JP6676892B2 - Direct sublimation printing method - Google Patents

Description

  The present invention relates to a direct sublimation printing method.

  In textile printing by an inkjet recording method (hereinafter, also simply referred to as "ink-jet printing"), a method of performing printing using a dye sublimating at a certain temperature or higher (hereinafter, also simply referred to as "sublimable dye") (hereinafter, referred to as "sublimation dye"). (Hereinafter simply referred to as “sublimation printing method”)) (Patent Document 1 and the like). In the sublimation printing method, the sublimation dye is sublimated and diffused and fixed between the fibers, so that the color development of the dye in the printed fabric can be enhanced.

  Conventionally, as a sublimation printing method, an ink containing a sublimable dye is ejected from an ink jet recording head (hereinafter, also simply referred to as a “recording head”) to land on an intermediate transfer medium such as transfer paper. A method has been known in which a sublimable dye in ink that has landed on a transfer medium is sublimated and diffused and fixed on a polyester fabric. However, since the intermediate transfer medium is discarded after use, improvement has been demanded from the viewpoint of resource conservation. Recently, a direct sublimation printing method has been developed in which an ink containing a sublimable dye is directly landed on a fabric without using an intermediate transfer medium, and the fabric is heated to diffuse and fix the sublimable dye between fibers. Was. This method is not only a very useful method from the viewpoint of resource protection, but also allows the ink to land directly on the fabric, so that it can be dyed even on uneven fabrics such as knits. There are advantages such as that the back surface of the fabric can be dyed.

  However, in the direct sublimation printing method, since the ink is landed directly on the fiber, the ink bleeds and becomes indistinct at a boundary, that is, a so-called bleeding problem occurs. In order to prevent this, it is common to apply a pretreatment in which a polymer called a sizing agent is preliminarily applied to the fiber, but it is necessary to wash the polymer later by reducing and removing the polymer. Was.

  Further, as a method of suppressing bleeding in the ink jet printing transfer, there is known a technique of using a special color ink different from a dye contained in these inks in addition to inks of yellow, magenta, and cyan (Patent Document 2). Such).

JP 2009-57416 A JP-A-5-209378

  In the direct sublimation printing method, as described above, an image is formed by performing a pretreatment with a sizing agent. Therefore, in the direct sublimation printing method, a washing step for removing the paste is required. This washing process is considered to have an adverse effect on the environment, and a printing method using no paste has been desired.

  In the sublimation printing method, it takes time to sublimate the dye. For this reason, fabrics that are weak to heat have disadvantages such as a decrease in the strength of the fabric during the sublimation of the dye, and a printing method in which the strength of the fabric does not easily decrease has been desired.

  The method described in Patent Document 2 is a printing method using a reactive dye or an acid dye. Since these printing methods do not use a glue, a washing step is not necessary in the first place, and there is no need to heat the fabric as in the direct sublimation printing method. Therefore, those skilled in the art have no motivation to apply the method described in Patent Document 2 to direct sublimation printing, and even if the method described in Patent Document 2 is applied to direct sublimation printing, sufficient dyeing can be achieved. It was not clear whether this was possible.

  In view of the above circumstances, the present invention provides a direct sublimation printing method that suppresses bleeding of an image without using a sizing agent and that can also suppress a decrease in the tensile strength of a fabric as compared with the conventional method. Its purpose is to

