JP2016172803A - Aqueous ink set for inkjet, ink cartridge and inkjet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set capable of increasing a holding amount of a waste ink inside a waste ink tank.SOLUTION: An ink set includes: a black ink containing water, a humectant, a pigment and a polyurethane resin; and a color ink containing water, a compound expressed by a general formula (1), a humectant, a pigment, and a polyurethane resin. The black ink and the color ink have, at 25°C, viscosity of 4-6 mPa.s, and Casson yield value of 0.3 Pa or lower. (R is a C1-20 alkyl group, allyl group or aralkyl group; l is an integer number of 0-7; and n is an integer number of 20-200.)SELECTED DRAWING: None

Description

  The present invention relates to an improved inkjet water-based ink set, an ink cartridge, and an inkjet recording apparatus.

In an inkjet image forming apparatus, a cleaning operation for ejecting an appropriate amount of ink is performed as needed in order to maintain the state of a nozzle for ejecting ink.
The ink ejected at the time of cleaning passes through the tube from the tray, is guided to the waste ink tank, and is absorbed by the absorbent body such as a porous body.
The path from the tray to the waste ink tank is normally open and is in contact with the outside air. Therefore, the ink is dried while passing through the path, and as a result of drying through the path, the ink thickened in the waste ink tank is hardly absorbed by the absorber.

Although the path to the waste ink tank may be sealed, it is necessary to provide an opening / closing mechanism in accordance with the movement of the ink jet head, leading to a decrease in reliability and cost of the apparatus.
So far, the following countermeasures for drying in the waste ink tank have been studied.

In the technique described in Japanese Patent Application Laid-Open No. 2000-141705 in Patent Document 1, the shape of the absorber in the waste ink tank is adjusted to maintain the ink absorbability. However, only by adjusting the shape of the absorber, it is difficult to obtain a sufficient effect depending on the combination with ink.
In the technique described in Japanese Patent Application Laid-Open No. 2008-62430 of Patent Document 2, glycerin is disposed in the waste ink tank and mixing with the ink is attempted to prevent drying in the waste ink tank. Need to be expensive.
In the technique described in Japanese Patent Application Laid-Open No. 2000-198956 of Patent Document 3, the pH of the combined color ink is adjusted to prevent ink aggregation as a countermeasure against the aggregation of self-dispersing carbon. It is often difficult to balance with other parts.
By the way, as an ink for inkjet recording which paid attention to the Casson yield value, Japanese Patent Application Laid-Open No. 2014-37495 discloses a Casson yield value of 5 to 10 Pa · s when viscosity is measured at a shear rate of 1 to 100 l / s. Inkjet plain paper recording inks having a Casson yield value of less than 60 Pa · s when viscosity is measured at a shear rate of 1000 l / s is disclosed. It is explained that it is mainly intended for high-quality image formation on paper.

In the prior art, no proposal has been made focusing on the viscosity of waste ink, particularly the yield value.
On the other hand, a resin may be added to the ink for the purpose of improving the quality of the ink, such as fixing properties, glossiness, and show-through. In such an ink, when the ink starts to dry, the viscosity becomes higher than that in the case where no resin is added, and a phenomenon in which the ink is hardly absorbed by the absorber in the waste ink tank is observed.

  An object of the present invention is to provide an ink set capable of increasing the amount of waste ink retained in a waste ink tank even when the shape of the apparatus or the container is not changed or the cost is not increased. .

The above problem is solved by the “ink set” of the present invention described in the following (1).
(1) “A black ink containing at least water, a wetting agent, a pigment, and a polyurethane resin; at least water, a polyoxyethylene-β-naphthyl ether of the following general formula (1), a wetting agent, a pigment, and a polyurethane resin: An ink set having color inks contained therein,
The black ink and the color ink have a viscosity at 25 ° C. of 4 mPa · s to 6 mPa · s,
An ink set characterized by a Casson yield value of 0.3 Pa or less.

（式中、Ｒは炭素数１〜２０のアルキル基、アリル基またはアラルキル基を表し、ｌは０
〜７の整数を表し、ｎは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, and l is 0.
Represents an integer of -7, and n represents an integer of 20-200. ) "

  With such an ink configuration, even after the ink has flowed down to the waste ink tank, even if the drying of the ink proceeds, the absorption to the ink absorber in the waste ink tank is not hindered. Ink can be held in the tank.

It is a schematic plan view showing an example of an ink cartridge according to the present invention. It is a schematic plan view which shows the modification of the ink cartridge of this invention shown in FIG. 1 is a perspective view of an ink jet recording apparatus in a state where a cover of an ink cartridge loading unit according to the present invention is opened. It is sectional drawing explaining the whole structure of the inkjet recording device of FIG. It is a schematic enlarged view which shows the inkjet head in the inkjet recording device shown in FIG. It is a figure which shows the example of a recovery apparatus which recovers the discharge defect of the inkjet head in the inkjet recording device of this invention.

Hereinafter, the present invention will be described in detail.
As described above, the present invention provides (1) a black ink containing at least water, a wetting agent, a pigment, and a polyurethane resin, at least water, polyoxyethylene-β-naphthyl ether of the following general formula (1), An ink set having a wetting agent, a pigment, and a color ink containing a polyurethane resin,
The black ink and the color ink have a viscosity at 25 ° C. of 4 mPa · s to 6 mPa · s,
An ink set having a Casson yield value of 0.3 Pa or less;

（式中、Ｒは炭素数１〜２０のアルキル基、アリル基またはアラルキル基を表し、ｌは０〜７の整数を表し、ｎは２０〜２００の整数を表す。）。」に係るものである。
が、この「インクセット」は、つぎの（２）〜（３）に記載の「インクセット」の態様を包含し、また本発明は、つぎの（４）および（５）記載の「インクカートリッジ」および「
インクジェット記録装置」をも包含するものであるので、これらについても併せて詳細に説明する。
（２）「 前記ブラックインクに含有される顔料が、前記一般式（１）の化合物により分散された分散型顔料を含むことを特徴とする前記（１）に記載のインクセット。」
（３）「 前記ブラックインクに含有される顔料が、自己分散型顔料を含むこと特徴とする前記（１）に記載のインクセット。」
（４）「 前記（１）乃至（３）のいずれかに記載のインクセット中のインクをそれぞれ容器中に収容してなることを特徴とするインクカートリッジ。
（５）「 前記（１）乃至（３）のいずれかに記載のインクセット中のそれぞれのインクに刺激を付与し、該インクを記録ヘッドから液滴として飛翔させて記録媒体上に画像を記録するインク飛翔手段を有するインクジェット記録装置。」

(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 7, and n represents an integer of 20 to 200). ”.
However, the “ink set” includes the embodiments of the “ink set” described in the following (2) to (3), and the present invention includes the “ink cartridge” described in the following (4) and (5). "and"
Since this also includes an “inkjet recording apparatus”, these will be described in detail.
(2) “The ink set according to (1), wherein the pigment contained in the black ink includes a dispersed pigment dispersed by the compound of the general formula (1).”
(3) The ink set according to (1), wherein the pigment contained in the black ink includes a self-dispersing pigment.
(4) An ink cartridge characterized in that the ink in the ink set according to any one of (1) to (3) is accommodated in a container.
(5) “Stimulation is applied to each ink in the ink set according to any one of (1) to (3), and the ink is ejected as a droplet from the recording head to record an image on the recording medium. Inkjet recording apparatus having ink flying means to perform. "

(Casson yield value)

The Casson yield value in the present invention can be measured using a commercially available apparatus, and an example thereof is shown below.

