Source: http://www.google.com/patents/US7390083?dq=6004266
Timestamp: 2015-07-30 05:36:00
Document Index: 350613551

Matched Legal Cases: ['Application No. 2002', 'Application No. 2001', 'Application No. 2001', 'Application No. 2002', 'Application No. 2002', 'Application No. 2002', 'Application No. 2001', 'Application No. 2001']

Patent US7390083 - Ink-jet recording ink and method of ink-jet recording - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsAn inkjet recording ink including an aqueous medium having dissolved or dispersed therein a dye having a specific property or structure, and containing at least one antiseptic is provided, which can ensure excellent ejection stability and color hue even after long-term aging of the ink and exhibit excellent...http://www.google.com/patents/US7390083?utm_source=gb-gplus-sharePatent US7390083 - Ink-jet recording ink and method of ink-jet recordingAdvanced Patent SearchPublication numberUS7390083 B2Publication typeGrantApplication numberUS 10/504,029PCT numberPCT/JP2003/001127Publication dateJun 24, 2008Filing dateFeb 4, 2003Priority dateFeb 8, 2002Fee statusPaidAlso published asCN1300265C, CN1630691A, DE60334283D1, EP1473333A1, EP1473333A4, EP1473333B1, US20050117006, WO2003066753A1Publication number10504029, 504029, PCT/2003/1127, PCT/JP/2003/001127, PCT/JP/2003/01127, PCT/JP/3/001127, PCT/JP/3/01127, PCT/JP2003/001127, PCT/JP2003/01127, PCT/JP2003001127, PCT/JP200301127, PCT/JP3/001127, PCT/JP3/01127, PCT/JP3001127, PCT/JP301127, US 7390083 B2, US 7390083B2, US-B2-7390083, US7390083 B2, US7390083B2InventorsToshiki TaguchiOriginal AssigneeFujifilm CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (22), Non-Patent Citations (1), Classifications (13), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetInk-jet recording ink and method of ink-jet recording
US 7390083 B2Abstract
An inkjet recording ink including an aqueous medium having dissolved or dispersed therein a dye having a specific property or structure, and containing at least one antiseptic is provided, which can ensure excellent ejection stability and color hue even after long-term aging of the ink and exhibit excellent weather resistance.
1. An inkjet recording ink comprising an aqueous medium and a phthalocyanine dye dissolved in said aqueous medium, wherein said phthalocyanine dye is a water-soluble dye having an oxidation potential nobler than 1.0 V (vs SCE) and wherein said ink contains two or more different antiseptics,
Z represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R1 and R2 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, provided that when a plurality of Zs are present, these may be same or different;
Y1, Y2, Y3 and Y4 each independently represents a monovalent substituent;
provided that when a plurality of X1s, X2s, X3s, X4s, Y1s, Y2s, Y3s or Y4s are present, these may be same or different;
a1 to a4 and b1 to b4 represent a number of substituents X1 to X4 and Y1 to Y4, respectively, a1 to a4 each independently represents an integer of 0 to 4 but all are not 0 at the same time, and b1 to b4 each independently represents an integer of 0 to 4; and
M represents a hydrogen atom, a metal atom or an oxide thereof, hydroxide or halide thereof.
2. The inkjet recording ink as claimed in claim 1, wherein an ozone discoloration rate constant of recorded image is 5.0�10−2 [hour−1] or less when said inkjet recording ink is used for a recording of an image.
3. The inkjet recording ink as claimed in claim 1, wherein a monochromatic moiety of an image printed by using said inkjet recording ink to give a cyan reflection density of 0.9 to 1.1 in a Status A filter has a coloring matter residual ratio (density after discoloration/initial density�100) of 60% or more after storage of said printed image in an ozone environment of 5 ppm for 24 hours.
4. The inkj et recording ink as claimed in claim 1, wherein after storage of the image printed by using said inkjet recording ink to give a cyan reflection density of 0.9 to 1.1 in a Status A filter in an ozone environment of 5 ppm for 24 hours, an amount of Cu ion flowed out from said ink into water is 20% or less of all dyes.
5. The inkjet recording ink as claimed in claim 1, wherein said phthalocyanine dye is a water-soluble dye having an electron-withdrawing group at a β-position of a benzene ring of said phthalocyanine.
6. The inkjet recording ink as claimed in claim 1, wherein said phthalocyanine dye is a water-soluble phthalocyanine dye produced by a process not passing through sulfonation of an unsubstituted phthalocyanine.
7. The inkjet recording ink as claimed in claim 1, wherein the dye represented by formula (I) is a dye represented by the following formula (II):
wherein X11 to X14 and M1 have same meanings as X1 to X4 and M in formula (I), respectively
Y11 to Y18 each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cyano group, an alkoxy group, an amido group, a ureido group, a sulfonamido group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, a carboxyl group or a sulfo group;
provided that when a plurality of X11s, X12s, X13s, X14s, Y11s, Y12s, Y13s or Y14s are present, these may be the same or different; and
a11 to a14 represent a number of substituents X11 to X14 respectively and each independently represents an integer of 1 or 2.
8. The inkjet recording ink as claimed in claim 1, which contains an organic solvent having a boiling point of 150� C. or more.
9. An inkjet recording method comprising ejecting said inkjet recording ink claimed in claim 1 on an image-receiving material.
10. An inkjet recording method comprising ejecting ink droplets according to recording signals on an image-receiving material including a support having thereon an image-receiving layer containing a white inorganic pigment particle, thereby recording an image on said image-receiving material, wherein said ink droplet comprises said inkj et recording ink claimed in claim 1. Description
The present invention relates to an inkjet recording ink and a recording method using the ink, more specifically, the present invention relates to an inkjet recording ink capable of providing a recorded image with excellent preservability and high image quality such as color hue and color density, and ensuring excellent ink ejection stability.
The inkjet recording method includes a system of jetting out a liquid droplet by applying a pressure from a piezoelectric element, a system of jetting out a liquid droplet by generating a bubble in the ink under heat, a system of using an ultrasonic wave, and a system of jetting out a liquid droplet by suction using an electrostatic force. The inkjet recording ink used therefor includes an aqueous ink, an oily ink and a solid (fusion-type) ink.
Among these inks, an aqueous ink is relatively superior to oily ink or solid (fusion-type) ink in view of production, handleability, odor, safety and the like and therefore, is predominating as the inkjet recording ink at present.
The coloring matter used in such an inkjet recording ink is required to have high solubility in a solvent (ink medium), enable high-density recording, provide good color hue, exhibit excellent fastness to light, heat, air, water and chemicals, ensure good fixing to an image-receiving material and less bleeding, give an ink having excellent storability, have high purity and no toxicity, and be available at a low cost.
However, it is very difficult to find out a coloring matter satisfying these requirements in a high level. Among these requirements, good color hue and excellent fastness are conflicting in many cases and regarding the coloring material for magenta or cyan ink, a coloring matter satisfying the above-described requirements, particularly a coloring matter satisfying both good magenta or cyan color hue and light fastness high enough to withstand the oxidative atmosphere, can be hardly obtained.
Accordingly, although various dyes and pigments for use in inkjet recording have been already proposed and are actually used, a coloring matter satisfying all of the requirements described above is not yet found out at present.
Conventionally well-known dyes and pigments having a color index (C.I.) number can hardly satisfy both color hue and fastness required of the inkjet recording ink.
As for the dye capable of improving the fastness, azo dyes derived from an aromatic amine and a 5-membered heterocyclic amine have been proposed in Patent Document 1. However, these dyes have a problem of bad color reproducibility due to undesirable color hue present in the yellow and cyan regions.
Patent Documents 2 and 3 are disclosing an inkjet recording ink with an attempt to satisfy both color hue and light fastness. However, in use as a water-soluble ink, the coloring matters used in these patent publications are insufficient in the solubility in water. Also, when the coloring matters described in these patent publications are used as a water-soluble ink for inkjet recording, there arises a problem in the fastness to humidity and heat.
It has been also found that when an image is recorded on an inkjet special glossy paper for photographic image quality and put on a wall in a room, the image sometimes exhibits extremely bad preservability. The present inventors assume that this phenomenon is ascribable to some oxidative gas in air, such as ozone. This phenomenon scarcely occurs when the air flow is shut out, for example, by putting the image in a glass-made frame, but in this case, use conditions are limited.
This phenomenon is outstanding particularly in the case of inkjet special glossy paper for photographic image quality and raises a large problem for current inkjet recording systems where one of important characteristic features is the photographic image quality.
Furthermore, the aqueous ink is found to readily putrefy and cause a problem that when the ink is aged for a long period of time, the ejection property is seriously worsened due to putrefaction. It is also found that when a single antiseptic is used, the tolerance of bacteria increases and the effect is disadvantageously less expressed.
List of Patent Documents as Related Art
JP-A-55-161856 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)
JP-T-11-504958 (the term “JP-T” as used herein means a “published Japanese translation of a PCT patent application”)
An object of the present invention is to provide an inkjet recording ink which ensures excellent ejection stability and color hue even after long-term aging of the ink and exhibits excellent weather resistance, and a recording method using the ink.
The objects of the present invention can be attained by the techniques described in the following 1 to 19.
1. An inkjet recording ink comprising an aqueous medium having dissolved or dispersed therein a dye, wherein the dye is a water-soluble dye having an oxidation potential nobler than 1.0 V (vs SCE) and at least one antiseptic is contained in the ink.
2. The inkjet recording ink as described in 1 above, which is an inkjet recording ink comprising an aqueous medium having dissolved or dispersed therein a magenta dye selected from azo dyes, wherein the magenta dye is a dye having an absorption maximum in the spectral region of 500 to 580 nm in the aqueous medium and at the same time, having an oxidation potential nobler than 1.0 V (vs SCE) and at least one antiseptic is contained in the ink.
3. The inkjet recording ink as described in 1 or 2 above, wherein the azo dye has a chromophore represented by the formula: (heterocyclic ring A)-N═N-(heterocyclic ring B), provided that the heterocyclic ring A and the heterocyclic B may have the same structure.
4. The inkjet recording ink as described in any one of 1 to 3 above, wherein the azo dye is an azo dye in which an aromatic nitrogen-containing 6-membered heterocyclic ring is bonded as a coupling component directly to at least one side of the azo group.
5. The inkjet recording ink as described in any one of 1 to 4 above, wherein the azo dye is an azo dye having an aromatic ring amino group- or heterocyclic amino group-containing structure as an auxochrome.
6. The inkjet recording ink as described in any one of 1 to 15 above, wherein the azo dye is an azo dye having a steric structure.
