JP2014058617A - Inkjet recording ink and recording device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet ink achieving all of ink storage property, picture quality and discharge property by selecting and using a specified combination of a dispersant species to be used and an additive species, particularly an additive species for controlling surface tension, and thereby to solve conventional problems about difficulty in achieving all of ink storage property, picture quality and discharge property.SOLUTION: An inkjet recording ink is provided, comprising at least water, a pigment and an organic solvent, in which the pigment is dispersed by use of a nonionic dispersant. The ink further comprises an anionic surfactant, and a linear block copolymer in which dimethyl polysiloxane and polyalkylene oxide are alternately and repeatedly bonded.

Description

  The present invention relates to an ink jet recording ink and an ink jet recording.

The ink jet recording method has an advantage that it is easy to make full color because the process is simpler than other various recording methods, and a high-resolution image can be obtained even with an apparatus having a simple configuration.
In recent years, demands for image quality, hue, saturation, gloss, durability (scratch resistance, marker resistance, etc.) have become more stringent as the speed of OA printers and the improvement of image quality improvement technology. Yes.
In order to improve image quality on plain paper, it is effective to improve the color developability by reducing the surface tension of the ink and increasing the wettability to plain paper. In order to improve the durability of the image, it is effective to add a water-insoluble resin.

  For example, Patent Document 1 proposes two sets of self-dispersing ink and silicone oil-containing ink. However, inks such as this proposal have a problem that they are poor in quick-drying and have a large dependency on the paper type of scratch resistance and marker resistance.

  Patent Document 2 proposes an ink containing polymer fine particles, a water-insoluble or hardly soluble colorant, a water-soluble organic solvent, and a fluorine-based surfactant. However, the low surface tension ink containing the fluorine-based surfactant as in this proposal has a problem that the nozzle plate is easily wetted and it is difficult to ensure ejection stability.

  Patent Document 3 proposes an ink containing a water-soluble solvent, a coloring material, water, and a polymer containing an alkylene oxide part, an aromatic ring part, and a carboxyl part in at least the same molecule. The document also discloses “liquid-repellent treatment around the discharge port” and “contains a silicone surfactant, a fluorosurfactant, etc.”. However, this proposal does not describe any type of silicone surfactant, and it is difficult to ensure ink repellency with a low surface tension ink containing a fluorosurfactant. is there.

  Patent Document 4 proposes an aqueous dispersion for inkjet recording containing a self-dispersing pigment, polymer particles, and a compound having a polysiloxane skeleton, and an aqueous ink containing the aqueous dispersion. However, the surface tension of the proposed ink is 25 mN / m to 50 mN / m, which is not intended for low surface tension ink.

  In Patent Document 5, in order to reduce the surface tension of the inkjet ink and improve the color developability by increasing the wettability to the recording medium, a silicone resin is included in the ink repellent layer of the nozzle plate in the inkjet nozzle. Has proposed. According to this proposal, it is possible to improve the color development of the ink. However, as another requirement of the ink repellent layer, not only the initial ink repellency but also the machine by wiping etc. due to the speeding up of the printer and the increased use frequency. Excellent in mechanical durability. In the conventional ink, although the initial ink repellency can be ensured, when continuous printing is performed, the dried ink adheres to the ink repellent layer, causing a decrease in ink repellency.

  Patent Document 6 proposes an ink containing at least one fluorine-based surfactant and / or silicone-based surfactant as water, a water-soluble organic solvent, a water-dispersible resin, a pigment, and a surfactant. However, there is no mention of fixing to the ink repellent layer.

Further, Patent Document 7 proposes a surfactant type ink containing a silicone oil that prevents sticking to the ink repellent layer. However, since it is a low surface tension ink containing a fluorinated surfactant, foaming is not possible. It becomes an easy prescription and becomes a problem when performing initial filling and continuous printing.
Actually, the proposed formulation does not balance storage stability, image density, excess resistance, dischargeability, and initial filling property.

  An object of the present invention is to solve the above-mentioned problem. Conventionally, it has been difficult to achieve both ink storage stability, image quality, and ejection properties. An object of the present invention is to provide an ink-jet ink that is compatible with ink storage stability, image quality, and ejection performance by selectively using a specific combination with an additive species.

Means for solving the problems include the following. That is, the above problem is solved by the following means of the present invention.
(1) “In an inkjet recording ink containing at least water, a pigment, and an organic solvent, the pigment is a pigment dispersed using a nonionic dispersant, and further, an anionic surfactant, dimethylpolysiloxane And a linear block copolymer in which polyalkylene oxide is alternately and repeatedly bonded.
(2) “The ink jet recording ink according to item (1), wherein the anionic surfactant is a dioctylsulfosuccinate Na salt”.
(3) “The ink-jet recording ink according to item (2), wherein the dioctylsulfosuccinate Na salt has a weight-based content of 0.001 or more and 0.1 or less with respect to pigment 1.”
(4) “Ink jet according to any one of (1) to (3) above, wherein at least one of the materials represented by the following general formula (1) is used as the nonionic dispersant: Recording ink;

（式中、Ｒは炭素数１〜２０のアルキル基、アリル基、アラルキル基を表し、ｌは０〜の整数を表し、ｎは平均繰返し単位を表わす２０〜２００の整数を表す。）。」

(In the formula, R represents an alkyl group having 1 to 20 carbon atoms, an allyl group, or an aralkyl group, l represents an integer of 0 to n, and n represents an integer of 20 to 200 representing an average repeating unit). "

(5) “The inkjet recording ink according to item (4), wherein the nonionic dispersant is POE (n = 40) β-naphthyl ether”.
(6) The inkjet-use as described in any one of (1) to (5) above, wherein the weight basis of the nonionic dispersant is 0.01 or more and 2.0 or less with respect to pigment 1. Recording ink. "
(7) “The ink for inkjet recording according to any one of items (1) to (6), further comprising an anionic self-emulsifying ether polyurethane resin”.
(8) “An ink jet cartridge comprising the ink jet recording ink according to any one of items (1) to (7)”.
(9) “An ink jet recording apparatus comprising a head of a type that performs recording by discharging the ink jet recording ink according to any one of (1) to (7).”
(10) “In a method for producing an inkjet recording ink containing at least water, a pigment, and an organic solvent, an organic pigment is dispersed in a pigment dispersion dispersed using at least a pigment, water, an anionic surfactant, and a nonionic dispersant. A method for producing an inkjet recording ink, comprising a step of mixing a solvent, a linear block copolymer in which dimethylpolysiloxane and polyalkylene oxide are alternately and repeatedly bonded.

