JP4072487B2 - Aqueous ink, ink jet recording method, ink tank, recording unit, and ink jet recording apparatus - Google Patents

Description

  The present invention relates to an ink, particularly an ink for ink jet recording, and more particularly, an aqueous ink that gives an image with improved discoloration in a room, an ink jet recording method using the same, and an ink tank, a recording unit, and an ink jet used therefor The present invention relates to a recording apparatus.

  The image obtained by inkjet recording has become high definition, and now it is comparable to the image quality of silver halide photography, which is synonymous with high image quality. Next, it is a major concern for users whether it is possible to store the high-definition image together with the initial image without deterioration over a long period of time. From the viewpoint of long-term storage of images, conventionally, fading due to light has been regarded as a problem, and the solution has been achieved by selecting a dye having excellent light resistance. For example, as a dye for cyan ink, C.I. I. Direct Blue 199 and C.I. I. Direct Blue 86 has been used.

  When ink-jet recordings are handled in the same way as “photographs”, there are many opportunities to display them in the indoor environment. In such a case, even though a dye having excellent light resistance is used, the color may be changed in a short period of time. These discoloration colors in the room are caused by environmental gases such as ozone, nitrogen oxides, and sulfur oxides in the atmosphere, and proceed even in places where little light is applied. Especially, coated paper using inorganic pigment as the coating layer. Then, it occurs in a relatively short period.

  C. has been used conventionally. I. Direct Blue 199 and C.I. I. A dye such as Direct Blue 86 in which a sulfone group or a sulfonamide group is introduced into copper phthalocyanine to impart water solubility cannot solve this problem. Therefore, in order to improve the gas resistance, a technique for improving the gas resistance by introducing a substituent different from direct blue 199 or the like into the copper phthalocyanine skeleton, or a dye having a different skeleton is used. Thus, a technique for improving gas resistance has been filed. For example, in Patent Document 1, as a cyan dye compound having excellent gas resistance and used for an ink jet ink, an aminating agent is used with respect to 1 mol of raw material copper phthalocyanine when a copper phthalocyanine is chlorosulfonated and then amidated. A compound obtained by reacting at a ratio of 2.5 mol or more and a mixture of compounds represented by the following formula (II) is disclosed:

(Wherein M represents a proton, an alkali metal ion, an alkaline earth metal ion, an onium ion or an ammonium ion of an organic amine, m is an integer of 1 to 4, n is an integer of 0 to 3, and m + n is an integer from 1 to 4.)
JP 2002-105349 A

  However, when the present inventors examined an ink-jet ink containing such a phthalocyanine dye, an image obtained with such an ink may certainly show excellent gas resistance, but in particular, coated paper or gloss On a special medium such as paper, a new problem has been found that the water resistance is extremely poor and a metallic luster caused by dye aggregation on the recording medium is called bronzing.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a blue water-based ink that gives an image having high saturation, hardly causing discoloration and fading, excellent water resistance, and no bronzing.

  Another object of the present invention is to provide an ink jet recording method using such water-based ink, and an ink tank, a recording unit and an ink jet recording apparatus used therefor.

That is, the present invention provides an aqueous ink containing a phthalocyanine dye represented by the following formula (I) and an aqueous medium, the phthalocyanine dye does not contain a component of x + y = 2, and a component of x + y = 3 and an amine compound containing at least a component of x + y = 4, a content of a component of x + y = 4 being larger than a content of a component of x + y = 3, and the aqueous medium having a vapor pressure of 0.01 mmHg (20 to 25 ° C.) or more It is a water-based ink characterized by containing 2-pyrrolidone as

(In the formula, CuPc represents a copper phthalocyanine residue, x is 1, 2, 3 or 4, and y is 0, 1, 2 or 3.)
The present invention also provides an ink jet recording method using the water-based ink, and an ink tank, a recording unit, and an ink jet recording apparatus used therefor.

