Liquid spray head

Abstract

Detects near-end damage to the sealant of the liquid injection head. [Solution] The liquid spray head comprises a first member, a second member, and a first sealing material filled between the first member and the second member. The first sealing material has a second layer exposed to the outside of the liquid spray head and a first layer covered by the second layer and not exposed to the outside of the liquid spray head, and the colors of the first layer and the second layer are different from each other.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head.

Background Art

[0002] In a liquid ejection head that ejects a liquid such as ink in an apparatus such as an inkjet printer, a sealing material may be filled in a gap between a plurality of members. For example, the liquid ejection head described in Patent Document 1 has a nozzle plate having a plurality of nozzles and a fixing plate having an opening surrounding the nozzle plate, and a gap between the nozzle plate and the peripheral edge of the opening of the fixing plate is filled with a molding agent.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the liquid ejection head described in Patent Document 1, the molding agent deteriorates due to the adhesion of ink, and as a result, there is a risk of seal failure of the molding agent. Under such circumstances, it is required to be able to detect that the state has reached a state where seal failure of the filler is likely to occur before a problem occurs in the liquid ejection head due to seal failure of the molding agent.

Means for Solving the Problems

[0005] To solve the above problems, a liquid spray head according to a preferred embodiment of the present disclosure is a liquid spray head comprising a first member, a second member, and a first sealing material filled between the first member and the second member, wherein the first sealing material has a second layer exposed to the outside of the liquid spray head and a first layer covered by the second layer and not exposed to the outside of the liquid spray head, and the colors of the first layer and the second layer are different from each other.

[0006] A liquid spray head according to another preferred embodiment of the present disclosure is a liquid spray head comprising a first member having a through hole and a first sealant filling the through hole, wherein the first sealant has a second layer exposed to the outside of the liquid spray head and a first layer covered by the second layer and not exposed to the outside of the liquid spray head, and the colors of the first layer and the second layer are different from each other. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing an example configuration of a liquid injection device using a liquid injection head. [Figure 2] This is a perspective view of a head module having a liquid injection head according to the embodiment. [Figure 3] This is an exploded perspective view of the liquid spray head according to the embodiment. [Figure 4] This figure shows a portion of the cross-section along line AA in Figure 3. [Figure 5] This is a bottom view of the liquid injection head according to the first embodiment. [Figure 6] This is an explanatory diagram of the sealing material that is filled between the nozzle plate and the fixing plate. [Figure 7] Figure 6 is an explanatory diagram of the function of the sealing material shown. [Figure 8] This is an explanatory diagram of the sealing material that is filled between the holder and the fixing plate. [Figure 9] This is an explanatory diagram of the sealing material used to fill the through-holes in the fixing plate and the reinforcing plate. [Figure 10] This is a side view of the liquid injection head according to the embodiment. [Figure 11] This is an explanatory diagram of the sealing material that is filled between the cover and the holder. [Figure 12] This is a diagram illustrating the cover and flow path pipe. [Figure 13] This is an explanatory diagram of the sealing material that is filled between the cover and the flow channel pipe. [Modes for carrying out the invention]

[0008] Preferred embodiments of the present disclosure will be described below with reference to the attached drawings. Note that the dimensions and scale of parts in the drawings may differ from actual dimensions as appropriate, and some parts are shown schematically for ease of understanding. Furthermore, the scope of the present disclosure is not limited to these embodiments unless otherwise stated in the following description.

[0009] For convenience, the following explanation will use the X, Y, and Z axes intersecting each other as appropriate. In the following, one direction along the X axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. Similarly, opposite directions along the Y axis are the Y1 and Y2 directions. Also, opposite directions along the Z axis are the Z1 and Z2 directions.

[0010] The Z1 direction is an example of the "first direction" when the sealing material 85 described later is considered as an example of the "first sealing material". The Z2 direction is an example of the "first direction" when the sealing materials 81, 82, and 83 described later are considered as examples of the "first sealing material". The direction that intersects the Z axis and goes from the inside to the outside of the liquid spray head 1 described later is an example of the "first direction" when the sealing material 84 described later is considered as an example of the "first sealing material".

[0011] However, typically the Z-axis is the vertical axis, and the Z2 direction corresponds to the downward direction in the vertical. However, the Z-axis does not have to be the vertical axis. Also, the X, Y, and Z axes are typically orthogonal to each other, but are not limited to this; for example, they can intersect at an angle within the range of 80° to 100°.

[0012] 1. Embodiment 1-1. Schematic Configuration of Liquid Jetting Device FIG. 1 is a schematic diagram showing a configuration example of a liquid jetting device 100 using a liquid jetting head 1. The liquid jetting device 100 is an inkjet printing device that jets ink, which is an example of "liquid", as droplets onto a medium M. The medium M is typically printing paper. Note that the medium M is not limited to printing paper, and may be a printing target of any material such as a resin film or fabric.

[0013] As shown in FIG. 1, the liquid jetting device 100 includes a liquid container 10, a control unit 20, a conveyance mechanism 30, a movement mechanism 40, a head module 50, a circulation mechanism 60, and a wiping member 70. Hereinafter, based on FIG. 1, these will be briefly described in order.

[0014] The liquid container 10 stores ink. Specific examples of the liquid container 10 include, for example, a cartridge detachable from the liquid jetting device 100, a bag-shaped ink pack formed of a 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 is arbitrary.

[0015] The control unit 20 includes, for example, 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 operations of each element of the liquid jetting device 100.

[0016] The conveyance mechanism 30 conveys the medium M in the conveyance 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 direction and the X2 direction under the control of the control unit 20. In the example shown in FIG. 1, the movement mechanism 40 includes a substantially box-shaped carrier 41 called a carriage that houses the head module 50, and a conveyance belt 42 to which the carrier 41 is fixed. Note that, in addition to the head module 50, the aforementioned liquid container 10 may be mounted on the carrier 41.

[0017] In this embodiment, the moving mechanism 40 not only reciprocates the head module 50 along the X-axis over the entire width of the medium M, but is also movable to a position that overlaps with the wiping member 70 when viewed in the direction along the Z-axis.

[0018] The head module 50, under the control of the control unit 20, sprays ink supplied from the liquid container 10 via the circulation mechanism 60 onto the medium M in the Z2 direction from each of its multiple nozzles. This spraying occurs 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 moving mechanism 40, thereby forming an image of ink on the surface of the medium M. The head module 50 has multiple liquid spray heads 1. Details of the liquid spray heads 1 will be described later with reference to Figures 2 to 13.

[0019] In the example shown in Figure 1, the liquid container 10 is connected to the head module 50 via a circulation mechanism 60. The circulation mechanism 60 supplies ink to the head module 50 and also recovers the ink discharged from the head module 50 for resupply to the head module 50. The operation of the circulation mechanism 60 can suppress the increase in ink viscosity and reduce the accumulation of air bubbles in the ink. The circulation mechanism 60 may be provided as needed or omitted. In other words, the liquid injection device 100 does not need to have a configuration that circulates the ink in the liquid injection head 1.

[0020] The wiping member 70 is a member for wiping the surface of the nozzle plate 18c and the fixed plate 14, which will be described later, of the liquid spray head 1. The wiping member 70 is, for example, a member made of a fibrous material such as a woven or nonwoven fabric, or a porous material such as a sponge, or a blade-shaped member made of an elastic material such as rubber. The wiping member 70 is positioned off-center from the transport area of ​​the medium M in the direction along the X axis. When the wiping member 70 wipes the nozzle plate 18c and the fixed plate 14, the moving mechanism 40 positions the liquid spray head 1 so that it overlaps with the wiping member 70 when viewed in the direction along the Z axis. This enables wiping or cleaning of the nozzle plate 18c and the fixed plate 14 by wiping with the wiping member 70. At this time, the liquid spray head 1 may move in the direction along the X axis relative to the wiping member 70 by the drive of the moving mechanism 40, or the wiping member 70 may move in the direction along the X axis or Y axis relative to the liquid spray head 1 by the drive of a mechanism separate from the moving mechanism 40.

[0021] The wiping member 70 may wipe the nozzle plates 18c of multiple liquid spray heads 1 collectively, or it may selectively and individually wipe the nozzle plate 18c of one of the multiple liquid spray heads 1. Furthermore, the size, shape, arrangement, and other aspects of the wiping member 70 are not limited to the example shown in Figure 1 and are arbitrary. For example, the wiping member 70 may be positioned away from the transport area of ​​the medium M in the X2 direction, or it may be composed of multiple wiping members divided for each liquid spray head 1. In addition to the wiping member 70, the installation location of the wiping member 70 may also be provided with a mechanism for performing suction cleaning to discharge ink from the nozzles N of the liquid spray heads 1 by suction, a mechanism for performing capping to cap all the nozzles N of the liquid spray heads 1, and so on.

[0022] 1-2. Liquid spray head Figure 2 is a perspective view of a head module 50 having a liquid injection head 1 according to an embodiment. As shown in Figure 2, the head module 50 has a support 51 and a plurality of liquid injection heads 1.

[0023] The support 51 is a plate-shaped member that supports multiple liquid spray heads 1. The support 51 is provided with multiple mounting holes 51a. Each liquid spray head 1 is inserted into a mounting hole 51a and fixed to the support 51 by screws or the like. The multiple liquid spray heads 1 are arranged in a matrix along the X and Y axes.

[0024] The number and arrangement of the liquid injection heads 1 in the head module 50 are not limited to the example shown in Figure 2 and are arbitrary. Similarly, the shape of the support body 51 is not limited to the example shown in Figure 2 and is arbitrary.

[0025] Figure 3 is an exploded perspective view of the liquid injection head 1 according to the embodiment. As shown in Figure 3, the liquid injection head 1 comprises a flow channel 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 order of cover 16, wiring board 12, flow channel structure 11, holder 13, four head chips HC, reinforcing plate 15, and fixing plate 14 in the Z2 direction.

[0026] Here, holder 13 is an example of a "first component" or "second component" when the sealing material 82 described later is considered as an example of a "first sealing material". Also, holder 13 is an example of a "first component" or "second component" when the sealing material 84 described later is considered as an example of a "first sealing material". Fixing plate 14 is an example of a "first component" or "second component" when the sealing material 81 described later is considered as an example of a "first sealing material". Also, fixing plate 14 is an example of a "first component" or "second component" when the sealing material 82 described later is considered as an example of a "first sealing material". Cover 16 is an example of a "first component" or "second component" when the sealing material 85 described later is considered as an example of a "first sealing material". Also, cover 16 is an example of a "first component" or "second component" when the sealing material 84 described later is considered as an example of a "first sealing material". Furthermore, the cover 16 is an example of a "first member" or "second member" when the sealing material 85 described later is considered as an example of a "first sealing material". The laminate consisting of the fixing plate 14 and the reinforcing plate 15 is an example of a "first member" when the sealing material 83 described later is considered as a "first sealing material". Note that when the sealing material 83 described later is considered as a "first sealing material", the fixing plate 14 may also be considered as an example of a "first member".

[0027] The following is a schematic description of each part of the liquid injection head 1 based on Figure 3.

