JP2023101104A - Inkjet ink composition and recording method - Google Patents

Abstract

To provide an inkjet ink composition that has high friction fastness, is less prone to deposit on ink channel members, and ensures easy cleaning of a nozzle face.SOLUTION: An inkjet ink composition is used in an inkjet recording device which includes an ink channel including at least a component composed of silicone elastomer or thermoplastic elastomer. The inkjet ink composition includes a specific pigment, specific resin particles, a specific glycol solvent, a specific metal hydroxide, a specific amine compound, and water, at specific ratios.SELECTED DRAWING: None

Description

The present invention relates to an inkjet ink composition and a recording method.

The inkjet recording method is a method in which droplets of an inkjet ink composition are ejected from fine nozzles and adhered to a recording medium for recording. This method is characterized in that high-resolution, high-quality images can be recorded at high speed with a relatively inexpensive device. In addition, an ink jet printing method for dyeing (printing) cloth or the like by an ink jet recording method is being studied. Conventionally, screen printing, roller printing, etc. have been used as printing methods for fabrics (woven fabrics and non-woven fabrics), but inkjet printing methods are applied from the viewpoint of high-variety, low-volume productivity and immediate printing. is advantageous and further development is required.

Pigment printing inks are excellent in color development because the inks are fixed in the vicinity of the surface of the fabric, but on the other hand, there is a problem that they tend to be inferior in fastness to rubbing. Therefore, in order to improve fixability and fastness to rubbing, attempts have been made to incorporate resins into textile inks. For example, in Patent Document 1, for the purpose of improving the adherence of the pigment to the printing object while ensuring the printing characteristics of the ink for inkjet printing, a predetermined pigment, an aqueous dispersion medium, and a pigment Disclosed is a water-based pigment ink composition for inkjet printing comprising four essential components of emulsion particles mainly composed of a dispersant and a polyurethane resin.

JP-A-2003-96342

However, in Patent Document 1, regarding an inkjet recording apparatus having an ink channel having at least a constituent member containing a silicone elastomer or a thermoplastic elastomer, when the inkjet ink composition contains resin particles, deposits are formed in the ink channel. However, there is no mention of problems related to the likelihood of occurrence of

In addition, although it is partially described that the occurrence of problems such as ink ejection failure can be suppressed by setting the average particle diameter of the emulsion resin contained in the inkjet ink composition within a predetermined range, ejection failure In order to prevent this, the physical properties of the resin particles other than the average particle size and the adjustment of other components have not been studied, and the suppression of deposits due to the ink composition in the ink jet recording apparatus having the ink flow path described above has not been sufficiently achieved. It cannot be said that there is.

The inkjet ink composition of the present invention is an inkjet ink composition for use in an inkjet recording apparatus having an ink channel having at least a constituent member containing a silicone elastomer or a thermoplastic elastomer, comprising a pigment, resin particles, and a glycol-based solvent. , a metal hydroxide, an amine compound, and water, the resin particles include a urethane resin having a polycarbonate skeleton, the 100% modulus of the resin particles is 5.0 MPa or more, and the resin The content of the particles is 3.0% by mass or more relative to the total amount of the inkjet ink composition, the normal boiling point of the glycol-based solvent is 250° C. or higher, and the content of the glycol-based solvent is 10 to 30% by mass relative to the total amount of the inkjet ink composition, the content of the metal hydroxide is 0.01% by mass or more relative to the total amount of the inkjet ink composition, and the amine The content of the compound is 0.1% by mass or more with respect to the total amount of the inkjet ink composition, and the total amount of the content of the metal hydroxide and the content of the amine compound is the total amount of the inkjet ink composition. 0.2 to 1.5% by mass with respect to the total amount of the ink composition, and the mass ratio of the content of the glycol-based solvent to the content of the metal hydroxide is 120 to 800. It is a thing.

Further, the recording method of the present invention is a recording method using an inkjet recording apparatus provided with an ink flow path containing at least a constituent member containing a silicone elastomer or a thermoplastic elastomer, wherein the inkjet ink composition passes through the ink flow path. A recording method, comprising: a liquid feeding step of feeding liquid to an inkjet head; and an ink applying step of ejecting the inkjet ink composition from the inkjet head and depositing it on a recording medium.

1 is a schematic diagram of a recording apparatus that can be used in this embodiment; FIG. 1 is a schematic diagram of a self-sealing valve that can be used in this embodiment; FIG.

Hereinafter, embodiments of the present invention (hereinafter referred to as "present embodiments") will be described in detail with reference to the drawings as necessary, but the present invention is not limited thereto and the gist thereof. Various modifications are possible without departing from the above. In the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. In addition, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the illustrated ratios.

