Liquid ejection head and manufacturing method thereof

Abstract

To provide a liquid discharge head which prevents flowing from a coating position of a sealing material, and has high electric reliability.SOLUTION: A liquid discharge head has an electric board including an element for discharging a liquid, a flow channel formation member having a pressure chamber and a discharge port which communicates with the pressure chamber and discharges the liquid, and a pad array where a plurality of pads electrically connected to the element are arrayed along one side of the substrate, on a first surface of a substrate, an electric wiring board connected to the pad through an electric connection part, and a sealing material arranged on the first surface of the substrate so as to cover the electric connection part, wherein the flow channel formation member has an opening, and the pad is positioned in the opening, when the element substrate is viewed in plan view.SELECTED DRAWING: Figure 17

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head and a method for manufacturing the same. [Background technology]

[0002] A liquid ejection head provided in a liquid ejection device such as an inkjet printer has an element substrate equipped with elements that pressurize the liquid, and a nozzle plate equipped with ejection ports. The pressurized liquid is ejected from the ejection ports as droplets to the outside of the head. The element substrate on which the elements are formed is formed with electrodes (such as electrode pads) that are electrically connected to an electrical wiring board to supply power from an external source to drive the elements. Electrical connections, such as wires and inner leads that connect the electrodes to the electrical wiring board, are sealed with a sealant such as a resin material to prevent ink from adhering to them. The electrical connections are covered by applying a sealant to the electrical connections and then curing the applied sealant by heating or other means.

[0003] However, if the sealant flows from the application position on the element substrate, it may not be able to adequately cover the electrical connections. Therefore, some liquid ejection heads have a member on the element substrate that acts as a wall to prevent the sealant from flowing. For example, Patent Document 1 discloses a liquid ejection head in which an insulating member is disposed between an electrode pad row on the element substrate and the edge of the substrate corresponding to the electrode pad row. The insulating member in Patent Document 1 is made of the same material as an adhesion layer formed between the element substrate and the nozzle plate to improve adhesion between the element substrate and the nozzle plate, and is formed simultaneously by photolithography. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-733 Summary of the Invention [Problem to be solved by the invention]

[0005] In the liquid ejection head described in Patent Document 1, an adhesive layer is used to form a wall to prevent the sealant from flowing outside the element substrate. However, because the adhesive layer is generally low in height, if the amount of sealant applied increases, it may overflow the wall and spill outside the element substrate. If the sealant flows, bubbles may be trapped within the sealant, and the bubbles may expand when the sealant is thermally cured, exposing the electrical connections.

[0006] In view of the above problems, the present invention aims to provide a liquid ejection head with high electrical reliability by forming a wall for suppressing the flow of sealant using a flow path forming member for forming a flow path on an element substrate, thereby making it easier to prevent the sealant from flowing away from the application position. [Means for solving the problem]

[0007] To achieve the above object, the present invention provides a liquid ejection head having an element substrate on a first surface of a substrate, the element substrate having an element for ejecting liquid, a flow path forming member having a pressure chamber and an ejection port communicating with the pressure chamber and ejecting liquid, and a pad row in which a plurality of pads electrically connected to the element are arranged along one side of the substrate, an electrical wiring board connected to the pads via electrical connection parts, and a sealing material arranged on the first surface of the substrate so as to cover the electrical connection parts, and when the element substrate is viewed in a plane, the flow path forming member has an opening and the pad is located within the opening. Alternatively, the liquid ejection head comprises an element substrate provided on a first surface of a substrate with elements for ejecting liquid, a flow path forming member having pressure chambers and ejection ports communicating with the pressure chambers to eject liquid, and a pad row in which a plurality of pads electrically connected to the elements are arranged along one side of the substrate; an electric wiring board connected to the pads via electrical connection parts; and a sealing material arranged on the first surface of the substrate so as to cover the electrical connection parts, wherein, when viewed from a direction perpendicular to the substrate, a structure made of the same material as the flow path forming member is provided between the one side and the pad row, and the height of the structure in the direction perpendicular to the substrate is 3 μm or more and 25 μm or less. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a liquid ejection head that is electrically reliable and that prevents the sealing material from flowing away from the application position. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a liquid ejection apparatus according to an embodiment of the present invention. [Figure 2] 1 is a conceptual diagram illustrating a control system according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram showing a circulation path of a liquid according to an embodiment of the present invention. [Figure 4] 1 is a perspective view showing a liquid ejection head according to an embodiment of the present invention. [Figure 5] FIG. 1 is an exploded perspective view of a liquid ejection head according to an embodiment of the present invention. [Figure 6] FIG. 2 is a plan view of the flow path member according to the embodiment of the present invention. [Figure 7] 1A and 1B are a perspective view and a cross-sectional view of a flow path member and a discharge module according to an embodiment of the present invention. [Figure 8] 1A and 1B are a perspective view and an exploded perspective view of a dispensing module according to an embodiment of the present invention; [Figure 9] FIG. 2 is a plan view of an element substrate according to an embodiment of the present invention. [Figure 10] FIG. 2 is a cross-sectional view of an element substrate according to an embodiment of the present invention. [Figure 11] 2A and 2B are a plan view and a cross-sectional view showing the inside of a liquid ejection head according to an embodiment of the present invention. [Figure 12] FIG. 2 is an enlarged plan view of the vicinity of an ejection port of a liquid ejection head according to an embodiment of the present invention. [Figure 13] FIG. 3 is a partially enlarged plan view of an adjacent portion of an element substrate according to an embodiment of the present invention. [Figure 14] 1A and 1B are a plan view of an element substrate and a cross-sectional view of a discharge module in a conventional example. [Figure 15] 2A and 2B are a plan view of an element substrate and a cross-sectional view of a discharge module according to the first embodiment. [Figure 16] 10A and 10B are a plan view of an element substrate and a cross-sectional view of a discharge module according to a second embodiment. [Figure 17] 10A and 10B are a plan view of an element substrate and a cross-sectional view of a discharge module according to a third embodiment. [Figure 18] 10A and 10B are a plan view of an element substrate and a cross-sectional view of a discharge module according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will now be described with reference to the accompanying drawings. However, the following description is not intended to limit the scope of the present invention. As an example, the present embodiment employs a thermal system in which a heat-generating element generates bubbles to eject liquid. However, the present invention can also be applied to liquid ejection heads employing a piezo system that uses a piezoelectric element as the energy-generating element for ejecting liquid, or various other liquid ejection systems. The liquid ejection head and liquid ejection device incorporating the liquid ejection head of the present invention can be used in devices such as inkjet printers, copiers, facsimiles with communication systems, and word processors with printer units. Furthermore, the liquid ejection head and liquid ejection device can be used in industrial recording devices combined with various processing devices. For example, the liquid ejection head can also be used in applications such as biochip fabrication, electronic circuit printing, and semiconductor substrate fabrication.

