Liquid discharge head and liquid discharge device

Abstract

To provide a liquid discharge head that can suppress an adhesive from creeping up into a common flow path, when the adhesive bonds substrates to each other.SOLUTION: A liquid discharge head comprises a liquid discharge substrate for discharging liquid. The liquid discharge substrate is configured to have a flow path forming substrate and a support substrate bonded to the flow path forming substrate through an adhesive. The flow path forming substrate has a common flow path communicated with a flow oath formed in the support substrate and an individual flow path communicated with the common flow path, where an angle of a corner part closest to the individual flow path, of corner parts at the end part of the common flow path, is larger than 90°.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection apparatus, and more particularly to a technique for stacking and bonding together a plurality of substrates that constitute a liquid ejection head. [Background technology]

[0002] Some liquid ejection heads are formed by laminating a flow path substrate, in which flow paths for supplying liquid such as ink to ejection ports are formed, on a support substrate. Patent Document 1 describes that the laminated substrates are bonded together with an adhesive. In more detail, the adhesive is prevented from spilling out of the bonded portion by controlling the undulation of the adhesive layer when the adhesive layer is transferred to the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-61022 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, even if the adhesive overflows only slightly, it overflows onto the wall surfaces of the partition walls that form the flow paths of the flow path forming substrate and onto the support substrate. The adhesive particularly creeps up the corners formed by two adjacent sides of the support substrate and the partition walls. When the angle of the corner is acute or right angle, the adhesive is likely to creep up the corners due to surface tension. In this way, when a large amount of adhesive creeps up the corners of the partition walls of the flow path forming substrate, the individual flow paths that communicate with the common flow path formed in the flow path forming substrate are blocked by the creeping adhesive, making it impossible to supply liquid from the individual flow paths to the energy generating elements, which may cause problems that impair the liquid ejection performance of the liquid ejection head.

[0005] The object of the present disclosure is to provide a liquid ejection head and a liquid ejection device that can suppress the adhesive from creeping up into the corners of the common flow path due to surface tension when a flow path forming substrate is joined to a support substrate via an adhesive, thereby preventing individual flow paths from being blocked by adhesive. [Means for solving the problem]

[0006] The liquid ejection head of the present disclosure includes a liquid ejection substrate for ejecting liquid, the liquid ejection substrate being configured to include a flow path forming substrate and a support substrate bonded to the flow path forming substrate via an adhesive, the flow path forming substrate having a common flow path communicating with a flow path formed in the support substrate and individual flow paths communicating with the common flow path, and the angle of the corner of the end of the common flow path closest to the individual flow path is greater than 90°. Effect of the Invention

[0007] According to the above configuration, when the flow path forming substrate is joined to the support substrate via an adhesive, in the liquid ejection head, the adhesive is prevented from creeping up into the corners of the common flow path due to surface tension, thereby preventing the individual flow paths from being blocked by the adhesive. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a cross section of a portion of a liquid ejection substrate that constitutes a liquid ejection head according to a first embodiment of the present disclosure. [Diagram 2] 2 is a cross-sectional view of a portion of the liquid ejection substrate shown in FIG. [Diagram 3] 2 is a diagram showing the flow path forming substrate of the liquid ejection substrate shown in FIG. 1, viewed from the underside thereof. [Figure 4] FIG. 4 is an enlarged view of part A in FIG. [Diagram 5] FIG. 5 is an enlarged view of part B in FIG. [Figure 6] 11A and 11B are diagrams illustrating a liquid ejection substrate according to a second embodiment of the present disclosure. [Figure 7] FIG. 7 is an enlarged view of part C in FIG. [Figure 8]1 is a perspective view illustrating a liquid ejection head according to an embodiment of the present disclosure. [Figure 9] 1 is a perspective view showing a schematic diagram of an ink jet recording apparatus according to an embodiment of a liquid ejection apparatus; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of each component of the embodiments described below may be changed as appropriate depending on the configuration of the liquid ejection substrate of the liquid ejection head to which the present disclosure is applied, and various conditions. The scope of the present disclosure is not limited to the embodiments described below.

