JP2018161854A - Image formation device and image formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device capable of providing images excellent in blocking resistance and scratch resistance even when pressure is applied to the images, and high in glossiness.SOLUTION: An image formation device 1 has a first ink adding means 4 for forming images by adding a first ink to a recording medium 2 and a compression means 5 for applying pressure to the images, in which the first ink contains water, an organic solvent and a coper phthalocyanine pigment, the first ink has a characteristic that it takes a maximum value at logarithmic decrement of 7200 sec. or less when an ink film formed by the first ink is measured under a condition of 60°C by a rigid body pendulum test and the maximum value is 0.300 or less, and the pressure is 3.5 kg/cmto 16.0 kg/cm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus and an image forming method.

  The ink jet recording method not only has the advantage that the noise of the apparatus to be used is small and the operability is good, but also has the advantage that it can be easily colored and can use plain paper as a recording medium. Widely used as an output machine in offices and homes.

  On the other hand, in industrial applications, use as an output machine for digital printing is expected due to improvements in inkjet technology, and printing machines capable of recording on non-absorbing recording media using solvent ink and UV ink have been marketed. It was. However, in recent years, demand for water-based inks has increased due to environmental concerns.

  Ink-jet water-based inks have been developed for a long time as special printing papers such as plain paper and photographic glossy paper. On the other hand, in recent years, the application of the ink jet recording system is expected to be expanded, and the need for printing on coated paper such as coated paper is increasing. However, it is difficult to firmly fix the pigment on a recording medium having low permeability such as coated paper.

  In industrial applications, a roll paper type printer using roll paper as a printing medium has been developed. For example, the displacement amount of the movable member is controlled with good responsiveness to effectively prevent the movable member from moving beyond the movable range, and the movable member is damaged, vibrated or abnormally affected by colliding with the inner surface of the equipment casing. There has been proposed a roll paper transport device that can avoid problems such as occurrence of paper and paper stains (see Patent Document 1).

  An object of the present invention is to provide an image forming apparatus that is excellent in blocking resistance and rubbing resistance and that can provide an image having high gloss.

An image forming apparatus of the present invention that solves the above-described problems includes a first ink applying unit that forms an image by applying a first ink to a recording medium, and a pressurizing unit that applies pressure to the image. The first ink contains water, an organic solvent, and a copper phthalocyanine pigment, and the first ink is obtained by subjecting an ink film formed using the first ink to a condition of 60 ° C. by a rigid pendulum test. The logarithmic decay rate when measured with a maximum value is 7200 seconds or less and the maximum value is 0.300 or less, and the pressure is 3.5 kg / cm ² or more and 16.0 kg / cm. ² or less.

  According to the present invention, it is possible to provide an image forming apparatus that is excellent in blocking resistance and rubbing resistance and from which an image having high gloss can be obtained.

FIG. 1 is a schematic diagram showing an example of an image forming apparatus of the present invention. FIG. 2 is an example of a graph showing the relationship between the logarithmic decay rate and the elapsed time.

<Image Forming Apparatus and Image Forming Method>
Embodiments of the present invention will be described below.
An image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.
An image forming apparatus 1 illustrated in FIG. 1 is an apparatus that forms an image on a recording medium 2 by applying ink to the recording medium 2. The image forming apparatus 1 includes a paper feeding unit 3, an ink applying unit (first ink applying unit) 4, and a winding unit 5.

  The paper feeding unit 3 is a unit that feeds the recording medium 2 to a position where the ink applying unit 4 applies ink.

  The ink applying unit 4 is a unit that forms an image by applying ink to the fed recording medium 2. As the ink applying means 4, means for applying by an ink jet recording method is preferable. In the case of means for applying by the ink jet recording method, it is preferable to have four ejection heads corresponding to black (K), cyan (C), magenta (M), and yellow (Y). In addition to the ink jet recording method, ink is applied using, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, or a spray coating method. The means to do is mentioned. The ink application process as one process of the image forming method can be preferably performed by an ink application unit. Details of the ink will be described later.

  The winding unit 5 is disposed at a position facing the sheet feeding unit 3 and is a unit that winds the recording medium 2 fed from the sheet feeding unit 3. In the example shown in FIG. 1, continuous paper is used as the recording medium 2. Continuous paper is a recording medium that is continuous in the transport direction during image formation and is longer than the length of a print unit (one page) in the transport direction. As continuous paper, for example, roll paper rolled into a roll can be used. In the example shown in FIG. 1, a recording medium 2 rolled into a roll shape is set in the paper feeding means 3. Then, the recording medium 2 fed from the paper feeding means 3 is taken up by using the winding means 5 so that the recording medium 2 is carried in the carrying direction (the direction indicated by the arrow in FIG. 1).

  In the image forming apparatus shown in FIG. 1, the winding unit 5 also functions as a pressurizing unit that applies pressure to the image formed on the recording medium 2. That is, the winding means 5 winds the recording medium 2 after the image is formed in a roll shape, and pressure is applied to the recording medium 2 in the process of winding the recording medium 2 in the roll shape. In particular, a large pressure is applied near the rotating shaft of the winding means 5 due to the weight of the recording medium 2.

Further, as shown in FIG. 1, when the winding unit 5 winds the recording medium 2 fed from the paper feeding unit 3, the recording medium 2 is tensioned so that the recording is performed at the outer edge of the winding unit 5. Pressure can be applied to the medium 2. In this case, the pressure applied to the recording medium 2 can be adjusted by adjusting the tension acting on the recording medium 2. For example, the tension acting on the recording medium 2 can be adjusted by adjusting the rotational speeds of the paper feeding means 3 and the winding means 5.
In the example shown in FIG. 1, the case where roll paper is used as the recording medium is shown. However, in the image forming apparatus according to the present embodiment, other recording media may be used.

For example, in the image forming apparatus according to the present embodiment, the recording medium is wound in the form of a roll such as a continuous form folded at predetermined intervals or a continuous form in which cuttable perforations are formed at predetermined intervals. No continuous paper may be used.
In this way, when a recording medium other than roll paper is used, it is not necessary to wind up the recording medium, so that the winding means 5 shown in FIG. 1 can be omitted.

  That is, when continuous paper such as continuous paper or continuous paper is used as a recording medium, the recording medium after image formation can be folded and stacked along folds or perforations. In this case, pressure is applied to the image by the weight of the stacked recording media. Thus, when pressure is applied to an image by its own weight, a position where the own weight is generated in the image forming apparatus is defined as a pressurizing unit. For example, if continuous paper is stacked in a discharge portion where the recording medium is discharged and pressure is applied to the image by its own weight, the discharge portion corresponds to a pressurizing unit.

  In the image forming apparatus according to the present embodiment, not only continuous paper but also cut paper may be used as a recording medium. A cut sheet is an independent recording medium for each print unit (one page) in the conveyance direction during image formation. Even when cut paper is used, pressure can be applied to the image formed on the recording medium by laminating the recording media (cut paper) after image formation.

  In the image forming apparatus according to this embodiment, a pressurizing unit for applying pressure to the image formed on the recording medium may be provided separately. For example, it is possible to apply pressure to the image formed on the recording medium by providing rollers on each of the upper surface side and the lower surface side of the recording medium, and transporting the recording medium after the image formation between the rollers using these rollers. .

  Further, the image forming apparatus 1 winds the recording medium 2 after image formation by the winding unit 5, and then again applies ink (second ink) to the wound recording medium 2. You may comprise so that "reprinting" may be performed.

When reprinting is performed, the recording medium wound up by the winding unit 5 may be set on the paper feeding unit 3 again to form an image. At this time, the ink applying means for performing reprinting may be the same as the ink applying means 4 shown in FIG. 1 (in this case, the ink applying means 4 serves as the second ink applying means), or a separate ink applying means (first ink applying means). A second ink application unit) may be provided.
Note that the image forming apparatus 1 is not limited to the above-described means, and may include other means as necessary.

  Further, each unit such as the ink applying unit 4 and the winding unit 5 is not limited to being provided in the image forming apparatus 1 that is a single device, and for example, the ink applying unit 4 and the winding unit 5, etc. You may comprise so that each means may be disperse | distributing or straddling to a separate apparatus.

<Explanation regarding pressure applied to ink and image>
Next, the pressure applied to the ink used in the present embodiment and the image formed on the recording medium will be described in detail.
First, problems of conventional ink will be described.

An image formed with a conventional ink has an inferior anti-blocking property, an image being offset when a pressure is applied (an image is peeled off from a recording medium), an inferior anti-sliding property, and an image having high glossiness There was a problem that could not be obtained. The image forming apparatus of the present invention is based on the knowledge about the above problem.
The blocking resistance and rubbing resistance which are the subject of the present invention are related to the fixing property between the image and the recording medium. As an example, the resin particles can be added to the conventional ink to improve the fixability. However, the resin that can improve the fixability has high viscoelasticity, and logarithmic attenuation is achieved by adding the above resin. The maximum value of the rate will increase.

