Liquid ejection head and liquid ejection device

Abstract

To provide a liquid jet head that can be downsized and simplified in structure and whose valve can be forcibly opened, and a liquid jet device.SOLUTION: The liquid jet head comprises a liquid jet part that jets liquid, a first valve unit 60A that adjusts pressure of the liquid to be supplied to the liquid jet part, and an enclosure that stores the liquid jet part and the first valve unit. The first valve unit has: a first flow path 64A communicating with the liquid jet part; a first flexible film 63A which has a first inner surface 631A defining a portion of the first flow path and a first outer surface 632A which is a surface at the opposite side of the first inner surface and contacts atmospheric air, the first flexible film displaceable in a first direction from the first outer surface to the first inner surface and in a second direction which is opposite the first direction; and a first valve body 62A that moves between an open position where the first flow path is opened and a close position where the first flow path is closed, by the displacement of the first flexible film. The enclosure has a first opening part 73 formed at a position opposed to the first outer surface.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a liquid injection head that injects a liquid from a nozzle and a liquid injection device, and particularly to an inkjet recording head and an inkjet recording device that inject ink as the liquid.

Background Art

[0002] In a liquid injection head, a pressure adjustment unit that opens and closes the flow path to adjust the supply pressure of the liquid is provided in the middle of a flow path that supplies the liquid from a storage means in which the liquid is stored (see, for example, Patent Documents 1 and 2).

[0003] The pressure adjustment unit forms a part of the flow path with a diaphragm. When the liquid in the flow path becomes a negative pressure with respect to the atmospheric pressure, the diaphragm is deformed according to the pressure difference between the pressure of the liquid in the flow path and the atmospheric pressure outside the diaphragm, and the valve body is moved by the diaphragm to open and close the flow path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a liquid ejection head having a pressure adjustment unit such as Patent Document 1, it may be necessary to forcibly open the flow path in the pressure adjustment unit. The case where it is necessary to forcibly open the flow path in the pressure adjustment unit includes, for example, during pressure cleaning in which liquid is discharged from the nozzle by pressurizing the liquid from upstream of the pressure adjustment unit, and during initial filling in which the liquid is pressurized from upstream of the pressure adjustment unit and supplied to the liquid ejection head. Further, as other cases, for example, during a printing inspection in which the ejection characteristics of the liquid are confirmed by invalidating the valve function of the pressure adjustment unit and ejecting the liquid from the liquid ejection head to confirm the printing state, and the like can be mentioned.

[0006] However, when the pressure adjustment unit is disposed in the housing of the liquid ejection head as in Patent Document 2, in order to forcibly open the flow path blocked by the valve body, a mechanism for pressing the flexible film of the pressure adjustment unit by pressurizing and supplying air, or a mechanism for mechanically pressing the flexible film of the pressure adjustment unit using an eccentric cam or a drive rod needs to be disposed in the housing of the liquid ejection head. In order to secure a space for disposing such a mechanism in the housing of the liquid ejection head, there is a problem that the liquid ejection head becomes large-sized.

Means for Solving the Problems

[0007] An aspect of the present invention for solving the above problems includes a liquid ejection unit that ejects liquid, a first valve unit that adjusts the pressure of the liquid supplied to the liquid ejection unit, and a housing that houses the liquid ejection unit and the first valve unit. The first valve unit has a first flow path that communicates with the liquid ejection unit, a first inner surface that defines a part of the first flow path, and a first outer surface that is on the side opposite to the first inner surface and is in contact with the atmosphere. The first valve unit further has a first flexible film that is displaceable in a first direction from the first outer surface toward the first inner surface and a second direction opposite to the first direction, and a first valve body that moves between an open position where the first flow path is opened and a closed position where the first flow path is closed by the displacement of the first flexible film. The housing has a first opening formed at a position facing at least a part of the first outer surface. The liquid ejection head is characterized by the above.

[0008] Another aspect of the present invention is a liquid ejecting apparatus including the liquid ejecting head described in the above aspect and a liquid storage section that stores a liquid for supplying the liquid to the liquid ejecting head.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 4

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Figure 7

Figure 8

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Figure 10

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Figure 14

Embodiments for Carrying Out the Invention

[0010] The present invention will be described in detail based on embodiments below. However, the following description shows one aspect of the present invention and can be arbitrarily changed within the scope of the present invention. In each figure, the same reference numerals are used to indicate the same members, and the description is omitted as appropriate. Also, in each figure, X, Y, and Z represent three mutually orthogonal spatial axes. In this specification, the directions along these axes are referred to as the X direction, Y direction, and Z direction. The direction in which the arrow in each figure points is defined as the positive (+) direction, and the opposite direction of the arrow is defined as the negative (-) direction for explanation. Also, for the three spatial axes without limiting the positive and negative directions, they are described as the X axis, Y axis, and Z axis.

[0011] (Embodiment 1) FIG. 1 is a schematic diagram of the liquid ejection device according to Embodiment 1 of the present invention, viewed in the +Z direction. FIG. 2 is a schematic diagram of an inkjet recording device, which is a liquid ejection device, viewed in the +X direction.

[0012] As shown in the figure, an inkjet recording device I, which is an example of the "liquid ejection device" in the present embodiment, ejects and lands ink, which is a kind of liquid, onto a medium S such as printing paper, and performs printing such as an image (also called a recording operation) by the arrangement of dots formed on the medium S. As the medium S, in addition to recording paper, any material such as a resin film or cloth can be used. Also, the inkjet recording device I in the present embodiment is a so-called line-type recording device that performs printing by ejecting and landing ink from an inkjet recording head 10 onto the medium S while transporting the medium S with the inkjet recording head 10 fixed during printing.

[0013] The inkjet recording device I includes a head unit 1 having an inkjet recording head 10 (hereinafter also simply referred to as the recording head 10), which is an example of a "liquid ejection head", a supply member 2 that supplies ink to the head unit 1, a liquid storage unit 4 that stores ink, a device body 7, and a control unit 8.

[0014] The head unit 1 has a plurality of recording heads 10 capable of ejecting ink from nozzles 21 (see FIG. 7). The plurality of recording heads 10 are arranged side by side in a direction intersecting the +Y direction, which is the conveyance direction of the medium S, and in this embodiment, in the direction along the X axis. Details of the head unit 1 will be described later. Also, although the head unit 1 of this embodiment has a plurality of recording heads 10, the number of recording heads 10 constituting the head unit 1 is not particularly limited, and it may have one recording head 10. A supply member 2 is fixed to such a head unit 1. The ink supplied from the supply member 2 is supplied to each recording head 10 constituting the head unit 1.

[0015] The liquid storage unit 4 stores the ink to be supplied to the recording head 10. The ink stored in the liquid storage unit 4 is the ink that contributes to printing, that is, the ink ejected as droplets from the nozzles 21 of the recording head 10 to form an image or the like on the medium S. Examples of the liquid storage unit 4 include a cartridge detachable from the inkjet recording apparatus I, a bag-shaped pack formed of a flexible film, and a tank capable of replenishing liquid. In this embodiment, such a liquid storage unit 4 is fixed to the apparatus main body 7. Although not particularly shown, a plurality of types of inks different in color and type are individually stored in the liquid storage unit 4. Also, a sub-tank may be provided between the liquid storage unit 4 and the head unit 1. When the ink in the sub-tank decreases, the liquid storage unit 4 may replenish the sub-tank with the decreased amount of ink.

[0016] Ink from the liquid storage unit 4 is supplied to each recording head 10 of the head unit 1 through a supply pipe 4a such as a tube. Further, a pump 4b, which is a pressurizing mechanism for pressurizing and supplying the ink from the liquid storage unit 4 toward the recording head 10, is provided in the middle of the supply pipe 4a. Note that the pressurizing mechanism is not limited to the pump 4b, and may be a pressing mechanism that presses the liquid storage unit 4 from the outside or the like. Further, the pressurizing mechanism may use a head pressure difference generated by adjusting the vertical relative position between the recording head 10 and the liquid storage unit 4. In the present embodiment, the liquid storage unit 4 is fixed to the apparatus main body 7. However, for example, a liquid storage unit such as an ink cartridge may be mounted on the supply member 2, that is, on the -Z direction side of the supply member 2.

[0017] Further, the inkjet recording apparatus I may include a conveying unit. A first conveying unit 5 as an example of the conveying unit is provided on the -Y direction side of the inkjet recording apparatus I. The first conveying unit 5 includes a first conveying roller 501 and a first driven roller 502 that is driven by the first conveying roller 501. The first conveying roller 501 is provided on the back surface side of the medium S opposite to the landing surface where the ink lands, and is driven by the driving force of a first driving motor 503. Further, the first driven roller 502 is provided on the landing surface side of the medium S where the ink lands, and sandwiches the medium S with the first conveying roller 501. Such a first driven roller 502 presses the medium S toward the first conveying roller 501 by a biasing member such as a spring (not shown).

[0018] Further, a second conveying means 6 as an example of the conveying means is arranged in the +Y direction on the downstream side of the first conveying means 5 in the conveying direction of the medium S, and includes a conveying belt 601, a second drive motor 602, a second conveying roller 603, a second driven roller 604, and a tension roller 605. The second conveying roller 603 is driven by the driving force of the second drive motor 602. The conveying belt 601 is an endless belt and is wound around the outer circumferences of the second conveying roller 603 and the second driven roller 604. Such a conveying belt 601 is provided on the back surface side of the medium S. The tension roller 605 is provided between the second conveying roller 603 and the second driven roller 604, abuts against the inner circumferential surface of the conveying belt 601, and applies tension to the conveying belt 601 by the biasing force of a biasing member 606 such as a spring. Thereby, the surface of the conveying belt 601 that faces the recording head 10 between the second conveying roller 603 and the second driven roller 604 is flat.

[0019] The control unit 8 is the control section of the present embodiment. Although not particularly shown, for example, it includes a control device such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array) and a storage device such as a semiconductor memory. The control unit 8 comprehensively controls each element of the inkjet recording apparatus I, that is, the recording head 10, the first conveying means 5, the second conveying means 6, the pump 4b, etc. by the control device executing the program stored in the storage device. That is, the control unit 8 controls recording operations and the like. Further, the control unit 8 controls a pressing mechanism 80 (see FIG. 14) that forcibly opens the valve unit 60, which will be described in detail later, to open the valve unit flow path 64.

[0020] In such an inkjet recording apparatus I, while the medium S is conveyed by the first conveying means 5 and the second conveying means 6 toward the +Y direction with respect to the head unit 1, ink is ejected from the recording head 10 toward the +Z direction, and the ejected ink is made to land on the medium S to perform printing. The conveying means is not limited to the above-described first conveying means 5 and second conveying means 6, and those having a drum or the like may be used.

[0021] The head unit 1 will be described with reference to FIGS. 3 to 10. Note that FIG. 3 is an exploded perspective view of the supply member 2 and the head unit 1. FIG. 4 is a plan view of the head unit 1 viewed from the +Z direction. FIG. 5 is a perspective view of the recording head 10. FIGS. 6 and 7 are exploded perspective views of the recording head 10. FIG. 8 is a plan view of the recording head 10 viewed from the -Z direction. FIG. 9 is a cross-sectional view taken along line A-A' of FIG. 8. FIG. 10 is a cross-sectional view taken along line B-B' of FIG. 9.

[0022] As shown in FIGS. 3 and 4, the head unit 1 includes a plurality of recording heads 10 and a support 3 that supports the plurality of recording heads 10.

[0023] The support 3 is formed of a plate-like member, and support holes 3a for holding the plurality of recording heads 10 are provided. In the present embodiment, the support holes 3a are provided independently for each recording head 10. Of course, the support holes 3a may be provided continuously across the plurality of recording heads 10.

[0024] In the support holes 3a of such a support 3, the ejection surface of the recording head 10 is held in a state of protruding from the +Z direction side of the support 3. In the present embodiment, the surface of the recording head 10 facing the medium S is referred to as the ejection surface.

