JP2002187341A - Ink jet image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet image forming method, with which an ink jet recording image having no difference between the gloss of a non-printing part and the gloss of a printing part and having a uniform feeling and an excellent gloss is obtained. SOLUTION: In this ink jet image forming method, after a pigment ink is discharged and adhered in the fashion of an image by an ink jet system onto an ink jet recording medium having a pigment ink accepting layer including a thermoplastic resin fine particle on the outermost side of a support and a pigment ink solvent absorbing layer adjacent to the pigment ink accepting layer, heating and pressurizing are simultaneously applied with two rollers, the average surface roughness of the roller contacting with an image surface between which is 100 nm or less, at a simultaneous heating and pressurizing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet image forming method, and more particularly, to an ink-jet image forming method capable of obtaining an ink-jet recorded image having excellent gloss with no difference in gloss between an unprinted portion and a printed portion. About.

[0002]

2. Description of the Related Art Ink jet recording is a technique in which fine droplets of ink are caused to fly according to various operating principles and adhere to an ink jet recording medium (hereinafter, simply referred to as a recording medium).
It is used to form images such as images and characters, but has the advantages of relatively high speed, low noise, and easy multicoloring. In addition, high image quality approaching silver halide photography of ink-jet printing using dye ink and cost reduction of the apparatus due to recent technological progress have further accelerated the spread thereof.

A dye used for a dye ink in ink-jet printing is mainly soluble in a solvent, and a dye molecule is colored in a molecular state or a cluster state. Therefore, since the environment of each molecule is similar, its absorption spectrum is sharp, and shows high purity and vivid coloration. Further, these dyes do not have particle properties and, as a result, do not generate scattered light or reflected light, so that they have high transparency and a clear hue.

[0004] However, when the dye molecules are destroyed by a photochemical reaction or the like, the decrease in the number of molecules is directly reflected on the coloring density, so that there is a disadvantage that light resistance is poor. As described above, although the ink jet recorded image using the dye ink has high image quality, the image quality is largely deteriorated due to storage over time, and a technology that surpasses silver halide photography in terms of image storability has not yet appeared. Met.

[0005] On the other hand, a technique of using a pigment ink using a pigment having good light resistance as a colorant as a colorant as an ink for an application requiring an image resistant to fading due to light with respect to the dye ink described above, for inkjet printing. There is. The pigment is insoluble in the solvent, and the dye molecules form particles and contribute to coloring in a state of being dispersed in the solvent. Even if the surface molecules are destroyed by photochemical reaction etc., there is a new dye molecule layer underneath, so the decrease in apparent coloring power is small, and it has the characteristics of excellent image storability, but it is a particle Due to the influence of the scattered light and the reflected light resulting from this, there was a problem that the glossiness was remarkably deteriorated.

JP-A-11-208097 discloses a technique in which after recording an image with a pigment ink containing no dispersant on a recording medium having a thermoplastic resin layer as the outermost layer, pigment particles are moved into the thermoplastic resin layer. Have been. That is,
After the pigment ink adheres to the surface of the recording medium, the pigment particles of the pigment ink are present on the surface of the thermoplastic resin layer, and the solvent component is absorbed by each layer constituting the recording medium. Subsequently, by moving the pigment particles into the thermoplastic resin layer, the floating of the printed portion specific to the pigment ink with respect to the unprinted portion is eliminated to some extent, but the effect is still insufficient, and it is particularly noticeable. However, the gloss difference between the unprinted area and the printed area cannot be completely eliminated, which is a problem.

Japanese Patent Application Laid-Open No. 2000-203008 discloses a technique of transferring a roll surface shape between two pressure rollers after a heating step of a thermoplastic resin particle layer. However, even with this technique, the gloss difference between the unprinted area and the printed area cannot be completely eliminated, which is a problem.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an ink jet recorded image having excellent gloss with no difference in gloss between an unprinted portion and a printed portion. To provide an ink-jet image forming method capable of obtaining the following.

[0009]

The above object of the present invention is achieved by the following constitution. 1. The pigment ink is ejected imagewise by an inkjet method onto an inkjet recording medium having a pigment ink receiving layer containing thermoplastic resin fine particles on the outermost surface of the support and a pigment ink solvent absorbing layer adjacent to the pigment ink receiving layer. And heating and pressurizing are performed simultaneously using two facing rollers having an average surface roughness of 100 nm or less on the roller in contact with the image surface in the simultaneous heating and pressurizing step. Image forming method.

[0010] 2. The pigment ink is ejected imagewise by an inkjet method onto an inkjet recording medium having a pigment ink receiving layer containing thermoplastic resin fine particles on the outermost surface of the support and a pigment ink solvent absorbing layer adjacent to the pigment ink receiving layer. After the heating and pressurizing, heating and pressurizing are performed simultaneously using two facing rollers having an average surface roughness of 100 nm or less on the roller in contact with the image surface in a simultaneous heating and pressurizing process. Performing an inkjet image forming method.

3. 2. The ink-jet image forming method according to 1, wherein the roller surface temperature of the roller that simultaneously performs heating and pressurization is a temperature equal to or higher than the glass transition point of the thermoplastic resin fine particles.

4. 3. The ink-jet image forming method according to 2, wherein both the heating temperature in the heating step and the roller surface temperature of the roller that performs heating and pressurization simultaneously are temperatures equal to or higher than the glass transition point of the thermoplastic resin fine particles.

5. The inkjet image forming method according to any one of claims 1 to 4, wherein at least one selected from a pigment ink receiving layer and a pigment ink contains a silicon emulsion or a metal stearate.

6. The inkjet image forming method according to any one of claims 1 to 5, wherein the pigment ink contains thermoplastic resin fine particles having a lower glass transition point than the thermoplastic resin fine particles contained in the pigment ink receiving layer.

Hereinafter, the present invention will be described in detail. As the thermoplastic resin fine particles contained in the pigment ink receiving layer of the present invention, for example, polycarbonate, polyacrylonitrile, polystyrene, polyacrylic acid, polymethacrylic acid, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, Fine particles such as polyamides, polyethers and copolymers thereof are exemplified, and a latex of these resin fine particles is preferably used. Points to consider when selecting a thermoplastic resin include pigment ink receptivity, gloss after fixing by heating and pressing, and image fastness.