[0010] (Embodiment 1) Fig. 1 is a perspective view showing a cross section of a part of a liquid ejection substrate constituting a liquid ejection head according to this embodiment, and Fig. 2 is a cross section of a part of the liquid ejection substrate shown in Fig. 1. As shown in Fig. 1 and Fig. 2, the liquid ejection substrate 10 includes a flow path forming substrate 100, a support substrate 300 joined to the flow path forming substrate 100 via an adhesive 200, and an energy generating element 400 provided on the flow path forming substrate 100 and configured to generate energy used to eject liquid.

[0011] The liquid ejection substrate 10 of this embodiment is mounted in an inkjet recording device as a liquid ejection device and ejects ink as a liquid.

[0012] A flow path layer 150 and a nozzle layer 160 are laminated on an upper surface 111 of the flow path forming substrate 100 in ranges corresponding to the portions to be formed, and ejection ports 120, pressure chambers 118, etc. are formed. A lower surface 112 of the flow path forming substrate 100 is bonded to a support substrate 300 via an adhesive 200. In addition, a pitch conversion flow path 320 connected to a common flow path 132 formed in the flow path forming substrate 100 is formed in the support substrate 300.

[0013] The liquid ejection substrate 10 according to the present embodiment described above is divided into a flow path region 130 and a joining region 140 in a direction perpendicular to the arrangement direction of the ejection ports 120, as shown in FIG.

[0014] In the flow path region 130, there are a common flow path 132 for supplying liquid to the energy generating elements 400, individual flow paths 134 communicating with the common flow path 132, and pressure chambers 118 in which the energy generating elements 400 are provided. The liquid travels from the common flow path 132 through the individual flow paths 134 to reach the pressure chambers 118, and the liquid that has reached the pressure chambers 118 is ejected from ejection ports 120 communicating with the pressure chambers 118 as a result of the energy generating elements 400 generating energy.

[0015] Moreover, the common flow channel 132 has a supply flow channel 132a for supplying liquid to the energy generating elements 400, and a recovery flow channel 132b for recovering the liquid that is supplied to the energy generating elements 400 and not used for ejection. In this manner, the flow channel region 130 is a region where the lower surface 112 of the partition wall 136 for forming each flow channel is bonded to the support substrate 300 by the adhesive 200.

[0016] 1 and 2 again, the bonding region 140 is a region in the flow-path substrate 100 where a flow path is adjacent to only one side. That is, in this region, the portion where the lower surface 112 of the flow-path substrate 100 is bonded to the support substrate 300 is a region where ink does not leak through this bonding portion. A plurality of recesses (grooves) 142 for receiving adhesive are provided on the lower surface side of the flow-path substrate 100 in this region.

[0017] In this embodiment, the energy generating element 400 is a heating resistor, but may be in another form, for example, a piezoelectric element. Wiring for supplying power to the energy generating element 400 and pads for connecting electrodes are not shown. The adhesive 200 is preferably made of a material that has high adhesion to the flow path forming substrate 100 and the support substrate 300, and is preferably made of a material that has little air bubbles and is highly coatable, and is preferably made of a low viscosity material that makes it easy to reduce the thickness of the adhesive 200. For example, the adhesive 200 may contain any resin selected from the group consisting of epoxy resin, acrylic resin, silicone resin, benzocyclobutene resin, polyamide resin, polyimide resin, and urethane resin.

[0018] Furthermore, the adhesive 200 may be cured by a heat curing method or an ultraviolet delayed curing method. When the flow path forming substrate 100 or the support substrate 300 has ultraviolet transmittance, the adhesive 200 may be cured by an ultraviolet ray.