[0025] As shown in FIG. 4, the recording heads 10 held by such a support 3 are provided with a plurality of, in the present embodiment, three rows arranged along the X axis and two rows along the Y axis. That is, six recording heads 10 are held by one support 3.

[0026] Each recording head 10 is provided with fixing holes 11 at both ends in the +X direction and -X direction. The support 3 is provided with screw holes 3b for fixing each recording head 10. By inserting a screw 12 through the fixing hole 11 and screwing it into the screw hole 3b, each recording head 10 is fixed to the support 3.

[0027] Here, as shown in FIGS. 5 to 10, the recording head 10 includes a plurality of liquid ejection units 20 having nozzles 21 for ejecting ink, a holder 30 for holding the plurality of liquid ejection units 20, a fixing plate 40 for fixing the plurality of liquid ejection units 20, a flow path member 50 for supplying ink to the liquid ejection units 20, a valve unit 60 for supplying ink to the flow path member 50, and a cover 70 for housing the valve unit.

[0028] As shown in FIG. 8, nozzles 21 for ejecting ink are arranged in parallel along the X axis in the liquid ejection unit 20. Further, in the liquid ejection unit 20, a plurality of rows in which the nozzles 21 are arranged in parallel along the X axis are provided in a plurality of rows along the Y axis. In this embodiment, two rows are provided.

[0029] Inside the liquid ejection unit 20 (not shown) having such a structure, a flow path communicating with the nozzle 21 and pressure generating means for generating a pressure change in the ink in the flow path are provided. As the pressure generating means, for example, a piezoelectric actuator having a piezoelectric material exhibiting an electromechanical conversion function can be used to change the volume of the flow path by the deformation of the piezoelectric actuator, thereby generating a pressure change in the ink in the flow path and ejecting ink droplets from the nozzle 21. As other pressure generating means, a heat generating element can be arranged in the flow path, and ink droplets can be ejected from the nozzle 21 by bubbles generated by the heat generation of the heat generating element, or a so-called electrostatic actuator that generates an electrostatic force between a diaphragm and an electrode and deforms the diaphragm by the electrostatic force to eject ink droplets from the nozzle 21 can be used. Note that the surface where the nozzles 21 of the liquid ejection unit 20 open is the nozzle surface. That is, the ejection surface of the head unit 1 includes the nozzle surface on which the nozzles 21 are formed.

[0030] Also, a wiring board 22 connected to internal pressure generating means (not shown) is led out from the surface on the -Z direction side of the liquid ejection unit 20. The wiring board 22 can be a sheet-like flexible one, for example, a so-called flexible board such as a COF board. Further, for example, a switching element for driving the pressure generating means may be mounted on the wiring board 22, or the switching element may not be mounted. That is, the wiring board 22 may be a flexible wiring such as an FFC or an FPC.

[0031] As shown in FIGS. 7, 8, and 9, the holder 30 holds a plurality of liquid ejection units 20. Specifically, the holder 30 is provided with a housing portion 31 on the surface in the +Z direction. The housing portion 31 has a concave shape that opens on the surface in the +Z direction, and houses a plurality of liquid ejection units 20 fixed by a fixing plate 40. Further, the opening of the housing portion 31 is covered by the fixing plate 40. That is, the liquid ejection unit 20 is housed inside the space formed by the housing portion 31 and the fixing plate 40. The housing portion 31 is provided independently for each liquid ejection unit 20. Of course, the housing portion 31 may be provided continuously across a plurality of liquid ejection units 20. Further, the surface on the -Z direction side of the liquid ejection unit 20 is adhered to the bottom of the housing portion 31, that is, the surface on the -Z direction side of the inner surface of the housing portion 31 with an adhesive.

[0032] In such a holder 30, the liquid ejection units 20 are arranged in a staggered pattern along the X axis. Here, arranging the liquid ejection units 20 in a staggered pattern along the X axis means arranging the liquid ejection units 20 arranged side by side along the X axis alternately shifted in the Y axis direction. That is, the rows of the liquid ejection units 20 arranged side by side along the X axis are arranged in two rows along the Y axis, and the two rows of the liquid ejection units 20 are arranged with a half pitch shift along the X axis. By arranging the liquid ejection units 20 in a staggered pattern along the X axis in this way, the nozzles 21 of two liquid ejection units 20 can be partially overlapped along the X axis to form a continuous row of nozzles 21 along the direction along the X axis.

[0033] Further, on the +Z-direction side surface where the housing portion 31 of the holder 30 is provided, a recess 33 having a concave shape for fixing the fixing plate 40 is provided. The recess 33 has an opening sized and shaped such that the fixing plate 40 is fitted and fixed therein. The fixing plate 40 is made of a plate-like member and is fixed in the recess 33 of the holder 30 with an adhesive or the like. The fixing plate 40 is provided with an exposure opening 41 for exposing the nozzle 21 of each liquid ejection portion 20. In the present embodiment, the exposure opening 41 is provided independently for each liquid ejection portion 20. Note that the peripheral edge of the exposure opening 41 of the fixing plate 40 is fixed to the nozzle 21 side of the liquid ejection portion 20, that is, the +Z-direction side surface, with an adhesive or the like. The +Z-direction surface of the fixing plate 40 constitutes a part of the ejection surface.

[0034] Also, a flow path for flowing ink may be provided inside the holder 30 between the liquid ejection portion 20 and the flow path member 50. Of course, the flow path of the flow path member 50 and the flow path of the liquid ejection portion 20 may be directly connected without passing through the holder 30.

[0035] The holder 30 is provided with a wiring insertion hole 34 through which the wiring board 22 of the liquid ejection portion 20 is inserted. The wiring insertion hole 34 opens to the bottom surface of the housing portion 31, that is, the -Z-direction side surface of the housing portion 31, and is provided to open to the -Z-direction side surface of the holder 30.

[0036] On the -Z-direction side of the holder 30, a pair of flange portions 35 protruding in the +X direction and the -X direction, respectively, are provided. Fixing holes 11 through which the above-described screws 12 are inserted are provided to penetrate in the +Z direction in the flange portions 35.

[0037] Here, the shape of the recording head 10 in plan view as viewed in the -Z direction will be described with reference to FIG. 8. The recording head 10 includes a first portion P1 (the portion shown by hatching in FIG. 8), a second portion P2, and a third portion P3.

[0038] When the rectangle with the minimum area enclosing the recording head 10 is R, the long side E1 of the rectangle R overlaps with the side along the +X direction of the holder 30, and the short side E2 of the rectangle R overlaps with the side along the +Y direction of the holder 30. Let the center line parallel to the long side E1 of such a virtual rectangle R be LC.

[0039] The first part P1 is a rectangular part through which the center line LC passes. The second part P2 is a rectangular part protruding from the first part P1 in the -X direction. The third part P3 is a rectangular part protruding from the first part P1 in the +X direction. That is, the second part P2, the first part P1, and the third part P3 are arranged in this order along the X-axis in the +X direction.

[0040] The second part P2 and the third part P3 are located in opposite directions across the center line LC along the Y-axis. Then, a plurality of recording heads 10 are arranged along the X-axis such that the second part P2 of one recording head 10 and the third part P3 of the other recording head 10 face each other in the Y-axis direction. In this way, by arranging the second part P2 of one recording head 10 and the third part P3 of the other recording head 10 to face each other in the Y-axis direction, the nozzles 21 of the recording heads 10 adjacent to each other along the X-axis can be partially overlapped in the direction along the X-axis, and a continuous row of nozzles 21 can be formed across the X-axis. Note that the second part P2 and the third part P3 have a width along the Y-axis that does not pass through the center line LC. Therefore, when a plurality of recording heads 10 are arranged along the X-axis, the width in the direction along the Y-axis occupied by the plurality of recording heads 10 can be further narrowed, and the head unit 1 can be miniaturized in the direction along the Y-axis.

[0041] As shown in FIGS. 5 to 10, the flow path member 50 is fixed to the surface of the holder 30 on the -Z direction side. Inside the flow path member 50 (not shown), a flow path for supplying ink to the liquid ejection unit 20 is provided. The ink supplied from the liquid storage unit 4 is supplied to the flow path member 50 via the valve unit 60 and then supplied from the flow path member 50 to each liquid ejection unit 20. Note that the flow path provided inside the flow path member 50 may be branched. Further, a filter or the like for removing foreign matters such as bubbles contained in the ink may be provided in the middle of the flow path of the flow path member 50.

[0042] Also, on the surface of the flow path member 50 in the -Z direction, a valve unit 60 and a cover 70 are provided. A plurality of valve units 60 are provided corresponding to the number of liquid ejection units 20. That is, in the present embodiment, since four liquid ejection units 20 are provided in one recording head 10, four valve units 60 are also provided, the same number as the liquid ejection units 20. Note that the number of valve units 60 and the number of liquid ejection units 20 do not necessarily have to match. The four valve units 60 are arranged in two rows along the X axis and two rows along the Y axis, similar to the liquid ejection units 20. The two rows of liquid ejection units 20 provided along the Y axis are arranged at positions shifted from each other along the X axis. In the present embodiment, in the recording head 10, the valve units 60 located relatively in the -X direction and -Y direction among the four valve units 60 are referred to as the first valve unit 60A, and the valve units 60 located on the -X direction and +Y direction sides are referred to as the second valve unit 60B. Also, in the recording head 10, the valve units 60 located relatively in the +X direction and -Y direction among the four valve units 60 are referred to as the third valve unit 60C, and the valve units 60 located in the +X direction and +Y direction are referred to as the fourth valve unit 60D. Hereinafter, when the first valve unit 60A, the second valve unit 60B, the third valve unit 60C, and the fourth valve unit 60D are not distinguished, they are referred to as the valve unit 60.

[0043] Here, the valve unit 60 will be described with reference to FIGS. 11 to 13. Note that FIG. 11 is a side view of the valve unit 60 as viewed in the -W direction. FIGS. 12 and 13 are cross-sectional views taken along the line C-C' of FIG. 11. Further, FIG. 12 shows the valve-closed state, and FIG. 13 shows the valve-open state. Furthermore, in FIGS. 11 to 13, L, W, and H represent three mutually orthogonal spatial axes. In this specification, the directions along these axes are referred to as the L direction, the W direction, and the H direction. The direction in which the arrow in each figure points is defined as the positive (+) direction, and the opposite direction of the arrow is defined as the negative (-) direction for the description.

[0044] When the pressure on the liquid injection unit 20 side is equal to or higher than a predetermined pressure, the valve unit 60 closes the internal valve so as not to supply ink to the liquid injection unit side. When the pressure on the liquid injection unit side falls below the predetermined pressure, the internal valve opens, and the ink supplied from the liquid storage unit is supplied to the liquid injection unit side. The valve unit 60 can also be referred to as a "self-sealing valve" or a "differential pressure valve". The valve unit 60 also serves to separate the negative pressure state in the liquid injection unit from the positive pressure state on the liquid supply unit side so that the pressurized force from the liquid storage unit does not directly act on the liquid injection unit in the negative pressure state.

[0045] As shown in FIGS. 11 to 13, the valve unit 60 includes a valve unit main body 61, a valve body 62, and a flexible film 63. The valve unit 60 also has a valve unit flow path 64 that communicates with the liquid storage unit 4 and the liquid injection unit 20. The valve unit flow path 64 has a supply path 641 connected to the liquid storage unit 4, a liquid supply chamber 642 connected to the supply path 641, a discharge path 643 connected to the liquid injection unit 20 side, and a pressure chamber 644 connected to the discharge path. The liquid supply chamber 642 and the pressure chamber 644 are arranged side by side in this order in the +W direction, and the liquid supply chamber 642 and the pressure chamber 644 are separated by a flow path partition wall 65. A communication hole 651 that communicates the liquid supply chamber 642 and the pressure chamber 644 is formed in the flow path partition wall 65. That is, the ink from the liquid storage unit 4 is supplied to the liquid supply chamber 642 through the supply path 641. Also, the ink in the liquid supply chamber 642 is supplied to the pressure chamber 644 through the communication hole 651. Then, the ink in the pressure chamber 644 is supplied to the liquid injection unit 20 through the discharge path 643.