1. Inkjet ink composition The inkjet ink composition of the present embodiment (hereinafter also simply referred to as "ink composition") is an ink having at least a constituent member (hereinafter also simply referred to as "member") containing a silicone elastomer or a thermoplastic elastomer. An inkjet ink composition for use in an inkjet recording apparatus having a flow path, comprising a pigment, resin particles, a glycol-based solvent, a metal hydroxide, an amine compound, and water, wherein the resin particles A urethane resin having a polycarbonate skeleton is included, the 100% modulus of the resin particles is 5.0 MPa or more, and the content of the resin particles is 3.0% by mass or more relative to the total amount of the inkjet ink composition. wherein the glycol-based solvent has a normal boiling point of 250° C. or higher, the content of the glycol-based solvent is 10 to 30% by mass with respect to the total amount of the inkjet ink composition, and the metal hydroxide is 0.01% by mass or more based on the total amount of the inkjet ink composition, and the content of the amine compound is 0.1% by mass or more based on the total amount of the inkjet ink composition. and the total amount of the content of the metal hydroxide and the content of the amine compound is 0.2 to 1.5% by mass with respect to the total amount of the inkjet ink composition, and the metal hydroxide An inkjet ink composition, wherein the content of the glycol-based solvent has a mass ratio of 120 to 800 or less to the content of the substance, and may contain a surfactant and other components as necessary.

Conventionally, pigment textile inks are excellent in color developability because the ink is fixed in the vicinity of the surface of the fabric, but on the other hand, there is a problem that the fastness to rubbing tends to be inferior. Therefore, it is conceivable to incorporate resin particles into the textile ink for the purpose of improving fixability and fastness to rubbing.

However, when the ink composition contains resin particles, particularly when the ink composition is used in an inkjet recording apparatus having an ink flow path including a component containing a silicone elastomer or a thermoplastic elastomer, the ink flow path is It has been found that deposits form on the constituent members.

On the other hand, in the present embodiment, by using resin particles containing a urethane resin having a polycarbonate skeleton and having a relatively high 100% modulus, the rubbing fastness is improved and deposits in the ink flow path are removed. suppress the occurrence of The relationship between the urethane resin and the deposits is not particularly limited, but since the urethane resin having a polycarbonate skeleton is excellent in solvent resistance and oil resistance, it can be used as a solvent in the ink composition and as a member constituting the ink flow path. It is thought that this is because it is difficult to aggregate and generate deposits due to the influence of the plasticizer and oil contained in the resin. The relationship between the 100% modulus and deposits is not particularly limited, but it is believed that the lower the 100% modulus, the softer the deposits that tend to stick. However, the mechanism by which a urethane resin having a polycarbonate skeleton and a relatively high 100% modulus suppresses the formation of deposits is not limited to the above.

On the other hand, it has been found that the urethane resin having a polycarbonate skeleton as described above tends to agglomerate when dried, tends to clog nozzles, and deteriorates the cleanability of the nozzle surface. Therefore, in this embodiment, by using a glycol-based solvent, a metal hydroxide, and an amine compound together, drying of the ink is suppressed and dispersion stability of the urethane resin particles is improved.

Therefore, in the present embodiment, by using predetermined resin particles, the rubbing fastness is improved, the generation of deposits on the member is suppressed, and further, the glycol-based solvent, the metal hydroxide, and the amine compound are mixed in a predetermined manner. By containing it in a proportion, the cleanability of the nozzle surface can be improved.

The ink composition will be described in detail below.

1.1. Pigment As the pigment, both inorganic pigments and organic pigments can be used. Pigments may be used singly or in combination of two or more.

As inorganic pigments, furnace black, lamp black, acetylene black, carbon black (CI (Color Index Generic Name) pigment black 7) such as channel black, iron oxide, and titanium oxide can be used.

Organic pigments include azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, and the like. polycyclic pigments, dye chelates (e.g. basic dye chelates, acid dye chelates, etc.), dye lakes (basic dye lakes, acid dye lakes), nitro pigments, nitroso pigments, aniline black, daylight Fluorescent pigments may be mentioned.

The pigment is dispersed in water using a dispersant, or as a pigment dispersion obtained by dispersing in water, or as a self-dispersing surface-treated pigment in which a hydrophilic group is introduced to the surface of the pigment particles using a chemical reaction. It is preferably added as a pigment dispersion obtained by dispersing a pigment coated with a polymer in water.

The content of the pigment is preferably 0.5 to 10% by mass, more preferably 1.0 to 8.0% by mass, and 2.0 to 6.0% by mass as solid content with respect to the total amount of the ink composition. % is more preferred.

1.2. Resin Particles The resin particles contain a urethane resin having a polycarbonate skeleton, and may contain other resins as necessary.

1.2.1. Urethane Resin Having a Polycarbonate Skeleton A urethane resin having a polycarbonate skeleton is a urethane resin containing a carbonate bond in its main chain.

Note that urethane-based resin is a general term for resins having urethane bonds. By containing such a resin, even when the ink composition comes into contact with a constituent member containing a silicone elastomer or a thermoplastic elastomer, it is possible to suppress the formation of deposits on the member. The urethane resin having a polycarbonate skeleton may be a preparation prepared by a known method or a commercially available product.

