JP2022002900A - Image forming apparatus, image forming method and ink - Google Patents

Abstract

To provide an image forming apparatus capable of obtaining an image excellent in blocking resistance and rubbing resistance and high in glossiness even when applying pressure to an image.SOLUTION: An image forming apparatus includes first ink applying means for applying a first ink to a recording medium to form an image and pressure means for applying pressure to the image. The first ink includes water, an organic solvent and copper phthalocyanine pigment; when measuring an ink film formed by using the first ink on a condition of 60°C by a rigid body pendulum test, the logarithmic decrement of the first ink has the maximum of 0.300 or less at 7200 seconds or less; and the pressure is 3.5 kg/cm2 or more and 16.0 kg/cm2 or less.SELECTED DRAWING: None

Description

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

The inkjet recording method not only has the advantages of low noise of the equipment used and good operability, but also has the advantages of being easy to colorize and being able to use plain paper as a recording medium. It is widely used as an output device in offices and homes.

On the other hand, even in industrial applications, it is expected that it will be used as an output machine for digital printing due to the improvement of inkjet technology, and printing machines capable of recording on non-absorbable recording media using solvent ink or UV ink have been put on the market. rice field. However, in recent years, the demand for water-based inks has been increasing due to environmental friendliness.

As water-based inks for inkjet, inks whose printing target is special paper such as plain paper or photographic glossy paper have been developed for a long time. On the other hand, in recent years, the use of the inkjet recording method is expected to expand, 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.

Further, in industrial applications, roll paper-compatible printers that use roll paper as a printing medium are being developed. For example, the displacement amount of the movable member is controlled with good responsiveness to effectively prevent the movable member from being displaced beyond the movable range, and the movable member is damaged, vibrated, or makes an abnormal noise due to collision with the inner surface of the housing of the device. A roll paper transporting device has been proposed that can avoid problems such as the occurrence of paper and the adhesion of stains on paper (see Patent Document 1).

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

The image forming apparatus of the present invention, which solves the above-mentioned problems, has a first ink applying means for applying the first ink to a recording medium to form an image, and a pressurizing means for applying pressure to the image. The first ink contains water, an organic solvent, and a copper phthalocyanine pigment, and the first ink is an ink film formed by using the first ink under a rigid pendulum test at 60 ° C. When the logarithmic decay rate measured in 1 is 7200 seconds or less, the maximum value is taken 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. ^{It is 2} or less.

According to the present invention, it is possible to provide an image forming apparatus which is excellent in blocking resistance and rubbing resistance and can obtain an image having high glossiness.

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

<Image forming device and image forming method>
Hereinafter, embodiments of the present invention will be described.
An image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.
The image forming apparatus 1 shown in FIG. 1 is an apparatus for forming an image on the recording medium 2 by applying ink to the recording medium 2. The image forming apparatus 1 includes a paper feeding means 3, an ink applying means (first ink applying means) 4, and a winding means 5.

The paper feeding means 3 is a means for feeding the recording medium 2 to a position where the ink applying means 4 applies ink.

The ink applying means 4 is a means for applying ink to the fed recording medium 2 to form an image. As the ink applying means 4, a means for applying the ink by an inkjet recording method is preferable. In the case of the means for applying by the inkjet recording method, it is preferable to have four ejection heads corresponding to black (K), cyan (C), magenta (M) and yellow (Y). Ink is applied by 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, a spray coating method, etc., in addition to the inkjet recording method. Means to do. The ink applying step as one step of the image forming method can be suitably carried out by the ink applying means. The details of the ink will be described later.

The winding means 5 is arranged at a position facing the paper feeding means 3, and is a means for winding the recording medium 2 fed from the paper feeding means 3. In the example shown in FIG. 1, continuous paper is used as the recording medium 2. The continuous paper is a recording medium that is continuous in the transport direction at the time of image formation and is longer than the length of the print unit (1 page) in the transport direction. As the continuous paper, for example, roll paper rolled into a roll shape can be used. In the example shown in FIG. 1, the recording medium 2 rolled into a roll shape is set in the paper feeding means 3. Then, by winding the recording medium 2 fed from the paper feeding means 3 using the winding means 5, the recording medium 2 is conveyed in the conveying direction (direction indicated by the arrow in FIG. 1).

In the image forming apparatus shown in FIG. 1, the winding means 5 also functions as a pressurizing means for applying pressure to the image formed on the recording medium 2. That is, the winding means 5 winds up the recording medium 2 after the image is formed in a roll shape, and in the process of winding the recording medium 2 in a roll shape, pressure is applied to the recording medium 2. In particular, in the vicinity of the rotation axis of the winding means 5, a large pressure is applied due to the weight of the recording medium 2.

Further, as shown in FIG. 1, when the winding means 5 winds up the recording medium 2 fed from the paper feeding means 3, the recording medium 2 is tensioned to record on the outer edge of the winding means 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 rotation speeds of the paper feeding means 3 and the winding means 5, respectively.
In the example shown in FIG. 1, a case where roll paper is used as a recording medium is shown, but 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, as a recording medium, a continuous paper folded at predetermined intervals, a continuous form in which cutable perforations are formed at predetermined intervals, or the like is wound in a roll shape. No continuous paper may be used.
As described above, when a recording medium other than roll paper is used, it is not necessary to wind 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 and continuous form is used as a recording medium, the recording medium after image formation can be bent and laminated along creases and perforations. In this case, pressure is applied to the image due to the weight of the stacked recording media. In this way, when pressure is applied to the image due to its own weight, the position where the own weight is generated in the image forming apparatus is defined as the pressurizing means. For example, if continuous paper is laminated in the discharge section where the recording medium is discharged and pressure is applied to the image by its own weight, the discharge section corresponds to a pressurizing means.

Further, 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. The cut paper is an independent recording medium for each print unit (1 page) in the transport direction at the time of image formation. Even when the cut paper is used, pressure can be applied to the image formed on the recording medium by laminating the recording medium (cut paper) after the image formation.

In the image forming apparatus according to the present embodiment, a pressurizing means for applying pressure to the image formed on the recording medium may be separately provided. For example, by providing rollers on the upper surface side and the lower surface side of the recording medium and transporting the recording medium after image formation by using these rollers, pressure can be applied to the image formed on the recording medium. ..

