JP2005225955A - Pigment dispersion system, container for pigment dispersion system, image formation product and image-forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pigment dispersion system which more reduces the average particle diameter of a pigment, a container for the pigment dispersion system which contains the pigment dispersion system, an image formation product formed by using the pigment dispersion system, and an image-forming method which forms an image by using the above pigment dispersion system. <P>SOLUTION: The pigment dispersion system comprises a pigment, a dispersing agent, and water, and the dispersing agent is a compound represented by the formula: A-O(CH<SB>2</SB>CH<SB>2</SB>O)<SB>n</SB>-H (wherein A is a substituted or nonsubstituted quinoline monovalent group or a substituted or nonsubstituted isoquinoline monovalent group; n is an integer of 10-100; A is preferably an 8-quinolinyl group; and n is preferably 40). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pigment dispersion system, a pigment dispersion system container, an image forming body, and an image forming method.

  Conventionally, as an inkjet ink used in an inkjet printer, a dye-based ink obtained by dissolving a water-soluble dye in water or a solvent composed of water and a water-soluble organic solvent, and adding additives as necessary, and a dispersant To disperse the pigment in water or a dispersion medium composed of water and a water-soluble organic solvent (hereinafter, a dispersion medium composed of water and water and a water-soluble organic solvent and containing water is referred to as an aqueous dispersion medium). Pigment-based inks obtained by

  Here, when a character or image is recorded on a recording medium using a pigment-based ink, compared to a case where a character or image is formed on a recording medium using a dye-based ink, the pigment-based ink is In general, it is superior in that it has higher water resistance and light resistance than dye-based inks. In other words, the solubility of pigments in water is generally much lower than the solubility of water-soluble inks in water, so even if water adheres to pigment-based inks dried on the recording material, the pigments adhere to the recording material. It hardly dissolves in the water, and bleeding of characters and images recorded on the recording medium hardly occurs. In addition, since the reactivity of the pigment to light is generally lower than the reactivity of the dye to light, the characters recorded on the recording medium even if the characters or images recorded on the recording medium are irradiated with light. There is little change in color tone or density of images.

  As the pigment-based ink, for example, an ink containing a polymer having both a hydrophilic structure portion and a hydrophobic structure portion such as a styrene-maleic acid copolymer and a sodium naphthalene sulfonate formalin condensate (see Patent Document 1). An ink using a polymer compound such as the above as a dispersant is known. In addition, an ink using a surfactant such as a polyethylene glycol phenyl ether derivative and a sulfate or phosphate of a polyethylene glycol phenyl ether derivative (see, for example, Patent Documents 2 and 3) as a dispersant is also known.

  In general, such a pigment-based ink is dispersed in a mixture containing a pigment, a dispersant, and an aqueous dispersion medium using a dispersing machine such as a ball mill and a sand mill to sufficiently disperse the pigment in the aqueous dispersion medium. It is produced by adding various additives to the pigment dispersion as required.

  In particular, with regard to pigment-based inks used for ink-jet inks, secondary characters of characters and images are used to record clear characters and images on a recording medium in order to prevent clogging of nozzles that discharge the pigment-based ink. In order to maintain reproducibility and ensure the transparency of the image in the pigment-based ink, the particle diameter of the pigment particles dispersed in the pigment dispersion system (particles having a dispersant attached to the pigment) is usually 200 nm or less, It is necessary to make the particles finer to 150 nm or less. Furthermore, in order to manufacture pigment-based inks industrially at low cost, it is necessary to make the pigment particles fine in a short time. Furthermore, in order to prevent clogging of the nozzle that discharges the pigment-based ink, in the pigment-based ink, the particle diameter of the finely divided pigment particles is changed with time and / or in a high or low temperature environment. It is also required not to increase.

  However, in the conventional pigment-based inks disclosed in Patent Documents 1, 2, and 3, the average particle diameter of the pigment particles is large, and the average particle diameter of the pigment particles increases with time. There is a problem. For this reason, when these pigment-based inks are used as inkjet inks, the frequency of clogging of nozzles that discharge the pigment-based inks increases. In addition, for these pigment-based inks, it has been difficult to make the pigment particles fine in a short time.

  On the other hand, a polyethylene glycol phenyl ether derivative having both a sulfone group and a carboxyl group is disclosed as a pigment-based ink in which the average particle size of pigment particles is reduced (see Patent Document 4). Furthermore, a polyethylene glycol naphthalenyl ether derivative has been disclosed as a pigment-based ink that can efficiently make fine particles of pigment particles in a short time, and that the increase in the average particle size of the pigment particles with time is reduced. (For example, refer to Patent Document 5).

However, even the conventional pigment-based inks disclosed in Patent Documents 4 and 5 have a problem that the average particle diameter of the pigment particles is not sufficiently small.
JP-A-56-147863 Japanese Patent Laid-Open No. 10-88050 JP-A-10-168367 JP 2002-38072 A JP 2001-192583 A

  The present invention relates to a pigment dispersion system in which the average particle size of the pigment particles is further reduced, a pigment dispersion container containing the pigment dispersion system, an image forming body formed using the pigment dispersion system, and the It is an object of the present invention to provide an image forming method for forming an image using a pigment dispersion system.

The invention according to claim 1 is a pigment dispersion system comprising a pigment, a dispersant, and water, wherein the dispersant is represented by the general formula (1).
_{A-O (CH 2 CH 2} O) n -H
Wherein A is a monovalent group of substituted or unsubstituted quinoline or a monovalent group of substituted or unsubstituted isoquinoline, and n is an integer of 10 or more and 100 or less. To do.

According to invention of Claim 1, the said dispersing agent is general formula (1).
_{A-O (CH 2 CH 2} O) n -H
A is a monovalent group of a substituted or unsubstituted quinoline or a monovalent group of a substituted or unsubstituted isoquinoline, and n is an integer of 10 or more and 100 or less. A pigment dispersion system in which the average particle size of the particles is further reduced can be provided.

  According to a second aspect of the present invention, in the pigment dispersion system according to the first aspect, A is an 8-quinolinyl group.

  According to the invention described in claim 2, since A is an 8-quinolinyl group, a pigment dispersion system in which the average particle size of the pigment particles is further reduced can be provided at a low cost.

  The invention described in claim 3 is characterized in that, in the pigment dispersion system according to claim 1 or 2, n is 40.

  According to the invention of claim 3, since n is 40, it is possible to provide a pigment dispersion system in which the average particle diameter of the pigment particles is more effectively reduced.

The invention according to claim 4 is the pigment dispersion system according to any one of claims 1 to 3, wherein the general formula (2)
_{^{R 1 - (A 1) m}} -OH
R ¹ is an alkyl group having 8 to 14 carbon atoms, A ¹ is a divalent group containing at least ^one of an oxyethylene unit and an oxypropylene unit, and m is It is an integer of 3 or more and 16 or less.

According to invention of Claim 4, General formula (2)
_{^{R 1 - (A 1) m}} -OH
R ¹ is an alkyl group having 8 to 14 carbon atoms, A ¹ is a divalent group containing at least ^one of an oxyethylene unit and an oxypropylene unit, and m is Since it is an integer of 3 or more and 16 or less, fluctuations in the average particle diameter of the pigment particles in the pigment dispersion can be suppressed.

  The invention according to claim 5 is the pigment dispersion according to claim 4, wherein the content of the compound represented by the general formula (2) with respect to the compound represented by the general formula (1) is 0.001% by weight or more. It is characterized by being 40% by weight or less.

