JP6841160B2 - Image forming method, image forming apparatus, image forming system, and method for manufacturing an image forming product. - Google Patents

Description

The present invention relates to an image forming method, an image forming apparatus, an image forming system, and a method for producing an image forming product.

The inkjet recording method has advantages such as low noise of the equipment used, good operability, easy full-color printing, and the ability to form images on various recording media. It is used not only in homes and offices but also in industrial applications. It is also used in commercial printing. In commercial printing, solvent inks, UV inks, and the like have been used due to the demand for forming images on recording media having low absorbency such as coated paper. However, in recent years, the use of water-based inks has been desired in commercial printing because of its environmental friendliness. Further, in commercial printing, continuous paper may be used as a recording medium.

Patent Document 1 discloses an inkjet recording device that uses continuous paper rolled into a roll.

However, since the water-based ink has low permeability to the recording medium, the pigment may not be firmly fixed to the recording medium when forming an image using the water-based ink. For this reason, when pressure is applied to the image in the process of winding the recording medium after forming the image using the water-based ink, the image is mottled and blocked (the image is transferred when the recording medium after image formation is overlaid). Or, there arises a problem that rubbing (images are rubbed when the recording media after image formation are overlapped) occurs.

The image forming method of the invention according to claim 1 includes a first ink applying step of applying one or more inks containing magenta ink to a recording medium to form an image, and a recording medium to which the one or more inks are applied. The ink contains water, an organic solvent, and a coloring material, and the magenta ink contains an azo pigment as the coloring material and is formed of the magenta ink. The tack force of the ink film is 80 nN or more and 110 nN or less.

According to the present invention, when an image is formed using a water-based ink, even if pressure is applied to the image in the step of winding up the recording medium, it is possible to reduce the occurrence of mottle, blocking, and rubbing in the image. ..

FIG. 1 is a micrograph of a solid image formed by using My Paper (manufactured by Ricoh Corporation) as a recording medium and magenta ink containing quinacridone as an ink. FIG. 2 is a photomicrograph of a solid image formed by using My Paper (manufactured by Ricoh Corporation) as a recording medium and magenta ink containing an azo pigment (PR57: 1) as an ink. FIG. 3 shows an example of the force curve obtained in the measurement of the tack force. FIG. 4 is a schematic view showing an image forming apparatus according to an embodiment of the present invention. FIG. 5 is a plan view of a head unit included in the image forming unit of the inkjet recording device of FIG. FIG. 6 is a photograph showing an example of a cantilever provided with a spherical probe. FIG. 7 is a perspective view showing an example of continuous paper. FIG. 8 is a side view of the continuous paper of FIG. 7.

Hereinafter, embodiments for carrying out the present invention will be described, but the present invention is not limited to the following embodiments.

A resin emulsion may be included in the composition of the ink in order to improve the fixability of the ink to the recording medium. However, when the resin emulsion is included in the composition of the ink, the resin has high elasticity, so that the tacking force of the formed image becomes large. When the tack force becomes large, the image is offset at the timing when pressure is applied to the image, such as when fixing the image using a fixing roller after forming the image, or when printing on roll paper and then winding the image. For example, when an image is formed on continuous paper using an image forming apparatus as shown in FIG. 4 described later, a large pressure is applied near the center of the roll when the continuous paper after ink is applied is applied to the image. May be offset. Further, when tension is applied to the continuous paper to wind up the recorded paper, a large pressure is applied not only near the center of the roll but also at the outer edge of the roll, and the image may be offset.

Therefore, the inventors have set the tack force of the ink film to 80 nN or more and 110 nN or less, preferably 85 nN, in order to obtain a good image that is not offset even when a winding pressure is applied in the winding step of the recording medium after image formation. An image forming method using an ink adjusted to 100 nN or less was examined. When the tack force of the ink film is 80 nN or more, the binding force of the ink film can be improved, the film strength is increased, and sufficient fixability can be obtained. When the tack force is 110 nN or less, the ink film is maintained by the force acting on the contact surface with the recording medium, so that it is possible to prevent the ink film from being destroyed when pressure is applied to the image, and it is possible to prevent the ink film from being destroyed. The offset is suppressed.

An example of a method of calculating the tack force of the ink film on the image surface will be described. An atomic force microscope (hereinafter, also referred to as "AFM", device name: SPM-9500J3, manufactured by Shimadzu Corporation) is used as a method for measuring the tack force on the image surface. As the image for measurement, an image output on a recording medium by various inkjet printers can be used.

FIG. 6 is a photograph showing an example of a cantilever provided with a spherical probe. As shown in FIG. 6, the AFM includes a cantilever 20, and the cantilever 20 is provided with a spherical probe 21. The cantilever 20 includes a spherical silicone oxide as the probe 21. The measurement is carried out under the conditions of a measurement temperature of 23 ° C., a humidity of 35% RH, a probe diameter of 3.5 μm, a measurement mode: force curve measurement, and a measurement frequency of 1 Hz.

At the time of measurement, the probe 21 of the AFM is brought into contact with the image, pushed in by 100 nm, and then the probe 21 is pulled up, and the bending of the cantilever 20 when moving away from the image is monitored as a displacement amount to obtain a force curve. FIG. 3 is a diagram showing an example of a force curve obtained in measuring the tack force on the surface of the ink film. The tack force can be a value (F = kx) obtained by multiplying the displacement amount x in FIG. 3 by the spring constant k of the cantilever 20 as shown in FIG.

By the way, as the inkjet method has become widespread as an industrial printing method and document display using an electronic information terminal or the like has become common, the performance required for industrial printed matter has also changed. For example, in industrial printing, unlike office and household printed matter, long-term storage is relatively less important, while producing good image quality, as represented by obtaining high-saturation images. The importance is relatively high.

Quinacridone, which is a magenta pigment generally used in the inkjet method, has excellent light resistance and solvent resistance because of its stable chemical bond and formation of strong crystals, but its coloring power is weak. Therefore, in order to enhance the saturation of the image, the inventors have increased the dispersibility of the quinacridone pigment and formed the image with magenta ink having an increased density, and the image forming method accompanied by pressure such as winding of roll paper. Then, I found that mottle occurs. The mottle is a density unevenness caused by the occurrence of a portion having a high pigment density and a portion having a low pigment density in an image formed on a recording medium. That is, there is a trade-off relationship between dispersibility and light resistance and solvent resistance, and if the dispersibility is improved, the light resistance and solvent resistance will be inferior.

Such mottle tends to occur when a recording medium having irregularities on the surface such as paper is used as the recording medium. FIG. 1 is a micrograph of a solid image formed by using My Paper (manufactured by Ricoh Corporation) as a recording medium and magenta ink containing quinacridone as an ink. As a microscope, an ultra-depth color 3D shape measuring microscope VK-9500 manufactured by Keyence Corporation was used (field of view range 280 × 210 um (1024 × 768 pix, 0.27 um / pix)). In FIG. 1, the portion that looks black is the portion where the magenta pigment is present. As a result of observing the printed image, the inventors found that the cause of the above-mentioned mottle was that the particle size of the quinacridone crystal was relatively large, and when the pigment concentration in the ink was increased, the dispersibility of the pigment was impaired. It was thought that the winding pressure would make it easier for pigment crystals to be unevenly distributed in the recesses of the recording medium.

The azo pigment is an organic pigment having an azo group, and has not been widely used in the conventional inkjet method due to concerns about the stability of the chemical structure. However, the azo pigment has a small particle size and is easily dispersed in water by introducing a hydrophilic group. Therefore, the inventors focused on magenta ink using an azo pigment.

