JP2019111733A - Inkjet head, inkjet recording device and manufacturing method of inkjet head - Google Patents

Abstract

To provide an inkjet head that can suppress occurrence of ink leakage in a layer of an adhesive agent, an inkjet recording device and a manufacturing method of the inkjet head.SOLUTION: An inkjet head for discharging ink from a nozzle comprises: a pressure chamber substrate (13) which has a base material (130) made of a ceramic piezoelectric body, and in which a pressure chamber that varies pressure of ink stored therein according to deformation is provided in the base material; an intermediate substrate (12) tightly fixed to a prescribed face formed by the base material among surfaces of the pressure chamber substrate and provided with an ink flow path; a protective film (14) provided on a surface at the opposite side of the pressure chamber substrate side of the intermediate substrate; and a nozzle substrate (11) made to adhere to a surface at the opposite side of the intermediate substrate side of the protective film via an adhesive agent and provided with a nozzle. Surface roughness of a front surface of the surface provided with the protective film of the intermediate substrate is smaller than a surface of the prescribed face of the pressure chamber substrate.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an inkjet head, an inkjet recording apparatus, and a method of manufacturing an inkjet head.

  2. Description of the Related Art Conventionally, there is an inkjet recording apparatus that ejects ink from nozzles provided in an inkjet head to form an image or the like. The ink jet head of the ink jet recording apparatus is bonded to a pressure chamber substrate provided with a pressure chamber for changing the pressure of the ink stored therein according to the deformation, and the pressure chamber substrate via an adhesive, to the pressure chamber. And a nozzle substrate provided with a communicating nozzle. In such an inkjet head, the ink can be ejected from the nozzle by changing the pressure of the ink in the pressure chamber.

  As the pressure chamber substrate, there is known one in which a pressure chamber is provided in a substrate made of ceramic piezoelectric material and an electrode is provided on the inner wall surface of the pressure chamber. In such a pressure chamber substrate, the pressure of the ink in the pressure chamber can be varied by applying a voltage to the wall surface of the pressure chamber through the electrode to deform the wall surface. In addition, there is a technology for suppressing the occurrence of a defect in which the substrate and the electrode are corroded by the ink by forming a protective film on the surface of the substrate and the inner wall surface of the pressure chamber (for example, Patent Document 1). When a pressure chamber substrate having such a protective film is used for an inkjet head, the nozzle substrate is adhered to the above-described protective film provided on the surface of the base material.

Patent No. 5936986 gazette

  However, a substrate made of ceramic piezoelectric material has irregularities on the surface, and is formed when a protective film is formed on the surface by a commonly used thin film forming method such as vapor deposition or CVD (Chemical Vapor Deposition). The surface of the protective film is likely to be in a state in which the unevenness of the step is larger than the unevenness of the surface of the base material. When the nozzle substrate is adhered to the protective film having such irregularities on the surface through an adhesive, voids of the adhesive are likely to be generated around foreign substances mixed between the protective film and the nozzle substrate. If the adhesive has a void, there is a problem that the ink may leak from the ink supply path to the nozzle to the void. Such a leak of ink reduces the amount of ink supplied to the nozzles or causes an unintended ink flow path between the nozzles, causing an abnormality in the ink supply to the nozzles and causing an ink discharge failure. It leads to the occurrence.

  An object of the present invention is to provide an ink jet head, an ink jet recording apparatus, and a method of manufacturing the ink jet head which can suppress the occurrence of ink leakage in the adhesive layer.

In order to achieve the above object, the invention of an ink jet head according to claim 1 is:
An inkjet head that ejects ink from a nozzle,
A pressure chamber substrate having a base made of ceramic piezoelectric material and provided with a pressure chamber for changing the pressure of the ink stored therein according to the deformation;
An intermediate substrate fixed to a predetermined surface of the surface of the pressure chamber substrate and made by the base material and provided with an ink flow path communicating with the pressure chamber;
A protective film provided on the surface of the intermediate substrate opposite to the pressure chamber substrate side;
A nozzle substrate provided with the nozzle which is adhered to the surface of the protective film opposite to the intermediate substrate via an adhesive and which communicates with the pressure chamber through the ink flow path;
Equipped with
The surface of the surface of the intermediate substrate on which the protective film is provided has a smaller surface roughness than the surface of the predetermined surface of the pressure chamber substrate.

The invention according to claim 2 is the inkjet head according to claim 1 in which
The intermediate substrate is made of Si, metal or glass.

The invention according to claim 3 is the inkjet head according to claim 1 or 2, wherein
The protective film is an inorganic oxide or inorganic nitride containing at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si, or polyparaxylylene.

The invention according to claim 4 is the ink jet head according to any one of claims 1 to 3.
Equipped with an ink outlet for discharging ink to the outside,
The pressure chamber substrate is provided with a first discharge flow passage communicating with the ink discharge port,
The ink flow path has a second discharge flow path for guiding a part of the ink supplied from the pressure chamber to the ink flow path to the first discharge flow path of the pressure chamber substrate.

The invention according to claim 5 is the ink jet head according to any one of claims 1 to 4 in which
The surface of the surface on which the protective film of the intermediate substrate is provided has an absolute value of the height from the plane along the surface of the object to the surface of the surface of the predetermined surface of the pressure chamber substrate. Arithmetic mean roughness Sa representing values averaged over a range of dimensions is small.

