JP6447314B2 - Inkjet head manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing an inkjet head.

  Conventionally, an inkjet head of an inkjet recording apparatus that records various images by ejecting ink in a channel is known. An inkjet head having a hydrophilic portion is known.

  For example, in an ink jet head having an ejection part that can eject by exchanging two types of ink, the ejection port forming surface is made to be a water repellent surface or non-repellent depending on the appropriateness for each ink to be ejected or two mixed inks. An ink jet recording apparatus that selects whether to surface is known (see Patent Document 1).

  There is also known an ink jet head in which the periphery of the ejection port of an ink ejection nozzle in which the surface of the ink ejection surface of a nozzle plate (nozzle substrate) has been subjected to ink repellent treatment has been hydrophilized (see Patent Document 2). This ink jet head suppresses bending in the ink ejection direction due to scratches caused by cleaning.

  Also, energy is applied only to the nozzle discharge surface of the nozzle plate (nozzle substrate) to selectively form a water repellent film, and the second energy after the water repellent film forming step is applied while other than the nozzle discharge surface (nozzle A manufacturing method of a nozzle plate including a hydrophilic film forming step of forming a hydrophilic film on an inner wall surface is known (see Patent Document 3).

JP 2006-240164 A JP 2001-121709 A JP 2011-68095 A

  However, for example, when a top plate is provided so as to surround the periphery of the nozzle substrate in order to protect the nozzle formed on the nozzle substrate, the inkjet head manufactured using the nozzle substrate described in Patent Documents 1 to 3 is a manufacturing process. In this case, there is a possibility that a defect may occur due to the remaining part of the protective layer used to flow to the portion of the nozzle substrate that is not water-repellent.

  Also, when ink is continuously ejected from the nozzle, if the ink is ejected continuously at a particularly high frequency, the amount of mist generated increases with the ejection frequency, so the ejection characteristics become unstable due to mist adhering to the nozzle ejection surface. I found out that As a result of intensive studies by the inventor, when a large liquid pool formed by large growth of mist adhering to the nozzle discharge surface flows into the nozzle hole, the amount of ink returning from the ink discharge surface to the nozzle hole becomes unstable, and the nozzle discharge It was found that the surface condition was changed, leading to significant discharge instability.

  An object of the present invention is to prevent a defect due to a remaining part of a protective layer in a manufacturing process and to obtain a stable ejection characteristic even during continuous ejection of ink.

In order to solve the above-mentioned problem, the invention described in claim 1
A protective layer applying step for applying a protective layer to the ink-repellent nozzle substrate;
A nozzle forming step of forming a nozzle on the nozzle substrate provided with the protective layer;
A protective layer peeling step of peeling the protective layer from the nozzle substrate on which the nozzle is formed;
A method of manufacturing an inkjet head having
After the protective layer peeling step, there is a parent ink step in which the entire surface of the nozzle substrate on the side where ink is ejected is subjected to a parent ink treatment.

The invention according to claim 2 is the method of manufacturing an ink jet head according to claim 1,
The method includes an assembly step of attaching to the nozzle substrate a top plate that surrounds the nozzle substrate and has a surface on which ink is ejected from the nozzle.

According to a third aspect of the present invention, in the method for manufacturing an ink jet head according to the second aspect,
The assembling step is performed in a state where the protective layer is applied to the ink-repellent treated portion of the nozzle substrate.

According to a fourth aspect of the present invention, in the method of manufacturing an ink jet head according to the second or third aspect,
In the parent ink process, at least a part of a surface of the top plate on which ink is ejected from the nozzle is subjected to a parent ink treatment together with the nozzle substrate.

Invention of Claim 5 is a manufacturing method of the inkjet head as described in any one of Claim 2 to 4,
A part of the top plate is
It is an area adjacent to the nozzle substrate in a surface located on the side of the top plate in the direction of ejecting ink from the nozzles.

The invention according to claim 6 is the method of manufacturing an ink-jet head according to any one of claims 2 to 5,
In the parent ink step, the degree of parent ink processing is changed such that the receding contact angle of the ink on the top plate changes from the outermost front surface to the side wall of the opening located inside the nozzle substrate.

The invention according to claim 7 is the method of manufacturing an inkjet head according to any one of claims 2 to 6,
The top plate has a recess structure,
The nozzle substrate is arranged at a position lower than the forefront surface of the top plate.

The invention according to claim 8 is the method of manufacturing an ink jet head according to claim 7,
The recess structure portion may be a tapered portion that is gently continuous from the outer periphery of the forefront surface to the side wall of the opening portion in which the nozzle substrate is located.
Invention of Claim 9 is the manufacturing method of the inkjet head as described in any one of Claim 2-8,
In the parent ink step, at least part of the top plate is protected by a protective material, and at least a surface of the nozzle substrate on the side where ink is ejected is subjected to parent ink treatment.
Invention of Claim 10 is the manufacturing method of the inkjet head as described in any one of Claim 1 to 9,
In the parent ink process, the main body of the inkjet head is surrounded and protected by a protective material.

Invention of Claim 11 in the manufacturing method of the inkjet head as described in any one of Claim 1 to 10 WHEREIN:
The nozzle substrate has an ink repellent layer,
The ink repellent layer has a lower binder layer having a binder component and an upper ink repellent component layer having an ink repellent component, and the concentration of the ink repellent component and the binder component is between the upper layer and the lower layer. It is changing continuously.

The invention of claim 12 is the manufacturing method of the ink-jet head according to any one of claims 1 to 11,
The protective layer is a protective film.

The invention of claim 13 is the manufacturing method of the ink-jet head according to any one of claims 1 to 12,
The parent ink process is a vacuum plasma process.

The invention according to claim 14 is the method of manufacturing an ink jet head according to claim 13 ,
The vacuum plasma treatment is dry etching.

  According to the present invention, it is possible to prevent a defect due to the remaining part of the protective layer in the manufacturing process and to obtain a stable discharge characteristic even during continuous discharge.

1 is a schematic configuration diagram illustrating an ink jet recording apparatus according to an embodiment of the present invention. It is a schematic perspective view of an inkjet head. It is sectional drawing of an actuator when cut | disconnecting by the cut surface of FIG. 1 is a cross-sectional view of an ink jet head of Example 1. FIG. FIG. 3 is a diagram showing a manufacturing flow of a manufacturing method in Example 1. 6 is a cross-sectional view of an ink jet head of Example 2. FIG. 6 is a cross-sectional view of an ink jet head of Example 3. FIG. 6 is a cross-sectional view of an inkjet head of Example 4. FIG. 6 is a cross-sectional view of an inkjet head of Example 5. FIG. 6 is a cross-sectional view of an inkjet head of Example 6. FIG. (A)-(d) is sectional drawing of each process of the parent ink process of the inkjet head of Example 7. FIG. 10 is a cross-sectional view of an ink jet head of Example 8. FIG. 10 is a cross-sectional view of an inkjet head of Example 9. FIG. 6 is a cross-sectional view of an inkjet head of Comparative Example 3. FIG. It is sectional drawing of the nozzle substrate which has a 2 layer structure ink repellent layer.

  Embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the illustrated example. In addition, in the following description, what has the same function and structure attaches | subjects the same code | symbol, and abbreviate | omits the description.

  The apparatus configuration of the present embodiment will be described with reference to FIGS. First, a schematic configuration of the ink jet recording apparatus 1000 of the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing an ink jet recording apparatus 1000. In addition, although the example which uses a line head is demonstrated below as an example about an inkjet recording device, it is not limited to this. For example, the present invention can also be applied to a scan-type inkjet recording apparatus that forms an image by scanning an inkjet head in a direction orthogonal to the conveyance direction of the recording medium. Moreover, although the example which provides each color of Y (yellow), M (magenta), C (cyan), and K (black) was described, it is not limited to this, A single color is applicable. For example, a configuration using only K (black) may be used.

  The ink jet recording apparatus 1000 includes a transport unit 200, an image forming unit 300, an ink supply unit 400, and a control unit 500. In the inkjet recording apparatus 1000, the image forming unit 300 forms an image with the ink supplied from the ink supply unit 400 on the recording medium P transported by the transport unit 200 based on the control of the control unit 500.

  The transport unit 200 holds the recording medium P on which image formation is performed and supplies the recording medium P to the image forming unit 300. The conveyance unit 200 includes an unwinding roll 210, rollers 220 and 230, a winding roll 240, and the like. The long recording medium P wound in a roll shape is unwound from the unwinding roll 210, conveyed while being supported by the rollers 220 and 230, and taken up by the winding roll 240.

  The image forming unit 300 discharges ink onto the recording medium P to form an image. The image forming unit 300 includes a plurality of line heads 310, a carriage 330 that holds the plurality of line heads 310, and the like. Moreover, when using the ink hardened | cured with an energy ray as an ink, it is preferable to provide the irradiation part 320 further.

  The line head 310 ejects ink onto the recording medium P conveyed to the conveyance unit 200 to form an image. The line head 310 is individually provided for each color of Y (yellow), M (magenta), C (cyan), and K (black). In FIG. 1, line heads 310 corresponding to the colors Y, M, C, and K are provided in order from the upstream in the conveyance direction of the recording medium P by the conveyance unit 200.