The resin particles of the present embodiment preferably contain a resin having a crosslinkable group, and more preferably contain a urethane resin having a crosslinkable group. Here, the crosslinkable group may be one that reacts between the crosslinkable groups to form a crosslinked structure, and that reacts between the crosslinkable group and a functional group that is not a crosslinkable group to form a crosslinked structure. can be anything.

Examples of the crosslinkable group include, but are not particularly limited to, a blocked isocyanate group, a silanol group, or these groups protected by a protecting group. Examples of silanol groups include, but are not limited to, triethoxysilyl groups, trimethoxysilyl groups, and tris(2-methoxyethoxy)silyl groups. From the viewpoint of storage stability and cross-linking reaction reactivity, the cross-linkable group is preferably a blocked isocyanate group. The blocked isocyanate may be a preparation prepared by a known method, or a commercially available product. When the resin particles contain such a resin having a crosslinkable group, a crosslinked structure is formed between the resins, which tends to further improve the rubbing fastness.

The 100% modulus of the resin particles is 5.0 MPa or more, more preferably 10 to 35 MPa, still more preferably 15 to 30 MPa. When the 100% modulus of the resin particles is 5.0 MPa or more, the rubbing fastness can be improved, and even when the ink composition comes into contact with the member, the formation of deposits on the member can be suppressed. tend to be able to

The content of the resin particles is 3.0% by mass or more, preferably 5.0 to 15% by mass, more preferably 5.0 to 15% by mass, as a solid content, based on the total amount of the ink composition. 10% by mass. When the content of the resin particles is within such a range, the rubbing fastness can be improved, and the formation of deposits on the member can be suppressed even when the ink composition comes into contact with the member. There is a tendency.

1.2.2. Other resins Other resins include, but are not limited to, acrylic resins, fluorene resins, polyolefin resins, rosin-modified resins, terpene resins, polyester resins, polyamide resins, epoxy resins, and vinyl chloride. and resin particles made of ethylene-vinyl acetate-based resin or the like. These resin particles may be in the form of an emulsion, may be in the form of powder, may be used singly, or may be used in combination of two or more.

1.3. Water-Soluble Organic Solvent The ink composition of the present embodiment contains a glycol-based solvent having a normal boiling point of 250° C. or higher, and may contain other water-soluble organic solvents.

1.3.1. Glycol-Based Solvent The ink composition of the present embodiment contains a glycol-based solvent with a normal boiling point of 250° C. or higher as the glycol-based solvent, and may further include a glycol-based solvent with a normal boiling point of less than 250°C. In addition, in this embodiment, the "glycol-based solvent" includes glycol monoether and glycol diether in addition to glycol.

Examples of such glycol-based solvents include, but are not limited to, diethylene glycol di-n-butyl ether (boiling point 255°C), diethylene glycol monohexyl ether (boiling point 259°C), triethylene glycol (boiling point 276°C), and triethylene glycol. monobutyl ether (boiling point 278°C), tripropylene glycol (boiling point 273°C), tripropylene glycol monobutyl ether (boiling point 271°C), polyethylene glycol monomethyl ether (boiling point 290°C), and glycerin (boiling point 290°C). .

The content of the glycol-based solvent having a normal boiling point of 250° C. or higher is 10 to 30% by mass, preferably 14 to 26% by mass, more preferably 18 to 22% by mass, relative to the total amount of the ink composition. is. When the content of the glycol-based solvent is within such a range, it is possible to suppress the formation of deposits on members even when the ink composition comes into contact with the members, and to keep the ink composition moist. drying can be prevented, and the cleaning property of the nozzle surface tends to be improved.

Further, in the present embodiment, the mass ratio of the content of the glycol-based solvent having a normal boiling point of 250° C. or higher to the content of the metal hydroxide described later is 120 to 800, preferably 150 to 600, More preferably 180-400. When the mass ratio of the content of the glycol-based solvent to the content of the metal hydroxide is within such a range, the formation of deposits on the member is suppressed even when the ink composition comes into contact with the member. In addition, it tends to be possible to improve the cleanability of the nozzle surface.

1.3.2. Other water-soluble organic solvents Other water-soluble organic solvents include, but are not limited to, glycerin; nitrogen-containing solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone; methanol , ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol, etc. alcohols.

1.4. Metal Hydroxide As the metal hydroxide, those having strong alkalinity are preferred. A metal hydroxide may be used individually by 1 type, and may be used in combination of 2 or more type.

As metal hydroxides, preferably alkali metal hydroxides and/or alkaline earth metal hydroxides are included, more preferably alkali metal hydroxides are included, and even more preferably lithium hydroxide, sodium hydroxide , potassium hydroxide. By including such a metal hydroxide in the ink composition, the dispersion stability of the ink composition can be improved, and even when the ink composition comes into contact with the member, deposits on the member can be prevented. In addition to being able to suppress it, there is a tendency that the cleanability of the nozzle surface can be improved.