FIG. 2 is a photomicrograph of a solid image formed by using My Paper (manufactured by Ricoh Corporation) as a recording medium and magenta ink containing an azo pigment (PR57: 1) as an ink. As a microscope, an ultra-depth color 3D shape measuring microscope VK-9500 manufactured by Keyence Corporation was used (field of view range 280 × 210 um (1024 × 768 pix, 0.27 um / pix)). In FIG. 2, the portion that looks black is the portion where the magenta pigment is present. Compared with FIG. 1, it can be seen that the black portion spreads uniformly.

As a result of further diligent studies on the material, physical properties, and treatment method of the ink, the inventors did not unevenly distribute the pigment in the recesses on the paper even when the image was formed with the winding pressure, and the ink was mottled. We have found an image forming method of the present invention suitable for an industrial inkjet method that is unlikely to occur. According to the image forming method of the present invention, the first ink applying step of applying one or more inks containing magenta ink to a recording medium to form an image and the recording medium to which one or more inks are applied are wound. The ink contains water, an organic solvent, and a coloring material, and the magenta ink contains an azo pigment as a coloring material, and the tacking force of the ink film formed by the ink is , 80 nN or more and 110 nN or less.

The image forming method of the present invention is based on the finding that the conventional image forming apparatus has a problem that the printing apparatus becomes large and the cost becomes high. That is, according to the above-mentioned image forming method, a continuous paper is used as a recording medium, a winding step of winding the recording medium in a roll shape is provided, and even when pressure is applied to an image, another special device is used. It is possible to form a mottled image without adding.

By the way, in the image forming method using continuous paper, after winding the continuous paper to which the ink was applied in the first ink application step in the winding step, the surface of the continuous paper to which the ink was applied is subjected to. A step (second ink applying step) called "addition printing" in which ink is applied again to form an image may be provided. At this time, if the winding pressure is large in the winding step after the first ink application step, the rolls are wound uniformly and additional printing can be performed appropriately, but as described above, the image is likely to be offset. .. On the other hand, if the take-up pressure is small, the roll bends and becomes a non-uniform state, and the paper is not conveyed at a constant speed during reprinting, so that the recording position is likely to shift.

According to the image forming method of the present invention, the continuous paper after image formation can be wound by applying sufficient pressure to prevent the occurrence of offset, misalignment, etc. even when the second ink applying step is provided. be able to. The image forming method of the present invention can solve the above-mentioned problems when reprinting on the surface on which the image is formed in the first ink applying step, but the second ink applying step is the first. It does not exclude the case where the ink application step is performed on the surface opposite to the surface on which the image is formed.

The tack force of the above ink is particularly affected by the type of resin in the ink and the like. The composition of the ink for achieving the above-mentioned predetermined tack force range will be described in detail below.

<Ink>
Hereinafter, the organic solvent, water, coloring material, resin, additive, etc. used for the ink will be described.

<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 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 ether, 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 glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers: Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether can be mentioned.

The boiling point of the organic solvent is preferably 180 ° C. or higher and 250 ° C. or lower. When the boiling point is 180 ° C. or higher, the evaporation rate at the time of drying can be appropriately adjusted, leveling is sufficiently performed, surface irregularities are reduced, and glossiness can be improved. Further, in order to improve the drying property, it is preferable to use a solvent having a boiling point of 250 ° C. or lower. With the speeding up of printing technology in recent years, the time required for ink drying has become rate-determining. By setting the boiling point of the organic solvent in the above range, it is possible to achieve high speed image formation by shortening the drying time.

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 ink drying property and ejection reliability. More preferably, it is 20% by mass or more and 60% by mass or less.

<Color material>
When forming a single color image, one ink may be used, but when forming a multi-color image, multiple color inks such as magenta ink, cyan ink, yellow ink, and black ink are used. Used. Coloring materials in magenta inks include azo pigments. When the pigment contains an azo pigment, since the particle size is small, it is possible to prevent uneven distribution in the recesses of the recording medium and suppress mottle. Examples of the azo pigment include PR57: 1, PR52: 1, PR146, PR53: 1, and PR48: 1, and PR57: 1, PR52: 1, and PR146 can easily obtain effects such as suppression of mottle. It is preferable to include one or more selected from the group, and PR57: 1 is more preferable.

The pigment used for the color material of the cyan ink is not particularly limited and may be appropriately selected depending on the intended purpose, but a phthalocyanine pigment is preferable. Examples of the phthalocyanine pigment include PR-15, PB15: 1, PB15: 2, PB15: 3, and PB15: 4. The pigment used for the color material of the yellow ink is not particularly limited and may be appropriately selected according to the intended purpose, but an azo pigment is preferable. Examples of the azo pigment include PY12 and PY13. If the pigment contained in the coloring material in the cyan ink and the yellow ink is the above example, the coverage rate for Japan Color ver.2 can be increased. Japan Color ver.2 is a printing color standard used for certification in the Japan Color certification system that complies with ISO international standards.

The pigments contained in the coloring material in black ink include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, or copper and iron (CI pigment black). 11), metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1) can be mentioned.

The content of the coloring material 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 image density, good fixability and ejection stability. It is as follows.

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 the pigment, 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 a pigment (for example, carbon) so that it can be dispersed in water, etc. Can be used.

As a method of coating the surface of the pigment with a resin and dispersing the pigment, 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 coating 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 effects of the present invention are 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 a 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 a naphthalene sulfonate 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 dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. It is preferable 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, 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, from the viewpoint of obtaining good ejection stability and increasing the image density, 0.1 mass is used. % 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. If necessary, the pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifuge, or the like.

<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, acrylic styrene resins, and acrylic silicone resins. 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 dispersed 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.

Examples of the urethane resin particles include polycarbonate urethane resin particles, polyester urethane resin particles, and polyether urethane resin particles. These may be used alone or in combination of two or more. Among these, polycarbonate urethane resin particles are preferable from the viewpoint of abrasion resistance. The polycarbonate urethane resin particles may have a polycarbonate structure in the structure.

The glass transition temperature (Tg) of the urethane resin particles is preferably −20 ° C. or higher and 70 ° C. or lower. Urethane resin particles having a glass transition temperature (Tg) of -20 ° C or higher and 70 ° C or lower have a particularly large tack force when the ink is formed into an ink film, further improve the fixability, and exhibit good rubbing resistance. ..

Acrylic resin particles are excellent in discharge stability and cost, and are suitable as a resin. Examples of the acrylic resin particles include acrylic silicone resin particles and styrene-acrylic resin particles. These may be used alone or in combination of two or more. Among these, acrylic silicone resin particles are preferable from the viewpoint of abrasion resistance.

Urethane resin particles may reduce blocking resistance when used alone, so it is preferable to use them in combination with other resin particles. Further, since the acrylic resin particles may be inferior in abrasion resistance when used alone, it is preferable to use them in combination with elastic urethane resin particles. When acrylic resin and urethane resin are used together, the mass ratio of the content of urethane resin particles (mass%) and the content of acrylic resin particles (mass%) in the ink (urethane resin particles / acrylic resin particles) The amount is not particularly limited, but is preferably 0.1 or more and 0.7 or less. When the mass ratio (urethane resin particles / acrylic resin particles) is 0.1 or more and 0.7 or less, the tack force when the ink film formed by using ink is measured by an atomic force microscope (AFM). Tends to fall within the range of 80 nN or more and 110 nN or less.