[0011] Although this embodiment is a liquid ejection device in which a liquid such as ink is circulated between a tank and a liquid ejection head, other configurations are also possible. For example, instead of circulating the liquid, two tanks may be provided upstream and downstream of the liquid ejection head, and the liquid may flow from one tank to the other to cause the liquid to flow within the pressure chamber. Furthermore, this embodiment is a so-called line-type (page-wide) liquid ejection head having a length corresponding to the width of the recording medium, but the present invention can also be applied to so-called serial-type liquid ejection heads that print while scanning the recording medium. An example of a serial-type liquid ejection head is one that includes one element substrate for black ink and one for color ink, but this is not limited to this. Alternatively, a short line head shorter than the width of the recording medium may be created by arranging several element substrates so that the ejection openings overlap in the direction of the ejection opening array, and this line head may be used to scan the recording medium.

[0012] (First embodiment) <Overall configuration of the device> 1 is a diagram showing an example of a liquid ejection device according to the present embodiment. The liquid ejection device according to the present embodiment is a liquid ejection device 1000 (hereinafter simply referred to as device 1000) that serves as an inkjet printer that records a color image on a recording medium 2 by ejecting yellow (Y), magenta (M), cyan (C), and black (Bk) inks. In the figure, the X direction is the transport direction of the recording medium 2, the Y direction is the width direction of the recording medium, and the Z direction is the direction that intersects the X and Y directions and is the direction in which liquid is ejected.

[0013] FIG. 1 shows an apparatus 1000 in which a liquid ejection head 3 directly applies ink to a recording medium 2 transported in the X direction. The recording medium 2 is mounted on a transport unit 1 and transported in the X direction at a predetermined speed below four liquid ejection heads 3 (3Y, 3M, 3C, 3Bk) that eject different inks. In FIG. 1, the four liquid ejection heads 3 are arranged in the X direction in the order 3Bk, 3C, 3M, 3Y, and inks are applied to the recording medium 2 in the order black, cyan, magenta, and yellow. Each liquid ejection head 3 has a plurality of ejection ports arranged in the Y direction for ejecting ink.

[0014] 1 shows cut paper as the recording medium 2, the recording medium 2 may also be continuous paper supplied from a roll of paper. Also, the recording medium is not limited to paper, and may be, for example, film.

[0015] In addition, although the present embodiment shows a liquid ejection device configured such that one liquid ejection head ejects ink of a single color, one liquid ejection head may be configured to eject ink of multiple colors, or may be configured to eject liquids other than ink, such as reaction liquids or overcoat agents.

[0016] 2 is a block diagram illustrating the control configuration of the liquid ejection device 1000. The control unit 500 is composed of a CPU and other components, and controls the entire liquid ejection device 1000 while using a RAM 502 as a work area in accordance with programs and various parameters stored in a ROM 501. The control unit 500 performs predetermined image processing on image data received from an externally connected host device 600 in accordance with the programs and parameters stored in the ROM 501, and generates ejection data that can be ejected by the liquid ejection head 3. The control unit 500 then drives the liquid ejection head 3 in accordance with this ejection data, causing it to eject ink at a predetermined frequency.

[0017] During the ejection operation by the liquid ejection head 3, the control unit 500 drives the transport motor 503 to transport the recording medium 2 in the X direction at a speed corresponding to the drive frequency. As a result, an image is recorded on the recording medium 2 in accordance with the image data received from the host device 600. Information on the use areas of the ejection ports used for ejection in the liquid ejection head 3 is stored in the ROM 501 in a rewritable manner for each liquid ejection head 3.

[0018] <Liquid circulation path> 3 is a schematic diagram showing the circulation paths of liquid in the liquid ejection device of this embodiment, and is a diagram showing the liquid ejection head 3 fluidly connected to a first circulation pump 1002, a buffer tank 1003, etc. Note that while FIG. 3 only shows the path through which ink flows in a liquid ejection head corresponding to one color of ink, the device main body 1000 is provided with circulation paths corresponding to the type of liquid, such as ink, to be ejected.

[0019] The buffer tank 1003, which serves as a sub-tank and is connected to the main tank 1006, has an air communication port (not shown) that connects the inside of the tank with the outside, and is capable of discharging air bubbles in the ink to the outside. The buffer tank 1003 is also connected to a refill pump 1005. When liquid is consumed in the liquid ejection head 3 by ejecting (discharging) ink from the ejection ports of the liquid ejection head for recording by ejecting ink or for suction recovery, the refill pump 1005 transfers the consumed ink from the main tank 1006 to the buffer tank 1003.

[0020] The first circulation pump 1002 has the role of drawing liquid from the liquid connection part 111 of the liquid ejection head 3 and flowing it into the buffer tank 1003. When the liquid ejection head 3 is driven, the first circulation pump 1002 causes a constant amount of ink to flow through the common recovery channel 212.

[0021] The negative pressure control unit 230 is provided between the second circulation pump 1004 and the liquid discharge unit 300. Even if the flow rate in the circulation system fluctuates due to differences in the duty ratio during printing, the negative pressure control unit 230 has the function of maintaining the pressure downstream (on the liquid discharge unit 300 side) at a preset constant pressure.

[0022] As shown in Fig. 3, the negative pressure control unit 230 has two pressure adjustment mechanisms, each of which is set to a different control pressure. Of the two pressure adjustment mechanisms, the relatively high pressure setting side (negative pressure control section 230H, indicated as H in Fig. 3) and the relatively low pressure setting side (negative pressure control section 230L, indicated as L in Fig. 3) are respectively connected to a common supply channel 211 and a common recovery channel 212 in the liquid ejection unit 300 via the liquid supply unit 220. The liquid ejection unit 300 is provided with the common supply channel 211, the common recovery channel 212, and individual supply channels 213a and individual recovery channels 213b that communicate with each element substrate having an ejection port. Details of the element substrate 10 will be described later. Because the individual flow paths 213 communicate with the common supply flow path 211 and the common recovery flow path 212, a portion of the liquid flowed by the second circulation pump 1004 flows from the common supply flow path 211 through the internal flow paths of the element substrate 10 to the common recovery flow path 212 (arrows in FIG. 3). This is because a pressure difference is provided between the pressure adjustment mechanism H connected to the common supply flow path 211 and the pressure adjustment mechanism L connected to the common recovery flow path 212, and the first circulation pump 1002 is connected only to the common recovery flow path 212.