[0046] The pressure chamber 644 has a concave shape that opens to the +W-direction surface of the valve unit body 61. The pressure chamber 644 is sealed by a flexible film 63 fixed to the surface of the valve unit body 61. That is, the flexible film 63 defines a part of the pressure chamber 644. As the flexible film 63, a flexible material having resistance to ink can be used. Further, as the flexible film 63, it is preferable to use a material having a low water permeability and a low gas permeability such as liquid oxygen and nitrogen. Examples of the material of the flexible film 63 include a configuration in which a nylon film coated with vinylidene chloride (saran) is adhesively laminated to a high-density polyethylene film or a polypropylene (PP) film. Further, as other materials of the flexible film 63, polyethylene terephthalate (PET) or the like may be used. Further, as a method of joining the flexible film 63 to the valve unit body 61, for example, heat welding, vibration welding, adhesion with an adhesive, or the like can be used.

[0047] The inner surface of the pressure chamber 644 defined by this flexible film 63, that is, the surface on the -W-direction side is referred to as the inner surface 631, and the surface on the opposite side of the inner surface 631 of the flexible film 63, that is, the surface on the +W-direction side that is in contact with the atmosphere is referred to as the outer surface 632. Note that the inner surface 631 of the flexible film 63 refers to the portion of the flexible film 63 that defines the pressure chamber 644, that is, the portion that overlaps the +W-direction opening of the pressure chamber 644. Further, the outer surface 632 of the flexible film 63 refers to the portion that overlaps the inner surface 631 when viewed in the -W direction. That is, the inner surface 631 and the outer surface 632 of the flexible film 63 refer to regions that become so-called diaphragms that are displaced by the pressure difference between the inside and the outside of the pressure chamber 644. Note that the flexible film 63 is joined to the valve unit body 61 on the outside of the inner surface 631. Further, the flexible film 63 can be displaced in the -W direction and the +W direction opposite to the -W direction from the outer surface 632 toward the inner surface 631.

[0048] Furthermore, a pressure receiving plate 66 is disposed on the inner surface 631 of the flexible film 63. The pressure receiving plate 66 is made of a material having a higher Young's modulus than the flexible film 63, for example, a thin plate such as SUS or resin. In this embodiment, the pressure receiving plate 66 is a plate-like member having an outer diameter smaller than that of the inner surface 631 of the flexible film 63, and is joined to the inner surface of the flexible film 63, that is, the region defining the pressure chamber 644. Therefore, the pressure receiving plate 66 can move in the +W direction and the -W direction in accordance with the bending deformation of the flexible film 63. Note that the pressure receiving plate 66 is not particularly limited thereto, and one end of the pressure receiving plate 66 may be supported at the joint between the valve unit main body 61 and the flexible film 63. That is, the pressure receiving plate 66 may be bent and deformed like a leaf spring. When one end of the pressure receiving plate 66 is supported between the valve unit main body 61 and the flexible film 63 in this way, the pressure receiving plate 66 and the flexible film 63 may or may not be joined to each other.

[0049] The valve body 62 has a base end portion 621 accommodated in the liquid supply chamber 642, a shaft portion 622 protruding from the base end portion 621 toward the pressure chamber 644 through the communication hole 651, and an elastic member 623 provided on the +W direction side of the base end portion 621. The base end portion 621 has a substantially disk shape and is larger than the outer diameter in the cross section perpendicular to the +W direction of the shaft portion. The base end portion 621 can also be called a flange portion or a collar portion. The shaft portion 622 passes through the communication hole 651 formed in the flow path partition wall 65, and the tip portion thereof is located in the pressure chamber 644. The tip portion of the shaft portion 622 can contact the flexible film 63 defining a part of the pressure chamber 644 via the pressure receiving plate 66. The ink in the liquid supply chamber 642 flows into the pressure chamber 644 through the space between the shaft portion 622 and the inner surface of the communication hole 651. The elastic member 623 is provided inside the outer circumference of the base end portion 621 and outside the shaft portion 622 when viewed in the -W direction. A protrusion is formed at the portion where the elastic member 623 contacts the valve seat 652 on the +W direction side.

[0050] On the -W direction surface on the liquid supply chamber 642 side of the flow path partition 65, an annular valve seat 652 is provided around the communication hole 651. The valve seat 652 serves as a sealing portion that closes the communication hole 651 by contacting an elastic member 623 provided on the valve body 62. The valve seat 652 of the present embodiment is separate from the flow path partition 65 and is formed of a metal such as SUS or titanium, for example. Also, a liquid repellent treatment such as a fluorine coating may be applied to the -W direction surface where the elastic member 623 of the valve seat 652 contacts.

[0051] In the liquid supply chamber 642, a coil spring 67, which is an example of a biasing member, is interposed between the base end portion 621 of the valve body 62 and the valve unit main body 61 that defines the -W direction inner surface of the liquid supply chamber 642. The valve body 62 is biased in the +W direction by the coil spring 67. Note that, in addition to the coil spring 67, a leaf spring or a disc spring can be used as the biasing member, for example. Also, in the pressure chamber 644, a biasing member such as a coil spring that biases the flexible film 63 toward the +W direction with respect to the valve unit main body 61 may be provided.

[0052] The opening and closing operation of the valve unit 60 configured as described above will be described. In the following description, it is assumed that the liquid supply chamber 642 and the pressure chamber 644 are filled with ink due to the initial filling of ink into the nozzle 21 or the previous ejection of ink. As shown in FIG. 12, the coil spring 67 biases the valve body 62 in the +W direction, which is the direction in which the valve body 62 is always in the closed valve state. In the closed valve state where the valve body 62 is positioned in the +W direction, the elastic member 623 contacts the valve seat 652 and the communication hole 651 is closed, that is, the liquid supply chamber 642 and the pressure chamber 644 are in a non-communicating state. In the present embodiment, the position of the valve body 62 that closes the valve unit flow path 64 is referred to as the closed position. At the closed position of the valve body 62, the tip of the shaft portion 622 of the valve body 62 may or may not contact the pressure receiving plate 66.

[0053] When ink is ejected from the liquid ejection unit 20 while the liquid supply chamber 642 and the pressure chamber 644 are in a non - communicating state, the ink in the pressure chamber 644 decreases. As a result, as shown in FIG. 13, due to the differential pressure between the pressure on the outer surface 632 side of the flexible film 63, that is, the atmospheric pressure, the inside of the pressure chamber 644 becomes a negative pressure, and the flexible film 63 and the pressure receiving plate 66 are displaced so as to bend in the - W direction which is the liquid supply chamber 642 side. Then, the pressure receiving plate 66 pushes the tip of the shaft portion 622 in the - W direction, and the valve body 62 is pushed downward against the biasing force of the coil spring 67 toward the liquid supply chamber 642 side. As a result, due to the movement of the valve body 62 in the - W direction, the elastic member 623 is separated from the valve seat 652, and the valve body 62 is in an open - valve state. And when the valve body 62 is in the open - valve state, the communication hole 651 is in an open state, that is, the valve body 62 is in an open - valve state in which the liquid supply chamber 642 and the pressure chamber 644 are communicated. In the present embodiment, the position of the valve body 62 that opens the valve unit flow path 64 is referred to as the open position. That is, the valve body 62 moves between the closed position and the open position due to the displacement of the flexible film 63. At the open position of the valve body 62, the tip of the shaft portion 622 of the valve body 62 is in contact with the pressure receiving plate 66.

[0054] When the valve body 62 is in the open - valve state, the ink in the liquid supply chamber 642 flows into the pressure chamber 644 through the communication hole 651. When the pressure chamber 644 is sufficiently replenished with ink, the negative pressure in the pressure chamber 644 is eliminated, the flexible film 63 and the pressure receiving plate 66 return to their original positions, and the valve body 62 becomes in a closed - valve state as shown in FIG. 12 by the biasing force of the coil spring 67. In this way, by the opening and closing operation of the valve body 62, the ink in the pressure chamber 644 is always adjusted to have a substantially constant pressure.

[0055] Four such valve units 60 are arranged in the recording head 10. Here, the arrangement of the valve units 60 arranged in the recording head 10 with respect to the support 3 will be mainly described with reference to FIG. 10.

[0056] The first valve unit 60A is arranged such that the +H direction coincides with the -Z direction, the +W direction coincides with the +Y direction, and the +L direction coincides with the +X direction with respect to the flow path member 50. In such a first valve unit 60A, the valve unit flow path 64 of the valve unit 60 described above becomes the "first flow path 64A" that communicates with the liquid injection unit 20. Further, the flexible film 63 of the valve unit 60 becomes the "first flexible film 63A" in the first valve unit 60A. Also, the pressure receiving plate 66 of the valve unit 60 becomes the "first pressure receiving plate 66A" in the first valve unit 60A. Further, the valve body 62 of the valve unit 60 becomes the "first valve body 62A" in the first valve unit 60A. And the inner surface 631 of the first flexible film 63A in the first valve unit 60A becomes the "first inner surface 631A", and the outer surface 632 of the first flexible film 63A becomes the "first outer surface 632A". The -W direction from the first outer surface 632A toward the first inner surface 631A coincides with the -Y direction. Hereinafter, the first direction from the first outer surface 632A toward the first inner surface 631A will be described as the -Y direction. Also, the +W direction, which is the direction opposite to the -W direction, coincides with the +Y direction. Hereinafter, the second direction will be described as the +Y direction. Further, the third direction, which is orthogonal to the -Y direction, which is the first direction, is the direction along the X-axis and the direction along the Z-axis, but in the present embodiment, the third direction is the +X direction that is orthogonal to the injection direction, which is the +Z direction. Hereinafter, in the present embodiment, the third direction will be described as the +X direction.

[0057] In the second valve unit 60B, the +H direction coincides with the -Z direction, the +W direction coincides with the -Y direction, and the +L direction coincides with the -X direction with respect to the flow path member 50. That is, the second valve unit 60B is arranged such that the valve unit 60 is rotated 180 degrees about a virtual axis along the +H direction with respect to the first valve unit 60A. In such a second valve unit 60B, the valve unit flow path 64 of the valve unit 60 described above becomes the "second flow path 64B" that communicates with the liquid injection unit 20. Also, the flexible film 63 of the valve unit 60 becomes the "second flexible film 63B" in the second valve unit 60B. Further, the pressure receiving plate 66 of the valve unit 60 becomes the "second pressure receiving plate 66B" in the second valve unit 60B. Also, the valve body 62 of the valve unit 60 becomes the "second valve body 62B" in the second valve unit 60B. And the inner surface 631 of the second flexible film 63B in the second valve unit 60B becomes the "second inner surface 631B", and the outer surface 632 of the second flexible film 63B becomes the "second outer surface 632B". In such a second valve unit 60B, it is arranged such that the direction from the second outer surface 632B to the second inner surface 631B is the +Y direction, which is the second direction, and the direction from the second inner surface 631B to the second outer surface 632B is the -Y direction, which is the first direction.

[0058] The third valve unit 60C is held by the flow path member 50 in the same posture as the first valve unit 60A. That is, the third valve unit 60C is arranged such that the +H direction coincides with the -Z direction, the +W direction coincides with the +Y direction, and the +L direction coincides with the +X direction with respect to the flow path member 50. In such a third valve unit 60C, the valve unit flow path 64 of the valve unit 60 becomes the "third flow path 64C" communicating with the liquid injection unit 20. Also, the flexible film 63 of the valve unit 60 becomes the "third flexible film 63C" in the third valve unit 60C. Further, the pressure receiving plate 66 of the valve unit 60 becomes the "third pressure receiving plate 66C" in the third valve unit 60C. Also, the valve body 62 of the valve unit 60 becomes the "third valve body 62C" in the third valve unit 60C. And the inner surface 631 of the third flexible film 63C in the third valve unit 60C becomes the "third inner surface 631C", and the outer surface 632 of the third flexible film 63C becomes the "third outer surface 632C". In such a third valve unit 60C, it is arranged such that the direction from the third outer surface 632C to the third inner surface 631C is the first direction, which is the -Y direction, and the direction from the third inner surface 631C to the third outer surface 632C is the second direction, which is the +Y direction.

