Image recording method and image recording system

Abstract

To provide an image recording method and an image recording system capable of achieving high dye ability to a fabric including natural fibers and suppressing yellow discoloration in heating and color change under a high humidity environment.SOLUTION: There is provided an image recording method for dyeing a fabric including natural fibers by a sublimation transfer method, comprising: a step of applying pretreatment liquid to the fabric; a step of drying the fabric; a step of applying a sublimation ink to a transfer medium; and a step of transferring the sublimation ink from the transfer medium to the fabric. The pretreatment liquid includes as a solvent, an organic solvent including nitrogen or sulfur, an application amount of the organic solvent immediately after the step of applying the pretreatment liquid, is in a range of 10-150 mass% with respect to mass of the whole fabric. In the step of transferring, a residual amount of the organic solvent immediately before the sublimation ink transfer with respect to the fabric is in a range of 3-40 mass% with respect to the mass of the whole fabric.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image recording method and an image recording system. More specifically, it relates to an image recording method and an image recording system that have high dyeing properties on fabrics containing natural fibers and can suppress yellowing during heating and color change in a high-humidity environment.

Background Art

[0002] Conventionally, a printing method (sublimation transfer method) is known in which ink containing a sublimation dye is applied to a transfer medium, and then the ink is transferred from the transfer medium to dye the fabric. In the above printing method, since sublimation dyes generally exhibit hydrophobicity, they tend to adhere to polyester fabrics that also exhibit hydrophobicity, and appropriate printing can be performed. On the other hand, for fabrics containing fibers such as natural fibers and synthetic cellulose fibers that exhibit hydrophilicity, due to the polarity difference between the sublimation dye and the fabric, the sublimation dye is difficult to adhere, and printing tends to be insufficient.

[0003] To address the above problems, as in Patent Documents 1 and 2, before transferring a printing ink containing a sublimation dye by the sublimation transfer method, a swelling agent (such as polyhydric alcohols) is preliminarily impregnated into the fabric to swell the fabric, thereby widening the gaps between the fibers and making it easier for the sublimation dye to enter the interior of the fibers.

[0004] However, for fabrics containing fibers such as natural fibers and synthetic cellulose fibers that exhibit hydrophilicity, simply widening the gaps between the fibers by swelling the fabric as described above and making it easier for the sublimation dye to enter the interior of the fibers results in insufficient dyeing concentration. Also, if the amount of the swelling agent impregnated into the fabric is too large, the white portion of the transferred image may turn yellow, and the portion where the sublimation ink is printed may change color when the transferred image is left in a high-humidity environment for a long time. There was room for improvement in the technique of preliminarily impregnating a swelling agent (such as polyhydric alcohols) into the fabric.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of the above problems and situations, and the problem to be solved is to provide an image recording method and an image recording system that have high dyeability for fabrics containing natural fibers and can suppress yellowing during heating and discoloration in a high-humidity environment.

Means for Solving the Problems

[0007] As a result of studying the causes of the above problems in order to solve the above problems, the inventor of the present invention found that in an image recording method for dyeing a fabric by a sublimation transfer method, before transferring sublimation ink to the fabric, an organic solvent containing nitrogen or sulfur is applied in advance to moderately swell the fabric, and by reducing the amount of the organic solvent for the fabric to a certain amount immediately before the sublimation ink transfer, the above problems can be solved, and thus the present invention was achieved. That is, the above problems according to the present invention are solved by the following means.

[0008] 1. An image recording method for dyeing a fabric containing natural fibers using a sublimation transfer method, comprising the steps of: applying a pretreatment solution to the fabric; drying the fabric; applying sublimation ink to a transfer medium; and transferring the sublimation ink from the transfer medium to the fabric, wherein the pretreatment solution contains an organic solvent containing nitrogen or sulfur as a solvent, the amount of the organic solvent applied immediately after the application of the pretreatment solution is within the range of 10 to 150% by mass of the total mass of the fabric, and the amount of the organic solvent remaining immediately before the transfer of the sublimation ink to the fabric in the transfer step is within the range of 3 to 40% by mass of the total mass of the fabric.

[0009] 2. The image recording method according to paragraph 1, characterized in that the temperature during the drying process of the fabric is lower than the boiling point of the organic solvent.

[0010] 3. Dry the fabric. warm The image recording method according to paragraph 1 or 2, characterized in that the temperature is lower than the heating temperature during transfer.

[0011] 4. The image recording method according to paragraph 3, characterized in that the pretreatment solution contains an aromatic heterocyclic compound.

[0012] 5. The image recording method according to paragraph 3, characterized in that the pretreatment solution is applied by an inkjet method.

[0013] 6. An image recording system for dyeing a fabric containing natural fibers using a sublimation transfer method, comprising: means for applying a pretreatment solution to the fabric; means for drying the fabric; means for applying sublimation ink to a transfer medium; and means for transferring the sublimation ink from the transfer medium to the fabric. and, The pretreatment solution contains an organic solvent containing nitrogen or sulfur as a solvent, and the amount of the organic solvent applied immediately after the means for applying the pretreatment solution is within the range of 10 to 150% by mass of the total mass of the fabric. Control to be soFurthermore, the amount of the organic solvent remaining in the transfer means immediately before the transfer of the sublimation ink to the fabric is within the range of 3 to 40% by mass of the total mass of the fabric. It comprises a control means for controlling it to be so as to Image recording system. [Effects of the Invention]

[0014] The present invention provides an image recording method and an image recording system that offer high dyeability for fabrics containing natural fibers and can suppress yellowing during heating and discoloration in high-humidity environments. Although the mechanism by which the effects of this invention manifest or the mechanism of action are not yet clear, we speculate as follows.

[0015] The present invention relates to an image recording method for dyeing using a sublimation transfer method, in which a specific amount of a pretreatment solution containing an organic solvent containing nitrogen or sulfur is applied to a fabric containing natural fibers, the fabric is swollen and then dried to reduce the content of the organic solvent in the pretreatment solution, and then a sublimation dye is transferred to record an image.

[0016] As mentioned above, in conventional technology, a swelling agent (polyhydric alcohol) was impregnated into the fabric beforehand, causing it to swell and widening the gaps between the fibers, which made it easier for the sublimation dye to penetrate into the fibers. However, the dyeing density of the recorded image was insufficient, and if too much of the swelling agent was impregnated into the fabric, the white areas of the transferred image may turn yellow. Furthermore, if the transferred image was left in a high-humidity environment for a long time, the areas where the sublimation ink was printed may discolor.

[0017] The image recording method of the present invention uses a pretreatment solution that contains an organic solvent containing nitrogen or sulfur as a solvent for the sublimation dye. Because it also functions as a swelling agent, it is easier to capture the sublimation dye inside the fibers of the fabric compared to transfer images using conventional swelling agents (polyhydric alcohols), resulting in a higher dyeing density.

[0018] Furthermore, by swelling the fabric with a swelling agent to widen the gaps between fibers and make it easier for the sublimation dye to penetrate the fibers, and then drying the fabric, the amount of the organic solvent in the pretreatment solution is reduced, thereby controlling the amount of the swelling agent to a constant level. This makes it possible to suppress yellowing of the white areas of the transfer image and discoloration of the sublimation ink in a high-humidity environment caused by using too much swelling agent. [Brief explanation of the drawing]

[0019] [Figure 1] A schematic diagram showing an example of the image recording system of the present invention. [Figure 2] Block diagram showing the internal configuration of the pretreatment liquid application device. [Modes for carrying out the invention]

[0020] The present invention relates to an image recording method for dyeing a fabric containing natural fibers using a sublimation transfer method, comprising the steps of: applying a pretreatment solution to the fabric; drying the fabric; applying sublimation ink to a transfer medium; and transferring the sublimation ink from the transfer medium to the fabric, wherein the pretreatment solution contains an organic solvent containing nitrogen or sulfur as a solvent, the amount of the organic solvent applied immediately after the application of the pretreatment solution is in the range of 10 to 150% by mass relative to the total mass of the fabric, and the amount of the organic solvent remaining immediately before the transfer of the sublimation ink to the fabric in the transfer step is in the range of 3 to 40% by mass relative to the total mass of the fabric. This feature is a technical feature common to or corresponding to each of the embodiments (appearances) described below.