  According to the present invention, cyan ink that has high saturation and is less likely to cause discoloration, particularly a water-based ink that is less discolored when recorded on coated paper using an inorganic pigment as a coating layer, and such a water-based ink are used. An ink jet recording method, and an ink tank, a recording unit, and an ink jet recording apparatus used therefor can be obtained.

  According to the present invention, by using a specific dye as a dye for cyan ink and using a specific compound as an aqueous medium, printing with less discoloration in the room, excellent water resistance, and no bronzing phenomenon. Things are obtained.

  The dye represented by the formula (I) in the present invention has a structure very close to a dye called Direct Blue 199 in that sulfonic acid and sulfonamide are bonded to copper phthalocyanine.

The present inventors paid attention to the types and number of substituents in copper phthalocyanine. As a result, not only that the 2-substituted product deteriorates the performance such as the water resistance of the image, but also the existence ratio of SO ₃ ^— groups and SO ₂ NH ₂ groups and the properties of the solvent used are gas resistance, water resistance Furthermore, it has been found that it has a very large influence on the bronze resistance, and has led to the present invention.

  The aqueous ink according to the present invention includes a phthalocyanine dye represented by the following general formula (I).

  In the formula, CuPc represents a copper phthalocyanine residue, x is 1, 2, 3 or 4, and y is 0, 1, 2 or 3.

  In order to contain the above ions in the water-based ink, it is preferable to add a phthalocyanine dye represented by the following formula.

  In the above formula, CuPc represents a copper phthalocyanine residue. M represents an alkali metal (for example, Li, Na, K, Rb, Cs, Fr, etc.) or ammonium. X is 1, 2, 3 or 4, and y is 0, 1, 2 or 3.

  In the present invention, the phthalocyanine dye does not contain a component of x + y = 2, contains at least a component of x + y = 3 and a component of x + y = 4, and x + y = 4 from the content of the component of x + y = 3. A phthalocyanine dye having a higher component content is used. Here, “not contained” in the present invention is not contained at all, but it is contained in a very small amount within the range where the remarkable effects of the present invention can be obtained, that is, substantially contained. Including the case where it is not.

  Further, in the present invention, since the component x + y = 3 is contained more than the component x + y = 4, the gas resistance is particularly good. The ratio is the peak height A of the component of x + y = 4 and the peak height B of the component of x + y = 3 when the compound of formula (I) is analyzed by high performance liquid chromatography at a wavelength of 254 nm corresponding to absorption of the benzene ring. It can be obtained from In the present invention, it is preferable that A / B exceeds 1. Furthermore, if it is 1.5 or more, very excellent gas resistance is exhibited. Further, from the viewpoint of suppressing the bronze phenomenon, A / B is preferably 9 or less, particularly 4 or less.

  In the present invention, y is preferably 1 or more from the viewpoint of suppressing the bronze phenomenon.

  The dye concentration in the aqueous ink of the present invention is preferably 0.1 to 10% by mass with respect to the mass of the whole ink. More preferably, it is 0.1-6 mass%. In order to reduce the graininess of highlights, photographic image quality printer ink is sometimes used in combination with low-dye ink, called photo ink (light ink), and normal ink. As the ink, 0.1 to 2% by mass, and as the normal concentration ink, 2 to 6% by mass is preferably used.

The phthalocyanine dye used in the present invention is
1. Copper phthalocyanine is sulfonated with chlorosulfonic acid, followed by sulfonamidation of the sulfonic acid with ammonia.
2. Sulfonated, sulfonamidated phthalic acid and phthalonitrile are used as starting materials to form copper phthalocyanine, followed by sulfonamidation if necessary.
It can synthesize | combine by normal methods, such as.

-Physical properties of ink The physical properties of the ink are preferably controlled from the viewpoint of ink jet suitability. The surface tension of the ink is preferably 20 to 50 mN / m. The viscosity of the ink is preferably 1 to 5 mPa · s, more preferably 1 to 2.5 mPa · s. The pH of the ink is preferably in the range of 6 to 10.5.