Regarding the pigment ink receptivity, if the thermoplastic fine particles are too small, the separation of the pigment particles from the ink solvent in the pigment ink and the ink solvent will be slowed, causing a substantial reduction in the absorption rate. On the other hand, if it is too large, it is not preferred from the viewpoints of adhesiveness to the adjacent pigment ink solvent absorbing layer when coated on the support and film strength after coating and drying. For this reason, the particle size of the thermoplastic resin fine particles contained in the pigment ink receiving layer of the present invention is preferably 0.05 to 10 μm, more preferably 0.1 to 5 μm.

The criteria for selecting the thermoplastic resin fine particles contained in the pigment ink receiving layer of the present invention include a glass transition point Tg. When Tg is extremely low,
For example, the coating / drying temperature at the time of production of the recording medium is already higher than Tg, and the voids of the thermoplastic resin fine particles through which the pigment ink solvent permeates disappear. In addition, when the Tg is extremely high, a fixing operation at a high temperature is required to perform melt film fixing after inkjet recording with a pigment ink,
Problems such as the load on the apparatus and the thermal stability of the support are problematic. Therefore, the Tg of the thermoplastic resin particles contained in the pigment ink receiving layer of the present invention is preferably 50 to 150 ° C.

The pigment ink solvent absorbing layer of the present invention is a layer that absorbs the solvent of the pigment ink and preferably has voids formed in the layer, and the voids absorb various inorganic solid fine particles in the pigment ink solvent. It is formed by being contained in a layer. Examples of the inorganic solid fine particles used for the above purpose include, for example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, sulfide Zinc, zinc carbonate, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, magnesium hydroxide, etc. White inorganic pigment fine particles.
From the viewpoints that a high-density image is formed, a clear image can be recorded, and that it can be manufactured at low cost, the inorganic solid fine particles include fine particle silica, colloidal silica, and alumina or alumina water synthesized by a gas phase method. It is preferable to use inorganic solid fine particles selected from the sum. Alumina or alumina hydrate may be crystalline or amorphous, and may have any shape such as irregular shaped particles, spherical particles, and acicular particles. At present, fine particle silica synthesized by such a gas phase method is commercially available, and various types of commercially available fine particle silica include Aerosil manufactured by Nippon Aerosil Co., Ltd. In order to obtain the effects of the present invention, the particle size of the inorganic solid fine particles is not particularly limited, but is preferably 100 nm or less, and the particle size most suitable for forming the voids differs depending on the compound. In the case of silica, the average particle size of the primary particles of the inorganic solid fine particles dispersed in the state of the primary particles (the particle size in the state of the dispersion before application) is most preferably 4 to 20 nm.

The average particle size of the inorganic solid fine particles can be determined by observing the particles themselves or the particles that have appeared on the cross section or surface of the void-type pigment ink solvent absorbing layer with an electron microscope, and calculating the particle size of 100 arbitrary particles. It is obtained as a simple average (number average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to its projected area.

The total amount of voids (void volume) in the pigment ink receiving layer and the pigment ink solvent absorbing layer containing the thermoplastic resin fine particles of the recording medium of the present invention is preferably 20 ml or more per 1 m ² of the recording medium. 20 void volume
When the amount is less than ml / m ² , the ink absorbency is good when the amount of ink at the time of printing is small, but when the amount of ink is large, the ink is not completely absorbed, thereby deteriorating the image quality or delaying the drying property. Problems are more likely to occur. The upper limit of the void volume is not particularly limited, but it is necessary that the thickness of the void-type ink absorbing layer be approximately 50 μm or less in order not to deteriorate the physical properties of the film such as cracks. The void volume is preferably 40 ml / m ² or less.

In the present invention, the void volume is determined according to J. Org. TAP
PI paper pulp test method No. 51-87 Measured according to the method described in Liquid Absorbency Test Method for Paper and Paperboard (Bristow Method).
² ). In the above measurement method, pure water (ion-exchanged water) is used for the measurement, but a water-soluble dye of less than 2% may be contained in order to easily determine the measurement area.

As the support of the present invention, supports conventionally used for ink jet recording media, for example, paper supports such as plain paper, art paper, coated paper and cast-coated paper, plastic supports, and both sides can be used. A paper support coated with polyolefin, a composite support in which these are laminated, and the like can be used.

The ink jet recording medium of the present invention has a pigment ink solvent absorbing layer having an ability to absorb the ink solvent of the pigment ink, in addition to the pigment ink receiving layer. The pigment ink solvent absorbing layer has a void inside the layer, and the void is mainly formed by a hydrophilic binder and inorganic solid fine particles or organic solid fine particles. Prior to the application of the pigment ink solvent-absorbing layer, the support is preferably subjected to a corona discharge treatment, an undercoating treatment, or the like, for the purpose of increasing the adhesive strength between the support and the pigment-ink solvent-absorbing layer. Furthermore, the support of the present invention does not necessarily need to be colorless, and may be a colored support.

As the support of the present invention, a paper support in which both sides of a base paper support are laminated with polyethylene is used, since the recorded image is close to the photographic quality, and a high-quality image can be obtained at low cost. Particularly preferred. Such a paper support laminated with polyethylene is described below.

The base paper used for the paper support is made from wood pulp as a main raw material and, if necessary, using synthetic pulp such as polypropylene or synthetic fiber such as nylon or polyester in addition to wood pulp. As wood pulp, LBKP, LBSP, NBKP, NBSP, LD
Any of P, NDP, LUKP, and NUKP can be used, but LBKP, NBSP, and LBS containing a large amount of short fibers
It is preferable to use more P, NDP, and LDP.
However, the ratio of LBSP and / or LDP is 10% by mass.
As mentioned above, 70 mass% or less is preferable.

As the pulp, a chemical pulp containing a small amount of impurities (sulfate pulp or sulfite pulp) is preferably used, and pulp having improved whiteness by a bleaching treatment is also useful. Base paper contains sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc, and titanium oxide; paper strength agents such as starch, polyacrylamide, and polyvinyl alcohol; fluorescent whitening agents; and polyethylene glycols. , Etc., a water retention agent, a dispersant, a softening agent such as quaternary ammonium, and the like can be appropriately added.