  Here, the logarithmic decay rate is a logarithmic decay rate when measured using a rigid pendulum test, and is a method for measuring a change in viscoelasticity of ink over time. Details of the logarithmic decay rate will be described later.

  When ink with a large maximum logarithmic decay rate is used, the ink has high viscoelasticity, so there is pressure on the image, such as when fixing using a fixing roller after image formation or when winding after printing on roll paper. The problem is that the image is offset at such timing. Also, by applying sufficient pressure to the image, it is possible to smooth the surface of the image and obtain an image with high glossiness, and to improve the rubbing resistance, but avoid image offset. In such a case, sufficient pressure cannot be applied, and an image having high gloss cannot be obtained.

  In addition, when an image forming apparatus using continuous paper is used, in the process of rewinding the continuous paper after image formation into a roll, a large pressure is applied to the image near the rotation axis of the roll, and the image is offset. Is a problem. Furthermore, when the continuous paper is tensioned and the image-formed paper is rewound into a roll, not only near the rotation axis of the roll but also at the outer edge of the roll, the image may be offset. It becomes.

  Further, when performing the above-described reprinting, if the winding pressure after the first image formation by the first ink application unit is large, the roll is uniformly wound, and the reprinting can be performed accurately. As a result, the image is offset. On the other hand, if the take-up pressure is low, the roll bends and becomes non-uniform, and recording misalignment due to the fact that the paper is not conveyed at a constant speed during reprinting becomes a problem. In addition, when the second ink applying unit forms an image on the same surface as the image formed by the first ink applying unit at the time of reprinting, compared to the case of forming an image on the opposite surface. Problems caused by misalignment are increased. This is because in the former case, in addition to the positional deviation that can occur in image formation by the second ink application unit, positional deviation can also occur between the image formed by the first ink application unit. However, as the second ink applying means in the present invention, means for forming an image on the surface opposite to the surface of the recording medium on which the image is formed by the first ink applying means is not excluded.

[Logarithmic decay rate]
Next, the logarithmic decay rate will be described in detail.
The ink used in the image forming apparatus according to the present embodiment has a maximum value when the logarithmic decay rate is 7200 seconds or less when an ink film formed using the ink is measured by a rigid pendulum test at 60 ° C. And the maximum value is 0.300 or less.

In particular, in the invention according to the present embodiment, the maximum value of the logarithmic decay rate is more preferably 0.055 or more and 0.293 or less, and further preferably 0.055 or more and 0.117 or less. Further, the time for which the logarithmic decay rate of the ink film takes the maximum value is preferably 400 seconds or more and 5000 seconds or less, and more preferably 400 seconds or more and 660 seconds or less.
As described above, when the maximum value of the logarithmic decay rate is 0.300 or less, stickiness of an image formed using ink is suppressed, and occurrence of blocking can be suppressed.

  Further, when the time when the logarithmic decay rate takes the maximum value is 7,200 seconds or less, the time when the stickiness of the image formed using the ink becomes maximum can be shortened. If the time when the stickiness is maximized can be shortened, the pressure can be applied to the image by the pressurizing means after the stickiness is sufficiently reduced. Therefore, for example, when the pressurizing unit is provided immediately after the first ink applying unit, or an image forming apparatus that is a high-speed printing machine with a short transport time between the first ink applying unit and the pressurizing unit The occurrence of blocking can be suppressed even in the case where is used. The time when the logarithmic decay rate takes the maximum value means the time from the start of measurement until the logarithmic decay rate reaches the maximum value.

As described above, in the image forming apparatus according to the present embodiment, the ink having the property that the maximum value of the logarithmic attenuation rate is 0.300 or less and the time for which the logarithmic attenuation rate takes the maximum value is 7,200 seconds or less. Therefore, blocking does not occur even when a pressure of 3.5 kg / cm ² or more and 16.0 kg / cm ² or less is applied after the image formation, and an image having excellent friction resistance and gloss can be obtained. In addition, since the image formed using the ink having such properties does not easily increase the stickiness of the image, the contact member such as a backing paper or a roller does not stick to the image, and the occurrence of blocking can be suppressed. . Further, since blocking does not occur, it is possible to wind the papers strongly, thereby improving the fixing property and improving the rubbing resistance. Moreover, the surface is smoothed by strongly winding papers, and glossiness can be improved.

Next, a specific method for measuring the logarithmic decay rate will be described.
In the method for measuring the logarithmic decay rate, a rigid pendulum type physical property tester (device name: RPT-3000W, manufactured by A & D Corporation) is used. 40 μL of ink is dropped on an aluminum substrate, and an ink film with a thickness of 100 μm is applied with a dedicated coating jig (PCT-100) for coating with a thickness of 100 μm. The obtained ink film is installed together with the cold block (CHB-100) within 15 seconds, and the cylinder edge (RBP-040) and the pendulum (FRB-100) are set. Also, set two FRB-100 exclusive weights at the bottom of the pendulum. The measurement temperature is raised from room temperature (25 ° C.) to 60 ° C. at a rate of 5 ° C./min, and thereafter kept at 60 ° C. Taking the time at room temperature (25 ° C.) as the measurement start time, the logarithmic decay rate is plotted against the time every 6 seconds. The obtained plot is smoothed, the maximum value is calculated, and the maximum value of the logarithmic decay rate is obtained. The maximum value of the logarithmic decay rate can be used as an index of tack force (stickiness).
The logarithmic decay rate (D ′ (n)) after smoothing can be obtained as follows when the logarithmic decay rate of the nth plot is defined as D (n).
D ′ (n) = {D (n−2) + D (n−1) + D (n) + D (n + 1) + D (n + 2)} / 5
D ′ (1) = D (1)
D ′ (2) = {D (1) + D (2)} / 2

FIG. 2 is a graph showing the relationship between the logarithmic decay rate and the elapsed time. As shown in FIG. 2, the maximum value of the logarithmic decay rate of Sample A exceeds 0.300. On the other hand, in Sample B, the maximum value of the logarithmic decay rate is 0.300 or less, and the time for which the maximum value of the logarithmic decay rate is maximum is 7,200 seconds or less. Like Sample B, the maximum value of the logarithmic attenuation rate is 0.300 or less, and the time for which the logarithmic attenuation rate takes the maximum value is 7,200 seconds or less, so that blocking resistance, rubbing resistance, and glossiness are obtained. Can be improved.
[Pressure applied to image by pressurizing means and pressurizing process]

The pressure applied to the image by the pressing means is 3.5 kg / cm ² or more and 16.0 kg / cm ² or less, and preferably 3.5 kg / cm ² or more and 5.8 kg / cm ² or less. When the pressure is 3.5 kg / cm ² or more, a highly glossy image can be obtained, and the rubbing resistance can be improved. When the pressure is 16.0 kg / cm ² or less, the image can be It is possible to prevent the blocking resistance from being deteriorated by offsetting the overlapping image or paper. In addition, there is no restriction | limiting in particular as a measuring method of a pressure, According to the objective, a well-known apparatus can be selected suitably. In addition, even when the pressure applied to the image by the pressurizing unit is generated by winding the continuous paper after applying the ink in a roll shape, there is no particular limitation on the method of measuring the pressure, and a publicly known method can be appropriately used depending on the purpose. A device can be selected. For example, apparatus name: I-SCAN5027 (made by Nitta Corporation) can be used.

  The pressure in the roll-shaped continuous paper can be calculated with reference to the diameter, height, and mass of the roll-shaped continuous paper from, for example, a photograph or information of the continuous paper wound in a roll shape.

  When the recording medium is continuous paper, the pressure applied to the image by the pressurizing unit is preferably generated by winding the continuous paper after applying ink into a roll (see FIG. 1). Further, the present invention corresponds to the present invention as long as at least one of the pressures is applied to a plurality of images in continuous paper.

  The maximum value of the logarithmic decay rate and the time for which the maximum value is reached are within a predetermined range. When a pressure within the predetermined pressure range is applied, no offset occurs and the anti-blocking property is good. Also, the rubbing resistance and gloss of the image can be improved. In addition, since a sufficient winding pressure is applied within the above pressure range, an additional effect that additional printing can be performed without any problem can be obtained.

  The maximum value of the logarithmic decay rate of the ink film and the time for which the logarithmic decay rate becomes the maximum value are particularly affected by the resin in the ink, the organic solvent, and the like. The type of resin, organic solvent, and the like, the amount of addition, and the like as examples that can realize the maximum value of the logarithmic decay rate and the time range in which the logarithmic decay rate takes the maximum value will be described in detail later.