-Aqueous medium The aqueous medium basically contains water as a main component and may contain a water-soluble organic solvent. And in this invention, the water resistance which is the subject of the image excellent in the gas resistance formed with the ink containing the above-mentioned phthalocyanine dye is a vapor pressure of 0.01 mmHg (20-25 degreeC) or more in an aqueous medium. By containing an amine compound, it can be greatly improved. The reason why the water resistance of the image is improved by containing such an amine compound is not clear, but is presumed as follows.

  The amine compound controls the state of association in the ink, particularly for the dyes as shown in the present invention, for the bronze phenomenon due to the aggregation of the dye after printing and the insufficient fixing to the recording medium due to the state of association of the dye. It effectively suppresses the deterioration of water resistance based on it.

  However, when the vapor pressure of the solvent is low to a vapor pressure of less than 0.01 mmHg (20 to 25 ° C.), particularly about 0.001 mmHg (20 to 25 ° C.) or less, which is an order of magnitude smaller, the solvent in the ink applied by printing is printed. It may be said that it hardly evaporates in the material.

  Therefore, when the print media absorbs moisture due to humidification or the like, the solvent may interact with the dye, and the remaining amine solvent may deteriorate the gas resistance. On the other hand, a solvent having a vapor pressure of 0.01 mmHg (20 to 25 ° C.) or more decreases with time and does not adversely affect gas resistance. Thereby, it is considered that the gas resistance when the printed matter is left in an environment exposed to air is maintained, and the bronze resistance and water resistance are improved. This is particularly effective when the viscosity of the ink is to be controlled to 1 to 5 mPa · s, more preferably 1 to 2.5 mPa · s.

  On the other hand, the vapor pressure of the amine compound used in the present invention is preferably 12 mmHg (20 to 25 ° C.) or less. If this range is exceeded, the volatility becomes too high and it becomes difficult to obtain the effect of the solvent.

  Preferable specific examples of the amine compound having a vapor pressure of 0.01 mmHg (20 to 25 ° C.) or more include, for example, 2-pyrrolidone, morpholine, mono, di, and triethanolamine. From the viewpoint of the effect of improving the water resistance of an image. The content of the amine compound in the ink is preferably 2 to 20% by mass, particularly 4 to 10% by mass based on the total mass of the ink.

  Further, without impairing the effect of improving the water resistance of the image due to the addition of an amine compound having a vapor pressure of 0.01 mmHg (20 to 25 ° C.) or more to the aqueous medium, the inkjet discharge characteristics of the ink, specifically, In order to make the ink discharge property, that is, the intermittent discharge property, excellent when the ink is discharged from a certain nozzle and then the ink discharge is temporarily interrupted and then the ink is discharged again from the nozzle, the vapor pressure is zero. It is preferable to contain glycols of 0.01 mmHg (20 to 25 ° C.) or more in an aqueous medium. Examples of such glycols include ethylene glycol. The content of such glycols in the ink is preferably 2 to 20% by mass, particularly 3 to 10% by mass.

  Furthermore, in the present invention, the mass ratio (2-pyrrolidone: ethylene glycol) of 2-pyrrolidone and ethylene glycol is 1: 2 to 2: 1 in terms of ejection characteristics, water resistance and bronze resistance. Particularly preferred.

Table 1 shows vapor pressures of typical water-soluble organic solvents at 20 to 25 ° C. For each data, the solvent handbook first edition (Kodansha) and the solvent pocket book (Ohm) were referred. For compounds with no vapor pressure description at 20 to 25 ° C., the temperature-vapor pressure data described in the third edition of the Basic Manual of Chemical Handbook (Maruzen) is obtained from the relationship of the following equation derived from the Clapeyron-Clauius equation: From, it calculated | required in conversion into the vapor pressure of 20 degreeC and 25 degreeC.
lnP = −ΔHvap / RT + C
(P is vapor pressure, ΔHvap is heat of molar evaporation (constant), R is gas constant, T is temperature, and C is constant)

  In the present invention, the term “vapor pressure of 0.01 mmHg (20 to 25 ° C. or higher)” means that a temperature at which the vapor pressure becomes 0.01 mmHg or higher between 20 ° C. and 25 ° C. may be present. The vapor pressure need not be 0.01 mmHg or more over the entire temperature range. Conversely, “vapor pressure of 12 mmHg (20 to 25 ° C. or lower)” means that the vapor pressure is 12 mmHg or lower in the entire temperature range of 20 ° C. to 25 ° C.