[0019] Moreover, as a method for applying the adhesive 200, an adhesive transfer method depending on the substrate to be used can be mentioned. Specifically, a transfer substrate is prepared, and the adhesive 200 is applied thinly and uniformly on the transfer substrate by a spin coating method or a slit coating method. Thereafter, the adhesive 200 can be transferred only to the lower surface 112 of the flow path forming substrate 100 by contacting the applied adhesive 200 with the lower surface 112 of the flow path forming substrate 100. The size of the transfer substrate is preferably equal to or larger than the size of the flow path forming substrate 100. As the transfer substrate, silicon, glass, or a film such as PET, PEN, or PI is preferably used. Furthermore, as a method for directly forming the adhesive 200 on the flow path forming substrate 100, screen printing and dispense application can be mentioned. Although the above description is given by taking the flow path forming substrate 100 as an example, the adhesive may be applied to the third surface 311 of the support substrate 300 to be bonded to the flow path forming substrate 100 as the same application method.

[0020] The flow path forming substrate 100 and the support substrate 300 coated with the adhesive 200 are bonded by heating the flow path forming substrate 100 and the support substrate 300 to a predetermined temperature in a bonding device, and then pressing them for a predetermined time and pressure. These bonding parameters are appropriately set depending on the adhesive material. In addition, in order to prevent air bubbles from entering the bonding portion of the flow path forming substrate 100 and the support substrate 300, it is preferable to bond the flow path forming substrate 100 and the support substrate 300 in a vacuum.

[0021] When the adhesive 200 is a thermosetting type, the adhesive 200 may be heated in a bonding device until it hardens. The bonded substrate assembly may be removed after bonding and heated in an oven or the like to promote the hardening of the adhesive 200. On the other hand, when the adhesive 200 is an ultraviolet delay type, the flow path forming substrate 100 is bonded to the support substrate 300 after a specified amount of ultraviolet light is irradiated to the adhesive 200 before bonding the support substrate 300 to the flow path forming substrate 100. After bonding the support substrate 300 to the flow path forming substrate 100, it is preferable to further heat the substrate assembly to sufficiently promote the hardening of the adhesive 200. When the adhesive 200 is an ultraviolet hardening type, after bonding the flow path forming substrate 100 and the support substrate 300, a specified amount of ultraviolet light is irradiated to the adhesive 200 on a substrate (the flow path forming substrate 100 and / or the support substrate 300) having ultraviolet light transparency to cure the adhesive 200. After the flow path forming substrate 100 is joined to the support substrate 300, it is preferable to further heat the substrate assembly to sufficiently promote hardening of the adhesive 200.

[0022] Fig. 3 is a diagram of the flow path forming substrate 100 of the liquid ejection substrate 10 shown in Fig. 1, seen from its underside, and Fig. 4 is an enlarged view of part A in Fig. 3. As shown in Fig. 3 and Fig. 4, the common flow path 132 extends along the longitudinal end 121a of the flow path forming substrate 100, and a plurality of individual flow paths 134 are arranged along the longitudinal end 132d of the common flow path 132 and are connected to the common flow path 132 to communicate with each other.

[0023] The common flow path 132 has corners 133a, 133b, 133c, and 133d provided at an end 133 of the common flow path 132. The corners 133a, 133b, 133c, and 133d may be provided at two opposing end portions 133. In the present embodiment, an example is shown in which one end portion 133 has four corners 133a, 133b, 133c, and 133d, but the number of corners 133a, 133b, 133c, and 133d may be four or more, and is not limited to four.

[0024] 5 is an enlarged view of part B in FIG. 4. As shown in FIG. 5, in the liquid ejection head of this embodiment, when the angles of the corners 133a, 133b, 133c, and 133d formed at the end 133 of the common flow path 132 are θ1, θ2, θ3, and θ4, respectively, the angle θ1 of the corner 133a closest to the individual flow path 134 is set to an angle greater than 90°. In this embodiment, the angles θ2, θ3, and θ4 of the corners 133b, 133c, and 133d are also set to angles greater than 90°. In this embodiment, each of the corners 133a, 133b, 133c, and 133d is curved. When the radii of curvature of this curve are R1, R2, R3, and R4, respectively, these values ​​correspond to the angles θ1, θ2, θ3, and θ4, respectively. For example, when the angle θ1 of the corner 133a closest to the individual flow paths 134 is the largest, the radius of curvature R1 also becomes the largest. With the above configuration, when the flow path forming substrate 100 is bonded to the support substrate 300 via the adhesive 200, it is possible to prevent the adhesive 200 from creeping up along the corners 133a, 133b, 133c, and 133d of the common flow path 132. In particular, with the configuration in which the angle θ1 of the corner 133a closest to the individual flow paths 134 is greater than 90 degrees, it is possible to prevent the individual flow paths 134, to which the adhesive is more likely to come, from being blocked by the adhesive 200.