In order to achieve the above object, the invention of an inkjet recording apparatus according to claim 6 is:
The inkjet head according to any one of claims 1 to 5 is provided.

In order to achieve the above object, the invention of the method of manufacturing an ink jet head according to claim 7 is:
A method of manufacturing an ink jet head for discharging ink from a nozzle, comprising:
Forming a pressure chamber for changing the pressure of the ink stored therein according to the deformation on a substrate made of ceramic piezoelectric material, and manufacturing a pressure chamber substrate having the substrate;
Fixing a predetermined intermediate substrate provided with an ink flow passage to a predetermined surface of the pressure chamber substrate made by the base material so that the ink flow passage communicates with the pressure chamber;
Forming a protective film on the surface of the intermediate substrate opposite to the pressure chamber substrate side;
The nozzle substrate provided with the nozzle is adhered to the surface of the protective film opposite to the intermediate substrate via an adhesive so that the nozzle communicates with the pressure chamber via the ink flow path. The process to
Including
The surface of the surface of the intermediate substrate on which the protective film is provided has a smaller surface roughness than the surface of the predetermined surface of the pressure chamber substrate.

  According to the present invention, there is an effect that the occurrence of ink leakage in the adhesive layer can be suppressed.

FIG. 1 is a view showing a schematic configuration of an inkjet recording apparatus. It is a perspective view which shows the internal structure of a head unit. It is an exploded perspective view of the principal part of an ink jet head. It is an enlarged plan view of a pressure chamber substrate. It is an expanded sectional view of a head chip and a wiring board. It is a figure explaining the effect show | played by the structure of the inkjet head of this embodiment. It is the photograph which image | photographed the surface of the said protective film at the time of forming a protective film on the surface of a silicon substrate, the surface of a PZT board | substrate, and these each board | substrates, respectively. It is a schematic cross section explaining the manufacturing method of an inkjet head.

  Hereinafter, an embodiment according to an inkjet head, an inkjet recording apparatus, and a method of manufacturing an inkjet head of the present invention will be described based on the drawings.

FIG. 1 is a view showing a schematic configuration of an inkjet recording apparatus 100 according to an embodiment of the present invention.
The inkjet recording apparatus 100 includes a transport unit 80, a head unit 90, and the like.

  The transport unit 80 includes a ring-shaped transport belt 83 whose inside is supported by two transport rollers 81 and 82 that rotate around a rotation axis extending in the X direction in FIG. 1. With the recording medium M placed on the conveyance surface of the conveyance belt 83, the conveyance unit 80 rotates the conveyance roller 81 in accordance with the operation of the conveyance motor (not shown) and performs circumferential movement of the conveyance belt 83 to perform recording. The medium M is transported in the moving direction of the transport belt 83 (transport direction; Y direction in FIG. 1).

  The recording medium M can be a sheet that has been cut to size. The recording medium M is supplied onto the conveyance belt 83 by a paper feeding device (not shown), and the ink is discharged from the head unit 90 to record an image, and then the recording medium M is discharged from the conveyance belt 83 to a predetermined paper discharge unit. As the recording medium M, roll paper may be used. Further, as the recording medium M, in addition to paper such as plain paper and coated paper, various media such as fabric or sheet-like resin, which can fix the ink landed on the surface can be used.

  The head unit 90 discharges the ink to the recording medium M transported by the transport unit 80 at an appropriate timing based on the image data to record an image. In the inkjet recording apparatus 100 according to this embodiment, four head units 90 respectively corresponding to four color inks of yellow (Y), magenta (M), cyan (C), and black (K) are in the conveyance direction of the recording medium M. From the upstream side, they are arranged in the order of Y, M, C, and K in a predetermined interval. The number of head units 90 may be three or less or five or more.

FIG. 2 is a perspective view showing an internal configuration of the head unit 90. As shown in FIG.
The head unit 90 has a holding substrate 91 and a plurality of (here, six) inkjet heads 1 fixed to the holding substrate 91 by the fixing member 92 in a state of being bonded to the through holes provided in the holding substrate 91. . The inkjet head 1 has a configuration in which main components are accommodated inside the exterior member 40. The ink jet head 1 is fixed to the holding substrate 91 in a state where the nozzle opening surface provided with the opening of the nozzle is exposed downward from the through hole of the holding substrate 91.

In the inkjet head 1, the plurality of nozzles 111 (FIG. 3) for ejecting the ink are arranged in a direction crossing the conveyance direction of the recording medium M (in the present embodiment, in the width direction orthogonal to the conveyance direction, that is, the X direction) . Further, in each inkjet head 1, two rows of nozzles formed of nozzles arranged one-dimensionally in the X direction are provided, and the plurality of nozzle rows are provided in a positional relationship in which the positions of the nozzles are mutually offset in the X direction. ing. The number of nozzle rows is not limited to two, and may be one or three or more.
Further, the ink jet head 1 is provided with an inlet 41 into which the ink supplied into the ink jet head 1 flows, and an outlet 42 (ink discharge port) through which the ink discharged from the ink jet head 1 flows out.