[0023] In this way, in the liquid ejection unit 300, a liquid flow that passes through the common recovery channel 212 and a liquid flow that passes from the common supply channel 211 through each element substrate 10 to the common recovery channel 212 are generated. As a result, heat generated in each element substrate 10 can be discharged to the outside of the element substrate 10 by the flow from the common supply channel 211 to the common recovery channel 212. Furthermore, with this configuration, when recording is being performed with the liquid ejection head 3, ink flows can also be generated in ejection ports and pressure chambers that are not performing recording, thereby suppressing thickening of the ink in those areas. Furthermore, thickened ink and foreign matter in the ink can be discharged to the common recovery channel 212. As a result, the liquid ejection head 3 of this embodiment is capable of high-speed, high-quality recording.

[0024] <Configuration of liquid ejection head> 4(a) and 4(b) are perspective views of the liquid ejection head 3 according to this embodiment. The liquid ejection head 3 is a line-type liquid ejection head in which 17 element substrates 10 capable of ejecting ink are arranged in a straight line (arranged in-line). As shown in FIGS. 4(a) and 4(b), the liquid ejection head 3 is provided with each element substrate 10, a signal input terminal 91 electrically connected via an electric wiring board (flexible wiring board) 40 and an electric wiring board 90, and a power supply terminal 92. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the device 1000, and supply an ejection drive signal and power required for ejection to the element substrate 10, respectively. By consolidating the wiring using an electric circuit within the electric wiring board 90, the signal input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the device 1000, and supply an ejection drive signal and power required for ejection to the element substrate 10, respectively. input The number of terminals 91 and power supply terminals 92 can be made smaller than the number of element substrates 10. This reduces the number of electrical connections that need to be removed when assembling the liquid ejection head 3 to the device 1000 or when replacing the liquid ejection head 3. As shown in FIG. 4(a), a liquid connection part 111 provided on one side of the liquid ejection head 3 is connected to a liquid supply system of the device 1000. This allows ink to be supplied from the supply system of the device 1000 to the liquid ejection head 3, and ink that has passed through the liquid ejection head 3 is collected by the supply system of the device 1000. In this way, ink can circulate via the paths of the device 1000 and the paths of the liquid ejection head 3.

[0025] FIG. 5 shows an exploded perspective view of each component or unit constituting the liquid ejection head 3. The liquid ejection unit 300, liquid supply unit 220, and electrical wiring board 90 are attached to the housing 80. The liquid supply unit 220 is provided with a liquid connection 111, and a filter 221 (FIG. 3) is provided inside the liquid supply unit 220. The filter 221 communicates with each opening of the liquid connection 111 to remove foreign matter from the ink being supplied. The liquid that passes through the filter 221 is supplied to a negative pressure control unit 230 disposed above the liquid supply unit 220. The negative pressure control unit 230 is a unit comprising a pressure adjustment valve. The valves and spring members provided inside the unit significantly attenuate pressure loss changes in the supply system of the device 1000 (the supply system upstream of the liquid ejection head 3) that occur due to fluctuations in the liquid flow rate. This makes it possible to stabilize negative pressure changes downstream of the negative pressure control unit 230 (the liquid ejection unit 300 side) within a certain range. The negative pressure control unit 230 has two pressure adjustment valves built in, each set to a different control pressure, and the high-pressure side is connected to the common supply flow path 211 in the liquid ejection unit 300, and the low-pressure side is connected to the common recovery flow path 212 via the liquid supply unit 220.

[0026] The housing 80 has a liquid discharge unit support portion 81 and an electric wiring board support portion 82, and supports the liquid discharge unit 300 and the electric wiring board 90 while ensuring the rigidity of the liquid discharge head 3. The electric wiring board support portion 82 is for supporting the electric wiring board 90, and is fixed to the liquid discharge unit support portion 81 by screws. The liquid discharge unit support portion 81 is provided with openings 83 and 84 into which a joint rubber 100 is inserted. The liquid supplied from the liquid supply unit 220 is guided via the joint rubber 100 to the second flow path member 60 that constitutes the liquid discharge unit 300.

[0027] Next, the configuration of the flow path member 210 included in the liquid discharge unit 300 will be described. As shown in FIG. 5, the flow path member 210 is formed by stacking a first flow path member 50 and a second flow path member 60. A plurality of discharge modules 200 are bonded to the bonding surface of the first flow path member 50 with an adhesive (not shown). The flow path member 210 distributes the liquid supplied from the liquid supply unit 220 to each discharge module 200 and returns the liquid flowing out of the discharge module 200 to the liquid supply unit 220. The flow path member 210 is fixed to the liquid discharge unit support part 81 with screws, which prevents the flow path member 210 from warping or deforming.

[0028] FIG. 6 is a diagram illustrating a detailed configuration of the flow path member 210. FIG. 6(a) shows the support member 30 provided on the surface of the first flow path member 50 on which the discharge module 200 is mounted, and FIG. 6(b) shows the surface of the first flow path member 50 that abuts against the support member 30. FIG. 6(c) shows a cross-sectional view of the first flow path member 50 in a plane perpendicular to the Z direction and near the center in the Z direction, and FIG. 6(d) shows the surface of the second flow path member 60 that abuts against the liquid discharge unit support part 81. Note that FIGS. 6(a) to 6(c) are views seen from the discharge module 200 side, and FIG. 6(d) is a view seen from the liquid discharge unit support part 81 side.

[0029] A plurality of support members 30 arranged in the Y direction are disposed on the surface of the first flow path member 50 opposite to the second flow path member 60, and one element substrate 10 is disposed on each support member 30. By adjusting the number of arranged discharge modules 200, it is possible to configure liquid discharge heads 3 of various sizes.

[0030] 6(a), the support member 30 has, on its surface that abuts against the element substrate 10, communication ports 31 that are fluidly connected to the element substrate 10 and serve as the individual supply flow channels 213a and the individual recovery flow channels 213b described above in Fig. 3. As shown in Fig. 6(b), the communication ports 31 are fluidly connected to the common supply flow channel 211 or the common recovery flow channel 212 via communication ports 51 that the flow channel member 50 has.

[0031] As shown in FIG. 6(c), the middle layer located near the center of the first flow path member 50 in the Z direction is In 3 Common flow channel grooves 61 and 62, which become the common supply flow channel 211 and the common recovery flow channel 212 described above, extend in the Y direction. As shown in Fig. 6(d), a common communication port 63 that is fluidly connected to the liquid supply unit 220 is formed at both ends or one end of the common flow channel grooves 61 and 62.

[0032] 7(a) and 7(b) are a perspective view and a cross-sectional view for explaining the flow path structure formed inside the liquid discharge unit 300. Fig. 7(a) is an enlarged perspective view of the flow path member 210 as viewed from the Z direction, and Fig. 7(b) is a cross-sectional view taken along line VIIb-VIIb in Fig. 7(a).