[0028] The flow channel structure 11 is a structure in which a flow channel is provided inside for supplying ink from the circulation mechanism 60 to four head chips HC. The flow channel structure 11 has a flow channel member 11a and four flow channel tubes 11b. The flow channel tubes 11b are examples of the "first member" or "second member" when the sealing material 85 described later is considered as the "first sealing material".

[0029] Although not shown in Figure 3, the flow channel member 11a is provided with a supply channel for supplying ink to four head chips HC and a discharge channel for discharging ink from the four head chips HC. Thus, the flow channel member 11a has a channel that communicates with the nozzle N, which will be described later.

[0030] The flow channel member 11a has multiple substrates Su1 to Su5, and these layers are stacked in this order in the Z2 direction. 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 multiple substrates Su1 to Su5 are joined to each other by an adhesive such as an epoxy adhesive. The number and thickness of the substrates constituting the flow channel member 11a are not limited to the example shown in Figure 3 and are arbitrary.

[0031] Each flow channel pipe 11b is a tubular body that protrudes from the surface of the flow channel member 11a facing the Z1 direction, and connects the outside of the liquid injection head 1 to the flow channel of the flow channel member 11a. Of the four flow channel pipes 11b, each of two flow channel pipes 11b is connected to the aforementioned supply channel, and each of the remaining two flow channel pipes 11b is connected to the aforementioned discharge channel.

[0032] The wiring board 12 is a mounting component for electrically connecting the liquid injection head 1 to the control unit 20. The wiring board 12 is made of, for example, a flexible wiring board or a rigid wiring board. The wiring board 12 is placed on the flow channel structure 11, and the flow channel structure 11 faces the surface of the wiring board 12 facing in the Z2 direction. On the other hand, a connector 12a is installed on the surface of the wiring board 12 facing in the Z1 direction. The connector 12a is a connecting component for electrically connecting the liquid injection head 1 and the control unit 20. In addition, although not shown, wiring connected to four head chips HC is connected to the wiring board 12. This wiring is made of, for example, a combination of flexible wiring boards and rigid wiring boards. Note that this wiring may be made integrally with the wiring board 12.

[0033] 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 channels 13a, a plurality of wiring holes 13b, and a plurality of recesses 13c. Each of the plurality of holder channels 13a is a hole for flowing ink between the head chip HC and the channel structure 11. The holder channels 13a are provided in correspondence with the inlet Ra_in, Rb_in and outlet Ra_out, Rb_out, respectively, which will be described later. Each of the plurality of wiring holes 13b is a hole through which wiring (not shown) connecting the head chip HC and the wiring board 12 passes. Each of the plurality of recesses 13c has an opening 13d that opens in the Z2 direction, and the recess 13c is a space in which the head chip HC is placed.

[0034] Here, the holder 13 has a surface F8 that intersects the Z-axis and faces in a direction from the inside to the outside of the liquid spray head 1, as shown in Figures 10 and 11 described later. Surface F8 is an example of the "first surface" or "second surface" when the sealing material 84 described later is considered as an example of the "first sealing material". Surface F8 is part of the outer wall surface of the holder 13 and constitutes part of the outer surface of the liquid spray head 1. The holder 13 also has a surface F12 that faces in the Z2 direction, as shown in Figure 8 described later. Surface F12 is an example of the "first surface" or "second surface" when the sealing material 82 described later is considered as an example of the "first sealing material". Furthermore, the holder 13 has an inner circumferential surface F6 of the recess 13c, as shown in Figure 5 described later. The inner circumferential surface F6 defines the opening 13d.

[0035] Each head chip HC ejects ink. Each head chip HC is provided with inlet ports Ra_in and Rb_in and outlet ports Ra_out and Rb_out. Inlet ports Ra_in and Rb_in are openings for introducing ink, respectively. Outlet ports Ra_out and Rb_out are openings for discharging ink, respectively. Each of the inlet ports Ra_in and Rb_in and outlet ports Ra_out and Rb_out are connected to the corresponding holder flow path 13a in a liquid-tight manner by being bonded to each other by adhesive to the head chip HC and the holder 13. An example of the configuration of the head chip HC will be explained later with reference to Figure 4.

[0036] The fixing plate 14 is a plate member for fixing the four head chips HC to the holder 13. Specifically, the fixing plate 14 is positioned between the holder 13 and the four head chips HC, and is fixed to the holder 13 with adhesive. Here, the fixing plate 14 has its thickness direction along the Z axis, and has a surface F2 facing the Z2 direction as shown in Figures 6 and 7 described later. Surface F2 is an example of the "first surface" or "second surface" when the sealing material 81 described later is considered as an example of the "first sealing material". Surface F2 is an example of the "first surface" or "second surface" when the sealing material 82 described later is considered as an example of the "first sealing material". Surface F2 is the surface of the fixing plate 14 that faces outward from the liquid spray head 1, and constitutes a part of the outer surface of the liquid spray head 1. The fixing plate 14 is made of, for example, a metal material. The fixing plate 14 has multiple openings 14a for exposing the nozzle plates 18c of the four head tips HC, which will be described later. Thus, the openings 14a expose the nozzles N, which will be described later. In the example shown in Figure 3, the multiple openings 14a are provided individually for each head tip HC. The fixing plate 14 is also provided with two through holes 14b for positioning relative to the holder 13. The through holes 14b are used, for example, as markers for alignment when bonding the head tips HC to the holder 13 one by one.

[0037] Although not shown in Figure 3, the gap between the inner circumferential surface F4 of the opening 14a and the outer circumferential surface F3 of the nozzle plate 18c (described later) is filled with a sealing material 81, as shown in Figures 6 and 7 (described later). The sealing material 81 is an example of the "first sealing material" when either the nozzle plate 18c or the fixing plate 14 is considered an example of the "first member" and the other is considered an example of the "second member". Furthermore, the gap between the outer circumferential surface F5 of the fixing plate 14 and the inner circumferential surface F6 of the recess 13c of the holder 13 is filled with a sealing material 82, as shown in Figure 8 (described later). The sealing material 82 is an example of the "first sealing material" when either the fixing plate 14 or the holder 13 is considered an example of the "first member" and the other is considered an example of the "second member". In addition, the through hole 14b of the fixing plate 14 is filled with a sealing material 83, as shown in Figure 9 (described later). The sealing material 83 is an example of a "first sealing material" when the fixing plate 14 is considered as an example of a "first component".

[0038] The reinforcing plate 15 is a plate-shaped member positioned between the holder 13 and the fixing plate 14 to reinforce the fixing plate 14. The reinforcing plate 15 is placed on top of the fixing plate 14 and fixed to the fixing plate 14 with adhesive 95. The reinforcing plate 15 is provided with a plurality of openings 15a in which four head tips HC are positioned. The reinforcing plate 15 is made of, for example, a metal material. The reinforcing plate 15 is also provided with two through holes 15b for positioning relative to the holder 13. These two through holes 15b are provided in correspondence with the two through holes 14b mentioned above and overlap with the two through holes 14b when viewed in the direction along the Z axis. The reinforcing plate 15 may be provided as needed and may be omitted.

[0039] The cover 16 is a box-shaped member that houses the flow channel member 11a of the flow channel structure 11 and the wiring board 12. The cover 16 is made of, for example, a resin material. The cover 16 is provided with four openings 16a and four openings 16b. The four openings 16a correspond to the four flow channel pipes 11b of the flow channel structure 11, and the corresponding flow channel pipe 11b is inserted into each opening 16a. A connector 12a is passed through the opening 16b from the inside to the outside of the cover 16.

[0040] Here, the cover 16 has a surface F9 that intersects the Z-axis and faces in a direction from the inside to the outside of the liquid spray head 1, as shown in Figures 10 and 11 described later. Surface F9 is an example of the "first surface" or "second surface" when the sealing material 84 described later is considered as an example of the "first sealing material". Surface F9 is part of the outer wall surface of the cover and constitutes part of the outer surface of the liquid spray head 1.

[0041] Although not shown in Figure 3, the gap between the cover 16 and the holder 13 is filled with a sealing material 84, which will be described later. The sealing material 84 is an example of a "first sealing material" when one of the cover 16 and the holder 13 is considered an example of a "first member" and the other is considered an example of a "second member". The cover 16 also has an inner circumferential surface F11 that defines the opening 16a. On the other hand, the flow channel pipe 11b has an outer circumferential surface F10 that is positioned inside the inner circumferential surface F11 of the cover 16. The gap between the inner circumferential surface F11 of the opening 16a and the outer circumferential surface F10 of the flow channel pipe 11b is filled with a sealing material 85, which will be described later. The sealing material 85 is an example of a "first sealing material" when one of the flow channel pipe 11b and the cover 16 is considered an example of a "first member" and the other is considered an example of a "second member".

[0042] Here, the cover 16 has a surface F14 facing in the Z1 direction, as shown in Figures 12 and 13 described later. Surface F14 is an example of the "first surface" or "second surface" when the sealing material 85 described later is considered as an example of the "first sealing material". Surface F14 is part of the outer wall surface of the cover 16 and constitutes part of the outer surface of the liquid injection head 1. The flow channel pipe 11b also has a surface F13 facing in the Z1 direction, as shown in Figures 12 and 13 described later. Surface F13 is an example of the "first surface" or "second surface" when the sealing material 85 described later is considered as an example of the "first sealing material".

[0043] 1-3. Head Tip Figure 4 shows a portion of the cross-section along line AA in Figure 3. Figure 4 shows the head tip HC, holder 13, fixing plate 14, and reinforcing plate 15 in the cross-section along line AA in Figure 3. As shown in Figure 4, the head tip HC is provided with a plurality of nozzles N for ejecting ink. These plurality of nozzles N are divided into nozzle row La and nozzle row Lb. Nozzle row La and nozzle row Lb are sets of a plurality of nozzles N arranged along the Y axis. Nozzle row La and nozzle row Lb are spaced apart from each other in the direction of the X axis.

[0044] The head tip HC has a liquid storage chamber Ra, a plurality of pressure chambers Ca, and a plurality of drive elements Ea as components corresponding to the nozzle row La. The liquid storage chamber Ra is a common liquid chamber that is continuous across a plurality of nozzles N of the nozzle row La. Each of the pressure chambers Ca and drive elements Ea is provided for each nozzle N of the nozzle row La. The pressure chamber Ca is a space that communicates with the nozzle N. Each of the plurality of pressure chambers Ca is filled with ink supplied from the liquid storage chamber Ra. The drive elements Ea vary the pressure of the ink in the pressure chamber Ca. The drive elements Ea are, for example, piezoelectric elements that change the volume of the pressure chamber Ca by deforming the wall surface of the pressure chamber Ca, or heating elements that generate bubbles in the pressure chamber Ca by heating the ink in the pressure chamber Ca. By varying the pressure of the ink in the pressure chamber Ca, the drive elements Ea cause the ink in the pressure chamber Ca to be ejected from the nozzle N.

