Liquid discharge head

Abstract

To reduce fixing of a liquid and malfunction of a valve body in an inflow port of the liquid, and maintain image quality of a recorded matter to which the liquid is discharged.SOLUTION: A liquid discharge head has a liquid discharge port, a supply passage for supplying a liquid to the discharge port, and a pressure control unit for controlling a pressure of the liquid. The pressure control unit has a fluid chamber having an inflow port of the liquid, and an outflow port for flowing out the liquid to the supply passage, a valve body which can take a close position to close the inflow port and an open position to open the inflow port, a movable member which can take a first position to make the valve body positioned at the close position and a second position to make the valve body positioned at the open position, and an energization member for making the movable member positioned at the first position, in the fluid chamber. When the pressure in the fluid chamber becomes larger than the energization force, the movable member is moved to the second position from the first position, and a direction in which the liquid flows in the inflow port is a direction crossing a gravity direction.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The technology disclosed herein relates to a liquid ejection head that performs recording by an inkjet method. [Background technology]

[0002] In a liquid ejection device, the ejection port of a recording element substrate (hereinafter, sometimes simply referred to as a "chip") mounted on a liquid ejection head is open to the atmosphere, and the ink used for printing forms a meniscus at the ejection port by capillary action. Here, the pressure applied to the ink at the ejection port is generally negative. As a source of this negative pressure, there is a method of using the head difference between the liquid level of an ink storage tank communicating with the ejection port and the liquid level at the ejection port, but the head difference changes according to the change in the position of the liquid level of the ink storage tank, and the negative pressure applied to the ejection port also fluctuates. As a result, the meniscus surface position inside the ejection port fluctuates, and the volume of the ejected droplet also fluctuates. If this fluctuation becomes large, for example, by 3% or more, it may affect image quality due to uneven density of the ejected ink.

[0003] Therefore, in order to stabilize the meniscus surface position inside the ejection port, a technology has been proposed in which a valve lever is used in the pressure control mechanism, as disclosed in Patent Document 1, to control the negative pressure applied to the ink at the ejection port using a pressure control unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-162084 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to achieve high-quality printing, inks containing a large amount of solids such as pigments are used, and white inks in particular contain pigments such as titanium dioxide, which are prone to settling and adhesion. However, in the technology of Patent Document 1, the axis of the valve and the sealing surface of the valve are arranged vertically (horizontally) relative to the direction of gravity. In this case, when the above-mentioned ink is used, the ink may adhere to the inlet, causing malfunction of the valve lever to open and close, or the adhered ink may change the flow resistance of the ink flowing in from the inlet, affecting the fluctuation of the negative pressure in the negative pressure chamber. As a result, the image quality of the recorded matter may deteriorate due to unevenness in the ink concentration.

[0006] In view of the above-mentioned problems, the technology disclosed herein aims to provide a liquid ejection head that can reduce adhesion of liquid at the liquid inlet of the pressure control unit and malfunction of the valve body, thereby maintaining the image quality of the recorded material onto which the liquid is ejected. [Means for solving the problem]

[0007] In order to achieve the above object, a liquid ejection head according to the present disclosure has an ejection port for ejecting liquid, a supply path for supplying liquid to the ejection port, and a pressure control unit for controlling the pressure of the liquid supplied to the supply path from a liquid supply source, the pressure control unit including: a fluid chamber having an inlet through which the liquid from the liquid supply source flows in, and an outlet through which the liquid flowing in from the inlet flows out to the supply path; a valve body configured to be able to take a closed position that closes the inlet and an open position that opens the inlet; a movable member configured within the fluid chamber to be able to take a first position acting on the valve body to position the valve body at the closed position, and a second position acting on the valve body to position the valve body at the open position; and a biasing section that applies a biasing force to the movable member to position the movable member at the first position. and a movable member configured to move from the first position to the second position when the pressure in the fluid chamber becomes greater than the biasing force of the biasing member, the liquid ejection head being characterized in that, when the liquid ejection head is attached to a liquid ejection device that ejects the liquid onto a recorded object using the liquid ejection head, the direction in which the liquid flows into the inlet is a direction that intersects the direction of gravity. Effect of the Invention

[0008] According to the technique of the present disclosure, it is possible to reduce adhesion of liquid at the liquid inlet of the pressure control unit and malfunction of the valve body, thereby maintaining the image quality of the recorded material onto which the liquid is ejected. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view illustrating a liquid ejection device according to an embodiment. [Diagram 2] 1 is a schematic diagram illustrating a liquid flow path of a liquid ejection device according to an embodiment. [Diagram 3] 1 is a schematic perspective view showing a liquid ejection head according to an embodiment. [Figure 4] FIG. 1 is an exploded perspective view showing a liquid ejection head according to an embodiment. [Diagram 5] 3 is a schematic diagram showing a flow path formed in a flow path member according to one embodiment. FIG. [Figure 6] FIG. 1 is a schematic perspective view illustrating a liquid ejection unit according to an embodiment. [Figure 7] FIG. 2 is a schematic perspective view showing a configuration of a discharge module according to an embodiment. [Figure 8] FIG. 2 is a bird's-eye view showing a configuration of a recording element substrate according to an embodiment. [Figure 9] FIG. 2 is a cross-sectional perspective view of a recording element substrate according to an embodiment. [Figure 10] FIG. 2 is a schematic diagram illustrating a negative pressure control unit according to an embodiment. [Figure 11] FIG. 2 is a schematic diagram showing a cross section of a negative pressure control unit according to an embodiment. [Figure 12] FIG. 2 is a schematic diagram showing a cross section of a negative pressure control unit according to an embodiment. [Figure 13] 4 is a graph showing the relationship between valve resistance and valve opening in one embodiment. [Figure 14] FIG. 13 is a schematic diagram showing a cross section of a negative pressure control unit according to a modified example. [Figure 15] FIG. 13 is a schematic diagram showing a negative pressure control unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Preferred embodiments of the technology of the present disclosure will be described in detail below with reference to the accompanying drawings. In each drawing, the same reference numerals are used for the same components, and duplicated descriptions will be omitted. Each embodiment will be described in more detail below. The numerical values ​​shown in each of the following examples are merely examples, and the technology of the present disclosure is not limited to these. The technology of the present disclosure is not limited to each embodiment, and includes combinations of these embodiments and applications to other technical fields.

[0011] (First embodiment) A liquid ejection device according to a first embodiment of the technology of the present disclosure will be described below. The liquid ejection device according to this embodiment is an inkjet recording device (recording device) that circulates liquid such as ink between a tank and a liquid ejection head. However, in this embodiment, the ink may be supplied to the liquid ejection head in other forms. For example, the following embodiment can also be applied to a recording device in which the ink is not circulated but is instead made to flow by providing tanks on the upstream and downstream sides of the liquid ejection head and causing the ink to flow from one tank to the other tank.

