Liquid ejecting head and liquid ejecting apparatus

Abstract

The invention relates to a liquid ejecting head and a liquid ejecting apparatus. A liquid ejecting head includes a liquid ejecting substrate for ejecting a liquid, in which the liquid ejecting substrate includes a flow substrate and a support substrate bonded to the flow substrate via an adhesive, the flow substrate including a common flow path communicating with a flow path formed in the support substrate and an independent flow path communicating with the common flow path; among the corners of the ends of the common flow path, the angle of the corner closest to the individual flow path is greater than 90 DEG.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection apparatus, and more particularly, to a technology for laminating and bonding a plurality of substrates included in the liquid ejection head to one another. Background Art

[0002] There is a liquid ejection head formed by stacking a flow path substrate on a support substrate, in which a flow channel for supplying a liquid such as ink to an ejection port is formed. Japanese Patent Laid-Open No. 2023-61022 describes bonding the stacked substrates by using an adhesive. Specifically, when the adhesive layer is transferred to the substrate, the adhesive is suppressed from being squeezed out of the bonding portion by controlling the undulation of the adhesive layer.

[0003] However, even in the case where there is a slight extrusion of the adhesive, the adhesive will extrude onto the wall surface of the partition wall of the flow channel forming the flow path substrate or onto the supporting substrate. The adhesive especially climbs on the corner formed by two adjacent edges of the supporting substrate and the partition wall. In the case where the angle of the corner is an acute angle or a right angle, the adhesive is more likely to climb on the corner due to the capillary force caused by the surface tension of the adhesive. Then, in the case where the amount of adhesive climbing on the corner of the partition wall of the flow path substrate, etc. is large, the independent flow path connected to the common flow path formed in the flow path substrate is blocked by the adhesive that has climbed, which will hinder the supply of liquid from the independent flow path to the energy generating element, thereby causing an adverse effect that may damage the liquid injection performance of the liquid injection head. Summary of the invention

[0004] The liquid injection head disclosed herein includes: a liquid injection substrate for injecting liquid, wherein the liquid injection substrate includes a flow path substrate and a supporting substrate bonded to the flow path substrate via an adhesive, the flow path substrate includes a common flow path connected to a flow channel formed in the supporting substrate and an independent flow path connected to the common flow path, and among the corners at the end of the common flow path, the angle of the corner closest to the independent flow path is greater than 90°.

[0005] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a cross-sectional perspective view showing a portion of a liquid ejection substrate included in a liquid ejection head according to a first embodiment of the present disclosure;

[0007] Figure 2 yes Figure 1 a cross-sectional view of a portion of the liquid ejection substrate;

[0008] Figure 3 Observed from the bottom side Figure 1A schematic diagram of a flow path substrate of the liquid ejection substrate shown;

[0009] Figure 4 yes Figure 3 Enlarged view of part A in the middle;

[0010] Figure 5 yes Figure 4 Enlarged view of middle part B;

[0011] Figure 6 is a schematic diagram for explaining a liquid ejection substrate according to a second embodiment of the present disclosure;

[0012] Figure 7 yes Figure 6 Enlarged view of the middle C part;

[0013] Figure 8 is a perspective view showing a liquid ejection head according to an embodiment of the present disclosure;

[0014] Fig. 9 is a perspective view schematically showing an inkjet printing apparatus according to an embodiment of a liquid ejecting apparatus. DETAILED DESCRIPTION

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the size, material, shape, relative arrangement, etc. of the components of the embodiments described below may be appropriately changed according to the configuration of the liquid ejection substrate, etc. of the liquid ejection head to which the present disclosure is applicable and various conditions. The scope of the present disclosure is not limited to the embodiments described below.

