WO2005066289A1 - Procede d'impression - Google Patents

Procede d'impression Download PDF

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Publication number
WO2005066289A1
WO2005066289A1 PCT/JP2004/019830 JP2004019830W WO2005066289A1 WO 2005066289 A1 WO2005066289 A1 WO 2005066289A1 JP 2004019830 W JP2004019830 W JP 2004019830W WO 2005066289 A1 WO2005066289 A1 WO 2005066289A1
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Prior art keywords
group
groups
ofthe
heterocyclic
dye
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PCT/JP2004/019830
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English (en)
Inventor
Toshiki Taguchi
Takashi Ozawa
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Fuji Photo Film Co., Ltd.
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Publication of WO2005066289A1 publication Critical patent/WO2005066289A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
    • B41M5/52—Macromolecular coatings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/0023—Digital printing methods characterised by the inks used
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/30—Inkjet printing inks
    • C09D11/32—Inkjet printing inks characterised by colouring agents
    • C09D11/328—Inkjet printing inks characterised by colouring agents characterised by dyes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
    • B41M5/52—Macromolecular coatings
    • B41M5/5218—Macromolecular coatings characterised by inorganic additives, e.g. pigments, clays
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
    • B41M5/52—Macromolecular coatings
    • B41M5/5236—Macromolecular coatings characterised by the use of natural gums, of proteins, e.g. gelatins, or of macromolecular carbohydrates, e.g. cellulose
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
    • B41M5/52—Macromolecular coatings
    • B41M5/5245—Macromolecular coatings characterised by the use of polymers containing cationic or anionic groups, e.g. mordants

Definitions

  • the present invention relates to an ink jet recording method excellent in image durability, including image stability under high humidity conditions.
  • the present invention relates to a recording ink (preferably an ink for ink jet recording) and a recording method (preferably an ink jet recording method) which can provide an image having an excellent hue and excellent storage properties under severe conditions.
  • ink jet printers have been widely used to print on paper, film, cloth, etc. at offices as well as at home.
  • Examples of ink jet recording method include a method which allows a piezoelectric element to give pressure that causes a droplet to be ejected, si method which comprises heating the ink to generate bubbles, causing a droplet to be ejected, a method involving the use of ultrasonic wave, and a method which uses electrostatic force to suck and discharge a droplet.
  • inks for these ink jet recording methods there are used aqueous inks, oil-based inks and solid (melt type) inks.
  • aqueous inks are mainly used from the standpoint of producibility, handleability, odor, safety, etc.
  • the dyes to be incorporated in these inks for ink jet recording are required to exhibit a high solubility in solvents, allow a high density recording and have a good hue and an excellent fastness to light, heat, air, water and chemical, a good fixability to recording materials (image-receiving materials), difficulty in running, an excellent preservability, no toxicity and a high purity and be available at a low cost.
  • dyes having a good cyan hue and an excellent weathering resistance have been keenly desired.
  • JP-A-6-24123, JP-A-6-152905 and JP-A-3-33298 describe a recording method in which spreading of dots is prevented when recording is performed to standard paper.
  • a first aim ofthe invention is to provide an ink jet recording method which is little subject to image bleeding even under high humidity conditions. It is therefore a second aim ofthe invention to provide a recording method (preferably an ink jet recording method) which exhibits a high ejection stability and can provide a high quality image having an excellent hue and excellent storage properties. It is another aim ofthe invention to provide a recording method (preferably an ink jet recording method) which exhibits a good ejection stability under severe conditions over an extended period of time and can provide an image having high storage properties.
  • the aforementioned first aim ofthe invention is accomplished by the following six constitutions of ink jet recording method.
  • An ink jet recording method comprising printing an ink with an ink on an image-receiving material, according to an image data, so as to form an image, wherein the ink includes: an anionic dye; and at least one of water and a water-soluble organic solvent, and wherein the anionic dye has three or more hydrogen-bonding functional groups.
  • the ink jet recording method as described in Clause (1) wherein a printing surface ofthe image- receiving material contains a compound having four or more hydrogen-bonding functional groups.
  • X 2 ⁇ , X 22 , X 2 3 and X 24 each independently represents -SO-Z2, -SO2-Z2, -SO2N 21R22, sulfo group, - CONR 21 R 22 or -COOR 21 in which Z 2 's each independently represents a substituted or unsubstituted alkyl, cycloalkyl, alkenyl, aralkyl, aryl or heterocyclic group and R 21 and R2 2 each independently represents a hydrogen atom or substituted or unsubstituted alkyl, cycloalkyl, alkenyl, aralkyl, aryl or heterocyclic group; Y 2 2, Y 23 and Y 24 each independently represents a monovalent substituent; a 2 ⁇ to a 4 and b 2 ⁇ to b 24 represent the number of the substituents X 2 ⁇ to X 24 and Y 2 ⁇ to Y 24 , respectively; a 2 ⁇ to a 24 each independently represents
  • a 31 represents a 5-membered heterocyclic group
  • G 3 , 21 and R 32 each independently represents a hydrogen atom, a halogen atom or an aliphatic group, aromatic group, heterocyclic group, cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, acyl group, hydroxyl group, alkoxy group
  • X5 1 to X5 4 , Y 51 to Y 5 8 and Ml have the same meaning as X 2 ⁇ to X 24 , Y 2 ⁇ to Y 24 and M in the general formula (1-2); and a 5 ⁇ to as 4 each independently represent an integer of 1 or 2.
  • the second aim ofthe invention is accomplished by the following constitutions (7) to (16).
  • a recording method which comprises ejecting ink drops onto a recording material (receiving material) according to a recording signal, the recording material comprising a support and an ink-receptive layer provided on the support, by using at least two color inks comprising a yellow ink and a magenta ink, so as to record an image on the recording material, wherein the percent bleeding ofthe recorded image upon storage ofthe recorded image under high humidity (defined in Clause (8)) is 30% or less.
  • the first embodiment ofthe invention will be furtlier described hereinafter.
  • the invention discloses a technique of preventing image bleeding.
  • an ink jet recording method comprising: printing, on an image-receiving material, an ink that includes: an anionic dye; and at least one of water and a water-soluble organic solvent, according to an image data to form an image, wherein the anionic dye has three or more hydrogen-bonding functional groups.
  • an ink jet recording method involving the use of an aqueous ink comprising a water-soluble dye dissolved in an aqueous solvent is mainly used both at home and office.
  • the aqueous dye which can be merely dissolved in water to form a uniform solution has a long history and thus can be used with techniques which have been accumulated on various molecular designs.
  • the aqueous ink jet recording method involves the use of an ink free of solid content such as pigment that forms a uniform solution and thus is most suitable for maintenance of desired ejection stability of nozzle, winch is the greatest assignment in ink jet recording.
  • the aqueous solvent has a high safety and a higher handleability than volatile solvent.
  • the aqueous ink jet method involves recording a water-soluble dye on an image- receiving material with a water-soluble solvent left in the ink, image bleeding is observed when the image thus printed is stored under high humidity conditions despite the coexistence of a dye fixing material (e.g., mordant). It was found that this problem becomes remarkable with a dye having a high water solubility.
  • a mutual interaction between dye and image-receiving material for dye fixing having a different mechanism from that of ordinary mordant is introduced.
  • the introduction of a bonding group comprising a plurality of hydrogen bonds in combination is effective for this purpose.
  • Hydrogen bond is developed when a hydrogen atom connected to an atom having a high polarity present in an organic functional group forms a false bond while being oriented among polar atoms present in the molecule or foreign molecules.
  • This hydrogen bond reference can be made to Motohiro Nishio, "Yuki Kagaku no Tameno Bunshikanryoku Nyumon (Introduction of Intermolecular Force for Organic Chemistry)", Scientific, Kodansha, 2000, pp. 21 - 25.
  • polar atom as used herein is meant to indicate an atom having a high electronegativity than that of carbon atom as calculated in terms of value proposed by L. Pauling.
  • Examples of such a polar atom include oxygen atom, sulfur atom, selenium atom, nitrogen atom, and phosphorus atom.
  • Examples of functional groups on the part of hydrogen donor capable of developing hydrogen bond include hydroxyl groups (including both alcoholic hydroxyl group and phenolic hydroxyl group), thio groups (including both alkylthio group and arylthio group), carboxyl groups, phosphoric acid groups, phosphone groups, carbonamide groups, sulfonamide groups, alkylcarbonamide groups, arylcarbonamide groups, alkylsulfonamide groups, arylsulfonamide groups, carbamoyl groups, sulfamoyl groups, alkylcarbamoyl groups, arylcarbamoyl groups, alkylsulfamoyl groups, arylsulfamoyl groups, phosphonamide groups, amino groups, heterocyclic groups having N-H bond (e.g., pyrazole group, imid
  • functional groups on the part of hydrogen atom acceptor there may be used groups containing polar atom except hydrogen atom.
  • these functional groups include ether groups, thioether groups, carbonyl groups, thiocarbonyl groups, amino groups, and nitrogen atom, oxygen atom and sulfur atom contained in heterocyclic group.
  • 4 or more, preferably 5 or more, more preferably 8 or more, particularly 10 or more such hydrogen-donating functional groups capable of developing hydrogen bonding properties are contained in one molecule.
  • amide-based groups e.g., carbonamide group, sulfonamide group, alkylcarbonamide group, arylcarbonamide group, alkylsulfonamide group, arylsul
  • mordant mutual interaction for the purpose of fixing dye, mordant mutual interaction, too, acts besides the hydrogen-bonding mutual interaction.
  • a compound containing a group having a charge having a sign opposite that ofthe dissociative group of dye is used to cause ionic mutual interaction (coulombic mutual interaction) and hydrophobic mutual interaction in combination, whereby the dye molecule is fixed.
  • This mutual interaction is a technique known in the art of imaging, particularly photography (especially dye diffusion transferring color photographic material) and is widely used in the art of ink jet recording.
  • most dyes have an anionic dissociative group.
  • cationic compounds are often used on the part of mordant.
  • cationic compounds include compounds having aminic nitrogen atom (e.g., primary amine, secondary amine, tertiary amine, quaternary ammonium salt, nitrogen-containing heterocyclic compound), and metal salt compounds. It is preferred that the mordant be contained in the coloring material-receiving layer.
  • inorganic mordants include polyvalent water-soluble metal salts and hydrophobic metal salt compounds.
  • the inorganic mordants include salts or complexes of metal selected from the group consisting of magnesium, aluminum, calcium, scandium, titanium, vanadium, manganese, iron, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zircomum, molybdenum, indium, barium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, hafnium, tungsten and bismuth.
  • metal selected from the group consisting of magnesium, aluminum, calcium, scandium, titanium, vanadium, manganese, iron, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zircomum, molybdenum, indium, barium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gad
  • these metal salts or complexes include calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, cupric chloride, cupric ammonium chloride (II) dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate hexahydrate, nickel amide sulfate tetrahydrate, aluminum sulfate, aluminum alum, basic polyaluminum hydroxide, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate,
  • the inorganic mordants employable herein include aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, and compounds (salts or complexes) of metal belonging to the group IITB ofthe periodic table.
  • the amount ofthe aforementioned mordant to be contained in the coloring material- receiving layer is preferably from 0.01 g/m 2 to 5 g/m 2 , more preferably from 0.1 g/m 2 to 3 g/m 2 .
  • the aforementioned hydrogen-bonding group in the case where the aforementioned hydrogen-bonding group is connected to the dye, it can be introduced as a water-soluble moiety ofthe dye molecule, can be introduced via a connecting group or can be separately introduced as a part ofthe molecule.
  • the amount ofthe dye ofthe invention to be used is preferably from 20 to 100% by weight, more preferably from 30 to 100% by weight based on the total weight ofthe dyes to be incorporated in the ink.
  • the image-receiving material preferably comprises a compound having a structure having a hydrogen-bonding group that induces hydrogen bond.
  • This compound may be separately added in the form of a special compound or may be previously contained in other materials (either low molecular compound or polymer) which are then incorporated in the image-receiving material.
  • this compound is introduced in other polymer materials. It is particularly preferred that such a substituent be introduced in the structure ofthe mordant.
  • the content ofthe polymer, if contained in the mordant is from 0.01 to 90%, preferably from 0.1 to
  • the effect ofthe invention is exerted between the dye substituted stereospecifically by a plurality of hydrogen-bonding dissociative groups and the image-receiving material comprising a dye-fixing material having a dye-accepting structure in its molecule. It is further preferred that an image-receiving material comprising an organic amine-based mordant as a mordant be used. Specific examples of these organic amine-based mordants will be given below, but the invention is not limited thereto.
  • the dyes to be used in the invention including those represented by the general formulae (1-1) to (1-4), will be described hereinafter.
  • a dye having an oxidation potential of more positive than 1.0 V (more preferably more positive than 1.1 V, particularly more positive than 1.15 V) is preferably used.
  • the use of a dye having an oxidation potential of more positive than 1.0 V makes it possible to obtain an image excellent in durability, particularly ozone resistance.
  • the oxidation potential (Eox) can be easily measured by those skilled in the art. For the details ofthe method for measuring the oxidation potential, reference can be made to P. Delahay, "New Instrumental Methods in Electrochemistry", 1954, Interscience Publishers, A. J.
  • the measurement of oxidation potential is carried out by dissolving the test specimen in a solvent such as dimethylformamide and acetonitrile containing a supporting electrolyte such as sodium perchlorate and tetrapropylammonium perchlorate in a concentration of from 1 x 10 2 to 1 x 10 s mol/1, and then measuring the test solution for oxidation potential with respect to SCE (saturated calomel electrode) using cyclic voltammetry.
  • SCE saturated calomel electrode
  • This value may deviate by scores of millivolts due to the effect of difference in potential between solutions or resistivity of test solution.
  • a standard specimen e.g., hydroquinone
  • the potential (vs SCE) measured in dimethylformamide containing 0.1 mol dm "3 of tetrapropylammonium perchlorate as a supporting electrolyte is defined as oxidation potential of dye.
  • concentration of dye 0.001 mol dm "3
  • oxidation potential of dye There are some cases where a water-soluble dye can be difficultly dissolved directly in N,N-dimethyl formamide. In this case, water is used in an amount as small as possible to dissolve the dye. The dye solution is diluted with N,N-dimethylformamide so that the water content is 2% or less, and then measured.
  • the value of oxidation potential Eox indicates the transferability of electrons from the specimen to the electrode.
  • the incorporation of electron-withdrawing group causes the oxidation potential to be more positive while the incorporation of electron-donative group causes the oxidation potential to be more negative.
  • dyes having the aforementioned properties include azo dyes (yellow dye, magenta dye, black dye) and phthalocyanine dyes (cyan dye) having specific properties and structures. These dyes will be described hereinafter.
  • the yellow dye to be used in the invention preferably has an oxidation potential of more positive than 1.0 V (vs SCE), more preferably more positive than 1.1 V (vs SCE), particularly more positive than 1.15 V (vs SCE) from the standpoint of fastness, particularly to ozone gas.
  • an azo dye satisfying the aforementioned requirements is particularly preferred.
  • a n and B n each independently represent a heterocyclic group which may be substituted.
  • the heterocyclic group is preferably a heterocyclic group formed by a 5-membered or 6- membered ring.
  • the heterocyclic group may have a monocyclic structure or a polycyclic structure formed by the condensation of two or more rings or may be an aromatic heterocyclic group or non-aromatic heterocyclic group.
  • hetero atoms constituting the aforementioned heterocyclic group there are preferably used nitrogen, oxygen and sulfur atoms.
  • the suffix n represents an integer 1 or 2, preferably 2.
  • L represents a substituent bonded to A n or Bn at arbitrary position, with the proviso that when n is 1, L represents a hydrogen atom or monovalent substituent and when n is 2, L represents a mere bond or divalent connecting group.
  • Preferred examples ofthe heterocyclic group represented by An in the general formula (1-1) include 5- pyrazolone, pyrazole, triazole, oxazolone, isooxazolone, barbituric acid, pyridone, pyridine, rhodanine, pyrazolinedione, pyrazolopyridone, Meldrum's acid, and condensed heterocyclic group having an aromatic hydrocarbon ring or heterocyclic group condensed to these heterocyclic groups.
  • Preferred among these heterocyclic groups are 5-pyrazolone, 5-aminopyrazole, pyridone, 2,6-diaminopyridine, and pyrazoloazoles.
  • heterocyclic groups are 5-aminopyrazole, 2-hydroxy-6-pyridone, 2,6- diaminopyridine, and pyrazoloazoles.
  • heterocyclic group represented by Bn include pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, cinnoline, phthaladine, quinoxaline, pyrrole, indole, furane, benzofurane, thiophene, benzothiophene, pyrazole, imidazole, benzoimidazole, triazole, oxazole, isoxazole, benzoxazole, thiazole, benzothiazole, benzothiazole, isothiazole, benzoisothiazole, thiadiazole, benzoisoxazole, pyrrolidine, piperidine, piperazine, imidazolidine, and
  • heterocyclic groups Preferred among these heterocyclic groups are pyridine, quinoline, thiophene, pyrazole, imidazole, benzoimidazole, triazole, oxazole, isoxazole, benzoxazole, thiazole, benzothiazole, isothiazole, benzoisothiazole, thiadiazole, and benzoisoxazole. More desirable among these heterocyclic groups are quinoline, thiophene, pyrazole, benzoxazole, benzoisoxazole, isothiazole, imidazole, benzothiazole, and thiadiazole.
  • heterocyclic groups are pyrazole, benzoxazole, benzoxazole, imidazole, 1,2,4-thiadiazole, and 1,3,4-thiadiazole.
  • substituents on A and B ⁇ include halogen atoms, alkyl groups, cycloalkyl groups, aralkyl groups, alkenyl groups, alkinyl groups, aryl groups, heterocyclic groups, cyano groups, hydroxyl groups, nitro groups, alkoxy groups, aryloxy groups, silyloxy groups, heterocyclic oxy groups, acyloxy groups, carbamoyloxy groups, alkoxycarbonyloxy groups, aryloxycarbonyloxy groups, amino groups, acylamino groups, aminocarbonylamino groups, alkoxycarbonylamino groups, aryloxycarbonylamino groups, sulfamoylamino groups, alkylsulfonylamino groups, arylsulfon
  • Examples ofthe monovalent substituent represented by L include the aforementioned substituents on A and B , and the following ionic hydrophilic groups.
  • Examples ofthe divalent connecting group represented by L include alkylene group, arylene group, heterocyclic residue, -CO-, -SO n - (in which n is 0, 1 or 2), -NR- (in which R represents a hydrogen atom, alkyl group or aryl group), -0-, and divalent group comprising these groups in combination.
  • the ionic hydrophilic group include sulfo groups, carboxyl groups, phosphono groups, and quaternary ammonium groups.
  • Preferred among these ionic hydrophilic groups are carboxyl groups, phosphono groups, and sulfo groups. Particularly preferred among these ionic hydrophilic groups are carboxyl groups and sulfo groups.
  • the carboxyl groups, phosphono groups and sulfo groups may be in the form of salt.
  • the counter ion forming the salt include ammonium ion, alkaline metal ion (e.g., lithium ion, sodium ion, potassium ion), and organic cation (e.g., tetramethylammonium ion, tetramethylguanidium ion, tetramethylphosphomum ion).
  • Preferred among these counter ions are alkaline metal salts.
  • Ri and R 3 each represent a hydrogen atom, cyano group, alkyl group, cycloalkyl group, aralkyl group, alkoxy group, alkylthio group, arylthio group, aryl group or ionic hydrophilic group;
  • R 2 represents a hydrogen atom, alkyl group, cycloalkyl group, aralkyl group, carbamoyl group, acyl group, aryl group or heterocyclic group; and
  • R 4 represents a heterocyclic group, general formula (1-B)
  • R 5 represents a hydrogen atom, cyano group, alkyl group, cycloalkyl group, aralkyl group, alkoxy group, alkylthio group, arylthio group, aryl group or ionic hydrophilic group;
  • Re represents a heterocyclic group, general formula (1-C)
  • R 7 and R 9 each independently represent a hydrogen atom, cyano group, alkyl group, cycloalkyl group, aralkyl group, aryl group, alkylthio group, arylthio group, alkoxycarbonyl group, carbamoyl group or ionic hydrophilic group;
  • Rs represents a hydrogen atom, halogen atom, alkyl group, alkoxy group, aryl group, aryloxy group, cyano group, acylamino group, sulfonylamino group, alkoxycarbonylamino group, ureido group, alkylthio group, arylthio group, alkoxycarbonyl group, carbamoyl group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, acyl group, amino group, hydroxy group or ionic hydrophilic group; and R w represents a heterocyclic group.
  • the alkyl groups represented by Ri, R 2 , R 3 , R5, R7, Rs and R 9 contain a substituted or unsubstituted alkyl group. These alkyl groups each preferably have from 1 to 20 carbon atoms. Examples ofthe aforementioned substituents include hydroxyl groups, alkoxy groups, cyano groups, halogen atoms, and ionic hydrophilic groups.
  • alkyl groups examples include methyl, ethyl, butyl, isopropyl, t-butyl, hydroxyethyl, methoxyethyl, cyanoethyl, trifiuoromethyl, 3-sulfopropyl, and 4-sulfobutyl.
  • the cycloalkyl groups represented by Ri, R 2 , R3, R5, R?, Rs and R9 include a substituted or unsubstituted cycloalkyl group. These cycloalkyl groups each preferably have from 5 to 12 carbon atoms. Examples ofthe substituents on the cycloalkyl group include ionic hydrophilic groups.
  • Examples ofthe cycloalkyl group include cyclohexyl groups.
  • Examples ofthe aralkyl groups represented by Ri, R 2 , R 3 , R 5 , R 7 , Rs and R 9 include substituted and unsubstituted aralkyl groups. These aralkyl groups each preferably have from 7 to 20 carbon atoms. Examples ofthe substituents on the aralkyl group include ionic hydrophilic groups. Examples ofthe aralkyl group include benzyl, and 2-phenethyl. Examples ofthe aryl groups represented by Ri, R 2 , R 3 , R5, R7, Rs and R 9 include substituted and unsubstituted aryl groups.
  • aryl groups each preferably have from 6 to 20 carbon atoms.
  • substituents on the aryl group include alkyl groups, alkoxy groups, halogen atoms, alkylamino groups, and ionic hydrophilic groups.
  • the aryl group include phenyl, p-tollyl, p-methoxyphenyl, o-chlorophenyl, and m-(3 -sulfopropylamino)phenyl.
  • alkylthio groups represented by Ri, R 2 , R 3 , R5, R7, Rs and Rg include substituted and unsubstituted alkylthio groups.
  • alkylthio groups each preferably have from 1 to 20 carbon atoms.
  • substituents on the alkylthio group include ionic hydrophilic groups.
  • the alkylthio group include methylthio, and ethylthio group.
  • the arylthio groups represented by Ri, R 2 , R 3 , R5, R 7 , Rs and R 9 include substituted and unsubstituted arylthio groups.
  • These arylthio groups each preferably have from 6 to 20 carbon atoms.
  • substituents on the arylthio group include alkyl groups, and ionic hydrophilic groups.
  • the arylthio group examples include phenylthio, and p-tolylthio group.
  • the heterocyclic group represented by R 2 preferably is a 5- or 6-membered heterocyclic group which may be further condensed. Preferred examples ofthe hetero atoms constituting the heterocyclic group include nitrogen, sulfur and oxygen atoms.
  • the heterocyclic groups may be aromatic or non-aromatic. These heterocyclic groups may be further substituted. Examples ofthe substituents on the heterocyclic group include those listed with reference to the aryl group described later. Preferred examples ofthe heterocyclic groups include a 6-membered nitrogen-containing aromatic heterocyclic group.
  • Such a 6-membered nitrogen-containing aromatic heterocyclic group include triazine, pyrimidine, and phthaladine.
  • the halogen atom represented by Rg include fluorine atom, chlorine atom, and bromine atom.
  • the alkoxy groups represented by R R 3 , R 5 and Rg include substituted and unsubstituted alkoxy groups. These alkoxy groups each preferably have from 1 to 20 alkoxy groups.
  • Examples ofthe substituents include hydroxyl groups, and ionic hydrophilic groups.
  • Examples of the alkoxy groups include methoxy, ethoxy, isopropoxy, methoxye ⁇ ioxy, ydroxyethoxy, and 3-carboxypropoxy.
  • Examples ofthe aryloxy group represented by Rg include substituted and unsubstituted aryloxy groups. These aryloxy groups each preferably have from 6 to 20 carbon atoms. Examples ofthe substituents on the aryloxy group include alkoxy groups, and ionic hydrophilic groups. Examples ofthe aryloxy groups include phenoxy, p-mefhoxyphenoxy, and o-methoxyphenoxy. Examples ofthe acylamino group represented by Rg include substituted and unsubstituted acylamino groups. These acylamino groups each preferably have from 2 to 20 carbon atoms. Examples ofthe substituents on the acylamino group include ionic hydrophilic groups.
  • Examples ofthe acylamino group include acetarmde, propionamide, benzamide, and 3,5-disulfobenzamide.
  • Examples ofthe sulfonylamino group represented by Rs include alkylsulfonylamino group, arylsulfonyl group, and heterocyclic sulfonylamino group.
  • the alkyl moiety, aryl moiety and heterocyclic moiety of these sulfonylamino groups may have substituents. Examples ofthe aforementioned substituents include those exemplified with reference to the aryl group.
  • These sulfonylamino groups each preferably have from 1 to 20 carbon atoms.
  • Examples ofthe sulfonylamino group include methylsulfonylamino, and etliylsulfonylamino.
  • Examples ofthe alkoxycarbonylamino group represented by Rs include substituted and unsubstituted alkoxycarbonylamino groups. These alkoxycarbonylamino groups each preferably have from 2 to 20 carbon atoms. Examples ofthe substituents on the alkoxycarbonylamino group include ionic hydrophilic groups. Examples ofthe alkoxycarbonylamino group include ethoxycarbonylamino. Examples ofthe ureido group represented by Rs include substituted and unsubstituted ureido groups.
  • ureido groups each preferably have from 1 to 20 carbon atoms.
  • substituents on the ureido group include alkyl groups, and aryl groups.
  • the ureido group include 3-methylureido group, 3,3-dimethylureido group, and 3-phenylureido group.
  • alkoxycarbonyl groups represented by R 7 , Rg and R 9 include substituted and unsubstituted alkoxycarbonyl groups. These alkoxycarbonyl groups each preferably have from 2 to 20 carbon atoms. Examples o the substituents on the alkoxycarbonyl group include ionic hydrophilic groups.
  • Examples of the alkoxycarbonyl group include methoxycarbonyl, and ethoxycarbonyl.
  • the carbamoyl groups represented by R 2 , R7, Rs and Rg include substituted and unsubstituted carbamoyl groups.
  • Examples ofthe substituents on the carbamoyl group include alkyl groups.
  • Examples ofthe carbamoyl group include methylcarbamoyl group, and dimethylcarbamoyl group.
  • Examples ofthe sulfamoyl group represented by Rg include substituted and unsubstituted sulfamoyl groups.
  • Examples ofthe substituents on the sulfamoyl group include alkyl groups.
  • Examples ofthe sulfamoyl group include dimetliylsulfamoyl group, and di ⁇ (2-hydroxyethyl)sulfamoyl group.
  • Examples ofthe alkylsulfonyl group represented by Rg include alkylsulfonyl group, arylsulfonyl group and heterocyclic sulfonyl group which may further have substituents. Examples of these substituents include ionic hydrophilic groups. Examples of these sulfonyl groups include methylsulfonyl, and phenylsulfonyl.
