JP7341876B2 - Inkjet head discharge inspection method - Google Patents

Description

The present invention relates to an inkjet head ejection testing method for testing the ejection state of nozzles included in the inkjet head .

In recent years, manufacturing of various devices such as display panels such as liquid crystal and organic EL, various sensors such as glucose sensors, wearable devices, and optical components such as lenses and light guide plates using manufacturing equipment having inkjet heads has been considered. For example, Japanese Patent Laid-Open No. 2003-191462 discloses a method for manufacturing a color filter or an organic EL using a drawing device having an inkjet head, a method for forming a spacer, a method for forming a metal wiring, a method for forming a lens, a method for forming a resist, and a method for forming a light diffuser. A forming method and the like are disclosed.

The inks used in the drawing equipment used to manufacture these various devices include not only color inks containing coloring materials, but also UV curing inks, semiconductor inks, metal inks, insulator inks, dielectric inks, and conductive polymer inks. Functional inks containing various functional substances are used, such as resin ink, liquid crystal ink, etc. In addition, drawing devices used to manufacture various devices often eject only one type of ink with a specific function, and replacing it with a different type of ink poses problems such as quality deterioration due to contamination. This is not normally done as this would occur.

Generally, after manufacturing an inkjet head, the discharge from the nozzles is inspected to confirm that there are no defects, and then the head is delivered to a drawing device manufacturer. Inkjet head discharge testing is performed by printing a pattern such as a line consisting of dots corresponding to individual nozzles or a collection of dots on an inkjet device testing medium. If there is an ejection failure in the nozzle, the above-mentioned pattern or the like will be missing, so this condition is converted into data using a digital camera or the like and mechanically inspected. For example, in Japanese Unexamined Patent Application Publication No. 2014-94534 (Patent Document 1), there is disclosed that a functional liquid is discharged onto a recording medium for inspection that has a permeation layer that permeates the functional liquid and a reflective layer formed on one surface of the permeation layer. A method for imaging the dot shape of a functional fluid is disclosed. However, such testing methods require testing with a functional liquid that is different from the ink used to manufacture various devices, and when actually manufacturing various devices, performance deterioration due to contamination may occur. There was a problem with putting it away.

Testing for ink that does not cause problems even if the above contamination occurs, is mainly composed of volatile solvents contained in color inks and functional inks used in the manufacture of various devices, and does not substantially contain components such as coloring materials. An example is ink for.

However, when using a test ink that contains the above-mentioned volatile solvent as a main component and does not substantially contain components such as colorants, there is a problem in that it is difficult to perform ejection tests using conventional inkjet device testing media. Ta.

For example, Japanese Patent Laid-Open No. 2006-88466 (Patent Document 2) states that the density difference between a colorless or light-colored ink-attached area and a non-adhered area is 0.02 or more, and in the L ^* a ^* b ^* color system, A method using a film for liquid confirmation having a ΔE of 10.0 or less is disclosed, and a film whose surface is roughened with sandpaper is described as the film for liquid confirmation. Patent Document 1 discloses an inspection recording medium that has an ink permeation layer and a reflective layer that reflects light on one surface of the permeation layer, and the permeation layer contains silica, alumina, etc. It is a transparent void layer, and the reflective layer is formed on the permeable layer by depositing aluminum, silver, etc. Further, JP-A-2014-113797 (Patent Document 3) discloses an inspection medium that includes an ink-receiving layer that swells by absorbing ink and bulges in the thickness direction. However, even if a discharge test is performed on the liquid confirmation film, test recording medium, or test media described above using a test ink that is mainly composed of a volatile solvent and does not substantially contain components such as colorants, However, it was difficult to perform a smear test because no trace remained after the test ink evaporated and dried.

Japanese Patent Application Publication No. 2014-94534 Japanese Patent Application Publication No. 2006-88466 Japanese Patent Application Publication No. 2014-113797

The present invention provides an inkjet head ejection inspection method that enables appropriate ejection inspection even when using a test ink that is mainly composed of a volatile solvent and does not substantially contain components such as colorants. It provides:

The above objects of the present invention have been basically achieved by the following invention.
On a transparent support, a porous layer containing at least fine particles, a resin binder, and an aliphatic compound having substantially no vapor pressure at room temperature is provided. An inkjet head ejection inspection method that prints a test ink whose main component is a solvent and does not substantially contain coloring material, uses image data to trace traces of the printed part, and detects these traces using image processing software.