The freeness of pulp used for papermaking is determined by CSF
The fiber length after beating is preferably 30 to 70% when the sum of the mass% of the remaining 24 mesh and the mass% of the remaining 42 mesh specified in JIS-P-8207 is 30 to 70%. preferable. In addition, it is preferable that the mass% of 4 mesh residue is 20 mass% or less. The basis weight of the base paper is preferably 30 to 250 g / m ² , particularly 50 to 20 g / m ^2.
0 g / m ² is preferred. Base paper thickness is 40 ~ 250μm
Is preferred. The base paper may be calendered at the papermaking stage or after papermaking to provide high smoothness. The base paper density is generally 0.7 to 1.2 (JIS-P-8118). Further, the rigidity of the base paper is preferably from 20 to 200 g under the conditions specified in JIS-P-8143. A surface sizing agent may be applied to the surface of the base paper, and the same sizing agent as can be added to the base paper can be used as the surface sizing agent. The pH of the base paper is preferably 5 to 9 when measured by a hot water extraction method specified in JIS-P-8113.

The polyethylene covering the front and back surfaces of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but other linear low-density polyethylene (LLDPE) and polypropylene are also available. Department can be used. Polyethylene-coated paper can be used as glossy paper.Also, when polyethylene is melted and extruded onto the base paper surface, a so-called molding process is performed to coat the matte surface or silk surface as obtained with ordinary photographic printing paper. Those formed can also be used in the present invention. The amount of polyethylene used on the front and back of the base paper is selected so as to optimize the curl under low and high humidity after providing the ink solvent absorbing layer and the back layer. 20-40μ layer
m, the back layer side is in the range of 10 to 30 μm.

Further, the paper support coated with the polyethylene preferably has the following properties.

1. Tensile strength: JIS-P-8113
2-30 kg in the vertical direction and 1 in the horizontal direction with the strength specified by
1. It is preferably 20 kg. Tear strength: 10 to 200 g in the vertical direction and 20 to 200 g in the horizontal direction according to the method specified in JIS-P-8116.
Is preferred. Compression modulus ≧ 98.1 MPa 4. Opacity: 80% or more, particularly preferably 85 to 98%, as measured by the method specified in JIS-P-8138. Whiteness: L ^* defined by JIS-Z-8729,
a ^* and b ^* are L ^* = 80 to 95, a ^* = − 3 to +5, b ^* =
It is preferably −6 to +2. 6. Clark stiffness: A support having a Clark stiffness of 50 to 300 cm2 / 100 in the transport direction of the recording paper is preferable. Moisture in base paper: preferably 4 to 100% by mass with respect to the middle paper.

The method of applying various constituent layers, such as a pigment ink-receiving layer, a pigment ink solvent-absorbing layer, and an undercoat layer, of the recording medium of the present invention, which are appropriately provided as necessary, onto a support may be selected from known methods. You can choose to do it. As a preferable method, there is a method in which a coating solution constituting each layer is applied on a support and dried to obtain a recording medium.

The coating method includes a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, and an extrusion coating method using a hopper described in US Pat. No. 2,681,294. It is preferably used. In applying the ink jet recording medium of the present invention, a thickener may be used to improve applicability.

In the present invention, as a heating method after image recording in which a pigment ink is ejected and adhered imagewise to an ink jet recording medium by an ink jet method, either a method using a heater or the like or a method using a heater to blow heated air is used. be able to. The heating temperature must be equal to or higher than the glass transition point Tg of the thermoplastic resin particles contained in the pigment ink receiving layer provided on the recording medium.
The glass transition point Tg is a value unique to the thermoplastic resin of the thermoplastic resin particles to be employed, and the heating temperature varies depending on the type of the resin. The upper limit of the heating temperature is usually about 150 ° C. from the viewpoint of the load on the apparatus and the thermal stability of the paper support.

The heating temperature in the heating and pressurizing simultaneous step (heating and pressurizing simultaneously) of the first aspect of the present invention is the glass transition point T of the thermoplastic resin fine particles as described above.
It is preferable that the temperature is not less than g and not more than 150 ° C.

As for the relationship between the temperatures in the heating step and the simultaneous heating and pressing step in the second aspect of the present invention, the temperature in the simultaneous heating and pressing step is preferably equal to or lower than the heating step temperature. . If the temperature of the simultaneous heating and pressurizing step is higher than the temperature of the heating step, the melting and softening of the thermoplastic resin fine particles excessively progresses, which may easily cause a jam sticking to the roller used in the simultaneous heating and pressurizing step. Not preferred.

Among the rollers used in the simultaneous heating and pressurizing step of the present invention, the average surface roughness of the roller in contact with the image surface is as follows.
It can be measured using an STPLUS non-contact three-dimensional micro surface shape measurement system. Using the same measuring device,
It is preferable because the average surface roughness can be measured after correcting the curvature of the roller. ) From the viewpoint of obtaining the effects of the present invention, 100
nm or less. This is an essential condition when it is assumed that pigment ink is used as a color material used for image recording. Preferably it is 20 to 90 nm, more preferably 40 to 70 nm. If it is less than 20 nm, the offset property may be deteriorated.

When a dye is used as the coloring material of the ink, the ink passes through the ink receiving layer containing the thermoplastic resin fine particles, which is the uppermost layer, and moves to the adjacent ink solvent absorbing layer containing the inorganic solid fine particles. I do. In this case, when the heating / pressing simultaneous treatment or the heating / heating / pressing simultaneous step treatment is performed, the coloring material (dye) does not exist on the ink receiving layer containing the thermoplastic resin fine particles, and only the thermoplastic resin fine particles are used. As the ink receiving layer is melt-film-fixed, an image having excellent surface smoothness can be easily obtained. On the other hand, in the case of pigment ink, the coloring material (pigment) of the pigment ink remains on the ink receiving layer containing the thermoplastic resin fine particles. Moved into the layer by pressure, and for the purpose of the present invention to obtain uniformity of the glossiness of the printed portion of the image surface, the unprinted portion, in order to achieve an increase in the surface smoothness of the image surface, It is essential to control the surface condition of the roller on the side in contact with the image surface as described above.

The roller used in the simultaneous heating and pressing step of the present invention is characterized in that it is constituted by a metal roller or a silicon rubber roller. Among them, the metal roller may be made of a general material such as iron or aluminum, and is coated with a tetrafluoroethylene or a polytetrafluoroethylene-perfluoroalkylvinyl ether copolymer or the like for the purpose of improving thermal durability. It may be mirror-finished to improve the smoothness after fixing. The two rollers facing each other deform the rollers by applying pressure between them to form a so-called nip. The nip width is usually 1 to 20 mm, preferably 1.5 to 7 mm. The linear pressure generated between the two rollers is 1 × 10 ^{−5 to} 5 × 10 ^−6.
Pa is preferred.