[0059] The fourth valve unit 60D is held by the flow path member 50 in the same posture as the second valve unit 60B. That is, in the fourth valve unit 60D, the +H direction coincides with the -Z direction, the +W direction coincides with the -Y direction, and the +L direction coincides with the -X direction with respect to the holder 30. In such a fourth valve unit 60D, the valve unit flow path 64 of the valve unit 60 described above becomes the "fourth flow path 64D" communicating with the liquid injection unit 20. Also, the flexible film 63 of the valve unit 60 becomes the "fourth flexible film 63D" in the fourth valve unit 60D. Further, the pressure receiving plate 66 of the valve unit 60 becomes the "fourth pressure receiving plate 66D" in the fourth valve unit 60D. Also, the valve body 62 of the valve unit 60 becomes the "fourth valve body 62D" in the fourth valve unit 60D. And the inner surface 631 of the fourth flexible film 63D in the fourth valve unit 60D becomes the "fourth inner surface 631D", and the outer surface 632 of the fourth flexible film 63D becomes the "fourth outer surface 632D". In such a fourth valve unit 60D, it is arranged such that the direction from the fourth outer surface 632D to the fourth inner surface 631D is the +Y direction, which is the second direction, and the direction from the fourth inner surface 631D to the fourth outer surface 632D is the -Y direction, which is the first direction.

[0060] Here, as shown in FIGS. 6 and 9, the first valve unit 60A and the second valve unit 60B are arranged at the same position in the +Z direction. Also, the second valve unit 60B and the third valve unit 60C are arranged at the same position in the +Z direction. Further, the third valve unit 60C and the fourth valve unit 60D are arranged at the same position in the +Z direction. That is, in the present embodiment, the first valve unit 60A, the second valve unit 60B, the third valve unit 60C, and the fourth valve unit 60D are arranged at the same position in the +Z direction. Note that two members being arranged at the same position in the +Z direction means that the central coordinates of the two members along the Z-axis are at the same position on the Z-axis. By arranging all the valve units 60 at the same position in the +Z direction in this way, the miniaturization of the recording head 10 in the +Z direction can be achieved. Of course, the first valve unit 60A, the second valve unit 60B, the third valve unit 60C, and the fourth valve unit 60D may be arranged at different positions in the +Z direction relative to one another, with one or more of them being different.

[0061] Also, as shown in FIG. 10, the second valve unit 60B is displaced in the +Y direction, which is the second direction, and the +X direction, which is the third direction, with respect to the first valve unit 60A so as to overlap a part of the first valve unit 60A when viewed in the -Y direction, which is the first direction. That is, when viewed in the -Y direction, the -X direction end portion of the second valve unit 60B is arranged to overlap the +X direction end portion of the first valve unit 60A. Also, when viewed in the -Y direction, the +X direction end portion of the second valve unit 60B does not overlap the first valve unit 60A, and the -X direction end portion of the first valve unit 60A is arranged at a position where it does not overlap the second valve unit 60B.

[0062] Further, at least a part of the first outer surface 632A of the first valve unit 60A does not overlap with the second valve unit 60B when viewed in the -Y direction. In the present embodiment, the first outer surface 632A and the second valve unit 60B partially overlap when viewed in the -Y direction. That is, in the present embodiment, when viewed in the -Y direction, the +X-direction end portion of the first outer surface 632A overlaps with the second valve unit 60B, and the -X-direction end portion does not overlap with the second valve unit 60B. Of course, the first outer surface 632A and the second valve unit 60B may be arranged at positions where they do not completely overlap when viewed in the -Y direction. However, by arranging the first outer surface 632A and the second valve unit 60B so that they partially overlap when viewed in the -Y direction, the miniaturization of the recording head 10 in the +X direction can be achieved.

[0063] Furthermore, at least a part of the second outer surface 632B of the second valve unit 60B does not overlap with the first valve unit 60A when viewed in the +Y direction. In the present embodiment, the second outer surface 632B and the first valve unit 60A partially overlap when viewed in the +Y direction. That is, in the present embodiment, when viewed in the +Y direction, the -X-direction end portion of the second outer surface 632B overlaps with the first valve unit 60A, and the +X-direction end portion does not overlap with the second valve unit 60B. Of course, the second outer surface 632B and the first valve unit 60A may be arranged so that they do not completely overlap when viewed in the +Y direction. However, by arranging the second outer surface 632B and the first valve unit 60A so that they partially overlap when viewed in the +Y direction, the miniaturization of the recording head 10 in the +X direction can be achieved.

[0064] Further, at least a part of the second outer surface 632B of the second valve unit 60B does not overlap with the third valve unit 60C when viewed in the +Y direction. In the present embodiment, the second outer surface 632B and the third valve unit 60C partially overlap when viewed in the +Y direction. That is, in the present embodiment, when viewed in the +Y direction, the +X-direction end of the second outer surface 632B overlaps with the third valve unit 60C, and the -X-direction end does not overlap with the third valve unit 60C. Of course, the second outer surface 632B and the third valve unit 60C may be arranged so as not to completely overlap when viewed in the +Y direction. However, by arranging the second outer surface 632B and the third valve unit 60C so that they partially overlap when viewed in the +Y direction, miniaturization of the recording head 10 in the +X direction can be achieved.

[0065] That is, the second outer surface 632B of the second flexible film 63B of the second valve unit 60B overlaps both the first valve unit 60A and the third valve unit 60C when viewed in the +Y direction.

[0066] The third valve unit 60C is arranged in the +X direction, which is the third direction, with respect to the first valve unit 60A. In the present embodiment, the first valve unit 60A and the third valve unit 60C are arranged at the same position in the +Y direction and at different positions in the +X direction. That is, the first valve unit 60A is arranged in the -X direction with respect to the third valve unit 60C, and the third valve unit 60C is arranged in the +X direction with respect to the first valve unit 60A. Of course, the first valve unit 60A and the third valve unit 60C may be arranged so as to be displaced in the direction along the Y-axis with respect to each other. However, by arranging the first valve unit 60A and the third valve unit 60C at positions where at least a part of them overlaps when viewed in the +X direction, miniaturization of the recording head 10 in the +Y direction can be achieved.

[0067] Further, the third valve unit 60C is arranged so as to overlap a part of the second valve unit 60B when viewed in the +Y direction, which is the second direction. That is, when viewed in the +Y direction, a part in the -X direction of the third valve unit 60C and a part in the +X direction of the second valve unit 60B are arranged so as to overlap each other.

[0068] Also, a part of the third outer surface 632C of the third valve unit 60C does not overlap with the second valve unit 60B when viewed in the -Y direction. In the present embodiment, the third outer surface 632C and the second valve unit 60B partially overlap when viewed in the -Y direction. That is, in the present embodiment, the third outer surface 632C overlaps with the second valve unit 60B at the -X direction end portion when viewed in the -Y direction, and does not overlap with the second valve unit 60B at the +X direction end portion. Of course, the third outer surface 632C and the second valve unit 60B may be arranged so as not to completely overlap when viewed in the -Y direction. However, by arranging the third outer surface 632C and the second valve unit 60B so that they partially overlap when viewed in the +X direction, the miniaturization of the recording head 10 in the +Y direction can be achieved.

[0069] Also, the third valve unit 60C is arranged so as to overlap with a part of the fourth valve unit 60D when viewed in the +Y direction. That is, when viewed in the +Y direction, a part of the +X direction of the third valve unit 60C and a part of the -X direction of the fourth valve unit 60D are arranged so as to overlap each other.

[0070] Also, at least a part of the third outer surface 632C of the third valve unit 60C does not overlap with the fourth valve unit 60D when viewed in the -Y direction. In the present embodiment, the third outer surface 632C and the fourth valve unit 60D partially overlap when viewed in the -Y direction. That is, in the present embodiment, the third outer surface 632C overlaps with the fourth valve unit 60D at the +X direction end portion when viewed in the -Y direction, and does not overlap with the fourth valve unit 60D at the -X direction end portion. Of course, the third outer surface 632C and the fourth valve unit 60D may be arranged so as not to completely overlap when viewed in the +X direction. However, by arranging the third outer surface 632C and the fourth valve unit 60D so that they partially overlap when viewed in the -Y direction, the miniaturization of the recording head 10 in the +Y direction can be achieved.

[0071] That is, the third outer surface 632C of the third valve unit 60C overlaps with the second valve unit 60B and the fourth valve unit 60D when viewed in the -Y direction.

[0072] The fourth valve unit 60D is arranged in the +Y direction, which is the third direction with respect to the second valve unit 60B. In the present embodiment, the second valve unit 60B and the fourth valve unit 60D are arranged at the same position in the +Y direction and at different positions in the +X direction. That is, the second valve unit 60B is arranged in the -X direction with respect to the fourth valve unit 60D, and the fourth valve unit 60D is arranged in the +X direction with respect to the second valve unit 60B. Of course, the second valve unit 60B and the fourth valve unit 60D may be arranged offset in the direction along the Y-axis. However, by arranging the second valve unit 60B and the fourth valve unit 60D at positions where at least a part overlaps when viewed in the +X direction, miniaturization in the +Y direction can be achieved.

[0073] Also, the fourth valve unit 60D is arranged so as to overlap a part of the third valve unit 60C when viewed in the +Y direction, which is the second direction as described above. That is, when viewed in the +Y direction, a part in the -X direction of the fourth valve unit 60D and a part in the +X direction of the third valve unit 60C are arranged to overlap each other.

[0074] Also, at least a part of the fourth outer surface 632D of the fourth valve unit 60D does not overlap the third valve unit 60C when viewed in the +Y direction. In the present embodiment, the fourth outer surface 632D and the third valve unit 60C partially overlap when viewed in the +Y direction. That is, in the present embodiment, the fourth outer surface 632D overlaps the third valve unit 60C at the end in the -X direction and does not overlap the third valve unit 60C at the end in the +X direction when viewed in the +Y direction. Of course, the fourth outer surface 632D and the third valve unit 60C may be arranged so as not to completely overlap when viewed in the +Y direction. However, by arranging the fourth outer surface 632D and the third valve unit 60C so that they partially overlap when viewed in the +Y direction, miniaturization in the +X direction of the recording head 10 can be achieved.

[0075] As described above, in the case where the four valve units 60 of the present embodiment are viewed in the direction along the Y-axis, a part of the first outer surface 632A overlaps with a part of the second valve unit 60B, a part of the second outer surface 632B overlaps with a part of the first valve unit 60A and the third valve unit 60C, a part of the third outer surface 632C overlaps with a part of the second valve unit 60B and the fourth valve unit 60D, and a part of the fourth outer surface 632D overlaps with a part of the third valve unit 60C. For this reason, when viewed in the direction along the Y-axis, compared with the case where the outer surface 632 of one valve unit 60 and other valve units 60 are arranged so as not to overlap, miniaturization in the direction along the X-axis of the recording head 10 can be achieved.

[0076] In the present embodiment, when viewed in the direction along the Z-axis, a part of the first valve unit 60A, the second valve unit 60B, the third valve unit 60C, and a part of the fourth valve unit 60D overlap with the first portion P1, a part of the first valve unit 60A overlaps with the second portion P2, and a part of the fourth valve unit 60D overlaps with the third portion P3.