According to the present invention, the ejection of an inkjet head enables appropriate ejection testing even when using a test ink that is mainly composed of a volatile solvent and does not substantially contain components such as coloring material. An inspection method can be provided.

The present invention will be explained in detail below.

The inkjet device inspection medium used in the inkjet head ejection inspection method of the present invention is a porous medium containing at least fine particles, a resin binder, and an aliphatic compound having substantially no vapor pressure at room temperature on a transparent support. It has layers.

A method for testing the ejection of an inkjet head using the inkjet device testing media of the present invention is to apply a volatile solvent as a main component and substantially no components such as a coloring material onto a porous layer of the inkjet device testing media. A test ink that does not contain any organic matter is printed, the traces of the printed part are used as image data, and these traces are detected by image processing software .

In the present invention, the porous layer of the inkjet device testing medium can quickly absorb the test ink that is ejected from the inkjet head and contains a volatile solvent as a main component. When the ink evaporates, the total light transmittance of the porous layer in the part that had absorbed the ink increases, and the total light transmittance decreases in the area around the part that had absorbed the ink. manifest.

The above phenomenon will be explained in more detail. In the present invention, the porous layer of the inkjet device testing medium contains an aliphatic compound that has substantially no vapor pressure at room temperature. The aliphatic compound has the effect of changing the total light transmittance of the porous layer, and as the content increases, the total light transmittance tends to decrease.

In the present invention, when one or more droplets of test ink are ejected from the inkjet head onto the media for testing an inkjet device and dots are formed, the ink droplets are absorbed into the porous layer and volatilized. The organic solvent dissolves the aliphatic compound contained in the porous layer, that is, the aliphatic compound that has substantially no vapor pressure at room temperature. The volatile solvent in which the aliphatic compound is dissolved diffuses inside the porous layer to the periphery of the dots, and at the same time, volatilization progresses from the dot portions and the areas around the diffused dots. As a result, aliphatic compounds in the dots decrease (total light transmittance at the center of the dot becomes high), and aliphatic compounds increase at the periphery of the dots (total light transmittance at the dot periphery becomes low). Even if the test ink does not contain a coloring material or the like, traces of printed dots are formed on the inkjet device testing media, and the traces of dots remain even after the volatile solvent of the test ink evaporates and dries.

In the present invention, examples of the volatile solvent contained in the test ink include known organic solvents having a vapor pressure that evaporates at room temperature. For example, aromatic organic solvents include benzene, toluene, xylene, mesitylene, ethylbenzene, linear or branched propylbenzene, butylbenzene, pentylbenzene, hexylbenzene, nonylbenzene, decylbenzene, undecylbenzene, dodecylbenzene, Examples include tetralin and cyclohexylbenzene. Examples of the halogenated organic solvent include dichloromethane, dichloroethane, chloroform, carbon tetrachloride, tetrachloroethane, trichloroethane, chlorobenzene, dichlorobenzene, and chlorotoluene. Examples of the ether organic solvent include diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, dioxane, anisole, and 3-phenoxytoluene. Examples of hydrocarbon-based organic solvents include straight-chain or branched, saturated or unsaturated hydrocarbons having 6 or more carbon atoms, such as hexane, heptane, octane, nonane, decane, and undecane. Examples of the ester organic solvent include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, octyl acetate, methyl propionate, and ethyl propionate. Examples of ketone organic solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of alcoholic organic solvents include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, and fluorinated alcohol. These organic solvents may be used alone or in combination of two or more. Furthermore, when the volatile solvent contained in the test ink is an organic solvent that evaporates slowly, the inkjet device testing medium after printing is heated to evaporate it.

In the present invention, the test ink preferably contains the above-mentioned volatile solvent as a main component. Here, the term "main component" means that the proportion of the volatile solvent described above is 95% by mass or more, preferably 99% by mass or more, and more preferably 99% by mass, based on the total mass of the test ink. It is 5% by mass or more, and particularly preferably 100% by mass. Examples of compounds included in the ink other than the volatile solvent include surfactants, rheology control agents (thickeners) such as polymers and bentonite, and test inks containing substantially no colorants are preferred. Here, "substantially" means that the content of coloring components represented by colorants is less than 0.1% by mass, more preferably less than 0.01% by mass.