In view of the above problems, the present invention relates to a direct sublimation printing method described below.
[1] A step of ejecting droplets of a plurality of types of inks containing a sublimable dye, a dispersant, and water from an ink jet recording head and landing them on an image forming portion of a fabric containing polyester fibers, respectively. When,
Heating the image forming site of the fabric on which the plurality of types of ink droplets have landed to a temperature at which any of the sublimable dyes contained in the plurality of types of inks sublimates. At
The ink includes one or more process color inks selected from the group consisting of yellow ink, magenta ink, cyan ink and black ink, and special color inks,
At least a portion of the process color ink droplets and at least a portion of the special color ink droplets land on the same region in the image forming portion,
The method, wherein the image forming site is substantially free of a glue.
[2] The feature color ink according to [1], wherein the special color ink is one or more inks selected from the group consisting of red ink, orange ink, green ink, blue ink, pink ink, and violet ink. the method of.
[3] In the landing step, a maximum landing amount (ml) of each of the plurality of inks per mass (g) of the fabric at the image forming portion is 0.033 ml / g or more and 0.100 ml / g. g or less, The method of [1] or [2].
[4] The method according to any one of [1] to [3], wherein the heating time in the heating step is 15 seconds or more and 180 seconds or less.
[5] A shrinkage ratio of the image forming portion, which is determined by a dry heat ironing method described in JIS L 1057 at an iron temperature of 140 ° C., is 5.0% or more, [1] ] The method according to any one of [4] to [4].
[6] The method according to any one of [1] to [5], wherein the image forming site further includes a polyurethane fiber or a polylactic acid fiber.

  ADVANTAGE OF THE INVENTION According to this invention, the direct sublimation printing method which makes it possible to suppress the blur of an image and the fall of the tensile strength of a cloth compared with the former is provided.

  According to the direct sublimation printing method of the present invention (hereinafter, also simply referred to as “the printing method of the present invention”), an image of a fabric is formed using a plurality of types of inks containing a sublimable dye, a dispersant, and water. An image is formed in a region to be formed (hereinafter, also simply referred to as “image forming portion”) by a direct sublimation printing method. In the textile printing method of the present invention, the plurality of types of inks include a process color ink (yellow ink, magenta ink, cyan ink or black ink), and a special color ink. At least a part of the droplet of the process color ink and at least a part of the droplet of the special color ink land on the same area in the image forming portion. In the printing method of the present invention, the image forming portion includes a polyester fiber, and at least the image forming portion of the cloth is not pre-treated. In addition, the special color ink means an ink that exhibits a color tone other than yellow, magenta, cyan, or black when a fabric is printed.

  According to a new finding of the present inventors, by performing printing using a special color ink in addition to the process color ink, even in the direct sublimation printing method, the bleeding of the printed image can be reduced, and the cloth Can be hardly reduced in tensile strength. This is considered to be due to the following reasons.

  It is considered that the bleeding of the image occurs because the landed ink oozes out from the edge of the image to be formed, so that the sublimable dye also diffuses and fixes beyond the edge of the image. In the direct sublimation printing method, ink is directly landed on a cloth without using an intermediate transfer medium, so that the amount of ink that lands in an image forming area increases, and image bleeding is more likely to occur than in the normal sublimation printing method.

  It is considered that the tensile strength of the fabric is caused by heating the fabric, whereby the fibers are deteriorated by heat. In the sublimation printing method, the fabric is heated to a higher temperature than the normal printing method, so that the fibers are deteriorated by heat and the tensile strength of the fabric is liable to decrease. In particular, in direct sublimation printing, since the amount of ink that lands on the image forming area increases, the heating time required to sublimate, diffuse and fix the sublimable dye is longer, and the tensile strength of the fabric is higher. Easy to fall.

  With respect to these phenomena, by performing printing using the special color ink, the amount of the ink that lands on the image forming site can be made smaller than when printing is performed using only the process color ink. Therefore, the amount of ink that oozes out from the edge of the image to be formed is also reduced, and bleeding of the image is suppressed. Further, the heating time required for sublimating and diffusing and fixing the sublimable dye can be reduced, so that a decrease in tensile strength can be suppressed.