7. The inkjet recording ink as described in any one of 1 to 6 above, wherein the azo dye is a dye represented by the following formula (1):
B1 and B2 each represents ═CR1— or —CR2═ or either one of B1 and B2 represents a nitrogen atom and the other represents ═CR1— or —CR2═;
8. The inkjet recording ink as described in any one of 1 to 7 above, wherein the ozone discoloration rate constant of recorded image is 5.0�10−2 [hour−1] or less.
9. The inkjet recording ink as described in 1 above, which is an inkjet recording ink comprising an aqueous medium having dissolved or dispersed therein a phthalocyanine dye, wherein the phthalocyanine dye is a water-soluble dye having an oxidation potential nobler than 1.0 and at least one antiseptic is contained in the ink.
10. The inkjet recording ink as described in 9 above, wherein after storage in an ozone environment of 5 ppm for 24 hours, the monochromatic moiety printed by using a single (cyan) color of the ink to give a cyan reflection density of 0.9 to 1.1 in a Status A filter has a coloring matter residual ratio (density after discoloration/initial density�100) of 60% or more.
11. The inkjet recording ink as described in 9 or 10 above, wherein after discoloration with ozone under the conditions of 10 above, the amount of Cu ion flowed out from the ink into water is 20% or less of all dyes.
12. The inkjet recording ink as described in any one of 9 to 11 above, wherein the phthalocyanine dye is a water-soluble dye having an electron-withdrawing group at the β-position of a benzene ring of the phthalocyanine.
13. The inkjet recording ink as described in any one of 9 to 12 above, wherein the phthalocyanine dye is a water-soluble phthalocyanine dye produced by a process not passing through sulfonation of an unsubstituted phthalocyanine.
14. The inkjet recording ink as described in 9 to 13 above, wherein the phthalocyanine dye is represented by the following formula (I):
wherein X1, X2, X3 and X4 each independently represents —SO—Z, —SO2—Z, —SO2NR1R2, a sulfo group, —CONR1R2 or —CO2R1;
Z represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and R1 and R2 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, provided that when a plurality of Zs are present, these may be the same or different;
provided that when a plurality of X1s, X2s, X3s, X4s, Y1s, Y2s, Y3s or Y4s are present, these may be the same or different;
a1 to a4 and b1 to b4 represent the number of substituents X1 to X4 and Y1 to Y4, respectively, a1 to a4 each independently represents an integer of 0 to 4 but all are not 0 at the same time, and b1 to b4 each independently represents an integer of 0 to 4; and
15. The inkjet recording ink as described in 14 above, wherein the dye represented by formula (I) is a dye represented by the following formula (II):
16. The inkjet recording ink as described in any one of 1 to 15 above, which contains two or more different antiseptics.
17. The inkjet recording ink as described in any one of 1 to 16 above, which contains an organic solvent having a boiling point of 150� C. or more.
18. An inkjet recording method comprising using the inkjet recording ink described in 1 to 17 above.
19. An inkjet recording method comprising ejecting ink droplets according to recording signals on an image-receiving material comprising a support having thereon an image-receiving layer containing a white inorganic pigment particle, thereby recording an image on the image-receiving material, wherein the ink droplet comprises the inkjet recording ink described in 1 to 17 above.
As a result of intensive investigations on the inkjet recording ink, the present inventors have found that the properties required of the dye are 1) to give a good color hue and be free of change in the color hue (solvate), 2) to exhibit excellent fastness (to light, ozone, NOx, solvent, oil and water), 3) to be safe (not carcinogenic by AMES, not irritating to skin and easily degradable), 4) to be inexpensive, 5) to have high ε, 6) to be highly soluble, and 7) to have strong fixing property to a medium.
The properties required of the image is 1) to be clear without blurring, discoloration and beading, 2) to have scratch resistance, 3) to have high and uniform gloss, 4) to have good image preservability and excellent balance in discoloration, 5) to be quickly dried, 6) to be printed at a high speed, and 7) to have no image density dependency in the discoloration ratio.
In order to satisfy the objective properties of the present invention, the image recording is performed by using a dye having properties specified in 1. to 18. above for the magenta ink. Accordingly, these properties of the magenta dye are described below.
In the magenta ink used for the inkjet recording ink of the present invention, a magenta dye selected from azo dyes is dissolved or dispersed in an aqueous medium and this dye is fundamentally characterized in that the absorption maximum in the aqueous medium is present in the spectral region of 500 to 580 nm and the oxidation potential is nobler than 1.0 V (vs SCE).
The second preferred structural feature of the azo dye is that an aromatic nitrogen-containing 6-membered heterocyclic ring is bonded as a coupling component directly to at least one side of the azo group. Specific examples thereof are described in 2001-110457.
The fourth preferred structural feature is that the dye has a steric structure. This is specifically described in Japanese Patent Application No. 2002-12015.
Among these preferred structural features of the azo dye, the dye most preferred for achieving the objects of the present invention is a dye represented by the following formula (1):
B1 and B2 each represents ═CR1— or —CR2═ or either one of B1 and B2 represents a nitrogen atom and the other represents ═CR1— or —CR 2═;
In formula (1), A represents a 5-membered heterocyclic group. Examples of the heteroatom of the heterocyclic ring include N, O and S. A is preferably a nitrogen-containing 5-membered heterocyclic ring and the heterocyclic ring may be condensed with an aliphatic ring, an aromatic ring or another heterocyclic ring. Preferred examples of the heterocyclic ring represented by A include a pyrazole ring, an imidazole ring, a thiazole ring, an isothiazole ring, a thiadiazole ring, a benzothiazole ring, a benzoxazole ring and a benzisothiazole ring. Each heterocyclic group may further have a substituent. Among these rings, more preferred are a pyrazole ring, an imidazole ring, an isothiazole ring, a thiadiazole ring and a benzothiazole ring represented by the following formulae (a) to (f):
In formula (1), B1 and B2 each represents ═CR1— or —CR2═ or either one of B1 and B2 represents a nitrogen atom and the other represents ═CR1— or —CR2═. B1 and B2 each preferably represents ═CR1— or —CR2═.
R5 sand R6 each independently represents a hydrogen atom or a substituent, the substituent is an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group or a sulfamoyl group, and the hydrogen atom of each substituent may be substituted.
In the case where the dye of the present invention is a water-soluble dye, the dye preferably further has an ionic hydrophilic group as a substituent on any position of A, R1, R2, R5, R6 and G. Examples of the ionic hydrophilic group as a substituent include a sulfo group, a carboxyl group, a phosphono group and a quaternary ammonium group. Among these ionic hydrophilic groups, preferred are a carboxyl group, a phosphono group and a sulfo group, more preferred are a carboxyl group and a sulfo group. The carboxyl group, the phosphono group and the sulfo group each may be in a salt state and examples of the counter ion for forming the salt include ammonium ion, alkali metal ions (e.g., lithium ion, sodium ion, potassium ion) and organic cations (e.g., tetramethylammonium ion, tetramethylguanidium ion, tetramethylphosphonium).
The aliphatic group means an alkyl group, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an alkynyl group, a substituted alkynyl group, an aralkyl group and a substituted aralkyl group. The “substituted” used for a “substituted alkyl group” and the like in the present invention means that the hydrogen atom present in an “alkyl group” or the like is substituted, for example, by a substituent described above for G, R1 and R2.
The aliphatic group may be branched 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 in the aralkyl group and in the substituted aralkyl group is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. Examples of the aliphatic group include a methyl group, an ethyl group, a butyl group, an isopropyl group, a tert-butyl group, a hydroxyethyl group, a methoxyethyl group, a cyanoethyl group, a trifluoromethyl group, a 3-sulfopropyl group, a 4-sulfobutyl group, a cyclohexyl group, a benzyl group, a 2-phenethyl group, a vinyl group and an allyl group.
The alkoxycarbonyloxy group includes a substituted alkoxycarbonyloxy group. The alkoxycarbonyloxy group is preferably an alkoxycarbonyloxy group having from 2 to 20 carbon atoms. Examples of the alkoxycarbonyloxy group include a methoxycarbonyloxy group and an isopropoxy-carbonyloxy group.
The alkylsulfonylamino group and the arylsulfonylamino group include a substituted alkylsulfonylamino group and a substituted arylsulfonylamino group, respectively. The alkylsulfonylamino group and the arylsulfonylamino group are preferably an alkylsulfonylamino group having from 1 to 20 carbon atoms and an arylsulfonylamino group having from 1 to 20 carbon atoms, respectively. Examples of the substituent of the substituted alkylsulfonylamino group and substituted arylsulfonylamino group include an ionic hydrophilic group. Examples of the alkylsulfonylamino group and arylsulfonylamino group include a methylsufonylamino group, an N-phenyl-methylsulfonylamino group, a phenylsulfonylamino group and a 3-carboxyphenyl-sulfonylamino group.
In formula (1a), R1 R2 R5 and R6 have the same meanings as in formula (1).
Z1 represents an electron-withdrawing group having a Hammett's substituent constant σp value of 0.20 or more. Z1 is preferably an electron-withdrawing group having a σp value of 0.30 or more, more preferably 0.45 or more, still more preferably 0.60 to more, but the up value preferably does not exceed 1.0. Specific preferred examples of this substituent include electron-withdrawing substituents described later. Among those, preferred are an acyl group having from 2 to 20 carbon atoms, an alkyloxycarbonyl group having from 2 to 20 carbon atoms, a nitro group, a cyano group, an alkylsulfonyl group having from 1 to 20 carbon atoms, an arylsulfonyl group having from 6 to 20 carbon atoms, a carbamoyl group having from 1 to 20 carbon atoms and a halogenated alkyl group having from 1 to 20 carbon atoms, more preferred are a cyano group, an alkylsulfonyl group having from 1 to 20 carbon atoms and an arylsulfonyl group having from 6 to 20 carbon atoms, and most preferred is a cyano group.
Here, the Hammett's substituent constant σp value used in the present invention is described. The Hammett's rule is an empirical rule advocated by L. P. Hammett in 1935 so as to quantitatively discuss the effect of substituent on the reaction or equilibrium of benzene derivatives and its propriety is widely admitted at present. The substituent constant determined by the Hammett's rule includes a σp value and a σm value and these values can be found in a large number of general publications but these are described in detail, for example, in J. A. Dean (compiler), Lange's Handbook of Chemistry, 12th ed., McGraw-Hill (1979), and Kagakuno Ryoiki (Chemistry Region), special number, No. 122, pp. 96-103, Nankodo (1979). In the present invention, each substituent is limited or described by using the Hammett's substituent constant σp but this does not mean that the substituent is limited only to those having a known value which can be found in the above-described publications. Needless to say, the substituent includes substituents of which σp value is not known in publications but when measured based on the Hammett's rule, falls within the range specified. Furthermore, although formula (1a) of the present invention includes those which are not a benzene derivative, the σp value is used as a measure for showing the electron effect of the substituent irrespective of the substitution site. In the present invention, the σp value is used in such a meaning.
