JP2003012968A - Ink composition and recording apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ink composition which contains a crystalline colored organic pigment, does not cause blur or offset in recording on plain paper, is excellent in resistances to water, light, and rubbing, and enables high- color-density high-quality (high-definition high-chroma) recording; and a recording apparatus using the ink composition and capable of both-sides simultaneous printing. SOLUTION: This aqueous ink composition contains, as the main ingredients, a crystalline colored organic pigment of which the half value width of a diffraction ray with the maximum strength in the X-ray diffraction spectrum is 0.4 deg. or lower and an organic compound having a hydrophilic site and a hydrophobic site in the molecule.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition containing a crystalline color organic pigment suitable for recording (printing) in an ink jet recording system and a recording apparatus using the same. The ink composition of the present invention can be suitably used as a coloring agent for various marking tools and instruments.

[0002]

2. Description of the Related Art An ink jet recording system is a system for ejecting small droplets of ink by various mechanisms, adhering the small droplets on a medium, forming dots to record an image. Therefore, there are features such as low noise during recording, easy full colorization, no need for development and fixing, and high speed recording. In recent years, the inkjet recording method has been drawing attention as a method for printing color images, various figures, color originals, and the like displayed on a display or the like, and has rapidly spread.

The ink used for recording in the ink jet recording system is required to have contradictory characteristics such that it quickly dries and fixes on a medium, is hard to dry in a nozzle, and is unlikely to cause nozzle clogging. In addition, storage stability and safety are also required as basic performance. Further, since the permeation / absorption state of ink varies greatly depending on the type of media, there is a problem that the usable paper is limited.
In particular, in recent years, it has been required that good recording can be performed even on so-called plain paper such as copy paper, report paper, notebooks, and notepapers that are commonly used in offices, and immediate improvement of the above problems is desired. It is rare.

The ink is a composition whose main component is a dye or pigment as a colorant and a solvent for dissolving or dispersing the dye or pigment, and various additives are contained if necessary. Inks using pigments are superior in water resistance and light resistance to inks using water-soluble dyes that are widely used in the office and personal fields, and can be put to practical use in the field of large-format printing for the design and display markets. It is progressing. However, it is difficult to apply to various fields such as office and personal fields where high quality output is required.

As an aqueous ink using a pigment as a colorant, for example, one using porous carbon black having a relatively high polarity (see JP-A-8-3498 and JP-A-10-510862). , Using a microencapsulated organic pigment (see JP-A-9-151342 and JP-A-10-140065), but it is still insufficient in terms of saturation, drying speed, scratch resistance and the like. Absent.

[0006] In the pigment-based ink, it is particularly required that the pigment be stably dispersed in the solvent for a long period of time (storage stability) and that the nozzles of the recording apparatus are not clogged. For example,
JP-A-6-212106 discloses a technique of dispersing a pigment in a solvent using a polymer dispersant, a dispersant such as a surfactant, or the like. However, the addition of such a dispersant generally causes bubbling of the ink and affects the ejection process of the ink, resulting in the problem of uneven printing.

Japanese Patent No. 3000672 discloses an ink jet recording ink in which the occurrence of bleeding is suppressed by controlling the particle diameter of a coloring component (colorant) as a dispersoid and the surface tension characteristic of a dispersion medium within a specific range. Is disclosed. However, in this publication, the diffraction line showing the maximum intensity in the X-ray diffraction spectrum has a specific full width at half maximum (FW).
There is no technical idea of using a crystalline color organic pigment having an HM) and having a specific particle size based on the absorption wavelength of the basic primary color and the maximum and minimum wavelengths in the visible light region as a colorant. Further, there is no disclosure of a technique that suppresses show-through in plain paper recording and enables double-sided printing.

Water resistance and light resistance can be easily achieved by using a pigment having excellent light resistance as a colorant, but as an ink of the ink jet recording system, stable ink ejection is ensured, storage stability of the ink, Fixability on the surface of media becomes a problem. Further, high color density and scratch resistance have not been achieved yet. Furthermore, using a pigment as a colorant, three primary colors, a cyan pigment, a magenta pigment, and a yellow pigment are used.
On the basis of color, turbidity due to color mixing is likely to occur, and high-color recording cannot be realized at present.

[0009]

DISCLOSURE OF THE INVENTION The present invention has a high quality (high definition, high saturation) with high bleeding, no show-through, excellent water resistance, light resistance and scratch resistance with respect to plain paper recording, and high color density. An object of the present invention is to provide an aqueous ink composition containing a recordable crystalline color organic pigment and a recording apparatus capable of simultaneous double-sided printing using the same.

[0010]

As a result of intensive studies to solve the above problems, the inventors of the present invention have found that the full width at half maximum (FW) of the diffraction line showing the maximum intensity in the X-ray diffraction spectrum is FW.
HM), and with such a crystalline color organic pigment,
It was found that the above problems can be solved by configuring the ink composition from a specific organic compound having a hydrophilic site and a hydrophobic site bound in the crystalline color organic pigment with a strong binding action in the molecule, The present invention has been completed. The ink composition of the present invention makes it possible to secure stable ink ejection performance even after being left for a long period of time, and does not cause nozzle clogging at the time of restart.

The present inventors have also found that a more excellent effect can be obtained by using a crystalline color organic pigment that has been hydrophilized using a modification technique. Furthermore, the inventors of the present invention use three colors of a cyan pigment, a magenta pigment, and a yellow pigment as colorants of the ink composition, so that there is no turbidity in the color, and recording is possible with simultaneous printing on both sides. We also found that the device can be realized.

Thus, according to the present invention, a crystalline color organic pigment having a diffraction line showing the maximum intensity in an X-ray diffraction spectrum having a half-value width of 0.4 ° or less, a hydrophilic portion and a hydrophobic portion in the molecule. An ink composition is provided, which comprises an organic compound having a main component as a main component.

According to the present invention, the above-mentioned ink composition containing a crystalline yellow pigment, a crystalline magenta pigment and a crystalline cyan pigment separately as the crystalline color organic pigment is used in combination. A recording device is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Although an aqueous ink composition using a crystalline color organic pigment will be described below, the present invention is not limited to this, and the present invention can be applied to a non-aqueous ink composition.

The ink composition of the present invention comprises a crystalline color organic pigment having a diffraction line showing the maximum intensity in an X-ray diffraction spectrum having a half value width of 0.4 ° or less, a hydrophilic site and a hydrophobic site in the molecule. It is an ink composition characterized in that it contains an organic compound having

The crystalline color organic pigments used in the present invention are crystalline color organic pigments of the three primary colors of yellow, magenta and cyan which satisfy the above conditions, and blue, green and red crystalline colors which are complementary colors. It is an organic pigment.

In such a crystalline color organic pigment, the diffraction line showing the maximum intensity in the X-ray diffraction spectrum is 0.4.
It has a full width at half maximum of not more than °, but the X-ray diffraction spectrum differs depending on the type of pigment.

Preferred examples of the X-ray diffraction spectrum of the crystalline color organic pigment used in the present invention are shown below. In addition, this spectrum shows CuKα ray (0.1540
It is a numerical value when 50 nm) is used. With the crystalline yellow pigment, the black angle (2θ ± 0.2 °) is 11.9 °,
Those having major diffraction peaks at 25.6 ° and 26.8 °, and the diffraction peak at 11.9 ° or 26.8 ° showing the maximum intensity, and a black angle (2θ ± 0.2 °)
Those having major diffraction peaks at 11.1 ° and 27.0 ° and showing the maximum intensity at the diffraction peak at 27.0 ° are mentioned.

The crystalline magenta pigment has major diffraction peaks at black angles (2θ ± 0.2 °) of 5.6 ° and 11.2 °, and the diffraction peak of 5.6 ° has the maximum intensity. The ones shown are listed.

