JP2014172269A - Liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge head capable of easily evaluating water repellency of a discharge face thereof.SOLUTION: The liquid discharge head comprises a discharge port 11 for discharging liquid, a liquid flow path communicated with the discharge port and an energy generating element generating energy for discharging liquid. Further the liquid discharge head comprises: a substrate having the energy generating element on a first surface; and a flow path forming member that includes, on the first surface of the substrate, a wall structure of a flow path composing the discharge port and the liquid flow path, a recess portion 5 recessed from an upper surface of the wall structure of the flow path and a first island structure surrounded by the recess portion, where a water repellent surface 8 is formed on an upper surface of the flow path forming member.

Description

  The present invention relates to a liquid discharge head.

  2. Related Art Inkjet printers that eject ink are widely known as recording apparatuses that perform a recording operation by ejecting liquid. A liquid discharge head used in such a recording apparatus has a substrate and a flow path forming member provided on the substrate. The flow path forming member is provided with a discharge port penetrating from the substrate side toward the outermost layer of the flow path forming member, and the liquid is discharged to the printing material through the discharge port.

  Here, the outermost layer of the flow path forming member is desirably a surface to which liquid is difficult to adhere, and is a surface having high water repellency in many liquid ejection heads. This is because if the liquid adheres to the surface in the vicinity of the discharge port, the ejection direction from the discharge port may be disturbed, leading to a decrease in recording quality.

  Therefore, in order to maintain the recording quality of the liquid discharge head, it is important to determine the superiority or inferiority of the water repellency of the outermost layer in addition to forming the water repellency of the outermost layer high. Patent Document 1 is disclosed as a method for evaluating water repellency in the liquid discharge head. In Patent Document 1, with the outermost layer facing upward, liquid is dropped on the surface of the outermost layer, and an image of the liquid side surface is obtained by a camera prepared in the side surface direction of the liquid, that is, the side surface direction of the liquid ejection head. Thus, a method for measuring the contact angle of a liquid is shown.

Japanese Patent Laid-Open No. 2002-21981

  However, in the method described in Patent Document 1, it is necessary to observe from the side of the liquid ejection head in order to obtain an image of the liquid side, and in the case of a liquid ejection head having an obstacle between the camera and the liquid, observation is performed. May become difficult. In the liquid discharge head, the surrounding head constituent member is relatively higher than the outermost layer and protrudes in the direction of the printed material so that physical damage is not applied to the outermost layer of the flow path forming member. Furthermore, the circumference | surroundings of the board | substrate containing an outermost layer were covered with the sealing agent, and the sealing agent sometimes became a position higher than the outermost layer. Since these surrounding head constituent members and sealants become obstacles in the measurement, the liquid discharge head may need to be disassembled or broken in order to measure in the form of the liquid discharge head. . Therefore, in the method of Patent Document 1, it is practically difficult to evaluate the water repellency after the head formation, and furthermore, it is difficult to confirm the change in water repellency according to the head usage history on demand.

  Accordingly, an object of the present invention is to provide a liquid ejection head that can easily evaluate the water repellency of the ejection surface. A more preferred object of the present invention is to provide a liquid ejection head with high recording quality, which can easily evaluate the water repellency of the ejection surface without disassembling or destroying the liquid ejection head.

  One aspect of the present invention is a liquid discharge head that includes a discharge port that discharges a liquid, a liquid flow path that communicates with the discharge port, and an energy generation element that generates energy for discharging the liquid. A substrate having the energy generating element on the first surface side, a flow channel wall structure portion forming the discharge port and the liquid flow channel on the first surface of the substrate, and the flow channel wall structure portion A liquid discharge head having a flow path forming member including a concave portion recessed from the upper surface of the liquid crystal and a first island structure portion surrounded by the concave portion, and having a water repellent surface formed on the upper surface of the flow path forming member. .

  Further, according to one aspect of the present invention, the liquid discharge head, a droplet dropping mechanism that drops liquid on the upper surface of the first island structure portion, and a liquid observation mechanism that observes the state of the liquid dropped on the first island structure portion And a liquid ejecting apparatus.

  One embodiment of the present invention is a method for determining water repellency on an upper surface of the first island structure portion by using the liquid discharge head to drop a liquid onto the upper surface of the first island structure portion.

According to one embodiment of the present invention, a substrate having an energy generating element that generates energy for discharging a liquid on a first surface side, and formed on the first surface of the substrate to discharge the liquid. And a flow path wall structure that forms a liquid flow path that communicates with the discharge port, a recess that is recessed from the upper surface of the flow path wall structure, and a first island structure that is surrounded by the recess. A liquid discharge head manufacturing method, wherein a water repellent surface is formed on an upper surface of the flow path forming member,
(1) forming a flow path mold pattern serving as a mold material for the liquid flow path on the first surface of the substrate;
(2) placing a coating resin material and a water repellent material on the substrate and the flow path pattern;
(3) The coating resin material is subjected to an exposure process to form a latent image of the discharge port and the recess, and subsequently subjected to a development process, whereby the flow path wall structure portion, the recess, and the first island structure Forming a part;
A method of manufacturing a liquid discharge head having

  According to the present invention, it is possible to provide a liquid discharge head that can easily evaluate the water repellency of the discharge surface. More preferably, according to the present invention, it is possible to easily evaluate the water repellency of the ejection surface without disassembling or destroying the liquid ejection head, and it is possible to provide a liquid ejection head with high recording quality.