The content of the metal hydroxide is 0.01% by mass or more, preferably 0.03 to 0.5% by mass, more preferably 0.05 to 0.5% by mass, relative to the total amount of the ink composition. It is 0.2% by mass. When the content of the metal hydroxide is within such a range, it is possible to suppress the formation of deposits on the member even when the ink composition comes into contact with the member, and to improve the cleanability of the nozzle surface. tend to be improved.

1.5. Amine Compound As the amine compound, one having a function as a weakly alkaline pH adjuster is preferable. An amine compound may be used individually by 1 type, and may be used in combination of 2 or more type.

The amine compound preferably comprises an amphiphilic amine compound, more preferably an alkanolamine. Examples of alkanolamine include, but are not particularly limited to, ethanolamine, propanolamine, tripropanolamine, and triethanolamine. By including such an amine compound in the ink composition, it is possible to suppress the formation of deposits on the member even when the ink composition comes into contact with the member, and to improve the cleanability of the nozzle surface. tends to be possible.

The content of the amine compound is 0.1% by mass or more, preferably 0.2 to 2.0% by mass, more preferably 0.4 to 1.0% by mass, relative to the total amount of the ink composition. It is 0% by mass. When the content of the amine compound is within such a range, it is possible to suppress the formation of deposits on the member even when the ink composition comes into contact with the member, and improve the cleanability of the nozzle surface. tend to be able to

1.6. Surfactant The ink composition of the present embodiment may further contain a surfactant. Surfactants may be used singly or in combination of two or more.

Examples of surfactants include, but are not particularly limited to, silicone-based surfactants, acetylene glycol-based surfactants, and fluorine-based surfactants. Among these, silicone-based surfactants with high surface activity and low foaming properties are preferred.

Examples of silicone-based surfactants include polysiloxane-based compounds and polyether-modified organosiloxanes.

The acetylene glycol surfactant is not particularly limited, but examples include 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5- selected from alkylene oxide adducts of decyne-4,7-diol and alkylene oxide adducts of 2,4-dimethyl-5-decyn-4-ol and 2,4-dimethyl-5-decyn-4-ol One or more is preferred.

Examples of fluorine-based surfactants include, but are not limited to, perfluoroalkylsulfonates, perfluoroalkylcarboxylates, perfluoroalkyl phosphates, perfluoroalkylethylene oxide adducts, perfluoroalkylbetaines, perfluoroalkyl Fluoroalkylamine oxide compounds are mentioned.

The content of the surfactant is preferably 0.1 to 2.0% by mass, more preferably 0.2 to 1.5% by mass, and still more preferably 0% by mass, relative to the total amount of the ink composition. .3 to 1.0% by mass.

1.7. Water The content of water in the ink composition of the present embodiment is preferably 55 to 80% by mass, more preferably 60 to 80% by mass, and still more preferably 65 to 80% by mass, relative to the total amount of the ink composition. 75% by mass.

1.8. Other Components The ink composition of the present embodiment may contain one or more known components that can be used in addition to the components described above. Examples of such known ingredients include, but are not limited to, solubilizers, viscosity modifiers, pH modifiers, antioxidants, preservatives, antifungal agents, corrosion inhibitors, and metal ions that affect dispersion. and other additives such as chelating agents and solvents other than those mentioned above.

2. Inkjet Recording Apparatus The inkjet recording apparatus of the present embodiment includes an ink flow path having at least a constituent member containing a silicone elastomer or a thermoplastic elastomer, and if necessary, an inkjet head for ejecting an ink composition, and an ink composition. and an ink containing body for containing.

Also, the ink flow path has at least a constituent member containing a silicone elastomer or a thermoplastic elastomer, and preferably comprises a constituent member containing a thermoplastic elastomer. When using such an ink flow path, the present invention is particularly useful because the generation of deposits is particularly remarkable.

In this embodiment, the term “ink channel” refers to a channel for circulating ink in an inkjet recording apparatus. Examples of such an ink flow path include an ink supply path for supplying ink from an ink storage container that stores ink to the ink jet recording head, and a flow path for circulating ink to the nozzle openings in the ink jet recording head. of the flow path. In addition, self-sealing valves, inkjet heads, and the like are also included as constituent members of the ink flow path. In particular, since the self-sealing valve deforms every time the ink composition is ejected from the inkjet head, the formation of deposits causes ejection failure. Therefore, the present invention is particularly useful.