  According to invention of Claim 5, since content of the compound represented by General formula (2) with respect to the compound represented by General formula (1) is 0.001 to 40 weight%, It can suppress more effectively that the average particle diameter of the pigment particle in a pigment dispersion system fluctuates.

A sixth aspect of the present invention is the pigment dispersion system according to any one of the first to fifth aspects, wherein the general formula (3)
H
｜
_{^{M 1 O 3 S-C-}} COOR 2
｜
H ₂ C-COOR ³
And R ² and R ³ are each an alkyl group having 1 to 20 carbon atoms, and M ¹ is H, Li, Na, K, or N ⁺ R ⁴ R ⁵ R ⁶ R ⁷ , wherein R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, and a 3-hydroxypropyl group. It is characterized by that.

According to invention of Claim 6, General formula (3)
H
｜
_{^{M 1 O 3 S-C-}} COOR 2
｜
H ₂ C-COOR ³
And R ² and R ³ are each an alkyl group having 1 to 20 carbon atoms, and M ¹ is H, Li, Na, K, or N ⁺ R ⁴ R ⁵ R ⁶ R ⁷ , wherein R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, and a 3-hydroxypropyl group. Therefore, fluctuations in the average particle size of the pigment particles in the pigment dispersion system can be suppressed.

  The invention according to claim 7 is the pigment dispersion according to claim 6, wherein the content of the compound represented by the general formula (3) with respect to the compound represented by the general formula (1) is 0.001% by weight or more. It is characterized by being 40% by weight or less.

  According to invention of Claim 7, since content of the compound represented by General formula (3) with respect to the compound represented by General formula (1) is 0.001 to 40 weight%, It can suppress more effectively that the average particle diameter of the pigment particle in a pigment dispersion system fluctuates.

The invention according to claim 8 is the pigment dispersion system according to any one of claims 1 to 7, wherein the general formula (4)
^{_{R 8 O- (A 2) n}} -CH 2 COOM 2
R ⁸ is an alkyl group having 1 to 20 carbon atoms, A ² is a divalent group containing at least one of an oxyethylene unit and an oxypropylene unit, and n is Is an integer of 1 to 12, M ² is H, Li, Na, K, or N ⁺ R ⁹ R ¹⁰ R ¹¹ R ¹² , and R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are each , A hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, and a 3-hydroxypropyl group.

According to invention of Claim 8, General formula (4)
^{_{R 8 O- (A 2) n}} -CH 2 COOM 2
R ⁸ is an alkyl group having 1 to 20 carbon atoms, A ² is a divalent group containing at least one of an oxyethylene unit and an oxypropylene unit, and n is Is an integer of 1 to 12, M ² is H, Li, Na, K, or N ⁺ R ⁹ R ¹⁰ R ¹¹ R ¹² , and R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are each , A hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, and a 3-hydroxypropyl group, so that fluctuations in the average particle diameter of the pigment particles in the pigment dispersion are suppressed. Can do.

  The invention according to claim 9 is the pigment dispersion according to claim 8, wherein the content of the compound represented by the general formula (4) with respect to the compound represented by the general formula (1) is 0.001% by weight or more. It is characterized by being 40% by weight or less.

  According to invention of Claim 9, since content of the compound represented by General formula (4) with respect to the compound represented by General formula (1) is 0.001 to 40 weight%, It can suppress more effectively that the average particle diameter of the pigment particle in a pigment dispersion system fluctuates.

  A tenth aspect of the present invention is the pigment dispersion system according to any one of the first to ninth aspects, wherein the pigment is Pigment Yellow 74.

  According to the tenth aspect of the present invention, since the pigment is pigment yellow 74, it is possible to improve the reproducibility of the color tone of yellow (yellow) of the pigment dispersion in the pigment dispersion receiver.

  The invention according to claim 11 is the pigment dispersion system according to any one of claims 1 to 9, wherein the pigment is pigment red 122 and / or pigment violet 19.

  According to the eleventh aspect of the invention, since the pigment is Pigment Red 122 and / or Pigment Violet 19, the reproducibility of the magenta color tone of the pigment dispersion in the pigment dispersion receiver is improved. Can be made.

  The invention according to claim 12 is the pigment dispersion system according to any one of claims 1 to 9, wherein the pigment is β-type phthalocyanine copper.

  According to the twelfth aspect of the present invention, since the pigment is β-type phthalocyanine copper, the reproducibility of the green-blue (cyan) color tone of the pigment dispersion in the pigment dispersion receiver can be improved.

  The invention according to claim 13 is the pigment dispersion system according to any one of claims 1 to 9, wherein the pigment is carbon black.

  According to the thirteenth aspect of the invention, since the pigment is carbon black, it is possible to improve the reproducibility of the black color tone of the pigment dispersion in the pigment dispersion receiver.

  The invention according to claim 14 is the pigment dispersion system according to any one of claims 1 to 13, wherein at least one selected from the group consisting of water-soluble organic solvents, surfactants, preservatives, and fungicides. It further includes an additive.

  According to the invention described in claim 14, since it further includes at least one additive selected from the group consisting of a water-soluble organic solvent, a surfactant, a preservative, and a fungicide, the property resulting from the additive Provided pigment dispersions can be provided.

  The invention according to claim 15 is the pigment dispersion system according to any one of claims 1 to 14, wherein the content of the dispersant with respect to the pigment is 6.25% by weight or more and 50% by weight or less. And

  According to the invention of claim 15, since the content of the dispersant with respect to the pigment is 6.25% by weight or more and 50% by weight or less, the average particle diameter of the pigment particles in the pigment dispersion system varies. Can be improved, and the viscosity of the pigment dispersion can be prevented from becoming too high.

  A sixteenth aspect of the present invention is the pigment dispersion system according to any one of the first to fifteenth aspects, wherein the average particle diameter of the pigment particles is 10 nm or more and 200 nm or less.

  According to the invention described in claim 16, since the average particle diameter of the pigment particles is 10 nm or more and 200 nm or less, it is possible to suppress a decrease in light resistance of the pigment dispersion system in the receptor, and to the receptor. It is also possible to suppress a decrease in the vividness of the color tone of the pigment dispersion.

  The invention according to claim 17 is the pigment dispersion system according to any one of claims 1 to 16, wherein the concentration of the pigment is 1% by weight or more and 50% by weight or less.

  According to the invention of claim 17, since the concentration of the pigment is 1% by weight or more and 50% by weight or less, the pigment dispersion can be prepared in a short time and the viscosity of the pigment dispersion becomes too high. This can be suppressed.

  The invention according to claim 18 is characterized in that the pigment dispersion system according to any one of claims 1 to 17 is housed in a pigment dispersion system container.

  According to the invention described in claim 18, since the pigment dispersion system according to any one of claims 1 to 17 is accommodated, the pigment dispersion system in which the average particle diameter of the pigment particles is further reduced is accommodated. A pigment dispersion container can be provided.

  According to a nineteenth aspect of the present invention, in the pigment dispersion containing body according to the eighteenth aspect, the image forming apparatus is detachable.

  According to the nineteenth aspect of the present invention, since it is detachable from the image forming apparatus, a pigment dispersion system in which the average particle diameter of the pigment particles is further reduced can be easily installed and replaced in the image forming apparatus.

  According to a twentieth aspect of the present invention, in the image forming body, an image is formed on the receiver using the pigment dispersion system according to any one of the first to seventeenth aspects.

  According to the invention described in claim 20, since the image is formed on the receiver using the pigment dispersion system according to any one of claims 1 to 17, the average particle diameter of the pigment particles is further reduced. An image forming body formed by using a pigment dispersion system can be provided.

