Liquid ejecting head and liquid ejecting apparatus

Abstract

To provide technique capable of inhibiting intrusion of ink to the inside of a liquid ejecting head.SOLUTION: A liquid ejecting head includes: a head chip; a fixing plate having a first surface facing in an ejection direction, a second surface that is opposite from the first surface, and a lateral surface; and a holder configured to hold the head chip between itself and the fixing plate. In a plan view as seen toward the first surface, the first surface includes a water repellent region having water repellency, and a hydrophilic region that is disposed between the water repellent region and the lateral surface, and has lower water repellency than the water repellent region, and part of mold is bonded to the hydrophilic region of the first surface, the mold being disposed between the lateral surface and at least one of the head chip and the holder.SELECTED DRAWING: Figure 6

Description

Technical Field

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

Background Art

[0002] Conventionally, a liquid ejection head including a plurality of head chips each having a nozzle plate formed with a plurality of nozzles, a fixing plate to which the plurality of head chips are fixed by an adhesive, and a holder that holds the plurality of head chips between the fixing plate is known (Patent Document 1). In the conventional technology, a liquid-repellent film is formed on the surface of the fixing plate, and a plurality of exposure openings for exposing each nozzle plate to the outside are formed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional technology, a water-repellent film is formed on the surface of the fixing plate and the surface of the nozzle plate, and an adhesive as a mold is filled between the inner peripheral surface of the exposure opening of the nozzle plate and the fixing plate or between the outer peripheral surface of the fixing plate and the inner peripheral surface of the outer peripheral wall of the holder. Hereinafter, when not distinguishing between the inner peripheral surface of the exposure opening of the fixing plate and the outer peripheral surface of the fixing plate, it may be referred to as the side surface of the fixing plate. Due to the water-repellent film formed on the surface of the fixing plate and the nozzle plate, the adhesive hardly adheres to these surfaces. In addition, since the fixing plate is relatively thin, the adhesive strength between the side surface of the fixing plate and the adhesive as a mold is not high. For this reason, there has been a risk that the liquid adhering to the mold may enter the inside of the liquid ejection head through the adhesion interface between the mold and the inner peripheral surface of the exposure opening of the fixing plate or the outer peripheral surface of the fixing plate.

Means for Solving the Problems

[0005] According to a first aspect of the present disclosure, a liquid ejection head is provided. The liquid ejection head includes a head chip that ejects liquid in an ejection direction, a first surface facing the ejection direction, a second surface that is the surface to which the head chip is fixed and is opposite to the first surface, and a side surface that connects the first surface and the second surface. The liquid ejection head further includes a fixing plate having the above-described surfaces, and a holder that holds the head chip between the holder and the fixing plate. In a plan view seen from the direction facing the first surface, the first surface includes a water-repellent region having water repellency, and a hydrophilic region that is disposed between the water-repellent region and the side surface and has lower water repellency than the water-repellent region. A part of a mold disposed between the side surface and at least one of the head chip and the holder is adhered to the hydrophilic region of the first surface.

[0006] According to a second aspect of the present disclosure, a liquid ejection device is provided. The liquid ejection device includes the liquid ejection head according to the above aspect, and a liquid storage unit that stores liquid to be supplied to the liquid ejection head. BRIEF DESCRIPTION OF THE DRAWINGS

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Best Mode for Carrying Out the Invention

[0008] A. Embodiment: In the following description, an X-axis, a Y-axis, and a Z-axis that are mutually orthogonal are assumed. As illustrated in FIG. 2, one direction along the X-axis as viewed from an arbitrary point is denoted as the X1 direction, and the direction opposite to the X1 direction is denoted as the X2 direction. Similarly, the mutually opposite directions along the Y-axis from an arbitrary point are denoted as the Y1 direction and the Y2 direction, and the mutually opposite directions along the Z-axis from an arbitrary point are denoted as the Z1 direction and the Z2 direction. The X-Y plane including the X-axis and the Y-axis corresponds to the horizontal plane. The Z-axis is an axis along the vertical direction, and the Z2 direction corresponds to the downward direction in the vertical direction. Note that the X-axis, the Y-axis, and the Z-axis only need to intersect at an angle of approximately 90 degrees with each other. Also, in the accompanying drawings, the dimensions and scales of each part are appropriately different from the actual ones, and there are also parts schematically shown for easy understanding. Furthermore, if necessary, the X-axis, the Y-axis, and the Z-axis corresponding to FIG. 2 are also shown in other figures.

[0009] FIG. 1 is a configuration diagram of a liquid ejection device 100 in an embodiment. The liquid ejection device 100 is an inkjet printing device that ejects ink, which is an example of a liquid, as droplets onto a medium 11. The medium 11 is typically printing paper. However, for example, a printing target of any material such as a resin film or fabric is used as the medium 11. For example, examples of the ink include solvent ink and ultraviolet curable ink. Solvent ink is an ink containing an organic solvent, which forms a receiving layer by the organic solvent eroding the medium 11 after being applied to the medium 11 and fixes a coloring material on the receiving layer. Ultraviolet curable ink is an ink containing an ultraviolet curable component, which cures the ultraviolet curable component by irradiating ultraviolet light after being applied to the medium 11 and fixes a coloring material in the film formed thereby.

[0010] As illustrated in FIG. 1, a liquid container 12 as a liquid storage unit for storing ink is installed in the liquid ejection device 100. The liquid container 12 stores ink to be supplied to a liquid ejection head 252 described later. For example, a cartridge detachable from the liquid ejection device 100, an ink pack in a bag shape formed of a flexible film, or an ink tank capable of refilling ink is used as the liquid container 12. The liquid container 12 includes a first liquid container 12a and a second liquid container 12b. The first ink is stored in the first liquid container 12a, and the second ink is stored in the second liquid container 12b. The first ink and the second ink are different types of ink. As an example of the first ink and the second ink, the first ink may be cyan ink and the second ink may be magenta ink.

[0011] The liquid ejection device 100 is provided with a sub-tank 13 for temporarily storing ink. The ink supplied from the liquid container 12 is stored in the sub-tank 13. The sub-tank 13 includes a first sub-tank 13a for storing the first ink and a second sub-tank 13b for storing the second ink. The first sub-tank 13a is connected to the first liquid container 12a, and the second sub-tank 13b is connected to the second liquid container 12b. Further, the sub-tank 13 is connected to the head module 25, supplies ink to the head module 25, and recovers ink from the head module 25.

[0012] The liquid ejection device 100 includes a control unit 21, a transport mechanism 23, a movement mechanism 24, and a head module 25. The control unit 21 is a control unit that controls each element of the liquid ejection device 100. The control unit 21 includes one or more processing circuits such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and one or more storage circuits such as a semiconductor memory.

[0013] The conveying mechanism 23 conveys the medium 11 along the Y-axis under the control of the control unit 21. The moving mechanism 24 reciprocates the head module 25 along the X-axis under the control of the control unit 21. The moving mechanism 24 of the present embodiment includes a substantially box-shaped carrier 241 that houses the head module 25 and an endless belt 242 to which the carrier 241 is fixed. Note that a configuration in which the liquid container 12 and the sub-tank 13 are mounted on the carrier 241 together with the head module 25 may also be adopted.

[0014] The head module 25 discharges the ink supplied from the sub-tank 13 onto the medium 11 from each of a plurality of nozzles N under the control of the control unit 21. By the head module 25 injecting ink onto the medium 11 in parallel with the conveyance of the medium 11 by the conveying mechanism 23 and the repeated reciprocation of the carrier 241, an image is formed on the surface of the medium 11. Note that the ink that has not been ejected from the plurality of nozzles is discharged to the sub-tank 13.

[0015] In the present embodiment, the sub-tank 13 constitutes a part of an external flow path portion (not shown) installed outside the head module 25. The external flow path portion includes a flow path connecting the head module 25 and the sub-tank 13, and a circulation pump or the like for sending ink from the head module 25 to the sub-tank 13.