[0012] Also, it is assumed that the liquid ejection device of this embodiment is a so-called line-type head liquid ejection device having a liquid ejection head whose length corresponds to the width of the recording medium onto which the ink is ejected. However, the liquid ejection device of this embodiment may also be a liquid ejection device having a so-called serial-type liquid ejection head that ejects ink while scanning the recording medium. An example of a serial-type liquid ejection head is a configuration in which one recording element substrate for black ink and one recording element substrate for color inks are mounted, for example. However, this is not limited to this, and multiple Alternatively, a configuration may be adopted in which a short line head having a length shorter than the width of the recording medium is scanned across the recording medium, in which the recording element substrate is arranged so that the ejection openings overlap along the ejection opening row direction.

[0013] <Description of Inkjet Recording Apparatus> 1 shows a schematic diagram of a liquid ejection device, particularly an inkjet recording device 1000 (hereinafter also referred to as a recording device) that performs recording by ejecting ink, according to this embodiment. The recording device 1000 has a transport section 1 that transports a recording medium 2, and line-type liquid ejection heads 3B, 3C, 3M, and 3Y (hereinafter also referred to as liquid ejection heads 3) that are arranged substantially perpendicular to the transport direction of the recording medium 2. The liquid ejection heads 3B, 3C, 3M, and 3Y eject black ink, cyan ink, magenta ink, and yellow ink, respectively. This allows the recording device 1000 to perform full-color printing using so-called CMYK inks.

[0014] The recording device 1000 is a line-type recording device that performs continuous recording in one pass while transporting a plurality of recording media 2 continuously or intermittently. The recording media 2 are not limited to cut paper, but may be continuous rolled paper. The recording media 2 are also not limited to paper, but may be film or the like. As will be described later, a supply path that supplies ink to the liquid ejection head 3, a main tank, and a buffer tank (see FIG. 2) are fluidly connected. An electrical control unit that transmits power and ejection control signals to the liquid ejection head 3 is also electrically connected to the liquid ejection head 3. The liquid flow paths and electrical signal paths within the liquid ejection head 3 will be described later.

[0015] <Ink circulation system> FIG. 2 is a schematic diagram showing a circulation flow path applied to the recording apparatus of this embodiment. As shown in FIG. 2, the liquid ejection head 3 is fluidly connected to a first circulation pump 1002, a buffer tank 1003, and the like. In FIG. 2, only a flow path through which one color of ink flows among CMYK inks is shown for the sake of simplicity of explanation, but in reality, circulation flow paths for four colors are provided in the liquid ejection head 3 and the recording apparatus 1000. The buffer tank 1003 as a sub-tank connected to the main tank 1006 as a liquid supply source has an air communication port (not shown) that communicates the inside of the tank with the outside, and can discharge air bubbles in the ink to the outside. The main tank 1006 stores ink to be supplied to the liquid ejection head 3 described below. The buffer tank 1003 is also connected to a refill pump 1005. In the liquid ejection head 3, ink is consumed by discharging (discharging) ink from the ejection port of the liquid ejection head, such as for recording by ejecting ink and suction recovery. At this time, the refill pump 1005 transfers an amount of ink corresponding to the consumption amount from the main tank 1006 to the buffer tank 1003 .

[0016] The first circulation pump 1002 draws ink from the liquid connection part 111 of the liquid ejection head 3 and flows it into the buffer tank 1003. When the liquid ejection head 3 is driven, the first circulation pump 1002 causes a certain amount of ink to flow through the common recovery flow path 212. The negative pressure control unit 230 is provided between the flow path of the second circulation pump 1004 and the liquid ejection unit 300. The negative pressure control unit 230 operates to maintain the pressure downstream of the negative pressure control unit 230 (the liquid ejection unit 300 side) at a preset constant pressure even when the flow rate of the circulation system varies due to a difference in the duty for recording.

[0017] 2, the negative pressure control unit 230 has two pressure adjustment mechanisms, each of which is set to a different control pressure. The negative pressure control unit 230 has two negative pressure adjustment mechanisms, one on the relatively high pressure side (the side indicated by "H" in FIG. 2) and the other on the relatively low pressure side (the side indicated by "L" in FIG. 2). These two negative pressure adjustment mechanisms are connected to the common supply flow path 211 and the common recovery flow path 212 of the liquid ejection unit 300 via the liquid supply unit 220, respectively.

[0018] The liquid ejection unit 300 is provided with a common supply flow path 211, a common recovery flow path 212, and individual supply flow paths 213a and individual recovery flow paths 213b (hereinafter also referred to as individual flow paths 213) that communicate with each recording element substrate. The individual flow paths 213 communicate with the common supply flow path 211 and the common recovery flow path 212. In addition, a negative pressure adjustment mechanism H is connected to the common supply flow path 211, and a negative pressure adjustment mechanism L is connected to the common recovery flow path 212, so that a pressure difference occurs between the two common flow paths. As a result, ink flows from the common supply flow path 211 through the internal flow path of the recording element substrate 10 to the common recovery flow path 212 (the flow indicated by the arrow in FIG. 2).

[0019] In this way, in the liquid ejection unit 300, a flow occurs in which ink flows through the common supply flow path 211 and the common recovery flow path 212, while a part of the ink passes through each recording element substrate 10. Therefore, heat generated in each recording element substrate 10 can be discharged to the outside of the recording element substrate 10 by the flow through the common supply flow path 211 and the common recovery flow path 212. In addition, with this configuration, when recording is performed by the liquid ejection head 3, ink flow can be generated even in ejection ports and fluid chambers that are not performing recording, so that thickening of the ink in those areas can be suppressed. Also, thickened ink and foreign matter in the ink can be discharged to the common recovery flow path 212. Therefore, the liquid ejection head 3 of the recording device 1000 of this embodiment enables high-speed, high-quality recording on a recording medium.

[0020] The two negative pressure adjustment mechanisms arranged in the negative pressure control unit 230 do not necessarily need to be controlled to negative pressure, but only need to control the pressure so that negative pressure is maintained at the ejection port. In order to control the pressure value at the ejection port, it is necessary to suppress pressure fluctuations in the flow path from the negative pressure adjustment mechanisms to the ejection port, so it is preferable to arrange the negative pressure adjustment mechanisms in a position close to the ejection port. Therefore, it is more preferable to mount the negative pressure control unit 230 on the liquid ejection head 3.

[0021] 2, a unit combining the liquid supply unit 220 and the negative pressure control unit 230 is referred to as a pressure control assembly 2000. In order to achieve high-quality printing on a recording medium, the pressure difference is maintained by suppressing fluctuations in pressure loss that occur in the flow path from the two negative pressure adjustment mechanisms to the ejection port, and the circulating flow rate through the ejection port is stabilized. For this reason, it is preferable to mount the negative pressure control unit 230 on the liquid ejection head 3 and shorten the length of the flow path from the negative pressure adjustment mechanism of the negative pressure control unit 230 to the ejection port, thereby reducing pressure loss.

[0022] <Description of Liquid Ejection Head Configuration> The configuration of the liquid ejection head 3 according to this embodiment will be described. Figures 3A and 3B 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 3 in which, for example, 17 recording element substrates 10 are arranged in a straight line (arranged inline).