B1 and B2 each is preferably ═CR1— or —CR 2═, and R1 and R2 each is preferably a hydrogen atom, an alkyl group, a halogen atom, a cyano group, a carbamoyl group, a carboxyl group, a hydroxyl group, an alkoxy group or an alkoxycarbonyl group, more preferably a hydrogen atom, an alkyl group, a carboxyl group, a cyano group or a carbamoyl group.
SO2CH3 The magenta dye having an azo group for use in the present invention has an oxidation potential, in an aqueous medium for ink, nobler than 1.0 V vs SCE, preferably nobler than 1.1 V vs SCE, more preferably nobler than 1.2 V vs SCE. The potential can be elevated by selecting the preferred structural features described above, more specifically, by selecting a dye structure of a type having a chromophore represented by (heterocyclic ring A)-N═N-(heterocyclic ring B), selecting an azo dye in which an aromatic nitrogen-containing 6-membered heterocyclic ring is bonded as a coupling component directly to at least one side of the azo group, and selecting an azo dye having an aromatic ring amino group- or heterocyclic amino group-containing structure as an auxochrome, and furthermore by removing α hydrogen of the azo dye. In particular, the dye of formula (1) expresses a noble potential. This is specifically described in Japanese Patent Application No. 2001-254878.
The oxidation potential as used herein can be measured by various measuring methods such as polarography in which a dropping mercury electrode is used, cyclic voltammetry method (CV), rotating ring-disk electrode method and comb electrode method. The oxidation potential is specifically measured as follows. A test sample is dissolved to a concentration of 1�10−4 to 1�10−6 mol�dm−3 in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate and the oxidation potential is measured as a value to SCE (standard saturated calomel electrode) by using the above-described method. The supporting electrolyte and solvent used can be appropriately selected according to the oxidation potential or solubility of the test sample. The supporting electrolyte and solvent which can be used are described in Akira Fujishima et al., Denkikagaku Sokutei Ho (Electrochemical Measuring Method), pp. 101-118, Gihodo Shuppan Sha (1984).
The oxidation potential value sometimes deviates on the order of several tens of millivolt due to the effect of, for example, liquid junction potential or liquid resistance of sample solution, but the reproducibility of measured potential value can be guaranteed by the calibration using a standard sample (for example, hydroquinone) and the same measured value can be obtained by any of those potential measuring methods.
Another basis for the oxidation resistance of the azo dye having an oxidation potential nobler than 1.0 V vs SCE is an enforced discoloration rate constant for ozone gas. The azo dye preferably has an enforced discoloration rate constant of 5.0�10−2 [hour−1] or less, more preferably 3.0�10−2 [hour−1] or less, still more preferably 1.5�10−2 [hour−1] or less.
The enforced discoloration rate constant for ozone gas is determined as follows. An image is printed on a reflective image-receiving medium by using only the ink concerned and the colored region having a color in the main spectral absorption region of the ink and having a reflection density of 0.90 to 1.10 as measured through a Status A filter is selected as the initial density point. This initial density is defined as the starting density (=100%). Then, this image is discolored by using an ozone discoloration tester capable of always keeping an ozone concentration of 5 mg/L, the time period until the density becomes 80% of the initial density is measured, a reciprocal [hour−1] of this time period is determined and on the assumption that the relationship between the discoloration density and the time period follows the rate equation of first-order reaction, the value determined is used as the discoloration reaction rate constant. Accordingly, the discoloration rate constant obtained is a discoloration rate constant in the colored region of an image printed by the ink, but in the present invention, this vale is used as the discoloration rate constant of the ink.
In the test chamber for the measurement of enforced discoloration rate constant for ozone gas, an ozone generator (for example, in a high-voltage discharge system of applying an a.c. voltage to dry air) capable of constantly maintaining an internal ozone gas concentration of 5-mg/L is provided and the exposure temperature is adjusted to 25� C.
This enforced discoloration rate constant is an index for showing the susceptibility to oxidation by oxidative atmosphere in the environment, such as photochemical smog, exhaust gas of automobiles, organic vapor from painted furniture surface or carpet, or gas generated from the frame interior in a bright room, and this is an index using ozone gas as a representative of such oxidative atmosphere.
The color hue of the magenta ink is described below. The magenta ink preferably has λmax of 500 to 580 nm in view of color hue, more preferably a small half-value width in the long-wave and short-wave sides of the maximum absorption wavelength, namely, sharp absorption. This is specifically described in JP-A-2002-309133. The sharp absorption can be also realized by introducing a methyl group into the α position.
[Phthalocyanine Dye]
The properties required of the inkjet recording ink is to be excellent in both light fastness and ozone resistance and small in the change of color hue and surface state (less generation of bronze and less precipitation of dye). As for the light fastness (OD1.0), the light fastness with a triacetylcellulose (TAC) filter on Epson PM Photographic Image-Receiving Paper by Xe of 1.1 W/m (intermittent conditions) is preferably 90% or more in terms of the residual color ratio for 3 days. Also, the coloring matter residual ratio for 14 days is preferably 85% or more.
As for the ozone resistance, after storage in an ozone environment of 5 ppm for 24 hours, the monochromatic moiety printed by using a single (cyan) color of the ink to give a cyan reflection density of 0.9 to 1.1 in a Status A filter has a coloring matter residual ratio (density after discoloration/initial density�100) of 60% or more. The ozone resistance is more preferably 70% or more, still more preferably 80% or more, in terms of the coloring matter residual ratio for one day. Also, the coloring matter residual ratio for 5 days is preferably 25% or more, more preferably 40% or more, still more preferably 50% or more. Samples varied in the coated amount of dye are prepared by GTC and the amount of Cu element contained in the dye is measured by a fluorescent X ray.
The Cu ion is present in the form of a phthalate as a result of decomposition of the phthalocyanine dye. The amount of Cu salt present in an actual print is preferably 10 mg/m2 or less in terms of Cu ion. The amount of Cu flowed out from the print is determined by forming an entire cyan solid image having a Cu salt amount of 20 mg/m2 or less in terms of Cu ion, discoloring this image with ozone and analyzing the amount of ion flowed out into water. Incidentally, all Cu compounds are trapped by the image-receiving material before the discoloration. The amount of Cu ion flowed out into water is preferably 20% or less of all dyes.
It has been found in the present invention that a phthalocyanine dye having such properties can be obtained, for example, by 1) elevating the oxidation potential, 2) enhancing the aggregating property, 3) introducing an aggregation accelerating group, intensifying the hydrogen bond at the time of λ-λ stacking, or 4) not incorporating a substituent at the α-position, that is, facilitating the stacking.
Conventional phthalocyanine dyes used for the inkjet ink are derived from an unsubstituted phthalocyanine through sulfonation and these are a mixture which cannot be specified in the number and positions of substituents. On the other hand, the dye for use in the inkjet recording ink of the present invention is a phthalocyanine dye which can be specified in the number and positions of substituents. The first structural feature is that the dye is a water-soluble phthalocyanine dye obtained by not passing through sulfonation of an unsubstituted phthalocyanine. The second structural feature is that the dye has an electron-withdrawing group at the β-position of a benzene ring of phthalocyanine, preferably at the β-position of all benzene rings. Specific examples of useful dyes include those where a sulfonyl group is substituted (see, Japanese Patent Application Nos. 2001-47013 and 2001-190214), a sulfamoyl group in general is substituted (see, Japanese Patent Application Nos. 2001-24352 and 2001-189982), a heterocyclic sulfamoyl group is substituted (see, Japanese Patent Application Nos. 2001-96610 and 2001-190216), a heterocyclic sulfonyl group is substituted (see, Japanese Patent Application Nos. 2001-76689 and 2001-190215), a specific sulfamoyl group is substituted (see, Japanese Patent Application No. 2001-57063), a carbonyl group is substituted (see, Japanese Patent Application No. 2002-012869), or the dye has a specific substituent for enhancing the solubility or ink stability or preventing the bronze phenomenon, such as asymmetric carbon (see, Japanese Patent Application No. 2002-012868) or Li salt form (see, Japanese Patent Application No. 2002-012864).
The first physical feature of the phthalocyanine dye for use in the inkjet recording ink of the present invention is to have a high oxidation potential. The oxidation potential is preferably nobler than 1.0 V, more preferably nobler than 1.1 V, and most preferably nobler than 1.2 V. The second physical feature is to have a strong aggregating property. Specific examples of the dye having this property include those where the aggregation of oil-soluble dyes is specified (see, Japanese Patent Application No. 2001-64413) or the aggregation of water-soluble dyes is specified (see, Japanese Patent Application No. 2001-117350).
With respect to the relationship between the number of aggregating groups and the performance (light absorbance of ink), when an aggregating group is introduced, reduction of light absorbance or shifting of λmax to the shorter wave is liable to occur even in a dilute solution. With respect to the relationship between the number of aggregating groups and the performance (reflection OD on Epson PM920 Image-Receiving Paper), as the number of aggregating groups increases, the reflection OD with the same ion intensity more decreases. That is, the aggregation is considered to proceed on the image-receiving paper. With respect to the relationship between the number of aggregating groups and the performance (ozone resistance/light fastness), as the number of aggregating groups increases, the ozone resistance is more enhanced. A dye having a large number of aggregating groups tends to be enhanced also in the light fastness. In order to impart the ozone resistance, the above-described substituent X (which represents X1, X2, X3, X4 or the like) must be present. The reflection OD and the fastness are in the trade-off relationship and therefore, it is necessary to enhance the light fastness without weakening the aggregation.
2) a cyan ink where after storage in an ozone environment of 5 ppm for 24 hours, the monochromatic moiety printed by using a single (cyan) color of the ink to give a cyan reflection density of 0.9 to 1.1 in a Status A filter has a coloring matter residual ratio (density after discoloration/initial density�100) of 60% (preferably 80%) or more;
3) a cyan ink where after discoloration with ozone under the conditions of 2) above, the amount of Cu ion flowed out into water is 20% or less of all dyes; and
The phthalocyanine dye contained in the inkjet recording ink of the present invention is preferably a water-soluble dye having an oxidation potential nobler than 1.0, more preferably a dye having ozone gas fastness satisfying the above-described conditions, still more preferably a phthalocyanine dye represented by formula (I).
The phthalocyanine dye is a dye having fastness but this dye is known to be inferior in the fastness to ozone gas when used as a coloring matter for inkjet recording.
In the present invention, an electron-withdrawing group is introduced into the phthalocyanine skeleton to render the oxidation potential nobler than 1.0 V (vs SCE) and thereby reduce the reactivity with ozone which is an electrophilic agent. A nobler oxidation potential is more preferred and the oxidation potential is more preferably nobler than 1.1 V (vs SCE) and most preferably nobler than 1.2 V (vs SCE).