FIG. 3 is a perspective view, a schematic plan view, and a schematic cross-sectional view illustrating a configuration example of a liquid ejection head according to an embodiment of the present invention. It is a typical cross-sectional process drawing for demonstrating the manufacturing process example of the liquid discharge head which concerns on this embodiment. FIG. 5 is a schematic cross-sectional view illustrating a water repellency superiority / inferiority determination method in the liquid ejection head according to the present embodiment. FIG. 2 is a schematic plan view showing a form of a liquid ejection head according to the present embodiment. It is a typical cross-sectional process drawing for demonstrating the manufacturing process example of the liquid discharge head which concerns on this embodiment. FIG. 2 is a schematic plan view showing a form of a liquid ejection head according to the present embodiment. FIG. 5 is a schematic cross-sectional view illustrating a water repellency superiority / inferiority determination method in the liquid ejection head according to the present embodiment. FIG. 2 is a schematic plan view showing a form of a liquid ejection head according to the present embodiment. It is a typical cross-sectional process drawing for demonstrating the manufacturing process example of the liquid discharge head which concerns on this embodiment. FIG. 5 is a schematic cross-sectional view illustrating a water repellency superiority / inferiority determination method in the liquid ejection head according to the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The liquid discharge head can be mounted on an apparatus such as a printer, a copying machine, a facsimile having a communication system, a word processor having a printer unit, or an industrial recording apparatus combined with various processing apparatuses. By using this liquid discharge head, recording can be performed on various recording media such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramics.

  “Recording” used in this specification means not only giving an image having a meaning such as a character or a figure to a recording medium but also giving an image having no meaning such as a pattern. I decided to.

  Furthermore, “liquid” is to be interpreted widely, and is applied to a recording medium to form an image, pattern, pattern, etc., process the recording medium, or process ink or recording medium. It shall refer to the liquid provided. Examples of the treatment of the ink or the recording medium include, for example, improvement in fixing property due to solidification or insolubilization of the coloring material in the ink applied to the recording medium, improvement in recording quality or color development, and improvement in image durability. I shall say that.

  FIG. 1A is a schematic perspective view of the liquid discharge head according to the present embodiment. FIG.1 (b) is the typical top view observed from the upper direction of Fig.1 (a). 1C-1 is a cross-sectional view of the liquid discharge head of FIG. 1A cut along the line AA ′, and FIG. 1C-2 is the liquid discharge head of FIG. It is sectional drawing cut | disconnected by BB 'line.

  The liquid discharge head of this embodiment includes a substrate 10 having an energy generating element 14 on the first surface side. As shown in FIG. 1C-1, the insulating layer 16, the energy generating element 14, and the protective layer 15 are formed on the first surface of the substrate 10. A flow path forming member 6 is provided on the protective layer 15. In the present embodiment, the flow path forming member includes a flow path wall structure portion 7 that forms a discharge port 11 that discharges liquid and a liquid flow path 13 that communicates with the discharge port 11, and an upper surface ( A recess 5 that is recessed from the discharge surface) and an island structure portion 7 ′ surrounded by the recess 5. Reference numeral 1 denotes an island structure constituent part composed of a recess 5 and an island structure surrounded by the recess.

  A water repellent surface is formed on the upper surface of the flow path forming member. That is, the water repellent surface 8 is formed on the upper surface of the channel wall structure portion, and the water repellent surface 8 'is formed on the upper surface of the island structure portion 7'. The island structure portion 7 ′ is surrounded by a recessed portion (also referred to as a recessed structure) 5 that is recessed from the upper surface (discharge surface) of the flow path wall structure portion 7 toward the substrate. The water repellent surface 8 ′ on the upper surface of the island structure portion preferably has the same level of water repellency as the water repellent surface 8 on the upper surface of the flow path wall structure portion.

  The flow path forming member 6 includes a discharge port 11 that discharges liquid using energy generated by the energy generating element 14 formed on the first surface side of the substrate 10, and a liquid flow path that communicates with the discharge port 11. 13. The liquid channel 13 is formed by the inner wall (side wall, upper wall) of the channel forming member 6 and the protective layer 15 formed on the substrate 10.

  Further, the substrate 10 is provided with a supply port 17 provided through the substrate 10 in order to supply the liquid to the liquid flow path 13. Further, on the first surface side of the substrate 10, an electrode pad 12 that is electrically connected to the outside is formed.

  Further, in such a liquid discharge head, a support substrate of a liquid discharge unit (not shown) made of alumina or the like is connected to a second surface side that is a surface opposite to the first surface of the substrate 10. . The liquid is supplied from the support substrate of the liquid discharge unit to the supply port 17, and the liquid is supplied from the supply port 17 to the liquid channel 13. The liquid transported to the liquid flow path 13 causes film boiling due to the thermal energy generated by the energy generating element 14, and a recording operation is performed by ejecting droplets from the ejection port 11.