[0033] The element substrate 10 of the ejection module 200 is placed on the communication port 51 of the first flow path member 50 via the support member 30. Note that while only the communication port 51 corresponding to the common supply flow path 211 is shown in FIG. 7(b), in another cross section, the common recovery flow path 212 and the communication port 51 are communicated with each other as shown in FIG. 6. The support member 30 and the element substrate 10 included in each ejection module 200 are formed with a flow path for supplying ink from the first flow path member 50 to the heating resistor elements 15 (see FIG. 9) provided on the element substrate 10. Furthermore, the support member 30 and the element substrate 10 are formed with a flow path for recovering (circulating) part or all of the liquid supplied to the heating resistor elements 15 to the first flow path member 50.

[0034] As described above, the common supply flow path 211 is connected to the negative pressure control unit 230H, which has a relatively high pressure, and the common recovery flow path 212 is connected to the negative pressure control unit 230L, which has a relatively low pressure. An ink supply path is formed that supplies ink to a flow path formed in the element substrate 10 through the common communication port 63 (see FIG. 6), the common supply flow path 211, and the communication port 31. Similarly, an ink recovery path is formed from the flow path in the element substrate 10, having the communication port 31, the communication port 51, the common recovery flow path 212, and the common communication port 63 (see FIG. 6(d)). While the ink is circulated in this way, an ejection operation is performed in the element substrate 10 in accordance with the ejection data, and the ink supplied by the ink supply path that is not consumed by the ejection operation is recovered by the ink recovery path.

[0035] <Configuration of the dispensing module> FIG. 8(a) is a perspective view showing one discharge module 200, and FIG. 8(b) is an exploded view thereof. The discharge module 200 is manufactured by first bonding the element substrate 10 and the flexible wiring substrate 40 to a support member 30 having a communication opening 31 formed therein. Then, the electrode pads 16 on the element substrate 10 are electrically connected to the terminals 41 on the flexible wiring substrate 40 by wire bonding, and then the wire bonding portions (electrical connection portions) are covered and sealed with a sealing material 110. For example, the flexible wiring substrate 40 may be manufactured by bonding copper foil to polyimide tape with an adhesive and patterning the copper foil to form wiring, thereby electrically connecting the electrode pads 16 on the element substrate 10. The terminals 42 on the flexible wiring substrate 40 opposite the element substrate 10 are electrically connected to the connection terminals 93 (see FIG. 5) of the electrical wiring substrate 90. The support member 30 is a support for supporting the element substrate 10 and also a flow path member that fluidly connects the element substrate 10 and the flow path member 210. Therefore, it is preferable that the support member 30 has high flatness and can be bonded to the element substrate with sufficiently high reliability. For example, alumina or a resin material is preferable. Sealing of the electrical connection portion will be described in detail later.

[0036] <Configuration of element substrate> The configuration of the element substrate 10 in this embodiment will be described. Fig. 9(a) shows a plan view of the surface of the element substrate 10 on which the ejection ports 13 are formed, Fig. 9(b) shows an enlarged view of the portion indicated by A in Fig. 9(a), and Fig. 9(c) shows a plan view of the back surface of Fig. 9(a). Fig. 10 is a cross-sectional perspective view of the element substrate 10 taken along line XX in Fig. 9(a). Hereinafter, the direction in which an ejection port array in which a plurality of ejection ports 13 are arranged extends will be referred to as the "ejection port array direction."

[0037] As shown in FIG. 9(b), a heating resistor element 15, which is a heating element (pressure-generating element) for generating bubbles in the liquid by utilizing the thermal energy generated by the liquid, is disposed at a position corresponding to each ejection port 13. Pressure chambers 23, each containing a heating resistor element 15, are defined by partition walls 22 formed by a first layer 121 (described later) of the flow path forming member 12. The heating resistor element 15 is electrically connected to the electrode pad 16 by electrical wiring (not shown) provided on the element substrate 10. The heating resistor element 15 generates heat and boils the liquid based on pulse signals input from the control circuit of the liquid ejection device 1000 via an electrical wiring board 90 (see FIG. 5) and a flexible wiring board 40 (see FIG. 8). The liquid is ejected from the ejection port 13 by the bubbling force caused by this boiling. As shown in FIG. 9(b), a liquid supply channel 18 extends on one side along each ejection port row, and a liquid recovery channel 19 extends on the other side. The liquid supply path 18 and the liquid recovery path 19 are flow paths that extend in the ejection port array direction provided on the element substrate 10, and communicate with the ejection ports 13 via the supply ports 17a and the recovery ports 17b, respectively. Figures 9(a) to 9(c) show, as an example, an element substrate 10 having 16 ejection port arrays.

[0038] As shown in FIGS. 9(c) and 10, a sheet-like cover plate 20 is laminated on the back surface of the element substrate 10 opposite the surface on which the ejection ports 13 are formed. As shown in FIG. 9(c), the cover plate 20 is provided with a plurality of openings 21 that communicate with the liquid supply channels 18 and the liquid recovery channels 19, which will be described later. In this embodiment, the cover plate 20 is provided with four supply openings 21a for each liquid supply channel 18 and three recovery openings 21b for each liquid recovery channel 19, but the number of openings is not limited to this. As shown in FIG. 9(b), each opening 21 in the cover plate 20 communicates with the communication port 51 shown in FIG. 7(a). The cover plate 20 is preferably made of a material that has sufficient corrosion resistance against liquid. Furthermore, the opening shape and position of the openings 21 must be highly accurate to ensure that ink is supplied to the pressure chambers. For this reason, it is preferable to use a photosensitive resin material or a silicon plate as the material for the cover plate 20, and form the openings 21 using photolithography. In this way, the cover plate 20 changes the pitch of the flow paths by the openings 21, and from the viewpoints of pressure loss, strength and processability, the cover plate is preferably made of a film-like material having a thickness of about 30 to 600 μm.