[0021] In embodiments of the present invention, it is preferable that the temperature during the drying process of the fabric is lower than the boiling point of the organic solvent, from the viewpoint of making it easier to retain the organic solvent within an optimal amount inside the fabric.

[0022] From the viewpoint of suppressing discoloration of the white areas of the fabric due to heating, it is preferable that the temperature at which the fabric is dried is lower than the heating temperature during the transfer process.

[0023] It is preferable that the aforementioned pretreatment solution contains an aromatic heterocyclic compound, as this facilitates the capture of the dye in the sublimation ink within the fibers of the fabric, thereby increasing the dyeing concentration.

[0024] From the viewpoint of enabling the application of the pretreatment solution by an inkjet method to be carried out continuously with the sublimation ink application process, it is preferable.

[0025] The present invention is suitable for use in an image recording system for dyeing a fabric containing natural fibers by a sublimation transfer method, the system comprising means for applying a pretreatment solution to the fabric, means for drying the fabric, means for applying sublimation ink to a transfer medium, and means for transferring the sublimation ink from the transfer medium to the fabric, wherein the pretreatment solution contains an organic solvent containing nitrogen or sulfur as a solvent, the amount of the organic solvent applied immediately after applying the pretreatment solution is in the range of 10 to 150% by mass of the total mass of the fabric, and the amount of the organic solvent remaining in the transfer means immediately before transferring the sublimation ink to the fabric is in the range of 3 to 40% by mass of the total mass of the fabric.

[0026] The present invention, its components, and embodiments and models for carrying out the present invention will be described in detail below. In this application, "~" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0027] I. Image Recording Method The present invention relates to an image recording method for dyeing a fabric containing natural fibers using a sublimation transfer method, comprising the steps of: applying a pretreatment solution to the fabric; drying the fabric; applying sublimation ink to a transfer medium; and transferring the sublimation ink from the transfer medium to the fabric, wherein the pretreatment solution contains an organic solvent containing nitrogen or sulfur as a solvent, the amount of the organic solvent applied immediately after the application of the pretreatment solution is in the range of 10 to 150% by mass relative to the total mass of the fabric, and the amount of the organic solvent remaining immediately before the transfer of the sublimation ink to the fabric in the transfer step is in the range of 3 to 40% by mass relative to the total mass of the fabric. In this specification, "total mass of the fabric" does not mean the mass of the entire fabric to which the pretreatment solution is to be applied (for example, the entire roll when the fabric is unrolled and the pretreatment solution is to be applied), but rather the mass of the fabric itself per unit area of ​​a portion of the fabric to which the pretreatment solution is to be applied, that is, the mass of the fabric itself per unit area. Therefore, the amount of organic solvent, etc., applied is expressed as a relative value (mass%), where the total mass of the unit area is taken as 100% by mass, and the mass of the organic solvent, etc., applied to the unit area is expressed as the mass of the organic solvent, etc., applied to the unit area.

[0028] 1. Step of applying pretreatment solution to the fabric. In the step of applying a pretreatment solution to the fabric (hereinafter also referred to as the "pretreatment solution application step"), the pretreatment solution is applied to the surface of the fabric. In this case, the pretreatment solution may be applied to the entire surface of the fabric, or it may be applied selectively only to the areas to be dyed with sublimation dye, depending on the image to be recorded.

[0029] (1.1) Method of applying pretreatment solution Any known method can be used without particular limitation for applying the pretreatment solution to the fabric. Specifically, these include inkjet printing, mangle printing (pad or dipping), spray printing, and coating. The temperature of the pretreatment solution is not particularly limited, but it may be in the range of 15 to 30°C.

[0030] The amount of pretreatment solution applied to the fabric is not particularly limited and can be adjusted according to the content of solvents, etc., in the pretreatment solution and the amount of sublimation ink applied.

[0031] (Inkjet method) From the viewpoint of enabling the application of the pretreatment solution by an inkjet method to be carried out continuously with the sublimation ink application process, it is preferable. By applying a pretreatment solution using an inkjet method, it becomes possible to continuously apply the sublimation ink containing the sublimation dye described later.

[0032] (Mangle method) Furthermore, from the viewpoint of applying a predetermined amount of pretreatment solution in a short time, the mangle method or coater method is preferable. In the mangle method, the fabric is immersed in a pretreatment solution stored in a bathtub, and then the fabric is passed through a pressurized roller to wring it out, thereby removing excess pretreatment solution from the fabric and adjusting the amount of pretreatment solution applied.

[0033] (1.2) Components of the pretreatment solution The pretreatment solution according to the present invention is a pretreatment solution used in sublimation transfer printing. For fabrics containing hydrophilic natural fibers or synthetic cellulose fibers, it swells the fabric, widening the gaps between the fibers and making it easier for the sublimation dye to penetrate into the fibers. Furthermore, it contains nitrogen or an organic solvent as a solvent.

[0034] (1.2.1) Solvents The solvent contained in the pretreatment solution according to the present invention acts as a carrier for the transferred dye, making it easier for the dye to penetrate into the fibers. Furthermore, because it contains an organic solvent containing nitrogen or sulfur, it plays a role in easily trapping the dye in the sublimation ink between the fibers of the fabric, which has been appropriately swollen by the pretreatment solution.

[0035] (Organic solvents containing nitrogen or sulfur) Examples of organic solvents containing nitrogen or sulfur include amides such as N-methylformamide, N,N-dimethylformamide, N-methylacetamide, dimethylacetamide, N,N-dimethylacetamide, N-methoxy-N-methylacetamide, N-ethylacetamide, and N,N-diethylacetamide; heterocyclic compounds such as 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidinone, 2-pyrrolidinone (2-pyrrolidinone), and 1-methyl-2,5-pyrrolidinidione; and sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide.

[0036] Among these, N-methylacetamide, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, and 2-pyrrolidone (2-pyrrolidinone) are preferred because they can swell the fibers of the fabric and have high dye solubility, allowing the fabric to be dyed at a high concentration.

[0037] (Boiling point of organic solvents and temperature during the drying process of fabrics) By lowering the temperature during the fabric drying process (hereinafter also simply referred to as the "drying process"), which will be described later, than the boiling point of the organic solvent according to the present invention, the organic solvent is more likely to remain inside the fabric in an optimal amount.

[0038] The temperature in the drying process described later is preferably in the range of 100 to 200°C, and in particular, in the range of 100 to 130°C, from the viewpoint of preventing yellowing of the fabric due to the drying heat. Therefore, the boiling point of the organic solvent is preferably higher than 130°C and 260°C or lower.

[0039] Solvents with a boiling point higher than 130°C and below 260°C include, for example, N-methylacetamide (165°C), 1,3-dimethyl-2-imidazolidinone (225°C), dimethyl sulfoxide (189°C), and 2-pyrrolidone (2-pyrrolidinone) (245°C).

[0040] (Other organic solvents) The solvent may include other organic solvents besides the nitrogen or sulfur-containing organic solvents mentioned above, and it is preferable to include a water-soluble organic solvent from the viewpoint of moisture retention and viscosity adjustment. In particular, when applying a pretreatment solution to a fabric using an inkjet method, it is preferable that the pretreatment solution further contains a water-soluble organic solvent.

[0041] Examples of water-soluble organic solvents include alcohols (methanol, ethanol, propanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.), polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, glycerin, compounds represented by formula (1), etc.), and polyhydric alcohol ethers (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc.).

