JP2012218251A - Liquid jet head, and liquid jet apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid jet head and a liquid jet apparatus which materialize compaction and high resolution.SOLUTION: The liquid jet head includes a channel formation substrate 10 provided with a plurality of arrays of pressure generation chambers 12 and a plurality of arrays of pressure generation elements 300 formed on one side of a channel formation substrate. Terminals 91 for individual electrodes, which are connected with individual electrodes so formed as to correspond to respective pressure generation elements in the arrays arranged on both sides in a direction intersecting the array direction of pressure generation chambers of the channel formation substrate, are provided in the center of the array. On the terminals for individual electrodes, a drive circuit 200 for connecting an external electric signal electrically with individual electrodes is mounted, and furthermore a wiring 95 for common power supply arranged on the underside to overlap the drive circuit and connected with a common electrode becoming an electrode common to the pressure generation elements and a mounting part 410 for connection with a flexible tape substrate 400 consisting of a terminal for supplying an electric signal from the drive circuit to the outside, and a terminal of the wiring for common power supply are provided.

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that eject liquid from nozzles, and more particularly to an ink jet recording head and an ink jet recording apparatus that eject ink as liquid.

  A typical example of a liquid ejecting head that ejects droplets is an ink jet recording head that ejects ink droplets. As the ink jet recording head, for example, a flow path forming substrate in which a pressure generating chamber communicating with a nozzle and a communicating portion communicating with the pressure generating chamber are formed, and formed on one side of the flow path forming substrate. A substrate including a piezoelectric element and a protective substrate having a piezoelectric element holding portion for holding the piezoelectric element bonded to the surface of the flow path forming substrate on the piezoelectric element side is known. In addition, the drive circuit and the piezoelectric element are connected by a wire bonding method with a connection wiring made of a conductive wire via a lead electrode drawn from one electrode of the piezoelectric element.

  Some protective substrates protect two rows of piezoelectric elements arranged corresponding to two opposite rows of pressure generating chambers, and the connection wiring is inserted into the central portion of this type of protective substrate. A through hole is formed. In such an ink jet recording head, the lead electrode and connection wiring are connected at the through hole portion (see, for example, Patent Document 1).

  Further, in order to reduce manufacturing costs and to ensure connection reliability, a device in which an IC chip is directly mounted on a flow path forming substrate has been proposed (see, for example, Patent Document 2).

JP 2004-148813 A JP 2007-332237 A

  However, in Patent Document 2, the common lead electrode connected to the common electrode is connected to the IC chip together with the lead electrode connected to the individual electrode. Therefore, there is a problem that it is difficult to cope with high resolution. That is, in order to increase the resolution, there is a problem that the terminals may be short-circuited because the common lead electrode is drawn into the space between the lead electrodes for the individual electrodes.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head and a liquid ejecting apparatus that achieve downsizing and higher resolution.

An aspect of the present invention that achieves the above object includes a flow path forming substrate provided with a plurality of rows of a plurality of pressure generation chambers communicating with a nozzle that discharges liquid, and formed on one surface side of the flow path forming substrate. A plurality of rows of pressure generating elements for generating a pressure change in the liquid in the pressure generating chamber, and generating the pressure on both sides of the flow path forming substrate in a direction intersecting with the direction in which the rows of the pressure generating chambers are juxtaposed. A row of chambers and a row of pressure generating elements are arranged, and individual electrode terminals connected to individual electrodes formed corresponding to the pressure generating elements of the rows arranged on both sides, An electric signal from the outside is provided on the individual electrode terminal and provided on a central portion in a direction intersecting with the juxtaposed direction of the columns. The drive circuit to be connected to A common electrode wiring line disposed on the lower side so as to overlap the drive circuit in the liquid discharge direction and connected to a common electrode serving as a common electrode for the pressure generating elements in the columns disposed on both sides; And a mounting portion to which a flexible tape substrate composed of a terminal for supplying an electric signal from the outside to the driving circuit and a terminal of the common electrode wiring is connected. Located in the liquid jet head.
In such an embodiment, a drive circuit for driving the pressure generating elements on both sides is mounted in the space between the rows of pressure generating elements, and only the terminals for individual electrodes are directly connected to the drive circuit, and the common electrode wiring is provided. Since a mounting portion provided in a space below the driving circuit and having a terminal for inputting an external signal into the driving circuit and the common electrode wiring is separately provided, miniaturization and high resolution can be realized.