<First ink>
Hereinafter, the organic solvent, water, color material, resin, additive, and the like used for the first ink will be described. In the present specification, the simple description of “ink” means “first ink”.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-he Polyhydric alcohols such as sundiol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, ethylene glycol mono Polyhydric alcohol alkyl ethers such as ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether, ethylene glycol mono Polyhydric alcohol aryl ethers such as benzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- -Nitrogen-containing heterocyclic compounds such as pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, Amides such as N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, Examples thereof include ethylene carbonate.
In addition to functioning as a wetting agent, it is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because good drying properties can be obtained.

A polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Specific examples of the glycol ether compound include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, tripropylene glycol monobutyl ether. Polyhydric alcohol alkyl ethers such as polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve ink permeability when paper is used as a recording medium.

ただし、前記一般式（１）中、Ｒ^１は、水素原子、又は炭素数１以上１０以下のアルキル基を表し、Ｒ^２、及びＲ^３は、それぞれ独立に、炭素数１以上１０以下のアルキル基を表し、ｎは１以上５以下の整数を表す。
前記一般式（１）中のＲ^１としては、水素原子、炭素数１以上１０以下のアルキル基であり、水素原子、メチル基が好ましい。
前記一般式（１）中のＲ^２としては、炭素数１以上１０以下のアルキル基であり、メチル基、エチル基が好ましい。
前記一般式（１）中のＲ^３としては、炭素数１以上１０以下のアルキル基であり、メチル基、エチル基、ブチル基が好ましい。
前記一般式（１）中のｎとしては、１以上５以下の整数であり、２以上３以下の整数が好ましい。 The organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. However, the organic solvent preferably includes an ether compound having no hydroxyl group, and includes a hydroxyl group represented by the following general formula (1). It is more preferable that the ether compound which does not have is included.

However, the general formula (1), ^{R 1} is a hydrogen atom, or represents a number from 1 to 10 alkyl group carbon, ^{R 2,} and ^{R 3} are each independently alkyl having 1 to 10 carbon atoms Represents a group, and n represents an integer of 1 to 5.
R ¹ in the general formula (1) is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably a hydrogen atom or a methyl group.
R ² in the general formula (1) is an alkyl group having 1 to 10 carbon atoms, preferably a methyl group or an ethyl group.
R ³ in the general formula (1) is an alkyl group having 1 to 10 carbon atoms, preferably a methyl group, an ethyl group, or a butyl group.
In the general formula (1), n is an integer of 1 to 5, preferably 2 or more and 3 or less.

  There is no restriction | limiting in particular as an ether compound represented by the said General formula (1), Although it can select suitably according to the objective, Triethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether Dipropylene glycol ethyl methyl ether is preferred.

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of the drying property and ejection reliability of the ink, 20 mass% or more and 60 mass% or less are more preferable.

<Resin>
The type of resin contained in the ink is not particularly limited and can be appropriately selected according to the purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene type Resin, styrene-butadiene resin, vinyl chloride resin, styrene acrylic resin, acrylic silicone resin, polyrotaxane resin, etc.

  Resin particles made of these resins may be used. An ink can be obtained by mixing resin particles with a material such as a colorant or an organic solvent in a resin emulsion state in which water is dispersed as a dispersion medium. As said resin particle, what was synthesize | combined suitably may be used and a commercial item may be used. Moreover, these may be used individually by 1 type, or may be used in combination of 2 or more types of resin particles. In view of obtaining a uniform image, it is preferable to use a styrene acrylic resin alone, a urethane resin alone, or a combination of a urethane resin and a polyrotaxane resin as the resin particles.

-Urethane resin particles-
The urethane resin particles are made of polyurethane, and the polyurethane is obtained by urethane bonding of an isocyanate compound having a plurality of isocyanate groups and a polyol compound having a plurality of hydroxyl groups. Each of the isocyanate compound and the polyol compound may itself be a polymer compound.

--Isocyanate compound--
The isocyanate compound having a plurality of isocyanate groups used in the polyurethane is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include bifunctional isocyanate compounds, trifunctional isocyanate compounds, and tetrafunctional isocyanate compounds. . These may be used individually by 1 type and may use 2 or more types together.

  Examples of the bifunctional isocyanate compound include isophorodiisocyanate, cyclohexane diisocyanate, 1,6-hexane diisocyanate, 1,4-butane diisocyanate, 1,4-benzene diisocyanate, diphenylmethane diisocyanate, and the like.

  Examples of the trifunctional isocyanate compound include 1,3,5-cyclohexane triisocyanate, 1,4,8-octane triisocyanate, and 1,3,5-benzene triisocyanate.

  Examples of the tetrafunctional isocyanate compound include 1,2,5,6-cyclohexanetetraisocyanate.

  Among these, although there are differences in mechanical strength and weather resistance obtained by synthesizing urethane using them, isophorodiisocyanate and cyclohexane diisocyanate are preferable from the viewpoints of mass production handling, environmental protection, and physical property operation.

--Polyol compound--
The polyol compound is not particularly limited and may be appropriately selected depending on the intended purpose. For example, alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol , 1,6-hexanediol); alkylene ether glycol (diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diol (1,4-cyclohexanedimethanol) Hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.); alkylene oxides of the above alicyclic diols (ethylene oxide, propylene) Oxide, butylene oxide, etc.) adducts; 4,4′-dihydroxybiphenyls (3,3′-difluoro-4,4′-dihydroxybiphenyl etc.); bis (hydroxyphenyl) alkanes (bis (3-fluoro-4) -Hydroxyphenyl) methane, 1-phenyl-1,1-bis (3-fluoro-4-hydroxyphenyl) ethane, 2,2-bis (3-fluoro-4-hydroxyphenyl) propane, 2,2-bis ( 3,5-difluoro-4-hydroxyphenyl) propane (alias: tetrafluorobisphenol A), 2,2-bis (3-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane); Bis (4-hydroxyphenyl) ethers (such as bis (3-fluoro-4-hydroxyphenyl) ether); Alkylene oxide phenols (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. These may be used individually by 1 type and may use 2 or more types together.

Examples of the polyol compound include carbonate-based polyols, ester-based polyols, and ether-based polyols. These may be used individually by 1 type and may use 2 or more types together. Each of these has two or more hydroxyl groups in the polyol compound.
The polyol compound preferably has a hydroxyl group at both ends of the compound for synthesis.

The carbonate polyol is preferably a compound represented by the following general formula (A).

The ester polyol is preferably a compound represented by the following general formula (B).

The ether polyol is preferably a compound represented by the following general formula (C).

  However, in the general formulas (A) to (C), each R independently includes various skeletons such as a hexamethylene group, a cyclohexane group, a phenylene group, a tetramethylene group, a cyclohexanedimethylene group, and a cyclohexanemonomethylene group. However, the examples are not limited to the examples. Moreover, n is 1-20.

The volume average particle diameter of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 nm or more and 1,000 nm or less from the viewpoint of obtaining good fixability and high image hardness. It is more preferably 200 nm or less and particularly preferably 10 nm or more and 100 nm or less.
The volume average particle diameter can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

  The resin content is not particularly limited and may be appropriately selected according to the purpose. However, from the viewpoint of fixability and ink storage stability, the content of the resin is 1% by mass or more and 30% by mass or less. Is preferable, and 5 mass% or more and 20 mass% or less are more preferable.

  The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of improving the image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number is converted. Is preferably 20 nm to 1000 nm, and more preferably 20 nm to 150 nm. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

[Mass ratio (ether compound / urethane resin particles)]
The mass ratio (ether compound / urethane resin particles) between the content (% by mass) of the urethane resin particles and the content (% by mass) of the ether compound having no hydroxyl group is 0.40 or more and 1.60. Or less, more preferably 0.60 or more and 1.40 or less, and particularly preferably 0.80 or more and 1.20 or less. When the mass ratio (ether compound / urethane resin particles) is 0.40 or more and 1.60 or less, the maximum value of the logarithmic decay rate is 0.300 or less, and the time for which the logarithmic decay rate is the maximum value is 7 , It is easy to make it 200 seconds or less.

<Copper phthalocyanine pigment>
A copper phthalocyanine pigment can be used as the color material.
Phthalocyanine pigments are planar molecules and are easy to obtain molecular crystals. In order to take a molecular crystal, the force that removes the solvent from the intermolecular force acts and is pushed out of the crystal. When the solvent is extruded onto the surface that is easy to dry, the drying property is improved and the logarithmic decay rate is hardly increased.

  As a copper phthalocyanine pigment, it may be used individually by 1 type and may use 2 or more types together. A mixed crystal may be used.

  In addition to the copper phthalocyanine pigment, black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver, and metallic pigments can be used for complementary colors. .

  Examples of copper phthalocyanine pigments include C.I. I. Pigment blue 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, C.I. I. Pigment green 7, 36, and the like.