An ink film formed of an ink having a mass ratio (urethane resin particles / acrylic resin particles) of 0.1 or more and 0.7 or less is subjected to Fourier transform infrared absorption spectrum method (hereinafter, also referred to as “FTIR”). when measured, the tangential line connecting the region from the spectrum 692cm ^-1 to 707cm ^-1, the minimum point between 690 cm ^-1 or less the minimum point and spectrum 660 cm ^-1 or more between the spectrum 710 cm ^-1 or more 740 cm ^-1 or less , a region of the area a, and from the spectrum 1,731Cm ^-1 to 1,750Cm ^-1 peak area enclosed by the minimum point and spectrum 1 of between spectral 1,660Cm ^-1 to 1,690Cm ^-1, the tangent connecting the minimum point of between 760 cm ^-1 to 1,790Cm ^-1, the area ratio of the area B of the peak area surrounded by (B / a) is preferably 0.3 to 1.0, 0 More preferably, it is 6.6 or more and 1.0 or less. When the area ratio (B / A) is 0.3 or more and 1.0 or less, both the effect of improving the rubbing resistance by the urethane resin particles and the effect of improving the discharge stability by the acrylic resin particles can be achieved. ..

The ATR (Attenated Total Reflection) method of the Fourier transform infrared spectrophotometer may be used for the measurement of the Fourier transform infrared absorption spectrum method of the ink film. Specifically, the surface of the ink film formed on paper (trade name: Lumi Art Gloss 130gsm, manufactured by Stora Enso) with an ink adhesion amount of 1.12 ^{mg / cm 2 (700 mg / A4) is used as the device name.} : It can be determined from the spectrum measured by the ATR method using a diamond indenter using Spectrum One (manufactured by PerkinElmer).

The volume average particle diameter 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 Microtrack 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 Microtrack Bell Co., Ltd.).

<Water>
The water is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ion-exchanged water such as ion-exchanged high-pure water, ultrapure filtered water, reverse osmosis water, pure water such as distilled water; ultrapure water. And so on. These may be used alone or in combination of two or more.

The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of ink drying property and ejection reliability, 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, a defoaming agent, an antiseptic / antifungal agent, a rust preventive, a pH adjuster, or 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, and side chain double-ended modified polydimethylsiloxane. 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 a compound 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 compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property. 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 counterions of the salts in these fluorine-based surfactants are Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH). ₃ etc. can be mentioned.

Examples of the amphoteric tenside agent include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, and lauryldihydroxyethylbetaine.
Examples of nonionic surfactants include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include ethylene oxide adducts of fatty acid esters and acetylene alcohols.

Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, salt of polyoxyethylene alkyl ether sulfate, and the like. These may be used alone or in combination of two or more.

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 and a polyoxyethylene polyoxypropylene group as modifying groups 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, the polyalkylene oxide structure represented by the general formula (S-1) is dimethylpoly. Examples thereof include those introduced into the Si part side chain of siloxane.

General formula (S-1)
(However, in the general formula (S-1), m, n, a, and b represent integers. R and R'represent an alkyl group and an alkylene 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.

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 fluorine-based surfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because it has low 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.

General formula (F-1)

In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10, and n is preferably an integer of 0 to 40 in order to impart water solubility.
General formula (F-2)
C _n F _{2n + 1-} CH ₂ CH (OH) CH _2- O- (CH ₂ CH ₂ O) _a- Y
In the compound represented by the above general formula (F-2), Y is H or CnF _{2n + 1} and n is an integer of 1 to 6, or CH ₂ CH (OH) CH _2- CnF _{2n + 1} and n is 4 to 6. It is an integer, or CpH _{2p + 1} and p is an integer of 1-19. 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 (all) , Du Pont); 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, Ltd.), etc. Among these, good print quality, especially color development and penetration into paper. FS-300 manufactured by DuPont, FT-110, FT-250, FT-251, FT-400S, FT-150, FT manufactured by Neos Co., Ltd. from the viewpoint of significantly improving property, wettability, and leveling property. -400SW, Polyfox PF-151N manufactured by Omniova Co., Ltd. and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are 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 a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. 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.

<Rust inhibitor>
The rust preventive is not particularly limited, and examples thereof include acidic sulfites 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'x 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, 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, more preferably 8 to 11, from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

<Recording medium>
The recording medium is not particularly limited and may be appropriately selected depending on the intended purpose, and examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper. An effective recording medium in the present embodiment includes a support and 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 is exemplified.

A recording medium having a support and a coating layer is generally called coated paper, and is known as a recording medium having low ink permeability. When an image is formed on a recording medium having low permeability such as coated paper using a water-based ink, it is difficult to firmly fix the color material on the recording medium, and the abrasion resistance is often lowered. However, if 80nN more 110nN less tack force of the ink film, even by applying a pressure of 3.5 kg / cm ² or more 8.0 kg / cm ² or less after the image formation does not occur blocking, a good further gloss This is preferable because an image can be obtained.

-Support-
The support is not particularly limited, and is appropriately selected depending on the intended purpose, and examples thereof include paper mainly composed of wood fibers and sheet-like substances such as non-woven fabric mainly composed of wood fibers and synthetic fibers.

The paper is not particularly limited and is appropriately selected according to the purpose, and wood pulp, used paper pulp and the like are exemplified. Examples of wood pulp include hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), NBSP, LBSP, GP, TMP and the like.

As raw materials for used paper pulp, fine white, ruled white, cream white, card, special white, medium white, imitation, fair white, Kent, white art shown in the used paper standard quality standard table of the Waste Paper Recycling Promotion Center , Special cut, special cut, newspaper, magazine, etc. are exemplified. Specifically, as a raw material for waste paper pulp, non-coated computer paper, heat-sensitive paper, pressure-sensitive paper and other printer papers; OA waste paper such as PPC paper; art paper, coated paper, finely coated paper, matte Painted paper such as paper; high-quality paper, high-quality color, notebook, letter paper, wrapping paper, fancy paper, medium-quality paper, newspaper paper, stencil paper, super hanging paper, imitation paper, pure white roll paper, milk carton, etc. Examples of used paper such as work 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. 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 recording.

Recycled paper pulp can generally be produced from a combination of the following four steps.
(1) In the disintegration step, 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) In the dust removal process, foreign substances (plastic, etc.) and dust contained in the used paper are removed by a screen, a cleaner, or the like.
(3) In the deinking step, 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) In the bleaching step, the whiteness of the fiber is increased by using an oxidizing action and a reducing action.

Examples of the internal filler used for the support include conventionally known pigments as white pigments. White pigments 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, silica soil, calcium silicate, White inorganic pigments such as magnesium silicate, synthetic silica, aluminum hydroxide, alumina, lithopone, zeolite, magnesium carbonate, magnesium hydroxide, etc .; styrene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins, melamine resins Organic pigments such as, etc. are exemplified. These may be used alone or in combination of two or more.

Internal sizing agents used when making supports include neutral rosin-based sizing agents used for neutral papermaking, alkenyl succinic anhydride (ASA), alkyl ketene dimer (AKD), and petroleum resin-based sizing agents. Etc. are exemplified. Of these, neutral rosin sizing agents or alkenyl succinic anhydride are particularly suitable. Alkyl ketene dimer requires a small amount to be added 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) decreases and it becomes slippery. There is.

-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 means a layer that may contain a pigment and a binder (binding agent), regardless of the forming method such as whether or not the coating layer is actually coated. To do.

As the pigment, an inorganic pigment or a combination of an inorganic pigment and an organic pigment can be used. Inorganic pigments 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, zinc hydroxide. , Chlorite and the like are exemplified. Among these, kaolin is particularly preferable because it has excellent gloss development and can have a texture close to that of paper for offset printing.

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

The content of 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 of styrene-acrylic copolymer particles, styrene-butadiene copolymer particles, polystyrene particles, polyethylene particles and the like. Two or more of these organic pigments may be mixed and used.