[0025] Furthermore, by providing multiple corners 133a, 133b, 133c, and 133d at the end 133 of the common flow path 132, when the flow path forming substrate 100 is joined to the support substrate 300 via the adhesive 200, the creeping of the adhesive 200 is dispersed to the corners 133a, 133b, 133c, and 133d, and the creeping of the adhesive 200 due to surface tension within the corners 133a, 133b, 133c, and 133d can be further suppressed. As a result, the adhesive 200 does not block the individual flow paths 134, and a liquid ejection substrate 10 with a high yield can be obtained.

[0026] In the manufacturing method of the liquid ejection substrate 10 in this embodiment, the energy generating elements 400 made of TaSiN and used to eject droplets, an electric circuit (not shown) that drives the energy generating elements 400, and an electric connection part (not shown) that is electrically connected to the electric connection substrate are disposed on the flow path forming substrate 100. In detail, the flow path forming substrate 100 is made of silicon, and may be thinned to a thickness of 625 μm by a grinding device.

[0027] In addition, a common flow path 132 and an individual flow path 134 for distributing liquid and a recess 142 for accommodating an adhesive 200 are formed in the flow path forming substrate 100. In detail, in order to form the recess 142 for accommodating the adhesive 200 or the common flow path 132 and the individual flow paths 134 for distributing liquid, anisotropic etching is performed using the Bosch process, which is a type of reactive ion etching, or TMAH, KOH, or the like. The Bosch process is capable of forming an etching groove perpendicular to the flow path forming substrate 100 by alternately performing coating and etching. Furthermore, blind holes can be formed and the flow path forming substrate 100 can be thinned by back grinding or CMP to allow penetration.

[0028] In detail, a resist is patterned from the lower surface 112 of the flow channel forming substrate 100 using a photolithography technique, and then dry etching is performed using a Bosch process. For example, when the common flow channel 132 is processed to a depth of 475 μm, the recess 142 can be processed to a depth of 250 to 300 μm. The reason why the recess 142 is shallower than the common flow channel 132 is due to the influence of a microloading effect caused by the difference in the opening area. In addition, the recess 142 can be formed by performing patterning and etching simultaneously with the common flow channel 132, but when the volume of the recess 142 is to be adjusted individually, the common flow channel 132 and the recess 142 can also be patterned and etched individually.

[0029] Similarly, the individual flow paths 134 are formed on the upper surface 111 of the flow path forming substrate 100, and the common flow path 132 and the individual flow paths 134 are connected to each other.

[0030] The support substrate 300 is made of silicon and has a thickness of 725 μm. A resist is patterned from a fourth surface 312 opposite to a third surface 311 bonded to the flow path forming substrate 100 using photolithography technology in the same manner as the flow path forming substrate 100, and blind holes are processed to a depth of 320 μm by dry etching using the Bosch process. Thereafter, the substrate is thinned to 300 μm by back grinding and CMP from the third surface 311, and the blind holes are penetrated to form a pitch conversion flow path 320 connected to the common flow path 132.

[0031] Next, a substrate for adhesive transfer was prepared, and a benzocyclobutene solution was spin-coated to a thickness of 7 μm as the adhesive 200. A PET film was used as the substrate for transfer. After coating, a bake treatment was performed at 100° C. for 5 minutes to volatilize the solvent. The adhesive formed on the substrate for transfer was brought into contact with the lower surface 112 of the flow path forming substrate 100 while applying heat, thereby transferring the adhesive 200 to the flow path forming substrate 100, and the thickness after transfer to the flow path forming substrate 100 was 2.5 μm.

