JP5338048B2 - Ink for inkjet printing and inkjet printing method using the same - Google Patents

Description

  The present invention relates to an ink for ink jet textile printing and a recording method for ink jet textile printing, and more particularly to an ink for ink jet textile printing and an ink jet textile printing method used for textile printing excellent in light emission at high speed driving and light emission after storage over time. About.

  In recent years, in the field of textile printing, there has been a demand for an ink jet textile printing method that does not require a plate making process in order to shorten the delivery time and cope with small-lot and multi-product production. In the ink jet textile printing method, ink is often stored and used for a long period of time, and it is important to improve its storage stability. At the same time, emission stability is also important, and it is well known that impurities cause various problems in ink-jet ink. For example, filterability deteriorates due to many impurities, and continuous emission In some cases, the light emission may be deteriorated, such as bending or missing. Furthermore, in recent years, the demand for using products for full-scale production by inkjet has been increasing, and the demand for improving the printing speed is increasing year by year.

  For this reason, it is conventionally known to purify dyes. For example, it is described that a dye is purified and used to remove a polyvalent metal salt (see, for example, Patent Documents 1 and 2). Further, it is described that the amount of chlorine ions and sulfate ions remaining is suppressed (see, for example, Patent Document 3). Moreover, there are some descriptions as examples of dye purification using activated carbon (see, for example, Patent Documents 4 and 5). According to these reports, the invention has been made from the viewpoint of removing impurities during production.

  In addition, from the viewpoint of reducing impurities in the ink as much as possible, it is described that the stability of emission is improved by defining the total volume of particles in the ink (see, for example, Patent Document 6).

However, inkjet inks are required to be stored for a long period of time from manufacture to distribution and consumed, and are effective for various problems caused by degradation products such as dye degradation products. It was not something to demonstrate. Furthermore, the problems related to emission that occur at the time of increasing the printing speed in recent years have not yet been recognized as a problem, and of course have not exhibited sufficient effects.
Japanese Patent Laid-Open No. 05-5053 Japanese Patent Laid-Open No. 2004-295472 JP 05-186727 A Japanese Patent Application Laid-Open No. 11-19404 JP 2005-29610 A Japanese Patent No. 3027982

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an ink for ink-jet printing and an ink-jet printing method that are excellent in light-emitting properties, in particular, the light-emitting properties when the head is driven at high speed and the light-emitting properties when stored over time. It is to provide.

  The above object of the present invention can be achieved by the following configuration.

1. In the ink for inkjet printing containing at least water, a water-soluble dye purified with activated carbon and a water-soluble organic solvent, the content of the water-soluble dye is 5 to 20% by mass, and the activated carbon fine particles having a particle size of 1 to 30 nm Is contained in the ink for inkjet printing in an amount of 5 × 10 ² to 80 × 10 ³ / ml.

2. ^2. The ink for inkjet printing according to 1 above, wherein the content of the activated carbon fine particles is 5 × 10 ^{2 to} 20 × 10 ³ particles / ml.

3. 3. The ink for ink-jet textile printing according to 1 or 2 above, wherein a degassing step using a hollow fiber membrane is used after ink preparation.

4). 4. The ink for inkjet printing according to 3 above, wherein the deaeration step includes a deaeration step using a hollow fiber membrane and an ultrasonic treatment apparatus.

5). 5. An ink jet textile printing method, wherein the ink for ink jet textile printing according to any one of 1 to 4 is printed using a print head having a driving frequency of 10 kHz to 20 kHz.

6). 6. The ink-jet printing method as described in 5 above, wherein the print head ejects ink using a piezo drive system and performs printing.

  According to the present invention, it is possible to provide an ink for ink-jet printing and an ink-jet printing method that are excellent in light-emitting properties, in particular, the light-emitting properties when the head is driven at a high speed and the light-emitting properties when stored over time.

  The present invention will be described in more detail.