[0023] 3A and 3B, the liquid ejection head 3 includes each recording element substrate 10, a signal input terminal 91, and a power supply terminal 92 electrically connected via a flexible wiring substrate 40 and an electric wiring substrate 90. The signal input terminal 91 and the power supply terminal 92 are electrically connected to a control unit of the recording device 1000, and supply an ejection drive signal and power required for ejecting ink to the recording element substrate 10, respectively. By consolidating the wiring using an electric circuit in the electric wiring substrate 90, the number of signal input terminals 91 and power supply terminals 92 can be reduced compared to the number of recording element substrates 10. This can reduce the number of electrical connections that need to be removed when assembling the liquid ejection head 3 to the recording device 1000 or when replacing the liquid ejection head 3.

[0024] 3B, liquid connection parts 111 provided on both ends of the liquid ejection head 3 are connected to a liquid supply system of the recording apparatus 1000. As a result, ink of four colors, CMYK, is supplied from the supply system of the recording apparatus 1000 to the liquid ejection head 3, and the ink that has passed through the liquid ejection head 3 is collected in the supply system of the recording apparatus 1000. In this way, the ink of each color can be circulated through the flow paths of the recording apparatus 1000 and the flow paths of the liquid ejection head 3.

[0025] 4 shows an exploded perspective view of each part or unit that constitutes the liquid ejection head 3. The liquid ejection unit 300, the liquid supply unit 220, and the electric wiring board 90 are attached to a housing 80. The liquid supply unit 220 is provided with a liquid connection part 111, and the liquid supply unit 220 is provided with filters 221 for each color that communicate with each opening of the liquid connection part 111 in order to remove foreign matter in the ink being supplied. Each of the two liquid supply units 220 has filters 221 for two colors.

[0026] The ink that has passed through the filter 221 is supplied to the negative pressure control unit 230 arranged on the liquid supply unit 220 corresponding to each color. The negative pressure control unit 230 is a unit consisting of a pressure adjustment valve for each color. The pressure loss change in the supply system of the recording device 1000 (the supply system on the upstream side of the liquid ejection head 3) caused by the fluctuation in the flow rate of the ink is attenuated by the action of a valve, a spring member, and the like provided in each pressure adjustment valve. The negative pressure control unit 230 stabilizes the negative pressure change downstream of the negative pressure control unit 230 (the liquid ejection unit 300 side) within a certain range. As shown in FIG. 2, two pressure adjustment valves are built into the negative pressure control unit 230 for each color. The two pressure adjustment valves are set to different control pressures, and the high pressure side communicates with the common supply flow path 211 in the liquid ejection unit 300 and the low pressure side communicates with the common recovery flow path 212 via the liquid supply unit 220.

[0027] The housing 80 is composed of a liquid discharge unit support part 81 and an electric wiring board support part 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 part 82 supports the electric wiring board 90 and is fixed to the liquid discharge unit support part 81 by screwing. The liquid discharge unit support part 81 corrects the warping and deformation of the liquid discharge unit 300, ensures the relative position accuracy of the multiple recording element boards 10, and thereby suppresses streaks and unevenness in the recorded matter. For this reason, the liquid discharge unit support part 81 preferably has sufficient rigidity, and is preferably made of a metal material such as SUS or aluminum, or a ceramic such as alumina. The liquid discharge unit support part 81 is provided with openings 83 and 84 into which the joint rubber 100 is inserted. The ink supplied from the liquid supply unit 220 is led to the second flow path member 60 constituting the liquid discharge unit 300 via the joint rubber 100.

[0028] The liquid ejection unit 300 is composed of a plurality of ejection modules 200 and a flow path member 210, and a cover member 130 is attached to the surface of the liquid ejection unit 300 facing the recording medium. Here, as shown in FIG. 4, the cover member 130 is a member having a frame-shaped surface with a long opening 131, and the recording element substrate 10 and the sealant 110 (FIG. 7A) included in the ejection module 200 are exposed from the opening 131. The frame portion around the opening 131 functions as a contact surface of a cap member that caps the liquid ejection head 3 during standby for recording. For this reason, it is preferable to apply an adhesive, sealant, filler, or the like along the periphery of the opening 131 to fill in unevenness and gaps on the ejection port surface of the liquid ejection unit 300, so that a closed space is formed when capped.

[0029] Next, the configuration of the flow path member 210 included in the liquid discharge unit 300 will be described. As shown in FIG. 4, the flow path member 210 is formed by laminating a first flow path member 50 and a second flow path member 60, and a plurality of discharge modules 200 are bonded to a bonding surface 53 of the first flow path member 50 by an adhesive (not shown). The flow path member 210 is formed by bonding the liquid supplied from the liquid supply unit 220 to the bonding surface 53 of the first flow path member 50 by an adhesive (not shown). This is a flow path configuration that distributes liquid to each discharge module 200 and returns the liquid returning from the discharge modules 200 to the liquid supply unit 220. The flow path member 210 is fixed to the liquid discharge unit support part 81 by screwing.

[0030] 5A to 5C are diagrams for explaining a detailed configuration of the flow path member 210. Fig. 5A and Fig. 5B show the front and back surfaces of the first flow path member 50, and Fig. 5C shows the front surface of the second flow path member 60. Fig. 5A is the surface that comes into contact with the recording element substrate 10, and Fig. 5C is the surface that comes into contact with the liquid supply unit 220. The surface of the first flow path member 50 shown in Fig. 5B and the back surface of the second flow path member 60 shown in Fig. 5C come into contact with each other.

[0031] The first flow path member 50 has communication ports 51 arranged in a repeating pattern in the Y direction, and each repeating pattern corresponds to one recording element substrate 10. As shown in Fig. 5A, the surface of the first flow path member 50 that abuts against the recording element substrate 10 has communication ports 51 formed thereon that are fluidly connected to the recording element substrate 10 and serve as the individual supply flow paths 213a and the individual recovery flow paths 213b described in Fig. 2A and Fig. 2B.

[0032] 5C, a common flow channel groove 62 is formed extending in the Y direction to serve as the common supply flow channel 211 and the common recovery flow channel 212 described in Figures 2A and 2B. Common communication ports 61 that are fluidly connected to the liquid supply unit 220 are formed at both ends of the common flow channel groove 62.

[0033] 6A and 6B are a perspective view and a cross-sectional view for explaining a flow path structure formed inside the flow path member 210. Fig. 6B is a cross-sectional view taken along line AA in Fig. 6A. A common supply flow path 211 and a common recovery flow path 212 extending in the longitudinal direction (Y direction) of the first flow path member 50 are fluidly connected to the opening 21 of the recording element substrate 10 via the communication port 51 of the first flow path member 50 and the liquid supply port 31 of the support member 30.

