JP7512118B2 - LIQUID EJECTION HEAD, METHOD OF MANUFACTURING LIQUID EJECTION HEAD, AND IMAGE RECORDING APPARATUS - Google Patents

Description

The present invention relates to a liquid ejection head, a method for manufacturing a liquid ejection head, and an image recording device.

Conventionally, inkjet heads, which are liquid ejection heads that eject liquid such as ink, are required to output higher quality images at faster printing speeds. In recent years, various types of inkjet heads have been produced as a means of responding to these demands. Accordingly, a wide variety of materials are used in the manufacturing process for the ink ejection device (liquid ejection device), which is one of the units that make up an inkjet head, depending on the purpose. Patent Document 1 describes a method for manufacturing an inkjet head in which two types of adhesives are used to bond the ink ejection device to the support.

JP 2006-312252 A

In recent years, ink ejection devices are often constructed by combining a wide variety of components, such as components with high thermal insulation properties and sealing materials containing special additives. Depending on the configuration, the linear expansion difference between each component, such as the chip, support, and sealing material, may become large. When an ink ejection device is constructed by placing components with large linear expansion differences close to each other, stress is concentrated at the joints between the components due to temperature changes with altitude differences, and sometimes there is a risk that some of the components that make up the ink ejection device may be damaged.

The object of the present invention is to provide a liquid ejection head that can reduce the stress concentrated at the joints between components.

In order to solve the above problems, the liquid ejection head of the present invention comprises:
a chip including a liquid ejection port opening in a first surface, an electrode portion provided on the first surface and electrically connected to an outside, and a resin film provided on a second surface which is a reverse surface of the first surface;
a support having a support surface for supporting the second surface of the chip;
A sealant that covers the electrode portion;
an adhesive that bonds between the second surface of the chip and the support surface of the support;
A liquid ejection head including a liquid ejection device having
The adhesive is
a first adhesive disposed in a first application region between a region of the second surface located on the back side of the electrode portion and the support surface;
a second adhesive disposed in a second application area different from the first application area and between at least a portion of the resin film and the support surface;
Including,
The hardness of the first adhesive is lower than the hardness of the second adhesive.

The above configuration makes it possible to provide a liquid ejection head that can reduce the stress concentrated at the joints between components.

1 is a schematic plan view of an inkjet printer according to an embodiment of the present invention. 1A and 1B are a plan view and an enlarged plan view of an inkjet head according to an embodiment of the present invention. 5A to 5C are plan views illustrating a method for manufacturing the ink ejection device according to the first embodiment. 3(d) and an enlarged schematic cross-sectional view thereof. 10A to 10C are plan views illustrating a method for manufacturing an ink ejection device according to a second embodiment. 5B is a schematic cross-sectional view taken along line FF in FIG. 5B, and FIG. 5C is a schematic cross-sectional view taken along line GG in FIG. 5(d) is a schematic cross-sectional view taken along line HH of FIG. 5(d) and an enlarged schematic cross-sectional view.

The following describes in detail the embodiments of the present invention with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiments should be changed as appropriate depending on the configuration and various conditions of the device to which the invention is applied. In other words, it is not intended to limit the scope of the present invention to the embodiments described below.

(Embodiment 1)
(Inkjet printer)
First, the schematic configuration of an inkjet printer 1 as an image recording apparatus of this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic plan view showing the plan configuration of the inkjet printer 1 of this embodiment. The inkjet printer 1 includes an inkjet head (liquid ejection head) 3 for recording an image or the like on a recording paper 2 as a recording material, a carriage 4 for holding the inkjet head 3, and a transport mechanism 5 (rollers, etc.) for transporting the recording paper 2. A platen 7 for supporting the recording paper 2 is provided in a printer housing 6, and two guide rails 8a, 8b are provided above the platen 7. The carriage 4 is driven by a carriage drive motor (not shown) and can move along the two guide rails 8a, 8b.