  • Examples ofthe acyl groups represented by R 2 and Rg include substituted and unsubstituted acyl . groups.
  • acyl groups each preferably have from 1 to 20 carbon atoms.
  • substituents on the acyl group include ionic hydrophilic groups.
  • examples ofthe acyl group include acetyl, and benzoyl.
  • Examples ofthe amino group represented by Rg include substituted and unsubstituted amino groups.
  • Examples of the substituents on the amino group include alkyl groups, aryl groups, and heterocyclic groups.
  • Examples ofthe amino group include methylamino, diethylamino, anilino, and 2-chloroanilino.
  • the heterocyclic groups represented by R 4 , Re and R ⁇ 0 are the same as the heterocyclic groups represented by B ⁇ in the general formula (1-1) which may be substituted. • Preferred examples ofthe heterocyclic groups include those listed with reference to Bn in the general formula (1-1). Even more desirable examples ofthe heterocyclic groups include those listed with reference to Bn in the general formula (1-1). Particularly preferred examples ofthe heterocyclic groups include those listed with reference to B n in the general formula (1-1).
  • substituents on the heterocyclic group include ionic hydrophilic groups, C 1 -C 12 alkyl, aryl and arylthio groups, halogen atoms, cyano groups, sulfamoyl groups, sulfonamide groups, carbamoyl groups, and acylamino groups. These alkyl and aryl groups may further contain substituents.
  • R n represents a hydrogen atom or non-metallic substituent
  • Preferred examples ofthe non-metallic substituent represented by R include cyano groups, cycloalkyl groups, aralkyl groups, aryl groups, alkylthio groups, arylthio groups, and ionic hydrophilic groups. These substituents each have the same meamng as those represented by Ri .
  • Preferred examples of these substituents include those listed with reference to Rj. Examples ofthe skeleton ofthe heterocyclic group composed of two 5-membered rings contained in the general formula (1-B) will be given below.
  • substituents on the aforementioned substituents which may further have substituents include substituents which may substitute the heterocyclic groups A and B n in the general formula (1-1).
  • Preferred among the dyes ofthe general formulae (1-A), (1-B) and (1-C) are those represented by the general formula (1-A).
  • Particularly preferred among the dyes ofthe general formula (1-A) is one represented by the following general formula (1-A1).
  • R 21 and R 23 each represent a hydrogen atom, alkyl group, cycloalkyl group, alkoxy group or aryl group;
  • R 22 represents an aryl group or heterocyclic group; and one of X and Y represents a nitrogen atom and the other represents -CR 24 in which R 24 represents a hydrogen or halogen atom or a cyano, alkyl, alkylthio, alkylsulfonyl, alkylsulfinyl, alkyloxycarbonyl, carbamoyl, alkoxy, aryl, arylthio, arylsulfonyl, arylsulfinyl, aryloxy or acylamino group.
  • substituents are hydrogen atom, alkyl group, arylthio group, and aryl group. Particularly preferred among these substituents are hydrogen atom, alkylthio group, and aryl group. These substituents each may be further substituted.
  • Preferred examples ofthe dye to be used in the invention include those disclosed in Japanese Patent Application No. 2003-286844, Japanese Patent Application No. 2002-211683, Japanese Patent Application No. 2002-124832, JP-A-2003-128953, and JP-A-2003-41160. Preferred among these dyes are those exemplified below. The dyes employable herein are not limited to these examples. These compounds can be synthesized according to JP-A-2-24191 and JP-A-2001-279145.
  • the content ofthe yellow dye represented by the general formula (1-1) in the ink is preferably from 0.2 to 20% by weight, more preferably from 0.5 to 15% by weight.
  • the phthalocyanine dye which is a cyan dye will be further described hereinafter.
  • the phthalocyanine dye to be used in the invention preferably is excellent in both light-resistance and ozone resistance and has little change of hue and surface conditions (little bronzing and dye precipitation).
  • the ink show a light-resistance of not smaller than 90% as calculated in terms of percent dye remaining in 3 days when exposed to light from a Xenon lamp at Xe: 1.1 W/m (intermittent) through a TAC filter to a site on a PM photographic image-receiving paper produced by EPSON CO., LTD (reflection density after irradiation/initial concentration x 100) where the reflection density OD is 1.0. It is also desired that the ink show a percent dye remaining of not smaller than 85% in 14 days.
  • the measure of change of hue and surface conditions is the amount of Cu ions present as phthalate after the decomposition of phthalocyanine dye.
  • the amount of Cu compounds present on the actual print is preferably predetermined to be 10 mg/m 2 or less as calculated in terms of Cu ion.
  • the amount of Cu ions to be eluted from the print is preferably 20% or less. All Cu compounds are trapped by the image-receiving material before fading.
  • a phthalocyanine dye having the aforesaid physical properties is obtained by 1) raising the oxidation potential, 2) enhancing the associatiability, 3) introducing an association-accelerating group or strengtliening hydrogen bond during ⁇ - ⁇ stacking, 4) avoiding the introduction of substituents in ⁇ -position, i.e., facilitating stacking, or by other methods.
  • the structural characteristic ofthe phthalocyanine dye to be used in the ink composition is that a phthalocyanine dye the number and position of substituents on which can be predetermined is used while the phthalocyanine dye which has been used in the related art inks is a mixture the number and position of substituents on which cannot be predetermined because it is derived by sulfonation of unsubstituted phthalocyanine.
  • a first structural characteristic is that the phthalocyanine dye ofthe present invention is a phthalocyanine dye obtained without sulfonation of unsubstituted phthalocyanine.
  • a second structural characteristic is introduction of electron-withdrawing group into ⁇ -position of benzene rings of phthalocyanine, particularly into all benzene rings.
  • those substituted on sulfonyl group JP-A-2002-249677, JP- A-2003-119415
  • those substituted on all sulfamoyl groups JP-A-2002-302623, JP-A-2003-3109
  • those substituted on heterocyclic sulfamoyl group JP-A-2002-294097, JP-A-2003-3086
  • those substituted on heterocyclic sulfonyl group JP-A-2002-275386, JP-A-2003-3099
  • those substituted on specific sulfamoyl group JP-A-2002-256167
  • those substituted on carbonyl group 3P-A-2003-213153
  • those having specific substituents for enhancing solubility and ink stability and preventing bronzing are preferred, and in more
  • a first physical characteristic of he phthalocyanine dye ofthe present invention is that it has a high oxidation potential (more positive than 1.0 V).
  • a second physical characteristic ofthe phthalocyanine dye ofthe present invention is that the phthalocyanine dye ofthe present invention has a strong associatiability.
  • Specific examples of such a phthalocyanine dye include those having a specified associatiability of oil-soluble dye (JP-A-2001-342373), and those having a specified associatiability of water-soluble dye (JP-A-2002- 309118).
  • the introduction of associatiable groups makes it more likely that the drop of absorbance can occur and ⁇ max can appear in shorter wavelength range even in a dilute solution.
  • the number and properties (reflection density OD on PM920 image-receiving paper produced by EPSON CO., LTD.) of associatiable groups the more the number of associatiable groups is, the lower is the reflection density OD at the same ion intensity. In other words, it is thought that association proceeds on the image-receiving paper.
  • ozone resistance ozone resistance, light-resistance
  • a dye having many associatiable groups tends to have improved light-resistance as well.
  • the benzene rings of phthalocyanine be provided with substituents. Since there is a trade-off relation between reflection density OD and fastness, it is necessary that light-resistance be raised without weakening associatiability.
  • Preferred embodiments of the cyan ink ofthe present invention comprising a phthalocyanine dye having the aforesaid characteristics are as follows.
  • Cyan ink having a percent dye remaining of 60% or more (preferably 80% o ⁇ more) as measured after 24 hours of storage in 5 ppm atmosphere at the site where printing has been made such that the reflection density is from 0.9 to 1.1 as measured through a status A filter.
  • Cyan ink which can penetrate a specific image-receiving paper to a depth of up to 30% of the upper portion of image-receiving layer.
  • a dye having the aforementioned characteristics there may be used a phthalocyanine dye represented by the aforesaid general formula (1-2).
  • a phtlialocyanine dye has been known as a fast dye but is known to have a poor fastness to ozone gas when used as an ink jet recording dyestuff.
  • an electrophilic group be introduced into the phthalocyanine skeleton to make the oxidation potential more positive than 1.0 V (vs SCE) as previously mentioned.
  • a substituent having a great Hammett's substituent constant ⁇ p (a measure of the electiophilicity or electron-donating properties of substituents) such as sulfinyl group, sulfonyl group and sulfamoyl group makes it possible to make the oxidation potential more positive.
  • a phthalocyanine dye represented by the aforesaid general formula ( 1 -2) is preferably used.
  • the phthalocyanine dye represented by the aforementioned general formula (1-2) will be further described hereinafter.
  • X 22 , X 23 and X 24 each independently represent -SO-Z 2 , -SO2-Z2, - SO 2 NR2 1 R22, sulfo group, -CONR21R22 or -CO2R21.
  • Preferred among these substituents are -SO-Z 2 , -S0 2 -Z 2 , - S0 2 NR 2 ⁇ R 2 2, and -CONR21R22, particularly -SO 2 -Z2 and -S0 2 NR 2 ⁇ R22 5 most preferably -S0 2 -Z 2 .
  • any one of a 2 ⁇ to a 2 represents an integer of 2 or more
  • to X 24 may be the same or different and each independently represent any ofthe aforesaid groups.
  • X 2 ⁇ , X 22 , X 23 and X 24 may be the same substituent or may all be the same but partially different substituents such as -SO 2 -Z 2 in which Z 2 is different among X 2 ⁇ to X 24 or maybe different substituents, e.g., -S0 2 -Z 2 and -SO2NR 2 1R2 2 .
  • the aforesaid groups Z 2 each independently represent substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted aralkyl group, substituted or unsubstituted aryl group and substituted or unsubstituted heterocyclic group.
  • R 2 ⁇ and R 22 each independently represent a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted aralkyl group, substituted or unsubstituted aryl group or substituted or unsubstituted heterocyclic group.
  • R21 and R 22 are a hydrogen atom at the same time.
  • the substituted or unsubstituted alkyl group represented by R 2 ⁇ , R 22 or Z 2 is preferably a C 1 -C 3 0 alkyl group.
  • the alkyl group is preferably branched, and it is particularly preferred that the alkyl group have asymmetric carbons (used in racemate form).
  • the substituents on the alkyl group include those listed with reference to the case where Z ⁇ , R 21 , R 2 2, Y21, Y 22 , Y 23 and Y 24 are able to have further substituents as described later.
  • Particularly preferred among these substituents are hydroxyl group, ether group, ester group, cyano group, amide group and sulfonamide group because they enhance the association of dyes and hence the fastness thereof.
  • the alkyl group may have a halogen atom or ionic hydrophilic group.
  • the number of carbon atoms in the alkyl group does not include that of carbon atoms in the substituents. This can apply to other groups.
  • the substituted or unsubstituted cycloalkyl group represented by R 2 ⁇ , R 22 or Z 2 is preferably a C5-C30 cycloalkyl group. Particularly from the reason of enhancement of dye solubility or ink stability, it is particularly preferred that the cycloalkyl group have asymmetric carbons (used in racemate form). Examples of the substituents on the cycloalkyl group include those listed with reference to the case where Z 2 , R21, R22, Y21, Y 22 , Y 23 and Y 24 are able to have further substituents as described later.
  • substituents are hydroxyl group, ether group, ester group, cyano group, amide group and sulfonamide group because they enhance the association of dyes and hence the fastness thereof.
  • the cycloalkyl group may have a halogen atom or ionic hydrophilic group.
  • the substituted or unsubstituted alkenyl group represented by R 21 , R 22 or Z 2 is preferably a C2-C30 alkenyl group.
  • the alkenyl group is preferably branched. It is particularly preferred that the alkenyl group have asymmetric carbons (used in racemate form).
  • Examples ofthe substituents on the alkenyl group include those listed with reference to the case where Z 2 , R2 1 , . 2 , Y 2 1.
  • Y 22 , Y 23 and Y 24 are able to have further substituents as described later.
  • Particularly preferred among these substituents are hydroxyl group, ether group, ester group, cyano group, amide group and sulfonamide group because they enhance the association of dyes and hence the fastness thereof.
  • the alkenyl group may have a halogen atom or ionic hydrophilic group.
  • the substituted or unsubstituted aralkyl group represented by R 2 ⁇ , R 22 or Z 2 is preferably a C7-C30 aralkyl group.
  • the aralkyl group is preferably branched. It is particularly preferred that the aralkyl group have asymmetric carbons (used in racemate form).
  • substituents on the aralkyl group include those listed with reference to the case where Z 2 , R21, R22, Y21, Y22, Y23 and Y 24 are able to have further substituents as described later. Particularly preferred among these substituents are hydroxyl group, ether group, ester group, cyano group, amide group and sulfonamide group because they enhance the association of dyes and hence the fastness thereof.
  • the aralkyl group may have a halogen atom or ionic hydrophilic group.
  • the substituted or unsubstituted aryl group represented by R 2 ⁇ , R 22 or Z is preferably a C6-C30 aryl group.
  • the substituents on the aryl group include those listed with reference to the case where Z 2 , R 21 , R 22 , Y 2 ⁇ , Y 22 , Y 23 and Y 24 are able to have further substituents as described later.
  • en electron- withdrawing group is preferred because it causes the oxidation potential ofthe dye to be higher and thus enhances the fastness thereof.
  • Examples ofthe electron-withdrawing group include those having a positive Hammett's substituent constant ⁇ p.
  • Preferred examples ofthe electron-withdrawing group include halogen atom, heterocyclic group, cyano group, carboxyl group, acylamino group, sulfonamide group, sulfamoyl group, carbamoyl group, sulfonyl group, imide group, acyl group, sulfo group, and quaternary ammonium group.
  • the electron-withdrawing groups are cyano group, carboxyl group, sulfamoyl group, carbamoyl group, sulfonyl group, imide group, acyl group, sulfo group, and quaternary ammonium group.
  • the heterocyclic group represented by R 2 ⁇ , R 22 or Z 2 is preferably a 5- or 6-membered heterocyclic group which may be further condensed.
  • the heterocyclic group may be an aromatic heterocyclic group or non- aromatic heterocyclic group.
  • heterocyclic group represented by R 2 ⁇ , R 22 or Z will be exemplified in the form of heterocyclic ring with its substitution position omitted, but the substitution position is not limited and, for example, pyridine may have substituents on the 2-, 3- or 4-position.
  • heterocyclic ring examples include pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, cinnoline, phthaladine, quinoxaline, pyrrole, indole, furane, benzofurane, thiophene, benzothiophene, pyrazole, imidazole, benzimidazole, triazole, oxazole, benzoxaole, thiazole, benzothiazole, isothiazole, benzisothiazole, thiadiazole, isooxazole, benzisooxazole, pyrrolidine, piperidine, piperazine, imidazolidine, and thiazoline.
  • aromatic heterocyclic groups are preferred.
  • Preferred examples ofthe aromatic heterocyclic groups include pyridine, pyrazine, pyrimidine, pyridazine, triazine, pyrazole, imidazole, benzimidazole, triazole, thiazole, benzothiazole, isothiazole, benzisothiazole, and thiadiazole.
  • These aromatic heterocyclic groups may have substituents, and examples ofthe substituents on the aromatic heterocyclic group include those listed with reference to the case where Z 2 , R_ ⁇ , R2 2 , Y2 1 , Y2 2 , Y23 and Y 24 are able to have further substituents as described later.
  • Y 21 , Y. 2 , Y23 and Y 24 each independently represent a hydrogen atom, halogen atom, alkyl group, cycloalkyl group, alkenyl group, aralkyl group, aryl group, heterocyclic group, cyano group, hydroxyl group, nitro group, amino group, alkylamino group, alkoxy group, aryloxy group, acylamino group, arylamino group, ureido group, sulfamoyl group, alkylthio group, arylthio group, alkoxycarbonylamino group, sulfonamide group, carbamoyl group, sulfamoyl group, sulfonyl group, alkoxycarbonyl group, heterocyclic oxy group
  • Preferred among these groups are hydrogen atom, halogen atom, alkyl group, aryl group, cyano group, alkoxy group, amide group, ureido group, sulfonamide group, carbamoyl group, sulfamoyl group, alkoxycarbonyl group, carboxyl group and sulfo group, particularly hydrogen atom, halogen atom, cyano group, carboxyl group and sulfo group, most preferably hydrogen atom.
  • Z 2 , R 2 ⁇ , R 22 , Y 2 ⁇ , Y 22 , Y 23 and Y 24 may further have substituents, they may further have the following substituents.
  • Examples ofthe substituents on Z 2 , R 2 ⁇ , R 22 , Y 2 ⁇ , Y 22 , Y23 and Y 24 include C 1 - 2 straight-chain or branched alkyl group, C 7 -C ⁇ 8 straight-chain or branched aralkyl group, C 2 -C 12 straight-chain or branched alkenyl group, C 2 -C ⁇ 2 straight-chain or branched alkinyl group, C3-C 12 straight-chain or branched cycloalkyl group, C 3 - C 12 straight-chain or branched cycloalkenyl group (These groups each preferably have branches for the reason of dye solubility or ink stability. It is particularly preferred that these groups have asymmetric carbons.
  • these groups include methyl group, ethyl group, propyl group, isopropyl group, sec-butyl group, t- butyl group, 2-ethylhexyl group, 2-methylsulfonylethyl group, 3-phenoxypropyl group, trifluoromethyl group, and cyclopentyl group), halogen atom (e.g., chlorine atom, bromine atom), aryl group (e.g., phenyl group, 4-t- butylphenyl group, 2,4-di-t-amylphenyl group), heterocyclic group (e.g., i idazolyl group, pyrazolyl group, triazolyl group, 2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group), cyano group, hydroxyl group, nitro group, carboxy group, amino group, alkyloxy group (e.g., methoxy group,
  • the ionic hydrophilic group include sulfo group, carboxyl group, phosphono group, and quaternary ammonium group. Preferred among these ionic hydrophilic groups are carboxyl group, phosphono group, and sulfo group, and particularly preferred among these ionic hydrophilic groups are carboxyl group and sulfo group.
  • the carboxyl group, phosphono group and sulfo group may be used in the form of salt, and examples of the counter ion forming the salt include ammonium ion, alkaline metal ion (e.g., lithium ion, sodium ion, potassium ion), and organic cation (e.g., tetramethylammonium ion, tetramethylguanidium ion, tetramethylphosphonium ion).
  • alkaline metal ion e.g., lithium ion, sodium ion, potassium ion
  • organic cation e.g., tetramethylammonium ion, tetramethylguanidium ion, tetramethylphosphonium ion.
  • Preferred among these counter ions are alkaline metal ions, and particularly preferred among these counter ions is lithium ion because it enhances the dye solubility and hence the ink stability.
  • the number of ionic hydrophilic groups is preferably at least 2 per molecule of phthalocyanine-based dye, and it is particularly preferred that there be contained at least two sulfo groups and/or carboxyl groups in the phthalocyanine-based dye.
  • the suffixes a 2 ⁇ to a 24 and b 2 ⁇ to b 24 represent the number ofthe substituents X 2 ⁇ to X 24 and Y 2 ⁇ to Y 24 , respectively.
  • the suffixes a 2 ⁇ to a 24 each independently represent an integer of from 0 to 4, with the proviso that the suffixes a 2 ⁇ to a 24 are not 0 at the same time.
  • the suffixes b 21 to b 2 each independently represent an integer of from 0 to 4.
  • any of a2i to a 24 and b 2 ⁇ to b 24 is an integer of 2 or more, there are a plurality of any of X 2 ⁇ 's to X 24 's and Y 2 ⁇ 's to Y 2 4's and they may be the same or different.
  • a 2 ⁇ represents 1 or 2 while b 2 ⁇ represents 3 or 2
  • a 2 ⁇ represents 1 while b 2 ⁇ represents 3.
  • the combinations a 22 andb 22 , a 2 3 andb 23 , and a 2 4 andb 24 are similar to the combination of a 2 ⁇ andb 2 ⁇ , and preferred examples of the combinations a 22 and b 22 , a 23 and b 23 , and a 24 and b 24 are also similar to that ofthe combination of a 2 ⁇ and b 2 ⁇ .
  • M represents a hydrogen atom, metal element or oxide, hydroxide or halide thereof.
  • M other than hydrogen atom examples include metal elements such as Li, Na, K, Mg, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Ft, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Si, Ge, Sn, Pb, Sb and Bi.
  • metal oxide examples include VO, and GeO.
  • Preferred examples of metal hydroxide include Si(OH) 2 , Cr(OH 2 , and Sn(OH) .
  • metal halide include A1C1, SiCl 2 , VC1, VC1 2 , VOC1, FeCl, GaCl, and ZrCl.
  • Pc phthalocyanine ring
  • L divalent connecting group
  • M's may be the same or different.
  • the divalent connecting group represented by L include oxy group -0-, thio group -S-, carbonyl group -CO-, sulfonyl group -S0 2 -, imino group -NH-, methylene group -CH 2 -, and group formed by combining these groups.
  • the compound ofthe general formula (1-2) preferably has various substituents at least one of which is one ofthe preferred groups listed above, and more preferably, more ofthe various substituents are the preferred groups listed above, and most preferably, all ofthe various substituents are the preferred groups listed above.
  • Preferred among the phthalocyanine dyes represented by the general formula (1-2) is a phthalocyanine dye having the structure represented by the aforesaid general formula (1-5).
  • the phthalocyanine dye represented by the general formula (1-5) ofthe invention will be described in detail hereinafter.
  • X 5 ⁇ to 54 and Y 51 to Y 58 have the same meaning as X 21 to X 24 and Y 2 ⁇ to Y 24 in the general formula (1-2) and preferred examples of X 51 to X 54 and Y 51 to Y5 8 are the same as those in the general formula (1-2).
  • Mi has the same meamng as M in the general formula (1-2) and preferred examples of Mi are the same as those in the general formula (1-2).
  • a 5 ⁇ to a 54 each independently represent an integer of 1 or 2, and preferably, the sum of si, a5 2 , a 53 and a 54 is equal to or smaller than 4 and equal to or greater than 6, and it is particularly preferred that asi, as 2 , a 53 and as 4 each are 1.
  • X 5 ⁇ , X 52 , X 53 and X 54 may be the same substituent, or X 5 ⁇ , X 52 , X 53 and X5 4 each may be a substituent of the same kind but partially different, e.g., -S0 2 -Z 2 in which Z 2 differs among X5 1 , X S2 , X 53 and X 54 , or X 5 X 52 , X53 and X5 4 may be different substituents, e.g., -S0 2 -Z 2 and -S0 2 NR 2 ⁇ R 22 .
  • Particularly preferred examples ofthe combination of substituents among the phthalocyanine dyes represented by the general formula (1-5) will be given below.
  • X 5J to X 54 each independently represent -SO-Z 2 , -S0 2 -Z 2 , -S0 2 NR 2 ⁇ R 22 or -CONR 2 ⁇ R 22 , particularly -S0 2 -Z 2 or -SO2NR21R22, most preferably -S0 2 -Z 2 .
  • Z 2 S each represent a substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group or substituted or unsubstituted heterocyclic group, and most desirable among these groups are substituted alkyl group, substituted aryl and substituted heterocyclic group.
  • R 21 and 22 each independently represent a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group or substituted or unsubstituted heterocyclic group, particularly a hydrogen atom, substituted alkyl group, substituted aryl group or substituted heterocyclic group.
  • R 2 ⁇ and R 22 each are a hydrogen atom at the same time.
  • the substituents have asymmetric carbons (used in racemate form).
  • the substituents have a hydroxyl group, ether group, ester group, cyano group, amide group or sulfonamide group incorporated therein.
  • Y 5 ⁇ to Y 58 each independently represent a hydrogen atom, halogen atom, alkyl group, aryl group, cyano group, alkoxy group, amide group, ureido group, sulfonamide group, carbamoyl group, sulfamoyl group, alkoxycarbonyl group, carboxyl group or sulfo group, particularly hydrogen atom, halogen atom, cyano group, carboxyl group or sulfo group, most preferably hydrogen atom.
  • the suffixes asi to as 4 each independently represent 1 or 2, and it is particularly preferred that asi to a s4 each be 1 at the same time.
  • Mi represents a hydrogen atom, metal element or oxide, hydroxide or halide thereof, particularly Cu, Ni, Zn or Al, most preferably Cu.
  • the ionic hydrophilic group include sulfo group, carboxyl group, phosphono group, and quaternary ammonium group. Preferred among these ionic hydrophilic groups are carboxyl group, phosphono group, and sulfo group, and particularly preferred among these ionic hydrophilic groups are carboxyl group and sulfo group.
  • the carboxyl group, phosphono group and sulfo group may be used in the form of salt, and examples ofthe counter ion forming the salt include ammonium ion, alkaline metal ion (e.g., lithium ion, sodium ion, potassium ion), and organic cation (e.g., tetrametlrylammomum ion, tetramethyl guanidium ion, tetramethylphosphomum ion).
  • alkaline metal ion e.g., lithium ion, sodium ion, potassium ion
  • organic cation e.g., tetrametlrylammomum ion, tetramethyl guanidium ion, tetramethylphosphomum ion.
  • Preferred among these counter ions are alkaline metal ions, and particularly preferred among these counter ions is lithium ion because it enhances the dye solubility and hence the ink stability
  • the number of ionic hydrophilic groups is preferably at least 2 per molecule of phthalocyanine-based dye, and it is particularly preferred that there be contained at least two sulfo groups and/or carboxyl groups in the phthalocyanine-based dye.
  • the compound ofthe general formula (1-5) preferably has various substituents at least one of which is one ofthe preferred groups listed above, and more preferably, more ofthe various substituents are the preferred groups listed above, and most preferably, all ofthe various substituents are the preferred groups listed above.
  • the phthalocyanine dye represented by the general formula (1-5) it is preferred that at least one electron-withdrawing group such as sulfinyl group, sulfonyl group and sulfamoyl group be incorporated in each of four benzene rings in the phthalocyanine such that ⁇ p value ofthe substituents in the entire phthalocyanine skeleton totals not smaller than 1.6.
  • the Hammett's substituent constant ⁇ p will be described hereinafter.
  • Hammett's rule is an empirical rule which L. P. Hammett proposed in 1935 to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives, and the validity of this empirical rule has been widely accepted today.
  • these substituents are defined or described by Hammett's substituent constant ⁇ p, but this does not mean that the known values found in the aforementioned literatures are not limited to certain substituents and it goes without saying that even if the values are unknown in literatures, they contain substituents which may fall within the defined range when measured according to Hammett's rule. Further, the compounds ofthe present invention contain those which are not benzene derivatives, and as a measure for indicating the electron effect of substituents there is used ⁇ p value regardless of substitution position. In the present invention, ⁇ p value is used in this sense.
  • Y 51 , Y 52 , Y 53 , Y5 4 , Y 55 , Y 5 6, Y5 7 and Y 58 are in 1-, 4-, 5-, 8-, 9-, 12-, 13- and 16-positions, respectively.
  • ⁇ -position substitution type Phthalocyanine dye having a specific substituent on 2- and or 3-position, 6- and/or 7-position, 10- and or 11-position, or 14- and/or 15-position
  • phthalocyanine dye having a specific substituent irregularly on 1- to 16-position Phthalocyanine dye having a specific substituent irregularly on 1- to 16-position
  • the aforementioned ⁇ -position substitution type, opposition substitution type and ⁇ , ⁇ -position mixed substitution type are used.