[0045] Here, the liquid storage chamber Ra is connected to one inlet Ra_in and one outlet Ra_out, as shown in Figure 3. The ink introduced into the liquid storage chamber Ra from the inlet Ra_in is used as appropriate for ejection from each nozzle N in the nozzle row La. Ink that is not ejected from each nozzle N in the nozzle row La and is stored in the liquid storage chamber Ra is discharged from the outlet Ra_out.

[0046] Furthermore, the head tip HC has a liquid storage chamber Rb, a plurality of pressure chambers Cb, and a plurality of drive elements Eb as components corresponding to the nozzle row Lb. The liquid storage chamber Rb is a common liquid chamber that is continuous across a plurality of nozzles N of the nozzle row Lb. Each of the pressure chambers Cb and drive element Eb is provided for each nozzle N of the nozzle row Lb. Each of the plurality of pressure chambers Cb is filled with ink supplied from the liquid storage chamber Rb. The drive element Eb is, for example, the piezoelectric element or heating element described above. The drive element Eb fluctuates the pressure of the ink in the pressure chamber Cb, causing the ink in the pressure chamber Cb to be ejected from the nozzle N.

[0047] Here, the liquid storage chamber Rb is connected to one inlet Rb_in and one outlet Rb_out, as shown in Figure 3. The ink introduced into the liquid storage chamber Rb from the inlet Rb_in is used as appropriate for ejection from each nozzle N of the nozzle row Lb. Ink that is not ejected from each nozzle N of the nozzle row Lb and is stored in the liquid storage chamber Rb is discharged from the outlet Rb_out.

[0048] As shown in Figure 4, 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, Eb, a cover 18g, and a case 18h. Here, the nozzle plate 18c is an example of a "first member" or "second member" when the sealing material 81 described later is considered as the "first sealing material". The communication plate 18a and the compliance substrate 18d are examples of a "third member" when the sealing material 81 described later is considered as the "first sealing material". Furthermore, the reinforcing plate 15 is an example of a "third member" when the sealing material 82 described later is considered as the "first sealing material". Note that, not limited to the communication plate 18a, the compliance substrate 18d, and the reinforcing plate 15, any member of the liquid injection head 1 that is not exposed to the outside of the liquid injection head 1 may be considered a "third member".

[0049] The communication plate 18a and the pressure chamber substrate 18b are stacked in this order in the Z1 direction, forming a flow path for supplying ink to multiple nozzles N. The region located in the Z1 direction from the stack consisting of the communication plate 18a and the pressure chamber substrate 18b is where the diaphragm 18e, multiple drive elements Ea and Eb, cover 18g, case 18h, wiring board 18i, and drive circuit 18j are installed. On the other hand, the region located in the Z2 direction from the said stack is where the nozzle plate 18c and compliance substrate 18d are installed. Each element of the head chip HC is generally a plate-like member that is elongated in the Y direction, and is joined to each other by means of adhesive or direct bonding, for example. The elements of the head chip HC will be described in order below with reference to Figure 4.

[0050] The nozzle plate 18c is a plate-shaped member laminated on the communication plate 18a and containing multiple nozzles N in nozzle row La and nozzle row Lb, respectively. Each of the multiple nozzles N is a through-hole through which ink passes, and the ink is ejected in the Z2 direction, which is the ejection direction. Here, the nozzle plate 18c has a thickness direction along the Z axis and has a surface F1 facing the Z2 direction, as shown in Figures 6 and 7 described later. Surface F1 is an example of the "first surface" or "second surface" when the sealing material 81 described later is considered as an example of the "first sealing material". Surface F1 is the surface of the pair of plate surfaces of the nozzle plate 18c that faces outward from the liquid ejection head 1 and constitutes a part of the outer surface of the liquid ejection head 1. The nozzle plate 18c is manufactured by processing a silicon single crystal substrate using semiconductor manufacturing technology, for example, dry etching or wet etching. However, other known methods and materials may be used in the manufacture of the nozzle plate 18c as appropriate. Furthermore, while the cross-sectional shape of the nozzle is typically circular, it is not limited to this and may be non-circular, for example, polygonal or elliptical. Here, the nozzle plate 18c is joined to the surface of the communication plate 18a facing the Z2 direction by adhesive (adhesive layer 93 described later).

[0051] The communication plate 18a is provided with spaces R1a and R1b, multiple supply channels RRa and RRb, and multiple communication channels NRa and NRb, respectively, as flow paths communicating with the nozzles N for each of the nozzle rows La and Lb. Spaces R1a and R1b are elongated openings extending in the direction along the Y-axis when viewed in a plan view along the Z-axis. Each of the supply channels RRa and RRb and the communication channels NRa and NRb are through holes formed for each nozzle N. Each supply channel RRa communicates with space R1a. Each supply channel RRb communicates with space R1b.

[0052] On the surface of the communication plate 18a facing the Z2 direction, the nozzle plate 18c and the compliance substrate 18d are laminated, and the aforementioned spaces R1a, R1b and communication channels NRa, NRb are opened.

[0053] The pressure chamber substrate 18b is a plate-shaped member provided with a plurality of pressure chambers Ca and a plurality of pressure chambers Cb. The plurality of pressure chambers Ca are arranged in the direction along the Y axis. Similarly, the plurality of pressure chambers Cb are arranged in the 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 the 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 the direction along the X axis in a plan view. The communication plate 18a and the pressure chamber substrate 18b are manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, similar to the nozzle plate 18c described above. However, other known methods and materials may be used as appropriate for the manufacture of the communication plate 18a and the pressure chamber substrate 18b, respectively.

[0054] Pressure chamber Ca communicates with both the communication channel NRa and the supply channel RRa. Therefore, pressure chamber Ca communicates with the nozzle N of the nozzle row La via the communication channel NRa, and with space R1a via the supply channel RRa. Similarly, pressure chamber Cb communicates with both the communication channel NRb and the supply channel RRb. Therefore, pressure chamber Cb communicates with the nozzle N of the nozzle row Lb via the communication channel NRb, and with space R1b via the supply channel RRb.

[0055] A diaphragm 18e is positioned on the surface of the pressure chamber substrate 18b facing the Z1 direction. The diaphragm 18e is an elastically vibrating plate-shaped member. 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 composed of silicon oxide (SiO2). This elastic film is formed, for example, by thermal oxidation of one surface of a silicon single crystal substrate. The second layer is, for example, an insulating film composed of zirconium oxide (ZrO2). This 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 stacked configuration of the first and second layers described above, and may be composed of, for example, a single layer or three or more layers.

[0056] Multiple drive elements Ea and 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 in response to the supply of a drive signal. Each of the drive elements Ea and Eb is elongated in shape, extending in the direction along the X axis in a plan view. Multiple drive elements Ea are arranged in the direction along the Y axis to correspond to multiple pressure chambers Ca. In a plan view, the drive elements Ea overlap with the pressure chambers Ca. Similarly, multiple drive elements Eb are arranged in the direction along the Y axis to correspond to multiple pressure chambers Cb. In a plan view, the drive elements Eb overlap with the pressure chambers Cb.

[0057] Each of the driving elements Ea and Eb, although not shown in the diagram, has a first electrode, a piezoelectric layer, and a second electrode, and these are stacked in this order in the Z1 direction. One of the first and second electrodes is an individual electrode that is spaced apart from each other for each driving element Ea or driving element Eb, and a driving signal is applied to this electrode. The other electrode is a strip-shaped common electrode that extends along the Y axis so as to be continuous across multiple driving elements Ea or multiple driving elements Eb, and a predetermined reference potential is supplied to this electrode. Examples of metallic materials for these electrodes include platinum (Pt), aluminum (Al), nickel (Ni), gold (Au), and copper (Cu), and one of these can be used alone or two or more can be used in combination in the form of an alloy or stacking. The piezoelectric layer is made of a piezoelectric material such as lead zirconate titanate (Pb(Zr,Ti)O3) and, for example, is a strip-shaped layer extending along the Y-axis so as to be continuous across multiple drive elements Ea or multiple drive elements Eb. However, the piezoelectric layer may be provided individually for each drive element Ea or each drive element Eb. When the diaphragm 18e vibrates in conjunction with 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 row La. Similarly, when the diaphragm 18e vibrates in conjunction with 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 row Lb. In addition, 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 drive elements.

[0058] The cover 18g is a plate-shaped member installed on the surface of the diaphragm 18e facing the Z1 direction, protecting the multiple drive elements Ea and Eb, and reinforcing the mechanical strength of the diaphragm 18e. Here, the multiple drive elements Ea and Eb are housed between the cover 18g and the diaphragm 18e. The cover 18g is made of, for example, a resin material.

[0059] Case 18h is a case for storing ink supplied to multiple pressure chambers Ca and multiple pressure chambers Cb. Case 18h is made of, for example, a resin material. Case 18h is provided with spaces R2a and R2b, inlets Ra_in and Rb_in, and outlets Ra_out and Rb_out. Space R2a is a space that communicates with the aforementioned space R1a and, together with space R1a, functions as a liquid storage chamber Ra, which is a reservoir for storing ink supplied to the multiple pressure chambers Ca. The ink in liquid storage chamber Ra is supplied to pressure chamber Ca via each supply channel RRa. Similarly, space R2b is a space that communicates with the aforementioned space R1b and, together with space R1b, functions as a liquid storage chamber Rb, which is a reservoir for storing ink supplied to the multiple pressure chambers Cb. The ink in liquid storage chamber Rb is supplied to pressure chamber Cb via each supply channel RRb.

[0060] The compliance substrate 18d is a substrate that absorbs pressure fluctuations of the ink in the liquid storage chambers Ra and Rb. The compliance substrate 18d is laminated on the communication plate 18a at a different position from the nozzle plate 18c. That is, the compliance substrate 18d and the nozzle plate 18c are laminated on the surface of the communication plate 18a facing the Z2 direction so that they do not overlap each other.

[0061] The compliance substrate 18d comprises a compliance film 18d1 and a frame 18d2. The compliance film 18d1 is a flexible resin film that constitutes the walls of the liquid storage chambers Ra and Rb. The surface of the compliance film 18d1 facing the Z1 direction is joined to the communication plate 18a with an adhesive such as an epoxy adhesive (adhesive layer 92 described later). On the other hand, the frame 18d2 is joined to the surface of the compliance film 18d1 facing the Z2 direction with an adhesive such as a urethane adhesive or an epoxy adhesive. The frame 18d2 is a frame-shaped member for forming the compliance spaces Rca and Rcb. The frame 18d2 is made of a metallic material such as stainless steel, aluminum, titanium, and magnesium alloy. The compliance substrate 18d may also be a flexible thin plate made of metal.

[0062] The surface of the frame 18d2 facing the Z2 direction is joined to the aforementioned fixing plate 14 by an adhesive such as an epoxy adhesive (adhesive layer 91 described later). Here, compliance spaces Rca and Rcb are formed between the compliance film 18d1 and the fixing plate 14, partitioned by the frame 18d2. Compliance space Rca is separated from the liquid storage chamber Ra via the compliance film 18d1 and is a space that allows deformation of the compliance film 18d1 in response to pressure changes of the ink in the liquid storage chamber Ra. Compliance space Rcb is separated from the liquid storage chamber Rb via the compliance film 18d1 and is a space that allows deformation of the compliance film 18d1 in response to pressure changes of the ink in the liquid storage chamber Rb.