[0016] FIG. 2 is a perspective view of the head module 25. The head module 25 includes a support 251 and a plurality of liquid ejection heads 252. The support 251 is a plate-like member that supports the plurality of liquid ejection heads 252. A plurality of mounting holes 253 are formed in the support 251. Each liquid ejection head 252 is supported by the support 251 in a state of being inserted into the mounting hole 253. The plurality of liquid ejection heads 252 are arranged in a matrix along the X-axis and the Y-axis. However, the number of liquid ejection heads 252 and the arrangement pattern of the plurality of liquid ejection heads 252 are not limited to the above examples.

[0017] FIG. 3 is an exploded perspective view of the liquid ejection head 252. The liquid ejection head 252 includes a flow path structure 300, a wiring board 32, a plurality of head chips Hn, a fixing plate 36, and a cover 38. The flow path structure 300 includes a flow path member 31 and a holder 33.

[0018] The flow path member 31 is a member in which a liquid flow path through which ink flows is formed. The flow path member 31 includes a base 311, a first supply protrusion 312a, a second supply protrusion 312b, a first discharge protrusion 313a, and a second discharge protrusion 313b.

[0019] The base 311 is formed by laminating a substrate Su1, a substrate Su2, a substrate Su3, a substrate Su4, and a substrate Su5. The substrate Su1 is located at the uppermost layer in the vertical direction, and the substrate Su5 is located at the lowermost layer in the vertical direction. The plurality of substrates Su1, Su2, Su3, Su4, and Su5 are formed by, for example, injection molding of a resin material. Hereinafter, when the substrates Su1, Su2, Su3, Su4, and Su5 are not distinguished, they are referred to as substrate Su. The substrates Su1, Su2, Su3, Su4, and Su5 adjacent to each other are adhered by an adhesive. This adhesive may use the same material as the first adhesive described later.

[0020] Inside the substrate 311, as liquid flow paths, a first supply flow path Sa, a second supply flow path Sb, a first discharge flow path Da, and a second discharge flow path Db are provided. The first supply flow path Sa is a flow path for supplying the first ink stored in the first sub-tank 13a shown in FIG. 1 to a plurality of head chips Hn. The second supply flow path Sb is a flow path for supplying the second ink stored in the second sub-tank 13b shown in FIG. 1 to a plurality of head chips Hn. The first discharge flow path Da is a flow path for discharging the first ink not ejected from the plurality of head chips Hn to the first sub-tank 13a. The second discharge flow path Db is a flow path for discharging the second ink not ejected from the plurality of head chips Hn to the second sub-tank 13b. The first supply flow path Sa, the second supply flow path Sb, the first discharge flow path Da, and the second discharge flow path Db are each a space formed within the substrate 311. This space is formed by one or both of the grooves along the X-Y plane provided in each of the two mutually adjacent substrates Su.

[0021] As illustrated in FIG. 3, the first supply protrusion 312a, the second supply protrusion 312b, the first discharge protrusion 313a, and the second discharge protrusion 313b each protrude from the substrate 311 in the Z1 direction. The first supply protrusion 312a is a supply pipe provided with a first supply port Sa_in for supplying the first ink from the first sub-tank 13a to the first supply flow path Sa. The second supply protrusion 312b is a supply pipe provided with a second supply port Sb_in for supplying the second ink from the second sub-tank 13b to the second supply flow path Sb. The first discharge protrusion 313a is a discharge pipe provided with a first discharge port Da_out for discharging the first ink from the first discharge flow path Da to the first sub-tank 13a. The second discharge protrusion 313b is a discharge pipe provided with a second discharge port Db_out for discharging the second ink from the second sub-tank 13b to the second discharge flow path Db.

[0022] The holder 33 is a member that houses a plurality of head chips H1, H2, H3, and H4 and holds them between the fixing plate 36. In the following, when the head chips H1, H2, H3, and H4 are not distinguished, they are denoted as head chip Hn. The holder 33 is made of a metal material such as stainless steel, for example. Also, the holder 33 may be made of materials such as carbon steel, aluminum, or thermosetting resin. Further, the surface of the holder 33 may be plated with nickel or the like. The holder 33 is provided with a plurality of recesses 331, a plurality of ink holes 332, and a plurality of wiring holes 333. Each recess 331 houses a head chip Hn. Each ink hole 332 is a flow path for allowing ink to flow between the flow path member 31 and the head chip Hn. Each wiring hole 333 is a hole through which wiring (not shown) connecting the head chip Hn and the wiring board 32 passes. Also, the holder 33 has a flange 334 for fixing the holder 33 to the support 251 illustrated in FIG. 2. The flange 334 is a fixing portion provided with a plurality of screw holes 335 for screwing to the support 251.

[0023] Each head chip Hn ejects the ink supplied from the flow path member 31 in the ejection direction. The ejection direction is downward in the vertical direction, which is the Z2 direction. Although not shown in FIG. 3, it has a nozzle plate 41 having a plurality of nozzles N for ejecting ink. In each head chip Hn, the plurality of nozzles N include a plurality of nozzles N for ejecting the first ink and a plurality of nozzles N for ejecting the second ink.

[0024] The wiring board 32 is a mounting component for electrically connecting the liquid ejection head 252 to the control unit 21 illustrated in FIG. 1. The wiring board 32 is disposed on the flow path member 31. A connector 35 is installed on the wiring board 32. The connector 35 is a connecting component for electrically connecting the liquid ejection head 252 and the control unit 21. Also, although not shown, wiring connected to a plurality of head chips Hn is connected to the wiring board 32. Note that this wiring may be integrally formed with the wiring board 32.

[0025] As shown in FIG. 3, the fixing plate 36 is a plate member for fixing a plurality of head chips Hn to the holder 33 of the flow path structure 300. The fixing plate 36 is arranged in a state of sandwiching a plurality of head chips Hn between it and the holder 33. The fixing plate 36 is, for example, a plate material made of a metal material such as stainless steel. The fixing plate 36 has a first surface 36fa facing the injection direction, a second surface 36fb on the side opposite to the first surface 36fa, and a side surface 36s connecting the first surface 36fa and the second surface 36fb. Further, the fixing plate 36 has a plurality of exposure openings 361 for exposing the nozzle plate 41 of the head chip Hn to the outside. The exposure openings 361 penetrate the fixing plate 36 in a direction along the injection direction. The plurality of exposure openings 361 are provided individually for each head chip Hn. The side surface 36s of the fixing plate 36 has an outer peripheral surface 36s1 defining the outer periphery of the fixing plate 36 and an inner peripheral surface 36s2 defining the exposure openings 361.

[0026] The cover 38 is a box-shaped member for housing the base 311 of the flow path member 31 and the wiring board 32. The cover 38 is made of, for example, a resin material. Four projecting portion holes 381 and an opening 382 are provided in the cover 38. The first supply projecting portion 312a, the second supply projecting portion 312b, the first discharge projecting portion 313a or the second discharge projecting portion 313b is inserted into each projecting portion hole 381. The connector 35 is inserted into the opening 382. Note that the cover 38 may be provided with through holes on its side surface. When ink is injected, there is a risk that a gas containing an ink component may enter the cover 38. By providing the through holes, even when a gas containing an ink component enters the cover 38, the gas containing the ink component can be discharged to the outside through the through holes. Further, a tubular member and a pump may be connected to the through holes. In that case, by driving the pump, it becomes possible to forcibly discharge the gas containing the ink component in the cover 38 to the outside through the tubular member.

[0027] FIG. 4 is a cross-sectional view illustrating the configurations of the holder 33, the head chip Hn, and the fixing plate 36. The head chip Hn includes a nozzle plate 41, a communication plate 42, a pressure chamber substrate 43, a diaphragm 44, a plurality of drive elements E, a protection portion 46, a housing portion 47, and a compliance substrate 45.