In the crystalline cyan pigment, the black angle (2θ
± 0.2 °) 7.0 °, 9.2 °, 18.2 °, 18.
The major diffraction peak at 6 ° and the diffraction peak at 9.2 ° showing the maximum intensity, and the black angle (2
(.theta .. +-. 0.2.degree.) Those having major diffraction peaks at 7.0.degree., 9.1.degree. and 18.2.degree., and the diffraction peak at 7.0.degree.

The crystalline color organic pigment constituting the colorant of the present invention has a specific range derived from the maximum wavelength and the minimum wavelength of the desired absorption wavelength region in the spectral reflection spectrum, that is, from 1/4 to the minimum of the maximum wavelength. It preferably has a volume average particle diameter in the range of 1/10 of the wavelength. here,
"Volume average particle size" is the value obtained by converting the number average value of volume into particle size, assuming that the particles are cubic, and is obtained based on the data measured with an electrophoretic light scattering meter. You can

The range of the optimum value of the volume average particle diameter of the crystalline color organic pigment differs depending on the type of pigment. The desired (ideal) spectral reflection spectrum and absorption wavelength range (visible light range) of each pigment are 400 nm and 50 nm as shown in FIG.
It is set based on 0 nm, 600 nm and 700 nm. 1A, 1B, and 1C show ideal visible light absorption characteristics of a yellow pigment (blue pigment), a magenta pigment (green pigment), and a cyan pigment (red pigment), respectively. That is, the optimum value of the volume average particle diameter of each pigment is in the range of 1/4 of the maximum wavelength of each absorption wavelength region of the spectral absorption spectrum to 1/10 of the minimum wavelength,
The range is as shown in Table 1.

[0023]

[Table 1]

The particles of the crystalline color organic pigment of the present invention are
Particles of a pigment contained in a conventional ink composition (for example, 10
The particle size of the pigment is much finer than that of (0 to 5000 nm), and by limiting the particle size of the pigment in this manner, the more excellent effects of the present invention (for example, bleeding characteristics and storage stability) are exhibited.

The crystalline color organic pigment becomes transparent as the volume average particle diameter becomes 1/2 or less, especially 1/4 or less of the maximum wavelength of the absorption wavelength range of the pigment. This is a particularly important characteristic for realizing high-quality (high-definition, high-saturation) recording when color overlapping is performed. Further, when the volume average particle diameter of the crystalline color organic pigment is less than 1/10, it enters the Rayleigh scattering region where there is almost no light scattering, and is 200 in terms of stability in the dispersion due to Brownian motion of the particles.
The volume average particle diameter of the crystalline color organic pigment is preferably in this range because the area of nm or less is desired. By using such a crystalline color organic pigment, it is possible to obtain a stable ink composition capable of obtaining a color with high saturation. Also,
The crystalline color organic pigment particles of the present invention have 90% of all particles.
% Or more is preferably included in the range of the volume average particle diameter defined in the present invention, and the distribution thereof has a single peak.

In reality, there is no crystalline color organic pigment exhibiting an ideal spectral reflection spectrum. Therefore, each color is based on the maximum wavelength λ ₁ and the minimum wavelength λ ₂ of the measured values in the absorption wavelength range of the spectral reflection spectrum. You may specify the optimal range of the volume average particle diameter of an organic pigment. That is, the volume average particle diameter of each color organic pigment may be specified as a range of 1/4 of the maximum wavelength of the desired absorption wavelength range to 1/10 of the minimum wavelength in the spectral reflection spectrum. In addition, the maximum / minimum wavelengths referred to here are absorption maximums in the visible light region (400 to
700 nm), the absorption spectrum of 1
It is defined by the intersection of the tangent line and the wavelength axis at the position where the absolute value of the second derivative is maximum (see FIG. 5).

The crystalline color organic pigment used in the present invention preferably has a high affinity with water, and more preferably is one which is modified by a chemical treatment and / or a physical treatment to be hydrophilized. In particular, this treatment is preferably a treatment in which at least one hydrophilic group is chemically adsorbed and / or bound to the surface of the color organic pigment. The chemical treatment and / or physical treatment for modifying the crystalline color organic pigment includes ultraviolet irradiation in an oxygen atmosphere (for example, a low pressure mercury lamp (λ: 185 in an oxygen gas atmosphere.
nm)), exposure in a reactive plasma gas (eg exposure to glow discharge plasma of low pressure oxygen gas under vacuum) and acid treatment (eg in air).
A method of directly treating with fuming sulfuric acid or chlorosulfonic acid).

In the above-mentioned modification treatment for hydrophilization, the resistance of the crystalline color organic pigment is required. In other words, depending on the crystalline color organic pigment, it may decompose or change color during the modification treatment, so it is important to optimize the treatment conditions and select a pigment that is durable.

The crystalline color organic pigment used in the present invention is an azo pigment (eg, monoazo yellow pigment, naphthol AS pigment, benzimidazolone pigment, disazo yellow pigment, etc.) used as a colorant for printing inks, toners and paints. Pyrazolone pigments, condensed azo pigments, etc.), polycyclic pigments (eg, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, thioindigo pigments, ansanthron pigments, etc.) and the like.

Specific examples of the pigment used in the present invention are shown below. Examples of the yellow pigment include monoazo yellow pigments such as CI Pigment Yellow 74, CI Pigment Yellow 13, disazo yellow pigments such as CI Pigment Yellow 83 and CI Pigment Yellow 176, condensed azo pigments such as CI Pigment Yellow 128, and CI Pigment Yellow 151, CI Pigment Yellow 180 and CI Pigment Yellow 1
And benzimidazolone pigments such as 94.

Examples of magenta pigments include quinacridone pigments such as CI Pigment Red 122 and CI Pigment Red 202, CI Pigment Red 149, C.I.
I. Perylene pigments such as CI Pigment Red 190 and CI Pigment Red 224, and CI Pigment Red 175, CI Pigment Red 176 and CI
Pigment Red 185, naphthol AS-benzimidazolone pigment, and the like.

Examples of cyan pigments include phthalocyanine pigments such as CI Pigment Blue 15, CI Pigment Blue 15: 3 and CI Pigment Blue 15: 4.

Examples of blue pigments include phthalocyanine pigments such as CI Pigment Blue 60 and CI Pigment Blue 15: 6. Examples of green pigments include phthalocyanine pigments such as CI pigment green 7 and CI pigment green 36. Examples of red pigments include naphthol AS pigments such as CI Pigment Red 238 and condensed azo pigments such as CI Pigment Red 221.

In the ink composition of the present invention, one type of the above crystalline color organic pigments may be used alone, or two or more types may be used in appropriate combination. Its content is 0.1-10
Weight% is preferable, and 3-8 weight% is more preferable. When the content of the crystalline color organic pigment is less than 0.1% by weight, the printing density becomes low, which is not preferable. Further, when the crystalline color organic pigment exceeds 10% by weight, the viscosity is high,
It is not preferable because the dispersion stability is poor.

The organic compound having a hydrophilic part and a hydrophobic part in the molecule used in the present invention may be a low molecular compound or a high molecular compound as long as it is a compound having a specific molecular structure and a specific structural unit. Such organic compounds are
By combining with a crystalline color organic pigment having a specific volume average particle diameter of the present invention, for plain paper recording,
It is possible to obtain an ink composition which is excellent in water resistance, light resistance, and scratch resistance without bleeding or show-through, and which enables high quality recording with high color density and high saturation. The organic compound having a hydrophilic site and a hydrophobic site in the molecule of the present invention not only secures the dispersion stability of the crystalline color organic pigment of the present invention in an aqueous system, but also can be used after being fixed on a medium. By suppressing the aggregation of the crystalline color organic pigment particles, extremely vivid colors are expressed and the color turbidity is prevented.