  The six inkjet heads 1 in each head unit 90 are staggered such that the arrangement range of the nozzles in the X direction covers the width in the X direction of the area on which the image can be recorded on the recording medium M on the transport belt 83. They are arranged in a grid. As described above, in the inkjet recording apparatus 100 in which the inkjet head 1 is disposed, the recording medium M is conveyed by discharging the ink from the inkjet head 1 at an appropriate timing according to the image data in a state where the head unit 90 is fixed. Images can be recorded on top. That is, the inkjet recording apparatus 100 records an image by a single pass method.

Next, the configuration of the inkjet head 1 will be described.
FIG. 3 is an exploded perspective view of the main part of the inkjet head 1.
In FIG. 3, among the constituent members of the inkjet head 1, the main constituent members accommodated inside the exterior member 40 are shown. Specifically, in FIG. 3, the head chip 10 having the nozzle substrate 11 provided with the nozzles 111, the wiring substrate 20 fixed to the head chip 10, and the FPC 30 electrically connected to the wiring substrate 20 (Flexible Printed Circuit) is shown. In FIG. 3, each member is drawn such that the nozzle opening surface of the nozzle substrate 11 is on the upper side, that is, upside down with respect to FIG. 2. Hereinafter, the surface on the -Z direction side of each substrate is also referred to as the upper surface, and the surface on the + Z direction side is also referred to as the lower surface.

  The head chip 10 is a substantially square columnar member elongated in the X direction, and the nozzle substrate 11 and a flow path substrate 12 (intermediate substrate) provided with an ink flow path 121 communicating with the nozzles 111, and an ink flow path The pressure chamber substrate 13 provided with a pressure chamber 131 and the like communicating with the nozzle 111 via the portion 121 is stacked.

Among them, the pressure chamber substrate 13 has a base material 130 made of a ceramic piezoelectric material (a member that deforms in response to the application of a voltage). Specifically, the pressure chamber substrate 13 processes the base material 130 made of a rectangular parallelepiped plate-like piezoelectric material to form a through hole or a recess, thereby forming the pressure chamber 131 and the common ink discharge flow path in the base material 130. 132 (first discharge flow path) is provided, and the substrate is obtained by forming metal electrodes (drive electrode 133 and connection electrode 135 (FIG. 4)) on the wall surface of the pressure chamber 131 and the like.
Here, the ceramic is a material obtained by sintering an inorganic substance. Examples of piezoelectrics made of such ceramics include PZT (lead zirconate titanate), lithium niobate, barium titanate, lead titanate, and lead metaniobate. In the pressure chamber substrate 13 of the present embodiment, a substrate 130 made of PZT is used.

The pressure chambers 131 of the pressure chamber substrate 13 are through holes respectively provided at positions overlapping with the nozzles 111 when viewed in the Z direction in the base material 130, and the cross section along the XY plane has a long rectangle in the Y direction There is no. In the pressure chamber substrate 13 of the present embodiment, the plurality of pressure chambers 131 are arranged in two rows along the X direction. Further, the positions in the X direction of the two rows formed by the pressure chambers 131 are shifted so that the positions in the X direction of the pressure chambers 131 are different from each other. That is, in the pressure chamber substrate 13, the plurality of pressure chambers 131 are arranged in a staggered pattern.
Ink is supplied to each pressure chamber 131 via an ink supply port 201 provided in the wiring substrate 20. Each pressure chamber 131 is in communication with the nozzle 111 via the ink flow path 121 of the flow path substrate 12.

FIG. 4 is an enlarged plan view of the pressure chamber substrate 13. FIG. 4 is a plan view of a portion of the pressure chamber substrate 13 in the vicinity of the pressure chamber 131 as viewed from the lower side of FIG. 3 (from the + Z direction side).
As shown in FIG. 4, each pressure chamber 131 is partitioned by the partition 134 of the piezoelectric body between the pressure chambers 131 adjacent in the X direction. A metal drive electrode 133 is provided on the inner wall surface of the partition 134 of each pressure chamber 131. A metal connection electrode 135 electrically connected to the drive electrode 133 is provided in the vicinity of the opening of the pressure chamber 131 in the −Y direction on the surface of the base 130. The connection electrode 135 is electrically connected to an external drive circuit via the wiring 203 of the wiring substrate 20 and the wiring 31 of the FPC 30 shown in FIG.

In the pressure chamber substrate 13, the pressure of the ink in the pressure chamber 131 is fluctuated as the partition 134 repeats the shear mode displacement according to the drive signal applied to the drive electrode 133 via the connection electrode 135. The ink in the pressure chamber 131 is discharged from the nozzle 111 via the ink flow path 121 according to the fluctuation of the pressure.
Note that, instead of the pressure chamber 131, an air chamber to which ink is not supplied may be provided at the formation position of the pressure chambers 131 every other one in the X direction in FIG. With such a configuration, when the partition 134 adjacent to one pressure chamber 131 is deformed, the other pressure chamber 131 can be prevented from being affected by the deformation.