[0016] (Example 1)

[0017] Figure 1 is a cross-sectional perspective view showing a portion of a liquid ejection substrate included in a liquid ejection head according to the present embodiment, Figure 2 yes Figure 1 A cross-sectional view of a portion of a liquid ejection substrate is shown. Figure 1 and Figure 2 As shown, the liquid ejection substrate 10 includes a flow path substrate 100, a support substrate 300 bonded to the flow path substrate 100 via an adhesive 200, and an energy generating element 400 disposed on the flow path substrate 100 and configured to generate energy for ejecting liquid.

[0018] The liquid ejection substrate 10 of the present embodiment is mounted on an inkjet printing device as a liquid ejection device for use, and ejects ink as a liquid.

[0019] On the upper surface 111 of the flow path substrate 100, the flow path layer 150 and the nozzle layer 160 are stacked in a range corresponding to their formation portions to form the ejection port 120, the pressure chamber 118, etc. The lower surface 112 of the flow path substrate 100 is bonded to the support substrate 300 via the adhesive 200. In addition, a pitch changing flow path 320 is formed in the support substrate 300, and the pitch changing flow path is connected to the common flow path 132 formed in the flow path substrate 100.

[0020] like Figure 2 As shown, the liquid ejection substrate 10 according to the embodiment described above is divided into a flow channel region 130 and an adhesion region 140 in a direction orthogonal to the arrangement direction of the ejection ports 120 .

[0021] In the flow channel region 130, there are a common flow path 132 for supplying liquid to the energy generating element 400, an independent flow path 134 communicating with the common flow path 132, and a pressure chamber 118 provided with the energy generating element 400. The liquid flows from the common flow path 132 through the independent flow path 134 to reach the pressure chamber 118, and the energy generating element 400 generates energy to eject the liquid that has reached the pressure chamber 118 from the ejection port 120 communicating with the pressure chamber 118.

[0022] In addition, the common flow path 132 includes a supply flow channel 132a for supplying liquid to the energy generating element 400 and a recovery flow channel 132b for recovering liquid that has been supplied to the energy generating element 400 but has not been used for ejection. As described above, 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 via the adhesive 200.

[0023] Reference again Figure 1 and Figure 2 The bonding area 140 is an area in the flow path substrate 100 where the flow channel is adjacent only on one side. That is, the portion where the lower surface 112 of the flow path substrate 100 is bonded to the support substrate 300 in this area is an area where the ink does not flow back and forth through the bonding portion. In this area, a plurality of recesses (grooves) 142 for receiving the adhesive 200 are provided on the lower surface 112 side of the flow path substrate 100.

[0024] Note that the energy generating element 400 of the present embodiment is a heating resistor element, but may be another structure, for example, may be a piezoelectric element. In addition, wiring for supplying power to the energy generating element 400, pads for electrode connection, etc. are not shown. For the adhesive 200, it is advantageous to use a material having high adhesion to the flow path substrate 100 and the support substrate 300, preferably a material with a small amount of bubbles and the like mixed in and having high coating properties, preferably a low-viscosity material that can easily 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 polyurethane resin.

[0025] The method for curing the adhesive 200 may be a thermosetting method or an ultraviolet delayed curing method. Note that in the case where the flow path substrate 100 or the support substrate 300 has ultraviolet transmittance, an ultraviolet curing method may also be used as a method for curing the adhesive 200.

[0026] In addition, the method for applying the adhesive 200 includes an adhesive transfer method performed on the substrate used. Specifically, a transfer substrate is prepared, and the adhesive 200 is thinly and evenly applied to the transfer substrate by a spin coating method or a slit coating method. Afterwards, the lower surface 112 of the flow path substrate 100 is contacted with the adhesive 200 thus applied, so that the adhesive 200 can be transferred only to the lower surface 112 of the flow path substrate 100. The size of the transfer substrate is advantageously equal to or greater than the size of the flow path substrate 100. As the transfer substrate, a film of silicon, glass, PET, PEN, PI, etc. is advantageously used. In addition, the method of directly forming the adhesive 200 on the flow path substrate 100 includes screen printing and dispensing coating. Although the above description is performed by using the flow path substrate 100, as the same coating method, the adhesive 200 can be applied to the third surface 311 of the support substrate 300 for bonding with the flow path substrate 100.