Next, the organic compound used in the present invention having a hydrophilic site and a hydrophobic site in the molecule will be described.

Examples of the low molecular weight organic compound include sorbitan monolaurate, sorbitan monostearate, sorbitan monopalmylate, sorbitan monooleate and other sorbitan ester type nonionic surfactants (sorbitan esters), polyoxyethylene. Sorbitan ester ether type nonionic surfactants (sorbitan ester ethers) such as sorbitan monolaurate, polyoxyethylene sorbitan monopalmylate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, and acetylene groups Acetylene glycol-type nonionic surfactant having symmetric structure and having a symmetrical structure (acetylene glycols, for example, marketed by Air Products Japan Co., Ltd.) Which can be mentioned.

Anionic surfactants or cationic surfactants other than nonionic surfactants tend to cause foaming when combined with the crystalline color organic pigment of the present invention, resulting in dispersion stability. It is not preferable because the show-through is large when recorded on a medium. The content of the low molecular weight organic compound composed of the above nonionic surfactant is 0.
1 to 5% by weight is preferable, and 0.1 to 2.5% by weight is more preferable. If the content of the low molecular weight organic compound is not proper, bleeding and show-through increase, which is not preferable.

Other low molecular weight organic compounds include cyclodextrin compounds, steroid compounds and calixarene compounds, so-called clathrate compounds.
In the ink composition of the present invention, one type of these compounds may be used alone, or two or more types may be used in combination.

Examples of cyclodextrins include cyclodextrins obtained by cyclically bonding a plurality of glucoses and derivatives thereof. Here, the cyclodextrin derivative means (1) a modified cyclodextrin obtained by subjecting cyclodextrin to a desired chemical modification, and (2) a polymer formed by bonding molecules of a plurality of cyclodextrins. .

These cyclodextrins have the property that the inside of the ring is hydrophobic and the outside is hydrophilic. The number of glucose constituting cyclodextrin is not particularly limited, but generally 6
, 7 or 8, specifically, a cyclodextrin in which glucose is bound in a ring, that is, α-
Cyclodextrin, β-cyclodextrin and γ
— Cyclodextrin. These cyclodextrins are preferred because they are readily available.

Examples of the modified cyclodextrin include those represented by the general formula (1):

[0043]

[Chemical 1]

A modified-β-cyclodextrin represented by the formula (wherein R represents a hydrogen atom, an alkyl group or an amino group) can be mentioned. In the general formula (1), one of the plurality of hydroxyl groups is chemically modified, but two or more hydroxyl groups may be chemically modified. Further, the substituent R may be other than the above.

Further, the cyclodextrin polymer is
(1) A polymer formed by condensation polymerization of hydroxyl groups between cyclodextrin molecules and (2) molecules of cyclodextrin have chemical structures derived from the outside (for example, a cross-linking structure by a cross-linking agent). Means a polymer bound through. The number of cyclodextrins forming the polymer is not particularly limited, but those industrially producible are preferable.

The cyclodextrin polymer may be, for example, a modified -β- represented by the above general formula (1).
Cyclodextrin

[0047]

[Chemical 2]

When expressed as, general formula (2) or general formula (3)

[0049]

[Chemical 3]

[In the formula, R ¹ and R ² are —S—S— (disulfide bond), —O— (ether bond) or —C _n H in which a hydrogen atom may be partially substituted with an amino group. _2n −
(Alkyl chain: n is an arbitrary integer of 1 or more)], and a dimer of β-cyclodextrin

Examples of the steroids include compounds having a perhydrocyclopentaphenanthrene ring (steroids) and their derivatives. Here, the steroid derivative is a compound having a steroid skeleton including (1) a side chain-attached cholestane or coprostane, and (2) a steroid alcohol (sterol) or a hydroxy acid, which is a desired chemistry for the steroid. It means a modified steroid or the like obtained by modification.

These steroids have the property that the ring is hydrophobic, and the hydroxyl group and the like bonded to the ring are hydrophilic, and the pigments are clathrated when they overlap each other in layers. . As such steroids, bile acid, which is one of the hydroxy acids of steroids, and derivatives thereof are preferable because they are easily available.

As the bile acid and its derivative, for example,
For example, the structural formula R represented by the following structural formula group (4)₁~ R_FourTo
More than 1,000 compound groups (R₁×
R₂× R ₃× R_Four) Is mentioned. Generally, bile acid
What steroids are structural formula R in structural formula group (4)
₁Skeletal isomers represented by ((A) and (B)), structure
Formula R₂Number and position of hydroxyl groups in the skeleton
((I) to (VIII)), structural formula R₃Side chain carbon represented by
Number ((1) to (5)) and structural formula R_FourSensory represented by
A specific compound depending on the combination of the groups ((a) to (j))
Things are expressed. For example, well known as bile acid
Cholic acid is represented by (A-I-3-a)
It is one of the compounds that are particularly preferable as the compounds.

[0054]

[Chemical 4]

Examples of the calixarene include a cyclic compound (calixarene) obtained by reacting formaldehyde with a phenol derivative and its derivative. The calixarene is known to be a tetramer from calix [4] arene to decameric. Here, the derivative of calixarene means a modified calixarene or the like obtained by subjecting calixarene to desired chemical modification.

These calixarenes have the property that the ring having a flexible structure is hydrophobic and the inside (and the outside) of the ring is hydrophilic. Such calixarenes include calix [6] arene which is a hexamer and calix [8] which is an octamer.
Arenes and derivatives thereof, such as p-sulfonic acid hexasodium salt and p-sulfonic acid octasodium salt, are preferred because they are easily available.

Examples of the calixarene and its derivative include those represented by the general formula (5):

[0058]

[Chemical 5]

(Wherein R ₀ represents a hydrogen atom, an alkyl group, a nitro group, or the like), a calix [4] arene and a derivative thereof, a general formula (6):

[0060]

[Chemical 6]

(Wherein R ₀ represents a hydrogen atom, an alkyl group, a nitro group or the like, and n ₀ represents an arbitrary integer of 0 or more), a calixarene or a derivative thereof, which is a pentamer or more, A general formula (7), which is a type of modified calixarene:

[0062]

[Chemical 7]

(In the formula, m represents an arbitrary integer of 1 or more,
X represents an arbitrary integer of 0 or more), and calixarene-p-sulfonic acid sodium salt.

The calixarene-p-sulfonic acid sodium salt represented by the general formula (7) is an anhydride when X is 0 and a hydrate when X is 1 or more. Also,
When m is 3, it is a calix [6] arene-p-sulfonic acid hexasodium salt, and when m is 5, it is a calix [8] arene-p-sulfonic acid octasodium salt. Among the above calixarenes, calix [8] arene-p-sulfonic acid octasodium salt anhydride is particularly preferable.

The content of the above low molecular weight organic compound is
0.1-40 weight% is preferable and 1-20 weight% is more preferable. When the content of the low molecular weight organic compound is within the above range, the ink composition is excellent in storage stability (light resistance / heat resistance), recording characteristics and fixing property to a medium, and is also capable of recording with excellent water resistance. The thing is obtained. If the content of the low molecular weight organic compound is not proper, bleeding and show-through increase, which is not preferable.

An oligomer compound can be used as the organic compound having a hydrophilic site and a hydrophobic site in the molecule. The oligomer compound plays an important role in high-chroma color development of the crystalline color organic pigment after being fixed on paper, and at the same time, greatly contributes to ensuring scratch resistance. Also,
When the crystalline color organic pigment has insufficient hydrophilicity, it also functions as a dispersant.

