Liquid ejection head

Abstract

To enable observation to be performed on presence or absence of a liquid pool in a compliance space without removing a fixture plate.SOLUTION: A liquid ejection head comprises: a plurality of head chips including a nozzle plate with a plurality of nozzles for ejecting liquid; and a fixture plate to which the plurality of head chips is fixed and which has a plurality of openings for exposing the nozzle plate outward. Therein: each of the plurality of head chips includes a compliance substrate for damping pressure fluctuations within a flow path communicating with the plurality of nozzles; a compliance space for allowing the compliance substrate to deform is provided between the fixture plate and the compliance substrate; and the fixture plate is capable of transmitting visible light, infrared light or X-rays in at least a portion of a region overlapping the compliance space when viewed in a thickness direction of the fixture plate.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a liquid jet head. [Background technology]

[0002] A liquid jet head, such as an inkjet head, may use a fixing plate to fix multiple head chips that eject liquid. This fixing plate is provided with multiple openings that expose the nozzle plate of each head chip to the outside.

[0003] In Patent Document 1, multiple head chips are fixed to a metal fixing plate. Here, the head chips have a compliance substrate for absorbing pressure fluctuations of the liquid inside the head chips, and a compliance space, which is a space that allows deformation of the compliance substrate, is provided between the compliance substrate and the fixing plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-122217 Summary of the Invention [Problem to be solved by the invention]

[0005] The compliance space is open to the atmosphere. Therefore, the intrusion of liquid into the compliance space may cause abnormalities in the function of the compliance substrate. In the head described in Patent Document 1, the fixing plate is made of metal, so it is not possible to non-destructively observe the intrusion of liquid into the compliance space, and therefore it is not possible to detect such abnormalities. [Means for solving the problem]

[0006] In order to solve the above problems, a liquid ejection head according to a preferred embodiment of the present disclosure comprises a plurality of head chips including a nozzle plate having a plurality of nozzles for ejecting liquid, and a fixed plate to which the plurality of head chips are fixed and having a plurality of openings for exposing the nozzle plate to the outside, wherein each of the plurality of head chips includes a compliance substrate for absorbing pressure fluctuations in a flow path communicating with the plurality of nozzles, and a compliance space is provided between the fixed plate and the compliance substrate, which is a space for allowing deformation of the compliance substrate, and the fixed plate is capable of transmitting visible light, infrared light, or X-rays in at least a portion of the area overlapping the compliance space when viewed in the thickness direction of the fixed plate. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a liquid jet apparatus including a liquid jet head according to a first embodiment. [Figure 2] FIG. 1 is a perspective view of a head module having a liquid jet head according to a first embodiment. [Figure 3] FIG. 2 is an exploded perspective view of the liquid jet head. [Figure 4] FIG. 2 is a schematic diagram illustrating an example of the configuration of a head chip. [Figure 5] FIG. 2 is a cross-sectional view showing an example of the configuration of a head chip. [Figure 6] 10 is a plan view showing the positional relationship between the nozzle plate, the openings of the fixed plate, and the compliance space of the compliance substrate. FIG. [Figure 7] 1 is a cross-sectional view of a liquid jet head according to a first embodiment. [Figure 8] FIG. 4 is a cross-sectional view of a liquid jet head according to a second embodiment. [Figure 9] FIG. 10 is a cross-sectional view of a liquid jet head according to a third embodiment. [Figure 10] FIG. 10 is a plan view illustrating a fixing plate in the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. Note that the dimensions and scale of each part in the drawings may differ from the actual dimensions and are shown schematically to facilitate understanding. Furthermore, the scope of the present disclosure is not limited to these embodiments unless otherwise specified in the following description to the effect that the present disclosure is limited.

[0009] For convenience, the following description will use the mutually intersecting X-axis, Y-axis, and Z-axis as appropriate. In the following, one direction along the X-axis is the X1 direction, and the direction opposite the X1 direction is the X2 direction. Similarly, the opposite directions along the Y-axis are the Y1 direction and the Y2 direction. Furthermore, the opposite directions along the Z-axis are the Z1 direction and the Z2 direction. The Z2 direction is an example of a "first direction," and the Z1 direction is an example of a "second direction."

[0010] Typically, the Z axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. However, the Z axis does not have to be a vertical axis. Furthermore, the X axis, Y axis, and Z axis are typically perpendicular to each other, but are not limited to this. For example, they may intersect at an angle between 80° and 100°.

[0011] 1. First embodiment 1-1. Schematic configuration of a liquid ejection device equipped with a liquid ejection head FIG. 1 is a schematic diagram showing an example of the configuration of a liquid ejection apparatus 100 according to a first embodiment. The liquid ejection apparatus 100 is an inkjet printing apparatus that ejects ink, which is an example of a "liquid," as droplets onto a medium M. The medium M is typically printing paper. However, the medium M is not limited to printing paper, and may be a printing target made of any material, such as a resin film or fabric.

[0012] 1, the liquid ejecting device 100 includes a liquid container 10, a control unit 20, a transport mechanism 30, a movement mechanism 40, a head module 50, and a circulation mechanism 60. Each of these will be briefly described below with reference to FIG.

[0013] The liquid container 10 stores ink. Specific examples of the liquid container 10 include a cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink pack made of flexible film, and an ink tank that can be refilled with ink. The type of ink stored in the liquid container 10 is not particularly limited and can be any type.

[0014] The control unit 20 includes a processing circuit such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array) and a storage circuit such as a semiconductor memory, and controls the operation of each element of the liquid ejection device 100.

[0015] The transport mechanism 30 transports the medium M in a transport direction DM, which is the Y1 direction, under the control of the control unit 20. The movement mechanism 40 reciprocates the head module 50 in the X1 and X2 directions under the control of the control unit 20. In the example shown in FIG. 1, the movement mechanism 40 has a substantially box-shaped transport body 41 called a carriage that houses the head module 50, and a transport belt 42 to which the transport body 41 is fixed. Note that in addition to the head module 50, the transport body 41 may also be equipped with the aforementioned liquid container 10.