  Specifically, the printing method of the present invention includes a step of discharging the droplets of the plurality of types of ink from a recording head and landing them on the image forming portions of the fabric (hereinafter, also simply referred to as a “landing step”). ), And heating the image forming site where the plurality of types of ink droplets have landed to a temperature at which all of the sublimable dyes contained in the plurality of types of ink sublimate (hereinafter simply referred to as “heating”). Step ”). The textile printing method of the present invention optionally includes a step of washing the fabric after the heating step (hereinafter, also simply referred to as “washing step”), and further optionally, a step of drying the fabric after the washing step (hereinafter simply referred to as “washing step”). "Drying step"). The printing method of the present invention does not use a sizing agent, and thus does not include a washing step for removing the sizing agent.

1. Landing Step In the landing step, a plurality of types of ink droplets are respectively ejected from the recording head toward the fabric. The ejected droplet lands on an image forming portion of the fabric to form an image before color development. For example, while the cloth is relatively moved with respect to a head carriage on which a recording head is mounted, the plurality of types of ink droplets are ejected from the recording head, and the droplets are landed on the image forming portion, so that the ink before coloring is formed. An image can be formed. The plurality of types of ink droplets may be ejected at a time shifted from each other or simultaneously.

  The plurality of types of ink include a process color ink and a special color ink. As the process color ink, yellow ink, magenta ink, cyan ink, or black ink can be used. As the special color ink, for example, red ink, orange ink, green ink, blue ink, pink ink or violet ink can be used. As the special color ink, only one color ink may be used, or two or more inks exhibiting mutually different colors may be used.

  At least a part of the droplet of the process color ink and at least a part of the droplet of the special color ink land on the same area in the image forming portion. As a result, the color forming a part of the image to be formed is colored by the combination of the dye contained in the process color ink and the dye contained in the special color ink.

  From the viewpoint of suppressing bleeding of the image before coloring, the cloth may be heated as necessary when performing the landing step.

  According to the textile printing method of the present invention, it is possible to reduce the amount of ink droplets that land on an image forming site. From the viewpoint of sufficiently developing the color of the image and sufficiently suppressing the occurrence of the bleeding and the decrease in the tensile strength by reducing the amount of the ink, the plurality of types of the plurality of types per mass (g) of the cloth at the image forming portion are used. The maximum landing amount (ml) of each ink constituting the ink is preferably 0.033 ml / g or more and 0.100 ml / g or less. By setting the maximum landing amount to 0.033 ml / g or more, a more sufficiently colored image can be obtained. By setting the maximum landing amount to 0.100 ml / g or less, the landing amount of the ink becomes smaller with respect to the density of the fabric, so that the image is less likely to bleed and the tensile strength is further reduced. It becomes difficult. From the above viewpoint, the maximum landing amount is more preferably 0.040 ml / g or more and 0.090 ml / g or less.

  In the landing step, since the ink droplets land directly on the image forming site, the printing method of the present invention does not require image formation on the intermediate transfer medium and transfer of the image from the intermediate transfer medium to the image forming site. Therefore, the printing method of the present invention can perform printing more easily and at lower cost than the conventional sublimation printing method.

1-1. Ink The above plurality of types of inks are all inks containing a sublimable dye, a dispersant, and water. This ink can be used as an aqueous ink for inkjet printing for direct sublimation printing.

1-1-1. Sublimable Dye The sublimable dye may be any dye that can be sublimated by heating and can be diffused and fixed between the fibers constituting the fabric. The sublimable dye is preferably a disperse dye which is insoluble or hardly soluble in water but can be dispersed in water using a dispersant. The sublimable dye may be an azoic dye or a cationic dye as long as it sublimates by being heated. As the sublimable dye, only one kind may be contained in the ink, or two or more kinds may be contained in combination.