It is preferable that at least one selected from the pigment ink receiving layer and the pigment ink of the outermost layer of the ink jet recording medium of the present invention contains a silicon emulsion or a metal stearate.

In order to improve the releasability of the recording medium from the rollers when the recording medium on which the image has been fixed through the simultaneous heating and pressing process is discharged from the two facing rollers which are pressure rollers. It is preferable to add a silicon emulsion or a metal stearate-containing solution in the pigment ink receiving layer containing the thermoplastic resin fine particles as the outermost layer of the medium and / or in the pigment ink. Examples of the silicon emulsion include KM740, KM780, KM78
6, KM788, KM860, KM862 (all manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be used. Examples of the metal stearate include zinc stearate having releasability, such as R-053D and R-1.
004 and R-070U (both manufactured by Nissin Chemical Laboratory) can be used. The addition amount is 0.5 to 5 with respect to the solid content of the thermoplastic resin fine particles (latex).
About mass% is preferable. In addition, when adding to ink, the same amount (volume) of addition to ink volume
Is preferable, but it is premised on the amount of addition that does not impair the dischargeability from the head.

When a recording medium containing a release agent in a pigment ink receiving layer containing thermoplastic resin fine particles in the outermost layer of the recording medium is treated in a simultaneous heating and pressurizing step, the pigment ink in the pigment ink receiving layer Since the image area to which is applied is coated with the pigment ink, the release agent becomes difficult to function. Therefore, it is preferable to add the release agent to the pigment ink.

The pigment ink of the present invention preferably contains a surfactant in order to improve the dispersion stability of the pigment. Surfactants preferably used in the pigment ink of the present invention include dialkyl sulfosuccinates, alkyl naphthalene sulfonates, anionic surfactants such as fatty acid salts, polyoxyethylene alkyl ethers,
Nonionic surfactants such as polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. In particular, an anionic surfactant and a nonionic surfactant can be preferably used.

As the pigment used in the pigment ink of the present invention, conventionally known organic and inorganic pigments can be used. For example, azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc .; phthalocyanine pigments, perylene and perylene pigments; Dye lakes such as cyclic pigments, basic dye lakes, and acid dye lakes; organic pigments such as nitro pigments, nitroso pigments, aniline black and daylight fluorescent pigments; and inorganic pigments such as carbon black.

Specific examples of the organic pigment are shown below. Pigments for magenta or red include C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I.
I. Pigment Red 7, C.I. I. Pigment Red 1
5, C.I. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 53:
1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 12
3, C.I. I. Pigment Red 139, C.I. I. Pigment red 144, C.I. I. Pigment Red 149,
C. I. Pigment Red 166, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I.
I. Pigment Red 222 and the like.

Examples of pigments for orange or yellow include C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I. Pigment Yellow 12,
C. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I.
I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I.
Pigment Yellow 138 and the like.

The pigments for green or cyan include:
C. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3,
C. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

The pigment ink of the present invention may contain a pigment dispersant, if necessary. Examples of usable pigment dispersants include higher fatty acid salts, alkyl sulfates, alkyl ester sulfates, alkyl sulfonates, sulfosuccinates, naphthalene sulfonates, alkyl phosphates, and polyoxyalkylene alkyl ether phosphates. ,
Activator such as polyoxyalkylene alkyl phenyl ether, polyoxyethylene polyoxypropylene glycol, glycerin ester, sorbitan ester, polyoxyethylene fatty acid amide, amine oxide, or styrene, styrene derivative, vinyl naphthalene derivative, acrylic acid, acrylic acid derivative , Maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, block copolymers composed of two or more monomers selected from fumaric acid derivatives, etc., and random copolymers and salts thereof. Can be.

In the pigment ink of the present invention, examples of the method for dispersing the pigment include a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer,
Various types such as a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used.

In the pigment ink of the present invention, it is also preferable to use a centrifugal separator or a filter for the purpose of removing coarse particles of the pigment dispersion.

The average particle size of the pigment dispersion used in the pigment ink of the present invention is usually from 10 nm to 200 nm, preferably from 10 nm to 100 nm, more preferably from 10 nm to 50 nm. If the average particle size of the pigment dispersion exceeds 100 nm, the glossiness of the image recorded on the glossy type recording medium tends to deteriorate. When the average particle size of the pigment dispersion is less than 10 nm, the stability of the pigment dispersion is likely to deteriorate, and the storage stability of the ink is likely to deteriorate.

The particle size of the pigment dispersion can be measured by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, a laser Doppler method or the like. In addition, it is also possible to obtain a particle image using a transmission electron microscope on at least 100 particles or more, and to perform a statistical process on the image using image analysis software such as Image-Pro (manufactured by Media Cybernetics). It is possible.

According to the invention of claim 6 of the present invention, it is preferable that “thermoplastic resin fine particles having a lower glass transition point than the thermoplastic resin fine particles contained in the pigment ink receiving layer (hereinafter simply referred to as low Tg).
In the heating step after the pigment ink is ejected and adhered imagewise by an inkjet method onto the pigment ink receiving layer containing the thermoplastic resin fine particles, It starts melting at a lower temperature and acts as a kind of plasticizer for the thermoplastic resin fine particles of the pigment ink receiving layer, so that the heat of the pigment ink receiving layer immediately below the coloring material of the pigment ink ejected and adhered imagewise. The effect of the present invention can be more remarkably exhibited by promoting the melting of the plastic resin fine particles.

The thermoplastic resin particles to be added to the pigment ink of the present invention refer to polymer particles (latex) dispersed in a medium of the pigment ink. Examples of the type of polymer fine particles include, for example, styrene-butadiene copolymer, polystyrene, acrylonitrile-butadiene copolymer, acrylate copolymer, polyurethane,
Latexes such as a silicone-acrylic copolymer and an acrylic-modified fluororesin are available, and among them, acrylic acid ester, polyurethane, and a latex of a silicone-acrylic copolymer are preferable.