The inkjet head 3 is attached horizontally to the bottom of the carriage 4 with a gap between it and the platen 7. A plurality of ink ejection devices (liquid ejection devices) 21 are arranged on the bottom surface of the inkjet head 3, forming an ink ejection section (liquid ejection section) 3a. The inkjet head 3 is also connected to the ink cartridge holder 9 by tubes (not shown). Four ink cartridges 10a, 10b, 10c, and 10d are attached to the ink cartridge holder 9, and magenta, cyan, yellow, and black inks are supplied to the inkjet head 3 via the tubes as the ejection liquid.

The maintenance unit 11 is provided with a cap 12, a suction pump 13, and a wiper 14. The cap 12 is driven to move up and down by a cap drive unit (not shown) composed of a motor drive source and a gear power transmission mechanism. The cap 12 is moved upward by the cap drive unit and is brought into close contact with the ink discharge unit 3a of the inkjet head 3, thereby performing capping. After capping, the suction pump 13 connected to the cap 12 performs suction purge, which sucks air from inside the cap 12 and reduces the pressure inside the cap 12 to forcibly discharge ink from the ink discharge unit 3a of the inkjet head 3 into the cap 12. This suction purge discharges air bubbles and dust mixed in the ink, or thickened ink, thereby suppressing deterioration of recording quality. The wiper 14 is arranged to perform wiping to wipe off ink adhering to the ink discharge unit 3a of the inkjet head 3 when the inkjet head 3 moves to the ink discharge position after the suction purge.

As described above, the inkjet printer 1 is configured so that the inkjet head 3 ejects ink while the recording paper 2 is transported toward the recording paper discharge section 15 by the transport mechanism 5, thereby recording images, characters, etc., on the recording paper 2.

(Inkjet head)
Fig. 2(a) is a plan view of the inkjet head 3 manufactured by the manufacturing method of this embodiment, and Fig. 2(b) is an enlarged plan view of the ink discharge device 21. The inkjet head 3 has a base plate 20 provided with a plurality of ink flow paths (liquid flow paths) communicating with ink discharge holes (liquid discharge holes) 27, and a plurality of ink discharge devices 21 bonded to the base plate 20. The ink discharge device 21 is composed of a chip 26 provided with a plurality of ink discharge holes 27 (forming liquid discharge ports) that open on a front surface (first surface), a support 22 that supports the back surface (second surface) of the chip 26, a sealant 29 for protecting electrical connections, a wiring board 30, etc.

The chip 26, which is a semiconductor chip, has an energy generating element inside each ink ejection hole 27, for example, and the ink ejection operation is controlled by receiving an electric signal or power used to drive the energy generating element via the wiring board 30 or the electrode part 28 described later. The chip 26 has a silicon substrate on the surface of which an energy generating element is formed, and an ejection port forming member on which ink ejection holes 27 corresponding to the energy generating elements are formed. The chip 26 has an electrode part 28 on the silicon substrate for electrical connection with the outside of the chip 26. In addition, although not shown here, the inkjet head 3 is joined to an electric wiring board, a head cover, and a reference jig for mounting with an inkjet printer. In this embodiment, eight ink ejection devices 21 are aligned and joined, but the length and shape of the base plate 20 may be changed depending on the application, and the arrangement of the ink ejection devices 21 may be changed.

Figures 3(a) to 3(d) show, in chronological order, the method for manufacturing the ink ejection device 21 according to the manufacturing method of this embodiment.

3A is a plan view of the support 22 used in the manufacturing method of this embodiment. In this embodiment, an alumina material having insulating properties, thermal conductivity, and mechanical strength is used as the material of the support 22. In addition, the support 22 is provided with an ink flow path hole (liquid flow path hole) 23 for supplying ink to the ink ejection hole 27 provided in the chip 26. The ink flow path hole as the second flow path opening is opened on the support surface 22a of the support 22. In this embodiment, the ink flow path hole 23 for one ink ejection device is composed of four openings arranged at intervals in a direction perpendicular to the longitudinal direction, but this is not limited to this and may be composed of any number of openings. Then, a first adhesive 24 is applied to the support surface 22a of the support 22 in a manner that sandwiches the ink flow path hole 23 adjacently on both sides in the longitudinal direction. The first adhesive 24 is applied so as to be near the lower surface of the electrode part 28 described later. In addition, the physical properties of the first adhesive 24 are preferably such that the Young's modulus (modulus of longitudinal elasticity) at an environmental temperature equivalent to 100°C is 3 GPa or less, and more preferably 0.1 GPa or less. The area where the area located on the back side of the electrode portion 28 on the back side of the chip 26 faces the support surface 22a, or the area of the support surface 22a facing the back side area of the electrode portion 28 on the back side of the chip 26 corresponds to the first application area where the first adhesive 24 is applied.