  Here, in one row of the pressure generating chambers, the nozzle rows are arranged in a zigzag manner so that the positions in the direction intersecting the juxtaposed direction of the pressure generating chambers are different, and the row of the nozzles is a plurality of rows. Also good. According to this, substantially two rows of nozzles can be arranged on one side of the drive circuit.

  Further, it is preferable that the width of the common electrode wiring in the region overlapping with the driving circuit is larger than the width of the wiring other than the overlapping region. According to this, the resistance of the common electrode wiring can be further reduced, and the voltage drop problem can be solved.

  Moreover, it is preferable that the drive circuit is placed on the common electrode wiring in a region overlapping with the drive circuit. According to this, the drive circuit is supported by the common electrode wiring and is stably mounted.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.
In such an aspect, an apparatus capable of realizing the miniaturization and high resolution of the head can be provided.

FIG. 2 is an exploded perspective view of a recording head according to Embodiment 1 of the invention. FIG. 3 is a plan view of the recording head according to the first embodiment of the invention. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment of the invention. 1 is a schematic view showing an ink jet recording apparatus according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view of an ink jet recording head that is an example of a liquid jet head according to Embodiment 1 of the present invention, and FIG. 2 is a plan view of a main part of a flow path forming substrate of the ink jet recording head. 3 is a cross-sectional view taken along the line AA ′ of FIG. As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate having a plane orientation (110) in this embodiment, and an elastic film 50 made of silicon dioxide is formed on one surface thereof.

  The flow path forming substrate 10 is provided with two rows in which a plurality of pressure generating chambers 12 partitioned by a partition wall 11 are arranged in parallel. In addition, a communication portion 13 is formed in a region outside the direction intersecting the juxtaposed direction of the pressure generation chambers 12 in each row, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. The ink supply path 14 and the communication path 15 communicate with each other. The communication portion 13 communicates with a reservoir portion 31 of the protective substrate 30 described later and constitutes a part of the reservoir 100 that becomes a common ink chamber for each row of the pressure generating chambers 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13. In this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. Further, each communication passage 15 is formed by extending the partition walls 11 on both sides in the width direction of the pressure generating chamber 12 to the communication portion 13 side to partition the space between the ink supply path 14 and the communication portion 13. Yes. That is, the flow path forming substrate 10 has an ink supply path 14 having a cross-sectional area smaller than the cross-sectional area of the pressure generating chamber 12 in the width direction, and communicates with the ink supply path 14 and disconnects the ink supply path 14 in the width direction. A communication passage 15 having a cross-sectional area larger than the area is provided by being partitioned by a plurality of partition walls 11.

  Further, on the nozzle surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle 21 communicating with the vicinity of the end portion of each pressure generating chamber 12 opposite to the ink supply path 14 is provided with an adhesive or It is fixed by a heat welding film or the like. In this embodiment, since two rows in which the pressure generating chambers 12 are arranged in parallel are provided on the flow path forming substrate 10, two nozzle rows in which the nozzles 21 are arranged in parallel are provided in one ink jet recording head I. It has been. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, or stainless steel.