As will be understood from the following detailed and specific description, a specific combination of the dispersant type used for the black pigment ink and the color pigment ink and the additive type, particularly the surface tension adjusting additive type is selected. Thus, it is possible to provide a pigment ink, a recording apparatus, and a recording method in which the storage stability, the discharge property, and the image quality are compatible.
In a low surface tension ink using a silicone-based additive or a fluorine-based additive, the use of the additive-containing ink tends to induce a problem that the nozzle plate is easily wetted and it is difficult to ensure ejection stability. Even when contributing to lower surface tension of the ink when coexisting in the ink medium liquid, the ink material tends to be hardened and solidified in the vicinity of the nozzle outlet after the medium liquid evaporation, but surprisingly in the present invention Such a tendency is remarkably alleviated because an additive having a specific structure is compatible with a specific dispersant or an aqueous liquid medium.

It is a figure which shows one example of the inkjet recording device of this invention used also in the Example. It is a schematic diagram for demonstrating the internal structure and operation | movement of the inkjet recording device shown by FIG. It is the schematic which shows an example of the ink bag (241) of the example of the ink cartridge of this invention. FIG. 4 is a schematic view showing an ink cartridge (200) in which the ink bag (241) of FIG. 3 is accommodated in a cartridge case (244).

Hereinafter, the present invention will be described in detail and specifically.
As described above, the present invention relates to an inkjet recording ink containing at least water, a pigment, and an organic solvent, wherein the pigment is a pigment dispersed using a nonionic dispersant, and further, an anionic surfactant. And a linear block copolymer having a specific structure in which dimethylpolysiloxane and polyalkylene oxide are alternately and repeatedly bonded.

[Anionic surfactant]
Examples of the anionic surfactant of the present invention include fatty acid salts, alkyl sulfate esters, alkylaryl sulfonates, alkylnaphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyl diaryl ether disulfonates, alkyl phosphorus Acid salt, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl aryl ether sulfate, naphthalene sulfonic acid formalin condensate, dioctyl sulfosuccinate salt, polyoxyethylene alkyl phosphate ester salt, glycerol borate fatty acid ester, polyoxy Examples thereof include ethylene glycerol fatty acid esters. In particular, dioctyl sulfosuccinate salt can be expected to have good dispersibility even when added in a small amount. The anionic surfactant may be added at the time of dispersion or at the time of ink preparation.

  The weight standard of the diacrylyl sulfosuccinate salt with respect to the pigment of the ink for ink jet recording of the present invention is preferably 0.001 or more and 0.1 or less, more preferably 0.005 to 0.01 with respect to the pigment 1. By setting it in the range of 0.001 to 0.01, an ink liquid having a small average particle diameter and a small standard deviation in the particle size distribution can be provided. If the dispersant for the pigment is less than 0.001, in the case of a pigment having poor wettability, satisfactory saturation cannot be obtained due to the ink liquid having a large average particle diameter and a large standard deviation in the particle size distribution. If it is greater than 0.1, initial filling properties and continuous printing tend to be difficult due to foaming problems.

[Polyether-modified silicone]
The linear block copolymer in which dimethylpolysiloxane and polyalkylene oxide are alternately bonded in the present invention is composed of hydrophobic dimethylpolysiloxane and hydrophilic polyalkylene oxide, and is a nonionic surfactant. However, the chemical structure as an example is shown in the following general formula (2) (this example is for explaining the characteristics of the block copolymer of dimethylpolysiloxane-polyalkylene oxide used in the present invention). Of course, such a block copolymer has unique properties because the main skeleton has a long chain length and a linear structure. . Although it is said to be a polyether-modified silicone oil (hereinafter referred to as a polyether-modified silicone oil), by adding one that focuses on the hydrophilic / lipophilic balance of the polyether-modified silicone oil added to the ink, It has been found that ink sticking to the ink repellent layer can be prevented. In the case of hydrophobic substances, the polyether-modified silicone oil is not sufficiently adsorbed to the water-insoluble resin, causing sticking. On the contrary, when the hydrophilicity becomes strong, the ratio of the hydrophilic part becomes relatively small, so The hydrophilic effect on the surface of the insoluble resin is small, and it still does not exhibit an anti-sticking action.

（式中、aはジメチルシロキサン単位の数を表わす整数、ｂはエトキシ単位の数を表わす整数、ｃはプロピオキシ単位の数を表わす整数、ｄはジメチルシロキサンとポリアルキレンオキサイドからなるブロック単位数を表わす整数であり、ｘは２又は３を表わす。）

(Wherein, a is an integer representing the number of dimethylsiloxane units, b is an integer representing the number of ethoxy units, c is an integer representing the number of propoxy units, and d is the number of block units composed of dimethylsiloxane and polyalkylene oxide. An integer, x represents 2 or 3.)

Moreover, although the reason is not clear, when a polyether-modified silicone oil is used for the one using dioctyl sulfosuccinate Na salt, the effect as foam suppression is also exhibited.
Examples of commercially available products of the polyether-modified silicone include FZ-2203, FZ-2207, FZ-2222, FZ2231 (manufactured by Dow Corning Toray). Of course, the present invention is not limited to these.

[Nonionic dispersant]
The dispersant used for the pigment in the present invention can be appropriately selected according to the type of black and color, but as the nonionic surfactant, polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxy Polyoxyethylene alkyl ethers such as ethylene stearin ether and polyoxyethylene oleyl ether, polyoxyethylene alkyl phenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether, polyoxyethylene α-naphthyl ether, polyoxyethylene β Naphthyl ether, polyoxyethylene monostyryl phenyl ether, polyoxyethylene distyryl phenyl ether, polyoxyethylene alkyl naphth For example, chill ether, polyoxyethylene monostyryl naphthyl ether, polyoxyethylene distyryl naphthyl ether, polyoxyethylene polyoxypropylene block copolymer and the like can be used.
Any dispersant may be used for the pigment in the present invention, but an aqueous pigment ink having a small average particle diameter and a small standard deviation in the particle size distribution by using the material described in the general formula (1). Can be obtained.