Further, the image forming apparatus 1 winds up the recording medium 2 after image formation by the winding means 5, and then applies ink (second ink) to the wound recording medium 2 again. It may be configured to perform "reprinting".

When performing additional printing, the recording medium wound by the winding means 5 may be set again in the paper feeding means 3 to form an image. At this time, the ink applying means for performing additional printing may be the same as the ink applying means 4 shown in FIG. 1 (in this case, the ink applying means 4 becomes the second ink applying means), or a separate ink applying means (first). Second ink applying means) may be provided.
The image forming apparatus 1 is not limited to the above means, and may include other means as needed.

Further, the means such as the ink applying means 4 and the winding means 5 are not limited to the case where each means is provided in the image forming apparatus 1 which is a single device, and for example, the ink applying means 4 and the winding means 5 are used. Each means may be configured to be distributed or straddled in separate devices.

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

Images formed with conventional ink have poor blocking resistance, and the image is offset when pressure is applied (the problem that the image peels off from the recording medium), the problem is poor scratch resistance, and the image has high gloss. There was a problem that I could not get. The image forming apparatus of the present invention is based on the knowledge regarding the above problem.
The blocking resistance and the rubbing resistance, which are the subjects of the present invention, are related to the fixing property between the image and the recording medium. As an example, the fixability can be improved by adding resin particles to the conventional ink, but the resin capable of improving the fixability has high viscoelasticity, and the addition of the above resin causes logarithmic attenuation. The maximum value of the rate becomes large.

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

When an ink with a large maximum logarithmic decrement is used, the viscoelasticity of the ink is high. The problem is that the image is offset at such timing. Further, by applying sufficient pressure to the image, the surface of the image can be smoothed to obtain a highly glossy image, and the rubbing resistance can be improved, but the image should be avoided from being offset. Then, it is not possible to apply sufficient pressure, and it is also a problem that an image with high gloss cannot be obtained.

Further, when an image forming apparatus using continuous paper is used, a large pressure is applied to the image near the rotation axis of the roll in the process of rewinding the continuous paper after image formation into a roll shape, and the image is offset. Is a problem. Furthermore, when tension is applied to continuous paper to rewind the paper after image formation into a roll, a large pressure is applied not only near the axis of rotation of the roll but also at the outer edge of the roll, causing the image to be offset. It becomes.

Further, in the case of performing the above-mentioned additional printing, if the winding pressure after the first image formation by the first ink applying means is large, the roll is wound uniformly and the additional printing can be performed accurately. As you can see, the image is offset. On the other hand, if the take-up pressure is small, the roll bends and becomes a non-uniform state, and there is a problem of misalignment of recording due to the paper not being conveyed at a constant speed during reprinting. When the second ink applying means forms an image on the same surface as the image formed by the first ink applying means at the time of reprinting, it is compared with the case where the image is formed on the opposite surface. The problem caused by misalignment increases. This is because the former may cause a positional deviation from the image formed by the first ink applying means in addition to the positional deviation that may occur in the image formation by the second ink applying means. However, the second ink applying means in the present invention does not exclude the 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.

[Logarithmic decrement]
Next, the logarithmic decrement 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 decrement rate is 7200 seconds or less when the ink film formed using the ink is measured by a rigid pendulum test under the condition of 60 ° C. Moreover, it has the property that the maximum value is 0.300 or less.

In particular, in the invention according to the present embodiment, the maximum value of the logarithmic decrement is more preferably 0.055 or more and 0.293 or less, and further preferably 0.055 or more and 0.117 or less. The time for the logarithmic decrement of the ink film to reach 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.
When the maximum value of the logarithmic decrement is 0.300 or less, the stickiness of the image formed by using the ink is suppressed, and the occurrence of blocking can be suppressed.

Further, when the time for the logarithmic decrement to reach the maximum value is 7,200 seconds or less, the time for maximizing the stickiness of the image formed by using the ink can be shortened. If the time for maximizing stickiness can be increased, pressure can be applied to the image by a pressurizing means after the stickiness is sufficiently reduced. Therefore, for example, when a pressurizing means is provided immediately after the first ink applying means, or an image forming apparatus which is a high-speed printing machine having a short transfer time between the first ink applying means and the pressurizing means. The occurrence of blocking can be suppressed even when the above is used. The time at which the logarithmic decrement reaches the maximum value means the time from the start of measurement until the logarithmic decrement 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 decrement is 0.300 or less and the time for the maximum logarithmic decrement is 7,200 seconds or less is used. Since it is used, ^{blocking does not occur even if a pressure of 3.5 kg / cm 2} or more and 16.0 kg / cm ² or less is applied after image formation, and an image having good abrasion resistance and gloss can be obtained. Further, since the stickiness of the image is less likely to increase in the image formed by using the ink having such a property, the image does not stick to the contact member such as the backing paper or the roller, and the occurrence of blocking can be suppressed. .. Further, since blocking does not occur, it is possible to strongly wind the papers together, thereby improving the fixability and the rubbing resistance. Further, by strongly winding the papers together, the surface is smoothed and the glossiness can be improved.

Next, a specific method for measuring the logarithmic decrement will be described.
In the method for measuring the logarithmic decrement, a rigid pendulum type physical property tester (device name: RPT-3000W, manufactured by A & D Co., Ltd.) is used. 40 μL of ink is dropped on the aluminum substrate, and an ink film having a thickness of 100 μm is applied with a special coating jig (PCT-100) for coating with a thickness of 100 μm. The obtained ink film is installed together with the cooling 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 normal temperature (25 ° C.) to 60 ° C. at 5 ° C./min, and thereafter the temperature is kept at 60 ° C. The logarithmic decrement is plotted every 6 seconds with the time point at room temperature (25 ° C.) as the measurement start time. The obtained plot is smoothed, the maximum value is calculated, and the maximum value of the logarithmic decrement is used. The maximum value of the logarithmic decrement can be used as an index of tack force (stickiness).
The logarithmic decrement (D'(n)) after smoothing can be obtained as follows when the logarithmic decrement 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 decrement and the elapsed time. As shown in FIG. 2, in Sample A, the maximum value of the logarithmic decrement exceeds 0.300. On the other hand, in SampleB, the maximum value of the logarithmic decrement is 0.300 or less, and the time for reaching the maximum value of the logarithmic decrement is 7,200 seconds or less. Like SampleB, the maximum value of the logarithmic decrement is 0.300 or less, and the time to take the maximum logarithmic decrement is 7,200 seconds or less, so that the blocking resistance, the rubbing resistance, and the glossiness Can be improved.
[Pressure applied to the image by the pressurizing means and pressurizing process]

