JP2007076034A - Ink jet recording method and recorded matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recording method, which gives an ink jet print excellent in ink absorbency, high speed recordability, weatherability, storage stability and scratch resistance, and a recorded matter. <P>SOLUTION: In an ink jet recording method, in which ink inculding resin particles is employed to record against an ink jet recording paper having at least two ink absorbing layers consisting of a hydrophilic binder and silica particles, the ink jet recording paper is so set that the ink absorbing layer lying the farthest one from a support satisfies the conditions of formula (1): 3.0≤SiO<SB>2</SB>/(MO<SB>x</SB>/2)≤8.0 under the mass ratio changed in oxide of the ratio between a water-soluble multivalent metal compound and silica particles, has the top layer, the dry thickness of which is 2-20% of the total dry film thickness, the peak of the distribution of the water-soluble multivalent metal compound content in the depth direction of the ink absorbing layer lies within 10 μm from the top surface and the pH of the film surface is set to be 3.8-5.0. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inkjet recording method using an ink containing resin fine particles, and more specifically, high gloss and high quality having excellent environmental printing suitability, scratch resistance, high gloss uniformity and weather resistance, and bleeding resistance. The present invention relates to an ink jet recording method for obtaining an ink jet print and a recorded matter obtained thereby.

  In recent years, ink jet recording materials have been rapidly improved in image quality and approaching photographic image quality. In particular, in order to achieve image quality comparable to photographic image quality by inkjet recording, improvements have been made from the aspect of inkjet recording paper (hereinafter simply referred to as recording paper). A void-type recording paper provided with a porous layer made of a photopolymer is one of the closest to photographic image quality because of its high gloss, vivid color development, or excellent ink absorption and drying properties. It's getting connected. In particular, when a non-water-absorbing support is used, there is no occurrence of cockling after printing, as seen on a water-absorbing support, so-called “wrinkles”, and a high smooth surface can be maintained. Prints can be obtained and gradually become the mainstream of photographic prints created by inkjet recording.

  Inkjet recording is generally divided into those using water-based inks that use water and water-soluble solvents as ink solvents, and those that use non-aqueous oil-based solvents, and there are types that use dyes as coloring materials and types that use pigments, respectively. In order to obtain a high-quality recorded image, special paper suitable for each type is required. As for inks, a small amount of water-based ink is mainly used from the environmental and safety aspects.

  The void-type recording paper has high ink absorption and high-speed drying properties, but due to the refractive index of the inorganic fine particles, the film transparency is lower than that of the swelling-type recording paper. There is a problem that the color developability is lowered. As a method for improving the color developability in the void type recording paper, it is important to introduce a means for improving the transparency of the film and a means for fixing a coloring material in the ink, for example, a dye to the upper part. However, since the former naturally has a limit due to the refractive index of the inorganic fine particles, it is more important to try to improve the latter according to the latter method.

  Various proposals have been made for the above-mentioned problems in the void-type recording paper. Mainly, a cationic substance is added to the porous layer and bonded to the anionic dye to strongly fix the dye. Generally, a method for immobilizing is used. However, even if a cationic substance is simply added to the porous layer, the cationic substance is present in the entire porous layer, so it is difficult to fix the dye at the top, and until satisfactory color development is obtained. It has not reached.

  For example, JP-A-2001-287451 contains a water-soluble salt selected from an aluminum salt, a magnesium salt, a sodium salt, a potassium salt, and a zinc salt in the outermost ink-receiving layer, and a coloring component of the pigment ink. It is described that a high density and good color reproducibility can be obtained by fixing on the surface layer of the ink receiving layer. However, the inkjet recording paper described in the above patent document uses a water-soluble metal salt in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of a pigment such as silica from the viewpoint of ink absorbability and the like. As shown in the examples, this does not provide high ink absorption and dye fixing properties.

  Japanese Patent Application Laid-Open No. 2002-160442 uses a coating solution having a low content of zirconium compound or aluminum compound in a portion close to the support, and has a high content of zirconium compound or aluminum compound in a portion far from the support. By applying a multilayer coating of two or more layers using a coating solution, or by impregnating a zirconium compound or an aluminum compound into an ink absorbing layer with an overcoat on an already formed ink absorbing layer It is described that a higher amount of zirconium compound or aluminum compound is present in the part of the ink absorbing layer away from the support to suppress the occurrence of bleeding and to obtain a high image density. Sufficient zirconium compound or aluminum compound effective for obtaining the effect of fixing The reason is presumed to be absent much on the surface, not obtain bleeding resistance and ozone fading resistance is an object of the present invention.

  Japanese Patent Laid-Open No. 2001-328340 discloses that a water-soluble metal salt having a valence of 2 or more is contained in the colorant receiving layer to improve water resistance and light resistance. A layer mainly containing colloidal silica whose surface is cationically modified is provided at a position on the layer and farthest from the support. Although it is described that the drying property and the abrasion resistance are obtained, the present inventors have studied it and have found that it is still insufficient.