（式中、Ｒは炭素数１〜２０のアルキル基、アリル基、アラルキル基を表し、ｌは０〜の整数を表し、ｎは平均繰返し単位を表わす２０〜２００の整数を表す。）
一般式（１）で示される分散剤で、ｎは好ましくは２０以上２００以下、より好ましくは３０以上１００以下である。ｎが２０未満では分散安定性が低下する傾向があり、平均粒径が大きく、又粒度分布に於ける標準偏差の大きいインク液のため満足な彩度が得られない。また、ｎが２００より大きいとインクの粘度が高くなり、インクジェット方式での印字が困難になる傾向がある。ＰＯＥ（ｎ＝４０）（但し平均付加数）βナフチルエーテルが更に好ましい。

(In the formula, R represents an alkyl group having 1 to 20 carbon atoms, an allyl group, or an aralkyl group, l represents an integer of 0 to n, and n represents an integer of 20 to 200 representing an average repeating unit.)
In the dispersant represented by the general formula (1), n is preferably 20 or more and 200 or less, more preferably 30 or more and 100 or less. When n is less than 20, the dispersion stability tends to be lowered, the average particle size is large, and satisfactory chroma cannot be obtained due to the ink standard having a large standard deviation in the particle size distribution. On the other hand, when n is larger than 200, the viscosity of the ink increases, and printing by the ink jet method tends to be difficult. POE (n = 40) (however, average addition number) β naphthyl ether is more preferable.

  As the nonionic dispersant of the present invention, other than the material represented by the general formula (1), a styrenated phenol system (Neugen EA-177, n = 25: estimated from HLB) represented by the following structural formula, etc. Can be used.

  The weight basis of the nonionic dispersant with respect to the pigment of the ink for ink jet recording of the present invention is preferably 0.01 or more and 2.0 or less, more preferably 0.05 to 1.0 with respect to the pigment 1. By setting it in the range of 0.01 to 2.0, an ink liquid having a small average particle diameter and a small standard deviation in the particle size distribution can be provided. When the dispersant for the pigment is less than 0.01, an average liquid particle size is large, and satisfactory saturation cannot be obtained due to the ink liquid having a large standard deviation in the particle size distribution. If it is greater than 2.0, the ink viscosity tends to be too high, and printing by the inkjet method tends to be difficult.

[Urethane resin]
The urethane resin used in the present invention refers to a polymer composed mainly of a polyurethane skeleton whose main chain is a continuous urethane bond. In the present invention, a water dispersible urethane resin is used among the urethane resins. Such a water-dispersible urethane resin is an aqueous dispersion of polyurethane obtained by introducing a hydrophilic component necessary for stable dispersion in water into the main chain of the polyurethane skeleton or by dispersing with an external emulsifier. The body is general, but a self-dispersion type (self-emulsification type) in which a hydrophilic component is introduced into the main chain is more preferable.

  The urethane resin used in the present invention is a reaction between a diisocyanate compound, a diol compound such as polyether diols, polyester diols, and polycarbonate diols, and an acid group-containing diol such as a carboxylic acid group and a sulfonic acid group. Various water-dispersible urethane resins (ester urethane resin, ether urethane resin, carbonate urethane resin, etc.) obtained by the above are suitable. Among these, an anionic self-emulsifying ether urethane resin is particularly preferable.

  Examples of the diisocyanate include aliphatic diisocyanate compounds such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 1,4-cyclohexane diisocyanate, and 4,4′-. Cycloaliphatic diisocyanate compounds such as dicyclohexylmethane diisocyanate, aromatic aliphatic diisocyanate compounds such as xylylene diisocyanate and tetramethylxylene diisocyanate, aromatic diisocyanate compounds such as toluylene diisocyanate and phenylmethane diisocyanate, modified products of these diisocyanates (carbodiimide, uretdione) Ureitomine-containing metamorphs, etc.).

  Examples of the diol compound include polyether diols such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol, polyethylene adipate, polybutylene adipate, polyneopentyl adipate, and poly-3-methylpentyl. Examples thereof include polyester diols such as adipate, polyethylene / butylene adipate, polyneopentyl / hexyl adipate, polylactone diols such as polycaprolactone diol, and polycarbonate diol. From the viewpoint of storage stability of the ink, a polyether-based, polyester-based, or polycarbonate-based diol compound is preferable, a polyether-based or polycarbonate-based compound is more preferable, and a polyether-based compound is more preferable. Polyether-based and polycarbonate-based materials are not easily altered by hydrolysis in water, so that the storage stability is improved. Examples of the acid group-containing diol include dimethylolacetic acid, dimethylolbutanoic acid, dimethylolpropionic acid, and dimethylolbutyric acid. Particularly preferred is dimethylolbutanoic acid.

  As a method for synthesizing a urethane-based resin, an isocyanate-terminated prepolymer is synthesized in a low-boiling solvent that does not react with an isocyanate group (acetone, etc.), a hydrophilic group is introduced with a diamine, polyol, etc., and then diluted with water and phase-converted. Solution method to obtain polyurethane dispersion by distilling off solvent, prepolymer method in which isocyanate group-terminated prepolymer introduced with hydrophilic group is first synthesized, dispersed in water and chain extended with amine, other hot melt method , A method using a urethane prepolymer as a chain extender in an aqueous emulsifier solution, a step of sulfonating an aromatic ring of a urethane prepolymer having a free isocyanate group obtained from a hydrophobic polyol and an aromatic polyisocyanate. Various methods such as passing through, using blocked isocyanate, etc. That is, the present invention is not particularly limited.

In particular, a urethane-based resin may be synthesized by a prepolymer method, and in this case, a low molecular weight polyhydroxy compound may be used. Examples of the low molecular weight polyhydroxy compound include glycol and alkylene oxide low molar adducts mentioned as raw materials for the above polyester diols, trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane, and alkylene oxide low molar adducts thereof. Is mentioned. In the case of an aqueous urethane resin, a method is generally known in which a urethane prepolymer prepared in an organic solvent phase is phase-inverted and emulsified and further chain-extended in the aqueous phase. In this case, polyamines such as diamine are generally used as chain extenders.
Specifically, the urethane prepolymer is subjected to water extension or di- or triamine extension after neutralizing or neutralizing acid groups derived from dimethylolalkanoic acid. Examples of polyamines used as a chain extender during amine extension usually include diamines and triamines. Specific examples thereof include hexamethylene diamine, isophorone diamine, hydrazine, piperazine and the like. However, it has been found that when a urethane resin using polyamines is used as a chain extender, the storage stability of the recording liquid tends to be poor. This is because the amine-extended urethane resin (polyurethane resin containing a polyurethane urea portion) is likely to be hydrolyzed, and the polyamines generated by the hydrolysis also act as an aggregating agent in the pigment dispersion recording liquid. It is presumed to have a seriously bad influence. The urethane resin can be used in the form of an alkali metal salt such as Li, Na, or K, an organic amine salt such as ammonia, dimethylamine, or (mono, di, tri) ethanolamine. These can be obtained by further neutralizing the urethane resin obtained by the above-mentioned method. The base used in this neutralization can be appropriately selected according to the counter ion of the desired salt, for example, alkylamines such as butylamine and triethylamine, monoethanolamine, diethanolamine, triethanolamine and the like. Inorganic bases such as alkanolamine, morpholine, ammonia, sodium hydroxide and the like can be mentioned. Commercially available resin emulsions include SF460, SF460S, SF420SF110, SF300, SF361 (polyurethane resin emulsion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), W-6020, W-5025, W-5661, W-6010 (polyurethane resin emulsion). , Manufactured by Mitsui Chemicals, Inc.). The acid value of the anionic self-emulsifying ether polyurethane resin is preferably 40 or more and 100 or less.