[0034] As already described, the common supply flow path 211 is connected to the first negative pressure control unit 230a with a relatively high pressure, and the common recovery flow path 212 is connected to the second negative pressure control unit 230b with a relatively low pressure. Therefore, an ink supply flow path to the recording element substrate 10 is formed, which is composed of the common communication port 61 (see FIG. 6), the common supply flow path 211, the communication port 51 (individual supply flow path 213a), and the recording element substrate 10. Similarly, an ink recovery flow path is formed, which is composed of the recording element substrate 10, the communication port 51 (individual recovery flow path 213b), the common recovery flow path 212, and the common communication port 61 (see FIG. 6). While the ink is circulated in this way, the recording element substrate 10 performs an ejection operation according to the ejection data, and the ink that is supplied in the ink supply flow path and is not consumed by the ejection operation is recovered in the ink recovery flow path.

[0035] <Explanation of the discharge module> FIG. 7A is a perspective view showing one discharge module 200, and FIG. 7B is an exploded view thereof. In the manufacturing method of the discharge module 200, first, the recording element substrate 10 and the flexible wiring substrate 40 are bonded onto the support member 30 on which the liquid supply port 31 is provided in advance. Then, the terminal 16 on the recording element substrate 10 and the terminal 41 on the flexible wiring substrate 40 are electrically connected by wire bonding, and then the wire bonding portion (electrical connection portion) is covered and sealed with a sealant 110. The terminal 42 on the flexible wiring substrate 40 opposite the recording element substrate 10 is electrically connected to the connection terminal 93 (see FIG. 4) of the electrical wiring substrate 90. The support member 30 is a support for supporting the recording element substrate 10 and is also a flow path member for fluidly communicating the recording element substrate 10 and the flow path member 210, so it is preferable that the support member 30 has a high flatness and can be joined to the recording element substrate with sufficiently high reliability. For example, alumina or a resin material is preferable as the material of the support member 30.

[0036] <Explanation of the structure of the recording element substrate> Fig. 8A shows a plan view of the surface of the recording element substrate 10 on which the ejection ports 13 are formed, Fig. 8B shows an enlarged view of the circled portion shown in B of Fig. 8A, and Fig. 8C shows a plan view of the back surface of Fig. 8A. Here, the configuration of the recording element substrate 10 in this embodiment will be described.

[0037] 8A shows a case where four ejection port arrays are formed in the ejection port forming member 12 of the recording element substrate 10, but the number of ejection port arrays is not limited to this. Note that hereinafter, the direction in which the ejection port array in which the multiple ejection ports 13 are arranged extends is referred to as the "ejection port array direction."

[0038] As shown in FIG. 8B, a recording element 15, which is a heat generating element (pressure generating element) for foaming ink by using thermal energy, is disposed at a position corresponding to each ejection port 13. A fluid chamber 23 in which the recording element 15 is disposed is partitioned by a partition wall 22. The recording element 15 is electrically connected to a terminal 16 by an electric wiring (not shown) provided on the recording element substrate 10. The recording element 15 generates heat based on a pulse signal input from a control circuit of the recording device 1000 via an electric wiring substrate 90 and a flexible wiring substrate 40 to boil the ink. The ink is ejected from the ejection port 13 by the force of foaming caused by this boiling. As shown in FIG. 8B, a liquid supply path 18 extends on one side along each ejection port row, and a liquid recovery path 19 extends on the other side. The liquid supply path 18 and the liquid recovery path 19 are flow paths extending in the ejection port row direction provided on the recording element substrate 10, and communicate with the ejection port 13 via a supply port 17a and a recovery port 17b, respectively.

[0039] 8C, a sheet-like cover plate 20 is laminated on the rear surface of the recording element substrate 10 opposite to the surface on which the ejection ports 13 are formed, and the cover plate 20 is provided with a plurality of openings 21 (opening rows) that communicate with liquid supply paths 18 and liquid recovery paths 19, which will be described later. In this embodiment, three openings 21 are provided in the cover plate 20 for one liquid supply path 18, and two openings 21 are provided in the cover plate 20 for one liquid recovery path 19. It should be noted that the number of openings 21 is not limited to this.

[0040] As shown in Fig. 8B, each of the openings 21 of the cover plate 20 communicates with a plurality of communication ports 51 shown in Fig. 6A. It is preferable that the cover plate 20 has sufficient corrosion resistance against ink, and from the viewpoint of preventing ink color mixing, it is required that the opening shape and opening position of the openings 21 are arranged with high accuracy. For this reason, it is preferable to use a photosensitive resin material or a silicon plate as the material of the cover plate 20 and provide the openings 21 by a photolithography process.

[0041] 9 is a perspective view showing a cross section of the recording element substrate 10 and the cover plate (lid member) 20 taken along the line CC in FIG. 8A. Here, the flow of ink in the recording element substrate 10 will be described. The cover plate 20 functions as a lid forming part of the walls of the liquid supply path 18 and the liquid recovery path 19 formed in the substrate 11 of the recording element substrate 10. The recording element substrate 10 is formed by laminating the substrate 11 made of Si and the ejection port forming member 12 made of a photosensitive resin, and the cover plate 20 is bonded to the rear surface of the substrate 11. The recording elements 15 are formed on one surface of the substrate 11 (see FIG. 8B), and grooves forming the liquid supply path 18 and the liquid recovery path 19 extending along the nozzle row 13a in which the multiple ejection ports 13 are arranged are formed on the rear surface of the substrate 11.

[0042] The liquid supply path 18 and the liquid recovery path 19 formed by the substrate 11 and the cover plate 20 are respectively connected to a common supply flow path 211 and a common recovery flow path 212 in the flow path member 210, and a pressure difference is generated between the liquid supply path 18 and the liquid recovery path 19. When ink is discharged from the discharge ports 13 to perform recording, the ink in the liquid supply path 18 provided in the substrate 11 is pulled to the supply port 17a, the flow path 212, and the common supply flow path 211 in the discharge port 17a. The ink flows through the fluid chamber 23 and the recovery port 17b to the liquid recovery path 19 (arrow D). This flow allows the thickened ink, bubbles, foreign matter, etc., generated by evaporation from the ejection port 13 in the ejection port 13 and the fluid chamber 23 that are not ejecting to be recovered to the liquid recovery path 19. In addition, it is possible to suppress the ink in the ejection port 13 and the fluid chamber 23 from becoming thicker or the concentration of the coloring material from increasing. The ink recovered to the liquid recovery path 19 flows through the opening 21 of the cover plate 20 and the liquid supply port 31 of the support member 30 as shown in FIG. 7B. After that, the ink flows through the liquid supply port 31 of the support member 30, the communication port 51 of the first flow path member 50, and the common recovery flow path 212 in this order, and is recovered to the supply flow path (FIG. 2) of the recording device 1000.

[0043] <Detailed explanation of the negative pressure control unit> Next, the problem to be solved by the technology of the present disclosure will be described in detail. Figures 10A and 10B are diagrams showing the structure of a negative pressure control unit 230a (pressure reducing valve) on the high pressure side (H side) of the negative pressure control unit 230, which is an ink pressure control unit used in this embodiment. The operating principle of this negative pressure control unit 230a is similar to that of what is generally called a "pressure reducing regulator." Note that the configuration and operation of the negative pressure control unit 230b on the low pressure side (L side) are similar to those of the negative pressure control unit 230a, so detailed explanations will be omitted below.