  On the other hand, ink-jet printing using water-soluble dye ink provides a color print comparable to photographic image quality with high image clarity and uniform surface gloss. However, prints using this water-soluble dye have poor storage stability compared to images formed with pigment inks, and are fading due to sunlight, ozone, other oxidizing gases, and the like, and image blurring is also large. It has become a challenge. In particular, in a void-type recording sheet provided with a fine porous layer, the contact area between the dye and the indoor air is widened, so that fading due to oxidizing gas in the air is greatly improved.

  For example, a method for improving light resistance and ozone gas fading resistance by adding latex or resin fine particles to ink has been proposed (see, for example, Patent Document 1). The method of adding latex or resin fine particles to the ink has a certain effect on the ozone gas fading prevention effect, but has been found to have the following problems.

  That is, the first problem is that the glossiness when the ink containing resin fine particles is applied is improved, but the glossiness does not change on the white background, and as a result, a difference in glossiness occurs between the image portion and the non-image portion. It is to end up.

  The second problem is that a good ozone fading prevention effect is recognized from the high density part to the intermediate density part where the ink amount is large, but the effect is insufficient when the ink application amount is small. The scarlet of will be conspicuous. Alternatively, a good ozone fading prevention effect is recognized in the image portion formed by the secondary color and the multi-color, but the fading is conspicuous in a portion close to a pure color, resulting in an unnatural image.

  The third problem is that a color fading prevention effect against harmful gases such as ozone gas cannot be sufficiently obtained at an image portion adjacent to a white background. This is considered to be due to the ingress of ozone gas from the adjacent white background portion or the diffusion of ozone gas to the image portion.

  In response to the above problem, for example, International Patent No. 00/06390 and Japanese Patent Application Laid-Open No. 2001-39006 include a liquid containing colorless resin fine particles at a colored ink adhesion site for the purpose of improving image storage stability or gloss. Although the technology to be applied has been disclosed, it is not possible to eliminate the gloss difference of the print and to prevent the fading against ozone gas at the image portion adjacent to the white background. Furthermore, in the colored ink application unit, image quality and gloss are degraded due to ink overflow.

  On the other hand, a technique for applying colorless ink to an area where colored ink is not applied is disclosed. For example, in JP-A-2005-88411, substantially no colorant is contained, and the amount of colorless ink containing resin fine particles is made variable so that the ozone fading and glossiness can be stably maintained even in different image density ranges. Means for improving are disclosed. However, when printing is performed on the porous ink receiving layer using ink containing resin fine particles, the resin fine particles are naturally fused on the print surface of the porous ink layer after printing to form a resin coating film. In addition, various solvents in the ink applied to the ink receiving layer cannot be completely evaporated and are easily enclosed and remain inside the ink receiving layer, resulting in a decrease in color developability due to film devitrification after printing and a constant print. When stored under hot and humid conditions, the dye as a colorant diffuses as the residual solvent diffuses, causing blurring of images and deterioration of sharpness, so-called bleeding resistance and density fluctuations during storage after printing. It has been found that there is a problem that the ink deteriorates greatly even when compared with a normal ink not containing resin fine particles.

  On the other hand, Japanese Patent Application Laid-Open No. 2005-81754 proposes improvement of gloss unevenness and scratch resistance, which are weak points of pigment ink, by using a colorless ink containing resin fine particles, but it is still insufficient.

In addition, various attempts have been made for void-type ink jet recording paper from the viewpoint of improving the quality of a printed image. As one of them, the film surface pH of the void-type ink absorbing layer is in the range of 3 to 5. Thus, a method for preventing water resistance and moisture resistance has been proposed (see, for example, Patent Document 2). However, water-based inks using ordinary dyes have not yet reached a satisfactory level of storage stability such as light resistance and gas fading.
JP 2002-240413 A JP-A-11-20306

The present invention has been made in view of the above problems, and its purpose is to have good ink absorbability, excellent high-speed recording suitability, high weather resistance, and excellent storage stability and scratch resistance. An object of the present invention is to provide an ink jet recording method which gives high gloss and high quality ink jet prints and a recorded matter obtained thereby.
Is to provide.

  The above object of the present invention is achieved by the following configurations.

  (1) In an ink jet recording method for recording on an ink jet recording paper having at least two ink absorbing layers comprising a hydrophilic binder and silica fine particles on a support using an ink jet recording ink containing at least one kind of resin fine particles. The ink jet recording paper has a mass ratio when the ratio of the water-soluble polyvalent metal compound and the silica fine particles is converted into the respective oxides in the ink absorption layer located farthest from the support. Of the water-soluble polyvalent metal compound in the depth direction of the ink absorbing layer group, the outermost layer having a dry film thickness of 2 to 20% of the total dry film thickness of the ink absorbing layer. The peak of the content distribution is within 10 μm in the depth direction from the outermost surface, and the film surface pH on the ink absorbing layer surface side is 3.8 to 5.0. Ink jet recording method.