As the emulsifier used in the production of the latex, a low molecular weight surfactant is generally used. However, a high molecular weight surfactant (for example, a type having a solubilizing group graft-bonded to a polymer or a surfactant having a low molecular weight) can be used. There is a block polymer type in which a portion having a solubilizing group and an insoluble portion are linked, etc.) can also be used as an emulsifier. Also,
Some latexes are dispersed without emulsifiers by attaching solubilizing groups directly to the central polymer of the latex. Latexes using a high molecular weight surfactant as an emulsifier and latexes not using an emulsifier as described above are called soap-free latex.
The latex used in the present invention is not limited to the type and form of the emulsifier, but it is more preferable to use a soap-free latex having excellent storage stability of the pigment ink.

Further, recently, besides the latex having a uniform central polymer, there is also a core-shell type latex having a different composition at the center portion and the outer edge portion of the polymer particles, and this type of latex is preferably used. it can.

The average particle size of the latex of the thermoplastic resin fine particles added to the pigment ink preferably used in the present invention is preferably 150 nm or less, more preferably 50 nm or less. The average particle diameter of the latex can be easily measured using a commercially available measuring device using a light scattering method or a laser Doppler method.

The solid content of the latex of the thermoplastic resin fine particles added to the pigment ink preferably used in the present invention is preferably 0.1% by mass or more and 10% by mass or less with respect to the total mass of the ink. It is more preferable that the content be 0.3% by mass or more and 5% by mass or less. If the addition amount is less than 0.1% by mass, it may be difficult to exert a sufficient effect on water resistance. On the other hand, if it exceeds 10% by mass, there may be a problem in terms of ink storability, such as an increase in ink viscosity and an increase in pigment dispersion particle diameter over time.

In the pigment ink of the present invention, an electric conductivity regulator can be used. For example, inorganic salts such as potassium chloride, ammonium chloride, sodium sulfate, sodium nitrate and sodium chloride; and aqueous amines such as triethanolamine. And the like.

The constituent layers of the pigment ink of the present invention and the recording medium of the present invention and the constituent layers provided as necessary include ejection stability, compatibility with a print head and an ink cartridge, storage stability, image storability, and the like. Depending on the purpose of improving the performance of the viscosity modifier, specific resistance modifier, film forming agent,
UV absorbers, antioxidants, anti-fading agents, rust inhibitors, preservatives and the like can also be added, for example, polystyrene, polyacrylates, polymethacrylates, polyacrylamides, polyethylene, polypropylene, Organic latex fine particles such as polyvinyl chloride, polyvinylidene chloride, or a copolymer thereof, urea resin, or melamine resin; oil droplet fine particles such as liquid paraffin, dioctyl phthalate, tricresyl phosphate, and silicone oil; cation or nonionic Various surfactants; ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988 and JP-A-62-261476; JP-A-57-74192, JP-A-57-87989, and JP-A-57-87989;
Nos. 0-72785 and 61-146591,
Discoloration inhibitors described in JP-A-95091 and JP-A-3-13376; JP-A-59-42993, JP-A-59-42993;
No. 52689, No. 62-280069, No. 61-24
No. 2871 and JP-A-4-219266; fluorescent whitening agents; pH adjusting agents such as sulfuric acid, phosphoric acid, citric acid, sodium hydroxide, potassium hydroxide and potassium carbonate; defoamers and preservatives And various known additives such as a thickener, an antistatic agent and a matting agent.

In the ink jet system for ejecting the pigment ink according to the present invention imagewise, the ink jet head used may be an on-demand system or a continuous system. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shared mode type, a shared wall type, etc.), an electro-thermal conversion method (for example,
Specific examples include a thermal ink jet type, a bubble jet (registered trademark) type, an electrostatic suction type (for example, an electric field control type, a slit jet type, etc.), and a discharge type (for example, a spark jet type). However, any discharge method may be used.

[0061]

EXAMPLES The present invention will be described below in detail with reference to examples, but the embodiments of the present invention are not limited to these examples.

In the examples, (%) indicates% by mass unless otherwise specified. <Preparation of Titanium Oxide Dispersion-1> Average particle size is 0.25 μm
20 kg of titanium oxide (Ishihara Sangyo, W-10)
7.5 g of sodium tripolyphosphate of 7.5, 500 g of polyvinyl alcohol (Kuraray Co., Ltd., PVA235, average degree of polymerization 3500), cationic polymer (P-
1) 150 g and defoamer (Sannobuco, SN3
81) Add to 90 liters of aqueous solution containing 10 g,
After dispersing with a high-pressure homogenizer (manufactured by Sanwa Kogyo Co., Ltd.), the total amount was finished to 100 liter to obtain a uniform titanium oxide dispersion liquid-1.

[0063]

Embedded image

<Preparation of Silica Dispersion-1> 125 kg of fumed silica (Nippon Aerosil Co., Ltd., A300) having an average primary particle size of 0.007 μm was jet-streamed inductive mixer TDS (Mitamura Riken Kogyo Co., Ltd.). 6) adjusted to pH 2.5 with nitric acid
After suction-dispersed in 20 liters of pure water at room temperature, the total amount was made up to 694 liters with pure water. When an electron micrograph of the particles of this dispersion was taken, it was confirmed that most of the particles had an average particle size of 0.01 μm or less and were dispersed to primary particles (most particles were 85 to 85 μm).
90% of particles).

<Preparation of Silica Dispersion-2> In a solution (pH = 2.3) containing 1.41 kg of the cationic polymer (P-2) and 4.2 liters of ethanol (pH = 2.3), 25 to 30 ° C. At a temperature range of 6 to 6 of silica dispersion-1.
9.4 liters were added over 20 minutes with stirring, and 7.0 liters of an aqueous solution (pH = 7.3) containing 260 g of boric acid and 230 g of borax was added over about 10 minutes, and an antifoaming agent ( 1 g of Sannobuco, Inc., SN381) was added. This mixed solution was dispersed twice with a high-pressure homogenizer (manufactured by Sanwa Kogyo Co., Ltd.) at a pressure of 24.5 MPa, and the whole amount was made up to 97 liters with pure water to prepare a substantially transparent silica dispersion liquid-2.

[0066]

Embedded image

<Preparation of Coating Liquid> Coating liquids of the first layer, the second layer and the third layer were prepared according to the following procedures.

First Layer Coating Liquid The following additives were sequentially mixed with 600 ml of the silica dispersion liquid 2 at 40 ° C. while stirring.