[0032] Also, the flow path forming substrate 100 and the support substrate 300 are aligned using a bonding alignment device and heated in a vacuum to bond them. For example, bonding may be performed at a vacuum level of 100 Pa or less and a temperature of 150° C. When the adhesive overflowing into the common flow path 132 after bonding was checked, the thickness of the adhesive overflowing from the partition wall 136 forming the common flow path 132 was equal to or less than the thickness of the adhesive overflowing from the other parts of the common flow path 132.

[0033] After the flow path forming substrate 100 and the support substrate 300 are bonded and cooled, they are removed from the apparatus and heat treated in an oven in a nitrogen atmosphere at 250° C. for 1 hour to harden the adhesive.

[0034] Next, a negative photosensitive resin dissolved in a PGMEA solvent is spin-coated onto a PET film, dried at 100°C in an oven to form a dry film, which is then transferred to the upper surface 111 of the flow path forming substrate 100, and the PET film is peeled off to form a photosensitive resin layer. The photosensitive resin layer is exposed to a pattern that will become the flow path, and then PEB is performed to create a latent image. Next, a dry film is laminated in the same manner, and a pattern that will become the nozzle is exposed, and then PEB is performed to develop the flow path and nozzle together, completing a wafer for a liquid ejection head.

[0035] A wafer for a liquid ejection head is manufactured by forming multiple modified layers inside a silicon substrate in the thickness direction of the substrate (flow path forming substrate 100 or support substrate 300) using stealth dicing with a laser, and by applying an external force to the wafer, cracks progress between the modified portions, allowing the wafer to be fractured and a liquid ejection substrate to be obtained.

[0036] (Embodiment 2) FIG. 6 is a diagram showing a liquid ejection substrate according to a second embodiment of the present disclosure, and shows the liquid ejection substrate from the support substrate side without the support substrate. FIG. 7 is an enlarged view of part C in FIG. 6. As shown in FIGS. 6 and 7, the corners 133e provided at the end 133 of the common flow path 132 are arranged on a circumference with the width R of the common flow path 132 as a diameter. In detail, the end 133 of the common flow path 132 in this embodiment is provided with 19 corners 133e, and the corners 133e are arranged at equal intervals, and therefore the angle of one corner is greater than 90 degrees. As a result, the end 133 has an approximately semicircular shape. And each corner 133e is formed at an angle greater than 90 degrees, and therefore, when the flow path forming substrate 100 is bonded to the support substrate 300 via the adhesive 200, it is possible to prevent the adhesive 200 from creeping up to the corners 133e and to disperse the creeping up. As a result, the adhesive 200 can be further prevented from creeping up into the corners 133e due to surface tension, the adhesive 200 does not clog the individual flow paths 134, and the liquid ejection substrate 10 can be obtained with a high yield.

[0037] In this embodiment, the angle θ1 of the corner 133e closest to the individual flow path 134 is 170°.

[0038] Fig. 8 is a perspective view showing a liquid ejection head according to an embodiment of the present disclosure. As shown in Fig. 8, the liquid ejection head 3 is formed by joining a plurality of liquid ejection substrates 10 having the above-mentioned configuration. In detail, the liquid ejection head 3 is a line-type liquid ejection head in which 17 liquid ejection substrates 10 capable of ejecting ink are arranged in a straight line (arranged in-line). The liquid ejection head 3 includes a signal input terminal and a power supply terminal electrically connected to each liquid ejection substrate 10 via a flexible wiring substrate 40 or the like.

[0039] 9 is a perspective view that shows a schematic diagram of an inkjet recording apparatus according to an embodiment of a liquid ejection device. The inkjet recording apparatus 1000 is equipped with liquid ejection heads 3 that eject cyan (C), magenta (M), yellow (Y) and black (Bk) inks. The recording apparatus 1000 records an image on the recording medium P by ejecting ink from these liquid ejection heads 3 onto the recording medium P in accordance with recording data. In the figure, the X direction is the transport direction of the recording medium P, the Y direction is the width direction of the recording medium, and the Z direction is the vertical upward direction.