[0027] Note that the support substrate 300 and the flow path substrate 100 coated with the adhesive 200 are bonded by heating the support substrate 300 and the flow path substrate 100 to a predetermined temperature in a bonding device and pressurizing them for a predetermined time and pressure. These bonding parameters are appropriately set according to the bonding material. In addition, in order to suppress the mixing of bubbles into the bonding portion between the flow path substrate 100 and the support substrate 300, it is preferred to bond the flow path substrate 100 and the support substrate 300 in a vacuum.

[0028] In the case where the adhesive 200 is a thermosetting type, the adhesive 200 may be heated in the bonding device until it is cured. The curing of the adhesive 200 may be promoted by removing the substrate bonding product after bonding and then heating the substrate bonding product alone in an oven. On the other hand, in the case where the adhesive 200 is an ultraviolet ray delayed type, the adhesive 200 is irradiated with a predetermined amount of ultraviolet rays before bonding the support substrate 300 to the flow path substrate 100, and then the support substrate 300 is bonded to the flow path substrate 100. After bonding the support substrate 300 to the flow path substrate 100, it is preferred to further heat the substrate bonding product to sufficiently promote the curing of the adhesive 200. In the case where the adhesive 200 is an ultraviolet ray curing type, after bonding the flow path substrate 100 and the support substrate 300, the adhesive 200 is irradiated with a predetermined amount of ultraviolet rays through the substrate having ultraviolet transmittance (the flow path substrate 100 or / and the support substrate 300) to cure the adhesive 200. After the support substrate 300 is bonded to the flow path substrate 100 , it is preferable to further heat the substrate bonding product to sufficiently promote the curing of the adhesive 200 .

[0029] Figure 3 Observed from the bottom side Figure 1 The schematic diagram of the flow path substrate 100 of the liquid ejection substrate 10 is shown. Figure 4 yes Figure 3 A magnified view of part A. Figure 3 and Figure 4 As shown, the common flow path 132 extends substantially parallel to the longitudinal end 121a of the flow path substrate 100, and the opening ends of the plurality of independent flow paths 134 are arranged parallel to the longitudinal direction of the common flow path 132. Thus, each independent flow path 134 is connected to the corresponding common flow path 132 and communicates therewith.

[0030] The end portion 133 of each common flow path 132 has four corner portions 133a, 133b, 133c and 133d (see Figure 5 ). The corner portion in this specification is a portion consisting of the inner wall surface of the common flow path 320 extending in a direction intersecting the bonding surface of the flow path substrate 100 bonded to the support substrate 300. Corner portions 133a, 133b, 133c, and 133d are provided in two opposite end portions 133 of the common flow path 132. Although this embodiment shows an example in which four corner portions 133a, 133b, 133c, and 133d are provided in one end portion 133, it is preferred to provide four or more corner portions 133a, 133b, 133c, and 133d, and the number of corner portions is not limited to four.

[0031] Figure 5 yes Figure 4 The enlarged view of the middle B. Figure 5As shown, in the liquid ejection head of the present embodiment, in the case where the angles of the corners 133a, 133b, 133c, and 133d formed in the end 133 of the common flow path 132 are represented by θ1, θ2, θ3, and θ4, respectively, the angle θ1 of the corner 133a closest to the independent flow path 134 is set to an angle greater than 90°. It can also be said that the angle θ1 of the corner 133a in the plane shape of the common flow path 132 is set to an angle greater than 90° as viewed from the direction perpendicular to the bonding surface of the flow path substrate 100 bonded to the support substrate 300. In the present embodiment, the angles θ2, θ3, and θ4 of the corners 133b, 133c, and 133d are also set to angles greater than 90°. In addition, in the present embodiment, two sides constituting each of the corners 133a, 133b, 133c, and 133d are connected by a curve to form the vertex of the corner into a curved shape. In the case where the radii of curvature of the above-mentioned curve of the curved shape are represented by R1, R2, R3 and R4, respectively, these values ​​correspond to the above-mentioned angles θ1, θ2, θ3 and θ4, respectively. For example, in the case where the angle θ1 of the corner 133a closest to the independent flow path 134 is the largest, the radius of curvature R1 is also the maximum value. By the configuration of the above-mentioned corners, when the flow path substrate 100 is bonded to the support substrate 300 via the adhesive 200, the capillary force of the adhesive 200 is reduced, so that the adhesive 200 can be suppressed from climbing on the corners 133a, 133b, 133c and 133d of the common flow path 132. In particular, the configuration in which the angle θ1 of the corner 133a closest to the independent flow path 134 is greater than 90° makes it possible to prevent the independent flow path 134, which is more easily reached by the adhesive 200, from being blocked by the adhesive 200.