More specifically, a test sample is dissolved to a concentration of 1�10−4 to 1�10−6 mol/liter in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate and the oxidation potential is measured as a value to SCE (saturated calomel electrode) by using a cyclic voltammetry. This value sometimes deviates on the order of several tens of millivolt due to the effect of, for example, liquid junction potential or liquid resistance of sample solution, but the reproducibility of potential can be guaranteed by adding a standard sample (for example, hydroquinone).
The Eox (oxidation potential) value indicates the transferability of an electron from the sample to the electrode and as the value is larger (the oxidation potential is nobler), the electron is less transferable from the sample to the electrode, in other words, the oxidation less occurs. As for the relationship with the structure of compound, the oxidation potential becomes nobler when an electron-withdrawing group is introduced, and becomes baser when an electron-donating group is introduced. In the present invention, the oxidation potential is preferably rendered nobler by introducing an electron-withdrawing group into the phthalocyanine skeleton so as to reduce the reactivity with ozone which is an electrophilic agent. When the Hammett's substituent constant σp value as a measure for the electron-withdrawing property or electron-donating property of substituent is used, the oxidation potential can be rendered nobler by introducing a substituent having a large σp value, such as sulfinyl group, sulfonyl group and sulfamoyl group.
In formula (I), X1, X2, X3 and X4 each independently represents —SO—-Z, —SO2-z, —SO2NR1R2, a sulfo group, —CONR1R2 or —CO2R1. Among these substituents, preferred are —SO-Z, —SO2-Z, —SO2NR1R2 and —CONR1R2, more preferred are —SO2-Z and —SO2NR1R2, and most preferred is —SO2-Z. In the case where a1 to a4 showing the number of substituents each represents a number of 2 or more, a plurality of substituents X1, X2, X3 or X4 may be the same or different and each independently represents any one of the above-described groups. X1, X2, X3 and X4 may be completely the same substituents, may be substituents of the same kind but partially different as in the case, for example, where X1, X2, X3 and X4 all are —SO2-Z and Zs are different from each other, or may contain substituents different from each other, for example, —SO2-Z and —SO2NR1R2.
The substituted or unsubstituted alkenyl group represented by R1, R2 and Z is preferably an alkenyl group having from 2 to 30 carbon atoms, more preferably a branched alkenyl group because the solubility of dye and the stability of ink are improved, still more preferably an alkenyl group having an asymmetric carbon (use in the racemic form). Examples of the substituent include those described later as the substituent when Z, R1, R2, Y1 Y2, Y3 and Y4 can further have a substituent. In particular, a hydroxyl group, an ether group, an ester group, a cyano group, an amido group and a sulfonamido group are preferred because the aggregating property and fastness of dye are enhanced. Other than these, the alkenyl group may be substituted by a halogen atom or an ionic hydrophilic group.
The substituted or unsubstituted aryl group represented by R1, R2 and Z is preferably an aryl group having from 6 to 30 carbon atoms. Examples of the substituent include those described later as the substituent when Z. R1, R2, Y1, Y2, Y3 and Y4 can further have a substituent. In particular, an electron-withdrawing group is preferred because the dye can have a noble oxidation potential and can be improved in the fastness. Examples of the electron-withdrawing group include those having a positive Hammett's substituent constant σp value. Among these, preferred are a halogen atom, a heterocyclic group, a cyano group, a carboxyl group, an acylamino group, a sulfonamido group, a sulfamoyl group, a carbamoyl group, a sulfonyl group, an imido group, an acyl group, a sulfo group and a quaternary ammonium group, more preferred are a cyano group, a carboxyl group, a sulfamoyl group, a carbamoyl group, a sulfonyl group, an imido group, an acyl group, a sulfo group and a quaternary ammonium group.
The heterocyclic group represented by R1, R2 and Z is preferably a 5- or 6-membered ring and the ring may be further condensed. Also, the heterocyclic group may be an aromatic heterocyclic group or a non-aromatic heterocyclic group. Examples of the heterocyclic group represented by R1, R2 and Z are shown below in the form of a heterocyclic ring by omitting the substitution site. The substitution site is not limited and, for example, in the case of pyridine, the 2-position, 3-position and 4-position can be substituted. Examples include pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole, indole, furan, benzofuran, thiophene, benzothiophene, pyrazole, imidazole, benzimidazole, triazole, oxazole, benzoxazole, thiazole, benzothiazole, isothiazole, benzisothiazole, thiadiazole, isoxazole, benzisoxazole, pyrrolidine., piperidine, piperazine, imidazolidine and thiazoline. In particular, an aromatic heterocyclic group is preferred. Preferred examples thereof include, shown in the same manner as above, pyridine, pyrazine, pyrimidine, pyridazine, triazine, pyrazole, imidazole, benzimidazole, triazole, thiazole, benzothiazole, isothiazole, benzisothiazole and thiadiazole. These groups each may have a substituent and examples of the substituent include those described later as the substituent when Z, R1, R2, Y1, Y2, Y3 and Y4 can further have a substituent. Preferred substituents are the same as the above-described substituents of the aryl group and more preferred substituents are the same as the above-described more preferred substituents of the aryl group.
When Z, R1, R2, Y1, Y2, Y3 and Y4 each is a group which can further have a substituent, the group may further have a substituent described below.
Examples of the substituent include a linear or branched alkyl group having from 1 to 12 carbon atoms, a linear or branched aralkyl group having from 7 to 18 carbon atoms, a linear or branched alkenyl group having from 2 to 12 carbon atoms, a linear or branched alkynyl group having from 2 to 12 carbon atoms, a linear or branched cycloalkyl group having from 3 to 12 carbon atoms, a linear or branched cycloalkenyl group having from 3 to 12 carbon atoms (these groups each is preferably a group having a branched chain because the solubility of dye and the stability of ink are improved, more preferably a group having an asymmetric carbon; specific examples of the groups include methyl, ethyl, propyl, isopropyl, sec-butyl, tert-butyl, 2-ethylhexyl, 2-methylsulfonylethyl, 3-phenoxypropyl, trifluoromethyl and cyclopentyl), a halogen atom (e.g., chlorine, bromine), an aryl group (e.g., phenyl, 4-tert-butylphenyl, 2,4-di-tert-amylphenyl), a heterocyclic group (e.g., imidazolyl, pyrazolyl, triazolyl, 2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl), a cyano group, a hydroxyl group, a nitro group, a carboxy group, an amino group, an alkyloxy group (e.g., methoxy, ethoxy, 2-methoxyethoxy, 2-methanesulfonylethoxy), an aryloxy group (e.g., phenoxy, 2-methylphenoxy, 4-tert-butylphenoxy, 3-nitrophenoxy, 3-tert-butyloxycarbamoylphenoxy, 3-methoxycarbamoyl), an acylamino group (e.g., acetamido, benzamido, 4-(3-tert-butyl-4-hydroxyphenoxy)butanamido), an alkylamino group (e.g., methylamino, butylamino, diethylamino, methylbutylamino), an anilino group (e.g., phenylamino, 2-chloroanilino), a ureido group (e.g., phenylureido, methylureido, N,N-dibutylureido), a sulfamoylamino group (e.g., N,N-dipropylsulfamoylamino), an alkylthio group (e.g., methylthio, octylthio, 2-phenoxyethylthio), an arylthio group (e.g., phenylthio, 2-butoxy-5-tert-octylphenylthio, 2-oarboxyphenylthio), an alkyloxycarbonylamino group (e.g., methoxycarbonylamino), a sulfonamido group (e.g., methanesulfonamido, benzenesulfonamido, p-toluenesulfonamido), a carbamoyl group (e.g., N-ethylcarbamoyl, N,N-dibutylcarbamoyl), a sulfamoyl group (e.g., N-ethylsulfamoyl, N,N-dipropylsulfamoyl, N-phenylsulfamoyl), a sulfonyl group (e.g., methanesulfonyl, octanesulfonyl, benzenesulfonyl, toluenesulfonyl), an alkyloxycarbonyl group (e.g., methoxycarbonyl, butyloxycarbonyl), a heterocyclic oxy group (e.g., 1-phenyltetrazol-5-oxy, 2-tetrahydropyranyloxy), an azo group (e.g., phenylazo, 4-methoxyphenylazo, 4-pivaloylamino-phenylazo, 2-hydroxy-4-propanoylphenylazo), an acyloxy group (e.g., acetoxy), a carbamoyloxy group (e.g., N-methylcarbamoyloxy, N-phenylcarbamoyloxy), a silyloxy group (e.g., trimethylsilyloxy, dibutylmethylsilyloxy), an aryloxycarbonylamino group (e.g., phenoxycarbonylamino), an imido group (e.g., N-succinimido, N-phthalimido), a heterocyclic thio group (e.g., 2-benzothiazolylthio, 2,4-di-phenoxy-1,3,5-triazole-6-thio, 2-pyridylthio), a sulfinyl group (e.g., 3-phenoxypropylsulfinyl), a phosphonyl group (e.g., phenoxyphosphonyl, octyloxyphosphonyl, phenylphosphonyl), an aryloxycarbonyl group (e.g., phenoxycarbonyl), an acyl group (e.g., acetyl, 3-phenylpropanoyl, benzoyl), and an ionic hydrophilic group (e.g., carboxyl, sulfo, phosphono, quaternary ammonium).
a1 to a4 and b1 to b4 represent the number of substituents X1 to X4 and Y1 to Y4, respectively a1 to a4 each independently represents an integer of 0 to 4 but all are not 0 at the same time. b1 to b4 each independently represents an integer of 0 to 4. When a1, a2, a3, a4, b1, b2, b3 or b4 represents an integer of 2 or more, a plurality of X1s, X2s, X3s, X4s, Y1s, Y2s, Y3s or Y4s are present and these may be the same or different.
X11, X12, X13 and X14 may be completely the same substituents, may be substituents of the same kind but partially different as in the case, for example, where X11, X12, X13 and X14 all are —SO2-Z and Zs are different from each other, or may contain substituents different from each other, for example, —SO2-Z and —SO2NR1R2.
Y11 to Y18 each independently represents preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cyano group; an alkoxy group, an amido group, a ureido group, a sulfonamido group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, a carboxyl group or a sulfo group, more preferably a hydrogen atom, a halogen atom, a cyano group, a carboxyl group or a sulfo group, and most preferably a hydrogen atom.
As for the chemical structure of the phthalocyanine dye of the present invention, at least one electron-withdrawing group such as sulfinyl group, sulfonyl group and sulfamoyl group is preferably introduced into respective four benzene rings of phthalocyanine such that the total of σp values of the substituents in the entire phthalocyanine skeleton becomes 1.6 or more.