[0042] [ka]

[0043] (In formula (1), R 11 (Each of these represents either an ethylene glycol group or a propylene glycol group, and x, y, and z are all positive integers, with x+y+z=3 to 30.)

[0044] Since the fabric according to the present invention contains hydrophilic fibers, it is preferable that the pretreatment solution contains a high-boiling-point water-soluble organic solvent that prevents the pretreatment solution from becoming thicker due to drying, from the viewpoint of promoting the penetration of the pretreatment solution into the fabric and from the viewpoint of preventing damage to the injection stability in the inkjet method. The boiling point mentioned above is preferably 200°C or higher, and is preferably polyols or polyalkylene oxides.

[0045] Examples of polyols with a boiling point of 200°C or higher include dihydric alcohols such as 1,3-butanediol (boiling point 208°C), 1,6-hexanediol (boiling point 223°C), and polypropylene glycol; and trihydric or higher alcohols such as glycerin (boiling point 290°C) and trimethylolpropane (boiling point 295°C).

[0046] Examples of polyalkylene oxides with a boiling point of 200°C or higher include diethylene glycol monoethyl ether (boiling point 202°C), triethylene glycol monomethyl ether (boiling point 245°C), tetraethylene glycol monomethyl ether (boiling point 305°C), tripropylene glycol monoethyl ether (boiling point 256°C), and ethers of dihydric alcohols such as polypropylene glycol, as well as ethers of trihydric or higher alcohols such as glycerin (boiling point 290°C) and hexanetriol.

[0047] (1.2.2) Amount of organic solvent applied immediately after the step of applying the pretreatment solution The amount of organic solvent applied to the fabric immediately after the pretreatment solution application step is within the range of 10 to 150% by mass of the total mass of the fabric. The amount of dye added is preferably in the range of 5 to 95% by mass, and more preferably in the range of 15 to 50% by mass, in terms of staining concentration.

[0048] In the following sublimation ink coating process, when preparing the transfer medium, if the sublimation ink contains an organic solvent, and it is necessary to distinguish between the organic solvent contained in the sublimation ink and the organic solvent contained in the pretreatment solution, the organic solvent contained in the pretreatment solution will be referred to as "organic solvent α," and the organic solvent contained in the sublimation ink will be referred to as "organic solvent β."

[0049] For example, if the pretreatment solution according to the present invention is applied by an inkjet method, the amount of organic solvent α applied to the fabric is the amount applied itself. However, if it is applied by a mangle method, the amount of organic solvent α applied to the fabric is the amount of pretreatment solution remaining in the fabric after the organic solvent has been applied to the fabric and then squeezed to remove excess pretreatment solution.

[0050] When the amount of the aforementioned organic solvent applied to the fabric is within the above range, the fabric swells, widening the gaps between the fibers, which allows the sublimation dye to penetrate the inside of the fibers more easily, and thus increasing the dyeing concentration during sublimation ink transfer.

[0051] (1.2.3) Other ingredients The presence of an aromatic heterocyclic compound in the pretreatment solution according to the present invention is preferable from the viewpoint of easily capturing the dye in the sublimation ink within the fibers of the fabric and increasing the dyeing concentration. In addition to the solvent and aromatic heterocyclic compound mentioned above, other components may be included as needed, such as surfactants, preservatives, pH adjusters, and water.

[0052] (Aromatic heterocyclic compounds) The presence of an aromatic heterocyclic compound in the pretreatment solution according to the present invention is preferable from the viewpoint of easily capturing the dye in the sublimation ink within the fibers of the fabric and increasing the dyeing concentration.

[0053] In this invention, "aromatic heterocyclic compound" refers to an aromatic compound consisting of carbon and a heteroatom other than carbon as elements constituting the aromatic ring, but does not include cases where the elements constituting the aromatic ring are only carbon and the heteroatom constitutes a substituent that substitutes for the aromatic ring.

[0054] The aromatic heterocyclic compound according to the present invention preferably has oxygen, nitrogen, and sulfur atoms selected as heteroatoms constituting the aromatic ring, and more preferably is a nitrogen-containing heterocyclic compound with nitrogen atoms, from the viewpoint of easily capturing dyes in sublimation inks.

[0055] From the viewpoint of dye-catching ability, the aromatic heterocyclic compound according to the present invention is preferably contained in an amount of 1 to 30% by mass of the total pretreatment solution, and more preferably in an amount of 10 to 20% by mass.

[0056] The aforementioned aromatic heterocyclic compound is preferably low in molecular weight, from the viewpoint of dye capture within the fibers of the fabric. The aforementioned low molecular weight is, for example, within the range of 200 to 1000.

[0057] Furthermore, from the viewpoint of dye capture, the aromatic heterocyclic compound is preferably contained in an amount of 1 to 30% by mass relative to the entire pretreatment solution, and more preferably in an amount of 10 to 20% by mass.

[0058] Examples of the aromatic heterocyclic compounds include compounds having a pyrazole ring, triazole ring, imidazole ring, triazine ring, pyridine ring, indole ring, quinoline ring, pyrrole ring, thiophene ring, and thiazole ring. In particular, it is preferable that the compound be at least one selected from compounds having a pyrazole ring, triazole ring, and imidazole ring, from the viewpoint of supplementing the dye in the sublimation ink.

[0059] The aromatic heterocyclic compound preferably has three or more aromatic rings, and more preferably has five or more aromatic rings. Furthermore, it is preferable that the structure, either partially or entirely, consists of two aromatic rings linked to each other by single bonds.

[0060] When the aforementioned aromatic heterocyclic compound has these structures, its aromaticity increases, leading to stronger π-π interactions with sublimation dyes. This improves the dye-capturing ability and enhances the effect of suppressing discoloration and fading.

[0061] The aromatic heterocyclic compound according to the present invention preferably has a solubility of 10% by mass or more in the solvent contained together in the pretreatment solution at 25°C and 1 atm. The higher the solubility in the solvent, the easier it is for aromatic heterocyclic compounds to penetrate the fibers of the fabric in a dissolved state, thus improving dye capture ability and enhancing the effect of suppressing discoloration and fading.

[0062] Furthermore, the low molecular weight of the aromatic heterocyclic compound according to the present invention is preferable because it can capture sublimation dyes within the fibers of the fabric. Note that "low molecular weight" refers to a molecular weight that is, for example, within the range of 200 to 1000.

[0063] Specifically, examples include the following example compounds represented by the structural formulas below (1) to (13). However, the aromatic heterocyclic compounds according to the present invention are not limited to these.

[0064] [ka]

[0065] [ka]

[0066] (Surfactants) There are no particular restrictions on the type of surfactant, but when the ink components contain anionic compounds, the ionic nature of the surfactant is preferably anionic, nonionic, or betaine type.

[0067] Specifically, fluorine-based or silicone-based surfactants with high static surface tension reduction capabilities, anionic surfactants such as dioctyl sulfosuccinate and sodium dodecyl sulfate with high dynamic surface tension reduction capabilities, and nonionic surfactants such as relatively low molecular weight polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, acetylene glycols, Pluronic-type surfactants (Pluronic is a registered trademark), and sorbitan derivatives are preferably used. Furthermore, it is also preferable to use a fluorine-based or silicone-based surfactant in combination with a surfactant that has a high ability to reduce dynamic surface tension.

[0068] (Preservative) Examples of preservatives include aromatic halogen compounds (e.g., "Preventol CMK"), methylenedithiocyanates, halogenated nitrogen-sulfur compounds, and 1,2-benzisothiazolin-3-one (e.g., "PROXELGXL").

[0069] (pH adjuster) Examples of pH adjusters include citric acid, sodium citrate, hydrochloric acid, and sodium hydroxide.