3B, the second adhesive 25 is applied to the adjacent portion of the ink flow path hole 23. In this embodiment, the second adhesive 25 has a Young's modulus of about 10 GPa at an environmental temperature of 100° C. The chip 26 and the support 22 are bonded in a later process, and the second adhesive 25 is applied in a form that connects with the first adhesive 24 (having a contact interface) so that the bonded surface does not leak to the outside. As shown in FIG. 3B, the second adhesive 25 is disposed in a form that is sandwiched between the first adhesive 24, and the ink flow path pitch conversion hole of the resin film 35 described later is surrounded by the first adhesive 24 and the second adhesive 25. The second application area where the second adhesive 25 is applied is an area different from the first application area between the back surface of the chip 26 and the support surface 22a, or an area different from the first application area of the support surface 22a facing the back surface of the chip 26. The second application area includes the area between at least a portion of the resin film 35 constituting the rear surface of the chip 26 and the support surface 22a, or the area of the support surface 22a facing at least a portion of the resin film 35 constituting the rear surface of the chip 26.

In this embodiment, the first adhesive 24 is applied first, and then the second adhesive 25 is applied, but the order of application of the first adhesive 24 and the second adhesive 25 may be reversed. The application height of the first adhesive 24 is set to be equal to or greater than the application height of the second adhesive 25. This is because if the application height of the second adhesive 25 becomes higher than that of the first adhesive 24, the second adhesive 25 may protrude onto the upper surface of the application of the first adhesive 24, which may reduce the effect of relaxing the stress concentrated at the joint between the chip 26 and the support 22. In this embodiment, both the first adhesive 24 and the second adhesive 25 are applied to the support 22 by an application program stored in the application robot, but a transfer method may be used to form an application pattern other than the application method. In addition, a thermosetting adhesive is used for the first adhesive 24 and the second adhesive 25, but a UV thermosetting adhesive or a thermoplastic film may also be used.

Figure 3(c) shows the state in which the support 22 coated with the first adhesive 24 and the second adhesive 25 is bonded to the chip 26. In this embodiment, a thermosetting adhesive is used for the first adhesive 24 and the second adhesive 25, so the chip 26 is pressed and bonded in a heated state. Note that the bonding method is not limited to this embodiment, and a bonding method using a combination of UV light and heat, or a bonding method using a temporary adhesive may also be used depending on the physical properties of the adhesive used.

Next, as shown in FIG. 3(d), the wiring board 30 is bonded to the upper surface of the support 22. In this embodiment, the bonding is performed using a UV thermosetting adhesive, but the bonding method is not limited to this. After bonding the support 22 and the wiring board 30, the electrode portion 28 on the upper surface of the chip 26 and the electrode pad (not shown) on the upper surface of the wiring board 30 are connected with the wiring member 31 (shown in FIG. 4). Then, the wiring member 31 is covered with the sealing material 29, and the sealing material 29 is hardened by a curing process, completing the ink discharge device 21. The completed ink discharge devices 21 are bonded to the base plate 20 as shown in FIG. 2(a), and the ink jet head 3 is completed by bonding the electric wiring board, the head cover, and the connection jig to the ink jet printer, which are not shown here.

Here, we will use Figure 4 to explain the stress concentration at part C of the chip end.