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 has excellent 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 of obtaining a coating layer having a bulky, high gloss and good surface coating property can be improved, and when the content is 20 parts by mass or less, the fluidity of the coating liquid is excellent. , Coating operability can be improved, and it is economical in terms of cost.

In its form, the organic pigment includes a solid type, a hollow type, a donut type and the like. Considering the balance between gloss development, surface coating property and fluidity of the coating liquid, the average particle size of the organic pigment is preferably 0.2 μm or more and 3.0 μm or less, and more preferably a hollow type having a porosity of 40% or more.

As the binder, it is preferable to use an aqueous resin. As the water-based resin, it is preferable to use at least one of a water-soluble resin and a water-dispersible resin. The water-soluble resin is not particularly limited and may be appropriately selected depending on the intended purpose. Modified products of polyvinyl alcohol such as polyvinyl alcohol, anion-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, and acetal-modified polyvinyl alcohol; polyurethane; polyvinyl Pyrrolidone and a copolymer of polyvinylpyrrolidone and vinyl acetate, a copolymer of vinylpyrrolidone and dimethylaminoethyl / methacrylic acid, a quaternized copolymer of vinylpyrrolidone and dimethylaminoethyl / methacrylic acid, vinylpyrrolidone and methacrylicamidepropyl Modified products of polyvinylpyrrolidone such as copolymers of trimethylammonium chloride; celluloses 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 these modified products, synthetic resins such as polyester and polyurethane copolymers; poly (meth) acrylic acid, poly (meth) acrylamide, oxidized starch, phosphoric acid esterified starch, self-modified starch, cationized starch, or various modifications. Examples include starch, polyethylene oxide, sodium polyacrylic acid, sodium alginate, and the like. 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 absorbency.

The water-dispersible resin is not particularly limited and may be appropriately selected depending on the intended purpose: polyvinyl acetate, ethylene-vinyl acetate copolymer, polystyrene, styrene- (meth) acrylic acid ester copolymer, (meth) acrylic. Examples thereof include acid ester-based polymers, vinyl acetate- (meth) acrylic acid (ester) copolymers, styrene-butadiene copolymers, ethylene-propylene copolymers, polyvinyl ethers, and silicone-acrylic copolymers. Will be done. Further, the aqueous resin may contain a cross-linking agent such as methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, or isocyanate, and is a copolymer containing a unit such as N-methylolacrylamide and has self-crosslinking property. It may be one. It is also possible to use a plurality of these water-based 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, 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, depending on the setting of the liquid absorption characteristics of the recording medium. Will be decided as appropriate.

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 it can be appropriately selected and used according to the purpose. Cationic organic compounds include primary to tertiary amines and quaternary ammonium salts 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 monomers, oligomers, and polymers of the above, and among these, oligomers or polymers are preferable.

Cationic organic compounds include dimethylamine / epichlorohydrin polycondensate, dimethylamine / ammonia / epichlorohydrin condensate, poly (trimethylaminoethyl methacrylate / methylsulfate), diallylamine hydrochloride / acrylamide copolymer, poly (diallylamine hydrochloride). Salt / sulfur dioxide), polyallylamine hydrochloride, poly (allylamine hydrochloride / diallylamine hydrochloride), acrylamide / diallylamine copolymer, polyvinylamine copolymer, dicyandiamide, dicyandiamide / ammonium chloride / urea / formaldehyde condensate, polyalkylene Polyamine / disyandiamideammonium salt condensate, dimethyldialylammonium chloride, polydiallylmethylamine hydrochloride, poly (diallyldimethylammonium chloride), poly (diallyldimethylammonium chloride / sulfur dioxide), poly (diallyldimethylammonium chloride / diallylamine hydrochloride derivative) ), acrylamide / diallyldimethylammonium chloride copolymer, acrylate / acrylamide / diallylamine hydrochloride copolymer, ethyleneimine derivatives such as polyethyleneimine and acrylicamine polymer, and polyethyleneimine alkylene oxide modified products. .. 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 or 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 cation equivalent of the cationic organic compound by the colloid titration method (using 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 colloid titration method, the cationic organic compound is diluted with distilled water so as to have a solid content of 0.1% by mass, and 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, 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, but any of anionic surfactant, cationic surfactant, amphoteric surfactant and nonionic surfactant may be used. it can. 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.

Non-ionic surfactants include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher aliphatic amine ethylene oxide adducts, and fatty acid amide ethylene oxide adducts. Additives, ethylene oxide adducts for fats and oils, polypropylene glycol ethylene oxide adducts, fatty acid esters for glycerol, fatty acid esters for pentaerythritol, fatty acid esters for sorbitol and sorbitan, fatty acid esters for sucrose, alkyl ethers for polyhydric alcohols, and alkanols. Examples thereof include fatty acid amides of amines. 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, and examples thereof include glycerol, trimethylolpropane, pentaerythlit, sorbitol, and sucrose. As for the ethylene oxide adduct, it is also effective to replace a part of the 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 / lipophilicity 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 parts by mass or less with respect to 100 parts by mass of the cationic organic compound.

Other components can be added to the coating layer as needed, as long as the object and effect of the present invention are not impaired. Examples of 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, a rod coater, etc. It is possible to apply with various coating machines such as air knife coater and curtain coater, but from the viewpoint of cost, it is impregnated with the conventional size press, gate roll size press, film transfer size press, etc. installed in the paper machine. Alternatively, it may be adhered and finished on-machine. The amount of the coating layer liquid adhered is not particularly limited and can be appropriately selected depending on the intended purpose. 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 more and 15 g. / M ² or less is more preferable. After impregnation or coating, it may be dried if necessary. In this case, the drying temperature 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. 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 is provided on the coating layer. You can also do it. Each of these layers may be a single layer or a plurality of layers.

Continuous paper can also be used as the recording medium. 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. Examples of continuous paper include roll paper rolled into a roll shape, continuous paper folded at predetermined intervals, and the like.

<< Image forming device >>
The image forming apparatus of the present invention includes one or more accommodating means for accommodating one or more inks including magenta ink, and one or more first ink applying means for applying one or more inks to a recording medium to form an image. There is no limitation as long as it has a winding means for winding the recording medium to which the ink is applied. Examples of the image forming apparatus include a printer, a facsimile apparatus, a copying apparatus, a multifunction device of a printer / facsimile / copying apparatus, and a three-dimensional modeling apparatus.

FIG. 4 is a schematic view showing an image forming apparatus according to an embodiment of the present invention. The inkjet recording device 300 shown in FIG. 4 includes a paper feed device 307, a recording medium transport unit 301 that conveys the recording medium 203, a pretreatment unit 302 that applies a pretreatment liquid to the conveyed recording medium 203, and a pretreatment liquid. A pretreatment liquid drying unit 303 that dries the recording medium 203 to which the above is applied, and an image forming unit 304 that forms an image on the recording medium 203 (an example of the first ink applying means, an example of the second ink applying means). The post-treatment unit 305 that applies the post-treatment liquid to the recording medium 203 after image formation, the post-treatment liquid drying unit 306 that dries the recording medium 203 to which the post-treatment liquid is applied, and the recording medium 203 on which the image is formed. It has a take-up device 308 (an example of a take-up means) and a take-up device 308.

The recording medium transport unit 301 is provided in the paper feed device 307, the pretreatment unit 302, the pretreatment liquid drying unit 303, the image forming unit 304, the post-processing unit 305, the post-processing liquid drying unit 306, and the winding device 308. It is constructed by multiple transfer rollers. The paper feeding device 307 is a means for feeding the recording medium 203 to a position where the image forming unit 304 applies ink. The recording medium 203 is continuous paper wound in a roll shape. The recording medium 203 is unwound from the paper feed device 307 by the transfer roller, conveyed on the platen, and wound by the take-up device 308.