  On the other hand, the elastic film 50 is formed on the side opposite to the nozzle surface of the flow path forming substrate 10 as described above, and the insulator film 55 is formed on the elastic film 50. Further, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated on the insulator film 55 to constitute the piezoelectric element 300 that is the pressure generating element of the present embodiment. Yes. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In addition, here, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the first electrode 60 is a common electrode of the piezoelectric element 300, and the second electrode 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. Also, here, the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, and the first electrode 60 function as a diaphragm. However, the present invention is not limited to this. For example, the elastic film 50 and the insulator film 55 are provided. Instead, only the first electrode 60 may act as a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

  In addition, each second electrode 80 that is an individual electrode of the piezoelectric element 300 is connected to a lead electrode 90 made of, for example, gold (Au) or the like extending to the insulator film 55. The lead electrode 90 has one end connected to the second electrode 80, the other end extending between the rows where the piezoelectric elements 300 are arranged in parallel, and the other end serving as a terminal portion 91. As will be described later, the drive circuit 200 is mounted.

  Furthermore, the first electrode 60 that is a common electrode is provided continuously in the direction in which the piezoelectric elements 300 are arranged in parallel, and extends to both outer sides in the direction in which the pressure generating chambers 12 are arranged in parallel. The first electrodes 60 extending outward in the juxtaposed direction of the rows of the pressure generating chambers 12 are connected by a common electrode wiring 95 made of gold (Au) or the like, and further provided on both sides in the juxtaposed direction. The common electrode wiring 95 is connected between the columns by a common electrode wiring 96 arranged in a region overlapping the mounting region of the drive circuit 200. Further, a region of the common electrode wiring 96 that overlaps the mounting region of the drive circuit 200 is a wide portion 97 to reduce the electric resistance.

  In addition, a mounting portion 410 for connecting a flexible tape substrate 400 such as an FPC for introducing an electric signal from the outside to the drive circuit 200 is provided. The mounting portion 410 is provided with a terminal portion 98 of the common electrode wiring 96 along with a plurality of terminals 411 connected to the drive circuit 200.

  On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, that is, on the first electrode 60, the insulator film 55, and the lead electrode 90, there is a reservoir portion 31 that constitutes at least a part of the reservoir 100. The protective substrate 30 is bonded via an adhesive 35. In the present embodiment, the reservoir portion 31 is formed across the protective substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and as described above, the communication portion 13 of the flow path forming substrate 10 is formed. The reservoir 100 is configured as a common ink chamber for the pressure generating chambers 12. In the present embodiment, the flow path forming substrate 10 is provided with the communication portion 13 that becomes the reservoir 100. However, the present invention is not particularly limited thereto. For example, the communication portion 13 of the flow path forming substrate 10 is connected to the pressure generating chamber 12. It is also possible to divide each into a plurality and to use only the reservoir 31 as a reservoir. Further, for example, only the pressure generation chamber 12 is provided on the flow path forming substrate 10, and a reservoir and a member interposed between the flow path forming substrate 10 and the protective substrate 30 (for example, the elastic film 50, the insulator film 55, etc.) An ink supply path 14 that communicates with each pressure generating chamber 12 may be provided.

  In a region of the protective substrate 30 facing the piezoelectric element 300, a piezoelectric element holding portion 32, which is a holding portion having a space that does not hinder the movement of the piezoelectric element 300, is provided. The piezoelectric element holding part 32 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed. In this embodiment, since two rows in which the piezoelectric elements 300 are arranged in parallel are provided, the piezoelectric element holding portion 32 is provided corresponding to each row in which the piezoelectric elements 300 are arranged in parallel. . That is, the protective substrate 30 is provided with two rows in the row direction in which rows intersecting the row direction of the rows of the piezoelectric elements 300 in which the piezoelectric element holding portions 32 are juxtaposed are arranged.

  As such a protective substrate 30, it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, a ceramic material, or the like. In this embodiment, the silicon single crystal substrate made of the same material as the flow path forming substrate 10 is used. The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The through hole 33 is provided between the two piezoelectric element holding portions 32. The vicinity of the end portion of the lead electrode 90 drawn out from each piezoelectric element 300 is provided so as to be exposed in the through hole 33, and the end portion serves as a terminal portion 91 on which the drive circuit 200 is mounted as described later. ing.