  The line head 310 of the present embodiment is provided on the carriage 330 with a length (width) that covers the entire recording medium P in a direction (width direction) substantially perpendicular to the conveyance direction of the recording medium P. That is, the ink jet recording apparatus 1000 is a one-pass line head type ink jet recording apparatus. The line head 310 is configured by arranging a plurality of inkjet heads 100 (see FIG. 2). Further, as shown, the carriage 330 may be provided with a carriage heater 330a to heat the ink.

  The irradiation unit 320 irradiates energy rays for curing the ink used in the inkjet recording apparatus 1000 after the ink is ejected onto the recording medium P. The irradiation unit 320 includes, for example, a fluorescent tube such as a low-pressure mercury lamp, and emits energy rays such as ultraviolet rays by causing the fluorescent tube to emit light. The irradiation unit 320 is provided downstream of the line head 310 in the conveyance direction of the recording medium P. The irradiation unit 320 cures the ink ejected on the recording medium P by irradiating the recording medium P after image formation with energy rays.

  As a fluorescent tube emitting ultraviolet rays, in addition to a low-pressure mercury lamp, a mercury lamp having an operating pressure of about several hundred Pa to 1 MPa, a light source usable as a germicidal lamp, a cold cathode tube, an ultraviolet laser light source, a metal halide lamp, a light emitting diode, etc. Is mentioned. Among these, a light source (for example, a light emitting diode) that can irradiate ultraviolet rays with higher illuminance and consumes less power is more desirable. The energy rays are not limited to ultraviolet rays, but may be any energy rays having a property of curing the ink according to the properties of the ink, and the light source is replaced according to the wavelength of the energy rays.

  The ink supply unit 400 includes an ink tank 410, a pump 420, an ink tube 430, a sub tank 440, an ink tube 450, a heater 460, and the like. The ink supply unit 400 stores ink, supplies the ink to the line head 310 of the image forming unit 300, and enables ink of each color to be ejected from each nozzle of the line head 310. The ink in the ink tank 410 is sent by the pump 420 to the sub tank 440 that adjusts the back pressure of the ink in the inkjet head 100 via the ink tube 430. The sub tank 440 is provided with a float sensor 440a, and a predetermined amount of ink is stored when the control unit 500 operates the pump 420 based on the liquid level position detection data by the float sensor 440a. The ink in the sub tank 440 is supplied to the inkjet head 100 through the ink tube 450. In this example, the configuration including the ink tank 410, the pump 420, the ink tube 430, the sub tank 440, the ink tube 450, and the heater 460 is illustrated, but the configuration is not limited thereto, and the configuration in which ink is supplied to the inkjet head 100. If so, various configurations can be applied.

  In the example shown in FIG. 1, the heater 460 is provided so as to cover all of the ink supply unit 400, but it is assumed that the heater 460 is provided individually on any of the members constituting the ink supply unit 400. Also good. Thus, the ink in the ink supply unit 400 is heated and kept warm, and the temperature of the ink is kept at a predetermined temperature or higher. The heater 460 is constituted by, for example, a heating wire or a heat transfer member, and is provided by covering each member constituting the ink supply unit 400 or being attached to the outer surface of the member constituting the ink supply unit 400. Yes.

  The ink used in the ink jet recording apparatus 1000 of the present embodiment is not particularly limited. For example, as in the evaluation of Examples 1 to 9 described later, the effect is high when using ink that contains particles and is likely to mist. .

The control unit 500 controls the operation of each unit of the inkjet recording apparatus 1000 and controls the entire operation. The control unit 500 includes a CPU (Central Processing Unit) and a ROM (Read Only).
Memory), RAM (Random Access Memory), and the like. In the control unit 500, various processing programs such as a system program stored in the ROM are read out and expanded in the RAM, and the program expanded in the RAM is executed by the CPU. Various control processes such as the ink supply process are executed.

  FIG. 2 is a schematic perspective view of the inkjet head 100. The ink jet head 100 includes an actuator 1, a housing 2, a top plate 3, and adhesive layers 4 and 5.

  A nozzle substrate 11 on which a large number of nozzles 11 a for discharging ink are arranged is bonded to the front surface of the actuator 1 (ink discharge side surface (front surface 1 a)).

  As the nozzle substrate 11, plastics such as polyalkylene terephthalate such as PET, polyimide, polyetherimide, polyetherketone, polyethersulfone, and polycarbonate can be used. Mist generated when ink is ejected adheres to the nozzle substrate.

  FIG. 3 is a cross-sectional view of the actuator 1 taken along the cutting plane S of FIG. The actuator 1 is a long piezoelectric ceramic substrate in which a large number of channels corresponding to each nozzle 11a are arranged in parallel, and is a member that generates a pressure change applied to ink. In addition, it is not limited to the actuator 1 in this embodiment described below, and it is not limited by the ejection method, such as a bend mode head or a method of ejecting ink by heating the ink to generate bubbles, The present invention can be applied to various discharge methods.

  Each channel 12 is cut into a straight and elongated groove shape by a diamond blade or the like, and the uncut piezoelectric ceramic constitutes a partition wall 13 between adjacent channels 12 and 12. The depth of each channel 12 gradually decreases as it goes to the right in FIG. 2, and finally disappears. A metal electrode (not shown) is formed on a part of the inner surface of the channel 12.

  Further, a cover substrate 14 made of a non-piezoelectric ceramic substrate or the like is bonded from above each channel 12. In the cover substrate 14, openings 14 a extending over all the channels 12 are formed at positions corresponding to the shallow groove portions of the respective channels 12, and a manifold 15 is provided so as to cover the openings 14 a. And a shallow groove portion of each channel 12, a common ink chamber 16 for distributing ink to each channel 12 is formed.

  The non-piezoelectric ceramic substrate is preferably selected from at least one of alumina, aluminum nitride, zirconia, silicon, silicon nitride, silicon carbide, quartz, and non-polarized PZT, and polarized even when the partition wall 13 is shear-deformed. The piezoelectric ceramic can be reliably supported.

  As a piezoelectric ceramic, a ceramic such as PZT, PLZT, etc., mainly a mixed microcrystal of PbOx, ZrOx, TiOx, a trace amount of metal oxide known as a softening agent or a hardening agent, such as Nb, Zn, Mg, Those containing oxides such as Sn, Ni, La, and Cr are preferable.

  PZT is lead zirconate titanate, which is preferable because it has a high packing density, a large piezoelectric constant, and good workability. When the temperature is lowered after firing, the crystal structure suddenly changes, and PZT becomes a collection of fine crystals in the form of dipoles in which atoms are displaced, one side is positive, and the other side is negative. These spontaneous polarizations are random in direction and cancel each other's polarity, so further polarization processing is required.

  In the polarization treatment, a thin plate of PZT is sandwiched between electrodes, immersed in silicon oil, and polarized by applying a high electric field of about 10 to 35 kV / cm. When a voltage is applied to the polarized PZT at a right angle to the polarization direction, the side wall is sheared and deformed in a diagonal shape in a diagonal direction by the piezoelectric sliding effect, and the volume of the ink chamber expands.

  Gold, silver, aluminum, palladium, nickel, tantalum, and titanium can be used as the material of the metal electrode, and gold and aluminum are particularly preferable from the viewpoint of electrical characteristics and workability. It is formed. Each metal electrode is drawn from the inside of each channel 12 to the upper surface on the rear side (right end in FIG. 3) of the actuator 1 through the shallow groove portion, and is electrically connected to the drive circuit by a signal line (not shown).

  When the driving voltage applied from the driving circuit is applied to the metal electrode in each channel 12, the actuator 1 shears and deforms the partition wall 13, thereby causing a pressure change in the channel 12. Ink is ejected from the nozzle 11a. The ink ejected from the nozzles 11a flies in the longitudinal direction of the channel 12 and lands on a recording material such as paper.

For example, acrylic, polycarbonate, polyetherimide, modified PPE, aluminum, stainless steel, or the like can be used for the top 3. However, mist generated when ink is ejected from the nozzles adheres to the top 3. Therefore, it is more preferable to use a stainless steel plate (for example, SUS316) from the viewpoint of ink resistance.
The top plate 3 is disposed so as to surround the nozzle substrate 11 and protects the periphery of the nozzle substrate 11. In the inkjet head 100, a flat space is formed around the nozzle substrate 11 by the top plate 3. An opening b having substantially the same shape as the nozzle surface of the actuator 1 is provided at a substantially central portion of the top plate 3, and the nozzle substrate 11 faces the opening b by fitting the actuator 1 into the opening b. Has been placed.
The top plate 3 and the actuator 1 are sealed with an adhesive layer 5.

  The adhesive layer 4 is preferably raised outward from the side surface of the top plate 3. Thereby, it is possible to further prevent the ink from penetrating to the back surface of the top plate 3. As the adhesive for the adhesive layers 4 and 5, for example, a combination of an epoxy compound and a curing agent is used.

  In the recovery operation of the nozzle that forcibly sucks ink from the nozzle 11 a of the actuator 1 using the suction cap, the surface (front surface 3 a) on which the top 3 opposes the recording medium is used as a cap receiving surface to suck ink. Ink can be sucked without damaging the nozzle substrate by closely contacting with a suction cap (not shown). In addition, it is preferable to have a function of maintaining the negative pressure inside the suction cap from the viewpoint of performing ink suction more efficiently.