-Surfactant In addition to the above-mentioned substances, known substances as surfactants for adjusting the surface tension can be widely used as the aqueous medium. For example, anionic surfactants such as fatty acid salts, higher alcoholic acid ester salts, alkylbenzene sulfonates and higher alcohol phosphoric acid ester salts; cationic surfactants such as aliphatic amine salts and quaternary ammonium salts; higher alcohol ethylene oxide Adduct, alkylphenol ethylene oxide adduct, aliphatic ethylene oxide adduct, polyhydric alcohol aliphatic ester ethylene oxide adduct, aliphatic amide ethylene oxide adduct, higher alkylamine ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, Nonionic surfactants such as fatty acid esters of polyhydric alcohols and fatty acid amides of alkanolamines; amphoteric surfactants such as amino acid type and betaine type are used. Although there is no particular limitation, a nonionic surfactant such as an ethylene oxide adduct of a higher alcohol, an ethylene oxide adduct of an alkylphenol, an ethylene oxide-propylene oxide copolymer, an ethylene oxide adduct of acetylene glycol or the like is more preferable. Use. Furthermore, the number of moles added of the ethylene oxide adduct is preferably in the range of 4-20.

  In particular, it is desirable to use a nonionic surfactant such as an adduct of ethylene oxide of acetylene glycol from the viewpoint of matching with a print head and printing characteristics on plain paper.

Recording method and apparatus As a recording apparatus suitable for recording using the ink of the present invention, the heat corresponding to the recording signal is applied to the ink in the chamber of the recording head having the ink storage portion for storing these inks. Examples thereof include an apparatus that applies energy and generates ink droplets by the energy.

  FIG. 1 shows an example of an ink jet recording apparatus incorporating this head. In FIG. 1, reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member to become a fixed end and form a cantilever. The blade 61 is disposed at a position adjacent to the recording area by the recording head, and in the case of the example shown in FIG. 1, is held in a form protruding in the moving path of the recording head. Reference numeral 62 denotes a cap, which is disposed at a home position adjacent to the blade 61 and moves in a direction perpendicular to the moving direction of the recording head so as to come into contact with the ejection surface and perform capping. Further, reference numeral 63 in FIG. 1 denotes an ink absorber provided adjacent to the blade 61 and, like the blade 61, is held in a form protruding in the moving path of the recording head.

  The blade 61, the cap 62, and the absorber 63 constitute a discharge recovery portion 64, and the blade 61 and the absorber 63 remove moisture, dust, dust, and the like from the ink discharge port surface. Reference numeral 65 denotes a recording head that has discharge energy generating means and performs recording by discharging ink onto a recording material facing the discharge port surface on which the discharge ports are arranged. It is a carriage for performing the movement. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68. Accordingly, the carriage 66 can move along the guide shaft 67, and the recording area by the recording head 65 and its adjacent area can be moved.

  Reference numeral 51 denotes a paper feed unit for inserting a recording material, and 52 denotes a paper feed roller driven by a motor (not shown). With these configurations, a recording material is fed to a position facing the ejection port surface of the recording head, and is discharged to a paper discharge unit provided with a paper discharge roller 53 as recording progresses.

  In the above configuration, when the recording head 65 returns to the home position due to the end of recording or the like, the cap 62 of the head recovery unit 64 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. As a result, the ejection port surface of the recording head 65 is wiped. When the cap 62 is in contact with the ejection surface of the recording head 65 to perform capping, the cap 62 moves so as to protrude into the moving path of the recording head.

  When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same position as that at the time of wiping described above. As a result, even in this movement, the ejection port surface of the recording head 65 is wiped. The above-mentioned movement of the recording head to the home position is performed not only at the end of recording or at the time of recovery of ejection, but also to the home position adjacent to the recording area at a predetermined interval while the recording head moves the recording area for recording. In accordance with this movement, the wiping is performed.