  Examples of sublimable dyes that are disperse dyes include C.I. I. Disperse Yellow (hereinafter, also simply referred to as “DY”) 1, DY3, DY4, DY5, DY7, DY8, DY31, DY33, DY39, DY42, DY54, DY60, DY61, DY64, DY83, and DY124. . I. Disperse Red (hereinafter, also simply referred to as “DR”) 1, DR4, DR5, DR7, DR11, DR12, DR13, DR15, DR17, DR31, DR32, DR33, DR34, DR35, DR36, DR52, DR54, DR55, DR56, Magenta including DR58, DR60, DR72, DR73, DR76, DR80, DR84, DR88, DR91, DR92, DR93, DR99, DR111, DR113, DR135, DR204, DR205, DR206, DR207, DR224, DR225, DR227, DR239, DR240 Dyes; C.I. I. Disperse Blue (hereinafter, also simply referred to as “DB”) 20, DB26, DB54, DB55, DB56, DB58, DB60, DB61, DB62, DB64, DB72, DB79, DB81, DB85, DB87, DB90, DB91, DB92, DB94, DB97, DB98, DB99, DB103, DB104, DB105, DB106, DB108, DB128, DB148, DB149, DB176, DB186, DB187, DB193, DB194, DB195, DB197, DB201, DB205, DB207, DB211, DB212, DB213, DB214, DB215, DB216, DB217, DB218, DB219, DB220, DB221, DB222, DB223, DB224, DB225 Cyan dye comprising DB226 and DB 227, C. I. An orange dye containing Disperse Orange (hereinafter, also simply referred to as “DO”) 25; I. A green dye containing Disperse Green (hereinafter, also referred to simply as “DG”) 9; I. Violet dyes including Disperse Violet (hereinafter, also simply referred to as “DV”) 60 are included.

  By adjusting the combination and amount of these sublimable dyes, process color inks and various special color inks exhibiting a desired color tone can be prepared.

  For example, by adjusting the combination and amount of the sublimable dye, the special color ink can be a red ink, an orange ink, a green ink, a blue ink, a pink ink or a violet ink.

  From the viewpoint of improving color development, the content of the sublimable dye is preferably from 0.2% by mass to 12% by mass with respect to the total mass of the ink. From the viewpoint of making the color tone produced by the ink of the present invention clearer, the content of the coloring material is more preferably 0.5% by mass or more and 8% by mass or less based on the total mass of the ink.

1-1-2. Dispersant Any dispersant can be used as long as it can enhance the dispersibility of the sublimable dye and suppress the generation of bubbles in the ink, the gelation of the ink, and the increase in the viscosity of the ink.

  Examples of dispersants include formalin condensate of creosote oil sodium sulfonate, formalin condensate of sodium cresol sulfonate and sodium 2-naphthol-6-sulfonate, formalin condensate of sodium cresol sulfonate, sodium phenol sulfonate A formalin condensate of sodium β-naphtholsulfonate, a formalin condensate including sodium β-napthalin sulfonate and sodium β-naphthol sulfonate, an alkylene oxide including ethylene oxide and propylene oxide, a fatty alcohol, a fatty amine, Alkylatable compounds including fatty acids, phenols, alkylphenols and carboxylamines, lignin sulfonates, sodium paraffin sulfonates, α-olefins Copolymer of water maleic acid, as well as known comb block polymers.

  Examples of comb block polymers include DISPERBYK-190, DISPERBYK-194N, DISPERBYK-2010, DISPERBYK-2015, and BYK-154, and Big Chemie ("DISPERBYK" and "BYK" are registered trademarks of the same company).

  From the viewpoint of securing high ejection stability from the recording head, and making it more difficult to cause fading of the image due to sublimation of the sublimable dye after printing, the dispersant has both a hydrophobic part and a hydrophilic part, Further, it is preferable that a total of 5 to 20 ethylene oxide groups or propylene oxide groups are contained in the molecule as the hydrophilic site. From the above viewpoint, the number of ethylene oxide groups or propylene oxide groups is more preferably 8 or more and 16 or less. Examples of the hydrophilic site include an alkyl group, an alkylene group, an arylene group, an acyl group, an amino group, and an aryl group which may be substituted. Examples of such dispersants include DISPERBYK-183, DISPERBYK-187 and DISPERBYK-192, BYK Chemie, and SOLSPERSE41000, Nippon Lubrizol Corporation.