  A wiring layer (not shown) for driving the energy generating element 14 is provided on the first surface side of the substrate 10. In addition, at least one insulating layer 16 is provided below the energy generating element 14 and the wiring layer. Further, at least one protective layer 15 is provided above the energy generating element 14 and the wiring layer, and the energy generating element 14 and the wiring layer are protected from contact with the liquid by the protective layer 15.

  The liquid discharge head according to this embodiment can easily evaluate the water repellency of the discharge surface. Specifically, when a liquid is dropped from above toward the island structure component 1, when the water repellency of the top surface of the island structure is high, the dropped liquid is repelled on the top surface and pulled to the recess 5, resulting in the island No liquid remains on the top surface of the structure. On the other hand, when the water repellency of the upper surface of the island structure portion is reduced and the difference in water repellency between the upper surface and the side wall of the recess 5 is reduced, the dropped liquid remains on the upper surface. Therefore, the liquid discharge head according to the present embodiment can easily evaluate the water repellency by attaching the liquid to the island structure component 1.

  Therefore, a liquid discharge apparatus including the liquid discharge head according to the present embodiment, a liquid drop mechanism for dropping liquid on the upper surface of the island structure, and a liquid observation mechanism for observing the state of the liquid dropped on the island structure. Accordingly, the water repellency of the discharge surface of the liquid discharge head can be easily determined in a timely manner.

  Hereinafter, an example of a process for manufacturing the liquid discharge head according to the present embodiment will be described with reference to FIG. In addition, this invention is not limited to the following embodiment.

  FIG. 2 is a schematic view showing a manufacturing process in the cross-sectional view taken along the line A-A ′ and the cross-sectional view taken along the line B-B ′ of the liquid discharge head shown in FIG.

  First, as shown in FIGS. 2A-1 and 2A-2, a substrate 10 having an insulating layer 16, an energy generating element 14, and a protective layer 15 on the first surface side is prepared.

  Specifically, for example, first, a silicon substrate 10 having a crystal orientation (100) is prepared. A laminated structure including an insulating layer 16 made of silicon oxide, an energy generating element 14 made of tantalum silicon nitride, and a protective layer 15 made of a silicon nitride film is formed on the first surface side of the silicon substrate 10. For the formation of the insulating layer 16, a growth method by thermal oxidation can be used. The energy generating element 14 and the protective layer 15 can be formed by patterning a film formed by sputtering using a photolithography method, a dry etching method, a wet etching method, or the like, thereby obtaining a desired shape.

  Next, as shown in FIGS. 2 (b-1) and (b-2), a flow path pattern 18 as a liquid flow path mold material is formed on the protective layer 15.

  Specifically, for example, first, a positive photosensitive resin material as a soluble resin is applied onto the protective layer 15 by spin coating, exposed and developed, and the flow path pattern 18 has a thickness of 14 μm. Form. As the positive photosensitive resin material, a material that has little compatibility with an organic resin material to be coated in a subsequent process and can be easily removed in the subsequent process is desirable. For example, a thermoplastic resin can be used.

  Next, as shown in FIGS. 2 (c-1) and (c-2), the coating resin material 19 is disposed on the flow path pattern 18, and the water repellent material 20 is disposed on the coating resin material 19. Deploy.

  Specifically, for example, a negative photosensitive resin material is arranged as the coating resin material 19 on the flow path pattern 18, and the water repellent material 20 is laminated thereon. The coating resin material 19 is required to have a low compatibility with the flow path pattern 18, as well as corrosion resistance to liquid, adhesion to the substrate, strength against external impact, and patterning accuracy. Specifically, as the coating resin material 19, for example, a thermoplastic resin made of epoxy resin, polyether amide resin, polyimide resin, polycarbonate resin, polyester resin, or the like can be used. As the water repellent material 20, a material having high water repellency with respect to a liquid and whose water repellency hardly changes with time is desirable. Specifically, as the water repellent material 20, for example, a photosensitive resin material, a thermosetting resin, or a fluorinated organic resin can be used. As the photosensitive resin material of the water repellent material 20, for example, a negative type can be used.

  Next, as shown in FIGS. 2 (d-1) and 2 (d-2), at least the flow path wall structure portion 7 constituting the discharge port 11 and the upper surface of the flow path wall structure portion 7 using a photolithography method. Then, a flow path forming member 6 having a recess 5 directed from the substrate to the substrate and an island structure portion 7 ′ surrounded by the recess 5 is formed. The concave portion 5 is formed from the upper surface of the flow path wall structure portion 7 until it reaches the substrate or the protective layer 15.