  Specific examples of the pigment for the complementary color include black for carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI). Pigment black 11), metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1). Further, for color use, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Green 1, 4, 8, 10, 17, 18, etc.

  The content of the copper phthalocyanine pigment in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass from the viewpoints of improvement in image density, good fixability and ejection stability. % Or less.

  In order to disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of dispersing the pigment surface by coating with a resin, a method of dispersing using a dispersant, Etc.

  As a method for introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a self-dispersing pigment that can be dispersed in water by adding a functional group such as a sulfone group or a carboxyl group to the pigment can be used.

As a method for coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is included in microcapsules and can be dispersed in water can be used. This can be paraphrased as a resin-coated pigment. In this case, it is not necessary that all pigments blended in the ink are coated with a resin, and within a range where the effects of the present invention are not impaired, uncoated pigments and partially coated pigments are dispersed in the ink. It may be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular type dispersant or high-molecular type dispersant represented by a surfactant.

As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and naphthalenesulfonic acid Na formalin condensate can also be suitably used as a dispersant.
A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
An ink can be obtained by mixing a material such as water or an organic solvent with a pigment. Further, it is also possible to produce an ink by mixing a pigment, other water, a dispersant, and the like into a pigment dispersion and mixing a material such as water or an organic solvent.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. For dispersion, a disperser is preferably used.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of maximum number because the pigment dispersion stability is good and the image quality such as ejection stability and image density is also high. 500 nm or less is preferable and 20 nm or more and 150 nm or less are more preferable. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining good ejection stability and increasing the image density, 0.1% by mass. % To 50% by mass is preferable, and 0.1% to 30% by mass is more preferable.
The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator or the like, if necessary.

<Water>
The water content in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 90% by mass or less, and 20% by mass from the viewpoint of ink drying property and ejection reliability. % To 60% by mass is more preferable.

<Additives>
If necessary, a surfactant, an antifoaming agent, an antiseptic / antifungal agent, a rust inhibitor, a pH adjuster, and the like may be added to the ink.

<Surfactant>
As the surfactant, any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants and anionic surfactants can be used.
There is no restriction | limiting in particular in silicone type surfactant, According to the objective, it can select suitably. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, and side chain both terminal modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as an aqueous surfactant. In addition, as the silicone surfactant, a polyether-modified silicone surfactant can be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.
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 the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylate. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.
Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.
These may be used alone or in combination of two or more.

一般式（Ｓ−１）
（但し、一般式（Ｓ-1）式中、ｍ、ｎ、ａ、及びｂは、それぞれ独立に、整数を表わし、Ｒは、アルキレン基を表し、Ｒ’は、アルキル基を表す。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ−６１８、ＫＦ−６４２、ＫＦ−６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ−ＳＳ−５６０２、ＳＳ−１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ−２１０５、ＦＺ−２１１８、ＦＺ−２１５４、ＦＺ−２１６１、ＦＺ−２１６２、ＦＺ−２１６３、ＦＺ−２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ−３３、ＢＹＫ−３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）などが挙げられる。 The silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side Since both ends of the chain are modified with polydimethylsiloxane, a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibits good properties as an aqueous surfactant. preferable.
As such a surfactant, an appropriately synthesized product or a commercially available product may be used. Commercially available products can be obtained from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.
The polyether-modified silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyalkylene oxide structure represented by the general formula (S-1) is represented by Examples thereof include those introduced into the side chain of Si part of siloxane.

Formula (S-1)
(In the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R ′ represents an alkyl group.)
A commercial item can be used as said polyether modified silicone type surfactant, For example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Bic Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

一般式（Ｆ−１）
上記一般式（Ｆ−１）で表される化合物において、水溶性を付与するためにｍは０〜１０の整数が好ましく、ｎは０〜４０の整数が好ましい。
一般式（Ｆ-２）
Ｃ_ｎＦ_2ｎ+1−ＣＨ₂ＣＨ（ＯＨ）ＣＨ₂−Ｏ−（ＣＨ₂ＣＨ₂Ｏ）_ａ−Ｙ
上記一般式（Ｆ-２）で表される化合物において、ＹはＨ、又はＣｍＦ_２ｍ＋１でｍは1〜6の整数、又はＣＨ_２ＣＨ（ＯＨ）ＣＨ_２−ＣｍＦ_２ｍ＋１でｍは4〜６の整数、又はＣｐＨ_２ｐ＋１でｐは１〜１９の整数である。ｎは１〜６の整数である。ａは４〜１４の整数である。
上記のフッ素系界面活性剤としては市販品を使用してもよい。 この市販品としては、例えば、サーフロンＳ−１１１、Ｓ−１１２、Ｓ−１１３、Ｓ−１２１、Ｓ−１３１、Ｓ−１３２、Ｓ−１４１、Ｓ−１４５（いずれも、旭硝子株式会社製）；フルラードＦＣ−９３、ＦＣ−９５、ＦＣ−９８、ＦＣ−１２９、ＦＣ−１３５、ＦＣ−１７０Ｃ、ＦＣ−４３０、ＦＣ−４３１（いずれも、住友スリーエム株式会社製）；メガファックＦ−４７０、Ｆ−１４０５、Ｆ−４７４（いずれも、大日本インキ化学工業株式会社製）；ゾニール（Ｚｏｎｙｌ）ＴＢＳ、ＦＳＰ、ＦＳＡ、ＦＳＮ−１００、ＦＳＮ、ＦＳＯ−１００、ＦＳＯ、ＦＳ−３００、ＵＲ、キャプストーンＦＳ−３０、ＦＳ−３１、ＦＳ−３１００、ＦＳ−３４、ＦＳ−３５（いずれも、Ｃｈｅｍｏｕｒｓ社製）；ＦＴ−１１０、ＦＴ−２５０、ＦＴ−２５１、ＦＴ−４００Ｓ、ＦＴ−１５０、ＦＴ−４００ＳＷ（いずれも、株式会社ネオス社製）、ポリフォックスＰＦ−１３６Ａ，ＰＦ−１５６Ａ、ＰＦ−１５１Ｎ、ＰＦ−１５４、ＰＦ−１５９（オムノバ社製）、ユニダインＤＳＮ-４０３Ｎ（ダイキン工業株式会社製）などが挙げられ、これらの中でも、良好な印字品質、特に発色性、紙に対する浸透性、濡れ性、均染性が著しく向上する点から、Ｃｈｅｍｏｕｒｓ社製のＦＳ−３１００、ＦＳ−３４、ＦＳ−３００、株式会社ネオス製のＦＴ−１１０、ＦＴ−２５０、ＦＴ−２５１、ＦＴ−４００Ｓ、ＦＴ−１５０、ＦＴ−４００ＳＷ、オムノバ社製のポリフォックスＰＦ−１５１Ｎ及びダイキン工業株式会社製のユニダインＤＳＮ-４０３Ｎが特に好ましい。 As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of the fluorosurfactant include perfluoroalkyl phosphate compounds, perfluoroalkylethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain. Among these, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain are preferred because of their low foaming properties, and are particularly fluorine-based compounds represented by the general formulas (F-1) and (F-2). A surfactant is preferred.

Formula (F-1)
In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
General formula (F-2)
_{C n F 2n + 1- CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y
In the compound represented by the general formula (F-2), Y is H, or CmF _{2m + 1} , m is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ —CmF _{2m + 1,} where m is 4 to 6. An integer, or CpH _{2p + 1} , p is an integer of 1-19. n is an integer of 1-6. a is an integer of 4-14.
A commercial item may be used as said fluorosurfactant. As this commercial item, for example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, 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, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT-250 FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (Omnova) Manufactured), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) and the like. Among these, good print quality, particularly color developability, penetrability to paper, wettability, and leveling are significantly improved. FS-3100, FS-34, FS-300 manufactured by Chemours, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd. Particularly preferred are Fox PF-151N and Unidyne DSN-403N manufactured by Daikin Industries, Ltd.

  There is no restriction | limiting in particular as content of surfactant in an ink, Although it can select suitably according to the objective, From the point which is excellent in wettability and discharge stability, and image quality improves, it is 0.001 mass. % To 5% by mass is preferable, and 0.05% to 5% by mass is more preferable.

<Antifoaming agent>
There is no restriction | limiting in particular as an antifoamer, For example, a silicone type antifoamer, a polyether type | system | group antifoamer, a fatty-acid ester type | system | group antifoamer etc. are mentioned. These may be used alone or in combination of two or more. Among these, a silicone type antifoaming agent is preferable from the viewpoint of excellent foam breaking effect.

<Antiseptic and antifungal agent>
The antiseptic / antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Rust preventive>
There is no restriction | limiting in particular as a rust preventive agent, For example, acidic sulfite, sodium thiosulfate, etc. are mentioned.