FIG. 1 shows a serial-type inkjet recording apparatus as an inkjet apparatus that is an example of the present embodiment. As shown in FIG. 1, an inkjet recording apparatus 10 includes an apparatus frame 11, a recording unit 12 having an inkjet head 13, and a conveying unit (in this embodiment, shown in the drawing) that feeds a recording medium P so as to pass through the recording unit 12. not), and In addition, the inkjet recording apparatus 10 has the above-described ink supply unit 16 (functional liquid supply unit), an ink supply unit 15 that supplies ink to the inkjet head 13, a cleaning unit 17 that cleans the inkjet head 13, and a control unit 18 for integrally controlling these constituent devices. In the following, an explanation will be given using an X-Y-Z orthogonal coordinate system. That is, the feeding direction of the recording medium P is defined as the X-axis direction, the direction orthogonal to the X-axis direction in the plane of the recording medium P is defined as the Y-axis direction, and the direction orthogonal to the X-axis direction and the Y-axis direction is defined as the Z-axis direction. .

FIG. 1 shows a serial printing apparatus as an example of the ink jet printing apparatus of the present embodiment, but the present embodiment is not limited to the above serial printing apparatus, and may be a line printing apparatus. may A line-type recording apparatus is a recording apparatus that uses a line head, which is an inkjet head having a length equal to or longer than the recording width of the recording medium, to perform recording on the recording medium in one scan.

Although the details of the conveying unit 14 are not shown, the recording medium P is conveyed in the X-axis direction from the top to the bottom in FIG. 1 by the conveying unit 14 during recording. In this case, recording on the recording medium P is performed by main scanning of the inkjet head 13 by the printing unit 12 and sub-scanning (line feed), which is intermittent feeding of the recording medium P by the conveying unit 14 .

The printing unit 12 includes an inkjet head 13 that ejects four droplets corresponding to each of Y, M, C, and B (black) inks, a carriage 23 on which the inkjet head 13 is mounted, and a carriage 23 . A head moving mechanism 24 for reciprocating the inkjet head 13 in the Y-axis direction, and a platen platen 25 facing the inkjet head 13 with a predetermined gap and constituting a part of the feeding path of the recording medium P. and have.

The head moving mechanism 24 includes a carriage motor 26 as a power source, a drive pulley 27a and a driven pulley 27b driven by the carriage motor 26, a timing belt 28 stretched between the drive pulley 27a and the driven pulley 27b, and the carriage 23. and a guide rod 29 slidably supporting the in the Y-axis direction. The carriage 23 is fixed to a part of the timing belt 28 , and the four droplet ejection heads 13 are guided by the guide rods 29 by running the timing belt 28 forward and backward via the carriage motor 26 . It reciprocates in the Y-axis direction. Printing is performed by appropriately driving the inkjet head 13 that ejects four droplets in synchronization with this reciprocating movement (main scanning).

The ink supply unit 15 has four cartridge-type ink tanks 31 that store Y, M, C, and B inks, and four ink tanks 31 that are connected to the inkjet head 13 that ejects four droplets. It includes four ink tubes 32 and four ink pumps (not shown in this embodiment) that are interposed in each ink tube 32 and feed the ink in each ink tank 31 to the inkjet head 13 .

Here, with reference to FIG. 2, the structure around the ink supply unit 16 will be described in detail. As described above, the ink supply unit 16 is provided for each inkjet head 13 for each ink color. Each ink supply unit 16 has a self-sealing valve 36 that adjusts the pressure of ink and supplies it to the inkjet head 13, and a valve driving device 37 that forcibly opens the self-sealing valve 36 (valve opening). are doing. The self-sealing valve 36 is provided so that the outflow side is directly connected to the inkjet head 13 , and the valve driving device 37 is arranged so as to face the self-sealing valve 36 . The downstream end of the ink tube 32 is connected to the inflow side of the self-sealing valve 36 .

2.1. Self-sealing valve As shown in FIG. 2, the self-sealing valve 36 is a so-called pressure regulating valve that adjusts the ink supply pressure based on the atmospheric pressure. The self-sealing valve 36 has a housing 61 made of resin, a primary liquid chamber 62 having an inlet 63 defined in the housing 61, and an outlet 65 defined in the housing 61. A secondary liquid chamber 64, a communication passage 66 that communicates the primary liquid chamber 62 and the secondary liquid chamber 64, and a valve body 67 that opens and closes the communication passage 66 from the primary liquid chamber 62 side. The ink tube 32 is connected to the inflow port 63 , and the inkjet head 13 is directly connected to the outflow port 65 .

The self-sealing valve 36 is provided on one wall surface (opening of the housing 61) of the secondary liquid chamber 64 and liquid-tightly separates the secondary liquid chamber 64 from the atmosphere (outside). A pressure receiving member 71 that reacts with the pressure difference between the pressure of 64 and the atmospheric pressure, and an operating member 72 that transmits the response of the pressure receiving member 71 to the valve body 67 to open and close the valve body 67 . The valve body 67 and the operating member 72 are integrally formed, and the operating member 72 passes through the communication passage 66 and extends to the vicinity of the pressure receiving member 71 . On the other hand, a valve seat 73 is formed by an opening edge of a communication channel 66 that opens to the primary liquid chamber 62, and a seal ring 74 provided on a valve element 67 is separated from and contacts the valve seat 73, thereby opening the communication channel. 66 opens and closes (opens and closes).