Figure 4 (a) is a cross section taken along the line A-A in Figure 3 (d). In order to easily connect the chip 26 to the wiring board 30 electrically, the electrode portion 28 is disposed at the chip end C. In order to protect the electrode portion 28 and the wiring member 31 from corrosion caused by ink, the periphery of the electrode portion 28 is robustly covered with a sealant 29. As a result, the chip end C is covered with various members, and the support 22, the chip 26, and the sealant 29 have different expansion and contraction rates due to the difference in environmental temperature, so that the joints (joint interfaces) between the members are structured in such a way that stress tends to concentrate. Therefore, as in this embodiment, the first adhesive 24, which has a lower Young's modulus than the second adhesive 25, which is an adhesive for joining the chip 26 and the support 22, is disposed at the back surface D of the chip end C, where stress tends to concentrate. As a result, the first adhesive 24 absorbs the deformation of the chip end C due to stress, and the chip end C becomes more easily deformed, making it possible to alleviate the stress concentrated at the chip end C.

Next, FIG. 4(b) is a schematic diagram of an enlarged view of the B portion of FIG. 4(a). When the chip 26 and the support 22 are joined, a part of the first adhesive 24 protrudes from the lower surface of the chip end C portion, and the protruding part creeps up the side wall of the chip end C portion to form an adhesive protrusion E portion. The larger the contact area of the adhesive protrusion E portion with respect to the side wall of the chip end C portion, the greater the force absorbing the deformation of the chip end C portion, and the greater the effect of alleviating the stress concentrated in the chip end C portion. For this reason, it is preferable that the height T2 of the adhesive protrusion E portion is half or more of the thickness T1 of the chip 26, and it is more preferable that the height T2 of the adhesive protrusion E portion is closer to the thickness T1 of the chip 26. However, if the height T2 of the adhesive protrusion E portion exceeds the thickness T1 of the chip 26, the first adhesive 24 may block a part of the ink ejection hole 27 provided in the chip 26, although this is not shown here. If part of the ink ejection hole 27 is blocked, the print quality will deteriorate, so it is necessary to control the amount of first adhesive 24 applied so that the height T2 of the adhesive overflow E does not exceed the thickness T1 of the chip 26.

Next, we will explain the relationship between the adhesive used to bond the chip 26 and the resin film 35 provided on the back surface (second surface) of the chip 26.

As shown in FIG. 4A, in this embodiment, the chip 26 has a resin film 35 on the back surface thereof, and the resin film 35 constitutes a part of the back surface (second surface) of the chip 26. A plurality of ink flow path pitch conversion holes (not shown) are formed in the resin film 35. The ink flow path pitch conversion holes as the first flow path openings opened on the back surface of the chip 26 are for converting the pitch of the ink flow path holes 23 of the support body 22 to the pitch of the ink supply ports (supply holes) 27 of the chip 26. In this embodiment, the resin film 35 is formed to a thickness of 10 to 30 μm , which is a very thin film thickness configuration, and is therefore susceptible to the influence of deformation of the surrounding members. This resin film 35 has a thickness thinner than that of the silicon substrate on which the energy generating elements are formed, which constitutes the chip 26. For example, if the adhesive in contact with the resin film 35 softens due to an increase in the environmental temperature and is deformed because it cannot maintain its hardness, the resin film 35 may also deform in accordance with the deformation, and the adhesion between the chip 26 and the resin film 35 may deteriorate. Therefore, the adhesive used to bond the chip 26 is required to have physical properties that enable it to maintain its hardness even when the environmental temperature rises to 100° C. or higher, so that it is not easily affected by changes in the environmental temperature. Specifically, the second adhesive 25 used to bond the chip 26 and the support 22 in this embodiment has a Young's modulus of 10 GPa or more at environmental temperatures of 0° C. to 100° C. As a result, even if the environmental temperature reaches 100° C., the second adhesive 25 maintains its hardness, making it less likely to deform, and making it possible to suppress deformation of the resin film 35.