From this, an oligomer compound having a carboxyl group and an acid value of 50 to 300 (preferably 80 to 250) is preferably used. Further, it contains 35% or more of styrene units and / or α-methylstyrene units and has a weight average molecular weight of 25,000 or less, preferably 2,000 to 20,000, more preferably 2,500.
Polymers of up to 15,000 are preferably used.

Such oligomer compounds include styrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-acrylic acid-
Acrylic acid ester (alkyl ester of ₁ -C about ₄ C, hereinafter the same) copolymer, styrene - methacrylic acid copolymer, styrene - methacrylic acid - acrylic acid ester copolymers can be mentioned polyvinyl alcohol, polyvinyl Pyrrolidone and the like are also used.

Such a continuous bulk polymerization type acrylic oligomer has, for example, a weight average molecular weight of 10,000.
Jonc with 0 to 20,000 and an acid value of 200 or more
ryl67,690 (manufactured by Johnson Polymer Co.) is preferable. When the weight average molecular weight is out of the above range, it is difficult to secure dispersion stability, which is not preferable.

Further, it has a structure in which molecules are regularly arranged, having a portion having a functional group capable of hydrogen bonding or a covalent bond with the functional group of the pigment at the terminal or in the middle of the molecule, and a hydrophilic group at the terminal of the molecule. It is also possible to use a regulated polymerization type water-soluble oligomer compound including alternating copolymerization and block copolymerization. The regulated polymerization type water-soluble oligomer compound is not particularly limited as long as it gives high color saturation of the crystalline color organic pigment and fixability to the medium. Specifically, Solspers S2000, S12000, S22
000, S24000GR, S13240 (manufactured by Zeneca) and the like.

In the ink composition of the present invention, one of the above water-soluble oligomer compounds may be used alone, or two or more thereof may be used in combination. Its content is 1 to 1
0 wt% is preferable, and 2 to 8 wt% is more preferable. When the content is out of the above range, problems occur in dispersion stability, which is not preferable.

Other polymers, such as water-soluble polymers, are not preferable because they have poor dispersion stability and are not practical when combined with the crystalline color organic pigment of the present invention.

By further adding a specific penetrant to the ink composition of the present invention, it becomes possible to control and optimize the penetrability of the medium, and the crystalline color organic pigment is
The dullness of color due to sinking in the media is suppressed. In particular, such a penetrating agent plays an important role in plain paper not only to accelerate the drying property but also to prevent bleeding and efficiently fix the crystalline color organic pigment particles on the fiber surface of the paper.

The amount of penetrant added to the ink composition is 0.
It is about 1 to 5% by weight, preferably 0.5 to 4% by weight. If the amount of penetrant added is outside the above range,
This is not preferable because the drying property and the effect of preventing bleeding deteriorate.

Preferred examples of penetrants are ethylene glycol-n-butyl ether, diethylene glycol-n-butyl ether, triethylene glycol-n-.
Butyl ether, propylene glycol-n-butyl ether, glycol ethers such as dipropylene glycol-n-butyl ether, anion type ammonium salt of perfluoroalkylsulfonic acid, potassium salt of perfluoroalkylsulfonic acid, potassium salt of perfluoroalkylcarboxylic acid, Or nonionic perfluoroalkyl polyoxyethylene ethanol,
Fluorosurfactants such as perfluoroalkylalkoxylates and fluorinated alkyl esters, and modified silicones such as polyether modified silicone oil and hydrophilic special modified silicone oil are listed, but they have the function of lowering the surface tension. If it is a thing, it will not be limited to these.

Further, in order to control the permeability in addition to the above-mentioned penetrant, it is preferable to add a surfactant, particularly a nonionic surfactant, to the ink composition. The amount of the surfactant added to the ink composition is about 0.1 to 5% by weight,
It is preferably 0.5 to 4% by weight. If the amount of the surfactant added is outside the above range, bleeding and show-through increase, which is not preferable. Cationic surfactants and anionic surfactants are not preferable because, in combination with the colorant of the present invention, they easily foam, the dispersion stability is likely to deteriorate, and show-through tends to be large.

Preferred examples of the nonionic surfactant include alkyl ether type such as polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene cetyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl. Examples thereof include alkylphenol type such as ether, alkyl ester type such as polyoxyethylene monostearate, sorbitan ester type such as sorbitan monostearate and sorbitan monolaurate, and sorbitan ester type such as polyoxyethylene sorbitan monolaurate.

In addition to the organic pigment of the present invention, the ink composition of the present invention preferably contains a pH adjusting agent, a clogging preventing agent, a wetting agent and the like.

Preferred examples of the pH adjusting agent are urea and
2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3
-Dimethyl-imidazolidinone, diethanolamine,
A nitrogen-containing organic solvent such as triethanolamine may be used. These nitrogen-containing organic solvents also function as a clogging preventive agent when the ink is dried, and are effectively used. The amount of the nitrogen-containing organic solvent added to the ink composition is 1 to 10% by weight.
It is about 2 to 8% by weight, preferably.

The wetting agent also contributes to the improvement of the storage stability of the ink composition, the recording characteristics and the fixing property to the medium. Further, like the nitrogen-containing organic solvent, it also functions as an agent for preventing clogging of nozzles and orifices due to ink drying. The amount of the wetting agent added to the ink composition is 0.5 to 4
It is about 0% by weight, preferably 3 to 10% by weight.

Preferred examples of the wetting agent include diethylene glycol, polyethylene glycol, polypropylene glycol, tetrapropylene glycol, pentaethylene glycol, hexaethylene glycol, heptaethylene glycol, octaethylene glycol, ethylene glycol, propylene glycol, butylene glycol and triethylene. Glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol,
Examples include trimethylolethane and trimethylolpropane. According to a preferred embodiment of the present invention, 3
A polyhydric alcohol having a valency or more (for example, glycerin, diglycerin), and polyglycerin having a high hydrophilic-lipophilic balance (HLB) can be used, and the addition amount thereof is 2 to 20
It is about wt%, and its addition produces a remarkable effect.

In addition to the above wetting agent, it is preferable to add a low boiling point organic solvent to the ink composition. The amount of the low boiling point organic solvent added to the ink composition is 0.5 to 10
It is about wt%, preferably 1.5 to 6 wt%.

Preferred examples of the low boiling point organic solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and t.
Examples thereof include primary, secondary and tertiary alcohols such as ert-butanol, iso-butanol and n-pentanol, and primary alcohols are particularly preferable.

To the ink composition of the present invention, an appropriate modifier may be added, if necessary, in order to improve various physical properties of the ink. As the physical property adjusting agent, for example,
Viscosity modifiers, fungicides, preservatives and the like can be mentioned.

The ink composition of the present invention can be prepared by dispersing or mixing each of the above components in water by a suitable method. As a method of dispersing the crystalline color organic pigment of the present invention in an agglomerated state into fine particles having a volume average particle size defined in the present invention, a Dynomill dispersion method, a paint shaker dispersion method, a ball mill dispersion method, an attritor dispersion method, A usual method such as a sand mill dispersion method, a bead mill dispersion method or an ultrasonic dispersion method can be adopted.

According to the present invention, recording with high color density can be realized, and at the same time, vivid color reproduction (high color recording) can be obtained by controlling the light scattering of the coloring material particles, and when recording on plain paper. However, it is possible to obtain a record with very little blurring and show-through. In particular, the above effect is remarkably exhibited by using an organic pigment whose coloring material particles are hydrophilically modified by chemically and / or physically modifying the surface thereof. Further, according to the present invention, the dispersion stability and storage stability of the ink composition are also improved. Furthermore, addition of the oligomer compound achieves high saturation and high scratch resistance, and also improves storage stability of the ink composition.