The pressure applied to the image by the pressurizing means is 3.5 kg / cm ² or more and 16.0 kg / cm ² or less, and 3.5 kg / cm ² or more and 5.8 kg / cm ² or less is preferable. 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, ^{and when the pressure is 16.0 kg / cm 2} or less, the image is a pressure roller or the like. It is possible to prevent the blocking resistance from deteriorating by offsetting the overlapping images and paper. The pressure measuring method is not particularly limited, and a known device can be appropriately selected according to the purpose. Further, even when the pressure applied to the image by the pressurizing means is generated by winding the continuous paper after applying the ink in a roll shape, there is no particular limitation on the pressure measuring method, and it is appropriately known according to the purpose. You can select the device. For example, device name: I-SCAN5027 (manufactured by Nitta Corporation) can be used.

The pressure in the roll-shaped continuous paper can be calculated, for example, from photographs and information of the rolled continuous paper with reference to the diameter, height, and mass of the roll-shaped continuous paper.

When the recording medium is continuous paper, the pressure applied to the image by the pressurizing means is preferably generated by winding the continuous paper after applying the ink in a roll shape (see FIG. 1). Further, if even one of the above pressures is applied to a plurality of images on continuous paper, the present invention is applicable.

An image in which the maximum value of the logarithmic decrement and the time to reach the maximum value are within a predetermined range does not cause an offset when a pressure within the predetermined pressure range is applied, and not only the blocking resistance is good. , The scratch resistance and glossiness of the image can also be improved. Further, since a sufficient winding pressure is applied within the above pressure range, it is possible to obtain an additional effect that reprinting can be performed without any problem.

The maximum value of the logarithmic decrement of the ink film and the time during which the logarithmic decrement is at the maximum are particularly affected by the resin, organic solvent, and the like in the ink. The types of resins, organic solvents, etc., the amount of addition, and the like as examples that can realize the maximum value of the logarithmic decrement and the time range in which the logarithmic decrement takes the maximum value will be described in detail below.

<First ink>
Hereinafter, the organic solvent, water, coloring material, resin, additives and the like used for the first ink will be described. In addition, when only "ink" is described in this specification, it means "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-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, 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 Polyhydric alcohol alkyl ethers such as ethers, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone. , 1,3-Dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and other nitrogen-containing heterocyclic compounds, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N- Amidos such as dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate and ethylene carbonate. And so on.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because it not only functions as a wetting agent but also has good drying properties.

Polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
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, and tripropylene glycol monobutyl ether. Polyhydric alcohol alkyl ethers such as, etc .; Examples thereof include 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 the permeability of ink 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, but preferably contains an ether compound having no hydroxyl group, and the hydroxyl group represented by the following general formula (1) is preferable. It is more preferable to contain an ether compound that does not exist.

However, in the general formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 or more and 10 or less carbon atoms, and R ² and R ³ independently represent an alkyl having 1 or more and 10 or less carbon atoms. It represents a group, and n represents an integer of 1 or more and 5 or less.
^{The R 1} in the general formula (1) is a hydrogen atom, an alkyl group having 1 or more carbon atoms and 10 or less carbon atoms, and a hydrogen atom and a methyl group are preferable.
^{The R 2} in the general formula (1) is an alkyl group having 1 or more carbon atoms and 10 or less carbon atoms, and a methyl group and an ethyl group are preferable.
^{The R 3} in the general formula (1) is an alkyl group having 1 or more carbon atoms and 10 or less carbon atoms, and a methyl group, an ethyl group or a butyl group is preferable.
The n in the general formula (1) is an integer of 1 or more and 5 or less, and an integer of 2 or more and 3 or less is preferable.

The ether compound represented by the general formula (1) is not particularly limited and may be appropriately selected depending on the intended purpose, but triethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether and 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 may be appropriately selected depending on the intended 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. More preferably, it is 20% by mass or more and 60% by mass or less.

<Resin>
The type of resin contained in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, etc. Examples thereof include resins, styrene-butadiene resins, vinyl chloride resins, styrene acrylic resins, acrylic silicone resins, polyrotaxane resins and the like.

Resin particles made of these resins may be used. It is possible to obtain ink by mixing resin particles 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. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more kinds of resin particles. From the viewpoint of obtaining a uniform image, it is preferable to use the styrene acrylic resin alone, the urethane resin alone, or a combination of the urethane resin and the 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 an isocyanate compound having a plurality of isocyanate groups and a polyol compound having a plurality of hydroxyl groups. The isocyanate compound and the polyol compound may be polymer compounds themselves.

--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 alone or in combination of two or more.

Examples of the bifunctional isocyanate compound include isophorodiisocyanate, cyclohexanediisocyanate, 1,6-hexanediisocyanate, 1,4-butane diisocyanate, 1,4-benzenediisocyanate, and diphenylmethane diisocyanate.

Examples of the trifunctional isocyanate compound include 1,3,5-cyclohexanetriisocyanate, 1,4,8-octanetriisocyanate, and 1,3,5-benzenetriisocyanate.

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

Among these, although there are differences in the mechanical strength and weather resistance obtained by synthesizing urethane using these, isophorodiisocyanate and cyclohexanediisocyanate are preferable from the viewpoint of mass production handling, environmental protection, and physical property manipulation.