  As shown in FIG. 3, in the pressure chamber substrate 13, a part of the ink which is not discharged from the nozzles 111 among the ink supplied from the pressure chamber 131 to the ink flow path 121 of the flow path substrate 12 returns in common. An ink discharge flow path 132 is provided. The common ink discharge flow paths 132 are provided one by one at positions sandwiching the plurality of pressure chambers 131 in the Y direction. The common ink discharge flow path 132 is a groove-like horizontal common discharge flow path 132a extending in the X direction along the surface of the base material 130 on the flow path substrate 12 side near the end in the Y direction, And a vertical common discharge flow path 132b connected to the horizontal common discharge flow path 132a at the end in the + X direction of 132a and penetrating the base material 130 in the Z direction. The ink returned from the ink flow path 121 of the flow path substrate 12 to the horizontal common discharge flow path 132a passes through the vertical common discharge flow path 132b and the discharge holes 202 provided in the wiring substrate 20 and the ink jet head 1 It is discharged to the outside.

  The flow path substrate 12 is a rectangular parallelepiped plate-like member having substantially the same size as the pressure chamber substrate 13 in a plan view. The flow path substrate 12 is adhered (adhered) to the upper surface (predetermined surface) of the surface of the pressure chamber substrate 13 formed by the base 130 through an adhesive. The flow path substrate 12 of the present embodiment is made of a silicon (Si) substrate. The thickness of the flow path substrate 12 is not particularly limited, but is about several hundred μm.

The ink flow path 121 provided in the flow path substrate 12 separates from the through flow path 122 which penetrates the flow path substrate 12 at a position overlapping with the formation position of the pressure chamber 131 when viewed from the Z direction, And the ink discharge flow path 123 (second discharge flow path).
A cross-sectional shape parallel to the X-Y plane of the through flow passage 122 is a rectangle substantially the same as the cross-sectional shape of the pressure chamber 131. In the through flow passage 122, an opening on the pressure chamber substrate 13 side is connected to the pressure chamber 131, and an opening on the nozzle substrate 11 side is connected to the nozzle 111.
The individual ink discharge channel 123 is a groove-shaped horizontal individual discharge channel 123a extending along the surface of the channel substrate 12 from the opening on the nozzle substrate 11 side of the through channel 122 toward the end in the Y direction, And a vertical individual discharge flow passage 123b provided to penetrate the flow passage substrate 12 from the end of the horizontal individual discharge flow passage 123a. An opening on the pressure chamber substrate 13 side of the vertical individual discharge flow passage 123 b is connected to the horizontal common discharge flow passage 132 a of the common ink discharge flow passage 132. Therefore, the individual ink discharge flow channel 123 guides the ink flowing from the through flow channel 122 into the horizontal individual discharge flow channel 123a to the common ink discharge flow channel 132 via the vertical individual discharge flow channel 123b.

  Thus, the ink in the pressure chamber 131 is not discharged from the nozzle 111 by the individual ink discharge flow passage 123 provided in the flow passage substrate 12 and the common ink discharge flow passage 132 provided in the pressure chamber substrate 13. An ink discharge channel for discharging the ink is formed.

The nozzle substrate 11 is a silicon substrate in which the nozzles 111 which are holes penetrating in the thickness direction (Z direction) are provided in two rows in a staggered arrangement. Each nozzle 111 is provided at a position overlapping with the through flow passage 122 in the ink flow passage 121 of the flow passage substrate 12 when viewed from the Z direction. The planar shape of the nozzle substrate 11 is substantially the same as that of the flow passage substrate 12 and the pressure chamber substrate 13. The thickness of the nozzle substrate 11 is, for example, about several tens of μm to several hundreds of μm.
The inner wall surface of the nozzle 111 may have a tapered shape such that the cross-sectional area perpendicular to the Z direction decreases as it approaches the opening on the ink discharge side. The nozzle substrate 11 may be made of resin such as polyimide or metal.

  The wiring substrate 20 is bonded to the lower surface of the head chip 10 via an adhesive. The wiring substrate 20 is a flat substrate having an area larger than that of the head chip 10 (pressure chamber substrate 13) from the viewpoint of securing a bonding area with the head chip 10. As the wiring substrate 20, for example, a substrate of glass, ceramic, silicon, plastic or the like can be used.

The wiring substrate 20 is provided with a plurality of ink supply ports 201 at positions overlapping with the pressure chambers 131 of the pressure chamber substrate 13 when viewed from the Z direction, and positions overlapping with the pair of vertical common discharge flow paths 132b. A pair of discharge holes 202 are provided in the. Further, on the bonding surface of the wiring substrate 20 with the pressure chamber substrate 13, a plurality of wirings 203 extending in the −Y direction from the end of each of the plurality of ink supply ports 201 toward the end of the wiring substrate 20 is provided. ing.
An ink manifold (common ink chamber) (not shown) is connected to the lower surface of the wiring substrate 20, and the ink is supplied from the ink manifold to the ink supply port 201.

  The head chip 10 (pressure chamber substrate 13) and the wiring substrate 20 are adhered via a conductive adhesive containing conductive particles. Thereby, the connection electrode 135 on the surface of the pressure chamber substrate 13 and the wiring 203 on the wiring substrate 20 are electrically connected via the conductive particles.

  Further, the FPC 30 is connected to an end portion of the wiring substrate 20 at which the wiring 203 is provided, for example, via an ACF (Anisotropic Conductive Film). By this connection, the plurality of wirings 203 of the wiring substrate 20 and the plurality of wirings 31 on the FPC 30 are electrically connected to correspond to each other in a one-to-one manner.