Note that at least a part of the nozzle substrate and the top plate has a parent ink region. The parent ink region is a region in which the receding contact angle of water with respect to the region (measured by the expansion / contraction method) is 60 ° or less. Here, the “retracted contact angle” is a contact angle created on the surface of the substrate that has been once wetted with water after the water has once adhered to the substrate. The above-described parent ink region can be formed by, for example, a parent ink process such as a vacuum plasma process, and more specifically, dry etching or the like can be used. In the vacuum plasma treatment, an inkjet head chip, an inkjet head, etc. are placed in a vacuum chamber, and at least one selected from Ar, N ₂ and O ₂ or a mixed gas thereof is injected, and an external electromagnetic field causes a plasma state. In order to improve the surface etching property, a fluorine-based hydrocarbon gas such as CF ₄ may be used. In the ink jet of the present embodiment, it is preferable that O ₂ is contained in the gas.

In the ink jet recording apparatus 1000 equipped with the ink jet head 100, even if ink is continuously ejected at a high frequency, the mist generated during the continuous ejection is not collected as a liquid pool but attached to the ink-free nozzle substrate. A thin film is formed on the entire surface and a part of the top plate, and stable discharge can be realized. In addition, from the viewpoint of causing a liquid pool formed by mist generated during continuous ejection to flow from the top plate to the nozzle substrate as a thin film, among the surfaces located on the side of the top plate where the ink is ejected, the nozzle More preferably, the region adjacent to the substrate is used as a parent ink region as a part of the top plate.
The inventor considers the reason why the above-described ejection stabilization can be realized as follows.
Even if mist generated by continuously ejecting ink at a high frequency adheres to the nozzle surface, the parent ink treatment, that is, the entire surface of the nozzle substrate with a receding contact angle of 60 ° or less and a part of the top plate are treated as the parent ink region. Thus, a thin film is formed without the above-described mist getting wet and spreading to form a large liquid pool. In particular, the large liquid pool formed by the growth of mist attached to the top plate does not destabilize the amount of ink returning to the nozzle when it reaches the nozzle substrate, making it a thin film compared to the large liquid pool. Since the ink gradually flows into the nozzle little by little, it is considered that the ejection can be stabilized without blocking the nozzle. It is more preferable to set the receding contact angle of the parent ink region to 30 ° or less from the viewpoint of forming a thinner film and allowing the ink to flow into the nozzles little by little to stabilize the ejection.

The ink contains a color material. The coloring material can be a dye or a pigment, but is preferably a pigment because it has good dispersibility with respect to the components of the ink and is excellent in weather resistance. Although a pigment is not specifically limited, For example, the organic pigment or inorganic pigment of the following number described in a color index can be used.
As the pigment, for example, inorganic pigments or organic pigments such as carbon black, titanium oxide, and calcium carbonate can be used. Examples of the organic pigment include insoluble azo pigments such as toluidine red, toluidine maroon, Hansa yellow, benzidine yellow, and pyrazolone red, soluble azo pigments such as lithol red, heliobordeaux, pigment scarlet, and permanent red 2B; alizarin, indanthrone, Derivatives from vat dyes such as thioindigo maroon; Phthalocyanine organic pigments such as phthalocyanine blue and phthalocyanine green; Quinacridone organic pigments such as quinacridone red and quinacridone magenta; Perylene organic pigments such as perylene red and perylene scarlet; Isoindolinone-based organic pigments such as linone yellow and isoindolinone orange; Pyranthrone-based organic pigments such as pyranthrone red and pyranthrone orange; Organic organic pigments, condensed azo organic pigments, benzimidazolone organic pigments, quinophthalone organic pigments such as quinophthalone yellow; isoindoline organic pigments such as isoindoline yellow; other pigments such as flavanthron yellow and acylamide yellow Nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet and the like.

  Organic pigments are exemplified below by color index (CI) numbers.

C. I. Pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 109, 110, 117, 120, 125, 128, 129, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185,
C. I. Pigment Orange 16, 36, 43, 51, 55, 59, 61,
C. I. Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 177, 180, 192, 202, 206, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240,
C. I. Pigment violet 19, 23, 29, 30, 37, 40, 50,
C. I. Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64,
C. I. Pigment Green 7, 36,
C. I. Pigment brown 23, 25, 26,

  Among the above pigments, quinacridone-based, phthalocyanine-based, benzimidazolone-based, isoindolinone-based, condensed azo-based, quinophthalone-based, and isoindoline-based organic pigments are preferable because of their excellent light resistance.

  The organic pigment preferably has an average particle size in the ink of 10 nm or more and 150 nm or less as measured by laser scattering. When the average particle size of the pigment is less than 10 nm, a decrease in light resistance may occur due to a decrease in the particle size. When the thickness exceeds 150 nm, a minute mist called a satellite is likely to be generated, and due to the mist adhering, a liquid puddle is generated, and discharge failure due to the liquid puddle is likely to occur. In the present invention, the ink described above can also be used preferably. For example, when titanium oxide is contained in the ink, in order to provide whiteness and concealability, the image formation is performed with an average particle size of 150 nm to 300 nm, preferably 180 nm to 250 nm, and therefore the present invention is preferably used. Can do.

  Further, it is preferable to remove coarse particles by sufficiently dispersing or filtering so that the maximum particle diameter of the pigment in the inkjet ink does not exceed 3.0 μm.

Example 1
With reference to FIG.4 and FIG.5, the inkjet head 100A of Example 1 as an Example of the inkjet head 100 of this Embodiment is demonstrated. FIG. 4 is a cross-sectional view of the inkjet head 100A.

  As shown in FIG. 4, the ink jet head 100A includes a nozzle substrate 11A and a top plate 3A. FIG. 4 is a cross-sectional view of the XY plane passing through the nozzle 11a of the nozzle substrate 11A.

In the present embodiment, the ink-jetting direction side surface of the nozzle substrate 11A and the entire top plate have the parent ink regions 1cA and 3cA, and the nozzle substrate 11A slightly protrudes from the top plate 3A in the X direction. By performing dry etching on the surfaces of the nozzle substrate 11A and the top plate 3A on the ink ejection direction side (+ X side) as a vacuum plasma treatment as indicated by a plurality of arrows in FIG. 4, the parent ink region 1cA is obtained. , 3cA is formed.
In this embodiment, dry etching is performed. However, the present invention is not limited to this, and various methods capable of performing ink-philic treatment (with a receding contact angle of 60 ° or less) can be used.
Here, the front surface is a surface viewed from the + X side, and the front surface is the front surface at the position where the value of the X axis is the highest, and the same applies to the following description.

Here, a manufacturing method of the ink jet head 100A will be described. FIG. 5 is a diagram illustrating a manufacturing flow of the manufacturing method according to the first embodiment. In the following embodiments, the configuration including the top plate is described, but it goes without saying that the configuration excluding the top plate may be used.
As shown in FIG. 5, Example 1 includes an ink repellent layer application step F1, a protective layer application step F2, a nozzle formation step F3, an assembly step F4, a protective layer peeling step F5, and a parent ink step F6. Hereinafter, each process is explained in full detail.
The ink repellent layer application step F1 is a step in which an ink repellent layer is first formed on the surfaces of the nozzle substrate 11A and the top plate 3A before assembling each member of the inkjet head 100A. The ink repellent layer preferably contains a heat-meltable fluororesin. The ink repellent layer containing a fluororesin has excellent ink repellency with respect to a wide range of ink types, and is difficult to permeate ink and has excellent durability.

  Application of the ink repellent layer can improve the durability of the ink repellent layer by applying a coating liquid containing a fluororesin, drying, and then heat treating to melt the fluororesin. The coating liquid for the ink repellent layer contains a solvent such as water in addition to the fluororesin, and may contain a surfactant or the like.

  Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer. (ETFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), and the like can be used, but FEP has a low critical surface tension, excellent ink repellency, and a heat treatment temperature of 300. C. to 400.degree. C. is preferable because the melt viscosity is low and a uniform film can be formed. When polyoxyethylene alkyl ether is used as the surfactant, it is possible to further improve the durability of the ink repellent layer.

  As an application method for forming the ink repellent layer, spray coating, spin coating, brush coating, dip coating, wire bar coating, or the like can be used. In the first embodiment, spray coating is preferable because the front and side surfaces of the top plate 3A can be applied in a single application step, and efficient application is possible.

  As a method of providing the ink repellent layer on a part of the back surface of the top plate 3A, after masking the non-coated surface of the back surface, the method of coating the back surface, and before the fluidity of the coating liquid applied to the side surface is lost Although the method by which the side surface coating liquid wets a part of the back surface by heating is exemplified, the latter is preferable from the viewpoint of the efficiency of the coating process.

  When the width at which the ink repellent layer spreads from the end of the back surface of the top plate 3A is made narrower than the width of the bonding surface between the housing 2 and the top plate 3A, the housing 2 and the top plate 3A are separated by the adhesive layer 4. It is preferable that the area directly bonded without using the ink repellent layer is increased, and the adhesive force between the housing 2 and the top plate 3 is increased. After coating and drying, the coating layer is heat treated. The treatment temperature is preferably equal to or higher than the melting point of the ink repellent layer, and particularly preferably from 300 ° C to 400 ° C.