  • the phthalocyanine derivative to be used in the invention can be synthesized by, e.g., methods described or cited in Shirai and Kobayashi, "Phthalocyanine - Chemistry and Function -", IPC Co., Ltd., pp. 1 to 62, C. C. Leznoff-AB.P.
  • the phthalocyanine compound represented by the general formula (1-2) to be used in the invention can be synthesized by, e.g., sulfonation reaction, sulfonylchloration reaction and amidation reaction of unsubstituted phthalocyanine compound as disclosed in WO00/17275, 00/08103, 00/08101 and 98/41853 and JP-A-10-36471. In this case, since sulfonation can occur on any position ofthe phthalocyanine nucleus, it is difficult to control the sulfonated number of substituents.
  • the phthalocyanine dye when many electron-withdrawing groups such as sulfamoyl group are incorporated in the phthalocyanine nucleus, the phthalocyanine dye is provided with a more positive oxidation potential and hence an enlianced ozone fastness.
  • the reaction mixture contains a phthalocyanine dye having a small number of electron- withdrawing groups incorporated therein, i.e., more negative oxidation potential.
  • a synthesis method capable of inhibiting the production of a compound having a more negative oxidation potential is preferably employed.
  • the phthalocyanine compound represented by the general formula (1-5) ofthe invention can be derived from a tetiasuffophthalocyanine compound obtained by, e.g., reacting a phthalonitrile derivative (compound P) represented by the following general formula and or a dii inoisoindoline derivative (compound Q) represented by the following general formula with a metal derivative represented by the general formula (1-6) or reacting a 4-sulfophthalocyanine derivative (compound R) represented by the following general formula with a metal derivative represented by the general formula (1-6).
  • Xp corresponds to X 5 ⁇ , X 52 , X 53 or X 54 in tiie general formula (1-5).
  • Yq and Yq' each correspond to Y 5 ⁇ , Y 52 , Y53, Y54, Y55, Yse, Y57 or Y 58 in the general formula (1-5).
  • M' represents a cation. Examples ofthe cation represented by M' include alkaline metal ions such as Li, Na and K ions and organic cations such as triethylammomum ion and pyridinium ion.
  • desired substituents can be incorporated by a predetermined number.
  • the aforementioned synthesis method can be used because it is extremely excellent as compared with the aforementioned method for synthesis ofthe phthalocyanine compound ofthe general formula (1-2).
  • the phthalocyanine compound represented by the general formula (1-5) thus obtained is a mixture of compounds represented by the following general formulae (a)-l to (a)-4 which are isomeric with the substitution position on Xp, i.e., ⁇ -position substitution type mixture.
  • any of these substitution types has an oxidation potential of more positive than 1.0 V (vs SCE).
  • vs SCE 1.0 V
  • ⁇ -position substitution type is obviously better than ⁇ , ⁇ -position mixed substitution type in hue, light fastness, ozone fastness, etc.
  • Specific examples ofthe phthalocyanine dyes represented by the general formula (1-2) or (1-5) exemplary compounds I-l to 1-12 and exemplary compounds 101 to 190
  • the phthalocyanine dye to be used in the present invention is not limited thereto.
  • the structure ofthe phthalocyanine compound represented by M-Pc(Xp ⁇ )m(Xp 2 )n in Compound Nos.46 to 190 is as follows.
  • the phthalocyanine dye represented by the general formula (1-2) can be synthesized according to the patent cited above.
  • the phthalocyanine dye represented by the general formula (1-5) can be synthesized by the aforementioned method as well as the method disclosed in JP-A-2001-226275, JP-A-2001-96610, JP-A-2001- 47013 and JP-A-2001-193638.
  • the starting material, intermediate dye and synthesis route are not limited to those according to these methods.
  • the content ofthe phthalocyanine dye represented by the general formula (1-2) in the ink is preferably from 0.2 to 20% by weight, more preferably from 0.5 to 15% by weight.
  • the azo dye to be used in the invention is preferably a dye having a maximal absorption at a wavelength of from 500 nm to 580 nm in an aqueous medium and an oxidation potential of more positive than 1.0 V (vs SCE).
  • the heterocyclic ring A and the heterocyclic ring B in the aforementioned general formula may have the same structure.
  • the heterocyclic ring A and heterocyclic ring B each are in detail a 5- or 6-membered heterocyclic ring which is selected from pyrazole, imidazole, triazole, oxazole, thiazole, selenazole, pyridone, pyrazine, pyrimidine and pyridine. In some detail, they are described in JP-A-2001-279145, JP-A-2001-15614, JP-A-2002-309116, JP-A-2003- 12650, etc.
  • the second preferred structural characteristic ofthe aforesaid azo dye is that the azo group is an azo dye having an aromatic nitrogen-containing 6-membered heterocyclic ring directly connected to at least one end thereof as a coupling component, and specific examples of such an azo dye are described in JP-A-2002- 371214.
  • the third preferred structural characteristic is that the chromophore has an aromatic cyclic amino group or heterocyclic amino group structure, and specific examples ofthe chromophore include anilino group, and heterylamino group.
  • the fourth preferred structural characteristic is that the azo dye has a stereostructure. This is described in detail in Japanese Patent Application 2002-12015.
  • the oxidation potential ofthe dye can be raised, making it possible to enhance the ozone fastness thereof.
  • a means of raising the oxidation potential there may be used a metliod involving the removal of ⁇ -hydrogen from the azo dye.
  • an azo dye ofthe general formula (1-3) is particularly preferred. The means of raising the oxidation potential of an azo dye is described in detail in Japanese Patent Application 2001-254878.
  • the magenta ink ofthe present invention comprising an azo dye having the aforesaid characteristics preferably has ⁇ max (maximal absorption wavelength) of from 500 to 580 nm from the standpoint of hue and has a small half-width on both the long and short wavelengths, i.e., sharp absorption spectrum. This is described in detail in JP-A-2002-309133. Further, if an azo dye ofthe general formula (1-3) is used, by introducing methyl group at ⁇ -position, the sharpening of absorption can be realized.
  • the forced fading rate constant ofthe magenta ink comprising the azo dye with respect to ozone gas is preferably not greater than 5.0 x 10 "2 [h 1 ], more preferably not greater than 3.0 x 10 '2 [h “1 ], particularly not greater than 1.5 x 10 "2 [h “1 ].
  • the forced fading rate constant with respect to ozone gas only the magenta ink is printed on a reflective image medium to obtain an image.
  • the color ofthe main spectral absorption range of the ink constituting the image is measured for reflection density through a Status A filter.
  • the colored area at which the reflection density thus measured ranges from 0.90 to 1.10 is predetermined to be initial density point.
  • the image is then allowed to fading.
  • the time required until the reflection density ofthe initial density point reaches 80% ofthe initial value is then measured.
  • the reciprocal of this value [h "1 ] is the determined.
  • this reciprocal is determined as fading reaction rate constant.
  • the print patch for test employable herein include patch having solid rectangular symbols printed thereon according to JIS code 2223, stepwise color patch of Macbeth chart, and other arbitrary stepwise density patches allowing the measurement of area.
  • the reflection density of reflected image (stepwise color patch) printed for measurement is determined by measuring light ray passing through a Status A filter by a densitometer satisfying IS05-4.
  • the testing chamber for measuring the forced fading rate constant with respect to ozone gas is equipped with an ozone generator (e.g., of high voltage discharge type which applies ac voltage to dried air) capable of keeping the ozone gas concentration in the testing chamber at 5 mg L.
  • the aeration temperature is adjusted to 25°C.
  • the forced fading rate constant is a measure of oxidizability by ambient oixidizing atmosphere such as photochemical smog, automobile emission, organic vapor from coated surface of furniture or carpet and gas generated inside frame in daylight. Ozone gas represents these oxidizing atmospheres.
  • R 35 and R 36 each independently represent a hydrogen atom or a substituent which represents an aliphatic group, aromatic group, heterocyclic ring, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group or sulfamoyl group the hydrogen atom of which may be substituted.
  • G 3 , R 31 and R 32 each independently represent a hydrogen atom or a substituent which represents a halogen atom, aliphatic group, aromatic group, heterocyclic ring, cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, acyl group, hydroxy group, alkoxy group, aryloxy group, heterocyclic oxy group, silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, acylamino group, ureido group, sulfamoylamino group, alkoxycarbonylamino group, aiyloxycarbonylamino group, alkylsulfonylamino group, arylsulfonylamino group, heterocyclic sulfonylamino group, nitro group, al
  • R 3 ⁇ and R 35 or R 35 and R 36 may be connected to each other top form a 5- or 6-membered ring.
  • a 3 ⁇ represents a 5-membered heterocyclic ring and examples of hetero atoms in the heterocyclic ring include N, O and S.
  • the 5-membered heterocyclic ring is preferably a nitrogen- containing 5-membered heterocyclic ring which may be condensed with aliphatic rings, aromatic rings or other heterocyclic rings.
  • a 3 ⁇ may include pyrazole ring, imidazole ring, thiazole ring, isothiazole ring, thiadiazole ring, benzothiazole ring, benzooxazole ring, and benzoisothiazole ring.
  • the various heterocyclic groups may further have substituents. Preferred among these heterocyclic rings are pyrazole ring, imidazole ring, isothiazole ring, thiadiazole ring and benzothiazole ring represented by the following general formulae (a) to (f): (a) (b)
  • R 30 7 to R 32 o represent the same substituents as G 3 , R 31 and R 32 in the general formula (1-3).
  • Preferred among the compounds ofthe general formulae (a) to (f) are pyrazole ring represented by the general formula (a) and isothiazole ring represented by the general formula (b), most preferably pyrazole ring represented by the general formula (a).
  • Preferred examples of R 35 and R 3 ⁇ may include hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, alkylsulfonyl group or arylsulfonyl group.
  • R 35 and R 36 each are a hydrogen atom, aromatic group, heterocyclic group, acyl group, alkylsulfonyl group or arylsulfonyl group. Most preferably, R 35 and R 36 each are a hydrogen atom, aryl group or heterocyclic group. The hydrogen atom of the aforementioned various substituents may be substituted. However, R 35 and R 36 are not a hydrogen atom at the same time.
  • G 3 is preferably a hydrogen atom, halogen atom, aliphatic group, aromatic group, hydroxy group, alkoxy group, aryloxy group, acyloxy group, heterocyclic oxy group, amino group, acylamino group, ureido group, sulfamoylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkylthio group, arylthio group or heterocyclic thio group, more preferably a hydrogen atom, halogen atom, alkyl group, hydroxy group, alkoxy group, aryloxy group, acyloxy group, amino group or acylamino group, most preferably a hydrogen atom, amino group (preferably anilino group) or acylamino group.
  • the hydrogen atom ofthe aforesaid substituents may be substituted.
  • Preferred examples of R 31 and R 32 include hydrogen atom, alkyl group, halogen atom, alkoxycarbonyl group, carboxyl group, carbamoyl group, hydroxy group, alkoxy group, and cyano group.
  • the hydrogen atom ofthe aforesaid substituents maybe substituted.
  • R 31 and R 35 or R 35 and R 36 may be connected to each other to form a 5- or 6-membered ring. Examples ofthe substituents which may substitute on A 3 ⁇ or which may substitute on the substituents of R 31 , R 32 , 35 or G 3 include those listed above with reference to G 3 , R 3X and R 32 .
  • an ionic hydrophilic group is further provided on any position on A 31 , R 3 ⁇ , R 32 , R 35 , R 36 and G 3 as a substituent.
  • the ionic hydrophilic group as a substituent include sulfo group, carboxyl group, phosphono group, quaternary ammonium group, etc.
  • the aforesaid ionic hydrophilic group is preferably a carboxyl group, phosphono group or sulfo group, particularly carboxyl group or sulfo group.
  • the carboxyl group, phosphono group and sulfo group may be in the form of salt, and examples of counter ions constituting the salt include ammonium ion, alkaline metal ion (e.g., lithium ion, sodium ion, potassium ion), and organic cation (e.g., tetramethylammonium ion, tetramethylguanidium ion, tetramethyl phosphonium).
  • alkaline metal ion e.g., lithium ion, sodium ion, potassium ion
  • organic cation e.g., tetramethylammonium ion, tetramethylguanidium ion, tetramethyl phosphonium.
  • the terms (substituent) as used in the description ofthe general formula (1-3) will be described. These terms are common even to the general formula (1-3) and the general formula (3-A) described later.
  • the halogen atom include fluorine
  • the aliphatic group means alkyl group, substituted alkyl group, alkenyl group, substituted alkenyl group, alkinyl group, substituted alkinyl group, aralkyl group and substituted aralkyl group.
  • substituted as used in "substituted alkyl group", etc. means that the hydrogen atom in "alkyl group", etc. is substituted by substituents listed above with reference to G 3 , R 3 ⁇ and R 32 , etc.
  • the aliphatic group may have branches or may form a ring.
  • the number of carbon atoms in the aliphatic group is preferably from 1 to 20, more preferably from 1 to 16.
  • the aryl moiety ofthe aralkyl group or substituted aralkyl group is preferably a phenyl group or naphthyl group, particularly phenyl group.
  • the aliphatic group include methyl group, ethyl group, butyl group, isopropyl group, t-butyl group, hydroxyethyl group, methoxyethyl group, cyanoethyl group, trifluoroinetliyl group, 3-sulfopropyl group, 4- sulfobutyl group, cyclohexyl group, benzyl group, 2-phenethyl group, vinyl group, and allyl group.
  • the aromatic group means an aryl group or substituted aryl group.
  • the aryl group is preferably a phenyl group or naphthyl group, particularly phenyl group.
  • the number of carbon atoms in the aromatic group is preferably from 6 to 20, more preferably from 6 to 16.
  • Examples ofthe aromatic group include phenyl group, p-tollyl group, p-methoxyphenyl group, 0- chlorophenyl group, and m-(3-sulfopropylamino)phenyl group.
  • the heterocyclic group include substituted heterocyclic groups.
  • the heterocyclic group may have its heterocyclic ring condensed with aliphatic rings, aromatic rings or other heterocyclic rings.
  • the aforesaid heterocyclic group is preferably a 5- or 6-membered heterocyclic ring.
  • substituents include aliphatic group, halogen atom, alkylsulfonyl group, arylsulfonyl group, acyl group, acylamino group, sulfamoyl group, carbamoyl group, ionic hydrophilic group, etc.
  • heterocyclic group include 2-pyridyl group, 2-thienyl group, 2-thiazolyl group, 2-benzothiazolyl group, 2- benzooxazolyl group, and 2-furyl group.
  • Examples ofthe carbamoyl group include substituted carbamoyl groups.
  • Examples ofthe aforesaid substituents include alkyl group.
  • Examples ofthe aforesaid carbamoyl group include methylcarbamoyl group, and dimethylcarbamoyl group.
  • Examples ofthe alkoxycarbonyl group include substituted alkoxycarbonyl groups.
  • the aforesaid alkoxycarbonyl group is preferably an alkoxycarbonyl group having from 2 to 20 carbon atoms.
  • Examples of the aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkoxycarbonyl group include methoxycarbonyl group, and ethoxycarbonyl group.
  • Examples of he aryloxycarbonyl group include substituted aryloxycarbonyl groups.
  • the aforesaid aryloxycarbonyl group is preferably an aryloxycarbonyl group having from 7 to 20 carbon atoms.
  • Examples of the aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid aryloxycarbonyl group include phenoxycarbonyl group.
  • Examples ofthe heterocyclic oxycarbonyl group include substituted heterocyclic oxycarbonyl groups. Examples ofthe heterocyclic ring include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic oxycarbonyl group is preferably a heterocyclic oxycarbonyl group having from 2 to 20 carbon atoms.
  • the aforesaid substituents include ionic hydrophilic groups.
  • the aforesaid heterocyclic oxycarbonyl group include 2-pyridyloxycarbonyl group.
  • the acyl group include substituted acyl groups.
  • the aforesaid acyl group is preferably an acyl group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • the aforesaid acyl group include acetyl group and benzoyl group.
  • Examples ofthe alkoxy group include substituted alkoxy groups.
  • Examples ofthe aforesaid alkoxy group is preferably an alkoxy group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkoxy groups, hydroxyl groups, and ionic hydrophilic groups.
  • Examples ofthe aforesaid alkoxy group include methoxy group, ethoxy group, isopropoxy group, methoxyethoxy group, hydroxyethoxy group, and 3- carboxypropoxy group.
  • Examples ofthe aryloxy group include substituted aryloxy groups.
  • the aforesaid aryloxy group is preferably an aryloxy group having from 6 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkoxy groups, and ionic hydrophilic groups.
  • Examples ofthe aforesaid aryloxy group include phenoxy group, p-methoxyphenoxy group, and o-methoxyphenoxy group.
  • Examples ofthe heterocyclic oxy group include substituted heterocyclic oxy groups. Examples ofthe heterocyclic ring include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic oxy group is preferably a heterocyclic oxy group having from 2 to 20 carbon atoms. Examples ofthe aforesaid substituents include alkyl groups, alkoxy group, and ionic hydrophilic groups.
  • Examples ofthe aforesaid heterocyclic oxy group include 3-pyridyloxy group, and 3-thienyloxy group.
  • the silyloxy group is preferably a silyloxy group substituted by an aliphatic or aromatic group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid sjlyloxy group include trimethylsilyloxy, and diphenylmethyl silyloxy.
  • Examples ofthe acyloxy group include substituted acyloxy groups.
  • the aforesaid acyloxy group is preferably an acyloxy group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples of the aforesaid acyloxy group include acetoxy group, and benzoyloxy group.
  • the carbamoyloxy group include substituted carbamoyloxy groups.
  • Examples ofthe aforesaid substituents include alkyl groups.
  • Examples ofthe aforesaid carbamoyloxy group include N- methylcarbamoyloxy group.
  • Examples ofthe alkoxycarbonyloxy group include substituted alkoxycarbonyloxy groups.
  • the aforesaid alkoxycarbonyloxy group is preferably an alkoxycarbonyloxy group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid alkoxycarbonyloxy group include methoxycarbonyloxy group, and isopropoxycarbonyloxy group.
  • Examples ofthe aryloxycarbonyloxy group include substituted aryloxycarbonyloxy groups.
  • the aforesaid aryloxycarbonyloxy group is preferably an aryloxycarbonyloxy group having from 7 to 20 carbon atoms.
  • Examples ofthe aforesaid aryloxycarbonyloxy group includephenoxycarbonyloxy group.
  • Examples ofthe amino group include substituted amino groups.
  • Examples ofthe aforesaid substituents include alkyl groups, aryl groups, and heterocylic groups, and the alkyl groups, aryl groups and heterocyclic groups may further have substituents.
  • Examples ofthe alkylamino group include substituted alkylamino groups.
  • the alkylamino group is preferably an alkylamino group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkylamino group include methylamino group, and diethylamino group.
  • Examples ofthe arylamino group include substituted arylamino groups.
  • the aforesaid arylamino group is preferably an arylamino group having from 6 to 20 carbon atoms.
  • the aforesaid substituents include halogen atoms, and ionic hydrophilic groups.
  • Examples ofthe aforesaid arylamino group include phenylamino group, and 2-chlorophenylamino group.
  • Examples ofthe heterocyclic amino group include substituted heterocyclic amino groups. Examples of the heterocyclic ring include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic amino group is preferably a heterocyclic amino group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkyl groups, halogen atoms, and ionic hydrophilic groups.
  • Examples ofthe acylamino group include substituted acrylamino groups.
  • the aforesaid acylamino group is preferably an acylamino group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid acylamino group include acetylamino group, propionylamino group, benzoylamino group, N-phenylacetylamino group, and 3,5-disulfobenzoylamino group.
  • Examples ofthe ureido group include substituted ureido groups.
  • the aforesaid ureido group is preferably an ureido group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkyl groups, and aryl groups.
  • Examples ofthe aforesaid ureido group include 3-methylureido group, 3,3- dimethylureido group, and 3-phenylureido group.
  • Examples ofthe sulfamoylamino group include substituted sulfamoylamino groups.
  • Examples ofthe aforesaid substituents include alkyl groups.
  • Examples ofthe aforesaid sulfamoylamino group include N,N- dipropylsulfamoylamino group.
  • Examples ofthe all oxycarbonylamino group include substituted alkoxycarbonylamino groups.
  • the aforesaid alkoxycarbonylamino group is preferably an alkoxycarbonylamino group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkoxycarbonylamino group include ethoxycarbonylamino groups.
  • Examples ofthe aryloxycarbonylamino group include substituted aryloxycarbonylamino groups.
  • the aforesaid aryloxycarbonylamino group is preferably an aryloxycarbonylamino group having from 7 to 20 carbon atoms.
  • the aforesaid substituents include ionic hydrophilic groups.
  • examples of he aforesaid aryloxycarbonylamino group include phenoxycarbonylamino groups.
  • Examples ofthe alkylsulfonylamino group and arylsulfonylamino group include substituted alkylsulfonylamino groups and substituted arylsulfonylamino groups.
  • the aforesaid alkylsulfonylamino group and arylsulfonylamino group are preferably an alkylsulfonylamino group and arylsulfonylamino group each having from 1 to 20 carbon atoms.
  • the substituents include ionic hydrophilic groups.
  • Examples of the aforesaid alkylsulfonylamino group and arylsulfonylamino group include methylsulfonylamino group, N- phenyl-methyl sulfonylamino group, phenylsulfonyl amino group, and 3-carboxyphenylsulfonyl amino group.
  • heterocyclic sulfonylamino group examples include substituted sulfonylamino groups.
  • the heterocyclic ring examples include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic sulfonylamino group is preferably a heterocyclic sulfonylamino group having from 1 to 12 carbon atoms.
  • the aforesaid substituents include ionic hydrophilic groups.
  • examples ofthe aforesaid heterocyclic sulfonylamino group include 2-thienylsulfonylamino group, and 3-pyridylsulfonyl amino group.
  • alkylthio group, arylthio group and heterocyclic thio group examples include substituted alkylthio group, substituted arylthio group, and substituted heterocyclic thio group.
  • heterocyclic ring examples include those listed above with reference to the heterocyclic group.
  • the aforesaid alkylthio group, arylthio group and heterocyclic thio group each preferably have from 1 to 20 carbon atoms.
  • substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkylthio group, arylthio group and heterocyclic thio group include methylthio group, phenylthio group, and 2-pyridylthio group.
  • Examples ofthe alkylsulfonyl group and arylsulfonyl group include substituted alkylsulfonyl groups and substituted arylsulfonyl groups.
  • Examples ofthe alkylsulfonyl group and arylsulfonyl group include methylsulfonyl group and phenylsulfonyl group, respectively.
  • Examples ofthe heterocyclic sulfonyl group include substituted heterocyclic sulfonyl groups.
  • heterocyclic ring examples include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic sulfonyl group is preferably a heterocyclic sulfonyl group having from 1 to 20 carbon atoms.
  • substituents include ionic hydrophilic groups.
  • examples ofthe aforesaid heterocyclic sulfonyl group include 2-tl ⁇ ienylsulfonyl group and 3-pyridylsulfonyl group.
  • alkylsulfinyl group and arylsulfinyl group include substituted alkylsulfinyl groups and substituted arylsulfinyl groups.
  • Examples ofthe alkylsulfinyl group and arylsulfinyl group include methylsulfinyl group and phenylsulfinyl group, respectively.
  • Examples ofthe heterocyclic sulfinyl group include substituted heterocyclic sulfinyl groups.
  • Examples ofthe heterocyclic ring include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic sulfinyl group is preferably a heterocyclic sulfinyl group having from 1 to 20 carbon atoms. Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • heterocyclic sulfinyl group examples include 4-pyridylsulfinyl group.
  • the sulfamoyl group include substituted sulfamoyl groups.
  • the aforesaid substituents include alkyl groups.
  • the aforesaid sulfamoyl group include dimethylsulfamoyl group, and di-(2-hydroxyethyl)sulfamoyl group.
  • Particularly preferred among the structures ofthe general formula (1-3) is one represented by the following general formula (3-A).
  • general formula (3-A) wherein R 3J , R 32 , R 35 and R 36 are as defined in the general formula (1-3).
  • R 33 and R 34 each independently represent a hydrogen atom or a substituent which represents an aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group or sulfamoyl group. Prefe ⁇ ed among these substituents is hydrogen atom, aromatic group, heterocyclic group, acyl group, alkylsulfonyl group or arylsulfonyl group, particularly hydrogen atom, aromatic group and heterocyclic group.
  • Z 31 represents an electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.20 or more.
  • Z 3 ⁇ is preferably an electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.30 or more, more preferably 0.45 or more, particularly 0.60 or more, but the Hammett's substituent constant ⁇ p ofthe electron-withdrawing group is preferably not greater than 1.0.
  • the electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.60 or more include cyano group, nitro group, alkylsulfonyl group (e.g., methylsulfonyl group), and arylsulfonyl group (e.g., phenylsulfonyl group).
  • Examples ofthe electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.45 or more include acyl group (e.g., acetyl group), alkoxycarbonyl group (e.g., dodecyloxycarbonyl group), aryloxycarbonyl group (e.g., m-chlorophenoxycarbonyl), alkylsulfinyl group (e.g., n-propylsulfinyl), arylsulfinyl group (e.g., phenylsulfinyl), sulfamoyl group (e.g., N-ethylsulfamoyl, N,N-dimethylsulfamoyl), and halogenated alkyl group (e.g., trifluoromethyl) besides the aforesaid groups.
  • acyl group e.g., acetyl group
  • Examples ofthe electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.30 or more include acyloxy group (e.g., acetoxy group), carbamoyl group (e.g., N-ethylcarbamoyl, N,N- dibutylcarbamoyl), halogenated alkoxy group (e.g., trifluoromethyloxy), halogenated aryloxy group (e.g., pentafluorophenyloxy), sulfonyloxy group (e.g., metliylsulfonyloxy), halogenated aU lthio group (e.g., difluoromethyltliio), aryl group substituted by two or more electron-witlidrawing groups having ⁇ p of 0.15 or more (e.g., 2,4-dinitrophenyl, pentachlorophenyl), and heterocyclic group (e.g., 2-benz
  • the electron-withdrawing group having ⁇ p of 0.20 or more include halogen atoms besides the aforesaid groups.
  • halogen atoms besides the aforesaid groups.
  • Prefe ⁇ ed among these groups are C 2 -C 20 acyl group, C 2 -C 2u alkyloxycarbonyl group, nitro group, cyano group, C ⁇ -C 20 alkylsulfonyl group, C 6 -C 2 o arylsulfonyl group, C ⁇ -C 20 carbamoyl group, and C ⁇ -C 20 halogenated alkyl group.
  • Z 32 represents a hydrogen atom or a substituent and the substituent represents an aliphatic group, aromatic group or heterocyclic group.
  • Z 32 is preferably an aliphatic group, more preferably a -C ⁇ alkyl group.
  • Q represents a hydrogen atom or a substituent and the substituent represents an aliphatic group, aromatic group or heterocyclic group.
  • Q is preferably a group formed by a group of non-metallic atoms required to form a 5- to 8-membered ring.
  • the aforementioned 5- to 8-membered ring may be substituted, may be a saturated ring or may have an unsaturated bond. Particularly preferred among these 5- to 8-membered rings are aromatic group and heterocyclic group. Prefe ⁇ ed examples ofthe non-metallic atom include nitrogen atom, oxygen atom, sulfur atom, and carbon atom.