  In an inkjet image forming apparatus, a waste ink tank for collecting ink scraped from the head surface or ejected ink to eliminate nozzle clogging is used. In the waste ink tank, the color ink and the black ink are mixed and absorbed by the ink absorber. The mixing ratio of the ink absorbed by the ink absorber generally depends on the state of use of the image forming apparatus, but the ratio of color to black ink is about 1: 1. Further, the ratio of the color inks is about the same for each color. Therefore, the physical properties of the ink mixed at the same ratio as the configuration when absorbed by the ink absorber affects the absorbability of the ink with respect to the ink absorber.

[Casson yield value]
(Definition)
The Casson yield value in the present invention is a value defined as follows.
Measurement is performed using a rheometer (MCR301 manufactured by Anton Paar) in an environment of 25 ° C. and 50% RH. At this time, a gap (Gap) is set to 50 μm using a flat plate having a diameter of 5 (cm). The shear stress is measured for a shear rate of 1 to 1000 (1 / s), and the square of the intercept b when the graph is extrapolated so that the square root √D of the shear rate is 0 in the following relational expression (1) is Casson. Yield value.

（ここで、Ｓ：せん断応力、Ｄ：せん断速度、（ａ、ｂは係数））
上記関係式（１）においてせん断速度の平方根√Ｄが０になるようにグラフを外挿したときの切片ｂの２乗が、Ｃａｓｓｏｎ降伏値である。

(Where S: shear stress, D: shear rate, (a and b are coefficients))
In the above relational expression (1), the square of the intercept b when the graph is extrapolated so that the square root √D of the shear rate becomes 0 is the Casson yield value.

(Measuring method)
The Casson yield value in the present invention is measured using a commercially available apparatus. Details are shown below.
The Casson yield value shown in the present invention is measured using a mixed ink in which black ink and the color ink are mixed in an equal mass. In the case of an ink set having a plurality of color inks, either one of the color inks is selected and measured using a mixed ink in which the same amount of black ink is mixed with each other, or a plurality of color inks are mixed with an equal amount of each. Further, the mixed color ink may be measured using a mixed ink obtained by mixing an equal mass with the black ink, and the Casson yield value may be satisfied in any measurement result.

(Ink viscosity)
The viscosity of the ink is a shear rate of 100 (1 / s) when a rheometer is used in an environment of 25 ° C. and 50% RH, and a gap is set to 50 μm on a flat plate having a diameter of 5 (cm). To measure.

The Casson yield value in the present invention needs to be 0.3 Pa or less.
Preferably, it is 0.25 Pa or less and 0.01 Pa or more. When the yield value is higher than 0.3 Pa, the fluidity is lowered, the flow in the waste ink path is insufficient, and the fluid tends to stay, or the diffusion in the waste ink tank and the absorbability to the absorber are lowered.
As the yield value increases, more force is required to move the stationary ink.
In the waste ink tank, only the vibration and gravity of the image forming apparatus itself have a force applied to the ink. Therefore, in order to diffuse the ink into the waste ink tank, it is necessary to lower the yield value.
Further, when the yield value is 0.3 Pa or less, the fluidity around the cleaning blade on the upstream side of the waste ink path is also improved.

The cleaning blade is formed of an elastic member such as urethane rubber, and excess ink adhering to the head surface is wiped off by the edge of the blade. The wiped ink flows on the surface of the blade and is guided to the waste ink path. However, since the amount of wiping is very small, the time that the ink is held on the surface of the cleaning blade is long. If the wiped ink is held for a long time, drying proceeds during that time, and it becomes difficult for the ink to flow from the surface of the cleaning blade. If an ink layer is formed on the surface of the blade, the ink wiping performance of the cleaning blade will be adversely affected. There is a case. In the ink set of the present invention, the viscosity of the undried ink is from 4.0 mPa · s to 6.0 mP · s, so that it does not easily stay on the blade surface, and even when used for a long time, the ink of the cleaning blade is wiped off. Easy to maintain ability.
However, when a pigment is used as the coloring material, the yield value varies due to the interaction between the pigment and the wetting agent.
When it is desired to lower the yield value, it is better to increase the ratio of the wetting agent to the pigment. However, if the amount of the wetting agent is increased too much, the viscosity of the ink increases. In order to obtain the yield value of the dry ink necessary for the present invention, the viscosity of the undried ink is from 4.0 mPa · s to 6.0 mP · s.

In the present invention, the yield value after drying for 48 hours in a petri dish with a diameter of 30 mm in a 50 mm petri dish at 50 ° C. and 10% RH is specified, but the viscosity of the pigment suspension is known as Arrhenius' law. Thus, it expands exponentially with respect to the concentration of the pigment. The change is almost linear, and the yield value during drying can be controlled by controlling the yield value in the above state.
In the ink-jet ink, the Casson yield value can be adjusted to a value to be obtained mainly by appropriately selecting the addition amount and type of the wetting agent. The main function of the wetting agent is to absorb and retain moisture, but if it contains moisture, the viscosity decreases and the viscosity increases as the moisture evaporates. In the state where moisture has disappeared, the viscosity and yield value are determined by the interaction between the wetting agent and non-volatile components such as pigments and resins.
When it is desired to lower the yield value, it is preferable to select a wetting agent having a low viscosity and increase the ratio of the wetting agent having a low viscosity.

  Further, it is preferable to select a wetting agent so that the interaction with the pigment and the resin is low. Further, since the structural viscosity increases and the yield value increases as the amount of non-flowable components such as pigments and resins increases, it is preferable to reduce the addition ratio within a range that does not affect the image quality. When the content (mass basis) of the wetting agent in the ink is 1, the mass of a non-flowable component such as a pigment or resin (a component present as a solid content in the ink in a 25 ° C. environment) is 1 / 3 or less, preferably 1/5 or less. On the other hand, if the ratio is 1/20 or less, the ratio of the wetting agent to the entire ink becomes too high, and the viscosity of the ink is increased.

(ink)
The ink composition of the black ink and color ink of the present invention will be described.
The ink of the present invention contains at least water, a wetting agent, a pigment, and a polyurethane resin, and if necessary, a penetrating agent and other components (pH adjuster, antiseptic / antifungal agent, chelating reagent, rust inhibitor, antioxidant) Agents, ultraviolet absorbers, oxygen absorbers, light stabilizers, etc.).