[0016] Under the control of the control unit 20, the head module 50 ejects ink supplied from the liquid container 10 via the circulation mechanism 60 from each of the multiple nozzles onto the medium M in the Z2 direction. This ejection is performed in parallel with the transport of the medium M by the transport mechanism 30 and the reciprocating movement of the head module 50 by the movement mechanism 40, thereby forming an ink image on the surface of the medium M. The head module 50 has multiple liquid ejection heads 1. Details of the liquid ejection heads 1 will be described later with reference to FIGS. 2 to 7.

[0017] In the example shown in FIG. 1 , the liquid container 10 is connected to the head module 50 via a circulation mechanism 60. The circulation mechanism 60 is a mechanism that supplies ink to the head module 50 and recovers ink discharged from the head module 50 for resupply to the head module 50. The operation of the circulation mechanism 60 can suppress an increase in the viscosity of the ink and reduce the accumulation of air bubbles in the ink. Note that the circulation mechanism 60 is provided as needed and may be omitted. In other words, the liquid ejecting device 100 does not need to have a configuration that circulates ink within the liquid ejecting head 1.

[0018] 1-2. Liquid jet head 2 is a perspective view of a head module 50 having the liquid jet head 1 according to the first embodiment. As shown in FIG.

[0019] The support body 51 is a plate-like member that supports a plurality of liquid jet heads 1. A plurality of mounting holes 51a are provided in the support body 51. Each liquid jet head 1 is inserted into the mounting hole 51a and fixed to the support body 51 by screws or the like. The plurality of liquid jet heads 1 are arranged in a matrix along the X-axis and Y-axis.

[0020] The number and arrangement of the liquid jet heads 1 included in the head module 50 are not limited to the example shown in Fig. 2, and are arbitrary. Furthermore, the shape of the support body 51 is also not limited to the example shown in Fig. 2, and is arbitrary.

[0021] Fig. 3 is an exploded perspective view of the liquid jet head 1. As shown in Fig. 3, the liquid jet head 1 includes a flow path structure 11, a wiring board 12, a holder 13, four head chips HC, a fixing plate 14, a reinforcing plate 15, and a cover 16. These are arranged in the Z2 direction in the following order: cover 16, wiring board 12, flow path structure 11, holder 13, four head chips HC, reinforcing plate 15, and fixing plate 14. Below, an overview of each part of the liquid jet head 1 will be sequentially described with reference to Fig. 4.

[0022] The flow path structure 11 is a structure in which flow paths are provided inside for supplying ink from the circulation mechanism 60 to the four head chips HC. The flow path structure 11 has a flow path member 11a and four connecting pipes 11b, 11c, 11d, and 11e.

[0023] Although not shown in FIG. 3, the flow path member 11a is provided with supply flow paths for supplying ink to the four head chips HC and discharge flow paths for discharging ink from the four head chips HC.

[0024] The flow path member 11a has a plurality of substrates Su1 to Su5, which are stacked in the Z2 direction in this order. Each of the substrates Su1 to Su5 is made of a resin material such as Zylon, PPS (polyphenylene sulfide), or PP (polypropylene), and is formed by injection molding. "Zylon" is a registered trademark. The plurality of substrates Su1 to Su5 are bonded to one another with an adhesive such as an epoxy adhesive. The number or thickness of the substrates constituting the flow path member 11a is not limited to the example shown in FIG. 3 and can be any number.

[0025] Each of the connecting pipes 11b, 11c, 11d, and 11e is a pipe body protruding from the surface of the flow path member 11a facing the Z1 direction. Each of the connecting pipes 11b and 11c is connected to the aforementioned supply flow path. Each of the connecting pipes 11d and 11e is connected to the aforementioned discharge flow path.

[0026] The wiring board 12 is a mounting component for electrically connecting the liquid jet head 1 to the control unit 20. The wiring board 12 is configured, for example, as a flexible wiring board or a rigid wiring board. The wiring board 12 is disposed on the flow path structure 11, and the surface of the wiring board 12 facing the Z2 direction faces the flow path structure 11. On the other hand, a connector 12a is provided on the surface of the wiring board 12 facing the Z1 direction. The connector 12a is a connecting component for electrically connecting the liquid jet head 1 and the control unit 20. Although not shown, wiring connected to the four head chips HC is also connected to the wiring board 12. The wiring is configured, for example, as a combination of a flexible wiring board and a rigid wiring board. Note that the wiring may be configured integrally with the wiring board 12.

[0027] The holder 13 is a structure that houses and supports four head chips HC. The holder 13 is made of, for example, a resin material or a metal material. The holder 13 is provided with a plurality of holder flow paths 13a, a plurality of wiring holes 13b, and a plurality of recesses 13c. Each of the plurality of holder flow paths 13a is a hole for allowing ink to flow between the head chip HC and the flow path structure 11. The holder flow paths 13a are provided corresponding to the inlet ports Ra_in and Rb_in and the outlet ports Ra_out and Rb_out, which will be described later. Each of the plurality of wiring holes 13b is a hole through which wiring (not shown) that connects the head chip HC and the wiring substrate 12 is passed. Each of the plurality of recesses 13c is open toward the Z2 direction and is a space in which the head chip HC is placed.

[0028] Each head chip HC ejects ink. Each head chip HC is provided with inlets Ra_in, Rb_in and outlets Ra_out, Rb_out. Each of the inlets Ra_in, Rb_in is an opening for introducing ink. Each of the outlets Ra_out, Rb_out is an opening for discharging ink. Each of the inlets Ra_in, Rb_in and outlets Ra_out, Rb_out is liquid-tightly connected to the corresponding holder flow path 13a by being bonded to the head chip HC and the holder 13 with an adhesive. The configuration of the head chip HC will be described in detail below with reference to Figures 4 and 5.

[0029] The fixing plate 14 is a plate member for fixing the four head chips HC to the holder 13, and the four head chips HC are fixed to the fixing plate 14. Specifically, the fixing plate 14 is arranged so that the four head chips HC are sandwiched between the fixing plate 14 and the holder 13, and is fixed to the holder 13 with an adhesive. As will be described later, the fixing plate 14 is made of a material that is transparent to visible light, infrared light, or X-rays. The fixing plate 14 has a plurality of openings 14a for exposing nozzle plates 18c (described later) of the four head chips HC to the outside. In the example shown in FIG. 3, the plurality of openings 14a are provided individually for each head chip HC.