  That is, as a result of intensive studies, the present inventors have found an ink for ink jet textile printing (hereinafter, also simply referred to as ink) that is excellent in light emission properties, in particular, light emission properties when the head is driven at high speed and light emission properties after storage over time.

  There are various types of ink-jet recording methods, but the on-demand type recording methods that have become mainstream in recent years are the so-called piezo method (piezoelectric element method) using a piezo element and the thermal jet method (bubble jet (registered trademark)). being classified. The piezo method repeatedly pressurizes and depressurizes a large number of times during ink discharge, so micro bubbles are likely to be generated due to cavitation, causing dot dropout and landing position misalignment during ink discharge and degrading print quality such as graininess. ing. In general, cavitation is a physical phenomenon in which a liquid evaporates into bubbles when the pressure of the liquid at a certain temperature is lower than the vapor pressure determined by the temperature.

  Therefore, the ink used is usually deaerated and the amount of gas contained in the ink is reduced as much as possible to prevent the generation of bubbles during ejection. Although it is recognized that cavitation does not occur by performing deaeration treatment in dissolved inks such as those using water-soluble dyes, the present inventors also have a head driven at high speed even in dissolved inks. It has been found that there is an influence of cavitation in the phenomenon in which ejection failure occurs with ink after being stored by ink and after being stored over time. Furthermore, when fine particles that should not be present in the dissolution system are present in an amount other than the range where the fine particles are present, particularly when the light is emitted using a head having a high driving frequency, if the emission is continued for a long time, all nozzles Are seen to be not emitted almost simultaneously.

  As described above, the present inventors have found that by controlling the number of fine particles to an appropriate number, the effect of excellent ink emission properties and emission properties after storage over time is exhibited.

The ink for inkjet textile printing of the present invention contains at least water, a water-soluble dye, and a water-soluble organic solvent in the ink, and 5 × 10 ² to 80 × 10 ³ fine particles having an average particle diameter of 1 to 30 nm are contained in the ink. / Ml is preferably included. Furthermore, it is particularly preferable that the fine particles in the ink are 5 × 10 ^{2 to} 20 × 10 ³ particles / ml. When the number of fine particles in the ink is larger than this range, cavitation occurs due to the influence of bubble nuclei attached to the fine particles, resulting in emission failure. In particular, this decrease is significant when ink is ejected at a high-speed drive with a head drive frequency of 10 kHz or more. Further, when the number of fine particles is less than this range, an emission defect is caused. In particular, the ink ejection stability is significantly reduced after the ink is stored over time. Although no clear mechanism has been confirmed for the cause, it is estimated as follows.

  It has been confirmed that many of the fine particles in the ink are activated carbon brought from the purified dye. By applying a filter to the final process at the time of ink preparation, most of the solids such as brought-in activated carbon and undissolved dye are removed, but a small amount remains in the ink. In the case of the remaining amount exceeding the range of the present invention, cavitation occurs due to the bubble nuclei adhering to the fine particles as described above. Outgoing properties are impaired by the decomposition product. Therefore, it is presumed that the decomposition product is adsorbed by the amount of the activated carbon remaining in the ink in the lower limit of the range of the present invention.

  In commercially available printer inks intended for printing on ordinary paper media, the dye concentration is usually around 2 to 4%, and the number of fine particles brought in from the dye does not need to be considered in particular. For inks used for such textile printing, when the dye concentration is very high and used in the range of 5% to 20%, there are many brought-in fine particles, and the amount is controlled within the range of the present invention. Thus, stable light emission can be ensured.

  Various methods are conceivable as means for controlling the fine particles, but a typical method is a fine particle removal method by filtration. Furthermore, the effect can be obtained by controlling the filter diameter, the filter material, the liquid passing speed at the time of filtering, and the like within the scope of the present invention.