[Pigment]
The average primary particle size of the carbon black in 10.0nm~30.0nm, BET surface area is 100m ² / g~400m ² / g. The average primary particle diameter of preferably carbon black in 15.0nm~20.0nm, BET surface area is 150m ² / g~300m ² / g.

  Specific examples of carbon black include # 10B, # 20B, # 30, # 33, # 40, # 44, # 45, # 45L, # 50, # 55, # 95, # 260, ## manufactured by Mitsubishi Chemical Corporation. 900, # 1000, # 2200B, # 2300, # 2350, # 2400B, # 2650, # 2700, # 4000B, CF9, MA8, MA11, MA77, MA100, MA220, MA230, MA600, MCF88, etc .; Monarch made by Cabot 120, Monarch 700, Monarch 800, Monarch 880, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, Mogal L, Legal 99R, Legal 250R, Legal 300R, Legal 330R, Legal 400R, Legal 500R and Legal 660R, etc .; Made of plastic Printex A, Printex G, Printex U, Printex V, Printex 55, Printex 140U, Printex 140V, Special Black 4, Special Black 4A, Special Black 5, Special Black 6, Special Black 100, Special Black 250 Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, and the like.

  Examples of magenta pigments include Pigment Red 5, Pigment Red 7, Pigment Red 12, Pigment Red 48 (Ca), Pigment Red 48 (Mn), Pigment Red 57 (Ca), Pigment Red 57: 1, Pigment Red 112, and Pigment Red. 122, Pigment Red 123, Pigment Red 168, Pigment Red 184, Pigment Red 202, Pigment Violet 19, and the like.

  Examples of cyan pigments include 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 60, Bat Blue 4, Bat Blue 60 etc. are mentioned.

  Examples of yellow pigments include 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, Pigment Yellow 180, etc. It is.

[Production method of ink-jet ink, pigment dispersion]
As a method for producing the ink jet recording ink of the present invention, first, a mixture of a pigment and a nonionic dispersant, an anionic surfactant, water or a water-soluble organic solvent as necessary is mixed with a stirring blade, a homogenizer, or a beadless dispersion. A method of premixing with a machine, dispersing with a known dispersing machine such as a sand mill, ball mill, dyno mill, roll mill, nanomizer, homogenizer, etc., and then mixing the pigment dispersion and urethane resin as necessary is desirable. If other materials are mixed before mixing the pigment dispersion and the urethane resin, they may aggregate and thicken.

In addition, as a method for producing the ink jet recording ink of the present invention, a method of mixing a material necessary as an ink with the above dispersion is desirable.
At this time, the mixing order can be either the introduction of the ink material into the dispersion or the introduction of the dispersion into the ink material.
Further, by filtering coarse particles with a pigment dispersion and / or ink with a filter, a centrifugal separator, or the like, it is possible to ensure ink ejection stability.

[Inkjet recording apparatus, recording method, ink cartridge]
An ink cartridge containing the ink jet recording ink of the present invention can be formed, and an ink jet apparatus containing the ink cartridge causes the ink to be ejected from an orifice in accordance with a recording signal to form an image on a recording material. An image formed product can be obtained.
Examples of means for printing using the pigment ink of the present invention include a printing method using the above-described inkjet printer (inkjet printer) having a continuous jet type or on-demand type recording head. Note that examples of the on-demand type include a piezo method, a thermal ink jet method, and an electrostatic method.
As these ink cartridge formation, ink jet apparatus formation, and image formation method, known techniques relating to this technical field such as those described in Japanese Patent Application Laid-Open No. 2000-198958 can be appropriately employed.
In the present invention, the recording medium is preferably used regardless of whether the recording medium is absorbent to an ink composition such as paper or substantially non-absorbable to the ink composition. Specific examples of the recording medium to which the ink jet recording method according to the present invention can be applied include plastic sheets based on polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polysulfone, ABS resin, polyvinyl chloride, brass, iron, aluminum, SUS, a metal surface such as copper or a non-metallic base material, a recording medium that has been subjected to a metal coating process by vapor deposition or the like, a recording medium that has been subjected to water-repellent treatment using paper as a base material, and an inorganic material are baked at a high temperature And a recording medium made of a so-called ceramic material.
Of these, paper is most preferable from the viewpoint of economy and the naturalness of images.

The ink of the present invention can be suitably used for various recording apparatuses using an ink jet recording system, such as an ink jet recording printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like.
The outline of the ink jet recording apparatus used in the examples will be described below.

  The ink jet recording apparatus shown in FIG. 1 has an apparatus main body (101), a paper feed tray (102) for loading paper mounted on the apparatus main body (101), and an image mounted on the apparatus main body (101). A paper discharge tray (103) for stocking the formed paper and an ink cartridge loading section (104) are provided. On the upper surface of the ink cartridge loading section (104), an operation section (105) such as operation keys and a display is arranged. The ink cartridge loading unit (104) has an openable / closable front cover (115) for attaching and detaching the ink cartridge (200). (111) is the upper cover, and (112) is the front surface of the front cover.

In the apparatus main body (101), as shown in FIG. 2, a carriage (133) is mainly composed of a guide rod (131) and a stay (132) which are guide members horizontally mounted on left and right side plates (not shown). It is slidably held in the scanning direction and moved and scanned by a main scanning motor (not shown).
The carriage (133) includes a plurality of recording heads (134) including four inkjet recording heads that discharge ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.