[0028] The head chip Hn includes a first liquid ejection portion Qa and a second liquid ejection portion Qb. The first liquid ejection portion Qa ejects the first ink supplied from the first sub-tank 13a from a corresponding plurality of nozzles N. The second liquid ejection portion Qb ejects the second ink supplied from the second sub-tank 13b from other corresponding plurality of nozzles N. The first liquid ejection portion Qa has a first liquid storage chamber Ra which is a common liquid chamber continuous across a plurality of nozzles N corresponding to the first ink. The second liquid ejection portion Qb has a second liquid storage chamber Rb which is a common liquid chamber continuous across a plurality of nozzles N corresponding to the second ink. Also, the first liquid ejection portion Qa and the second liquid ejection portion Qb each include a plurality of pressure chambers C and a plurality of drive elements E. The pressure chamber C and the drive element E are formed for each nozzle N. Further, the head chip Hn is provided with supply holes Ra_in, Rb_in for supplying ink (not shown) and discharge holes Ra_out, Rb_out for discharging ink. The supply hole Ra_in and the discharge hole Ra_out communicate with the first liquid storage chamber Ra. Also, the supply hole Rb_in and the discharge hole Rb_out communicate with the second liquid storage chamber Rb.

[0029] The nozzle plate 41, the communication plate 42, the pressure chamber substrate 43, the diaphragm 44, the housing portion 47, and the compliance substrate 45 are each long plate-shaped members along the Y axis. The pressure chamber substrate 43 and the housing portion 47 are installed in the Z1 direction in the communication plate 42. On the other hand, the nozzle plate 41 and the compliance substrate 45 are installed in the Z2 direction in the communication plate 42. Note that the elements included in the first liquid ejection portion Qa and the elements included in the second liquid ejection portion Qb are arranged in a substantially plane-symmetrical structure. Therefore, in the following description, the elements corresponding to the first liquid ejection portion Qa will be mainly described, and the description of the elements corresponding to the second liquid ejection portion Qb will be omitted as appropriate.

[0030] The nozzle plate 41 is a plate-like member having a plurality of nozzles N. Each nozzle N is a through-hole for ejecting ink. The nozzle plate 41 is manufactured by processing a single-crystal silicon substrate using semiconductor manufacturing techniques such as photolithography and etching. However, known materials and manufacturing methods can be arbitrarily adopted for the manufacture of the nozzle plate 41. Ink is supplied to the nozzle N from the liquid flow path of the flow path member 31 via the first liquid storage chamber Ra and the like. In the present embodiment, a water-repellent film is formed on at least the surface of the nozzle plate 41 facing the ejection direction, so that the surface of the nozzle plate 41 has water repellency.

[0031] The communication plate 42 is provided with a communication flow path R1 and a supply flow path R2. The communication flow path R1 is provided for each nozzle N and communicates with the nozzle N. The supply flow path R2 communicates with the nozzle N and the first liquid storage chamber Ra, and supplies ink from the first liquid storage chamber Ra to the nozzle N. Further, a plurality of pressure chambers C are provided in the pressure chamber substrate 43. The pressure chamber C is a space that communicates with the nozzle N via the communication flow path R1. The pressure chamber C also communicates with the first liquid storage chamber Ra via the supply flow path R2. The communication plate 42 and the pressure chamber substrate 43 are manufactured by processing a single-crystal silicon substrate using semiconductor manufacturing techniques, for example. However, known materials and manufacturing methods can be arbitrarily adopted for the manufacture of the communication plate 42 and the pressure chamber substrate 43.

[0032] On the upper part of the pressure chamber C, a diaphragm 44 that can be elastically deformed is arranged. The diaphragm 44 is laminated on the pressure chamber substrate 43, and the communication plate 42 on the pressure chamber substrate 43 contacts the opposite surface. Note that part or all of the diaphragm 44 may be a separate member from the pressure chamber substrate 43 or may be integrated. On the surface of the diaphragm 44 on the side opposite to the pressure chamber C, a driving element E is formed for each pressure chamber C. The driving element E varies the pressure of the ink in the pressure chamber C. The driving element E is, for example, a piezoelectric element that changes the volume of the pressure chamber C by deforming the wall surface of the pressure chamber C. Note that the driving element E may be a heating element that generates bubbles in the pressure chamber C by heating the ink in the pressure chamber C. When the driving element E varies the pressure of the ink in the pressure chamber C, the ink in the pressure chamber C is ejected from the nozzle N.

[0033] A protection part 46 is arranged on the diaphragm 44. The protection part 46 protects a plurality of driving elements E and reinforces the mechanical strength of the pressure chamber substrate 43 and the diaphragm 44. The protection part 46 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing technology. Also, a wiring substrate (not shown) is joined to the surface of the diaphragm 44. The wiring substrate has a plurality of wirings formed therein for electrically connecting the control unit 21 and the liquid ejection head 252.

[0034] The housing part 47 is a case for storing the ink supplied to the plurality of pressure chambers C, and is formed, for example, by injection molding of a resin material. A first liquid storage chamber Ra and a second liquid storage chamber Rb are formed in the housing part 47. The first liquid storage chamber Ra and the second liquid storage chamber Rb communicate with the liquid flow path of the flow path member 31 through the ink holes 332 of the holder 33, respectively.

[0035] ​The compliance substrate 45 forms part of the wall surface of the supply channel R2. The compliance substrate 45 has a sealing film 451 and a support plate 452. The sealing film 451 is a flexible film and contacts the communication plate 42. The sealing film 451 is formed of a resin material such as polyphenylene sulfide or aromatic polyamide, for example. The support plate 452 is provided on the surface of the sealing film 451 opposite to the communication plate 42. The support plate 452 is formed of a metal such as stainless steel, for example. The support plate 452 has an opening penetrating in its thickness direction. Therefore, the portion of the compliance substrate 45 where the support plate 452 is not provided is composed of only the sealing film 451. This portion has a buffering function of absorbing the pressure fluctuations of the ink in the first liquid storage chamber Ra and the second liquid storage chamber Rb. That is, this portion functions as a buffer portion.

[0036] The holder 33 and the fixing plate 36 are adhered by a first adhesive 62a. Also, the compliance substrate 45 of the head chip Hn and the fixing plate 36 are adhered by a second adhesive 62b. Since the first adhesive 62a and the second adhesive 62b are the same material, when used without distinction, the adhesive 62 is used. The adhesive 62 is composed of an organic adhesive. In the present embodiment, the adhesive 62 is a silicone-based adhesive that cures at room temperature. The silicone-based adhesive has the advantages of being easy to handle and having excellent heat resistance. Further, the silicone-based adhesive is preferably moisture-curing type. By being moisture-curing type, the handling of the adhesive 62 is particularly easy, and thus, the adhesion efficiency between the nozzle plate 41 and the holder 33 and the adhesion between the nozzle plate 41 and the compliance substrate 45 can be improved. However, an epoxy-based adhesive may be used as the adhesive 62. For example, as the adhesive 62, an adhesive containing bisphenol A type epoxy resin may be used. Also, as the adhesive 62, an adhesive mainly composed of calcium carbonate or polyoxyalkylene glycol glycidyl ether may be used.

[0037] Also, a mold 51 is disposed between the holder 33 and the fixed plate 36, and between the nozzle plate 41 and the fixed plate 36, respectively. The mold 51 is formed of a thermosetting resin or a photocurable resin. The mold 51 is preferably formed of, for example, an epoxy resin. By using an epoxy-based adhesive, it is easy to form the mold 51 having excellent filling properties. The mold 51 includes a first mold 51a disposed between the outer peripheral surface 36s1 of the fixed plate 36 and the holder 33, and a second mold 51b disposed between the inner peripheral surface 36s2 and the nozzle plate 41 of the head chip Hn. Specifically, at least a part of the first mold 51a is located between the outer peripheral surface 36s1 and the holder 33 in a direction perpendicular to the Z direction along the injection direction, for example, the X direction or the Y direction. Also, at least a part of the second mold 51b is disposed between the inner peripheral surface 36s2 and the nozzle plate 41 in a direction perpendicular to the Z direction along the injection direction.