Next, the protective layer applying step F2 will be described in detail.
This is a step of laminating a protective layer on the ink repellent layer applied to the nozzle substrate 11A by the ink repellent layer applying step F1. For example, it can be formed by cutting a nozzle substrate on which a film is pasted to a desired size after the roll-like film is peeled off from the release material and pasted on the nozzle substrate. The protective layer can be peeled off from the nozzle substrate 11A in a protective layer peeling step F5, which will be described in detail later, and the shape of the front surface side of the nozzle 11a of the nozzle substrate 11A becomes an irregular and inappropriate shape in the subsequent nozzle forming step F3. Although it will not specifically limit if it does not become, For example, a polyethylene terephthalate resin, a polypropylene resin, a polyethylene resin, a vinyl chloride resin, an acrylic resin, a polyimide resin etc. can be used as a protective film. Moreover, although the protective film mentioned above may be used independently as a base material, you may use the adhesive tape and masking tape which apply | coated the acrylic adhesive, the rubber adhesive, etc. to the base material as an adhesive, for example. In addition, it is preferable to use polyester as a base material and to use a rubber-type adhesive as an adhesion layer.

Next, the nozzle forming step F3 will be described in detail below.
The nozzle forming step F3 is a step of forming the nozzle 11a by irradiating a laser beam from the rear surface to the nozzle substrate 11A to which the protective film applied to the front surface by the protective layer applying step F2 is attached. At this time, the protective layer (protective film) is for preventing the shape of the front surface side of the nozzle 11a of the nozzle substrate 11A from becoming an irregular and inappropriate shape during laser light irradiation.

Next, the assembly process F4 will be described in detail.
The assembly process F4 is a process of attaching at least the top plate 3A to the nozzle substrate 11A.
Although the order is not particularly limited, since the nozzle substrate 11A is very thin, it is preferable to first join the head chip and the nozzle substrate 11A. Positioning holes are respectively formed in the nozzle substrate 11A and the head chip, and the nozzle holes 11A and the head chip are joined so that the positioning holes provided are aligned. Positioning holes are provided in each of the nozzle substrate 11A and the top plate 3A to which the head chip is bonded in order to position and join the nozzle substrate 11A and the top plate 3A. When the nozzle substrate 11 </ b> A and the top plate 3 </ b> A are joined, they are positioned and joined so that the positioning holes provided respectively coincide. Further, when the nozzle substrate 11A and the top plate 3A are bonded, there is no particular limitation as long as they can be bonded, but for example, bonding is performed via an adhesive containing resin. As described above, the configuration in which the positioning hole is provided in each is described. For example, the positioning hole is formed on one side, the alignment mark is formed on the other side, and positioning is performed so that the alignment mark can be seen from the positioning hole. It is good also as composition which performs. Further, the positioning holes of the nozzle substrate 11A may be the same as those used when the head chip is bonded and those used when the top plate 3A is bonded.
In addition, this process should just include the process of attaching the top plate 3A to the nozzle substrate 11A at least, and may include the process of joining the housing | casing 2 grade | etc.,. For example, the top plate 3A and the housing 2 may be assembled at the same time.

Next, the protective layer peeling step F5 will be described in detail.
The protective layer peeling step F5 is a step of exposing the front surface of the nozzle substrate covered with the protective layer in order to perform the ink-philic process described later. For example, the edge of the protective layer is grasped with tweezers and peeled off. Further, when the adhesive force between the protective layer and the nozzle substrate is strong, the adhesive tape may be attached to the upper surface of the protective layer and peeled off by pulling up the adhesive tape.
In this embodiment, the protective layer peeling step F5 is performed after the assembly step F4. However, it may be performed before the assembly step F4. That is, the protective layer (protective film) is not particularly limited as long as it is peeled off before the ink-philic process F6. The nozzle substrate 11A is flowed in a process with a protective layer (protective film) applied just before the parent ink process F6 (hereinafter, the process from the step of forming an ink repellent layer on the nozzle substrate to the parent ink process is referred to as process flow. 11), the nozzle substrate 11A can be protected by the protective film. Further, after the nozzle 11a is formed, for example, in the assembling step F4, since the protective film has a hole, there is a possibility that foreign substances such as adhesive and dust may enter from the hole. Therefore, after the nozzle forming step F3, the protective layer peeling step F5 may be performed, and the protective layer applying step may be performed again to newly apply a protective film without holes to the nozzle substrate 11A.
In addition, since the ink repellent layer is formed in advance by the ink repellent layer applying step F1 before the protective layer applying step F2, it is possible to prevent a part of the protective layer from remaining on the nozzle substrate 11A when the protective layer is peeled off. . For example, when a protective film is used as the protective layer and the protective layer is applied by bonding the protective layer and the nozzle substrate 11A through an adhesive layer, the adhesive residue generated when the protective film of the nozzle substrate 11A is peeled off can be reduced. . By reducing the adhesive residue of the protective film of the nozzle substrate 11A, it is preferable from the viewpoint of improving the landing accuracy (straightness) of the droplets after manufacture and reducing the ejection angle distribution defect.

Next, the parent ink process F6 will be described in detail below.
The ink-repellent layers on the front surfaces of the nozzle substrate 11A and the top plate 3A are formed with the parent ink regions 1cA and 3cA by using dry etching as the vacuum plasma treatment. The receding contact angles of the parent ink regions 1cA and 3cA are set to 60 ° or less. In the present embodiment, the top plate 3A is also subjected to the parent ink processing, but the present invention is not limited to this. For example, in this step, it is needless to say that the top plate 3A may be provided with an ink repellent layer without performing the ink affinity treatment.
At the time of dry etching, it is preferable to perform dry etching by attaching a metal protective material covering the main body including the casing 2 of the ink jet head 100A, the electrical system, and the like to the ink jet head 100A. The completed inkjet head 100A is inspected using an inspection liquid or the like. The ink jet head 100A may be dried up by drying the test liquid, although the test liquid used in the test may remain in the actuator 1 and the nozzle 11a flow path and the entire nozzle hole of the nozzle substrate 11A. In addition, although the dried-up inkjet head 100A can be mounted and used in the inkjet recording apparatus 1000, from the viewpoint of further improving the discharge stability, before mounting on the inkjet recording apparatus 1000 and performing a recording operation, It is preferable to wet the flow path and nozzle surface of the ink jet head 100A with the ink to be used. Further, the ink to be wet as described above is not limited to the ink to be used, and for example, a dummy ink excluding a pigment or a dye may be used.
In addition, although the example which performs an ink-philic process by dry etching was described, it is not limited to dry etching, For example, you may use wet etching. According to wet etching, the risk of damage to the electrical system of the inkjet head 100A can be reduced.

(Example 2)
With reference to FIG. 6, the inkjet head 100B of Example 2 as an example of the inkjet head 100 of this Embodiment is demonstrated. FIG. 6 is a cross-sectional view of the inkjet head 100B. In addition, the same code | symbol is attached | subjected to the same member as Example 1, and the description is abbreviate | omitted.

  As shown in FIG. 6, the inkjet head 100B includes a nozzle substrate 11A and a top plate 3B. FIG. 6 is a cross-sectional view of the XY plane passing through the nozzle 11a of the nozzle substrate 11A.

  The ink jet head 100B has the parent ink regions 1cA and 3cB in which the ink repellent layer is subjected to the parent ink treatment on the entire surface of the ink ejection side of the nozzle substrate 11A and the entire top plate 3B as in the first embodiment. In the second embodiment, the top plate 3B is a recess which is a recess structure having a concave structure in which the height in the X direction changes in two steps as it moves away from the nozzle substrate 11A in the Y direction and Z direction (direction perpendicular to the XY plane). 3B1. The height of the recess 3B1 in the X direction is half the height of the forefront of the top plate 3B. Further, the recess 3B1 is formed in a region having a length that is ½ of the length of the top plate 3B on the nozzle substrate 11A side in the Y direction. Further, the recess 3B1 is formed in a region having a length that is ½ of the length of the top plate 3B on the nozzle substrate 11A side in the Z direction. The recess 3B1 is formed in a band shape around the nozzle substrate 11A when viewed from the + X direction. The front surface of the recess 3B1 is lower in the X direction than the front surface of the nozzle substrate 11A. The top surface of the top plate 3B (the front surface of the convex portion) is higher in the X direction than the front surface of the nozzle substrate 11A. The position and shape of the recess 3B1 are merely examples, and the present invention is not limited to this example. For example, the top surface of the top plate 3B may be configured to have the same height in the X direction as the front surface of the nozzle substrate 11A. Further, the height of the front surface of the recess 3B1 in the X direction may be equal to or higher than the height of the front surface of the nozzle substrate 11A. The manufacturing method of the inkjet head 100B is the same as the manufacturing method of the inkjet head 100A of the first embodiment.

Example 3
With reference to FIG. 7, an inkjet head 100C of Example 3 as an example of the inkjet head 100 of the present embodiment will be described. FIG. 7 is a cross-sectional view of the inkjet head 100C. In addition, the same code | symbol is attached | subjected to the same member as Example 1, and the description is abbreviate | omitted.