By using the ink composition of the present invention, extremely high quality recording can be realized, and a recording apparatus using the same can be obtained. That is, as the pigment, not only the three primary colors of yellow pigment, magenta pigment, and cyan pigment, but also the transparency of the blue pigment, the green pigment, and the complementary color of the red pigment are high, and an ink composition that does not bleed onto plain paper can be realized. Therefore, it is possible to provide a three-color or six-color ink composition and a recording apparatus using the same. A known device such as an inkjet printer can be used as the recording device.

[0088]

EXAMPLES The present invention will be described more specifically based on Production Examples, Comparative Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Production Examples and Examples.

The hydrophilic state of the hydrophilic pigments obtained in Production Examples 1 to 9 was measured by measuring the contact angle of water with an automatic contact angle meter (Model CA-V) manufactured by Kyowa Interface Science Co., Ltd. evaluated.

(Production Example 1) CI Pigment Yellow 74 powder was placed in a glow discharge plasma device (electrode diameter 100 mm, distance between electrodes 50 mm), and oxygen gas pressure was 30 mP.
a, exposure treatment in reactive plasma was performed for 15 minutes under conditions of glow discharge power of 30 W to obtain a hydrophilic pigment. IR
The treated pigment powder was molded into pellets using a tablet molding machine, and the contact angle of water was measured. As a result, water droplets immediately penetrated. From this, it was confirmed that the pigment surface had an extremely high affinity, that is, the pigment was rendered hydrophilic by the above treatment.

(Production Examples 2-3) Instead of CI Pigment Yellow 74 as a pigment, CI Pigment Red 12
A hydrophilic pigment was obtained in the same manner as in Production Example 1 except that 2 and CI Pigment Blue 15: 3 were used.

(Production Example 4) CI Pigment Yellow 128 powder was placed in a vacuum chamber, the interior of the vacuum chamber was evacuated, and then oxygen gas was filled, and a low pressure mercury lamp (λ: 185 nm) was passed through a quartz glass window. Irradiate for 30 minutes. The treated pigment powder was molded into pellets using an IR tableting machine, and the contact angle of water was measured. As a result, water droplets instantly penetrated. From this, it was confirmed that the pigment surface had an extremely high affinity, that is, the pigment was rendered hydrophilic by the above treatment.

(Production Examples 5 to 6) As a pigment, CI Pigment Red 2 was used instead of CI Pigment Yellow 128.
02 and CI Pigment Blue 15: 3 were used, respectively, to obtain a hydrophilic pigment in the same manner as in Production Example 4.

(Production Example 7) CI Pigment Yellow 15 was added to about 100 g of concentrated sulfuric acid (98%) cooled to about 4 ° C.
5 g of 1 was added, and the mixture was stirred for 1 hour and then slowly dropped into water at 0 ° C. and stirred to obtain a hydrophilic pigment. Using an IR tablet press, the treated pigment powder was molded into pellets, and the contact angle of water was measured. As a result, it was confirmed that the pigment was extremely well-adapted to water, that is, that the pigment was hydrophilized by the above treatment. did it.

(Production Examples 8 to 9) Concentrated sulfuric acid was heated to 100 ° C., and CI Pigment Red 149 and CI were used as pigments.
A hydrophilic pigment was obtained in the same manner as in Production Example 7 except that Pigment Cyan 15: 3 was used.

(Comparative Production Example) As a pigment, a pigment having a relatively low light resistance (CI Pigment Yellow 17, CI Pigment Red 23, etc.) was treated in the same manner as in Production Example 1, Production Example 4 and Production Example 7. Even in the surface modification technique described above, the hue was greatly changed, and it was not possible to obtain the hydrophilized pigment that can be used in the present invention.

Electrophoretic light scattering photometer ELS-8000 manufactured by Otsuka Electronics Co., Ltd. was used, in which the particle size of the crystalline color organic pigment in the ink compositions obtained in Examples and Comparative Examples was taken as the volume average particle size (nm). Was measured using.
In addition, the ink compositions obtained in Examples 1 to 3 were dried and solidified, and the X-ray diffraction spectrum of the dried solid matter was measured by a powder X-ray diffractometer MXP-18 (X manufactured by Mac Science Co., Ltd.).
Radiation source: CuKα = 0.15405 nm).

[0098] (Example 1) Pigment C.I. Pigment Yellow 74 4% by weight Sorbitan monostearate 0.2% by weight Sols Perth 2000 3% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Deionized water remaining

The above components except n-propanol, urea, dipropylene glycol, and tetrapropylene glycol were mixed, and the mixture was mixed with a zirconia bead having a diameter of 1 mm by a paint conditioner device (manufactured by Red Level Co.).
After time-dispersion treatment to remove the zirconia beads, the remaining components were mixed and filtered through a 0.45 μm membrane filter to obtain an ink composition.

The volume average particle diameter of the pigment in the obtained ink composition was 115 mm. Further, the X-ray diffraction spectrum of the dried product of the obtained ink composition was measured. As shown in FIG. 2, the spectrum has a black angle (2θ ±
0.2 °) has major diffraction peaks at 11.9 °, 25.6 ° and 26.8 °, and the maximum diffraction peak is 11.9 °.
And 26.8 ° (almost the same intensity), its half-width (F
WHM) was 0.32 °.

[0101] (Example 2) Pigment C.I. Pigment Red 122 3.5% by weight Sorbitan monostearate 0.2% by weight Sols Perth 20000 3% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Deionized water remaining

The above components except n-propanol, urea, dipropylene glycol, and tetrapropylene glycol were mixed, and the mixture was mixed with a zirconia bead having a diameter of 1 mm by a paint conditioner device (manufactured by Red Level Co.).
After time-dispersion treatment to remove the zirconia beads, the remaining components were mixed and filtered through a 0.45 μm membrane filter to obtain an ink composition.

The volume average particle diameter of the pigment in the obtained ink composition was 91 mm. Further, the X-ray diffraction spectrum of the dried product of the obtained ink composition was measured. The spectrum has a black angle (2θ ± 0.
2 °) has major diffraction peaks at 5.6 ° and 11.2 °, and the maximum diffraction peak is 5.6 °, and the half width thereof is 0.
It was 29 °.

[0104] (Example 3) Pigment C.I. Pigment Blue 15: 3 3.5% by weight Sorbitan monostearate 0.2% by weight Sols Perth 20000 3% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Deionized water remaining

The above components except n-propanol, urea, dipropylene glycol, and tetrapropylene glycol were mixed, and the mixture was mixed with a zirconia bead having a diameter of 1 mm using a paint conditioner device (manufactured by Red Level Co.).
After performing a dispersion treatment for 0 hour to remove the zirconia beads, the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition.

The volume average particle diameter of the pigment in the obtained ink composition was 84 mm. Further, the X-ray diffraction spectrum of the dried product of the obtained ink composition was measured. The spectrum has a black angle (2θ ± 0.
2 °) 7.0 °, 9.2 °, 18.2 ° and 18.6
There is a major diffraction peak at ° and the maximum diffraction peak is 9.2.
The full width at half maximum was 0.28 °.

Using an applicator, a fixed amount of each of the ink compositions obtained in Examples 1 to 3 was applied to coated paper, and the spectral reflection spectrum thereof was measured using X-Rite 938 manufactured by Nippon Planographic Equipment Co., Ltd. did. The obtained results are shown in FIGS. FIG. 1 shows an ideal spectral reflection spectrum of the three primary colors, but in reality, there is no colorant having such ideal characteristics, and the curve is as shown in the figure. In general, the spectral reflection characteristics (spectral absorption characteristics of the pigment) greatly change at the ideal absorption wavelength of the spectral reflection spectrum.