  According to a twenty-first aspect of the present invention, in the image forming method, an image is formed on a receptor using the pigment dispersion system according to any one of the first to seventeenth aspects.

  According to the invention of claim 21, since the image is formed on the receiver using the pigment dispersion system of any one of claims 1 to 17, the pigment dispersion in which the average particle diameter of the pigment particles is further reduced An image forming method for forming an image using a system can be provided.

  According to a twenty-second aspect of the present invention, in the image forming method according to the twenty-first aspect, the pigment dispersion system is discharged from the image forming apparatus to the receiver.

  According to the twenty-second aspect of the present invention, since the pigment dispersion system is discharged from the image forming apparatus to the receiver, desired images can be formed on various types of receivers.

  According to a twenty-third aspect of the present invention, in the image forming method according to the twenty-second aspect, the image forming apparatus is an ink jet printer.

  According to the twenty-third aspect of the present invention, since the image forming apparatus is an ink jet printer, a desired image can be formed on the receptor using a simple mechanism. be able to.

  According to a twenty-fourth aspect of the present invention, in the image forming method according to the twenty-third aspect, the ink jet printer is a piezo type ink jet printer.

  According to the invention of claim 24, since the ink jet printer is a piezo ink jet printer, the amount of the pigment dispersion discharged from the image forming apparatus can be controlled in a complicated manner.

  According to a twenty-fifth aspect of the present invention, in the image forming method according to the twenty-third aspect, the ink jet printer is a thermal type ink jet printer.

  According to the invention described in claim 25, since the ink jet printer is a thermal ink jet printer, the pigment dispersion system can be discharged from the image forming apparatus at a high speed.

  According to the present invention, a pigment dispersion system in which the average particle size of the pigment particles is further reduced, a pigment dispersion system container in which the pigment dispersion system is contained, an image forming body formed using the pigment dispersion system, And an image forming method for forming an image using the pigment dispersion system.

  Next, embodiments of the present invention will be described in more detail.

First, the pigment dispersion system according to the present invention will be described. The pigment dispersion system according to the present invention includes at least a pigment, a dispersant, and water. The dispersant for dispersing pigment particles in a dispersion medium containing water is represented by the general formula (1).
_{A-O (CH 2 CH 2} O) n -H
It is a compound represented by these.

  In the general formula (1), A is a monovalent group of a substituted or unsubstituted quinoline or a monovalent group of a substituted or unsubstituted isoquinoline. Quinoline has the formula

で表される化合物であり、イソキノリンは、式

And isoquinoline is represented by the formula:

で表される化合物である。

It is a compound represented by these.

  In A, the position of the free valence in the monovalent group of the substituted or unsubstituted quinoline, or the position of the free valence in the monovalent group of the substituted or unsubstituted isoquinoline is substituted or unsubstituted quinoline, or substituted or unsubstituted. Any position of the carbon atoms constituting the quinoline ring or isoquinoline ring in a substituted isoquinoline is possible.

  In A, when the monovalent group of substituted or unsubstituted quinoline is a monovalent group of substituted quinoline, or when the monovalent group of substituted or unsubstituted isoquinoline is a monovalent group of substituted isoquinoline Is a substituent in a monovalent group of a substituted quinoline, or a substituent in a monovalent group of a substituted isoquinoline is a linear or branched alkyl group containing 1 to 20 carbon atoms, 1 to 20 Or at least one substituent selected from an aryl group containing 1 to 20 carbon atoms.

  Examples of the linear or branched alkyl group containing 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and a straight chain. Or branched pentyl group, linear or branched hexyl group, linear or branched heptyl group, linear or branched octyl group, linear or branched nonyl group, linear or branched decyl group, linear or branched Undecyl group, linear or branched dodecyl group, linear or branched tridecyl group, linear or branched tetradecyl group, linear or branched pentadecyl group, linear or branched hexadecyl group, linear or branched heptadecyl Group, a linear or branched octadecyl group, a linear or branched nonadecyl group, and a linear or branched icosyl group.

  Examples of the aryl group containing 1 to 20 carbon atoms include a phenyl group, 1- or 2-naphthalenyl group, 1-, 2-, or 9-anthracenyl group, 1-, 2-, 3-, 4 -, Or 9-phenanthrenyl group, 1-, 2-, or 5-naphthacenyl group, 1-, 2-, or 3-pyrenyl group, and 1-, 2-, 3-, 4-, 5-, or 6 -A chrysenyl group etc. are mentioned.

  Examples of the aralkyl group containing 1 to 20 carbon atoms include benzyl group, phenethyl group, γ-phenylpropyl group, 1- or 2-naphthalenylmethyl group, β- (1- or 2-naphthalenyl). Examples thereof include an ethyl group and a γ- (1- or 2-naphthalenyl) propyl group.

  In the monovalent group of substituted quinoline or the monovalent group of substituted isoquinoline, 1 to 6 hydrogen atoms in the monovalent group of quinoline or the monovalent group of isoquinoline are substituted with the above-described substituent. That is, the number of substituents in the monovalent group of substituted quinoline or the monovalent group of substituted isoquinoline is 1 or more and 6 or less. Regarding the position of the substituent in the monovalent group of substituted quinoline or the monovalent group of substituted isoquinoline, the hydrogen atom at any position in the monovalent group of substituted quinoline or monovalent group of substituted isoquinoline is substituted. When the number of substituents in the monovalent group of substituted quinoline or the monovalent group of substituted isoquinoline is plural, these plural substituents may be the same substituent or different substituents. Also good.

  Here, A is preferably an 8-quinolinyl group.

である。Ａが、８−キノリニル基であるときには、本発明による顔料分散系に使用される分散剤は、式

It is. When A is an 8-quinolinyl group, the dispersant used in the pigment dispersion according to the invention has the formula

で表される。このようにＡが、８−キノリニル基であると、上記分散剤の原料である８−ヒドロキシキノリンを容易に入手することができるため、顔料分散系を安価に調製することができる。

It is represented by Thus, when A is an 8-quinolinyl group, 8-hydroxyquinoline, which is a raw material for the dispersant, can be easily obtained, so that a pigment dispersion can be prepared at low cost.

  In the general formula (1), n is an integer of 10 or more and 100 or less, preferably an integer of 20 or more and 60 or less, and most preferably 40. When n is less than 10, the dispersibility of the pigment particles decreases in the pigment dispersion system, the pigment particles aggregate, and the average particle size of the pigment particles increases. On the other hand, when n exceeds 100, the viscosity of the pigment dispersion increases. As a result, when the pigment dispersion system is used as an ink jet ink, clogging of the nozzle that discharges the pigment dispersion system is easily caused. In the pigment dispersion system, the average particle diameter of the pigment particles tends to fluctuate easily (the stability of the average particle diameter of the pigment particles decreases).

  When A is an 8-quinolinyl group and n is 40, the dispersant used in the pigment dispersion according to the present invention is particularly preferable,

で表される化合物である。すなわち、Ａが８−キノリニル基であり、ｎが４０であると、顔料分散系における顔料の粒子の平均粒径をさらに効果的に低減させることができる。

It is a compound represented by these. That is, when A is an 8-quinolinyl group and n is 40, the average particle diameter of the pigment particles in the pigment dispersion can be further effectively reduced.

  As the dispersant in the pigment dispersion system according to the present invention, one kind of compound represented by the above general formula (1) may be used alone, or a plurality of kinds of compounds represented by the above general formula (1). May be used in combination.