--Polyol compound ---
The polyol compound is not particularly limited and may be appropriately selected depending on the intended purpose. For example, alkylene glycols (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol) , 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diol (1,4-cyclohexanedimethanol, etc.) , Hydrogenated bisphenol A, etc.); Bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the alicyclic diol; 4,4'-dihydroxy Biphenyls (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) ether, 2,2-bis (3-fluoro-4-hydroxyphenyl) propane, 2,2-bis (3,5-difluoro-4-hydroxyphenyl) propane (also known as: Tetrafluorobisphenol A), 2,2-bis (3-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane); bis (4-hydroxyphenyl) ethers (bis (3-fluoro) -4-Hydroxyphenyl) ether and the like); Examples thereof include alkylene oxide (ethylene oxide, propylene oxide, butylene oxide and the like) adducts of the bisphenols. These may be used alone or in combination of two or more.

In addition, examples of the polyol compound include carbonate-based polyols, ester-based polyols, and ether-based polyols. These may be used alone or in combination of two or more. Each of these has two or more hydroxyl groups in the polyol compound.
It is synthetically preferable that the polyol compound has hydroxyl groups at both ends of the compound.

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

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

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

However, in the general formulas (A) to (C), R independently contains various skeletons such as a hexamethylene group, a cyclohexane group, a phenylene group, a tetramethylene group, a cyclohexanedimethylene group, and a cyclohexanemonomethylene group. This is not limited to the ones given in the example. Further, n is 1 to 20.

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

The content of the resin is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of fixability and storage stability of the ink, 1% by mass or more and 30% by mass or less with respect to the total amount of the ink. Is preferable, and 5% by mass or more and 20% by mass or less is 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, but from the viewpoint of improving image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number of inks. 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 Microtrac Bell Co., Ltd.).

[Mass ratio (ether compound / urethane resin particles)]
The mass ratio (ether compound / urethane resin particles) of the content (mass%) of the urethane resin particles to the content (mass%) of the ether compound having no hydroxyl group is 0.40 or more and 1.60. The following is preferable, 0.60 or more and 1.40 or less are more preferable, and 0.80 or more and 1.20 or less are particularly preferable. 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 decrement is 0.300 or less and the time for reaching the maximum value of the logarithmic decrement is 7. , It becomes easy to set it to 200 seconds or less.

<Copper phthalocyanine pigment>
A copper phthalocyanine pigment can be used as the coloring material.
Phthalocyanine pigments are planar molecules, and it is easy to take molecular crystals. In order to take a molecular crystal, a force that removes the solvent from the molecules works and it is pushed out of the crystal. By extruding the solvent onto a surface that dries easily, the dryness is improved and the logarithmic decrement is less likely to increase.

As the copper phthalocyanine pigment, one type may be used alone, or two or more types may be used in combination. Further, a mixed crystal may be used.

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

As a copper phthalocyanine pigment, for example, C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, C.I. I. Pigment Greens 7, 36 and the like.

As a specific example of the above complementary color pigment, for black, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, etc., 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, 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 Calcium 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 Greens 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 viewpoint of improving the image density, good fixing property and ejection stability. % Or less.

To disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing it, a method of dispersing using a dispersant, And so on.

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

As a method of coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is encapsulated in microcapsules and can be dispersed in water can be used. This can be rephrased as a resin-coated pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effect of the present invention is not impaired. May be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant represented by a surfactant.

As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and Naphthalene sulfonic acid Na formalin condensate can also be suitably used as a dispersant.
The dispersant may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain an ink by mixing a material such as water or an organic solvent with a pigment. It is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
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. It is good to use a disperser for dispersion.
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 the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac 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, good ejection stability can be obtained and the image density is increased by 0.1 mass. % Or more and 50% by mass or less are preferable, and 0.1% by mass or more and 30% by mass or less are more preferable.
It is preferable that the pigment dispersion is degassed by filtering coarse particles with a filter, a centrifuge, or the like, if necessary.

<Water>
The content of water in the 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 ink, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass. % To 60% by mass is more preferable.

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

<Surfactant>
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, side chain double-ended modified polydimethylsiloxane, and the like. Those having an oxyethylene group and a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the Si portion side chain of dimethylsiloxane.
Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because they have low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes 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. The counter ions of the salts in these fluorine-based surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , and NH (CH ₂ CH ₂ OH). ₃ etc. can be mentioned.
Examples of the amphoteric tenside include laurylaminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include a fatty acid ester and an ethylene oxide adduct of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, polyoxyethylene alkyl ether sulfate salt and the like.
These may be used alone or in combination of two or more.

（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-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain-modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, one-ended modified polydimethylsiloxane, side. Examples thereof include polydimethylsiloxane modified at both ends of the chain, and a polyether-modified silicone-based surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibits good properties as an aqueous surfactant, and is particularly effective. preferable.
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. As commercially available products, for example, they can be obtained from Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.
The above-mentioned polyether-modified silicone-based 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) may be dimethylpoly. Examples thereof include those introduced into the Si part side chain of siloxane.

(However, 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.)
Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant, for example, KF-618, KF-642, KF-643 (Shinetsu Chemical Industry Co., Ltd.), EMALEX-SS-5602, SS-. 1906EX (Nippon 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 (Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) and the like can be mentioned.

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 compound having 2 to 16 carbon atoms substituted with fluorine is preferable, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferable.
Examples of the fluorosurfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Among these, the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because it has less foaming property, and is particularly a fluorine-based compound represented by the general formula (F-1) and the general formula (F-2). Surfactants are preferred.

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 above general formula (F-2), Y is H or CmF _{2m + 1} and m is an integer of 1 to 6, or CH ₂ CH (OH) CH _2- CmF _{2m + 1} and m is 4 to 6. It is an integer, or CpH _{2p + 1} and p is an integer of 1-19. n is an integer of 1 to 6. a is an integer of 4 to 14.
Commercially available products may be used as the above-mentioned fluorine-based surfactant. Examples of this commercially available product include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Full Lard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafuck F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.); 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 The Chemours Company); 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 (manufactured by Omniova), Unidyne DSN-403N (manufactured by Daikin Industries Co., Ltd.) Among these, the FS-3100, FS-34, and FS- 300, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omninova, and Unidyne DSN-manufactured by Daikin Industries Co., Ltd. 403N is particularly preferable.

The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of excellent wettability and ejection stability and improvement in image quality, 0.001 mass is used. % Or more and 5% by mass or less are preferable, and 0.05% by mass or more and 5% by mass or less are more preferable.