A 7% aqueous solution of polyvinyl alcohol (PVA235 (average degree of polymerization: 3500) manufactured by Kuraray Industries Co., Ltd.) 194.6 ml Titanium oxide dispersion-1 33 ml Latex AE-803 (manufactured by Daiichi Kogyo Co., Ltd.) 18 ml Make up to 1000 ml with water. The coating solution pH was 4.4.

The following additives were sequentially mixed with 650 ml of the silica dispersion liquid 2 at 40 ° C. with stirring.

A 7% solution of polyvinyl alcohol (manufactured by Kuraray Industries Co., Ltd., PVA235 (average degree of polymerization: 3500)) is finished to a total volume of 1000 ml with 201.6 ml pure water. The coating solution pH was 4.4.

The following additives were sequentially mixed with 650 ml of the third layer coating solution, silica dispersion liquid 2, while stirring at 40 ° C.

A 7% aqueous solution of polyvinyl alcohol (PVA235 (average degree of polymerization: 3500), manufactured by Kuraray Industries, Ltd.) 201.6 ml Silicon dispersion (BY-2 2-839, manufactured by Dow Corning Toray Silicone Co., Ltd.) 15 ml Saponin (Merck) 50% aqueous solution 4 ml Make up to 1000 ml with pure water. The pH of the coating solution was 4.5.

The coating solution obtained as described above was filtered with the following filter. First layer coating solution and second layer coating solution: Filter TCP1
0 (manufactured by Toyo Roshi Kaisha, Ltd.) two-stage filtration Coating solution for the third layer: two-stage filtration using a filter TCP30 (manufactured by Toyo Roshi Kaisha, Ltd.)
m), the second layer (100 μm), and the third layer (50 μm) are coated on both sides with polyethylene (thickness 220).
μm, the pigment ink solvent-absorbing layer was coated on a paper support containing 13% by mass of anatase-type titanium oxide with respect to polyethylene. The values in the parentheses indicate the wet film thickness, and the first to third layers were simultaneously applied.

Each coating solution was applied at 40 ° C. using a three-layer slide hopper. Immediately after the application, the coating solution was cooled in a cooling zone maintained at 0 ° C. for 20 seconds, and then blown at 25 ° C. (relative humidity 15 ° C.). %) For 60 seconds at 45 ° C (relative humidity 2
5%) for 60 seconds and 50 ° C. air (relative humidity is 25%) for 60 seconds, and then dry at 20 to 25 ° C. and a relative humidity of 40 to
The sample was wound up by adjusting the humidity in an atmosphere of 60 ° C. for 2 minutes to obtain a recording medium coated with only the pigment ink solvent absorbing layer.

Next, a coating liquid for a pigment ink receiving layer containing thermoplastic resin fine particles was prepared according to the following formulation.

Styrene-acrylic acid copolymer latex AT-2000 (manufactured by Showa Polymer Co., Ltd., Tg: 80 ° C., MFT: 85 ° C.) 50% Acrylic copolymer Na salt AS-7180 (Toagosei Co., Ltd.) 3% Water 47% Coating for a pigment ink receiving layer containing the above thermoplastic resin fine particles on the pigment ink solvent absorbing layer of a recording medium coated with only the pigment ink solvent absorbing layer. The liquid was applied by the above-mentioned slide hopper so that the film thickness after drying was 5 μm, and dried under the same drying conditions as described above to produce a recording medium.

<Preparation of Pigment Ink> (Preparation of Yellow Pigment Ink) I. Pigment Yellow 128 150 g Ethylene glycol 100 g Glycerin 80 g Ion-exchanged water 270 g is mixed, and the volume ratio is 60 with 0.3 mm zirconia beads.
% By using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.), and the dispersion is finished to 1000 g with ion-exchanged water.
And a yellow pigment ink was prepared. The average particle size of the prepared yellow pigment ink (dispersion) is 120 nm.
Met. The average particle size of the pigment ink (dispersion) was measured using Zetasizer 1000 (manufactured by Malvern).

(Preparation of Magenta Pigment Ink) I. Pigment Red 122 100 g Demol C 63 g Glycerin 100 g Deionized water 130 g was mixed, and 0.3 mm zirconia beads were mixed at a volume ratio of 6%.
The dispersion was dispersed using a horizontal bead mill (System Zeta Mini, manufactured by Ashizawa Co., Ltd.) filled with 0%, and the dispersion was adjusted to 1000 g with ion-exchanged water, and passed twice through a 1 μm millipore filter to prepare a magenta pigment ink. The average particle size of the prepared magenta pigment ink (dispersion) is 65 nm.
Met.

(Preparation of Cyan Pigment Ink) I. Pigment Blue 15: 3 100 g Demol C 63 g Diethylene glycol 100 g Deionized water 125 g is mixed, and 0.3 mm zirconia beads are mixed in a volume ratio of 6
After dispersing using a 0% -filled horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.), 20,000 rpm
After centrifugation at 30 m for 30 minutes, the resulting dispersion was made up to 1000 g with ion-exchanged water and passed twice through a 1 μm millipore filter to prepare a cyan pigment ink. The average particle size of the prepared cyan pigment ink (dispersion) was 55 nm.

(Preparation of Black Pigment Ink) Hostfine Black T (manufactured by Clariant Co., Ltd., average particle size: 50 nm) 167 g ethylene glycol 200 g triethylene glycol monomethyl ether 120 g Olfin GXL (manufactured by Nissin Chemical Co., Ltd.) 4 g Proxel GXL (Manufactured by Zeneca) 2 g The obtained dispersion was finished to 1000 g with ion-exchanged water,
A black pigment ink was prepared by passing twice through a 1 μm millipore filter.

<Image Recording on Recording Medium> Nozzle Particle Size 20
μm, drive frequency 12 kHz, number of nozzles per color 12
8, the same color nozzle density 180 dpi (dpi is 2.54
Using an on-demand type ink jet with a maximum recording density of 720 × 720 dpi equipped with a piezo type head (representing the number of dots per cm), a uniform solid image pattern of each color is formed with the above pigment ink in yellow, magenta and cyan. , And black. (Heating step and heating / pressing simultaneous step) After the above image recording,
A cylindrical iron cylinder (upper roller) with a diameter of 30 mmφ,
A silicon rubber roller (lower roller) having a diameter of 30 mmφ is coated with a tetrafluoroethylene-perfluoroalkyl ether copolymer, and a fixing device having a heater built in an iron cylinder (upper roller) is used. Adjust the surface temperature to 110 ° C. and set the conveyance speed to 10 mm / s so that the upper roller contacts the image surface.
Under the conditions of a linear pressure of 8 × 10 ⁻⁵ Pa and a nip width of 4.3 mm, a simultaneous heating and pressurizing step was performed to obtain a sample 101 of an inkjet image.