[0038] The chemical resistance A1 of the mold 51 including the first mold 51a and the second mold 51b is higher than the chemical resistance B1 of the adhesive 62. The reactivity between the liquid ink, the adhesive 62, and the mold 51 can be numerically compared by comparing the solubility parameters of the ink and the adhesive 62 and the solubility parameters of the ink and the mold 51. Specifically, the fact that the chemical resistance A1 is higher than the chemical resistance B1 means that when the solubility parameter of the adhesive 62 is SPa, the solubility parameter of the mold 51 is SPb, and the solubility parameter of the ink is SPz, SPa and SPb satisfy the relationship |SPb - SPz| > |SPa - SPz|. Satisfying the relationship |SPb - SPz| > |SPa - SPz| means that the reactivity between the ink and the mold 51 is smaller than the reactivity between the ink and the adhesive 62, that is, the chemical resistance is high.

[0039] In the liquid ejection head 252, generally, when the adhesive strength between two members is not high, that is, when the adhesion between the two members is low, a gap is likely to occur at the adhesive interface, and ink as a liquid is likely to penetrate from the outside to the inside through this gap. For example, when the adhesion between the mold 51 and the nozzle plate 41 is low, ink may penetrate into the inside from the adhesive interface between the mold 51 and the nozzle plate 41. When the ink penetrates into the inside, the ink may reach the first adhesive 62a or the second adhesive 62b. In the present embodiment, the first adhesive 62a and the second adhesive 62b are room temperature curable silicone-based adhesives with low liquid resistance. Therefore, the layer of the first adhesive 62a or the second adhesive 62b is likely to be damaged by the reached ink.

[0040] Also, in the process of forming a water-repellent film on the surface including the first surface 36fa and the second surface 36fb of the fixing plate 36, the water-repellent film may be formed on the outer peripheral surface 36s1 and the inner peripheral surface 36s2. In such a case, since the adhesive strength between the first mold 51a and the outer peripheral surface 36s1 and the adhesive strength between the second mold 51b and the inner peripheral surface 36s2 decrease, the adhesive strength between the mold 51 and the nozzle plate 41 further decreases, so the above-described problem of ink penetrating from the outside to the inside is likely to occur significantly.

[0041] Furthermore, when mechanical stress is applied to the fixing plate 36, the mold 51 may peel off from the side surface 36s at the adhesive interface between the side surface 36s of the fixing plate 36 and the mold 51. When the mold 51 peels off from the side surface 36s, ink may penetrate into the inside of the liquid ejection head 252 from the peeled portion. Furthermore, since it is difficult to stably adhere the mold 51 to the entire side surface 36s of the fixing plate 36, there is also a possibility that the mold 51 is adhered only to a part of the side surface 36s. When the mold 51 is adhered only to a part of the side surface 36s, the adhesive strength between the mold 51 and the fixing plate 36 is likely to decrease.

[0042] FIG. 5 is a plan view of the liquid ejection head 252 as viewed toward the first surface 36fa. FIG. 6 is a sectional view taken along line VI-VI of FIG. 5. In FIG. 6, for ease of understanding, illustration of the configuration disposed in the recess 331 is omitted.

[0043] As shown in FIG. 5, in plan view, the first surface 36fa of the fixed plate 36 has a water-repellent region Rt having water repellency and a hydrophilic region Rh having lower water repellency than the water-repellent region Rt. The water-repellent region Rt is a region where a water-repellent film is formed on the first surface 36fa of the fixed plate 36. The water-repellent film contains, for example, a functional group having fluorine. Note that the side surface 36s also has water repellency by forming a water-repellent film in the same manner as the water-repellent region Rt. In plan view, the hydrophilic region Rh is disposed between the water-repellent region Rt and the side surface 36s. For ease of understanding, in the first surface 36fa, the hydrophilic region Rh is hatched singly, and the water-repellent region Rt is not hatched.

[0044] The hydrophilic region Rh includes a first region Rh1 disposed along the outer peripheral surface 36s1 of the fixed plate 36 and a second region Rh2 disposed along the inner peripheral surface 36s2 of the fixed plate 36. The first region Rh1 is disposed along the entire outer edge of the first surface 36fa. The second region Rh2 is disposed along the entire periphery of the edge of the exposure opening 361.

[0045] The hydrophilic region Rh is formed, for example, by removing the water-repellent film by irradiating a laser to the region to be the hydrophilic region Rh among the water-repellent films formed on the entire surface of the first surface 36fa by dip coating. Note that the second surface 36fb of the fixed plate 36 shown in FIG. 3 is configured by a hydrophilic region having lower water repellency than the water-repellent region Rt. The hydrophilic region of the second surface 36fb is formed, for example, by removing the water-repellent film by irradiating a laser to the water-repellent film formed on the entire surface of the second surface 36fb by dip coating in the same manner as the hydrophilic region Rh of the first surface 36fa.

[0046] In the present embodiment, "having water repellency" means that the static contact angle with respect to pure water is 90 degrees or more. Further, in the hydrophilic region Rh, the static contact angle with respect to pure water is preferably less than 90 degrees, more preferably less than 45 degrees, and even more preferably less than 30 degrees.

[0047] As shown in FIG. 6, the holder 33 has an outer peripheral wall 338 that defines a recess 331 for accommodating the head chip Hn. The outer peripheral wall 338 is a side wall that extends from the bottom of the recess 331 in the ejection direction. The outer peripheral wall 338 has a bottom surface 339 that forms an end portion on the ejection direction side. The bottom surface 339 faces the Z2 direction, which is the ejection direction. The bottom surface 339 has a groove 337 that is recessed in the direction opposite to the ejection direction. Of the bottom surface 339, the inner bottom surface 339a located on the inner side of the groove 337, that is, between the groove 337 and the recess 331, is a plane facing the Z2 direction. The inner bottom surface 339a of the bottom surface 339 is fixed to the second surface 36fb by an adhesive 62. That is, the outer peripheral wall 338 is fixed to the second surface 36fb by the adhesive 62 at the inner bottom surface 339a. The groove 337 is formed at a position overlapping the outer peripheral surface 36s1 of the fixing plate 36 in a plan view seen from the first surface 36fa. That is, in the direction along the plane of the fixing plate 36, the outer peripheral surface 36s1 of the fixing plate 36 protrudes outward from the inner bottom surface 339a. The adhesive 62 in the present embodiment is located in an adhesive region sandwiched between the inner bottom surface 339a and the second surface 36fb, and a region protruding outside the adhesive region. Further, in the present embodiment, the adhesive 62 is not adhered to the edge 36t where the second surface 36fb and the side surface 36s intersect and a region up to a certain distance from the edge 36t on the second surface 36fb.

[0048] In the first region Rh1 of the first surface 36fa, a part of the first mold 51a disposed between the outer peripheral surface 36s1 of the side surface 36s and the holder 33 is adhered. Specifically, the first mold 51a is filled in the groove 337 so as to cover the first region Rh1. Thereby, the first mold 51a covers the first adhesive 62a protruding into the groove 337. As described above, a part of the first mold 51a is disposed inside the groove 337. By disposing a part of the first mold 51a inside the groove 337, the contact area between the holder 33 and the first mold 51a can be increased, so that the adhesion strength between the holder 33 and the first mold 51a can be improved.