<Wetting agent>
In the present invention, as described above, a wetting agent (for the purpose of enhancing the diffusion in the waste ink tank and the absorbability to the ink absorber and the purpose of stabilizing the discharge by suppressing the drying of the ink inside the head) Hereinafter, it may be referred to as “water-soluble organic solvent”).
Examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1 , 6-hexanediol, 2-ethyl-1,3-hexanediol, glycerin, 1,2,6-hexanetriol, 1,2,3-butanetriol, 1,2,4-butanetriol, petriol, etc. Polyhydric alcohols, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl Ether, polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N- Nitrogen-containing heterocyclic compounds such as hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, amides such as formamide, N-methylformamide, N, N-dimethylformamide, mono Examples include amines such as ethanolamine, diethanolamine, and triethylamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol, propylene carbonate, and ethylene carbonate.
Among these, 3-methyl-1,3-butanediol, 1,3-butanediol, glycerin, and 2-pyrrolidone are preferable.
The amount of the wetting agent (water-soluble organic solvent) added is preferably 10% by mass or more and less than 40% by mass in the ink.
If it is 10% by mass or more, the effect of suppressing the drying property of the ink becomes high, and the diffusion of ink in the ink tank and the absorption to the absorber are improved. If it is 40% by mass or less, the viscosity of the ink is suppressed, and the ejection from the head is easily stabilized.

<Pigment>
As the pigment, an organic pigment or an inorganic pigment can be used. In addition, although you may contain dye simultaneously for the purpose of color tone adjustment, it is preferable to use in the range which does not deteriorate a weather resistance.
The content of the pigment in the present invention is not uniquely determined because it is appropriately selected depending on the type and color of the pigment, but as an approximate range, the solid content is 2% by mass to 10% by mass with respect to 100% by mass of the total ink. It is about mass%.
If it is less than the above range, the image density at the time of printing will be low, and if it is more than the above range, the viscosity of the ink will be high and the ejection stability will be reduced.

  Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black. Among these, carbon black is particularly preferable. In addition, as said carbon black, what was manufactured by well-known methods, such as a contact method, a furnace method, and a thermal method, is mentioned, for example.

  Examples of the organic pigment include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are more preferable. Examples of the azo pigment include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinofullerone pigments. Examples of the dye chelates include basic dye chelates and acidic dye chelates.

  Examples of the black color include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), oxidation, and the like. Examples thereof include metals such as titanium, organic pigments such as aniline black (CI pigment black 1), and the like.

The black pigment used in the present invention is preferably a pigment dispersion (self-dispersing pigment) having at least one hydrophilic group on the surface and exhibiting water dispersibility in the absence of a dispersant.
When the self-dispersing pigment is used in the present invention, the ink ejection stability is improved. The reason is not clear, but it is presumed that sticking at the tip of the inkjet nozzle is reduced as compared with the case where a dispersant is used.

Self-dispersing pigments (self-dispersing pigments) are surface-modified so that at least one hydrophilic group is bonded to the surface of the pigment directly or via another atomic group. In the surface modification, a specific functional group (a functional group such as a sulfone group or a carboxyl group) is chemically bonded to the surface of the pigment, or at least one of hypohalous acid and a salt thereof is used. A method such as wet oxidation is used. Among these, a form in which a carboxyl group is bonded to the surface of the pigment and dispersed in water is particularly preferable. As described above, the self-dispersing pigment is surface-modified and has a carboxyl group bonded thereto, so that not only the dispersion stability is improved, but also high-quality printing quality is obtained and a recording medium after printing (for recording) The water resistance of the media is further improved. In addition, since this form of ink has excellent redispersibility after drying, printing is paused for a long period of time, and clogging does not occur even when the ink moisture near the nozzles of the inkjet head evaporates, making it easy with a simple cleaning operation. Can print well.
The volume average particle diameter (D50) of the self-dispersing pigment is preferably 0.01 to 0.16 μm in the ink.

For example, as the self-dispersing carbon black, those having ionicity are preferable, and those having an anionic charge or those charged in a cationic form are suitable.
Examples of the anionic hydrophilic group include -COOM, -SO3M, -PO3HM, -PO3M2, -SO2NH2, and -SO2NHCOR (where M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium. R represents carbon. An alkyl group having 1 to 12 atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent). Among these, it is preferable to use those in which —COOM and —SO3M are bonded to the surface of the color pigment.
Moreover, as what "M" in the said hydrophilic group is an alkali metal, lithium, sodium, potassium, etc. are mentioned, for example. Examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium.
As a method of obtaining the anionically charged color pigment, as a method of introducing —COONa to the color pigment surface, for example, a method of oxidizing the color pigment with sodium hypochlorite, a method of sulfonation, a diazonium salt The method of making it react is mentioned.

  As the cationic hydrophilic group, for example, a quaternary ammonium group is preferable, and in the present invention, those in which these are bonded to the surface of carbon black are suitable as a coloring material.

There is no restriction | limiting in particular as a pigment which can be used for yellow ink as the thing for said colors, According to the objective, it can select suitably, for example, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 180, and the like.

  The pigment that can be used in the magenta ink is not particularly limited and may be appropriately selected depending on the intended purpose. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, pigment violet 19, and the like.

The pigment that can be used in the cyan ink is not particularly limited and may be appropriately selected depending on the purpose. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Bat Blue 60 and the like.
In addition, the pigment contained in each ink used in the present invention may be newly produced for the present invention.

By using Pigment Yellow 74 as the yellow pigment, Pigment Red 122 and Pigment Bio Red 19 as the magenta pigment, and Pigment Blue 15 as the cyan pigment, it is possible to obtain a well-balanced ink having excellent color tone and light resistance.
The content of the pigment in the ink is preferably 0.1% by mass or more and 50.0% by mass or less, and more preferably 0.1% by mass or more and 20.0% by mass or less.

The average particle diameter (D50) of the pigment is preferably 150 nm or less, and more preferably 100 nm or less. When the average particle diameter (D50) exceeds 150 nm, the ejection stability rapidly decreases, and nozzle clogging and ink bending are likely to occur. Further, if the average particle diameter (D50) is 100 nm or less, the ejection stability is improved and the saturation of the image is further improved.
This is because by reducing the amount of coarse particles of the pigment in the ink adhering to the nozzle plate, it is possible to prevent the ink repellent layer from being damaged due to the friction of the coarse particles in the ink during wiping. Further, it is possible to prevent irregular reflection of the pigment particles in the print image portion and provide a print image having a uniform density.
In addition, the volume average particle diameter (D50) of the pigment in the present invention is measured by a dynamic light scattering method using a particle size distribution measuring device (Nikkiso Co., Ltd., Nanotrac UPA-EX150).

  The color pigment is used as an aqueous pigment dispersion after being dispersed in water with the compound represented by the general formula (1). The aqueous pigment dispersion can be produced, for example, by the following method. First, the ratio of pigment to dispersant is determined. While dispersing a mixture of pigment and water with a known disperser such as a sand mill, roll mill, bead mill, nanomizer, homogenizer, etc., the dispersant was gradually added, and the viscosity became the smallest as the particle size decreased. Decide on the ratio. In addition, when dispersing by a bead mill, it is preferable to add a small amount of an antifoaming agent in order to suppress the generation of bubbles. The average particle diameter of the pigment can be controlled by the size of the beads to be added to the disperser, the dispersion time, etc. To make the average particle diameter 150 nm or less, the beads are 0.05 to 1.0 mm and the dispersion time is May be dispersed at 1 to 100 hours / L.

  The content of the pigment dispersant is preferably 1 to 100 parts by weight and more preferably 10 to 50 parts by weight with respect to 100 parts by weight of the pigment. If the content of the pigment dispersant is small, the pigment cannot be sufficiently miniaturized. If the content is too large, excess components that are not adsorbed on the pigment affect the ink physical properties, causing image bleeding, water resistance, resistance to water. It will cause deterioration of rubbing property.