[0070] (water) The water used is not particularly limited and may be deionized water, distilled water, or pure water. The water content in the pretreatment solution is preferably in the range of 0 to 95% by mass, and more preferably in the range of 0 to 50% by mass.

[0071] (1.2.4) Physical properties of the pretreatment solution The viscosity of the pretreatment solution at 25°C can be appropriately adjusted by the method of application to the fabric. For example, when applying a pretreatment solution using an inkjet method, the viscosity of the pretreatment solution is preferably in the range of 4 to 20 mPa·s. The viscosity of the pretreatment solution can be measured at 25°C using an E-type viscometer.

[0072] 2. The process of drying the fabric (drying process) In the drying process for the fabric, as described above, the pretreatment solution is applied to the fabric, and then the excess liquid medium (referring to organic solvents and water) is removed by drying the coating of the pretreatment solution applied to the fabric.

[0073] Immediately thereafter, the sublimation ink described later is transferred to the fabric. In this invention, the amount of the organic solvent remaining on the fabric immediately before the sublimation ink transfer is controlled in the drying process so that it is within the range of 3 to 40% by mass of the total mass of the fabric.

[0074] As mentioned above, when the organic solvent contained in the pretreatment solution is referred to as "organic solvent α" and the organic solvent contained in the sublimation ink is referred to as "organic solvent β", organic solvent α and organic solvent β may be of the same type.

[0075] Furthermore, in this specification, "the remaining amount of the organic solvent immediately before the transfer of the sublimation ink to the fabric" means "the remaining amount of the organic solvent α immediately before the transfer of the sublimation ink to the fabric."

[0076] However, the "amount of organic solvent remaining on the fabric immediately before the transfer of the sublimation ink" mentioned above does not include the amount of organic solvent β contained in the sublimation ink when the transfer medium is prepared in the sublimation ink coating process described later.

[0077] (2.1) Drying method for fabrics The drying method is not particularly limited, but heating with hot air, a hot plate, or a heat roller is preferred. From the viewpoint of removing the liquid medium sufficiently in a short time, heating and drying are more preferable.

[0078] The temperature in the process of drying the fabric (hereinafter also referred to as the "drying temperature") is preferably in the range of 100 to 200°C, and is particularly preferably in the range of 100 to 130°C from the viewpoint of preventing yellowing of the fabric due to the drying heat.

[0079] It is preferable that the above-mentioned drying temperature is lower than the boiling point of the organic solvent, from the viewpoint of making it easier to retain the organic solvent within an optimal amount inside the fabric.

[0080] Furthermore, it is preferable that the temperature at which the fabric is dried is lower than the heating temperature during the transfer process, from the viewpoint of suppressing discoloration of the white areas of the fabric due to heating.

[0081] (2.2) Types of fabrics The fibrous material constituting the fabric according to the present invention includes natural fibers (hydrophilic fibers) such as cellulose fibers (natural cotton), hemp, wool, and silk, and synthetic cellulose fibers, but it is particularly preferable to include natural or synthetic cellulose fibers in order to significantly exhibit the effects of the present invention.

[0082] Furthermore, to improve the fixation of the sublimation ink, a resin may be included, and preferably the resin is one that can be dyed with the sublimation dye described later. The above resins are appropriately selected depending on the type of fabric and the type of sublimation dye, but examples include hydrophobic resins, hydrophilic resins, and hydrophilic / hydrophobic resins having both hydrophobic and hydrophilic parts.

[0083] Furthermore, the fabric may consist of one type of natural fiber, or two or more types. Furthermore, other fibers not mentioned above may also be included.

[0084] Other examples of fibers may include synthetic fibers such as rayon, vinylon, nylon, acrylic, polyurethane, polyester, or acetate. The fabric may be made from these fibers in any form, such as woven, nonwoven, or knitted. Furthermore, the fabric may be a blended woven fabric or a blended nonwoven fabric made from two or more types of fibers.

[0085] As described above, the fabric preferably contains cellulose fibers, and if the fabric contains cellulose fibers and other fibers, it is preferable that the other fibers include polyester fibers.

[0086] The ratio of natural fibers and chemical fibers in the fibers constituting the fabric is expressed as the mass percentage of natural fibers and the mass percentage of chemical fibers relative to the total amount of fabric (total amount of natural and chemical fibers).

[0087] When the fabric according to the present invention contains natural fibers and optionally chemical fibers, it is preferable that the ratio of natural fibers in the fabric is in the range of 5 to 100% by mass, and the ratio of chemical fibers is in the range of 0 to 95% by mass.

[0088] For example, if the fabric contains cellulose fibers and polyester fibers, it is preferable that the cellulose fiber ratio is in the range of 35 to 100% by mass and the polyester fiber ratio is in the range of 0 to 65% by mass.

[0089] 3. The process of applying sublimation ink to the transfer medium. The process of applying sublimation ink to a transfer medium (hereinafter also referred to as the "sublimation ink application process") is a process of forming an image for transfer on the transfer medium by applying sublimation ink.

[0090] (3.1) Transfer medium The transfer medium used in the present invention is not particularly limited as long as it can form an ink layer on its surface and transfer that ink layer to a fabric, for example, one that does not interfere with the sublimation of the sublimation dye during transfer. As a transfer medium, paper in which an ink-receiving layer is formed on the surface using inorganic fine particles such as silica is preferred, and examples include inkjet-specific paper and transfer paper.

[0091] (3.2) Formation of transfer image (Method of applying sublimation ink to the transfer medium) Specifically, the transfer image to be formed on the transfer medium is formed by applying the aforementioned sublimation ink, which contains a sublimation dye and a liquid medium (organic solvent and water).

[0092] Specifically, first, sublimation ink is applied to the transfer medium using a known ink coating method, such as an inkjet method, and then dried to form an ink layer (transfer image) corresponding to the recorded image. As described above, using the inkjet method makes it possible to apply sublimation ink to the transfer medium with high precision.

[0093] The transfer medium used in the present invention is not particularly limited as long as it can form an ink layer on its surface and transfer that ink layer to a fabric, for example, one that does not interfere with the sublimation of the sublimation dye during transfer.

[0094] (3.3) Sublimation ink The sublimation ink according to the present invention contains a sublimation dye and may further contain other components besides the sublimation dye as needed, such as dispersants, solvents, surfactants, preservatives, pH adjusters, and water. The sublimation dyes mentioned above may or may not be crystallized.

[0095] (3.3.1) Sublimation dye In this invention, "sublimation dye" refers to a dispersible dye that is insoluble or sparingly soluble in water and has the property of sublimating when heated.

[0096] Furthermore, "insoluble or sparingly soluble in water" means that the solubility in water at 25°C is 10 mg / L or less, preferably 5 mg / L or less, and more preferably 1 mg / L or less.

[0097] There are no particular restrictions on the sublimation dyes used, and they include azo dyes, anthraquinone dyes, etc. Specifically, the following are some examples:

[0098] CIDisperse Yellow3, 4, 5, 7, 9, 13, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 63, 6 4, 66, 68, 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 114, 116, 118, 119, 122, 124, 126, 135, 140, 141, 149, 160, 162, 163, 164, 165, 17 9, 180, 182, 183, 186, 192, 198, 199, 202, 204, 210, 211, 215, 216, 218, 224, etc.

[0099] C.I. Disperse Orange 1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 47, 48, 49, 50, 53, 54, 55, 56, 57, 58, 59, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130, 139, 142, etc.

[0100] C.I. Disperse Red 1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122, 126, 127, 128, 131, 132, 134, 135, 137, 143, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 227, 229, 239, 240, 257, 258, 277, 278, 279, 281, 288, 289, 298, 302, 303, 310, 311, 312, 320, 324, 328, etc.

[0101] C.I. Disperse Violet 1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63, 69, 77, etc.

[0102] C.I. Disperse Green 9, etc. C.I. Disperse Brown 1, 2, 4, 9, 13, 19, etc.