The pretreatment unit 302 applies the pretreatment liquid to the recording medium 203 conveyed by the recording medium transfer unit 301. In the inkjet recording method, when an image is formed on a recording medium other than the inkjet paper, the quality such as bleeding, density, color tone and show-through deteriorates, and the quality related to image fastness such as water resistance and weather resistance deteriorates. Sometimes. By applying a pretreatment liquid having a function of aggregating ink to a recording medium before forming an image by the pretreatment unit 302, it is possible to prevent these deteriorations in quality. As the pretreatment liquid, any one can be used as long as it can prevent the above-mentioned deterioration in quality, and there is no particular limitation.

As the pretreatment method, a coating method in which the above pretreatment liquid is uniformly applied to the surface of the printing paper may be used, and there is no particular limitation. Such coating methods include blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, and smoothing. Examples thereof include a coating method, a microgravure coating method, a reverse roll coating method, a 4- to 5-roll coating method, a dip coating method, a curtain coating method, a slide coating method, and a die coating method.

The pretreatment liquid drying unit 303 includes heat rollers 311, 312. The continuous paper coated with the pretreatment liquid is conveyed to the heat rollers 311, 312 by the conveying roller. The heat rollers 311, 312 are heated to a high temperature of 50 ° C. or higher and 100 ° C. or lower, and the moisture content of the pretreatment liquid applied to the continuous paper evaporates and dries due to the contact heat transfer from the heat rollers 311, 312.

The image forming unit 304 applies ink to the fed recording medium 203 to form an image. The image is not particularly limited as long as it can be visually identified by fixing the ink on the recording medium, and includes not only characters and symbols but also solid images and patterns. Examples of the image forming unit 304 include four head units that eject black (K), cyan (C), magenta (M), and yellow (Y) inks. The image forming unit 304 is not limited to the one using the inkjet recording method, and for example, the blade coating method, the gravure coating method, the bar coating method, the roll coating method, the dip coating method, the curtain coating method, the slide coating method, the die coating method, and the like. It may be the one using the spray coating method or the like.

When the inkjet recording method is used, the image forming unit 304 applies a stimulus to the ink to eject it. The stimulus is not particularly limited and may be appropriately selected depending on the intended purpose, and examples thereof include heat (temperature), pressure, vibration, and light. The stimulus may be used alone or in combination of two or more. Among these, heat and pressure are preferably used. Examples of the ink ejection mode include a piezo method, a thermal method, and an electrostatic method.

The size of the droplets of ink to be ejected is, for example, 3 pL or more and 40 pL or less, the ejection speed thereof is, for example, 5 m / s or more and 20 m / s or less, and the driving frequency thereof is, for example. It is 1 kHz or more, and its resolution is, for example, 300 dpi or more.

Each of the above head units may be provided with an accommodating body (an example of accommodating means) such as a sub tank for accommodating ink. The ink contained in the head unit may be supplied from another container as the main tank. Examples of other housing include cartridges that contain ink and are casing with resin or the like, bottles, and the like. In the cartridge, the inner bag of the ink may be contained in an aluminum pouch made of a resin such as polyethylene.

FIG. 5 is a plan view of a head unit included in the image forming unit of the inkjet recording device of FIG. As shown in FIG. 5, a nozzle array in which a plurality of nozzles 310 are arranged is formed on the nozzle surface 309 of the head unit 304H along the longitudinal direction of the head unit 304H. In the present embodiment, the nozzle row is one row, but a plurality of rows may be provided. The head unit 304H may be provided for each color of ink to be used.

Like the image forming unit 304, the post-processing unit 305 has a head unit and applies the post-processing liquid to the recording medium after image formation. Any known post-treatment liquid can be used. The method of applying the post-treatment liquid is not limited to the inkjet method, and may be, for example, the same method as the method of applying the pre-treatment liquid.

The post-treatment liquid drying unit 306 includes heat rollers 313 and 314. The continuous paper coated with the post-treatment liquid is conveyed to the heat rollers 313 and 314 by the conveying roller. The heat roller is heated to a high temperature, and the moisture content of the post-treatment liquid applied to the continuous paper evaporates and dries due to the contact heat transfer from the heat rollers 313 and 314. The drying means is not limited to this, and an infrared drying device, a microwave drying device, warm air, etc. can be applied. Instead of using a single device, for example, a heat roller and a warm air device can be combined. May be good.

The winding device 308 is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a Rewinding module RW6 (manufactured by Hunkeler) or the like can be used. In the inkjet recording device 300, the winding device 308 also functions as a pressurizing means for applying pressure to the image unit formed on the recording medium 203. That is, the winding device 308 winds the recording medium 203 after the image is formed in a roll shape, and in the process of winding the recording medium 203 in a roll shape, pressure is applied to the recording medium 203. In particular, in the vicinity of the rotation axis of the winding device 308, a large pressure is applied due to the weight of the recording medium 203.

Further, when the winding device 308 winds up the recording medium 203, tension is applied to the recording medium 203, so that pressure is also applied to the recording medium 203 at the outer edge of the winding device 308. In this case, the pressure applied to the recording medium 203 can be adjusted by adjusting the tension acting on the recording medium 203. For example, the tension acting on the recording medium 203 can be adjusted by adjusting the rotation speeds of the paper feeding device 307 and the winding device 308, respectively.

<< Image formation system >>
The image forming system of the present invention includes one or more accommodating means for accommodating one or more inks including magenta ink, and one or more first ink applying means for applying one or more inks to a recording medium to form an image. There is no limitation as long as it has a winding means for winding the recording medium to which the ink is applied. The image forming system of the present invention is constructed by, for example, a plurality of devices provided with the accommodating means, the first ink applying means, or the winding means in the above-mentioned image forming device.

<< Image forming method and manufacturing method of image forming material >>
The image forming method and the method for producing an image forming product of the present invention include a first ink applying step of applying one or more inks containing magenta ink to a recording medium to form an image, and one or more inks. There is no limitation as long as it has a winding step of winding the given recording medium.

<First ink application process>
In the first ink application step, the image forming unit 304 applies one or more of the above inks to form an image on the recording medium. One or more of the above-mentioned inks may contain magenta ink, and may further include cyan ink, yellow ink, black ink and the like as other inks. Magenta ink, cyan ink, yellow ink, and black ink are inks containing colorants of magenta, cyan, yellow, and black, respectively. The formed image is not limited to significant ones such as characters and figures, and includes, for example, patterns such as geometric patterns and three-dimensional images.

<Winding process>
This is a winding process for winding a recording medium to which one or more inks are applied. As an example of the winding process, in the inkjet recording device 300, the winding device 308 winds the continuous paper to which ink is applied by the winding device 308. As a result, pressure is applied to the continuous paper to which the ink is applied.

The pressure applied to the image is not limited to that generated by winding continuous paper in a roll shape, and may be any pressure that is actively or passively generated. The pressure may be applied, for example, when the cut papers are laminated, or when the continuous paper or the cut paper is cut, and a roller for improving the fixability after recording or a post-treatment liquid is applied. It may be added by a roller of. Further, the pressure may be applied in a plurality of steps or in one step. Further, the pressure may be applied to at least a part of the recording medium, but it is preferable that the pressure is applied to the entire recording medium.