In the present invention, the transparent support included in the inkjet device inspection media is preferably a transparent support having a total light transmittance of 85% or more and a haze value of 30% or less, such as a polyolefin-based support such as polyethylene, polypropylene, etc. Resins, polyvinyl chloride, vinyl chloride resins such as vinyl chloride copolymers, acrylic resins such as polyethylene terephthalate, polyethylene naphthalate, and polymethyl methacrylate, triacetyl cellulose, cellophane, nylon, polystyrene resins, epoxy resins, Examples include various resin films such as phenoxy resin, fluororesin, polycarbonate, polyarylate, polysulfone, polyethersulfone, polyimide, and polyphenylene sulfide. Among these, resin films selected from triacetyl cellulose, polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, and polycarbonate are preferred from the viewpoint of cost and versatility.

In order to improve the adhesion of the porous layer to the transparent support, the transparent support may have a known undercoat layer containing gelatin, various urethane resins, polyvinyl alcohol, etc. to improve the adhesion in advance. It is also possible to use a product treated to facilitate adhesion (for example, a polyethylene terephthalate film treated to facilitate adhesion) provided with a layer for this purpose. It is also preferable to improve the wettability of the transparent support by corona treatment or plasma treatment.

The solid content of the above-mentioned undercoat layer is preferably 0.5 g/m ² or less, more preferably 0.3 g/m ² or less, still more preferably 0.1 g/m ² or less. It is desirable that the lower limit is 0.01 g/m ² or more.

In the present invention, the porous layer of the inkjet device testing medium contains at least fine particles, a resin binder, and an aliphatic compound that has substantially no vapor pressure at room temperature.

As the fine particles contained in the porous layer, a wide variety of known fine particles can be used. For example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, Amorphous synthetic silica, alumina, colloidal alumina, alumina hydrate, lithopone, zeolite, hydrated halloysite, inorganic fine particles such as magnesium hydroxide, acrylic or methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyester resin , styrene/acrylic resin, styrene/butadiene resin, styrene/isoprene resin, methyl methacrylate/butyl methacrylate resin, polycarbonate resin, silicone resin, urea resin, melamine resin, epoxy resin, phenol resin, Examples include organic fine particles such as diallyl phthalate resin. Examples of the organic fine particles include true spherical or amorphous non-porous or porous organic fine particles made of at least one of the above resins. Of course, it is also possible to contain one or more of the above-mentioned inorganic fine particles and one or more of the organic fine particles. Among the above-mentioned fine particles, it is preferable to contain inorganic fine particles from the viewpoint of absorption of the volatile solvent mentioned above, such as light calcium carbonate, heavy calcium carbonate, kaolin, talc, magnesium carbonate, amorphous synthetic silica, alumina, Alumina hydrate is more preferred, and amorphous synthetic silica, alumina, and alumina hydrate are particularly preferred. Furthermore, when flexibility is required for the media for testing inkjet devices, alumina hydrate is suitable.

In order to form a porous layer using fine particles, the proportion of the fine particles in the total solid content of the porous layer is preferably 50% by mass or more, more preferably 60% by mass or more. A porous layer having such a high proportion of fine particles is preferable because it has excellent absorption of volatile solvents contained in the test ink.

Among the above-mentioned fine particles, fine particles having an average particle size of 500 nm or less (fine particles formed by agglomerating primary particles to form secondary particles have an average secondary particle size of 500 nm or less) are preferable. A porous layer containing such fine particles can more easily overcome the phenomenon that the total light transmittance increases in the area that has absorbed the test ink, and that the total light transmittance decreases in the peripheral area of the area that has absorbed the ink. It is preferable because it can be detected.

Amorphous synthetic silica can be broadly classified into wet process silica, vapor phase process silica, and others depending on the manufacturing method. Wet process silica is further classified into precipitated process silica, gel process silica, and sol process silica, depending on the manufacturing method. In the present invention, as the wet silica contained in the porous layer, it is preferable to use precipitated silica or gel silica, and precipitated silica is more preferable. Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the grown silica particles coagulate and precipitate, followed by filtration, water washing, drying, pulverization, and classification to become a product. Examples of precipitated silica include Nip Seal (registered trademark) from Tosoh Silica Co., Ltd., Tokusil (registered trademark) and Fine Seal (registered trademark) from Maruo Calcium Co., Ltd., and Mizukasil (registered trademark) from Mizusawa Chemical Industry Co., Ltd. It is commercially available as a registered trademark. Gel method silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During ripening, the microparticles dissolve and re-precipitate to bond with other primary particles, so that distinct primary particles disappear and relatively hard agglomerated particles with an internal void structure are formed. Examples of gel method silica include Nipgel (registered trademark) from Tosoh Silica Co., Ltd., Siloid (registered trademark) and Silojet (registered trademark) from GCP Japan Co., Ltd., and Mizukasil from Mizusawa Chemical Industry Co., Ltd. It is commercially available.