  Specifically, the coating resin material 19 is subjected to exposure processing / development processing using a photolithographic method, and the coating resin material 19 is partially removed by performing a thermosetting process as necessary, so that the discharge port 11 can be removed. And the recessed part 5 is formed. More specifically, a latent image corresponding to the discharge port 11 and the concave portion 5 is formed on the coating resin material 19, and the latent image is developed to thereby form the flow path wall structure portion 7 and the concave portion constituting the discharge port 11. A flow path forming member having an island structure portion 7 ′ surrounded by 5 is formed. When a negative photosensitive resin is used as the coating resin material 19, the exposed portion is cured, and the flow path wall structure portion 7 and the island structure portion 7 ′ constituting the liquid flow path 13 and the discharge port 11 are formed. It is formed.

  The flow path forming member has a flow path wall structure portion 7 constituting the liquid flow path 13 and the discharge port 11 and an island structure portion 7 ′ surrounded by the recess 5. The upper surface of the flow path wall structure portion 7 becomes a discharge surface, and the upper surface of the flow path forming member including the discharge surface is subjected to a water repellent treatment to form a water repellent surface. That is, a water repellent surface is formed on the upper surface of the channel wall structure 7 and the upper surface of the island structure 7 ′. In FIG. 2D-2, reference numeral 8 indicates a water repellent surface formed on the upper surface of the flow path wall structure portion 7, and reference numeral 8 'indicates a water repellent surface formed on the upper surface of the island structure portion 7'. In the present embodiment, the water repellent surface 8 on the top surface of the flow path wall structure 7 and the water repellent surface 8 ′ on the top surface of the island structure 7 ′ are formed using the same material and under the same processing conditions, and therefore have the same water repellency. . However, as will be described later, by changing processing conditions such as exposure, the water repellency of the water repellent surface 8 on the upper surface of the channel wall structure and the water repellent surface 8 ′ of the upper surface of the island structure can be adjusted. Aqueous properties can be imparted. Note that the material used for the water-repellent treatment includes a liquid such as a resin material and a gas such as a gas.

  In this embodiment, the water repellent surface 8 on the upper surface of the flow path wall structure and the water repellent surface 8 ′ on the upper surface of the island structure are formed under the same exposure processing conditions, development processing conditions, and thermosetting processing conditions. . Therefore, the water repellent surface 8 ′ on the top surface of the island structure portion has the same level of water repellency as the water repellent surface 8 on the top surface of the channel wall structure portion. In the present invention, the same level of water repellency means that in the dynamic receding contact angle measurement using pure water, the dynamic receding contact angle on the water repellent surface 8 ′ on the upper surface of the island structure portion is the repellency on the upper surface of the channel wall structure portion. It is included within ± 3 ° of the dynamic receding contact angle on the water surface 8. The dynamic receding contact angle in the present invention is defined as the dynamic receding contact angle of pure water. The dynamic receding contact angle of pure water can be measured by, for example, a method of photographing a droplet with a CCD camera and analyzing the image. Specifically, 0.5 μL of pure water is dropped on the surface of the measurement object and attached to the surface, and the dynamic receding contact angle when the attached pure water contracts is measured.

  Next, as shown in FIGS. 2E-1 and 2E-2, a supply port 17 penetrating the substrate 10 is formed.

  Specifically, for example, first, the protective resist 21 is applied on the substrate by spin coating. This protective resist is desirably a material that has alkali resistance and can be easily removed by wet treatment. For example, cyclized rubber can be used. Subsequently, a non-through hole (not shown) is formed in the substrate 10 from one surface of the substrate 10 by laser using laser ablation processing. Thereafter, the supply port 17 having a silicon (111) surface can be formed by wet etching using a strong alkaline liquid.

  Next, the insulating layer 16 and the protective layer 15 exposed at the supply port 17 are partially removed, and the flow path pattern 18 is further removed.

Specifically, a part of the insulating layer 16 and the protective layer 15 covering the upper side of the supply port 17 is removed by wet etching using hydrofluoric acid and dry etching in a gas atmosphere containing CF ₄ , O ₂ , and N _2. To do. Thereafter, the protective resist 21 made of cyclized rubber is removed by wet treatment, and then the flow path pattern 18 is removed by UV irradiation and wet treatment.

  Through the above steps, as shown in FIGS. 2 (f-1) and 2 (f-2), the island structure part surrounded by the flow path wall structure part 7 and the concave part 5 constituting the discharge port 11 and the liquid flow path 13 A liquid discharge head including a flow path forming member having 7 ′ is completed.

  In the liquid discharge head formed by the above manufacturing method, the water repellency of the upper surface of the island structure portion 7 ′ is higher than the water repellency of the side surface of the flow path wall structure portion. Moreover, in the dynamic receding contact angle measurement using pure water, the dynamic receding contact angle with respect to pure water on the water repellent surface of the island structure portion 7 ′ is larger than the dynamic receding contact angle on the side surface of the channel wall structure portion. It is preferably 10 ° or higher, more preferably 15 ° or higher, and further preferably 20 ° or higher.