[0063] Although not shown in the diagram, a wiring board for electrically connecting the control unit 20 and the head chip HC is mounted on the surface of the diaphragm 18e facing the Z1 direction. This wiring board is, for example, a COF (Chip On Film), FPC (Flexible Printed Circuit), or FFC (Flexible Flat Cable) substrate, and a drive circuit for supplying drive voltage to each drive element Ea and Eb is mounted on this wiring board. This drive circuit is a circuit that switches whether or not to supply at least a part of the waveform included in the drive signal D as a drive pulse based on the control signal S.

[0064] As described above, the head tip HC is housed in the recess 13c of the holder 13 and fixed to the holder 13 by a fixing plate 14 via a reinforcing plate 15. Here, the fixing plate 14 has an inner circumferential surface F4 that defines the opening 14a, as shown in Figure 6 below. On the other hand, the nozzle plate 18c has an outer circumferential surface F3 that is positioned inside the inner circumferential surface F4, as shown in Figure 6 below. The gap between the outer circumferential surface F3 of the nozzle plate 18c and the inner circumferential surface F4 of the opening 14a is filled with a sealing material 81. The sealing material 81 is an example of the "first sealing material" when either the nozzle plate 18c or the fixing plate 14 is considered an example of the "first member" and the other is considered an example of the "second member".

[0065] Furthermore, the fixing plate 14 is placed in the recess 13c while overlapping the reinforcing plate 15. That is, as shown in Figure 8 described later, the outer surface F5 is positioned inside the inner surface F6 of the recess 13c. The gap between the outer surface F5 of the fixing plate 14 and the inner surface F6 of the recess 13c is filled with sealing material 82. The sealing material 82 is an example of the "first sealing material" when either the fixing plate 14 or the holder 13 is considered an example of the "first member" and the other is considered an example of the "second member".

[0066] Figure 5 is a bottom view of the liquid injection head 1 according to the embodiment. Figure 5 shows the liquid injection head 1 as viewed in the Z1 direction. As shown in Figure 5, the sealing material 81 is provided around the entire circumference of the outer peripheral surface F3 of each nozzle plate 18c or the inner peripheral surface F4 of the opening 14a. Details of the sealing material 81 will be described later with reference to Figures 6 and 7.

[0067] Furthermore, the sealing material 82 is provided around the entire circumference of the outer circumferential surface F5 of the fixing plate 14 or the inner circumferential surface F6 of the recess 13c. Details of the sealing material 82 will be described later with reference to Figure 8.

[0068] Furthermore, a sealing material 83 is filled into the through-hole 14b of the fixing plate 14. Details of the sealing material 83 will be explained later with reference to Figure 9.

[0069] 1-4. Sealing between the fixing plate and the nozzle plate Figure 6 is an explanatory diagram of the sealing material 81 filled between the nozzle plate 18c and the fixing plate 14. Figure 7 is an explanatory diagram of the operation of the sealing material 81 shown in Figure 6. Figure 7 shows the sealing material 81 in the Z1 direction with a portion of the second layer 81b, which will be described later, missing.

[0070] As described above, the sealing material 81 is placed between the outer peripheral surface F3 of the nozzle plate 18c and the inner peripheral surface F4 of the opening 14a. Here, as described above, the liquid injection head 1 includes a compliance substrate 18d and a communication plate 18a, and neither the compliance substrate 18d nor the communication plate 18a constitutes the outer surface of the liquid injection head 1. In contrast, the nozzle plate 18c and the fixing plate 14 constitute the outer surface of the liquid injection head 1. The sealing material 81 is made of an adhesive such as an epoxy adhesive.

[0071] Furthermore, the compliance substrate 18d and the fixing plate 14 are joined to each other via an adhesive layer 91. The compliance substrate 18d and the communication plate 18a are joined to each other via an adhesive layer 92. The communication plate 18a and the nozzle plate 18c are joined to each other via an adhesive layer 93. Each of the adhesive layers 91, 92, and 93 is a layer composed of an adhesive such as an epoxy adhesive or a silicone adhesive, and is not exposed to the outside of the liquid spray head 1. Here, adhesive layer 91 is an example of a "second sealing material" and is filled in the gap between the compliance substrate 18d and the fixing plate 4. Adhesive layer 92 is an example of a "second sealing material" and is filled in the gap between the compliance substrate 18d and the communication plate 18a. Adhesive layer 93 is an example of a "second sealing material" and is filled in the gap between the communication plate 18a and the nozzle plate 18c. In this way, the liquid spray head 1 is equipped with adhesive layers 91, 92, and 93.

[0072] The sealing material 81 is particularly close to the nozzle N and is therefore prone to swelling or dissolution due to the adhesion of ink mist. Furthermore, when a wiping member 70 is used as in this embodiment, the sealing material 81 comes into contact with the ink during cleaning or wiping with the wiping member 70, which also makes the sealing material 81 prone to swelling or dissolution. In addition, the surface of the sealing material 81 may be scraped off due to contact with the wiping member 70, and in this case, if the adhesive layer 91 between the fixing plate 14 and the compliance substrate 18d is exposed to the outside, there is a risk that the adhesive layer 91 will swell or dissolve due to contact with the ink, resulting in poor adhesion. If such poor adhesion occurs, the compliance substrate 18d will not be able to perform its role, which may adversely affect ink ejection. Also, in this case, if the adhesive layers 92 and 93 are exposed to the outside, there is a risk that the adhesive layers 92 and 93 will also suffer from poor adhesion due to swelling or dissolution due to contact with the ink, which may adversely affect ink ejection. It is necessary to be able to detect when the sealing material 81 has reached a state where it is prone to sealing defects before such a malfunction occurs.

[0073] Therefore, the sealing material 81 has a first layer 81a and a second layer 81b. These are stacked in the order of the first layer 81a and the second layer 81b from the inside to the outside of the liquid injection head 1.

[0074] Here, the first layer 81a is covered by the second layer 81b and is not exposed to the outside of the liquid spray head 1. On the other hand, the second layer 81b is exposed to the outside of the liquid spray head 1. The colors of the first layer 81a and the second layer 81b are different from each other.

[0075] Thus, since the first layer 81a is covered by the second layer 81b, and the second layer 81b is exposed to the outside of the liquid spray head 1, if the sealing material 81 is damaged due to swelling or dissolution caused by contact with ink, or due to external force, the second layer 81b will be damaged before the first layer 81a. When at least a portion of the second layer 81b in the circumferential direction is damaged over its entire thickness, the first layer 81a is exposed at the damaged area CR, as shown in Figure 7. At this time, since the colors of the first layer 81a and the second layer 81b are different, it is possible to detect that the second layer 81b has been damaged at the exposed area CR of the first layer 81a. Therefore, it is possible to detect that the first layer 81a is about to be damaged, dissolved, or chipped before any malfunction occurs in the liquid spray head 1 due to peeling caused by swelling, dissolution, or abrasion of the first layer 81a. In the following, the state in which "the first layer 81a is about to be scraped, dissolved, or chipped" is referred to as "the near end of the first layer 81a."

[0076] Here, "different colors" means that when visible light or ultraviolet light is irradiated onto the liquid spray head 1, at least one difference among hue, lightness, and saturation can be visually distinguished.

[0077] More specifically, the color difference between the color of the first layer 81a and the color of the second layer 81b is preferably 12.0 or greater, and more preferably 25 or greater. This allows the difference between the color of the first layer 81a and the color of the second layer 81b to be easily determined by visual inspection. This color difference is, for example, defined by CIE1976 L * a * B * This is the color difference within a color system. The measurement of this color difference is performed, for example, in accordance with JIS Z8730.

[0078] The colors of the first layer 81a and the second layer 81b may be chromatic or achromatic. A chromatic color is a color that has hue, saturation, and lightness. Specific examples of chromatic colors are not limited to JIS safety colors (red, reddish-yellow, yellow, green, blue, reddish-purple), etc. Achromatic colors are colors that lack both hue and saturation. Specific examples of achromatic colors are not limited to JIS safety colors (white, black), etc.

[0079] However, if one of the first layer 81a and the second layer 81b is a chromatic color and the other is achromatic, the chromatic color will stand out while the achromatic color will not, making it easier to distinguish between the colors of the first layer 81a and the second layer 81b. From the viewpoint that it is easier to detect that the first layer is exposed if the color of area CR, where the first layer 81a is exposed, is more noticeable than the color of the area where the first layer 81a is not exposed but the second layer 81b is exposed, it is preferable that the color of the first layer 81a is chromatic and the color of the second layer 81b is achromatic.

[0080] Each of the first layer 81a and the second layer 81b is composed of a resin composition containing a thermosetting resin, such as an epoxy resin. However, the composition of the resin composition constituting the first layer 81a and the composition of the resin composition constituting the second layer 81b are different from each other, such that the colors of the first layer 81a and the second layer 81b are different. The resin composition may contain inorganic fillers such as silica or alumina, or other additives.

[0081] The resin composition constituting the first layer 81a and the resin composition constituting the second layer 81b, or both, may contain a coloring agent as needed. If at least one of the first layer 81a and the second layer 81b contains a coloring agent, the degree of difference between the color of the first layer 81a and the color of the second layer 81b can be easily adjusted depending on the type or amount of coloring agent.

[0082] Colorants are not particularly limited, but examples include various pigments and various dyes.

[0083] Examples of pigments include CI Pigment Red 2, 3, 5, 17, 22, 23, 38, 81, 48:1, 48:2, 48:3, 48:4, 49:1, 52:1, 53:1, 57:1, 63:1, 112, 122, 144, 146, 149, 166, 170, 176, 177, 178, 179, 185, 202. ,207,209,254,101,102,105,106,108,108:1, CI Pigment Green 7,36,15,17,18,19,26,50, CI Pigment Blue 1,15,15:1,15:2,15:3,15:4,15:6,17:1,18,60,27,28,29,35,36 Examples include CI Pigment Yellow 1,3,12,13,14,17,55,73,74,81,83,93,94,95,97,108,109,110,129,138,139,150,151,153,154,168,184,185,34,35,35:1,37,37:1,42,43,53,157, CI Pigment Violet 1,3,19,23,50,14,16, CI Pigment Orange 5,13,16,36,43,20,20:1,104, CI Pigment Brown 25,7,11,33, etc., and one of these can be used alone or in combination of two or more.