The wet process silica used in the present invention preferably has an average primary particle size of 50 nm or less, more preferably 3 to 40 nm, and has an average secondary particle size of 500 nm or less, more preferably an average The secondary particle diameter is 20 to 300 nm. The wet process silica is preferably used in the form of a wet process silica fine particle dispersion which is pulverized and dispersed in an aqueous medium. As the pulverization method, a wet dispersion method in which wet silica particles are mechanically pulverized is preferably used, and a media mill such as a bead mill is preferably used for this purpose. Bead mills perform pulverization by colliding with beads filled in a sealed vessel, and are manufactured by Willy & Bakchoven as Dyno Mill, Asada Iron Works Co., Ltd. as Glen Mill (registered trademark), and Ashizawa Finetech. It is commercially available as Star Mill (registered trademark) from Co., Ltd. Specifically, wet process silica and an aqueous medium are premixed using a propeller blade type stirrer, sawtooth blade type stirrer, homomixer type stirrer, etc., and then the wet process silica is ground using a media mill. It is preferable to use a silica fine particle dispersion. Furthermore, it is also preferable to grind the particles using a pressure type disperser such as a high-pressure homogenizer or an ultra-high-pressure homogenizer, an ultrasonic disperser, a thin-film swirl type disperser, or the like to obtain a wet-process silica fine particle dispersion.

The average primary particle diameter as used in the present invention is the average particle diameter determined by electron microscopy of fine particles, with the diameter of a circle equal to the projected area of each of 100 primary particles existing within a certain area being the diameter of the particle. . The average secondary particle diameter can be determined by taking a photograph using a transmission electron microscope, but it can be simply determined by using a laser scattering particle size distribution analyzer (for example, LA910 manufactured by Horiba, Ltd.) or using a dynamic light beam. It can be measured as a number median diameter using a scattering type particle size distribution analyzer (for example, PAR-III manufactured by Otsuka Electronics Co., Ltd.).

Vapor-phase silica is also called a dry method as opposed to a wet method, and is generally produced by a flame hydrolysis method. Specifically, it is generally known that silicon tetrachloride is produced by burning it together with hydrogen and oxygen, but instead of silicon tetrachloride, silanes such as methyltrichlorosilane and trichlorosilane can be used alone or with silicon tetrachloride. It can be used in a mixed state. Vapor-phase silica is commercially available as Aerosil (registered trademark) from Nippon Aerosil Co., Ltd. and Rheolosil (registered trademark) from Tokuyama Co., Ltd.

In the present invention, the average primary particle diameter of the vapor-grown silica contained in the porous layer is preferably 40 nm or less, more preferably 15 nm or less. More preferably, particles having an average primary particle diameter of 3 to 15 nm and a specific surface area of 200 m ² /g or more (preferably 250 to 500 m ² /g) by BET method are used.

The BET method used in the present invention is a method for measuring the surface area of powder using a gas phase adsorption method, and is a method for determining the total surface area, that is, the specific surface area, of 1 g of a sample from an adsorption isotherm. Nitrogen gas is usually used as the adsorbed gas, and the most commonly used method is to measure the adsorbed amount from changes in the pressure or volume of the adsorbed gas. The most well-known equation representing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller equation, which is called the BET equation and is widely used for determining surface area. The amount of adsorption is determined based on the BET formula, and the surface area is obtained by multiplying the amount by the area occupied by one adsorbed molecule on the surface.

When vapor phase silica is used, the average secondary particle size is preferably 500 nm or less, more preferably 10 to 300 nm. Vapor-phase silica is used in the form of a dispersion of vapor-phase silica fine particles dispersed in an aqueous medium. Specifically, after pre-mixing vapor phase silica and an aqueous medium using a propeller blade type stirrer, a sawtooth blade type stirrer, a homomixer type stirrer, etc., a media mill such as a ball mill, a bead mill, a sand grinder, etc. It is preferable to disperse using a pressure type disperser such as a high-pressure homogenizer or an ultra-high-pressure homogenizer, an ultrasonic disperser, a thin-film swirl type disperser, or the like to obtain a vapor-phase silica fine particle dispersion.