[0044] 10A is a diagram showing the appearance of the negative pressure control unit 230a, and FIG. 10B shows a housing 231 of the negative pressure control unit 230a for accommodating each component of the negative pressure control unit 230a described below. As shown in FIG. 10A, the negative pressure control unit 230a has a pressure receiving plate 2321 and a fluid chamber 2323. As described below, the pressure receiving plate 2321 is a movable member that is displaced in response to pressure fluctuations that occur with changes in the amount of ink in the fluid chamber 2323. The operation of the pressure receiving plate 2321 operates a lever 2327, which will be described later, to control the flow of ink flowing into the fluid chamber 2323, which is a fluid chamber through which the ink flows, and the pressure of the ink in the fluid chamber 2323 and the liquid supply channel 18.

[0045] 10B, the housing 231 of the negative pressure control unit 230a has a bearing portion 2329 into which a rotating shaft 2328 described below fits, and an orifice 2320 which is an ink inlet. The orifice 2320 is composed of a circular opening provided on the upstream side (liquid flow chamber 2324 side) where the ink flows into the fluid chamber 2323, a circular opening provided on the downstream side (fluid chamber 2323 side), and a cylindrical hole connecting these openings.

[0046] 11 and 12 show a cross section of the negative pressure control unit 230a taken along the line EE in FIG. 10A. As shown in FIG. 11 and FIG. 12, the negative pressure control unit 230a has a pressure receiving plate 2321 functioning as a pressure receiving portion, a flexible film 2322 fluidically sealing the pressure receiving plate 2321 and the housing 231, and a fluid chamber 2323. In addition, on the upstream side (left side of the drawing) of the ink flowing through the fluid chamber 2323, a movable valve 2325 which is a valve body interlocked with the pressure receiving plate 2321, and an orifice 2320 which fits into the movable valve 2325 are provided. The orifice 2320 is an inlet through which ink from the main tank 1006 which is a liquid supply source flows into the fluid chamber 2323. In addition, the ink which flows into the fluid chamber 2323 from the orifice 2320 flows out from an outlet 2331 to the common supply flow channel 211 (see FIG. 2).

[0047] The movable valve 2325 has a cylindrical shaft body 2325b and a protrusion 2325c, which is a circular protrusion that protrudes towards the orifice 2320 from the surface of the shaft body 2325b that faces the orifice 2320. The movable valve 2325 is provided integrally with a lever 2327 that is disposed in the fluid chamber 2323. The movable valve 2325 is configured to be able to take a closed position that closes the orifice 2320 and an open position that opens the orifice 2320. The protrusion 2325c of the movable valve 2325 is formed such that the inner diameter of the protrusion 2325c is larger than the opening diameter of the orifice 2320. When the movable valve 2325 closes the orifice 2320, When in the closed position, the protrusion 2325c of the movable valve 2325 abuts against the housing 231 so as to surround the orifice 2320, thereby closing the orifice 2320. Note that the shape of the protrusion 2325c of the movable valve 2325 is not limited to a circular ring shape, and may be, for example, a rectangular protrusion that abuts against the wall surface 2350 so as to surround the orifice 2320 and close the ink flow path.

[0048] The lever 2327 has one end connected to the movable valve 2325 and the other end capable of abutting against the pressure plate 2321, and has a rotation shaft 2328 between these ends that abuts against the fluid chamber 2323. The lever 2327 is capable of rotating about a predetermined rotation axis of the rotation shaft 2328, with the rotation shaft 2328 as a fulcrum. Here, as an example, the rotation axis 2328a is an axis extending in a direction parallel to the paper surface of Figs. 11 and 12, and is perpendicular to both the first direction D1 and the second direction D2.

[0049] Fig. 11 shows a state in which the movable valve 2325 closes the orifice 2320, ink does not flow from the liquid circulation chamber 2324 into the housing 231 via the orifice 2320, and pressure adjustment of the ink pressure in the fluid chamber 2323 and the common supply channel 211 is not performed. Fig. 12 shows a state in which ink flows from the liquid circulation chamber 2324 into the housing 231 via the orifice 2320, and pressure control of the ink pressure in the fluid chamber 2323 and the common supply channel 211 is performed. In Fig. 12, the lever 227 rotates in response to the displacement of the pressure receiving plate 2321, and as the lever 2327 rotates, the movable valve 2325 moves away from the orifice 2320 to open the orifice 2320.

[0050] As shown in FIG. 11, the lever 2327 is biased by a spring 2330, which is a biasing member, in a direction in which the movable valve 2325 closes the orifice 2320. The movable valve 2325 is provided downstream of the orifice 2320, that is, from the inside of the housing 231 so as to close the orifice 2320. One end of the spring 2330 is fitted into a cylindrical shaft portion 2340 formed in the housing 231, and the other end is fitted into a ring-shaped groove portion 2341 formed in the lever 2327. As a result, the direction in which the biasing force of the spring 2330 acts is a second direction D2 that intersects with the direction of gravity and is perpendicular to the first direction D1. Note that, as long as the ink can be prevented from sticking to the orifice 2320, the first direction D1 and the second direction D2 may intersect at an angle other than perpendicular. In addition, when the movable valve 2325 is in the closed position where it closes the orifice 2320, the orifice 2320, the movable valve 2325, the groove portion 2341, the spring 2330, and the shaft portion 2340 are arranged so that their centers are aligned on a straight line (line of action lb in the drawing).

[0051] One end of the spring 2326 is fitted to a cylindrical shaft portion 2342 formed on the housing 231, and the other end is fitted to the outer periphery of a circular ring-shaped protrusion portion 2343 formed on the pressure-receiving plate 2321. The spring 2326, the shaft portion 2342, and the protrusion portion 2343 are arranged so that their centers are aligned on a straight line lc.

[0052] When ink flows out from the negative pressure control unit 230a to the common supply flow channel 211, the pressure receiving plate 2321 moves downward in the drawing in response to a pressure fluctuation in the fluid chamber 2323 that occurs with a decrease in the amount of ink in the fluid chamber 2323. Then, when the pressure receiving plate 2321 abuts against the lever 2327, the lever 2327 rotates in a direction parallel to the drawing, with the abutment point 2327a as a force point and the abutment point 2327b between the rotation shaft 2328 and the fluid chamber 2323 (housing 231) as a fulcrum. Also, in response to the rotation of the lever 2327, the movable valve 2325 that has been closing the orifice 2320 moves in a direction (upward in the drawing) that creates a gap between the orifice 2320 and the movable valve 2325. Then, the ink stored in the liquid circulation chamber 2324 flows from the orifice 2320 through the gap between the movable valve 2325 and the orifice 2320 into the fluid chamber 2323. The pressure of the ink flowing into the fluid chamber 2323 is transmitted to the pressure receiving plate 2321. When the pressure receiving plate 2321 is pushed upward on the paper surface by the pressure of the ink flowing into the fluid chamber 2323, the pressure receiving plate 2321 The lever 2327 rotates in response to the displacement of the lever 2327. In addition, together with the rotation of the lever 2327, the movable valve 2325 moves toward the orifice 2320 (downward in the drawing), again closing the orifice 2320. The ink in the fluid chamber 2323 is discharged through the outlet 2331 to the common supply channel 211 on the downstream side.