<Defoamer>
The defoaming agent is not particularly limited, and examples thereof include silicone-based defoaming agents, polyether-based defoaming agents, and fatty acid ester-based defoaming agents. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because it has an excellent defoaming effect.

<Preservatives and fungicides>
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one and the like.

<Rust inhibitor>
The rust preventive is not particularly limited, and examples thereof include acidic sulfite and sodium thiosulfate.

<pH adjuster>
The pH adjusting agent 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.

The physical characteristics of the ink are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. 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 print density and character quality and obtaining good ejection properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. As the measurement conditions, it is possible to measure at 25 ° C. with a standard cone rotor (1 ° 34'× R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 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 preferably 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 that comes into contact with the liquid.

<Second ink>
Hereinafter, the organic solvent, water, coloring material, resin, additives 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-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, 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 Polyhydric alcohol alkyl ethers such as ethers, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone. , 1,3-Dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and other nitrogen-containing heterocyclic compounds, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N- Amidos such as dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate and ethylene carbonate. And so on.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because it not only functions as a wetting agent but also has good drying properties.

Polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of the glycol ether compound 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. Ethers; Examples thereof 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 the 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, 10% by mass or more is 60. It is preferably 20% by mass or less, more preferably 20% by mass or more and 60% by mass or less.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Further, 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 color pigment such as gold or silver, a metallic pigment, or the like can be used.
As inorganic pigments, 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, and chrome yellow. Can be used.
Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , Dye chelate (for example, basic dye type chelate, acid dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like can be used. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
As a specific example of the pigment, for black, 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, 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 Calcium 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 Greens 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.
As the dye, for example, 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. Dilekdo 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, 35 can be mentioned.

The content of the coloring 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 viewpoint of improving the image density, good fixing property and ejection stability. It is 10% by mass or less.

In order to disperse the pigment to obtain a second ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersible pigment, a method of coating the surface of the pigment with a resin and dispersing it, and a dispersant are used. And how to disperse.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) so that the pigment can be dispersed in water. Can be mentioned.
Examples of the method of coating the surface of the pigment with a resin and dispersing the pigment include a method of encapsulating the pigment in microcapsules so that the pigment can be dispersed in water. This can be rephrased as a resin-coated pigment. In this case, all the pigments to be blended in the second ink do not need to be coated with the resin, and the uncoated pigment or the partially coated pigment is used as long as the effect of the present invention is not impaired. It may be dispersed in the ink of.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and Naphthalene sulfonic acid Na formalin condensate can also be suitably used as a dispersant.
The dispersant may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain a second ink by mixing a material such as water or an organic solvent with the pigment. Further, it is also possible to produce a second ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
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. It is good to use a disperser for dispersion.
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 the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac 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, good ejection stability can be obtained and the image density is increased by 0.1 mass. % Or more and 50% by mass or less are preferable, and 0.1% by mass or more and 30% by mass or less are more preferable.
It is preferable that the pigment dispersion is degassed by filtering coarse particles with a filter, a centrifuge, or the like, if necessary.

<Resin>
The type of resin contained in the second ink is not particularly limited and may be appropriately selected depending on the intended purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin. , Butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, acrylic silicone resin and the like.
Resin particles made of these resins may be used. It is possible to obtain a second ink by mixing the resin particles 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. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more kinds of resin particles.

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

The content of the resin is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of fixability and storage stability of the second ink, 1 mass with respect to the total amount of the second ink. % Or more and 30% by mass or less are preferable, and 5% by mass or more and 20% by mass or less are 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, but is converted into the maximum number from the viewpoint of improving image quality such as ejection stability and image density. 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 Microtrac 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, transparency sheet, and general-purpose printing paper.

In particular, the recording medium to which the effect can be obtained in the present invention includes a support, a coating layer provided on at least one surface side of the support, and further has another layer as needed. A recording medium or the like can be mentioned.

The recording medium having the support and the coating layer is generally called coated paper, and is known as a recording medium having low ink permeability. It is difficult to firmly fix the coloring material on a recording medium with low permeability such as coated paper, and blocking resistance and rubbing resistance are often deteriorated. However, as described above, the ink film is a rigid pendulum. If the maximum value of the logarithmic decrement at 60 ° C. measured by the test is 0.300 or less and the time to reach the maximum value of the logarithmic decrement is 7,200 seconds or less, 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 amount of pure water transferred to the recording medium at a contact time of 100 ms measured by a dynamic scanning liquid absorbent meter is 2 mL / m ² or more and 35 mL / m ² or less. Is preferable, and 2 mL / m ² or more and 10 mL / m ² or less is more preferable.

If the transfer amount of the ink and pure water at the contact time of 100 ms is too small, beading may easily occur, and if it is too large, the ink dot diameter after image formation becomes too small 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.

If the amount of transfer at the contact time of 400 ms is small, the drying property is insufficient, so that spur marks may easily occur, and if it is too large, the gloss of the image portion after drying tends to be low. be. The amount of pure water transferred to the recording medium at the contact times of 100 ms and 400 ms can be measured on the surface of the recording medium on the side having the coating layer.

Here, the dynamic scanning absorber (DSA, Paper Technology Cooperative Magazine, Vol. 48, May 1994, pp. 88-92, Shigenori Kukan) absorbs liquid in an extremely short time. It is a device that can measure the amount accurately. The dynamic scanning liquid absorber reads the speed of liquid absorption directly from the movement of the meniscus in the capillary, makes the sample disk-shaped, and scans the liquid-absorbing head spirally on the sample, and scans the speed according to a preset pattern. Is automatically changed, and the measurement is performed by the method of measuring the required number of points with one sample.

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

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 values of the transfer amounts at the contact times in the vicinity of each contact time.
-Support-

The support is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paper mainly composed of wood fibers, sheet-like substances such as non-woven fabric mainly composed of wood fibers and synthetic fibers, and the like. ..
The paper is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, wood pulp, used paper pulp and the like are used.