  The amount of the dispersant can be 30 parts by mass or more and 70 parts by mass or less when the total mass of the sublimable dye is 100 parts by mass. By setting the amount of the dispersant to 30 parts by mass or more, the dispersibility of the sublimable dye can be further improved, and the storage stability of the ink can be improved. By setting the amount of the dispersant to 70 parts by mass or less, an excessive increase in the viscosity of the ink due to the dispersant can be suppressed, and the ejection stability of the ink can be improved.

1-1-3. Other components Ink, in addition to the above, organic solvents, surfactants, preservatives, fungicides, or dyes other than sublimable dyes, as long as they do not enlarge the bleeding of the image and do not lower the tensile strength of the fabric. May be included.

  Examples of the water-soluble organic solvent include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, alcohols including sec-butanol and t-butanol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, Propylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, the compound represented by the formula (1), other glycerin, hexanetriol, thiodiglycol, 1,2-butanediol, 1,2-pentanediol, Alcohols including 1,2-hexanediol and 1,2-heptanediol, ethanolamine, diethanolamine, triethanolamine, N-methyldiamine Amines, including formaldehyde, N, N-amine, including tanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine and tetramethylpropylenediamine Amide including dimethylformamide and N, N-dimethylacetamide, heterocyclic compound including 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone and 1,3-dimethyl-2-imidazolidinone, dimethyl Sulfoxides, including sulfoxides, and alkyl ethers of diethylene glycol, alkyl ethers of triethylene glycol and dipropylene glycol Include glycol ethers containing alkyl ether Le.

In the formula (1), R ₁₁ independently represents an ethylene glycol group or a propylene glycol group, x, y and z each independently represent a positive integer, and x + y + z = 3 to 30.

  The amount of the water-soluble organic solvent can be 20% by mass or more and less than 70% by mass based on the total mass of the ink. By setting the amount of the water-soluble organic solvent to 20% by mass or more based on the total mass of the ink, the dispersibility of the sublimable dye in the ink is further improved, and the ejection property is further improved. When the amount of the water-soluble organic solvent is less than 70% by mass based on the total mass of the ink, the ink of the present invention has good drying properties even when a water-soluble organic solvent is contained.

  Examples of the surfactant include a cationic surfactant, an anionic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  Examples of the cationic surfactant include an aliphatic amine salt, an aliphatic quaternary ammonium salt, a benzalkonium salt, a benzethonium chloride, a pyridinium salt, and an imidazolinium salt.

  Examples of the anionic surfactant include fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acylglutamate, alkyl ether carboxylate, Acylated peptide, alkyl sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, high grade Alcohol sulfate, secondary higher alcohol sulfate, alkyl ether sulfate, secondary higher alcohol ethoxy sulfate, polyoxyethylene alkyl phenyl ether sulfate, monoglyculfate, fatty acid alkylolamide sulfate, alkyl ether Phosphate S Includes tellurates and alkyl phosphate esters.

  Examples of the amphoteric surfactant include carboxybetaine type, sulfobetaine type, aminocarboxylate and imidazolinium betaine.

  Examples of the nonionic surfactant include a silicone-based surfactant and a fluorine-based surfactant.

  Examples of the preservatives or fungicides include aromatic halogen compounds, methylene dithiocyanate, halogen-containing sulfur compounds, 1,2-benzisothiazolin-3-one (for example, Proxel GXL (manufactured by Arch Chemical Co., (Registered trademark of the company)).

1-1-4. From the viewpoint of further improving the ejection properties of the ink, the viscosity of the ink at 25 ° C. is preferably from 1 mPa · s to 40 mPa · s, more preferably from 5 mPa · s to 40 mPa · s, More preferably, it is 5 mPa · s or more and 20 mPa · s or less. The viscosity of the ink can be measured at 25 ° C. and 20 rpm with an E-type viscometer (for example, V-25, manufactured by Toki Sangyo Co., Ltd.).