[0053] Here, in the fluid chamber 2323, a position where the pressure-receiving plate 2321 acts on the movable valve 2325 via the lever 2327 to position the movable valve 2325 at a closed position corresponds to a first position of the pressure-receiving plate 2321. Also, a position where the pressure-receiving plate 2321 acts on the movable valve 2325 via the lever 2327 to position the movable valve 2325 at an open position corresponds to a second position of the pressure-receiving plate 2321. Also, the lever 2327 is a power transmission member that transmits the power that the pressure-receiving plate 2321 acts on the movable valve 2325 to move the movable valve 2325 to the open / closed position.

[0054] The spring 2326 applies a biasing force to the pressure receiving plate 2321 to position the pressure receiving plate 2321 at the first position. The pressure receiving plate 2321 is configured to be displaced from the first position to the second position in the second direction D2 against the biasing force when the magnitude of the pressure (negative pressure) in the fluid chamber 2323 becomes greater than the biasing force of the spring 2326. In this manner, the second position of the pressure receiving plate 2321 varies according to the pressure in the fluid chamber 2323. In addition, the orifice 2320 is formed so that the direction in which ink flows into the orifice 2320 intersects with the direction of gravity when the liquid ejection head 3 is attached to the recording apparatus 1000.

[0055] The fluid chamber 2323 is filled with ink, and the balance of the forces acting on the various parts inside the housing 231 is determined by the following relational expression (1). As shown in the expression (1), the balance of these forces utilizes the principle of leverage. At this time, as shown in FIG. 11 and FIG. 12, L 1 is the length perpendicular to the line of action (la in the drawing) of the force of the pressure plate 2321 pushing the lever 2327 from the fulcrum (2327b in the drawing), which is the contact point between the rotation shaft 2328 and the housing 231. 2 indicates the length perpendicular to the line of action (lb in the drawing) of the force pushing the center of the movable valve 2325 from the fulcrum (2327b in the drawing). At this time, by changing the spring constant of the spring 2326 which is the biasing member, the pressure due to the ink on the upstream side as viewed from the orifice 2320, that is, the pressure P 1 can be set to the desired pressure. (k d x d +P 2 S d )*L 1 =(-k v x v +(P 1 -P 2 )*S v )*L 2 (1 ) Here, in the plane in which the lever 2327 rotates as shown in FIGS. L 1: The distance perpendicular to the line of action of the force exerted by the pressure plate on the lever from the fulcrum L 2 : The distance perpendicular to the line of action of the force pushing the center of the movable valve from the fulcrum P 1 : Pressure due to ink upstream of the orifice P 2 : Pressure due to ink in the fluid chamber k d : Spring constant of spring 2326 in the fluid chamber x d : Spring displacement of spring 2326 in the fluid chamber k v : Spring constant of the spring 2330 that biases the movable valve x v : Spring displacement of the spring 2330 that biases the movable valve S d : Pressure receiving area of ​​the pressure plate from the ink S v : The area of ​​the movable valve that receives pressure from the ink

[0056] Here, the pressure receiving area S of the pressure receiving plate 2321 from the ink d is the pressure receiving area of ​​the pressure receiving plate 2321 receiving the pressure from the ink in the fluid chamber 2323, and corresponds to the area of ​​the pressure receiving plate 2321 when viewed from above in the displacement direction of the pressure receiving plate 2321 in FIG. 10A. In addition, the pressure receiving area S of the movable valve 2325 receiving the pressure from the ink v is the pressure receiving area of ​​the movable valve 2325 from the ink flowing in from the orifice 2320, and is the opening area of ​​the orifice 2320 in FIG. Equivalent to the mouth area.

[0057] Also, from equation (1), P 2 can be expressed by the following equation (2). P 2 =(-k d x d L 1 -k v x v L 2 +P 1 S v L 2 ) / (S d L 1 +Sv L 2 ) · · · (2)

[0058] Furthermore, if the valve resistance to ink by the movable valve 2325 is R and the flow rate of ink passing through the orifice 2320 is Q, the following equation (3) is established. P 2 =P 1 -QR···(3)

[0059] Here, the valve resistance R and the valve opening degree in the movable valve 2325 are designed to have the relationship shown in the graph of Fig. 13, for example. That is, the valve resistance R decreases as the valve opening degree of the movable valve 2325 increases. In addition, by determining the valve position so that the formula (2) and the formula (3) are simultaneously satisfied, P 2 is determined.

[0060] The pressure of the pressure source (not shown) connected upstream of the negative pressure control unit 230a is constant. Therefore, when the flow rate Q of the ink flowing into the negative pressure control unit 230a increases, the resistance between the negative pressure control unit 230a and the buffer tank 1003 increases by the amount of the increase in the flow rate Q. 1 As a result, the force P that opens the movable valve 2325 1 S v decreases, and as calculated from equation (2), P 2 increases instantly.

[0061] Furthermore, the following equation (4) is derived from equation (3). R=(P 1 -P 2 ) / Q···(4)

[0062] At this time, Q and P 2 increases, P 1Since decreases, R decreases. When R decreases, the valve opening of movable valve 2325 increases. As shown in FIG. 11, when the valve opening of movable valve 2325 increases, the length of spring 2330 decreases, and x, which is the displacement from the free length, increases. Therefore, the acting force kx of spring 2330 increases, and as calculated from equation (2), P 2 decreases instantly.

[0063] Also, P 2 If decreases instantaneously, the opposite effect to the above occurs and P 2 In this way, P 2 The instantaneous increase and decrease of is repeated, and the valve opening of the movable valve 2325 changes according to the ink flow rate Q. Then, when formulas (2) and (3) are established, P 2 As a result of the pressure being controlled to be approximately constant, the pressure due to the ink in the fluid chamber 2323 and therefore in the common supply flow channel 211 is also controlled to be approximately constant.

[0064] In this embodiment, as shown in FIG. 10B, the valve contact surface 2325a that contacts the housing 231 when the movable valve 2325 closes the orifice 2320 and the mounting surface 2329a of the rotating shaft 2328 of the bearing portion 2329 are arranged parallel to the direction of gravity. This suppresses malfunction of the movable valve 2325 caused by settling and adhesion of solid contents such as pigment components contained in the ink in the orifice 2320 and the gap between the movable valve 2325 and the orifice 2320. At this time, the closer the valve contact surface 2325a and the mounting surface 2329a of the rotating shaft 2328 are to the direction of gravity, the more the ink can be prevented from settling and adhering. In addition, a through hole may be formed in a part of the mounting surface 2329a to allow ink that has settled in the bearing portion 2329 to flow out of the bearing portion 2329. Furthermore, in this embodiment, if the ink contains titanium oxide, the effect of suppressing ink settling and adhesion by the negative pressure control unit 230 can be more significantly achieved. However, the ink used in this embodiment is not limited to ink containing titanium oxide, and various types of ink may be used.