[0084] Examples of dyes include azo dyes, anthraquinone dyes, condensed polycyclic aromatic carbonyl dyes, indigoid dyes, carbonium dyes, phthalocyanine dyes, methine, and polymethine dyes. Specific examples of dyes include CI Direct Red 2, 4, 9, 23, 26, 28, 31, 39, 62, 63, 72, 75, 76, 79, 80, 81, 83, 84, 89, 92, 95, 111, 173, 184, 207, 211, 2 12,214,218,221,223,224,225,226,227,232,233,240,241,242,243,247, CI Acid Red 35,42,51,52,57,62,80,82,111,114,118,119,127,128,131,143,145,151,154,157,158,211,249,254,257,261,263,266,289,299,301,305,319,336,337,361,396,397, CI Reactive Red 3,13,17,19, 21,22,23,24,29,35,37,40,41,43,45,49,55, CI Basic Red 12,13,14,15,18,22,23,24,25,27,29,35,36,38,39,45,46, CI Direct Violet 7,9,47,48,51,66,90,93,94,95,98,100,101, CI Acid Violet 5,9,11,34,43,47,48,51,75,90,103,126, CI Reactive Violet 1,3,4,5,6,7,8,9,16,17,22, 23,24,26,27,33,34, CI Basic Violet 1,2,3,7,10,15,16,20,21,25,27,28,35,37,39,40,48, CI Direct Yellow 8,9,11,12,27,28,29,33,35,39,41,44,50,53,58,59,68,87,93,95,96,98,100,106,108,109,110,130,142,144,161,163, CI Acid Yellow 17,19,23,25,39,40,42,44,49,50,61,64, 76, 79, 110, 127, 135, 143, 151, 159, 169, 174, 190, 195, 196, 197, 199, 218, 219, 222, 227, CI Reactive Yellow 2, 3, 13, 14, 15, 17, 18, 23, 24, 25, 26, 27, 29, 35, 37, 41, 42, CI Basic Yellow 1, 2, 4, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 39, 40, CI Acid Green 16, CI Acid Blue 9, 45, 80, 83, 90, 185, CIExamples include Basic Orange 21 and 23, and these can be used individually or in combination of two or more.

[0085] The amount of coloring agent in the first layer 81a or the second layer 81b is not particularly limited, as long as it does not cause curing defects in the sealant 81.

[0086] When both the first layer 81a and the second layer 81b contain a coloring agent, it is preferable that the color of the coloring agent in the first layer 81a and the color of the coloring agent in the second layer 81b are different from each other. This makes it possible to make the colors of the first layer 81a and the second layer 81b different. In this case, the second layer 81b may be colored translucent. Colored translucent means that the second layer 81b is colored, but the first layer 81a is visible through it. However, from the viewpoint of making defects in the second layer 81b easier to see, it is preferable that the second layer 81b is opaque.

[0087] When the second layer 81b does not contain a coloring agent and the first layer 81a contains a coloring agent, it is preferable that the second layer 81b be opaque in order to make the defects in the second layer 81b easier to see.

[0088] If the first layer 81a does not contain a coloring agent and the second layer 81b contains a coloring agent, the second layer 81b may be colored and semi-transparent, but it is preferable that it be opaque from the viewpoint of making defects in the second layer 81b easier to see.

[0089] If both the first layer 81a and the second layer 81b do not contain colorants, it is preferable that the types of encapsulants constituting the first layer 81a and the second layer 81b are different. This makes it possible to make the colors of the first layer 81a and the second layer 81b different. In this case, it is preferable that the second layer 81b is opaque in order to make any defects in the second layer 81b more visible.

[0090] When both the first layer 81a and the second layer 81b contain a coloring agent, it is preferable that the color of the coloring agent in the first layer 81a and the color of the coloring agent in the second layer 81b are different from each other. This makes it easy to adjust the difference between the color of the first layer 81a and the color of the second layer 81b depending on the type or amount of coloring agent used in the first layer 81a and the second layer 81b.

[0091] It is preferable that the components of the first layer 81a, excluding the coloring agent, and the components of the second layer 81b, excluding the coloring agent, are the same. For example, it is preferable that the resin components contained in the first layer 81a and the resin components contained in the second layer 81b are the same, and when a filler is used, it is preferable that the type and content of the filler contained in the first layer 81a and the type and content of the filler contained in the second layer 81b are the same. This makes it possible to substantially eliminate the difference in the coefficient of linear expansion between the first layer 81a and the second layer 81b. As a result, it is possible to reduce the peeling of the sealing material 81 caused by the difference in the coefficient of linear expansion. On the other hand, the larger the difference in the coefficient of linear expansion, the larger the difference in the amount of shrinkage due to curing between the first layer 81a and the second layer 81b, so the sealing material 81 becomes more prone to peeling due to warping caused by the stress difference between the first layer 81a and the second layer 81b.

[0092] The coloring agent is preferably a dye. Since dye particles are smaller than pigment particles, the adverse effects of coloring agent particles can be reduced compared to when pigments are used. These adverse effects include, for example, damage to the wiping member 70 due to the adhesion of coloring agent particles, damage to the nozzle plate 18c due to coloring agent particles interposed between the wiping member 70 and the nozzle plate 18c, and spray failure due to coloring agent particles remaining in the nozzle N. The coloring agent is not limited to dyes and may also be a pigment.

[0093] When at least one of the first layer 81a and the second layer 81b contains a phosphor that emits light upon ultraviolet irradiation as a coloring agent, irradiating the encapsulant 81 with ultraviolet light can cause one or both of the first layer 81a and the second layer 81b to emit light. In this case, the difference between the color of the first layer 81a and the color of the second layer 81b can be determined based on the presence or absence of light emission or the difference in the color of the emitted light between the first layer 81a and the second layer 81b.

[0094] Phosphors are, for example, fluorescent pigments or fluorescent dyes, specifically CI Disperse Red 364, CI Disperse Red 362, CI Batt Red 41, CI Disperse Yellow 232, CI Disperse Yellow 184, CI Disperse Yellow 82, CI Disperse Yellow 43, and the like.

[0095] Looking in the Z1 direction, which is the opposite direction to the Z2 direction (an example of the "first direction"), the first layer 81a is positioned between the surface F1 of the nozzle plate 18c and the surface F2 of the fixing plate 14. As a result, as shown in Figure 7, the first layer 81a is visible when viewed in the opposite direction to the Z2 direction, making it easy to detect the near end of the first layer 81a.

[0096] Similarly, when viewed in the opposite direction of Z2, the second layer 81b is also positioned between surfaces F1 and F2. This allows for visual identification of areas of the first layer 81a exposed due to defects in the second layer 81b when viewed in the opposite direction of Z2.

[0097] Furthermore, the first layer 81a is positioned between the outer surface F3 and the inner surface F4. As a result, the first layer 81a is visible when viewed in the Z1 direction, which is along the central axis of the opening 14a of the fixing plate 14, making it easy to detect the near end of the first layer 81a.

[0098] Similarly, the second layer 81b is also positioned between the outer surface F3 and the inner surface F4. This allows for visual identification of the area CR, which is the exposed portion of the first layer 81a due to a defect in the second layer 81b, when viewed in the Z1 direction, which is along the central axis of the opening 14a of the fixing plate 14.

[0099] The first layer 81a is in contact with the adhesive layer 91 provided between the fixing plate 14 and the compliance substrate 18d. As a result, even if the second layer 81b peels off, the adhesive layer 91 is covered by the first layer 81a, so the peeling of the second layer 81b can be detected before the adhesive layer 91 is exposed to the outside. Therefore, problems such as spray failure caused by peeling of the adhesive layer 91 due to ink adhesion can be prevented.

[0100] Similarly, the first layer 81a is in contact with the adhesive layer 93 provided between the nozzle plate 18c and the communication plate 18a. As a result, even if the second layer 81b peels off, the adhesive layer 93 is covered by the first layer 81a, so the peeling of the second layer 81b can be detected before the adhesive layer 93 is exposed to the outside. Therefore, problems such as spray failure caused by peeling of the adhesive layer 93 due to ink adhesion can be prevented.

[0101] Preferably, the thickness t1 of the first layer 81a at position T0 where the thickness of the sealing material 81 is smallest is greater than the thickness t2 of the second layer 81b at the same position T0. This ensures that when the sealing material 81 is scraped from the surface exposed to the outside of the second layer 81b to the boundary between the second layer 81b and the first layer 81a at position T0 where it is thinnest, more than half of the total thickness of the sealing material 81 remains. Therefore, it is possible to detect early the possibility of a defect occurring due to peeling of the first layer 81a before such a defect actually occurs.

[0102] The thickness of the sealing material 81 is the distance from the surface of the first layer 81a that is neither the interface between the first layer 81a and the second layer 81b, nor in contact with either the nozzle plate 18c or the fixing plate 14, to the surface that is exposed to the outside of the second layer 81b.

[0103] When the shortest line segment LL1 is drawn from position Pt1 where the adhesive layer 91 and the first layer 81a are in contact with each other between the compliance substrate 18d and the fixing plate 14 to the surface exposed to the outside of the second layer 81b, it is preferable that the length of the portion of the line segment LL1 that passes through the first layer 81a is greater than the length of the portion that passes through the second layer 81b. This makes it possible to detect when exposure is imminent before the adhesive layer 91 is exposed due to peeling of the first layer 81a covering the adhesive layer 91.

[0104] When the shortest line segment LL2 is drawn from the position Pt2 where the adhesive layer 93 and the first layer 81a are in contact with each other between the connecting plate 18a and the nozzle plate 18c to the surface of the second layer 81b that is exposed to the outside, it is preferable that the length of the portion of the line segment LL2 that passes through the first layer 81a is greater than the length of the portion of the line segment LL2 that passes through the second layer 81b. This makes it possible to detect when exposure is imminent before the adhesive layer 93 is exposed due to peeling of the first layer 81a that covers the adhesive layer 93.

[0105] The thickness t1 of the first layer 81a at position T0 is preferably at least twice the thickness t2 of the second layer 81b at position T0, and more preferably at least twice and less than three times the thickness t2 of the second layer 81b. This allows for early and appropriate detection of the possibility of a defect occurring due to delamination of the first layer 81a before such a defect actually occurs. The thickness t1 of the first layer 81a may be three times or more the thickness t2 of the second layer 81b. Furthermore, the length of the portion of line segment LL1 that passes through the first layer 81a is preferably at least twice the length of the portion of line segment LL1 that passes through the second layer 81b, and more preferably at least twice and less than three times the length of the portion of line segment LL1 that passes through the second layer 81b. Furthermore, the length of the portion of line segment LL2 that passes through the first layer 81a is preferably at least twice the length of the portion of line segment LL2 that passes through the second layer 81b, and more preferably at least twice and up to three times the length of the portion of line segment LL2 that passes through the second layer 81b. This also makes it possible to detect the possibility of a defect occurring due to delamination of the first layer 81a at an early and appropriate time, before such a defect actually occurs.

[0106] As described above, the sealing material 81 includes a first layer 81a and a second layer 81b. In contrast, each of the adhesive layers 91, 92, and 93 consists of only one layer. This makes it difficult to visually inspect the adhesive layers 91, 92, and 93, which are not exposed to the outside, even if they are made into a two-layer structure of different colors. By making the adhesive layers 91, 92, and 93 into only one layer, the cost required for the adhesive layers 91, 92, and 93 can be reduced. In this embodiment, the "second sealing material" is not limited to the adhesive layers 91, 92, and 93. Other application locations for the "second sealing material" include, for example, the space between the drive elements Ea and Eb and the diaphragm 18e (not shown), and the space between the wiring board mounted on the Z1-facing surface of the diaphragm 18e and the diaphragm 18e (not shown).