[0108] (Example 4) Hydrophilizing Pigment of Production Example 1 C.I. Pigment Yellow 74 3.5% by weight Polyoxyethylene sorbitan monolaurate 0.1% by weight Triethylene glycol-n-butyl ether 5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components except triethylene glycol-n-butyl ether, n-propanol and diethylene glycol were mixed and dispersed by irradiating them with ultrasonic waves of 20 KHz for 1 hour using an ultrasonic crusher (manufactured by Nippon Seiki Seisakusho Co., Ltd.). Let Then, the remaining components are mixed by stirring,
An ink composition was obtained by filtering with a 0.45 μm membrane filter. When the volume average particle size of the crystalline color organic pigment in the obtained ink compositions was measured in the same manner as in Examples 1 to 3, it was 60 nm. In addition, Examples 1 to 3
When the X-ray diffraction spectrum was measured in the same manner as above, the full width at half maximum of the maximum diffraction peak was 0.27 °.

[0110] (Example 5) Hydrophilicizing pigment C.I. Pigment Red 122 3.5% by weight of Production Example 2 Polyoxyethylene sorbitan monolaurate 0.1% by weight Triethylene glycol-n-butyl ether 5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components except for triethylene glycol-n-butyl ether, n-propanol and diethylene glycol were mixed and dispersed by irradiating them with ultrasonic waves of 20 KHz for 1 hour using an ultrasonic crusher (manufactured by Nippon Seiki Seisakusho Co., Ltd.). Let Then, the remaining components are mixed by stirring,
An ink composition was obtained by filtering with a 0.45 μm membrane filter. When the volume average particle size of the crystalline color organic pigment in the obtained ink compositions was measured in the same manner as in Examples 1 to 3, it was 61 nm. In addition, Examples 1 to 3
When the X-ray diffraction spectrum was measured in the same manner as above, the full width at half maximum of the maximum diffraction peak was 0.28 °.

[0112] (Example 6) Hydrophilizing Pigment of Production Example 3 C.I. Pigment Blue 15: 3 3.5% by weight Polyoxyethylene sorbitan monolaurate 0.1% by weight Triethylene glycol-n-butyl ether 5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components except triethylene glycol-n-butyl ether, n-propanol and diethylene glycol were mixed and dispersed by irradiating them with ultrasonic waves of 20 KHz for 2 hours using an ultrasonic crusher (Nippon Seiki Seisakusho Co., Ltd.). Let Then, the remaining components are mixed by stirring,
An ink composition was obtained by filtering with a 0.45 μm membrane filter. When the volume average particle diameter of the crystalline color organic pigment in the obtained ink compositions was measured in the same manner as in Examples 1 to 3, it was 83 nm. In addition, Examples 1 to 3
When the X-ray diffraction spectrum was measured in the same manner as above, the full width at half maximum of the maximum diffraction peak was 0.27 °.

[0114] (Example 7) Hydrophilizing Pigment of Production Example 4 C.I. Pigment Yellow 128 3.5% by weight Surfynol 485 0.5% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Perfluoroalkyl polyoxyethylene ethanol 0.2% by weight Deionized water remaining

The above components except for n-propanol, urea, dipropylene glycol, tetrapropylene glycol, and perfluoroalkyl polyoxyethylene ethanol were mixed, and the mixture was dried with a Dynomill (made by Willy E. Bakofen (WAB)) to give a diameter of 1 mm. A dispersion treatment was performed together with the zirconia beads for 10 hours to remove the zirconia beads, and then the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured in the same manner as in Examples 1 to 3, 11
It was 5 nm. In addition, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.29 °.

[0116] (Example 8) Hydrophilizing pigment C.I. Pigment Red 202 3.5% by weight of Production Example 5 Surfynol 485 0.5% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Perfluoroalkyl polyoxyethylene ethanol 0.2% by weight Deionized water remaining

The above components except for n-propanol, urea, dipropylene glycol, tetrapropylene glycol, and perfluoroalkyl polyoxyethylene ethanol were mixed, and the mixture was dried with a Dynomill (manufactured by Willy E. Bakkofen (WAB)) to a diameter of 1 mm. A dispersion treatment was performed together with the zirconia beads for 10 hours to remove the zirconia beads, and then the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured in the same manner as in Examples 1 to 3, it was 10
It was 8 nm. Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.30 °.

[0118] (Example 9) Hydrophilicizing Pigment of Production Example 6 C.I. Pigment Blue 15: 3 3.5% by weight Surfynol 485 0.5% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Perfluoroalkyl polyoxyethylene ethanol 0.2% by weight Deionized water remaining

The above components except for n-propanol, urea, dipropylene glycol, tetrapropylene glycol and perfluoroalkyl polyoxyethylene ethanol were mixed, and the mixture was dried with Dynomill (manufactured by Willy E. Bakkofen (WAB)) to obtain a product having a diameter of 1 mm. A dispersion treatment was performed together with the zirconia beads for 10 hours to remove the zirconia beads, and then the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured in the same manner as in Examples 1 to 3, 12
It was 0 nm. Further, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.27 °.

[0120] (Example 10) Hydrophilic pigment C.I. Pigment Yellow 151 of Production Example 2.0 2.0% by weight α-Cyclodextrin 10% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Glycerin 7% by weight Ethylene glycol-n-butyl ether 4% by weight Triethanolamine 0.5% by weight Deionized water remaining

Mixing the above components except n-propanol, diethylene glycol, glycerin, ethylene glycol-n-butyl ether, triethanolamine,
Using an ultrasonic crusher (Nippon Seiki Co., Ltd.) 2
Ultrasonic waves of 0 KHz were irradiated for 1 hour to disperse. Subsequently, the remaining components were mixed by stirring and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle size of the crystalline color organic pigment in the obtained ink composition was measured in the same manner as in Examples 1 to 3, it was 75
was nm. Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.31 °.

[0122] (Example 11) Hydrophilicizing Pigment of Production Example 8 C.I. Pigment Red 149 2.0% by weight α-Cyclodextrin 10% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Glycerin 7% by weight Ethylene glycol-n-butyl ether 4% by weight Triethanolamine 0.5% by weight Deionized water remaining

Mixing the above components except n-propanol, diethylene glycol, glycerin, ethylene glycol-n-butyl ether, triethanolamine,
Using an ultrasonic crusher (Nippon Seiki Co., Ltd.) 2
Ultrasonic waves of 0 KHz were irradiated for 1 hour to disperse. Subsequently, the remaining components were mixed by stirring and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured in the same manner as in Examples 1 to 3, it was 93
was nm. In addition, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.29 °.

[0124] (Example 12) Hydrophilizing Pigment of Production Example 9 C.I. Pigment Blue 15: 3 2.0% by weight α-Cyclodextrin 10% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Glycerin 7% by weight Ethylene glycol-n-butyl ether 4% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components except n-propanol, diethylene glycol, glycerin, and ethylene glycol-n-butyl ether were mixed and irradiated with 20 KHz ultrasonic waves for 1 hour using an ultrasonic crusher (manufactured by Nippon Seiki Seisakusho Co., Ltd.). Dispersed. Subsequently, the remaining components were mixed by stirring and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle size of the crystalline color organic pigment in the obtained ink compositions was measured in the same manner as in Examples 1 to 3, it was 103 nm. Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.28 °.

[0126] (Example 13) Hydrophilic pigment C.I. Pigment Yellow 151 of Production Example 2.0 2.0% by weight Joncryl67 2.5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Glycerin 7% by weight Ethylene glycol-n-butyl ether 4% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components except n-propanol, diethylene glycol, glycerin, and ethylene glycol-n-butyl ether were mixed and irradiated with ultrasonic waves of 20 KHz for 1 hour using an ultrasonic crusher (manufactured by Nippon Seiki Seisakusho Co., Ltd.). Dispersed. Subsequently, the remaining components were mixed by stirring and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle diameter of the crystalline color organic pigment in the obtained ink compositions was measured in the same manner as in Examples 1 to 3, it was 79 nm. In addition, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.29 °.