[0030] The reinforcing plate 15 is a plate-like member that is disposed between the holder 13 and the fixed plate 14 and reinforces the fixed plate 14. The reinforcing plate 15 is disposed on top of the fixed plate 14 and fixed to the fixed plate 14 with an adhesive. The reinforcing plate 15 is provided with a plurality of openings 15a in which four head chips HC are disposed. The reinforcing plate 15 is made of, for example, a metal material. The reinforcing plate 15 is provided as needed and may be omitted.

[0031] The cover 16 is a box-shaped member that houses the flow path member 11a and the wiring board 12 of the flow path structure 11. The cover 16 is made of, for example, a resin material. The cover 16 is provided with four through holes 16a and an opening 16b. The four through holes 16a correspond to the connecting pipes 11b, 11c, 11d, and 11e of the flow path structure 11, and one of the corresponding connecting pipes 11b, 11c, 11d, and 11e is inserted into each through hole 16a. A connector 12a is passed through the opening 16b from inside the cover 16 to the outside.

[0032] 1-3.Head chip FIG. 4 is a schematic diagram showing an example of the configuration of the head chip HC. FIG. 4 schematically shows the internal structure of the head chip HC as viewed in the Z2 direction. As shown in FIG. 4, the head chip HC is provided with a plurality of nozzles N that eject ink. The plurality of nozzles N are divided into nozzle rows La and nozzle rows Lb. Each of the nozzle rows La and nozzle rows Lb is a collection of a plurality of nozzles N arranged along the Y axis. The nozzle rows La and nozzle rows Lb are arranged at intervals from each other in the X axis direction.

[0033] The head chip HC has a liquid ejecting section Qa including a nozzle row La, and a liquid ejecting section Qb including a nozzle row Lb.

[0034] The liquid ejection unit Qa has a liquid storage chamber Ra, multiple pressure chambers Ca, and multiple drive elements Ea. The liquid storage chamber Ra is a common liquid chamber that is continuous across the multiple nozzles N of the nozzle array La. Each pressure chamber Ca and drive element Ea is provided for each nozzle N of the nozzle array La. The pressure chamber Ca is a space that communicates with the nozzle N. Each of the multiple pressure chambers Ca is filled with ink supplied from the liquid storage chamber Ra. The drive element Ea varies the pressure of the ink in the pressure chamber Ca. The drive element Ea is, for example, a piezoelectric element that changes the volume of the pressure chamber Ca by deforming the wall surface of the pressure chamber Ca, or a heating element that heats the ink in the pressure chamber Ca to generate bubbles in the pressure chamber Ca. When the drive element Ea varies the pressure of the ink in the pressure chamber Ca, the ink in the pressure chamber Ca is ejected from the nozzle N.

[0035] In this specification, "communication" includes not only a situation in which two target spaces are directly connected to form one space, but also a situation in which two target spaces are connected via another space to form one space.

[0036] Like the liquid ejection unit Qa, the liquid ejection unit Qb has a liquid storage chamber Rb, multiple pressure chambers Cb, and multiple drive elements Eb. The liquid storage chamber Rb is a common liquid chamber that is continuous across the multiple nozzles N of the nozzle row Lb. Each of the pressure chambers Cb and drive elements Eb is provided for each nozzle N of the nozzle row Lb. Each of the multiple pressure chambers Cb is filled with ink supplied from the liquid storage chamber Rb. The drive elements Eb are, for example, the aforementioned piezoelectric elements or heat generating elements. The drive elements Eb vary the pressure of the ink in the pressure chambers Cb, causing the ink in the pressure chambers Cb to be ejected from the nozzles N.

[0037] 4, the head chip HC is provided with an inlet Ra_in, an outlet Ra_out, an inlet Rb_in, and an outlet Rb_out. The inlet Ra_in and the outlet Ra_out each communicate with the liquid storage chamber Ra. The inlet Rb_in and the outlet Rb_out each communicate with the liquid storage chamber Rb.

[0038] In the head chip HC described above, ink introduced into the liquid storage chamber Ra through the inlet Ra_in is used as appropriate for ejection from each nozzle N of the nozzle array La. Furthermore, ink that is not ejected from each nozzle N of the nozzle array La and remains in the liquid storage chamber Ra is discharged through the outlet Ra_out. Similarly, ink introduced into the liquid storage chamber Rb through the inlet Rb_in is used as appropriate for ejection from each nozzle N of the nozzle array Lb. Furthermore, ink that is not ejected from each nozzle N of the nozzle array Lb and remains in the liquid storage chamber Rb is discharged through the outlet Rb_out.

[0039] Fig. 5 is a cross-sectional view showing an example of the configuration of the head chip HC. As shown in Fig. 5, the head chip HC includes a communication plate 18a, a pressure chamber substrate 18b, a nozzle plate 18c, a compliance substrate 18d, a diaphragm 18e, a plurality of drive elements Ea and Eb, a cover 18g, a case 18h, a wiring substrate 18i, and a drive circuit 18j.

[0040] The communication plate 18a and the pressure chamber substrate 18b are stacked in this order in the Z1 direction to form a flow path for supplying ink to the multiple nozzles N. A diaphragm 18e, multiple drive elements Ea and Eb, a cover 18g, a case 18h, a wiring board 18i, and a drive circuit 18j are installed in an area located further in the Z1 direction than the stack of communication plate 18a and pressure chamber substrate 18b. On the other hand, a nozzle plate 18c and a compliance board 18d are installed in an area located further in the Z2 direction than the stack. Each element of the head chip HC is roughly a plate-like member elongated in the Y direction and joined to each other by, for example, adhesive or direct bonding. Each element of the head chip HC will be described below in order with reference to FIG. 5.

[0041] The nozzle plate 18c is a plate-like member laminated on the communication plate 18a and having a plurality of nozzles N in each of the nozzle rows La and Lb. Each of the nozzles N is a through-hole that allows ink to pass through. The ink is ejected by pressure fluctuations in the pressure chambers Ca and Cb caused by the vibration of the diaphragm 18e due to the drive of the drive elements Ea and Eb. The surface of the nozzle plate 18c facing the Z2 direction constitutes the nozzle surface FN. The nozzle plate 18c is manufactured by processing a silicon single crystal substrate using semiconductor manufacturing techniques, such as dry etching or wet etching. However, other known methods and materials may also be used to manufacture the nozzle plate 18c. The cross-sectional shape of the nozzle is typically circular, but is not limited thereto and may be non-circular, such as polygonal or elliptical.