  • cyclic structures include benzene ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, cyclohexene ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, imidazole ring, benzoimidazole ring, oxazole ring, benzoxazole ring, thiazole ring, benzothiazole ring, oxane ring, sulfolane ring, and thiane ring.
  • R 35 and R 36 each are preferably a hydrogen atom, alkyl group, aryl group, heterocyclic group, sulfonyl group or acyl group, more preferably hydrogen atom, aryl group, heterocyclic group or sulfonyl group, most preferably hydrogen atom, aryl group or heterocyclic group.
  • R 35 and R 3 6 are not a hydrogen atom at the same time.
  • G 3 is preferably a hydrogen atom, halogen atom, alkyl group, hydroxyl group, amino group or acylamino group, more preferably hydrogen atom, halogen atom, amino group or acylamino group, most preferably hydrogen atom, amino group or acylamino group.
  • a 3 ⁇ is preferably a pyrazole ring, imidazole ring, isothiazole ring, thiadiazole ring or benzothiazole ring, more preferably pyrazole ring or isothiazole ring, most preferably pyrazole ring.
  • At least one ofthe various substituents is preferably a compound which is a preferred group as mentioned above, and more preferably, more ofthe various substituents are compounds which are prefe ⁇ ed groups as mentioned above, and most preferably, all the various substituents are compounds which are prefe ⁇ ed groups as mentioned above.
  • Specific examples ofthe azo dye represented by the general formula (1-3) will be given below, but the azo dye to be used in the present invention is not limited to the following examples.
  • the content of the azo dye represented by the general formula (1-3) in the ink is preferably from 0.2% weight, more preferably from 0.5% to 15% by weight.
  • SUBSTITUTE S ⁇ EET(RULE26) state) ofthe azo dye represented by the general formula (1-3) in water at 20°C is preferably 5% by weight or more, more preferably 10% by weight or more.
  • Black dye As the black ink to be used in the invention there is used a dye (L) having a wavelength ⁇ max of from 500 nm to 700 nm and a half width (W ⁇ , 1/2) of 100 nm or more (preferably from not lower than 120 nm to not higher than 500 nm, preferably from not lower than 120 nm to not higher than 350 nm) in absorption spectrum of a diluted solution normalized to absorbance of 1.0.
  • this dye (L) alone can be used as a dye for black ink.
  • this dye (L) is used in combination with dyes which compensate the dye (L) in the wavelength range where the dye (L) has a low absorption. It is normally preferred that the dye (L) be used in combination with a dye (S) having main absorption in yellow range ( ⁇ max of from 350 to 500 nm). The dye (L) may also be used in combination with other dyes to prepare a black ink.
  • these dyes are dissolved or dispersed in an aqueous medium singly or in admixture to prepare a black ink.
  • desired requirements i.e., (1) excellent weather resistance and or (2) maintenance of black balance even after fading
  • an ink satisfying the following requirements be prepared.
  • solid rectangle number of JIS code 2223 is printed at 48 points.
  • the print thus formed is then measured for reflection density (Dvis) through a Status A filter (visual filter).
  • the reflection density thus measured is defined as initial density.
  • X-rite densitometer As a reflection densitometer having a Status A filter mounted thereon there may be used, X-rite densitometer.
  • the black ink preferably exhibits a forced fading rate constant (kvis) of not higher than 5.0 x 10 -2 [h _1 ], more preferably not higher than 3.0 x 10 "2 [h “1 ], particularly not higher than 1.0 x 10 "2 [h “1 ] (Condition 1).
  • solid rectangle number of JIS code 2223 is printed at 48 points.
  • the print thus formed is then measured for three color (C (cyan), M (magenta), Y (yellow)) reflection densities (D R , D G , D B ), which are not Dvis, through a Status A filter.
  • the reflection densities thus measured each are defined as initial densities.
  • D R , D G , D B indicate C reflection density through a red filter, M reflection density through a green filter and Y reflection density through a blue filter, respectively.
  • This printed matter is then forcedly faded using an ozone fading tester capable of always generating 5 ppm of ozone in the aforementioned manner.
  • the forced fading rate constants (k R , ko, k B ) are then similarly determined from the time required until the reflection densities (D R , D G , D B ) reach 80% ofthe initial value.
  • the "printed matter obtained by printing a solid rectangle of JIS code 2223 at 48 points" as used hereinabove has a size large enough to cover the aperture ofthe measuring instrument so that a sufficiently large area can be used for density measurement.
  • At least one dye to be used in the black ink has an oxidation potential of more positive than 1.0 V (vs SCE), preferably more positive than 1.1 V (vs SCE), more preferably more positive than 1.2 V (vs SCE) and most preferably more than 1.25 V (vs SCE), and at least one ofthe dyes has ⁇ max of 500 nm or more (Condition 3).
  • the black ink is prepared using the azo dye represented by the general formula (1-4).
  • Examples ofthe azo dye represented by the general formula (1-4) include those corresponding to the dye (L) having ⁇ max of 500 nm to 700 nm and a half width of 100 nm or more in absorption spectrum of a diluted solution normalized to absorbance of 1.0.
  • the dye (S) having ⁇ max of 350 nm to 500 nm is similarly included as one corresponding to the dye ofthe general formula (1-4).
  • at least one ofthe dye (L) is the dye ofthe general formula (1-4), and particularly preferably, at least one of both the dye (L) and the dye (S) are the dyes ofthe general formula (1-4), and among them, it is preferred that the dye ofthe general formula (1-4) amounts 90% by mass ofthe total dyes in the ink (Condition 4).
  • the black ink according to the invention is a black ink that satisfies at least one ofthe conditions 1 to 4.
  • the dye represented by the general formula (1-4) will be described hereinafter.
  • a 4 ⁇ , B 4i and C 4 ⁇ each independently represent an aromatic or heterocyclic group which may be substituted (A 41 and Gu each are a monovalent group and B 4 ⁇ is a divalent group).
  • the substituent on A 41 , B 41 and C 41 may be an aromatic azo group or heterocyclic azo group.
  • the azo dye represented by the general formula (1-4) is particularly preferably a dye represented by the following general formula (4-A).
  • a 41 and B 41 are as defined in the general formula (1-4).
  • B 42 and B 43 each represent or
  • G 4 , R 41 and R 42 each independently represent a hydrogen atom, a halogen atom or an aliphatic group, aromatic group, heterocyclic group, cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, acyl group, hydroxyl group, alkoxy group, aryloxy group, heterocyclic oxy group, silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxy carbonyloxy group, amino group (including arylamino group and heterocyclic amino group), acylamino group, ureido group, sulfamonylamino group, alkoxycarbonyl amino group, aryloxycarbonylamino group, alkyl sulfonylamino group, arylsulfonylamino group, heterocyclic sulf
  • R45 and R 4 6 each independently represent a hydrogen atom, or an aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxy carbonyloxy group, carbamolyl group, alkylsulfonyl group, arylsulfonyl group or sulfamoyl group which may be further substituted, with the proviso that R 4 5 and ⁇ are not a hydrogen atom at the same time.
  • R 41 and R 45 or R 45 and 46 may be connected to each other to form a 5- or 6-membered ring.
  • the azo dye represented by the general formula (4-A) is preferably a dye represented by the following general formula (4-B).
  • R 4 7 and R 48 have the same meaning as R 41 in the general formula (4-A).
  • the terms (substituent) used with reference to the general formulae (1-4), (4-A) and (4-B) will be described hereinafter. These terms apply also to the general formulae (4-C) and (4-D).
  • Examples ofthe halogen atom include fluorine atom, chlorine atom, and bromine atom.
  • the aliphatic group means alkyl group, substituted alkyl group, alkenyl group, substituted alkenyl group, alkinyl group, substituted alkinyl group, aralkyl group and substituted aralkyl group.
  • the aliphatic group may have branches or may form a ring.
  • the number of carbon atoms in the aliphatic group is preferably from 1 to 20, more preferably from 1 to 16.
  • the aryl moiety ofthe aralkyl group or substituted aralkyl group is preferably a phenyl group or naphthyl group, particularly phenyl group.
  • Examples ofthe aliphatic group include methyl group, ethyl group, butyl group, isopropyl group, t-butyl group, hydroxyethyl group, methoxyethyl group, cyanoethyl group, trifluoromethyl group, 3-sulfopropyl group, 4-sulfobutyl group, cyclohexyl group, benzyl group, 2-phenethyl group, vinyl group, and allyl group.
  • the monovalent aromatic group means an aryl group or substituted aryl group.
  • the aryl group is preferably phenyl or naphthyl, particularly phenyl.
  • the number of carbon atoms in the monovalent aromatic group is preferably from 6 to 20, more preferably from 6 to 16.
  • the monovalent aromatic group include phenyl, p-tollyl, p-methoxyphenyl, o-chlorophenyl, and m-(3-sulfopropylamino)phenyl.
  • the divalent aromatic group is obtained by making the monovalent aromatic group divalent. Examples ofthe divalent aromatic group include phenylene, p-tollylene, p-methoxyphenylene, o-chlorophenylene, m-(3- sulfopropylamino)phenylene, and naphthylene.
  • heterocyclic group examples include substituted and unsubstituted heterocyclic groups.
  • the heterocyclic group may have its heterocyclic ring condensed with aliphatic rings, aromatic rings or other heterocyclic rings.
  • the aforesaid heterocyclic group is preferably a 5- or 6-membered heterocyclic ring.
  • the hetero atom in the heterocycle include nitrogen, oxygen and sulfur atoms.
  • the aforesaid substituents include aliphatic group, halogen atom, alkylsulfonyl group, arylsulfonyl group, acyl group, acylamino group,, sulfamoyl group, carbamoyl group, ionic hydrophilic group, etc.
  • Examples ofthe heterocycle in the monovalent and divalent heterocyclic groups include pyridine, thiophene, thiazole, benozothiazole, benzoxazole, and furane ring.
  • Examples ofthe carbamoyl group include substituted and unsubstituted carbamoyl groups.
  • Examples ofthe substituents on the carbamoyl group include alkyl groups.
  • Examples ofthe carbamoyl group include methylcarbamoyl group, and dimethylcarbamoyl group.
  • Examples ofthe alkoxycarbonylamino group include substituted and unsubstituted alkoxycarbonylamino groups. These alkoxycarbonylamino groups each preferably have from 2 to 20 carbon atoms.
  • Examples ofthe substituents on the a&oxycarbonylamino group include ionic hydrophilic groups.
  • the alkoxycarbonylamino group include methoxycarbonylamino, and ethoxycarbonylamino.
  • the aryloxycarbonyl group include substituted aryloxycarbonyl group and unsubstituted aryloxycarbonyl group.
  • the aforesaid aryloxycarbonyl group is preferably an aryloxycarbonyl group having from 7 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents on aryloxycarbonyl group include ionic hydrophilic groups. Examples ofthe aforesaid aryloxycarbonyl group include phenoxycarbonyl group.
  • heterocyclic oxycarbonyl group examples include substituted heterocyclic oxycarbonyl group and unsubstituted heterocyclic oxycarbonyl group.
  • the aforesaid heterocyclic oxycarbonyl group is preferably a heterocyclic oxycarbonyl group having from 2 to 20 carbon atoms.
  • substituents include ionic hydrophilic groups.
  • examples ofthe aforesaid heterocyclic oxycarbonyl group include 2- pyridyloxycarbonyl group.
  • the acyl group include substituted acyl group and unsubstituted acyl group.
  • the aforesaid acyl group is preferably an acyl group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid acyl group include acetyl group and benzoyl group.
  • Examples ofthe alkoxy group include substituted alkoxy group and unsubstituted alkoxy group.
  • Examples ofthe aforesaid alkoxy group is preferably an alkoxy group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkoxy groups, hydroxyl groups, and ionic hydrophilic groups.
  • Examples ofthe aforesaid alkoxy group include methoxy group, ethoxy group, isopropoxy group, methoxyethoxy group, hydroxyethoxy group, and 3-carboxypropoxy group.
  • Examples of he aryloxy group include substituted aryloxy group and unsubstituted aryloxy group.
  • the aforesaid aryloxy group is preferably an aryloxy group having from 6 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkoxy groups, and ionic hydrophilic groups.
  • Examples ofthe aforesaid aryloxy group include phenoxy group, p-methoxyphenoxy group, and o-methoxyphenoxy group.
  • Examples ofthe heterocyclic oxy group include substituted heterocyclic oxy group and unsubstituted heterocyclic oxy group.
  • the aforesaid heterocyclic oxy group is preferably a heterocyclic oxy group having from 2 to 20 carbon atoms.
  • substituents include alkyl group, alkoxy group, and ionic hydrophilic groups.
  • heterocyclic oxy group include 3-pyridyloxy group, and 3- thienyloxy group.
  • the silyloxy group is preferably a silyloxy group substituted by an aliphatic or aromatic group having from 1 to 20 carbon atoms. Examples ofthe aforesaid silyloxy group include trimetliylsilyloxy, and diphenylmethyl silyloxy.
  • Examples ofthe acyloxy group include substituted acyloxy group and unsubstituted acyloxy group.
  • the aforesaid acyloxy group is preferably an acyloxy group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid acyloxy group include acetoxy group, and benzoyloxy group.
  • Examples ofthe carbamoyloxy group include substituted carbamoyloxy groups.
  • Examples ofthe aforesaid substituents include alkyl groups. Examples ofthe aforesaid carbamoyloxy group include N- methylcarbamoyloxy group.
  • Examples ofthe alkoxycarbonyloxy group include substituted alkoxycarbonyloxy group and unsubstituted alkoxycarbonyloxy group.
  • the aforesaid alkoxy carbonyloxy group is preferably an alkoxycarbonyloxy group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid alkoxycarbonyloxy group include methoxycarbonyloxy group, and isopropoxycarbonyloxy group.
  • Examples ofthe aryloxycarbonyloxy group include substituted aryloxycarbonyloxy group and unsubstituted aryloxycarbonyloxy group.
  • the aforesaid aryloxy carbonyloxy group is preferably an aryloxycarbonyloxy group having from 7 to 20 carbon atoms.
  • Examples ofthe aforesaid aryloxycarbonyloxy group include phenoxycarbonyloxy group.
  • the amino group include substituted amino group and unsubstituted amino group.
  • Examples ofthe aforesaid substituents include alkyl groups, aryl groups, and heterocylic groups, and the alkyl groups, aryl groups and heterocyclic groups may further have substituents.
  • the alkylamino group is preferably an alkylamino group having from 1 to 20 carbon atoms. Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkylamino group include methylamiiio group, and diethylamino group.
  • Examples ofthe arylamino group include substituted arylamino group and unsubstituted arylamino group.
  • the aforesaid arylamino group is preferably an arylamino group having from 6 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include halogen atoms, and ionic hydrophilic groups.
  • Examples ofthe aforesaid arylamino group include anilino group, and 2-cUorophenylamino group.
  • Examples ofthe heterocyclic amino group include substituted heterocyclic amino group and unsubstituted heterocyclic amino group.
  • the aforesaid heterocyclic amino group is preferably a heterocyclic amino group having from 2 to 20 carbon atoms.
  • the aforesaid substituents include alkyl groups, halogen atoms, and ionic hydrophilic groups.
  • the acylamino group include substituted acylamino group and unsubstituted acylamino group.
  • the aforesaid acylamino group is preferably an acylamino group having from 2 to 20 carbon atoms. Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid acylamino group include acetylamino group, propionylamino group, benzoylamino group, N-phenylacetylamino group, and 3,5-disulfobenzoylamino group.
  • Examples ofthe ureido group include substituted and unsubstituted ureido groups. These ureido groups each preferably have from 1 to 20 carbon atoms. Examples ofthe substituents on the ureido group include alkyl groups, and aryl groups. Examples ofthe ureido group include 3-methylureide group, 3,3-dimethylureido group, and 3-phenylureido group.
  • Examples ofthe sulfamoylamino group include substituted sulfamoylamino group and unsubstituted sulfamoylamino group.
  • Examples ofthe aforesaid substituents include alkyl groups.
  • Examples ofthe aforesaid sulfamoylamino group include N,N-dipropyIsulfamoylamino group.
  • Examples of the alkoxycarbonylamino group include substituted alkoxycarbonylamino group and unsubstituted alkoxycarbonylamino group.
  • the aforesaid alkoxy carbonylamino group is preferably an alkoxycarbonylamino group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkoxycarbonylamino group include ethoxycarbonylamino groups.
  • Examples ofthe aryloxycarbonylamino group include substituted aryloxycarbonylamino group and unsubstituted aryloxycarbonylamino group.
  • the aforesaid aryloxycarbonylamino group is preferably an aryloxycarbonylamino group having from 7 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid aryloxycarbonylamino group include phenoxycarbonyl amino groups.
  • Examples ofthe aU-ylsulfonylamino group and arylsulfonylamino group include substituted alkylsulfonylamino groups and substituted arylsulfonylamino groups.
  • the aforesaid sulfonyl amino group is preferably a sulfonylamino group having from 1 to 20 carbon atoms.
  • Examples ofthe substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid sulfonyl groups include methylsulfonylamino group, N-phenyl- methyl sulfonylamino group, phenyl sulfonyl amino group, and 3-carboxyphenylsulfonyl amino group.
  • Examples ofthe heterocyclic sulfonyl group include substituted sulfonylamino group and unsubstituted sulfonylamino group.
  • the aforesaid heterocyclic sulfonyl group is preferably a heterocyclic sulfonylamino group having from 1 to 12 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid heterocyclic sulfonyl group include 2-thiophenesulfonyl group, and 3- pyridylsulfonyl group.
  • Examples ofthe heterocyclic sulfonyl group include substituted heterocyclic sulfonyl group and unsubstituted heterocyclic sulfonyl group.
  • the aforesaid heterocyclic sulfonyl group is preferably a heterocyclic sulfonyl group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • heterocyclic sulfonyl group examples include 2-thiophene sulfonyl group and 3-pyridylsulfonyl group.
  • heterocyclic sulfinyl group examples include substituted heterocyclic sulfinyl group and unsubstituted heterocyclic sulfinyl group.
  • the aforesaid heterocyclic sulfinyl group is preferably a heterocyclic sulfinyl group having from 1 to 20 carbon atoms.
  • substituents examples include ionic hydrophilic groups.
  • heterocyclic sulfinyl group examples include 4-pyridylsulfinyl group.
  • Examples ofthe alkyl group, aryl group and heterocyclic thio group include substituted alkyl, aryl and heterocyclic thio groups and unsubstituted alkyl, aryl and heterocyclic thio groups.
  • the alkyl, aryl and heterocyclic thio groups each preferably have from 1 to 20 carbon atoms.
  • Examples ofthe substituents on the alkyl, aryl and heterocyclic thio groups include ionic hydrophilic groups.
  • Examples ofthe alkyl, aryl and heterocyclic thio groups include metliylthio group, phenylthio group, and 2-pyridylthio group.
  • alkylsulfonyl and arylsulfonyl groups include substituted alkylsulfonyl and arylsulfonyl groups and unsubstituted alkylsulfonyl and arylsulfonyl groups.
  • alkylsulfonyl and arylsulfonyl groups include methylsulfonyl group and phenylsulfonyl group.
  • alkylsulfinyl and arylsulfinyl groups include substituted alkylsulfinyl and arylsulfinyl groups and unsubstituted alkylsulfinyl and arylsulfinyl groups.
  • alkylsulfinyl and arylsulfinyl groups include methylsulfinyl group and phenylsulfinyl group.
  • the sulfamoyl group include substituted and unsubstituted sulfamoyl groups.
  • substituents on the sulfamoyl group include alkyl groups.
  • sulfamoyl group examples include dimethylsulfamoyl group, and di-(2-hydroxyethyl)sulfamoyl group.
  • the general formulae (1-4), (4-A) and (4-B) will be further described hereinafter. Those described with reference to groups and substituents apply to the following description.
  • a 41 , B 41 and C ⁇ each independently represent an aromatic group (A41 and C 4 ⁇ each are a monovalent aromatic group such as aryl group; B 4J is a divalent aromatic group such as arylene group) which may be substituted or a heterocyclic group (A 1 and C 41 each are a monovalent heterocyclic group; B 41 is a divalent heterocyclic group) which may be substituted.
  • the aromatic ring include benzene ring, and naphthalene ring.
  • the hetero atoms in the heterocycle include nitrogen atom, oxygen atom, and sulfur atom.
  • the heterocyclic group may have aliphatic rings,- aromatic rings or other heterocycles condensed thereto.
  • the substituents may be arylazo groups or heterocyclic azo groups.
  • at least one of A ⁇ , B 4 ⁇ and C 41 is a heterocyclic group. More preferably, at least two of A 41 , B ⁇ and C 41 are heterocyclic groups. All of A 41 , B 41 and C 41 maybe heterocyclic groups.
  • a preferred example ofthe heterocyclic group represented by C 41 is an aromatic group-containing 6- membered heterocyclic group represented by the following general formula (4-C).
  • the general formula (1-4) corresponds to the general formula (4-A).
  • B 42 and B 43 each represent R 4 5 and R 4 6 each independently represent a hydrogen atom or an aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group or sulfamoyl group which may further have substituents.
  • Preferred examples ofthe substituents represented by R 4 5 and 6 include hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, ah lsulfonyl group, and arylsulfonyl group. More desirable among these substituents are hydrogen atom, aromatic group, heterocyclic group, acyl group, alkylsulfonyl group, and arylsulfonyl group. Most desirable among these substituents are hydrogen atom, aryl group, and heterocyclic group. These substituents may further have substituents. However, R 45 and R 6 are not a hydrogen atom at the same time.
  • G 4 , R 41 and 42 each independently represent a hydrogen atom, a halogen atom or an aliphatic group, aromatic group, heterocyclic group, cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, acyl group, hydroxyl group, alkoxy group, aryloxy group, heterocyclic oxy group, silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group (including alkylamino group, arylamino group and heterocyclic amino group), acylamino group, ureido group, sulfamonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkylsulfonylamino group, arylsulfonylamino group, heterocyclic sulf
  • Prefe ⁇ ed among the substituents represented by G 4 are hydrogen atom, halogen atom, aliphatic group, aromatic group, hydroxyl group, alkoxy group, aryloxy group, heterocyclic oxy group, amino group (including alkylamino group, arylamino group and heterocyclic amino group), acylamino group, ureido group, sulfamonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkylthio group, arylthio group, and heterocyclic thio group.
  • substituents More desirable among these substituents are hydrogen atom, halogen atom, alkyl group, hydroxyl group, alkoxy group, aryloxy group, acyloxy group, amino group (including alkylamino group, arylamino group and heterocyclic amino group) and acylamino group. Most desirable among these substituents are hydrogen atom, anilino group, and acylamino group. These groups may further have substituents.
  • substituents represented by R 41 and R 42 include hydrogen atom, alkyl group, halogen atom, alkoxycarbonyl group, carboxyl group, carbamoyl group, hydroxyl group, alkoxy group, and cyano group. These groups may further have substituents.
  • R 41 and R 42 or R 4 5 and R 6 may be connected to each other to form a 5- or 6-membered ring.
  • substituents on the substituents represented by A ⁇ , R 41 , R 42 , R 4 5, R 4 6 and G 4 include those listed with reference to G 4 , IL ⁇ , and R 42 .
  • a 41 , 1 ⁇ , R 42 , R 4 5, R 46 and G 4 preferably further have an ionic hydrophilic group in any position as substituent. Examples ofthe ionic hydrophilic group include sulfo group, carboxyl group, phosphono group, and quaternary ammonium group.
  • Prefe ⁇ ed among these ionic hydrophilic groups are carboxyl group, phosphono group, and sulfo group, and particularly prefe ⁇ ed among these ionic hydrophilic groups are carboxyl group and sulfo group.
  • the carboxyl group, phosphono group and sulfo group may be used in the form of salt.
  • the counter ion forming the salt include ammonium ion, alkaline metal ion (e.g., lithium ion, sodium ion, potassium ion), and organic cation (e.g., tetramethyl ammonium ion, tetramethylguanidium ion, tetramethyl phosphonium ion).
  • Prefe ⁇ ed among tliese counter ions is lithium ion.
  • Prefe ⁇ ed examples of the heterocyclic structure represented by B 4 ⁇ include thiophene ring, thiazole ring, imidazole ring, benzothiazole ring, and thienothiazole ring. These heterocyclic groups may further have substituents.
  • Prefe ⁇ ed among these heterocyclic groups are thiophene ring, thiazole ring, imidazole ring, benzothiazole ring, and thienothiazole ring represented by the following general formulae (h) to (1).
  • B 4 ⁇ is a thiophene ring represented by the general formula (h) and C ⁇ has a structure represented by the general formula (4-C)
  • the general formula (1-4) co ⁇ esponds to the general formula (4-B).
  • R 409 to R 41 7 have the same meaning as the substituents G 4 , R41 and R42 in the general formula (4-A).
  • Particularly prefe ⁇ ed among the dye structures represented by the general formula (4-B) is one represented by the following general formula (4-D).
  • Z 4 represents an electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.20 or more.
  • Z is preferably an electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.30 or more, more preferably 0.45 or more, particularly 0.60 or more, but the Hammett's substituent constant ⁇ p ofthe electron-withdrawing group is preferably not greater than 1.0.
  • the electron-witlidrawing group having a Hammett's substituent constant ⁇ p of 0.60 or more include cyano group, nitro group, alkylsulfonyl group (e.g., methylsulfonyl group), and arylsulfonyl group (e.g., phenylsulfonyl group).
  • Examples ofthe electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.45 or more include acyl group (e.g., acetyl group), alkoxycarbonyl group (e.g., dodecyloxycarbonyl group), aryloxycarbonyl group (e.g., m-chlorophenoxycarbonyl), alkylsulfinyl group (e.g., n-propylsulfinyl), arylsulfinyl group (e.g., phenylsulfinyl), sulfamoyl group (e.g., N-etliylsulfamoyl, N,N-dimethylsulfamoyl), and halogenated alkyl group (e.g., trifhioromethyi) besides the aforesaid groups.
  • acyl group e.g., acetyl group
  • Examples ofthe electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.30 or more include acyloxy group (e.g., acetoxy group), carbamoyl group (e.g., N-ethylcarbamoyl, N,N- dibutylcarbamoyl), halogenated alkoxy group (e.g., trifluoromethyloxy), halogenated aryloxy group (e.g., pentafluorophenyloxy), sulfonyloxy group (e.g., methylsulfonyloxy), halogenated alkylthio group (e.g., difluoromethylthio), aryl group substituted by two or more electron-withdrawing groups having ⁇ p of 0.15 or more (e.g., 2,4-dinitrophenyl, pentachlorophenyl), and heterocyclic group'(e.g., 2-benzooxazolyl, 2-
  • the electron-withdrawing group having ⁇ p of 0.20 or more include halogen atoms besides the aforesaid groups.
  • halogen atoms besides the aforesaid groups.
  • Prefe ⁇ ed among these groups are C 2 -C 2 o acyl group, C 2 -C 2 o alkyloxycarbonyl group, nitro group, cyano group, -C20 alkylsulfonyl group, C 6 -C 2 o arylsulfonyl group, C1-C20 carbamoyl group, and C 1 -C 2 0 halogenated alkyl group as Z 4 .
  • R 41 , R 42 , R 45 and R 4 6 in the general formula (4-D) are as defined in the general formula (4-A).
  • R 4 3 and R 44 each independently represent a hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group or sulfamoyl group.