  As shown in FIG. 7, the ink jet head 100C includes a nozzle substrate 11A and a top plate 3C. FIG. 7 is a cross-sectional view of the XY plane passing through the nozzle 11a of the nozzle substrate 11A.

  The top plate 3C has the same shape as the top plate 3A of the first embodiment. However, the entire front surface is not treated with ink, and a part of the front surface of the top plate 3C, more specifically, the top plate 3C. A region adjacent to the nozzle substrate 11A in the front surface of the plate 3C is referred to as a parent ink region 3cC. In the present embodiment, the parent ink region 3cC is formed in a region having a length of 1/3 on the nozzle substrate 11A side in the length of the top plate 3C in the Y direction. Further, the parent ink region 3cC is formed in a region of 1/3 of the length of the top plate 3C on the nozzle substrate 11A side in the Z direction. The position and shape of the parent ink region 3cC are merely examples, and are not limited to this example.

  The manufacturing method of the inkjet head 100C is the same as the manufacturing method of the inkjet head 100A of Example 1 up to the protective layer peeling step F5 of the inkjet head 100C. In the parent ink step F6, the inkjet head 100C after the assembly step F4 or the protective layer peeling step F5 has a rectangular shape that exposes the entire front surface of the nozzle substrate 11A and a part of the front surface of the top plate 3C adjacent to the nozzle substrate 11A. A protective material 21 such as a metal having a hole is provided on the top plate 3C, and the ink repellent layer on the front surface of the nozzle substrate 11A and the top plate 3C is subjected to ink affinity treatment by performing dry etching as a vacuum plasma treatment. The parent ink areas 1cA and 3cC are formed. The parent ink region 3cC is formed in a band shape around the nozzle substrate 11A when viewed from the + X side. The protective material 21 is removed. An ink repellent area 3aC as an ink repellent layer is left on the top plate 3C.

(Example 4)
With reference to FIG. 8, the inkjet head 100D of Example 4 as an example of the inkjet head 100 of this Embodiment is demonstrated. FIG. 8 is a cross-sectional view of the inkjet head 100D. In addition, the same code | symbol is attached | subjected to the same member as Example 1, and the description is abbreviate | omitted.

  As shown in FIG. 8, the ink jet head 100D includes a nozzle substrate 11A and a top plate 3D. FIG. 8 is a cross-sectional view of the XY plane passing through the nozzle 11a of the nozzle substrate 11A.

  The top plate 3D has a recess 3D1 having the same position and shape as the recess 3B1 of the second embodiment. However, the top plate 3D is not subjected to the parent ink treatment on the entire front surface, but only a part thereof is subjected to the parent ink treatment, and the parent ink region 3cD is formed on a part of the front surface of the recess 3D1 of the top plate 3D. Yes. Further, the parent ink region 3cD is formed in a region having a length of 1/3 on the nozzle substrate 11A side in the length of the recess 3D1 in the Y direction. Further, the parent ink region 3cD is formed in a region having a length of 1/3 on the nozzle substrate 11A side in the length of the recess 3D1 in the Z direction. The positions and shapes of the concave portion 3D1 and the parent ink region 3cD are merely examples, and are not limited to this example.

  The manufacturing method of the inkjet head 100D is the same as the manufacturing method of the inkjet head 100A of Example 1 up to the protective layer peeling step F5 of the inkjet head 100D. In the parent ink process F6, the protective material 21 is provided on the top plate 3D in the inkjet head 100D after the assembly process F4 or the protective layer peeling process F5, and the nozzle substrate 11A is obtained by performing dry etching as a vacuum plasma treatment. The ink repellent layer on the front surface of the top plate 3D is subjected to the ink-philic process, and the ink-parent regions 1cA and 3cD are formed. The parent ink region 3cD is formed in a band shape around the nozzle substrate 11A when viewed from the + X side. The protective material 21 is removed. An ink repellent area 3aD as an ink repellent layer is left on the top plate 3D.

(Example 5)
With reference to FIG. 9, an inkjet head 100E of Example 5 as an example of the inkjet head 100 of the present embodiment will be described. FIG. 9 is a cross-sectional view of the inkjet head 100E. In addition, the same code | symbol is attached | subjected to the same member as Example 1, and the description is abbreviate | omitted.

  As shown in FIG. 9, the ink jet head 100E includes a nozzle substrate 11A and a top plate 3E. FIG. 9 is a cross-sectional view of the XY plane passing through the nozzle 11a of the nozzle substrate 11A.

  The top plate 3E has a tapered portion 3E1 which is a tapered recess structure different from the top plate 3B of the second embodiment. In the present embodiment, since the nozzle substrate 11A is disposed at a higher position in the X direction than the lowest portion of the front surface of the tapered portion 3E1, the lowest portion of the front surface of the tapered portion 3E1 and the side wall of the actuator 1 are disposed. Is touching. The taper portion 3E1 is gently extended from the outermost front surface (the frontmost portion on the opposite side to the nozzle substrate 11A in the taper portion 3E1) to the side wall of the opening b in which the nozzle substrate 11A is located (the side wall of the actuator 1 and the nozzle substrate 11A). It is continuous. In addition, although the taper part 3E1 shall be in contact with the side wall of the actuator 1, it is not limited to this, The taper part 3E1 is good also as what is in contact with the side wall of the nozzle substrate 11A. In addition, providing the parent ink region also on the side wall of the nozzle substrate 11A or the actuator 1 is more preferable from the viewpoint of facilitating the adhering ink to flow into the nozzle substrate 11A. The tapered portion 3E1 is formed in a band shape around the nozzle substrate 11A when viewed from the front. The lowest portion of the front surface of the tapered portion 3E1 has a lower height in the X direction than the front surface of the nozzle substrate 11A. The front surface of the high portion of the top plate 3E (the plane in contact with the highest portion of the front surface of the tapered portion 3E1) is higher in the X direction than the front surface of the nozzle substrate 11A. In the top plate 3E, the entire front surface is not subjected to the ink-philic treatment, and only a part of the front surface is subjected to the ink-philic treatment, and more specifically, a part of the front surface of the tapered portion 3E1 of the top plate 3E. Of the 3E tapered portion 3E1, a parent ink region 3cE that has been subjected to a parent ink process is formed in a region adjacent to the nozzle substrate 11A. The tapered portion 3E1 is formed in a region having a length that is ½ of the length of the top plate 3E on the nozzle substrate 11A side in the Y direction. Further, the taper portion 3E1 is formed in a region having a length of ½ of the length of the top plate 3E on the nozzle substrate 11A side in the Z direction. The parent ink region 3cE is formed in a region of ½ length on the nozzle substrate 11A side in the length of the tapered portion 3E1 in the Y direction. Further, the parent ink region 3cE is formed in a region having a half length on the nozzle substrate 11A side in the length of the tapered portion 3E1 in the Z direction. The positions and shapes of the tapered portion 3E1 and the parent ink region 3cE are merely examples, and are not limited to this example. For example, the height in the X direction of the lowest portion of the front surface of the tapered portion 3E1 is set to be equal to or higher than the height of the front surface of the nozzle substrate 11A, and adheres to the front surface of the nozzle substrate 11A without passing through the nozzle substrate 11A or the side wall of the actuator 1. It is good also as a structure in which the mist which flowed is directly flowed in.

  The manufacturing method of the inkjet head 100E is the same as the manufacturing method of the inkjet head 100A of Example 1 until the protective layer peeling process F5 of the inkjet head 100E. In the parent ink process F6, the inkjet head 100E after the assembly process F4 or the protective layer peeling process F5 is provided with a protective material 21 having a rectangular hole on the top plate 3E, and dry etching is performed as a vacuum plasma treatment. Thus, the ink repellent layer on the front surface of the nozzle substrate 11A and the top plate 3E is subjected to the ink affinity process, and the ink affinity regions 1cA and 3cE are formed. The parent ink region 3cE is formed in a band shape around the nozzle substrate 11A when viewed from the + X side. The protective material 21 is removed. An ink repellent area 3aE as an ink repellent layer is left on the top plate 3E.

(Example 6)
With reference to FIG. 10, an inkjet head 100F of Example 6 as an example of the inkjet head 100 of the present embodiment will be described. FIG. 10 is a cross-sectional view of the inkjet head 100F. In addition, the same code | symbol is attached | subjected to the same member as Example 1, and the description is abbreviate | omitted.

  As shown in FIG. 10, the inkjet head 100F includes a nozzle substrate 11A and a top plate 3F. FIG. 10 is a cross-sectional view of the XY plane passing through the nozzle 11a of the nozzle substrate 11A.

  The top plate 3F has a tapered portion 3F1 having the same position and shape as the tapered portion 3E1 of the fifth embodiment. The top surface of the top plate 3F has not been subjected to the parent ink treatment on the entire front surface, only the entire front surface of the tapered portion 3F1 has been subjected to the parent ink treatment, and the entire front surface of the tapered portion 3F1 of the top plate 3F has been subjected to the parent ink processing. A parent ink region 3cF is formed. The positions and shapes of the tapered portion 3F1 and the parent ink region 3cF are merely examples, and are not limited to this example.