  FIG. 5 is an enlarged sectional view of the head chip 10 and the wiring substrate 20. As shown in FIG. FIG. 5 shows a cross section perpendicular to the Y direction of the head chip 10 and the wiring substrate 20 at positions passing through the plurality of pressure chambers 131.

As shown in FIG. 5, in the ink jet head 1 of the present embodiment, the protective film 14 is provided on the surface of the laminated substrate consisting of the flow path substrate 12, the pressure chamber substrate 13 and the wiring substrate 20 bonded via an adhesive. It is done. Hereinafter, the laminated substrate including the flow path substrate 12, the pressure chamber substrate 13, and the wiring substrate 20 will be referred to as a protective film formation target laminated substrate.
The protective film 14 is formed on the upper surface of the flow path substrate 12, the lower surface of the wiring substrate 20, the inner wall surface of the flow path through which the ink passes inside the protective film formation target laminated substrate, and the side surface of the protective film formation target laminated substrate. It is provided. Here, in the protective film formation target laminated substrate, the flow path through which the ink passes is ink flow path 121 (through flow path 122 and individual ink discharge flow path 123), pressure chamber 131, common ink discharge flow path 132, ink The supply port 201 and the discharge hole 202 are provided.
Further, the nozzle substrate 11 is adhered to the protective film 14 provided on the upper surface of the flow path substrate 12 in the protective film formation target laminated substrate via an adhesive.

The protective film 14 is not particularly limited, but, for example, an organic protective film such as polyparaxylylene, or an inorganic oxide or inorganic material containing at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta, and Si. A protective film made of nitride can be used.
By providing such a protective film 14, the flow path through which the ink passes in the above laminated structure may be corroded by the ink, or the ink attached to the outer surface of the above laminated structure may intrude into the head chip 10 to It is possible to suppress the occurrence of a defect that erodes.

  As described above, by providing the protective film 14 on the upper surface of the flow path substrate 12 and bonding the nozzle substrate 11 to the protective film 14, it is possible to suppress the formation of a void in the layer of the adhesive. Below, this point is explained in detail.

  FIG. 6 is a view for explaining the effects obtained by the configuration of the inkjet head 1 of the present embodiment. FIG. 6A is a schematic cross-sectional view of the head chip 10 of the present embodiment, and shows the region R in FIG. 5 in an enlarged manner. FIG. 6B is a schematic cross-sectional view of a comparative example in which the protective film 14 is formed directly on the upper surface of the pressure chamber substrate 13 without providing the flow channel substrate 12.

As shown in FIG. 6B, the upper surface of the pressure chamber substrate 13 to which the base material 130 made of a ceramic piezoelectric material is exposed has unevenness. Therefore, when the protective film 14 is provided by a commonly used thin film forming method such as vapor deposition or CVD (Chemical Vapor Deposition) with the surface of the pressure chamber substrate 13 as a base, as shown in FIG. The surface of the film 14 tends to have a large unevenness with a step (difference in height) more than the unevenness on the surface of the pressure chamber substrate 13.
Further, when the nozzle substrate 11 is adhered to the protective film 14 of the comparative example having such unevenness through the adhesive 16, the foreign matter A is mixed between the protective film 14 and the nozzle substrate 11 as a foreign matter. Since the adhesive 16 is less likely to wrap around A, voids B of the adhesive 16 are likely to occur around the foreign matter A. As described above, when the adhesive 16 has the space B, the ink may leak from the supply path of the ink to the nozzle 111 to the space B. Such a leak of ink reduces the amount of ink supplied to the nozzles 111 or causes an unintended ink flow path (ink leak path) between the nozzles in the layer of the adhesive 16. An abnormality occurs in the ink supply to 111, leading to an ink ejection failure.

On the other hand, in the head chip 10 of the present embodiment shown in FIG. 6A, the flow path substrate 12 is bonded to the pressure chamber substrate 13 via the adhesive 15, and the protective film is formed on the flow path substrate 12. A nozzle substrate 11 is bonded to the protective film 14 via an adhesive 16.
As shown in FIG. 6A, the upper surface of the flow path substrate 12 made of a silicon substrate does not have asperities or has very few asperities. Therefore, the surface of the upper surface of the flow path substrate 12 is smaller than the surface roughness of the upper surface of the pressure chamber substrate 13. When the arithmetic mean roughness Sa which is one of the surface roughness parameters is used, in the head chip 10 of the present embodiment, the arithmetic mean roughness Sa of the upper surface of the flow path substrate 12 is 0.004 μm, and the pressure chamber is The arithmetic mean roughness Sa of the upper surface of the substrate 13 is 0.336 μm. Here, the arithmetic mean roughness Sa represents a value obtained by averaging the absolute value of the height from the plane along the surface of the object to the surface in a two-dimensional range.

  In the head chip 10 according to the present embodiment shown in FIG. 6A, the protective film 14 is provided on the upper surface of the flow path substrate 12 whose surface roughness is smaller than the surface roughness of the pressure chamber substrate 13 as described above. The surface roughness of the surface of the film 14 is smaller than the surface roughness of the surface of the protective film 14 in FIG.