The first adhesive 24 in this embodiment has a physical property in which the Young's modulus changes from 0.01 GPa to 4.8 GPa at an environmental temperature of 0°C to 100°C. If the first adhesive 24 were used to bond the chip 26 to the support 22 as a substitute for the second adhesive 25, the first adhesive 24 and the resin film 35 would deform as the environmental temperature increased, and therefore the first adhesive 24 would not be used as a substitute for the second adhesive 25. For this reason, the contact area ratio of the first adhesive 24 and the second adhesive 25 to the chip 26 is necessarily smaller for the first adhesive 24.

(Embodiment 2)
5(a) to 5(d) show, in chronological order, a method for manufacturing the ink ejection device 21 according to the manufacturing method of the second embodiment. Note that in the description of the second embodiment, descriptions of the same configurations and steps as those of the first embodiment will be simplified or omitted.

Figure 5 (a) shows the state where the second adhesive 25 has been applied onto the support surface 22a. The difference from the first embodiment in the application pattern of the second adhesive 25 is that the second adhesive 25 is applied to the location where the first adhesive 24 has been applied.

In FIG. 5(b), the support 22 coated with the second adhesive 25 is joined to the chip 26 provided with a plurality of ink ejection holes 27. After joining the chip 26, the first adhesive 24 is ejected from the application needle 32 toward the application range 33 of the first adhesive 24. FIG. 6(a) is an F-F cross section of FIG. 5(b) showing the state before the first adhesive 24 is applied, and the first adhesive 24 is applied (injected) toward the gap 34. The gap 34 is a gap between the back surface of the joined chip and the support surface 22a, and is a gap outside the area where the second adhesive 25 is applied and where the area located on the back side of the electrode portion 28 on the back surface of the chip faces the support surface 22a.

Figure 5(c) shows the state after the first adhesive 24 has been applied. Figure 6(b) is a cross section taken along line G-G of Figure 5(c), but the preferred height of the adhesive overflow E of the first adhesive 24 and the stress relaxation effect of the first adhesive 24 are the same as in embodiment 1, so a description thereof will be omitted. Note that the first adhesive 24 and the second adhesive 25 may be in a non-contact state, or may have a configuration in which contacting and non-contacting portions are mixed.

Figure 5(d), Figure 7(a) which is a cross section taken along line H-H in Figure 5(d), and Figure 7(b) which is an enlarged schematic diagram of part I in Figure 7(a) show the state in which the ink ejection device 21 is completed after bonding of the wiring board 30 and covering with the sealing material 29. The subsequent steps are the same as those in the first embodiment, so a description thereof will be omitted.

In this embodiment, Young's modulus (modulus of longitudinal elasticity) is used as an index of hardness (hardness), but this is not limiting and other indices may be used. In addition, the value of Young's modulus when the environmental temperature is 100°C as the specified device usage environment has been described, but the environmental temperature when comparing hardness is not limited to 100°C and other temperatures may be used for comparison as appropriate depending on the device specifications, etc. The same applies to the magnitude of Young's modulus.

21...ink ejection device, 22...support, 24...first adhesive, 25...second adhesive, 26...chip, 28...electrode portion, 29...sealant, 30...wiring board, 35...resin film, C section...chip end, D section...chip back surface, E section...adhesive overflow, T1...chip thickness, T2...adhesive overflow height

Claims (17)