The pressure applied to the image, preferably 3.5 kg / cm ² or more 8.0 kg / cm ² or less, 3.7 kg / cm ² or more 7.9 kg / cm ² or less being more preferred. When the pressure is 3.5 kg / cm ² or more, sufficient image fixability can be obtained, the rubbing resistance can be improved, ^{and when the pressure is 8.0 kg / cm 2} or less, the image is a pressure roller. It is possible to prevent offsetting to overlapping images or paper. Further, a pigment is an azo pigment contained in the coloring material in the magenta ink, when the tackiness of the ink film is less 110nN least 80NN, after image formation, 3.5 kg / cm ² or more 8.0 kg / cm ² When the following pressure is applied, mottle is suppressed, blocking does not occur, and an image having good fixability can be obtained. Further, the image tack force is less 110nN least 80nN, 3.5kg / cm ² or more 8.0 kg / cm ² by applying a pressure below, the blocking does not occur, fixability was good, still gloss An excellent image forming product can be obtained.

When a pressure within the above-mentioned predetermined pressure range is applied, the image in the above-mentioned tack force range does not cause offset, has good blocking resistance, and can improve the fixability of the image and has high gloss. Since an image can be obtained and a sufficient winding pressure is applied within the pressure range, an additional effect that reprinting can be performed without any problem can be obtained.

The pressure measuring method is not particularly limited, and a known method can be appropriately selected depending on the intended purpose. As the pressure measuring device, for example, the surface pressure distribution measuring system I-SCAN (manufactured by Nitta Corporation) can be used, and as the sensor sheet, for example, I-SCAN # 5027 (manufactured by Nitta Corporation) can be used. Specific examples of measurement will be described in Examples.

The pressure applied to the roll-shaped continuous paper may be calculated by referring to, for example, the diameter, height, and mass of the roll-shaped continuous paper from photographs and information of the roll-shaped continuous paper.

<Second ink application process>
The image forming method of the present invention may include a second ink applying step of further applying ink to the continuous paper to form an image after the winding step. The second ink applying step is not particularly limited, but the continuous paper wound by the winding device 308 after image formation is set in the paper feeding device 307, and the first ink is applied by the inkjet recording device 300. A method of applying the second ink in the same manner as in the process is exemplified.

<Other processes>
Examples of other steps include a pretreatment step, a posttreatment step, and a drying step. In the pretreatment step, the pretreatment liquid is applied to the recording medium 203 before image formation by the pretreatment unit 302. In the post-treatment step, the post-treatment liquid is applied to the recording medium 203 after the image formation by the post-treatment unit 305. In the post-processing step of one embodiment, it is applied only to a specific part of the image forming region of the recording medium. The coating amount may be appropriately changed according to the color of the ink forming the image, and preferably the coating amount and the coating method may be changed according to the type and resolution of the recording medium. The method of applying the post-treatment liquid is not particularly limited, and various methods are selected depending on the type of the post-treatment liquid. Can be preferably used. Among these, the same method as the method of ejecting ink is preferable from the viewpoint of the apparatus configuration and the storage stability of the post-treatment liquid. The post-treatment step is a step of applying a post-treatment liquid containing a transparent resin to the formed image surface so that the amount of dry adhesion is 0.5 g / m ² or more and 10 g / m ^{2 or less to form a protective layer.} Is. The drying steps include a step of drying the pretreatment liquid in the pretreatment liquid drying unit 303 and a recording medium 203 to which the ink or the posttreatment liquid is applied in the posttreatment liquid drying unit 306. Including the step of drying.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Preparation Example 1 of Pigment Dispersion)
<Preparation of pigment dispersion PD-1>
Pigment Red 57: 1 (manufactured by Dainichiseika Kogyo Co., Ltd., Seika First), 20 mmol of the compound of the following structural formula (1), and 200 mL of ion-exchanged high pure water are mixed with a Silverson mixer (6,000 rpm) in a room temperature environment. , A slurry was obtained. If the pH of the resulting slurry was higher than 4, 20 mmol of nitric acid was added. After 30 minutes, sodium nitrite (20 mmol) dissolved in a small amount of ion-exchanged hyperpure water was slowly added to the mixture. Further, the mixture was heated to 60 ° C. with stirring and reacted for 1 hour. Then, after adjusting the pH of the mixture to 10 with an aqueous NaOH solution, the mixture was stirred for 30 minutes, ultrafiltration was performed by an diafiltration membrane using ion-exchanged high pure water, and ultrasonic dispersion was further performed to perform magenta pigment having a pigment concentration of 15% by mass. A dispersion was obtained.

(Preparation Examples 2 to 17 of Pigment Dispersion)
20 g of Pigment Red 57: 1 in Preparation Example 1 of the pigment dispersion was changed to 20 g of the components shown in Table 1 below, and PD-2, PD-6, PD-14, and PD-16 were given the structural formula (1). Pigment dispersions PD-2 to PD-17 having a pigment concentration of 15% by mass were obtained in the same manner as in Preparation Example 1 of the pigment dispersion except that the compound of the above was not added. The numerical value in Table 1 is the blending amount (g). Further, "PR", "PB", and "PY" in Table 1 indicate Pigment Red, Pigment Blue, and Pigment Yellow, respectively.

In Table 1, the product names of the ingredients and the names of the manufacturing companies are as follows.
(Magenta pigment)
・ Pigment Red 57: 1 (manufactured by Dainichiseika Kogyo Co., Ltd., azo pigment, Seika First)
・ Pigment Red 52: 1 (Azo pigment manufactured by Sun Chemical corp., Subrite 52: 1)
・ Pigment Red 146 (Azo pigment manufactured by Sun Chemical Corp., Subrite 146)
・ Pigment Red 53: 1 (Azo pigment manufactured by Sun Chemical Corp., Subrite 53: 1)
・ Pigment Red 48: 1 (Azo pigment manufactured by Sun Chemical Corp., Subrite 48: 1)
・ Pigment Red 122 (manufactured by Clariant Japan Co., Ltd., quinacridone pigment, toner magenta EO02)
・ Pigment Red 209 (DIC Corporation, Quinacridone Pigment, FATOGEN Super Red 209 228-6736)
(Cyan pigment)
・ Pigment Blue 15: 1 (manufactured by Dainichiseika Kogyo Co., Ltd., phthalocyanine pigment, chromofine blue)
・ Pigment Blue 15: 3 (manufactured by Dainichiseika Kogyo Co., Ltd., phthalocyanine pigment, chromofine blue)
(Yellow pigment)
・ Pigment Yellow 12 (manufactured by Dainichiseika Kogyo Co., Ltd., azo pigment, Seika First)
・ Pigment Yellow 13 (manufactured by Dainichiseika Kogyo Co., Ltd., azo pigment, Seika First)

(Ink Preparation Example 1)
<Preparation of ink 1>
Table 2 shows 15.0% by mass of the pigment dispersion, propylene glycol (manufactured by ADEKA Co., Ltd., 1.2-propanediol, trade name: industrial propylene glycol) 27.0% by mass, 1,2-hexanediol (1,2-hexanediol). Tokyo Kasei Kogyo Co., Ltd., trade name: 1.2-hexanediol) 6.0% by mass, urethane resin particles (Takelac W6110, Mitsui Chemicals Co., Ltd., glass transition temperature: -20 ° C) 2.3% by mass, Acrylic resin particles (Cymac US480, manufactured by Toa Synthetic Co., Ltd.) 7.7% by mass, nonionic surfactant (trade name: Surfinol 104, manufactured by Air Product and Chemicals, Inc) 2.0% by mass, and the total The remaining amount of ion-exchanged high pure water is added so as to be 100% by mass, and the mixture is mixed and stirred, and then filtered through a membrane filter (trade name: DISMIC-25cs, manufactured by Advantech) having an average pore size of 0.8 μm to obtain ink 1. It was.

(Ink Preparation Examples 2 to 24)
<Preparation of inks 2 to 24>
Inks 2 to 24 were obtained in the same manner as in Ink Preparation Example 1 except that the components in Ink Preparation Example 1 were changed to the compositions shown in Table 2. In addition, each numerical value in Table 2 shows a compounding amount (mass%).