  Furthermore, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film), and one surface of the reservoir portion 31 is sealed by the sealing film 41. The fixed plate 42 is formed of a hard material such as metal (for example, stainless steel (SUS)). Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  Further, a head case 110 that is a holding member is provided on the compliance substrate 40. The head case 110 is provided with an ink introduction path 111 that communicates with the ink introduction port 44 and supplies ink from ink storage means such as a cartridge to the reservoir 100. Further, the head case 110 is formed with a recess 112 in a region facing the opening 43 so that the deflection of the opening 43 is appropriately performed. Further, the head case 110 is provided with a through portion 113 communicating with the through hole 33 provided in the protective substrate 30. In addition, as a material of such a head case 110, metal materials, such as stainless steel, are suitable, for example.

  Here, the drive circuit 200 is mounted on the terminal portion 91 of the lead electrode 90 extending in the opening 43 and the through portion 113. That is, the drive circuit 200 which is a drive IC chip is mounted so that the terminal 201 and the terminal portion 91 of the lead electrode 90 are securely connected by a metal-metal bond or the like. That is, only the second electrode 80 that is an individual electrode is connected to the drive circuit 200.

  On the other hand, the common electrode wiring 96 connected to the first electrode 60 which is a common electrode is disposed in a region overlapping the mounting region of the drive circuit 200. In the present embodiment, the same layer 61 that is patterned simultaneously with the first electrode 60 is provided under the common electrode wiring 96, and the drive circuit 200 is placed on the common electrode wiring 96. . That is, the drive circuit 200 is mounted on the wide portion 97 of the common electrode wiring 96 (electrically unconnected) and mounted on the terminal portion 91 in a stable state. In addition, the external signal input terminal of the mounted drive circuit 200 is connected to the terminal 411 of the mounting unit 410, and an electric signal from the outside is connected via the tape substrate 400 connected to the mounting unit 410 including the terminal 411. Is introduced into the drive circuit 200.

  As described above, in this embodiment, the drive circuit 200 is mounted in the space between the two rows of the piezoelectric elements 300, and the lead electrode 90 connected to the second electrode 80 that is an individual electrode is provided in the drive circuit 200. The first electrode 60, which is a common electrode, is connected to the tape substrate 400 via the terminal portion 98 via the common electrode wirings 95 and 96, so that miniaturization and high density are achieved. In addition, it is possible to reliably connect the drive circuit 200 and the terminal portion 91 at that time. In addition, since the individual electrodes and the common electrode are drawn out in different directions, there is no possibility of short circuit.

  In the ink jet recording head described above, ink is taken in from an ink introduction port connected to an external ink storage means (not shown), the interior from the reservoir 100 to the nozzle 21 is filled with ink, and then recording from the drive circuit 200 is performed. In accordance with the signal, a voltage is applied between each of the first electrode 60 and the second electrode 80 corresponding to the pressure generation chamber 12 to bend the elastic film 50, the insulator film 55, the first electrode 60, and the piezoelectric layer 70. By deforming, the pressure in each pressure generating chamber 12 increases and ink droplets are ejected from the nozzle 21.

  Furthermore, according to the present embodiment, since the drive circuit 200 is directly connected to the terminal portion of the lead electrode 90, manufacturing is easier than by the wire bonding method, and the drive circuit 200 is directly connected to the lead electrode 90. Therefore, even if the piezoelectric elements 300 are arranged at a high density, a high density can be easily achieved without causing a connection failure between the lead electrode 90 and the drive circuit 200.

(Other embodiments)
In the first embodiment described above, two rows in which the pressure generating chambers 12 are arranged in parallel on the flow path forming substrate 10 are provided, but the number of rows in this case is not particularly limited. If there are a plurality of columns, there may be three or more columns. In the case of a plurality of rows, at least two rows may be provided so as to face each other. Further, in one row of the pressure generating chambers 12 of the above-described embodiment, the adjacent pressure generating chambers 12 are arranged in a staggered manner so that the positions in the direction intersecting the juxtaposed direction are different, and there are a plurality of rows of nozzles 21. It may be arranged in a row. Further, it is not necessary to limit the material and structure of the flow channel to the above embodiment.