[0042] The communication plate 18a is provided with spaces R1a and R1b, a plurality of supply channels RRa and RRb, and a plurality of communication channels NRa and NRb as channels communicating with the nozzles N for each of the nozzle rows La and Lb. Each of the spaces R1a and R1b is an elongated opening extending in the direction along the Y axis in a plan view seen in the direction along the Z axis. Each of the supply channels RRa and RRb and the communication channels NRa and NRb is a through hole formed for each nozzle N. Each supply channel RRa communicates with the space R1a. Each supply channel RRb communicates with the space R1b.

[0043] The communicating plate 18a has a pair of plate surfaces, and the nozzle plate 18c and compliance substrate 18d are stacked on the first surface F1, which is the surface facing the Z2 direction. The aforementioned spaces R1a, R1b and communicating channels NRa, NRb open on the first surface F1. The communicating plate 18a also has a second surface F2, which is formed by half-etching when forming the spaces R1a, R1b. The second surface F2 is the surface that defines the spaces R1a, R1b and faces the Z2 direction.

[0044] The pressure chamber substrate 18b is a plate-shaped member in which a plurality of pressure chambers Ca and a plurality of pressure chambers Cb are provided. The plurality of pressure chambers Ca are arranged in a direction along the Y-axis. Similarly, the plurality of pressure chambers Cb are arranged in a direction along the Y-axis. Each pressure chamber Ca is formed for each nozzle N of the nozzle row La and is an elongated space extending in a direction along the X-axis in a plan view. Similarly, each pressure chamber Cb is formed for each nozzle N of the nozzle row Lb and is an elongated space extending in a direction along the X-axis in a plan view. Like the nozzle plate 18c described above, the communication plate 18a and the pressure chamber substrate 18b are each manufactured by processing a silicon single crystal substrate using semiconductor manufacturing technology, for example. However, other known methods and materials may be used as appropriate to manufacture the communication plate 18a and the pressure chamber substrate 18b.

[0045] The pressure chamber Ca is in communication with both the communication flow path NRa and the supply flow path RRa. Therefore, the pressure chamber Ca is in communication with the nozzles N of the nozzle row La via the communication flow path NRa, and is in communication with the space R1a via the supply flow path RRa. Similarly, the pressure chamber Cb is in communication with both the communication flow path NRb and the supply flow path RRb. Therefore, the pressure chamber Cb is in communication with the nozzles N of the nozzle row Lb via the communication flow path NRb, and is in communication with the space R1b via the supply flow path RRb.

[0046] A diaphragm 18e is disposed on the surface of the pressure chamber substrate 18b facing the Z1 direction. The diaphragm 18e is a plate-like member that can vibrate elastically. The diaphragm 18e has, for example, a first layer and a second layer, which are stacked in this order in the Z1 direction. The first layer is, for example, an elastic film made of silicon oxide (SiO2). The elastic film is formed, for example, by thermally oxidizing one surface of a silicon single crystal substrate. The second layer is, for example, an insulating film made of zirconium oxide (ZrO2). The insulating film is formed, for example, by forming a zirconium layer by sputtering and then thermally oxidizing the layer. Note that the diaphragm 18e is not limited to the configuration of the stacked first and second layers described above, and may be, for example, a single layer or three or more layers.

[0047] A plurality of drive elements Ea and a plurality of drive elements Eb are arranged on the surface of the diaphragm 18e facing the Z1 direction. Each of the drive elements Ea and Eb is a passive element that deforms when a drive signal is supplied. Each of the drive elements Ea and Eb has an elongated shape extending in a direction along the X axis in a planar view. The plurality of drive elements Ea are arranged in a direction along the Y axis so as to correspond to the plurality of pressure chambers Ca. The drive elements Ea overlap the pressure chambers Ca in a planar view. Similarly, the plurality of drive elements Eb are arranged in a direction along the Y axis so as to correspond to the plurality of pressure chambers Cb. The drive elements Eb overlap the pressure chambers Cb in a planar view.

[0048] Each of the drive elements Ea and Eb has a first electrode, a piezoelectric layer, and a second electrode, which are stacked in this order in the Z1 direction (not shown). One of the first and second electrodes is an individual electrode spaced apart from each other and arranged for each drive element Ea or Eb, and a drive signal is applied to the individual electrode. The other of the first and second electrodes is a strip-shaped common electrode extending continuously along the Y-axis across multiple drive elements Ea or multiple drive elements Eb, and a predetermined reference potential is supplied to the other electrode. Examples of metal materials for these electrodes include platinum (Pt), aluminum (Al), nickel (Ni), gold (Au), and copper (Cu). These materials can be used singly or in combination of two or more in the form of an alloy or a laminate. The piezoelectric layer is made of a piezoelectric material such as lead zirconate titanate (Pb(Zr,Ti)O3) and has, for example, a strip shape extending continuously along the Y axis across the plurality of drive elements Ea or the plurality of drive elements Eb. However, a piezoelectric layer may be provided individually for each drive element Ea or each drive element Eb. When the vibration plate 18e vibrates in response to the deformation of the drive element Ea, the pressure in the pressure chamber Ca fluctuates, causing ink to be ejected from the nozzle N of the nozzle array La. Similarly, when the vibration plate 18e vibrates in response to the deformation of the drive element Eb, the pressure in the pressure chamber Cb fluctuates, causing ink to be ejected from the nozzle N of the nozzle array Lb. Note that instead of the drive elements Ea and Eb, heating elements that heat the ink in the pressure chambers Ca and Cb may be used as the drive elements.

[0049] Cover 18g is a plate-like member installed on the surface of diaphragm 18e facing the Z1 direction, and protects the multiple drive elements Ea and multiple drive elements Eb and reinforces the mechanical strength of diaphragm 18e. Here, the multiple drive elements Ea and multiple drive elements Eb are housed between cover 18g and diaphragm 18e. Cover 18g is made of, for example, a resin material.