  FIG. 3 shows a cross-sectional view of the obtained liquid discharge head when the liquid 22 is dropped from above the island structure component 1 toward the water repellent surface 8 ′ and the recess 5. FIG. 3A is a model diagram when the water repellent surface 8 ′ on the top surface of the island structure portion 7 ′ has low water repellency, and FIG. 3B shows the water repellent surface 8 ′ on the top surface of the island structure portion 7 ′. It is a model figure when it has high water repellency. When the water repellent surface 8 ′ on the top surface of the island structure 7 ′ has high water repellency, the dropped liquid 22 is repelled by the water repellent surface 8 ′ and pulled by the recess 5 having a side wall with low water repellency. The liquid 22 does not remain on the water surface 8 ′. Further, when the water repellency of the water repellent surface 8 ′ is lowered and the difference in water repellency between the water repellent surface 8 ′ and the side wall of the recess 5 is reduced, the dropped liquid 22 remains on the water repellent surface 8 ′. For example, when the dynamic receding contact angle with respect to pure water of the water repellent surface 8 ′ is 90 ° and the dynamic receding contact angle with respect to pure water on the side surface of the recess is 60 °, the liquid 22 does not remain on the water repellent surface 8 ′. .

  Therefore, in the liquid discharge head of this embodiment, it is possible to determine the superiority or inferiority of the water repellency by dropping the liquid onto the island structure portion 7 ′ and observing the presence or absence of the liquid on the water repellent surface 8 ′. With this method, it is possible to easily evaluate the superiority or inferiority of water repellency without disassembling and destroying the head and measuring the dynamic receding contact angle of the liquid, and it is possible to provide a liquid ejection head with high recording quality.

In addition, the shape of the island structure portion is not particularly limited, and examples thereof include a cylindrical shape, an elliptical column shape, a polygonal column shape such as a triangular column shape, a quadrangular column shape, and the like, and various other shapes may be used. . Moreover, the island structure component may include a plurality of island structures. The shape, dimensions, and the like of the island structure portion are not particularly limited and can be appropriately adjusted in consideration of the effects of the present invention. Further, the shape and dimensions of the recess 5 are not particularly limited and can be appropriately adjusted in consideration of the effects of the present invention. Other various shapes may be used. The area of the upper surface of the island structure is, for example, 50 [mu] m ² or more, preferably at 50 [mu] m ² or more 50000 ² below.

  In addition, as shown to Fig.8 (a), (b), the area | regions 32, 33, and 34 from which water repellency differs may be contained in one island structure. Moreover, as shown in FIG. 4, the island structure part may be provided with a plurality of island structure parts, and the top surface area of each island structure part may be different.

(Example 1)
In this example, the process of manufacturing the liquid discharge head of this embodiment will be specifically described with reference to FIG. FIG. 5 is a schematic view showing a manufacturing process in a cross-sectional view taken along the line AA ′ and a cross-sectional view taken along the line BB ′ of the liquid discharge head shown in FIG.

  First, as shown in FIGS. 5A-1 and 5A-2, a silicon (100) substrate 10 is prepared, an insulating layer 16 made of silicon oxide on one surface, and an energy generating element made of tantalum silicon nitride. 14. A laminated structure including the protective layer 15 made of a silicon nitride film was formed. For the formation of the insulating layer 16, a growth method by thermal oxidation was used. The energy generating element 14 and the protective layer 15 were formed by sputtering, and patterned into a desired shape using photolithography, dry etching, and wet etching.

  Next, as shown in FIGS. 5B-1 and B-2, a flow path pattern 18 was formed on the protective layer 15. The flow path pattern 18 was first formed by applying a soluble positive photosensitive resin material onto a substrate by spin coating, exposing and developing the material, and having a thickness of 14 μm. The material of the flow path pattern 18 is preferably a material that has little compatibility with the organic resin material to be coated in a subsequent process and can be easily removed in the subsequent process, and a thermoplastic resin is used.

  Next, as shown in FIGS. 5 (c-1) and (c-2), a negative photosensitive resin material is applied on the flow path pattern 18 as the coating resin material 19, and the coating resin material 19 A water repellent material 20 was laminated on the substrate.

  Next, as shown in FIGS. 5D-1 and 5D-2, the coating resin material is partially removed by exposure / development / thermosetting using a photolithography method, and the discharge port 11 is removed. And recesses 5 are formed, and the coating resin material is partially cured to form island structure components having flow path wall structures 7 and a plurality of island structures (7'a, 7'b, 7'c). did.