  • Prefe ⁇ ed among these groups are hydrogen atom, aromatic group, heterocyclic group, acyl group, alkylsulfonyl group, and arylsulfonyl group. Particularly prefe ⁇ ed among these groups are hydrogen atom, aromatic group, and heterocyclic group.
  • the groups described with reference to the general formula (4-D) may further have substituents. In the case where these groups further have substituents, examples of these substituents include the substituents described with reference to the general formula (4-A) and the groups and ionic hydrophilic groups exemplified with reference to G 4 , R 41 and R42.
  • R 45 and R 6 each are preferably a hydrogen atom, alkyl group, aryl group, heterocyclic group, sulfonyl group or acyl group, more preferably hydrogen atom, aryl group, heterocyclic group or sulfonyl group, most preferably hydrogen atom, aryl group or heterocyclic group.
  • R 4 5 and R 46 are not a hydrogen atom at the same time.
  • G 4 is preferably a hydrogen atom, halogen atom, alkyl group, hydroxyl group, amino group or acylamino group, more preferably hydrogen atom, halogen atom, amino group or acylamino group, most preferably hydrogen atom, amino group or acylamino group.
  • n is preferably a pyrazole ring, imidazole ring, isothiazole ring, thiadiazole ring or benzothiazole ring, more preferably pyrazole ring or isothiazole ring, most preferably pyrazole ring.
  • At least one ofthe various substituents is preferably a compound which is a prefe ⁇ ed group as mentioned above, and more preferably, more ofthe various substituents are compounds which are prefe ⁇ ed groups as mentioned above, and most preferably, all the various substituents are compounds which are prefe ⁇ ed groups as mentioned above.
  • Specific examples ofthe azo dye represented by the general formula (1-4) will be given below, but the azo dye to be used in the present invention is not limited to the following examples. In the following specific examples, the carboxyl group, phosphono group and sulfo group may be used in the form of salt.
  • Examples of the counter ion forming the salt include ammonium ion, alkaline metal ion (e.g., lithium ion, sodium ion, potassium ion), and organic cation (e.g., tetramethylammomum ion, tetramethylguanidium ion, tetramethylphosphonium ion). Prefe ⁇ ed among these counter ions is lithium ion.
  • the azo dyes represented by the aforementioned general formulae (1-4), (4-A), (4-B) and (4-D) can be synthesized by the coupling reaction of diazo component with coupler.
  • a main synthesis method there may be used one disclosed in Japanese Patent Application No. 2002-113460.
  • a dyes (S) having ⁇ max of from 350 nm to 500 nm there is preferably used a yellow dye or yellow pigment described below.
  • the content ofthe azo dye represented by the general formula (1 ⁇ 4) in the ink is preferably from 0.2% to 20% by weight, more preferably from 0.5% to 15% by weight.
  • the ink ofthe invention may comprise other dyes in combination with the dyes ofthe present invention.
  • Examples of these dyes which can be used in combination with the dyes ofthe present invention include the following dyes.
  • Examples of yellow dyes include aryl or heterylazo dyes having phenols, naphthols, anilines, pyrazolones, pyridones or closed-chain type active methylene compounds as coupling components, azomethine dyes having closed-chain type active methylene compounds as coupling components, methine dyes such as benzylidene dyes and monomethine oxonol dyes, and quinone-based dyes such as naphthoquinone dye and anthraquinone dye.
  • yellow dyes include quinophthalone dye, nitro-nitroso dye, acridine dye, and acridinone dye. These dyes may assumes yellow only when chromophore is partly dissociated, and, in this case, the counter cation may be an inorganic cation such as alkaline metal ion and ammonium ion or an organic cation such as pyridinium ion and quaternary ammonium salt ion or may be contained in a polymer cation as a partial structure.
  • the counter cation may be an inorganic cation such as alkaline metal ion and ammonium ion or an organic cation such as pyridinium ion and quaternary ammonium salt ion or may be contained in a polymer cation as a partial structure.
  • magenta dyes examples include aryl or heterylazo dyes having phenols, naphthols or anilines as coupling components, azomethine dyes having pyrazolones or pyrazolotriazoles as coupling components, methine dyestuffs such as arylidene dye, styryl dye, melocyanine dye and oxonol dye, carbonium dye such as diphenylmethane dye, triphenylmethane dye and xanthene dye, quinone-based dye such as naphthoquinone, anthraquinone and anthrapyridone, and condensed polycyclic dye such as dioxazine dye.
  • methine dyestuffs such as arylidene dye, styryl dye, melocyanine dye and oxonol dye
  • carbonium dye such as diphenylmethane dye, triphenylmethane dye and xanthene dye
  • the counter cation may be an inorganic cation such as alkaline metal ion and ammonium ion or an organic cation such as pyridinium ion and quaternary ammonium salt ion or may be contained in a polymer cation as a partial structure.
  • cyan dyes examples include azomethine dyes such as indoaniline dye and indophenol dye, polymethine dyes such as cyanine dye, oxonol dye and melocyanine dye, carbonium dyes such as diphenylmethane dye, triphenylmethane dye and xanthene dye, phthalocyanine dyes, anthraquinone dyes, aryl or heterylazo dyes having phenols, naphthols or anilines as coupling components, and indigo-thioindigo dyes.
  • azomethine dyes such as indoaniline dye and indophenol dye
  • polymethine dyes such as cyanine dye, oxonol dye and melocyanine dye
  • carbonium dyes such as diphenylmethane dye, triphenylmethane dye and xanthene dye
  • phthalocyanine dyes anthraquinone dyes
  • these dyes may assume cyan only when chromophore is partly dissociated, and, in this case, the counter cation may be an inorganic cation such as alkaline metal ion and ammonium ion or an organic cation such as pyridinium ion and quaternary ammonium salt ion or may be contained in a polymer cation as a partial structure. Alternatively, a black dyestuff such as polyazo dye may be used.
  • Other examples of dyes employable herein include water-soluble dyes such as direct dye, acidic dye, food dye, basic dye and reactive dye. Prefe ⁇ ed examples of these water-soluble dyes include: C.I.
  • the ink composition ofthe invention may comprise pigments incorporated therein as well.
  • pigments to be used in the present invention there may be used commercially available products as well as known compounds listed in various literatures. Examples of these literatures include Color Index (compiled by The Society of Dyers and Colourists), "Kaitei Shiriban Ganryo Binran (Revised Edition of Handbook of Pigments)", compiled by Japan Association of Pigment Technology, 1989, “Saishin Ganryo Ouyou Gijutsu (Modern Applied Technology of Pigments)", CMC, 1986, “Insatsu Inki Gijutsu (Printing Ink Technology)", CMC, 1984, and W. Herbst, K.
  • pigments include organic pigments such as azo pigment (e.g., azo lake pigment, insoluble azo pigment, condensed azo pigment, chelate azo pigment), polycyclic pigment (e.g., phthalocyanine pigment, anthraquinone-based pigment, peiylene-based pigment, perynone-based pigment, indigo-based pigment, quinacridone-based pigment, dioxazine-based pigment, isoindolinone-based pigment, quinophthalone-based pigment, diketopypy ⁇ olopy ⁇ ole-based pigment), dyed lake pigment (e.g., acidic or basic dye lake pigment) and azine pigment, and inorganic pigments such as yellow pigment (e.g., C.I.
  • azo pigment e.g., azo lake pigment, insoluble azo pigment, condensed azo pigment, chelate azo pigment
  • polycyclic pigment e.g., phthalocyanine pigment, anthraquinone-
  • Pigment Yellow 34, 37, 42, 53 red pigment (e.g., C.I. Pigment Red 101, 108), blue pigment (e.g., C.I. Pigment blue 27, 29, 17 : 1), black pigment (e.g., C.I. Pigment Black 7, magnetite) and white pigment (e.g., CL Pigment White 4, 6, 18, 21).
  • red pigment e.g., C.I. Pigment Red 101, 108
  • blue pigment e.g., C.I. Pigment blue 27, 29, 17 : 1
  • black pigment e.g., C.I. Pigment Black 7, magnetite
  • white pigment e.g., CL Pigment White 4, 6, 18, 21.
  • a blue or cyan pigment such as phthalocyanine pigment, anthraquinone-based mdanthrone pigment (e.g., CL Pigment Blue 60) and dyed lake pigment-based triarylcarbonium pigment, particularly phthalocyanine pigment (Prefe ⁇ ed examples ofthe phthalocyanine pigment include copper phthalocyanine such as CL Pigment Blue 15: 1, 15:2, 15:3, 15:4 and 15:6, monochlorophthalocyanine, low cl orination copper phthalocyanine, aluminum phthalocyanine such as pigment listed in European Patent 860475, metal-free phthalocyanine such as CL Pigment Blue 16, and phthalocyanine having Zn, Ni or Ti as a central metal.
  • phthalocyanine pigment e.g., anthraquinone-based mdanthrone pigment (e.g., CL Pigment Blue 60) and dyed lake pigment-based triarylcarbonium pigment, particularly phthalocyanine pigment
  • Particularly prefe ⁇ ed among these phthalocyanine dyes are CL Pigment Blue 15:3, 15:4, and aluminum phthalocyanine).
  • Prefe ⁇ ed examples of red or purple pigments include azo pigments (Prefe ⁇ ed examples of these dyes include CL Pigment Red 3, 5, 11, 22, 38, 48:1, 48:2, 48:3, 48:4, 49:1, 52:1, 53:1, 57:1, 63:2, 144, 146, 184.
  • Particularly prefe ⁇ ed among these dyes are CL Pigment Red 57: 1, 146, 184), quinacridone-based pigments (Prefe ⁇ ed examples of these dyes include CL Pigment Red 122, 192, 202, 207, 209, and CL Pigment Violet 19, 42.
  • Particularly prefe ⁇ ed among these dyes is C.I. Pigment Red 122), dyed lake-based triarylcarbonium pigments (Prefe ⁇ ed examples of these dyes include xanfhene-based CL Pigment Red 81:1, CL Pigment Violet 1, 2, 3, 27, 39), dioxazine-based pigments (e.g., CL Pigment Violet 23, 37), diketopyrrolopy ⁇ ole-based pigments (e.g., CL Pigment Red 254), perylene pigments (e.g., CL Pigment Violet 29), anthraquinone-based pigments (e.g., CL Pigment Violet 5:1, 31, 33), and thioindigo-based pigments (e.g., CL Pigment Red 38, 88).
  • xanfhene-based CL Pigment Red 81:1, CL Pigment Violet 1, 2, 3, 27, 39 dioxazine-based pigments
  • dioxazine-based pigments e.g., CL Pigment Violet
  • Prefe ⁇ ed examples of yellow pigments include azo pigments (Prefe ⁇ ed examples of these dyes include monoazo pigment-based dyes such as CL Pigment Yellow 1, 3, 74, 98, disazo pigment-based dyes such as CL Pigment Yellow 12, 13, 14, 16, 17, 83, general azo-based dyes such as C.I. Pigment Yellow 93, 94, 95, 128, 155 and benzimidazolone-based dyes such as CL Pigment Yellow 120, 151, 154, 156, 180.
  • monoazo pigment-based dyes such as CL Pigment Yellow 1, 3, 74, 98
  • disazo pigment-based dyes such as CL Pigment Yellow 12, 13, 14, 16, 17, 83
  • general azo-based dyes such as C.I. Pigment Yellow 93, 94, 95, 128, 155
  • benzimidazolone-based dyes such as CL Pigment Yellow 120, 151, 154, 156, 180.
  • Particularly prefe ⁇ ed among these dyes are those prepared from materials other than benzidine-based compounds), isoindoline- isoindolinone-based pigments (Prefe ⁇ ed examples of these dyes include CL Pigment Yellow 109, 110, 137, 139), quinophthalone pigments (Prefe ⁇ ed examples of these dyes include C.I. Pigment Yellow 138), and flavanthrone pigment (e.g., CL Pigment Yellow 24).
  • Prefe ⁇ ed examples of black pigments include inorganic pigments (Prefe ⁇ ed examples of these pigments include carbon black, and magnetite), and aniline black. Besides these pigments, orange pigments(C.I.
  • Pigment Orange 13, 16 may be used.
  • the pigments which may be used in the present technique may be untreated pigments as mentioned above or may be surface-treated pigments.
  • surface treatment methods there may be proposed a method involving surface coat with a resin or wax, a method involving the attachment of a surface activator, a method involving the bonding of a reactive material (e.g., silane coupling agent, radical produced from an epoxy compound, polyisocyanate or diazonium salt) to the surface of pigment, etc., and these methods are described in the following literatures and patents.
  • silane coupling agent e.g., silane coupling agent, radical produced from an epoxy compound, polyisocyanate or diazonium salt
  • the pigment may be further dispersed with a dispersant.
  • a dispersant there may be used any of known compounds depending on the pigment used, e.g., surface active agent type low molecular dispersant or polymer type dispersant. Examples of these dispersants include those disclosed in JP-A-3 -69949 and European Patent 549,486.
  • a pigment derivative called synergist may be added.
  • the particle diameter ofthe pigment which may be used in the present invention is preferably from 0.01 ⁇ m to 10 ⁇ m, more preferably from 0.05 ⁇ m to 1 ⁇ m.
  • the dispersing machine As a method for dispersing the pigment there may be used a known dispersion technique for use in the production of ink or toner.
  • the dispersing machine include vertical or horizontal agitator mill, attritor, colloid mill, ball mill, three-roll mill, pearl mill, super mill, impeller, disperser, KD mill, dynatron, and pressure kneader. The details of these dispersing machines are described in "Saishin Ganryo Ouyou Gijutsu (Modern Applied Technology of Pigments)", CMC, 1986.
  • the surface active agent to be incorporated in a recording ink preferably, an ink for inkjet recording composition ofthe present invention will be described hereinafter.
  • the surface active agent By adding the surface active agent to the recording ink (preferably, an ink for inkjet recording) composition and adjusting the physical properties such as surface tension ofthe ink, the ejection stability ofthe ink can be enhanced, exerting an excellent effect of enhancing the water resistance of image and preventing bleeding of ink printed.
  • Examples ofthe aforementioned surface active agents include anionic surface active agents such as sodium dodecylsulfate, sodium dodecyloxysulfonate and sodium alkylbenzenesulfonate, cationic surface active agents such as cetyl pyridinium chloride, trimethylcetyl ammonium chloride and tetrabutylammonium chloride, and nonionic surface active agents such as polyoxyethylenenonly phenyl ether, polyoxyethylene naphthyl ether and polyoxyethyleneoctylphenyl ether. Prefe ⁇ ed among tliese surface active agents are nonionic surface active agents.
  • the content of he surface active agent is from 0.001 to 20% by weight, preferably from 0.005 to 10% by weight, more preferably from 0.01 to 5% by weight based on the weight ofthe ink.
  • a recording method comprising ejecting ink drops by using at least two color inks of yellow and magenta each comprising a dye onto a recording material, the recording material comprising a support and an ink-receptive layer provided on the support, according to a recording signal, so as to record an image on the recording material, wherein the percent bleeding ofthe recorded image is 30% or less.
  • the yellow dye will be first described.
  • the yellow dye to be used in the invention preferably has an oxidation potential of more positive than 1.0 V (vs SCE), more preferably more positive than 1.1 V (vs SCE), particularly more positive than 1.15 V (vs SCE) from the standpoint of fastness, particularly to ozone gas.
  • vs SCE 1.0 V
  • vs SCE 1.1 V
  • vs SCE 1.1 V
  • vs SCE 1.1 V
  • the oxidation potential (Eox) can be easily measured by those skilled in the art. For the details of the method for measuring the oxidation potential, reference can be made to P. Delahay, "New Instrumental Methods in Electrochemistry", 1954, Interscience Publishers, A. J.
  • the measurement of oxidation potential is carried Out by dissolving the test specimen in a solvent such as dimethylformamide and acetonitrile containing a supporting electrolyte such as sodium perchlorate and tetrapropylammonium perchlorate in a concentration of from 1 x 10 "4 to 1 x 10 "6 mol/1, and then measuring the test solution for oxidation potential with respect to SCE (saturated calomel electrode) using cyclic voltammetry or DC polarography. This value may deviate by scores of millivolts due to the effect of difference in potential between solutions or resistivity of test solution.
  • a solvent such as dimethylformamide and acetonitrile containing a supporting electrolyte such as sodium perchlorate and tetrapropylammonium perchlorate in a concentration of from 1 x 10 "4 to 1 x 10 "6 mol/1
  • oxidation potential of dye the potential measured in dimethylformamide containing 0.1 mol dm "3 of tetrapropylammonium perchlorate as a supporting electrolyte (concentration of dye: 0.001 mol dm 3 ) using DC polarography is defined as oxidation potential of dye.
  • the value of oxidation potential Eox indicates the transferability of electrons from the specimen to the electrode.
  • the incorporation of electron-withdrawing group causes the oxidation potential to be more positive while the incorporation of electron-donative group causes the oxidation potential to be more negative.
  • ozone which is an electrophilic agent
  • an electron-withdrawing group be introduced into the skeleton of yellow dye to make the oxidation potential thereof more positive.
  • the dye to be used in the invention preferably exhibits a good fastness as well as a good hue.
  • the yellow dye to be used in the invention preferably exhibits ⁇ max of from 390 nm to 470 nm and I( ⁇ max + 70 nm)/I( ⁇ max) ratio (ratio of absorbance at ⁇ max + 70 nm (I( ⁇ max + 70 nm)) to absorbance at ⁇ max (I( ⁇ max)) of 0.20 or less, more preferably 0.15 or less, ven more preferably 0.10 or less.
  • the absorption wavelength and absorbance defined herein indicate value measured in a solvent (water or ethyl acetate).
  • a dye satisfying these oxidation potential and absorption characteristics there is preferably used one represented by the following general formula (2-2).
  • (A u -N N-B Colour) n -L ... (2-2) wherein An and Bn each independently represent a heterocyclic group which may be substituted; n represents an integer 1 or 2; and L represents a hydrogen atom, mere bond or divalent connecting group, with the proviso that when n is 1, L represents a hydrogen atom and both A u and B are a monovalent heterocyclic group and when n is 2, L represents a mere bond or divalent connecting group, one of A ⁇ and Bn is a monovalent heterocyclic group and the other is a divalent connecting group, and two n's and Bn's each may be the same or different.
  • the heterocyclic group is preferably a heterocyclic group formed by a 5-membered or 6-membered ring.
  • the heterocyclic group may have a monocyclic structure or a polycyclic structure formed by the condensation of two or more rings or may be an aromatic heterocyclic group or non-aromatic heterocyclic group.
  • hetero atoms constituting the aforementioned heterocyclic group there are preferably used nitrogen, oxygen and sulfur atoms.
  • the suffix n is more preferably 2.
  • L is a hydrogen atom, L can be connected to A ⁇ or B n at arbitrary position.
  • the magenta ink to be incorporated in the recording ink ofthe invention comprises a magenta dye selected from azo dyes dissolved or dispersed in an aqueous medium.
  • the magenta dye to be used herein is basically characterized in that it is a dye having a maximal absorption at a wavelength of from 500 nm to 580 nm in the aqueous medium and an oxidation potential of more positive than 1.0 V (vs SCE).
  • the heterocyclic ring A and the heterocyclic ring B in the aforementioned general formula may have the same structure.
  • the heterocyclic ring A and heterocyclic ring B each are in detail a 5- or 6-membered heterocyclic ring which is selected from pyrazole, imidazole, triazole, oxazole, thiazole, selenazole, pyridone, pyrazine, pyrimidine and pyridine. In some detail, they are described in JP-A-2001-279145, JP-A-2002-309116, JP-A- 2003-12650, etc.
  • the second prefe ⁇ ed structural characteristic ofthe aforesaid azo dye is that the azo group is an azo dye having an aromatic mtrogen-containing 6-membered heterocyclic ring directly connected to at least one end thereof as a coupling component, and specific examples of such an azo dye are described in JP-A-2002- 371214.
  • the third prefe ⁇ ed structural characteristic is that the chromophore has an aromatic cyclic amino group or heterocyclic amino group structure, and specific examples ofthe chromophore include anilino group, and heterylamino group.
  • the fourth prefe ⁇ ed structural characteristic is that the azo dye has a stereostructure. This is described in detail in JP-A-2002-371214.
  • a 31 represents a 5-membered heterocyclic ring.
  • hetero atoms in the heterocyclic ring include N, O and S.
  • the 5-membered heterocyclic ring is preferably a nitrogen- containing 5-membered heterocyclic ring which may be condensed with aliphatic rings, aromatic rings or other heterocyclic rings.
  • heterocyclic group examples include pyrazole ring, imidazole ring, thiazole ring, isothiazole ring, thiadiazole ring, benzothiazole ring, benzooxazole ring, and benzoisothiazole ring.
  • the various heterocyclic groups may further have substituents. Prefe ⁇ ed among these heterocyclic rings are pyrazole ring, imidazole ring, isothiazole ring, thiadiazole ring and benzothiazole ring represented by the following general formulae (a) tc ) (f ) : (a) (b)
  • R 7 to R 22 represent the same substituents as G, R 1 and R 2 in the general formula (MI).
  • Prefe ⁇ ed among the compounds ofthe general formulae (a) to (g) are pyrazole ring represented by the general formula (a) and isothiazole ring represented by the general formula (b), most preferably pyrazole ring represented by the general formula (a).
  • R 5 and R 6 each independently represent a hydrogen atom or substituent.
  • the substituent represents an aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group or sulfamoyl group.
  • the hydrogen atom of these substituents may be substituted.
  • Prefe ⁇ ed examples of R 5 and R 6 may include hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, alkylsulfonyl group, and arylsulfonyl group.
  • R 5 and R 6 each are a hydrogen atom, aromatic group, heterocyclic group, acyl group, alkylsulfonyl group or arylsulfonyl group. Most preferably, R 5 and R 6 each are a hydrogen atom, aryl group or heterocyclic group. The hydrogen atom of the aforementioned various substituents may be substituted. However, R 5 and R 6 are not a hydrogen atom at the same time.
  • G 31 , R 1 and R 2 each independently represent a hydrogen atom or substituent.
  • the substituent represents a halogen atom or an aliphatic group, aromatic group, heterocyclic group,' cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, acyl group, hydroxyl group, alkoxy group, aryloxy group, heterocyclic oxy group, silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxy carbonyloxy group, amino group (including alkylamino group, arylamino group and heterocyclic amino group), acylamino group, ureido group, sulfamonylamino group, alkoxycarbonyl amino group, aryloxycarbonylamino group, alkyl sulfonylamino group, arylsulfonylamino group, heterocyclic sulfonylamino group, nitro group, al
  • G 31 is preferably a hydrogen atom, halogen atom, aliphatic group, aromatic group, hydroxy group, alkoxy group, aryloxy group, acyloxy group, heterocyclic oxy group, amino group (including alkylamino group, arylamino group, and heterocyclic amino group), acylamino group, ureido group, sulfamoylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkylthio group, arylthio group or heterocyclic thio group, more preferably a hydrogen atom, halogen atom, alkyl group, hydroxy group, alkoxy group, aryloxy group, acyloxy group, amino group or acylamino group, most preferably a hydrogen atom, amino group (preferably anilino group) or acylamino group.
  • the hydrogen atom ofthe aforesaid substituents may be substituted.
  • R 1 and R 2 include hydrogen atom, alkyl group, halogen atom, alkoxycarbonyl group, carboxyl group, carbamoyl group, hydroxy group, alkoxy group, and cyano group.
  • the hydrogen atom ofthe aforesaid substituents may be substituted.
  • R 1 and R 5 or R 5 and R s may be connected to each other to form a 5- or 6-membered ring. Examples ofthe substituents which may substitute on A 31 or which may substitute on the substituents of R 1 , R 2 , R 5 , R 6 or G include those listed above with reference to G 31 , R 1 and R 2 .
  • an ionic hydrophilic group is further provided on any position on A 31 , R 1 , R 2 , R 5 , R 6 and G 31 as a substituent.
  • the ionic hydrophilic group as a substituent include sulfo group, carboxyl group, phosphono group, quaternary ammonium group, etc.
  • the aforesaid ionic hydrophilic group is preferably a carboxyl group, phosphono group or sulfo group, particularly carboxyl group or sulfo group.
  • the carboxyl group, phosphono group and sulfo group may be in the form of salt.
  • counter ions constituting the salt examples include ammonium ion, alkaline metal ion (e.g., lithium ion, sodium ion, potassium ion), and organic cation (e.g., tetramethylammonium ion, tetrametliylguanidium ion, tetramethyl phosphonium).
  • alkaline metal ion e.g., lithium ion, sodium ion, potassium ion
  • organic cation e.g., tetramethylammonium ion, tetrametliylguanidium ion, tetramethyl phosphonium.
  • the terms (substituent) as used herein will be described. These terms are common to the general formula (MI) and the general formula (Mia) described later even the signs are different.
  • the halogen atom include fluorine atom, chlorine atom, and bromine atom.
  • the aliphatic group means alkyl group, substituted alkyl group, alkenyl group, substituted alkenyl group, alkinyl group, substituted alkinyl group, aralkyl group and substituted aralkyl group.
  • substituted as used in "substituted alkyl group", etc. means that the hydrogen atom in "alkyl group", etc. is substituted by substituents listed above with reference to G 31 , R 1 and R 2 , etc.
  • the aliphatic group may have branches or may form a ring.
  • the number of carbon atoms in the aliphatic group is preferably from 1 to 20, more preferably from 1 to 16.
  • the aryl moiety ofthe aralkyl group or substituted aralkyl group is preferably a phenyl group or naphthyl group, particularly phenyl group.
  • the aliphatic group include methyl group, ethyl group, butyl group, isopropyl group, t-butyl group, hydroxyethyl group, methoxyethyl group, cyanoethyl group, trifluoromethyl group, 3-sulfopropyl group, 4- sulfobutyl group, cyclohexyl group, benzyl group, 2-phenethyl group, vinyl group, and allyl group.
  • the aromatic group means an aryl group or substituted aryl group.
  • the aryl group is preferably a phenyl group or naphthyl group, particularly phenyl group.
  • the number of carbon atoms in the aromatic group is preferably from 6 to 20, more preferably from 6 to 16.
  • the aromatic group include phenyl group, p-tollyl group, p-methoxyphenyl group, o- chlorophenyl group, and m-(3-sulfopropylamino)phenyl group.
  • the heterocyclic group include substituted heterocyclic groups.
  • the heterocyclic group may have its heterocyclic ring condensed with aliphatic rings, aromatic rings or other heterocyclic rings.
  • the aforesaid heterocyclic group is preferably a 5- or 6-membered heterocyclic ring.
  • substituents include aliphatic group, halogen atom, alkylsulfonyl group, arylsulfonyl group, acyl group, acylamino group, sulfamoyl group, carbamoyl group, ionic hydrophilic group, etc.
  • heterocyclic group include 2-pyridyl group, 2-thienyl group, 2-thiazolyl group, 2-benzothiazolyl group, 2- benzooxazolyl group, and 2-furyl group.
  • Examples ofthe carbamoyl group include substituted carbamoyl groups.
  • Examples ofthe aforesaid substituents include alkyl group.
  • Examples ofthe aforesaid carbamoyl group include methylcarbamoyl group, and dimethylcarbamoyl group.
  • Examples ofthe alkoxycarbonyl group include substituted alkoxycarbonyl groups.
  • the aforesaid alkoxycarbonyl group is preferably an alkoxycarbonyl group having from 2 to 20 carbon atoms.
  • Examples of the aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkoxycarbonyl group include methoxycarbonyl group, and ethoxycarbonyl group.