[0050] The case 18h is a case for storing ink to be supplied to the multiple pressure chambers Ca and the multiple pressure chambers Cb. The case 18h is made of, for example, a resin material. The case 18h is provided with spaces R2a and R2b, inlets Ra_in and Rb_in, and outlets Ra_out and Rb_out. The space R2a is a space that communicates with the aforementioned space R1a and, together with the space R1a, functions as a liquid storage chamber Ra, which is a reservoir that stores ink to be supplied to the multiple pressure chambers Ca. The ink in the liquid storage chamber Ra is supplied to the pressure chambers Ca via each supply flow path RRa. Similarly, the space R2b is a space that communicates with the aforementioned space R1b and, together with the space R1b, functions as a liquid storage chamber Rb, which is a reservoir that stores ink to be supplied to the multiple pressure chambers Cb. The ink in the liquid storage chamber Rb is supplied to the pressure chambers Cb via each supply flow path RRb.

[0051] The compliance substrate 18d is a substrate that absorbs pressure fluctuations of ink inside the liquid storage chambers Ra and Rb, which are flow paths that communicate with the multiple nozzles N. The compliance substrate 18d is stacked on the communication plate 18a at a position different from that of the nozzle plate 18c. In other words, the compliance substrate 18d and the nozzle plate 18c are stacked on the surface of the communication plate 18a facing the Z2 direction so that they do not overlap each other.

[0052] Compliance substrate 18d includes compliance film 18d1 and frame 18d2. Compliance film 18d1 is a flexible resin film that forms the wall surfaces of liquid storage chambers Ra and Rb. The surface of compliance film 18d1 facing the Z1 direction is bonded to communication plate 18a with an adhesive such as an epoxy adhesive. Meanwhile, frame 18d2 is bonded to the surface of compliance film 18d1 facing the Z2 direction with an adhesive such as a urethane adhesive or an epoxy adhesive. Frame 18d2 is a frame-shaped member that forms compliance spaces Rca and Rcb. Frame 18d2 is made of a metal material such as stainless steel, aluminum, titanium, or a magnesium alloy. Compliance substrate 18d may also be a flexible thin metal plate.

[0053] Although not shown, the surface of frame 18d2 facing the Z2 direction is bonded to the aforementioned fixed plate 14 with an adhesive such as an epoxy adhesive. Here, compliance spaces Rca and Rcb are defined by frame 18d2 between compliance film 18d1 and fixed plate 14. Compliance space Rca is separated from liquid storage chamber Ra via compliance film 18d1, and is a space that allows deformation of compliance film 18d1 in response to pressure changes in the ink within liquid storage chamber Ra. Compliance space Rcb is separated from liquid storage chamber Rb via compliance film 18d1, and is a space that allows deformation of compliance film 18d1 in response to pressure changes in the ink within liquid storage chamber Rb.

[0054] 5, frame 18d2 has a pair of openings 18d2a for forming compliance spaces Rca and Rcb and a pair of slits 18d2b that function as escape portions for the adhesive. Each of the pair of openings 18d2a is a hole that penetrates frame 18d2 in the thickness direction and has a shape that extends in the direction along the Y axis when viewed in the direction along the Z axis. The pair of slits 18d2b is disposed between the pair of openings 18d2a and is a hole that penetrates frame 18d2 in the thickness direction and has a shape that extends in the direction along the Y axis when viewed in the direction along the Z axis. Note that slits 18d2b that function as escape portions for the adhesive may be provided as needed and may be omitted.

[0055] The wiring board 18i is mounted on the surface of the diaphragm 18e facing the Z1 direction and is a mounting component for electrically connecting the control unit 20 and the head chip HC. The wiring board 18i is a flexible wiring board such as a COF (Chip On Film), an FPC (Flexible Printed Circuit), or an FFC (Flexible Flat Cable). In this embodiment, a drive circuit 18j for supplying drive voltages to the drive elements Ea and Eb is mounted on the wiring board 18i. The drive circuit 18j is a circuit that switches whether or not to supply at least a portion of the waveform included in the drive signal D as a drive pulse based on the control signal S.

[0056] 1-4.Fixing plate Fig. 6 is a plan view showing the positional relationship between the nozzle plate 18c, the opening 14a of the fixed plate 14, and the compliance spaces Rca and Rcb of the compliance substrate 18d. Fig. 6 shows a part of the liquid jet head 1 as seen in the Z1 direction. Note that in Fig. 6, the shape of the frame 18d2 of the compliance substrate 18d is indicated by a dashed line.

[0057] 6, the fixed plate 14 is laminated on the compliant substrate 18d so as to cover the compliant substrate 18d when viewed in the Z1 direction. That is, the fixed plate 14 is laminated on the surface of the compliant substrate 18d facing the Z2 direction, over an area that includes the compliant substrate 18d when viewed in the Z1 direction.

[0058] Here, the nozzle plate 18c is located inside the opening 14a of the fixed plate 14 when viewed in the Z1 direction. That is, the nozzle plate 18c is disposed inside the periphery EG of the opening 14a when viewed in the Z1 direction. On the other hand, the compliance substrate 18d is disposed outside the periphery EG of the opening 14a when viewed in the Z1 direction, and is stacked on the communication plate 18a at a position different from that of the nozzle plate 18c.

[0059] As can be seen from the above, when viewed in the Z1 direction, the periphery EG of the opening 14a is disposed between the compliance substrate 18d and the nozzle plate 18c.

[0060] 6, the periphery EG of the opening 14a is shaped to follow the outline of the nozzle plate 18c when viewed in the Z1 direction. Specifically, the nozzle plate 18c is shaped like a rectangle with its longitudinal direction along the Y-axis when viewed in the Z1 direction, and the periphery EG of the opening 14a is shaped like a rectangle that follows the outline of the nozzle plate 18c when viewed in the Z1 direction. Furthermore, the frame 18d2 of the compliance substrate 18d has an opening 18d2c that encompasses the opening 14a when viewed in the Z1 direction, and the opening 18d2c is shaped like a rectangle that follows the periphery EG of the opening 14a when viewed in the Z1 direction.

[0061] As described above, compliance spaces Rca and Rcb, which are spaces for allowing deformation of the compliance substrate 18d, are provided between the fixed plate 14 and the compliance substrate 18d. The compliance space Rca has an elongated shape extending in the direction in which the multiple nozzles N of the nozzle row La are arranged. Similarly, the compliance space Rcb has an elongated shape extending in the direction in which the multiple nozzles N of the nozzle row Lb are arranged.