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

The raw materials for the recycled paper pulp are fine white, ruled white, cream white, card, special white, medium white, imitation, fair white, Kent, and white, which are shown in the recycled paper standard quality standard table of the Recycled Paper Recycling Promotion Center. Examples include art, special cuts, special cuts, newspapers, and magazines.

Specifically, information-related paper such as non-coated computer paper, heat-sensitive paper, pressure-sensitive paper, and other printer paper; OA waste paper such as PPC paper; art paper, coated paper, finely coated paper, matte paper, and the like. Paper; high-quality paper, high-quality color, notebook, notepaper, wrapping paper, fancy paper, medium-quality paper, newspaper paper, stencil paper, super hanging paper, imitation paper, pure white roll paper, uncoated paper such as milk carton, etc. Used paper and paperboard, such as chemical pulp paper and high-yield pulp-containing paper.
These may be used alone or in combination of two or more.
The recycled paper pulp can generally be produced from a combination of the following four steps.
(1) To dissociate, the used paper is treated with a pulper with mechanical force and chemicals to loosen it into fibers, and the printing ink is peeled from the fibers.
(2) For dust removal, foreign matter (plastic, etc.) and dust contained in used paper are removed with a screen, cleaner, or the like.
(3) For 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 enhances the whiteness of fibers by using an oxidizing action or a reducing action.
When the used paper pulp is mixed, the mixing ratio of the used paper pulp in the total pulp is preferably 40% or less from the viewpoint of curl countermeasures after image formation.
As the internal filler used for the support, for example, a conventionally known pigment as a white pigment is used.

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, and silica soil. White inorganic pigments such as calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, rithopone, zeolite, magnesium carbonate, magnesium hydroxide, etc .; styrene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins , Organic pigments such as melamine resin, and the like. These may be used alone or in combination of two or more.

Examples of the internal sizing agent used when making the support include a neutral rosin-based sizing agent used for neutral paper making, alkenyl succinic anhydride (ASA), alkyl ketene dimer (AKD), and petroleum resin. Examples include system size agents. Of these, neutral rosin sizing agents or alkenyl succinic anhydride are particularly suitable. The alkyl ketene dimer can be added in a small amount because of its high size effect, but it is not preferable from the viewpoint of transportability during inkjet recording because the friction coefficient on the surface of the recording paper (recording medium) is lowered and it becomes slippery. In some cases.

-Coating layer-
The coating layer contains a pigment and a binder (binder), and further contains a surfactant and other components, if necessary. In the present invention, the coating layer may contain a pigment and a binder (binder) as described above, and it does not matter whether the coating layer is actually coated or not. 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, and the like. Examples include zinc hydroxide and chlorite. Among these, kaolin is particularly preferable because it has excellent glossiness and can have a texture similar to that of paper for offset printing.

The kaolin includes delaminated kaolin, calcined kaolin, engineered kaolin by surface modification, etc., but in consideration of gloss development, a particle size distribution with a particle size of 2 μm or less is 80% by mass or more. It is preferable that the kaolin contained in the kaolin accounts for 50% by mass or more of the total kaolin.

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

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 amount of the organic pigment added 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 development and its specific gravity is smaller than that of the inorganic pigment, it is possible to obtain a coating layer having a bulky, high gloss and good surface coating property. When the content is 2 parts by mass or more, the effect can be improved, and when it 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. be.

The organic pigment includes a dense type, a hollow type, a donut type and the like in its form, but in consideration of the balance between gloss development, surface coating property and fluidity of the coating liquid, the average particle size of the organic pigment is used. Is preferably 0.2 μm or more and 3.0 μm or less, and more preferably a hollow type having a void ratio of 40% or more.
As the binder, it is preferable to use an aqueous resin.
As the water-based resin, at least one of a water-soluble resin and a water-dispersible resin is preferably used.

The water-soluble resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a modified product of polyvinyl alcohol such as polyvinyl alcohol, anion-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, and acetal-modified polyvinyl alcohol; Polyvinyl; polyvinylpyrrolidone and a polymer of polyvinylpyrrolidone and vinyl acetate, a copolymer of vinylpyrrolidone and dimethylaminoethyl / methacrylic acid, a quaternized polymer of vinylpyrrolidone and dimethylaminoethyl / methacrylic acid, and vinylpyrrolidone. Modified products of polyvinylpyrrolidone such as a copolymer of methacrylamide propyl trimethylammonium chloride; cellulose such as carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose; modified products of cellulose such as cationized hydroxyethyl cellulose; polyester, polyacrylic acid (ester), Melamine resin or synthetic resins such as modified products thereof, polymers of polyester and polyurethane; poly (meth) acrylic acid, poly (meth) acrylamide, oxidized starch, phosphoric acid esterified starch, self-modified starch, cationized starch, Alternatively, various modified starches, polyethylene oxide, sodium polyacrylic acid, sodium alginate, and the like can be mentioned. These may be used alone or in combination of two or more.

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

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) acrylic acid ester copolymer weight. Combined, (meth) acrylic acid ester-based polymer, vinyl acetate- (meth) acrylic acid (ester) copolymer, styrene-butadiene copolymer, ethylene-propylene copolymer, polyvinyl ether, silicone-acrylic acid-based copolymer Coalescence, etc. Further, it may contain a cross-linking agent such as methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, or isocyanate, or may be a copolymer containing a unit such as N-methylolacrylamide having self-crosslinking property. It is also possible to use a plurality of these aqueous resins at the same time.

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 does not necessarily have to be blended, but there is no particular limitation, and the colorant can be appropriately selected and used depending on the intended purpose. For example, primary to tertiary amines and quaternary ammonium salt monomers and oligomers that react with direct dyes in water-soluble inks and sulfonic acid groups, carboxyl groups, amino groups, etc. in acid dyes to form insoluble salts. Examples thereof include polymers, and among these, oligomers or polymers are preferable.