  • Examples ofthe aryloxycarbonyl group include substituted aryloxycarbonyl groups.
  • the aforesaid aryloxycarbonyl group is preferably an aryloxycarbonyl group having from 7 to 20 carbon atoms.
  • Examples of the aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid aryloxycarbonyl group include phenoxycarbonyl group.
  • Examples ofthe heterocyclic oxycarbonyl group include substituted heterocyclic oxycarbonyl groups. Examples ofthe heterocyclic ring include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic oxycarbonyl group is preferably a heterocyclic oxycarbonyl group having from 2 to 20 carbon atoms.
  • the aforesaid substituents include ionic hydrophilic groups.
  • the aforesaid heterocyclic oxycarbonyl group include 2-pyridyloxycarbonyl group.
  • the acyl group include substituted acyl groups.
  • the aforesaid acyl group is preferably an acyl group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • the aforesaid acyl group include acetyl group and benzoyl group.
  • Examples ofthe alkoxy group include substituted alkoxy groups.
  • Examples ofthe aforesaid alkoxy group is preferably an alkoxy group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkoxy groups, hydroxyl groups, and ionic hydrophilic groups.
  • Examples ofthe aforesaid alkoxy group include methoxy group, ethoxy group, isopropoxy group, methoxyethoxy group, hydroxyethoxy group, and 3- carboxypropoxy group.
  • Examples ofthe aryloxy group include substituted aryloxy groups.
  • the aforesaid aryloxy group is preferably an aryloxy group having from 6 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkoxy groups, and ionic hydrophilic groups.
  • Examples ofthe aforesaid aryloxy group include phenoxy group, p-methoxyphenoxy group, and o-methoxyphenoxy group.
  • Examples ofthe heterocyclic oxy group include substituted heterocyclic oxy groups. Examples ofthe heterocyclic ring include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic oxy group is preferably a heterocyclic oxy group having from 2 to 20 carbon atoms. Examples ofthe aforesaid substituents include alkyl groups, alkoxy group, and ionic hydropl ⁇ lic groups.
  • Examples ofthe aforesaid heterocyclic oxy group include 3-pyridyloxy group, and 3-thienyloxy group.
  • the silyloxy group is preferably a silyloxy group substituted by an aliphatic or aromatic group having from 1 to 20 carbon atoms. Examples ofthe aforesaid silyloxy group include trimethylsilyloxy, and diphenylmethyl silyloxy. Examples ofthe acyloxy group include substituted acyloxy groups.
  • the aforesaid acyloxy group is preferably an acyloxy group having from 1 to 20 carbon atoms. Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid acyloxy group include acetoxy group, and benzoyloxy group.
  • the carbamoyloxy group include substituted carbamoyloxy groups.
  • Examples ofthe aforesaid substituents include alkyl groups.
  • Examples ofthe aforesaid carbamoyloxy group include N- methylcarbamoyloxy group.
  • Examples of the alkoxycarbonyloxy group include substituted alkoxycarbonyloxy groups.
  • the aforesaid alkoxycarbonyloxy group is preferably an alkoxycarbonyl oxy group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid alkoxycarbonyloxy group include methoxy carbonyloxy group, and isopropoxycarbonyloxy group.
  • Examples of the aryloxycarbonyloxy group include substituted aryloxycarbonyloxy groups.
  • the aforesaid aryloxycarbonyloxy group is preferably an aryloxy carbonyloxy group having from 7 to 20 carbon atoms.
  • Examples ofthe aforesaid aryloxycarbonyloxy group include phenoxycarbonyloxy group.
  • Examples ofthe amino group include substituted amino groups.
  • Examples ofthe aforesaid substituents include alkyl groups, aryl groups, and heterocylic groups, and the alkyl groups, aryl groups and heterocyclic groups may further have substituents.
  • Examples ofthe alkylamino group include substituted alkylamino groups.
  • the alkylamino group is preferably an alkylamino group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkylamino group include methylamino group, and diethylamino group.
  • Examples ofthe arylamino group include substituted arylamino groups.
  • the aforesaid arylamino group is preferably an arylamino group having from 6 to 20 carbon atoms.
  • the aforesaid substituents include halogen atoms, and ionic hydrophilic groups.
  • Examples ofthe aforesaid arylamino group include phenylamino group, and 2-chlorophenylamino group.
  • Examples ofthe heterocyclic amino group include substituted heterocyclic amino groups. Examples of the heterocyclic ring include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic amino group is preferably a heterocyclic amino group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkyl groups, halogen atoms, and ionic hydrophilic groups.
  • Examples ofthe acylamino group include substituted acrylamino groups.
  • the aforesaid acylamino group is preferably an acylamino group having from 2 to 20 carbon atoms.
  • Examples of the aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid acylamino group include acetylamino group, propionylamino group, beiizoylam ⁇ no group, N-phenyl acetylamino group, and 3,5-disulfobenzoylamino group.
  • Examples ofthe ureido group include substituted ureido groups.
  • the aforesaid ureido group is preferably an ureido group having from 1 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include alkyl groups, and aryl groups.
  • Examples ofthe aforesaid ureido group include 3-methylureido group, 3,3- dimethyl ureido group, and 3-phenylureido group.
  • Examples ofthe sulfamoylamino group include substituted sulfamoylamino groups.
  • Examples ofthe aforesaid substituents include alkyl groups.
  • Examples ofthe aforesaid sulfamoylamino group include N,N- dipropylsulfamoylamino group.
  • Examples ofthe alkoxycarbonylamino group include substituted alkoxycarbonylamino groups.
  • the aforesaid alkoxycarbonylamino group is preferably an alkoxy carbonylamino group having from 2 to 20 carbon atoms.
  • Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkoxycarbonylamino group include ethoxycarbonylamino groups.
  • Examples ofthe aryloxycarbonylamino group include substituted aryloxycarbonylamino groups.
  • the aforesaid aryloxycarbonylamino group is preferably an aryloxycarbonylamino group having from 7 to 20 carbon atoms.
  • substituents include ionic hydrophilic groups.
  • aryloxycarbonylamino group include phenoxycarbonyl amino groups.
  • alkylsulfonylamino group and arylsulfonylamino group include substituted alkyl sulfonylamino groups and substituted arylsulfonylamino groups.
  • the aforesaid altylsulfonylamino group and arylsulfonylamino group are preferably an alkylsulfonyl amino group having from 1 to 20 atoms and arylsulfonylamino group having from 7 to 20 carbon atoms.
  • the substituents include ionic hydrophilic groups.
  • the aforesaid alkylsulfonylamino group and arylsulfonyl amino group include methylsulfonylamino group, N-phenyl-methyl sulfonylamino group, phenylsulfonyl amino group, and 3- carboxyphenylsulfonyl amino group.
  • heterocyclic sulfonylamino group examples include substituted sulfonylamino groups.
  • the heterocyclic ring examples include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic sulfonylamino group is preferably a heterocyclic sulfonylamino group having from 1 to 12 carbon atoms.
  • the aforesaid substituents include ionic hydrophilic groups.
  • examples ofthe aforesaid heterocyclic sulfonylamino group include 2-tl ⁇ enylsulfonylamino group, and 3-pyridylsulfonyl amino group.
  • alkylthio group, arylthio group and heterocyclic thio group examples include substituted alkylthio group, substituted arylthio group, and substituted heterocyclic thio group.
  • heterocyclic ring examples include those listed above with reference to the heterocyclic group.
  • the aforesaid alkylthio group, arylthio group and heterocyclic thio group each preferably have from 1 to 20 carbon atoms.
  • substituents include ionic hydrophilic groups.
  • Examples ofthe aforesaid alkylthio group, arylthio group and heterocyclic thio group include methylthio group, phenylthio group, and 2-pyridylthio group.
  • Examples ofthe alkylsulfonyl group and aryl sulfonyl group include substituted alkylsulfonyl groups and substituted arylsulfonyl groups.
  • Examples ofthe alkylsulfonyl group and arylsulfonyl group include methylsulfonyl group and phenylsulfonyl group, respectively.
  • Examples ofthe heterocyclic sulfonyl group include substituted heterocyclic sulfonyl groups.
  • heterocyclic ring examples include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic sulfonyl group is preferably a heterocyclic sulfonyl group having from 1 to 20 carbon atoms.
  • substituents include ionic hydrophilic groups.
  • examples ofthe aforesaid heterocyclic sulfonyl group include 2-thienylsulfonyl group and 3-pyridylsulfonyl group.
  • alkylsulfinyl group and arylsulfinyl group include substituted alkylsulfinyl groups and substituted arylsulfinyl groups.
  • Examples ofthe alkylsulfinyl group and arylsulfinyl group include methylsulfinyl group and phenylsulfinyl group, respectively.
  • Examples ofthe heterocyclic sulfinyl group include substituted heterocyclic sulfinyl groups.
  • Examples ofthe heterocyclic ring include those listed above with reference to the heterocyclic group.
  • the aforesaid heterocyclic sulfinyl group is preferably a heterocyclic sulfinyl group having from 1 to 20 carbon atoms. Examples ofthe aforesaid substituents include ionic hydrophilic groups.
  • heterocyclic sulfinyl group examples include 4-pyridylsulfinyl group.
  • the sulfamoyl group include substituted sulfamoyl groups.
  • the aforesaid substituents include alkyl groups.
  • the aforesaid sulfamoyl group include dimethylsulfamoyl group, and di-(2-hydroxyethyl)sulfamoyl group.
  • Particularly prefe ⁇ ed among the structures ofthe general formula (MI) is one represented by the following general formula (Mia), general formula (Mia):
  • R 1 , R 2 , R 5 and R 6 are as defined in the general formula (Ml).
  • R 3 and R 4 each independently represent a hydrogen atom or a substituent which represents an aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group or sulfamoyl group.
  • Z 1 represents an electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.20 or more.
  • Z 1 is preferably an electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.30 or more, more preferably 0.45 or more, particularly 0.60 or more, but the Hammett's substituent constant ⁇ p ofthe electron-withdrawing group is preferably not greater than 1.0.
  • Specific prefe ⁇ ed examples of the substituents include electron-withdrawing substituents described later.
  • Prefe ⁇ ed among these electron-witlidrawing substituents are C 2 -C 2 o acyl group, C 2 -C 2 o alkyloxycarbonyl group, nitro group, cyano group, -C 20 alkylsulfonyl group, C 6 -C 2 o arylsulfonyl group, C 1 -C 20 carbamoyl group, and C ⁇ -C 20 halogenated alkyl group.
  • Particularly prefe ⁇ ed among these electron-withdrawing substituents are cyano group, C ⁇ -C 20 alkylsulfonyl group, and C 6 -C 2 o arylsulfonyl group.
  • Z 2 represents a hydrogen atom or a substituent and the substituent represents an aliphatic group, aromatic group or heterocyclic group.
  • Z 2 is preferably an aliphatic group, more preferably a Ci-C ⁇ alkyl group.
  • Q represents a hydrogen atom or a substituent and the substituent represents an aliphatic group, aromatic group or heterocyclic group.
  • Q is preferably a group formed by a group of non-metallic atoms required to form a 5- to 8-membered ring.
  • the aforementioned 5- to 8-membered ring may be substituted, may be a saturated ring or may have an unsaturated bond.
  • Particularly prefe ⁇ ed among these 5- to 8-membered rings are aromatic group and heterocyclic group.
  • Prefe ⁇ ed examples ofthe non-metallic atom include nitrogen atom, oxygen atom, sulfur atom, and carbon atom.
  • Specific examples of these cyclic structures include benzene ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, cyclohexene ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, imidazole ring, benzoimidazole ring, oxazole ring, benzoxazole ring, thiazole ring, benzothiazole ring, oxane ring, sulfolane ring, and thiane ring.
  • the hydrogen atoms in the substituents described with reference to the general formula (Mia) maybe substituted.
  • substituents on these substituents include substituents listed with reference to the general formula (MI), and groups and ionic hydrophilic groups exemplified with reference to G 31 , R 1 and R 2 .
  • the Hammett's substituent constant ⁇ p will be described hereinafter.
  • Hammett's rule is an empirical rule which L. P. Hammett proposed in 1935 to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives, and the validity of this empirical rule has been widely accepted today.
  • these substituents are defined or described by Hammett's substituent constant ⁇ p, but this does not mean that the known values found in the aforementioned literatures are not limited to certain substituents and it goes without saying that even if the values are unknown in literatures, they contain substituents which may fall within the defined range when measured according to Hammett's rule.
  • the compounds ofthe present invention contain those o the general formula (la) which are not benzene derivatives, and as a measure for indicating the electron effect of substituents there is used ⁇ p value regardless of substitution position. In the present invention, ⁇ p value is used in this sense.
  • the election-withdrawing group having a Hammett's substituent constant ⁇ p of 0.60 or more include cyano group, nitro group, alkylsulfonyl group (e.g., methylsulfonyl group), and arylsulfonyl group (e.g., phenylsulfonyl group).
  • Examples ofthe electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.45 or more include acyl group (e.g., acetyl group), alkoxycarbonyl group (e.g., dodecyloxycarbonyl group), aryloxycarbonyl group (e.g., m-chlorophenoxycarbonyl), alkylsulfinyl group (e.g., n-propylsulfinyl), arylsulfinyl group (e.g., phenylsulfinyl), sulfamoyl group (e.g., N-ethyl sulfamoyl, N,N-m ⁇ ethylsulfamoyl), and halogenated alkyl group (e.g., trifluoromethyl) besides the aforesaid groups.
  • acyl group e.g., acetyl group
  • Examples ofthe electron-withdrawing group having a Hammett's substituent constant ⁇ p of 0.30 or more include acyloxy group (e.g., acetoxy group), carbamoyl group (e.g., N-ethylcarbamoyl, N,N- dibutylcarbamoyl), halogenated alkoxy group (e.g., trifluoromethyloxy), halogenated aryloxy group (e.g., pentafluorophenyloxy), sulfonyloxy group (e.g., methylsulfonyloxy), halogenated alkylthio group (e.g., difiuoromethylthio), aryl group substituted by two or more electron-withdrawing groups having ⁇ p of 0.15 or more (e.g., 2,4-dinitrophenyl, pentachlorophenyl), and heterocyclic group (e.g., 2-benzooxazolyl
  • R 5 and R 6 each are preferably a hydrogen atom, alkyl group, aryl group, heterocyclic group, sulfonyl group or acyl group, more preferably hydrogen atom, aryl group, heterocyclic group or sulfonyl group, most preferably hydrogen atom, aryl group or heterocyclic group.
  • R 5 and R 6 are not a hydrogen atom at the same time.
  • G is preferably a hydrogen atom, halogen atom, alkyl group, hydroxyl group, amino group or acylamino group, more preferably hydrogen atom, halogen atom, amino group or acylamino group, most preferably hydrogen atom, amino group or acylamino group.
  • a 31 is preferably a pyrazole ring, imidazole ring, isothiazole ring, thiadiazole ring or benzothiazole ring, more preferably pyrazole ring or isothiazole ring, most preferably pyrazole ring.
  • At least one ofthe various substituents is preferably a compound which is a prefe ⁇ ed group as mentioned above, and more preferably, more ofthe various substituents are compounds which are prefe ⁇ ed groups as mentioned above, and most preferably, all the various substituents are compounds wliich are prefe ⁇ ed groups as mentioned above.
  • Specific examples o the compound (azo dye) represented by the general formula (Ml) are same as those explained in the general formula (1-3) in the first embodiment.
  • the recording ink (preferably ink for inkjet recording) composition ofthe invention can be prepared by dissolving and/or dispersing at least one ofthe aforementioned azo magenta dyes in an aqueous medium.
  • the recording ink ofthe invention preferably contains an azo dye in an amount of from 0.2 to 20% by weight, more preferably from 0.5 to 15% by weight.
  • the aforementioned azo magenta dye to be used is substantially water-soluble.
  • substantially water-soluble as used herein is meant to indicate that the azo magenta dye is dissolved in 20°C water in an amount of 2% by weight or more.
  • the ink composition for in jet recording ofthe invention may comprise other magenta dyes incorporated therein in combination with the aforementioned azo magenta dye.
  • magenta dyes which can be used in combination with the azo magenta dye include aryl or heterylazo dyes having phenols, naphthols or anilines as coupling components, azomethine dyes having pyrazolones or pyrazolotriazoles as coupling components, methine dyestuffs such as arylidene dye, styryl dye, melocyanine dye and oxonol dye, carbonium dye such as diphenylmethane dye, triphenylmethane dye and xanthene dye, quinone-based dye such as naphthoquinone, anthraquinone and anthrapyridone, and condensed polycyclic dye such as dioxazine dye.
  • the counter cation may be an inorganic cation such as alkaline metal ion and ammonium ion or an organic cation such as pyridinium ion and quaternary ammonium salt ion or may be contained in a polymer cation as a partial structure.
  • the ink composition containing a compound ofthe general formula (MI) ofthe invention further comprises other dyes incorporated therein so far as it can satisfy the ink precipitation test as defined herein.
  • the ink composition ofthe invention is a recording ink (preferably, an ink for inkjet recording) containing, preferably, a water-miscible organic solvent on a betaine-based surface active agent other than dyes.
  • the betaine-based surface active agent to be used in the invention has both cationic and anionic moieties in its molecule and is defined as a compound having surface activity. Examples of the cationic moiety include aminic nitrogen atom, nitrogen atom in heteroaromatic ring, and boron atom having four bonds to carbon. Prefe ⁇ ed among these cationic moieties are aminic nitrogen atom and nitrogen atom in heteroaromatic ring.
  • Particularly prefe ⁇ ed among these cationic moieties is quaternary nitrogen atom.
  • the anionic moiety include hydroxyl group, thio group, sulfonamide group, sulfo group, carboxyl group, imido group, phosphoric acid group, and phosphonic acid group.
  • Particularly prefe ⁇ ed among these anionic moieties are carboxyl group and sulfo group.
  • the charge ofthe entire surface active agent molecule may be cationic, anionic or neutral but is preferably neutral. It is particularly preferred that the betaine-based surface active agent to be used in the invention be a compound represented by the general formula (2-1).
  • R represents a hydrogen atom, alkyl group, aryl group or heterocyclic group.
  • L represents a divalent connecting group.
  • M represents a hydrogen atom, alkaline metal atom, ammonium group, protonated organic amine, protonated nittogen-containing heterocyclic group or quaternary ammonium ion, with the proviso that if it is a counter ion of ammonium ion formed by nitrogen atoms in the molecule represented by the general formula (2-1), it represents a group which does not exist as a cation.
  • the suffix q represents an integer of 1 or more.
  • the suffix r represents an integer of 4 or less.
  • the suffix p represents an integer of from 0 to 4.
  • the sum of p and r is 3 or 4.
  • the plurality of L's may be the same or different.
  • the plurality of COOM groups may be the same or different.
  • r is 2 or more, the plurality of [L-(COOM)q] groups may be the same or different.
  • the plurality of R's may be the same or different.
  • the betaine-based surface active agent to be used in the invention there is preferably used a compound represented by the following general formula (2-6) or (2-7) among those represented by the general formula (2-1).
  • R ⁇ B to R 3B each represent an alkyl group which may be substituted and preferably has from 1 to 20 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, dodecyl group, cetyl group, stearyl group, oleyl group), aryl group which maybe substituted and preferably has from 6 to 20 carbon atoms (e.g., phenyl group, tollyl group, xylyl group, naphthyl group, cumyl group, dodecylphenyl group) or heterocyclic group which may be Substituted and preferably has from 2 to 20 carbon atoms (e.g., pyridyl group, quinolyl group).
  • 1 to 20 carbon atoms e.g., methyl group, ethyl group, propyl group, butyl group, hexyl group, oc
  • R IB to R 3B maybe connected to each other to form a cyclic structure. Particularly prefe ⁇ ed among these groups is alkyl group.
  • L represents a divalent connecting group.
  • Prefe ⁇ ed examples ofthe divalent connecting group include divalent connecting groups containing alkylene group or arylene group as a basic constituent.
  • the connecting main chain may contain hetero atoms such as oxygen atom, sulfur atom and nitrogen atom.
  • R IB to R 3B or L may be substituted by various substituents.
  • substituents include alkyl groups preferably having from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, particularly from 1 to 8 carbon atoms (e.g., methyl, ethyl, iso- propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl), alkenyl groups preferably having from 2 to 20 carbon atoms, more preferably from 2 to 12 carbon atoms, particularly from 2 to 8 carbon atoms (e.g., vinyl, allyl, 2-butenyl, 3-pentenyl), alkinyl groups preferably having from 2 to 20 carbon atoms, more preferably from 2 to 12 carbon atoms, particularly from 2 to 8 carbon atoms (e.g., propargyl, 3- pentinyl), aryl groups preferably having from 6 to 30 carbon atoms
  • substituents may be further substituted. When there are two or more of these substituents, they may be the same or different. If possible, these substituents may be connected to each other to form a ring.
  • a plurality of betaine structures may be contained via Ri to R 3 or L.
  • R ⁇ B to R 3B and L contains a group having 8 or more carbon atoms.
  • R IB to R 3B contain a long-chain alkyl group, general formula (2-7): (R) p] -N-[L-(COOM 1 ) q ] rl wherein R, L and q are as defined in the general formula (1); pi represents an integer of from 0 to 3; rl represents an integer of from 1 to 3; and M 1 represents an alkaline metal cation or hydrogen atom, with the proviso that the sum of pi and rl is 3, when pi is 2 or more, the plurality of R's may be the same or different, and when rl is 2 or more, the plurality of PACOOM 1 ),] groups may be the same or different.
  • R represents a hydrogen atom or an alkyl group which may be substituted and preferably has from 1 to 20 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, dodecyl group, cetyl group, stearyl group, oleyl group), aryl group which may be substituted and preferably has from 6 to 20 carbon atoms (e.g., phenyl group, tollyl group, xylyl group, naphthyl group, cumyl group, dodecylphenyl group) or heterocyclic group which may be substituted and preferably has from 2 to 20 carbon atoms (e.g., pyridyl group, quinolyl group).
  • 1 to 20 carbon atoms e.g., methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl
  • These groups may be connected to each other to form a cyclic structure. Particularly prefe ⁇ ed among these groups is alkyl group.
  • L represents a divalent connecting group.
  • Prefe ⁇ ed examples ofthe divalent connecting group include divalent connecting groups containing alkylene group or arylene group as a basic constituent.
  • the connecting main chain may contain hetero atoms such as oxygen atom, sulfur atom and nitrogen atom.
  • R or L may be substituted by various substituents.
  • substituents include alkyl groups preferably having from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, particularly from 1 to 8 carbon atoms (e.g., methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl), alkenyl groups preferably having from 2 to 20 carbon atoms, more preferably from 2 to 12 carbon atoms, particularly from 2 to 8 carbon atoms (e.g., vinyl, allyl, 2-butenyl, 3-pentenyl), alkinyl groups preferably having from 2 to 20 carbon atoms, more preferably from 2 to 12 carbon atoms, particularly from 2 to 8 carbon atoms (e.g., propargyl, 3-pentinyl), aryl groups preferably having from 6 to 30 carbon atoms
  • substituents may be further substituted. When there are two or more of these substituents, they may be the same or different. If possible, these substituents may be connected to each other to form a ring.
  • a plurality of betaine structures may be contained via R or L.
  • M represents a hydrogen atom, alkaline metal cation (e.g., sodium ion, potassium ion, lithium ion, cesium ion), ammonium ion or aminic organic cation (If it is a primary or tertiary amine, it represents a protonated cation such as protonated methylamine, dimethylamine, ethylamine, diethylamine, triethylamine, diazabicycloundecene, diazabicycloctane, piperidine, pyrrolidine, morpholine, N-methylpiperidine, N- methylmoropholine, pyridine, pyrazine, aniline and N,N-dimetl ⁇ ylaniline.
  • alkaline metal cation e.g., sodium ion, potassium ion, lithium ion, cesium ion
  • ammonium ion or aminic organic cation If it is a primary or tert
  • quaternary ammonium salt it represents, e.g., tetramethylammonium ion, tetraethylammonium ion, trimethylbenzylammonium ion, methylpyridinium ion, benzylpyridinium ion.). Particularly prefe ⁇ ed among these groups are alkaline metal cation and hydrogen atom.
  • the suffix q represents an integer of 1 or more (preferably 5 or less, more preferably 2 or less).
  • the suffix r represents an integer of from 1 to 4 (preferably 1 or 2).
  • the suffix p represents an integer of from 0 to 4 (preferably 1 or 2). The sum of p and r is 3 or 4.
  • the nitrogen atom is a quaternary ammonium cation and one o the plurality of M's is a dissociated anion.
  • the plurality of (COOM) groups may be the same or different.
  • the plurality of [L-(COOM) q ] groups may be the same or different.
  • the plurality of R's may be the same or different.
  • the suffix pi represents an integer of from 0 to 3 (preferably 2 or less).
  • the suffix rl represents an integer of from 1 to 3 (preferably 2 or less).
  • M 1 represents an alkaline metal cation or hydrogen atom.
  • the sum of pi and rl is 3.
  • R or L preferably contains a hydrocarbon group having 8 or more carbon atoms. Most desirable among the compounds represented by the general formula (2-7) is one represented by the following general formula (2-
  • R-N-(L-COOM ! ) 2 R, L and M 1 are as defined in the general formula (2-7).
  • Two (L-COOM 1 ) groups may be the same or different (The two L's and M ⁇ s each may be the same or different).
  • a particularly prefe ⁇ ed example of R is alkyl group.
  • L is preferably an alkylene group.
  • Prefe ⁇ ed examples ofthe betaine-based surface active agent will be given below, but it goes without saying that the invention is not limited thereto.
  • the preferred added amount ofthe betaine-based surface active agent may be arbitrary so far as the effect ofthe invention can be exerted but is preferably from 0.001 to 50% by weight, more preferably from 0.01 to 20% by weight based on the weight ofthe ink composition.
  • the concentration ofthe betaine-based surface active agent in the ink having the highest dye concentration be higher than that 'of the ink having the lowest dye concentration. It is particularly preferred that as the concentration of dye in the ink increases, the content of betaine-based surface active agent increases.
  • k represented by Da Db (Va Vb) is preferably from 0.1 to 10.
  • the ink to be used in the invention is of a type obtained by dissolving and/or dispersing a dye in water or a water-miscible organic solvent.
  • the ink ofthe invention is preferably a water-soluble type of ink comprising a water-soluble dye incorporated therein.
  • the ink comprising a betaine-based surface active agent may have any color but preferably comprises a betaine-based surface active agent incorporated in a yellow ink and/or magenta ink.
  • the ink ofthe invention may comprise other dyes in combination with the dyes ofthe present invention. Examples of these dyes which can be used in combination with the dyes ofthe invention include cyan dyes and black dyes.
  • the physical characteristics ofthe dyes which can be used as the cyan dye and black dye is that they have a l ⁇ gh oxidation potential, the oxidation potential ofthe dyes is preferably more positive than 1.00 V, more preferably more positive than 1.1 V, most preferably more positive than 1.15 V.
  • the cyan dyes there are preferably used those described as water-soluble phthalocyanine dye in JP- A-2003-12952 and JP-A-2003-12956.
  • Specific preferred examples ofthe phthalocyanine dye are Exemplary Compounds I-l to 1-12 and 101 to 190 given in the first embodiment.
  • Preferred embodiments and specific examples ofthe black dye are same as those given in the general formula (1-4) in the first embodiment.