[0062] Holes 14b for opening the compliance spaces Rca and Rcb to the atmosphere are provided in the fixed plate 14. The holes 14b are arranged at positions overlapping with one end of each of the compliance spaces Rca and Rcb in the longitudinal direction when viewed in the thickness direction of the fixed plate 14.

[0063] Fig. 7 is a cross-sectional view of the liquid jet head 1 according to the first embodiment. Fig. 7 is a cross-sectional view taken along line BB in Fig. 6. Note that, although Fig. 7 representatively shows the configuration of the nozzle row La of the liquid jet head 1, the configuration of the nozzle row Lb of the liquid jet head 1 is the same as the configuration of the nozzle row La of the liquid jet head 1.

[0064] 7, the liquid jet head 1 includes a mold 18f that closes the gap between the nozzle plate 18c and the fixed plate 14. The mold 18f has the function of reducing the step between the fixed plate 14 and the nozzle plate 18c and protecting the adhesive portion between the compliance substrate 18d and the communication plate 18a. The mold 18f is made of a resin composition that includes a thermosetting resin such as an epoxy resin. The resin composition may include an inorganic filler such as silica or alumina.

[0065] In the liquid jet head 1, when liquid such as ink is jetted from the nozzles N, a mist may be generated. This mist may enter the compliance spaces Rca, Rcb through the holes 14b. If liquid exists in the compliance spaces Rca, Rcb, the liquid may hinder the deformation of the compliance substrate 18d, which may cause abnormalities in the jetting characteristics of the head chip HC.

[0066] Therefore, fixed plate 14 is configured to be transparent to visible light, infrared light, or X-rays in at least a part of the area that overlaps with compliance spaces Rca, Rcb when viewed in the thickness direction of fixed plate 14. This makes it possible to observe whether or not there is liquid pooling in compliance spaces Rca, Rcb, which are spaces provided between head chip HC and fixed plate 14, without removing fixed plate 14.

[0067] In this embodiment, the fixing plate 14 is made of a material that is transmissive to visible light, infrared light, or X-rays. Examples of materials that are transmissive to visible light include transparent materials such as glass, quartz, and transparent resins such as polyethylene terephthalate (PET), polypropylene (PP), and polyvinyl chloride (PVC). By making the fixing plate 14 of a transparent material, the liquid pools in the compliance spaces Rca and Rcb can be observed with a sensor in the visible light range or by visual inspection. In this specification, "transparent" refers to the ability to transmit visible light, and includes colorless transparency as well as colored transparency. Hereinafter, a material that is transmissive to visible light may be referred to as a "transparent material."

[0068] An example of a material that can transmit infrared light is silicon (Si). When the fixing plate 14 is made of a material that can transmit infrared light, the puddles in the compliance spaces Rca and Rcb can be observed using a sensor in the infrared light range. Furthermore, in this case, because the fixing plate 14 does not transmit visible light or light in the ultraviolet light range, even when curable ink such as an ultraviolet-curable ink is used, the ink is prevented from unintentionally curing when observing the puddles in the compliance spaces Rca and Rcb.

[0069] Examples of materials that are transmissive to X-rays include non-metallic materials such as resin. When the fixing plate 14 is made of a material that is transmissive to X-rays, the puddles in the compliance spaces Rca and Rcb can be observed using an X-ray sensor or the like. In this case, the non-metallic material is preferably an opaque material, i.e., a material that does not transmit visible light, specifically, an opaque resin such as polyimide. As a result, since the fixing plate 14 does not transmit visible light or light in the ultraviolet range, even when using curable ink such as an ultraviolet-curable ink, the ink is prevented from unintentionally curing when observing the puddles in the compliance spaces Rca and Rcb.

[0070] The thickness of the fixing plate 14 is not particularly limited as long as it is thick enough to transmit visible light, infrared light, or X-rays, but is, for example, 0.03 mm or more and 5 mm or less.

[0071] As described above, in the first embodiment, it is possible to observe whether or not there are pools of liquid in the compliance spaces Rca and Rcb without removing the fixing plate 14.

[0072] 2. Second embodiment A second embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions and functions are similar to those of the first embodiment, the reference numerals used in the description of the first embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0073] 8 is a cross-sectional view of a liquid jet head 1A according to the second embodiment. The liquid jet head 1A has the same configuration as the liquid jet head 1 of the first embodiment, except that it includes a fixing plate 14A instead of the fixing plate 14 of the first embodiment.

[0074] As shown in FIG. 8, the fixed plate 14A has a first layer LA1 and a second layer LA2.

[0075] The first layer LA1 is missing at least a portion of the area overlapping the compliance spaces Rca and Rcb in the thickness direction of the fixed plate 14A. The first layer LA1 has an opening 14c. The opening 14c is provided at a position overlapping at least a portion of the compliance spaces Rca and Rcb in the thickness direction of the fixed plate 14, and forms a window for transmitting visible light, infrared light, or X-rays. In the example shown in FIG. 8, the opening 14c coincides with the opening 18d2a of the frame 18d2. Note that the opening 14c is not limited to the example shown in FIG. 8, and may be provided at a position overlapping only a portion of the compliance spaces Rca and Rcb in the thickness direction of the fixed plate 14.

[0076] The material constituting the first layer LA1 is not particularly limited and may be either a transparent material or an opaque material, but from the viewpoint of increasing the rigidity of the fixing plate 14A, it is preferable that the material has a higher Young's modulus than the material constituting the second layer LA2, and specifically, it is preferable that the material be an opaque material such as metal.

[0077] The first layer LA1 is fixed to the head chip HC with an adhesive, etc. The thickness of the first layer LA1 is not particularly limited, but is, for example, not less than 0.03 mm and not more than 5 mm.

[0078] The second layer LA2 is provided over a range that encompasses at least a portion of the area that overlaps with the compliance spaces Rca and Rcb when viewed in the thickness direction of the fixing plate 14A, and is laminated on the first layer LA1. That is, the second layer LA2 is laminated on the first layer LA1 so as to cover the opening 14c of the first layer LA1. Note that the second layer LA2 may have a different shape from the first layer LA1 in the area other than the opening 14c of the first layer LA1.