[0107] 1-5. Sealing between the fixing plate and the holder Figure 8 is an explanatory diagram of the sealing material 82 that is filled between the holder 13 and the fixing plate 14. The sealing material 82 is placed between the outer peripheral surface F5 of the fixing plate 14 and the inner peripheral surface F6 of the recess 13c of the holder 13. Here, as mentioned above, the liquid spray head 1 is equipped with a reinforcing plate 15, and the reinforcing plate 15 does not constitute the outer surface of the liquid spray head 1. In contrast, the fixing plate 14 and the holder 13 constitute the outer surface of the liquid spray head 1. The sealing material 82 is made of an adhesive such as an epoxy adhesive.

[0108] Furthermore, a stepped surface 13c1 facing the Z2 direction is provided on the inner circumferential surface F6 of the recess 13c, and the surface of the reinforcing plate 15 facing the Z1 direction is joined to the stepped surface 13c1 via an adhesive layer 94. The surface of the reinforcing plate 15 facing the Z2 direction is joined to the surface of the fixing plate 14 facing the Z1 direction via an adhesive layer 95. Each of the adhesive layers 94 and 95 is composed of an adhesive such as an epoxy adhesive or a silicone adhesive, and is not exposed to the outside of the liquid spray head 1.

[0109] The sealing material 82, like the sealing material 81, is particularly close to the nozzle N and is therefore prone to swelling or dissolution due to the adhesion of ink mist. Furthermore, when the wiping member 70 is used as in this embodiment, the sealing material 82 comes into contact with the ink during cleaning or wiping with the wiping member 70, which also makes the sealing material 82 prone to swelling or dissolution. In addition, the surface of the sealing material 82 may be abraded due to contact with the wiping member 70. If the sealing material 82 is abraded and the adhesive layer 94 or adhesive layer 95 is exposed to the outside, the adhesive layer 94 or adhesive layer 95 may swell or dissolve due to contact with the ink, causing poor adhesion, and eventually leading to problems such as the fixing plate 14 or reinforcing plate 15 peeling off.

[0110] Therefore, the sealing material 82 has a first layer 82a and a second layer 82b. These are stacked in the order of the first layer 82a and the second layer 82b from the inside to the outside of the liquid injection head 1.

[0111] Here, the first layer 82a is covered by the second layer 82b and is not exposed to the outside of the liquid spray head 1. On the other hand, the second layer 82b is exposed to the outside of the liquid spray head 1. The colors of the first layer 82a and the second layer 82b are different from each other. The constituent materials and relative thicknesses of the first layer 82a and the second layer 82b are the same as those of the first layer 81a and the second layer 81b of the sealing material 81 described above.

[0112] Thus, since the first layer 82a is covered by the second layer 82b, and the second layer 82b is exposed to the outside of the liquid spray head 1, if the sealing material 82 is damaged due to swelling or dissolution caused by contact with ink, or due to external force, the second layer 82b will be damaged before the first layer 82a. When the second layer 82b is damaged over its entire thickness, the first layer 82a is exposed at the damaged area. At this time, since the colors of the first layer 82a and the second layer 82b are different, it is possible to detect that the second layer 82b has been damaged at the exposed area of ​​the first layer 82a. Therefore, it is possible to detect that there is a risk of a malfunction occurring due to the first layer 82a being about to be damaged, dissolved, or chipped before a malfunction occurs due to the first layer 81a being peeled off by swelling, dissolution, or abrasion. In other words, the near end of the first layer 82a can be detected.

[0113] Looking in the Z1 direction, which is the opposite direction to the Z2 direction (an example of the "first direction"), the first layer 82a is positioned between the surface F2 of the fixing plate 14 and the surface F12 of the holder 13. As a result, as shown in Figure 5, the first layer 82a is visible when viewed in the opposite direction to the Z2 direction, making it easy to detect the near end of the first layer 82a.

[0114] Similarly, when viewed in the opposite direction of Z2, the second layer 82b is also positioned between plane F2 and plane F12. This allows for visual identification of the exposed areas of the first layer 82a due to defects in the second layer 82b when viewed in the opposite direction of Z2.

[0115] Furthermore, the first layer 82a is positioned between the outer surface F5 and the inner surface F6. Since the first layer 82a is visible when viewed in the Z1 direction, the near end of the first layer 82a can be easily detected.

[0116] Similarly, the second layer 82b is also positioned between the outer surface F5 and the inner surface F6. This allows for visual identification of areas of the first layer 82a exposed due to defects in the second layer 82b when viewed in the Z1 direction.

[0117] The first layer 82a is in contact with the adhesive layer 95 provided between the reinforcing plate 15 and the fixing plate 14. As a result, even if the second layer 82b peels off, the adhesive layer 95 is covered by the first layer 82a, so the peeling of the second layer 82b can be detected before the adhesive layer 95 is exposed to the outside. Therefore, problems such as spray failure caused by peeling of the adhesive layer 95 due to ink adhesion can be prevented.

[0118] 1-6. Sealing of through holes in the fixing plate Figure 9 is an explanatory diagram of the sealing material 83 that fills the through-hole 14b of the fixing plate 14 and the through-hole 15b of the reinforcing plate 15. The through-holes 14b and 15b are connected to each other so as to be continuous, and the sealing material 83 is filled into the through-hole formed by these through-holes. Here, the surface F2 of the fixing plate 14 facing in the Z2 direction constitutes the outer surface of the liquid injection head 1. The sealing material 83 is made of an adhesive such as an epoxy adhesive.

[0119] The sealing material 83, like the sealing materials 81 and 82, is close to the nozzle N and is therefore prone to swelling or dissolution due to the adhesion of ink mist. Furthermore, when the wiping member 70 is used as in this embodiment, the sealing material 83 comes into contact with the ink during cleaning or wiping with the wiping member 70, which also makes the sealing material 82 prone to swelling or dissolution. In addition, the surface of the sealing material 83 may be abraded due to contact with the wiping member 70. If the sealing material 83 is abraded and the adhesive layer 94, which is placed between the holder 13 and the reinforcing plate 15, is exposed to the outside, the adhesive layer 94 may swell or dissolve due to contact with the ink, causing poor adhesion, and eventually leading to problems such as the reinforcing plate 15 peeling off.

[0120] The sealing material 83 has a first layer 83a and a second layer 83b. These are stacked in the order of the first layer 83a and the second layer 83b from the inside to the outside of the liquid injection head 1.

[0121] Here, the first layer 83a is covered by the second layer 83b and is not exposed to the outside of the liquid spray head 1. On the other hand, the second layer 83b is exposed to the outside of the liquid spray head 1. The colors of the first layer 83a and the second layer 83b are different from each other. The constituent materials and relative thicknesses of the first layer 83a and the second layer 83b are the same as those of the first layer 81a and the second layer 81b of the sealing material 81 described above.

[0122] Thus, since the first layer 83a is covered by the second layer 83b, and the second layer 83b is exposed to the outside of the liquid spray head 1, if the sealing material 83 is damaged due to swelling or dissolution caused by contact with ink, or due to external force, the second layer 83b will be damaged before the first layer 83a. When the second layer 83b is damaged over its entire thickness, the first layer 83a is exposed at the damaged area. At this time, since the colors of the first layer 83a and the second layer 83b are different, it is possible to detect that the second layer 83b has been damaged at the exposed area of ​​the first layer 83a. Therefore, it is possible to detect that there is a risk of a malfunction occurring because the first layer 83a is about to be damaged, dissolved, or chipped, before a malfunction occurs due to the first layer 81a being peeled off by swelling, dissolution, or abrasion. In other words, the near end of the first layer 83a can be detected.

[0123] 1-7. Sealing between the holder and the cover Figure 10 is a side view of the liquid spray head 1 according to the embodiment. Figure 11 is an explanatory diagram of the sealing material 84 filled between the cover 16 and the holder 13. The sealing material 84 is filled into the gap between surface F9, which is the outer circumferential surface of the cover 16, and surface F8, which is the outer circumferential surface of the holder 13, when viewed in a direction intersecting the Z axis. The sealing material 84 is made of an adhesive such as an epoxy adhesive or a silicone adhesive.

[0124] If the sealing material 84 dissolves and disappears due to swelling caused by the ink mist, poor adhesion may occur between the holder 13 and the cover 16, potentially causing ink to adhere to electronic components inside the cover 16, such as a circuit board 12, and leading to malfunction.

[0125] Therefore, the sealing material 84 has a first layer 84a and a second layer 84b. These are stacked in the order of the first layer 84a and the second layer 84b, from the inside to the outside of the liquid injection head 1 in a direction intersecting the Z axis.

[0126] Here, the first layer 84a is covered by the second layer 84b and is not exposed to the outside of the liquid injection head 1. On the other hand, the second layer 84b is exposed to the outside of the liquid injection head 1. The colors of the first layer 84a and the second layer 84b are different from each other. The constituent materials and relative thicknesses of the first layer 84a and the second layer 84b are the same as those of the first layer 81a and the second layer 81b of the sealing material 81 described above.

[0127] Thus, since the first layer 84a is covered by the second layer 84b, and the second layer 84b is exposed to the outside of the liquid spray head 1, if the sealing material 84 is damaged due to swelling or dissolution caused by contact with ink, or due to external force, the second layer 84b will be damaged before the first layer 84a. When the second layer 84b is damaged over its entire thickness, the first layer 84a is exposed at the damaged area. At this time, since the colors of the first layer 84a and the second layer 84b are different, it is possible to detect that the second layer 84b has been damaged at the exposed area of ​​the first layer 84a. Therefore, it is possible to detect that the first layer 84a is about to be damaged, dissolved, or chipped before any malfunction occurs in the liquid spray head 1 due to peeling caused by the first layer 81a swelling, dissolving, or being scraped off. In other words, the near end of the first layer 81a can be detected.

[0128] As an example of the "first direction," when viewed in a direction intersecting the Z-axis, the first layer 84a is positioned between surface F9, which is the outer circumferential surface of the cover 16, and surface F8, which is the outer circumferential surface of the holder 13. As a result, as shown in Figure 10, when viewed in a direction intersecting the Z-axis, the first layer 84a is in a visible position, making it easy to detect the near end of the first layer 84a.

[0129] Similarly, when viewed in the direction intersecting the Z-axis, the second layer 84b is also positioned between planes F9 and F8. This allows for visual identification of areas of the first layer 84a that are exposed due to defects in the second layer 84b when viewed in the direction intersecting the Z-axis.

[0130] 1-8. Sealing between the cover and the flow channel Figure 12 is an explanatory diagram of the cover 16 and the flow channel tube 11b. Figure 13 is an explanatory diagram of the sealing material 85 that is filled between the cover 16 and the flow channel tube 11b. As described above, the liquid injection head 1 comprises a flow channel member 11a, a flow channel tube 11b, and a cover 16. Here, the sealing material 85 is filled in the gap between the outer circumferential surface F10 of the flow channel tube 11b and the inner circumferential surface F11 of the opening 16a of the cover 16. The sealing material 85 is made of an adhesive such as an epoxy adhesive or a silicone adhesive.