[0065] In FIG. 11, the biasing members 2326 and 2330 are configured as two coupled springs. However, as long as the combined spring force satisfies a desired negative pressure value, the pressure adjustment function of the negative pressure control unit 230 is not affected, so a configuration using either one of the two springs 2326 and 2330 may be used. Also, the orifice 2320 is opened so that ink flows in a direction perpendicular to the direction of gravity to flow into the fluid chamber 2323. As shown in FIG. 11, the orifice 2320 opens into a wall surface 2350 that extends along a first direction D1 intersecting with the direction of gravity among the walls that form the fluid chamber 2323. Note that, within a range in which it is possible to avoid adhesion of ink in the orifice 2320, the direction in which ink flows into the orifice 2320 may have an angle with respect to the direction perpendicular to the direction of gravity, that is, may be a direction intersecting with the direction of gravity.

[0066] Next, a modified example of the negative pressure control unit according to the above embodiment will be described. In the following description, the same components as those in the above embodiment will be denoted by the same reference numerals, and detailed description will be omitted. Fig. 14 shows a cross section of a negative pressure control unit 3000 according to a first modified example, corresponding to Figs. 11 and 12. As shown in Fig. 14, in a state in which the liquid ejection head 3 is mounted on the recording device 1000, the negative pressure control unit 3000 has a configuration in which a plurality of the above negative pressure control units 230a (two in the illustrated example) are connected in a direction perpendicular to the direction of gravity.

[0067] The negative pressure control unit 3000 shown in FIG. 14 has two negative pressure control units 240 and 250. The negative pressure control units 240 and 250 have the same configuration as the negative pressure control unit 230a shown in FIG. 11 and FIG. 12. The negative pressure control units 240 and 250 are connected by being inverted upside down in the cross section shown in FIG. 14. The negative pressure control unit 3000 may be configured so that the negative pressure control units 240 and 250 control the pressure of ink of different colors. Alternatively, the negative pressure control unit 3000 may be configured so that the negative pressure control units 240 and 250 control ink of the same color to different negative pressures. The operations of the negative pressure control units 240 and 250 are similar to those of the negative pressure control unit 230a described above, and therefore detailed description thereof will be omitted here.

[0068] In addition, in FIG. 14, the negative pressure control units 240 and 250 are connected with the cross-sectional configuration shown in FIG. 14 inverted from each other, but the negative pressure control units 240, 250 may be configured to be joined together.

[0069] Next, a negative pressure control unit according to a second modified example will be described. FIG. 15 shows a cross section of the negative pressure control unit 4000 according to the second modified example, corresponding to FIG. 10B. FIG. 15 also shows the pressure receiving plate 2321 of the negative pressure control unit 4000. FIG. 15 also shows the negative pressure control unit 4000 in a state in which the liquid ejection head 3 is attached to the recording apparatus 1000. Each component of the negative pressure control unit 4000 is the same as each component of the negative pressure control unit 230 described above. In a state in which the liquid ejection head 3 is attached to the recording apparatus 1000, the pressure receiving plate 2321 of the negative pressure control unit 4000 is displaced in a direction perpendicular to the direction of gravity. In addition, in response to the displacement of the pressure receiving plate 2321, the lever 2327 rotates in a plane perpendicular to the direction of gravity. In addition, the orifice 2320 is opened so as to allow ink to flow in a direction perpendicular to the direction of gravity and to flow into the fluid chamber 2323.

[0070] 15, in plan view on a plane parallel to the direction of gravity, i.e., when the negative pressure control unit 4000 is viewed in the second direction D2, the opening center 2320a of the orifice 2320 is located lower in the direction of gravity than the center 2321a of the pressure-receiving plate 2321. By configuring the orifice 2320 and the pressure-receiving plate 2321 in this manner, even if air bubbles are mixed into the ink, the air bubbles are less likely to remain in the orifice 2320, and malfunction of the movable valve 2325 caused by adhesion of ink at the gas-liquid interface is reduced. Note that the separation distance D between the opening center 2320a of the orifice 2320 and the center 2321a of the pressure-receiving plate 2321 in the direction of gravity is 3 can be appropriately changed depending on the material of the ink used, the content of the ink pressure control by the negative pressure control unit 4000, and the like.

[0071] Next, a negative pressure control unit according to a third modified example will be described. In the above embodiment and modified examples, the liquid ejection head 3 may have a plurality of recording element substrates, and the negative pressure control unit may perform the above-mentioned ink pressure control on these recording element substrates. In this case, the common supply flow path 211 connected to the negative pressure control unit 230 is connected to a plurality of recording element substrates having a nozzle row 13a consisting of ejection ports 13. By providing a plurality of recording element substrates in the liquid ejection head 3, the number of ejection ports (nozzle rows) that eject ink also increases, and therefore the fluctuation in the amount of ink supplied to the ejection ports due to the printing density on the recorded matter also becomes larger. In controlling the pressure of the ink according to the fluctuation in the ink supply amount that increases as the number of recording element substrates of the liquid ejection head 3 increases, the above-mentioned pressure control unit can be used to appropriately control the inflow of ink by the movable valve according to the fluctuation in the ink in the fluid chamber.