FIG. 7 is a photograph of the surface of the silicon substrate, the surface of the PZT substrate, and the surface of the protective film when the protective film is formed on each of these substrates.
As shown in the upper left and lower left photographs of FIG. 7, respectively, the surface of the silicon substrate (corresponding to the flow path substrate 12 of this embodiment) and the protective film formed on the silicon substrate (FIG. 6A) No unevenness is observed on the surface of 14).
On the other hand, as shown in the upper right and lower right photographs of FIG. 7, respectively, a protective film provided on the surface of the PZT substrate (corresponding to the base 130 of the pressure chamber substrate 13) or on the PZT substrate (FIG. 6B) A large number of irregularities are observed on the surface of the protective film 14). In particular, it can be seen that asperities on the surface of the protective film provided on the PZT substrate are larger than those on the surface of the PZT substrate.

  As shown in the lower left picture of FIG. 7 and FIG. 6A, the surface of the protective film 14 formed on the flow path substrate 12 made of a silicon substrate in the present embodiment hardly has unevenness. Therefore, when the nozzle substrate 11 is adhered to such a protective film 14 via the adhesive 16, even if the foreign matter A is mixed between the protective film 14 and the nozzle substrate 11, the periphery of the foreign matter A is obtained. The adhesive 16 easily wraps around, and the gap B is less likely to occur. As a result, the ink hardly penetrates into the layer of the adhesive 16, and the occurrence of the ink leakage between the nozzles via the layer of the adhesive 16 can be suppressed.

  6A and 7, the case where the material of the flow path substrate 12 is silicon is described as an example, but the flow path substrate 12 has a surface rougher than the base material 130 made of a piezoelectric material. It is possible to use various materials of small size. For example, a metal such as stainless steel or 42 alloy or glass may be used as the flow path substrate 12.

Next, a method of manufacturing the inkjet head 1 will be described.
FIG. 8 is a schematic cross-sectional view for explaining the method of manufacturing the inkjet head 1.

  In the manufacturing method, first, the flow path substrate 12, the pressure chamber substrate 13, and the wiring substrate 20 are manufactured (Step S1 in FIG. 8). That is, the ink flow path 121 is formed in the silicon substrate to manufacture the flow path substrate 12. Further, the pressure chamber 131 and the common ink discharge flow path 132 are formed in the base material 130 made of a piezoelectric material, and the drive electrode 133 and the connection electrode 135 are formed in the base material 130 to manufacture the pressure chamber substrate 13. Further, the wiring board 20 is manufactured by forming the ink supply port 201, the discharge hole 202 and the wiring 203 on a substrate of a predetermined material.

  Next, the flow path substrate 12, the pressure chamber substrate 13, and the wiring substrate 20 are adhered and laminated via an adhesive, and a protective film formation target laminated substrate is manufactured (Step S2 in FIG. 8).

  Next, the protective film 14 is formed on the surface of the protective film formation target laminated substrate and the inner wall surface of the flow path through which the ink passes inside the protective film formation target laminated substrate by a known vapor deposition method or the like (FIG. 8) Step S3). In this step, for example, when polyparaxylylene is used as the protective film 14, a vapor deposition method can be used. When an inorganic oxide or inorganic nitride containing at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta, and Si is used as the protective film 14, a CVD method, a sputtering method, or the like may be used. it can.

Next, the nozzle substrate 11 manufactured in advance is bonded via an adhesive to the protective film 14 formed on the upper surface of the flow path substrate 12 among the protective film formation target laminated substrates (Step S4 in FIG. 8). .
Thereafter, the FPC 30 is bonded to the wiring substrate 20, and the head chip 10, the wiring substrate 20, and the FPC 30 are incorporated into the exterior member 40 together with the other components, whereby the ink jet head 1 is completed.

As described above, the inkjet head 1 according to the present embodiment is the inkjet head 1 that discharges the ink from the nozzle 111 and includes the base material 130 made of a ceramic piezoelectric material, and is internally stored according to the deformation. The pressure chamber 131 for changing the pressure of the ink is fixed to the pressure chamber substrate 13 provided on the base 130 and a predetermined surface of the pressure chamber substrate 13 made by the substrate 130, and the pressure chamber 131 is fixed to the pressure chamber 131. The flow path substrate 12 provided with the ink flow path 121 to be communicated, the protective film 14 provided on the surface of the flow path substrate 12 opposite to the pressure chamber substrate 13 side, and the flow path substrate 12 of the protective film 14 And a nozzle substrate 11 provided with a nozzle 111 communicating with the pressure chamber 131 via the ink flow path 121 and adhered to the surface opposite to the side via the adhesive 16; Surface of the surface Mamorumaku 14 is provided, than the surface of the predetermined surface of the pressure chamber substrate 13, a small surface roughness.
According to such a configuration, as compared with the configuration in which the protective film 14 is formed directly on the base material 130 made of a piezoelectric material, the level difference of the unevenness on the surface of the protective film 14 can be reduced. By adhering the nozzle substrate 11 to the surface of the protective film 14 via the adhesive 16, even if foreign matter is mixed between the protective film 14 and the nozzle substrate 11, adhesion is made around the foreign matter. The agent 16 easily wraps around, making it difficult for voids to form in the adhesive 16. This makes it difficult for the ink to penetrate into the layer of the adhesive 16, and the occurrence of ink leakage in the layer of the adhesive 16 can be suppressed. As a result, the amount of ink supplied to the nozzles 111 may be reduced, or an unintended ink flow path between the nozzles may be generated in the layer of the adhesive 16, and the desired ink supply to the nozzles 111 may not be performed. Occurrence can be suppressed.