In the present invention, when producing the above-mentioned wet-process silica fine particle dispersion or vapor-phase silica fine particle dispersion having an average secondary particle diameter of 500 nm or less, various known methods are used to increase the concentration and improve the dispersion stability of the dispersion. You may also use this method. For example, alkaline compounds, cationic compounds, or silane coupling agents described in JP-A-2002-144701 and JP-A-2005-1117 can be used, but it is more preferable to use cationic compounds. preferable.

As the above-mentioned cationic compounds, polyethyleneimine, polydiallylamine, polymers having structural units derived from diallylamine derivatives, polyallylamine, alkylamine polymers, and polymers having primary to tertiary amino groups or quaternary ammonium bases are preferably used. It will be done. In particular, polymers having structural units derived from diallylamine derivatives are preferably used. In view of the dispersibility and dispersion viscosity of the wet process silica or gas phase process silica, the molecular weight of these cationic compounds is preferably about 2,000 to 100,000, particularly preferably about 2,000 to 30,000.

In the present invention, the alumina preferably contained in the porous layer is preferably γ-alumina, which is a γ-type crystal of aluminum oxide, and among them, δ group crystal is preferable. Although primary particles of γ-alumina can be made as small as about 10 nm, it is usually produced by pulverizing secondary particle crystals of several thousand to tens of thousands of nm using ultrasonic waves, high-pressure homogenizers, opposed-impingement jet crushers, etc. can be used. The average secondary particle diameter of alumina is preferably 500 nm or less, more preferably 20 to 300 nm.

In the present invention, the alumina hydrate preferably contained in the porous layer is represented by the constitutional formula Al ₂ O ₃ ·nH ₂ O (n=1 to 3). Alumina hydrate is generally obtained by known production methods such as hydrolysis of aluminum alkoxide such as aluminum isopropoxide, neutralization of aluminum salt with alkali, and hydrolysis of aluminate. The average secondary particle diameter of the alumina hydrate is preferably 500 nm or less, more preferably 20 to 300 nm.

In the present invention, the above alumina and alumina hydrate preferably contained in the porous layer are dispersed with a known dispersant such as acetic acid, lactic acid, formic acid, nitric acid, etc., to form an alumina fine particle dispersion liquid and alumina hydrate fine particles. Preferably it is used in the form of a dispersion.

In the present invention, examples of the resin binder contained in the porous layer include polyvinyl alcohol, various modified polyvinyl alcohols such as silanol-modified, silyl-modified, cationic group-modified, diacetone acrylamide-modified and acetoacetyl-modified, oxidized starch, and ether. modified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, natural polymer compounds such as casein, gelatin, and soybean protein, conjugated diene copolymer latex such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, Alternatively, latexes such as functional group-modified polymer latexes using monomers containing functional groups such as carboxyl groups of these various polymers, melamine resins, urea resins, polymethyl methacrylate, polyurethane resins, unsaturated polyester resins, and vinyl chloride resins. Examples include synthetic resin adhesives such as vinyl acetate copolymer, polyvinyl butyral, and alkyd resin, and these can be used alone or in combination. In addition, there are no particular limitations on the use of known natural or synthetic resin binders alone or in combination.

Among these, partially saponified or completely saponified polyvinyl alcohol, silanol-modified polyvinyl alcohol, and acetoacetyl-modified polyvinyl alcohol with a saponification degree of 80% or more are preferred. The average degree of polymerization of these polyvinyl alcohols is preferably 200 to 5,000.

The content of the resin binder with respect to the fine particles is not particularly limited, but in order to form a porous layer using the fine particles, the content of the resin binder is preferably 3 to 80% by mass, more preferably with respect to the fine particles. is in the range of 5 to 50% by mass.

In the present invention, when the resin binder contained in the porous layer has hardening properties (crosslinking properties), it is preferable that the porous layer contains a hardening agent for the resin binder. Specific examples of hardening agents include sodium glyoxylate, formaldehyde, acetaldehyde, glyoxal, aldehyde compounds such as glutaraldehyde, ketone compounds such as diacetyl and chlorpentanedione, bis(2-chloroethyl)urea, and 2-hydroxy. -4,6-dichloro-1,3,5-triazine, zirconium chloride, zirconium bromide, polyvalent metal compounds such as titanium acetylacetate, amine compounds such as ethylenediamine, hexamethylenediamine, diethylenetriamine, adipic acid dihydrazide, maleic acid dihydrazide, hydrazine compounds such as 1,3-bis(hydrazinocarbonoethyl)-5-isopropylhydantoin, compounds with reactive halogens such as those described in U.S. Pat. No. 3,288,775, U.S. Pat. No. 3,635 , 718, N-methylol compounds as described in U.S. Pat. No. 2,732,316, isocyanates as described in U.S. Pat. No. 3,103,437, U.S. Pat. Aziridine compounds as described in No. 3,017,280 and No. 2,983,611, carbodiimide compounds as described in U.S. Pat. No. 3,100,704, and carbodiimide compounds as described in U.S. Pat. No. 3,091,537. Examples include epoxy compounds, dioxane derivatives such as dihydroxydioxane, and inorganic crosslinking agents such as borax, boric acid, and borates, and these may be used alone or in combination of two or more. Although the content of the hardener is not particularly limited, it is preferably 50% by mass or less, more preferably 40% by mass or less, particularly preferably 30% by mass or less, based on the resin binder. The lower limit is preferably 0.1% by mass or more.