[0103] CIDisperse Blue3, 7, 9, 14, 16, 19, 20, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79, 81, 82, 83, 87, 91, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128, 130, 139, 141, 142, 143, 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201, 205, 207, 211, 214, 224, 225, 257, 259, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 330, 333, 359, 360, etc. CIDisperseBlack1, 3, 10, 24 etc.

[0104] (molecular weight) The molecular weight of the sublimation dye is not particularly limited, but for example, when transferring sublimation ink coated on a transfer medium to fabric to form an image (sublimation printing), a small molecular weight (e.g., 200-350) is preferable from the viewpoint of facilitating the sublimation of the sublimation dye. On the other hand, from the standpoint of preventing the sublimation dye that has penetrated the fabric from easily leaching out, a molecular weight that is moderately large (for example, 350 to 500) is preferable.

[0105] (Average particle size) The average particle size of the sublimation dye in the sublimation ink is not particularly limited, but from the viewpoint of injection stability in the inkjet method, it may be, for example, 300 nm or less.

[0106] The average particle size can be determined using commercially available particle size analyzers employing methods such as light scattering, electrophoresis, and laser Doppler. Examples of particle size analyzers include the Malvern Zetasizer 1000.

[0107] (Content) The sublimation dye content in the sublimation ink is not particularly limited, but it is preferably in the range of 2 to 10% by mass relative to the sublimation ink.

[0108] If the sublimation dye content is 2% by mass or more, it is easier to form high-density images, and if it is 10% by mass or less, the viscosity of the sublimation ink does not become too high, so injection stability is less likely to be compromised.

[0109] From the same viewpoint as above, it is more preferable that the sublimation dye content be in the range of 5 to 10% by mass relative to the sublimation ink.

[0110] (3.3.2) Dispersants The dispersant can be selected according to the type of sublimation dye used. Examples of dispersants include formalin condensates of sodium creosote oil sulfonate, formalin condensates of sodium cresol sulfonate and sodium 2-naphthol-6-sulfonate, formalin condensates of sodium cresol sulfonate, formalin condensates of sodium phenol sulfonate, formalin condensates of sodium β-naphthol sulfonate, formalin condensates containing sodium β-naphthalene sulfonate and sodium β-naphthol sulfonate, alkylene oxides containing ethylene oxide and propylene oxide, alkylable compounds containing fatty alcohols, fatty amines, fatty acids, phenols, alkylphenols and carboxylic acid amines, lignin sulfonates, sodium paraffin sulfonate, copolymers of α-olefins and maleic anhydride, and known comb-type block polymers.

[0111] Examples of comb-type block polymers include "DISPERBYK-190," "DISPERBYK-194N," "DISPERBYK-2010," "DISPERBYK-2015," and "BYK-154" from BIC Chemie ("DISPERBYK" and "BYK" are registered trademarks of the company).

[0112] The content of the dispersant is not particularly limited, but it is preferably in the range of 20 to 200 parts by mass per 100 parts by mass of the sublimation dye. When the dispersant content is 20 parts by mass or more, the dispersibility of the sublimation dye tends to be higher, and when it is 200 parts by mass or less, the decrease in injection properties due to the dispersant tends to be suppressed.

[0113] (3.3.3) Organic Solvents The solvent contained in the sublimation ink is not particularly limited, but is preferably a water-soluble organic solvent, and the same type as the pretreatment solution described above can be used.

[0114] The organic solvent used is the aforementioned organic solvent β, and the organic solvent α and the organic solvent β may be of the same type.

[0115] The content of the water-soluble organic solvent is preferably in the range of 20 to 70% by mass relative to the sublimation ink. If the water-soluble organic solvent content is 20% by mass or more relative to the sublimation ink, the dispersibility and injection properties of the sublimation dye are more easily improved, while if it is 70% by mass or less, the drying properties of the sublimation ink are less likely to be impaired.

[0116] Since the fabric according to the present invention contains hydrophilic fibers, it is preferable that it contains a water-soluble organic solvent that prevents the sublimation ink from becoming thicker due to drying, from the viewpoint of promoting the penetration of sublimation ink into the fabric and minimizing the impairment of injection stability in the inkjet method. Therefore, it is preferable that the sublimation ink contains a high-boiling-point solvent with a boiling point of 200°C or higher.

[0117] (3.3.4) Surfactants, preservatives, pH adjusters and water The surfactants, preservatives, pH adjusters, and water used are the same as those used in the pretreatment solution.

[0118] (3.3.5) Physical properties of sublimation inks The viscosity of the sublimation ink at 25°C is not particularly limited, as long as it is sufficient for good ejection by the inkjet method, but it is preferably in the range of 3 to 20 mPa·s, and more preferably in the range of 4 to 12 mPa·s. The viscosity of sublimation ink can be measured at 25°C using an E-type viscometer.

[0119] 4. The process of transferring sublimation ink from the transfer medium to the fabric. The process of transferring sublimation ink from a transfer medium to a fabric (hereinafter also referred to as the "transfer process") involves bringing the surface of the transfer image formed on the transfer medium in the sublimation ink coating process into contact with the surface of the fabric to which the pretreatment solution has been applied (pretreatment surface), and then heating (heat pressing) it to transfer the image.

[0120] This allows the sublimation dye in the transfer image formed on the transfer medium to be transferred to the fabric. Specifically, the pre-treatment solution applied to the fabric is sublimated and transferred to the fabric to dye it, thereby recording the desired image on the fabric.

[0121] (4.1) Heating temperature during transfer From the viewpoint of suppressing discoloration of the white areas of the fabric due to heating, it is preferable that the temperature at which the fabric is dried is lower than the heating temperature during the transfer process. In the drying process, the temperature is preferably in the range of 100 to 130°C, especially from the viewpoint of preventing yellowing of the fabric due to the drying heat; therefore, the heating temperature during transfer is preferably higher than 130°C.

[0122] In particular, it is preferable that the heating temperature during the transfer is higher than the boiling point of the solvent contained in the pretreatment solution, as this allows the solvent to be removed by the transfer, the dye to be more fixed, and the bleed-out suppression effect to be enhanced.

[0123] The heating temperature (heat press temperature) during transfer depends on the sublimation temperature of the sublimation dye, but is preferably in the range of 180 to 210°C. This removes excess organic solvents, further fixes the dye, and enhances the effects of the present invention.

[0124] Furthermore, the pressing pressure for flat molds is 200-500 g / cm². 2 Within the range of 2-6 kg / cm² for continuous applications. 2 It is preferable that it be within the range. Furthermore, the pressing time is preferably within the range of 30 to 180 seconds, although this also depends on the temperature.

[0125] (4.2) Amount of organic solvent remaining on the fabric immediately before sublimation ink transfer The fabric containing the pretreatment solution according to the present invention, after being treated with the pretreatment solution as described above, can be further dried in a drying process for the fabric (hereinafter also referred to as the "drying process") to remove excess pretreatment solution, thereby suppressing yellowing of the white areas of the transfer image and discoloration of the sublimation ink in a high-humidity environment. To obtain the above effects, the amount of pretreatment solution is controlled in the drying step so that the amount of organic solvent remaining on the fabric immediately before the transfer of the sublimation ink in the transfer step is within the range of 3 to 40% by mass of the total mass of the fabric.

[0126] Furthermore, the "amount of the organic solvent remaining immediately before the transfer of the sublimation ink to the fabric" refers to the amount of the organic solvent α remaining immediately after the drying process.