  The pigment used in the pigment dispersion according to the present invention is not particularly limited. For example, the following inorganic pigments and organic pigments can be used according to the color required for the pigment dispersion.

  Examples of black pigments (black pigments) include carbon blacks such as furnace black, lamp black, acetylene black, and channel black, metals such as copper, iron, and titanium oxide, and ortho-nitroaniline. Examples thereof include organic pigments such as black.

  As pigments for yellow (yellow pigments), Pigment Yellow 1, Pigment Yellow 2, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 16, Pigment Yellow 17, Pigment Yellow 73, Pigment Yellow 74 Pigment Yellow 75, Pigment Yellow 83, Pigment Yellow 93, Pigment Yellow 95, Pigment Yellow 97, Pigment Yellow 98, Pigment Yellow 114, Pigment Yellow 120, Pigment Yellow 128, Pigment Yellow 129, Pigment Yellow 138, Pigment Yellow 150, Pigment Yellow 151, pigment yellow 154, pigment yellow 155, and pigment i Low 180, and the like.

  As pigments for magenta (magenta pigments), Pigment Red 5, Pigment Red 7, Pigment Red 12, Pigment Red 48 (Ca), Pigment Red 48 (Mg), Pigment Red 57 (Ca), Pigment Red 57: 1 Pigment Red 112, Pigment Red 122, Pigment Red 123, Pigment Red 168, Pigment Red 184, Pigment Red 202, Pigment Violet 19, and the like.

  Pigment blue 1, pigment blue 2, pigment blue 3, pigment blue 15, pigment blue 15: 3, pigment blue 15: 4, pigment blue 16, pigment blue 22, pigment blue are pigments for green-blue (cyan pigment). 60, Bat Blue 4, Bat Blue 60, and the like.

  Color pigments other than the above include toluidine red, permanent carmine FB, first yellow AAA, disazo orange PMP, lake red C, brilliant carmine 6B, phthalocyanine blue, quinacridone red, dioxane violet, Victoria pure blue, alkali blue toner, first yellow. 10G, Disazo Yellow AAMX, Disazo Yellow AAOT, Disazo Yellow AAOA, Yellow Iron Oxide, Disazo Yellow HR, Orthonitroaniline Orange, Dinitroaniline Orange, Vulcan Orange, Toluidine Red, Chlorinated Parared, Brilliant First Scarlet, Naphthol Red 23, Pyrazolone Red, Barium Red 2B, Calcium Red 2B, Strontium Red 2B, Manga Red 2B, Barium Resome Red, Pigment Scar Red 3B Lake, Lake Bordeaux 10B, Ansosin 3B Lake, Ansosin 5B Lake, Rhodamine 6G Lake, Eosin Lake, Bengala, Fanatall Red FGR, Rhodamine B Lake, Methyl Bio Red Lake, Di Oxazine Bio Red, Basic Blue 5B Lake, Basic Blue 6G Lake, Fast Sky Blue, Alkali Blue R Toner, Peacock Blue Lake, Bitumen, Ultra Blue, Reflex Blue 2G, Reflex Blue R, Brilliant Green Lake, Diamond Green Thioflavin Lake , Phthalocyanine green G, green gold, phthalocyanine green Y, iron oxide powder, rust, zinc white, titanium oxide, calcium carbonate, clay Barium sulfate, alumina, alumina white, aluminum powder, bronze powder, daylight fluorescent pigment, pearl pigment, naphthol carmine FB, naphthol red M, permanent carmine FB, first yellow G, disazo yellow AAA, dioxane bio red, alkali blue G toner, etc. Is mentioned.

  In addition, a processed pigment such as graft carbon obtained by treating the surface of the pigment with a resin or the like can also be used. Furthermore, a plurality of types of the above pigments can be mixed and used according to the color required for the pigment dispersion system.

  In the above pigments, the dispersibility of pigment particles in the pigment dispersion system, the reproducibility of the color tone of the pigment dispersion system in the pigment dispersion receiver such as paper and film, and the light resistance of the pigment dispersion system in the receiver are improved. For this purpose, carbon black is used as a black pigment, pigment yellow 74 is used as a yellow pigment, pigment red 122 and / or pigment violet 19 is used as a magenta pigment, and pigment blue 15 is used as a cyan pigment. It is preferable to use β-type phthalocyanine copper such as: 3 and Pigment Blue 15: 4. Further, when the surfaces of Pigment Red 122 and Pigment Violet 19 are treated with a pigment derivative or the like as a magenta pigment, the dispersibility of pigment particles in the pigment dispersion system can be improved.

  Here, the average particle diameter of the pigment particles in the pigment dispersion system is preferably 10 nm or more and 200 nm or less. When the average particle diameter of the pigment particles in the pigment dispersion is less than 10 nm, the pigment particles in the pigment dispersion are not easily dispersed, and the cost for preparing the pigment dispersion increases. In addition, the storage stability of the pigment dispersion and the light resistance of the pigment dispersion in the pigment dispersion receiver such as paper and film tend to be lowered. When the average particle diameter of the pigment particles in the pigment dispersion system exceeds 200 nm, when the pigment dispersion system is used as an inkjet ink, it is likely to cause clogging of the nozzle that ejects the ink. In addition, the sharpness of the color tone of an image formed on an ink receiver such as paper and film tends to decrease.

  In the present invention, the average particle diameter of the pigment particles is specifically defined by the dispersion agent adhering to the primary particles of the pigment dispersed in the pigment dispersion system and the secondary particles in which the primary particles are aggregated. Means the average particle size of the produced particles. In the pigment dispersion system of the present invention, the average particle diameter of the pigment particles is a value measured by Nikkiso Co., Ltd. Microtrac UPA.

  The concentration of the pigment in the pigment dispersion system is preferably 1% by weight or more and 50% by weight or less. More specifically, when the pigment dispersion according to the present invention is used as an ink stock solution (pigment dispersion), the concentration of the pigment in the pigment dispersion is preferably 5% by weight or more and 50% by weight or less. At this time, if the concentration of the pigment in the pigment dispersion is less than 5% by weight, the concentration of the pigment in the pigment dispersion as the ink stock solution is too low to prepare a pigment dispersion containing a certain amount of pigment. In order to do so, a large amount of pigment dispersion is required. As a result, it takes a long time to prepare a large amount of the pigment dispersion system, and the productivity of the pigment dispersion system as an ink stock solution is lowered. When the concentration of the pigment in the pigment dispersion exceeds 50%, the viscosity of the pigment dispersion becomes too high, and it tends to be difficult to disperse the pigment particles in the pigment dispersion. When the pigment dispersion system according to the present invention is used as an ink jet ink, the pigment concentration in the pigment dispersion system is preferably 1% by weight or more and 30% by weight or less. When the concentration of the pigment in the pigment dispersion is less than 1% by weight, the density of the image formed on the pigment dispersion receiver such as paper and film is too low and formed on the receiver such as a print. The sharpness of the image tends to decrease. When the concentration of the pigment in the pigment dispersion exceeds 30% by weight, the viscosity of the pigment dispersion as an ink jet ink increases, and the nozzles that eject the ink are likely to be clogged.