[0040] The liquid ejection device is not limited to the above-mentioned recording device. For example, the liquid ejection device may be a single-function printer having only a recording function, or a multifunction printer having multiple functions such as a recording function, a FAX function, and a scanner function. The liquid ejection device may also be a manufacturing device for manufacturing color filters, electronic devices, optical devices, microstructures, etc. using a predetermined recording method, or a microbubble generating device.

[0041] (Other embodiments) It is clear from the above description that any combination of the first and second embodiments described above is included in the embodiments of the present invention as long as it is not contrary to the spirit of the present invention.

[0042] The present disclosure includes configurations typified by the following liquid ejection head and liquid ejection device examples.

[0043] <Configuration 1> A liquid ejection head including a liquid ejection substrate for ejecting liquid, the liquid ejection substrate includes a flow path forming substrate and a support substrate bonded to the flow path forming substrate via an adhesive, the flow channel forming substrate has a common flow channel communicating with the flow channel formed in the support substrate and an individual flow channel communicating with the common flow channel, A liquid ejection head, wherein an angle of the corner closest to the individual flow passage among the corners at the end of the common flow passage is greater than 90°.

[0044] <Configuration 2> The liquid ejection head according to configuration 1, wherein the number of the corners is four or more.

[0045] <Configuration 3> The liquid ejection head described in configuration 2, wherein the four or more corners are curved, and among the four or more corners, the corner closest to the individual flow path has the largest radius of curvature.

[0046] <Configuration 4> The liquid ejection head according to configuration 1, wherein the corner portion is disposed on a circumference of a circle having a diameter equal to the width of the common flow path at an end portion of the common flow path.

[0047] <Component 5> The liquid ejection head according to configuration 4, wherein the corners are multiple and the multiple corners are arranged at equal intervals.

[0048] <Component 6> A liquid ejection head including a liquid ejection substrate for ejecting liquid, the liquid ejection substrate includes a flow path forming substrate and a support substrate bonded to the flow path forming substrate via an adhesive, the flow channel forming substrate has a common flow channel communicating with the flow channel formed in the support substrate and an individual flow channel communicating with the common flow channel, A liquid ejection device comprising a liquid ejection head, the angle of which of the corners at the end of the common flow path that is closest to the individual flow path is greater than 90°, and the liquid ejection head ejects ink onto a recording medium to perform recording. [Explanation of symbols]

[0049] 10 Liquid discharge board 100 Flow path forming substrate 132 Common Channel 133 End 133a Corner 133b Corner 133c Corner 133d Corner 200 Adhesive 300 Support substrate

Claims

1. A liquid ejection head including a liquid ejection substrate for ejecting liquid, the liquid ejection substrate includes a flow path forming substrate and a support substrate bonded to the flow path forming substrate via an adhesive, the flow channel forming substrate has a common flow channel communicating with the flow channel formed in the support substrate and an individual flow channel communicating with the common flow channel, A liquid ejection head, wherein an angle of the corner closest to the individual flow passage among the corners at the end of the common flow passage is greater than 90°.

2. 2. The liquid ejection head according to claim 1, wherein the number of the corners is four or more.

3. The liquid ejection head according to claim 2 , wherein the four or more corners are curved, and the radius of curvature of the corner closest to the individual flow path among the four or more corners is the largest.

4. The liquid ejection head according to claim 1 , wherein the corners are arranged on a circumference of a circle having a diameter equal to the width of the common flow path at an end of the common flow path.

5. The liquid ejection head according to claim 4 , wherein the corners are a plurality of corners, the plurality of corners being disposed at equal intervals.

6. A liquid ejection head including a liquid ejection substrate for ejecting liquid, the liquid ejection substrate includes a flow path forming substrate and a support substrate bonded to the flow path forming substrate via an adhesive, the flow channel forming substrate has a common flow channel communicating with the flow channel formed in the support substrate and an individual flow channel communicating with the common flow channel, A liquid ejection device comprising a liquid ejection head, the angle of which of the corners at the end of the common flow path that is closest to the individual flow path is greater than 90°, and characterized in that the liquid ejection head ejects ink onto a recording medium to perform recording.

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