  FIG. 2 is a cross-sectional view showing an example of an ink cartridge 45 that contains ink supplied to the head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink container, for example, an ink bag, in which supply ink is stored, and a rubber plug 42 is provided at the tip thereof. By inserting a needle (not shown) into the stopper 42, the ink in the ink bag 40 can be supplied to the head. An ink absorber 44 receives waste ink.

  The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge as described above are separated, and an apparatus in which they are integrated as shown in FIG. 3 is also preferably used. In FIG. 3, reference numeral 70 denotes a recording unit, in which an ink storage portion that stores ink, for example, an ink absorber is stored, and the ink in the ink absorber has a plurality of orifices. 71 is ejected as ink droplets. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. The recording unit 70 is used in place of the recording head 65 shown in FIG. 1, and is detachable from the carriage 66.

  FIG. 4 shows an example of an ink jet cartridge that can be mounted on the above-described ink jet recording apparatus. The cartridge 1012 in this example is of a serial type, and the main part is composed of the ink jet recording head 100 and a liquid tank 1001 for containing a liquid such as ink. The inkjet recording head 100 is formed with a number of ejection ports 832 for ejecting liquid, and liquid such as ink is supplied from the liquid tank 1001 to a common liquid chamber of the liquid ejection head 100 via a liquid supply passage (not shown). It has come to be guided. A cartridge 1012 shown in FIG. 4 is formed by integrally forming an ink jet recording head 100 and a liquid tank 1001 so that liquid can be supplied into the liquid tank 1001 as necessary. A structure in which a liquid tank 1001 is connected to 100 in a replaceable manner may be adopted.

Recording medium As the recording medium that can be used in the present invention, any recording medium can be used as long as it is a recording medium on which ink is attached.

  The present invention is applied to a recording medium in which a coloring material such as a dye or a pigment is adsorbed to fine particles forming a porous structure in an ink receiving layer and an image is formed from at least the adsorbed fine particles. It is particularly suitable for use. Such an ink jet recording medium is preferably a so-called absorption type in which ink is absorbed by a gap formed in an ink receiving layer on a support. The absorption type ink-receiving layer is constituted as a porous layer mainly composed of fine particles and containing a binder and other additives as required. Examples of fine particles include inorganic pigments such as silica, clay, talc, calcium carbonate, kaolin, alumina or alumina hydrate, diatomaceous earth, titanium oxide, hydrotalcite, zinc oxide, urea formalin resin, ethylene resin And organic pigments such as styrene resins, and one or more of these are used. Examples of suitable binders include water-soluble polymers and latex. For example, polyvinyl alcohol or a modified product thereof, starch or a modified product thereof, gelatin or a modified product thereof, gum arabic, carboxymethylcellulose, hydroxyethylcellulose, hydroxyprooylmethylcellulose and other cellulose derivatives, SBR latex, NBR latex, methylmethacrylate-butadiene Polymer latex, functional group-modified polymer latex, vinyl copolymer latex such as ethylene vinyl acetate copolymer, polyvinyl pyrrolidone, maleic anhydride or copolymer thereof, acrylic ester copolymer, etc. are used and necessary Depending on, two or more types can be used in combination. In addition, additives can also be used. For example, a dispersant, a thickener, a pH adjuster, a lubricant, a fluidity modifier, a surfactant, an antifoaming agent, a mold release agent, a fluorescence enhancer, if necessary. Whitening agents, ultraviolet absorbers, antioxidants and the like are used.

  In particular, the recording medium that can be suitably used in the present invention is preferably a recording medium in which an ink receiving layer is mainly formed of fine particles having an average particle diameter of 1 μm or less as the fine particles. Particularly preferable examples of the fine particles include silica or aluminum oxide fine particles. A preferable silica fine particle is a silica fine particle typified by colloidal silica. Colloidal silica itself is also available from the market, and particularly preferable examples include those described in Japanese Patent Nos. 2803134 and 2881847. Preferable examples of the aluminum oxide fine particles include alumina hydrate fine particles. As one of such alumina-based pigments, preferred is an alumina hydrate represented by the following general formula (III).