<PH adjuster>
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

There is no restriction | limiting in particular as a physical property of an ink, According to the objective, it can select suitably, For example, it is preferable that a viscosity, surface tension, pH, etc. are the following ranges.
The viscosity at 25 ° C. of the ink is preferably 5 mPa · s or more and 30 mPa · s or less, preferably 5 mPa · s or more and 25 mPa · s or less from the viewpoint of improving the printing density and character quality and obtaining good discharge properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. Measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid amount 1.2 mL, rotation speed 50 rpm, and measurement is possible for 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less and more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is suitably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12 and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

<Second ink>
Hereinafter, the organic solvent, water, coloring material, resin, additive, and the like used for the second ink will be described, but the components not described are the same as those of the first ink. The second ink may be the same as or different from the first ink.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-he Polyhydric alcohols such as sundiol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, ethylene glycol mono Polyhydric alcohol alkyl ethers such as ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether, ethylene glycol mono Polyhydric alcohol aryl ethers such as benzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- -Nitrogen-containing heterocyclic compounds such as pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, Amides such as N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, Examples thereof include ethylene carbonate.
In addition to functioning as a wetting agent, it is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because good drying properties can be obtained.

A polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of ethers include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
The polyol compound having 8 or more carbon atoms and the glycol ether compound can improve the permeability of the second ink when paper is used as a recording medium.

  The content of the organic solvent in the second ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of the drying property and ejection reliability of the second ink, it is 10% by mass or more and 60%. % By mass or less is preferable, and 20% by mass or more and 60% by mass or less is more preferable.

<Color material>
The color material is not particularly limited, and pigments and dyes can be used.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used alone or in combination of two or more. A mixed crystal may be used.
As the pigment, for example, a black pigment, a yellow pigment, a magenta pigment, a cyan pigment, a white pigment, a green pigment, an orange pigment, a glossy pigment such as gold or silver, a metallic pigment, or the like can be used.
Carbon black produced by known methods such as contact method, furnace method, thermal method in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow as inorganic pigments Can be used.
Organic pigments include azo pigments, polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments). Dye chelates (for example, basic dye type chelates, acidic dye type chelates), nitro pigments, nitroso pigments, aniline black, and the like can be used. Of these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of pigments include black for carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11). And metal pigments such as titanium oxide and organic pigments such as aniline black (CI Pigment Black 1).
Further, for color use, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3, 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and an acid dye, a direct dye, a reactive dye, and a basic dye can be used. One kind may be used alone, or two or more kinds may be used in combination.
Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive black 3, 4, and 35 are mentioned.

  The content of the color material in the second ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more, from the viewpoints of improvement in image density, good fixability and ejection stability. It is 10 mass% or less.

In order to obtain the second ink by dispersing the pigment, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of coating and dispersing the pigment surface with a resin, and a dispersant are used. And a method of dispersing them.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a method of making it dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to the pigment (for example, carbon) Is mentioned.
As a method for coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is included in microcapsules and dispersible in water can be mentioned. This can be paraphrased as a resin-coated pigment. In this case, it is not necessary for the pigment blended in the second ink to be entirely coated with resin, and within the range where the effect of the present invention is not impaired, the pigment that is not coated or the partially coated pigment is the second. May be dispersed in the ink.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular type dispersant or high-molecular type dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and naphthalenesulfonic acid Na formalin condensate can also be suitably used as a dispersant.
A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
It is possible to obtain a second ink by mixing a material such as water or an organic solvent with the pigment. It is also possible to produce a second ink by mixing a pigment, other water, a dispersant, or the like into a pigment dispersion and mixing a material such as water or an organic solvent.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. For dispersion, a disperser is preferably used.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of maximum number because the pigment dispersion stability is good and the image quality such as ejection stability and image density is also high. 500 nm or less is preferable and 20 nm or more and 150 nm or less are more preferable. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining good ejection stability and increasing the image density, 0.1% by mass. % To 50% by mass is preferable, and 0.1% to 30% by mass is more preferable.
The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator or the like, if necessary.

<Resin>
The type of resin contained in the second ink is not particularly limited and can be appropriately selected according to the purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin Butadiene-based resin, styrene-butadiene-based resin, vinyl chloride-based resin, acrylic styrene-based resin, acrylic silicone-based resin, and the like.
Resin particles made of these resins may be used. The resin particles can be mixed with a material such as a coloring material or an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium to obtain a second ink. As said resin particle, what was synthesize | combined suitably may be used and a commercial item may be used. Moreover, these may be used individually by 1 type, or may be used in combination of 2 or more types of resin particles.

The volume average particle diameter of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 nm or more and 1,000 nm or less from the viewpoint of obtaining good fixability and high image hardness. It is more preferably 200 nm or less and particularly preferably 10 nm or more and 100 nm or less.
The volume average particle diameter can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

  The content of the resin is not particularly limited and may be appropriately selected depending on the purpose. However, from the viewpoint of fixability and storage stability of the second ink, the content of the resin is 1 mass relative to the total amount of the second ink. % To 30% by mass is preferable, and 5% to 20% by mass is more preferable.

  The particle size of the solid content in the second ink is not particularly limited and can be appropriately selected according to the purpose. However, in terms of increasing the image quality such as ejection stability and image density, the maximum number is converted. The maximum frequency is preferably 20 nm or more and 1000 nm or less, and more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

<Recording medium>
The recording medium used for recording is not particularly limited, and examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper.

  In particular, the recording medium capable of obtaining the effect in the present invention has a support and a coating layer provided on at least one surface side of the support, and further has other layers as necessary. Examples include recording media.

A recording medium having the support and the coating layer is generally called a coated paper and is known as a recording medium having low ink permeability. Although it is difficult to firmly fix the coloring material on a recording medium having low permeability such as coated paper, the blocking resistance and the rubbing resistance are often deteriorated. If the maximum value of the logarithmic decay rate at 60 ° C. measured by the test is 0.300 or less and the time for which the maximum value of the logarithmic decay rate is 7200 seconds or less, it is 3.5 kg / cm after image formation. even by applying a pressure of ^more than 16.0 kg / cm ² or less it does not occur blocking, also particularly preferred for耐摺rubbing resistance and gloss is obtained a good image by pressured.

In the recording medium having the support and the coating layer, the transfer amount of pure water to the recording medium at a contact time of 100 ms measured with a dynamic scanning absorption meter is 2 mL / m ² or more and 35 mL / m ² or less. Is preferably 2 mL / m ² or more and 10 mL / m ² or less.

  If the transfer amount of the ink and pure water at the contact time of 100 ms is too small, beading is likely to occur. If it is too large, the ink dot diameter after image formation is too smaller than the desired diameter. Sometimes.

Transfer amount to the recording medium of pure water at the contacting time 400ms measured by a dynamic scanning absorptometer, preferably 3 mL / ^{m 2} or more 40 mL / ^{m 2} or less, 3 mL / ^{m 2} or more 10 mL / ^{m 2} or less More preferred.

  When the amount of transfer at the contact time of 400 ms is small, the drying property is insufficient, and thus spur marks are likely to occur. When the amount is too large, the gloss of the image portion after drying is likely to be low. is there. The amount of pure water transferred to the recording medium at the contact time of 100 ms and 400 ms can be measured on the surface of the recording medium having the coated layer.

  Here, the dynamic scanning absorptiometer (DSA, Kojipa Gakkai, Vol. 48, May 1994, pp. 88-92, Kuju Shigenori) absorbs liquid in a very short time. It is a device that can measure the amount accurately. The dynamic scanning absorption meter reads the liquid absorption speed directly from the movement of the meniscus in the capillary, makes the sample a disk, and then scans the liquid absorption head in a spiral shape, and the scanning speed according to a preset pattern. Is automatically changed by a method in which the number of necessary points is measured with one sample.

  A liquid supply head for a paper sample is connected to a capillary via a Teflon (registered trademark) tube, and the position of the meniscus in the capillary is automatically read by an optical sensor. Specifically, the transfer amount of pure water or ink can be measured using a dynamic scanning absorption meter (K350 series D type, manufactured by Kyowa Seiko Co., Ltd.).

The transfer amount at the contact time of 100 ms and the contact time of 400 ms can be obtained by interpolation from the measured value of the transfer amount at the contact time adjacent to each contact time.
-Support-

The support is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paper based on wood fibers, and sheet-like materials such as non-woven fabrics mainly composed of wood fibers and synthetic fibers. .
There is no restriction | limiting in particular as said paper, According to the objective, it can select suitably according to the objective, For example, wood pulp, waste paper pulp, etc. are used.

  Examples of the wood pulp include hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), NBSP, LBSP, GP, and TMP.