  Furthermore, the content of the dispersant represented by the general formula (1) with respect to the pigment is preferably 6.25% by weight or more and 50% by weight or less. That is, the weight ratio of the pigment content in the pigment dispersion system to the dispersant content represented by the general formula (1) in the pigment dispersion system is preferably in the range of 1/15 to 1/1. is there. When the content of the dispersant represented by the general formula (1) with respect to the pigment is less than 6.25% by weight, it is difficult to sufficiently disperse the pigment particles in a dispersion medium such as water. The effect of suppressing fluctuations in the average particle diameter of the pigment particles in the pigment dispersion system is reduced. When the content of the dispersant represented by the general formula (1) with respect to the pigment exceeds 50% by weight, the viscosity of the pigment dispersion system becomes too high. As a result, when the pigment dispersion system according to the present invention is used as an inkjet ink, the viscosity of the ink is too high, so that it is difficult to eject the ink from the inkjet printer, and an image such as a print on an ink receiver is obtained. It tends to be difficult to form.

  The water contained in the pigment dispersion according to the present invention is preferably ion exchange water.

The pigment dispersion according to the present invention preferably has a general formula (2) in addition to the pigment, the dispersant represented by the general formula (1), and water.
_{^{R 1 - (A 1) m}} -OH
The compound (surfactant) represented by these is further included. Here, R ¹ is preferably an alkyl group having 8 to 14 carbon atoms. When R ¹ is an alkyl group having 7 or less carbon atoms or 15 or more carbon atoms, the average particle size of the pigment particles in the pigment dispersion system tends to vary easily. A ¹ is preferably a divalent group containing at least one of an oxyethylene unit and an oxypropylene unit. Therefore, as A ^1, oxyethylene units, oxypropylene units, and any combination of oxyethylene and oxypropylene units can be suitably used. m is preferably an integer of 3 to 16. When m is 2 or less or 17 or more, the effect of suppressing fluctuations in the average particle diameter of the pigment particles in the pigment dispersion system is reduced.

  Here, the content of the compound represented by the general formula (2) with respect to the compound represented by the general formula (1) is preferably 0.001 wt% or more and 40 wt% or less. That is, the weight ratio between the content of the compound represented by the general formula (1) and the content of the compound represented by the general formula (2) is preferably 99.999 / 0.001 to 60/40. Is in range. When the content of the compound represented by the general formula (2) with respect to the compound represented by the general formula (1) is less than 0.001% by weight, the compound represented by the general formula (2) is added. Since there is almost no effect of improving the dispersibility of the pigment particles in the pigment dispersion system, the degree to which the average particle diameter of the pigment particles in the pigment dispersion system is prevented from fluctuating is small. In addition, even when the content of the compound represented by the general formula (2) with respect to the compound represented by the general formula (1) exceeds 40% by weight, the average particle diameter of the pigment particles in the pigment dispersion varies. The degree to which it is suppressed becomes small.

The pigment dispersion according to the present invention is preferably a general formula (3) in addition to the pigment, the dispersant represented by the general formula (1), and water.
H
｜
_{^{M 1 O 3 S-C-}} COOR 2
｜
H ₂ C-COOR ³
The compound (surfactant) represented by these is further included. Here, R ² and R ³ are each preferably an alkyl group having 1 to 20 carbon atoms. When R ² and / or R ³ is a hydrogen atom or an alkyl group having 21 or more carbon atoms, the average particle diameter of the pigment particles in the pigment dispersion tends to vary easily. M ¹ is preferably H, Li, Na, K, or N ⁺ R ⁴ R ⁵ R ⁶ R ⁷ . Further, R ⁴ , R ⁵ , R ⁶ and R ⁷ are each preferably selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, and a 3-hydroxypropyl group.

  Here, the content of the compound represented by the general formula (3) with respect to the compound represented by the general formula (1) is preferably 0.001 wt% or more and 40 wt% or less. That is, the weight ratio between the content of the compound represented by the general formula (1) and the content of the compound represented by the general formula (3) is preferably 99.999 / 0.001 to 60/40. Is in range. When the content of the compound represented by the general formula (3) with respect to the compound represented by the general formula (1) is less than 0.001% by weight, the compound represented by the general formula (3) is added. Since there is almost no effect of improving the dispersibility of the pigment particles in the pigment dispersion system, the degree to which the average particle diameter of the pigment particles in the pigment dispersion system is prevented from fluctuating is small. Further, even when the content of the compound represented by the general formula (3) with respect to the compound represented by the general formula (1) exceeds 40% by weight, the average particle size of the pigment particles in the pigment dispersion system varies. The degree to which it is suppressed becomes small.

The pigment dispersion according to the present invention is preferably a general formula (4) in addition to the pigment, the dispersant represented by the general formula (1), and water.
^{_{R 8 O- (A 2) n}} -CH 2 COOM 2
The compound (surfactant) represented by these is further included. Here, R ⁸ is preferably an alkyl group having 1 to 20 carbon atoms. When R ⁸ is a hydrogen atom or an alkyl group having 21 or more carbon atoms, the effect of suppressing fluctuations in the average particle size of the pigment particles in the pigment dispersion system is reduced. A ² is preferably a divalent group containing at least one of an oxyethylene unit and an oxypropylene unit. Therefore, as A ^2, oxyethylene units, oxypropylene units, and any combination of oxyethylene and oxypropylene units can be suitably used. Further, n is preferably an integer of 1 or more and 12 or less. When n is 0 or 13 or more, the average particle diameter of the pigment particles in the pigment dispersion system tends to vary easily. In addition, M ² is preferably H, Li, Na, K, or N ⁺ R ⁹ R ¹⁰ R ¹¹ R ¹² , wherein R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are each preferably , A hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, and a 3-hydroxypropyl group.

  Here, the content of the compound represented by the general formula (4) with respect to the compound represented by the general formula (1) is preferably 0.001 wt% or more and 40 wt% or less. That is, the weight ratio between the content of the compound represented by the general formula (1) and the content of the compound represented by the general formula (4) is preferably 99.999 / 0.001 to 60/40. Is in range. When the content of the compound represented by the general formula (4) with respect to the compound represented by the general formula (1) is less than 0.001% by weight, the compound represented by the general formula (4) is added. Since there is almost no effect of improving the dispersibility of the pigment particles in the pigment dispersion system, the degree to which the average particle diameter of the pigment particles in the pigment dispersion system is prevented from fluctuating is small. In addition, even when the content of the compound represented by the general formula (4) with respect to the compound represented by the general formula (1) exceeds 40% by weight, the average particle size of the pigment particles in the pigment dispersion varies. The degree to which it is suppressed becomes small.

  In the pigment dispersion system according to the present invention, two or more kinds of combinations of these compounds may be used for the compounds represented by the general formulas (2), (3), and (4).

  In the pigment dispersion according to the present invention, the compound represented by the general formula (2), (3), and / or (4) is used in combination with the compound represented by the general formula (1). The dispersibility of the pigment particles in can be improved.

  The pigment dispersion according to the present invention may further include at least one additive selected from the group consisting of water-soluble organic solvents, surfactants, preservatives, and fungicides. A pigment capable of dissolving necessary organic substances by further including at least one additive selected from the group consisting of water-soluble organic solvents, surfactants, preservatives, and fungicides, in the pigment dispersion system Dispersion systems, pigment dispersion systems that further enhance dispersibility of dispersoids including pigment particles, and pigment dispersion systems having properties resulting from additives such as pigment dispersion systems having antiseptic and fungicidal effects be able to.