[0077] In addition, the four valve units 60 arranged as such are covered by a cover 70. The cover 70 is fixed to the -Z direction surface of the flow path member 50 and covers the valve unit 60 between it and the flow path member 50. Specifically, a valve unit accommodation portion 71 that opens in the +Z direction is formed in the cover 70. The valve unit accommodation portion 71 has a concave shape that opens on the +Z direction surface, and the +Z direction opening of the valve unit accommodation portion 71 is covered by the flow path member 50. The valve unit accommodation portion 71 is provided independently for each valve unit 60, and one valve unit 60 is accommodated in each of the valve unit accommodation portions 71. That is, the "housing" that houses the liquid injection portion 20 and the valve unit 60 is constituted by the fixing plate 40, the holder 30, the flow path member 50, and the cover 70 in the present embodiment. Note that the cover 70 may be divided into two or more pieces. Further, since the valve unit accommodation portion 71 is provided independently for each valve unit 60, a first partition wall 72A, which is a partition wall, is provided between the valve unit accommodation portion 71 that houses the first valve unit 60A of the cover 70 and the valve unit accommodation portion 71 that houses the third valve unit 60C. Similarly, a second partition wall 72B, which is a partition wall, is provided between the valve unit accommodation portion 71 that houses the second valve unit 60B and the valve unit accommodation portion 71 that houses the fourth valve unit 60D.

[0078] The cover 70 has a first opening 73 formed at a position facing at least a part of the first outer surface 632A of the first valve unit 60A. The first opening 73 penetrates the cover 70 along the Y-axis and communicates the inside and the outside of the valve unit housing portion 71. That is, a part of the first outer surface 632A of the first valve unit 60A is exposed to the outside through the first opening 73 provided in the cover 70. In this way, by exposing the first outer surface 632A of the first flexible film 63A to the outside of the cover 70, that is, to the outside of the valve unit housing portion 71, the first flexible film 63A can be pressed from the outside of the cover 70 in the -Y direction, which is the first direction. Therefore, even if the differential pressure between the pressure on the first inner surface 631A side and the pressure on the first outer surface 632A side of the pressure chamber 644 of the first valve unit 60A, that is, the so-called atmospheric pressure, is not equal to or higher than a predetermined pressure, the first flexible film 63A can be moved in the -Y direction to move the first valve body 62A in the -X direction, and the liquid supply chamber 642 and the pressure chamber 644 of the first flow path 64A can be brought into a valve-opening state in which they communicate with each other. In the present embodiment, an operation of pressing the outer surface 632 of the flexible film 63 in the valve unit 60 by an external force other than the pressure difference between the inner surface 631 and the outer surface 632 to move the valve body 62 to open the valve is referred to as forced valve opening.

[0079] Forced valve opening is performed, for example, in a so-called initial filling operation of filling an empty recording head 10 filled with no ink used for printing with the ink used for printing, or a cleaning operation of discharging ink from the nozzles 21. By providing the first opening 73 in this way, the first flexible film 63A can be operated from the outside of the cover 70. Therefore, it is not necessary to provide a mechanism or the like for operating the first flexible film 63A inside the cover 70, that is, inside the valve unit housing portion 71. This makes it possible to reduce the size of the recording head 10 and simplify its structure, and to easily perform forced valve opening.

[0080] Note that it is preferable that the first opening 73 overlaps at least a part of the first valve body 62A when viewed in the -Y direction which is the first direction. In the present embodiment, a part on the +X direction side of the first opening 73 is disposed at a position overlapping the -X direction side of the first valve body 62A. By providing the first opening 73 so as to overlap the first valve body 62A when viewed in the -Y direction in this way, when the first flexible film 63A is pressed in the -Y direction to forcibly open the valve, the movement of the valve body 62 in the -Y direction can be stabilized. Incidentally, when forcibly opening the valve, by pressing the first flexible film 63A at a position as close as possible to the shaft portion 622 of the first valve body 62A, the force applied to the shaft portion 622 in a direction inclined with respect to the Y axis can be reduced, so that the valve body 62 can be stably moved along the Y axis. Therefore, it is more preferable that the first opening 73 is disposed so as to overlap the shaft portion 622 of the first valve body 62A when viewed in the -Y direction.

[0081] Further, it is preferable that the first opening 73 overlaps at least a part of the first pressure receiving plate 66A when viewed in the -Y direction which is the first direction. When the first opening 73 is provided at a position overlapping the first pressure receiving plate 66A, the first opening 73 may or may not overlap at least a part of the first valve body 62A when viewed in the -Y direction. By providing the first opening 73 so as to overlap the first pressure receiving plate 66A when viewed in the -Y direction in this way, when the first flexible film 63A is pressed in the -Y direction through the first opening 73, the pressure receiving plate 66 can be pressed, and the movement of the first valve body 62A moving by the first pressure receiving plate 66A can be stabilized. For this reason, forced valve opening can be performed stably.

[0082] Further, as described above, the first valve unit 60A is disposed so that a part thereof does not overlap the second valve unit 60B when viewed in the -Y direction. For this reason, the first opening 73 can be formed to be relatively wide in the -Y direction at a position in the -Y direction of the second valve unit 60B.

[0083] Also, among the inner wall surfaces 71a forming the valve unit housing portion 71 of the cover 70, at a position different from the first opening 73, the gap t1 between the portion facing the first outer surface 632A and the first outer surface 632A is preferably smaller than the dimension W1 of the first valve unit 60A in the -Y direction. Further, it is more preferable that the gap t1 is smaller than 1 / 2 of the dimension W1 of the first valve unit 60A. Here, the gap t1 between the portion of the inner wall surface 71a facing the first outer surface 632A and the first outer surface 632A is the minimum dimension in the state where the first flexible film 63A is most displaced in the +Y direction. Also, the dimension W1 of the first valve unit 60A in the -Y direction is the maximum dimension in the state where the first flexible film 63A is most displaced in the +Y direction. By making the gap t1 between the first outer surface 632A and the inner wall surface 71a smaller than the dimension W1 of the first valve unit 60A in the -Y direction in this way, the recording head 10 can be miniaturized in the +Y direction.

[0084] Also, among the inner wall surfaces 71a forming the valve unit housing portion 71 of the cover 70, at a position different from the first opening 73 and facing the first outer surface 632A, the gap t1 between the portion and the first outer surface 632A is preferably smaller than the maximum displacement amount D1 (see FIG. 13) of the first flexible film 63A in the -Y direction. Here, the maximum displacement amount D1 of the first flexible film 63A in the -Y direction is the dimension between the portion that is most located in the -Y direction when the first flexible film 63A is displaced in the -Y direction and the portion that is most located in the +Y direction when the first flexible film 63A is displaced in the +Y direction. By making the gap t1 between the first outer surface 632A and the inner wall surface 71a smaller than the maximum displacement amount D1 of the first flexible film in this way, the recording head 10 can be miniaturized in the +Y direction.

[0085] The cover 70 has a second opening 74 formed at a position facing at least a part of the second outer surface 632B of the second valve unit 60B. The second opening 74 penetrates the cover 70 along the Y-axis and communicates the inside and the outside of the valve unit housing portion 71. That is, a part of the second outer surface 632B of the second valve unit 60B is exposed to the outside through the second opening 74 provided in the cover 70. In this way, by exposing the second outer surface 632B of the second flexible film 63B to the outside of the cover 70 through the second opening 74, the second flexible film 63B can be pressed from the outside of the cover 70 in the +Y direction. Therefore, the second valve unit 60B can be forcibly opened from the outside of the cover 70.

[0086] Also, as described above, at least a part of the second outer surface 632B of the second valve unit 60B does not overlap with the first valve unit 60A when viewed in the +Y direction. Also, at least a part of the second outer surface 632B does not overlap with the third valve unit 60C when viewed in the +Y direction. For this reason, the second opening 74 is provided at a position that does not overlap with the first valve unit 60A and the third valve unit 60C of the second outer surface 632B when viewed in the +Y direction. That is, the second opening 74 is provided between the first valve unit 60A and the third valve unit 60C. Specifically, the second opening 74 is provided to penetrate in the direction along the Y-axis through the first partition wall 72A between the valve unit housing portion 71 that houses the first valve unit 60A and the valve unit housing portion 71 that houses the third valve unit 60C. The second opening 74 is formed so as to have the same opening area in the direction along the Y-axis. Also, the dimension of the first partition wall 72A in the direction along the Y-axis, that is, the length L2 of the second opening 74 along the Y-axis, is larger than the maximum width W1 of the valve unit 60 along the Y-axis. The maximum width W1 of the valve unit 60 along the Y-axis is the maximum dimension in a state where the flexible film 63 is displaced maximally toward the side opposite to the valve unit body 61.

[0087] Here, the distance L1 from one end to the other end of the first opening 73 is shorter than the distance L2 from one end to the other end of the second opening 74. That is, it is configured to satisfy L1 < L2. Note that the distance L1 from one end to the other end of the first opening 73 is the distance from the opening in the -Y direction to the opening in the +Y direction along the Y-axis of the first opening 73. Similarly, the distance L2 from one end to the other end of the second opening 74 is the distance from the opening in the -Y direction to the opening in the +Y direction along the Y-axis of the second opening 74.

[0088] Also, the area of the first opening 73 is preferably larger than the area of the second opening 74. Here, the areas of the first opening 73 and the second opening 74 are the areas of the opening portions on the outer surface of the cover 70. Since the first outer surface 632A has a portion not covered by the second valve unit 60B when viewed in the -Y direction and the valve unit 60 is not arranged in the -X direction from the second valve unit 60B, the first opening 73 can be provided with an extended width Wa in the -X direction. In contrast, the second outer surface 632B overlaps both the first valve unit 60A and the third valve unit 60C when viewed in the +Y direction, and since the second opening 74 is provided in the first partition wall 72A, the width Wb along the X-axis of the second opening 74 is relatively small. Therefore, since the width Wa in the direction along the X-axis of the first opening 73 can be made larger than the width Wb of the second opening 74, the area of the first opening 73 can be made larger than the area of the second opening 74 provided in the first partition wall 72A.

[0089] Also, among the inner wall surfaces 71a of the cover 70, the gap t1 between the portion that is at a position different from the first opening 73 and faces the first outer surface 632A and the first outer surface 632A is preferably smaller than the distance t2 between the first valve unit 60A and the second valve unit 60B in the -Y direction. That is, it is preferable to satisfy t1 < t2. The distance t2 in the -Y direction between the first valve unit 60A and the second valve unit 60B is the distance in the -Y direction between the position when the first flexible film 63A is displaced maximally toward the side opposite to the valve unit body 61 of the first valve unit 60A and the position when the second flexible film 63B is displaced maximally toward the side opposite to the valve unit body 61 of the second valve unit 60B. By making the gap t1 smaller than the distance t2 in this way, miniaturization in the direction along the Y-axis of the recording head 10 can be achieved.

[0090] Also, similar to the above-described first opening 73, the second opening 74 preferably overlaps at least a part of the second valve body 62B when viewed in the +Y direction. Further, the second opening 74 preferably overlaps at least a part of the second pressure receiving plate 66B when viewed in the +Y direction. By providing the second opening 74 at a position overlapping the second valve body 62B or the second pressure receiving plate 66B when viewed in the +Y direction in this way, when the second flexible film 63B is pressed from the outside of the cover 70 through the second opening 74, the movement of the second valve body 62B can be stabilized. Therefore, forced opening of the second valve unit 60B can be performed stably.

[0091] The cover 70 has a third opening 75 formed at a position facing at least a part of the third outer surface 632C of the third valve unit 60C. The third opening 75 penetrates the cover 70 along the Y-axis and communicates the inside and the outside of the valve unit housing portion 71. That is, a part of the third outer surface 632C of the third valve unit 60C is exposed to the outside by the third opening 75 provided in the cover 70. By exposing the third outer surface 632C of the third flexible film 63C to the outside of the cover 70 through the third opening 75 in this way, the third flexible film 63C can be pressed from the outside of the cover 70 in the -Y direction. Therefore, the third valve unit 60C can be forcibly opened from the outside of the cover 70.