[0079] The second layer LA2 is made of a transparent material. This allows the presence or absence of liquid pools in the compliance spaces Rca and Rcb to be observed through the opening 14c in the first layer LA1 and the second layer LA2. In this way, by having the first layer LA1 and the second layer LA2 in the fixing plate 14A, it is possible to observe the liquid pools in the compliance spaces Rca and Rcb while suitably ensuring the mechanical strength required for the fixing plate 14A.

[0080] In this embodiment, the second layer LA2, the first layer LA1, and the compliance substrate 18d are stacked in this order in the Z1 direction. Therefore, the first layer LA1 is disposed between the second layer LA2 and the compliance substrate 18d. This prevents convex portions due to the shape of the first layer LA1 from appearing on the outer surface of the fixed plate 14A, allowing the outer surface of the fixed plate 14A to be flat. As a result, even if a liquid such as ink adheres to the outer surface of the fixed plate 14A, the liquid can be easily wiped off. Furthermore, since the first layer LA1 functions as a spacer to form a space between the second layer LA2 and the head chip HC, it also has the advantage of making it easier to increase the volume of the compliance spaces Rca and Rcb. Increasing the volume of the compliance spaces Rca and Rcb contributes to increasing the displacement of the compliance substrate 18d and improving the responsiveness of the compliance substrate 18d to sudden pressure changes in the flow passages communicating with the nozzles N. The second layer LA2 may be disposed between the first layer LA1 and the compliance substrate 18d. Even in this case, the mechanical strength required for the fixing plate 14A can be easily increased.

[0081] The second layer LA2 is fixed to the first layer LA1 with an adhesive, etc. The thickness of the second layer LA2 is not particularly limited, but is, for example, not less than 0.01 mm and not more than 5 mm.

[0082] According to the second embodiment described above, it is also possible to observe whether or not there are pools of liquid in the compliance spaces Rca and Rcb without removing the fixed plate 14A.

[0083] 3. Third embodiment A third embodiment of the present disclosure will be described below. In the following exemplary embodiments, elements whose actions and functions are similar to those of the first embodiment will be designated by the same reference numerals as those used in the description of the first embodiment, and detailed descriptions thereof will be omitted where appropriate.

[0084] 9 is a cross-sectional view of a liquid jet head 1B according to a third embodiment. The liquid jet head 1B has the same configuration as the liquid jet head 1 of the first embodiment, except that it includes a fixing plate 14B instead of the fixing plate 14 of the first embodiment.

[0085] The fixed plate 14B is provided with a plurality of through holes 14d. The plurality of through holes 14d penetrate the fixed plate 14 in at least a portion of the area where the fixed plate 14 overlaps with the compliance spaces Rca and Rcb when viewed in the thickness direction of the fixed plate 14. The size, number, shape, and other aspects of the through holes 14d are not particularly limited and may be any. From the viewpoint of making it easy to observe the presence or absence of liquid pools in the compliance spaces Rca and Rcb, it is preferable that the area ratio of the through holes 14d present per unit area, i.e., the presence rate of the through holes 14d, is 50% or more.

[0086] Each of the through holes 14d is filled with a transparent material. This allows a fixing plate 14B that allows visible light to pass through to be easily obtained by processing an existing fixing plate. Here, a resin such as an existing adhesive can be used as the transparent material. In the example shown in FIG. 9, the surfaces of the transparent portion 14e formed by the transparent material filled in the through holes 14d, facing the Z1 direction and the Z2 direction, are flat surfaces that are flush with the plate surfaces of the other portions of the fixing plate 14B. The surfaces of the transparent portion 14e facing the Z1 direction and the Z2 direction are not limited to flat surfaces, and may be, for example, convex or concave curved surfaces like a lens.

[0087] According to the third embodiment described above, it is also possible to observe whether or not there is liquid pooling in the compliance spaces Rca and Rcb without removing the fixed plate 14B.

[0088] 4. Fourth embodiment A fourth embodiment of the present disclosure will be described below. In the following exemplary embodiments, elements whose actions and functions are similar to those of the first embodiment will be designated by the same reference numerals as those used in the description of the first embodiment, and detailed descriptions thereof will be omitted as appropriate.

[0089] 10 is a plan view illustrating a fixed plate 14C according to the fourth embodiment. The liquid jet head 1C according to the present embodiment has the same configuration as the liquid jet head 1 according to the first embodiment, except that it includes a fixed plate 14C instead of the fixed plate 14 according to the first embodiment.

[0090] The fixed plate 14C is configured in the same manner as the fixed plate 14A of the second embodiment or the fixed plate 14B of the third embodiment described above, except that only the portion 14f shown by the two-dot chain line in Figure 10 is configured to be transparent to visible light, infrared light, or X-rays.

[0091] Portion 14f overlaps the longitudinal ends of compliance spaces Rca and Rcb when viewed in the thickness direction of fixed plate 14C. This allows for convenient observation of the formation of pools of liquid in compliance spaces Rca and Rcb when atmospherically open holes 14b are provided at the longitudinal ends of compliance spaces Rca and Rcb. This is because pools of liquid in compliance spaces Rca and Rcb are formed by the intrusion of moisture through the holes. Furthermore, by making only portion 14f of fixed plate 14C transparent by employing the configuration of the second or third embodiment described above, the mechanical strength required for fixed plate 14C can be suitably ensured.

[0092] According to the fourth embodiment described above, it is also possible to observe whether or not there are pools of liquid in the compliance spaces Rca and Rcb without removing the fixing plate 14C.

[0093] 5. Variations The above-described exemplary embodiments can be modified in various ways. Specific modified embodiments that can be applied to the above-described embodiments are exemplified below. Two or more embodiments arbitrarily selected from the following examples can be combined as appropriate to the extent that they are not mutually contradictory.

[0094] 5-1. Variation 1 In the above-described embodiment, an example is given in which the liquid jet head has four head chips, but this is not the only possible embodiment, and the number of head chips that the liquid jet head has may be three or less, or five or more. Furthermore, when the liquid jet head has a plurality of head chips, the arrangement of the plurality of head chips is not limited to the above-described embodiment and may be arbitrary. Furthermore, the shape of the liquid jet head is also not limited to the above-described embodiment and may be arbitrary.