The Hammett's substituent constant σp value is briefly described here. The Hammett's rule is an empirical rule advocated by L. P. Hammett in 1935 so as to quantitatively discuss the effect of substituent on the reaction or equilibrium of benzene derivatives and its propriety is widely admitted at present. The substituent constant determined by the Hammett's rule includes a σp value and a σm value and these values can be found in a large number of general publications but these are described in detail, for example, in J. A. Dean (compiler), Lange's Handbook of Chemistry, 12th ed., McGraw-Hill (1979), and Kagakuno Ryoiki (Chemistry Region), special number, No. 122, pp. 96-103, Nankodo (1979).
Inevitably in view of the synthesis method, the phthalocyanine derivative represented by formula (I) is generally a mixture of analogues differing in the site where the substituents Xn (n=1 to 4) and Ym (m=1 to 4) are introduced and in the number of the substituents introduced. Accordingly, these analogue mixtures are statistically averaged and represented by a formula in many cases. In the present invention, it has been found that when these analogue mixtures are classified into the following three types, a specific mixture is particularly preferred. The phthalocyanine-base dye analogue mixtures represented by formulae (I) and (II) are defined by classifying these into the following three types based on the substitution site. Y11, Y12, Y13, Y14, Y15, Y16, Y17 and Y18 in formula (II) are designated as the 1-position, 4-position, 5-position, 8-position, 9-position, 12-position, 13-position and 16-position, respectively.
The phthalocyanine derivative for use in the present invention can be synthesized by combining the methods described or cited, for example, in Shirai and Kobayashi, Phthalocyanine-Kagaku to Kino-(Phthalocyanine-Chemistry and Function-), pp. 1-62, IPC, and C. C. Leznoff and A. B. P. Lever, Phthalocyanines—Properties and Applications, pp. 1-54, VCH, or methods analogous thereto.
As described above, for example, when many electron-withdrawing groups such as sulfamoyl group are introduced into the phthalocyanine nucleus, the oxidation potential becomes nobler and the ozone resistance is increased. However, according to the above-described synthesis method, a phthalocyanine dye where the number of electron-withdrawing groups introduced is small, namely, the oxidation potential is baser, is inevitably mingled. Therefore, in order to improve the ozone resistance, it is preferred to use a synthesis method where the production of a compound having a baser oxidation potential is suppressed.
That is, according to this synthesis method, a specific number of desired substituents can be introduced. Particularly, in the case of introducing a large number of electron-withdrawing groups so as to render the oxidation potential nobler as in the present invention, this synthesis method is very excellent as compared with the above-described method for synthesizing the phthalocyanine compound of formula (I).
In the present invention, it has been found very important for the improvement of fastness that in any substitution type, the oxidation potential is nobler than 1.0 V (vs SCE). The great effect thereof cannot be expected at all from the above-described known techniques. Furthermore, although the reason is not particularly known, there is a tendency that the β-position substitution type is apparently more excellent in the color hue, light fastness, ozone gas resistance and the like than the α,β-position mixed substitution type.
Specific examples (Compounds I-1 to I-12 and 101 to 190) of the phthalocyanine dyes represented by formulae (I) and (II) are set forth below, but the phthalocyanine dye for use in the present invention is not limited to the following examples.
—Cl,—H
In the following Tables, each introduction site of substituents (Xp1) and (Xp2) is in an irregular order within the β-position substitution type.
M-Pc(Xpl)m(Xp2)n Compound No.
The inkjet recording ink of the present invention (sometimes referred to as “the ink of the present invention”) is a magenta or cyan ink obtained by dissolving or dispersing at least one azo dye or phthalocyanine dye described above in an aqueous medium and preferably containing the azo dye or phthalocyanine dye in an amount of 0.2 to 20 mass %, more preferably from 0.5 to 15 mass %.
In the ink of the present invention, for adjusting the color tone, other dyes can be added in addition to the above-described specific azo or phthalocyanine dye. Also, for constituting an ink set for full color printing, a yellow color, a black ink and the like are used in combination with the ink of the present invention and in these inks, respective coloring matters are used. Furthermore, a magenta ink and a cyan ink other than those of the present invention can also be used. Examples of the coloring matter which can be used in combination include the followings.
Examples of the yellow coloring matter include aryl- or heteryl-azo dyes having a phenol, a naphthol, an aniline, a pyrazolone, a pyridone or an open chain-type active methylene compound as the coupling component; azomethine dyes having an open chain-type active methylene compound as the coupling component; methine dyes such as benzylidene dye and monomethine oxonol dye; and quinone-base dyes such as naphthoquinone dye and anthraquinone dye. Other examples of the coloring matter species include quinophthalone dye, nitro•nitroso dye, acridine dye and acridinone dye. These coloring matters may be a coloring matter which provides a yellow color for the first time when a part of the chromophore is dissociated. In this case, the counter cation may be an inorganic cation such as alkali metal and ammonium, an organic cation such as pyridinium and quaternary ammonium salt, or a polymer cation having such a cation in the partial structure.
Examples of the magenta coloring matter include aryl- or heteryl-azo dyes having a phenol, a naphthol or an aniline as the coupling component; azomethine dyes having a pyrazolone or a pyrazolotriazole as the coupling component; methine dyes such as arylidene dye, styryl dye, merocyanine dye and oxonol dye; carbonium dyes such as diphenylmethane dye, triphenylmethane dye and xanthene dye; quinone-base dyes such as naphthoquinone, anthraquinone and anthrapyridone; and condensed polycyclic dyes such as dioxazine dye. These coloring matters may be a coloring matter which provides a magenta color for the first time when a part of the chromophore is dissociated. In this case, the counter cation may be an inorganic cation such as alkali metal and ammonium, an organic cation such as pyridinium and quaternary ammonium salt, or a polymer cation having such a cation in the partial structure.
Examples of the cyan coloring matter include azomethine dyes such as indoaniline dye and indophenol dye; polymethine dyes such as cyanine dye, oxonol dye and merocyanine dye; carbonium dyes such as diphenylmethane dye, triphenylmethane dye and xanthene dye; phthalocyanine dyes; anthraquinone dyes; aryl- or heteryl-azo dyes having a phenol, a naphthol or an aniline as the coupling component; and indigo-thioindigo dyes. These coloring matters may be a coloring matter which provides a cyan color for the first time when a part of the chromophore is dissociated. In this case, the counter cation may be an inorganic cation such as alkali metal and ammonium, an organic cation such as pyridinium and quaternary ammonium salt, or a polymer cation having such a cation in the partial structure.
A black coloring matter such as polyazo dye can also be used.
Other examples of the water-soluble dye include a direct dye, an acid dye, a food color, a basic dye and a reactive dye. Preferred examples thereof include C.I. Direct Red 2, 4, 9, 23, 26, 31, 39, 62, 63, 72, 75, 76, 79, 80, 81, 83, 84, 89, 92, 95, 111, 173, 184, 207, 211, 212, 214, 218, 21, 223, 224, 225, 226, 227, 232, 233, 240, 241, 242, 243 and 247; C.I. Direct Violet 7, 9, 47, 48, 51, 66, 90, 93, 94, 95, 98, 100 and 101; C.I. direct Yellow 8, 9, 11, 12, 27, 28, 29, 33, 35, 39, 41, 44, 50, 53, 58, 59, 68, 86, 87, 93, 95, 96, 98, 100, 106, 108, 109, 110, 130, 132, 142, 144, 161 and 163; C.I. Direct Blue 1, 10, 15, 22, 25, 55, 67, 68, 71, 76, 77, 78, 80, 84, 86, 87, 90, 98, 106, 108, 109, 151, 156, 158, 159, 160, 168, 189, 192, 193, 194, 199, 200, 201, 202, 203, 207, 211, 213, 214, 218, 225, 229, 236, 237, 244, 248, 249, 251, 252, 264, 270, 280, 288, 289 and 291; C.I. Direct Black 9, 17, 19, 22, 32, 51, 56, 62, 69, 77, 80, 91, 94, 97, 108, 112, 113, 114, 117, 118, 121, 122, 125, 132, 146, 154, 166, 168, 173 and 199; C.I. Acid Red 35, 42, 52, 57, 62, 80, 82, 111, 114, 118, 119, 127, 128, 131, 143, 151, 154, 158, 249, 254, 257, 261, 263, 266, 289, 299, 301, 305, 336, 337, 361, 396 and 397; C.I. Acid Violet 5, 34, 43, 47, 48, 90, 103 and 126; C.I. Acid Yellow 17, 19, 23, 25, 39, 40, 42, 44, 49, 50, 61, 64, 76, 79, 110, 127, 135, 143, 151, 159, 169, 174, 190, 195, 196, 197, 199, 218, 219, 222 and 227; C.I. Acid Blue 9, 25, 40, 41, 62, 72, 76, 78, 80, 82, 92, 106, 112, 113, 120, 127:1, 129, 138, 143, 175, 181, 205, 207, 220, 221, 230, 232, 247, 258, 260, 264, 271, 277, 278, 279, 280, 288, 290 and 326; C.I. Acid Black 7, 24, 29, 48, 52:1 and 172; C.I. Reactive Red 3, 13, 17, 19, 21, 22, 23, 24, 29, 35, 37, 40, 41, 43, 45, 49 and 55; C.I. Reactive Violet 1, 3, 4, 5, 6, 7, 8, 9, 16, 17, 22, 23, 24, 26, 27, 33 and 34; C.I. Reactive Yellow 2, 3, 13, 14, 15, 17, 18, 23, 24, 25, 26, 27, 29, 35, 37, 41 and 42; C.I. Reactive Blue 2, 3, 5, 8, 10, 13, 14, 15, 17, 18, 19, 21, 25, 26, 27, 28, 29 and 38; C.I. Reactive Black 4, 5, 8, 14, 21, 23, 26, 31, 32 and 34; C.I. Basic Red 12, 13, 14, 15, 18, 22, 23, 24, 25, 27, 29, 35, 36, 38, 39, 45 and 46; C.I. Basic Violet 1, 2, 3, 7, 10, 15, 16, 20, 21, 25, 27, 28, 35, 37, 39, 40 and 48; C.I. Basic Yellow 1, 2, 4, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 39 and 40; C.I. Basic Blue 1, 3, 5, 7, 9, 22, 26, 41, 45, 46, 47, 54, 57, 60, 62, 65, 66, 69 and 71; and C.I. Basic Black 8.
The coloring matter containing the azo dye or phthalocyanine dye for use in the present invention is substantially water-soluble or water-dispersible. More specifically, the coloring matter containing respective dyes preferably has a solubility of 2 mass % or more, more preferably 5 mass % or more, in water at 20� C.
In the ink of the present invention and other inks combined therewith for providing an ink set, a pigment can also be used in combination.