  As the raw material of the used paper pulp, the white paper, ruled white, cream white, card, special white, medium white, imitation, fair white, Kent, white, as shown in the used paper standard quality standard table of the used paper recycling promotion center Art, special upper limit, another upper limit, newspaper, magazine, etc. are mentioned.

Specifically, printer paper such as non-coating computer paper, thermal paper, and pressure-sensitive paper as information-related paper; OA waste paper such as PPC paper; coating of art paper, coated paper, finely coated paper, matte paper, etc. Paper: High quality paper, color quality, notebook, notepaper, wrapping paper, fancy paper, medium quality paper, newsprint, reprint paper, super paper, imitation paper, pure white roll paper, uncoated paper such as milk carton, etc. Examples of used paper and paperboard include chemical pulp paper and high-yield pulp-containing paper.
These may be used individually by 1 type and may use 2 or more types together.
The waste paper pulp can be generally produced from a combination of the following four steps.
(1) For disaggregation, waste paper is treated with mechanical force and chemicals with a pulper to loosen it into a fibrous form, and the printing ink is peeled from the fiber.
(2) Dust removal is to remove foreign matter (plastic etc.) and dust contained in waste paper with a screen, cleaner or the like.
(3) In the deinking, the printing ink peeled off from the fiber using a surfactant is removed from the system by a flotation method or a cleaning method.
(4) Bleaching increases the whiteness of the fiber using an oxidizing action or a reducing action.
When mixing the used paper pulp, the mixing ratio of the used paper pulp in the total pulp is preferably 40% or less from the viewpoint of curling after image formation.
As the internal filler used for the support, for example, a conventionally known pigment is used as a white pigment.

  Examples of the white pigment include light calcium carbonate, heavy calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, White inorganic pigments such as calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, lithopone, zeolite, magnesium carbonate, magnesium hydroxide; styrene plastic pigment, acrylic plastic pigment, polyethylene, microcapsule, urea resin And organic pigments such as melamine resin. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the internally added sizing agent used for making the support include neutral rosin sizing agents used for neutral papermaking, alkenyl succinic anhydride (ASA), alkyl ketene dimer (AKD), and petroleum resins. System sizing agents and the like. Among these, a neutral rosin sizing agent or alkenyl succinic anhydride is particularly preferable. The alkyl ketene dimer has a small size effect, so the addition amount may be small. However, since the friction coefficient on the surface of the recording paper (recording medium) decreases and becomes slippery, it is not preferable from the viewpoint of transportability during ink jet recording. There is a case.

-Coating layer-
The coating layer contains a pigment and a binder (binder), and further contains a surfactant and other components as necessary. In the present invention, the coating layer only needs to contain a pigment and a binder (binder) as described above, and there is no limitation on the formation method such as whether or not the coating layer is actually applied. Means things.
As the pigment, an inorganic pigment or a combination of an inorganic pigment and an organic pigment can be used.

  Examples of the inorganic pigment include kaolin, talc, heavy calcium carbonate, light calcium carbonate, calcium sulfite, amorphous silica, titanium white, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, Examples thereof include zinc hydroxide and chlorite. Among these, kaolin is particularly preferable because it has excellent glossiness and can be made close to a paper for offset printing.

  The kaolin includes delaminated kaolin, calcined kaolin, engineered kaolin by surface modification, etc. In consideration of gloss expression, the particle size distribution is such that the ratio of the particle size is 2 μm or less is 80% by mass or more. It is preferable that the kaolin which has occupies 50 mass% or more of the whole kaolin.

  The kaolin content is preferably 50 parts by mass or more with respect to 100 parts by mass of the binder. Glossiness can be improved as the said addition amount is 50 mass parts or more. The upper limit of the content is not particularly limited, but is preferably 90 parts by mass or less from the viewpoint of coating suitability in consideration of the fluidity of kaolin, particularly the thickening under high shear force.

  Examples of the organic pigment include water-soluble dispersions such as styrene-acrylic copolymer particles, styrene-butadiene copolymer particles, polystyrene particles, and polyethylene particles. Two or more of these organic pigments may be mixed.

  The addition amount of the organic pigment is preferably 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the total pigment in the coating layer. Since the organic pigment is excellent in gloss expression and its specific gravity is smaller than that of an inorganic pigment, it is possible to obtain a coating layer that is bulky, high gloss, and has good surface coverage. When the content is 2 parts by mass or more, the effect can be improved. When the content is 20 parts by mass or less, the fluidity of the coating liquid is excellent, the coating operability can be improved, and it is economical in terms of cost. is there.

In the form of the organic pigment, there are a solid type, a hollow type, a donut type, and the like, but the average particle diameter of the organic pigment is in consideration of the balance of gloss development, surface covering property and fluidity of the coating liquid. Is preferably 0.2 μm or more and 3.0 μm or less, and more preferably a hollow type having a porosity of 40% or more.
As the binder, an aqueous resin is preferably used.
As the aqueous resin, at least one of a water-soluble resin and a water-dispersible resin is preferably used.

  There is no restriction | limiting in particular as said water-soluble resin, According to the objective, it can select suitably, For example, modified products of polyvinyl alcohol, such as polyvinyl alcohol, anion modified polyvinyl alcohol, cation modified polyvinyl alcohol, acetal modified polyvinyl alcohol; Polyurethane; polyvinylpyrrolidone and polyvinylpyrrolidone and vinyl acetate copolymer, vinylpyrrolidone and dimethylaminoethyl / methacrylic acid copolymer, quaternized vinylpyrrolidone / dimethylaminoethyl / methacrylic acid copolymer, vinylpyrrolidone and Modified products of polyvinylpyrrolidone such as a copolymer of methacrylamidopropyl trimethylammonium chloride; Cellulo such as carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose Modified products of cellulose such as cationized hydroxyethyl cellulose; Synthetic resins such as polyester, polyacrylic acid (ester), melamine resin, or modified products thereof, polyester and polyurethane copolymer; poly (meth) acrylic acid, Examples include poly (meth) acrylamide, oxidized starch, phosphate esterified starch, self-modified starch, cationized starch, or various modified starches, polyethylene oxide, sodium polyacrylate, and sodium alginate. These may be used individually by 1 type and may use 2 or more types together.

  Among these, from the viewpoint of ink absorbability, polyvinyl alcohol, cation-modified polyvinyl alcohol, acetal-modified polyvinyl alcohol, polyester, polyurethane, and a copolymer of polyester and polyurethane are preferable.

  The water-dispersible resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyvinyl acetate, ethylene-vinyl acetate copolymer, polystyrene, styrene- (meth) acrylate ester copolymer Polymer, (meth) acrylic acid ester polymer, vinyl acetate- (meth) acrylic acid (ester) copolymer, styrene-butadiene copolymer, ethylene-propylene copolymer, polyvinyl ether, silicone-acrylic copolymer Coalescence, etc. Further, it may contain a crosslinking agent such as methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, or isocyanate, or may be a copolymer containing units such as N-methylolacrylamide and having a self-crosslinking property. A plurality of these water-based resins can be used simultaneously.

  The content of the aqueous resin is preferably 2 parts by mass or more and 100 parts by mass or less, and more preferably 3 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the pigment. The content is determined so that the liquid absorption characteristics of the recording medium fall within a desired range.

  When a water-dispersible colorant is used as the colorant, the cationic organic compound is not necessarily added, but is not particularly limited and can be appropriately selected and used depending on the purpose. For example, a primary to tertiary amine, quaternary ammonium salt monomer or oligomer that reacts with a sulfonic acid group, a carboxyl group, an amino group, or the like in a direct dye or acidic dye in water-soluble ink to form an insoluble salt. A polymer etc. are mentioned, Among these, an oligomer or a polymer is preferable.

  Examples of the cationic organic compound include dimethylamine / epichlorohydrin polycondensate, dimethylamine / ammonia / epichlorohydrin condensate, poly (trimethylaminoethyl methacrylate / methyl sulfate), diallylamine hydrochloride / acrylamide copolymer, (Diallylamine hydrochloride / sulfur dioxide), polyallylamine hydrochloride, poly (allylamine hydrochloride / diallylamine hydrochloride), acrylamide / diallylamine copolymer, polyvinylamine copolymer, dicyandiamide, dicyandiamide / ammonium chloride / urea / formaldehyde condensate , Polyalkylene polyamine dicyandiamide ammonium salt condensate, dimethyl diallyl ammonium chloride, polydiallyl methylamine hydrochloride, poly (diallyl dimethyl ester) Ruammonium chloride), poly (diallyldimethylammonium chloride / sulfur dioxide), poly (diallyldimethylammonium chloride / diallylamine hydrochloride derivative), acrylamide / diallyldimethylammonium chloride copolymer, acrylate / acrylamide / diallylamine hydrochloride copolymer Products, ethyleneimine derivatives such as polyethyleneimine and acrylicamine polymer, and polyethyleneimine alkylene oxide modified products. These may be used individually by 1 type and may use 2 or more types together.