  • these dyes may be singly used as a black ink dye but normally is used in combination with dyes which compensate for these dyes in the range where these dyes have a low absorption.
  • the aforementioned dyes are used in combination with dyes or pigments having main absorption in the yellow range to realize desirable black.
  • yellow dyes there may be used direct dyes or acidic dyes represented by azo dye or azo methine dye which are commonly used.
  • dyes to be used for the adjustment of color tone for full- color image there may be used various dyes disclosed in JP-A-2003-306623, paragraph [0090] - [0092].
  • black coloring material there may be used a dispersion of carbon black.
  • water-miscible organic solvent examples include alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t- butanol, pentanol, hexanol, cyclohexanol, benzylalcohol), polyvalent alcohols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexatriol, tliiodiglycol), glycol derivatives (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether
  • water-miscible organic solvent preferably water-soluble organic solvent
  • a water-miscible organic solvent having a boiling point of 150°C or more (preferably 200°C or more) is preferably used.
  • preferred among the aforementioned water-miscible organic solvents is one (preferably water-soluble organic solvent) having a boiling point of 150°C or more (preferably 170°C or more).
  • the water-miscible organic solvents belonging to the aforementioned glycol derivatives are preferred.
  • glycol derivatives are triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, tripropylene glycol monomethyl ether, and dipropylene glycol monomethyl ether.
  • the water-miscible organic solvent may be used in an amount of from 0.01 to 0.95 times, preferably from 0.01 to 0.7 times the weight ofthe ink composition. These water-miscible organic solvents may be used singly or in admixture.
  • the recording ink (preferably ink for inkjet recording) (composition) may comprise a surface active agent incorporated therein.
  • the liquid physical properties ofthe ink composition can be properly adjusted to enhance the ejection stability ofthe ink composition, making it possible to exert an excellent effect of enhancing the waterproofness ofthe image or preventing the bleeding of ink composition.
  • the aforementioned surface active agents include anionic surface active agents such as sodium dodecylsulfate, sodium dodecyloxysulfbnate and sodium alkylbenzenesulfonate, cationic surface active agents such as cetyl pyridinium chloride, trimethylcetyl ammonium chloride and tetrabutylammonium chloride, and nonionic surface active agents such as polyoxyethylenenonly phenyl ether, polyoxyethylene naphthyl ether and polyoxyethyleneoctylphenyl ether.
  • nonionic surface active agents are nonionic surface active agents.
  • the content ofthe surface active agent is from 0.001 to 15% by weight, preferably from 0.005 to 10% by weight, more preferably from 0.01 to 5% by weight based on the weight ofthe ink composition.
  • nonionic, cationic or anionic surface active agents as surface tension adjuster.
  • anionic surface active agent examples include aliphatic acid salts, acid esters, alkylbenzenesul&nates, alkylnapthalene sulfonates, dialkylsulfosuccinates, alkylphosphoric acid esters, naphthalenesulfonic acid-formalin condensates, and polyoxyethylenealkylsulfuric acid esters.
  • nonionic surface active agent examples include polyoxyethylenealkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylenealiphatic acid esters, sorbitanaliphatic acid esters, polyoxyethylene sorbitanaliphatic acid esters, polyoxyethylene alkylamines, glycerinaliphatic acid esters, and oxyethyleneoxypropylene block copolymers.
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  • acetylene-based polyoxyethylene oxide surface active agents are preferably used as well.
  • the ink for inkjet recording ofthe invention can be prepared by dissolving or dispersing the aforementioned dyes and preferably a surface active agent in an aqueous medium.
  • aqueous medium as used in the invention is meant to indicate water or a mixture of water and a small amount of a water-miscible organic solvent optionally comprising additives such as wetting agent, stabilizer and preservative incorporated therein.
  • the dyes are preferably dissolved in water. Thereafter, various solvents and additives are added to and dissolved in the solution which is then stirred to obtain a uniform ink solution.
  • dissolution method employable herein examples include dissolution by agitation, dissolution by irradiation with ultrasonic wave, and dissolution by shaking. Particularly preferred among these methods is agitation method.
  • agitation method In order to effect stirring, various methods such as fluid agitation known in the art and agitation utilizing shearing force developed by reverse agitator or dissolver may be used.
  • an agitation method utilizing shearing force with respect to the bottom of vessel may be used to advantage.
  • Examples ofthe water-miscible organic solvent employable in the present invention include alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyvalent alcohols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), glycol derivatives (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl
  • the ink can be prepared by emulsion- dispersing the oil-soluble dye in an aqueous medium in the form of solution in a high boiling organic solvent.
  • the boiling point ofthe aforesaid high boiling organic solvent is 150°C or more, preferably 170°C or more.
  • Examples ofthe high boiling organic solvent employable herein include phthalic acid esters (e.g., dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl phthalate, decyl phthalate, bis(2,4- di-tert-amylphenyl) isophthalate, bis(l,l-diethylpropyl)phthalate), phosphoric or phosphonic acid esters (e.g., diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, 2-ethylhexyl diphenyl phosphate, dioctyl butyl phosphate, tricyclohexyl phosphate, tri-2-ethylhexyl phosphate, tridodecyl phosphate, di-2-ethylhexyI phenyl phosphate), benzoic acid esters (e.g.
  • the high boiling organic solvent may be used in an amount of from 0.01 to 3 times, preferably from 0.01 to 1.0 times that ofthe oil-soluble dye.
  • These high boiling organic solvents may be used singly or in admixture of two or more thereof (e.g., tricresyl phosphate and dibutyl phthalate, trioctyl phosphate and di(2-ethylhexyl)sebacate, dibutyl phthalate and poly(N-t-butylacrylamide)).
  • the aforementioned high boiling organic solvents are used in an amount of preferably from 0.01 to 3.0 times, pre preferably from 0.01 to 1.0 times that ofthe oil-soluble dye by weight.
  • the oil-soluble dye and the high boiling organic solvent are used in the form of emulsion dispersion in an aqueous medium.
  • a low boiling organic solvent may be used in some cases from the standpoint of emulsifiability.
  • esters e.g., ethyl acetate, butyl acetate, ethyl propionate, ⁇ -ethoxyethyl acetate, methyl cellosolve acetate
  • alcohols e.g., isopropyl alcohol, n-butyl alcohol, secondary butyl alcohol
  • ketones e.g., methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone
  • amides e.g., dimethylformamide, N-methylpyrrolidone
  • ethers e.g., tetrahydrofurane, dioxane.
  • the present invention is not limited to these organic solvents.
  • the emulsion dispersion is effected to disperse an oil phase having a dye dissolved in a high boiling organic solvent optionally mixed with a low boiling organic solvent in an aqueous phase mainly composed of water to make minute oil droplets of oil phase.
  • additives such as surface active agent, wetting agent, dye stabilizer, emulsion stabilizer, preservative and antifungal agent described later may be added to either or both ofthe aqueous phase and the oil phase as necessary.
  • the emulsification is normally accomplished by adding the oil phase to the aqueous phase, but a so-called phase inversion emulsification method involving the dropwise addition of an aqueous phase to an oil phase is preferably used.
  • the aforementioned emulsification method may be used also in the case where the dye to be used in the invention is water-soluble and the additives are oil-soluble.
  • the emulsion dispersion may be effected with the aforesaid surface active agents.
  • the surface active agents employable herein include amonic surface active agents such as aliphatic acid salt, alkylsulfuric acid ester, alkylberizenesulfonate, alkylnaphthalenesulfonate, dialkylsulfosuccinate, alkylphosphoric acid esters, naphthalenesulfonic acid-formalin condensate and polyoxyethyleneaLkylsulfuric acid ester, and nonionic surface active agents such as polyoxyethylenealkyl ether, polyoxyethylenealkylallyl ether, polyoxyethylene aliphatic acid ester, sorbitanaliphatic acid ester, polyoxyethylenesorbitanaliphatic acid ester, polyoxyethylenealkylamine, glycerinaliphatic acid ester and oxyethyleneoxypropylene block copolymer.
  • amonic surface active agents such as aliphatic acid salt, alkylsulfuric acid ester, alkylberizenesulfonate, alkylna
  • SURFYNOLS produced by Air Products & Chemicals Inc.
  • amine oxide-based amphoteric surface active agents such as N,N-dimethyl-N-alkylamine oxide may be used.
  • Those listed as surface active agents in JP-A-59-157,636, pp. 37 - 38, and Research Disclosure No. 308119 (1989) may be used.
  • the aforementioned surface active agents may be used in combination with a water-soluble polymer.
  • a water-soluble polymer there may be preferably used a polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polyacrylic acid, polyacrylamide or copolymer thereof.
  • natural water-soluble polymers such as polysaccharides, casein and gelatin may be preferably used.
  • polyvinyls obtained by the polymerization of acrylic acid esters, methacrylic acid esters, vinyl esters, acrylamides, methacrylamides, olefins, styrenes, vinylethers or acrylonitriles, polymethanes, polyesters, polyamides, polyureas, polycarbonates, etc., which are substantially insoluble in an aqueous medium, may be used.
  • These polymers preferably have - S0 3 " or -COO " .
  • these polymers substantially insoluble in an aqueous medium are preferably used in an amount of not greater than 20% by weight, preferably not greater than 10% by weight based on the amount ofthe high boiling organic solvent.
  • emulsion dispersion is effected to disperse the oil-soluble dye or high boiling organic solvent to make an aqueous ink
  • a particularly important factor is control over the particle size ofthe aqueous ink.
  • the volume-average particle diameter ofthe aqueous ink is preferably not greater than 1 ⁇ m, more preferably from 5 nm to 100 nm.
  • the measurement ofthe volume-average particle diameter and the particle size distribution ofthe dispersed particles can be easily accomplished by any known method such as static light scattering method, dynamic light scattering method, centrifugal sedimentation method and method as disclosed in "Jikken Kagaku Koza (Institute of Experimental Chemistry)", 4th ed., pp. 417 - 418.
  • measurement can be easily carried out by diluting the ink with distilled water such that the particle concentration in the ink reaches 0.1% to 1% by weight, and then subjecting the solution to measurement using a commercially available volume-average particle diameter measuring instrument (e.g., Microtrack UPA (produced by NIKKISO CO., LTD.).
  • volume-average particle diameter is meant to indicate average particle diameter weighted with particle volume, which is obtained by dividing the sum ofthe product ofthe diameter and the volume of individual particles in the aggregate of particles by the total volume of the particles.
  • volume-average particle diameter reference can be made to Souic i Muroi, "Koubunshi Ratekkusu no Kagaku (Chemistry of Polymer Latexes)", Koubunshi Kankokai, page 119. It was also made obvious that the presence of coarse particles has an extremely great effect on the printing properties. In other words, coarse particles clog the head nozzle.
  • the ink cannot be ejected or can be deviated when ejected, giving a serious effect on the printing properties.
  • the removal of these coarse particles can be accomplished by any known method such as centrifugal separation method and precision filtration method.
  • the separation step may be effected shortly after emulsion dispersion or shortly before the filling ofthe emulsion dispersion comprising various additives such as wetting agent and surface active agent in the ink cartridge.
  • a mechanical emulsifier As an effective unit for reducing the average particle diameter of particles and eliminating coarse particles there maybe used a mechanical emulsifier.
  • an emulsifier there may be used any known device such as simple stirrer, impeller type agitator, in-line agitator, mill type agitator (e.g., colloid mill) and ultrasonic agitator.
  • the use of a high pressure homogenizer is particularly preferred.
  • examples of commercially available high pressure homogenizers include Gaulin homogenizer (produced by A. P.
  • a high pressure homogenizer having a mechanism for atomizing a material in a ultrahigh pressure jet stream as disclosed in US Patent 5,720,551 is particularly useful in the emulsion dispersion of the invention.
  • An example of the emulsifier using a ultrahigh jet stream is De BEE2000 (produced by BEE TNTERNATIONAL LTD.).
  • the pressure at which emulsion is carried out by a high pressure emulsion disperser is not lower than 50 MPa, preferably not lower than 60 MPa, more preferably not lower than 180 MPa.
  • the combined use of two or more emulsifiers as in a method involving the emulsification by an agitated emulsifier followed by the passage through a high pressure homogenizer is particularly preferred.
  • a method is preferably used which comprises effecting the emulsion ofthe material using such an emulsifier, adding additives such as wetting agent and surface active agent, and then passing the ink composition again through the high pressure homogenizer before being filled in the cartridge.
  • the dye composition comprises a low boiling organic solvent incorporated therein in addition to the high boiling organic solvent, it is preferred to remove the low boiling organic solvent from the standpoint of emulsion stability and safety/hygiene.
  • the removal of the low boiling solvent can be accomplished by any known method such as evaporation method, vacuum evaporation method and ultrafiltration method depending on the solvent to be removed.
  • the step of removing the low boiling organic solvent is preferably effected as rapidly as possible shortly after emulsification.
  • JP-A-5-148436, JP-A-5-295312, JP-A-7-97541, JP-A-7-82515, and JP-A-7-118584 can be used also in the preparation ofthe ink for inkjet recording ofthe invention.
  • ultrasonic vibration may be applied at the step of dissolving additives such as dye and like steps.
  • an ultrasonic energy equal to or greater than the energy received by the recording head has been previously applied during the production ofthe ink to remove bubbles, preventing the generation of bubbles due to the pressure applied to the ink by the recording head.
  • the ultrasonic vibration is an ultrasonic wave having a frequency of normally 20 kHz or more, preferably 40 kHz or more, more preferably 50 kHz.
  • the energy applied to the solution by the ultrasonic vibration is normally 2 x 10 7 J/m 3 or more, preferably 5 x 10 7 J/m 3 or more, more preferably 1 x 10 8 J/m 3 or more.
  • the time during which the ultrasonic vibration is applied is normally from about 10 minutes to 1 hour.
  • the step of applying ultrasonic vibration may be effected at any time after the incorporation ofthe dye in the medium to exert the effect. Even when the ultrasonic vibration is applied after the storage ofthe ink completed, the effect can be exerted.
  • the ultrasonic vibration be applied during the dissolution and/or dispersion of the dye in the medium because the effect of removing bubbles can be more exerted and the dissolution and/or dispersion ofthe dyestuff in the medium can be accelerated by the ultrasonic vibration.
  • the aforementioned step of applying at least ultrasonic vibration may be effected either during or after the step of dissolving and/or dispersing the dye in the medium.
  • the aforementioned step of applying at least ultrasonic vibration may be effect one or more times between after the preparation ofthe ink and the completion ofthe product.
  • the step of dissolving and or dispersing the dye in the medium preferably involves a step of dissolving the aforementioned dye in a part ofthe entire medium and a step of adding the rest ofthe medium, and it is preferred that ultrasonic vibration be applied at any ofthe aforementioned steps, more preferably at the step of dissolving the dye in a part ofthe entire medium.
  • the aforementioned step of adding the rest ofthe medium may consist of a single step or a plurality of steps.
  • the process for the production of the ink according to the present invention is preferably accompanied by heat deaeration or deaeration under reduced pressure to enhance the effect of removing bubbles from the ink.
  • Heat deaeration or vacuum deaeration is preferably effected at the same time with or after the step of adding the rest of the medium to the solution.
  • the unit for generating sound vibration at the step of giving sound vibration include known devices such as ultrasonic dispersing machine.
  • a filter is used, and, as such a filter there is used a filter having an effective pore diameter of 1 ⁇ m or less, preferably from 0.05 ⁇ m to 0.3 ⁇ m, particularly from 0.25 ⁇ m to 0.3 ⁇ m.
  • the filter material there may be used any of various known materials, and, in the case where a water-soluble dye ink is used, a filter prepared for aqueous solvent is preferably used.
  • a filter made of a polymer material which can difficultly give dust is preferably used. Filtration may be accomplished by pumping the solution through the jacket or may be effected under pressure or reduced pressure. Filtration is often accompanied by the entrapment of air in the solution. Since bubbles due to air thus entrapped can often cause disturbance in image in the inkjet recording, the aforementioned deaeration step is preferably provided separately.
  • the deaeration method there may be used a method which comprises allowing the solution thus filtered to stand or various methods such as ultrasonic deaeration and vacuum deaeration using commercially available apparatus.
  • the ultrasonic deaeration process if effected, preferably lasts for about 30 seconds to 2 hours, more preferably for about 5 minutes to 1 hour.
  • These jobs are preferably effected in a space such as clean room and clean bench to prevent the contamination by dust. In the present invention, these jobs are preferably effected in a space having a cleanness degree of 1,000 class or less.
  • the term "cleanness" as used herein is meant to indicate the value counted by a dust counter.
  • the ink for inkjet recording ofthe invention may comprise properly selected additives incorporated therein in a proper amount such as drying inhibitor for preventing the clogging ofthe ejection nozzle with dried ink, penetration accelerator for helping the ink to penetrate in the page, ultraviolet absorber, oxidation inhibitor, viscosity adjuster, surface tension adjuster, dispersant, dispersion stabilizer, antifungal agent, rust preventive, pH adjuster, anti-foaming agent and chelating agent.
  • drying inhibitor there is preferably used a water-soluble organic solvent having a lower vapor pressure than water.
  • the water-soluble organic solvent include polyvalent alcohols such as ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodigycol, 2-methyl- 1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivative, glycerin and trimethylolpropane, lower alkylethers of polyvalent alcohol such as ethylene glycol monomethyl(or ethyl) ether, diethylene glycol monomethyl(or ethyl)ether and triethylene glycol monoethyl(or butyl)ether, heterocyclic compounds such as 2- pyrrolidone, N-methyl-2-pyrrolidone, l,3-dimethyl-2-imidazolidinone and N-ethylmo ⁇ holine, sulfur-containing compounds such as sulfolane, dimethylsulfoxide and 3-sulfolene, polyfunctional compounds such as diacetone alcohol and ( ethanolamine
  • water-soluble organic solvents are polyvalent alcohols such as glycerin and diethylene glycol. These drying inhibitors may be used singly or in combination of two or more thereof. These drying inhibitors are preferably incorporated in the ink in an amount of from 10% to 50% by weight.
  • the penetration accelerator employable in the present invention include alcohols such as ethanol, isopropanol, butanol, di(tri)ethylene glycol monobutyl ether and 1,2-hexanediol, sodium laurylsulfate, sodium oleate, and nonionic surface active agents. These penetration accelerators can exert a sufficient effect when incorporated in the ink in an amount of from 10% to 30% by weight.
  • the oxidation inhibitor to be used to enhance the image preservability there may be used any of various organic and metal complex-based discoloration inhibitors.
  • the organic discoloration inhibitors include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocyclic compounds.
  • the metal complex-based discoloration inhibitors include nickel complex, and zinc complex. Specific examples of these oxidation inhibitors include compounds listed in the patents cited in Research Disclosure No.
  • the antifungal agent to be incorporated in the present invention include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1 -oxide, ethyl p-hydroxybenzoate, 1,2- benzoisothiazoline-3-one, and salts thereof.
  • antifungal agents are preferably incorporated in the ink in an amount of from 0.02% to 5.00% by weight.
  • Bokin Bobizai Jiten Dictionary Compilation Committee of The Society for Antibacterial and Antifungal Agents, Japan.
  • the rust preventive employable herein include acidic sulfites, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerthyritol tetranitrate, dicyclohexylammonium nitrite, and benzotriazole.
  • These rust preventives are preferably incorporated in the ink in an amount of from 0.02% to 5.00% by weight.
  • the pH adjustor to be incorporated in the ink for ink set of the invention is preferably used for the purpose of adjusting the pH value ofthe ink, providing dispersion stability or like purposes. It is preferred that the pH value ofthe ink be adjusted to a range of from 8 to 11 at 25°C. When the pH value ofthe ink falls below 8, the resulting dye composition exhibits a deteriorated solubility, causing nozzle clogging. On the contrary, when the pH value ofthe ink exceeds 11, the resulting ink tends to exhibit a deteriorated water resistance.
  • Examples ofthe pH adjustor include basic pH adjustors such as organic base and inorganic alkali, and acidic pH adjustors such as organic acid and inorganic acid.
  • Examples ofthe basic compounds employable herein include inorganic compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium acetate, potassium acetate, sodium phosphate and disodium hydrogenphosphate, and organic bass such as aqueous ammonia, methylamine, ethylamine, dietliylamine, triethylamine, etlianolamine, cuethanolamine, triethanolamine, ethylenediamine, piperidine, diazabicyclooctane, diazabicycloundecene, pyridine, quinoline, picoline, lutidine and collidine.
  • Examples ofthe acidic compounds employable herein include inorganic compounds such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, sodium hydrogensulfate, potassium hydrogensulfate, potassium dihydrogenphosphate and sodium dihydrogenphosphate, and organic compounds such as acetic acid, tartaric acid, benzoic acid, trifluoroacetic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfbnic acid, saccharinic acid, phthalic acid, picolic acid and quinolinic acid.
  • the electrical conductance ofthe ink ofthe invention falls within a range of from 0.01 to 10 S/m.
  • a particularly preferred range of electrical conductance is from 0.05 to 5 S/m.
  • the measurement of electric conductance can be accomplished by en electrode method using a commercially available saturated potassium chloride.
  • the electric conductance ofthe ink can be controlled mainly by the ionic concentration ofthe aqueous solution.
  • desalting may be effected using a ultrafiltration membrane or the like.
  • various organic or inorganic salts may be added.
  • inorganic salts there may be used inorganic compounds such as potassium halide, sodium halide, sodium sulfate, potassium sulfate, sodium hydrogensulfate, potassium hydrogensulfate, sodium nitrate, potassium nitrate, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium phosphate, disodium hydrogenphosphate, boric acid, potassium dihydrogenphosphate and sodium dihydrogenphosphate.
  • Organic compounds such as sodium acetate, potassium acetate, potassium tartrate, sodium tartrate, sodium benzoate, potassium benzoate, sodium p-toluenesulfbnate, potassium saccharinate, potassium phthalate and sodium picolate may be used.
  • the ink ofthe invention exliibits a viscosity of from 1 to 20 mPa-s, more preferably from 2 to 15 mPa-s, particularly from 2 to 10 mPa-s at 25°C.
  • the viscosity ofthe ink exceeds 30 mPa-s, the resulting recorded image can be fixed only at a reduced rate. Further, the resulting ink exliibits a deteriorated ejectability. On the contrary, when the viscosity ofthe ink falls below 1 mPa-s, the resulting recorded image runs and thus exhibits a reduced quality.
  • the adjustment of viscosity can be arbitrarily carried out by controlling the added amount ofthe ink solvent.
  • the ink solvent employable herein include glycerin, diethylene glycol, triethanolamine, 2- pyrrolidone, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether.
  • a viscosity adjustor may be used.
  • the viscosity adjustor employable herein include celluloses, water-soluble polymers such as polyvinyl alcohol, and nonionic surface active agents.
  • the viscosity of liquid can be simply measured using a commercially available viscometer.
  • the rotary viscometer include Type B viscometer and Type E viscometer produced by Tokyo Keiki Kogyo K.K.
  • a Type VM-100A-L vibration viscometer (produced by YAMAICHI ELECTRONICS CO., LTD.) was used to measure viscosity at 25°C.
  • the unit of viscosity is Pa-s. In practice, however, mPa-s is used.
  • the surface tension, regardless of which it is static or dynamic, of the ink to be used in the invention is preferably from 20 to not greater than 50 mN/m, more preferably from 20 to not greater than 40 mN/m at 25°C.
  • the surface tension ofthe ink exceeds 50 mN/m, the resulting ink exhibits a drastic deterioration in print quality such as ejection stability and resistance to running and whisker during color mixing.
  • the surface tension ofthe ink falls below 20 mN/m, the resulting ink can be attached to hard surface when ejected, causing defective printing.
  • the aforementioned various cationic, anionic and nonionic surface active agents may be added also for the pmpose of adjusting surface tension.
  • These surface active agents are preferably used in an amount of from 0.01 to 20% by weight, more preferably from 0.1 to 10% by weight based on the weight ofthe ink for inkjet recording. Two or more of these surface active agents may be used in combination.
  • the static surface tension measuring method include capillary rise method, dropping method, and ring method.
  • the static surface tension measuring method there is used a pe ⁇ endicular plate method. When a thin glass or platinum plate is hanged partially dipped in a liquid, surface tension ofthe liquid acts downward along the length ofthe plate in contact with the liquid. The surface tension is measured by balancing this force by a upward force.
  • the bubble rate (rate of formation of bubbles) is changed. As the formation rate decreases, more surface active agent components gather on the surface of bubbles, reducing the maximum bubble pressure shortly before the burst of bubbles. Thus, the maximum bubble pressure (surface tension) with respect to bubble rate can be detected.
  • a method for the measurement of dynamic surface tension there is preferably used a method which comprises forming bubbles in a solution using a large probe and a small probe, measuring the differential pressure ofthe two probes in the state of maximum bubble pressure, and then calculating the dynamic surface tension from the differential pressure.
  • the content of no-volatile components in the ink ofthe invention is preferably from 10% to 70% by weight based on the total amount of the ink from the standpoint of enhancement of ejection stability of ink, printed image quality and various fastnesses of image and elimination of running of printed image and stickiness of printed surface, more preferably from 20% to 60% by weight from the standpoint of enhancement of ejection stability of ink and elimination of running of printed image.
  • non-volatile component as used herein is meant to indicate a liquid, solid or polymer component having a boiling point of not lower than 150°C at 1 atm.
  • the non-volatile components to be inco ⁇ orated in the ink for inkjet recording include dyes, and high boiling solvents, and polymer latexes, surface active agents, dye stabilizers, antifungal agents and buffers which are optically added. Most of these non-volatile components but dye stabilizers deteriorate the dispersion stability ofthe ink. Further, these nonvolatile components are still present on the inkjet image-receiving paper after printing, inhibiting the stabilization of dyes by association on the image-receiving paper and hence deteriorating various fastnesses of the image area and worsening the image running at high temperature and humidity.
  • the ink may comprise a polymer compound inco ⁇ orated therein.
  • polymer compound as used herein is meant to indicate all polymer compounds having a number-average molecular weight of not smaller than 5,000 contained in the ink.
  • examples of these polymer compounds include water- soluble polymer compounds substantially soluble in an aqueous medium, water-dispersible polymer compounds such as polymer latex and polymer emulsion, and alcohol-soluble polymer compounds soluble in polyvalent alcohols used as auxiliary solvents. All polymer compounds are included in the polymer compounds ofthe invention so far as they can be substantially uniformly dissolved or dispersed in the ink solution.
  • water-soluble polymer compounds employable herein include water-soluble polymers such as polyvinyl alcohol, silanol-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyalkylene oxide (e.g., polyethylene oxide, polypropylene oxide) and polyalkylene oxide derivative, natural water-soluble polymers such as polysaccharide, starch, cationated starch, casein and gelatin, aqueous acrylic resins such as polyacrylic acid, polyacrylamide and copolymer thereof, aqueous alkyd resins, and water-soluble compounds which have -S0 3 ⁇ or -COO " group and thus are substantially soluble in an aqueous medium.
  • water-soluble polymers such as polyvinyl alcohol, silanol-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyalkylene oxide (e.g
  • polymer latexes examples include styrene-butadiene latexes, styrene-acryl latexes, and polyurethane latexes.
  • polymer emulsions examples include acryl emulsions.
  • These water-soluble polymer compounds may be used singly or in combination of two or more thereof. Such a water-soluble polymer compound is used as a viscosity adjustor to adjust the ink viscosity to a value falling within a range that provides the ink a good ejectability.