The pigment dispersion uniformly finely dispersed in water by the pigment dispersant is dissolved in the above-mentioned pigment dispersant in an aqueous medium, and then sufficiently wetted by adding the above-mentioned pigment, followed by high-speed stirring by a homogenizer. It can be produced by a method using a dispersing machine using a ball such as a bead mill or a ball mill, a kneading dispersing machine using a shearing force such as a roll mill, an ultrasonic dispersing machine, or the like.
However, after such a kneading and dispersing step, coarse particles are often contained, which may cause clogging of the ink jet nozzle and the supply path. Therefore, particles having a particle diameter of 1 μm or more using a filter or a centrifuge. Need to be removed.

<Surfactant>
As the surfactant, those having a low surface tension, low penetrability, and high leveling properties are preferable without any loss of dispersion stability depending on the combination of pigment type and water-soluble organic solvent. Anionic surfactants, nonionic surfactants At least one selected from an agent, a silicone-based surfactant, and a fluorine-based surfactant is preferable. Among these, a fluorine-based surfactant is particularly preferable.
These surfactants can be used alone or in combination of two or more.

  As the fluorine-based surfactant, those having 2 to 16 carbon atoms substituted with fluorine are preferable, and those having 4 to 16 carbon atoms substituted with fluorine are more preferable. When the fluorine-substituted carbon number is less than 2, the effect of fluorine may not be obtained, and when it exceeds 16, a problem may occur in ink storage stability.

Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in a side chain. And polyoxyalkylene ether polymer compound. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is particularly preferable because of its low foaming property.
More preferably, it is a fluorine-type surfactant represented by the following general formula (2).

（ただし、前記一般式（２）中、ｍは０〜１０の整数を表す。ｎは１〜４０の整数を表す。）

(However, in said general formula (2), m represents the integer of 0-10. N represents the integer of 1-40.)

Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like.
Examples of the perfluoroalkyl carboxylic acid compound include perfluoroalkyl carboxylic acid and perfluoroalkyl carboxylate.
Examples of the perfluoroalkyl phosphate compound include perfluoroalkyl phosphate esters, perfluoroalkyl phosphate salts, and the like.
The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, and a polyoxyalkylene ether having a perfluoroalkyl ether group in the side chain. Examples thereof include a sulfate salt of a polymer and a salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain.

Counter ions of salts in these fluorinated _{surfactants, Li, Na, K, NH4} , NH 3 CH 2 CH 2 OH, NH 2 (CH 2 CH 2 OH) 2, NH (CH 2 CH 2 OH) 3 , Etc.

As said fluorosurfactant, what was synthesize | combined suitably may be used and a commercial item may be used.
Examples of the commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F -1405, F-474 (all manufactured by Dainippon Ink & Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all of which are Neo Co., Ltd.) And manufactured by Polyfox PF-151N (Omnova).

<Penetration agent>
The recording ink of the present invention preferably contains at least one polyol compound or glycol ether compound having 8 to 11 carbon atoms as a penetrant. These preferably have a solubility of between 0.2 and 5.0% by weight in water at 25 ° C. Among these, 2-ethyl-1,3-hexanediol [solubility: 4.2% (25 ° C.)], 2,2,4-trimethyl-1,3-pentanediol [solubility: 2.0% (25 ° C)] is particularly preferred.

  Examples of the aliphatic diol exemplified as the other polyol compound include 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, and 2,2-diethyl-1. , 3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene -1,2-diol and the like.

  Other penetrants that can be used in combination are not particularly limited as long as they can be dissolved in ink and adjusted to desired physical properties, and can be appropriately selected according to the purpose. Examples of penetrants that can be used in combination include, for example, polyvalent polyethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl ether, and the like. Examples thereof include alkyl and aryl ethers of alcohol, lower alcohols such as ethanol, and the like.

  The content of the penetrant in the ink jet recording ink (substantially, recording ink) of the present invention is preferably 0.1 to 4.0% by mass. When the content is less than 0.1% by mass, quick-drying may not be obtained and a blurred image may be obtained. When the content exceeds 4.0% by mass, the dispersion stability of the colorant is impaired, and the nozzle In some cases, clogging is likely to occur, and the permeability to the recording medium is unnecessarily high, resulting in a decrease in image density and through-through.

<Water dispersible resin>
Water-dispersible resins are excellent in film-forming properties (image forming properties) and have high water repellency, high water resistance, and high weather resistance, and are useful for recording images with high water resistance and high image density (high color development). It is.
Examples of the water-dispersible resin include condensation-type synthetic resins, addition-type synthetic resins, and natural polymer materials.
Examples of the condensed synthetic resin include polyester resins, polyurethane resins, polyepoxy resins, polyamide resins, polyether resins, poly (meth) acrylic resins, acrylic silicone resins, and fluorine resins.
Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like.
Examples of the natural polymer material include celluloses, rosins, and natural rubber.

  Among these, when polyurethane resin fine particles are used, when ink lands on a recording medium such as paper, it has the property of thickening or agglomerating, suppressing the penetration of colored components, and further promoting fixing on paper. Has the effect of In addition, compared with other resins, it has a strong effect of forming a film on paper and improving the abrasion resistance of the printed matter.

There is no problem in using two or more water-dispersible resins in combination.
The water-dispersible resin may be used as a homopolymer, may be used as a copolymer and may be used as a composite resin, and any of a single-phase structure type, a core-shell type, and a power feed type emulsion may be used. it can. As the water-dispersible resin, a resin itself having a hydrophilic group and having a self-dispersibility, or a resin itself having no dispersibility and imparted with a surfactant or a resin having a hydrophilic group can be used. .

  As a method for synthesizing a polyurethane resin, an isocyanate-terminated prepolymer is synthesized in a low-boiling solvent (acetone, etc.) that does not react with an isocyanate group, a hydrophilic group is introduced with a diamine, a polyol, etc., and then diluted with water and phase-converted. , A solution method to obtain a polyurethane dispersion by distilling off the solvent, a prepolymer method in which an isocyanate group-terminated prepolymer having a hydrophilic group introduced therein is first synthesized, dispersed in water, and then chain-extended with an amine, etc. Melt method, Method using polyurethane prepolymer and water as a medium in emulsifier aqueous solution, Sulfonating aromatic ring of polyurethane prepolymer having free isocyanate group obtained from hydrophobic polyol and aromatic polyisocyanate Using a blocked isocyanate How to such, it is known in various ways, but is not particularly limited.

  When a polyurethane resin is synthesized by the prepolymer method, a low molecular weight polyhydroxy compound may be used. Examples of such polyhydroxy compounds include glycol and alkylene oxide low molar adducts mentioned as raw materials for polyester diols, trihydric alcohols such as glycerin, trimethylol ethane, and trimethylol propane, and alkylene oxide low molar adducts. Can be mentioned.

In the case of an aqueous polyurethane resin, a method is generally known in which a polyurethane 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 the chain extender. Specifically, the polyurethane prepolymer is water-extended or di- or triamine-extended 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 polyurethane resin using polyamines is used as the chain extender, the storage stability of the recording liquid tends to be poor. This is because the amine-extended polyurethane resin (polyurethane resin containing a polyurethane urea portion) is prone to hydrolysis, and furthermore, polyamines generated by hydrolysis also act as an aggregating agent in the carbon black dispersion recording liquid. It is speculated that it has a double adverse effect.