  The manufacturing method of the inkjet head 100F is the same as the manufacturing method of the inkjet head 100A of Example 1 up to the protective layer peeling step F5 of the inkjet head 100F. In the parent ink process F6, the inkjet head 100F after the assembly process F4 or the protective layer peeling process F5 is provided with a protective material 22 having a rectangular hole larger than the protective material 21 on the top plate 3F, and is subjected to vacuum plasma treatment. As a result, by dry etching, the ink repellent layer on the entire front surface of the nozzle substrate 11A and the ink repellent layer on the front surface of the top plate 3F are converted into the parent ink, and the parent ink regions 1cA and 3cF are formed. The parent ink region 3cF is formed in a band shape around the nozzle substrate 11A when viewed from the + X side. The protective material 22 is removed. An ink repellent area 3aF as an ink repellent layer is left on the top plate 3F.

(Example 7)
With reference to FIG. 11, an inkjet head 100G of Example 7 as an example of the inkjet head 100 of the present embodiment will be described. FIG. 11A to FIG. 11D are cross-sectional views of respective steps of the ink-philic process of the inkjet head 100F. In addition, the same code | symbol is attached | subjected to the same member as Example 1, and the description is abbreviate | omitted.

  As shown in FIG. 11A, the ink jet head 100G includes a nozzle substrate 11A and a top plate 3G. 11A to 11D are cross-sectional views of the XY plane passing through the nozzle 11a of the nozzle substrate 11A.

  The top plate 3G has a tapered portion 3G1 having the same position and shape as the tapered portion 3E1 of the fifth embodiment. In addition, the position and shape of this taper part 3G1 are examples, Comprising: It is not limited to this example.

  The manufacturing method of the inkjet head 100G is the same as the manufacturing method of the inkjet head 100A of Example 1 up to the protective layer peeling step F5 of the inkjet head 100G. In the parent ink process F6, as shown in FIG. 11A, the inkjet head 100G after the assembly process F4 or the protective layer peeling process F5 is provided with a protective material 31 having a rectangular hole on the top plate 3G. As the vacuum plasma treatment, by performing dry etching for a predetermined time, the ink repellent layer on the entire front surface of the nozzle substrate 11A is subjected to the parent ink treatment, and has the parent ink region 1cA. The protective material 31 is removed.

  Next, as shown in FIG. 11 (b), the inkjet head 100G is provided with a protective material 32 having a rectangular hole larger than the protective material 31 on the top plate 3G. By performing dry etching, the entire surface of the parent ink region 1cA and a part of the ink repellent layer on the front surface of the top plate 3G are subjected to the parent ink treatment, and the parent ink region 1cA that has been changed to the parent ink is subjected to the parent ink treatment. A parent ink region 3cG is formed. The parent ink area 3cG includes a parent ink area 3cG1. The parent ink region 3cG1 is formed in a region of ½ length on the nozzle substrate 11A side in the length of the tapered portion 3G1 in the Y direction. In addition, the parent ink region 3cG1 is formed in a region having a length that is ½ of the length of the tapered portion 3G1 on the nozzle substrate 11A side in the Z direction. The protective material 32 is removed.

  Next, as shown in FIG. 11 (c), the inkjet head 100G is provided with a protective material 33 having a rectangular hole larger than the protective material 32 on the top plate 3G. By performing dry etching, the entire surface of the parent ink region 1cA, the entire surface of the parent ink region 3cG1, and a part of the ink repellent layer on the front surface of the top plate 3G are subjected to the parent ink treatment, and the parent ink that has been changed to the parent ink. Regions 1cA and 3cG1 and a parent ink region 3cG2 are formed. The parent ink region 3cG includes parent ink regions 3cG1 and 3cG2. The parent ink region 3cG2 is formed in a region having a length that is ½ of the length of the tapered portion 3G1 on the side opposite to the nozzle substrate 11A in the Y direction. Further, the parent ink region 3cG2 is formed in a region having a half length on the opposite side to the nozzle substrate 11A in the length of the tapered portion 3G1 in the Z direction. The protective material 33 is removed.

  Next, as shown in FIG. 11 (d), the inkjet head 100G is provided with a protective material 34 having a rectangular hole larger than the protective material 33 on the top plate 3G. By performing dry etching, the entire surface of the parent ink region 1cA, the entire surface of the parent ink regions 3cG1 and 3cG2, and a part of the ink repellent layer on the front surface of the top plate 3G are subjected to the parent ink treatment, and the parent ink that has been changed to the parent ink region. Ink regions 1cA, 3cG1, 3cG2 and a parent ink region 3cG3 are formed. The parent ink region 3cG includes parent ink regions 3cG1, 3cG2, and 3cG3. The parent ink region 3cG3 is formed in a region having the same length as the parent ink region 3cG1 on the tapered portion 3G1 side in the length of the surface of the top plate 3G in the Y direction. Further, the parent ink region 3cG3 is formed in a region having the same length as the parent ink region 3cG1 on the tapered portion 3G1 side in the length of the surface of the top plate 3G in the Z direction. In this way, a part of the front surface of the top plate 3G and the entire front surface of the tapered portion 3G1 are subjected to ink-philic processing. The parent ink region 3cG is formed in a band shape around the nozzle substrate 11A when viewed from the + X side. The top plate 3G has a four-step gradation structure of the parent ink processing in which the degree of ink affinity becomes lower (the receding contact angle becomes larger) as it moves away from the nozzle substrate 11A in the Y direction and the Z direction. That is, in the inkjet head 100G, the top plate 3G is changed so that the receding contact angle of the ink becomes smaller from the outermost surface of the front surface to the side wall of the opening b where the nozzle substrate 11A is located inside. The protective material 34 is removed. An ink repellent area 3aG as an ink repellent layer is left on the top 3G.

  The positions and shapes of the parent ink regions 3cG, 3cG1, 3cG2, and 3cG3 are merely examples, and the present invention is not limited to this example. Further, the number of stages of parent ink processing in the parent ink areas 1cA and 3cG is not limited to four.

(Example 8)
With reference to FIG. 12, the inkjet head 100J of Example 8 as an example of the inkjet head 100 of this Embodiment is demonstrated. FIG. 12 is a cross-sectional view of the inkjet head 100J. In addition, the same code | symbol is attached | subjected to the same member as Example 1, and the description is abbreviate | omitted.

  As shown in FIG. 12, the inkjet head 100J includes a nozzle substrate 11A and a top plate 3J. The inkjet head 100J has a parent ink region 1cA only on the entire front surface of the nozzle substrate 11A.

  The manufacturing method of the inkjet head 100J is the same as the manufacturing method of the inkjet head 100C of the third embodiment. However, the protective material 23 is used in place of the protective material 21 in the parent ink process F6. The protective material 23 has a rectangular hole that exposes only the entire front surface of the nozzle substrate 11A. In the inkjet head 100J after the assembly process F4 or the protective layer peeling process F5, the protective material 23 is provided on the top plate 3J, and dry etching is performed as a vacuum plasma treatment, whereby the ink repellent layer on the front surface of the nozzle substrate 11A is formed. The parent ink process is performed to form a parent ink area 1cA. The protective material 23 is removed. An ink repellent area 3aJ as an ink repellent layer is left on the entire front surface of the top plate 3J.

Example 9
With reference to FIG. 13, an ink jet head of Example 9 as an example of the ink jet head 100 of the present embodiment will be described. FIG. 13 is a cross-sectional view of the inkjet head 100K. In addition, the same code | symbol is attached | subjected to the same member as Example 1, and the description is abbreviate | omitted.

  As shown in FIG. 13, the inkjet head 100K includes a nozzle substrate 11A and a top plate 3K. The ink jet head 100K has a parent ink region 1cA only on the entire front surface of the nozzle substrate 11A.

  The manufacturing method of the inkjet head 100K is the same as the manufacturing method of the inkjet head 100D of the fourth embodiment. However, the protective material 23 is used in place of the protective material 21 in the parent ink process F6. In the inkjet head 100K after the assembly process F4 or the protective layer peeling process F5, the protective material 23 is provided on the top plate 3K, and dry etching is performed as a vacuum plasma treatment, whereby the ink repellent layer on the front surface of the nozzle substrate 11A is formed. The parent ink process is performed to form a parent ink area 1cA. The protective material 23 is removed. An ink repellent area 3aJ as an ink repellent layer is left on the entire front surface of the top plate 3J.

  Here, with reference to FIG. 14, evaluation of Examples 1-9 and Comparative Examples 1-3 is demonstrated. FIG. 14 is a cross-sectional view of the inkjet head 100H of Comparative Example 3.

The configurations and evaluations of the inkjet heads of Examples 1 to 9 and Comparative Examples 1 to 3 are summarized in Table 1 below.

  The ink jet head of Comparative Example 1 has the same configuration as that of the ink jet head 100A of Example 1, but an ink repellent layer is not formed on the nozzle substrate (and the top plate) during the process flow, and the nozzle substrate and the top plate have a parent structure. Ink treatment is not performed.

  The inkjet head of Comparative Example 2 has the same configuration as the inkjet head 100A of Example 1, but an ink repellent layer is formed on the nozzle substrate (and the top plate) during the process flow. No parent ink treatment has been performed.