[0039] Next, the flow of liquid within the element substrate 10 will be described. The element substrate 10 is formed by stacking a substrate 11 made of silicon and a flow path forming member (discharge port forming member) 12 made of a photosensitive resin. In this embodiment, the flow path forming member 12 has a first layer 121 (middle layer) for forming pressure chambers 23 and a second layer 122 (upper layer) having discharge ports 13. The first layer 121 and the second layer 122 are stacked (laminated) in this order on the surface (first surface 11a) of the substrate 11, and are patterned by exposure to light with the optimal photosensitive wavelength for each layer, followed by development, to form the flow path forming member 12. Note that the flow path forming member 12 can be manufactured by any method, such as the above-described method of stacking the first and second layers, or a method of forming pressure chambers and discharge ports using a mold material or the like. A cover plate 20 is bonded to the back surface of the substrate 11. The cover plate 20 functions as a lid that forms part of the walls of the liquid supply channels 18 and liquid recovery channels 19 formed in the substrate 11 of the element substrate 10. The element substrate 10 has heating resistor elements 15 formed on one surface of the substrate 11 (see FIG. 9), and grooves that form the liquid supply channels 18 and liquid recovery channels 19 that extend along the ejection port array are formed on the back surface. The liquid supply channels 18 and liquid recovery channels 19 formed by the substrate 11 and the cover plate 20 are connected to a common supply channel 211 and a common recovery channel 212 in a flow path member 210, respectively (see FIG. 7), and a pressure difference is generated between the liquid supply channels 18 and the liquid recovery channels 19. This pressure difference causes a circulation flow C in which the liquid in the liquid supply channels 18 provided in the substrate 11 flows to the liquid recovery channels 19 via the supply ports 17a, the pressure chambers 23, and the recovery ports 17b (the flow indicated by arrows C in FIG. 10). This flow allows the ink in the ejection ports 13 and pressure chambers 23 that are not performing an ejection operation to be recovered into the liquid recovery path 19, including thickened ink, bubbles, and foreign matter that are generated by evaporation from the ejection ports 13. It also makes it possible to prevent the ink in the ejection ports 13 and pressure chambers 23 from becoming thicker or the concentration of the coloring material from increasing.As shown in Figure 7, the liquid recovered into the liquid recovery path 19 is recovered in the order of the opening 21 in the cover plate 20 and the communication port 31 in the support member 30, the communication port 31 in the support member 30, the communication port 51 in the first flow path member 50, and the common recovery flow path 212, and is then recovered into the supply path of the liquid ejection device 1000.

[0040] In other words, the liquid supplied from the liquid ejection device main body to the liquid ejection head 3 flows, and is supplied and recovered, in the following order: The liquid first flows into the liquid ejection head 3 from the liquid connection portion 111 of the liquid supply unit 220. The liquid is then supplied, in this order, to the joint rubber 100, the common communication port 63 provided in the second flow path member, and the common flow path groove 61 and communication port 51 provided in the first flow path member. The liquid is then supplied to the pressure chamber 23 via the communication port 31 provided in the support member 30, the opening 21 provided in the cover plate 20, the liquid supply path 18 and supply port 17a provided in the substrate 11, in that order. Of the liquid supplied to the pressure chamber 23, the liquid that is not ejected from the ejection port 13 flows, in that order, through the recovery port 17b and liquid recovery path 19 provided in the substrate 11, the opening 21 provided in the cover plate 20, and the communication port 31 provided in the support member 30. The liquid then flows in this order through the communication port 51 and the common flow path 62 provided in the first flow path member, the common communication port 63 provided in the second flow path member, and the joint rubber 100. The liquid then flows from the liquid connection part 111 provided in the liquid supply unit to the outside of the liquid ejection head 3. In the configuration of the circulation path shown in FIG. 3, the liquid that flows in from the liquid connection part 111 passes through the negative pressure control unit 230 and is then supplied to the joint rubber 100.

[0041] The liquid ejection head of this embodiment further includes a temperature adjustment mechanism (not shown) on the element substrate 10. The element substrate 10 is divided into multiple temperature adjustment areas, each of which is provided with a temperature sensor and an individually controllable sub-heater. The control unit 500 (see FIG. 2) uses these temperature sensors and sub-heaters to adjust the temperature based on the temperature (target temperature) set for each area. That is, the control unit 500 drives the sub-heater only in areas where the temperature detected by the temperature sensor is equal to or lower than the target temperature. Setting the target temperature of the element substrate 10 to a relatively high temperature reduces the viscosity of the ink, enabling optimal ejection and circulation. This temperature control keeps temperature variations within the element substrate 10 and among multiple element substrates 10 within a predetermined range. This reduces ejection volume variations due to temperature variations and suppresses density unevenness in printed images. The target temperature of the element substrate 10 is preferably set to a temperature equal to or higher than the equilibrium temperature of the element substrate 10 when all of the heating resistor elements 15 are driven at the highest possible driving frequency. As the temperature sensor, a diode sensor, an aluminum sensor, or the like can be used. Furthermore, a heating resistor element 15, which is a heat generating element, can also be used as a heating means for the element substrate 10. Specifically, the element substrate 10 can be heated by applying a voltage to the heating resistor element 15 that is not strong enough to cause bubbles. For example, the heating resistor element 15 can be used instead of a sub-heater as a heating means, or a sub-heater and a heating resistor element 15 can be used together.

[0042] <Liquid flow near the pressure chamber> 11(a) and 11(b) show the inside of the liquid ejection head, with FIG. 11(a) being a plan view (perspective view) showing the heating resistor elements and flow paths, and FIG. 11(b) being a cross-sectional view taken along line XIb-XIb in FIG. 11(a). A plurality of pressure chambers 23, each having an ejection port 13, and inlet flow paths 24a and outlet flow paths 24b communicating with each pressure chamber 23 are provided between the substrate 11 and the flow path forming member 12 of the element substrate 10. The pressure chambers 23 are separated by a wall 120 of the flow path forming member 12. The substrate 11 is configured to form a circulating flow C (see FIG. 10) in which liquid in the liquid supply path 18 flows through the supply port 17a, the inlet flow path 24a, the pressure chambers 23, the outlet flow path 24b, and the recovery port 17b to the liquid recovery path 19. The speed of the circulating flow C within the pressure chamber is preferably, for example, between 1.0 mm / s and 250 mm / s, a speed that has little effect on the accuracy of droplet impact even when the discharge operation is performed while the liquid is flowing. As shown in Figure 11(b), the discharge port 13 is an opening located at the end of a cylindrical discharge port portion 25 formed in the flow path forming member 12, and the discharge port portion 25 connects the discharge port 13 to the pressure chamber 23. The direction in which the liquid is discharged from the discharge port 13 (the up-down direction in Figure 11(b)) is referred to as the "discharge direction," and the direction in which the liquid flows within the pressure chamber 23 (the left-right direction in Figure 11(b)) is simply referred to as the "flow direction."

[0043] The plurality of supply ports 17a form a supply port array, and the plurality of recovery ports 17b form a recovery port array. An ejection port array in which a plurality of ejection ports 13 are arranged is formed between the supply port array and the recovery port array. In this embodiment, as described above, a pressure difference is created between the liquid supply channel 18 and the liquid recovery channel 19. This pressure difference causes ink to be introduced from the supply port 17a through the inlet flow channel 24a into the pressure chamber 23, and generates a circulating flow C in which ink flows from the outlet flow channel 24b to the recovery port 17b.