In said formula (III), n represents either the integer of 1, 2, or 3, m represents 0-10, Preferably the value of 0-5 is represented. However, m and n are not 0 at the same time. Since mH ₂ O also represents a detachable aqueous phase that often does not participate in the formation of the mH ₂ O crystal lattice, m can take an integer or non-integer value. Also, when this type of material is heated, m can reach a value of zero. Alumina hydrate is generally used for hydrolysis of aluminum alkoxide and sodium aluminate as described in U.S. Pat. No. 4,242,271 and U.S. Pat. No. 4,420,870. It is preferable to use a solution prepared by a known method such as a method in which an aqueous solution of sodium sulfate, aluminum chloride or the like is added to an aqueous solution of sodium aluminate or the like described in US Pat.

Next, the present invention will be described more specifically with reference to Examples , Reference Examples and Comparative Examples.

(Examples 1-3, Reference Example 4 and Comparative Examples 1-2)
By the above-mentioned method, phthalocyanine dyes 1 to 3 used in this example were prepared.

  The obtained dye was analyzed by high performance liquid chromatography (trade name: LC / MS; manufactured by Waters). Waters Symmetry C18 was used as a column, and water / ammonium acetate / acetonitrile solvent as a mobile phase was analyzed under gradient conditions. The chromatogram of each dye 1-3 is shown in FIGS.

Analysis of each component, from the chart of MS, those MH ⁺ ions of 734~735 x + y = 2, MH + ions those 814~816 x + y = 3, MH + ions things 894-896 x + y = 4 and counted.

The attribution results are shown in Table 2. Table 3 shows dyes 1 to 3 used in Examples , Reference Examples and Comparative Examples. In the table, x + y represents x + y in the dye of the general formula (I), and each number is the sum of each peak height in the liquid chromatogram.

  Each component shown in Table 4 was mixed, dissolved sufficiently by stirring, and then filtered under pressure with a microfilter having a pore size of 0.2 μm (manufactured by Fuji Film) to prepare a cyan ink.

  Evaluation of printed matter using an inkjet recording apparatus BJF-870 (manufactured by Canon Inc.) having an on-demand type multi-recording head that discharges ink by applying thermal energy corresponding to a recording signal to the ink using the ink described above. Went.

  As a paper for evaluating gas resistance, Professional Photo Paper PR-101 (manufactured by Canon) using an inorganic pigment as a coating layer was used.

  The evaluation items are as follows.

1. Gas fastness Solid prints with a 50% duty were exposed for 2 hours at an ozone concentration of 3 ppm at a temperature of 45 ° C. and a relative humidity of 55%.
The optical density (OD) was evaluated as follows as a residual ratio with respect to the initial stage. OD was measured by Spectrolino (manufactured by Gretag).
A: Residual rate 80% or more B: Residual rate 70 or more and less than 80% C: Residual rate 70% or less Water resistance A cyan color bar having a width of 3 mm and an interval of 3 mm was printed, and the printed matter was inclined 45 degrees, and 1.5 ml of tap water was poured from the upper surface. After drying, color oozing was observed visually.
A: No color bleeding B: Slight color bleeding C: Many color bleeding Bronze Phenomenon A 3 cm square 100% solid cyan color patch was printed, and the printed matter was visually observed from the top surface at an angle of 45 degrees under a fluorescent lamp.
A: In all cases, it is observed in exactly the same way.
C: Something like metallic luster is observed, or the color changes depending on the viewing angle.
4). Ink discharge characteristics Printing of fine ruled lines and pausing were repeated in an environment of 15 ° C. and 10% relative humidity, and the printing state was observed.
AA: Printing has not been disturbed for a long time, and fine ruled lines can be recognized. A: When left for a long time, some writing parts are disturbed. B: For some long time leaving, some writing parts. Table 4 shows the evaluation results. From this result, it can be seen that the ink according to the present invention provides an ink jet image in which both the gas resistance and the water resistance are compatible at a high level and the bronzing phenomenon is also suppressed.