As the pigment for use in the present invention, commercially available pigments and known pigments described in various publications can be used. Examples of the publication include Color Index, compiled by The Society of Dyers and Colourists, Kaitei Shin Han Ganryo Binran (Revised New Handbook of Pigments), compiled by Nippon Ganryo Gijutsu Kyokai (1989), Saishin Ganryo Oyo Gijutsu (Newest Pigment Application Technology), CMC Shuppan (1986), Insatsu Ink Gijutsu (Printing Ink Technique), CMC Shuppan (1984), and W. Herbst and K. Hunger, Industrial Organic Pigments, VCH Verlagsgesellschaft (1993). Specific examples of the pigment include organic pigments such as azo pigments (e.g., azo lake pigment, insoluble azo pigment, condensed azo pigment, chelate azo pigment), polycyclic pigments (e.g., phthalocyanine-base pigment, anthraquinone-base pigment, perylene-base or perynone-base pigment, indigo-base pigment, quinacridone-base pigment, dioxazine-base pigment, isoindolinone-base pigment, quinophthalone-base pigment, diketopyrrolopyrrole-base pigment), dyeing lake pigments (lake pigments of acidic or basic dye) and azine pigments, and inorganic pigments such as C.I. Pigment Yellow 34, 37, 42 and 53 which are a yellow pigment, C.I. Pigment Red 101 and 108 which are a red-type pigment, C.I. Pigment Blue 27, 29 and 17:1 which are a blue-type pigment, C.I. Pigment Black 7 and magnetite which are a black-type pigment, and C.I. Pigment White 4, 6, 18 and 21 which are a white-type pigment.
As the red to violet pigment, azo pigments (preferred examples thereof include C.I. 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 and 184, and among these, C.I. Pigment Red 57:1, 146 and 184 are more preferred), quinacridone-base pigments (preferred examples thereof include C.I. Pigment Red 122, 192, 202, 207 and 209 and C.I. Pigment Violet 19 and 42, and among these, C.I. Pigment Red 122 is more preferred), dyeing lake pigment-type triarylcarbonium pigments (preferred examples thereof include xanthene-base C.I.
Pigment Red 81:1 and C.I. Pigment Violet 1, 2, 3, 27 and 39), dioxazine-base pigments (for example, C.I. Pigment Violet 23 and 37), diketopyrrolopyrrole-base pigments (for example, C.I. Pigment Red 254), perylene pigments (for example, C.I. Pigment Violet 29), anthraquinone-base pigments (for example, C.I. Pigment Violet 5:1, 31 and 33) and thioindigo-base pigments (for example, C.I. Pigment Red 38 and 88) are preferred.
As the yellow pigment, azo pigments (preferred examples thereof include monoazo pigment-type C.I. Pigment Yellow 1, 3, 74 and 98, disazo pigment-type C.I. Pigment Yellow 12, 13, 14, 16, 17 and 83, synthetic azo-type C.I.
Pigment 93, 94, 95, 128 and 155, and benzimidazolone-type C.I. Pigment Yellow 120, 151, 154, 156 and 180, and among these, those not using a benzidine-base compound as a raw material are more preferred), isoindoline-isoindolinone-base pigments (preferred examples thereof include C.I. Pigment Yellow 109, 110, 137 and 139), quinophthalone pigments (preferred examples thereof include C.I. Pigment Yellow 138) and flavanthrone pigments (for example, C.I. Pigment Yellow 24) are preferred.
The above-described pigment which can be used in the present invention may be used as it is or may be subjected to a surface treatment. For the surface treatment, a method of coating the surface with resin or wax, a method of attaching a surfactant, and a method of binding a reactive substance (for example, a radical generated from a silane coupling agent, an epoxy compound, polyisocyanate or a diazonium salt) to the pigment surface may be used and these are described in the following publications and patents:
The ink of the present invention further comprises an antiseptic. The antiseptic as used in the present invention means a material having a function of preventing the generation or growth of microorganisms, particularly, bacteria and fungi.
As the antiseptic for use in the present invention various antiseptics can be used.
Examples thereof include heavy metal ion-containing inorganic antiseptics (e.g., silver ion-containing material) and salts. As for the organic antiseptic, various antiseptics can be used, such as quaternary ammonium salts (e.g., tetrabutylammonium chloride, cetylpyridinium chloride, benzyltrimethylammonium chloride), phenol derivatives (e.g., phenol, cresol, butylphenol, xylenol, bisphenol), phenoxy ether derivatives (e.g., phenoxyethanol), heterocyclic compounds (e.g., benzotriazole, Proxel, 1,2-benzoisothiazolin-3-one), acid amides, carbamic acid, carbamates, amidinesguanidines, pyridines (e.g., sodium pyridinethione-1-oxide), diazines, triazines, pyrroles.imidazoles, oxazoles.oxazines, thiazoles.thiadiazines, thioureas, thiosemicarbazides, dithiocarbamates, sulfides, sulfoxides, sulfones, sulfamides, antibiotics (e.g., penicillin, tetracyclin), sodium dehydroacetate, sodium benzoate, ethyl p-hydroxybenzoate, and salts thereof. Also, antiseptics described, for example, in Bokin Bobi Handbook (Handbook of Microbicide and Fungicide), Gihodo (1986), and Bokin Bobai Zai Jiten (Dictionary of Microbicide and Fungicide), compiled by Nippon Bokin Bobai Gakkai Jiten Henshu Iinkai, can be used.
Various compounds having an oil-soluble structure or a water-soluble structure may be used therefor, but a water-soluble compound is preferred.
Particularly, in the present invention, when two or more of these antiseptics are used in combination, the ejection stability after long-term aging of the ink is remarkably enhanced and the effect of the present invention is more successfully brought out. In using two or more antiseptics in combination, these are preferably differing in the skeleton of chemical structure. Furthermore, in the case of containing two or more antiseptics, at least one antiseptic is preferably a heterocyclic compound. For example, a combination of a heterocyclic compound and an antibiotic, or a combination of a heterocyclic compound and a phenol derivative is preferred. In using two antiseptics in combination, the content ratio therebetween is not limited but is preferably in the range of antiseptic A/antiseptic B=0.01 to 100 (by mass).
The antiseptic can be used in a wide range of amount but the amount added thereof is preferably from 0.001 to 10 mass %, more preferably from 0.1 to 5 mass %.
The inkjet recording ink of the present invention preferably contains. By containing the a surfactant, the liquid properties of the ink are controlled and this can provide excellent effects such as enhancement of ejection stability of ink, improvement of water resistance of image, and prevention of bleeding of printed ink.
The surfactant content in the ink is preferably from 0.001 to 15 mass %, more preferably from 0.005 to 10 mass %, still more preferably from 0.01 to 5 mass %.
The inkjet recording ink of the present invention can be prepared by dissolving and/or dispersing the azo dye and the surfactant in an aqueous medium. The term “aqueous medium” as used in the present invention means water or a mixture of water and a small amount of water-miscible organic solvent, where additives such as wetting agent and stabilizer are added, if desired.
In preparing the ink of the present invention, in the case of a water-soluble ink, the dye and the surfactant are preferably first dissolved in water and thereafter, various solvents and additives are added, dissolved and mixed to provide a uniform ink solution.
For dissolving the dye and the like, various methods such as stirring, ultrasonic irradiation and shaking can be used. Among these, stirring is preferred. In performing the stirring, various systems known in this field can be used, such as flow stirring and stirring utilizing the shearing force by means of a reversal agitator or a dissolver. Also, a stirring method utilizing the shearing force with the bottom surface of a container, such as magnetic stirrer, can be advantageously used.
In the case where the azo or phthalocyanine dye is an oil-soluble dye, the ink can be prepared by dissolving the oil-soluble dye in a high boiling point organic solvent and emulsion-dispersing it in an aqueous medium.
Examples of the high boiling point organic solvent 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 (1, 1-diethylpropyl) phthalate), esters of phosphoric acid or phosphone (e.g., diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, 2-ethylhexyldiphenyl phosphate, dioctylbutyl phosphate, tricyclohexyl phosphate, tri-2-ethylhexyl phosphate, tridodecyl phosphate, di-2-ethylhexylphenyl phosphate), benzoic acid esters (e.g., 2-ethylhexyl benzoate, 2,4-dichlorobenzoate, dodecyl benzoate, 2-ethylhexyl-p-hydroxybenzoate), amides (e.g., N,N-diethyldodecanamide, N,N-diethyllaurylamide), alcohols or phenols (e.g., isostearyl alcohol, 2,4-di-tert-amylphenol), aliphatic esters (e.g., dibutoxyethyl succinate, di-2-ethylhexyl succinate, 2-hexyldecyl tetradecanoate, tributyl citrate, diethyl azelate, isostearyl lactate, trioctyl citrate), aniline derivatives (e.g., N,N-dibutyl-2-butoxy-5-tertoctylaniline), chlorinated paraffins (e.g., paraffins having a chlorine content of 10 to 80%), trimesic acid esters (e.g., tributyl trimesate), dodecylbenzene, diisopropylnaphthalene, phenols (e.g., 2,4-di-tert-amylphenol, 4-dodecyloxyphenol, 4-dodecyloxycarbonylphenol, 4-(4-dodecyloxyphenylsulfonyl)phenol), carboxylic acids (e.g., 2-(2,4-di-tert-amylphenoxy)butyric acid, 2-ethoxyoctane-decanoic acid) and alkylphosphoric acids (e.g., di-(2-ethylhexyl)phosphoric acid and diphenylphosphoric acid). The high boiling point organic solvent can be used in an amount of, in terms of mass ratio to the oil-soluble dye, from 0.01 to 3 times, preferably from 0.01 to 1.0 times.
These high boiling point organic solvents may be used individually or as a mixture of several kinds [for example, tricresyl phosphate and dibutyl phthalate, trioctyl phosphate and di(2-ethylhexyl)sebacate, or dibutyl phthalate and poly(N-tert-butylacrylamide)].