  The method for measuring the amount of fine particles can be selected as appropriate, but measurement using a Coulter counter device is preferred. Since the measurement principle is a well-known method, it is omitted, but the aperture size must be used in accordance with the particle size. In the measurement of the amount of fine particles in the present invention, it is known that a more preferable range can be detected from the measurement result when an aperture diameter of 50 μm is used, but it is not limited to the conditions. As a measuring device, measurement was performed using a precision particle size distribution measuring device Multisizer 3 manufactured by Beckman Coulter.

  Activated carbon in the present invention is strongly adsorbent, mostly carbonaceous charcoal, is amorphous carbon in the form of powder, granules or pellets, and has countless fine pores, so it is extremely per unit volume. It has the characteristic of having a large surface area. In the present invention, it is possible to use various activated carbons, such as activated carbon for solvent recovery, activated carbon for automobile canisters, activated carbon for water treatment, activated carbon for chemical liquid decolorization, and the like. Further, the shape is preferably powdery, and the production method is preferably steam charcoal.

  Methods for degassing dissolved gas from the ink are roughly divided into a method of degassing by a physical method such as boiling or decompression, and a chemical method of mixing an absorbent into the ink.

  In the present invention, degassing can be performed by any means. In particular, the method of permeating and removing dissolved gas in the ink by passing the ink through the gas-permeable hollow fiber membrane and reducing the pressure on the outer surface side of the hollow fiber membrane has an adverse effect on the physical properties of the ink. This is preferable because the dissolved gas in the ink can be efficiently removed without giving.

  As the hollow fiber membrane deaeration module used in the present invention, a commercially available one can be used. For example, Mitsubishi Rayon Co., Ltd. MHF series, Dainippon Ink & Chemicals, Inc. SEPAREL series, etc. are mentioned. The deaeration process using the hollow fiber membrane module is performed, for example, by supplying ink from the ink supply port at the end of the module to the inside of the hollow fiber membrane and sucking it from the gas deaeration port on the side wall of the module. While the pressure is reduced as described below, the dissolved gas in the ink that has passed through the membrane is discharged, and the deaerated ink exits from the ink outlet at the other end of the module. In the deaeration process using the hollow fiber membrane module, ink can be supplied to the outside of the hollow fiber membrane and the inside can be decompressed.

  In the present invention, it is particularly desirable to remove minute bubble nuclei attached to the surface of the particles by passing an ultrasonic treatment device during the deaeration process. In particular, it is particularly preferable for preventing cavitation that occurs when the head is driven at high speed. Although the ultrasonic processing apparatus used for this invention is not specifically limited, Nippon Seiki Seisakusho Co., Ltd. circulation type RUS-600T (frequency 20kHz, maximum output 600W), Branson Co., Ltd. continuous type model 900 type (frequency 20kHz, maximum) Output 900W) can be used. The ultrasonic treatment conditions include frequency, amplitude, and irradiation energy. If the frequency is higher than 30 KHz, the aggregating action becomes strong and the dispersibility deteriorates. Since the cavitation pressure is higher as the amplitude is larger, it can be performed in a general amplitude range of 20 to 60 μm. The irradiation energy is 1 * 104 to 1 * 105 J, preferably 2 * 104 to 8 * 104 J. If the irradiation energy is too low, the ability to remove bubble nuclei is insufficient, and if it is too high, the temperature rises and causes aggregation. In addition, ultrasonic deaeration may be performed after the deaeration treatment with the hollow fiber membrane is once stored in a kettle or the like, but it is preferable to perform the deaeration continuously.

  The dissolved oxygen concentration in the ink is preferably 2 ppm or less in terms of emission stability, and more preferably 1 ppm or less.

  The dissolved oxygen concentration in the ink can be measured by the Ostwald method (experimental chemistry course 1 basic operation [I], page 241, 1975, Maruzen), the mass spectrum method, the galvanic cell type, the polarographic type, etc. It can be measured with a simple oxygen concentration meter or colorimetric analysis. As a commercially available dissolved oxygen concentration meter (Toa Denpa Kogyo Co., Ltd. DO-30A type) can be mentioned.