[0131] The sealing material 85 that seals the space between the flow channel 11b and the opening 16a dissolves and disappears due to swelling caused by ink dripping from the flow channel 11b, resulting in poor adhesion between the flow channel 11b and the cover 16. Furthermore, if the sealing material 85 is scraped away and ink penetrates into the cover 16, there is a risk that the ink will adhere to electronic components inside the cover 16, such as a circuit board 12, and cause malfunctions.

[0132] Therefore, the sealing material 85 has a first layer 85a and a second layer 85b. These are stacked in the order of the first layer 85a and the second layer 85b, from the inside to the outside of the liquid injection head 1 in a direction along the Z axis.

[0133] Here, the first layer 85a is covered by the second layer 85b and is not exposed to the outside of the liquid spray head 1. On the other hand, the second layer 85b is exposed to the outside of the liquid spray head 1. The colors of the first layer 85a and the second layer 85b are different from each other. The constituent materials and relative thicknesses of the first layer 85a and the second layer 85b are the same as those of the first layer 81a and the second layer 81b of the sealing material 81 described above.

[0134] With such a sealing material 85, it is possible to detect when the second layer 85b is scraped off while the first layer 85a remains intact, before the aforementioned adverse effects occur, thus enabling the detection of the near end of the first layer 85a.

[0135] Looking in the Z2 direction, which is the opposite direction to the Z1 direction (an example of the "first direction"), the first layer 85a is positioned between the surface F14 of the cover 16 and the surface F13 of the flow channel 11b. As a result, as shown in Figure 12, the first layer 85a is visible when viewed in the Z2 direction, making it easy to detect the near end of the first layer 85a.

[0136] Similarly, when viewed in the Z2 direction, which is the opposite direction to the Z1 direction, the second layer 85b is also positioned between surfaces F14 and F13. This allows for visual identification of the exposed areas of the first layer 85a due to defects in the second layer 85b when viewed in the Z2 direction.

[0137] Furthermore, the first layer 85a is positioned between the outer surface F10 and the inner surface F11. As a result, the first layer 85a is visible when viewed in the Z2 direction, making it easy to detect the near end of the first layer 85a.

[0138] Similarly, the second layer 85b is also positioned between the outer surface F10 and the inner surface F11. This allows for visual identification of areas of the first layer 85a that are exposed due to defects in the second layer 85b when viewed in the Z2 direction.

[0139] 2. Variations The forms exemplified above can be modified in various ways. Specific examples of modifications that can be applied to the aforementioned forms are given below. Two or more forms arbitrarily selected from the following examples can be merged as appropriate, provided they do not contradict each other.

[0140] 2-1. Variation 1 In the above-described embodiment, each of the sealing materials 81, 82, 83, 84, and 85 is exemplified as having a two-layer laminated structure. However, the embodiment is not limited to this, and at least one of the sealing materials 81, 82, 83, 84, and 85 may have a three-layer laminated structure. For example, the sealing material 81 may include a third layer positioned between the first layer 81a and the second layer 81b, in addition to the first layer 81a and the second layer 81b. In this case, it is preferable that the color of the third layer is different from the color of either the first layer 81a or the second layer 81b. This makes it possible to detect the lifespan of the sealing material 81 in multiple stages.

[0141] 2-2. Variation 2 In the above-described embodiment, an example was given in which the sealing material 81 has a first layer 81a and a second layer 81b over the entire circumference of the gap between the outer peripheral surface F3 of the nozzle plate 18c and the inner peripheral surface F4 of the opening 14a of the fixing plate 14 when viewed in the Z1 direction. However, the embodiment is not limited to this, and the sealing material 81 may have a first layer 81a and a second layer 81b over only a part of the gap between the outer peripheral surface F3 of the nozzle plate 18c and the inner peripheral surface F4 of the opening 14a. Similarly, the sealing material 82 may have a first layer 82a and a second layer 82b over only a part of the gap between the outer peripheral surface F5 of the fixing plate 14 and the inner peripheral surface F6 of the recess 13c of the holder 13 when viewed in the Z1 direction. Furthermore, the sealing material 84 may have a first layer 84a and a second layer 84b over only a part of the gap between the outer peripheral surface F9 of the cover 16 and the outer peripheral surface F8 of the holder 13 when viewed in the direction intersecting the Z axis. Furthermore, when viewed in the Z2 direction, the sealing material 85 may have a first layer 85a and a second layer 85b only in a portion of the gap between the outer circumferential surface F10 of the flow channel pipe 11b and the inner circumferential surface F11 of the opening 16a of the cover 16.

[0142] 2-3. Variation 3 In the embodiments described above, a configuration in which the liquid spray head has four head tips is exemplified. However, the configuration does not have to be this configuration, and the number of head tips in the liquid spray head may be three or fewer, or five or more. Furthermore, when the liquid spray head has multiple head tips, the arrangement of these multiple head tips is not limited to the embodiments described above and is arbitrary. Also, the shape of the liquid spray head is not limited to the embodiments described above and is arbitrary.

[0143] 2-4. Variation 4 In the above-described embodiment, a serial liquid injection device 100 was illustrated in which a transporter 41 equipped with a liquid injection head 1 is reciprocated in the width direction of the medium M. However, the liquid injection device may also be a line type in which a plurality of nozzles N are distributed across the entire width of the medium M.

[0144] 2-5. Variation 5 The liquid spraying devices exemplified in the above-described form can be used in various devices such as facsimile machines and photocopiers, in addition to equipment dedicated to printing. However, the applications of liquid spraying devices are not limited to printing. For example, liquid spraying devices that spray colorant solutions are used as manufacturing equipment to form color filters for display devices such as liquid crystal display panels. Liquid spraying devices that spray conductive material solutions are used as manufacturing equipment to form wiring and electrodes on wiring boards. Furthermore, liquid spraying devices that spray solutions of organic substances related to living organisms are used, for example, as manufacturing equipment to produce biochips.

[0145] 3. Addendum A summary of this disclosure is provided below.

[0146] (Note 1) A first embodiment of a preferred example of a liquid spray head of the present disclosure is a liquid spray head comprising: a first member; a second member; and a first sealing material filled between the first member and the second member, wherein the first sealing material has a second layer exposed to the outside of the liquid spray head and a first layer covered by the second layer and not exposed to the outside of the liquid spray head, and the colors of the first layer and the second layer are different from each other.

[0147] In the above embodiment, the first layer is covered by the second layer, and the second layer is exposed to the outside of the liquid spray head. Therefore, if the first sealant is damaged due to swelling or dissolution caused by contact with ink, or due to external force, the second layer will be damaged before the first layer. When the second layer is damaged over its entire thickness, the first layer is exposed at the damaged area. At this time, since the colors of the first layer and the second layer are different, it is possible to detect that the second layer is damaged at the exposed area of ​​the first layer. Therefore, it is possible to detect that the first layer is about to be damaged, dissolved, or chipped before any malfunction occurs in the liquid spray head due to peeling caused by the first layer swelling, dissolving, or being scraped off. In other words, the near end of the first layer can be detected.

[0148] (Note 2) In a second embodiment, which is a preferred example of the first embodiment, the first member has a first surface facing a first direction, the second member has a second surface facing the first direction, and when viewed in the opposite direction to the first direction, the first layer is positioned between the first surface and the second surface. In this embodiment, when viewed in the opposite direction to the first direction, the first layer is in a position where it can be visually observed, so the near end of the first layer can be easily detected.

[0149] (Note 3) In a third embodiment which is a preferred example of the first or second embodiment, the second member has an inner circumferential surface defining an opening, the first member has an outer circumferential surface positioned inward from the inner circumferential surface, and the first layer is positioned between the outer circumferential surface and the inner circumferential surface. In the above embodiment, the first layer is visible when viewed in the direction along the central axis of the opening of the second member, so the near end of the first layer can be easily detected.

[0150] (Note 4) In a fourth embodiment, which is a preferred example of any of the first to third embodiments, a third member is further provided that does not constitute the outer surface of the liquid spray head, the first member and the second member constitute the outer surface of the liquid spray head, and the first layer is in contact with an adhesive layer provided between the first member and the third member. In the above embodiments, even if the second layer peels off, the adhesive layer is covered by the first layer, so it is possible to tell that the second layer has peeled off before the adhesive layer is exposed to the outside. This makes it possible to prevent problems such as spray failure caused by peeling of the adhesive layer due to ink adhesion.

[0151] (Note 5) In a fifth embodiment, which is a preferred example of any of the first to fourth embodiments, a second sealing material is further provided, which fills the gap and whose outer surface is not exposed to the outside of the liquid spray head, and the second sealing material is composed of only one layer. In the above embodiments, even if the second sealing material that is not exposed to the outside is made of two layers of different colors, it is not easy to inspect it by visual inspection, so by making the second sealing material a single layer, the cost required for the second sealing material can be reduced.

[0152] (Note 6) In the sixth embodiment, which is a preferred example of any of the first to fifth embodiments, the thickness of the first layer at the position where the thickness of the first sealant is smallest is greater than the thickness of the second layer at that position. In the above embodiments, when the first sealant is scraped from the surface exposed to the outside of the second layer to the boundary between the second layer and the first layer at the position where it is thinnest, more than half of the total thickness of the first sealant remains. Therefore, it is possible to detect early on the possibility of a defect occurring due to peeling of the first layer before such a defect occurs.

[0153] (Note 7) In the seventh embodiment, which is a preferred example of the sixth embodiment, the thickness of the first layer is twice or more the thickness of the second layer. In the above embodiments, it is possible to detect the possibility of a defect occurring due to peeling of the first layer at an early and appropriate time before such a defect occurs.

[0154] (Note 8) In the eighth embodiment, which is a preferred example of any of the first to seventh embodiments, at least one of the first layer and the second layer contains a coloring agent. In the above embodiments, the degree of difference between the color of the first layer and the color of the second layer can be easily adjusted depending on the type or content of the coloring agent.

[0155] (Note 9) In the ninth embodiment, which is a preferred example of the eighth embodiment, the first layer and the second layer each contain a coloring agent, and the color of the coloring agent contained in the first layer and the color of the coloring agent contained in the second layer are different from each other. In the above embodiments, the difference between the color of the first layer and the color of the second layer can be easily adjusted depending on the type or amount of coloring agent used in the first and second layers.

[0156] (Note 10) In the tenth embodiment, which is a preferred example of the eighth embodiment, the components of the first layer excluding the colorant and the components of the second layer excluding the colorant are the same. In the above embodiment, the difference in the coefficient of linear expansion between the first layer and the second layer can be substantially eliminated. Therefore, the peeling of the first sealant caused by the difference in the coefficient of linear expansion can be reduced. On the other hand, the larger the difference in the coefficient of linear expansion, the larger the difference in the amount of shrinkage due to hardening between the first layer and the second layer becomes, so the first sealant becomes more prone to peeling due to warping caused by the stress difference between the first layer and the second layer.