Examples of the high boiling point organic solvent for use in the present invention, other than the above-described compounds, and/or the synthesis method of these high boiling point organic solvents are described in U.S. Pat. Nos. 2,322,027, 2,533,514, 2,772,163, 2,835,579, 3,594,171, 3,676,137, 3,689,271, 3,700,454, 3,748,141, 3,764,336, 3,765,897, 3,912,515, 3,936,303, 4,004,928, 4,080,209, 4,127,413, 4,193,802, 4,207,393, 4,220,711, 4,239,851, 4,278,757, 4,353,979, 4,363,873, 4,430,421, 4,430,422, 4,464,464, 4,483,918, 4,540,657, 4,684,606, 4,728,599, 4,745,049, 4,935,321 and 5,013,639, EP-A-276319, EP-A-286253, EP-A-289820, EP-A-309158, EP-A-309159, EP-A-309160, EP-A-509311, EP-A-510576, East German Patents 147,009, 157,147, 159,573 and 225,240A, British Patent 2091124A, JP-A-48-47335, JP-A-50-26530, JP-A-51-25133, JP-A-51-26036, JP-A-51-27921, JP-A-51-27922, JP-A-51-149028, JP-A-52-46816, JP-A-53-1520, JP-A-53-1521, JP-A-53-15127, JP-A-53-146622, JP-A-54-91325, JP-A-54-106228, JP-A-54-118246, JP-A-55-59464, JP-A-56-64333, JP-A-56-81836, JP-A-59-204041, JP-A-61-84641, JP-A-62-118345, JP-A-62-247364, JP-A-63-167357, JP-A-63-214744, JP-A-63-301941, JP-A-64-9452, JP-A-64-9454, JP-A-64-68745, JP-A-1-101543, JP-A-1-102454, JP-A-2-792, JP-A-2-4239, JP-A-2-43541, JP-A-4-29237, JP-A-4-30165, JP-A-4-232946 and JP-A-4-346338.
The high boiling point organic solvent can be used in an amount of, in terms of mass ratio to the oil-soluble dye, from 0.01 to 3 times, preferably from 0.01 to 1.0 times.
In the present invention, the oil-soluble dye or high boiling point organic solvent is used by emulsion-dispersing it in an aqueous medium. Depending on the case, a low boiling point organic solvent may be used in combination at the emulsion-dispersion in view of emulsifiability. The low boiling point organic solvent which can be used in combination is an organic solvent having a boiling point of about 30 to 150� C. under atmospheric pressure. Preferred examples thereof include, but are not limited to, esters (e.g., ethyl acetate, butyl acetate, ethyl propionate, β-ethoxyethyl acetate, methylcellosolve 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) and ethers (e.g., tetrahydrofuran, dioxane).
In the emulsion-dispersion, an oil phase obtained by dissolving the dye in a high boiling organic solvent or depending on the case, in a mixed solvent of a high boiling organic solvent and a low boiling organic solvent is dispersed in an aqueous phase mainly comprising water to form fine oil droplets of the oil phase. At this time, in either one or both of the aqueous phase and the oil phase, additives described later, such as surfactant, wetting agent, dye stabilizer, emulsification stabilizer and antiseptic, can be added, if desired.
In the general emulsification method, an oil phase is added to an aqueous phase, but a so-called phase inversion emulsification method of adding dropwise an aqueous phase in an oil phase can also be preferably used. This emulsification method can also be applied when the azo or phthalocyanine dye for use in the present invention is water-soluble and the additive is oil-soluble.
In performing the emulsion-dispersion, various surfactants can be used. Preferred examples thereof include anionic surfactants such as fatty acid salt, alkylsulfuric ester salt, alkylbenzenesulfonate, alkylnaphthalenesulfonate, dialkylsulfosuccinate, alkylphosphoric ester salt, naphthalenesulfonic acid formalin condensate and polyoxyethylene alkylsulfuric ester salt, and nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkylallyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester and oxyethylene oxypropylene block copolymer. Also, SURFYNOLS (produced by Air Products & Chemicals), which are an acetylene-base polyoxyethylene oxide surfactant, are preferably used. Furthermore, amine oxide-type amphoteric surfactants such as N,N-dimethyl-N-alkylamine oxide are preferred. In addition, surfactants described in JP-A-59-157636 (pages (37) to (38)) and Research Disclosure, No. 308119 (1989) can also be used.
For the purpose of stabilizing the dispersion immediately after emulsification, a water-soluble polymer may be added in combination with the surfactant. Preferred examples of the water-soluble polymer include polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, polyacrylic acid, polyacrylamide and copolymers thereof. Other than these, natural water-soluble polymers such as polysaccharides, casein and gelatin are also preferably used. Furthermore, for the stabilization of dye dispersion, a polymer which does not substantially dissolve in an aqueous medium, such as polyvinyl, polyurethane, polyester, polyamide, polyurea and polycarbonate obtained by the polymerization of acrylic acid esters, methacrylic acid esters, vinyl esters, acrylamides, methacrylamides, olefins, styrenes, vinyl ethers or acrylonitriles, can also be used in combination. This polymer preferably contains —SO3 − or —COO−. In the case of using this polymer which does not substantially dissolve in an aqueous medium, the polymer is preferably used in an amount of 20 mass % or less, more preferably 10 mass % or less, based on the high boiling point organic solvent.
In preparing an aqueous ink by dispersing the oil-soluble dye or high boiling point organic solvent according to emulsion-dispersion, the control of particle size is important. In order to elevate the color purity or density of an image formed by the inkjet recording, it is essential to reduce the average particle size. The average particle size is, in terms of the volume average particle size, preferably 1 μm or less, more preferably from 5 to 100 nm.
The volume average particle size and particle size distribution of the dispersed particles can be easily measured by a known method such as static light scattering method, dynamic light scattering method, centrifugal precipitation method and the method described in Jikken Kagaku Koza (Lecture of Experimental Chemistry), 4th ed., pp. 417-418. For example, the ink is diluted with distilled water to have a particle concentration of 0.1 to 1 mass %, then, the particle size can be easily measured by a commercially available volume average particle size measuring apparatus (for example, Microtrac UPA (manufactured by Nikkiso K.K.)). The dynamic light scattering method utilizing the laser Doppler effect is particularly preferred because even a small particle size can be measured.
The volume average particle size is an average particle size weighted with the particle volume and is obtained, by multiplying the diameter of individual particles in the gathering of particles by the volume of the particle and dividing the sum total of the obtained values by the total volume of the particles. The volume average particle size is described in Soichi Muroi, Kobunshi Latex no Kagaku (Chemistry of Polymer Latex), page 119, Kobunshi Kanko Kai.
A method of using two or more emulsifying apparatuses, for example, by performing the emulsification in a stirring emulsifier and then passing the emulsified product through a high-pressure homogenizer is particularly preferred. In addition, a method of once performing the emulsion-dispersion by such an emulsifying apparatus and after adding additives such as wetting agent and surfactant, again passing the dispersion through a high-pressure homogenizer during filling of the ink into a cartridge is also preferred.
The preparation method for the inkjet ink is described in detail in JP-A-5-148436, JP-A-5-295312, JP-A-7-97541, JP-A-7-82515 and JP-A-7-118584 and the methods described in these patent publications can be used also for the preparation of the inkjet recording ink of the present invention.
In the inkjet recording ink of the present invention, additives such as drying inhibitor for preventing clogging due to drying of ink at the ejection port, penetration accelerator for more successfully penetrating the ink into paper, ultraviolet absorbent, antioxidant, viscosity adjusting agent, surface tension adjusting agent, dispersant, dispersion stabilizer, rust inhibitor, pH adjusting agent, defoaming agent and chelating agent, may be appropriately selected and used in an appropriate amount.
The drying inhibitor for use in the present invention is preferably a water-soluble organic solvent having a vapor pressure lower than water. Specific examples thereof include polyhydric alcohols as represented by ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivative, glycerin and trimethylolpropane; lower alkyl ethers of polyhydric alcohol, such as ethylene glycol monomethyl(or ethyl) ether, diethylene glycol monomethyl(or ethyl) ether and triethylene glycol monoethyl(or butyl) ether; heterocyclic rings such as 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and N-ethylmorpholine; sulfur-containing compounds such as sulfolane, dimethylsulfoxide and 3-sulfolene; polyfunctional compounds such as diacetone alcohol and diethanolamine; and urea derivatives. Among these, polyhydric alcohols such as glycerin and diethylene glycol are preferred. These drying inhibitors may be used individually or in combination of two or more thereof. In the ink, the drying inhibitor is preferably contained in an amount of 10 to 50 mass %.
Examples of the penetration accelerator which can be used 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 surfactants. A sufficiently high effect can be obtained by adding from 10 to 30 mass % of the penetration accelerator in the ink. The penetration accelerator is preferably used in an amount of causing no blurring of printed letter or no print through.
As for the antioxidant which is used in the present invention for improving the preservability of images various organic or metal complex-base discoloration inhibitors can be used. Examples of the organic discoloration inhibitor include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines and heterocyclic rings. Examples of the metal complex include nickel complex and zinc complex. More specifically, compounds described in patents cited in Research Disclosure, Nos. 17643 (Items VII-I to VII-J), 15162, 18716 (page 650, left column), 36544 (page 527), 307105 (page 872) and 15162, and compounds included in formulae of representative compounds and in exemplary compounds described in JP-A-62-215272 (pages 127 to 137) can be used.
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and benzotriazole. In the ink, the rust inhibitor is preferably used in an amount of 0.02 to 5.00 mass %.
The ink of the present invention preferably has a viscosity of 30 mPa�s or less. The viscosity is more preferably adjusted to 20 mPa�s or less. For the purpose of adjusting the viscosity, a viscosity adjusting agent is sometimes used. Examples of the viscosity adjusting agent include water-soluble polymers such as celluloses and polyvinyl alcohol, and nonionic surfactants. The viscosity adjusting agent is described in detail in Nendo Chosei Gijutsu (Viscosity Adjusting Technology), Chap. 9, Gijutsu Joho Kyokai (1999), and Inkjet Printer Yo Chemicals (98 Zoho)-Zairyo no Kaihatsu Doko•Tenbo Chosa-(Chemicals for Inkjet Printer (Enlarged Edition of 98)-Survey on Development Tendency•Prospect of Materials-), pp. 162-174, CMC (1997).
In these uses, examples of the medium on which the pattern is formed include various materials such as paper, fiber, cloth (including non-woven fabric), plastic, metal and ceramic. Examples of the dyeing form include mordanting, printing and fixing of a coloring matter in the form of a reactive dye having introduced thereinto a reactive group. Among these, preferred is dyeing by mordanting.
The recording paper and recording film for use in the inkjet recording method of the present invention are described below. The support which can be used for the recording paper or film is produced, for example, from a chemical pulp such as LBKP and NBKP, a mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMP and CGP, or a waste paper pulp such as DIP, by mixing, if desired, conventionally known additives such as pigment, binder, sizing agent, fixing agent, cation agent and paper strength increasing agent, and then sheeting the mixture by using various devices such as Fourdrinier paper machine and cylinder paper machine. Other than these supports, synthetic paper or plastic film sheet may be used as the support. The thickness of the support is preferably from 10 to 250 μm and the basis weight is preferably from 10 to 250 g/m2.
An image-receiving layer and a backcoat layer may be provided on the support as it is to produce an image-receiving material for the ink of the present invention, or after providing a size press or an anchor coat layer by using starch, polyvinyl alcohol or the like, an image-receiving layer and a backcoat layer may be provided to produce an image-receiving material. The support may be further subjected to a flattening treatment by a calendering device such as machine calender, TG calender and soft calender.