[0044] A heating resistor element 15 is provided on the bottom surface of the pressure chamber 23 facing the ejection port 13. The ejection port portion (nozzle) 25 penetrates the flow path forming member 12 at a position facing the pressure chamber 23. The outer end of the ejection port portion 25, i.e., the end opposite the heating resistor element 15, forms the ejection port 13 from which ink is ejected. The ejection port portion 25 or ejection port 13 is provided at a position facing the heating resistor element 15. In this specification, the ejection port 13 is an opening located on the outer surface of the flow path forming member 12 facing the recording medium 2, and the ejection port portion 25 is a portion that connects the ejection port 13 and the pressure chamber 23, and refers to a through hole that penetrates the flow path forming member 12.

[0045] 11, this embodiment does not have a filter such as a columnar structure that is often provided in the flow path of a liquid ejection head to prevent foreign matter such as dust from entering the pressure chamber 23. This is preferable because it reduces flow resistance within the flow path and enables improved ink refill performance, thereby enabling effects such as an increased ejection frequency. In the present invention, as described below, foreign matter can be trapped by the flow path (inlet flow path 24a) within the flow path forming member, which has a relatively low height, so a filter can be eliminated.

[0046] <Outlet shape> FIG. 12(a) is a plan view showing the shape of the ejection orifice 13 in this embodiment, and FIG. 12(b) is a plan view showing another example of the shape of the ejection orifice. As shown in FIG. 12(a), in this embodiment, two protrusions 27 are provided on both sides of a line L passing through the center F of the ejection orifice 13, with the same shape, protruding toward the center F. This has the effect of shortening the tail of the ejected droplet. Specifically, the ink meniscus formed between the protrusions 27 is more easily maintained than the meniscus in other areas. This allows the tail of the droplet extending from the ejection orifice 13 to be cut off at an earlier timing, thereby suppressing the generation of mist, which is a small droplet that accompanies the main droplet. Note that in FIGS. 1 to 11, the ejection orifice 13 is sometimes depicted without the protrusions 27. If the spacing 28 between the protrusions 27 is too wide, the tail of the ejected droplets becomes longer, making it more likely that small satellites will form. Therefore, the spacing 28 is preferably 7.0 μm or less, and more preferably 5.0 μm or less. On the other hand, if the spacing is too narrow, it may be difficult to form the protrusions or the ejected droplets may split into two. Therefore, the spacing 28 is preferably 2.0 μm or more. In other words, the spacing 28 is preferably 2.0 μm or more and 7.0 μm or less, and more preferably 2.0 μm or more and 5.0 μm or less. In this embodiment, the spacing 28 is set to 3.0 μm, as an example.

[0047] Furthermore, if the tip (near the center F) of the protrusion 27 is thick, the ejected droplet may be split by the protrusion 27 and break into two droplets. Therefore, the width 271 of the tip of the protrusion 27 is preferably 4.0 μm or less, and in this embodiment, it is set to 2.0 μm as an example. When the tip of the protrusion is rounded as in this embodiment shown in FIG. 12(a), the width 271 of the tip can be considered to be the length of a line segment obtained by dividing the line perpendicular to the straight line L at the tip of the protrusion and the two lines extending from the two long sides of the protrusion, as shown by the dotted line in the figure. Additionally, to increase the strength of the protrusion 27, it is preferable that the width 272 of the base of the protrusion 27 be wider than the tip 271, and in this embodiment, it is set to 4.0 μm as an example. 12(a), when the shape of the outlet 13 at the base is curved, as in the present embodiment, the length of the line segment connecting the two intersections of the outer periphery of a circular outlet 13 and two lines extending from the two long sides of the protrusion, as shown by the dotted line in the figure, can be considered to be the width 272 of the base. Thus, from the viewpoint of droplet formation, the protrusion 27 preferably has a shape in which the width tapers from the base to the tip, and the protrusion may have an arc shape as shown in FIG. 12(b).

[0048] Furthermore, it is desirable that the two protrusions 27 extend in a direction substantially parallel to the transport direction (X direction) of the recording medium 2. Because the protrusions 27 have a significant effect on the ejection of droplets, even slight variations in the shape of the two protrusions during manufacturing can cause droplets to fly in the direction of one of the protrusions, resulting in a misalignment of the landing positions. Generally, a misalignment of the landing positions in the ejection port arrangement direction (Y direction) is more easily visible on an image than a misalignment of the landing positions in the transport direction (X direction) of the recording medium. Therefore, by making the direction of the protrusions substantially parallel to the transport direction of the recording medium 2, it is possible to suppress misalignment in the ejection port arrangement direction, thereby achieving the effect of maintaining good printing. It is also desirable that the protrusions 27 extend along the direction of the liquid flow near the pressure chamber. In other words, it is desirable that the straight line L on which the protrusions are located forms an angle of 45 degrees or less with the flow path axis connecting the liquid supply path 18 and the liquid recovery path 19 or connecting the inlet flow path 24a and the outlet flow path 24b.

[0049] In this embodiment, two protrusions 27 extend toward the center F of the ejection port, but droplet formation is maintained favorably even if there is only one protrusion 27. In this case, however, the landing position may be significantly shifted in a direction where there is no protrusion 27, reducing the stability of the landing position, so it is more desirable for two protrusions 27 to extend toward the center F of the ejection port. Furthermore, the present invention can also be suitably used in liquid ejection heads whose ejection ports do not have protrusions 27.

[0050] Furthermore, in order to aim to achieve good image quality with stable ejection quality, it is desirable that the dot size of the droplets that land on the recording medium 2 is relatively small and highly precise. For this reason, in the liquid ejection head of this embodiment, the ejection volume is set to a relatively small value of 2.0 ng.

[0051] <Positional relationship between element substrates> FIG. 13 is a partially enlarged plan view showing adjacent portions of element substrates in two adjacent ejection modules. As shown in FIG. 9, this embodiment uses element substrates 10 with an outline shape that is approximately a parallelogram. As shown in FIG. 13, each ejection port array (14a to 14d) in which the ejection ports 13 are arranged in each element substrate 10 is arranged so as to be inclined at a certain angle with respect to the transport direction of the recording medium 2. As a result, the ejection port arrays in the adjacent portions of the element substrates 10 are arranged so that at least one ejection port 13 overlaps with the transport direction of the recording medium 2. In FIG. 13, two ejection ports on line D overlap with each other. With this arrangement, even if the position of the element substrate 10 is slightly deviated from the predetermined position, drive control of the overlapping ejection ports can make black streaks and white spots in the printed image less noticeable. That is, even when a plurality of element substrates 10 are arranged in a straight line (in-line) rather than in a staggered arrangement in order to prevent an increase in the length of the liquid ejection head 3 in the transport direction of the recording medium 2, the configuration of Fig. 13 can prevent black streaks and white spots at the joints between the element substrates 10. Note that, although the main plane of the element substrate 10 in this embodiment is a parallelogram, the present invention is not limited to this, and the configuration of the present invention can also be preferably applied when an element substrate having a rectangular, trapezoidal, or other shape is used.