  The surface tension of the ink at 25 ° C. is preferably from 25 mN / m to 50 mN / m. When the surface tension is 25 mN / m or more, blurring of an image is less likely to occur. When the surface tension is 50 mN / m or less, the ink of the present invention is more easily permeated into the fabric. The surface tension of the ink can be measured by, for example, CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.

1-2. Fabric The fabric may be any fabric as long as at least the image forming site contains polyester fibers. The image forming portion may be formed only of the polyester fiber, or may be formed by mixing the polyester fiber with another fiber. Examples of fabrics formed by mixing polyester fibers with other fibers include polyesters in which polyurethane blended fibers are blended by 1% by weight or more, and polyesters in which polylactic acid fibers are blended by 1% by weight or more.

  In the conventional direct sublimation printing method, a fabric having a shrinkage rate of 5.0% or more obtained based on a dry heat ironing method (an iron temperature is set to 140 ° C.) described in JIS L 1057 causes shrinkage due to heat. Therefore, it was not suitable for printing by direct sublimation printing. However, according to the method of the present invention, the shrinkage problem of the image forming portion is not less than 5.0%, preferably not less than 6.0%, more preferably not less than 7.0%. Printing can be performed by the direct sublimation printing method without occurrence.

  The shrinkage rate obtained based on the dry heat ironing method described in JIS L 1057 is 150 mm longer than the ironing surface on the cloth while applying a pressure of 2.9 kPa at an iron temperature of 140 ° C. It means the shrinkage of the fabric when the distance is reciprocated three times at a speed of 100 mm / s.

  From the viewpoint of facilitating the diffusion and fixation of the sublimable dye between the fibers, the image forming site does not substantially contain a sizing agent. The sizing agent refers to a component applied to the fabric as a pre-treatment agent before the ink lands in ink-jet printing. Examples of sizing agents include natural water-soluble polymers and synthetic water-soluble polymers. Examples of natural water-soluble polymers include starches including corn and wheat, cellulose derivatives including carboxymethylcellulose, methylcellulose and hydroxyethylcellulose, sodium alginate, polysaccharides including guar gum, tamarind gum, locust bean gum and gum arabic, And proteinaceous substances including gelatin, casein and keratin. Examples of the synthetic water-soluble polymer include polyvinyl alcohol, polyvinyl pyrrolidone, and an acrylic acid-based polymer.

  The fact that the paste is not substantially contained means that the pre-processing is not performed on the image forming portion. Unless the pretreatment is performed, the image forming site contains, for example, 0.1% by mass or less of the natural water-soluble polymer or the synthetic water-soluble polymer that inevitably adheres to the weight of the fabric. You may.

  According to the textile printing method of the present invention, bleeding of an image can be suppressed without performing pre-processing, so that a pre-processing step is unnecessary. Further, according to the printing method of the present invention, since the image forming portion does not substantially contain the sizing agent, a washing step for removing the sizing agent after heating is unnecessary. Therefore, the printing method of the present invention can perform printing more easily and at lower cost than the conventional inkjet printing method.

2. Heating Step In the heating step, the image forming portion of the cloth on which the image before coloring is formed is heated to a temperature at which any of the sublimable dyes contained in the plurality of types of inks sublimates. Specifically, the image forming portion is heated to a temperature higher than the sublimation temperature of the sublimable dye having the highest sublimation temperature among the sublimable dyes contained in the plurality of types of inks. When the image forming site is heated, the sublimable dye sublimates and diffuses and fixes between the fibers to form an image.