Instead of the surfactant, an organofluoro compound may be used. The organofluoro compound is preferably hydrophobic. Examples of the organofluoro compound include fluorine-containing surfactants, oily fluorine-base compounds (for example, fluorine oil) and solid fluorine compound resins (for example, ethylene tetrafluoride resin) The organofluoro compound is described in JP-B-57-9053 (columns 8 to 17), JP-A-61-20994 and JP-A-62-135826.
The ink of the present invention is not limited in the inkjet recording system to which the ink is applied, and is used for a known system, for example, an electric charge control system of jetting out the ink by utilizing the electrostatic induction force, a drop-on-demand system (pressure pulse system) utilizing an oscillation pressure of a piezoelectric element, an acoustic inkjet system of converting electric signals into acoustic beams, irradiating the beams on the ink and jetting out the ink by utilizing the radiation pressure, and a thermal inkjet (bubble jet) system of heating the ink to form a bubble and utilizing the pressure generated.
The present invention is described below by referring to Examples, but the present invention is not limited thereto.
Also, Magenta Ink M-101 was prepared by increasing
Magenta Dye (a-36) to 23 g in the formulation above.
The oxidation potential of Magenta Dye (a-36) used here was nobler than 1.0 V (vs SCE).
Inks LM-102 to LM-109 and Inks M-102 to M-109 each having thoroughly the same composition as LM-101 or M-101 except for adding additives as shown in Table 1 below were produced.
2 g/liter of ethylene glycol to LM-
101, M-101
5 g/liter of ethylene glycol to LM-
2 g/liter of phenoxyethanol to LM-
5 g/liter of phenoxyethanol to LM-
2 g/liter of Proxel to LM-101, M-101
5 g/liter of Proxel to LM-101, M-101
1 g/liter of Proxel and 1 g/liter of
phenoxyethanol to LM-101, M-101
LM-109, M-109 (Invention)
2 g/liter of Proxel and 2 g/liter of
These inks each was filled in a magenta ink•light magenta ink cartridge of Inkjet Printer PM-950C (manufactured by Seiko Epson Corporation) and by using the inks of PM-950C for other colors, magenta monochromatic images differing in the density were printed. The image-receiving sheet where the image was printed was inkjet paper Photo Gloss Paper EX produced by Fuji Photo Film Co., Ltd. The image obtained was evaluated on the ejection property of ink and the image fastness.
This test was performed immediately after the filling of ink (ejection property A) and after the ink cartridge was stored for 2 weeks under the conditions of 40� C. and 80% RH (ejection property B).
(3) In the evaluation of ozone (O3) resistance, the photo gloss paper having formed thereon the image was left standing for 7 days in a box set to an ozone gas concentration of 0.5 ppm and the image density before and after standing in the ozone gas atmosphere was measured by a reflection densitometer (X-Rite 310TR) and evaluated in terms of the coloring matter residual ratio. The reflection density was measured at three points of 1, 1.5 and 2.0. The ozone gas concentration in the box was set by using an ozone gas monitor (Model OZG-EM-01) manufactured by APPLICS.
The sample was rated on a three-stage scale, namely, rated A when the coloring matter residual ratio was 80% or more at any density, rated B when less than 80% at one or two point(s), and rated C when less than 70% at all points.
Magenta ink�light
magenta ink for
PM-950 of
LM-107, M-107
LM-108, M-108
As seen from the results in the Table, the systems using the ink set of the present invention were satisfied in all performances and surpassed Comparative Examples. When the test for comparison of ejection property was performed after the ink cartridge was stored for 6 weeks under the conditions of 40� C. and 80% RH, the system using LM-108 and M-108 and the system using LM-109 and M-109 were stayed in the rank A, but other systems were decreased to the rank C. This reveals that when two or more antiseptics differing in the structure are contained in the present invention, the ejection stability after aging is more enhanced.
The color hue obtained by the ink of the present invention was equal to that of the ink for PM-950C of EPSON.
Also, when in Example 1, the magenta dye (a-36) was replaced by other dyes represented by formula (1) to produce the ink of the present invention, the same effects as in Example 1 were obtained in view of weather resistance (fastness to light, heat and ozone), ejection stability and color hue.
[Formulation of Light Cyan Ink (LC-101)]
Also, Cyan Ink Solution (C-101) was prepared by
increasing Cyan Dye (154) to 68 g in the formulation above.
[Formulation of Cyan Ink (C-101)]
The oxidation potential of Cyan Dye (154) used here was nobler than 1.0 V (vs SCE).
Inks (LC-102) to (LC-109) and Inks (C-102) to (C-109) each having thoroughly the same composition as Ink (LC-101) or (C-101) except for adding additives as shown in Table A below were produced.
2 g/liter of ethylene glycol to LC-
101, C-101
10 g/liter of ethylene glycol to LC-
2 g/liter of phenoxyethanol to LC-
5 g/liter of phenoxyethanol to LC-
2 g/liter of Proxel to LC-101, C-101
5 g/liter of Proxel to LC-101, C-101
phenoxyethanol to LC-101, C-101
LC-109, C-109 (Invention)
These inks each was filled in a cyan ink-light cyan ink cartridge of Inkjet Printer PM-950C (manufactured by Seiko Epson Corporation) and by using the inks of PM-950C for other colors, images differing in the density were printed. The image-receiving sheet where the image was printed was inkjet paper Photo Gloss Paper EX produced by Fuji Photo Film Co., Ltd. The image obtained was evaluated on the ejection property of ink and the image fastness in the same manner as in Example 1.
The results obtained are shown in Table B below.
O3 Property A
LC-107, C-107
LC-108, C-108
As seen from the results in Table B, the systems using the ink set of the present invention were satisfied in all performances and excellent as compared with Comparative Examples. When the test for comparison of ejection property was performed after the ink cartridge was stored for 6 weeks under the conditions of 40� C. and 80% RH, the system using Inks (LC-108) and (C-108) and the system using Inks (LC-109) and (C-109) were stayed in the rank A, but other systems were decreased to the rank C. This reveals that when two or more antiseptics differing in the structure are contained in the present invention, the ejection stability after aging is more enhanced.
According to the present invention, an inkjet recording ink which is an aqueous ink advantageous in view of handleability, odor, safety and the like and which ensures good color hue and excellent ejection stability even after long-term aging and exhibits excellent weather resistance can be provided.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3287470Jul 1, 1963Nov 22, 1966Geigy Ag J RMetal phthalocyanine dyestuffsUS5451251 *Feb 23, 1994Sep 19, 1995Canon Kabushiki KaishaInk, and ink-jet recording method and instrument using the sameUS5704969Apr 25, 1995Jan 6, 1998Seiko Epson CorporationAqueous ink composition and method of recording using the sameUS6582502Jan 24, 2001Jun 24, 2003Fuji Photo Film Co., Ltd.Dye, ink for ink jet recording, and ink jet recording methodUS20020107301 *Jul 17, 2001Aug 8, 2002Junichi YamanouchiColoring composition, ink for ink jet recording and ink jet recording methodUS20020158952 *Jan 17, 2002Oct 31, 2002Keiichi AdachiInk for ink jet recording and ink jet recording methodUS20030078320 *Sep 26, 2001Apr 24, 2003Masahiro YatakeInk set for ink jet-jet recording , method for ink-jet recording and recorded matterUS20030117474Aug 1, 2002Jun 26, 2003Toru HaradaInk composition for ink jet recording, ink jet recording method, composition for color toner, and composition for color filterUS20030213405Jan 15, 2003Nov 20, 2003Toru HaradaInk, ink jet recording method and azo compoundEP0020161A2May 30, 1980Dec 10, 1980EASTMAN KODAK COMPANY (a New Jersey corporation)Azodyestuffs derived from 5-membered heterocyclic amines and aromatic couplers containing sulpho-groups, or salts thereof and their use in dyeing polyamide fibresEP1364994A1Jan 18, 2002Nov 26, 2003Fuji Photo Film Co., Ltd.Phthalocyanine compound, ink, ink for ink-jet recording, ink-jet recording method and method for improving ozone gas resistance of colored imaging materialEP1388579A2Aug 6, 2003Feb 11, 2004Fuji Photo Film Co., Ltd.Ink, ink-jet-recording method and bis-azo compoundJP2000239584A Title not availableJP2002285050A Title not availableJP2003064275A Title not availableWO1996034916A2Apr 26, 1996Nov 7, 1996Bradbury RoyInk compositionWO2002060994A1Jan 18, 2002Aug 8, 2002Fuji Photo Film Co LtdPhthalocyanine compound, ink, ink for ink-jet recording, ink-jet recording method and method for improving ozone gas resistance of colored imaging materialWO2002083662A2Apr 8, 2002Oct 24, 2002Fuji Photo Film Co LtdAzo compounds and process of producing the same and novel intermediate compounds used in the process of producing azo compoundsWO2002083795A2 *Apr 8, 2002Oct 24, 2002Fuji Photo Film Co LtdColoring composition for image formation and method for improving ozone resistance of color imageWO2003000811A1Jun 21, 2002Jan 3, 2003Fuji Photo Film Co LtdColored image-forming compositions containing phthalocyanine compound, inks, inkjet inks, inkjet recording method and method of improving toleracne to decoloration due to ozone gasWO2003062324A1Jan 17, 2003Jul 31, 2003Fuji Photo Film Co LtdDye mixture and ink containing the sameWO2003087231A1Mar 17, 2003Oct 23, 2003Clariant GmbhMethod for producing vattable organic pigments* Cited by examinerNon-Patent CitationsReference1Kabushiki Kaisha Gijutsu Joho Kyokai, "Ink Jet Kiroku ni okeru Ink-Media-Printer no Kaiharsu Gijutsu," Kazuhiro Takausu, Feb. 1, 2001, p. 14.Classifications U.S. Classification347/100, 106/31.27, 347/95International ClassificationC09D11/00, C09D11/328, C09B47/26, C09B47/20, C09D11/38, G01D11/00Cooperative ClassificationC09D11/328, C09D11/32European ClassificationC09D11/32, C09D11/328Legal EventsDateCodeEventDescriptionAug 9, 2004ASAssignmentOwner name: FUJI PHOTO FILM CO., LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TAGUCHI, TOSHIKI;REEL/FRAME:016066/0548Effective date: 20040726Feb 15, 2007ASAssignmentOwner name: FUJIFILM CORPORATION,JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FUJIFILM HOLDINGS CORPORATION (FORMERLY FUJI PHOTO FILM CO., LTD.);REEL/FRAME:018904/0001Effective date: 20070130Sep 20, 2011FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services