  The inkjet head 100H of Comparative Example 3 has the same configuration as that of the inkjet head 100A of Example 1, but the parent ink process is performed only in the vicinity of the nozzle holes of the nozzle substrate, and the top plate is subjected to the parent ink process. Absent.

  As shown in FIG. 14, the inkjet head 100H of Comparative Example 3 includes a nozzle substrate 11H and a top plate 3H. The nozzle substrate 11H has the same shape as the nozzle substrate 11A of the first embodiment, and has a parent ink region 1cH that has been subjected to parent ink processing in a region near the nozzle hole of the nozzle 11a. The top plate 3H has the same shape as the top plate 3A of the first embodiment. However, when the inkjet head 100H is manufactured, the protective material 41 is provided on the nozzle substrate 11H and the top plate 3H after the assembly of the inkjet head 100H.

  The protective material 41 is a metal mask having a hole portion with a diameter of 100 μm at the position of the nozzle holes on the front surface of all the nozzles 11a. After the protective material 41 is aligned so that the hole portion is at the center of the nozzle hole of each nozzle 11a, the protective material 41 is fixed in contact with the nozzle substrate 11H. Then, dry etching is performed on the ink repellent layer of the nozzle substrate 11A as a vacuum plasma treatment from the front surface in the X direction. The protective material 41 is removed. In this manner, in the ink jet head 100H, the ink repellent layer is subjected to ink affinity treatment only in the area near the nozzle hole of the nozzle 11a on the ink discharge side surface of the nozzle substrate 11H.

  The ejection angle distribution in the evaluation of Table 1 is an evaluation of the ink ejection distribution angle after completion of the inkjet head. In this evaluation, the inkjet heads of Examples 1 to 9 and Comparative Examples 1 to 3 having 512 nozzle holes capable of discharging droplets having an average discharge droplet amount of 14 [pL] were prepared and used. An ink made of n-tetradecane containing no pigment was used, and it was attached to a drawing apparatus. The ink was ejected by sending a pulse signal from a drive circuit to the head, and the paper was transported once to draw a nozzle test pattern. The landing deviation of the dots printed for all the nozzles was measured, and the ejection angle was calculated as a parameter indicating the straightness of the droplet.

In the evaluation of the injection angle distribution in Table 1,
○: All discharge nozzles fall within the range of −1 ° to + 1 °.
X: All discharge nozzles do not fall within the range of -1 ° to + 1 °.
It was.

  In the evaluation of the ejection angle distribution in Table 1, the ink jet heads of Comparative Examples 1 and 3 were all evaluated as x, which was not good. The ink jet heads of Comparative Example 2 and Examples 1 to 9 were all good and good evaluation was obtained.

  The continuous ejection stability in the evaluation of Table 1 is an evaluation by confirming the presence or absence of ejection abnormality (ink missing, bending, speed reduction) after 30 minutes of continuous ejection. In the evaluation of continuous injection stability, the effect of the discharge stability began to appear when the discharge frequency was 5 [kHz] or higher, and became noticeable when the frequency was 10 [kHz] or higher. Regarding the ejection stability, the amount of one ejected droplet is appropriately 42 [pL] or less, preferably 30 [pL] or less, and 15 [pL] or less, and a higher effect was confirmed.

  In addition, as the ink used in the evaluation of the continuous ejection stability, an ink containing particles that are susceptible to mist is used. The region of the particle diameter of the ink used in the inkjet head is about 1 [nm] to 10 [μm] in terms of average particle diameter. In the inkjet of the present embodiment, a preferable particle diameter range is 10 [nm] to 3 [μm], and 50 [nm] to 600 [nm] is more preferable. This range includes ordinary organic pigment inks and ordinary inorganic pigment inks.

The density of the ink, can be preferably used 0.75~2.2 [g / cm ^3], a more preferred density is 0.75~1.8 [g / cm ^3]. This range includes ordinary organic pigment ink, ordinary inorganic pigment ink, and silver ink.

In the evaluation of continuous ejection stability in Table 1, inkjet heads of Examples 1 to 9 and Comparative Examples 1 to 3 having 512 nozzle holes capable of ejecting droplets having an average droplet volume of 14 [pL] were produced. Used. As the organic solvent for the ink used, n-tetradecane was used, and an ink containing 5 wt% of a pigment having an average particle size of 250 nm was used.
A continuous discharge printing test was performed by transporting paper at a transport speed of 24 [m / min] while emitting the ink described above at a discharge frequency of 10 [kHz] by sending a pulse signal from the drive circuit to the inkjet head. At this time, continuous discharge printing was stopped after 30 minutes, and a nozzle test pattern was drawn once. With respect to all nozzles, the presence or absence of landed dods and the injection angle were measured.

In the evaluation of continuous injection stability in Table 1,
A: There are no nozzles in which no landing dots are observed, and all the discharge nozzles fall within the range of -1 ° to + 1 °.
○: There are no nozzles where no landing dot was observed, but all the discharge nozzles do not fall within the range of -1 ° to + 1 °.
Δ: 1 to 20 nozzles in which no landing dots were observed,
X: There are 20 or more nozzles where no landing dots were observed,
It was.

  In the evaluation of the continuous injection stability in Table 1, all of the inkjet heads of Comparative Examples 1 to 3 were evaluated as x, which was not good. All of the inkjet heads of Examples 1 to 9 were Δ or more, and favorable evaluation was obtained as compared with the inkjet heads of Comparative Examples 1 to 3. In particular, the ink jet heads of Examples 1 to 7 were all good or better, and better evaluation was obtained. Further, the ink jet head of Example 7 was evaluated as ◎, and the best evaluation was obtained.

  As mentioned above, according to this Embodiment, the manufacturing method of the inkjet head of Examples 1-9 is a process which provides a protective layer to the nozzle substrate by which the ink-repellent process was carried out, and a nozzle to the nozzle substrate to which the protective layer was provided. After the forming step, the protective layer peeling step for peeling the protective layer from the nozzle substrate on which the nozzles are formed, and the protective layer peeling step, the entire surface of the nozzle substrate on the side where ink is ejected is subjected to the parent ink treatment. And a parent ink process. The protective layer is a protective film.

  For this reason, by carrying out a manufacturing process in which the ink repellent treatment is performed on the entire surface of the nozzle substrate that has been subjected to the ink repellent treatment, the remaining ink (the adhesive residue of the protective film) is used. It is possible to reduce the defects and stabilize the yield, and the top plate does not deteriorate against scratches caused by the continuous use environment of the inkjet head, and the mist is generated even in an environment where there is a lot of generated ink mist. Even if it adheres to the part that has been treated with the parent ink, it maintains the state of forming a very thin liquid film, so there is no change in the state of the nozzle surface, and stable ejection characteristics can be obtained even during continuous ink ejection. it can.

  In addition, the manufacturing method of the inkjet head of Examples 1 to 7 includes an assembly process F4 that surrounds the nozzle substrate and attaches to the nozzle substrate a top plate on which ink is discharged from the nozzle. Further, in the parent ink process, at least part of the surface of the top plate where ink is ejected from the nozzles is subjected to the parent ink treatment together with the nozzle substrate. For this reason, even if ink adheres to the portion of the top plate that has been treated with the ink-friendly ink, the state in which a very thin liquid film is formed can be maintained and the occurrence of a liquid pool can be prevented.

  Moreover, the manufacturing method of the inkjet head of Examples 1-9 performs the assembly process F4 in the state in which the protective film was provided to the ink-repellent-treated part (ink-repellent layer) of the nozzle substrate. Therefore, the nozzle can be protected by the protective film, and the adhesive film can prevent the adhesive film from being left behind, thereby reducing the variation in the ejection angle distribution of the inkjet head.

  Moreover, in the manufacturing method of the inkjet head of Examples 1-7, a part of the top plate is an area adjacent to the nozzle substrate among the surfaces located on the side (front direction) of ejecting ink from the nozzles of the top plate. It is. For this reason, even if ink adheres to a portion of the top plate adjacent to the nozzle substrate that has been subjected to the ink-philic treatment, it is possible to maintain a very thin liquid film and prevent the occurrence of liquid pool.

  Further, in the ink jet head manufacturing method of Example 7, the degree of parent ink treatment is changed so that the receding contact angle of the ink on the top plate changes from the outer periphery of the front surface to the side wall of the opening located inside the nozzle substrate. Let For this reason, ink wettability (affinity) is changed from the outer periphery of the front surface of the top plate to the side wall of the opening of the nozzle substrate, and a gradation of wettability is created, so that the ink has been treated with the parent ink. Even if it adheres, the attached ink is easily pulled from the low wettability region to the high region, so that the ink can be collected by the nozzle holes of the nozzle substrate.