Incidentally, the coating thickness of the tetrafluoroethylene-perfluoroalkyl ether copolymer coated on the iron roller was 100 μm. The surface roughness of this upper roller is
The average surface roughness of 640 μm × 430 μm was measured using an RSTPLUS non-contact three-dimensional micro surface shape measurement system manufactured by WYCO, and was 53 nm. The surface roughness is a value after correcting the curvature of the roller. As the measurement conditions, the resolution is 368 × in the VSI mode.
238 full view, scan speed is h
It was measured at high. Term removal for analysis
Was corrected by cylinder and tilt (cylinder and tilt correction).

A sample 102 was prepared which was different from the sample 101 only in that the roller surface temperature during heating and pressing was changed to 70 ° C.

A sample 103 was produced which was different from the sample 101 only in that the average surface roughness of the pressure roller was changed to 132 nm.

Sample 104 was different from sample 101 only in that the average surface roughness of the pressure roller was changed to 198 nm.

Sample 105 was different from sample 101 only in that the average surface roughness of the pressure roller was changed to 81 nm.

The sample 101 was prepared by preparing a silicone emulsion KM862 (manufactured by Shin-Etsu Chemical Co., Ltd.) at the time of preparing a coating liquid for a pigment ink receiving layer containing thermoplastic resin fine particles at the time of producing a recording medium. 0.8% for
The only difference is that KM862 was added at 1% to the pigment component at the time of preparing each of the yellow, magenta, cyan, and black pigment inks used for image recording, and each pigment ink was prepared. Was prepared.

The sample 106 is a silicone emulsion K
A sample 107 was prepared which was different only in that M862 was changed to zinc stearate R-1004 (manufactured by Nissin Chemical Laboratory Co., Ltd.).

The sample 101 is an acrylic ester latex SX1706 (manufactured by Nippon Zeon Co., Ltd., having a particle size of 1), which is a low Tg thermoplastic resin fine particle, for each of the yellow, magenta, cyan, and black pigment inks used for image recording.
(Tm: 0 ° C.) at a concentration of 2%.

Sample 109 was different from Sample 101 in that the image sample was heated to 110 ° C. using a heater as a heating step before the simultaneous heating and pressurizing step after the image recording with the pigment ink.

A sample 110 was prepared in which the image sample was heated to 110 ° C. using a heater as a heating step after the image recording with the pigment ink and before the simultaneous heating and pressurizing step.

Sample 111 was different from Sample 106 in that the image sample was heated to 110 ° C. using a heater as a heating step after the image recording with the pigment ink and before the simultaneous heating and pressurizing step.

Sample 108 is different from Sample 108 in that an image sample is heated to 110 ° C. by using a heater as a heating step, and an image is formed before the simultaneous heating and pressurizing step after image recording with the pigment ink. .

Sample 112 differs from sample 112 in that the heating temperature in the heating step before the simultaneous heating and pressing step after image recording was 70 ° C. and the surface roughness of the heating and pressing roller (upper roller) was 132 nm. 113 were produced.

A sample 114 was different from the sample 101 in that after the image was recorded with the pigment ink, the heating temperature in the heating step was 110 ° C., and the simultaneous heating and pressurizing step was omitted.

Sample 114 refers to an acrylic acid ester latex SX1706 (manufactured by ZEON CORPORATION, particle size: 1) which is a low Tg thermoplastic resin fine particle for each of the yellow, magenta, cyan and black pigment inks used for image recording.
(00 nm, Tg: 0 ° C.) was prepared so as to be 2%.

Samples 101 to 11 thus manufactured
With respect to No. 5, glossiness, abrasion, and releasability were evaluated according to the following evaluation criteria.

(Glossiness) ：: High glossiness with no gloss difference between printed and unprinted portions ○: Glossy difference slightly with no gloss difference between printed and unprinted portions, but no practical problem △: Printing Difference in gloss between printed area and unprinted area was observed, and there was a problem in practice. ×: Large difference in gloss between printed area and unprinted area (scratching property) The degree of the decrease was classified and evaluated as follows.

◎: No discoloration was observed. ：: Slight discoloration was observed, but no problem was observed as an image. Δ: Discoloration was confirmed, image quality was reduced, and there was a problem in practical use. X: Discoloration was large. For the samples 101 to 113, which have a large influence on image quality (release properties), 30 unfixed samples were prepared after printing, fixed under each condition, and classified and evaluated as follows.

◎: No wrapping around the roller ：: 1 to 2 wrapping around the roller △: 3 to 6 wrapping around the roller, which is a problem in practice ×: 10 or more winding around the roller And the evaluation results are shown in Table 1.

[0102]

[Table 1]

As is clear from Table 1, the sample 101 (the structure of the first aspect of the present invention) is manufactured through a simultaneous heating and pressurizing step after printing. The temperature of the heating / pressing simultaneous step is 110 ° C., which is higher than the Tg of the thermoplastic resin fine particles, and the surface roughness of the pressure roller may be small, and the gloss, scratch resistance, and releasability are all low. It can be seen that the level is practically acceptable.

On the other hand, the temperature of the simultaneous heating and pressurizing step was set to 70 ° C., and the sample 102 was prepared at a temperature lower than Tg (comparative).
Is a process at a temperature lower than the glass transition point of the thermoplastic resin fine particles, so that the thermoplastic resin fine particles do not melt and form a film, and the pigment of the pigment ink applied thereon is coated with the thermoplastic resin (thermoplastic resin fine particles). The pigment ink cannot be moved into the containing pigment ink receiving layer), and the pigment ink is present on the outermost surface of the image. It can be seen that the uniformity and the scratch resistance are deteriorated.

Compared to Sample 101, Sample 103 (Comparative), in which the surface roughness of the roller in the simultaneous heating and pressing step was 132 nm and the smoothness was reduced, had slightly higher gloss uniformity than Sample 102. However, there is a practical problem, and it is necessary to improve the scratch resistance.

Samples 104 (comparison) and 105 (invention) have an average surface roughness of the pressure roller of 198 and 81 nm, respectively, whereas Sample 105 is different from Sample 104 in terms of uniform gloss, abrasion resistance and separation. It can be seen that all of the patterns have been greatly improved.