  With regard to the water-soluble organic solvent as an additive that can be added to the pigment dispersion according to the present invention, for example, methanol (methyl alcohol), ethanol (ethyl alcohol), 1-propanol (n-propyl alcohol), 2-propano Contains 1 to 4 carbon atoms, such as -l (isopropyl alcohol), 1-butanol (n-butyl alcohol), 2-butanol (sec-butyl alcohol), tert-butyl alcohol, and isobutyl alcohol Alcohols, ethylene glycol, propylene glycol such as 1,2-propanediol, butylene glycol such as 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol, diethylene glycol, triethylene glycol , Thio jig Chole, alkylene glycols having an alkylene group containing 2 to 6 carbon atoms such as hexylene glycol, triols such as glycerin and 1,2,6-hexanetriol, polyethylene glycol and polypropylene Ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) obtained by dehydration condensation of polyalkylene glycols such as glycol, the above alcohols and the above alkylene glycols, triols or polyalkylene glycols Lower alkyl ethers of polyhydric alcohols (including monoether derivatives and diether derivatives) such as ethers and triethylene glycol monomethyl (or ethyl) ethers, tetrahydrofurans And ethers such as dioxane, amide compounds such as dimethylformamide and dimethylacetamide, ketones such as acetone and methyl ethyl ketone, ketone alcohols such as diacetone alcohol, monoethanolamine, diethanolamine, and triethanol Examples include alkanolamines such as amines, pyrrolidone derivatives such as 2-pyrrolidone and N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.

  Among the above water-soluble organic solvents, it is preferable to use a polyhydric alcohol such as diethylene glycol or a lower alkyl ether of a polyhydric alcohol such as triethylene glycol monomethyl (or ethyl) ether.

  The content of the additive contained in the pigment dispersion according to the present invention is preferably 0% by weight or more and 50% by weight with respect to the total amount of the pigment dispersion.

  Further, regarding the surfactant as an additive that can be added to the pigment dispersion according to the present invention, for example, a known nonionic surfactant such as isopropyl alcohol, a cationic surfactant, an anion. An ionic surfactant or an amphoteric surfactant.

  Furthermore, with regard to preservatives and fungicides as additives that can be added to the pigment dispersion according to the invention, for example, sodium benzoate, potassium sorbitanate, thiabendazole, benzimidazole, siabendazole, thiazosulfamide And known antiseptics and fungicides such as pyridine thiol oxide.

  The pigment dispersion system according to the present invention is a liquid, and can be used for, for example, general ink (recording liquid) and an ink stock solution. In particular, the pigment dispersion system according to the present invention can be suitably used as an inkjet ink. When the pigment dispersion system according to the present invention is used as an inkjet ink, the pigment dispersion system according to the present invention includes at least one of the above additives in addition to the pigment, the dispersant represented by the general formula (1), and water. Preferably one is included.

  The pigment dispersion according to the present invention comprises a pigment, a dispersant represented by the general formula (1), water, and a mixture of additives as necessary, such as a sand mill, a pearl mill, a dyno mill, a ball mill, a roll mill, a nanomizer, a homogenizer, Is obtained by dispersing the pigment particles in a dispersion medium containing water. When the pigment dispersion system according to the present invention is obtained as an inkjet ink, the pigment, the dispersant represented by the general formula (1), water, and, if necessary, a mixture of additives are stirred and mixed. The obtained pigment dispersion system is filtered through a filter, or is removed from the pigment dispersion system by a method such as applying to a centrifugal separator, and the pigment dispersion system is further degassed as necessary. Ink can be obtained. In the case of using the compound represented by the general formula (2), (3), and / or (4) together with the dispersant represented by the general formula (1) in the pigment dispersion system according to the present invention, The pigment, the dispersant represented by the general formula (1), water, and optionally a mixture of additives can be added when stirring. However, when the pigment dispersion according to the present invention is obtained as an ink jet ink, the mixture of the pigment, the dispersant represented by the general formula (1), water, and, if necessary, the additive is stirred, and then the general formula The compound represented by (2), (3) and / or (4) may be added to the pigment dispersion.

  The present invention can provide a pigment dispersion system in which the average particle size of pigment particles is further reduced. Further, in the pigment dispersion system according to the present invention, even when the pigment dispersion system is stored, fluctuations in the average particle diameter of the pigment particles can be reduced. Thereby, when the pigment dispersion system according to the present invention is used for ink jet ink, the ink can be stably ejected from the nozzle for ejecting ink. In addition, according to the present invention, it is possible to provide a pigment dispersion system excellent in light resistance and color tone clarity in a pigment dispersion receiver such as paper and film. Furthermore, the pigment dispersion according to the present invention can be efficiently produced in a short time.

  The above-described pigment dispersion is accommodated in a pigment dispersion container. That is, according to the present invention, a pigment dispersion containing body in which the pigment dispersion according to the present invention is housed can be provided. When an image such as printing is formed on a pigment dispersion receiver such as paper and film using the image forming apparatus and the pigment dispersion system according to the present invention, the pigment dispersion container is preferably an image. It is detachable from the forming apparatus. For example, when the pigment dispersion system according to the present invention is used as an ink for an image forming apparatus such as a printer, the pigment dispersion system container is an ink cartridge that is detachable from the image forming apparatus. When the pigment dispersion system container is detachable from the image forming apparatus, the pigment dispersion system according to the present invention can be easily installed and replaced in the image forming apparatus.

  In addition, according to the present invention, an image forming method for forming a desired image on a pigment dispersion receiver using the pigment dispersion system according to the present invention, and a pigment dispersion receptor using the pigment dispersion system according to the present invention. An image forming body on which a desired image is formed can be provided.

  The image forming method according to the present invention preferably includes discharging the pigment dispersion system according to the present invention from the image forming apparatus to a pigment dispersion system receiver. That is, the pigment dispersion system is ejected to the receiver by an ink jet method, and a desired image including printing is formed on the receiver. When an image is formed on a receptor by discharging the pigment dispersion according to the present invention from the image forming apparatus to the pigment dispersion receiver, desired images can be formed on various types of receivers.

  An image forming apparatus for using the ink jet method is an ink jet printer. When the image forming apparatus is an ink jet printer, a desired image can be formed on the receptor using a simple mechanism. In particular, in an inkjet printer, since a mechanism for feeding a receiver such as paper is simple, there are few troubles related to feeding of the receiver.

  Examples of such an ink jet printer include a continuous jet type or an on-demand type ink jet printer. In particular, an on-demand type ink jet printer can eject a pigment dispersion system as a necessary amount of ink when necessary. Examples of such on-demand type ink jet printers include piezo type, thermal ink jet type, bubble jet (registered trademark) type, and electrostatic type printers. Among these ink jet printers, it is preferable to use a piezoelectric or thermal ink jet printer. When a piezo ink jet printer is used as an image forming apparatus, various types of pigment dispersion systems can be used as ink ejected from the ink jet printer, and the amount of pigment dispersion system ejected from the image forming apparatus is complicated. It can also be controlled. In addition, when a thermal ink jet printer is used as an image forming apparatus, the number of nozzles that discharge a pigment dispersion system as ink can be easily increased, and as a result, the speed of forming an image on a receptor is improved. be able to.

  Hereinafter, the present invention will be described in more detail based on examples. In the following examples, the number of parts represents part by weight.