Examples of the cationic organic compound include dimethylamine / epichlorohydrin polycondensate, dimethylamine / ammonium / epichlorohydrin condensate, poly (trimethylaminoethyl methacrylate / methyl sulfate), diallylamine hydrochloride / acrylamide copolymer, and poly. (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 / disyandiamidammonium salt condensate, dimethyldiallylammonium chloride, polydialylmethylamine hydrochloride, poly (diallyldimethylammonium chloride), poly (diallyldimethylammonium chloride / sulfur dioxide), poly (diallyldimethylammonium chloride / diallylamine) Hydrochloride derivatives), acrylamide / diallyldimethylammonium chloride copolymers, acrylicate / acrylamide / diallylamine hydrochloride copolymers, ethyleneimine derivatives such as polyethyleneimine and acrylicamine polymers, polyethyleneimine alkylene oxide modified products, etc. Be done. These may be used alone or in combination of two or more.

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) are used. It is preferable to use them in combination. When used in combination, the image density is improved and feathering is further reduced as compared with the case of single use.

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

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

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 anionic surfactant, cationic surfactant, amphoteric surfactant and nonionic surfactant is used. be able to. Of these, nonionic surfactants are particularly preferred. By adding the surfactant, the water resistance of the image is improved, the image density is increased, and the bleeding is improved.

Examples of the nonionic surfactant include higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher aliphatic amine ethylene oxide adduct, and fatty acid. Amidethylene oxide adduct, ethylene oxide adduct of fats and oils, 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. , Fatty acid amides of alkanolamines and the like. These may be used alone or in combination of two or more.

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 for the ethylene oxide adduct, it is also effective to replace a part of ethylene oxide with an alkylene oxide such as propylene oxide or butylene oxide as long as the 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 amount of the surfactant added 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 part 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 needed, as long as the object and effect of the present invention are not impaired. Examples of the other components include additives such as alumina powder, pH adjusters, preservatives, and antioxidants.

The method for forming the coating layer is not particularly limited and may be appropriately selected depending on the intended purpose, and can be carried out by impregnating or coating the coating layer liquid on the support. 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, a conventional size press, a gate roll size press, a film transfer size press, a blade coater, and a rod coater. , Air knife coater, curtain coater, etc. can be applied with various coating machines, but from the viewpoint of cost, the conventional size press, gate roll size press, film transfer size press, etc. installed in the paper machine can be used. It may be impregnated or applied and finished on-machine.

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

After the impregnation or coating, it may be dried if necessary, and the drying temperature in this case is not particularly limited and may be appropriately selected depending on the intended purpose, but is about 100 ° C. or higher and 250 ° C. or lower. Is preferable.

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

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The "maximum value of the logarithmic decrement" and the "time at which the logarithmic decrement takes the maximum value" used in the following Examples and Comparative Examples were measured as follows.

(Maximum value of logarithmic decrement and time when logarithmic decrement reaches maximum value)
The maximum value of the logarithmic decrement and the time for the logarithmic decrement to reach the maximum value were measured using a rigid pendulum type physical property tester (device name: RPT-3000W, manufactured by A & D Co., Ltd.).
Specifically, 40 μL of ink was dropped onto an aluminum substrate, and an ink film having 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 placed 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 the temperature was kept at 60 ° C. The logarithmic decrement was plotted every 6 seconds with the time point at room temperature (25 ° C.) as the measurement start time. The obtained plot was smoothed, the maximum value was calculated, and the maximum value of the logarithmic decrement was used. The time at which the logarithmic decrement reaches the maximum value is the time from the start of measurement until the logarithmic decrement reaches the maximum value.
The logarithmic decrement (D'(n)) after the smoothing can be obtained as follows when the logarithmic decrement 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 liquid 1>
Titanium tetraisopropoxide in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube so that 1,6-hexanediol and 1,6-hexanediacid are OH / COOH = 1.5. It was charged together with (1,000 ppm (1% by mass) vs. resin component). Then, the temperature was raised to 200 ° C. in about 4 hours. Then, the temperature was raised to 230 ° C. over 2 hours, and the reaction was carried out until the runoff water disappeared. Then, the reaction was further carried out under reduced pressure of 1,334 Pa to 2,000 Pa (10 mmHg to 15 mmHg) for 5 hours to obtain an intermediate polyester.
Next, the intermediate polyester and isophorone diisocyanate were placed in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube at a molar ratio of 2.0, and diluted with ethyl acetate to a molar ratio of 48% by mass. After that, it was reacted at 100 ° C. for 5 hours. Then, a large amount of water was added and desolubilized to obtain a polyurethane resin particle dispersion liquid 1 having a solid content concentration of 10% by mass.

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

<Preparation of polyurethane resin particle dispersion liquid 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-hexanediic acid was changed to 1,4-butanediol. Except for the above, the polyurethane resin particle dispersion liquid 3 having a solid content concentration of 10% by mass was obtained in the same manner as in the preparation of the polyurethane resin particle dispersion liquid 1.

<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 (manufactured by 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:) 10% by mass) 50.0% by mass, and the remaining amount of ultrapure water was added so that the total was 100% by mass, and the mixture was stirred and mixed to obtain ink 1.

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

In Tables 1 to 3 above, the product names of the ingredients and the names of the manufacturing companies are as follows.
-Cyan pigment: manufactured by Dainichiseika Kogyo Co., Ltd., product name: Pigment Blue 15: 3
-Magenta pigment: manufactured by Dainichiseika Kogyo Co., Ltd., product name: Pigment Red 122
-Yellow pigment: manufactured by Dainichiseika Kogyo Co., Ltd., product name: Pigment Yellow 154
・ Tripropylene glycol monobutyl ether: manufactured by Dow Chemical Japan Co., Ltd. ・ Triethylene glycol dimethyl ether: manufactured by Dow Chemical Japan Co., Ltd. ・ Diethylene glycol ethyl methyl ether: manufactured by Dow Chemical Japan Co., Ltd. ・ Dipropylene glycol dimethyl ether: Dow Chemical Japan Made by Tripropylene Glycol Dimethyl Ether: Dow Chemical Japan Co., Ltd. 1,2-Propylene Diol (Propylene Glycol): Made by Kanto Chemical Co., Ltd.