  Here, reference numeral 8′a indicates the water repellent surface on the upper surface of the first island structure portion 7′a, reference numeral 8′b indicates the water repellent surface on the upper surface of the second island structure portion 7′b, and reference numeral 8′c indicates It refers to the water repellent surface of the upper surface of the third island structure portion 7'c. In the present embodiment, the water repellent surface 8'a on the top surface of the first island structure portion 7'a, the water repellent surface 8'b on the top surface of the second island structure portion 7'b, and the water repellent surface on the top surface of the third island structure portion 7'c. 8'c was formed to have different water repellency. Further, the water repellent surface on the upper surface of the flow path wall structure 7 was formed to be at the same level as the water repellency of the water repellent surface of at least one island structure. That is, in the dynamic receding contact angle measurement using pure water, the dynamic receding contact angle on the water repellent surface 8′a on the upper surface of the first island structure portion 7′a is the movement on the water repellent surface 8 on the upper surface of the channel wall structure portion 7. It was formed so as to be included within ± 3 ° of the setback contact angle. Specifically, the exposure amount for forming the flow path wall structure portion 7 and the exposure amount for forming the first island structure portion 7'a are set to the same amount. Further, the water repellent surface 8'b on the upper surface of the second island structure portion 7'b and the water repellent surface 8'c on the upper surface of the third island structure portion 7'c are connected to the water repellent surface 8 'on the upper surface of the first island structure portion 7'a. In order to produce a water repellency difference with respect to a, the exposure amount for forming the second island structure portion 7′b and the third island structure portion 7′c was changed. More specifically, the water repellent surface 8'a on the top surface of the first island structure portion 7'a, the water repellent surface 8'b on the top surface of the second island structure portion 7'b, and the top surface of the third island structure portion 7'c. It formed so that water-repellent intensity might become high in order of water surface 8'c. The water repellency on the upper surface of the first island structure portion and the water repellency on the upper surface of the second island structure portion have an angle difference of, for example, 5 ° to 15 ° in the dynamic receding contact angle of pure water. Further, the water repellency on the upper surface of the second island structure portion and the water repellency on the upper surface of the third island structure portion have an angle difference of, for example, 5 ° to 15 ° in the dynamic receding contact angle measurement of pure water.

  Note that gradation photomasks having different transmittances can be used as exposure amount adjusting means, and multiple exposure can also be used.

  Next, as shown in FIGS. 5E-1 and 5E-2, a supply port 17 penetrating the substrate 10 was formed. First, the protective resist 21 was applied by spin coating. This protective resist is desirably a material that has alkali resistance and can be easily removed by wet treatment, and cyclized rubber was used. Next, a laser hole (not shown) that remains in the substrate 10 is formed from the second surface side of the substrate 10 using laser ablation processing, and then the silicon (111) surface is subjected to wet etching in a strong alkaline liquid. A supply port 17 having a shape including

Next, a part of the insulating layer 16 and the protective layer 15 covering the upper side of the supply port 17 was removed by hydrofluoric acid-based wet etching and dry etching in a gas atmosphere containing CF ₄ , O ₂ , and N ₂ . Thereafter, the protective resist 21 made of cyclized rubber was removed by wet treatment, and then the flow path pattern 18 was removed by UV irradiation and wet treatment.

  Through the above steps, as shown in FIGS. 5 (f-1), (f-2), and FIG. 6, the flow path wall structure 7, the recess 5, and a plurality of island structures (7 ′) surrounded by the recess 5 A liquid discharge head provided with a flow path forming member including an island structure component having a, 7′b, 7′c) was obtained.

  As shown in the above manufacturing method, the water repellency of the upper surfaces of the island structures (7'a, 7'b, 7'c) could be changed. Further, the side walls of the island structure portion and the recesses had low water repellency compared to the upper surface of the island structure portion (7'a, 7'b, 7'c) and the upper surface of the flow path wall structure portion.

  FIG. 7 shows a cross-sectional view of the liquid discharge head when the liquid 22 is dropped from above the island structures (7'a, 7'b, 7'c). The liquid 22 does not remain on the upper surface of the first island structure portion 7′a having the highest water repellency and the upper surface of the second island structure portion 7′b having the next highest water repellency, and on the upper surface of the third island structure portion 7′c having the lowest water repellency. Left the liquid 22. The reason why the liquid does not remain when the water repellency is at a high level is that the liquid is repelled by the water repellent surface while being pulled by the recess outer peripheral side wall and the island structure side wall having low water repellency. The reason why the liquid remains when the water repellency is at a low level is that the difference in water repellency between the upper surface of the island structure and the outer peripheral side wall of the recess and the side wall of the island structure portion is small. For example, when the dynamic receding contact angle with respect to pure water is 90 ° on the upper surface of the island structure and 60 ° on the side surface of the island structure, the liquid 22 does not remain on the upper surface. Further, for example, when the top surface of the island structure is 70 ° and the side surface of the island structure portion is 60 °, the liquid 22 may remain on the top surface.

  In the case of the present embodiment, it has an island structure constituent portion having a plurality of island structures having upper surfaces with different water repellency strengths, and one of them has the same level of repellent properties as the upper surface (discharge surface) of the channel wall structure portion. It is formed with water strength. With this configuration, it is possible to easily evaluate the water repellency strength rank of the discharge surface of the flow path wall structure, and thus it is possible to easily determine the recording quality. Furthermore, since it is not necessary to disassemble and destroy the head and measure the dynamic receding contact angle of the liquid, it is possible to provide a liquid ejection head with high recording quality.

(Example 2)
In this example, the process of manufacturing the liquid ejection head of this embodiment will be specifically described with reference to FIG. FIG. 9 is a schematic view showing a manufacturing process in the cross-sectional view taken along the line AA ′ and the cross-sectional view taken along the line BB ′ of the liquid discharge head shown in FIG.