[0032] In addition, by setting a plurality of corners 133a, 133b, 133c and 133d in the end portion 133 of the common flow path 132, when the flow path substrate 100 is bonded to the supporting substrate 300 via the adhesive 200, the climbing of the adhesive 200 is dispersed to the corners 133a, 133b, 133c and 133d, so that the climbing of the adhesive 200 in the corners 133a, 133b, 133c and 133d due to capillary force can be further suppressed, so that the independent flow path 134 is not blocked by the adhesive 200 and the liquid injection substrate 10 with a high yield can be obtained.

[0033] Regarding the manufacturing method of the liquid ejection substrate 10 in the present embodiment, an energy generating element 400 for ejecting liquid and formed of TaSiN, a circuit (not shown) for driving the energy generating element 400, and an electrical connection portion (not shown) electrically connected to an electrical connection substrate are provided on the flow path substrate 100. Specifically, the flow path substrate 100 is formed of silicon and can be thinned to a substrate thickness of 625 μm by using a grinding device.

[0034] In addition, a common flow path 132 and an independent flow path 134 for allowing liquid to flow through, and a recess 142 for accommodating an adhesive 200 are formed in the flow path substrate 100. Specifically, in order to form the recess 142 for accommodating the adhesive 200 or the common flow path 132 and independent flow path 134 for allowing liquid to flow through, anisotropic etching is performed by a Bosch process, TMAH, KOH, or the like, which is a type of reactive ion etching. The Bosch process can form an etching groove perpendicular to the flow path substrate 100 by alternately performing coating and etching. In addition, a non-through hole can be formed, and the non-through hole can be penetrated by thinning the flow path substrate 100 by back grinding or CMP.

[0035] Specifically, the resist is patterned from the lower surface 112 of the flow path substrate 100 by using photolithography technology, and processed by dry etching using the Bosch process; for example, when the common flow path 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 path 132 is due to the influence of the micro-load effect caused by the difference in opening area. In addition, the recess 142 can be formed by patterning and etching simultaneously with the common flow path 132. In the case of adjusting the capacity of the recess 142 separately, the common flow path 132 and the recess 142 can be patterned and etched separately.

[0036] Similarly, the individual flow paths 134 are processed from the upper surface 111 of the flow path substrate 100 so that the common flow path 132 and the individual flow paths 134 communicate with each other.

[0037] The support substrate 300 is formed of silicon, and the thickness of the support substrate 300 is 725 μm. In the same manner as the flow path substrate 100, the resist is patterned from the fourth surface 312 opposite to the third surface 311 bonded to the flow path substrate 100 by using photolithography technology, and the non-through hole is processed to a depth of 320 μm by dry etching using the Bosch process. Thereafter, the substrate is thinned to 300 μm from the third surface 311 by back grinding or CMP to penetrate the non-through hole, thereby forming the pitch conversion flow channel 320 connected to the common flow path 132.