  Many of the sublimable dyes have a sublimation temperature between 145 and 230C. From the viewpoint of sufficiently sublimating the sublimable dye and further suppressing deterioration of the fabric due to heat, the fabric is preferably heated to 150 ° C or more and 220 ° C or less, and is heated to 180 ° C or more and 210 ° C or less. Is more preferable. The heating time can be determined from the viewpoint of sufficiently diffusing and fixing the sublimable dye, and can be, for example, from 10 seconds to 300 seconds. Preferably, it is 15 seconds or more and 180 seconds or less.

  The heating method can be appropriately selected from the methods in which the temperature of the fabric can be set to the above-mentioned temperature. Examples of such methods include heating with a heater and heating with infrared. From the viewpoint of sublimating the sublimable dye more sufficiently, it is preferable to heat the cloth without using steam. In addition, from the viewpoint of sublimating the sublimable dye more sufficiently, pressure may be applied to the cloth simultaneously with heating.

3. Washing step The washing step is a step of washing the fabric after the color forming step to remove dyes that could not be fixed to the fibers of the fabric. In this step, the fabric may be washed with water, or the fabric may be washed with a soaping solution as long as the dye can be removed. Examples of the soaping liquid include a mixture of caustic soda, surfactant and hydrosulfite.

4. Drying Step The drying step is a step of drying the washed fabric. Examples of drying methods include non-mechanical drying by squeezing or drying the washed fabric, and mechanical drying by a dryer (heat roll or iron).

  Hereinafter, the present invention will be described in more detail with reference to Examples, but these descriptions should not be construed as limiting the scope of the present invention. In the following examples, the abbreviations of the components used for preparing the ink are shown in parentheses.

[Preparation of ink]
The components shown in Table 1 were mixed in the amounts shown in Table 1, and dispersed with a paint shaker together with beads of 0.03 mm, and the inks Y, M, C, K, R, O, G, B, P and V were prepared. Was prepared. The amount of ion-exchanged water was adjusted so that the total of each component was 100% by mass. In Table 1, the numerical value of each component represents the amount (unit: mass%) of each component in the ink.

  The inks Y, M, C, K, R, O, G, B, P, and V are yellow ink, magenta ink, cyan ink, black ink, red ink, orange ink, green ink, blue ink, and pink ink, respectively. And violet ink.

The above ink was put into an ink jet head (Konica Minolta head # 204), and all colors of the prepared ink were applied on a cloth made of PE / PU mixed fiber (PU ratio: 5% by mass) at a frequency of 18 kHz. The maximum discharge amount for each color ink was set at 9 ml / m ² to form a high-definition color digital standard image (XYZ / SCID) “N3 Fruit Basket” (founded by the Japan Planning Association, 1995). After the recorded fabric was dried, the fabric was heated to 205 ° C. for 60 seconds to produce Sample 101.

  Samples 102 to 107 were prepared in the same manner except that the combination of inks used for recording images, the maximum ejection amount for each color ink, the type of fabric, the heating temperature, and the heating time were changed as shown in Table 2. , Samples 201 to 206 and Samples 301 to 304 were produced. In the column of “Fabric type” in Table 2, “PE” indicates that the image forming site contains polyester fiber, “PU” indicates that the image forming site contains polyurethane fiber, and “PL” indicates the image forming site. Indicates that polylactic acid fibers are contained, and the numerical value in parentheses indicates the content (unit: mass%) of fibers other than polyester fibers.

[Evaluation of bleeding]
Each sample was visually checked and bleeding was evaluated according to the following criteria.
◎ No bleeding is observed ○ Bleeding is observed but not bothersome △ Little bleeding is observed × Many bleeding is observed

[Evaluation of reduction rate of tensile strength]
Each of the fabrics shown in Table 2 before direct sublimation printing was subjected to a tensile test of the fabric by the method described in JIS 1068, and the tensile strength of the fabric (hereinafter, also simply referred to as “strength before dyeing”) was determined. For each of the samples described in Table 2 after direct sublimation printing, a tensile test of the fabric is similarly performed by the method described in JIS 1068 to determine the tensile strength of the fabric (hereinafter, also simply referred to as “strength after dyeing”). Was.