In Table 2, the product names and manufacturing company names of each component are as follows.
-Organic solvent-
-Propylene glycol: manufactured by ADEKA Co., Ltd., 1.2-propanediol, trade name: industrial propylene glycol, 1,2-hexanediol: manufactured by Tokyo Kasei Kogyo Co., Ltd., trade name: 1.2-hexanediol, diethylene glycol: Made by Mitsubishi Chemical Industries, Ltd., Product name: Diethylene glycol / glycerin: Made by Wako Pure Chemical Industries, Ltd., Product name: Glycerin-resin-
Acrylic resin particles: manufactured by Toagosei Co., Ltd., trade name: Cymac US480
Urethane resin particles: Mitsui Chemicals, Inc., trade name: Takelac W6110, glass transition temperature (Tg): -20 ° C
-Surfactant-
-Nonionic surfactant: Air Product and Chemicals, Inc., trade name: Surfinol 104

(Example of black ink preparation)
<Adjustment of black ink>
Black pigment (Nipex160 manufactured by Degussa) 5.0% by mass, propylene glycol (made by ADEKA Co., Ltd., 1.2-propanediol, trade name: industrial propylene glycol) 15.0% by mass, 1,2-hexanediol ( Made by Tokyo Kasei Kogyo Co., Ltd., trade name: 1.2-hexanediol) 5.0% by mass, urethane resin particles (Takelac W6110, manufactured by Mitsui Chemicals Co., Ltd., glass transition temperature: -20 ° C) 2.2% by mass, Acrylic resin particles (Cymac US480, manufactured by Toa Synthetic Co., Ltd.) 2.8% by mass, nonionic surfactant (trade name: Surfinol 104, Air Product and Chemicals, manufactured by Inc.) 2.0% by mass, and the total The remaining amount of ion-exchanged water is added so as to be 100% by mass, and the mixture is mixed and stirred, and then filtered with a membrane filter (trade name: DISMIC-25cs, manufactured by Advantech) having an average pore size of 0.8 μm to obtain black ink. It was.

(Tack force)
Among the adjusted inks, the tack force of the ink film of magenta inks (inks 1 to 20) was measured using an atomic force microscope (AFM, SPM-9500J3, manufactured by Shimadzu Corporation). At this time, a cantilever provided with spherical silicone oxide (spring constant of the cantilever: 0.29 N / m) was used as the probe. The image used for the measurement uses paper (trade name: Lumi Art Gloss 90gsm or 200gsm, manufactured by Stora Enso) and uses an inkjet printing system (RICOH Pro VC60000, manufactured by Ricoh Co., Ltd.) to achieve a resolution of 1200 dpi and a printing speed. A solid image recorded at 50 m / min was used. The results are shown in Table 3. In Table 3, the unit of tack force is nN.

(Examples 1 to 24 and Comparative Examples 1 to 9)
[Image formation]
Images were recorded on both sides of a recording medium by an inkjet printing system (RICOH Pro VC60000, manufactured by Ricoh Co., Ltd.) using the obtained inks 1 to 24 in the combinations shown in Table 3, and the images were evaluated. However, in Comparative Example 9, IPSIO GX5500 (manufactured by Ricoh Co., Ltd.) was used as an inkjet printing system, and after image recording, it was dried at 100 ° C. for 1 minute and then left at room temperature for 24 hours. The IPSIO GX5500 is a serial type printer, and Comparative Example 9 does not execute the winding process. As the recording medium, the paper shown in Table 3 below (roll paper except for Comparative Example 9) is used, and magenta, red (* magenta and yellow are used), and blue according to the image processing of the model used at a resolution of 1,200 dpi. (* Magenta and cyan are used) Solid images of each of the three colors were recorded. The method for forming a solid image for each of the three colors magenta, red (* using magenta and yellow), and blue (* using magenta and cyan) is as follows. The solid image of magenta was created using one color of magenta ink. The red solid image is created by creating a magenta solid image in the same manner as the magenta solid image above, and then overlaying the magenta solid image on top of the yellow solid image using yellow ink. did. The blue solid image was created by creating a cyan solid image using cyan ink, then superimposing it on the cyan solid image, and then superimposing the magenta solid image using magenta ink.

A Rewinding module RW6 (manufactured by Hunkeler) was used as the winding device other than Comparative Example 9. At that time, the winding tension was varied, and as shown in Table 3 below, the pressure applied to the image was changed to evaluate "blocking resistance" and "rubbing resistance". The unit of pressure in Table 3 is kg / cm ² . Next, after the recording is completed once, the paper is set in the image forming apparatus again, and the magenta, yellow, and cyan inks used in the first ink application step are changed to the second ink (black ink). A solid image was recorded at a resolution of 200 dpi, and "positional deviation at the time of applying the second ink" was evaluated. The results are shown in Table 3.

FIG. 7 is a perspective view showing an example of continuous paper. FIG. 8 is a side view of the continuous paper of FIG. 7. The pressure applied to the image was measured using a device name: surface pressure distribution measurement system I-SCAN (manufactured by Nitta Corporation) and I-SCAN # 5027 (manufactured by Nitta Corporation) as a sensor sheet. As shown in FIGS. 7 and 8, the continuous paper 12 was wound in a roll shape, and the sensor sheet 13 for measuring the pressure was installed at a position 20 cm from the outside of the paper tube 11 having the cavity 10. By installing the sensor sheet 13 at three points whose positions are changed in the width direction of the continuous paper 12, three measurement points are provided. After that, the continuous winding of the continuous paper 12 was continued, the pressure at the stage where the 10 cm papers were overlapped when viewed from the three measurement points was measured, and the average value of the pressures at the three points was taken as the pressure applied to the image. ..

(saturation)
The magenta, red, and blue solid parts of each of the formed images were measured for brightness using a reflective color spectrophotometric densitometer (manufactured by X-Rite), and the obtained values of a * and b * were used. Saturation C * = ((a *) ² + (b *) i ² ) ^1/2 was calculated. Calculate the ratio k = C * / C * 0 of the measured saturation C * to the saturation value C * 0 of the standard color (Japan color ver.2) of each magenta, red, or blue color, and then calculate the following. It was evaluated according to the evaluation criteria of. B or higher is practical. The results are shown in Table 3.
-Evaluation criteria-
A: 1.1> k ≧ 1.0
B: 1.0> k ≧ 0.9
C: 0.9> k

(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. B or higher is practical. The results are shown in Table 3.
-Evaluation criteria-
A: No image transfer B: Light sticking is felt when peeling off, but no image transfer C: Image transfer

(Scratch resistance)
For each of the obtained images, rub the images 20 times using paper (Lumi Art Gloss 90gsm) cut into 1.2 mm squares, and use a reflective color spectrophotometric densitometer (manufactured by X-Rite) to transfer to paper. The ink adhesion stain 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. B or higher is practical. The results are shown in Table 3.
-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

(Mottled)
Each of the obtained images was visually observed, and mottle was evaluated based on the following evaluation criteria. B or higher is practical. The results are shown in Table 3.
-Evaluation criteria-
A: The graininess of the image is noticeable B: The graininess of the image is slightly seen C: The graininess of the image is not seen

(Position shift)
Each of the obtained images was visually observed, and the positional deviation was evaluated based on the following evaluation criteria. B or higher is practical.
〔Evaluation criteria〕
A: Positional deviation is noticeable B: Positional deviation is slightly seen C: Positional deviation is not seen