The polyurethane resin can be used in the form of an alkali metal salt such as Li, Na and K, an organic amine salt such as ammonia, dimethylamine, and (mono, di, tri) ethanolamine.
These can be obtained by further neutralizing the polyurethane 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.
The content of the polyurethane resin in the ink for inkjet recording is preferably 0.1 to 20% by weight, more preferably 0.2 to 10% by weight as the resin solid content. After landing on the recording medium, the addition amount that is quantitatively sufficient for the resin to cover the carbon black is preferably 0.1% by mass or more, in order to maintain the viscosity necessary for maintaining the ejection characteristics of the ink jet system. The amount added is preferably 20% by mass or less.

Here, the solid content of the colorant, the pigment in the colorant, and the water-dispersible resin can be measured by, for example, a method of separating only the colorant and the water-dispersible resin from the ink. it can. Further, when a pigment is used as the colorant, the ratio of the colorant to the water-dispersible resin can be measured by evaluating the mass reduction rate by thermal mass spectrometry. In addition, when the molecular structure of the colorant is clear, it is possible to quantify the solid content of the colorant using NMR for pigments and dyes, including heavy metal atoms, inorganic pigments contained in the molecular skeleton, For organic pigments and metal-containing dyes, the solid content of the colorant can be quantified by using fluorescent X-ray analysis.
The ink-jet ink of the present invention is not limited, but since the water content is usually more than 50% by mass and the total amount of resin and pigment is usually more than 3% by mass, the solvent evaporation rate is usually 50%. It becomes mass%-97 mass%.

<Other ingredients>
As described above, the other components are not particularly limited and may be appropriately selected as necessary. For example, a pH adjuster, an antiseptic / antifungal agent, a chelating reagent, an antirust agent, an antioxidant, An ultraviolet absorber, an oxygen absorber, a light stabilizer, etc. are mentioned.

  The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 to 11 without adversely affecting the recording ink to be prepared, and can be appropriately selected according to the purpose. Examples include alcohol amines, alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like. If the pH is less than 7 or more than 11, the amount of the ink jet head or ink supply unit that melts out is large, and problems such as ink deterioration, leakage, and ejection failure may occur.

Examples of the alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.
Examples of the ammonium hydroxide include ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, and the like.
Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

  Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, sodium pentachlorophenol, and the like.

  Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  Examples of the antioxidant include phenolic antioxidants (including hindered phenolic antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.

  Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex ultraviolet absorber.

  Examples of the benzophenone-based ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. 2,2 ′, 4,4′-tetrahydroxybenzophenone, and the like.

  Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, and the like.

  Examples of the salicylate-based ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, and the like.

  Examples of the cyanoacrylate-based ultraviolet absorber include ethyl-2-cyano-3,3′-diphenyl acrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate, and butyl-2- And cyano-3-methyl-3- (p-methoxyphenyl) acrylate.

  Examples of the nickel complex-based ultraviolet absorber include nickel bis (octylphenyl) sulfide, 2,2′-thiobis (4-tert-octylferrate) -n-butylamine nickel (II), and 2,2′-thiobis. (4-tert-octyl ferrate) -2-ethylhexylamine nickel (II), 2,2′-thiobis (4-tert-octyl ferrate) triethanolamine nickel (II), and the like.

(ink cartridge)
The ink cartridge of the present invention accommodates the ink for ink jet recording of the present invention in a container, and can also constitute other members appropriately selected as necessary.
The shape, structure, size, and material of the container are not particularly limited and can be appropriately selected according to the purpose. Preferred examples include those having at least an ink bag formed of an aluminum laminate film, a resin film, or the like.

  One embodiment of the ink cartridge of the present invention will be described with reference to FIGS. FIG. 1 is a schematic plan view for explaining an example of the ink cartridge of the present invention. FIG. 2 is a schematic plan view including a case (exterior) of the ink cartridge of FIG.

  As shown in FIG. 1, the ink cartridge 200 is filled into the ink bag 241 from the ink inlet 242 and exhausted, and then the ink inlet 242 is closed by fusion. In use, the needle of the apparatus main body is pierced 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. 2, the ink bag 241 is usually housed in a plastic cartridge case 244 and is detachably mounted on various ink jet recording apparatuses.

(Inkjet recording apparatus and inkjet recording method)
The ink jet recording apparatus of the present invention has at least ink ejecting means for recording the image on the recording medium by ejecting the ink for ink jet recording of the present invention from the recording head, and other means appropriately selected as necessary. , For example, comprising stimulus generating means, control means and the like.

The ink jet recording method using the ink of the present invention includes at least an ink flying process, and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.
The ink jet recording method using the ink of the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.
The method for producing an ink jet recorded matter of the present invention comprises an ink flying step of recording an image on a recording medium by applying a stimulus to the ink for ink jet recording of the present invention via an ink flying means and causing the ink to fly from the recording head. Including at least.

The ink flying step is a step of forming an image by applying a stimulus to the ink jet ink of the present invention and causing the ink jet ink to fly.
The ink flying means is means for forming an image by applying a stimulus to the ink-jet ink of the present invention and causing the ink-jet ink to fly. The ink flying means is not particularly limited, and examples thereof include various nozzles for ejecting ink.

  The stimulus can be generated, for example, by the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, such as heat (temperature), pressure, vibration, light, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferable. Examples of the stimulus generating means include a superheater, a pressurizer, a piezoelectric element, a vibration generator, an ultrasonic oscillator, and a light. Specifically, a piezoelectric actuator such as a piezoelectric element such as a piezoelectric element, a thermal actuator that uses a phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a shape that uses a metal phase change due to a temperature change Memory alloy actuators, electrostatic actuators using electrostatic force, and the like can be mentioned.

  There is no particular limitation on the mode of the ink flying, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, the thermal energy corresponding to the recording signal is output to the ink in the recording head. For example, using a thermal head or the like, generating bubbles in the ink by the thermal energy, and ejecting and ejecting the ink as droplets from the nozzle holes of the recording head by the pressure of the bubbles. It is done. Further, when the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. And a method of ejecting and ejecting the ink as droplets from the nozzle holes of the recording head.

  The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

Here, one aspect of carrying out the ink jet recording method of the present invention by the ink jet recording apparatus of the present invention will be described with reference to the drawings.
FIG. 3 is a perspective view showing an example of the ink jet recording apparatus of the present invention.
The ink jet recording apparatus shown in FIG. 3 stocks an apparatus main body 101, a paper feed tray 102 for loading paper loaded on the apparatus main body 101, and paper on which an image is recorded (formed) mounted on the apparatus main body 101. A paper discharge tray 103 and an ink cartridge loading unit 104 protruding forward from the front surface 112 and lower than the upper cover 111 are provided at one end of the front surface 112 of the apparatus main body 101. On the upper surface of the ink cartridge loading unit 104, an operation unit 105 such as operation keys and a display is arranged. The ink cartridge loading unit 104 has a front cover 115 that can be opened and closed for attaching and detaching the ink cartridge 200.