  As an inkjet recording head constituting the recording head (134), a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor, and a temperature change A shape memory alloy actuator using a metal phase change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging ink can be used.

  The carriage (133) is equipped with a sub tank (135) for each color for supplying ink of each color to the recording head (134). The sub tank (135) is supplied with ink according to the ink set of the present invention from the ink cartridge (200) of the present invention loaded in the ink cartridge loading section (104) via an ink supply tube (not shown). To be replenished.

  On the other hand, as a paper feeding unit for feeding the paper (142) stacked on the paper stacking unit (pressure plate) (141) of the paper feed tray (102), 1 sheet (142) is fed from the paper stacking unit (141). Opposite to the half-moon roller [sheet feeding roller (143)] for separating and feeding one sheet at a time, and the sheet feeding roller (143), a separation pad (144) made of a material having a large friction coefficient is provided, and this separation pad (144) is It is biased toward the paper feed roller (143).

  A conveying belt (151) for electrostatically adsorbing and conveying the paper (142) as a conveying unit for conveying the paper (142) fed from the paper feeding unit below the recording head (134). A counter roller (152) for conveying the paper (142) sent from the paper supply unit via the guide (145) between the conveying belt (151) and a paper (substantially vertically upward) ( 142) and a leading guide roller 153 urged toward the conveying belt (151) by the holding member (154). (155) and a charging roller (156) which is a charging means for charging the surface of the conveyor belt (151).

  The conveyance belt (151) is an endless belt, is stretched between the conveyance roller (157) and the tension roller (158), and can circulate in the belt conveyance direction. The transport belt (151) includes, for example, a surface layer serving as a sheet adsorbing surface formed of a resin material having a thickness of about 40 μm without resistance control, for example, a copolymer of tetrafluoroethylene and ethylene (ETFE), It has the same material as the surface layer and a back layer (medium resistance layer, earth layer) that has been subjected to resistance control by carbon. On the back side of the conveyance belt (151), a guide member (161) is arranged corresponding to the printing area by the recording head (134). As a paper discharge unit for discharging the paper (142) recorded by the recording head (134), a separation claw (171) for separating the paper (142) from the transport belt (151), and paper discharge A roller (172) and a paper discharge roller (173) are provided, and a paper discharge tray (103) is arranged below the paper discharge roller (172).

  A double-sided paper feeding unit (181) is detachably attached to the back surface of the apparatus main body (101). The double-sided paper feeding unit (181) takes in the paper (142) returned by the reverse rotation of the transport belt (151), reverses it, and feeds the paper again between the counter roller (152) and the transport belt (151). To do. A manual paper feed unit (182) is provided on the upper surface of the double-sided paper feed unit (181).

  In this ink jet recording apparatus, the sheet (142) is separated and fed one by one from the sheet feeding unit, and the sheet (142) fed substantially vertically upward is guided by the guide (145) and the transport belt (151). ) And the counter roller (152). Further, the leading end is guided by the conveying guide (153) and pressed against the conveying belt (151) by the leading end pressure roller (155), and the conveying direction is changed by about 90 °.

  At this time, the conveyance belt (157) is charged by the charging roller (156), and the paper (142) is electrostatically adsorbed to the conveyance belt (151) and conveyed. Therefore, by driving the recording head (134) according to the image signal while moving the carriage (133), ink droplets are ejected onto the stopped sheet (142) to record one line, and the sheet ( 142), the next line is recorded after a predetermined amount is conveyed. Upon receiving a recording end signal or a signal that the rear end of the paper (142) has reached the recording area, the recording operation is finished and the paper (142) is discharged to the paper discharge tray (103).

When a near-end ink remaining amount in the sub tank (135) is detected, a required amount of ink is supplied from the ink cartridge (200) to the sub tank (135).
In this ink jet recording apparatus, when the ink in the ink cartridge (200) is used up, the casing of the ink cartridge (200) can be disassembled and only the ink bag inside can be replaced. Further, the ink cartridge (200) can supply ink stably even when the ink cartridge (200) is vertically placed and has a front loading configuration. Therefore, even when the upper part of the apparatus main body (101) is closed and installed, for example, even when it is stored in a rack or an object is placed on the upper surface of the apparatus main body (101), the ink The cartridge (200) can be easily replaced.

  Here, an example is described in which the present invention is applied to a serial (shuttle type) ink jet recording apparatus that is scanned by a carriage, but the present invention can be similarly applied to a line type ink jet recording apparatus having a line type head.

[ink cartridge]
Each ink constituting the ink set of the present invention can be accommodated in a container and used as an ink cartridge, and other members appropriately selected as necessary may be attached.
The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, the container has an ink bag formed of an aluminum laminate film, a resin film, etc. Etc. are preferable.

  The ink cartridge will be described with reference to FIGS. Here, FIG. 3 is a schematic view showing an example of the ink bag (241) of the ink cartridge of the present invention, and FIG. 4 is an ink cartridge in which the ink bag (241) of FIG. 3 is accommodated in the cartridge case (244). It is the schematic which shows (200).

As shown in FIG. 3, after filling the ink bag (241) with ink from the ink inlet (242) and exhausting the air remaining in the ink bag, the ink inlet (242) is fused. close up. In use, the needle of the apparatus main body is inserted into the ink discharge port (243) made of a rubber member and supplied to the apparatus. The ink bag (241) is formed of a packaging member such as a non-permeable aluminum laminate film. As shown in FIG. 4, it is usually housed in a plastic cartridge case (244) and used as an ink cartridge (200) detachably attached to various ink jet recording apparatuses.
The ink cartridge of the present invention is particularly preferably used by being detachably mounted on the above-described ink jet recording apparatus of the present invention.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to a present Example. In addition, the number of parts in an Example represents a weight part. Tables 1 to 6 show pigment types, dispersants, resins, and the like. Table 7 shows the evaluation results.
First, various materials used in each example and comparative example are collectively shown.

[Basic preparation of pigment dispersion]
Each of the following formulations was premixed to obtain a mixed slurry. Using a disk-type media mill (UAM type Kotobuki Kogyo Co., Ltd.), 0.015 mm zirconia beads and a filling rate of 70% are used to circulate and disperse to a specific average particle size at a peripheral speed of 6 m / s and a liquid temperature of 10 ° C. After centrifuging coarse particles with a centrifuge (Model 7700 manufactured by Kubota Corporation), the mixture was filtered using a filter having a diameter of 1.2 μm to prepare each pigment dispersion.