[0092] Also, as described above, at least a part of the third outer surface 632C of the third valve unit 60C does not overlap with the second valve unit 60B when viewed in the -Y direction. Also, at least a part of the third outer surface 632C does not overlap with the fourth valve unit 60D when viewed in the -Y direction. For this reason, the third opening 75 is provided at a position that does not overlap with the second valve unit 60B and the fourth valve unit 60D of the third outer surface 632C when viewed in the -Y direction. That is, the third opening 75 is provided between the second valve unit 60B and the fourth valve unit 60D. Specifically, the third opening 75 is provided so as to penetrate in the direction along the Y-axis through the second partition wall 72B between the valve unit housing portion 71 that houses the second valve unit 60B and the valve unit housing portion 71 that houses the fourth valve unit 60D. The third opening 75 is formed so as to have the same opening area over the direction along the Y-axis. Also, the dimension of the second partition wall 72B in the direction along the Y-axis, that is, the length L3 of the third opening 75 along the Y-axis, is larger than the maximum width W1 of the valve unit 60 along the Y-axis.

[0093] Here, the distance L3 from one end to the other end of the third opening 75 is provided with substantially the same dimension as the distance L2 from one end to the other end of the second opening 74. For this reason, the distance L1 of the first opening 73 is shorter than the distance L3 of the third opening 75. That is, it is configured to satisfy L1 < L3.

[0094] Also, similar to the first opening 73 described above, the third opening 75 preferably overlaps at least a part of the third valve body 62C when viewed in the -Y direction. Also, the third opening 75 preferably overlaps at least a part of the third pressure receiving plate 66C when viewed in the -Y direction. By providing the third opening 75 at a position that overlaps with the third valve body 62C or a position that overlaps with the third pressure receiving plate 66C when viewed in the -Y direction in this way, when the third flexible film 63C is pressed from the outside of the cover 70 through the third opening 75, the movement of the third valve body 62C can be stabilized. Therefore, forced valve opening of the third valve unit 60C can be stably performed.

[0095] The cover 70 has a fourth opening 76 formed at a position facing at least a part of the fourth outer surface 632D of the fourth valve unit 60D. The fourth opening 76 penetrates the cover 70 along the X-axis and communicates the inside and the outside of the valve unit housing portion 71. That is, a part of the fourth outer surface 632D of the fourth valve unit 60D is exposed to the outside by the fourth opening 76 provided in the cover 70. In this way, by exposing the fourth outer surface 632D of the fourth flexible film 63D to the outside of the cover 70, that is, to the outside of the valve unit housing portion 71, the fourth flexible film 63D can be pressed from the outside of the cover 70 in the +Y direction, which is the second direction. Therefore, the fourth valve unit 60D can be forcibly opened from the outside of the cover 70.

[0096] Also, the area of the fourth opening 76 is preferably larger than the area of the third opening 75. Here, the areas of the fourth opening 76 and the third opening 75 refer to the areas of the opening portions on the outer surface of the cover 70. The fourth outer surface 632D has a portion not covered by the third valve unit 60C when viewed in the +Y direction, and since the valve unit 60 is not arranged in the +X direction compared to the third valve unit 60C, the fourth opening 76 can be provided with an extended width Wd in the +X direction. For this reason, the area of the fourth opening 76 is the same as the area of the first opening 73. On the other hand, the third outer surface 632C overlaps both the second valve unit 60B and the fourth valve unit 60D when viewed in the -Y direction, and since the third opening 75 is provided in the second partition wall 72B, the width Wc of the third opening 75 along the X-axis is relatively small. In the present embodiment, the opening area of the third opening 75 is the same as the area of the second opening 74. For this reason, since the width Wd of the fourth opening 76 in the direction along the X-axis can be made larger than the width Wc of the third opening 75, the area of the fourth opening 76 can be made larger than the area of the third opening 75 provided in the second partition wall 72B.

[0097] In addition, it is preferable that the relationships of t1, W1, t2, and D1 between the above-described first valve unit 60A and second valve unit 60B are the same even when the first valve unit 60A and second valve unit 60B are replaced with a fourth valve unit 60D and a third valve unit 60C. That is, it is preferable that the first valve unit 60A is replaced with the fourth valve unit 60D, the second valve unit 60B is replaced with the third valve unit 60C, and t1, W1, t2, and D1 satisfy the above-described relationships between the fourth valve unit 60D and the third valve unit 60C.

[0098] In addition, similar to the above-described first opening 73, it is preferable that the fourth opening 76 overlaps at least a part of the fourth valve body 62D when viewed in the +Y direction. Further, it is preferable that the fourth opening 76 overlaps at least a part of the fourth pressure receiving plate 66D when viewed in the +Y direction. By providing the fourth opening 76 at a position overlapping the fourth valve body 62D or a position overlapping the fourth pressure receiving plate 66D when viewed in the +Y direction in this way, when the fourth flexible film 63D is pressed from the outside of the cover 70 through the fourth opening 76, the movement of the fourth valve body 62D can be stabilized. Therefore, forced valve opening of the fourth valve unit 60D can be performed stably.

[0099] Relay substrates 51 are fixed to the +X direction and -X direction surfaces of the flow path member 50, respectively. The relay substrate 51 is made of a rigid substrate and is provided independently for each liquid injection unit 20. That is, in the present embodiment, two relay substrates 51 are arranged side by side along the X axis and fixed to the +Y direction surface of the flow path member 50. Further, two relay substrates 51 are arranged side by side along the X axis and fixed to the -Y direction surface of the flow path member 50. Of course, the two relay substrates 51 provided on the +Y direction and -Y direction surfaces, respectively, may be a single common relay substrate 51 continuous along the X axis.

[0100] The wiring board 22 of each liquid injection unit 20 is electrically connected to each of such relay substrates 51. That is, the end portion of the wiring board 22 on the side opposite to the liquid injection unit 20 is led out to the outside from the side surface in the direction along the Y axis and is electrically connected to the +Z direction end portion of the relay substrate 51 fixed to the side surface of the flow path member 50 along the Y axis.

[0101] Also, on the -Z direction surface of the cover 70, a convex portion 77 protruding in the -Z direction is provided. The convex portions 77 are provided continuously along the X-axis. Connection substrates 78 are fixed to the respective +Y direction and -Y direction surfaces of the convex portion 77. The connection substrate 78 is made of a rigid substrate, and a total of two are provided, one for each of the +Y direction and -Y direction of the convex portion 77. Each of the connection substrates 78 is provided with two connectors 78a to which the respective two wiring members 52 are connected, and a connector 78b to which wiring from the outside (not shown) is connected. Various signals such as a printed signal from the outside are supplied via the connector 78b. Such a connection substrate 78 and the relay substrate 51 are electrically connected via the wiring member 52. The wiring member 52 is a sheet-like member having flexibility, and for example, so-called flexible wiring such as a COF substrate, FFC, or FPC is used. The wiring member 52 is provided independently for each relay substrate 51. That is, on the +Y direction surface of the cover 70, the wiring members 52 are arranged side by side along the X-axis. Also, on the -Y direction surface of the cover 70, the wiring members 52 are arranged side by side along the X-axis. Here, among the wiring members 52, the wiring member 52 arranged at a position overlapping the first valve unit 60A when viewed in the +Y direction is referred to as the first wiring member 52A. Also, the wiring member 52 arranged at a position overlapping the second valve unit 60B when viewed in the -Y direction is referred to as the second wiring member 52B. Similarly, the wiring member 52 arranged at a position overlapping the third valve unit 60C when viewed in the +Y direction is referred to as the third wiring member 52C, and the wiring member 52 arranged at a position overlapping the fourth valve unit 60D when viewed in the -Y direction is referred to as the fourth wiring member 52D. And the first wiring member 52A is provided on the opposite side of the first outer surface 632A of the first valve unit 60A in the cover 70 in the -Y direction. Also, the second wiring member 52B is provided on the opposite side of the second outer surface 632B of the second valve unit 60B in the cover 70 in the +Y direction. Similarly, the third wiring member 52C is provided on the opposite side of the third outer surface 632C of the third valve unit 60C in the cover 70 in the -Y direction, and the fourth wiring member 52D is provided on the opposite side of the fourth outer surface 632D of the fourth valve unit 60D in the cover 70 in the +Y direction.In this embodiment, the first wiring member 52A and the first outer surface 632A are arranged at positions overlapping when viewed in the +Y direction. Also, the second wiring member 52B and the second outer surface 632B are arranged at positions overlapping when viewed in the -Y direction. Further, the third wiring member 52C and the third outer surface 632C are arranged at positions overlapping when viewed in the +Y direction. Additionally, the fourth wiring member 52D and the fourth outer surface 632D are arranged at positions overlapping when viewed in the -Y direction. However, each wiring member 52 is arranged at a position that does not block the openings of the first opening 73, the second opening 74, the third opening 75, and the fourth opening 76.

[0102] In this way, by providing the wiring member 52 on the outside of the cover 70, that is, on the side surfaces in the +Y direction and the -Y direction, each valve unit 60 is arranged such that the outer surface 632 of the flexible film 63 faces the opposite side of the wiring member 52 on the Y-axis. That is, since the first wiring member 52A is located in the -Y direction with respect to the first valve unit 60A, the first valve unit 60A is arranged such that the first outer surface 632A of the first flexible film 63A faces the +Y direction opposite to the first wiring member 52A. In other words, the first wiring member 52A is provided on the side opposite to the first outer surface 632A with respect to the surface on the opposite side of the first outer surface 632A of the first valve unit 60A. The same applies to the second valve unit 60B, the third valve unit 60C, and the fourth valve unit 60D. By arranging the valve unit 60 such that the outer surface 632 of the flexible film 63 is on the opposite side to the wiring member 52 in this way, it is possible to suppress the wiring member 52 from inhibiting the deformation of the flexible film 63. Also, by providing the wiring member 52 on the outside of the cover 70, even when the outer surface 632 of the flexible film 63 of each valve unit 60 faces the center side in the +Y direction of the recording head 10, the flexible film 63 can be pressed from outside the cover 70 through the first opening 73, the second opening 74, the third opening 75, and the fourth opening 76 to forcibly open the valve unit 60.

[0103] Further, on the -Z-direction surface of the cover 70, a flow path opening 79 is provided to expose the supply path 641 of each valve unit 60. The end where the supply path 641 of the valve unit 60 opens is provided on a protruding portion that protrudes in the -Z direction, and the flow path opening 79 of the cover 70 is inserted with the protruding portion where the supply path 641 opens. Thereby, on the -Z-direction side of the recording head 10, the supply member 2 can be connected to the supply path 641.

[0104] Here, an example of a pressing mechanism for forcibly opening the valve unit 60 will be described with reference to FIG. 14. Note that FIG. 14 is a cross-sectional view taken along the line B - B' of the recording head 10 and the pressing mechanism 80. Further, FIG. 14 shows a state in which the valve is forcibly opened by the pressing mechanism 80.

[0105] As shown in FIG. 14, a pressing mechanism 80 is separately provided outside the cover 70 of the recording head 10. In the present embodiment, a total of two pressing mechanisms 80 are provided, one each in the +Y direction and the -Y direction of the recording head 10. Hereinafter, the pressing mechanism 80 disposed in the +Y direction of the recording head 10 will be described.

[0106] The pressing mechanism 80 is composed of, for example, a push solenoid, and moves a shaft 82 connected to a plunger 81 along the Y-axis with respect to a frame member 83 by on / off control from the control unit 8. The frame member 83 is fixed to, for example, the support 3 or the apparatus main body 7. The tip side of the shaft 82 is bifurcated, and each of the two tips of the shaft is disposed at a position facing the first outer surface 632A exposed at the first opening 73 and the third outer surface 632C exposed at the third opening 75 in the -Y axis direction. In the pressing mechanism 80, by moving the shaft 82 in the -Y direction with respect to the frame member 83, each tip of the shaft 82 is brought into contact with the first outer surface 632A and the third outer surface 632C exposed by the first opening 73 and the third opening 75, and the first flexible film 63A and the third flexible film 63C are pressed in the -Y direction by the shaft 82 and displaced. Thereby, the first valve unit 60A and the third valve unit 60C can be forcibly opened simultaneously.