  As shown in FIGS. 4 and 5 (partially enlarged sectional view of the ink jet recording apparatus shown in FIG. 3), a guide which is a guide member horizontally mounted on left and right side plates (not shown) is provided in the apparatus main body 101. The carriage 133 is slidably held in the main scanning direction by the rod 131 and the stay 132, and is moved and scanned in the direction of the arrow as shown in FIG. 5 by the main scanning motor.

The carriage 133 is provided with a recording head 134 composed of four ink jet recording heads that eject 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 the ink jet recording head constituting the recording head 134, a piezoelectric actuator such as a piezoelectric element, a thermal actuator using phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a metal phase due to temperature change, etc. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging ink can be used. In addition, 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 the ink from the ink cartridge 200 of the present invention loaded in the ink cartridge loading unit 104 via an ink supply tube (not shown) and is 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 feeding tray 102, a half-moon roller (feeding) that separates and feeds the paper 142 from the paper stacking unit 141 one by one. A separation pad 144 made of a material having a large coefficient of friction is provided facing the paper roller 143) and the paper feed roller 143, and the separation pad 144 is urged toward the paper feed roller 143 side.
As a transport unit for transporting the paper 142 fed from the paper feed unit below the recording head 134, a transport belt 151 for transporting the paper 142 by electrostatic adsorption and a guide 145 from the paper feed unit. The counter roller 152 for transporting the paper 142 fed via the transport belt 151 with the transport belt 151 and the paper 142 fed substantially vertically upward are changed by approximately 90 ° to follow the transport belt 151. For this purpose, a conveyance guide 153 and a tip pressure roller 155 urged toward the conveyance belt 151 by a pressing member 154 are provided.

In addition, a charging roller 156 that is a charging unit for charging the surface of the conveyance belt 151 is provided. 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 that is not subjected to resistance control, for example, a copolymer of tetrafluoroethylene and ethylene (ETFE), and the surface layer. It has a back layer (medium resistance layer, earth layer) that is made of the same material and has resistance controlled by carbon. On the back side of the conveyance belt 151, a guide member 161 is arranged corresponding to a printing area by the recording head 134.
Note that, 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 conveyance belt 151, a paper discharge roller 172, and a paper discharge roller 173 are provided. The paper discharge tray 103 is disposed below the paper discharge roller 172.

A double-sided paper feeding unit 181 is detachably mounted on 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 it again between the counter roller 152 and the transport belt 151. A manual paper feed unit 182 is provided on the upper surface of the duplex paper feed unit 181.

  In this ink jet recording apparatus, the paper 142 is separated and fed one by one from the paper feed unit, and the paper 142 fed substantially vertically upward is guided by the guide 145 and between the transport belt 151 and the counter roller 152. It is sandwiched and conveyed. 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 approximately 90 °. At this time, the conveying belt 151 is charged by the charging roller 156, and the sheet 142 is electrostatically attracted to the conveying 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 paper 142 to record one line, and after the paper 142 is conveyed by a predetermined amount, Record the next line.

  Upon receiving a recording end signal or a signal that the trailing edge of the sheet 142 has reached the recording area, the recording operation is terminated and the sheet 142 is discharged onto the discharge tray 103. When the ink remaining amount near end 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 201 of the present invention 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 installed vertically and has a front loading configuration. Therefore, the ink cartridge 200 is installed even when the upper portion of the apparatus main body 101 is closed, for example, when stored in a rack, or when an object is placed on the upper surface of the apparatus main body 101. Can be easily exchanged.
In addition, although it demonstrated in the example applied to the serial type (shuttle type) inkjet recording device which a carriage scans, it can apply similarly to the line type inkjet recording device provided with the line type head.

  The ink jet recording apparatus of the present invention can be applied to various types of recording by the ink jet recording method, and is particularly preferably applied to, for example, an ink jet recording printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like. Can do.

<Waste ink path>
FIG. 6 shows an outline of a waste ink feeding path from the head to the waste ink tank.
The ink ejected from the head 1 or scraped off by the cleaning blade 2 reaches the waste ink box 5 from the waste ink receiver 3 through the liquid feed pipe 4 and is absorbed by the ink absorber 6.
It is preferable to use a material having a high ink holding capacity for the ink absorber 6. Examples of the material of the ink absorber include a laminated sheet of paper, an absorber including a polymer absorber, a high density fiber structure polyurethane such as felt, a foam forming material such as cellulose, PVA, EVA, or acrylic. High water absorbency such as acid graft starch, acrylic salt graft starch, vinyl alcohol acrylic acid block copolymer, vinyl alcohol acrylic salt block copolymer, cross-linked polyacrylic acid, cross-linked polyacrylic salt, modified PVA, polystyrene sulfonic acid, cellulose ether, carboxymethyl cellulose Examples include the water-absorbing material described above containing a molecular polymer. Further, the waste ink absorber made of these materials is made by, for example, a punching die.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

[Ink Production Example 1; Preparation of Ink 1]
(Preparation of pigment dispersion 1)
・ C. I. Pigment Blue 15: 3 ... 15 parts by weight (Dainippon Seika Co., Ltd., Cyanine Blue A-292)
・ Polyoxyethylene β-naphthyl ether represented by the following general formula (1)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 12 parts by weight ・ Ion-exchanged water ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 73 parts by weight

（ただし、前記一般式（１）中、Ｌ＝０、ｎは４０を表す。）

(However, in said general formula (1), L = 0 and n represents 40.)

After premixing the above mixture, the mixture was circulated and dispersed in a disk-type bead mill (Shinmaru Enterprises KDL type, media: use of zirconia balls having a diameter of 0.3 mm) to obtain pigment dispersion 1.

(Preparation of ink 1)
・ Pigment dispersion 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・········ 10 parts by weight · Diethylene glycol ··························································· Agent ... 2 parts by weight-Urethane resin emulsion W5661; made by Mitsui Takeda Chemical Co., Ltd.-2 parts by weight-Ion-exchanged water ... .... 20.7 parts by weight

（ただし、前記一般式（２）中、ｍは２、ｎは１０を表す。）

(However, in said general formula (2), m represents 2 and n represents 10.)

An ink was prepared according to the above formulation, stirred for 1 hour and 30 minutes, and then filtered through a membrane filter having a pore size of 0.8 μm to obtain an ink.
The order of ink preparation was (1) glycerin and diethylene glycol, (2) surfactant, (3) ion-exchanged water, stirred for 30 minutes, then added the pigment dispersion (a) and stirred for 1 hour. Ink 1 was prepared.

[Ink Production Example 2; Preparation of Ink 2]
(Preparation of pigment dispersion 2)
・ C. I. Pigment Red 122 ... 15 parts by weight (Da Nippon Ink Chemical Co., Ltd., FASTOGEN SUPER MAGENTA RG)
・ Polyoxyethylene β-naphthyl ether represented by the above general formula (1))
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 10 parts by weight ・ Ion-exchanged water ... 75 parts by weight After premixing, the mixture was circulated and dispersed with a disk-type bead mill (Shinmaru Enterprises KDL type, media: zirconia balls having a diameter of 0.3 mm) to obtain a pigment dispersion (b).