[0038] Next, an adhesive transfer substrate was prepared, and a benzocyclobutene solution was spin-coated as an adhesive 200 to a thickness of 7 μm. A PET film was used as the transfer substrate. In addition, in order to evaporate the solvent after coating, a baking treatment was performed at 100° C. for 5 minutes. The adhesive 200 was transferred to the flow path substrate 100 by bringing the adhesive formed on the transfer substrate into contact with the lower surface 112 of the flow path substrate 100 while heating. The thickness after transfer to the flow path substrate 100 was 2.5 μm.

[0039] In addition, by using a bonding alignment device, the flow path substrate 100 and the support substrate 300 are heated in a vacuum to be bonded while aligning the flow path substrate 100 and the support substrate 300 with each other. For example, bonding can be performed at a vacuum degree of less than 100 Pa and a temperature of 150° C. When it is checked that the adhesive is extruded into the common flow path 132 after bonding, the thickness of the adhesive extruded on the partition wall 136 forming the common flow path 132 is similar to or smaller than the thickness of the other adhesive extruded in the common flow path 132.

[0040] After bonding and cooling, the flow channel substrate 100 and the support substrate 300 were taken out of the device and then heat-treated at 250° C. for 1 hour in an oven in a nitrogen atmosphere to cure the adhesive.

[0041] Next, a PET film is spin-coated with a solution obtained by dissolving a negative photosensitive resin in a PGMEA solvent, and dried in an oven at 100°C to form a dry film. The dry film is transferred to the upper surface 111 of the flow path substrate 100, and the PET film is peeled off to form a photosensitive resin layer. The pattern that will become the flow path is exposed on the photosensitive resin layer, and then PEB is performed to form a latent image state. Subsequently, the dry film is similarly laminated and the pattern that will become the nozzle is exposed, and then PEB is performed to simultaneously develop the flow path and the nozzle, thereby completing a wafer for a liquid ejection head.

[0042] Stealth cutting using laser is performed on a wafer for a liquid jet head to form a plurality of modified layers inside a silicon substrate along the thickness direction of the substrate (the flow path substrate 100 or the support substrate 300). External force is applied to the wafer to generate cracks between the modified portions to separate the wafer, thereby obtaining a liquid jet substrate.

[0043] (Example 2)

[0044] Figure 6 is a schematic diagram showing a liquid ejection substrate according to a second embodiment of the present disclosure, showing the liquid ejection substrate from a supporting substrate side while omitting the supporting substrate. Figure 7 yes Figure 6 The enlarged view of the middle C part. Figure 6 and Figure 7As shown, the corner 133e provided in the end 133 of the common flow path 132 is provided on a circumference having a diameter equal to the width R of the common flow path 132. Specifically, 19 corners 133e are provided in the end 133 of the common flow path 132 of the present embodiment, and the corners 133e are provided at equal intervals. Therefore, the angle of each corner 133e is greater than 90°. In this way, the end 133 is roughly semicircular. Then, each corner 133e is formed at an angle greater than 90°, which prevents the adhesive 200 from climbing on the corner 133e and can disperse the climbing when the flow path substrate 100 is bonded to the support substrate 300 via the adhesive 200. As a result, the climbing of the adhesive 200 caused by the surface tension in the corner 133e can be further suppressed, so that the independent flow path 134 will not be blocked by the adhesive 200 and the liquid injection substrate 10 with a high yield can be obtained.

[0045] In addition, in the present embodiment, the angle θ1 of the corner portion 133 e closest to the independent flow path 134 is 170°.

[0046] Figure 8 1 is a perspective view showing a liquid ejection head according to an embodiment of the present disclosure. Figure 8 As shown, the liquid ejection head 3 is formed by bonding a plurality of liquid ejection substrates 10 each having the above-mentioned configuration. Specifically, the liquid ejection head 3 is a line-type liquid ejection head in which 17 liquid ejection substrates 10 each capable of ejecting ink are arranged along a straight line (linear). The liquid ejection head 3 includes a signal input terminal and a power supply terminal, which are electrically connected to each liquid ejection substrate 10 via a flexible wiring substrate 40 or the like.