(Example 1)
Formula 1
Pigment Red 122 30 parts (FASTOGEN SUPER MAGENTA RG manufactured by Dainippon Ink, Inc.)
8 oxyethylene 40mol adduct 22.5 parts of hydroxy quinoline (formula ₍₁₎ is represented by _{A-O (CH 2 CH 2} O) n -H, A is a 8-quinolinyl group, an n is 40 Some compounds)
147.5 parts of ion-exchanged water A mixture (A) having the composition shown in Formula 1 and a Teflon (registered trademark) -coated stirrer were placed in a 500 ml beaker, and the mixture (A) was stirred for 3 hours. Next, zirconia balls having a diameter of 0.3 mm in a dyno mill (KDL-A type 0.3L batch type glass container set manufactured by Shinmaru Enterprise Co., Ltd.) were used for the stirred processed mixture (A), and 4 A time dispersion treatment was performed to obtain a pigment dispersion (A) in which the average particle size of the pigment particles was 14.3 nm (measured value with Microtrac UPA150 manufactured by Nikkiso Co., Ltd.).

(Example 2)
In Example 1, the composition of the mixture (A) was changed to the composition shown in Formula 2 below, and the time for dispersion treatment was changed to 5 hours. A 1 nm pigment dispersion (B) was obtained.

Formula 2
Pigment Blue 15: 3 30 parts (LIONOL BLUE FG-7351 manufactured by Toyo Ink Manufacturing Co., Ltd.)
Represented by 8-oxyethylene 50mol adduct 22.5 parts of hydroxy quinoline (formula _{(1) A-O (CH} 2 CH 2 O) n -H, wherein A is 8-quinolinyl radical, n is 50 Some compounds)
147.5 parts of ion exchange water (Example 3)
In Example 1, the composition of the mixture (A) was changed to the composition shown in Formula 3 below, and the time required for the dispersion treatment was changed to 2 hours. A 3 nm pigment dispersion (C) was obtained.

Formula 3
Pigment Yellow 74 30 parts (Yellow Seika Kogyo Co., Ltd. Yellow No43)
8 oxyethylene 40mol adduct 22.5 parts of hydroxy quinoline (formula ₍₁₎ is represented by _{A-O (CH 2 CH 2} O) n -H, A is a 8-quinolinyl group, an n is 40 Some compounds)
147.5 parts of ion exchange water (Example 4)
In Example 1, the composition of the mixture (A) was changed to the composition shown in Formula 4 below, and the time required for the dispersion treatment was changed to 2 hours. A 3 nm pigment dispersion (D) was obtained.

Formula 4
30 parts of pigment violet 19 (CFR-311 manufactured by Dainichi Seika Kogyo Co., Ltd.)
Represented by 8-oxyethylene 30mol adduct 22.5 parts of hydroxy quinoline (formula _{(1) A-O (CH} 2 CH 2 O) n -H, wherein A is 8-quinolinyl radical, n is 50 Some compounds)
147.5 parts of ion exchange water (Example 5)
In Example 1, the average particle size was changed in the same manner as in Example 1 except that the composition of the mixture (A) was changed to the composition shown in Formula 5 below and the time for dispersion treatment was changed to 3.5 hours. A 14.1 nm pigment dispersion (E) was obtained.

Formula 5
Pigment Red 122 30 parts (FASTOGEN SUPER MAGENTA RG manufactured by Dainippon Ink, Inc.)
8 oxyethylene 40mol adduct 22.5 parts of hydroxy quinoline (formula ₍₁₎ is represented by _{A-O (CH 2 CH 2} O) n -H, A is a 8-quinolinyl group, an n is 40 Some compound)
Heptaethylene glycol mono (5- tridecyl) 0.2 parts ether (formula _{^{(2) R 1 - (A}} 1) is represented by m -OH, ^{R 1} is a branched alkyl group of 10 carbon atoms, ^{A 1} is A compound which is an oxyethylene unit and m is 7)
Ion-exchanged water 147.3 parts (Example 6)
In Example 1, the average particle size was changed in the same manner as in Example 1 except that the composition of the mixture (A) was changed to the composition shown in Formula 6 below and the time for dispersion treatment was changed to 3.5 hours. A 14.4 nm pigment dispersion (F) was obtained.

Formula 6
Pigment Red 122 30 parts (FASTOGEN SUPER MAGENTA RG manufactured by Dainippon Ink, Inc.)
8 oxyethylene 40mol adduct 22.5 parts of hydroxy quinoline (formula ₍₁₎ is represented by _{A-O (CH 2 CH 2} O) n -H, A is a 8-quinolinyl group, an n is 40 Some compounds)
Dioctylsulfosuccinate Na 0.2 part (general formula (3)
H
｜
_{^{M 1 O 3 S-C-}} COOR 2
｜
H ₂ C-COOR ³
A compound in which M ¹ is Na and both R ² and R ³ are branched alkyl groups having 8 carbon atoms)
Ion-exchanged water 147.3 parts (Example 7)
In Example 1, the average particle size was changed in the same manner as in Example 1 except that the composition of the mixture (A) was changed to the composition shown in Formula 7 below and the time for dispersion treatment was changed to 3.5 hours. A 14.5 nm pigment dispersion (G) was obtained.

Formula 7
Pigment Red 122 30 parts (FASTOGEN SUPER MAGENTA RG manufactured by Dainippon Ink, Inc.)
8 oxyethylene 40mol adduct 22.5 parts of hydroxy quinoline (formula ₍₁₎ is represented by _{A-O (CH 2 CH 2} O) n -H, A is a 8-quinolinyl group, an n is 40 Some compound)
Polyoxyethylene (3) alkyl (C13) ether acetate 0.2 part (general formula (4) R ⁸ O— (A ² ) _n —CH ₂ COOM ² , R ⁸ is a straight chain having 13 carbon atoms A compound which is an alkyl group, A ⁴ is an oxyethylene unit, n is 3, and M ² is Na)
Ion-exchanged water 147.3 parts (Comparative Example 1)
A pigment dispersion (H) having an average particle diameter of 78.5 nm was obtained in the same manner as in Example 1 except that the composition of the mixture (A) was changed to the composition shown in the following formulation 8 in Example 1.

Formula 8
Pigment Red 122 30 parts (FASTOGEN SUPER MAGENTA RG manufactured by Dainippon Ink, Inc.)
Polyoxyethylene alkyl ether phosphate 22.5 parts (Plysark A2198 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
147.5 parts of ion-exchanged water Using the obtained pigment dispersions (A) to (H), inks were prepared according to the ink formulation shown below, the inks were stirred for 30 minutes, and then the pore diameter was 0.8 μm. Inkjet inks (a) to (h) were obtained by filtering through a membrane filter and vacuum degassing.

Ink formulation One of pigment dispersions (A) to (H) 40.00 parts Glycerol 7.50 parts Diethylene glycol 22.50 parts 2-pyrrolidone 3.00 parts Polyoxyethylene (3) alkyl (C13) ether sodium acetate 0 .45 parts distilled water 76.55 parts The obtained pigment dispersions (A) to (H) and the inkjet inks (a) to (h) were subjected to a high-temperature storage stability test at 70 ° C for 7 days. The average particle size of the pigment particles before and after the high temperature storage stability test was measured.

  Table 1 shows the measurement results regarding the average particle diameter of the pigment particles in the pigment dispersions (A) to (H).

表１に示すように、顔料分散液（Ａ）〜（Ｇ）における顔料の粒子の平均粒径は、高温保存性試験の前後のいずれにおいも、顔料分散液（Ｈ）における顔料の粒子の平均粒径よりも顕著に小さいことが確認できた。また、顔料分散液（Ａ）〜（Ｇ）における顔料の粒子の平均粒径に関する高温保存性試験の前後における変動は、顔料分散液（Ｈ）における顔料の粒子の平均粒径に関する高温保存性試験の前後における変動よりも顕著に小さいことも確認できた。

As shown in Table 1, the average particle diameter of the pigment particles in the pigment dispersions (A) to (G) is the average of the pigment particles in the pigment dispersion (H) before and after the high-temperature storage stability test. It was confirmed that it was significantly smaller than the particle size. Moreover, the fluctuation | variation before and after the high temperature preservability test regarding the average particle diameter of the pigment particles in the pigment dispersion liquids (A) to (G) is a high temperature preservability test regarding the average particle diameter of the pigment particles in the pigment dispersion liquid (H) It was also confirmed that the fluctuation was significantly smaller than the fluctuation before and after.