[0049] The water-repellent region Rt is a region where the water-repellent film Ly is formed as described above. Although not shown, the side surface 36s also has water repellency by forming a water-repellent film on the side surface 36s. In the present embodiment, the first region Rh1 of the first surface 36fa is formed between the water-repellent region Rt and the outer peripheral surface 36s1 so as to be adjacent to the outer peripheral surface 36s1 which is the side surface 36s. That is, the first region Rh1 extends from the first edge portion 36p1 where the outer peripheral surface 36s1 and the first surface 36fa intersect to the end of the water-repellent region Rt. Similarly, as shown in FIG. 5, the second region Rh2 of the first surface 36fa is formed between the water-repellent region Rt and the inner peripheral surface 36s2 so as to be adjacent to the inner peripheral surface 36s2 which is the side surface 36s. That is, the second region Rh2 extends from the second edge portion 36p2 where the inner peripheral surface 36s2 and the first surface 36fa intersect to the outer peripheral portion of the water-repellent region Rt.

[0050] Further, as shown in FIG. 6, a part of the first mold 51a is adhered to the second surface 36fb. Specifically, a part of the first mold 51a is adhered to a region adjacent to the edge portion 36t of the second surface 36fb. When viewed in the injection direction, a part of the first mold 51a on the hydrophilic region Rh and a part of the first mold 51a on the second surface 36fb overlap. That is, the first mold 51a exists on both sides of the fixing plate 36. Since the first mold 51a exists across both the first surface 36fa and the second surface 36fb, the adhesion strength between the fixing plate 36 and the first mold 51a can be further improved.

[0051] In a plan view of the liquid ejection head 252 looking toward the first surface 36fa, the dimension Lh1 of the first region Rh1 in the arrangement direction (corresponding to the X direction in FIG. 6) of the outer peripheral surface 36s1 and the first region Rh1 adjacent to each other is larger than the thickness Lt of the fixing plate 36. Note that the thickness Lt of the fixing plate 36 is the maximum thickness and, in the present embodiment, is the thickness of the portion where the water-repellent film Ly is formed. Thereby, the area of the first region Rh1 to which the first mold 51a adheres can be increased, so that the adhesion strength of the first mold 51a to the first region Rh1 can be improved. As a result, ink adhering to the first mold 51a or the like can be more effectively prevented from entering the inside of the liquid ejection head 252 from the outside through the adhesion interface between the first mold 51a and the outer peripheral surface 36s1. Note that it is more preferable that the dimension Lh1 is larger than twice the thickness Lt. By doing so, the area of the first region Rh1 to which the first mold 51a adheres can be further increased, so that the adhesion strength of the first mold 51a to the first region Rh1 can be further improved. Therefore, ink can be further effectively prevented from entering the inside of the liquid ejection head 252 from the outside.

[0052] Also, in a plan view of the liquid ejection head 252 as seen toward the first surface 36fa, in the arrangement direction (corresponding to the X direction in FIG. 6) of the outer peripheral surface 36s1, which is a side surface 36s adjacent to each other, and the first region Rh1, the dimension Lh1 of the first region Rh1 has a relationship of being smaller than the dimension Lp of the portion disposed between the outer peripheral surface 36s1 and the holder 33 in the first mold 51a. Here, when the portion adhered on the fixing plate 36 in the first mold 51a is wide, due to the stress caused by the shrinkage during the curing of the first mold 51a, a part of the first mold 51a may be peeled off from the first region Rh1. On the other hand, by having the above relationship, the portion of the first mold 51a adhered to the first region Rh1 can be made less susceptible to the stress caused by the shrinkage during curing, so the possibility of a part of the first mold 51a being peeled off from the first region Rh1 can be reduced. Also, by having the above relationship, the area of the first mold 51a adhered to the first surface 36fa can be made smaller, so a sufficient seal region where the capping member covering the nozzle N abuts against the first surface 36fa can be ensured to prevent the ink in the nozzle N from drying.

[0053] Also, it is preferable that the first region Rh1 is formed in a region Rp1 between the first edge portion 36p1 of the fixing plate 36 and a position inward by the dimension Lp from the first edge portion 36p1. Thereby, the amount of the first mold 51a can be further reduced, so the possibility of a part of the first mold 51a being peeled off from the first region Rh1 can be further reduced. Also, thereby, a more sufficient seal region where the capping member for covering the nozzle N abuts against the first surface 36fa can be ensured.

[0054] As described above, the fixing plate 36 and the holder 33 are fixed by a first adhesive 62 disposed between the second surface 36fb of the fixing plate 36 and the inner bottom surface 339a of the holder 33. Also, a part of the first mold 51a is adhered to the second surface 36fb. Specifically, a part of the first mold 51a is adhered from the edge 36t to the portion where the first adhesive 62a is located on the second surface 36fb. In the present embodiment, since the first mold 51a is disposed from the first surface 36fa to the second surface 36fb of the fixing plate 36, the adhesive strength between the fixing plate 36 and the first mold 51a can be further improved. Further, since the liquid resistance A1 of the first mold 51a is higher than the liquid resistance A2 of the adhesive 62, the intrusion of liquid from the outside into the liquid injection head 252 can be suppressed, so that the adhesive 62 with low liquid resistance can be protected.

[0055] FIG. 7 is a schematic cross-sectional view of a region including the second mold 51b. The second mold 51b is disposed between the inner peripheral surface 36s2 as the side surface 36s and the head chip Hn. Specifically, the second mold 51b is disposed so as to fill the gap between the inner peripheral surface 36s2 and the nozzle plate 41. A part of the second mold 51b is located on the second region Rh2 and adhered to the second region Rh2. Since the second region Rh2 has lower water repellency than the water repellent region Rt, the adhesive strength between the second region Rh2 and the second mold 51b can be improved. Thereby, it is possible to suppress the external ink adhering to the second mold 51b or the like from entering the inside of the liquid injection head 252 through the adhesion interface between the second mold 51b and the inner peripheral surface 36s2.

[0056] Further, in a plan view of the liquid ejection head 252 as viewed toward the first surface 36fa, in the arrangement direction (corresponding to the X direction in FIG. 7) of the inner peripheral surface 36s2 and the second region Rh2, which are adjacent side surfaces 36s, the dimension Lh2 of the second region Rh2 is larger than the thickness Lt of the fixing plate 36 shown in FIG. 6. Thereby, since the area of the second region Rh2 to which the second mold 51b adheres can be increased, the adhesion strength of the second mold 51b to the second region Rh2 can be improved. As a result, ink adhering to the second mold 51b or the like can be more effectively suppressed from entering the inside of the liquid ejection head 252 from the outside through the adhesion interface between the second mold 51b and the inner peripheral surface 36s2. Note that it is more preferable that the dimension Lh2 is larger than twice the thickness Lt. By doing so, the area of the second region Rh2 to which the second mold 51b adheres can be further increased, so that the adhesion strength of the second mold 51b to the second region Rh2 can be further improved. Therefore, ink can be further suppressed from entering the inside of the liquid ejection head 252 from the outside.

[0057] Further, in a plan view of the liquid ejection head 252 as viewed toward the first surface 36fa, in the arrangement direction (corresponding to the X direction in FIG. 7) of the inner peripheral surface 36s2 and the second region Rh2, which are adjacent side surfaces 36s, the dimension Lh2 of the second region Rh2 has a relationship of being smaller than the dimension Lr of the portion of the second mold 51b disposed between the inner peripheral surface 36s2 and the nozzle plate 41. Here, when the portion where the second mold 51b is adhered on the fixing plate 36 is wide, a part of the second mold 51b may be peeled off from the second region Rh2 due to the stress caused by the shrinkage during curing of the second mold 51b. On the other hand, by having the above relationship, the portion of the second mold 51b adhered to the second region Rh2 can be made less susceptible to the stress caused by the shrinkage during curing, so that the possibility of a part of the second mold 51b being peeled off from the second region Rh2 can be reduced.

[0058] Further, it is preferable that the second region Rh2 is formed in a region Rp2 between the second edge portion 36p2 of the fixing plate 36 and a position separated from the inner peripheral surface 36s2 by a dimension Lr from the second edge portion 36p2. Thereby, the amount of the second mold 51b can be reduced, and the possibility that a part of the mold 51 peels off from the second region Rh2 can be further reduced.