The primary liquid chamber 62 also incorporates a valve body spring 75 that weakly biases the valve body 67 in the closing (valve closing) direction. The closing operation of the valve body 67 and the fine adjustment of the adjustment pressure are performed. The pressure-receiving member 71 has a circular membrane 77 that partitions the opening of the housing 61, and a circular pressure-receiving plate portion 78 concentrically adhered to the outside of the membrane 77 (the side opposite to the secondary liquid chamber 64). are doing. The pressure receiving plate portion 78 is formed to have a diameter sufficiently smaller than that of the film body 77 , and the pressure receiving member 71 seen from the outside consists of the pressure receiving plate portion 78 positioned in the central portion and the film surrounding the pressure receiving plate portion 78 . and a pressure-receiving membrane portion 77 a that is a part of the body 77 .

The pressure-receiving plate portion 78 is made of a resin plate or the like having appropriate rigidity, and the pressure-receiving film portion 77a (membrane body 77) is made of a resin film or the like having appropriate flexibility. Therefore, the pressure-receiving member 71, which responds to the pressure difference between the pressure in the secondary liquid chamber 64 and the atmospheric pressure, responds as a whole mainly due to the response of the pressure-receiving film portion 77a. A front end portion of the operating member 72 is opposed to the central portion of the pressure receiving plate portion 78 with the membrane body 77 interposed therebetween. The valve body 67 opens and closes while the reaction of the valve body 71 and the biasing force of the valve body spring 75 are balanced. The pressure receiving member 71 may be composed of a hard portion corresponding to the pressure receiving plate portion 78 and a soft portion corresponding to the pressure receiving film portion 77a.

In the self-sealing valve 36 configured as described above, when the pressure in the secondary liquid chamber 64 decreases due to the ejection of ink (mainly printing) from the inkjet head 13, the pressure receiving member 71 closes to the secondary liquid chamber 64 due to the atmospheric pressure. Concave deformation to the side. When the pressure-receiving member 71 is deformed, the pressure-receiving plate portion 78 presses the operating member 72 to open the valve body 67 against the valve body spring 75 . As a result, ink flows from the primary liquid chamber 62 into the secondary liquid chamber 64 via the communication channel 66 . As the inflow of ink continues and the pressure in the secondary liquid chamber 64 increases, the pressure receiving member 71 is deformed to project outward against the atmospheric pressure. When the pressure-receiving member 71 deforms outward, the valve body spring 75 moves the valve body 67 toward the secondary liquid chamber 64 to close the communication channel 66 (open/close valve).

Thus, the self-sealing valve 36 opens and closes the communication channel 66 based on the atmospheric pressure, and supplies ink to the inkjet head 13 at a constant pressure. Therefore, the amount of ink droplets ejected from the inkjet head 13 is stabilized.

3. Recording Method The inkjet recording method of the present embodiment is a recording method using an inkjet recording apparatus provided with an ink flow path containing at least a constituent member containing a silicone elastomer or a thermoplastic elastomer. and an ink application step of ejecting an inkjet ink composition from an inkjet head and attaching it to a recording medium.

3.1. Liquid Feeding Process The liquid feeding process is a process of feeding the ink composition to the inkjet head through the ink flow path. More specifically, in the liquid feeding step, the ink composition stored in the ink container may be liquid fed to the nozzle of the inkjet head through a self-sealing valve or the like. At this time, the self-sealing valve opens and closes due to pressure changes caused by ejection of ink from the inkjet head, and ink can be stably supplied to the nozzles at a constant pressure.

3.2. Ink Attachment Step In the ink attachment step, ink is ejected from an inkjet head and attached to a recording medium. More specifically, the pressure generating means provided in the inkjet head is driven to eject the ink filled in the pressure generating chamber of the inkjet head from the nozzles.

The ink jet head used in the ink application process includes a line head that performs recording by a line method and a serial head that performs recording by a serial method.

In the line method using a line head, for example, an inkjet head having a width equal to or larger than the recording width of the recording medium is fixed to the recording apparatus. Then, an image is recorded on the recording medium by moving the recording medium along the sub-scanning direction (conveying direction of the recording medium) and ejecting ink droplets from the nozzles of the inkjet head in conjunction with this movement.

In a serial method using a serial head, for example, an inkjet head is mounted on a carriage that can move in the width direction of a recording medium. An image is recorded on the recording medium by moving the carriage along the main scanning direction (the width direction of the recording medium) and ejecting ink droplets from the nozzles of the inkjet head in conjunction with this movement.

3.3. Recording Medium The recording medium used in the present embodiment is not particularly limited, and examples thereof include fabric (hydrophobic fiber fabric, etc.), resin (plastic) film, paper, glass, metal, and ceramics. Moreover, as the recording medium, in addition to the sheet-like shape, for example, a material having a three-dimensional shape such as a spherical shape or a rectangular parallelepiped shape may be used.