  Among these, low molecular weight cationic organic compounds such as dimethylamine / epichlorohydrin polycondensate and polyallylamine hydrochloride and other relatively high molecular weight cationic organic compounds such as poly (diallyldimethylammonium chloride) It is preferable to use in combination. The combined use improves the image density and further reduces feathering compared to the single use.

  The cation equivalent of the cationic organic compound by colloid titration method (using polyvinyl potassium sulfate and toluidine blue) is preferably 3 meq / g or more and 8 meq / g or less. If the cation equivalent is within this range, good results can be obtained within the dry adhesion range.

  Here, in the measurement of the cation equivalent by the colloid titration method, the cationic organic compound is diluted with distilled water so as to have a solid content of 0.1% by mass, and pH adjustment is not performed.

The dry adhesion amount of the cationic organic compound is preferably 0.3 g / m ² or more and 2.0 g / m ² or less. When the dry adhesion amount of the cationic organic compound is 0.3 g / m ² or more and 2.0 g / m ² or less, the image density can be sufficiently improved and the effect of reducing feathering can be improved.

  The surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant is used. be able to. Among these, nonionic surfactants are particularly preferable. By adding the surfactant, the water resistance of the image is improved, the image density is increased, and bleeding is improved.

  Examples of the nonionic surfactant include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher aliphatic amine ethylene oxide adducts, and fatty acids. Amide ethylene oxide adduct, fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, fatty acid ester of glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol And fatty acid amides of alkanolamines. These may be used individually by 1 type and may use 2 or more types together.

  The polyhydric alcohol is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include glycerol, trimethylolpropane, pentaerythritol, sorbitol, and sucrose.

As the ethylene oxide adduct, it is also effective to substitute a part of ethylene oxide with an alkylene oxide such as propylene oxide or butylene oxide as long as water solubility can be maintained. The substitution rate is preferably 50% or less.
The HLB (hydrophilic / lipophilic ratio) of the nonionic surfactant is preferably 4 or more and 15 or less, and more preferably 7 or more and 13 or less.

  The addition amount of the surfactant is preferably 0 parts by mass or more and 10 parts by mass or less, and more preferably 0.1 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the cationic organic compound.

  Other components can be added to the coating layer as necessary, as long as the objects and effects of the present invention are not impaired. As said other component, additives, such as an alumina powder, a pH adjuster, antiseptic | preservative, antioxidant, etc. are mentioned.

  There is no restriction | limiting in particular as a formation method of the said coating layer, According to the objective, it can select suitably, It can carry out by the method of impregnating or apply | coating a coating layer liquid on the said support body. The impregnation or coating method of the coating layer liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, conventional size press, gate roll size press, film transfer size press, blade coater, rod coater It is possible to coat with various coating machines such as air knife coater and curtain coater, but from the viewpoint of cost, conventional size press, gate roll size press, film transfer size press etc. installed in paper machine It may be impregnated or coated and finished on-machine.

The adhesion amount of the coating layer liquid is not particularly limited and may be appropriately selected depending on the purpose, the solid content, 0.5 g / ^{m 2} or more 20 g / ^{m 2} or less is preferable, 1 g / m ² or more and 15 g / m ² or less are more preferable.

  After the impregnation or coating, drying may be performed as necessary. In this case, the drying temperature is not particularly limited and may be appropriately selected depending on the intended purpose. Is preferred.

  The recording medium may further have a back layer on the back surface of the support, between the support and the coating layer, or another layer between the support and the back layer, and a protective layer on the coating layer. It can also be provided. Each of these layers may be a single layer or a plurality of layers.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

  The “maximum value of logarithmic decay rate” and “the time for which the logarithmic decay rate takes the maximum value” used in the following examples and comparative examples were measured as follows.

(The maximum value of the logarithmic decay rate and the time when the logarithmic decay rate takes the maximum value)
The maximum value of the logarithmic decay rate and the time for which the logarithmic decay rate takes the maximum value were measured using a rigid pendulum type physical property tester (device name: RPT-3000W, manufactured by A & D Corporation).
Specifically, 40 μL of ink was dropped on an aluminum substrate, and an ink film with a thickness of 100 μm was applied with a dedicated coating jig (PCT-100) for coating with a thickness of 100 μm. The obtained ink film was installed together with a cold block (CHB-100) within 15 seconds, and a cylinder edge (RBP-040) and a pendulum (FRB-100) were set. In addition, two FRB-100 exclusive weights were set at the bottom of the pendulum. The measurement temperature was raised from normal temperature (25 ° C.) to 60 ° C. at 5 ° C./min, and thereafter kept at 60 ° C. With the time at room temperature (25 ° C.) as the measurement start time, the logarithmic decay rate was plotted against the time every 6 seconds. The obtained plot was smoothed, and the maximum value was calculated as the maximum value of the logarithmic decay rate. The time when the logarithmic decay rate takes the maximum value is the time from the start of measurement until the logarithmic decay rate reaches the maximum value.
The logarithmic decay rate (D ′ (n)) after the smoothing can be obtained as follows when the logarithmic decay rate of the nth plot is defined as D (n).
D ′ (n) = {D (n−2) + D (n−1) + D (n) + D (n + 1) + D (n + 2)} / 5
D ′ (1) = D (1)
D ′ (2) = {D (1) + D (2)} / 2

<Preparation of polyurethane resin particle dispersion 1>
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 1,6-hexanediol and 1,6-hexanedioic acid were adjusted to titanium tetraisopropoxide so that OH / COOH = 1.5. (1,000 ppm (1% by mass) with respect to resin component). Then, it heated up to 200 degreeC in about 4 hours. Next, the temperature was raised to 230 ° C. over 2 hours, and the reaction was continued until there was no effluent water. Then, further, it was made to react under reduced pressure of 1,334 Pa-2,000 Pa (10 mmHg-15 mmHg) for 5 hours, and intermediate polyester was obtained.
Next, the intermediate polyester and isophorone diisocyanate are charged at a molar ratio of 2.0 into a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, and diluted to 48% by mass with ethyl acetate. Then, it was made to react at 100 degreeC for 5 hours. Thereafter, a large amount of water was added and desolubilization was performed to obtain a polyurethane resin particle dispersion 1 having a solid content concentration of 10% by mass.

<Preparation of polyurethane resin particle dispersion 2>
In the preparation of the polyurethane resin particle dispersion 1 described above, the solid content concentration is the same as the preparation of the polyurethane resin particle dispersion 1 except that 1,6-hexanediol is changed to 1,4-butanediol. A polyurethane resin particle dispersion 2 of 10% by mass was obtained.

<Preparation of polyurethane resin particle dispersion 3>
In the preparation of the polyurethane resin particle dispersion 1 described above, 1,6-hexanediol was changed to 1,4-butanediol, and 1,6-hexanedioic acid was changed to 1,4-butanedioic acid. Except for the above, in the same manner as in the preparation of the polyurethane resin particle dispersion 1, a polyurethane resin particle dispersion 3 having a solid content concentration of 10% by mass was obtained.

<Preparation of ink 1>
Copper phthalocyanine pigment (trade name: Pigment Blue 15: 3, manufactured by Dainichi Seika Kogyo Co., Ltd.) 5.0% by mass, tripropylene glycol monobutyl ether (Dow Chemical Japan Co., Ltd.) 4.0% by mass, triethylene glycol Dimethyl ether (manufactured by Dow Chemical Japan Co., Ltd.) 5.0% by mass, 1,2-propanediol (propylene glycol) (manufactured by Kanto Chemical Co., Ltd.) 25.0% by mass, polyurethane resin particle dispersion 1 (solid content concentration: Ink 1 was obtained by adding the remaining amount of ultrapure water so that the total amount was 100.0 mass%) and 50.0 mass%, and the total amount was 100 mass%, followed by stirring and mixing.

<Preparation of inks 2 to 20>
Inks 1 to 21 were obtained in the same manner as the ink 1 except that the composition shown in Tables 1 to 3 below was changed in the preparation of the ink 1.

In addition, in the said Tables 1-3, it is as follows about the brand name of a component, and a manufacturing company name.
Cyan pigment: manufactured by Dainichi Seika Kogyo Co., Ltd., trade name: Pigment Blue 15: 3
-Magenta pigment: manufactured by Dainichi Seika Kogyo Co., Ltd., trade name: Pigment Red 122
-Yellow pigment: manufactured by Dainichi Seika Kogyo Co., Ltd., trade name: Pigment Yellow 154
・ Tripropylene glycol monobutyl ether: Dow Chemical Japan Ltd. ・ Triethylene glycol dimethyl ether: Dow Chemical Japan Ltd. ・ Diethylene glycol ethyl methyl ether: Dow Chemical Japan Ltd. ・ Dipropylene glycol dimethyl ether: Dow Chemical Japan Ltd. -Tripropylene glycol dimethyl ether, manufactured by Dow Chemical Japan Co., Ltd.-1,2-propanediol (propylene glycol): manufactured by Kanto Chemical Co., Ltd.