According to the following formula, the reduction rate of the tensile strength (hereinafter, also simply referred to as “reduction rate”) was calculated.
Reduction rate = 100− (strength after dyeing / strength before dyeing) × 100
The rate of decrease in tensile strength was evaluated according to the following criteria.
: 95% or more △: 85% to 95%
×: less than 85%

[Measurement of staining concentration]
The maximum absorbance of each sample was measured with a color difference meter (manufactured by X-Rite).

  Table 3 shows the evaluation or measurement results of each sample.

  When an image was formed without using a special color ink, the amount of ink discharged per color was large, so that much bleeding occurred (comparison between Samples 101, 102 and 104 and Sample 103, and between Samples 105 and 107 and Sample 106). Comparison with.). By increasing the number of types of special color inks from two to more, bleeding was more unlikely to occur (by comparison between Samples 101 and 102 and Sample 104, and between Sample 105 and Sample 107).

  By setting the maximum ejection amount of each color ink to 0.033 or more and 0.100 or less of the weight of the fabric, an image having a sufficient dyeing density can be obtained, and bleeding is further suppressed and tensile strength is hardly reduced. (Based on a comparison between Samples 202 to 205 and Samples 201 and 206).

  By setting the maximum landing amount (ml) of each ink per mass (g) of the fabric to 0.033 ml / g or more and 0.100 ml / g or less, an image can be sufficiently colored, and bleeding can be generated and tensile It was possible to sufficiently suppress the reduction in strength (by comparison between Samples 202 to 205 and Samples 201 and 206).

  In the fabric having a shrinkage ratio of 5.0% or more due to ironing at 140 ° C., a decrease in tensile strength was suppressed by the method of the present invention. However, when an image was formed by a conventional direct sublimation printing method, the tensile strength increased. (Comparison between Samples 101, 102 and 104 and Sample 103).

  When an image was formed on a fabric further containing a polyurethane fiber or a polylactic acid fiber, a decrease in tensile strength was suppressed in the method of the present invention, but when an image was formed by a conventional direct sublimation printing method, the tensile strength was greatly reduced. (Comparison between Samples 101, 102 and 104 and Sample 103.)

  In these examples, no sizing agent was used. Fabric printing by the direct sublimation printing method was possible without a washing process.

  According to the printing method of the present invention, even in the direct sublimation printing method, bleeding of an image and reduction in tensile strength of a fabric are suppressed. Therefore, the present invention is expected to contribute to the development of the direct sublimation printing method.

Claims (4)

Droplets of a plurality of types of inks containing a sublimable dye, a dispersant, and water are respectively discharged from a recording head for ink jet, and a step of landing on an image forming portion including polyester fibers of a fabric, respectively.
Heating the image forming site of the fabric on which the plurality of types of ink droplets have landed to a temperature at which any of the sublimable dyes contained in the plurality of types of inks sublimates. At
The ink includes one or more process color inks selected from the group consisting of yellow ink, magenta ink, cyan ink and black ink, and special color inks,
In the landing step, the maximum landing amount (ml) of each of the plurality of types of ink per mass (g) of the cloth at the image forming site is 0 . 100 ml / g or less,
At least a portion of the process color ink droplets and at least a portion of the special color ink droplets land on the same region in the image forming portion,
The shrinkage ratio of the image forming portion, which was determined based on the dry heat ironing method described in JIS L 1057 at an iron temperature of 140 ° C., was 5.0% or more,
The method, wherein the image forming site is substantially free of a glue.   The method of claim 1, wherein the special color ink is one or more inks selected from the group consisting of red ink, orange ink, green ink, blue ink, pink ink, and violet ink.   3. The method according to claim 1, wherein in the heating step, a heating time is 15 seconds or more and 180 seconds or less. 4. The method according to any one of claims 1 to 3 , wherein the image forming part further comprises a polyurethane fiber or a polylactic acid fiber.