  • the added amount ofthe polymer compound to be used as a viscosity adjustor depends on the molecular weight ofthe polymer compound added (The greater the molecular weight ofthe polymer compound to be added is, the smaller is the added amount thereof) but is normally from 0% to 5% by weight, preferably from 0% to 3% by weight, more preferably from 0% to 1% by weight based on the total amount ofthe ink composition.
  • nonionic, cationic or amonic surface active agents as surface tension adjustor.
  • anionic surface active agent include aliphatic acid salts, alkylsulfuric acid esters, alkylbenzenesulfonates, alkylnapthalenesulfonates, dialkylsulfosuccinates, alkylphosphoric acid esters, naphthalenesulfonic acid-formalin condensates, and polyoxyethylenealkylsulfuric acid esters.
  • nonionic surface active agent examples include polyoxyethylenealkyl ethers, polyoxyethylenealkyl allyl ethers, polyoxyethylenealiphatic acid esters, sorbitanaliphatic acid esters, polyoxyethylene sorbitanaliphatic acid esters, polyoxyethylene alkylamines, glycerinaliphatic acid esters, and oxyethyleneoxypropylene block copolymers.
  • SURFYNOLS produced by Air Products & Chemicals Inc.
  • amine oxide-based amphoteric surface active agents such as N,N-mmethyl-N-alkylamine oxide are preferred.
  • the dispersant and dispersion stabilizer there may be used the aforementioned various cationic, anionic and nonionic surface active agents as necessary.
  • the anti-forming agent there may be used a fluorine-based or silicone-based compound or a chelating agent such as EDTA as necessary.
  • image-receiving material As the image-receiving material there may be used a recording paper or recording film which is a reflection medium described hereinafter.
  • the support in the recording paper or recording film there may be used one obtained by processing a chemical pulp such as LBKP and NBKP, a mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMP and CGP, used paper pulp such as DIP or the like, optionally mixed with known additives such as pigment, binder, sizing agent, fixing agent, cationic agent and paper strength improver, through various paper machines such as foundrinier paper machine and cylinder paper machine.
  • a synthetic paper or plastic film sheet besides tliese support materials.
  • the thickness of the support is preferably from 10 ⁇ m to 250 ⁇ m.
  • the basis weight ofthe support is preferably from 10 to 250 g/m 2 .
  • An ink-receiving layer and a back coat layer may be provided on the support directly or with a size press or anchor coat layer of starch, polyvinyl alcohol or the like inte ⁇ osed therebetween to prepare a material for receiving the ink ofthe invention.
  • the support may be further subjected to leveling using a calendering machine such as machine calender, TG calender and soft calender.
  • a calendering machine such as machine calender, TG calender and soft calender.
  • the polyolefin preferably comprises a white pigment (e.g., titanium oxide, zinc oxide) or a tinting dye (e.g., cobalt blue, ultramarine, neodymium oxide) inco ⁇ orated therein.
  • the ink-receiving layer to be provided on the support comprises a porous material or aqueous binder inco ⁇ orated therein.
  • the image receiving layer (ink-receiving layer) also preferably comprises a pigment inco ⁇ orated therein. As such a pigment there is preferably used an inorganic white pigment (particles).
  • the inorganic white pigments include calcium carbonate, kaolin, talc, clay, diatomaceous earth, synthetic amo ⁇ hous silica, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, alumina, lithopone, zeolite, barium sulfate, calcium sulfate, titanium dioxide, zinc sulfate and zinc carbonate, and organic pigments such as styrene-based pigment, acrylic pigment, urea resin and melamine resin. Particularly preferred among these pigments are porous inorganic white pigments. In particular, synthetic amo ⁇ hous silica having a large pore area, etc. are preferred.
  • the synthetic amo ⁇ hous silica there may be also used anhydrous silicate obtained by dry method or hydrous silicate obtained by wet method, but hydrous silicate is particularly preferred.
  • These pigments may be used in combination of two or more thereof.
  • Specific examples ofthe recording paper comprising the aforementioned pigments inco ⁇ orated in the image-receiving layer include those disclosed in JP-A-10-81064, JP-A-10-119423, JP-A-10-157277, JP-A-10- 217601, JP-A-11-348409, JP-A-2001-138621, JP-A-2000-43401, JP-A-2000-211235, JP-A-2000-309157, JP-A- 2001-96897, JP-A-2001-138627, JP-A-11-91242, JP-A-8-2087, JP-A-8-2090, JP-A-8-2091, JP-A-8-2093, JP-A- 174992, JP-A-11-
  • aqueous binder to be inco ⁇ orated in the image-receiving layer examples include water-soluble polymers such as polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationated starch, casein, gelatin, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyalkylene oxide and polyalkylene oxide derivative, and water-dispersible polymers such as styrene butadiene latex and acryl emulsion. These aqueous binders may be used singly or in combination of two or more thereof.
  • tliese aqueous binders are polyvinyl alcohol and silanol-modified polyvinyl alcohol from the standpoint of adhesion to pigment and exfoliation resistance of ink-receiving layer.
  • the ink-receiving layer may comprise a mordant, a wate ⁇ roofing agent, a light-resistance improver, a gas resistance improver, a surface active agent, a film hardener and other additives inco ⁇ orated therein besides the pigments and aqueous binders.
  • the mordant to be inco ⁇ orated in the image-receiving layer is preferably passivated. To this end, a polymer mordant is preferably used.
  • An image-receiving material containing a polymer mordant disclosed in JP-A-1-161236, pp. 212 to 215 is particularly preferred.
  • the use ofthe polymer mordant disclosed in the above cited patent makes it possible to obtain an image having an excellent quality and hence improve the light-resistance ofthe image.
  • the wate ⁇ roofing agent can be used to render the image wate ⁇ roof.
  • a wate ⁇ roofing agent there is preferably used a cationic resin in particular.
  • a cationic resin include polyamide polyamine epichlorohydnn, polyethylenimine, polyamine sulfone, dimethyl diallyl ammonium chloride polymer, and cation polyacrylamide.
  • cationic resins are polyamine epichlorohydrin.
  • the content of such a cationic resin is preferably from 1% to 15% by weight, particularly from 3% to 10% by weight based on the total solid content ofthe ink-receiving layer.
  • Examples ofthe light-resistance improver and gas resistance improver include phenol compounds, hindered phenol compounds, thioether compounds, thiourea compounds, thiocyanic acid compounds, amine compounds, hindered amine compounds, TEMPO compounds, hydrazine compounds, hydrazide compounds, amidine compounds, vinyl-containing compounds, ester compounds, amide compounds, ether compounds, alcohol compounds, sulfinic acid compounds, saccharides, water-soluble reducing compounds, organic acids, inorganic acids, hydroxyl-containing organic acids, benzotriazole compounds, benzophenone compounds, triazine compounds, heterocyclic compounds, water-soluble metal salts, organic metal compounds, and metal complexes.
  • Examples of these compounds include those disclosed in JP-A-10-182621, JP-A-2001-260519, JP-A-2000-260519, JP-B-4-34953, JP-B-4-34513, JP-B-4-34512, JP-A-11-170686, JP-A-60-67190, JP-A-7- 276808, JP-A-2000-94829, JP-T-8-512258, and JP-A-11-321090.
  • Examples ofthe light-resistance improver include zinc sulfate, zinc oxide, hindered amine-based oxidation inhibitor, and benzotriazole-based ultraviolet absorber such as benzophenone.
  • the surface active agent acts as a coating aid, releasability improver, slipperiness improver or antistat.
  • the surface active agent acts as a coating aid, releasability improver, slipperiness improver or antistat.
  • the surface active agent is preferably hydrophobic.
  • the organic fluoro-compound include fluorine-based surface active agents, oil-based fluorine compounds (e.g., fluorine-based oil), and solid fluorine-based compound resins (e.g., tetrafluoroethylene resin).
  • JP-B- 57-9053 (8th to 17th columns), JP-A-61-20994, and JP-A-62-135826.
  • the film hardener there may be used any of materials disclosed in JP-A-1-161236, page 222, JP-A-9- 263036, JP-A-10-119423, and JP-A-2001-310547.
  • additives to be inco ⁇ orated in the image-receiving layer include pigment dispersants, thickening agents, antifoaming agents, dyes, fluorescent brighteners, preservatives, pH adjustors, matting agents, and film hardeners.
  • the recording paper and recording film may comprise a back coat layer provided thereon.
  • the components which can be inco ⁇ orated in the back coat layer include white pigments, aqueous binders, and other components.
  • Examples ofthe white pigments to be inco ⁇ orated in the back coat layer include inorganic white pigments such as light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amo ⁇ hous silica, colloidal silica, colloidal alumina, pseudo- boehmite, aluminum hydroxide, alumina, lithopone, hydrated halloysite, magnesium carbonate and magnesium hydroxide, and organic pigments such as styrene-based plastic pigment, acrylic plastic pigment, polyethylene, microcapsule, urea resin and melamine resin.
  • inorganic white pigments such as light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate
  • aqueous binder to be inco ⁇ orated in the back coat layer examples include water-soluble polymers such as styrene/maleate copolymer, styrene/acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationated starch, casein, gelatin, carboxymefhyl cellulose, hydroxyethyl cellulose and polyvinylpyrrolidone, and water-dispersible polymers such as styrenebutadiene latex and acryl emulsion.
  • water-soluble polymers such as styrene/maleate copolymer, styrene/acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationated starch, casein, gelatin, carboxymefhyl cellulose, hydroxyethyl cellulose and polyvinylpyrrolidone, and water-disp
  • Examples of other components to be inco ⁇ orated in the back coat layer include antifoaming agents, foaming inhibitors, dyes, fluorescent brightening agents, preservatives, and wate ⁇ roofing agents.
  • the layers (including back layer) constituting the ink et recording paper and film may comprise a fine dispersion of polymer inco ⁇ orated therein.
  • the fine dispersion of polymer is used for the pu ⁇ ose of improving physical properties of film, e.g., stabilizing dimension, inhibiting curling, adhesion and film cracking.
  • JP-A-62-245258, JP-A-62-1316648, and JP- A-62-110066 for the details ofthe fine dispersion of polymer, reference can be made to JP-A-62-245258, JP-A-62-1316648, and JP- A-62-110066.
  • the inco ⁇ oration of a fine dispersion of polymer having a glass transition temperature as low as not higher than 40°C in a layer containing a mordant makes it possible to prevent the cracking or curling ofthe layer.
  • the inco ⁇ oration of a fine dispersion of polymer having a high glass transition temperature, too, in the back layer makes it possible to prevent the curling ofthe back layer.
  • the volume ofthe droplet to be ejected onto the ink recording material ofthe invention is from not smaller than 0.1 pi to not greater than 100 pi, preferably from not smaller than 0.5 pi to not greater than 50 pi, particularly from not smaller than 2 pi to not greater than 50 pi. In the present invention, the inkjet recording method is not limited.
  • the ink of the present invention may be used in any known recording method such as electrostatic control method which utilizes electrostatic attraction to eject ink, drop-on-demand method (pressure pulse method) utilizing vibrational pressure of piezoelectric element, acoustic inkjet method which comprises converting electrical signal to acoustic beam with which the ink is irradiated to produce a radiation pressme that is utilized to eject the ink and thermal inkjet (bubble jet (registered trademark)) method which comprises heating the ink to form bubbles that raise the pressure to eject the ink.
  • electrostatic control method which utilizes electrostatic attraction to eject ink
  • drop-on-demand method pressure pulse method
  • acoustic inkjet method which comprises converting electrical signal to acoustic beam with which the ink is irradiated to produce a radiation pressme that is utilized to eject the ink
  • thermal inkjet bubble jet (registered trademark)) method which comprises heating the ink to form bubbles that
  • Examples ofthe inkjet recording method include a method which comprises ejecting many portions of an ink having a low concentration called photoink in a small volume, a method which comprises using a plurality of inks having substantially the same hue but different densities to improve the image quality, and a method involving the use of a colorless transparent ink.
  • the volume ofthe ink droplet to be ejected is controlled mainly by the print head.
  • the volume of the ink droplet to be ejected can be controlled by the structure ofthe print head.
  • the ink droplet can be ejected in a desired size by properly changing the size ofthe ink chamber, heating zone and nozzle.
  • the ink droplet can be ejected in a plurality of sizes by using a plurality of print heads comprising heating zones and nozzles having different sizes.
  • the volume ofthe ink droplet to be ejected can be varied due to the structure of the print head as in the thermal ink jet recording system.
  • the waveform ofthe driving signal for driving the piezoelectric element the ink droplet can be ejected in a plurality of sizes by the same structure of print head.
  • the frequency at which the ink droplet is ejected onto the recording material is not lower than 1 kHz.
  • the ejection density be not smaller than 600 dpi (number of dots per inch) to reproduce an image having a high sha ⁇ ness with small ink droplets.
  • the number of heads which can be driven at the same time in a type of recording system involving the cross movement ofthe recording paper and the head is from scores to about 200. Even in a type having heads called line heads fixed therein, the number of heads which can be driven at the same time is limited to hundreds.
  • the control over the ejection frequency in the case of thermal inkjet recording system can be accomplished by controlling the frequency ofthe head driving signal for heating the head.
  • the control over the ejection frequency can be accomplished by controlling the frequency ofthe signal for driving the piezoelectric element.
  • the driving of piezoelectric element will be described hereinafter.
  • the image signal to be printed is made as follows.
  • the size of ink droplet to be ejected, the ejection rate and the ejection frequency are determined at the printer control.
  • the signal for driving the print head is developed.
  • the driving signal thus developed is then supplied into the print head.
  • the size of ink droplet to be ejected, the ejection rate and the ejection frequency are controlled by the signal for driving the piezoelectric element.
  • the size of ink droplet to be ejected and the ejection rate are determined by the shape and amplitude ofthe driving waveform and the ejection frequency is determined by the repetition frequency ofthe signal.
  • the ejection frequency is predetermined to 10 kHz, the head is driven every 100 microseconds. One line of recording is finished in 400 microseconds.
  • the configuration ofthe printing device using the ink for inkjet recording ofthe invention can be applied is preferably in an embodiment disclosed in JP-A-11-170527.
  • the configuration ofthe ink cartridge to which the invention can be applied is preferably in an embodiment disclosed in JP-A-5-229133.
  • the configuration ofthe suction system and the cap covering the print head 28 are preferably in an embodiment disclosed in JP-A-7-276671. It is preferred that a filter for evacuating bubbles as disclosed in JP-A-9-277552 be provided in the vicinity ofthe head.
  • the surface ofthe nozzle is preferably subjected to water repellent treatment as disclosed in Japanese Patent No. 2001-016738.
  • the invention may be used with a printer connected to computer.
  • the invention may be used with an apparatus dedicated for printing photograph.
  • the ink for inkjet recording ofthe invention is preferably ejected onto the recording material at an average rate of not smaller than 2 m/sec, preferably not smaller than 5 m/sec.
  • the control over the ejection rate is accomplished by controlling the form and amplitude of the signal for driving the head. By using a plurality of driving waveforms properly, ink droplets having a plurality of sizes can be ejected by the same head.
  • the ink for inkjet recording medium ofthe present invention may be used pmposes other than inkjet recording such as display image material, image-forming material for indoor decoration material, and image- forming material for outdoor decoration material.
  • display image material include various materials such as poster, wall paper, small decoration articles (ornament, doll, etc.), commercial flyer, wrapping paper, wrapping material, paper bag, vinyl bag, packaging material, signboard, picture drawn or attached to the side of traffic facilities (automobile, bus, train, etc.) and clothing with logogram.
  • the term "image” as used herein means an image in a narrow sense as well as all dye patterns perceivable by human being such as abstract design, letter and geometrical pattern.
  • the term "indoor decoration material” as used herein is meant to include various materials such as wall paper, small decoration articles (ornament, doll, etc.), members of lighting fixture, members of furniture and design members of floor and ceiling.
  • image as used herein means an image in a narrow sense as well as all dye patterns perceivable by human being such as abstract design, letter and geometrical pattern.
  • outdoor decoration material as used herein is meant to include various materials such as wall material, roofing material, signboard, gardening material, small outdoor decoration articles (ornament, doll, etc.) and members of outdoor lighting fixture.
  • image as used herein means an image in a narrow sense as well as all dye patterns perceivable by human being such as abstract design, letter and geometrical pattern.
  • the media on which patterns are formed in these uses include various materials such as paper, fiber, cloth (including nonwoven cloth), plastic, metal and ceramics.
  • Dyeing can be carried out by mordanting or printing. Alternatively, a dye can be fixed in the form of reactive dye having a reactive group inco ⁇ orated therein.
  • Example 1 The first embodiment ofthe invention will be further described in the following examples, but the invention is not construed as being limited thereto.
  • Example 1-1 To the following components was added ultrapure water having a resistivity of 18 M ⁇ or more to make 1 1. The mixture was then heated to a temperature of from 30°C to 40°C with stirring for 1 hour. Thereafter, the solution was filtered through a microfilter having an average pore diameter of 0.25 ⁇ m under reduced pressure to prepare various color ink solutions.
  • 2-Pyrrolidone (PRD) 60 g/1
  • Magenta dye (M-1) shown above 23 g ⁇ Urea (UR) 15 g ⁇ PROXEL XL2 (PXL) 5 g/1 (Liquid component)
  • Diethylene glycol (DEG) 90 g ⁇ Glycerin (GR) 70 g ⁇ Triethylene glycol monobutyl ether (TGB) 70 g/1 Triethanolamine (TEA) 6.9 g ⁇ Surfynol STG (SW) 10 g/1
  • ink set comprising these inks was refened to as "IS-101".
  • Ink sets IS-102 to 108 shown below were then prepared from the same inks except that the dye for yellow ink was changed to one according to the invention or other compounds.
  • the aforementioned dyes ofthe invention were each measured for potential in the form of 1 mmolTl aqueous solution by dropping mercury electrode polarography. As a result, all these dyes showed a higher potential than 1.2 V/vsSCE.
  • These inks were each packed in the ink cartridge of a Type PM-980C ink jet printer (produced by EPSON Co., Ltd.). Using this inkjet printer, a standard image pattern was printed in a 6-color mode.
  • the image sheet used herein was prepared according to the following fonnulation.
  • the mixture was then again subjected to dispersion at a rotary speed of 10,000 ⁇ m for 20 minutes to prepare a coating solution A for coloring material-receiving layer.
  • the pH value ofthe coating solution A for coloring material-receiving layer was 3.5, which is acidic.
  • Gas phase process particulate silica (inorganic particulate material) (Reolosil QS-30; average primary particle diameter: 7 nm; produced by TOKUYAMA CORP.) 10.0 parts
  • PAS-M-1 50% aqueous solution 0.83 parts (dispersant produced by Nitto Boseki Co., Ltd.)
  • a 200- ⁇ m thick paper support laminated with a polyethylene was subjected to corona discharge treatment on one surface thereof.
  • the coating solution A for coloring material-receiving layer obtained above was spread over the same surface ofthe support at a rate of 200 ml/m 2 (coating step), and then dried at 80°C in a hot air drier (wind velocity: 3 to 8 m/second) until the solid concentration ofthe coat layer reached 20%.
  • the coat layer exhibited a constant drying rate.
  • the coated support was immediately dipped in a mordant solution B having the following formulation for 30 seconds so that the mordant solution B was attached to the coat layer in an amount of 20 g/m 2 (step of providing a mordant solution), and then dried at 80°C for 10 minutes (drying step).
  • a mordant solution B having the following formulation for 30 seconds so that the mordant solution B was attached to the coat layer in an amount of 20 g/m 2 (step of providing a mordant solution), and then dried at 80°C for 10 minutes (drying step).
  • an inventive inkjet recording sheet R-l having a coloring material-receiving layer provided thereon to a dried thickness of 32 ⁇ m was prepared.
  • Image-receiving papers R-2 and R-3 were prepared in the same manner as the inkjet recording sheet R- 1 except that the mordant polymer was changed from the polyarylamine to the inventive polymers P-1 and P-3, respectively.
  • Example 2-1 To the following components was added deionized water to make 1 liter. The mixture was then heated to a temperature of from 30°C to 40°C with stirring for 1 hour. Thereafter, the solution was adjusted with 10 ml/1 of KOH to pH 9, and then filtered through a microfilter having an average pore diameter of 0.25 ⁇ m under reduced pressure to prepare a light magenta ink solution.
  • Magenta dye (a-36) ⁇ 8.2 g/L Diethylene glycol 43 g/L Urea 4 g L Glycerin 124 g L Triethylene glycol monobutyl ether 114 g/L 2-Pyrrolidone 3 g/L, Triethanolamine 3 g/L Benzotriazole 0.02 g ⁇ L.
  • the kind of dyes and additives were changed to prepare a magenta ink, a light cyan ink, a cyan ink, a yellow ink, a dark yellow ink and a black ink from which an ink set 101 set forth in Table 2-1 was then prepared.
  • Table 2-1 [Table 2-1]
  • Ink sets 102 to 107 were then prepared in the same manner as the ink set 101 except that the surface active agent, the water-miscible organic solvent and the dye were changed as set forth in Table 2-2.
  • the cartridge was mounted on the printer. The ejection of ink from all the nozzles was then confirmed. Thereafter, the nozzles were allowed to stand with their cap removed for 3 days. The nozzle check pattern was then printed. The number of times of cleaning required until no ejection was observed on the nozzle check pattern thus printed was then counted.
  • a solid gray print image sample was prepared. The sample thus prepared was then evaluated as follows. The image density Ci ofthe image which had been just printed on the sample was measured using X-rite 310. The image was inadiated with xenon light (85,000 lux) for 7 days, and then again measured for image density Cf to determine percent remaining of dye (Cf/Ci x 100). The percent remaining of dye was evaluated at three initial reflection density points of 1, 1.5 and 2. Those showing a percent dye remaining of 85% or more at any density point were ranked A, those showing a percent dye remaining of less than 85% at two of these density points were ranked B, and those showing a percent dye remaining of less than 85% at all the density points were ranked C.
  • the sample was allowed to stand in a box having an ozone gas concentration predetermined to 5 ppm for 3 days.
  • the image density before and after aging in the presence of ozone gas was measured using a reflection densitometer (X-Rite 310TR) to determine percent dye remaining which was then evaluated.
  • the percent remaining of dye was evaluated at three initial reflection density points of 1, 1.5 and 2. Those showing a percent dye remaining of 80% or more at any density point were ranked A, those showing a percent dye remaining of less than 85% at two of these density points were ranked B, and those showing a percent dye remaining of less than 70% at all the density points were ranked C.
  • a neutral gray data comprising a white line having a width of 0.2 mm extending through the center of a 10 mm square prepared using an imaging software (Adobe Photoshop) was outputted to a color printer wliich then printed a gray image having a reflection density of 1.5 (neutral color according to CIE) using a plurality of color inks.
  • the density was measured using a microdensitometer.
  • the results ofthe evaluations (1) to (4) are set forth in Table 2-3. [Table 2-3]
  • Example 2-2 The inks prepared in Example 2-1 were each packed in the cartridge of a Type BJ-F850 inkjet printer (produced by Canon Inc.). Using this inkjet printer, an image was then printed on an in jet photographic gloss paper EX produced by Fuji Photo Film Co., Ltd. The image thus printed was then evaluated in the same manner as in Example 2-1.
  • Example 2-1 The results thus obtained were similar to that of Example 2-1. Similar effects were exerted also with PM photographic paper produced by EPSON CO., LTD. or PR101 (produced by Canon Inc.).
  • an ink set for inkjet recording in the form of aqueous ink advantageous from the standpoint of handleability, odor, safety, etc. can be provided which exhibits a high ejection stability and can provide an image having an excellent weather resistance.
  • an inkjet recording method can be provided which is little subject to image bleeding even under high humidity conditions.
  • the invention can provide a recording method (preferably inkjet recording method) which exhibits a high ejection stability and gives an image having an excellent hue and little bleeding and thus can be expected to be widely spread for office use.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Ink Jet Recording Methods And Recording Media Thereof (AREA)
  • Inks, Pencil-Leads, Or Crayons (AREA)

Abstract

L'invention concerne un procédé d'impression à jet d'encre consistant à imprimer, sur une matière de réception d'images, une encre qui renferme un colorant anionique et de l'eau ou un solvant organique soluble dans l'eau, en fonction de données d'image afin de former une image, ledit colorant contenant au moins trois groupes fonctionnels de liaison à l'hydrogène. Un procédé d'impression consiste à éjecter, sur une matière d'impression, des gouttes d'encre au moyen d'au moins deux encres de couleur, le jaune et le magenta, qui renferment respectivement un colorant. Cette matière d'impression comporte un support et une couche de réception d'encre située sur le support. L'éjection s'effectue, selon un signal d'impression, de manière à imprimer une image sur la matière d'impression, le pourcentage de bavure de l'image imprimée étant au maximum de 30 %.
PCT/JP2004/019830 2004-01-08 2004-12-28 Procede d'impression WO2005066289A1 (fr)

Applications Claiming Priority (4)

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JP2004002755 2004-01-08
JP2004-002755 2004-01-08
JP2004-031954 2004-02-09
JP2004031954 2004-02-09

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8647425B2 (en) 2009-10-07 2014-02-11 Fujifilm Imaging Colorants Limited Azaphthalocyanines and their use in printing

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0948937A (ja) * 1995-08-08 1997-02-18 Fuji Photo Film Co Ltd 水性インクジェット記録用記録液
JPH1095942A (ja) * 1996-09-25 1998-04-14 Fuji Photo Film Co Ltd 水性インクジェット記録用記録液
JP2003213167A (ja) * 2002-01-22 2003-07-30 Fuji Photo Film Co Ltd 水溶性フタロシアニン化合物を含むインク、インクジェット用インク、インクジェット記録方法、及び着色画像材料のオゾンガス褪色改良方法
JP2003292850A (ja) * 2002-04-04 2003-10-15 Fuji Photo Film Co Ltd インクジェット記録用インク及びインクジェット記録方法
JP2003300380A (ja) * 2002-04-09 2003-10-21 Fuji Photo Film Co Ltd インクジェット記録方法
JP2003320747A (ja) * 2002-05-02 2003-11-11 Fuji Photo Film Co Ltd インクジェット記録用シート
JP2003321630A (ja) * 2002-04-30 2003-11-14 Fuji Photo Film Co Ltd インク組成物

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0948937A (ja) * 1995-08-08 1997-02-18 Fuji Photo Film Co Ltd 水性インクジェット記録用記録液
JPH1095942A (ja) * 1996-09-25 1998-04-14 Fuji Photo Film Co Ltd 水性インクジェット記録用記録液
JP2003213167A (ja) * 2002-01-22 2003-07-30 Fuji Photo Film Co Ltd 水溶性フタロシアニン化合物を含むインク、インクジェット用インク、インクジェット記録方法、及び着色画像材料のオゾンガス褪色改良方法
JP2003292850A (ja) * 2002-04-04 2003-10-15 Fuji Photo Film Co Ltd インクジェット記録用インク及びインクジェット記録方法
JP2003300380A (ja) * 2002-04-09 2003-10-21 Fuji Photo Film Co Ltd インクジェット記録方法
JP2003321630A (ja) * 2002-04-30 2003-11-14 Fuji Photo Film Co Ltd インク組成物
JP2003320747A (ja) * 2002-05-02 2003-11-11 Fuji Photo Film Co Ltd インクジェット記録用シート

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8647425B2 (en) 2009-10-07 2014-02-11 Fujifilm Imaging Colorants Limited Azaphthalocyanines and their use in printing

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