[0107] Note that since the pressing mechanism 80 arranged in the -Y direction is the same as the pressing mechanism 80 arranged in the +Y direction, duplicate explanations are omitted. Also, the pressing mechanism 80 arranged in the -Y direction can also forcibly open the second valve unit 60B and the fourth valve unit 60D simultaneously.

[0108] In this embodiment, since one pressing mechanism 80 can forcibly open two valve units 60, compared with a configuration in which a pressing mechanism is provided for each of the valve units 60, the configuration can be simplified, the cost can be reduced, and miniaturization can be achieved. Of course, a pressing mechanism may be provided for each of the valve units 60.

[0109] Also, in one head unit 1, three recording heads 10 are arranged side by side along the X-axis. Therefore, if branched according to the number of valve units 60 for which the tip of the shaft 82 is to be forcibly opened, one pressing mechanism 80 can forcibly open the valve units 60 provided in two or more recording heads 10 simultaneously. That is, in this embodiment, up to six valve units 60 can be forcibly opened by one pressing mechanism 80.

[0110] Also, in this embodiment, the second opening 74 and the third opening 75 are provided in the first partition wall 72A and the second partition wall 72B, and have a shape such that the opening areas in the direction along the Y-axis are substantially the same. For this reason, the tip of the shaft 82 can be guided by the inner wall surfaces of the second opening 74 and the third opening 75 and move toward the second flexible film 63B and the third flexible film 63C, so that the forced opening by the tip of the shaft 82 can be surely performed.

[0111] Note that in the head unit 1 of the present embodiment, three rows of recording heads 10 arranged side by side along the X-axis are provided in two rows along the Y-axis. Therefore, the gap between two adjacent recording heads 10 in the direction along the Y-axis is relatively small. Accordingly, when pressing the flexible film 63 exposed toward the gap between the recording heads 10 adjacent to each other in the direction along the Y-axis, the shaft 82 of the pressing mechanism 80 may be led out in the +X direction or the -X direction of this gap.

[0112] Also, in the present embodiment, a push solenoid is used as the pressing mechanism 80, but it is not particularly limited thereto, and an eccentric cam and a drive motor for rotating the same or the like may be used, or a hydraulic pump or the like may be used.

[0113] Also, in the present embodiment, one pressing mechanism 80 simultaneously forcibly opens the two valve units 60 of one recording head 10, but it is not particularly limited thereto, and one pressing mechanism 80 may forcibly open the four valve units 60 of one recording head 10. For example, shafts 82 may be provided at both ends of the plunger 81, and when the plunger 81 moves in the -Y direction, one shaft 82 forcibly opens the two valve units 60, and when the plunger 81 moves in the +Y direction, the other shaft 82 forcibly opens the two valve units 60. Also, one pressing mechanism may forcibly open the four valve units 60 simultaneously by combining gears or the like.

[0114] Also, in the present embodiment, the pressing mechanism 80 is provided, but it is not particularly limited thereto, and an operator may forcibly open the valve using a finger, a pin, or the like. Since the first opening 73 and the fourth opening 76 have a larger area than the second opening 74 and the third opening 75, the first opening 73 and the fourth opening 76 are easy to pass a finger through, and it is easy to directly press the first flexible film 63A and the fourth flexible film 63D with a finger.

[0115] As described above, the recording head 10, which is the liquid ejection head of the present embodiment, includes a liquid ejection unit 20 that ejects ink as a liquid, a first valve unit 60A that adjusts the pressure of the ink supplied to the liquid ejection unit 20, and a cover 70 that constitutes a housing for housing the liquid ejection unit 20 and the first valve unit 60A. Further, the first valve unit 60A has a first flow path 64A that communicates with the liquid ejection unit 20, a first inner surface 631A that defines a part of the first flow path 64A, and a first outer surface 632A that is on the side opposite to the first inner surface 631A and is in contact with the atmosphere, and includes a first flexible film 63A that is displaceable in the -Y direction, which is the first direction from the first outer surface 632A toward the first inner surface 631A, and the +Y direction, which is the second direction opposite to the -Y direction. Further, the first valve unit 60A has a first valve body 62A that moves between an open position where the first flow path 64A is opened and a closed position where the first flow path 64A is closed by the displacement of the first flexible film 63A. The cover 70 has a first opening 73 formed at a position facing at least a part of the first outer surface 632A.

[0116] In this way, since the first outer surface 632A is exposed to the outside by the first opening 73 formed in the cover 70, the first flexible film 63A can be operated from the outside of the recording head 10. Therefore, it is not necessary to provide a pressing mechanism or the like for operating the first flexible film 63A inside the recording head 10, and the recording head 10 can be downsized and the structure can be simplified. Further, since the first flexible film 63A can be easily operated from the outside of the recording head 10 through the first opening 73, it is possible to cause forced displacement by an external force that does not depend on the pressure difference between the first inner surface 631A and the first outer surface 632A of the first flexible film 63A, and the first valve body 62A can be moved to the open position to perform forced valve opening.

[0117] Further, in the recording head 10 of the present embodiment, it is preferable that the first opening 73 overlaps at least a part of the first valve body 62A when viewed in the -Y direction, which is the first direction. According to this, when the first flexible film 63A is pressed in the -Y direction to perform forced valve opening, the movement of the valve body 62 in the -Y direction can be stabilized. Therefore, stable forced valve opening can be performed.

[0118] Further, in the recording head 10 of the present embodiment, the first valve unit 60A has a higher Young's modulus than the first flexible film 63A, is provided on the first inner surface 631A of the first flexible film 63A, and is a first pressure receiving plate 66A that contacts the tip of the first valve body 62A when the first valve body 62A is in the open position. It is preferable that the first opening 73 overlaps at least a part of the first pressure receiving plate 66A when viewed in the -Y direction, which is the first direction. According to this, when the first flexible film 63A is pressed in the -Y direction to forcibly open the valve, the first pressure receiving plate 66A can be pressed, and the movement of the first valve body 62A that moves by the first pressure receiving plate 66A can be stabilized. Therefore, stable forced valve opening can be performed.

[0119] Further, in the recording head 10 of the present embodiment, the gap t1 between the portion of the inner wall surface 71a of the cover 70 constituting the housing, which is a position different from the first opening 73 and faces the first outer surface 632A, and the first outer surface 632A is preferably smaller than the dimension W1 in the -Y direction, which is the first direction, of the first valve unit 60A. According to this, the recording head 10 can be miniaturized in the -Y direction. Note that it is more preferable that the gap t1 is smaller than 1 / 2 of the dimension W1 of the first valve unit 60A.

[0120] Further, in the recording head 10 of the present embodiment, the gap t1 between the portion of the inner wall surface 71a of the cover 70 constituting the housing, which is a position different from the first opening 73 and faces the first outer surface 632A, and the first outer surface 632A is preferably smaller than the maximum displacement amount D1 in the -Y direction, which is the first direction, of the first flexible film 63A. According to this, the recording head 10 can be miniaturized in the -Y direction.

[0121] Further, in the recording head 10 of the present embodiment, a second valve unit 60B for adjusting the pressure of ink, which is a liquid supplied to the liquid ejection unit 20, is further provided inside a cover 70 that constitutes the housing. The second valve unit 60B has a second flow path 64B communicating with the liquid ejection unit 20, a second inner surface 631B defining a part of the second flow path 64B, and a second outer surface 632B that is on the side opposite to the second inner surface 631B and is in contact with the atmosphere. The second valve unit 60B includes a second flexible film 63B that is displaceable in the +Y direction, which is the second direction from the second outer surface 632B toward the second inner surface 631B, and the -Y direction, which is the first direction. The second valve unit 60B has a second valve body 62B that moves between an open position where the second flow path 64B is opened and a closed position where the second flow path 64B is closed by the displacement of the second flexible film 63B. The second valve unit 60B is displaced in the +Y direction with respect to the first valve unit 60A and in the +Z direction or +Y direction, which is the third direction orthogonal to the -Y direction, so as to overlap a part of the first valve unit 60A when viewed in the -Y direction. At least a part of the first outer surface 632A does not overlap the second valve unit 60B when viewed in the -Y direction. At least a part of the second outer surface 632B does not overlap the first valve unit 60A when viewed in the +Y direction. The cover 70 that constitutes the housing preferably has a second opening 74 formed at a position facing at least a part of the second outer surface 632B.

[0122] In this way, even if a plurality of valve units 60 are provided in the recording head 10 and the outer surfaces 632 of the plurality of valve units 60 are arranged to face each other, at least a part of the outer surface 632 of the valve unit 60 is arranged not to overlap with other valve units 60. Therefore, forced valve opening can be performed through the first opening 73 and the second opening 74. Note that the outer surfaces 632 of the plurality of valve units 60 may be arranged facing outward so as not to face each other.

[0123] Further, in the recording head 10 of the present embodiment, the third direction is preferably the +X direction orthogonal to the +Z direction, which is the ejection direction in which the liquid ejection unit 20 ejects ink, which is a liquid. According to this, it is possible to suppress the recording head 10 from increasing in size in the +Z direction and to reduce the size in the +Z direction.

[0124] Further, in the recording head 10 of the present embodiment, it is preferable that the first valve unit 60A and the second valve unit 60B are arranged at the same position in the +Z direction which is the injection direction. According to this, the recording head 10 can be downsized in the +Z direction.

[0125] Further, in the recording head 10 of the present embodiment, it is preferable that the distance L1 from the opening at one end to the opening at the other end of the first opening 73 is shorter than the distance L2 from the opening at one end to the opening at the other end of the second opening 74. By forming the cover 70 into a shape along the arrangement of the plurality of valve units 60, the distance L1 of the first opening 73 can be made shorter than the distance L2 of the second opening 74. For this reason, the cover 70 can be downsized.

[0126] Further, in the recording head 10 of the present embodiment, it is preferable that the area of the first opening 73 is larger than the area of the second opening 74. By making the area of the first opening 73 larger than the area of the second opening 74, it is easy to press the first flexible film 63A through the first opening 73.

[0127] Further, in the recording head 10 of the present embodiment, the gap t1 between the portion of the inner wall surface 71a of the cover 70 constituting the housing, which is at a position different from the first opening 73 and faces the first outer surface 632A, and the first outer surface 632A is preferably narrower than the interval t2 between the first valve unit 60A and the second valve unit 60B in the -Y direction which is the first direction. According to this, the recording head 10 can be downsized in the -Y direction.

[0128] Further, in the recording head 10 of the present embodiment, it is preferable that the first outer surface 632A and the second valve unit 60B partially overlap when viewed in the -Y direction which is the first direction. According to this, the recording head 10 can be downsized in the +X direction.

[0129] Further, in the recording head 10 of the present embodiment, a first wiring member 52A is provided on a surface opposite to the first outer surface 632A of the first valve unit 60A, on a surface opposite to the first outer surface 632A, and is connected to the liquid injection unit 20; and a second wiring member 52B is provided on a surface opposite to the second outer surface 632B of the second valve unit 60B, on a surface opposite to the first outer surface 632B, and is connected to the liquid injection unit 20. It is preferable to include these. In an arrangement where the wiring member 52 is routed outside the region where the valve unit 60 is provided, it is necessary to direct the flexible film 63 of the valve unit 60 toward the inside of the recording head 10. Even in a configuration where the flexible film 63 is directed toward the inside of the recording head 10 in this way, the valve unit 60 can be forced to open by operating the flexible film 63 from the outside through the first opening 73 and the second opening 74.