[0059] According to the above embodiment, as shown in FIGS. 6 and 7, a part of the mold 51 is adhered to the hydrophilic region Rh of the first surface 36fa. Specifically, as shown in FIG. 6, a part of the first mold 51a is adhered to the first region Rh1. Further, as shown in FIG. 7, a part of the second mold 51b is adhered to the second region Rh2. Since the hydrophilic region Rh has a high affinity with the mold 51, the adhesion strength between the hydrophilic region Rh and the mold 51 can be improved. Therefore, the adhesion strength between the fixing plate 36 and the mold 51 can be improved. Thereby, the possibility that ink enters inside from between the first surface 36fa and the mold 51 can be reduced, and the entry of external ink into the adhesion interface between the side surface 36s and the mold 51 can be suppressed. Therefore, the arrival of ink at the adhesive 62 can be suppressed, and the possibility of the adhesive 62 being damaged can be reduced. Further, since a part of the mold 51 is adhered to the hydrophilic region Rh of the first surface 36fa that is visible from the outside of the liquid ejection head 252, bubbles enter the invisible mold 51 and the mold 51 and the second surface 36fb or the side surface 36s are not sufficiently adhered. It is possible to suppress the occurrence of poor adhesion of the mold 51.

[0060] Also, according to the above embodiment, as shown in FIGS. 6 and 7, the hydrophilic region Rh of the first surface 36fa is disposed between the water-repellent region Rt and the side surface 36s so as to be adjacent to the side surface 36s. Here, when the water-repellent region Rt, the hydrophilic region Rh, and the water-repellent region Rt are arranged in order from the edges 36p1 and 36p2 adjacent to the side surface 36s of the first surface 36fa, since the distance from the side surface 36s to the hydrophilic region Rh is long, the amount of the mold 51 used increases, and the height of the mold increases. On the other hand, according to this embodiment, since the hydrophilic region Rh of the first surface 36fa is adjacent to the side surface 36s, the distance from the side surface 36s to the hydrophilic region Rh can be shortened while forming a hydrophilic region Rh having a certain area or more. For this reason, the amount of the mold 51 used can be reduced, and the height of the mold 51 can be suppressed. Further, since the amount of the mold 51 used can be reduced, the stress along the first surface 36fa generated by the curing shrinkage of the portion disposed between the side surface 36s and at least one of the head chip Hn and the holder 33 in the mold 51 can be reduced. Thereby, the possibility that the mold 51 peels off from the first surface 36fa can be further reduced.

[0061] Also, according to the above embodiment, the side surface 36s of the fixing plate 36 has water repellency. Here, when the fixing plate 36 is subjected to a water-repellent treatment by dip coating, a water-repellent film Ly is also formed on the side surface 36s. Although the water-repellent film on the side surface 36s having a small dimension in the Z direction tends to be difficult to remove, even when the side surface 36s has water repellency, a part of the mold 51 is adhered to the hydrophilic region Rh of the first surface 36fa, so that ink from the outside can be prevented from entering the adhesion interface between the side surface 36s and the mold 51. That is, it is possible to suppress ink from the outside from entering the adhesion interface between the side surface 36s and the mold 51 without removing the water-repellent film on the side surface 36s.

[0062] B. Other Embodiments: B-1. Other Embodiment 1: In the above-described embodiment, as shown in FIG. 6, the first mold 51a was adhered not only to the first surface 36fa but also to the second surface 36fb. However, other embodiments are not limited to this. FIG. 8 is a diagram for explaining another embodiment 1. The difference between the embodiment and the other embodiment shown in FIG. 8 is that the first adhesive 62a reaches the edge portion 36t. That is, the first adhesive 62a is disposed over the entire region of the second surface 36fb that faces the groove 337. As a result, a part of the first mold 51a is not located on the second surface 36fb and is not adhered to the second surface 36fb. Even in this case, since the liquid resistance A1 of the first mold 51a is higher than the liquid resistance B1 of the adhesive 62, it is possible to suppress the intrusion of liquid from the outside into the liquid injection head 252, and thus the adhesive 62 with low liquid resistance can be protected.

[0063] B-2. Another Embodiment 2: FIG. 9 is a diagram for explaining another embodiment 2. The difference from the embodiment is that the outer peripheral wall 338a does not have the groove 337 shown in FIG. 6. Regarding other configurations, since they are the same as those of the first implementation liquid, the same reference numerals are given to the same configurations as those of the embodiment, and the description is omitted as appropriate.

[0064] As shown in FIG. 9, the second surface 36fb of the fixing plate 36 is adhered to the bottom surface 339 of the outer peripheral wall 338a by the first adhesive 62a. A part of the first adhesive 62a protrudes outside the region between the second surface 36fb and the bottom surface 339. The first mold 51a is disposed between the outer peripheral surface 36s1 and the outer peripheral wall 338a of the holder 33 in a state of covering the first region Rh1 and the first mold 51a protruding on the bottom surface 339. A part of the first mold 51a is adhered to the first region Rh1. Even in this case, the same effects as those of the above-described embodiment are achieved in that it has the same configuration as the above-described embodiment. For example, since the first region Rh1 has lower water repellency than the water repellent region Rt, the adhesive strength between the first mold 51a and the first region Rh1 can be improved. Thereby, it is possible to suppress the ink attached to the first mold 51a from entering the adhesion interface between the first mold 51a and the outer peripheral surface 36s1, and thus it is possible to suppress the external ink from entering the inside of the liquid ejection head 252.

[0065] B-3. Other Embodiment 3: FIG. 10 is a diagram for explaining another Embodiment 3. The difference between another Embodiment 3 and the embodiment shown in FIG. 7 is that in another Embodiment 3, a part of the second mold 51b is adhered to the surface 41fa of the nozzle plate 41a. In the above embodiment, a water-repellent film is formed over the entire surface 41fa of the nozzle plate 41 facing the ejection direction to suppress ink adhesion. On the other hand, in another Embodiment 3, the surface 41fa of the nozzle plate 41a has a hydrophilic region Rh3 with low water repellency from which the water-repellent film Ly has been removed, similar to the first surface 36fa of the fixing plate 36. Specifically, in a plan view looking toward the first surface 36fa, the surface 41fa of the nozzle plate 41a has a nozzle forming region Rt3 having water repellency in which a plurality of nozzles N are formed, and a hydrophilic region Rh3 disposed between the outer peripheral surface 41s2 of the nozzle plate 41a and the nozzle forming region Rt3. The hydrophilic region Rh3 has lower water repellency than the nozzle forming region Rt3. In another Embodiment 3, the water-repellent film Ly is removed by laser, making the water repellency of the hydrophilic region Rh3 lower than that of the nozzle forming region Rt3. Note that the outer peripheral surface 41s2 of the nozzle plate 41a is a side surface that defines the outer periphery of the nozzle plate 41a. A part of the second mold 51b is disposed in the hydrophilic region Rh3 of the nozzle plate 41a and is adhered to the hydrophilic region Rh3. By doing so, the adhesiveness between the second mold 51b and the nozzle plate 41a can be improved, suppressing ink from entering the interior of the liquid ejection head 252 between the second mold 51b and the nozzle plate 41a.

[0066] B-4. Another Embodiment 4: According to the above embodiment, as shown in FIGS. 6 and 7, the hydrophilic region Rh of the first surface 36fa was adjacent to the side surface 36s, but it is not limited thereto. For example, a water-repellent region may be provided in a region of the first surface 36fa adjacent to the side surface 36s, and a hydrophilic region Rh may be provided adjacent to this water-repellent region. That is, the hydrophilic region Rh may be disposed at a distance from the first edge 36p1 or the second edge 36p2 of the first surface 36fa. Also, a part of the hydrophilic region Rh of the first surface 36fa may be adjacent to the side surface 36s, and the remaining part of the hydrophilic region Rh may be disposed at a distance from the side surface 36s.