a chip including a liquid ejection port opening in a first surface, an electrode portion provided on the first surface and electrically connected to an outside, and a resin film provided on a second surface which is a reverse surface of the first surface;
a support having a support surface for supporting the second surface of the chip;
A sealant that covers the electrode portion;
an adhesive that bonds between the second surface of the chip and the support surface of the support;
A liquid ejection head including a liquid ejection device having
The adhesive is
a first adhesive disposed in a first application region between a region of the second surface located on the back side of the electrode portion and the support surface;
a second adhesive disposed in a second application area different from the first application area and between at least a portion of the resin film and the support surface;
Including,
A liquid ejection head, wherein the hardness of the first adhesive is lower than the hardness of the second adhesive. The liquid ejection head according to claim 1, characterized in that the sealing material covers an area of the first surface including the electrode portion so as to overlap the first application area. the resin film includes a first flow path opening on the second surface through which the liquid to be discharged from the liquid discharge port flows;
3. The liquid ejection head according to claim 1, wherein the second application area is an area surrounding the first flow path opening. The liquid ejection head according to any one of claims 1 to 3, characterized in that the first adhesive and the second adhesive have a contact interface. a wiring board electrically connected to the electrode portion and joined to the support surface;
5. The liquid ejection head according to claim 1, wherein the first adhesive is disposed between the wiring board and the second adhesive on the supporting surface. The electrode portion is provided at an end portion of the tip,
6. The liquid ejection head according to claim 1, wherein the first adhesive is also in contact with a side wall of the end portion of the chip. The liquid ejection head according to claim 6, characterized in that the height of the area of the first adhesive that contacts the side wall does not exceed the thickness of the chip. The liquid ejection head according to any one of claims 1 to 7, characterized in that the contact area of the first adhesive with respect to the chip is smaller than the contact area of the second adhesive with respect to the chip. The liquid ejection head described in any one of claims 1 to 8, characterized in that the Young's modulus of the first adhesive is smaller than the Young's modulus of the second adhesive at a predetermined environmental temperature. a second flow path opening for allowing a liquid to flow in the chip is provided on the support surface of the support in a plurality of rows spaced apart from one another in a direction perpendicular to the longitudinal direction;
the first application region is a region adjacent to both sides of the second flow path opening in the longitudinal direction,
10. The liquid ejection head according to claim 1, wherein the second application area is an area adjacent to the second flow path opening in a direction perpendicular to the longitudinal direction. a second flow path opening for allowing a liquid to flow in the chip is provided on the support surface of the support in a plurality of rows spaced apart from one another in a direction perpendicular to the longitudinal direction;
the second application region is a region adjacent to and surrounding each of the second flow path openings,
10. The liquid ejection head according to claim 1, wherein the first coating region is adjacent to the second coating region on both sides in the longitudinal direction. The liquid ejection head according to claim 1 , comprising a plurality of the liquid ejection devices. The liquid ejection head according to claim 1 , wherein the support has a flow path for supplying liquid to the tip. a chip including a liquid ejection port opening in a first surface, an electrode portion provided on the first surface and electrically connected to an outside, and a resin film provided on a second surface which is a reverse surface of the first surface;
a support having a support surface for supporting the second surface of the chip;
A sealant that covers the electrode portion;
an adhesive that bonds between the second surface of the chip and the support surface of the support;
A method for manufacturing a liquid ejection head having a liquid ejection device comprising:
a first application step of applying a first adhesive to a first application area on the support surface of the support body, the first application area facing an area located on the back side of the electrode portion on the second surface of the chip;
a second coating step of coating a second adhesive having a hardness higher than that of the first adhesive in a second coating area on the support surface of the support body, the second coating area being different from the first coating area and facing at least a portion of the resin film;
a joining step of joining the second surface and the support surface to adhere the chip and the support;
A method for manufacturing a liquid ejection head, comprising: a chip including a liquid ejection port opening in a first surface, an electrode portion provided on the first surface and electrically connected to an outside, and a resin film provided on a second surface which is a reverse surface of the first surface;
a support having a support surface for supporting the second surface of the chip;
A sealant that covers the electrode portion;
an adhesive that bonds between the second surface of the chip and the support surface of the support;
A method for manufacturing a liquid ejection head having a liquid ejection device comprising:
a second application step of applying a second adhesive to a second application region on the support surface of the support body, the second application region facing at least a portion of the resin film;
a joining step of joining the second surface and the support surface to adhere the chip and the support;
a first application step of injecting and applying a first adhesive having a hardness lower than that of the second adhesive into a first application area, the first application area being a gap between the joined second surface and the support surface, the first adhesive being outside the second application area and being a gap between a region of the second surface located on the back side of the electrode portion and the support surface;
A method for manufacturing a liquid ejection head, comprising: The method for manufacturing a liquid ejection head according to claim 14 or 15, wherein at least one of the first adhesive and the second adhesive is a thermosetting adhesive. An image recording apparatus comprising the liquid ejection head according to any one of claims 1 to 13 .

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