When partially saponified or completely saponified polyvinyl alcohol or silanol-modified polyvinyl alcohol with a saponification degree of 80% or more is used as the resin binder, the hardening agent is preferably borax, boric acid, or borates, and boric acid is particularly preferred. preferable. The amount of these hardeners used is preferably 40% by mass or less, more preferably 30% by mass or less, particularly preferably 20% by mass or less, based on the polyvinyl alcohol. The lower limit is preferably 0.1% by mass or more.

In the present invention, examples of the aliphatic compound contained in the porous layer and having substantially no vapor pressure at room temperature include aliphatic hydrocarbons, aliphatic alcohols, fatty acids, fatty acid esters, and the like. "Having substantially no vapor pressure at room temperature" means that the vapor pressure of the aliphatic compound at 25° C. is 1 Pa or less, and a more preferable vapor pressure is 0.1 Pa or less.

Examples of aliphatic hydrocarbons include various alkanes, alkenes, and alkynes, and among them, alkanes having 17 or more carbon atoms are preferred, and examples include n-heptadecane, n-octadecane, and n-nonadecane. Note that the vapor pressure of these compounds at 25° C. is 0 Pa.

As the aliphatic alcohol, higher alcohols having 14 or more carbon atoms are preferred, and examples thereof include myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, myricyl alcohol, and the like. Note that the vapor pressure of these compounds at 25° C. is 0 Pa.

As the fatty acid, higher fatty acids having 12 or more carbon atoms are preferred, and examples thereof include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid. Note that the vapor pressure of these compounds at 25° C. is 0 Pa.

As the fatty acid ester, higher fatty acid esters having 16 or more carbon atoms are preferred, and examples thereof include methyl palmitate, methyl stearate, butyl stearate, and methyl arachidate. Note that the vapor pressure of these compounds at 25° C. is 0 Pa.

These aliphatic compounds can be used in combination. In particular, solid paraffin, which is a mixture of alkanes having 16 or more carbon atoms, is preferred in terms of availability and price. Solid paraffin is commercially available, for example, from Nippon Seiro Co., Ltd. as a paraffin wax series.

In the present invention, the content of the aliphatic compound that has substantially no vapor pressure at room temperature in the porous layer is not particularly limited, but it can achieve the effects of the present invention and absorb the test ink in the porous layer. In order to secure voids for the porous layer, the proportion of the aliphatic compound having substantially no vapor pressure at room temperature in the total solid content of the porous layer is preferably 3 to 40% by mass, more preferably It is in the range of 10 to 30% by mass.

In addition, the porous layer may contain preservatives, surfactants, ultraviolet absorbers, antioxidants, fine particle dispersants, antifoaming agents, leveling agents, viscosity stabilizers, pH regulators, etc., as necessary. can. The solid content of the porous layer is preferably 1 to 100 g/m ² , more preferably 3 to 50 g/m ² .

In forming the above-mentioned porous layer on a transparent support, the porous layer is formed by preparing a coating solution containing the above-mentioned components, coating the coating solution on the transparent support, and drying it. , is convenient and preferable. On the other hand, depending on the content of the aliphatic compound described above, coating failure may occur due to the coating liquid containing the aliphatic compound. In order to avoid such problems, a porous layer is formed by applying a coating liquid containing at least fine particles and a resin binder onto a transparent support and drying it to form a porous fine particle-containing layer. Preferably, the layer is formed by a two-step process of applying a coating liquid containing an aliphatic compound having substantially no vapor pressure at room temperature to the layer and drying it.