(Examples 1 to 35 and Comparative Examples 1 to 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, as shown in Table 4 below, a 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. Then, a solid image was recorded at a resolution of 1,200 dpi. The take-up device uses a Rewinding module RW6 (manufactured by Hunkeller) to take up the pressure as shown in Tables 4 and 5 below, and "blocking resistance", "rubbing 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, after the recording is completed once, 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 deviation at the time of applying the second ink" was evaluated. The take-up pressure was measured using the device 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 absorptometer (DSA, Paper Technology Cooperative Magazine, Vol. 48, May 1994, pp. 88-92, Shigenori Kukan). The transfer amount of pure water in the ^{above is 2.9 mL / m 2} , and the transfer amount of pure water in the contact time of 400 ms is 4.9 mL / m ² .

In the Magno Plus Silk, the contact time measured by a dynamic scanning absorptometer (DSA, Paper Technology Cooperative Magazine, Vol. 48, May 1994, pp. 88-92, Shigenori Kusaka) The transfer amount of pure water in the ^{above is 2.5 mL / m 2} , and the transfer amount of pure water in the contact time of 400 ms is 4.3 mL / m ² .

In the Magno Gloss, at a contact time of 100 ms measured by a dynamic scanning absorptometer (DSA, Paper Technology Cooperative Magazine, Vol. 48, May 1994, pp. 88-92, Shigenori Kuga). 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 degree of sticking between the recorded images and the state of image transfer (offset) were visually confirmed, and the "blocking resistance" was evaluated based on the following evaluation criteria. Rank 7 or higher is good in terms of quality, and rank 10 is particularly good. In addition, rank 3 or lower significantly reduces the quality.
〔Evaluation criteria〕
10: The papers do not stick to each other, the image does not peel off, and the image is visually uniform. 9: The papers do not stick to each other, there is no image peeling, but there is a minute image omission of less than 10 μm 8: Paper does not stick to each other and there is no image peeling, but there is a minute image omission of 10 μm or more and less than 20 μm. 7: Paper does not stick to each other and there is no image peeling, but there is a minute image omission of 20 μm or more and less than 30 μm. 3: Papers are stuck together and the image is significantly chipped 1: Papers are stuck together and the image is markedly chipped, and the paper is also markedly chipped 0: Papers are stuck together and united

(Scratch resistance)
For each of the obtained images, the images were rubbed 20 times with paper (LAG90 (manufactured by Stora Enso)) cut into 1.2 cm squares, and a reflective color spectrophotometric densitometer (manufactured by X-Rite) was used. The stain on the paper was measured, the density was calculated by subtracting the background color of the rubbed paper, and the "rubbing resistance" was evaluated based on the following evaluation criteria. The permissible ranges are A and B.
〔Evaluation criteria〕
A: Transfer concentration is less than 0.05 B: Transfer concentration is 0.05 or more and less than 0.10 C: Transfer concentration is 0.10 or more

(Glossiness)
For each of the obtained images, a 60 ° gloss was measured using a gloss meter (manufactured by BYK Gardener: Micro-TRI-Gloss 4520), and the "glossiness" before and after pressurization was evaluated. In addition, when the image transfer (offset) occurred, it was displayed as no value (“−” in Table 4) because it could not be measured.

(Position shift when applying the second ink)
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 permissible range is A.
〔Evaluation criteria〕
A: No misalignment B: Misaligned

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

Japanese Patent No. 5445220

1 Image forming apparatus 2 Recording medium 3 Paper feeding means 4 Ink applying means (first ink applying means)
5 Pressurizing means

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

The image forming apparatus of the present invention to solve the above problems, has a first ink application means to form an image by applying a first ink on the recording medium, the first ink, water, an organic solvent , Urethane resin particles, and copper phthalocyanine pigment, the organic solvent contains an ether compound having no hydroxyl group, and the first ink is a rigid body of an ink film formed by using the first ink. logarithmic decrement when measured under the conditions of 60 ° C. by the pendulum test takes a maximum value in the following 7200 seconds, and the maximum value is below 0.300 or less.

Claims (11)

A first ink applying means for applying the first ink to a recording medium to form an image, and a first ink applying means.
It has a pressurizing means that applies pressure to the image.
The first ink contains water, an organic solvent, and a copper phthalocyanine pigment.
The first ink has a maximum logarithmic decrement rate of 7200 seconds or less when an ink film formed by using the first ink is measured by a rigid pendulum test under a condition of 60 ° C., and the maximum value is obtained. It has the property that the value is 0.300 or less, and has a value of 0.300 or less.
An image forming apparatus in which 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 means is a means for applying 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 means for applying a second ink to the continuous paper to which the pressure has been applied to form an image. The recording medium has a support and a coating layer provided on at least one surface side of the support, and the recording medium of pure water having a contact time of 100 ms measured by a dynamic scanning liquid absorbent meter. 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 device. The recording medium is continuous paper.
The pressurizing means is a 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 surface side of the support, and the recording medium of pure water having a contact time of 100 ms measured by a dynamic scanning liquid absorbent meter. The image forming apparatus according to claim 1, ^{wherein the transfer amount to the recording medium is 2} to 35 ml / m 2, and the 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 any one of claims 1 to 5, wherein the first ink contains urethane resin particles. The image forming apparatus according to claim 6, wherein the organic solvent contains 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, in the general formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 or more and 10 or less carbon atoms, and R ² and R ³ independently represent an alkyl group having 1 or more and 10 or less carbon atoms. Represents, and n represents an integer of 1 or more and 5 or less. The mass ratio (ether compound / urethane resin particles) of the content (mass%) of the urethane resin particles to the total amount of the first ink and the content (mass%) of the ether compound to the total amount of the first ink is , The image forming apparatus according to claim 7 or 8, wherein the image forming apparatus is 0.40 or more and 1.60 or less. The image forming apparatus according to any one of claims 7 to 9, wherein the content of the ether compound with respect to the total amount of the first ink is 2.0% by mass or more and 8.0% by mass or less. The first ink application step of applying the first ink to the recording medium to form an image, and
It has 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 has a maximum logarithmic decrement rate of 7200 seconds or less when an ink film formed by using the first ink is measured by a rigid pendulum test under a condition of 60 ° C., and the maximum value is obtained. It has the property that the value is 0.300 or less, and has a value of 0.300 or less.
An image forming method in which the pressure is 3.5 kg / cm ² or more and 16.0 kg / cm ^{2 or less.}

Images