(Preparation of ink 2)
・ Pigment dispersion 2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・········ 10 parts by weight · Diethylene glycol ···········································・ 2 parts by weight ・ Urethane resin emulsion W5661; made by Mitsui Takeda Chemical Co., Ltd. ・ 2 parts by weight ・ Ion exchange water ・ ・ ・ ・ ・ ・20.7 parts by weight Ink was prepared according to the above formulation, stirred for 1 hour 30 minutes, and then filtered through a membrane filter with a pore size of 0.8 μm to obtain ink. It was.
The ink was prepared in the order of (1) glycerin and diethylene glycol, (2) surfactant, (3) ion-exchanged water, stirred for 30 minutes, then added with the pigment dispersion 2 and stirred for 1 hour to prepare ink 2 Was prepared.

[Ink Production Example 3; Preparation of Ink 3]
<Example of preparation of pigment dispersion 3>
(Preparation of pigment dispersion 3)
・ C. I. Pigment Yellow 74 ... 15 parts by weight (Dainippon Seika Co., Ltd., Yellow No. 43)
・ Polyoxyethylene-β-naphthyl ether of the above general formula (1) ・ ・ 10 parts by weight ・ Ion exchange water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ 75 parts by weight After premixing the above mixture, the pigment dispersion liquid (c) was dispersed by circulation with a disk-type bead mill (Shinmaru Enterprises KDL type, media: using zirconia balls having a diameter of 0.3 mm). Obtained.

(Preparation of ink 3)
・ Pigment dispersion 3 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・········ 10 parts by weight · Diethylene glycol ···········································・ 2 parts by weight ・ Urethane resin emulsion W5661; made by Mitsui Takeda Chemical Co., Ltd. ・ 2 parts by weight ・ Ion exchange water ・ ・ ・ ・ ・ ・20.7 parts by weight Ink was prepared according to the above formulation, stirred for 1 hour 30 minutes, and then filtered through a membrane filter with a pore size of 0.8 μm to obtain ink. It was.
The ink was prepared in the order of (1) glycerin and diethylene glycol, (2) surfactant, (3) ion-exchanged water, stirred for 30 minutes, added with the pigment dispersion 3 and stirred for 1 hour to prepare ink 3 Was prepared.

[Ink Production Example 4; Preparation of Ink 4]
(Preparation of pigment dispersion 4)
・ Carbon black # 40 (Mitsubishi Chemical Co., Ltd.) ・ ・ ・ ・ ・ ・ 15 parts by weight ・ Polyoxyethylene-β-naphthyl ether of general formula (1) above ・ 10 parts by weight ・ Ion Exchanged water: 75 parts by weight After premixing the above mixture, a disk-type bead mill (Shinmaru Enterprises Co., Ltd.) A pigment dispersion 4 was obtained by circulation and dispersion using a KDL type, media: zirconia balls having a diameter of 0.3 mm.

(Preparation of ink 4)
・ Pigment dispersion 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... 10 parts by weight-Diethylene glycol ... 25.3 parts by weight-General formula (2) above 2 parts by weight ・ Urethane resin emulsion W5661; made by Mitsui Takeda Chemicals ・ ・ ・ ・ 2 parts by weight ・ Ion-exchanged water 20.7 parts by weight An ink was prepared according to the above formulation, stirred for 1 hour and 30 minutes, and then filtered through a membrane filter having a pore size of 0.8 μm to obtain an ink.
The ink was prepared in the order of (1) glycerin and diethylene glycol, (2) surfactant, (3) ion-exchanged water, stirred for 30 minutes, then added with the pigment dispersion 4 and stirred for 1 hour for ink 4 Was prepared.

[Ink Production Example 5; Preparation of Ink 5]
(Preparation of pigment dispersion 5 (surface-treated black pigment dispersion))
90 g of carbon black having a CTAB specific surface area of 150 m2 / g and DBP oil absorption of 100 ml / 100 g is added to 3,000 ml of 2.5 N sodium sulfate solution, stirred at a temperature of 60 ° C. and a speed of 300 rpm, and allowed to react for 10 hours. Oxidation treatment was performed. The reaction solution was filtered, and the carbon black separated by filtration was neutralized with a sodium hydroxide solution and subjected to ultrafiltration. The obtained carbon black was washed with water, dried, dispersed in ion-exchanged water so as to have a solid content of 30% by mass, and sufficiently stirred to obtain a black pigment dispersion 5. The average particle diameter (D50) of the pigment dispersion in this black pigment dispersion was measured and found to be 103 nm.

(Preparation of ink 5)
・ Pigment dispersion 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・········ 10 parts by weight · Diethylene glycol ··············································· Represented by the general formula (2) Surfactant: 2 parts by weight Urethane resin emulsion W5661; made by Mitsui Takeda Chemical Co., Ltd .: 2 parts by weight Ion exchange water 20.7 parts by weight Ink was prepared according to the above formulation, stirred for 1 hour 30 minutes, filtered through a membrane filter with a pore size of 0.8 μm, and the ink was removed. Obtained.
The ink was prepared in the order of (1) glycerin and diethylene glycol, (2) surfactant, (3) ion-exchanged water, stirred for 30 minutes, added with the pigment dispersion 5 and stirred for 1 hour to prepare ink 5 Was made.

[Ink Production Example 6; Preparation of Ink 6]
(Preparation of ink 6)
In Preparation of Ink 1>
・ Pigment dispersion 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・······ 8.0 parts by weight · Diethylene glycol ········································· Represented by general formula (2) Surfactant ········ 2 parts by weight · Urethane resin emulsion W5661; made by Mitsui Takeda Chemicals · · · 2 parts by weight · ion-exchanged water ··· Ink was prepared in the same manner as in ink 1 except that the amount was 20 parts by weight, and ink 6 was obtained.

[Ink Comparative Production Example 1; Preparation of Ink R1]
(Preparation of comparative ink R1)
In the preparation of ink 1,
・ Pigment dispersion 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ 25.0 parts by weight ・ Diethylene glycol ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 10 parts by weight ・ Represented by the above general formula (2)・ 2 parts by weight ・ Urethane resin emulsion W5661; made by Mitsui Takeda Chemical Co., Ltd. ・ 2 parts by weight ・ Ion exchange water ・ ・ ・ ・ ・ ・Ink R1 was obtained in the same manner as the ink 1 except that the amount was 21 parts by weight.

[Ink Comparative Production Example 2; Preparation of Ink R2]
(Preparation of comparative ink R2)
In the preparation of ink R1,
・ Pigment dispersion 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ 25.0 parts by weight ・ Diethylene glycol ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 8.6 parts by weight ・ Represented by the above general formula (2) Surfactant ... 2 parts by weight Urethane resin emulsion W5661; made by Mitsui Takeda Chemical Co., Ltd. ... 2 parts by weight ion-exchanged water ... Ink R2 was obtained by preparing an ink in the same manner as the ink 1 except that the amount was 22.4 parts by weight.

[Ink Comparative Production Example 3; Preparation of Ink R3]
・ Pigment dispersion 2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 5 parts by weight ・ Diethylene glycol… 30.3 parts by weight ・ Surfactant represented by the above general formula (2) ... 2 parts by weight-Urethane resin emulsion W 5661; manufactured by Mitsui Takeda Chemical Co., Ltd. ... 2 parts by weight-Ion exchange water ... 20.7 parts by weight An ink was prepared according to the above formulation, stirred for 1 hour and 30 minutes, and then filtered through a membrane filter having a pore size of 0.8 μm to obtain ink R3.
The ink was prepared in the order of (1) glycerin and diethylene glycol, (2) surfactant, (3) ion-exchanged water, stirred for 30 minutes, then added with the pigment dispersion 2 and stirred for 1 hour for ink R3. Was prepared.