[0127] II. Image Recording System The present invention relates to an image recording system for dyeing a fabric containing natural fibers using a sublimation transfer method, comprising means for applying a pretreatment solution to the fabric, means for drying the fabric, means for applying sublimation ink to a transfer medium, and means for transferring the sublimation ink from the transfer medium to the fabric, wherein the pretreatment solution contains an organic solvent containing nitrogen or sulfur as a solvent, the amount of the organic solvent applied immediately after applying the pretreatment solution is in the range of 10 to 150% by mass of the total mass of the fabric, and the amount of the organic solvent remaining in the transfer means immediately before transferring the sublimation ink to the fabric is in the range of 3 to 40% by mass of the total mass of the fabric. Furthermore, the image recording method of the present invention described above is suitably used in the above-mentioned image recording system.

[0128] Figure 1 is a schematic diagram showing an example of the image recording system of the present invention. The image recording system (300) shown in Figure 1 is an image recording system that prints images onto fabric using a continuous transfer printing method.

[0129] Figure 1 is an example of the image recording system (300) of the present invention, and is not limited to this configuration.

[0130] This image recording system (300) comprises a pretreatment liquid application device (100) and a sublimation ink coating device (200), and includes a transfer unit (301), a peeling unit (302), a transfer medium recovery unit (205), a fabric recovery unit (105), and a control unit (106), etc.

[0131] 1. Means for applying pretreatment solution As a means for applying the pretreatment solution according to the present invention, for example, the following pretreatment solution application apparatus can be used.

[0132] Figure 2 is a block diagram showing the internal configuration of the pretreatment liquid application device (100) of the present invention.

[0133] (Pretreatment liquid application device) The pretreatment liquid application device (100) includes a fabric feeding unit (101), a conveying unit (102), a pretreatment liquid application unit (103), a pretreatment liquid drying unit (104), a fabric retrieval unit (105), a control unit (106), and the like.

[0134] The pretreatment liquid application device (100), under the control of the control unit (106), transports the fabric (C) from the fabric feeding unit (101) to the pretreatment liquid application unit (103), applies the pretreatment liquid to the fabric (C) in the pretreatment liquid application unit (103), dries the fabric to which the pretreatment liquid has been applied (hereinafter also simply referred to as "fabric (C1)") in the drying unit (104), produces a fabric (C2) (hereinafter also simply referred to as "fabric (C2)") from which the excess pretreatment liquid has been removed, and transports the fabric (C2) to the fabric recovery unit (105) located downstream of the peeling unit (302). Then, the fabric (N) (hereinafter also simply referred to as "fabric (N)") to which the transfer image has been heat-transferred, which has been peeled off at the peeling section (302), is recovered while being wound up.

[0135] (Pre-treatment solution application section) The pretreatment liquid applied by the pretreatment liquid application unit (103) described above contains an organic solvent containing nitrogen or sulfur as a solvent, and the amount of the organic solvent applied immediately after the means for applying the pretreatment liquid is adjusted to be within the range of 10 to 150% by mass of the total mass of the fabric. The components contained in the pretreatment solution are as described above.

[0136] Subsequently, as will be described later, the sublimation ink coating apparatus (200) transfers the transfer image recorded on the transfer medium to the surface of the fabric (C2) to which the pretreatment solution has been applied (see Figure 1).

[0137] [Method for applying pretreatment solution] The method of applying the pretreatment solution in the pretreatment solution application unit (103) is not particularly limited and may be any of the following: spray method, mangle method (pad method), coating method, or inkjet method.

[0138] For example, in the sublimation ink coating apparatus (200) described later, the inkjet method is preferred from the viewpoint of enabling the process to be carried out continuously with the sublimation ink coating process, and the mangle method or coater method is preferred from the viewpoint of applying a predetermined amount of pretreatment solution in a short time.

[0139] In the mangle method, the amount of pretreatment solution applied is adjusted by immersing the fabric in a pretreatment solution stored in a bathtub and then squeezing it. The temperature of the pretreatment solution is not particularly limited, but it is preferably within the range of 15 to 30°C.

[0140] (Control Unit) The control unit (106) controls the application conditions of the pretreatment solution based on the fabric information. Specifically, it is preferable to control the amount of pretreatment solution applied based on fabric information (e.g., fiber ratio, weight, and fiber type of the fabric). The control unit (106) receives fabric information entered by the user when they operate the control unit (not shown). The control unit (106) also includes a CPU (107), RAM (108), and ROM (109). The CPU (107) reads various programs and data from storage devices such as the ROM (109) according to the processing content and executes them, and controls the operation of each part of the pre-treatment liquid application device (100) according to the executed processing content. RAM (108) temporarily stores various programs and data processed by the CPU (107). ROM (109) stores various programs and data that are read by the CPU (107), etc.

[0141] Specifically, the control unit (106) performs the following processing on the pretreatment liquid application device (100). In other words, the control unit (106) operates the pretreatment liquid application unit (103) so that the amount of pretreatment liquid applied is a predetermined amount according to the fabric information input from the operation unit (not shown), and applies the pretreatment liquid to the fabric (C).

[0142] (Fabric dispensing section) The fabric (C) is placed in the fabric feeding unit (101) located upstream of the pretreatment liquid application unit (103) in the transport direction. The fabric dispensing unit (101) includes a rotating shaft on which a roll of fabric (C) is mounted, and a motor (not shown) that rotates the rotating shaft in a predetermined direction. The fabric feeding unit (101) feeds the fabric (C) downstream in the conveying direction along the rotation of the rotating shaft by driving a motor.

[0143] (Transportation section) The conveying unit (102) conveys the fabric (C) that has been unfed from the fabric unfed unit (101). In Figure 1, the fabric (C) is transported by conveyor rollers, but for example, the fabric (C) may be attached to a conveyor belt for transport.

[0144] 2. Means for drying fabrics (Pre-treatment solution drying section) The pretreatment liquid drying unit (104) dries the fabric (C1) to which the pretreatment liquid has been applied in the pretreatment liquid application unit (103), and removes any excess pretreatment liquid from the fabric (C1).

[0145] The drying method is not particularly limited, but heating by hot air, a hot plate, or a heat roller is preferred. From the viewpoint of removing solvent components sufficiently in a short time, heat drying is more preferable.

[0146] The temperature used to dry the fabric (C1) to which the pretreatment solution has been applied (hereinafter also referred to as the "drying temperature") is preferably in the range of 100 to 200°C, and in particular, in the range of 100 to 130°C, from the viewpoint of preventing yellowing of the fabric due to the drying heat.

[0147] It is preferable that the drying temperature is lower than the boiling point of the organic solvent, from the viewpoint of making it easier to retain the organic solvent within an optimal amount inside the fabric, and it is also preferable that the drying temperature is lower than the heating temperature during transfer, from the viewpoint of suppressing discoloration of the white areas of the fabric due to heating.

[0148] (Fabric Collection Department) The fabric recovery unit (105) is located downstream of the pretreatment liquid drying unit (104). In the pretreatment liquid drying unit (104), the transfer image formed on the transfer medium by the transfer unit (301) is thermally transferred to the fabric (C2), and the fabric (N) is recovered while being wound up.

[0149] 3. Means for applying sublimation ink to a transfer medium The sublimation ink coating apparatus (200) is an apparatus that forms a transfer image (ink layer) by coating a transfer medium with sublimation ink using an inkjet recording unit (203), heat-transfers the transfer image formed on the transfer medium to the fabric (C2) using a transfer unit (301) in a pre-treatment liquid drying unit (104), and recovers the remaining used transfer paper substrate (P3) using a transfer medium recovery unit (205).

[0150] Specifically, it comprises a transfer medium feeding unit (201), an inkjet recording unit (203), an ink drying unit (204), a transfer unit (301), and a transfer medium recovery unit (205). Furthermore, it is preferable to include a peeling section (302) and a transport section (202) for transporting the transfer medium.

[0151] The transfer medium dispensing unit (201) is equipped with a roll-shaped transfer paper substrate (P) as the transfer medium. The transfer paper substrate (P) is mounted such that when it is fed out by driving a motor (not shown), the transfer surface of the transfer paper substrate (P) faces the inkjet head of the inkjet recording unit (203).