  Further, by using a substrate made of Si, metal or glass as the flow path substrate 12, the surface roughness of the surface of the flow path substrate 12 on which the protective film 14 is provided can be more reliably ensured by the above predetermined surface of the pressure chamber substrate 13. It can be smaller than the surface roughness of the surface. Further, depending on the surface state of the flow path substrate 12, it is possible to make the surface of the protective film 14 formed on the flow path substrate 12 hardly generate unevenness. For this reason, in the adhesive 16 between the protective film 14 and the nozzle substrate 11, it is possible to make the gap less likely to occur.

  Further, by using an inorganic oxide or inorganic nitride containing at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta, and Si, or polyparaxylylene as the protective film 14, the pressure chamber substrate 13 can be used. It is possible to effectively suppress the occurrence of the problem that the base material 130 of the above is corroded by the ink.

  Further, the ink jet head 1 of the above embodiment includes the outlet 42 for discharging the ink to the outside, and the pressure chamber substrate 13 is provided with the common ink discharge flow path 132 communicating with the outlet 42. Has an individual ink discharge flow path 123 for guiding a part of the ink supplied from the pressure chamber 131 to the ink flow path 121 to the common ink discharge flow path 132 of the pressure chamber substrate 13. According to such a configuration, it is possible to discharge a part of the ink in the pressure chamber 131 that has not been discharged from the nozzle 111 from the outlet 42 together with air bubbles and foreign matter. As a result, it is possible to suppress the occurrence of a problem in which an appropriate pressure can not be applied to the ink in the pressure chamber 131 or a defect in which the nozzle 111 is clogged with foreign matter.

  Further, the surface of the surface on which the protective film 14 of the flow path substrate 12 is provided has an absolute height from the plane along the surface of the object to the surface, rather than the surface of the predetermined surface of the pressure chamber substrate 13 The arithmetic mean roughness Sa representing a value obtained by averaging the values in a two-dimensional range is small. Thus, by using the arithmetic mean roughness Sa, the surface roughness can be compared accurately. That is, in the arithmetic mean roughness Sa, since the average value of the two-dimensional range is used, the influence of minute scratches and foreign matter on the surface is suppressed, and a highly reliable value that accurately reflects the surface roughness is obtained. be able to.

  Moreover, since the inkjet recording apparatus 100 of the said embodiment is equipped with said inkjet head 1, it can suppress generation | occurrence | production of the leak of the ink in the layer of the adhesive agent 16 of the inkjet head 1. FIG. This can suppress the occurrence of the ink discharge failure.

Further, in the method of manufacturing the inkjet head 1 according to the above-described embodiment, the pressure chamber 131 for changing the pressure of the ink stored inside according to the deformation is formed in the base material 130 made of ceramic piezoelectric material. A process of manufacturing the pressure chamber substrate 13 (step S1 in FIG. 8), and a predetermined flow channel provided with the ink flow channel 121 with respect to a predetermined surface formed by the base 130 among the surfaces of the pressure chamber substrate 13 The step of fixing the substrate 12 so that the ink flow path 121 communicates with the pressure chamber 131 (step S2 in FIG. 8), the protective film 14 is formed on the surface of the flow path substrate 12 opposite to the pressure chamber substrate 13 side (Step S3 in FIG. 8), the nozzle substrate provided with the nozzle 111 is communicated with the pressure film 131 via the ink flow channel 121, the protective film 14 is opposite to the flow channel substrate 12 side ~ side The surface of the surface on which the protective film 14 of the flow path substrate 12 is provided includes the step of adhering to the surface via the adhesive 16 (step S4 in FIG. 8). The surface roughness is smaller than the surface.
According to such a method, as compared with the configuration in which the protective film 14 is formed directly on the base material 130 made of a piezoelectric material, the level difference of the unevenness on the surface of the protective film 14 can be reduced. As a result, even when foreign matter is mixed between the protective film 14 and the nozzle substrate 11, a void does not easily occur in the adhesive 16, and the occurrence of ink leakage in the layer of the adhesive 16 is suppressed. it can. As a result, the amount of ink supplied to the nozzles 111 may be reduced, or an unintended ink flow path between the nozzles may be generated in the layer of the adhesive 16, and the desired ink supply to the nozzles 111 may not be performed. Occurrence can be suppressed.

The present invention is not limited to the above embodiment and each modification, and various modifications are possible.
For example, in the above embodiment, the flow path substrate 12 provided with the ink flow path 121 including the individual ink discharge flow path 123 is described as an example of the intermediate board, but the configuration of the intermediate board is not limited thereto. . For example, a perforated substrate provided with the ink flow passage 121 formed only of the through flow passage 122 (through hole) which communicates the pressure chamber 131 and the nozzle 111 may be used as the intermediate substrate.