  Further, in the first embodiment described above, the actuator device having the thin film type piezoelectric element 300 is described as the pressure generating element for causing the pressure change in the pressure generating chamber 12, but the invention is not particularly limited thereto. It is possible to use a thick film type actuator device formed by a method such as attaching a green sheet or a longitudinal vibration type actuator device in which piezoelectric materials and electrode forming materials are alternately stacked to expand and contract in the axial direction. it can. In addition, as a pressure generating element, a heating element is arranged in the pressure generating chamber, and droplets are ejected from the nozzle by bubbles generated by heat generation of the heating element, or static electricity is generated between the diaphragm and the electrode. A so-called electrostatic actuator that deforms the diaphragm by electrostatic force and discharges droplets from the nozzle can be used.

  The ink jet recording head according to the above-described embodiment constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 4 is a schematic view showing an example of the ink jet recording apparatus. As shown in the drawing, the recording head units 1A and 1B having the ink jet recording head I according to the above-described embodiment are provided with cartridges 2A and 2B constituting the ink supply means in a detachable manner, and the recording head units 1A and 1B. Is mounted on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head of the present invention. However, the basic configuration of the liquid ejecting head is not limited to the above. The present invention covers a wide range of liquid ejecting heads, and can naturally be applied to those ejecting liquids other than ink. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  I ink jet recording head (liquid ejecting head), 10 flow path forming substrate, 12 pressure generating chamber, 13 ink supply path, 14 communication path, 21 nozzle, 30 protective substrate, 32 piezoelectric element holding portion, 33 through hole, 60th 1 electrode, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 95, 96 common electrode wiring, 100 reservoir, 110 head case (holding member), 113 penetrating portion, 200 drive circuit, 300 piezoelectric element (pressure generation) Element), 400 tape substrate, 410 mounting portion

Claims (5)

A flow path forming substrate provided with a plurality of rows of a plurality of pressure generating chambers communicating with nozzles for discharging liquid;
A plurality of rows of pressure generating elements that are formed on one surface side of the flow path forming substrate and generate a pressure change in the liquid in the pressure generating chamber;
The rows of the pressure generating chambers and the rows of the pressure generating elements are respectively arranged on both sides in the direction intersecting the juxtaposed direction of the rows of the pressure generating chambers of the flow path forming substrate.
A terminal for an individual electrode connected to an individual electrode formed corresponding to each of the pressure generating elements in the row arranged on both sides is provided in a central portion in a direction intersecting the juxtaposing direction of the row. ,
A drive circuit for electrically connecting an external electric signal to the individual electrodes of the pressure generating elements in a row arranged on both sides is mounted on the terminals for the individual electrodes,
A common electrode wiring that is arranged on the lower side so as to overlap the drive circuit in the liquid ejection direction, and is connected to a common electrode that is a common electrode for the pressure generating elements in the rows arranged on both sides;
A mounting portion to which a flexible tape substrate composed of a terminal for supplying an electric signal from the outside to the drive circuit and a terminal of the common electrode wiring is connected;
A liquid ejecting head characterized by comprising: The liquid ejecting head according to claim 1,
In one row of the pressure generating chambers, the nozzle rows are arranged in a staggered manner so that positions in a direction intersecting with the direction in which the pressure generating chambers are arranged are different, and the nozzle rows are a plurality of rows. Liquid ejecting head. The liquid ejecting head according to claim 1,
The liquid ejecting head according to claim 1, wherein a width of the common electrode wiring in a region overlapping with the driving circuit is larger than a width of a wiring other than the overlapping region. The liquid ejecting head according to claim 1,
The liquid ejecting head, wherein the driving circuit is placed on the common electrode wiring in a region overlapping with the driving circuit.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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