When the recording medium is a fabric, the fibers constituting the fabric are not particularly limited. Examples include natural fibers such as cotton, silk, and wool; polyester fibers, nylon fibers, triacetate fibers, diacetate fibers, polyamide fibers, and the like. artificial fibers; and blended products using two or more of these fibers. A blended product of these with regenerated fibers such as rayon or the above natural fibers may also be used.

Further, when the recording medium is a resin (plastic) film, the resin (plastic) film is not particularly limited, but examples include polyester film, polyurethane film, polycarbonate film, polyphenylene sulfide film, polyimide film, polyamideimide film, and the like. is mentioned.

Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is by no means limited by the following examples.

1. Preparation of Ink Composition Each component was put into a mixing tank so as to have the composition shown in Tables 1 and 2, mixed and stirred, and filtered through a 5 μm membrane filter to obtain an ink composition of each example. rice field. In addition, the numerical value of each component shown in each example in the table represents % by mass unless otherwise specified. The weight percentages of the pigments and resin particles in Tables 1 and 2 represent the respective solid content concentrations.

The materials shown in Tables 1 and 2 are as follows.
<Pigment>
・BONJET BLACK CW-1 (pigment solid content 20%, manufactured by Orient Chemical Industry Co., Ltd., carbon black-based water dispersion)
<Resin particles>
・Takelac WS5100 (manufactured by Mitsui Chemicals, polycarbonate-based urethane-based resin, 100% modulus: 28 MPa)
・Takelac W6110 (manufactured by Mitsui Chemicals, polycarbonate-based urethane-based resin, 100% modulus: 2.0 MPa)
・ Movinyl 966A (manufactured by Japan Coating Resin Co., Ltd., styrene-acrylic resin)
<Glycol-based solvent>
・Glycerin (normal boiling point: 290°C)
・Ethylene glycol (normal boiling point: 198°C)
<Amine compound>
・Propanolamine <metal hydroxide>
・Sodium hydroxide <surfactant>
· BYK348 (manufactured by BYK-Chemie Japan, polyether-modified siloxane surfactant)

2. Production of Recorded Matter First, a white cotton broadcloth was prepared as a fabric used for production of a recorded matter. After that, the cotton broad cloth was padded with a pretreatment agent consisting of 6.7 parts of Unisense 104L (manufactured by Senka, water-soluble cationic polymer) and 93.3 parts of water at a squeeze rate of 70%, and then dried at 120°C. The pretreated fabric was obtained by drying for 5 minutes.

Subsequently, the ink composition was applied to the pretreated fabric by an inkjet method using an inkjet printer (product name “SC-F2000” manufactured by Seiko Epson Corporation) to form an image. In the above image forming process, an image was formed by setting the resolution to 1440×720 dpi, setting the printing range to A4 size, and performing solid printing with a coating amount of 20 g/m ² of the color ink composition. Then, using a high-temperature steamer (manufactured by Tsujii Senki Kogyo Co., Ltd., "HT-3-550 model"), the pretreated fabric was dried at 160°C for 5 minutes to produce a printed material in which an image was formed. . Here, solid printing means landing ink droplets (dots) on all the pixels in the minimum recording unit area defined by the recording resolution.

3. Evaluation method 3.1. Evaluation of deposits on members As a simple evaluation of deposits on MNCS (thermoplastic elastomer manufactured by Bridgestone) members in an inkjet printer, the MNCS member with a notch and the ink composition were placed in an aluminum bag and sealed. and left at about 40° C. for 15 days. Thereafter, 10 ml of the ink composition was filtered through a metal mesh filter (pore size 10 μm), and the number of aggregates captured by the metal mesh filter was counted per 1 mm square and evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: The number of aggregates is less than 10.
B: The number of aggregates is 10 or more and less than 30.
C: The number of aggregates is 30 or more.

3.2. Cleanability of Nozzle Surface The ink composition of each example and comparative example was filled in all rows of the inkjet head of an inkjet printer ("SC-F2000" manufactured by Seiko Epson Corporation), and it was confirmed that all rows ejected normally. . After that, the print head was moved from the standby position and stopped in the printing area, and left in an environment of 40° C. and 20% RH for 3 days. Thereafter, the print head was returned to the standby position and wiped off using a rubber wiper. The number of cleanings required until ejection from the inkjet head was recovered was counted and evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: All nozzles recovered after cleaning three times or less.
B: All nozzles recovered after cleaning 4 times or more and 10 times or less.
C: No recovery even after cleaning 11 times or more.