(Examples 1-35 and Comparative Examples 1-16)
[Image formation]
Using the obtained inks 1 to 21, images were recorded on both sides of a recording medium by an inkjet printing system (RICOH Pro VC60000, manufactured by Ricoh Co., Ltd.), and the images were evaluated. As the recording medium, roll paper of LAG90 (manufactured by Stora Enso, paper width 520.7 mm), Magno Plus Silk (manufactured by Sappi Global), or Magno Gloss (manufactured by Sappi Global) is set as shown in Table 4 below. Then, a solid image was recorded at a resolution of 1,200 dpi. The winding device uses Rewinding module RW6 (manufactured by Hunkeler) to wind up the pressure as shown in Tables 4 and 5 below, and “blocking resistance”, “scratch resistance”, and “gloss” "Sex" was evaluated. Only “blocking resistance” was evaluated after being placed in an environment of a temperature of 40 ° C. and a humidity of 50% for 24 hours. Next, once recording is completed, the paper is set again immediately, the first ink is changed to the second ink (black ink), and a solid image is recorded at a resolution of 1,200 dpi. The “positional shift at the time of applying the second ink” was evaluated. The winding pressure was measured using an apparatus name: I-SCAN5027 (manufactured by Nitta Corporation). The results are shown in Tables 4 and 5 below.

Further, in the LAG90, a contact time of 100 ms measured by a dynamic scanning absorpometer (DSA, Papa Technical Journal, Vol. 48, May 1994, pp. 88 to 92, Kuju Shigenori). The transfer amount of pure water at 2.9 mL / m ² is 2.9 mL / m ² , and the transfer amount of pure water at the contact time of 400 ms is 4.9 mL / m ² .

In the Magno Plus Silk, a contact time of 100 ms as measured by a dynamic scanning absorpometer (DSA, Papa, Japan, 48, May 1994, pp. 88-92, Shigenori Kusaka). The transfer amount of pure water at 2.5 is 2.5 mL / m ² , and the transfer amount of pure water at the contact time of 400 ms is 4.3 mL / m ² .

In the above-mentioned Magno Gloss, contact time measured by a dynamic scanning absorptiometer (DSA, Papa-Pagi Kyodo Journal, Vol. 48, May 1994, pp. 88-92, Shigenori Kusaka) at 100 ms The transfer amount of pure water is 1.8 mL / m ² , and the transfer amount of pure water at the contact time of 400 ms is 3.5 mL / m ² .

(Blocking resistance)
The condition of sticking between recorded images and the state of image transfer (offset) were confirmed by visual observation, and “blocking resistance” was evaluated based on the following evaluation criteria. Rank 7 or higher is good in quality, and rank 10 is particularly good. Moreover, the quality is remarkably deteriorated at rank 3 or lower.
〔Evaluation criteria〕
10: Papers do not stick to each other, and images are not peeled off, resulting in a visually uniform image. 9: Papers do not stick to each other, and there is no image peeling, but there is a minute image dropout of less than 10 μm. 8: Paper does not stick to each other and image peeling does not occur, but there is a minute image dropout of 10 μm or more and less than 20 μm 7: Paper does not stick to each other and image peeling does not occur, but there is a minute image dropout of 20 μm or more to less than 30 μm 3: Papers are sticking to each other, and the image is extremely chipped 1: Papers are sticking to each other, images are extremely chipped, and paper is also severely lost 0: Papers are sticking to each other, they are united

(Rubbing resistance)
About each obtained image, the image was rubbed 20 times using the paper (LAG90 (made by Stora Enso)) cut into a 1.2 cm square, and the reflection type color spectrophotometric densitometer (made by X-Rite) was used. Then, the ink adhesion stain on the paper was measured, the density obtained by subtracting the background color of the rubbed paper was calculated, and the “rubbing resistance” was evaluated based on the following evaluation criteria. The allowable ranges are A and B.
〔Evaluation criteria〕
A: Transfer density is less than 0.05 B: Transfer density is 0.05 or more and less than 0.10 C: Transfer density is 0.10 or more

(Glossy)
About each obtained image, 60 degree glossiness was measured using the gloss meter (the BYK Gardner company make: Micro-TRI-Gloss 4520), and "glossiness" before and after pressurization was evaluated. When image transfer (offset) occurred, no value was measured ("-" in Table 4) because measurement was impossible.

(Position misalignment during second ink application)
The positional deviation from the first ink when the second ink was recorded was visually confirmed, and the “positional deviation at the time of applying the second ink” was evaluated based on the following evaluation criteria. The allowable range is A.
〔Evaluation criteria〕
A: No misalignment B: Misalignment

(Light resistance)
About the obtained image, the xenon irradiance of the outdoor sunlight approximated to 0 in an environment of 70 ° C., 50% RH, and black panel temperature 89 ° C. using an accelerated weathering tester (Atlas Co., Ltd .: Weatherometer Ci35AW). Irradiation was performed at 35 W / m ² (340 nm) for 24 hours, and fading and color change before and after irradiation were determined according to the following evaluation criteria. The allowable range is A.
〔Evaluation criteria〕
A: Almost no change B: Fading, large color change

Japanese Patent No. 5445220

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Recording medium 3 Paper supply means 4 Ink application means (1st ink application means)
5 Pressurizing means

Claims (11)

First ink applying means for forming an image by applying a first ink to a recording medium;
Pressurizing means for applying pressure to the image,
The first ink contains water, an organic solvent, and a copper phthalocyanine pigment,
The first ink takes a maximum value when a logarithmic decay rate is 7200 seconds or less when an ink film formed using the first ink is measured by a rigid pendulum test at 60 ° C. The value is 0.300 or less,
The image forming apparatus, wherein the pressure is 3.5 kg / cm ² or more and 16.0 kg / cm ² or less. The recording medium is continuous paper;
The image forming apparatus according to claim 1, wherein the pressurizing unit is a unit that applies the pressure to the image by winding the continuous paper on which the image is formed in a roll shape.   The image forming apparatus according to claim 2, further comprising a second ink applying unit configured to apply a second ink to the continuous paper to which the pressure is applied to form an image. The recording medium has a support and a coating layer provided on at least one side of the support, and the recording medium of pure water at a contact time of 100 ms measured with a dynamic scanning absorptiometer a transfer amount is 2~35ml / ^{m 2} to, and the image according to any one of claims 1 to 3 transfer amount to the recording medium of the pure water is 3~40ml / ^{m 2} at a contact time 400ms Forming equipment. The recording medium is continuous paper;
The pressurizing means is means for generating the pressure by winding the continuous paper on which the image is formed in a roll shape,
The recording medium has a support and a coating layer provided on at least one side of the support, and the recording medium of pure water at a contact time of 100 ms measured with a dynamic scanning absorptiometer ^2. The image forming apparatus according to claim 1, wherein a transfer amount to the recording medium is ² to 35 ml / m ² and a transfer amount of pure water to the recording medium at a contact time of 400 ms is 3 to 40 ml / m ² .   The image forming apparatus according to claim 1, wherein the first ink contains urethane resin particles.   The image forming apparatus according to claim 6, wherein the organic solvent includes an ether compound having no hydroxyl group. The image forming apparatus according to claim 7, wherein the ether compound is represented by the following general formula (1).

However, the general formula (1), ^{R 1} is a hydrogen atom, or represents a number from 1 to 10 alkyl group carbon, ^{R 2} and ^{R 3} are each independently 1 to 10 alkyl group carbon atoms N represents an integer of 1 to 5.   The mass ratio (ether compound / urethane resin particles) between the content (mass%) of the urethane resin particles relative to the total amount of the first ink and the content (mass%) of the ether compound relative to the total amount of the first ink. The image forming apparatus according to claim 7, wherein the image forming apparatus is 0.40 or more and 1.60 or less.   The image forming apparatus according to claim 7, wherein a content of the ether compound with respect to a total amount of the first ink is 2.0% by mass or more and 8.0% by mass or less. A first ink application step of forming an image by applying a first ink to a recording medium;
A pressurizing step of applying pressure to the image,
The first ink contains water, an organic solvent, and a copper phthalocyanine pigment,
The first ink takes a maximum value when a logarithmic decay rate is 7200 seconds or less when an ink film formed using the first ink is measured by a rigid pendulum test at 60 ° C. The value is 0.300 or less,
The image forming method, wherein the pressure is 3.5 kg / cm ² or more and 16.0 kg / cm ² or less.

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