[0067] B-5. Other Embodiment 5: According to the above embodiment, as shown in FIGS. 6 and 7, the side surface 36S was a surface extending in the Z direction, but is not limited thereto. For example, the side surface 36S may be an inclined surface extending in a direction intersecting the Z direction when viewed in a direction perpendicular to the Z direction which is the thickness direction of the fixing plate 36, or may be a curved surface.

[0068] B-6. Other Embodiment 6: According to the above embodiment, the holder 33 was integrally formed, but may be formed by fixing a plurality of two or more members by adhesion or the like.

[0069] C. Other Forms: The present disclosure is not limited to the above-described embodiments, and can be realized in various forms without departing from the gist thereof. For example, the present disclosure can also be realized by the following forms. The technical features in the above embodiments corresponding to the technical features in each of the following forms can be appropriately replaced or combined in order to solve part or all of the problems of the present disclosure, or to achieve part or all of the effects of the present disclosure. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0070] (1) According to the first aspect of the present disclosure, a liquid ejection head is provided. This liquid ejection head includes a head chip that ejects liquid in the ejection direction, a first surface facing the ejection direction, a second surface that is the surface to which the head chip is fixed and is on the opposite side of the first surface, and a side surface that connects the first surface and the second surface. The liquid ejection head further includes a fixing plate having these components, and a holder that holds the head chip between the holder and the fixing plate. In a plan view seen toward the first surface, the first surface includes a water-repellent region having water repellency, and a hydrophilic region disposed between the water-repellent region and the side surface and having lower water repellency than the water-repellent region. A part of a mold disposed between the side surface and at least one of the head chip and the holder is adhered to the hydrophilic region of the first surface. According to this aspect, since a part of the mold is adhered to the hydrophilic region of the first surface, it is possible to suppress ink from the outside from entering the adhesion interface between the side surface and the mold.

[0071] (2) In the above aspect, the hydrophilic region of the first surface may be disposed between the water-repellent region and the side surface so as to be adjacent to the side surface. When the water-repellent region, the hydrophilic region, and the water-repellent region are arranged in order from the edge adjacent to the side surface of the first surface, the distance from the side surface to the hydrophilic region is long, so the amount of the mold used increases, and the height of the mold tends to increase. On the other hand, according to this aspect, since the hydrophilic region of the first surface is adjacent to the side surface, the distance from the side surface to the hydrophilic region can be shortened. Therefore, the amount of the mold used can be reduced, and the height of the mold can be suppressed. In addition, since the amount of the mold used can be reduced, it is possible to reduce the stress along the first surface generated by the curing shrinkage of the portion of the mold disposed between the side surface and at least one of the head chip and the holder. As a result, the possibility of the mold peeling off from the first surface can be further reduced.

[0072] (3) In the above aspect, the side surface may have water repellency. According to this aspect, even when the side surface has water repellency, by adhering a part of the mold to the hydrophilic region of the first surface, it is possible to suppress ink from the outside from entering the adhesion interface between the side surface and the mold.

[0073] (4) In the above-described embodiment, a part of the mold may be adhered to the second surface. According to this embodiment, since the mold exists across both the first surface and the second surface, the adhesion strength between the fixing plate and the mold can be further improved.

[0074] (5) In the above-described embodiment, the side surface includes the outer peripheral surface of the fixing plate, the mold includes a first mold disposed between the outer peripheral surface of the fixing plate and the holder, the hydrophilic region of the first surface includes a first region disposed along the outer peripheral surface of the fixing plate, and a part of the first mold may be adhered to the first region. According to this embodiment, by adhering a part of the first mold to the first region which is the hydrophilic region, the adhesion strength between the fixing plate and the mold can be improved.

[0075] (6) In the above-described embodiment, the dimension of the first region in the arrangement direction of the side surface and the first region adjacent to each other in plan view may be larger than the thickness of the fixing plate. According to this embodiment, since the area of the first region to which the first mold adheres can be increased, the adhesion strength of the first mold to the first region can be improved. Thereby, it is possible to further suppress ink from entering the inside of the liquid ejection head from the outside.

[0076] (7) In the above-described embodiment, in the arrangement direction of the side surface and the first region that are adjacent to each other in the plan view, the dimension of the first region may be smaller than the dimension of the portion of the first mold disposed between the side surface and the holder. Here, when the portion where the mold is adhered on the fixing plate is wide, due to the stress caused by the shrinkage during the curing of the mold, a part of the mold may be peeled off from the first region. On the other hand, by having the above relationship, the portion of the mold adhered to the first region can be made less susceptible to the stress caused by the shrinkage during curing, so the possibility of a part of the mold peeling off from the first region can be reduced. Also, by having the above relationship, the area of the first mold adhered to the first surface can be reduced, so a sufficient sealing region where the capping member covering the nozzle abuts against the first surface can be ensured to prevent the ink in the nozzle from drying.

[0077] (8) In the above-described embodiment, the second surface and the holder are fixed by an adhesive disposed between the second surface and the holder, a part of the first mold is adhered to the second surface, and the liquid resistance of the first mold may be higher than the liquid resistance of the adhesive. According to this embodiment, since the first mold is disposed from the first surface to the second surface of the fixing plate, the adhesive strength between the fixing plate and the first mold can be further improved. Furthermore, since the liquid resistance of the first mold is higher than the liquid resistance of the adhesive, the intrusion of liquid from the outside into the liquid injection head can be suppressed, so the adhesive with low liquid resistance can be protected.

[0078] (9) In the above-described embodiment, the second surface and the holder are fixed by an adhesive disposed between the second surface and the holder, a part of the first mold is not adhered to the second surface, and the liquid resistance of the first mold may be higher than the liquid resistance of the adhesive. According to this embodiment, since the liquid resistance of the first mold is higher than the liquid resistance of the adhesive, the intrusion of liquid from the outside into the liquid injection head can be suppressed, so the adhesive with low liquid resistance can be protected.

[0079] (10) In the above-described embodiment, the holder has an outer peripheral wall fixed to the second surface by an adhesive on the bottom surface facing the injection direction. A groove is formed in the bottom surface of the outer peripheral wall at a position overlapping the outer peripheral surface of the fixing plate in the plan view, and a part of the first mold may be disposed inside the groove. According to this embodiment, by disposing a part of the first mold inside the groove, the contact area between the holder and the first mold can be increased, so that the adhesion strength between the holder and the first mold can be improved.

[0080] (11) In the above-described embodiment, the head chip includes a nozzle plate having a plurality of nozzles for injecting liquid. The fixing plate has an exposure opening for exposing the nozzle plate to the outside. The side surface includes an inner peripheral surface defining the exposure opening of the fixing plate. The mold includes a second mold disposed between the inner peripheral surface and the nozzle plate. The hydrophilic region of the first surface includes a second region disposed along the inner peripheral surface, and a part of the second mold may be adhered to the second region. According to this embodiment, by adhering a part of the second mold to the second region, which is the hydrophilic region, the adhesion strength between the fixing plate and the mold can be improved.

[0081] (12) In the above-described embodiment, in the arrangement direction of the side surface and the second region adjacent to each other in the plan view, the dimension of the second region may be larger than the thickness of the fixing plate. According to this embodiment, the area of the second region to which the second mold adheres can be increased, so that the adhesion strength of the second mold to the second region can be improved. Thereby, it is possible to further suppress ink from entering the inside of the liquid injection head from the outside.

[0082] (13) In the above-described embodiment, in the arrangement direction of the side surface and the second region that are adjacent to each other in the plan view, the dimension of the second region may be smaller than the dimension of the portion of the second mold disposed between the side surface and the nozzle plate. Here, when the portion of the mold adhered on the fixing plate is wide, due to the stress caused by the shrinkage during the curing of the mold, a part of the mold may be peeled off from the first region. On the other hand, according to this embodiment, the portion of the mold adhered to the second region can be less affected by the stress caused by the shrinkage during curing, so the possibility of a part of the mold being peeled off from the second region can be reduced.

