unit base, and each of the head chips has the first external wiring member on both sides in the row direction. One of the first external wiring members is connected so as to protrude, and is drawn out to the side of the head unit base through two head chips in adjacent rows. The inkjet head unit according to claim 1, 2 or 3. 5. The inkjet head unit according to claim 1, wherein a thickness of the wiring plate is larger than a thickness of the head unit base.

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