  Examples of the colorant in the present invention include water-soluble dyes such as reactive dyes, acid dyes, and direct dyes. In the present invention, any colorant can be used, but when the fabric is a material such as cotton or silk, an ink composed of a reactive dye and an aqueous medium is preferably used. Nylon, wool, silk, rayon, etc. In the case of these materials, an ink composed of an acid dye, a direct dye and the like and an aqueous medium is preferably used. When the fabric is a polyester material, an ink composed of a dispersible dye and an aqueous medium is preferably used.

  Specific compounds of preferred acid dyes for the present invention are shown below. However, it is not limited to the compound illustrated to these.

Preferred acid dyes for the present invention are:
C. I. Acid Yellow 1, 3, 6, 11, 17, 18, 19, 23, 25, 36, 38, 40, 40: 1, 42, 44, 49, 59, 59: 1, 61, 65, 67, 72, 73 79,99,104,159,169,176,184,193,200,204,207,215,219219: 1,220,230,232,235,241,242,246,
C. I. Acid Orange 3, 7, 8, 10, 19, 22, 24, 51, 51S, 56, 67, 74, 80, 86, 87, 88, 89, 94, 95, 107, 108, 116, 122, 127, 140 , 142, 144, 149, 152, 156, 162, 166, 168,
C. I. Acid Red1,6,8,9,13,18,27,35,37,52,54,57,73,82,88,97,97: 1,106,111,114,118,119,127,131 , 138, 143, 145, 151, 183, 195, 198, 211, 215, 217, 225, 226, 249, 251, 254, 256, 257, 260, 261, 265, 266, 274, 276, 277, 289 , 296, 299, 315, 318, 336, 337, 357, 359, 361, 362, 364, 366, 399, 407, 415, 447
C. I. Acid Violet 17, 19, 21, 42, 43, 47, 48, 49, 54, 66, 78, 90, 97, 102, 109, 126,
C. I. Acid Blue1,7,9,15,23,25,40,61: 1,62,72,74,80,83,90,92,103,104,112,113,114,120,127,127: 1 128,129,138,140,142,156,158,171,182,185,193,199,201,203,204,205,207,209,220,221,224,225,229,230,239 , 258, 260, 264, 277: 1,278, 279, 280, 284, 290, 296, 298, 300, 317, 324, 333, 335, 338, 342, 350,
C. I. Acid Green 9, 12, 16, 19, 20, 25, 27, 28, 40, 43, 56, 73, 81, 84, 104, 108, 109,
C. I. Acid Brown 2, 4, 13, 14, 19, 28, 44, 123, 224, 226, 227, 248, 282, 283, 289, 294, 297, 298, 301, 355, 357, 413,
C. I. Acid Black 1, 2, 3, 24, 24: 1, 26, 31, 50, 52, 52: 1, 58, 60, 63, 63S, 107, 109, 112, 119, 132, 140, 155, 172, 187 , 188, 194, 207, 222
Specific compounds of reactive dyes preferred in the present invention are shown below. However, it is not limited to the compound illustrated to these.