<Basic formulation of black pigment dispersion>
Black pigment (pigment type α) 250 parts Nonionic dispersant (dispersant V) 50 parts (ratio: 0.2)
・ Anionic surfactant A 5 parts (ratio: 0.02)
・ Remaining distilled water (total: 1000 parts)

<Basic formulation of yellow pigment dispersion>
・ Yellow pigment (pigment type β) 200 parts ・ Nonionic dispersant (dispersant V) 75 parts (ratio: 0.375)
・ Anionic surfactant A 5 parts (ratio: 0.025)
・ Remaining distilled water (total: 1000 parts)

<Basic formulation of magenta pigment dispersion>
・ Magenta pigment (pigment type γ) 200 parts ・ Nonionic dispersant (dispersant V) 75 parts (ratio: 0.375)
・ Anionic surfactant A 5 parts (ratio: 0.025)
・ Remaining distilled water (total: 1000 parts)

<Basic formulation of cyan pigment dispersion>
-Cyan pigment (pigment type δ) 200 parts-Nonionic dispersant (dispersant V) 75 parts (ratio: 0.375)
・ Anionic surfactant A 5 parts (ratio: 0.025)
・ Remaining distilled water (total: 1000 parts)

[Example 1 (Preparation of black ink No. 1)]
Using the above black pigment dispersion, a pigment ink was prepared according to the following ink formulation, stirred for 30 minutes, filtered through a membrane filter having a pore size of 0.8 μm, vacuum degassed, filtered, and ink No. 1 of Example 1. 1 was obtained.

[Ink formula (same for other pigment inks)]
Pigment 5.0 parts Glycerin 7.5 parts Diethylene glycol 15.0 parts 2-Ethyl-1,3-hexanediol 3.0 parts 2-pyrrolidone 3.0 parts Polyoxyethylene (3) alkyl (C13) ether sodium acetate 5 Part additive 1 0.1 part resin a 2.0 parts distilled water remaining (total: 100 parts)

[Example 2 (Preparation of yellow pigment ink No. 2)]
Using the yellow pigment dispersion, a pigment ink was prepared according to the ink formulation, stirred for 30 minutes, filtered through a membrane filter having a pore size of 0.8 μm, vacuum degassed, filtered, and ink No. 2 of Example 2. 2 was obtained.

[Example 3 (Preparation of magenta pigment ink No. 3)]
Using the above magenta pigment dispersion, a pigment ink was prepared according to the above ink formulation, stirred for 30 minutes, filtered through a membrane filter having a pore size of 0.8 μm, vacuum degassed, filtered, and ink No. 3 of Example 3. 3 was obtained.

[Example 4 (Preparation of cyan pigment ink No. 4)]
Using the above cyan pigment dispersion, a pigment ink was prepared according to the above ink formulation, stirred for 30 minutes, filtered through a membrane filter having a pore size of 0.8 μm, vacuum degassed, filtered, and ink No. 4 of Example 4. 4 was obtained.

[Example 5 (Preparation of black ink pigment No. 5)]
Black pigment ink No. The black pigment ink No. 1 was prepared in the same manner except that the anionic surfactant used in Example 1 was changed to B. 5 (Example 5) was obtained.

[Example 6 (Preparation of yellow pigment ink No. 6)]
Yellow pigment ink No. 2 except that the anionic surfactant used in Example 2 was changed to C. 6 (Example 6) was obtained.

[Example 7 (Preparation of cyan pigment ink No. 7)]
Cyan pigment ink no. In the same manner except that the anionic surfactant used in No. 4 was changed to D, cyan pigment ink No. 4 was used. 7 (Example 7) was obtained.

[Example 8 (Preparation of magenta pigment ink No. 8)]
Magenta pigment ink no. 3 except that the anionic surfactant used in No. 3 was changed to E. 8 (Example 8) was obtained.

[Example 9 (Preparation of black pigment ink No. 9)]
Black pigment ink No. No. 1 was used except that the amount of dioctylsulfosuccinate Na salt used in Example 1 was changed to 0.25 parts (ratio 0.001). 9 (Example 9) was obtained.

[Example 10 (Preparation of black pigment ink No. 10)]
Black pigment ink No. No. 1 was used except that the amount of dioctylsulfosuccinate Na salt used in No. 1 was 25 parts (ratio 0.1). 10 (Example 10) was obtained.

[Example 11 (Preparation of black pigment ink No. 11)]
Black pigment ink No. No. 1 was used except that the amount of dioctyl sulfosuccinate Na salt used in No. 1 was 0.20 parts (ratio 0.0008). 11 (Example 11) was obtained.

[Example 12 (Preparation of black pigment ink No. 12)]
Black pigment ink No. No. 1 was used except that the amount of dioctyl sulfosuccinate Na salt used in No. 1 was 0.26 parts (ratio 0.104). 12 (Example 12) was obtained.

[Example 13 (Preparation of yellow pigment ink No. 13)]
Yellow pigment ink No. 2 except that the nonionic dispersant used in III was changed to III. 13 (Example 13) was obtained.

[Example 14 (Preparation of yellow pigment ink No. 14)]
Yellow pigment ink No. 2 except that the nonionic dispersant used in No. 2 was changed to IV. 14 (Example 14) was obtained.

[Example 15 (Preparation of yellow pigment ink No. 15)]
Yellow pigment ink No. 2 except that the nonionic dispersant used in No. 2 was changed to I. 15 (Example 15) was obtained.

[Example 16 (Preparation of yellow pigment ink No. 16)]
Yellow pigment ink No. 2 except that the nonionic dispersant used in No. 2 was changed to II. 16 (Example 16) was obtained.

[Example 17 (Preparation of magenta pigment ink No. 17)]
Magenta pigment ink no. 3 except that the addition amount of the nonionic dispersant used in No. 3 was 2.0 parts (ratio 0.01). 17 (Example 17) was obtained.

[Example 18 (Preparation of magenta pigment ink No. 18)]
Magenta pigment ink no. 3 except that the amount of the nonionic dispersant used in 400 was 400 parts (ratio 2.0). 18 (Example 18) was obtained.

[Example 19 (Preparation of magenta pigment ink No. 19)]
Magenta pigment ink no. A magenta pigment 19 (Example 19) was obtained in the same manner except that the addition amount of the nonionic dispersant used in No. 3 was changed to 1.5 parts (ratio 0.008).