  Table 2 shows the measurement results regarding the average particle diameter of the pigment particles in the inkjet inks (a) to (h).

表２に示すように、インクジェット用インク（ａ）〜（ｇ）における顔料の粒子の平均粒径は、高温保存性試験の前後のいずれにおいも、インクジェット用インク（ｈ）における顔料の粒子の平均粒径よりも顕著に小さいことが確認できた。また、インクジェット用インク（ａ）〜（ｇ）における顔料の粒子の平均粒径に関する高温保存性試験の前後における変動は、インクジェット用インク（ｈ）における顔料の粒子の平均粒径に関する高温保存性試験の前後における変動よりも顕著に小さいことも確認できた。

As shown in Table 2, the average particle diameter of the pigment particles in the inkjet inks (a) to (g) is the average of the pigment particles in the inkjet ink (h) both before and after the high temperature storage stability test. It was confirmed that it was significantly smaller than the particle size. Moreover, the fluctuation | variation before and after the high temperature preservability test regarding the average particle diameter of the pigment particles in the inkjet inks (a) to (g) is a high temperature preservability test regarding the average particle diameter of the pigment particles in the inkjet ink (h). It was also confirmed that the fluctuation was significantly smaller than the fluctuation before and after.

  In addition, using a piezoelectric inkjet printer EM-930C manufactured by EPSON and a thermal inkjet printer Desk Jet 880C manufactured by HP, printing is performed on paper with the inks (a) to (h) after the high temperature storage stability test. The degree of nozzle clogging (ink ejection stability) due to the ink ejected from the nozzles provided in each printer was evaluated.

  Table 2 also shows the evaluation results regarding the ejection stability of the inkjet inks (a) to (h) at the nozzles of the respective printers. In Table 2, ◯ indicates that the ejection stability is high and there is no ink clogging in the nozzle head, and x indicates that the ejection stability is low and ink clogging is present in the nozzle head. Indicates that

  As shown in Table 2, in both the piezo-type inkjet printer and the thermal-type inkjet printer, the ejection stability of the inkjet inks (a) to (g) is high, and the ink is clogged in the nozzle head. I couldn't see it. On the other hand, the inkjet ink (h) had low ejection stability in any printer, and ink clogging was observed in the nozzle head.

  Although the embodiments of the present invention have been specifically described above, the present invention is not limited to these embodiments, and these embodiments of the present invention depart from the spirit and scope of the present invention. And can be changed or modified.

  The present invention relates to a pigment dispersion system in which the average particle size of the pigment particles is further reduced, a pigment dispersion container containing the pigment dispersion system, an image forming body formed using the pigment dispersion system, and the The present invention can be applied to an image forming method for forming an image using a pigment dispersion system.

Claims (25)

In a pigment dispersion comprising a pigment, a dispersant, and water,
The dispersant is represented by the general formula (1).
_{A-O (CH 2 CH 2} O) n -H
A compound represented by
A is a monovalent group of substituted or unsubstituted quinoline or a monovalent group of substituted or unsubstituted isoquinoline,
n is an integer of 10 or more and 100 or less, a pigment dispersion system.   The pigment dispersion according to claim 1, wherein A is an 8-quinolinyl group.   3. The pigment dispersion system according to claim 1, wherein n is 40. General formula (2)
_{^{R 1 - (A 1) m}} -OH
A compound represented by the formula:
R ¹ is an alkyl group having 8 to 14 carbon atoms,
A ¹ is a divalent group containing at least ^one of an oxyethylene unit and an oxypropylene unit;
The pigment dispersion system according to any one of claims 1 to 3, wherein m is an integer of 3 to 16.   The pigment dispersion according to claim 4, wherein the content of the compound represented by the general formula (2) with respect to the compound represented by the general formula (1) is 0.001 wt% or more and 40 wt% or less. system. General formula (3)
H
｜
_{^{M 1 O 3 S-C-}} COOR 2
｜
H ₂ C-COOR ³
A compound represented by the formula:
R ² and R ³ are each an alkyl group having 1 to 20 carbon atoms,
M ¹ is H, Li, Na, K, or N ⁺ R ⁴ R ⁵ R ⁶ R ⁷ ;
R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, and a 3-hydroxypropyl group. Item 6. The pigment dispersion system according to any one of Items 1 to 5.   The pigment dispersion according to claim 6, wherein the content of the compound represented by the general formula (3) with respect to the compound represented by the general formula (1) is 0.001 wt% or more and 40 wt% or less. system. General formula (4)
^{_{R 8 O- (A 2) n}} -CH 2 COOM 2
A compound represented by the formula:
R ⁸ is an alkyl group having 1 to 20 carbon atoms,
A ² is a divalent group containing at least one of an oxyethylene unit and an oxypropylene unit;
n is an integer of 1-12.
M ² is H, Li, Na, K, or N ⁺ R ⁹ R ¹⁰ R ¹¹ R ¹² ,
R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are each selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, and a 3-hydroxypropyl group. Item 8. The pigment dispersion system according to any one of Items 1 to 7.   The pigment dispersion according to claim 8, wherein the content of the compound represented by the general formula (4) with respect to the compound represented by the general formula (1) is 0.001 wt% or more and 40 wt% or less. system.   The pigment dispersion system according to any one of claims 1 to 9, wherein the pigment is Pigment Yellow 74.   The pigment dispersion system according to any one of claims 1 to 9, wherein the pigment is Pigment Red 122 and / or Pigment Violet 19.   The pigment dispersion according to claim 1, wherein the pigment is β-type phthalocyanine copper.   The pigment dispersion system according to any one of claims 1 to 9, wherein the pigment is carbon black.   The pigment dispersion according to any one of claims 1 to 13, further comprising at least one additive selected from the group consisting of a water-soluble organic solvent, a surfactant, a preservative, and a fungicide. .   The pigment dispersion system according to any one of claims 1 to 14, wherein the content of the dispersant with respect to the pigment is 6.25 wt% or more and 50 wt% or less.   The pigment dispersion system according to any one of claims 1 to 15, wherein an average particle diameter of the pigment particles is 10 nm or more and 200 nm or less.   The pigment dispersion system according to any one of claims 1 to 16, wherein the concentration of the pigment is 1 wt% or more and 50 wt% or less.   A pigment dispersion container containing the pigment dispersion according to any one of claims 1 to 17.   The pigment dispersion container according to claim 18, wherein the pigment dispersion container is detachable from the image forming apparatus.   An image forming body, wherein an image is formed on a receiver using the pigment dispersion system according to any one of claims 1 to 17.   An image forming method comprising forming an image on a receptor using the pigment dispersion system according to claim 1.   The image forming method according to claim 21, further comprising discharging the pigment dispersion system from the image forming apparatus to the receiver.   The image forming method according to claim 22, wherein the image forming apparatus is an ink jet printer.   The image forming method according to claim 23, wherein the ink jet printer is a piezo ink jet printer.   The image forming method according to claim 23, wherein the ink jet printer is a thermal ink jet printer.