  Moreover, in the manufacturing method of the inkjet head of Example 2, 4-7, 9, the top plate has a recess structure part, and the nozzle substrate is arrange | positioned in the position lower than the forefront surface of a top plate. For example, in the inkjet heads 100B, 100D, and 100K shown in FIGS. 6, 8, and 13, the nozzle substrate 11A is disposed at a position lower than the forefront surface (front surface of the convex portion) of the top plates 3B, 3D, and 3K. . Further, in the inkjet heads 100E, 100F, and 100G of FIGS. 9 to 11, the nozzle substrate 11A is positioned lower than the foremost plane that is in contact with the highest portion of the tapered portions 3E1, 3F1, and 3G1 of the top plates 3E, 3F, and 3G. Is arranged. For this reason, since the recording medium or the like and the nozzle substrate are hardly brought into contact with each other by the recess structure portion, the surface of the nozzle substrate can be protected and maintenance durability can be improved as compared with the case without the recess structure portion. Maintenance durability is durability by wipe maintenance. The nozzle substrate may be arranged at a height equal to the top surface of the top plate or at a height higher than the top surface of the top plate.

  Moreover, in the manufacturing method of the inkjet head of Examples 5-7, the recess structure part of a top plate is a taper part which continues gently from the outer periphery of the forefront surface to the side wall of the opening part which positions a nozzle substrate in the inside. For this reason, the ink adhering to the top plate can smoothly flow into the nozzle holes of the nozzle substrate.

  In the ink jet head manufacturing methods of Examples 1 to 9, the parent ink process is a vacuum plasma process. For this reason, it is possible to perform the parent ink process on the entire surface without unevenness.

  In the ink jet head manufacturing methods of Examples 1 to 9, the vacuum plasma treatment is dry etching. Therefore, the parent ink process can be performed in a short time.

  In the ink jet head manufacturing methods of Examples 3 to 7, in the parent ink process, at least a part of the top plate is protected by a protective material, and at least the surface on the side where ink is ejected from the nozzles of the nozzle substrate ( The front ink is treated with the parent ink. For this reason, the parent ink process can be performed more easily and selectively.

  Moreover, in the manufacturing method of the inkjet head of Examples 1-9, the main-body part of an inkjet head is surrounded and protected in a parent ink process by a protective material. For this reason, it is possible to prevent damage to the electrical system of the inkjet head due to the influence of overcurrent generated during dry etching.

  Further, in the manufacturing method of the ink jet head of Example 7, the surface wettability is intermittently changed from the top plate toward the nozzle substrate from ink repellency to ink affinity, and Examples 1 to 6, 8, The continuous ejection stability is higher than the configuration of the inkjet head manufacturing method of No. 9 in which there are few places where the surface wettability changes from the top plate to the nozzle substrate.

  The description in the above embodiment is an example of a preferable method for manufacturing an inkjet head according to the present invention, and the present invention is not limited to this.

  For example, at least two of the configurations of the above embodiments (examples) and the following configurations may be appropriately combined.

  The ink repellent layer in the above embodiment has been described as having a single layer structure, but is not limited thereto. For example, as shown in FIG. 15, the ink repellent layer may have a two-layer structure. FIG. 15 is a cross-sectional view of a nozzle substrate 11A having a two-layer ink repellent layer 1aI.

  An ink repellent layer 1aI having a two-layer structure is formed on the front surface of the nozzle substrate 11A. The ink repellent layer 1aI has a lower binder layer I1 having a binder component and an upper ink repellent component layer I2 having an ink repellent component.

  A fluororesin is used as the substance of the ink repellent component. Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer. (ETFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), and the like can be used, but FEP has a low critical surface tension, excellent ink repellency, and a heat treatment temperature of 300. C. to 400.degree. C. is preferable because the melt viscosity is low and a uniform film can be formed.

  As the material of the binder component, a material that improves the adhesion of the ink repellent layer 1aI to the nozzle substrate 11A is used. As this substance, water-soluble polyamideimide (PAI) is used. Normally PAI does not dissolve in water. For this purpose, PAI was mixed and stirred with a basic compound such as an amine compound in a basic polar solution, and water was gradually added to obtain water-soluble PAI.

  In addition, when a surfactant is added to the coating solution, the adhesion of the film can be improved without lowering the ink repellency of the ink repellent layer, and the durability of the ink repellent layer can be further improved. When polyoxyethylene alkyl ether is used as the surfactant, it is possible to further improve the durability of the ink repellent layer.

  As a coating method for forming the ink repellent layer 1aI, spray coating, spin coating, brush coating, dip coating, wire bar coating, and the like can be used. A good film can be formed, and efficient application is possible. After coating and drying, the coating layer is heat treated. As processing temperature, 300 to 400 degreeC is preferable.

  For example, an aqueous dispersion of FEP and a water-soluble PAI are added to water to prepare a coating solution for one coat. Moreover, you may adjust a coating liquid by adding polyethyleneglycol monododecyl ether to the said coating liquid. In the ink repellent layer 1aI thus formed, the concentrations of the ink repellent component and the binder component continuously change between the upper ink repellent component layer I2 and the lower binder layer I1.

  According to the configuration of the ink repellent layer 1aI, the adhesion of the ink repellent layer to the nozzle substrate 11A can be improved, and the formation of the binder layer I1 can prevent the nozzle substrate from being damaged. The ink repellent layer formed on the top board may be formed in the same manner as the ink repellent layer 1aI.

  Further, the detailed configuration and detailed operation of each part constituting the ink jet recording apparatus 1000 in the above embodiment can be appropriately changed without departing from the spirit of the present invention.

1000 Inkjet recording apparatus 200 Conveying section 210 Unwinding roll 220, 230 Roller 240 Winding roll 300 Image forming section 310 Line head 320 Irradiation section 330 Carriage 330a Carriage heater 400 Ink supply section 410 Ink tank 420 Pump 430 Ink tube 440 Sub tank 440a Float Sensor 450 Ink tube 460 Heater 500 Control unit 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100J, 100K Inkjet head 1 Actuator 11, 11A, 11H Nozzle substrate 11a Nozzle 2 Housing 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3J, 3K Top plate 1a, 3a Front surface 1cA, 3cA, 3cB, 3cC 3cD, 3cE, 3cF, 3cG, 3cG1, 3cG2, 3cG3, 1cH Parent ink regions 3aC, 3aD, 3aE, 3aF, 3aG, 3aJ, 3aK Ink repellent regions 3B1, 3D1 Recessed portions 3E1, 3F1, 3G1 Tapered portions 4, 5 Adhesive Layer b Openings 21, 22, 23, 31, 32, 33, 34, 41 Protective material 1aI Ink-repellent layer I1 Binder layer I2 Ink-repellent component layer

Claims (14)

A protective layer applying step for applying a protective layer to the ink-repellent nozzle substrate;
A nozzle forming step of forming a nozzle on the nozzle substrate provided with the protective layer;
A protective layer peeling step of peeling the protective layer from the nozzle substrate on which the nozzle is formed;
A method of manufacturing an inkjet head having
A method for manufacturing an ink jet head, comprising: after the protective layer peeling step, a parent ink step of treating the entire surface of the nozzle substrate on a side where ink is ejected from the nozzle, with a parent ink treatment.   The inkjet head manufacturing method according to claim 1, further comprising an assembling step of attaching to the nozzle substrate a top plate that surrounds the nozzle substrate and has an ink repellent treatment on a surface on which ink is ejected from the nozzle. Method.   3. The method of manufacturing an ink jet head according to claim 2, wherein the assembling step is performed in a state where the protective layer is applied to a portion of the nozzle substrate that has been subjected to ink repellent treatment.   4. The ink-philic process according to claim 2, wherein at least a part of a surface of the top plate on which ink is ejected from the nozzle is subjected to ink-philic treatment together with the nozzle substrate in the ink-philic step. 5. A method for manufacturing an inkjet head. A part of the top plate is
5. The inkjet head according to claim 2, wherein the surface of the top plate is a region adjacent to the nozzle substrate in a surface located on a direction side in which ink is ejected from the nozzles. 6. Production method.   3. In the parent ink step, the degree of parent ink processing is changed so that the receding contact angle of ink on the top plate changes from the outer periphery of the forefront to the side wall of the opening in which the nozzle substrate is located. The method for producing an ink jet head according to claim 5. The top plate has a recess structure,
The method for manufacturing an ink jet head according to claim 2, wherein the nozzle substrate is disposed at a position lower than a forefront surface of the top plate.   8. The method of manufacturing an ink jet head according to claim 7, wherein the recess structure portion is a tapered portion that is gently continuous from the outer periphery of the forefront surface to the side wall of the opening portion in which the nozzle substrate is located. In the lyophilic process, while protecting at least a portion of the top plate with a protective material, any one of claims 2 to 8 in which the ink from the nozzle of at least the nozzle substrate is ink affinity handle surface on the side to be discharged The manufacturing method of the inkjet head of one term. The method for manufacturing an inkjet head according to any one of claims 1 to 9, wherein in the parent ink step, the main body of the inkjet head is surrounded and protected by a protective material . The nozzle substrate has an ink repellent layer,
The ink repellent layer has a lower binder layer having a binder component and an upper ink repellent component layer having an ink repellent component, and the concentration of the ink repellent component and the binder component is between the upper layer and the lower layer. The method for manufacturing an inkjet head according to claim 1, wherein the inkjet head is continuously changed . The protective layer, ink jet head manufacturing method according to any one of claims 1 to 11, characterized in that a protective film. The ink affinity process, ink jet head manufacturing method claimed in any one of 12, which is a vacuum plasma treatment. The method of manufacturing an inkjet head according to claim 13 , wherein the vacuum plasma treatment is dry etching .

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