C. I. Reactive Yellow 2, 3, 7, 15, 17, 18, 22, 23, 24, 25, 27, 37, 39, 42, 57, 69, 76, 81, 84, 85, 86, 87, 92, 95, 102 , 105, 111, 125, 135, 136, 137, 142, 143, 145, 151, 160
161, 165, 167, 168, 175, 176,
C. I. Reactive Orange 1, 4, 5, 7, 11, 12, 13, 15, 16, 20, 30, 35, 56, 64, 67, 69, 70, 72, 74, 82, 84, 86, 87, 91, 92 , 93, 95, 107,
C. I. Reactive Red 2, 3, 3: 1, 5, 8, 11, 21, 22, 23, 24, 28, 29, 31, 33, 35, 43, 45, 49, 55, 56, 58, 65, 66, 78 83, 84, 106, 111, 112, 113, 114, 116, 120, 123, 124, 128, 130, 136, 141, 147, 158, 159, 171, 174, 180, 183, 184, 187, 190 , 193, 194, 195, 198, 218, 220, 222, 223, 226, 228, 235,
C. I. Reactive Violet 1, 2, 4, 5, 6, 22, 23, 33, 36, 38,
C. I. Reactive Blue 2, 3, 4, 7, 13, 14, 15, 19, 21, 25, 27, 28, 29, 38, 39, 41, 49, 50, 52, 63, 69, 71, 72, 77, 79 89, 104, 109, 112, 113, 114, 116, 119, 120, 122, 137, 140, 143, 147, 160, 161, 162, 163, 168, 171, 176, 182, 184, 191, 194 , 195, 198, 203, 204, 207, 209, 211, 214, 220, 221, 222, 231, 235, 236,
C. I. Reactive Green 8, 12, 15, 19, 21,
C. I. Reactive Brown 2,7,9,10,11,17,18,19,21,23,31,37,43,46,
C. I. Reactive Black 5, 8, 13, 14, 31, 34, 39 etc. are mentioned.

  Specific compounds of direct dyes preferable for the present invention are shown below. However, it is not limited to the compound illustrated to these.

C. I. Direct Yellow 8, 9, 10, 11, 12, 22, 27, 28, 39, 44, 50, 58, 86, 87, 98, 105, 106, 130, 137, 142, 147, 153,
C. I. Direct Orange 6, 26, 27, 34, 39, 40, 46, 102, 105, 107, 118,
C. I. Direct Red 2, 4, 9, 23, 24, 31, 54, 62, 69, 79, 80, 81, 83, 84, 89, 95, 212, 224, 225, 226, 227, 239, 242, 243, 254
C. I. Direct Violet 9, 35, 51, 66, 94, 95
C. I. Direct Blue 1, 15, 71, 76, 77, 78, 80, 86, 87, 90, 98, 106, 108, 160, 168, 189, 192, 193, 199, 200, 201, 202, 203, 218, 225 , 229, 237, 244, 248, 251, 270, 273, 274, 290, 291
C. I. Direct Green 26, 28, 59, 80, 85,
C. I. Direct Brown 44, 44: 1, 106, 115, 195, 209, 210, 212: 1, 222, 223,
C. I. Direct Black 17, 19, 22, 32, 51, 62, 108, 112, 113, 117, 118, 132, 146, 154, 159, 169,
Examples of the water-soluble organic solvent of the present invention include polyhydric alcohols (for example, ethylene glycol, glycerin, 2-ethyl-2- (hydroxymethyl) -1,3-propanediol, tetraethylene glycol, triethylene glycol, Tripropylene glycol, 1,2,4-butanetriol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, 1,6-hexanediol, 1,2-hexanediol, 1,5-pentanediol, 1,2- Pentanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 3-methyl-1,3-butanediol, 2 -Methyl-1,3-propanediol, etc.), amines For example, ethanolamine, 2- (dimethylamino) ethanol, etc.), monohydric alcohols (eg, methanol, ethanol, butanol, etc.), polyhydric alcohol alkyl ethers (eg, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol) Monomethyl ether, triethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, etc.), 2,2'-thiodiethanol, amides (eg N N-dimethylformamide), heterocycles (2-pyrrolidone, etc.), acetonitrile, etc. It is below. The amount of the water-soluble organic solvent is preferably 10 to 60% by mass with respect to the total ink mass.

  The fabric in the present invention is not particularly limited, and examples thereof include various fiber materials such as cotton, silk, wool, nylon, polyester, rayon, and acrylic fiber. It may be.

  In the textile printing method of the present invention, it is preferable to remove impurities and dirt adhering to the fabric in order to obtain a uniform dyed product (scouring step).