[0072] The disclosure of this embodiment includes the following configuration. (Configuration 1) A discharge port for discharging a liquid; A supply path for supplying liquid to the ejection port; a pressure control unit for controlling a pressure of the liquid supplied from a liquid supply source to the supply path; having The pressure control unit includes: a fluid chamber having an inlet through which the liquid from the liquid supply source flows and an outlet through which the liquid having flowed in from the inlet flows out to the supply path; A valve body configured to be capable of taking a closed position that closes the inlet and an open position that opens the inlet; a movable member configured to be capable of taking a first position acting on the valve body to position the valve body at the closed position within the fluid chamber, and a second position acting on the valve body to position the valve body at the open position; a biasing member that applies a biasing force to the movable member to position the movable member at the first position; having a pressure in the fluid chamber that exceeds the biasing force of the biasing member, the movable member being moved from the first position to the second position; When the liquid ejection head is attached to a liquid ejection device that ejects the liquid onto a recording medium using the liquid ejection head, the direction in which the liquid flows into the inlet is a direction that intersects with the direction of gravity. A liquid ejection head comprising: (Configuration 2) the inlet opens into a wall surface that defines the fluid chamber and extends along a first direction that intersects with the direction of gravity, 2. The liquid ejection head according to configuration 1, wherein the valve body has an annular protrusion that abuts against the wall surface so as to surround the inlet when the valve body is in the closed position. (Configuration 3) 3. The liquid ejection head according to configuration 2, wherein the direction in which the urging force of the urging member acts is a second direction that intersects with the direction of gravity and is perpendicular to the first direction. (Configuration 4) 4. The liquid ejection head according to configuration 3, wherein the first direction and the second direction are each perpendicular to the direction of gravity. (Configuration 5) The pressure control unit includes: a power transmission member that is rotatable about a rotation axis perpendicular to both the first direction and the second direction, one end of which is capable of contacting the movable member and the other end of which is connected to the valve body, the movable member abuts against the one end when it moves from the first position to the second position against the biasing force due to the pressure in the fluid chamber, The power transmission member rotates in response to the displacement of the movable member in contact with the one end, thereby moving the valve body from a closed position to an open position. 5. The liquid ejection head according to configuration 4. (Configuration 6) 6. The liquid ejection head according to configuration 5, wherein the movable member is displaced in the second direction between the first position and the second position. (Configuration 7) When viewed in the second direction, the center of the opening of the inlet is located lower than the center of the movable member in the direction of gravity. 7. The liquid ejection head according to any one of configurations 3 to 6. (Configuration 8) 8. The liquid ejection head according to any one of configurations 1 to 7, wherein the liquid is an ink containing titanium oxide. (Configuration 9) 9. The liquid ejection head according to any one of configurations 1 to 8, wherein the supply path is connected to a plurality of recording element substrates each having a nozzle row made up of the ejection ports. (Configuration 10) A liquid ejection head as described in any one of configurations 1 to 9, characterized in that the two pressure control units are connected so that the direction in which the liquid flows into each of the inlets is the same. (Configuration 11) A liquid ejection head described in any one of configurations 1 to 9, characterized in that the two pressure control units are connected so that the directions in which the liquid flows into each of the inlets are opposite to each other. (Configuration 12) the biasing member is a first spring, and the movable member is biased by the first spring in a direction away from the power transmission member; the power transmission member is biased by a second spring in a direction to position the valve body at the closed position, The first spring constant is determined by the following formula (1): (k d x d +P 2 S d )*L 1 =(-k v x v +(P 1 -P 2 )*S v )*L 2 (1 ) Here, in the plane in which the power transmission member rotates, L 1 The length perpendicular to the line of action of the force of the movable member pushing the power transmission member from the fulcrum of the rotation of the power transmission member L 2 : The length perpendicular to the line of action of the force pushing the center of the valve body from the fulcrum P 1 : Pressure due to ink upstream of the inlet P 2 : Pressure due to ink in the fluid chamber k d : Spring constant of the first spring x d : Spring displacement of the first spring k v : Spring constant of the second spring x v : Spring displacement of the second spring S d : The pressure receiving area of ​​the movable member from the ink S v : Pressure receiving area of ​​the valve body from ink 6. The liquid ejection head according to configuration 5, (Configuration 13) 2. The liquid ejection head according to claim 1, wherein the second position of the movable member varies in response to a pressure in the fluid chamber. [Explanation of symbols]

[0073] 3 Liquid ejection head, 211 common supply flow path, 230 negative pressure control unit, 2320 orifice, 2321 pressure plate, 2323 fluid chamber, 2325 movable valve, 2326 spring, 2327 lever

Claims

1. A discharge port for discharging a liquid; A supply path for supplying liquid to the ejection port; a pressure control unit for controlling a pressure of the liquid supplied from a liquid supply source to the supply path; having The pressure control unit includes: a fluid chamber having an inlet through which the liquid from the liquid supply source flows and an outlet through which the liquid flowing in from the inlet flows out to the supply path; A valve body configured to be capable of taking a closed position that closes the inlet and an open position that opens the inlet; a movable member configured to be capable of assuming a first position acting on the valve body to position the valve body at the closed position within the fluid chamber, and a second position acting on the valve body to position the valve body at the open position; a biasing member that applies a biasing force to the movable member to position the movable member at the first position; having a pressure in the fluid chamber that exceeds the biasing force of the biasing member, the movable member being moved from the first position to the second position; When the liquid ejection head is attached to a liquid ejection device that ejects the liquid onto a recording medium using the liquid ejection head, the direction in which the liquid flows into the inlet is a direction that intersects with the direction of gravity. A liquid ejection head comprising:

2. The inlet opens to a wall surface that defines the fluid chamber and extends along a first direction that intersects with the direction of gravity, 2. The liquid ejection head according to claim 1, wherein the valve body has an annular projection that abuts against the wall surface so as to surround the inlet when the valve body is in the closed position.

3. 3. The liquid ejection head according to claim 2, wherein the biasing force of the biasing member acts in a second direction that intersects with the direction of gravity and is perpendicular to the first direction.

4. 4. The liquid ejection head according to claim 3, wherein the first direction and the second direction are each perpendicular to the direction of gravity.

5. The pressure control unit includes: a power transmission member that is rotatable about a rotation axis perpendicular to both the first direction and the second direction, one end of which is abuttable against the movable member and the other end of which is connected to the valve body, the movable member abuts against the one end when it moves from the first position to the second position against the biasing force due to the pressure in the fluid chamber, The power transmission member rotates in response to the displacement of the movable member in contact with the one end, thereby moving the valve body from a closed position to an open position.

5. The liquid ejection head according to claim 4.

6. The liquid ejection head according to claim 5 , wherein the movable member is displaced in the second direction between the first position and the second position.

7. When viewed in the second direction, the opening center of the inlet is located lower than the center of the movable member in the direction of gravity.

4. The liquid ejection head according to claim 3.

8. 2. The liquid ejection head according to claim 1, wherein the liquid is an ink containing titanium oxide.

9. 2. The liquid ejection head according to claim 1, wherein the supply path is connected to a plurality of recording element substrates each having a nozzle row made up of the ejection ports.

10. 2. The liquid ejection head according to claim 1, wherein the two pressure control units are connected such that the liquid flows into the inlets in the same direction.

11. 2. The liquid ejection head according to claim 1, wherein the two pressure control units are connected such that the liquid flows into the inlets in opposite directions.

12. the biasing member is a first spring, and the movable member is biased by the first spring in a direction away from the power transmission member; the power transmission member is biased by a second spring in a direction to position the valve body at the closed position, The first spring constant is determined by the following equation (1): (k ｄ x ｄ +P ２ S ｄ )*L １ =(-k ｖ x ｖ +(P １ -P ２ )*S ｖ )*L ２ ・・・(1 ） Here, in the plane in which the power transmission member rotates, L １ : The distance from the fulcrum of the rotation of the power transmission member perpendicular to the line of action of the force of the movable member pushing the power transmission member L ２ :The length perpendicular to the line of action of the force pushing the center of the valve body from the fulcrum P １ : Pressure due to ink upstream of the inlet P ２ : Pressure due to ink in the fluid chamber k ｄ : Spring constant of the first spring x ｄ : Spring displacement of the first spring k ｖ : Spring constant of the second spring x ｖ : spring displacement of the second spring S ｄ : Pressure receiving area of ​​the movable member from ink S ｖ :The area of ​​the valve body receiving pressure from the ink 6. The liquid ejection head according to claim 5,

13. 2. The liquid ejection head according to claim 1, wherein the second position of the movable member varies in response to a pressure in the fluid chamber.

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