(Examples 5 to 8)
A cyan ink was prepared and evaluated in the same manner as in Example 1 except that the ink composition shown in Table 5 was used. The results are shown in Table 5.

  From the results shown in Tables 4 and 5 above, the phthalocyanine according to the present invention which does not contain a substitution product of x + y ≦ 2, 2-pyrrolidone as an amine compound having a vapor pressure of 0.01 mmHg (20 to 25 ° C.), and steam An ink containing ethylene glycol as a glycol having a pressure of 0.01 mmHg or more (20 to 25 ° C.) gives particularly excellent ink jet images in terms of water resistance and bronze resistance, and also has ink jet characteristics (discharge characteristics). It turns out that it is excellent.

(Comparative Examples 3-4)
A cyan ink was prepared and evaluated in the same manner as in Example 1 except that phthalocyanine dyes 4 and 5 as shown in Table 6 were used and the composition shown in Table 7 was used. The results are shown in Table 7. In Table 6, x + y represents x + y in the dye of the general formula (I), and each number is the sum of each peak height in the liquid chromatogram.

It is a perspective view which shows an example of an inkjet recording device. It is a longitudinal cross-sectional view of an ink cartridge. It is a perspective view of a recording unit. It is a schematic perspective view showing an example of an ink jet cartridge provided with a liquid discharge head. 2 is a liquid chromatogram of Dye 1. 3 is a liquid chromatogram of Dye 2. 3 is a liquid chromatogram of Dye 3.

Claims (14)

In an aqueous ink containing a phthalocyanine dye represented by the following formula (I) and an aqueous medium,
The phthalocyanine dye does not contain a component of x + y = 2, contains at least a component of x + y = 3 and a component of x + y = 4, and the content of the component of x + y = 4 is larger than the content of the component of x + y = 3,
The aqueous medium contains 2-pyrrolidone as an amine compound having a vapor pressure of 0.01 mmHg (20 to 25 ° C.) or higher.

(In the formula, CuPc represents a copper phthalocyanine residue, x is 1, 2, 3 or 4, and y is 0, 1, 2 or 3.)   The water-based ink according to claim 1, wherein the vapor pressure of the amine compound is 12 mmHg (20 to 25 ° C.) or less.   3. High-performance liquid chromatography analysis at a measurement wavelength of 254 nm, wherein the peak height A of the component of x + y = 4 and the peak height B of the component of x + y = 3 satisfy A / B> 1. Water-based ink.   The aqueous ink according to claim 3, wherein A / B is 1.5 or more.   The water-based ink according to claim 3 or 4, wherein A / B is 9 or less. The aqueous ink according to any one of claims 1 to 5, a vapor pressure further includes a 0.01 mmHg (20-25 ° C.) or more glycols. The water-based ink according to claim 6 , wherein the glycol is ethylene glycol. The water-based ink according to claim 7, comprising the 2-pyrrolidone and the ethylene glycol in a mass ratio of 1: 2 to 2: 1.   The water-based ink according to any one of claims 1 to 8, which is for inkjet recording. In an inkjet recording method having a step of discharging a water-based ink onto a recording medium by an inkjet method,
An ink jet recording method, wherein the water-based ink is the water-based ink according to any one of claims 1 to 9. The ink jet recording method according to claim 10, wherein the ink jet recording method discharges ink by applying thermal energy to the ink. In an ink tank having an ink storage section for storing aqueous ink,
An ink tank, wherein the water-based ink is the water-based ink according to any one of claims 1 to 9. In a recording unit having a water-based ink and an inkjet recording head for discharging the water-based ink,
A recording unit, wherein the water-based ink is the water-based ink according to claim 1. In an inkjet recording apparatus having an aqueous ink and an inkjet recording head for discharging the aqueous ink,
An ink jet recording apparatus, wherein the water-based ink is the water-based ink according to any one of claims 1 to 9.

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