  In order to prevent bleeding, it is preferable to apply a pretreatment agent by a pad method, a coating method, a spray method or the like (pretreatment step). Thereafter, an image is formed on the fabric containing fibers that can be dyed with a disperse dye by the ink jet recording method using the ink having the above-described configuration (ink application step), and then the ink is applied. The fabric is heat-treated (coloring step), and the heat-treated fabric is washed (washing step) to complete printing on the fabric and obtain a printed product.

  In the case of the ink-jet printing method of the present invention, natural impurities (oil, fat, wax, pectin, natural pigments, etc.) adhering to the fabric fibers, residues of the chemicals used in the fabric production process (sizing agent, etc.) It is desirable to wash them. As cleaning agents used for cleaning, alkalis such as sodium hydroxide and sodium carbonate, surfactants such as anionic surfactants and nonionic surfactants, enzymes and the like are used.

  The pretreatment is not particularly limited as long as a method suitable for the fiber material and ink is appropriately selected from known methods such as pretreatment of water-soluble polymers on the fabric. For example, it is used for a fabric provided with 0.2 to 50% by mass of at least one substance selected from the group consisting of water-soluble metal salts, polycation compounds, water-soluble polymers, surfactants and water repellents. Therefore, it is possible to prevent a high degree of bleeding, and a high-definition image can be printed on a fabric.

  Moreover, according to the preferable aspect at the time of using an acidic dye, it is preferable that a pretreatment agent comprises the pH adjuster which generate | occur | produces an acid by steaming. Preferable examples of the pH adjusting agent include acid ammonium salts such as ammonium sulfate, ammonium tartrate, or sodium diphosphate. By adding these pH adjusters, there is an advantage that hue stabilization and dyeing properties can be improved. These addition amounts may be appropriately determined in consideration of the dye species and the like, but are preferably about 0.2 to 5% by mass, more preferably about 0.5 to 3% by mass.

  The color development step is a step of developing the original hue of ink by adhering to and fixing the dye in the ink that has only adhered to the fabric surface after printing and is not sufficiently adsorbed and fixed to the fabric. As the method, steaming by steam, baking by dry heat, thermosol, HT steamer by superheated steam, HP steamer by pressurized steam, etc. are used. They are appropriately selected depending on the material to be printed, ink and the like. Further, the printed fabric may be immediately heat-treated or may be heat-treated after a while and may be dried and colored according to the intended use, and any method may be used in the present invention.

  A cleaning step is necessary after the heat treatment. This is because a dye that has not participated in the dyeing remains, resulting in poor color stability and low fastness.

  It is also necessary to remove the pretreatment product applied to the fabric.

  If left as it is, not only the fastness is lowered, but also the fabric is discolored.

  Therefore, cleaning according to the object to be removed and the purpose is essential. The method is selected according to the material and ink to be printed. For example, in the case of polyester, treatment is generally performed with a mixed solution of caustic soda, a surfactant, and hydrosulfite. The method is usually carried out in a continuous type such as an open soaper or in a batch type using a liquid dyeing machine, and any method may be used in the present invention.

  Drying is required after washing. After the washed fabric is squeezed or dehydrated, it is dried or dried using a dryer, heat roll, iron or the like.

  In order to maintain the long-term storage stability of the ink, an antiseptic and an antifungal agent may be added to the ink. Examples of the antiseptic / antifungal agent include aromatic halogen compounds (for example, Preventol CMK), methylene dithiocyanate, halogen-containing nitrogen sulfur compounds, and 1,2-benzisothiazolin-3-one (for example, PROXEL GXL). The present invention is not limited to these.

  It is preferable that a dyeing assistant is included in the inkjet ink for printing used for dyeing by the high-temperature steaming method or the fabric used for printing. The dyeing aid has the effect of making eutectic mixture with the water condensed in the form of cloth when steaming the printed fabric, reducing the amount of water that re-evaporates, and shortening the heating time. Further, this eutectic mixture has the effect of dissolving the dye on the fiber and promoting the diffusion rate of the dye into the fiber. Urea is mentioned as a dyeing assistant.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, the embodiment of this invention is not limited to these.