[0128] (Example 14) Hydrophilicizing Pigment of Production Example 8 C.I. Pigment Red 149 2.0% by weight Joncryl 67 2.5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Glycerin 7% by weight Ethylene glycol-n-butyl ether 4% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components except n-propanol, diethylene glycol, glycerin and ethylene glycol-n-butyl ether were mixed, and ultrasonic waves of 20 KHz were irradiated for 2 hours using an ultrasonic crusher (manufactured by Nippon Seiki Seisakusho Co., Ltd.). Dispersed. Subsequently, the remaining components were mixed by stirring and filtered with a 0.45 μm membrane filter to obtain an ink composition. . When the volume average particle size of the crystalline color organic pigment in the obtained ink compositions was measured in the same manner as in Examples 1 to 3, it was 96 nm. Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.30 °.

[0130] (Example 15) Hydrophilizing Pigment of Production Example 9 C.I. Pigment Blue 15: 3 2.0% by weight Joncryl 67 2.5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Glycerin 7% by weight Ethylene glycol-n-butyl ether 4% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components except n-propanol, diethylene glycol, glycerin, and ethylene glycol-n-butyl ether were mixed, and ultrasonic waves of 20 KHz were irradiated for 2 hours using an ultrasonic crusher (manufactured by Nippon Seiki Seisakusho Co., Ltd.). Dispersed. Subsequently, the remaining components were mixed by stirring and filtered with a 0.45 μm membrane filter to obtain an ink composition. It was 101 nm when the volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured like Example 1-3. Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.28 °.

[0132] (Comparative Example 1) Pigment C.I. Pigment Yellow 74 4.5% by weight Sols Perth 27000 3% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Deionized water remaining

The above components other than n-propanol, urea, dipropylene glycol and tetrapropylene glycol were mixed and mixed together with glass beads having a diameter of 0.8 mm by a paint conditioner device (manufactured by Red Level Co.).
After dispersion treatment for 0 hour to remove the glass beads, the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. The volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured in the same manner as in Examples 1 to 3, and it was 36 nm.
Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.76 °.

[0134] (Comparative example 2) Pigment C.I. Pigment Red 122 3.5% by weight Sols Perth 27000 2.5% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Deionized water remaining

The above components other than n-propanol, urea, dipropylene glycol and tetrapropylene glycol were mixed together and mixed with glass beads having a diameter of 0.8 mm using a paint conditioner device (manufactured by Red Level Co.).
After dispersion treatment for 0 hour to remove the glass beads, the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle size of the crystalline color organic pigment in the obtained ink compositions was measured in the same manner as in Examples 1 to 3, it was 35 nm.
Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the half-width of the maximum diffraction peak was 0.59 °.

[0136] (Comparative example 3) Pigment C.I. Pigment Blue 15: 3 3.5% by weight Sols Perth 27000 2.5% by weight n-Propanol 2% by weight Urea 5% by weight Dipropylene glycol 5% by weight Tetrapropylene glycol 5% by weight Deionized water remaining

The above components other than n-propanol, urea, dipropylene glycol and tetrapropylene glycol were mixed and mixed together with glass beads having a diameter of 0.8 mm by a paint conditioner device (manufactured by Red Level Co.).
After dispersion treatment for 0 hour to remove the glass beads, the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. When the volume average particle size of the crystalline color organic pigment in the obtained ink compositions was measured in the same manner as in Examples 1 to 3, it was 31 nm.
Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the full width at half maximum of the maximum diffraction peak was 0.60 °.

[0138] (Comparative example 4) Hydrophilized pigment C.I. Pigment Yellow 74 2.5% by weight of Production Example 1 Triethylene glycol-n-butyl ether 5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components other than triethylene glycol-n-butyl ether, n-propanol and diethylene glycol were mixed and dispersed for 24 hours with glass beads having a diameter of 0.8 mm by a paint conditioner device (manufactured by Red Level Co.) to obtain glass. After removing the beads, the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. Example 1
The volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured in the same manner as in
Met. Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the half-width of the maximum diffraction peak was 0.78 °.

[0140] (Comparative example 5) Hydrophilicizing pigment C.I. Pigment Red 122 3.5% by weight of Production Example 2 Triethylene glycol-n-butyl ether 5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components other than triethylene glycol-n-butyl ether, n-propanol and diethylene glycol were mixed, and dispersed for 24 hours with glass beads having a diameter of 0.8 mm by a paint conditioner device (manufactured by Red Level Co.) to obtain glass. After removing the beads, the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. Example 1
~ 3, the volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured and found to be 35 nm.
Met. Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the half-width of the maximum diffraction peak was 0.61 °.

[0142] (Comparative example 6) Hydrophilizing Pigment of Production Example 3 C.I. Pigment Blue 15: 3 3.5% by weight Triethylene glycol-n-butyl ether 5% by weight n-Propanol 2% by weight Diethylene glycol 10% by weight Triethanolamine 0.5% by weight Deionized water remaining

The above components other than triethylene glycol-n-butyl ether, n-propanol and diethylene glycol were mixed, and dispersed for 24 hours with glass beads having a diameter of 0.8 mm by a paint conditioner device (manufactured by Red Level Co.) to obtain glass. After removing the beads, the remaining components were mixed and filtered with a 0.45 μm membrane filter to obtain an ink composition. Example 1
The volume average particle diameter of the crystalline color organic pigment in the obtained ink composition was measured in the same manner as in No. 3 to 33 nm.
Met. Moreover, when the X-ray diffraction spectrum was measured in the same manner as in Examples 1 to 3, the half-width of the maximum diffraction peak was 0.80 °.

The properties of the ink compositions obtained in Examples and Comparative Examples were evaluated by the methods shown below.

(A) Reflection Density A fixed amount (1.0 ml) of each ink composition was sampled, and an applicator-coated special coated paper (RW-P4A4) was dried to obtain a reflection density measurement sample. It was The reflection density of the obtained sample was measured using a densitometer RD-918 (manufactured by Macbeth). A value of 1.40 or more was evaluated as good.

(B) In the same manner as the sample for measuring the show-through reflection density, the ink composition coated on plain paper (SF-4AM3) was dried to obtain a sample for show-through evaluation. The reflection density of the back surface (surface not coated with the ink composition) of the obtained sample was measured using a densitometer RD-918 (manufactured by Macbeth Co.) to evaluate the degree of show-through. When the value was 0.12 or less, it was evaluated that double-sided printing was possible.

(C) Color characteristics A spectrocolorimeter (Spectr
Odensitometer) X-Rite 938 (manufactured by Nippon Planographic Equipment Co., Ltd.) was used to evaluate the color characteristics (lightness, chromaticity) in the L ^* a ^* b ^* color system. Color vividness (saturation C ^* )
Was calculated by the following equation.

[0148]

[Equation 1]

(D) Bleed characteristic An automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.) was diverted and a fixed amount of the ink composition (0.7 μl) was applied to plain paper (SF-4).
It was adhered to the AM3) surface, the spread (dot diameter) on the paper surface was measured, the standard deviation was determined as the standard of the circularity of the dot on the paper surface, and the bleeding characteristics were evaluated according to the following criteria. ◎: Spread of 1.5 mm or less ○: Spread of 2.5 mm or less ×: Spread of more than 2.5 mm (△): Standard deviation of 0.2 or more (poor circularity thing)

(E) Storage Stability Each ink composition (about 20 ml) was placed in a laboratory screw tube bottle and a storage test was carried out at 60 ° C. for 1 month. 1
Dynamic light scattering particle size distribution analyzer LB-500 after months
(Manufactured by Horiba Ltd.) was used to measure the particle size of the pigment. The rate of change was determined from the obtained results and the particle size measured in advance before the storage test, and the storage stability was evaluated according to the following criteria. ◎: Change rate of 15% or less ○: Change rate of 20% or less △: Change rate of 30% or less ×: Change rate of more than 30%

(F) Clogging property Ink jet printer PM760C (manufactured by Seiko Epson Corporation) was filled with the ink composition, and 1
After printing for a time, the printing operation was stopped. Subsequently, the ejection characteristics after the printer was left at room temperature for 1 day without capping the ink head were evaluated according to the following criteria. ◯: Printing is possible with no problems after 5 cleaning operations. Δ: Printing is possible after 6 to 11 cleanings. ×: Printing failure occurs even after 12 or more cleaning operations.