[Example 20 (Preparation of magenta pigment ink No. 20)]
Magenta pigment ink no. 3 except that the addition amount of the nonionic dispersant used in No. 3 was changed to 401 parts (ratio 2.01). 20 (Example 20) was obtained.

[Example 21 (Preparation of cyan pigment ink No. 21)]
Cyan pigment ink no. The cyan pigment ink no. 21 (Example 21) was obtained. These ink formulations are summarized in Table 6.

[Comparative Example 1 (Preparation of black pigment ink No. 22)]
Black pigment ink No. Black pigment ink No. 1 was used in the same manner except that the dispersant used in 1 was changed to VI. 22 (Comparative Example 1) was obtained.

[Comparative Example 2 (Preparation of Yellow Pigment Ink No. 23)]
Yellow pigment ink No. The yellow pigment ink no. 23 (Comparative Example 2) was obtained.

[Comparative Example 3 (Preparation of magenta pigment ink No. 24)]
Magenta pigment ink no. In the same manner except that the dispersant type used in No. 3 is VI, the magenta pigment ink No. 24 (Comparative Example 3) was obtained.

[Comparative Example 4 (Preparation of Cyan Pigment Ink No. 25)]
Cyan pigment ink no. The cyan pigment ink no. 25 (Comparative Example 4) was obtained.

[Comparative Example 5 (Preparation of black pigment ink No. 26)]
Black pigment ink No. The black pigment ink No. 1 was prepared in the same manner except that the anionic surfactant used in No. 1 was not added. 26 (Comparative Example 5) was obtained.

[Comparative Example 6 (Preparation of yellow pigment ink No. 27)]
Yellow pigment ink No. In the same manner as in Example 2 except that the anionic surfactant used in No. 2 was not added. 27 (Comparative Example 6) was obtained.

[Comparative Example 7 (Preparation of magenta pigment ink No. 28)]
Magenta pigment ink no. 3 except that the anionic surfactant used in No. 3 was not added. 28 (Comparative Example 7) was obtained.

[Comparative Example 8 (Preparation of cyan pigment ink No. 29)]
Cyan pigment ink no. The cyan ink No. 4 was prepared in the same manner except that the anionic surfactant used in No. 4 was not added. 29 (Comparative Example 8) was obtained.

[Comparative Example 9 (Preparation of black pigment ink No. 30)]
Black pigment ink No. In the same manner except that the additive No. 1 used in No. 1 was changed to the additive No. 2, the black pigment ink No. 1 was used. 30 (Comparative Example 9) was obtained.

[Comparative Example 10 (Preparation of yellow pigment ink No. 31)]
Yellow pigment ink No. In the same manner, except that the additive No. 1 used in No. 2 was changed to the additive No. 2, the yellow pigment ink No. 2 was used. 31 (Comparative Example 10) was obtained.

[Comparative Example 11 (Preparation of magenta pigment ink No. 32)]
Magenta pigment ink no. In the same manner except that the additive No. 1 used in No. 3 was changed to the additive No. 2, the magenta pigment ink no. 32 (Comparative Example 11) was obtained.

[Comparative Example 12 (Preparation of Cyan Pigment Ink No. 33)]
Cyan pigment ink no. In the same manner, except that additive No. 1 used in No. 4 was changed to additive No. 2, cyan pigment ink no. 33 (Comparative Example 12) was obtained. These ink formulations are summarized in Table 6.

註（１）；上記表中「添加量はインク１００部当りの量。但し、分散剤量は顔料に対する量比。
註（２）；インク１００部中、他に、グリセリン７．５部、ジエチレングリコール１５．０部、２−エチル−１，３−へキサンジオール３．０部、２−ピロリドン３．０部、ポリオキシエチレン(3)アルキル(C13）エーテル酢酸ナトリウム０．５部を含む。インク１００部中の残部は蒸留水）。

註 (1): In the above table, “the amount added is the amount per 100 parts of ink. However, the amount of the dispersant is the ratio with respect to the pigment.
註 (2); In addition to 100 parts of ink, 7.5 parts of glycerin, 15.0 parts of diethylene glycol, 3.0 parts of 2-ethyl-1,3-hexanediol, 3.0 parts of 2-pyrrolidone, poly Contains 0.5 parts of sodium oxyethylene (3) alkyl (C13) ether acetate. The balance in 100 parts of ink is distilled water).

  Examples 1 to 21 and Comparative Examples 1 to 12 were filled in an ink pack for an ink jet printer IPSiO GX 5000 manufactured by Ricoh Co., Ltd. to prepare an ink cartridge.

  Printing was performed on a PPC paper XEROX 4200 manufactured by Xerox Co., Ltd., and the printed image was measured with an Xrite densitometer. The ejection stability and ink storage stability were also evaluated by the following test methods. Table 7 shows the measurement results.

[Evaluation 1: Image evaluation (saturation of image, solid density)]
The sharpness (saturation) of an image refers to the distance from the origin on the chromaticity diagram by measuring the color of a solid image of the image sample with an Xrite densitometer and plotting it on the chromaticity diagram. More specifically, the values of the following calculation formula (1) are referred to for the a value and the b value on the chromaticity diagram.

[Evaluation criteria]
(Yellow pigment ink saturation)
○: Saturation of 80 or more Δ: Saturation of 75 or more and less than 80 ×: Saturation of less than 75

(Magenta pigment ink saturation)
○: Saturation 70 or more Δ: Saturation 65 or more and less than 70 ×: Saturation 65 or less

(Cyan pigment ink saturation)
○: Saturation 55 or more Δ: Saturation 50 or more and less than 55 ×: Saturation 50 or less

(Black solid density)
○: 1.30 or more Δ: 1.20 or more and less than 1.30 ×: less than 1.20

[Evaluation 2: Discharge stability]
Ricoh's Inkjet Printer IPSiO GX 5000 is placed in a constant temperature and humidity chamber, the environment inside the tank is set to a temperature of 32 ° C and a humidity of 30% RH, and the following print pattern chart is printed continuously for 20 minutes and then printed for 20 minutes. The operation was suspended, and this was repeated 50 times. After a total of 1,000 copies were printed, a nozzle check pattern was applied, and the number of omissions was determined.