  First, as shown in FIGS. 9A-1 and 9A-2, a silicon (100) substrate 10 is prepared, an insulating layer 16 made of silicon oxide on one surface, and an energy generating element made of tantalum silicon nitride. 14. A laminated structure including the protective layer 15 made of a silicon nitride film was formed. For the formation of the insulating layer 16, a growth method by thermal oxidation was used. The energy generating element 14 and the protective layer 15 were formed by sputtering, and patterned into a desired shape using photolithography, dry etching, and wet etching.

  Next, as shown in FIGS. 9B-1 and 9B-2, the flow path pattern 18 was formed on the protective layer 15. The flow path pattern 18 was formed by first applying a soluble positive photosensitive resin material by spin coating, exposing and developing, and having a thickness of 14 μm. The material of the flow path pattern 18 is preferably a material that has little compatibility with the organic resin material to be coated in a subsequent process and can be easily removed in the subsequent process, and a thermoplastic resin is used. At this time, the film thickness adjustment pattern 18 ′ is formed around a region where a recess formed in a subsequent process is formed using the same material as the flow path pattern.

  Subsequently, as shown in FIGS. 9 (c-1) and (c-2), a negative photosensitive resin material is applied as the coating resin material 19 on the flow path pattern 18 and the film thickness adjustment pattern 18 ′. The water repellent material 20 was laminated on the coating resin material 19.

  Here, as shown in FIG. 9 (c-2), in the region where the film thickness adjustment pattern 18 'is disposed in the lower layer, the height of the upper surface of the coating resin material is high (lamination thickness is large). Further, in the region where the island structure is formed where the film thickness adjustment pattern 18 ′ is not disposed in the lower layer, the upper surface height of the coating resin material is higher than that in the region where the film thickness adjustment pattern 18 ′ is disposed in the lower layer. , It was low (lamination thickness was small). When the film thickness adjustment pattern 18 ′ is formed with a film thickness of 14 μm and the laminated structure of the coating resin material and the water repellent material is aimed at 25 μm, the film thickness adjustment pattern 18 ′ is formed as a region formed in the lower layer. A thickness difference of about 1 μm was generated between the non-existing regions.

  In addition, it is preferable that the height of the upper surface of an island structure part is 1-50 micrometers lower than the height of the side wall which comprises the outer periphery of a recessed part, and it is more preferable that it is 5-10 micrometers lower.

  Next, as shown in FIGS. 9D-1 and 9D-2, the coating resin material is partially removed by exposure, development, and thermosetting using a photolithography method, and the discharge port 11. And the recessed part 5 was formed, the coating resin material was partially hardened, and the flow path wall structure part 7 and the island structure part 7 'were formed. Further, by forming the channel wall structure 7 and the island structure 7 ′ under the same exposure / development / thermosetting conditions, the water repellency of the upper surface of the channel wall structure 7 and the repellency of the upper surface of the island structure 7 ′ are obtained. The aqueous properties were almost the same, and the difference was within ± 3 ° in the dynamic receding contact angle measurement of pure water.

  Further, the side wall of the film thickness adjustment pattern 18 ′ is exposed on the outer peripheral side wall of the recess 5.

  Next, as shown in FIGS. 9E-1 and 9E-2, a supply port 17 penetrating the substrate 10 was formed. First, the protective resist 21 was applied by spin coating. This protective resist is desirably a material that has alkali resistance and can be easily removed by wet treatment, and cyclized rubber was used. Next, a laser hole (not shown) that remains in the substrate 10 is formed from the second surface side of the substrate 10 using laser ablation processing, and then the silicon (111) surface is subjected to wet etching in a strong alkaline liquid. A supply port 17 having a shape including

Next, a part of the insulating layer 16 and the protective layer 15 covering the upper side of the supply port 17 was removed by hydrofluoric acid-based wet etching and dry etching in a gas atmosphere containing CF ₄ , O ₂ , and N ₂ . Thereafter, the protective resist 21 made of cyclized rubber was removed by wet treatment, and then the flow path pattern 18 and the film thickness adjustment pattern 18 ′ were removed by UV irradiation and wet treatment.

  Through the above steps, a liquid discharge head was fabricated as shown in FIGS. 9 (f-1) and 9 (f-2).

  In the liquid discharge head formed by the manufacturing method described above, the thickness of the island structure portion 1 is smaller by about 1 μm than the thickness of the side wall constituting the outer periphery of the recess 5 in the flow path wall structure portion 7.

  FIG. 10 shows a cross-sectional view of the liquid discharge head when the liquid 22 is dropped from above the island structure portion 7 ′ toward the upper surface of the island structure portion and toward the recess 5. FIG. 10A is a model diagram when the water repellency of the upper surface of the island structure portion is low, and FIG. 10B is a model when the water repellency of the upper surface of the island structure portion is maintained at a high level. FIG. When the water repellency of the upper surface of the island structure portion is at a high level, the dropped liquid 22 is repelled on the upper surface, and is pulled by the recessed sidewall and the island structure side wall having low water repellency. 22 does not remain. When the water repellency of the upper surface of the island structure portion deteriorates to a low level and the difference in water repellency between the upper surface and the side walls of the recess and the island structure portion is small, the dropped liquid 22 remains on the upper surface.