(G) Light resistance Light resistance tester Q-SUN Xenon Test Ch
Install the reflection density measurement sample on the amber, 0.3
ΔE was measured before and after irradiation with light of 5 W / m 2 (λ = 340 nm) for 300 hours. The above evaluation results are summarized in Table 2.

[0153]

[Table 2]

As is clear from this result, in the examples of the present invention, high reflection density and color vividness were obtained, bleeding and show-through on plain paper were small, and ejection stability and storage stability were also improved. It has been found that an excellent ink composition can be obtained.

[0155]

According to the present invention, the full width at half maximum (FWHM) of the diffraction line showing the maximum intensity in the X-ray diffraction spectrum is limited, and such a crystalline color organic pigment is strongly bonded to the crystalline color organic pigment. An ink using a conventional organic pigment while maintaining excellent light resistance by forming an ink composition from a specific organic compound having a hydrophilic site and a hydrophobic site that are bound by action in the molecule It is possible to overcome the problem that the density, which is a drawback of the composition, is difficult to appear and only a dull color can be reproduced. Also, particle size optimization
Not only the effect on the hue and vividness, but also the effect on the prevention of bleeding on plain paper is expected, and in particular, it shows an extremely high effect in combination with a penetrant. At the same time, the use of the crystalline color organic pigment having the optimized particle size in combination with a specific polymer also has a significant effect on the storage stability of the ink composition.

[Brief description of drawings]

FIG. 1 is an ideal spectral reflection spectrum of a coloring material and Example 1
It is a figure which shows the spectral reflection spectrum of the crystalline color organic pigment of (3).

FIG. 2 is an X-ray diffraction spectrum of the ink composition of the present invention (Example 1).

FIG. 3 is an X-ray diffraction spectrum of the ink composition of the present invention (Example 2).

FIG. 4 is an X-ray diffraction spectrum of the ink composition of the present invention (Example 3).

FIG. 5 is a schematic diagram showing a method for determining the maximum wavelength λ ₁ and the minimum wavelength λ ₂ of the measured values in the absorption wavelength region of the spectral reflection spectrum.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA05 EA13 FC02                 2H086 BA55 BA59 BA60                 4J039 AD09 AD10 AE11 BC09 BC20                       BE01 BE22 CA03 CA06 EA15                       EA16 EA17 EA35 EA36 EA38                       EA42 EA47 GA24

Claims (18)

[Claims] 1. A crystalline color organic pigment having a diffraction line showing the maximum intensity in an X-ray diffraction spectrum having a half width of 0.4 ° or less, and an organic compound having a hydrophilic site and a hydrophobic site in the molecule. An ink composition comprising as a main component. 2. The crystalline color organic pigment according to claim 1, wherein the crystalline color organic pigment has a volume average particle diameter in the range of 1/4 of the maximum wavelength of the desired absorption wavelength range to 1/10 of the minimum wavelength in the spectral reflection spectrum. Colorant. 3. A crystalline color organic pigments, the volume average particle diameter of the maximum wavelength lambda ₁ and the minimum range of the wavelength lambda ₂ of lambda _1/4 from lambda _2/10 of the measured absorption wavelength region in the spectral reflection spectrum The colorant according to claim 1, which has. 4. The crystalline color organic pigment has a black angle (2θ ± 0.2 °) of 11.9 ° in an X-ray diffraction spectrum using CuKα ray (0.154050 nm).
It has major diffraction peaks at 25.6 ° and 26.8 °, and the diffraction peak at 11.9 ° or 26.8 ° shows the maximum intensity, or the black angle (2θ ± 0.2 °)
A crystalline yellow pigment having major diffraction peaks at 11.1 ° and 27.0 °, showing the maximum intensity at the diffraction peak at 27.0 °, and having a volume average particle diameter in the range of 40 to 125 nm. The ink composition according to any one of claims 1 to 3, which is 5. The crystalline color organic pigment has a black angle (2θ ± 0.2 °) of 5.6 ° and 1 in an X-ray diffraction spectrum using CuKα ray (0.154050 nm).
It has a major diffraction peak at 1.2 ° and has the above-mentioned 5.6 °
4. The ink composition according to any one of claims 1 to 3, which is a crystalline magenta pigment having a diffraction intensity of maximum intensity and a volume average particle size of 50 to 150 nm. 6. The crystalline color organic pigment has a black angle (2θ ± 0.2 °) of 7.0 ° in an X-ray diffraction spectrum using CuKα ray (0.154050 nm),
It has major diffraction peaks at 9.2 °, 18.2 °, and 18.6 °, and the diffraction peak at 9.2 ° shows the maximum intensity, or the black angle (2θ ± 0.2 °) 7.0 °,
A crystalline cyan pigment having major diffraction peaks at 9.1 ° and 18.2 °, showing the maximum intensity at the diffraction peak at 7.0 °, and having a volume average particle diameter in the range of 60 to 175 nm. The ink composition according to any one of claims 1 to 3, which is 7. The ink composition according to claim 1, wherein the crystalline color organic pigment is a pigment that is modified by chemical treatment and / or physical treatment to be hydrophilized. 8. The ink composition according to claim 7, wherein the chemical treatment and / or physical treatment is a treatment in which at least one hydrophilic group is chemically adsorbed and / or bound to the surface of the crystalline color organic pigment. object. 9. The content of the crystalline color organic pigment is 0.
The ink composition according to any one of claims 1 to 8, which is 1 to 10% by weight. 10. The organic compound having a hydrophilic site and a hydrophobic site in the molecule is a nonionic surfactant selected from sorbitan esters, sorbitan ester ethers and acetylene glycols. The ink composition according to any one of 1. 11. The ink composition according to claim 10, wherein the content of the organic compound having a hydrophilic site and a hydrophobic site in the molecule is 0.1 to 5% by weight. 12. An organic compound having a hydrophilic site and a hydrophobic site in the molecule is a cyclodextrin selected from α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and derivatives thereof, bile acid and The ink composition according to any one of claims 1 to 9, which is a compound selected from steroids selected from derivatives thereof and calixarenes selected from calixarenes and derivatives thereof. 13. The ink composition according to claim 12, wherein the content of the organic compound having a hydrophilic site and a hydrophobic site in the molecule is 0.1 to 40% by weight. 14. The organic compound having a hydrophilic site and a hydrophobic site in the molecule is a continuous bulk polymerization type water-soluble acrylic oligomer compound or a regulated polymerization type water-soluble oligomer compound, and their weight average molecular weight is 25. 1,000
The ink composition according to any one of claims 1 to 9, which is as follows. 15. The ink composition according to claim 14, wherein the content of the organic compound having a hydrophilic site and a hydrophobic site in the molecule is 1 to 10% by weight. 16. The ink composition according to claim 1, further comprising a penetrant, the content of which is 0.1 to 5% by weight. 17. The ink composition according to claim 16, wherein the penetrant is at least one selected from glycol ethers, fluorochemical surfactants and modified silicones. 18. The crystalline yellow organic pigment, the crystalline magenta pigment, and the crystalline cyan pigment are separately contained as the crystalline color organic pigments.
A recording apparatus, wherein the ink composition according to item 1 is used in combination.