[Ink Comparative Production Example 4; Preparation of Ink R4]
・ Pigment dispersion 2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40 parts by weight ・ Glycerin ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 15 parts by weight ・ Diethylene glycol ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 20.3 parts by weight ・ Represented by the above general formula (2)・ 2 parts by weight ・ Urethane resin emulsion W5661; made by Mitsui Takeda Chemical Co., Ltd. ・ 2 parts by weight ・ Ion exchange water ・ ・ ・ ・ ・ ・20.7 parts by weight Ink was prepared according to the above formulation, stirred for 1 hour and 30 minutes, filtered through a membrane filter with a pore size of 0.8 μm, and ink R4 was removed. Obtained.
The ink was prepared in the order of (1) glycerin and diethylene glycol, (2) surfactant, (3) ion-exchanged water, stirred for 30 minutes, then added with the pigment dispersion 2 and stirred for 1 hour for ink R4. Was prepared.
Table 1 shows the viscosity of each of the obtained inks.

[Example 1 to Example 3, Comparative Example R1 to Comparative Example R4; Ink Sets 1 to 3, R1 to R4]
The inks 1 to 6 and the inks R1 to R4 are selected and combined as shown in the following table, and ink sets 1 to 3 of Examples 1 to 3 and ink sets of Comparative Examples R1 to R4 are used. R1 to R4.

[Evaluation of ink ejection stability and evaluation of image density]
The ejection stability and image density of the prepared recording ink were evaluated under the following conditions. The results are shown in the table below.

[Measuring method]
<Casson yield value>
After drying in an environment of 50 ° C. and 10% RH for 48 hours, measurement is performed using a rheometer (MCR301 manufactured by Anton Paar) in an environment of 25 ° C. and 50% RH. At this time, a gap (Gap) is set to 50 μm using a flat plate having a diameter of 5 (cm). When the shear stress is measured for a shear rate of 1 to 1000 (1 / s), the square of the intercept b when the graph is extrapolated so that the square root √D of the shear rate becomes 0 in the following formula (1) is Casson. Yield value.

（Ｓ：せん断応力、Ｄ：せん断速度、（ａ、ｂは係数）
上記式（２）においてせん断速度の平方根√Ｄの２乗が０になるように直線グラフを外挿したときの切片ｂの２乗がＣａｓｓｏｎ降伏値となる。

(S: shear stress, D: shear rate, (a and b are coefficients)
In the above formula (2), the square of the intercept b when extrapolating the straight line graph so that the square of the square root √D of the shear rate becomes 0 becomes the Casson yield value.

<Viscosity>
Measurement is performed using a rheometer (MCR301 manufactured by Anton Paar) in an environment of 25 ° C. and 50% RH. At this time, a gap (Gap) is set to 50 μm using a flat plate having a diameter of 5 (cm). The viscosity at a shear rate of 100 (1 / s) was measured.

<Discharge stability>
Using an inkjet printer (IPSiO GXe5500, manufactured by Ricoh Co., Ltd.), the drive voltage of the piezo element was varied so that the amount of ink discharged was uniform, and a solid area of 5% of A4 size paper per color created with Microsoft Word 2000 was obtained. One chart to be filled with an image was punched out on My Paper (manufactured by NBS Ricoh Co., Ltd.), and it was confirmed that there was no discharge disturbance. Thereafter, the maintenance cap of the printer was separated from the nozzles to open the nozzles, and then left in an environment of 40 ° C. and 10% RH for 3 hours. Thereafter, the same chart as that in the initial stage was printed, and ejection disturbance of each nozzle was evaluated according to the following criteria. The printing mode used was a driver attached to the printer, in which the “plain paper-standard faster” mode was changed to “no color correction” than the user setting for plain paper.
〔Evaluation criteria〕
○: Discharge all nozzles Δ: Less than 10 nozzles that do not discharge ×: 10 or more nozzles that do not discharge

<Image density>
A chart with 64 point characters “■” created with Microsoft Word 2000 is printed on My Paper (manufactured by NBS Ricoh Co., Ltd.), and the “■” portion of the printed surface is measured with X-Rite 938. Judged. The printing mode used was a driver attached to the printer, in which the “plain paper-standard faster” mode was changed to “no color correction” than the user setting for plain paper.

<Waste ink absorbency>
Using an ink jet printer (IPSiO GXe5500, manufactured by Ricoh Co., Ltd.), image formation was continuously performed with the created ink set. Waste ink tank full detection was turned off, printing was performed until ink overflowed from the ink inlet of the waste ink tank, and the weight of the waste ink tank at the end was measured.

<Head cleaning performance>
Using an ink jet printer (IPSiO GXe5500, manufactured by Ricoh Co., Ltd.), image formation was intermittently performed with the created ink set. Image formation was performed at a rate of one sheet per minute, and after continuous image formation for 6 hours, the image was left for 18 hours for 7 days. The test was performed in an environment of 23 ° C. and 40% RH.
After the seventh time, the cleaning operation was performed once, and the head surface was visually observed.

〔Evaluation criteria〕
◯: No ink wiping left Δ: Ink wiping left on 50% or less of the head surface ×: Ink wiping left on 50% or more of the head surface These evaluation results are shown in the following table.

As is apparent from the results, the amount of ink retained in the waste ink tank was increased by the ink set of the present invention.
At the same time, the discharge stability was also improved.

101 apparatus main body 102 paper feed tray 103 paper discharge tray 104 ink cartridge loading unit 105 operation unit 111 upper cover 112 front surface 115 front cover 131 guide rod 132 stay 133 carriage 134 recording head 135 sub tank 141 paper placement unit 142 paper 143 paper supply roller 144 Separator Pad 145 Guide 151 Conveyor Belt 152 Counter Roller 153 Conveyor Guide 154 Pressing Member 155 Tip Pressure Roller 156 Charging Roller 157 Conveying Roller 158 Densation Roller 161 Guide Member 171 Separation Claw 172 Discharge Roller 173 Discharge Roller 181 Unit 182 Manual paper feed unit 200 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge case

JP 2000-141705 A JP 2008-62430 A JP 2000-198956 A JP 2014-37495 A

Claims (5)

Black ink containing at least water, wetting agent, pigment, and polyurethane resin, and color ink containing at least water, polyoxyethylene-β-naphthyl ether of the following general formula (1), wetting agent, pigment, and polyurethane resin The black ink and the color ink have a viscosity at 25 ° C. of 4 mPa · s or more and 6 mPa · s or less,
An ink set characterized by a Casson yield value of 0.3 Pa or less.

(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 7, and n represents an integer of 20 to 200.)
2. The ink set according to claim 1, wherein the pigment contained in the black ink contains a dispersed pigment dispersed by the compound of the general formula (1).
The ink set according to claim 1, wherein the pigment contained in the black ink includes a self-dispersing pigment.
An ink cartridge comprising the ink set according to any one of claims 1 to 3 accommodated in a container.
  4. Inkjet recording having ink flying means for applying a stimulus to each ink of the ink set according to any one of claims 1 to 3 and causing the ink to fly as droplets from a recording head to record an image on a recording medium. apparatus.

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