(Print pattern chart, evaluation criteria)
In the printing pattern, each ink was printed at a duty of 100% in a chart in which the printing area in the image area is 5% of the printing area of each color in the entire area of the paper. The printing conditions were a recording density of 300 dpi and one-pass printing.
○: No omission △: Within 10 omissions x: More than 10 omissions

[Evaluation 3: Ink storage stability, evaluation criteria]
Each ink was put in a polyethylene container and sealed, and the particle size, surface tension, and viscosity after storage at 70 ° C. for 3 weeks were measured and evaluated according to the rate of change from the initial physical properties as follows.
○: Within 10% Δ: Within 30% ×: Over 50%

[Evaluation 4: Foaming evaluation, evaluation criteria]
10 ml of each ink is put in a predetermined cylinder (L480, φ65 mm, scale 0 to 1,000 ml, scale 10 ml) and heated to a specified temperature (25 ° C.). Next, the air introduction pipe is attached so as to be in contact with the bottom surface of the cylinder, and air is blown in (flow rate 94 ml / min × 5 min). The height of the foam after standing for 10 minutes with the ventilation stopped was evaluated.
○: Within 50 ml height △: Greater than 50 ml height, within 100 ml x: Greater than 100 ml height

Next, the evaluation results in Table 7 will be examined.
Compared to all the Examples and Comparative Examples, in the inkjet recording ink containing at least water, a pigment, and an organic solvent of the present invention, the pigment is a pigment dispersed using a nonionic dispersant, Furthermore, an ink jet recording ink comprising an anionic surfactant, a linear block copolymer in which dimethylpolysiloxane and polyalkylene oxide are alternately and repeatedly bonded is basically the object of the present invention. To achieve.
On the other hand, the comparative example lacking any of the above requirements was inferior in at least one evaluation.
Moreover, in addition to the said requirements, the inkjet recording ink which satisfy | fills also the requirements of the said (2) term-(7) term showed the further preferable result, respectively.
That is, from the comparison results between Examples 1 to 4 and Examples 5 to 8, when dioctyl sulfosuccinate Na salt was used as the anionic surfactant, the foaming evaluation was excellent.
Further, when the content of the dioctylsulfosuccinate Na salt based on the weight of the dioctylsulfosuccinate Na salt is 0.001 or more and 0.1 or less with respect to the pigment 1, the dioctylsulfosuccinate Na salt of Examples 9 to 10 is based on the weight. When the content is 0.001 or more and 0.1 or less with respect to Pigment 1, from the comparison results with Examples 11 to 12, it is superior to the image evaluation and foaming evaluation results of Example 11, and the foaming of Example 12 It was superior to the evaluation result.
Further, Examples 13 to 14 using one of the compound materials represented by the general formula (1) as the nonionic dispersant were more ink than the case of Example 15 based on the result of comparison with Examples 15 to 16. The result of the excellent storage evaluation and the better dischargeability evaluation than in the case of Example 16 was shown.
Further, when the nonionic dispersant was POE (n = 40) β naphthyl ether, the ink storage evaluation of Example 2 was superior to that of Example 15.
Further, when the weight reference amount of the nonionic dispersant is 0.01 or more and 2.0 or less with respect to the pigment 1 in particular, Examples 17 to 18 are more in terms of ink storage evaluation than Example 19. Excellent results were shown, and results superior to Example 20 in terms of evaluation of dischargeability were shown.
Further, when an anionic self-emulsifying type ether polyurethane resin was further contained, for example, Example 4 was superior in ink storage evaluation as compared with Example 21.

  Based on the above results, pigment inks, recording devices and recordings that can be expected to achieve both storage stability, ejection properties, and image quality by defining the types of dispersants and additives used in black pigment inks and color pigment inks. It can be seen that a method can be provided.

(About Fig. 1 and Fig. 2)
DESCRIPTION OF SYMBOLS 101 Main body 102 Paper feed tray 103 Paper discharge tray 104 Ink cartridge loading part 105 Operation part 111 Upper cover 112 Front cover front 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Sub tank 141 Paper placement part 142 Paper 143 Feed roller 144 Separator pad 145 Guide 151 Transport belt 152 Counter roller 153 Transport guide 154 Pressing member 155 Pressure roller 156 Charging roller 157 Transport roller 158 Tension roller 161 Guide member 171 Separating claw 172 Paper discharge roller 173 Paper discharge roller 181 Double-sided feeding Paper unit 182 Manual paper feed unit 200 Ink cartridge (FIGS. 3 and 4)
200 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge case

JP 2010-059401 A JP 2003-226827 A JP 2004-10733 A Japanese Patent Laid-Open No. 2007-154021 JP 2005-138383 A JP 2008-95089 A JP 2009-62519 A

Claims (10)

  In an inkjet recording ink containing at least water, a pigment, and an organic solvent, the pigment is a pigment dispersed using a nonionic dispersant, and further includes an anionic surfactant, dimethylpolysiloxane, and polyalkylene oxide. An ink jet recording ink comprising a linear block copolymer in which are repeatedly bonded alternately.   The inkjet recording ink according to claim 1, wherein the anionic surfactant is a dioctyl sulfosuccinate Na salt.   3. The inkjet recording ink according to claim 2, wherein the dioctylsulfosuccinate Na salt has a weight-based content of 0.001 or more and 0.1 or less with respect to the pigment 1. The inkjet recording ink according to claim 1, wherein at least one of the materials represented by the following general formula (1) is used as the nonionic dispersant.

(In the formula, R represents an alkyl group having 1 to 20 carbon atoms, an allyl group, or an aralkyl group, l represents an integer of 0 to n, and n represents an integer of 20 to 200 representing an average repeating unit.)   The inkjet recording ink according to claim 4, wherein the nonionic dispersant is POE (n = 40) β-naphthyl ether.   6. The inkjet recording ink according to claim 1, wherein the nonionic dispersant has a weight standard of 0.01 or more and 2.0 or less with respect to the pigment 1.   The ink for inkjet recording according to any one of claims 1 to 6, further comprising an anionic self-emulsifying ether polyurethane resin.   An ink jet cartridge containing the ink jet recording ink according to any one of claims 1 to 7.   An ink jet recording apparatus comprising: a head that performs recording by discharging the ink jet recording ink according to any one of claims 1 to 7.   In a method for producing an ink jet recording ink containing at least water, a pigment, and an organic solvent, an organic solvent, dimethylpolysiloxane is added to a pigment dispersion dispersed using at least a pigment, water, an anionic surfactant, and a nonionic dispersant. A method for producing an ink jet recording ink, comprising a step of mixing a linear block copolymer in which siloxane and polyalkylene oxide are alternately and repeatedly bonded to obtain an ink composition.

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