[0157] (Note 11) In the 11th embodiment, which is a preferred example of the 8th embodiment, the coloring agent is a dye. In the above embodiments, since the dye particles are smaller than the pigment particles, the adverse effects of the coloring agent particles can be reduced compared to when a pigment is used. Such adverse effects include, for example, damage to the wiping member due to the adhesion of coloring agent particles, damage to the nozzle plate due to coloring agent particles interposed between the wiping member and the nozzle plate, and spray failure due to coloring agent particles remaining in the nozzle.

[0158] (Note 12) In the twelfth embodiment, which is a preferred example of any of the first to eleventh embodiments, at least one of the first layer and the second layer contains a phosphor that emits light upon ultraviolet irradiation. In the above embodiments, by irradiating the first encapsulant with ultraviolet light, one or both of the first and second layers can be made to emit light. At this time, the difference between the color of the first layer and the color of the second layer can be determined based on the presence or absence of light emission or the difference in the color of the emitted light between the first and second layers.

[0159] (Note 13) In the 13th embodiment, which is a preferred example of any of the 1st to 12th embodiments, the color difference between the color of the first layer and the color of the second layer is 12.0 or more. In the above embodiments, the difference between the color of the first layer and the color of the second layer can be easily determined by visual inspection.

[0160] (Note 14) In the 14th embodiment, which is a preferred example of any of the 1st to 13th embodiments, one of the colors of the 1st layer and the 2nd layer is chromatic, and the other is achromatic. In this embodiment, the chromatic color is conspicuous, while the achromatic color is not, making it easy to distinguish between the color of the 1st layer and the color of the 2nd layer.

[0161] (Note 15) In the 15th embodiment, which is a preferred example of any of the 1st to 14th embodiments, the device comprises a nozzle plate including a nozzle for spraying liquid in the spraying direction, and a fixing plate having an opening for exposing the nozzle, wherein the first member is the nozzle plate, the second member is the fixing plate, and the first sealing material is disposed between the outer circumferential surface of the nozzle plate and the opening.

[0162] In the above embodiment, the first sealant, which is filled between the nozzle plate and the fixed plate, is located near the nozzle and is therefore prone to swelling due to the adhesion of ink mist. Furthermore, since the surface of the first sealant in the direction of ink ejection is wiped by the wiping member, the first sealant is prone to being rubbed and abraded by the wiping member. When the sealant filled between the nozzle plate and the fixed plate is abraded, the adhesive between the fixed plate and the head tip is exposed, and there is a risk that the adhesive will swell upon contact with the ink, causing poor adhesion. Such poor adhesion can prevent the compliance substrate from performing its role and may adversely affect ink ejection. Also, if the adhesive between the nozzle plate and the communication plate is exposed and the adhesive comes into contact with the ink, this may also adversely affect ink ejection. Before such adverse effects occur, it is possible to detect when the second layer has been abraded while the first layer remains intact, thus enabling the detection of the near end of the first layer of the first sealant.

[0163] (Note 16) In the 16th embodiment, which is a preferred example of any of the 1st to 14th embodiments, the device comprises a flow path member having a flow path communicating with a nozzle, a flow path tube connecting the outside of the liquid injection head to the flow path, and a cover having an opening into which the flow path tube is inserted and which houses the flow path member, wherein the first member is the flow path tube, the second member is the cover, and the first sealing material is disposed between the outer circumferential surface of the flow path tube and the opening.

[0164] In the above embodiment, the sealing material that seals the space between the flow channel and the opening of the cover dissolves and disappears due to swelling caused by ink dripping from the flow channel, resulting in poor adhesion between the flow channel and the cover. Furthermore, if the sealing material is scraped away and ink penetrates into the inside of the cover, there is a risk that the ink will adhere to electronic components such as circuit boards inside the cover and cause malfunctions. Before such adverse effects occur, it is possible to detect when the second layer has been scraped away while the first layer remains intact, thus enabling the near-end of the first layer of the first sealing material to be detected.

[0165] (Note 17) A 17th embodiment, which is a preferred example of a liquid spray head of the present disclosure, is a liquid spray head comprising: a first member having a through hole; and a first sealing material filling the through hole, wherein the first sealing material has a second layer exposed to the outside of the liquid spray head and a first layer that is covered by the second layer and not exposed to the outside of the liquid spray head, and the colors of the first layer and the second layer are different from each other.

[0166] In the above embodiment, the first layer is covered by the second layer, and the second layer is exposed to the outside of the liquid spray head. Therefore, if the first sealant is damaged due to swelling or dissolution caused by contact with ink, or due to external force, the second layer will be damaged before the first layer. When the second layer is damaged over its entire thickness, the first layer is exposed at the damaged area. At this time, since the colors of the first layer and the second layer are different, it is possible to detect that the second layer is damaged at the exposed area of ​​the first layer. Therefore, it is possible to detect that the first layer is about to be damaged, dissolved, or chipped before a malfunction occurs in the liquid spray head due to peeling of the first layer by swelling, dissolution, or abrasion. In other words, near-end damage can be detected. [Explanation of Symbols]

[0167] 1...Liquid spray head, 4...Fixing plate, 10...Liquid container, 11...Flow channel structure, 11a...Flow channel member, 11b...Flow channel tube, 12...Wiring board, 12a...Connector, 13...Holder, 13a...Holder flow channel, 13b...Wiring hole, 13c...Recess, 13c1...Stepped surface, 13d...Opening, 14...Fixing plate, 14a...Opening, 14b...Through hole, 15...Reinforcement plate, 15a...Opening, 15b...Through hole, 16...Cover, 16a...Opening, 16b...Opening, 18a...Communication plate, 18b...Pressure chamber substrate, 18c...Nozzle plate, 18d...Compliance substrate, 18d1...Comp Lynx film, 18d2…frame, 18e…diaphragm, 18g…cover, 18h…case, 18i…wiring board, 18j…drive circuit, 20…control unit, 30…transport mechanism, 40…moving mechanism, 41…transport body, 42…transport belt, 50…head module, 51…support, 51a…mounting hole, 60…circulation mechanism, 70…wiping member, 81…sealing material, 81a…first layer, 81b…second layer, 82…sealing material, 82a…first layer, 82b…second layer, 83…sealing material, 83a…first layer, 83b…second layer, 84…sealing material, 84a…first layer, 84b…second layer, 85…sealing Material, 85a...First layer, 85b...Second layer, 91...Adhesive layer, 92...Adhesive layer, 93...Adhesive layer, 94...Adhesive layer, 95...Adhesive layer, 100...Liquid injection device, CR...Location, Ca...Pressure chamber, Cb...Pressure chamber, D...Drive signal, DM...Conveying direction, Ea...Drive element, Eb...Drive element, F1...Surface, F11...Inner surface, F2...Surface, F3...Outer surface, F4...Inner surface, F5...Outer surface, F6...Inner surface, F8...Surface, F9...Surface, F10...Outer surface, F11...Inner surface, F12...Surface, F13...Surface, F14...Surface, HC...Head tip, LL1...Line segment, LL2...Line segment, La...Nozzle row, Lb...Nozzle R...row, M...medium, N...nozzle, NRa...communicating channel, NRB...communicating channel, Pt1...position, Pt2...position, R1a...space, R1b...space, R2a...space, R2b...space, RRa...supply channel, RRB...supply channel, Ra...liquid storage chamber, Ra_in...inlet, Ra_out...outlet, Rb...liquid storage chamber, Rb_in...inlet, Rb_out...outlet, Rca...compliance space, Rcb...compliance space, S...control signal, Su1...substrate, Su2...substrate, Su3...substrate, Su4...substrate, Su5...substrate, T0...position, t1...thickness, t2...thickness.

Claims

1. A liquid spray head, First member and The second member and A first sealing material is filled between the first member and the second member, Equipped with, The first sealing material is, A second layer exposed to the outside of the liquid injection head, The first layer is covered by the second layer and is not exposed to the outside of the liquid spray head, The colors of the first layer and the second layer are different from each other. A liquid spray head characterized by the following features.

2. The first member has a first surface facing a first direction, The second member has a second surface facing the first direction, Viewed in the opposite direction to the first direction, the first layer is positioned between the first surface and the second surface. The liquid spray head according to feature 1.

3. The second member has an inner circumferential surface that defines the opening, The first member has an outer circumferential surface that is positioned inside the inner circumferential surface, The first layer is disposed between the outer circumferential surface and the inner circumferential surface, The liquid spray head according to feature 1.

4. The liquid injection head further comprises a third member that does not constitute the outer surface of the liquid injection head, The first member and the second member constitute the outer surface of the liquid injection head. The first layer is in contact with the adhesive layer provided between the first member and the third member. The liquid spray head according to feature 1.

5. The system further comprises a second sealing material that fills the gap and whose outer surface is not exposed to the outside of the liquid spray head, The second sealing material consists of only one layer. The liquid spray head according to feature 1.

6. The thickness of the first layer at the position where the thickness of the first sealing material is smallest is greater than the thickness of the second layer at that position. The liquid spray head according to feature 1.

7. The thickness of the first layer is at least twice the thickness of the second layer. The liquid spray head according to feature 6.

8. At least one of the first layer and the second layer contains a coloring agent. The liquid spray head according to feature 1.

9. Each of the first and second layers contains a coloring agent, The color of the colorant contained in the first layer and the color of the colorant contained in the second layer are different from each other. The liquid spray head according to feature 8.

10. The components of the first layer excluding the coloring agent and the components of the second layer excluding the coloring agent are the same as each other. The liquid spray head according to feature 8.

11. The aforementioned coloring agent is a dye. The liquid spray head according to feature 8.

12. At least one of the first layer and the second layer includes a phosphor that emits light upon ultraviolet irradiation. The liquid spray head according to feature 1.

13. The color difference between the color of the first layer and the color of the second layer is 12.0 or greater. The liquid spray head according to feature 1.

14. Of the first and second layers, one color is chromatic, and the other color is achromatic. The liquid spray head according to feature 1.

15. A nozzle plate including a nozzle that sprays liquid in the spray direction, A fixing plate having an opening that exposes the nozzle, Equipped with, The first member is the nozzle plate, The second member is the fixing plate, The first sealing material is disposed between the outer peripheral surface of the nozzle plate and the opening. The liquid spray head according to feature 1.

16. A flow channel member having a flow channel that communicates with the nozzle, A flow channel pipe connecting the outside of the liquid injection head and the flow channel, A cover having an opening into which the flow channel pipe is inserted and housing the flow channel member, Equipped with, The first member is the flow channel tube, The second member is the cover, The first sealing material is disposed between the outer surface of the flow channel tube and the opening. The liquid spray head according to feature 1.

17. A liquid spray head, A first member having a through hole, A first sealing material is filled into the aforementioned through hole, Equipped with, The first sealing material is, A second layer exposed to the outside of the liquid injection head, The first layer is covered by the second layer and is not exposed to the outside of the liquid spray head, The colors of the first layer and the second layer are different from each other. A liquid spray head characterized by the following features.

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