[0052] <Configuration to prevent sealing material from flowing> The sealing of the electrical connection portion 70 in the ejection module 200 will be described in more detail below, while the problems of the present invention will be described. As described above, the electrical connection portion (wire bonding portion) between the element substrate and the electrical wiring board is covered with the sealant 110. If the sealant flows when applied, the wires will not be completely covered. Therefore, there is a conventional liquid ejection head configured to use an adhesive layer to enhance adhesion between the substrate 11 and the flow path forming member 12 (or the first layer 121) and to provide a structure 701 that acts as a wall to prevent the sealant 110 from flowing out of the substrate 11. FIG. 14 shows a plan view of a conventional element substrate 10. In FIG. 14, the structure 701, made of the same material as the adhesive layer 700, is provided between an electrode pad row 161, in which electrode pads 16 are arranged along one side of the substrate 11, and the side of the substrate 11, when the element substrate is viewed from above. However, since the thickness of the adhesion layer 700 is generally as thin as 1 to 2 μm, there is a possibility that the sealant 110 may overflow the structure 701 and flow out of the substrate. Therefore, in the present invention, a wall for preventing the sealant 110 from flowing out of the substrate 11 is formed by the flow path forming member 12.

[0053] 15 is a diagram showing the element substrate 10 in the first embodiment. In this embodiment, a structure 123 is formed between the electrode pad row 161 and one side of the element substrate 10, and is made of the same material as the flow path forming member 12. The structure 123 serves as a wall for preventing the sealant 110 from flowing from the application position. By forming the structure 123 serving as the flow prevention wall in the same layer as the flow path forming member 12, it is possible to prevent the sealant 110 from flowing more effectively by using a wall that is taller than the adhesion layer 700 without increasing the number of manufacturing steps.

[0054] As described above, the adhesion layer 700 is a resin layer provided to improve adhesion between the flow path forming member 12 and the substrate 10. The adhesion layer preferably contains a resin, more preferably at least one of a polyimide resin and a polyetheramide resin. When a resin adhesion layer 700 is provided, the adhesion layer 700 is applied to the substrate 10 in a liquid state. This limits the manufacturing process, as the adhesion layer must be applied before patterning the flow path forming member 12 to form the flow paths and pressure chambers. If the adhesion between the flow path forming member 12 and the substrate 10 is good, the adhesion layer 700 is not necessary, and the first layer 121 is preferably disposed in contact with the first surface 11a of the substrate 11. This has the advantage of fewer limitations on the manufacturing process and a reduced number of steps compared to when an adhesion layer is provided. To improve the adhesion of the first layer 121 to the substrate, for example, the first layer 121 can be made of a resin containing polyethylene glycol. Figure 15(b) shows a plan view of the element substrate 10 of this embodiment, which does not include the adhesion layer 700. Figure 15(c) shows a cross-sectional view of the dispensing module 200 corresponding to the position XVc-XVc in Figure 15(b), with the support member 30 omitted in Figure 15(c).

[0055] Board 1 1 The height of the structure 123 in the direction perpendicular to the direction A is preferably 3 μm or more and 25 μm or less. If the height of the structure 123 is too low, the sealant 110 will easily flow, as in the configuration of FIG. 14 in which the structure is provided with only the adhesive layer 700. If the height of the structure 123 is too high, it will be difficult to fill the sealant 110 around the electrical connection portion 70, or it will be difficult to form the electrical connection portion 70. In FIG. 15(c), the structure 123 is composed of only the first layer 121 of the flow path forming member. In this case, the structure 123 is preferably set to a height that easily achieves both preventing the sealant 110 from flowing and facilitating the formation of the electrical connection portion 70.

[0056] Furthermore, the distance L1 between the end of the side of the substrate 11 having the electrode pad row 161 and the structure 123 is preferably 2 μm or more and 200 μm or less. In particular, if the distance between the end of the substrate 11 and the structure 123 is large, the distance between the end of the substrate 11 and the electrode pad row 161 tends to become large, which may make it difficult to form the electrical connection part 70.

[0057] 15(c), in a direction parallel to the first surface 11a and perpendicular to the direction in which the electrode pad row 161 extends, the distance between the first layer 121 and the electrode pad row 161 is smaller than the distance between the second layer 122 and the electrode pad row 161. That is, in a cross section perpendicular to the electrode pad row 161, the first layer 121 and the second layer 122 form a step shape. In this case, the contact area of ​​the sealing material 110 with the first layer 121 increases, thereby improving the adhesion of the sealing material 110 to the element substrate 10. In particular, when the second layer 122 has a water-repellent layer on the surface on the ejection port 13 side, the adhesion between the second layer 122 and the sealing material 110 is poor, so a step shape between the first layer 121 and the second layer 122 is more preferable, as it increases the contact area between the sealing material 110 and the first layer 121. The distance L2 between the end of the first layer 121 on the electrode pad row 161 side and the end of the second layer 122 in a direction parallel to the first surface 11a and perpendicular to the direction in which the electrode pad row 161 extends can be, for example, 1 to 2000 μm.

[0058] In the following embodiment, differences from the first embodiment will be mainly described, and descriptions of parts similar to those in the above-described configuration will be omitted.

[0059] (Second embodiment) 16A and 16B are diagrams showing an element substrate 10 according to this embodiment, with FIG. 16A showing a configuration having an adhesive layer and FIG. 16B showing a configuration having no adhesive layer. In the first embodiment shown in FIG. 15, the sealing material may flow to the outside of the element substrate 10 in the arrangement direction of the electrode pads 16. Therefore, in this embodiment, as shown in FIG. 16A, structures 123 made of the same material as the first layer 121 are arranged on both sides in the arrangement direction of the electrode pads 16 and between the sides of the element substrate 10 and the electrode pads 16. That is, when the substrate 10 is viewed from above, the structures 123 are arranged to surround the electrode pad row.

[0060] (Third embodiment) 17(a) and (b) are diagrams showing an element substrate 10 according to this embodiment, with FIG. 17(a) showing a configuration including an adhesive layer and FIG. 17(b) showing a configuration without an adhesive layer. Also, FIG. 17(c) shows a cross-sectional view of the discharge module 200 corresponding to the position XVIIc-XVIIc in FIG. 17(b). In this embodiment, the first layer 121 is formed over substantially the entire first surface 11a of the element substrate 10, and the first layer 121 is removed only around the electrode pad row 161. In other words, when the substrate 11 is viewed from above, the electrode pad row 161 is located within the opening 124 of the first layer 121. This increases the area of ​​the substrate 11 covered by the first layer 121 compared to the first and second embodiments, thereby improving the protection of the substrate 11. In other words, the area of ​​the substrate 11 that is covered only by the sealing material 110 is reduced compared to the first and second embodiments, thereby improving the protection of the substrate 11. Here, the distance L3 between the first layer 121 and the electrode pad row 161 on the side of the region where the ejection ports are formed in the direction parallel to the first surface 11a is preferably in the range of 2 μm to 200 μm.