[0095] 5-2. Variation 2 In the above-described embodiment, a serial type liquid ejection device 100 was exemplified, in which a conveying body 41 carrying a liquid ejection head 1 is moved back and forth in the width direction of the medium M, but the liquid ejection device may also be a line type in which multiple nozzles N are distributed across the entire width of the medium M.

[0096] 5-3. Variation 3 The liquid ejection apparatus exemplified in the above-described embodiment can be employed in various devices such as facsimile machines and copiers, in addition to devices dedicated to printing. However, the uses of the liquid ejection apparatus are not limited to printing. For example, a liquid ejection apparatus that ejects a solution of a coloring material is used as a manufacturing apparatus for forming color filters for display devices such as liquid crystal display panels. Furthermore, a liquid ejection apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus for forming wiring and electrodes on a wiring board. Furthermore, a liquid ejection apparatus that ejects a solution of an organic substance related to a living body is used as a manufacturing apparatus for manufacturing biochips, for example.

[0097] 6. Notes A summary of this disclosure is provided below.

[0098] (Appendix 1) A first aspect, which is a preferred example of a liquid ejection head of the present disclosure, comprises a plurality of head chips including a nozzle plate having a plurality of nozzles for ejecting liquid, and a fixed plate to which the plurality of head chips are fixed and which has a plurality of openings for exposing the nozzle plate to the outside, wherein each of the plurality of head chips includes a compliance substrate for absorbing pressure fluctuations in flow paths communicating with the plurality of nozzles, and a compliance space, which is a space for allowing deformation of the compliance substrate, is provided between the fixed plate and the compliance substrate, and the fixed plate is capable of transmitting visible light, infrared light, or X-rays in at least a portion of the area that overlaps with the compliance space when viewed in the thickness direction of the fixed plate.

[0099] In the above-described embodiment, the fixed plate is capable of transmitting visible light, infrared light, or X-rays in at least a portion of the area that overlaps with the compliance space when viewed in the thickness direction of the fixed plate, so that it is possible to observe whether or not there is a liquid pool in the compliance space, which is the space provided between the head chip and the fixed plate, without removing the fixed plate.

[0100] (Note 2) In a second aspect, which is a preferred example of the first aspect, the fixing plate is made of a transparent material. In the above aspect, the liquid pool in the compliance space can be observed with a sensor in the visible light range or visually.

[0101] (Note 3) In a third aspect, which is a preferred example of the first aspect, the fixing plate has a first layer having at least a portion missing, and a second layer provided over an area including the at least a portion and laminated on the first layer, the second layer being made of a transparent material. In this aspect, the fixing plate can be provided with the required mechanical strength while allowing observation of the liquid pool in the compliance space.

[0102] (Supplementary Note 4) In the fourth aspect, which is a preferred example of the third aspect, the first layer is disposed between the second layer and the compliance substrate. In the above aspect, the outer surface of the fixing plate can be made flat. As a result, when a liquid such as ink adheres to the outer surface of the fixing plate, the liquid can be easily wiped off. In addition, since the first layer functions as a spacer to form a space between the second layer and the head chip, there is also the advantage that the volume of the compliance space can be easily increased. Increasing the volume of the compliance space contributes to increasing the displacement amount of the compliance substrate and improving the responsiveness of the compliance substrate to sudden pressure changes in the flow path communicating with the nozzle.

[0103] (Supplementary Note 5) In a fifth aspect, which is a preferred example of any of the first to fourth aspects, the compliance space has a longitudinal shape extending in the direction in which the plurality of nozzles are arranged, and the at least one portion overlaps an end of the compliance space in the longitudinal direction when viewed in the thickness direction of the fixing plate. In the above aspect, if an air-opening hole is provided at the end of the compliance space in the longitudinal direction, it is possible to conveniently observe the occurrence of a liquid pool in the compliance space. This is because a liquid pool in the compliance space occurs due to the intrusion of moisture through the hole.

[0104] (Supplementary Note 6) In a sixth aspect which is a preferred example of the first aspect, the fixing plate has a plurality of through holes penetrating the fixing plate in at least a portion thereof, and each of the plurality of through holes is filled with a transparent material. In the above aspect, a fixing plate which is capable of transmitting visible light can be easily obtained by processing an existing fixing plate. [Explanation of symbols]

[0105] 1...liquid ejection head, 1A...liquid ejection head, 1B...liquid ejection head, 1C...liquid ejection head, 14...fixed plate, 14A...fixed plate, 14B...fixed plate, 14C...fixed plate, 14a...opening, 14d...through hole, 14f...portion, 18b...pressure chamber substrate, 18c...nozzle plate, 18d...compliance substrate, HC...head chip, LA1...first layer, LA2...second layer, N...nozzle, Rca...compliance space, Rcb...compliance space.

Claims

1. a plurality of head chips each including a nozzle plate having a plurality of nozzles for ejecting liquid; a fixing plate to which the plurality of head chips are fixed and which has a plurality of openings for exposing the nozzle plate to the outside, each of the plurality of head chips includes a compliance substrate for absorbing pressure fluctuations in flow channels communicating with the plurality of nozzles; a compliance space, which is a space for allowing deformation of the compliance substrate, is provided between the fixed plate and the compliance substrate; the fixation plate is transmissive to visible light, infrared light, or X-rays in at least a part of a region overlapping the compliance space in a thickness direction of the fixation plate; A liquid jet head characterized by:

2. The fixing plate is made of a transparent material. The liquid jet head according to claim 1 .

3. The fixing plate is the first layer having at least a partial defect; a second layer provided over an area including at least the portion and laminated on the first layer; The second layer is made of a transparent material. The liquid jet head according to claim 1 .

4. the first layer is disposed between the second layer and the compliant substrate. The liquid jet head according to claim 3 .

5. the compliance space has a longitudinal shape extending in a direction in which the plurality of nozzles are arranged, the at least one portion is a portion that overlaps an end portion of the compliance space in the longitudinal direction when viewed in the thickness direction of the fixing plate. The liquid jet head according to claim 1 .

6. The fixing plate is provided with a plurality of through holes penetrating the fixing plate in at least the portion, Each of the plurality of through holes is filled with a transparent material. The liquid jet head according to claim 1 .

Images