In contrast to Sample 101, Sample 106 in which the silicone emulsion was added in the pigment ink receiving layer and in the pigment ink (the structure according to the fifth aspect of the present invention) has high gloss and excellent light uniformity. You can see that. This is because in the simultaneous heating and pressurizing step, the silicone emulsion is released from the pressing roller smoothly by the releasing action, so that the smoothness of the image surface is hardly reduced and the glossiness is improved.
Regarding the scratch resistance, the same effect as that of the sample 101 is obtained. Further, it can be seen that since the silicone emulsion is provided in the pigment ink receiving layer and the pigment ink, high releasability is obtained in both the printed portion and the unprinted portion. This effect is achieved by adding the silicone emulsion to zinc stearate R-1.
It can be confirmed that the same effect as that of the sample 106 can be obtained with the sample 107 (the configuration according to the fifth aspect of the present invention) changed to 004.

In contrast to Sample 101, in Sample 108 (the structure of the invention according to the sixth aspect of the present invention), acrylate latex SX1706 (fine particles of low Tg thermoplastic resin) is added to the pigment ink. As a result, the gloss uniformity and the scratch resistance are very excellent. This is because the pigment ink containing the low Tg thermoplastic resin fine particles having a lower glass transition point than the thermoplastic resin fine particles contained in the pigment ink receiving layer adheres to the surface of the pigment ink receiving layer (thermoplastic resin fine particle containing layer). Thus, the pigment ink solvent permeates the pigment ink solvent absorbing layer adjacent to the pigment ink receiving layer. Here, when the heating and pressurizing simultaneous treatment is performed in the heating and pressurizing simultaneous step, the low Tg thermoplastic resin fine particles begin to melt prior to the thermoplastic resin fine particles originally present in the pigment ink receiving layer, and act as a plasticizer. This promotes the melting of the thermoplastic resin fine particles originally in the pigment ink receiving layer, and creates an environment in which the thermoplastic resin fine particles immediately below the pigment ink are more efficiently melted and the pigment ink is easily embedded. The uniformity of gloss in the unprinted area is enhanced.

On the other hand, the sample 109 (the configuration of the second aspect of the present invention) is different from the first embodiment in that after the image is recorded on the sample 101, the recording medium is heated in the heating step before the simultaneous heating and pressing step. ing. This is by heating in the heating step before entering the heating and pressing simultaneous step, by accelerating the melting of the thermoplastic resin particles just below the printed part, as well as the unprinted part,
This facilitates the movement of the pigment ink to the pigment ink receiving layer (thermoplastic resin layer) during the simultaneous heating and pressurizing step. This enhances gloss uniformity. On the other hand, in sample 110 (comparative), the average surface roughness was 1
Although a 32 nm roller was used, it was found that the uniformity of gloss and the abrasion resistance were deteriorated, and that the surface smoothness of the roller was important for improving the image quality.

The sample 109 (the configuration of the invention according to the fifth aspect of the present invention), 112 (the sixth aspect of the present invention)
The invention uses a silicone emulsion (release agent) and an acrylate latex (low Tg thermoplastic resin fine particles), respectively. It can be seen that the effect of the invention is further enhanced.

The sample 112 is compared with the sample 112 (comparison).
Since the heating temperature in the heating step is lower than the Tg of the thermoplastic resin fine particles and the average surface roughness of the roller in the simultaneous heating and pressing step is poor (outside the present invention), the uniformity of gloss is low and the releasability is poor. ing.

Since the sample 114 (comparative) was only heated in the heating step and the simultaneous heating and pressing step was omitted, the uniformity of gloss and the abrasion resistance were significantly poor.
The addition of the low Tg thermoplastic resin particles at 15 (comparative) to the pigment ink cannot be sufficiently improved.

[0113]

According to the present invention, it is possible to provide an ink-jet image forming method capable of obtaining an ink-jet recorded image having excellent gloss with no difference in gloss between an unprinted portion and a printed portion.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B41J 3/04 101Z (72) Inventor Hidenobu Oya 1st Sakuramachi, Hino-shi, Tokyo In-house (72) Inventor Shuji Kida 1 Konica Corporation, Sakura-cho, Hino-shi, Tokyo In-house F-term (reference) 2C056 EA04 FC01 FC02 FC06 HA45 HA46 2H086 BA05 BA15 BA31 BA34 BA41 BA59 4J039 AD03 AD04 AD10 AD11 AD15 AE04 AE11 BA04 BA31 BC19 BC39 BC60 CA06 DA02 EA15 EA16 EA17 EA19 EA20 EA21 GA24

Claims (6)

[Claims] An inkjet recording medium comprising a pigment ink receiving layer containing thermoplastic resin fine particles on the outermost surface of a support and a pigment ink solvent absorbing layer adjacent to the pigment ink receiving layer. In the simultaneous heating and pressurizing step, heating and pressurizing are performed simultaneously using two facing rollers whose average surface roughness is 100 nm or less on the side in contact with the image surface A method for forming an ink jet image, comprising: 2. A pigment ink is applied to an ink jet recording medium having a pigment ink receiving layer containing thermoplastic resin fine particles on the outermost surface of a support and a pigment ink solvent absorbing layer adjacent to the pigment ink receiving layer. Is heated in a heating step, and then heated using two facing rollers having an average surface roughness of 100 nm or less on the side in contact with the image surface in the simultaneous heating and pressing step. And pressurizing at the same time. 3. The ink-jet image forming method according to claim 1, wherein the roller surface temperature of the roller that simultaneously performs heating and pressurization is a temperature equal to or higher than the glass transition point of the thermoplastic resin fine particles. 4. The method according to claim 2, wherein both the heating temperature in the heating step and the roller surface temperature of the roller that simultaneously performs the heating and pressurization are temperatures equal to or higher than the glass transition point of the thermoplastic resin fine particles. Ink jet image forming method. 5. The ink jet according to claim 1, wherein at least one selected from the group consisting of a pigment ink receiving layer and a pigment ink contains a silicon emulsion or a metal stearate. Image forming method. 6. The pigment ink contains thermoplastic resin particles having a lower glass transition point than the thermoplastic resin particles contained in the pigment ink receiving layer.
6. The ink-jet image forming method according to any one of items 5 to 5.