In Table 3, the product names and manufacturing company names of the recording image media are as follows.
・ LAG130: Lumi Art Gloss 130gsm, manufactured by Stora Enso ・ OK top: OK top coat + 127.9gsm, manufactured by Oji Paper Co., Ltd. ・ UPM: UPM Finesse gloss 130gsm, manufactured by UPM ・ MCS: Magno ClassicSil -GP: G-Print 90gsm, manufactured by Arctic Paper

300 Inkjet recording device 301 Recording medium transport unit 302 Pretreatment unit 303 Pretreatment liquid drying unit 304 Image forming unit 305 Post-processing unit 306 Post-processing liquid drying unit 307 Paper feeding device 308 Winding device

Japanese Unexamined Patent Publication No. 2013-248883

Claims (12)

The first ink application step of applying one or more inks including magenta ink to a recording medium to form an image, and
It has a winding step of winding a recording medium to which one or more inks are applied.
The ink contains water, an organic solvent, a resin, and a coloring material.
The resin is selected from urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Contains at least one resin
The content of the resin is 1% by mass or more and 30% by mass or less with respect to the total amount of ink.
The magenta ink contains an azo pigment as the coloring material and contains an azo pigment.
The tack force of the ink film formed by the magenta ink is 80 nN or more and 110 nN or less.
The tack force (F) of the ink film formed by the magenta ink is determined by using an atomic force microscope (AFM, SPM-9500J3, manufactured by Shimadzu Corporation) at a temperature of 23 ° C., a humidity of 35% RH, and a probe diameter of 3. .5 μm, measurement mode: Force curve measurement, measured under the condition of measurement frequency 1 Hz, 1200 dpi by inkjet printing system (RICOH Pro VC60000, manufactured by Ricoh Co., Ltd.) on paper (Lumi Art Gloss 90 gsm or 200 gsm, manufactured by Stora Enso). A cantilever equipped with a spherical silicone oxide as a probe is brought into contact with a solid image recorded at a resolution and a printing speed of 50 m / min, the probe is pulled up after pushing in 100 nm, and the cantilever bends when moving away from the image. An image forming method that is a value (F = kx) obtained by multiplying the amount of displacement (x) by the spring constant (k = 0.29 N / m) of the cantilever. The image forming method according to claim 1, wherein pressure is applied to the image in the winding step. The pressure, 3.5 kg / cm ² or more 8.0 kg / cm ² or less image forming method according to claim 2. The invention according to any one of claims 1 to 3, further comprising a second ink applying step of applying ink to the surface of the recording medium to which the ink is applied to form an image after the winding step. Image formation method. The image forming method according to any one of claims 1 to 4, wherein the tack force is 85 nN or more and 100 nN or less. The image forming method according to any one of claims 1 to 5, wherein the magenta ink contains at least one selected from the group of PR57: 1, PR52: 1, and PR146 as the azo pigment. The one or more inks include the magenta ink, cyan ink, and yellow ink.
The cyan ink contains a phthalocyanine pigment and contains
The image forming method according to any one of claims 1 to 6, wherein the yellow ink contains an azo pigment. The image forming method according to any one of claims 1 to 7, wherein the ink contains urethane resin particles. Any of claims 1 to 8 in which the ratio of the saturation of the magenta, red, and blue ink films formed by the above-mentioned one or more inks to the saturation of the standard color of Japan color ver.2 is 0.9 or more. The image forming method according to item 1. An accommodating means for accommodating one or more inks including magenta ink,
A first ink applying means for forming an image by applying one or more inks to a recording medium,
It has a winding means for winding a recording medium to which one or more inks are applied.
The ink contains water, an organic solvent, a resin, and a coloring material.
The resin is selected from urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Contains at least one resin
The content of the resin is 1% by mass or more and 30% by mass or less with respect to the total amount of ink.
The magenta ink contains an azo pigment as the coloring material and contains an azo pigment.
The tack force of the ink film formed by the magenta ink is 80 nN or more and 110 nN or less.
The tack force (F) of the ink film formed by the magenta ink is determined by using an atomic force microscope (AFM, SPM-9500J3, manufactured by Shimadzu Corporation) at a temperature of 23 ° C., a humidity of 35% RH, and a probe diameter of 3. .5 μm, measurement mode: Force curve measurement, measured under the condition of measurement frequency 1 Hz, 1200 dpi by inkjet printing system (RICOH Pro VC60000, manufactured by Ricoh Co., Ltd.) on paper (Lumi Art Gloss 90 gsm or 200 gsm, manufactured by Stora Enso). A cantilever equipped with a spherical silicone oxide as a probe is brought into contact with a solid image recorded at a resolution and a printing speed of 50 m / min, the probe is pulled up after pushing in 100 nm, and the cantilever bends when moving away from the image. An image forming apparatus which is a value (F = kx) obtained by multiplying the amount of displacement (x) by the spring constant (k = 0.29 N / m) of the cantilever. An accommodating means for accommodating one or more inks including magenta ink,
A first ink applying means for forming an image by applying one or more inks to a recording medium,
It has a winding means for winding a recording medium to which one or more inks are applied.
The ink contains water, an organic solvent, a resin, and a coloring material.
The resin is selected from urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Contains at least one resin
The content of the resin is 1% by mass or more and 30% by mass or less with respect to the total amount of ink.
The magenta ink contains an azo pigment as the coloring material and contains an azo pigment.
The tack force of the ink film formed by the magenta ink is 80 nN or more and 110 nN or less.
The tack force (F) of the ink film formed by the magenta ink is determined by using an atomic force microscope (AFM, SPM-9500J3, manufactured by Shimadzu Corporation) at a temperature of 23 ° C., a humidity of 35% RH, and a probe diameter of 3. .5 μm, measurement mode: Force curve measurement, measured under the condition of measurement frequency 1 Hz, 1200 dpi by inkjet printing system (RICOH Pro VC60000, manufactured by Ricoh Co., Ltd.) on paper (Lumi Art Gloss 90 gsm or 200 gsm, manufactured by Stora Enso). A cantilever equipped with a spherical silicone oxide as a probe is brought into contact with a solid image recorded at a resolution and a printing speed of 50 m / min, the probe is pulled up after pushing in 100 nm, and the cantilever bends when moving away from the image. An image forming system that is a value (F = kx) obtained by multiplying the amount of displacement (x) by the spring constant (k = 0.29 N / m) of the cantilever. The first ink application step of applying one or more inks including magenta ink to a recording medium to form an image, and
It has a winding step of winding a recording medium to which one or more inks are applied.
The ink contains water, an organic solvent, a resin, and a coloring material.
The resin is selected from urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Contains at least one resin
The content of the resin is 1% by mass or more and 30% by mass or less with respect to the total amount of ink.
The magenta ink contains an azo pigment as the coloring material and contains an azo pigment.
The tack force of the ink film formed by the magenta ink is 80 nN or more and 110 nN or less.
The tack force (F) of the ink film formed by the magenta ink is determined by using an atomic force microscope (AFM, SPM-9500J3, manufactured by Shimadzu Corporation) at a temperature of 23 ° C., a humidity of 35% RH, and a probe diameter of 3. .5 μm, measurement mode: Force curve measurement, measured under the condition of measurement frequency 1 Hz, 1200 dpi by inkjet printing system (RICOH Pro VC60000, manufactured by Ricoh Co., Ltd.) on paper (Lumi Art Gloss 90 gsm or 200 gsm, manufactured by Stora Enso). A cantilever equipped with a spherical silicone oxide as a probe is brought into contact with a solid image recorded at a resolution and a printing speed of 50 m / min, the probe is pulled up after pushing in 100 nm, and the cantilever bends when moving away from the image. A method for producing an image forming product, which is a value (F = kx) obtained by multiplying the amount of displacement (x) by the spring constant (k = 0.29 N / m) of the cantilever.