[0047] Fig. 9 1 is a perspective view schematically showing an inkjet printing apparatus according to an embodiment of a liquid ejection apparatus. The inkjet printing apparatus 1000 includes liquid ejection heads 3 that eject cyan (C), magenta (M), yellow (Y), and black (Bk) inks, respectively. The printing apparatus 1000 prints an image on a printing medium P by ejecting ink from these liquid ejection heads 3 onto the printing medium P according to print data. Fig. 9 In the figure, the X direction is the conveying direction of the printing medium P, the Y direction is the width direction of the printing medium P, and the Z direction is the vertical downward direction.

[0048] Note that the liquid ejection device is not limited to the printing device described above. The liquid ejection device may be, for example, a single-function printer having only a printing function, or may be a multifunction printer having multiple functions such as a printing function, a fax function, a scanning function, etc. In addition, the liquid ejection device may be a manufacturing device for manufacturing a color filter, an electronic device, an optical device, a microstructure, etc. according to a predetermined printing method, or may be a microbubble generating device, etc.

[0049] According to the above structure, when the flow path substrate is bonded to the supporting substrate via an adhesive, the capillary force caused by the surface tension of the adhesive in the corners of the common flow path in the liquid ejection head can be suppressed from climbing into the corners, and the independent flow path can be prevented from being blocked by the adhesive.

[0050] (Other embodiments)

[0051] As to the above-mentioned first to second embodiments, it is also apparent from the above description that any combination of these embodiments is included in the embodiments of the present disclosure unless these combinations are inconsistent with the gist of the present disclosure.

[0052] Although the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications and equivalent structures and functions.

Claims

1. A liquid ejection head, comprising: A liquid ejection substrate for ejecting liquid, wherein The liquid ejection substrate includes a flow path substrate and a support substrate, and the support substrate is bonded to the flow path substrate via an adhesive. The flow path substrate includes a common flow path communicating with the flow channel formed in the support substrate and an independent flow path communicating with the common flow path, and Among the corners at the end of the common flow path, the angle of the corner closest to the independent flow path is larger than 90°.

2. The liquid ejecting head according to claim 1, wherein: One end portion includes four or more corner portions.

3. The liquid ejecting head according to claim 2, wherein: Each of the four or more corners has a curved shape, and Among the four or more corners, the curvature radius of the corner closest to the independent flow path is the largest.

4. The liquid ejecting head according to claim 1, wherein: In the end portion of the common flow path, each corner portion is arranged on a circumference having a diameter equal to the width of the common flow path.

5. The liquid ejecting head according to claim 4, wherein: An end portion includes a plurality of corners, and The plurality of corner portions are arranged at equal intervals.

6. The liquid ejecting head according to claim 1, wherein: When viewed from a direction perpendicular to the surface of the liquid ejecting substrate, the angle of the corner closest to the independent flow channel is larger than 90°.

7. The liquid ejecting head according to claim 1, wherein: The common flow path communicates with the plurality of independent flow paths.

8. The liquid ejecting head according to claim 7, wherein: The plurality of independent flow paths are arranged in parallel with a longitudinal direction of the common flow path.

9. The liquid ejecting head according to claim 8, wherein: In a direction orthogonal to the longitudinal direction of the common flow path, the center of the common flow path and the center of each independent flow path are not aligned with each other.

10. A liquid ejection device, comprising: A liquid ejection head includes a liquid ejection substrate for ejecting liquid, wherein: The liquid ejection substrate includes a flow path substrate and a support substrate bonded to the flow path substrate via an adhesive. The flow path substrate includes a common flow path communicating with the flow channel formed in the support substrate and an independent flow path communicating with the common flow path, and Among the corners at the end of the common flow path, the angle of the corner closest to the independent flow path is greater than 90°, wherein, The liquid ejecting apparatus performs printing by ejecting ink from a liquid ejecting head onto a printing medium.

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