[0152] The inkjet recording unit (203) forms a transfer image (ink image) on a transfer paper substrate (P) fed out from the transfer medium feeding unit (201) using an inkjet head, thereby forming a transfer paper (P1) after the transfer image has been formed (hereinafter also simply referred to as "transfer paper (P1)").

[0153] The ink drying section (204) is located downstream of the inkjet recording section (203) and dries the transfer paper (P1) at a temperature lower than the crosslinking temperature of the fixing resin contained in the transfer image (ink image).

[0154] 4. Means for transferring the sublimation ink from the transfer medium The transfer section (301) preferably comprises, for example, a heating roller (301a) having a heat source inside, and a pressure roller (301b) that is pressed against the heating roller (301a).

[0155] The transfer paper (P1) coated with sublimation ink is dried by the ink drying unit (204) (hereinafter, this dried transfer paper will also be referred to as "transfer paper (P2)"), and in a state where it is stacked on the fabric (C2) with the image surface (the surface on which the transfer image is formed) facing each other by the pretreatment liquid application device (100), it is subjected to heating and pressurizing treatment by passing through the nip portion of the heating roller (301a) and the pressure roller (301b), thereby transferring the sublimation ink from the transfer paper (P2) to the fabric (C2), and forming a fabric (N) which is a transfer image formed by heat transfer of the transfer image.

[0156] At this time, the amount of the organic solvent remaining on the fabric (C2) immediately before the sublimation ink transfer is adjusted by the aforementioned drying process to be within the range of 3 to 40% by mass relative to the total mass of the fabric (C2).

[0157] As mentioned above, "the amount of organic solvent remaining immediately before sublimation ink transfer" refers to the amount of organic solvent α used in the pretreatment liquid application step. Furthermore, the organic solvent α and the organic solvent β may be of the same type.

[0158] However, the "amount of organic solvent remaining on the fabric immediately before sublimation ink transfer" mentioned above does not include the amount of organic solvent β contained in the sublimation ink when the transfer medium is prepared in the sublimation ink coating process described above.

[0159] The peeling section (302) is located downstream of the transfer section (301). The peeling section (302) peels off the used transfer paper substrate (P3) after the transfer process has been performed in the transfer section (301).

[0160] The transfer medium recovery unit (205) is located downstream of the peeling unit (302). Then, the used transfer paper substrate (P3) that has been peeled off from the laminate at the peeling section (302) is recovered while being wound up.

[0161] The image recording system (300) shown in Figure 1 is a continuous system in which a fabric (C) is unfurled and a pretreatment solution is applied, while a transfer paper substrate (P) is unfurled to form an image for transfer, and the transfer paper (P2) is dried by an ink drying unit (204). Then, the fabric (C2) from which the excess pretreatment solution has been removed is stacked with the transfer paper (P2) to form a laminate, and then the transfer image is transferred onto the fabric (C2) by a transfer unit (301). After that, the transfer paper (P2) is peeled off from the fabric (C2). However, a batch system in which the laminate formed by stacking the transfer paper (P2) on the fabric (C2) is pressed from above and below may also be used. [Examples]

[0162] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples, the units "parts" or "%" are used, and unless otherwise specified, they represent "parts by mass" or "mass%".

[0163] [1. Preparation of pretreatment solution] Pretreatment solutions No. 1 to 4 were prepared by mixing a solvent (the organic solvent contained in the pretreatment solution is referred to as "organic solvent α"), an aromatic heterocyclic compound, a surfactant, and ion-exchanged water to the compositions shown in Table I below. The compound used as an aromatic heterocyclic compound is the example compound (8) described above. In Table I, "N or S" represents nitrogen or sulfur, "○" indicates that nitrogen or sulfur is present, and "×" indicates that nitrogen or sulfur is not present.

[0164] [Table 1]

[0165] [2. Preparation of sublimation ink] [2.1] Preparation of dispersion Disperbyk-190 (manufactured by Bic Chemie Japan Co., Ltd., acid value 10 mg KOH / g) as a dispersant and deionized water were mixed and stirred until homogeneous. Then, Disperse Red 60 was added as a sublimation dye and pre-mixed. The mixture was dispersed until the Z-average particle size, measured by dynamic light scattering, was in the range of 150-200 nm, to prepare a dispersion with a sublimation dye concentration of 20% by mass.

[0166] At this time, the amounts of the dispersant, deionized water, and sublimation dye were adjusted so that the sublimation dye content was 20% by mass relative to the total mass of the dispersant, and the amount of solids in the dispersant was 30% relative to the total mass of the dispersible dye.

[0167] The Z-average particle size was measured using dynamic light scattering, with a sand grinder filled with 0.5 mm zirconia beads at a volume percentage of 50%, using a Zetasizer 1000, manufactured by Malvern ("Zetasizer" is a registered trademark of the company).

[0168] [2.2] Preparation of sublimation ink The obtained dispersion was mixed with 30% by mass of glycerin, 10% by mass of ethylene glycol, 25% by mass of glycerin, 25% by mass of ethylene glycol as solvents (the organic solvent contained in the sublimation ink is referred to as "organic solvent β"), appropriate amounts of Proxel GXL as a preservative, and sodium citrate hydrate as a pH adjuster. The mixture was then mixed with deionized water to a total of 100% by mass, and filtered through a 1 μm mesh filter to obtain ink [1] (magenta sublimation ink).

[0169] [3. Image Formation (Examples and Comparative Examples)] [3.1] Preparation of image formation [1]: Example 1 [3.1.1] Step of applying pretreatment solution to the fabric (pretreatment solution application step) For the fabric, we used cotton broadcloth 40 (100% cotton). Then, the pretreatment solution No. 1 prepared as described above was applied to the fabric using the mangle method.

[0170] Specifically, the fabric was immersed in a bathtub filled with the pretreatment solution No. 1 prepared as described above, and then the excess pretreatment solution was squeezed out with a mangle roll at a pick-up rate (amount of treatment solution applied relative to the weight of the fabric) of 80%. Furthermore, the temperature inside the bathtub was set to 20-25°C.

[0171] The amount of the organic solvent α applied immediately after the step of applying the above-mentioned pretreatment solution was 15% by mass relative to the total mass of the fabric.

[0172] [3.1.2] Drying process of the fabric A pre-treated fabric [1] was prepared by applying pre-treatment solution No. 1 to a fabric, placing it in a constant-temperature dryer for a certain period of time, and removing excess pre-treatment solution with hot air. The drying conditions were a drying temperature of 200°C and a drying time of 40 seconds. The remaining amount of organic solvent α after drying was 3% by mass.

[0173] [3.1.3] Step of applying sublimation ink to the transfer medium Next, an inkjet printer equipped with an inkjet head (Konica Minolta head KM1024iMAE) was prepared as the image forming apparatus.

[0174] Then, the ink [1] prepared above was ejected from the nozzle of the inkjet head to form a solid image on A4 sublimation transfer paper with adhesive (manufactured by Systemgraphi) as transfer paper.

[0175] Specifically, an image (200mm x 200mm in total) including a fine grid, gradation, and solid areas was formed using a main scan of 540dpi and a sub-scan of 720dpi. dpi represents the number of ink droplets (dots) per inch, or 2.54cm. The ejection frequency was set to 22.4kHz. Afterwards, the ink-coated transfer paper was dried in a dryer at 50-80°C for 30 seconds.

[0176] At this time, the total remaining amount of organic solvent β contained in the sublimation ink (ink [1]) applied to the transfer paper (total remaining amount of glycerin and ethylene glycol) was 5% by mass.