  In the above embodiment, the protective film 14 is formed on the protective film formation target laminated substrate including the flow path substrate 12, the pressure chamber substrate 13 and the wiring substrate 20, but the present invention is not limited to this. For example, the protective film 14 may be formed on a protective film formation target laminated substrate including the flow path substrate 12 and the pressure chamber substrate 13, and a protective film different from the protective film 14 may be formed on the wiring substrate 20. . Alternatively, the protective film 14 may be formed on the single flow path substrate 12 and then bonded to another substrate.

  Moreover, although arithmetic mean roughness Sa was used for the comparison with the surface roughness of the flow-path board | substrate 12 as an intermediate | middle board | substrate, and the surface roughness of the pressure chamber board | substrate 13 in the said embodiment, it is not the meaning limited to this. As the surface roughness, for example, the maximum height Sz, the maximum peak height Sp, the maximum valley depth Sv, the root mean square roughness Sq, etc. in a two-dimensional range may be used, or the flow path substrate 12 or pressure Arithmetic mean roughness Ra, maximum height Rz, maximum peak height Rp, maximum valley depth Rv, root mean square roughness Rq, and the like in a one-dimensional direction in a predetermined cross section of the chamber substrate 13 may be used.

  In the above embodiment, although the example in which the recording medium M is conveyed by the conveyance unit 80 including the conveyance belt 83 has been described, the invention is not limited thereto. The recording medium M may be held and transported on the surface.

  Although the single-pass type inkjet recording apparatus 100 has been described as an example in the above embodiment, the present invention may be applied to an inkjet recording apparatus that performs recording of an image while scanning the inkjet head 1.

  Although some embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and the equivalents thereof. .

Reference Signs List 1 inkjet head 10 head chip 11 nozzle substrate 111 nozzle 12 flow path substrate 121 ink flow path 122 through flow path 123 individual ink discharge flow path 123a horizontal individual discharge flow path 123b vertical individual discharge flow path 13 pressure chamber substrate 130 base material 131 pressure Chamber 132 common ink discharge flow path 132a horizontal common discharge flow path 132b vertical common discharge flow path 133 drive electrode 134 partition wall 135 connection electrode 14 protective film 15, 16 adhesive 20 wiring substrate 201 ink supply port 202 discharge hole 203 wiring 30 FPC
Reference Signs List 31 wiring 40 exterior member 41 inlet 42 outlet 80 transport unit 90 head unit 100 inkjet recording apparatus M recording medium

Claims (7)

An inkjet head that ejects ink from a nozzle,
A pressure chamber substrate having a base made of ceramic piezoelectric material and provided with a pressure chamber for changing the pressure of the ink stored therein according to the deformation;
An intermediate substrate fixed to a predetermined surface of the surface of the pressure chamber substrate and made by the base material and provided with an ink flow path communicating with the pressure chamber;
A protective film provided on the surface of the intermediate substrate opposite to the pressure chamber substrate side;
A nozzle substrate provided with the nozzle which is adhered to the surface of the protective film opposite to the intermediate substrate via an adhesive and which communicates with the pressure chamber through the ink flow path;
Equipped with
An inkjet head having a surface roughness smaller than a surface of the predetermined surface of the pressure chamber substrate, wherein the surface of the intermediate substrate on which the protective film is provided;   The inkjet head according to claim 1, wherein the intermediate substrate is made of Si, metal or glass.   The inkjet recording method according to claim 1 or 2, wherein the protective film is an inorganic oxide or inorganic nitride containing at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta, and Si, or polyparaxylylene. head. Equipped with an ink outlet for discharging ink to the outside,
The pressure chamber substrate is provided with a first discharge flow passage communicating with the ink discharge port,
The ink flow path according to any one of claims 1 to 3, wherein the ink flow path has a second discharge flow path for guiding a part of the ink supplied from the pressure chamber to the ink flow path to the first discharge flow path of the pressure chamber substrate. An inkjet head according to any one of the preceding claims.   The surface of the surface on which the protective film of the intermediate substrate is provided has an absolute value of the height from the plane along the surface of the object to the surface of the surface of the predetermined surface of the pressure chamber substrate. The inkjet head according to any one of claims 1 to 4, wherein an arithmetic mean roughness Sa representing a value averaged in a range of dimensions is small.   An inkjet recording apparatus comprising the inkjet head according to any one of claims 1 to 5. A method of manufacturing an ink jet head for discharging ink from a nozzle, comprising:
Forming a pressure chamber for changing the pressure of the ink stored therein according to the deformation on a substrate made of ceramic piezoelectric material, and manufacturing a pressure chamber substrate having the substrate;
Fixing a predetermined intermediate substrate provided with an ink flow passage to a predetermined surface of the pressure chamber substrate made by the base material so that the ink flow passage communicates with the pressure chamber;
Forming a protective film on the surface of the intermediate substrate opposite to the pressure chamber substrate side;
The nozzle substrate provided with the nozzle is adhered to the surface of the protective film opposite to the intermediate substrate via an adhesive so that the nozzle communicates with the pressure chamber via the ink flow path. The process to
Including
A surface of the surface of the intermediate substrate on which the protective film is provided has a smaller surface roughness than a surface of the predetermined surface of the pressure chamber substrate.

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