3.3. Evaluation of Storage Stability Each ink composition was placed in a 50 cc glass sample bottle, sealed, placed in a 50° C. constant temperature bath, and allowed to stand in a 50° C. environment for 14 days. Then, the viscosity was measured after confirming that the temperature had sufficiently returned to room temperature. The viscosity was determined by reading the viscosity at a shear rate of 200 after adjusting the temperature of the ink composition to 25° C. using a viscoelasticity tester MCR-300 (product name) manufactured by Pysica. Then, the viscosity change rate A after 14 days from the initial viscosity was calculated and evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: Viscosity change rate A is within ±5%.
B: Viscosity change rate A is ±5% or more and less than 10%.
C: Viscosity change rate A is ±10% or more.

3.4. Evaluation of fastness to rubbing Each of the ink compositions shown in Tables 1 and 2 was used to form an image on a fabric by the method described above to obtain a recorded matter. A color fastness test to rubbing was performed using a type I (Crockmeter) tester according to the method specified in ISO-105 X12 for the recorded matter obtained with the ink composition of each example. Dry friction was tested according to the dry test specified in ISO-105 X12, and evaluated according to the following evaluation criteria using a stain gray scale. The evaluation criteria were as follows.
〔Evaluation criteria〕
A: Contamination gray scale is grade 3 or higher.
B: Contamination gray scale is grade 2 or more and less than grade 3.
C: Contamination gray scale is grade 1 or more and less than grade 2.

4. Evaluation Results As shown in Tables 1 and 2, according to a comparison between Examples 1 to 8 and Comparative Examples 1 to 10, the ink composition according to the present embodiment does not satisfy the constituent requirements of the ink composition. It was found to be superior to the ink compositions of Examples 1 to 10 in terms of fastness to rubbing, deposits on members, and cleanability of the nozzle surface.

DESCRIPTION OF SYMBOLS 10... Ink jet recording device 12... Printing part 13... Ink jet head 13a... Nozzle surface 14... Conveying part 15... Ink supply part 16... Ink supply unit 17... Cleaning part 18... Control part 24... Head moving mechanism 31 Ink tank 32 Ink tube 35 Ink pressure unit 36 Self-sealing valve 37 Valve driving device 41 Cap unit 42 Wiping unit 61 Housing 62 Primary liquid chamber 63 Inlet 64 Secondary liquid chamber 65 Outlet 66 Communicating flow path 67 Valve body 71 Pressure receiving member 72 Actuating member 75 Valve body spring 77 Membrane body 77a Pressure-receiving membrane portion 78 Pressure-receiving plate portion 80 Pressing driving portion 81 Pressing member 82 Plate pressing portion 83 Membrane pressing portion 84 Advance/retreat mechanism 86 DC motor 87 ... lead screw mechanism, P ... recording medium.

Claims (9)

An inkjet ink composition for use in an inkjet recording apparatus having an ink channel having at least a constituent member containing a silicone elastomer or a thermoplastic elastomer,
including a pigment, resin particles, a glycol-based solvent, a metal hydroxide, an amine compound, and water,
The resin particles contain a urethane resin having a polycarbonate skeleton,
100% modulus of the resin particles is 5.0 MPa or more,
The content of the resin particles is 3.0% by mass or more with respect to the total amount of the inkjet ink composition,
The normal boiling point of the glycol-based solvent is 250° C. or higher,
The content of the glycol-based solvent is 10 to 30% by mass with respect to the total amount of the inkjet ink composition,
The content of the metal hydroxide is 0.01% by mass or more with respect to the total amount of the inkjet ink composition,
The content of the amine compound is 0.1% by mass or more with respect to the total amount of the inkjet ink composition,
The total amount of the content of the metal hydroxide and the content of the amine compound is 0.2 to 1.5% by mass with respect to the total amount of the inkjet ink composition,
The mass ratio of the content of the glycol-based solvent to the content of the metal hydroxide is 120 to 800,
Inkjet ink composition. The resin particles contain the urethane resin having a crosslinkable group,
The inkjet ink composition of claim 1. wherein the crosslinkable group comprises a blocked isocyanate group;
3. The inkjet ink composition of claim 2. The content of the resin particles is 5.0 to 10% by mass with respect to the total amount of the inkjet ink composition.
The inkjet ink composition according to any one of claims 1-3. including a self-sealing valve as the component,
The inkjet ink composition according to any one of claims 1-4. wherein the component comprises the thermoplastic elastomer;
The inkjet ink composition according to any one of claims 1-5. wherein the amine compound comprises an alkanolamine;
The inkjet ink composition according to any one of claims 1-6. wherein the metal hydroxide comprises an alkali metal hydroxide and/or an alkaline earth metal hydroxide;
The inkjet ink composition according to any one of claims 1-7. A recording method using an ink jet recording apparatus having an ink flow path including at least a constituent member containing a silicone elastomer or a thermoplastic elastomer,
a liquid feeding step of feeding the inkjet ink composition according to any one of claims 1 to 8 to an inkjet head through an ink channel;
an ink applying step of ejecting the inkjet ink composition from the inkjet head and attaching it to a recording medium;
Recording method.