[0177] [3.1.4] A process of transferring sublimation ink from a transfer medium to a fabric (sublimation ink transfer process) Next, the transfer paper coated with ink [1] was transferred using a transfer device (heat press) at a transfer temperature of 200°C, a transfer time of 50 seconds, and a press pressure of 300 g / cm². 2 By applying pretreatment solution No. 1 to the fabric and then applying heat-pressing, the ink [1] on the transfer paper was transferred onto the pretreatment fabric [1] to obtain an image-forming product [1].

[0178] The amount of organic solvent α remaining immediately before transferring the ink [1] on the transfer paper onto the pre-treated fabric [1] was defined as the amount of organic solvent α remaining after drying in the fabric drying process. The remaining amount of the above-mentioned organic solvent α was 3% by mass relative to the total mass of the pre-treated fabric [1].

[0179] [3.2] Preparation of image formations [2] to

[26] : Examples 2 to 15 and Comparative Examples 1 to 11 Image formations [2] to

[26] were prepared in the same manner as image formation [1], except that the type of fabric, type of pretreatment solution, method of application, amount of organic solvent α applied immediately after the application of the pretreatment solution, drying temperature, drying time in the drying process, amount of organic solvent α remaining after drying, and transfer temperature and transfer time in the sublimation ink transfer process were changed to the conditions shown in Table II below.

[0180] [4. Evaluation] [4.1] Dyeing property (dyeing density) (Evaluation method) Using the image forming products [1] to

[26] , the portion where the sublimation ink was transferred was measured with a spectrophotometer (manufactured by Konica Minolta), the K / S value was calculated by the following formula, and the dyeing property was evaluated according to the following evaluation criteria. The evaluation results are as shown in Table II. In the following evaluation criteria, A, B, C, and D were considered to have no practical problems.

[0181] Note that the K / S value is an index of the surface color density defined by the following formula. The larger the K / S value, the higher the color density, and the smaller the K / S value, the lower the color density.

[0182] Kubelka - Munk formula: K / S = (1 - R) 2 / 2S (K: Absorption coefficient of light, S: Scattering coefficient of light, R: Surface reflectance)

[0183] (Evaluation criteria) A The K / S value is 15 or more. B The K / S value is 12 or more and less than 15. C The K / S value is 10 or more and less than 12. D The K / S value is 8 or more and less than 10. E: The K / S value is less than 8.

[0184] [4.2] Degree of yellowing suppression (Evaluation method) The L * a * b * values in the color space of L * value, a [[ID= fifty-two]] * value, and b * values were measured with a spectrophotometer (CM - 25d manufactured by Konica Minolta, measurement light source: D65). Also, using the image forming products [1] to

[26] , the L * a * b *L in color space * value, a * value, and b * The value was measured.

[0185] L size of untreated fabric * value, a * value, and b * Values ​​and L of the image formations [1] to

[26] * value, a * value, and b * The difference from the value is ΔL * Value, Δa * Value and Δb * The value is used, and the color difference ΔE is calculated using the following formula. * The ab values ​​were calculated, and the degree of yellowing suppression was evaluated according to the following evaluation criteria. The evaluation results are shown in Table II. In the evaluation criteria below, A, B, and C were deemed to be practically acceptable.

[0186] (Formula) ΔE * ab={(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2} 1 / 2

[0187] (Evaluation Criteria) A ΔE * The ab value is less than 1. B ΔE * The ab value is between 1 and 2. C ΔE * The ab value is between 2 and 3. D ΔE * The ab value is between 3 and 4. E ΔE * The ab value is between 4 and 5. F ΔE * The ab value is 5 or higher.

[0188] [4.3] Degree of discoloration in high humidity environments (Evaluation method) Using the image-forming materials [1] to

[26] , the L of the area to which the sublimation ink was transferred* a * b * L in color space * value, a * Value and b * The values ​​were measured using a spectrophotometer (Konica Minolta CM-25d, measurement light source: D65), and then the image-forming objects [1] to

[26] were left in an environment of 20°C and 95%RH for 7 days before being subjected to another L test. * value, a * Value and b * The value was measured. As measured above, L before being left for 7 days * value, a * Value and b * Value and L after 7 days * value, a * Value and b * The difference from the value is ΔL * Value, Δa * Value and Δb * The value is used, and the color difference ΔE before and after standing is calculated using the following formula. * The ab values ​​were calculated, and the degree of discoloration under high humidity conditions was evaluated according to the following evaluation criteria. The evaluation results are shown in Table II. In the evaluation criteria below, A, B, C, and D were deemed to be practically acceptable.

[0189] (Formula) ΔE * ab={(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2} 1 / 2

[0190] (Evaluation Criteria) A ΔE * The ab value is less than 1. B ΔE * The ab value is between 1 and 2. C ΔE * The ab value is between 2 and 3. D ΔE * The ab value is between 3 and 4. E ΔE * The ab value is between 4 and 5. F ΔE * The ab value is 5 or more.

[0191]

Table 2

[0192] [5. Summary ] As is clear from Table II, it can be seen that the examples are comprehensively superior to the comparative examples in terms of dyeing property, the degree of suppressing yellowing of the white background portion, and the degree of discoloration in a high-humidity environment.

Explanation of symbols

[0193] 100 Pretreatment liquid application device 101 Fabric feeding section 102 Conveying section 103 Pretreatment liquid application section 104 Pretreatment liquid drying section 105 Fabric recovery section 106 Control section 107 CPU 108 RAM C1 Fabric with pretreatment liquid applied 200 Sublimation ink coating device 201 Transfer medium feeding section 202 Conveying section 203 Inkjet recording section 204 Ink drying section 205 Transfer medium recovery section 300 Image recording system 301 Transfer section 301a Heating roller 301b Pressing roller 302 Peeling section C Fabric C1 Fabric with pretreatment liquid applied C2 Fabric with excess pretreatment liquid removed P Transfer paper base material P1 Transfer paper (transfer paper after image formation for transfer) P2 Transfer paper dried by the ink drying section P3 Used transfer paper base material N Fabric with heat-transferred image for transfer

Claims

1. An image recording method for dyeing fabrics containing natural fibers using a sublimation transfer method, The process involves applying a pretreatment solution to the aforementioned fabric, The process of drying the aforementioned fabric, The process involves applying sublimation ink to the transfer medium, The process includes transferring the sublimation ink from the transfer medium to the fabric, The aforementioned pretreatment liquid contains an organic solvent containing nitrogen or sulfur as a solvent, The amount of the organic solvent applied immediately after the step of applying the pretreatment solution is within the range of 10 to 150% by mass of the total mass of the fabric, and In the transfer process, the amount of the organic solvent remaining immediately before the transfer of the sublimation ink to the fabric is within the range of 3 to 40% by mass of the total mass of the fabric. An image recording method characterized by the following:

2. The temperature during the drying process of the fabric is lower than the boiling point of the organic solvent. The image recording method according to feature 1.

3. The temperature at which the fabric is dried is lower than the heating temperature during the transfer process. The image recording method according to claim 1 or 2.

4. The aforementioned pretreatment solution contains an aromatic heterocyclic compound. The image recording method according to feature 3.

5. The aforementioned pretreatment liquid is applied by an inkjet method. The image recording method according to feature 3.

6. An image recording system for dyeing fabrics containing natural fibers using a sublimation transfer method, The means for applying a pretreatment solution to the aforementioned fabric, A means for drying the aforementioned fabric, A means for applying sublimation ink to a transfer medium, The fabric comprises means for transferring the sublimation ink from the transfer medium, The pretreatment solution contains an organic solvent containing nitrogen or sulfur as a solvent, and the amount of the organic solvent applied immediately after the means for applying the pretreatment solution is controlled to be within the range of 10 to 150% by mass of the total mass of the fabric. The transfer means includes a control means for controlling the amount of the organic solvent remaining on the fabric immediately before the transfer of the sublimation ink to the fabric to be within the range of 3 to 40% by mass of the total mass of the fabric. Image recording system.

Images