  Inkjet textile printing inks 1 to 23 having the following contents were prepared.

C. I. Acid Yellow 79 9 parts Ethylene glycol 25 parts Glycerin 10 parts Proxel GXL (manufactured by Avicia) 0.1 part Fine particles (activated carbon particles) The number of ion-exchanged water shown in Table 1 The number of fine particles is 0.02 μm to 0. An 8 μm membrane filter was selected to control the number of fine particles in the ink. Measurement of number of fine particles is a Coulter counter (BECKMAN COULTER, Inc., Multisizer 3) performed by using an aperture diameter 50μm at, number of fine particles in the in-click (1 ml) are shown in Table 1.

Continuous emission test 1
Emission state when the manufactured ink is continuously driven for 5 minutes using a Konica Minolta IJ Co., Ltd. share mode type piezo head (256 nozzles) under a driving condition of a driving frequency of 19 kHz and a droplet velocity of 7 m / s. The number of nozzles that did not emit normally due to the occurrence of defects was counted and evaluated as follows.

Continuous emission test 2
Emission state when the manufactured ink is continuously driven for 5 minutes using a Konica Minolta IJ Co., Ltd. share mode type piezo head (256 nozzles) under a driving frequency of 12 kHz and a droplet speed of 7 m / s. The number of nozzles that did not emit normally due to the occurrence of defects was counted and evaluated as follows.

Continuous emission test 3
Emission state when the manufactured ink is continuously driven for 5 minutes using a Konica Minolta IJ Co., Ltd. share mode type piezo head (256 nozzles) under a driving frequency of 8 kHz and a droplet speed of 7 m / s. The number of nozzles that did not emit normally due to the occurrence of defects was counted and evaluated as follows.

Continuous emissivity test after storage After the prepared ink was stored in a thermostat at 60 ° C. for 2 weeks, a Konica Minolta IJ Co., Ltd. share mode type piezo head (256 nozzles) was used, the driving frequency was 19 kHz, and the droplet velocity was 7 m. The emission state when continuously driven for 60 minutes under a driving condition of / s was observed, the number of nozzles that did not normally emit, such as bending, was counted, and the following evaluation was performed.

A: No nozzle missing or oblique emission does not occur. O: No nozzle missing, but no oblique emission. There is no problem with the image quality. Δ: No nozzle missing, but no more than 10 diagonal exits. Level at which there is no problem in image quality x: Nozzle missing occurs within 10 nozzles or oblique emission is 11 or more. Uneven level for practical use due to streaks in the image quality. XX; 10 or more nozzles are missing or a large number of oblique emission occurs. The image quality is unacceptable for practical use due to streaks and density variations.

  It can be seen that the present invention is excellent both in the emission test, particularly in the emission characteristics when the head is driven at high speed and the emission test after storage.

Claims (6)

In an ink for inkjet printing containing at least water, a water-soluble dye purified with activated carbon, and a water-soluble organic solvent,
The content of the water-soluble dye is 5 to 20% by mass,
An ink for ink-jet printing, comprising 5 × 10 ² to 80 × 10 ³ particles / ml of activated carbon fine particles having a particle size of 1 to 30 nm in the ink for ink-jet printing. ^2. The ink for ink-jet printing according to claim 1, wherein the content of the activated carbon fine particles is 5 × 10 ^{2 to} 20 × 10 ³ particles / ml. The ink for inkjet printing according to claim 1 or 2, wherein a degassing step using a hollow fiber membrane is used after ink preparation. The ink for inkjet printing according to claim 3, wherein the deaeration step includes a deaeration step using a hollow fiber membrane and an ultrasonic treatment device. An ink-jet textile printing method, wherein the ink-jet textile ink according to any one of claims 1 to 4 is printed using a print head having a driving frequency of 10 kHz to 20 kHz. The inkjet printing method according to claim 5, wherein the print head ejects ink using a piezo drive system to perform printing.