  Therefore, it is possible to determine the water repellency of the ejection surface by observing the presence or absence of liquid in the island structure component. With this method, it is possible to easily evaluate the superiority or inferiority of water repellency without disassembling and destroying the head and measuring the dynamic receding contact angle of the liquid, and it is possible to provide a liquid ejection head with high recording quality. Moreover, since the upper surface of the island structure portion is located at a position lower than the side wall that forms the outer periphery of the recess, it is possible to suppress destruction of the island structure due to physical contact from the outside.

1: Island structure component 5: Recess (dent structure)
6: Channel forming member 7: Channel wall structure 7 ': Island structure 8: Water repellent surface on the top surface of the channel wall structure 8': Water repellent surface on the top surface of the island structure 10: Substrate 11: Discharge port 13 : Liquid channel 14: Energy generating element 15: Protective layer 16: Insulating layer 17: Supply port 18: Channel pattern 19: Coating resin material 20: Water repellent material 21: Protective resist 22: Liquid

Claims (14)

A liquid discharge head having a discharge port for discharging a liquid, a liquid flow path communicating with the discharge port, and an energy generating element for generating energy for discharging the liquid,
A substrate having the energy generating element on the first surface side;
On the first surface of the substrate, the flow path wall structure part constituting the discharge port and the liquid flow path, the concave part recessed from the upper surface of the flow path wall structure part, and the first island structure surrounded by the concave part A flow path forming member including a portion,
Have
A liquid discharge head in which a water repellent surface is formed on an upper surface of the flow path forming member.   2. The liquid ejection head according to claim 1, wherein the water repellent surface formed on the upper surface of the first island structure portion has the same level of water repellency as the water repellent surface formed on the upper surface of the flow path wall structure portion.   In the dynamic receding contact angle measurement using pure water, the dynamic receding contact angle on the water repellent surface formed on the upper surface of the first island structure portion is the movement on the water repellent surface formed on the upper surface of the channel wall structure portion. The liquid discharge head according to claim 2, wherein the liquid discharge head is included within ± 3 ° of the target receding contact angle.   4. The liquid ejection head according to claim 2, wherein upper surfaces of the flow path wall structure portion and the first island structure portion are subjected to water repellent treatment using the same material.   The liquid discharge head according to claim 4, wherein the upper surface of the first island structure portion is formed under the same processing conditions as the upper surface of the flow path wall structure portion.   The liquid discharge head according to claim 1, wherein the flow path wall structure portion and the first island structure portion are formed using the same material.   In the dynamic receding contact angle measurement using pure water, the dynamic receding contact angle on the upper surface of the first island structure portion is 10 ° or more higher than the dynamic receding contact angle on the side surface of the flow path wall structure portion. The liquid discharge head according to any one of 1 to 6. The liquid discharge head according to claim 1, wherein an area of an upper surface of the first island structure portion is 50 μm ² or more.   The liquid discharge head according to claim 1, wherein the first island structure portion has a cylindrical shape, an elliptical columnar shape, or a polygonal columnar shape.   10. The liquid ejection head according to claim 1, wherein a height of an upper surface of the first island structure portion is lower than a height of a side wall constituting an outer periphery of the recess. The flow path forming member further includes at least one second island structure portion surrounded by the recess,
11. The liquid ejection head according to claim 1, wherein a water repellent surface formed on an upper surface of the second island structure portion has a water repellency different from a water repellent surface formed on an upper surface of the first island structure portion. .   12. A liquid discharge head according to claim 1, a liquid dropping mechanism for dropping liquid onto the upper surface of the first island structure, and liquid observation for observing the state of the liquid dropped on the first island structure. A liquid ejection device having a mechanism.   A method for discriminating water repellency on an upper surface of the first island structure portion by using the liquid discharge head according to claim 1, wherein a liquid is dropped on the upper surface of the first island structure portion. A substrate having, on the first surface side, an energy generating element that generates energy for discharging liquid;
From the upper surface of the flow path wall structure portion, the flow path wall structure portion is formed on the first surface of the substrate and forms a discharge port for discharging the liquid and a liquid flow channel communicating with the discharge port. A flow path forming member including a recessed portion that is recessed, and a first island structure portion surrounded by the recessed portion,
A liquid discharge head manufacturing method in which a water repellent surface is formed on the upper surface of the flow path forming member,
(1) forming a flow path mold pattern serving as a mold material for the liquid flow path on the first surface of the substrate;
(2) placing a coating resin material and a water repellent material on the substrate and the flow path pattern;
(3) The coating resin material is subjected to an exposure process to form a latent image of the discharge port and the recess, and subsequently subjected to a development process, whereby the flow path wall structure portion, the recess, and the first island structure Forming a part;
A method of manufacturing a liquid discharge head having

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