[0061] 17, the second layer 122 in which the discharge ports 13 are formed is disposed only in the formation region of the discharge ports 13, and the openings 124 are formed only in the first layer 121. However, a configuration may also be adopted in which the flow path forming member 12 is disposed over substantially the entire first surface 11a of the substrate 11, and the openings 124 are formed in the first layer 121 and the second layer 122.

[0062] (Fourth embodiment) 18A and 18B are diagrams showing an element substrate 10 according to this embodiment, with FIG. 18A showing a configuration with an adhesive layer and FIG. 18B showing a configuration without an adhesive layer. In this embodiment, a plurality of openings 124 are formed by removing the first layer 121 corresponding to the individual electrode pads 16. This increases the area of ​​the substrate 11 covered by the first layer 121 compared to the third embodiment shown in FIG. 17, thereby further improving the protection of the substrate 11. In this case, for example, the distance between the first layer 121 and the electrode pad row 161 in the direction parallel to the first surface 11a can be set to a range of 2 μm to 20 μm.

[0063] Furthermore, if one element substrate 10 has a plurality of openings 124, a configuration in which a plurality of electrode pads 16 are arranged in one opening 124 may be adopted. Even in this case, the same configuration as in the third embodiment may be adopted. First layer 121 This provides an advantage of improving the protection of the substrate compared to a configuration in which all electrode pads 16 are arranged in one opening.

[0064] 18, the second layer 122 in which the discharge ports 13 are formed is disposed only in the formation region of the discharge ports 13, and the plurality of openings 124 are formed only in the first layer 121. However, a configuration may also be adopted in which the flow path forming member 12 is disposed over substantially the entire first surface 11a of the substrate 11, and the openings 124 are formed in the first layer 121 and the second layer 122. [Explanation of symbols]

[0065] 3 Liquid ejection head 10 Element substrate 11 Circuit Board 12 Flow path forming member 16 electrode pads 110 Encapsulating material 200 Dispensing Module 40 Electrical wiring board 70 Electrical Connections

Claims

1. on a first surface of the substrate, an element substrate including: an element for ejecting liquid; a flow path forming member having a pressure chamber and an ejection port communicating with the pressure chamber and ejecting the liquid; and a pad row in which a plurality of pads electrically connected to the element are arranged along one side of the substrate; an electric wiring board connected to the pads via electrical connection portions; a sealing material disposed on the first surface of the substrate so as to cover the electrical connection portion; In a plan view of the element substrate, the flow path forming member has an opening, and the pad is positioned within the opening.

2. The flow path forming member is a first layer in contact with the first surface and forming the pressure chamber; a second layer provided on the opposite side of the first layer from the substrate and having the discharge port; and The liquid ejection head according to claim 1 , wherein the opening is provided in the first layer.

3. 3. The liquid ejection head according to claim 2, wherein the height of the first layer in a direction perpendicular to the substrate is 3 [mu]m or more and 25 [mu]m or less.

4. 3. The liquid ejection head according to claim 1, wherein the pad row is located inside the opening.

5. on a first surface of the substrate, an element substrate including: an element for ejecting liquid; a flow path forming member having a pressure chamber and an ejection port communicating with the pressure chamber and ejecting the liquid; and a pad row in which a plurality of pads electrically connected to the element are arranged along one side of the substrate; an electric wiring board connected to the pads via electrical connection portions; a sealing material disposed on the first surface of the substrate so as to cover the electrical connection portion; a structure made of the same material as the flow path forming member is provided between the one side and the pad row when viewed from a direction perpendicular to the substrate, A liquid ejection head, wherein the height of the structure in a direction perpendicular to the substrate is 3 μm or more and 25 μm or less.

6. The flow path forming member is a first layer in contact with the first surface and forming the pressure chamber; a second layer provided on the opposite side of the first layer from the substrate and having the discharge port; and The liquid ejection head according to claim 5 , wherein the structure is made of the same material as the first layer.

7. The liquid ejection head according to claim 5 , wherein the structure is disposed so as to surround the pad when the element substrate is viewed from above.

8. The liquid ejection head according to claim 5 , wherein the structure is disposed so as to surround the pad row when the element substrate is viewed from above.

9. In a direction parallel to the first surface and perpendicular to the direction in which the pad row extends, On the side where the discharge port is formed, 7. The liquid ejection head according to claim 2, wherein the distance between the first layer and the pad row is smaller than the distance between the second layer and the pad row.

10. 7. A liquid ejection head according to claim 2, wherein the distance between the first layer and the pad row in a direction parallel to the first surface and perpendicular to the direction in which the pad row extends is 2 μm or more and 200 μm or less.

11. The liquid ejection head according to claim 1 or 5, wherein the electrical connection portion is a wire.

12. The liquid ejection head according to claim 1 or 5, wherein the flow path forming member is made of resin.

13. 7. The liquid ejection head according to claim 2, wherein the first layer is disposed on the substrate in contact with the first surface.

14. 7. The liquid ejection head according to claim 2, wherein the first layer is disposed on the first surface of the substrate via an adhesive layer.

15. The liquid ejection head according to claim 2 or 6, wherein the first layer contains polyethylene glycol.

16. on a first surface of the substrate, an element substrate including: an element for ejecting liquid; a flow path forming member having a pressure chamber and an ejection port communicating with the pressure chamber and ejecting the liquid; and a pad row in which a plurality of pads electrically connected to the element are arranged along one side of the substrate; an electric wiring board connected to the pads via electrical connection portions; a sealing material disposed on the first surface of the substrate so as to cover the electrical connection portion; A method for manufacturing a liquid ejection head, wherein, in a plan view of the element substrate, the flow path forming member has an opening, and the pad is positioned within the opening, forming a layer to be the flow path forming member on the first surface of the substrate; and forming the flow path forming member by patterning the layer to simultaneously form the pressure chambers and the openings.

17. The flow path forming member is a first layer in contact with the first surface and forming the pressure chamber; a second layer provided on the opposite side of the first layer from the substrate and having the discharge port; and A method for manufacturing a liquid ejection head, wherein the opening is provided in the first layer, 17. A method for manufacturing a liquid ejection head according to claim 16, comprising: a step of forming a layer that will become the first layer on the first surface of the substrate; and a step of patterning the layer that will become the first layer to simultaneously form the pressure chamber and the opening.

Images