In the first step, in which a coating liquid containing at least fine particles and a resin binder is coated on a transparent support and dried, the fine particles and resin binder, etc. are dissolved or dispersed in an appropriate solvent such as water, and as necessary. Depending on the requirements, an organic solvent, a leveling agent, a coloring dye, a surfactant, etc. are added to prepare a coating solution for forming a layer containing fine particles, and the coating solution for forming a layer containing fine particles is applied onto a transparent support and dried to form a layer containing fine particles. form. Various coating methods include slide curtain method, slide bead method, slot die method, direct gravure roll method, reverse gravure roll method, spray method, air knife method, blade coating method, rod bar coating method, and spin coating method. is exemplified.

Next, in the second step, an aliphatic compound coating solution is prepared by heating and/or dissolving the aliphatic compound in an appropriate organic solvent, and the aliphatic compound coating solution is applied to the fine particle-containing layer formed in the first step. is applied and dried to form the porous layer of the present invention. Application methods include slide curtain method, slide bead method, slot die method, direct gravure roll method, reverse gravure roll method, spray method, air knife method, blade coating method, rod bar coating method, spin coating method, inkjet method, etc. Various coating methods are exemplified.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the content of the present invention is not limited to the Examples. Furthermore, in Examples and Comparative Examples, "parts" and "%" indicate parts by mass and mass % of solid content or substantial components unless otherwise specified.

(Preparation of inkjet device inspection medium 1)
2.5 parts of nitric acid and 100 parts of alumina hydrate (average primary particle size 15 nm) were added to water, and a sawtooth blade type dispersion machine was used to obtain inorganic fine particle dispersion 1 with a solid content concentration of 30%. . The average secondary particle diameter of the alumina hydrate dispersed in the inorganic fine particle dispersion was 160 nm. Using this inorganic fine particle dispersion 1, a fine particle-containing layer forming coating liquid having the following composition was prepared.

<Fine particle-containing layer forming coating liquid>
Inorganic fine particle dispersion 1 (as solid content of inorganic fine particles) 100 parts Polyvinyl alcohol 9 parts (saponification degree 88%, average degree of polymerization 3500, molecular weight approximately 150,000)
Boric acid 0.5 part The solid content concentration was adjusted with water to 16%.

As a transparent support, the above fine particle-containing layer forming coating solution was applied to a 100 μm thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, total light transmittance 89%, haze value 6%) that had been treated to facilitate adhesion, and the solid content was The powder was coated using a slide bead coater to give a weight of 20.0 g/m ² and dried to form a fine particle-containing layer.

Next, aliphatic compound coating liquid 1 having the following composition was applied to the surface of the fine particle-containing layer using a reverse gravure roll coating device so that the solid content of the aliphatic compound was 3.6 g/m ² . After coating, it was dried to obtain a media 1 for testing an inkjet device according to an example having a porous layer of the present invention. The proportion of the aliphatic compound in the total solid coating amount of the porous layer containing the aliphatic compound was 15.3%.

<Aliphatic compound coating liquid 1>
n-Heptane 100.0 parts Paraffin Wax 115 (solid paraffin) 47.0 parts (manufactured by Nippon Seiro Co., Ltd., vapor pressure 0 Pa at 25°C)
N-heptane was added to the heated and melted solid paraffin and dissolved.

(Preparation of inkjet device inspection medium 2)
In producing the media 1 for inkjet device testing, the aliphatic compound coating liquid 1 was changed to the aliphatic compound coating liquid 2 having the following composition, and a reverse gravure roll was used so that the solid content of the aliphatic compound was 6.6 g/ ^m2 . An inkjet device testing medium 2 of the example was obtained in the same manner except that the coating was performed using a coating device. The proportion of the aliphatic compound in the total solid coating amount of the porous layer containing the aliphatic compound was 24.8%.

<Aliphatic compound coating liquid 2>
n-heptane 100.0 parts Paraffin Wax 115 121.9 parts n-heptane was added to the heated and melted solid paraffin and dissolved.

(Preparation of inkjet device inspection medium 3)
In producing the media 1 for inkjet device inspection, the aliphatic compound coating liquid 1 was changed to the aliphatic compound coating liquid 3 having the following composition, and a reverse gravure roll was used so that the solid content of the aliphatic compound was 3.6 g/ ^m2 . An inkjet device testing medium 3 of the example was obtained in the same manner except that the coating was performed using a coating device. The proportion of the aliphatic compound in the total solid coating amount of the porous layer containing the aliphatic compound was 15.3%.