[0083] (14) According to the above-described embodiment, in the plan view, the surface of the nozzle plate has a water-repellent nozzle forming region where the plurality of nozzles are formed, and a hydrophilic region disposed between the outer peripheral surface of the nozzle plate and the nozzle forming region and having lower water repellency than the nozzle forming region, and a part of the second mold may be disposed in the hydrophilic region of the nozzle plate. According to this embodiment, the adhesiveness between the second mold and the nozzle plate can be improved.

[0084] (15) According to the second embodiment of the present disclosure, a liquid ejection device is provided. This liquid ejection device includes the liquid ejection head of the above-described embodiment and a liquid storage unit that stores the liquid supplied to the liquid ejection head. According to this embodiment, since a part of the mold is adhered to the hydrophilic region of the first surface, it is possible to suppress the intrusion of ink from the outside into the adhesion interface between the side surface and the mold.

[0085] The present disclosure can also be realized in various other forms than the above. For example, it can be realized in forms such as a manufacturing method of a liquid ejection head or a liquid ejection device.

Description of Reference Numerals

[0086] 11… Medium, 12… Liquid container, 12a… First liquid container, 12b… Second liquid container, 13… Sub-tank, 13a… First sub-tank, 13b… Second sub-tank, 21… Control unit, 23… Conveyor mechanism, 24… Moving mechanism, 25… Head module, 26… Liquid injection head, 31… Flow path member, 32… Wiring board, 33… Holder, 35… Connector, 36… Fixed plate, 36fa… First surface, 36fb… Second surface, 36p1… First edge, 36p2… Second edge, 36s… Side surface, 36s1… Outer peripheral surface, 36s2… Inner peripheral surface, 36t… Edge, 38… Cover, 41, 41a… Nozzle plate, 41fa… Surface, 41s2… Outer peripheral surface, 42… Communication plate, 43… Pressure chamber substrate, 44… Diaphragm, 45… Compliance substrate, 46… Protection part, 47… Housing part, 51… Mold, 51a… First mold, 51b… Second mold, 62… Adhesive, 62a… First adhesive, 62b… Second adhesive, 100… Liquid injection device, 241… Carrier, 242… Endless belt, 251… Support, 252… Liquid injection head, 253… Mounting hole, 300… Flow path structure, 311… Substrate, 312a… First supply protrusion, 312b… Second supply protrusion, 313a… First discharge protrusion, 313b… Second discharge protrusion, 331… Recess, 332… Ink hole, 333… Wiring hole, 334… Flange, 335… Screw hole, 337… Groove, 338, 338a… Outer peripheral wall, 339… Bottom surface, 339a… Inner bottom surface, 361… Exposure opening, 381… Hole for protrusion, 382… Opening, 451… Sealing film, 452… Support plate, C… Pressure chamber, Da… First discharge flow path, Da_out… First discharge port, Db… Second discharge flow path, Db_out… Second discharge port, E… Driving element, H1~H4, Hn… Head chip, Lh1… Dimension, Lh2… Dimension, Lp… Dimension, Lr… Dimension, Ly… Water-repellent film, N… Nozzle, Qa… First liquid injection part, Qb… Second liquid injection part, R1… Communication flow path, R2… Supply flow path, Ra… First liquid storage chamber, Ra_in… Supply hole, Ra_out… Discharge hole, Rb… Second liquid storage chamber, Rb_in… Supply hole, Rb_out… Discharge hole, Rh… Hydrophilic region, Rh1… First region, Rh2… Second region, Rh3… Hydrophilic region, Rp1, Rp2… Region, Rt… Water-repellent region, Rt3… Nozzle formation region, Sa… First supply flow path, Sa_in… First supply port, Sb… Second supply flow path, Sb_in… Second supply port, Su, Su1~Su5… Substrate

Claims

1. A head chip that injects liquid in an injection direction, A fixing plate having a first surface facing the injection direction, a second surface that is the surface to which the head chip is fixed and is opposite to the first surface, and a side surface connecting the first surface and the second surface, A holder that holds the head chip between the head chip and the fixing plate, and comprising In a plan view seen toward the first surface, the first surface includes a water-repellent region having water repellency and a hydrophilic region disposed between the water-repellent region and the side surface and having lower water repellency than the water-repellent region, A part of a mold disposed between the side surface and at least one of the head chip and the holder is adhered to the hydrophilic region of the first surface. A liquid injection head, characterized in that.

2. The hydrophilic region of the first surface is disposed between the water-repellent region and the side surface so as to be adjacent to the side surface. The liquid injection head according to claim 1, characterized in that.

3. The side surface has water repellency. The liquid injection head according to claim 1, characterized in that.

4. A part of the mold is adhered to the second surface. The liquid injection head according to claim 1, characterized in that.

5. The side surface includes an outer peripheral surface of the fixing plate, The mold includes a first mold disposed between the outer peripheral surface of the fixing plate and the holder, The hydrophilic region of the first surface includes a first region disposed along the outer peripheral surface of the fixing plate, A part of the first mold is adhered to the first region. The liquid injection head according to claim 1, characterized in that.

6. In the arrangement direction of the side surface and the first region adjacent to each other in the plan view, the dimension of the first region is larger than the thickness of the fixing plate. The liquid ejection head according to claim 5, characterized in that.

7. In the arrangement direction of the side surface and the first region adjacent to each other in the plan view, the dimension of the first region is smaller than the dimension of the portion of the first mold disposed between the side surface and the holder. The liquid ejection head according to claim 5, characterized in that.

8. The second surface and the holder are fixed by an adhesive disposed between the second surface and the holder. A part of the first mold is adhered to the second surface. The liquid resistance of the first mold is higher than the liquid resistance of the adhesive. The liquid ejection head according to claim 5, characterized in that.

9. The second surface and the holder are fixed by an adhesive disposed between the second surface and the holder. A part of the first mold is not adhered to the second surface. The liquid resistance of the first mold is higher than the liquid resistance of the adhesive. The liquid ejection head according to claim 5, characterized in that.

10. The holder has an outer peripheral wall fixed to the second surface by an adhesive on the bottom surface facing the ejection direction. A groove is formed in the bottom surface of the outer peripheral wall at a position overlapping the outer peripheral surface of the fixing plate in the plan view. A part of the first mold is disposed inside the groove. The liquid ejection head according to claim 5, characterized in that.

11. The head chip includes a nozzle plate having a plurality of nozzles for ejecting liquid. The fixing plate has an exposure opening that exposes the nozzle plate to the outside. The side surface includes an inner peripheral surface that defines the exposure opening of the fixing plate. The mold includes a second mold disposed between the inner peripheral surface and the nozzle plate. The hydrophilic region of the first surface includes a second region disposed along the inner peripheral surface. A part of the second mold is adhered to the second region. The liquid ejection head according to claim 1, characterized in that.

12. In the arrangement direction of the side surface and the second region adjacent to each other in the plan view, the dimension of the second region is larger than the thickness of the fixing plate. The liquid ejection head according to claim 11, characterized in that.

13. In the arrangement direction of the side surface and the second region adjacent to each other in the plan view, the dimension of the second region is smaller than the dimension of the portion of the second mold disposed between the side surface and the nozzle plate. The liquid ejection head according to claim 11, characterized in that.

14. In the plan view, the surface of the nozzle plate has a water-repellent nozzle formation region where the plurality of nozzles are formed, and a hydrophilic region disposed between the outer peripheral surface of the nozzle plate and the nozzle formation region and having lower water repellency than the nozzle formation region. A part of the second mold is disposed in the hydrophilic region of the nozzle plate. The liquid ejection head according to claim 11, characterized in that.

15. The liquid ejection head according to any one of claims 1 to 14, A liquid storage unit that stores the liquid supplied to the liquid ejection head, A liquid ejection device, characterized by comprising.

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