[0130] Further, the recording head 10 of the present embodiment further includes a third valve unit 60C disposed inside a cover 70 that constitutes a housing and that adjusts the pressure of ink, which is a liquid supplied to the liquid injection unit 20. The third valve unit 60C is disposed in the +Z direction or the +X direction, which is the third direction, with respect to the first valve unit 60A, and is disposed so as to overlap a part of the second valve unit 60B when viewed in the +Y direction, which is the second direction. It is preferable that the second opening 74 is provided between the first valve unit 60A and the third valve unit 60C. Even when the first valve unit 60A, the second valve unit 60B, and the third valve unit 60C are arranged as described above, the second opening 74 can be provided between the first valve unit 60A and the third valve unit 60C. Then, the second flexible film 63B can be operated from the outside of the housing through the second opening 74 to force the second valve unit 60B to open.

[0131] Further, in the recording head 10 of the present embodiment, the cover 70 that constitutes the housing has a first partition wall 72A that is a partition wall partitioning between the first valve unit 60A and the third valve unit 60C, and it is preferable that the second opening 74 is formed so as to penetrate the first partition wall 72A in the -Y direction, which is the first direction. A shaft 82 for operating the second flexible film 63B can be guided by the inner wall surface of the second opening 74, and the second valve unit 60B can be surely forced to open.

[0132] Further, in the recording head 10 of the present embodiment, it is preferable that the second flexible film 63B overlaps both the first valve unit 60A and the third valve unit 60C when viewed in the +Y direction which is the second direction. According to this, miniaturization of the recording head 10 in the +X direction can be achieved.

[0133] Moreover, an inkjet recording apparatus I which is an example of the liquid ejection apparatus of the present embodiment includes a recording head 10 which is an example of the liquid ejection head described above, and a liquid storage unit 4 which stores ink for supplying the ink which is a liquid to the recording head 10. As described above, it is not necessary to provide a pressing mechanism or the like for operating the first flexible film 63A inside the recording head 10, and miniaturization and simplification of the structure of the recording head 10 can be achieved. Therefore, miniaturization and simplification of the structure of the inkjet recording apparatus I including the recording head 10 can be achieved.

[0134] (Other embodiments) As described above, one embodiment of the present invention has been described, but the basic configuration of the present invention is not limited to the above-described one.

[0135] For example, in the above-described Embodiment 1, the relay substrate 51 and the wiring member 52 are illustrated as being exposed on the side surfaces of the flow path member 50 and the cover 70, but are not particularly limited thereto, and wiring covers for covering the relay substrate 51 and the wiring member 52 may be provided on both sides of the cover 70 in the +Y direction and the -Y direction, respectively. Further, when a wiring cover is provided, by providing communication holes in the wiring cover that communicate with the first opening 73, the second opening 74, the third opening 75, and the fourth opening 76, the flexible film 63 of each valve unit 60 can be exposed to the outside, and the flexible film 63 can be operated from the outside of the wiring cover to forcibly open the valve.

[0136] Moreover, the valve unit 60 may be provided with a flow path or the like for recovering the ink that has not been ejected from the nozzles 21 among the ink supplied to the liquid ejection unit 20. That is, the ink may be circulated between the liquid storage unit 4 and the liquid ejection unit 20.

[0137] Further, the valve unit 60 may be provided with a filter for removing foreign matters such as dust and air bubbles contained in the ink flowing through the valve unit flow path 64.

[0138] Also, in the above-described Embodiment 1, the third direction is set as the +X direction, but it is not particularly limited thereto. Since the third direction may be any direction orthogonal to the -Y direction which is the first direction, for example, the third direction may be set as the +Z direction. That is, the second valve unit 60B may be arranged at a position shifted in the +Y direction and the +Z direction with respect to the first valve unit 60A so that a part thereof overlaps the first valve unit 60A when viewed in the -Y direction. Even in this case, since the first flexible film 63A can be pressed in the -Y direction which is the first direction through the first opening 73, the first valve unit 60A can be forcibly opened. The same applies to the third valve unit 60C and the fourth valve unit 60D.

[0139] Furthermore, the present invention is directed to liquid ejection heads in general, and can be applied to, for example, recording heads such as various inkjet recording heads used in image recording apparatuses such as printers, color material ejection heads used in the manufacture of color filters such as liquid crystal displays, electrode material ejection heads used in the formation of electrodes such as organic EL displays and FED (field emission displays), and biological organic matter ejection heads used in the manufacture of biochips. Also, although an inkjet recording apparatus has been described as an example of the liquid ejection apparatus, it can also be used in liquid ejection apparatuses using the other liquid ejection heads described above.

Description of Reference Numerals

[0140] I... Inkjet recording apparatus (liquid ejection apparatus), 1... Head unit, 2... Supply member, 3... Support, 3a... Support hole, 3b... Screw hole, 4... Liquid storage section, 4a... Supply pipe, 4b... Pump, 5... First conveying means, 6... Second conveying means, 7... Apparatus main body, 8... Control unit, 10... Inkjet recording head (liquid ejection head), 11... Fixing hole, 12... Screw, 20... Liquid ejection section, 21... Nozzle, 22... Wiring board, 30... Holder, 31... Accommodation section, 33... Recess, 34... Wiring insertion hole, 35... Flange section, 40... Fixing plate, 41... Exposure opening, 50... Flow path member, 51... Relay board, 52... Wiring member, 52A... First wiring member, 52B... Second wiring member, 52C... Third wiring member, 52D... Fourth wiring member, 60... Valve unit, 60A... First valve unit, 60B... Second valve unit, 60C... Third valve unit, 60D... Fourth valve unit, 61... Valve unit main body, 62... Valve body, 62A... First valve body, 62B... Second valve body, 62C... Third valve body, 62D... Fourth valve body, 63... Flexible film, 63A... First flexible film, 63B... Second flexible film, 63C... Third flexible film, 63D... Fourth flexible film, 64... Valve unit flow path, 64A... First flow path, 64B... Second flow path, 64C... Third flow path, 64D... Fourth flow path, 65... Flow path partition wall, 66... Pressure receiving plate, 66A... First pressure receiving plate, 66B... Second pressure receiving plate, 66C... Third pressure receiving plate, 66D... Fourth pressure receiving plate, 67... Coil spring, 70... Cover, 71... Valve unit accommodation section, 71a... Inner wall surface, 72A... First partition wall, 72B... Second partition wall, 73... First opening, 74... Second opening, 75... Third opening, 76... Fourth opening, 77... Protrusion, 78... Connection board, 79... Flow path opening, 80... Pressing mechanism, 81... Plunger, 82... Shaft, 83... Frame member, 501... First conveying roller, 502... First driven roller, 503... First drive motor, 601... Conveying belt, 602... Second drive motor, 603... Second conveying roller, 604... Second driven roller, 605... Tension roller, 606... Biasing member, 621... Base end portion, 622... Shaft portion, 623... Elastic member, 631... Inner surface, 631A... First inner surface, 631B... Second inner surface, 631C... Third inner surface, 631D... Fourth inner surface, 632... Outer surface, 632A... First outer surface, 632B... Second outer surface, 632C... Third outer surface, 632D... Fourth outer surface, 641... Supply path, 642... Liquid supply chamber, 643... Discharge path, 644... Pressure chamber, 651... Communication hole, 652... Valve seat, LC... Center line,P1... Part 1, P2... Part 2, P3... Part 3, R... Rectangle, S... Medium,

Claims

1. a liquid injection unit that injects a liquid; a first valve unit that adjusts the pressure of the liquid supplied to the liquid injection unit; a housing that houses the liquid injection unit and the first valve unit; comprising the first valve unit has a first flow path communicating with the liquid injection unit, a first inner surface defining a part of the first flow path, and a first outer surface that is a surface opposite to the first inner surface and is in contact with the atmosphere, and a first flexible film displaceable in a first direction from the first outer surface toward the first inner surface and a second direction opposite to the first direction; a first valve body that moves between an open position where the first flow path is opened and a closed position where the first flow path is closed by the displacement of the first flexible film; having the housing has a first opening formed at a position facing at least a part of the first outer surface; A liquid injection head characterized by the above.

2. The first opening overlaps at least a part of the first valve body when viewed in the first direction. The liquid injection head according to claim 1, characterized in that.

3. The first valve unit has a pressure receiving plate that has a higher Young's modulus than the first flexible film, is provided on the first inner surface of the first flexible film, and contacts the tip of the first valve body when the first valve body is in the open position. The first opening overlaps at least a part of the pressure receiving plate when viewed in the first direction. The liquid injection head according to claim 1 or 2, characterized in that.

4. The gap between the portion of the inner wall surface of the housing that is different from the first opening and faces the first outer surface and the first outer surface is smaller than the dimension of the first valve unit in the first direction. The liquid injection head according to any one of claims 1 to 3, characterized in that.

5. The gap between the portion of the inner wall surface of the housing that is different from the first opening and faces the first outer surface and the first outer surface is smaller than the maximum displacement amount of the first flexible film in the first direction. The liquid injection head according to any one of claims 1 to 4, characterized in that.

6. further comprising a second valve unit disposed in the housing and adjusting the pressure of the liquid supplied to the liquid injection unit, the second valve unit has a second flow path communicating with the liquid injection unit, a second inner surface defining a part of the second flow path, and a second outer surface that is a surface opposite to the second inner surface and is in contact with the atmosphere, and a second flexible film displaceable in the second direction from the second outer surface toward the second inner surface and the first direction; A second valve body that moves between an open position that opens the second flow path and a closed position that closes the second flow path by the displacement of the second flexible film. The second valve unit is displaced in the second direction and in a third direction orthogonal to the first direction with respect to the first valve unit so as to overlap a part of the first valve unit when viewed in the first direction. At least a part of the first outer surface does not overlap the second valve unit when viewed in the first direction. At least a part of the second outer surface does not overlap the first valve unit when viewed in the second direction. The housing has a second opening formed at a position facing at least a part of the second outer surface. The liquid ejection head according to any one of claims 1 to 5, characterized in that.

7. The third direction is a direction orthogonal to the ejection direction in which the liquid ejection unit ejects liquid. The liquid ejection head according to claim 6, characterized in that.

8. The first valve unit and the second valve unit are arranged at the same position in the ejection direction. The liquid ejection head according to claim 7, characterized in that.

9. The distance from the opening at one end to the opening at the other end of the first opening is shorter than the distance from the opening at one end to the opening at the other end of the second opening. The liquid ejection head according to any one of claims 6 to 8, characterized in that.

10. The area of the first opening is larger than the area of the second opening. The liquid ejection head according to any one of claims 6 to 9, characterized in that.

11. The gap between the portion of the inner wall surface of the housing that is different from the first opening and faces the first outer surface and the first outer surface is narrower than the interval between the first valve unit and the second valve unit in the first direction. The liquid ejection head according to any one of claims 6 to 10, characterized in that.

12. A part of the first outer surface and the second valve unit overlap when viewed in the first direction. The liquid ejection head according to any one of claims 6 to 11, characterized in that.

13. A first wiring member provided on the side opposite to the first outer surface with respect to the surface of the first valve unit opposite to the first outer surface and connected to the liquid ejection unit. A second wiring member provided on the side opposite to the second outer surface with respect to the surface of the second valve unit opposite to the second outer surface and connected to the liquid ejection unit. Comprising. The liquid ejection head according to any one of claims 6 to 12, characterized in that.

14. Further comprising a third valve unit disposed within the housing for adjusting the pressure of the liquid supplied to the liquid injection unit, The third valve unit is disposed in the third direction with respect to the first valve unit and is disposed so as to overlap a part of the second valve unit when viewed in the second direction, The second opening is provided between the first valve unit and the third valve unit, The liquid injection head according to any one of claims 6 to 13, characterized in that.

15. The housing has a partition wall partitioning between the first valve unit and the third valve unit, The second opening is formed so as to penetrate the partition wall in the first direction, The liquid injection head according to claim 14, characterized in that.

16. The second flexible film overlaps both the first valve unit and the third valve unit when viewed in the second direction, The liquid injection head according to claim 14 or 15, characterized in that.

17. A liquid injection head according to any one of claims 1 to 16, A liquid storage unit for storing a liquid for supplying the liquid to the liquid injection head, A liquid injection device comprising.

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