<Aliphatic compound coating liquid 3>
Ethyl alcohol 100.0 parts Cetyl alcohol 43.0 parts

(Preparation of inkjet device inspection medium 4)
In producing the media 1 for inkjet device inspection, the aliphatic compound coating liquid 1 was changed to the aliphatic compound coating liquid 4 having the following composition, and a reverse gravure roll was used so that the solid content of the aliphatic compound was 3.6 g/ ^m2 . An inkjet device testing medium 4 of the example was obtained in the same manner except that the coating was performed using a coating device. The proportion of the aliphatic compound in the solid coating amount of the porous layer containing the aliphatic compound was 15.3%.

<Aliphatic compound coating liquid 4>
Ethyl alcohol 100.0 parts Myristyl alcohol 43.0 parts

(Preparation of inkjet device inspection medium 5)
In producing the media 1 for inkjet device testing, the aliphatic compound coating liquid 1 was changed to the aliphatic compound coating liquid 5 having the following composition, and reverse gravure roll was applied so that the solid content of the aliphatic compound was 1.0 g/ ^m2 . An inkjet device testing medium 5 of the example was obtained in the same manner except that the coating was performed using a coating device. The proportion of the aliphatic compound in the total solid coating amount of the porous layer containing the aliphatic compound was 4.8%.

<Aliphatic compound coating liquid 5>
n-heptane 100.0 parts Paraffin Wax 115 10.5 parts n-heptane was added to the heated and melted solid paraffin and dissolved.

(Preparation of media 6 for inkjet device inspection)
Inkjet device testing media 6 as a comparative example was obtained in the same manner as in the production of inkjet device testing media 1 except that aliphatic compound coating liquid 1 was not applied.

<Inkjet printing 1>
The above-mentioned inkjet device testing media 1 to 4, and 6 were each cut into A4 size, and a volatile solvent (3-phenoxytoluene) was used as the test ink. Using a DMP-2831 manufactured by Fuji Film Corporation equipped with an on-demand inkjet head using a piezo drive system manufactured by Matix, a droplet of about 10 pL was ejected once to print one dot. In the same manner, a total of 20 dots were printed at discrete positions, and then left to dry at room temperature for 48 hours.

<Inkjet printing 2>
Cut each of the above inkjet device testing media 1 to 4 and 6 into A4 size pieces, and use a volatile solvent (methyl ethyl ketone) as the test ink to eject a droplet of about 10 pL once using the piezo type inkjet printer mentioned above. Then, one dot was printed. In the same manner, a total of 20 dots were printed at discrete positions, and then left to dry at room temperature for 48 hours.

<Inkjet printing 3>
Cut each of the above inkjet device testing media 1 to 4 and 6 into A4 size pieces, and use a volatile solvent (toluene) as the test ink to eject a droplet of about 10 pL once using the piezo type inkjet printer mentioned above. Then, one dot was printed. In the same manner, a total of 20 dots were printed at discrete positions, and then left to dry at room temperature for 48 hours.

<Inkjet printing 4>
The above inkjet device testing media 5 and 6 are each cut into A4 size, and using a volatile solvent (3-phenoxytoluene) as the test ink, approximately 10 pL droplets are placed at the same position using the piezo type inkjet printer described above. One dot was printed by ejecting nine times in succession. In the same manner, a total of 20 dots were printed at discrete positions, and then left to dry on a 60° C. hot stage for 48 hours.

<Evaluation of visibility>
Each dot (range including the printing position of each dot) printed on media 1 to 6 for inkjet device inspection was photographed using a digital microscope (VHX-5000 manufactured by Keyence Corporation) at a magnification of 500 times and with transmitted illumination. , image data of each dot was obtained. Next, dot detection was performed on the image data using image processing software (WIL-Builder manufactured by First Co., Ltd.). The results are shown in Tables 1 and 2.
Good: All 20 printed dots could be detected.
Δ: Among 20 printed dots, 1 to 19 dots could not be detected.
x: All 20 printed dots could not be detected.

From the results in Tables 1 and 2, it is clear that in the inkjet head ejection testing method of the present invention, dots are formed using a test ink that contains a volatile solvent as a main component and does not substantially contain components such as coloring material. It is possible to detect and perform discharge inspection.

Claims (1)

On the porous layer of the media for inkjet device testing, which has a porous layer on a transparent support that contains at least fine particles, a resin binder, and an aliphatic compound that has substantially no vapor pressure at room temperature, a volatile An inkjet head ejection inspection method that prints with a test ink that contains a solvent as a main component and does not substantially contain coloring material, uses image data as traces of the printed portion, and detects these traces using image processing software.