Formula (1)
3.0 ≦ SiO ₂ / (MO _x /2)≦8.0
[Wherein, M represents a divalent or higher valent metal atom contained in the water-soluble polyvalent metal compound, and x represents a valence of the divalent or higher metal atom M. ]
(2) The inkjet recording ink containing the resin fine particles includes a colored ink containing at least one colorant and a colorless ink substantially free of a colorant, and the ink jet of the resin fine particles in the colorless ink. The inkjet recording method according to item (1), wherein the adhesion amount (g / m ² ) to the recording paper is varied depending on the adhesion amount of the resin fine particles contained in the colored ink for each recording region. .

  (3) The mass when the water-soluble polyvalent metal compound contained in the outermost layer of the inkjet recording paper is converted to oxide is A, and the water-soluble polyvalent metal compound contained in the ink absorbing layer excluding the outermost layer is oxidized. The ink jet recording method described in (1) or (2) above, wherein the mass ratio [A / (A + B)] is 0.50 or more, where B is the mass when converted to a product.

  (4) The inkjet recording method according to any one of (1) to (3), wherein the water-soluble polyvalent metal compound is a water-soluble aluminum compound or a water-soluble zirconium compound.

  (5) A recorded matter produced by the inkjet recording method described in any one of (1) to (4) above.

  According to the present invention, an ink jet recording that provides a high gloss, high quality ink jet print having good ink absorbability, excellent high-speed recording suitability, high weather resistance, and excellent storage stability and scratch resistance. A method and recorded matter obtained thereby can be provided.

  In particular, when dye ink is used, uniform gloss (glossiness, image clarity) and excellent weather resistance and storage stability can be obtained regardless of image density. When pigment ink is used, It is possible to provide an ink jet recording method capable of obtaining uniform gloss (glossiness, image clarity) and excellent print storage stability regardless of image density.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  As a result of intensive studies in view of the above problems, the present inventor has absorbed at least two layers of ink composed of a hydrophilic binder and silica fine particles on a support using an ink jet recording ink containing at least one kind of resin fine particles. In the ink jet recording method for recording on an ink jet recording paper having a layer, the ink absorbing layer located farthest from the support has a ratio of water-soluble polyvalent metal compound and silica fine particles as the ink jet recording paper. The outermost layer satisfying the conditions defined in the above formula (1) by the mass ratio when converted to ## EQU1 ## and the dry film thickness is 2 to 20% of the total dry film thickness of the ink absorbing layer, and the ink absorption The peak of the content distribution of the water-soluble polyvalent metal compound in the depth direction of the layer group is within 10 μm in the depth direction from the outermost surface, and the ink absorbing layer surface It has been found that an ink jet recording method characterized by having a film surface pH of 3.8 to 5.0 can achieve both excellent ink absorptivity, gloss uniformity, and storage stability, resulting in excellent print quality. It was possible to provide recorded materials with improved weather resistance.

  That is, the present inventor can greatly improve the image density, which is a problem peculiar to the void-type ink jet recording paper, by localizing the water-soluble polyvalent metal compound in the outermost surface area with high density, and after printing. The ink absorption layer (outermost layer) located farthest from the support is dispersed in the presence of a water-soluble polyvalent metal compound, for example, in the presence of a water-soluble polyvalent metal compound. It is possible to localize within 10 μm from the outermost surface of the ink absorbing layer group by forming with the cationic fine particle dispersion obtained by changing the pH at the time of dispersion, and the film surface pH of the ink absorbing layer It has been found that, by optimally controlling the above, excellent gloss and weather resistance can be obtained even when an ink jet recording ink containing resin fine particles (hereinafter also simply referred to as ink) is used.

  Regarding the ink jet recording paper according to the present invention having the configuration defined in the present invention, the distribution state of the water-soluble polyvalent metal compound in the depth direction of the ink absorption layer is determined by time-of-flight secondary ion mass spectrometry (TOF- As a result of analysis by SIMS, it was verified that the water-soluble polyvalent metal compound was localized at a high density on the outermost surface.

When the ratio of the water-soluble polyvalent metal compound and the silica fine particles contained in the outermost layer of the ink absorption layer is defined by the above formula (1) in terms of the mass ratio when converted into each oxide, (SiO ₂ If / MO _x ) / 2 is 8.0 or less, an effect of improving the concentration can be obtained, and if it is 3.0 or more, aggregation between layers can be suppressed and uniform coatability can be obtained.

Further, in the present invention, when the ratio of MO _x / 2 in the ink absorbing layer coating liquid for the outermost layer is increased and the dry film thickness of the outermost layer is 2 to 20% of the total dry film thickness of the ink absorbing layer, It has also been found that a preferable content distribution of the water-soluble polyvalent metal compound can be realized by setting the mass ratio [A / (A + B)] defined in claim 3 to 0.50 or more.

  It was found that when the water-soluble polyvalent metal compound-containing liquid was applied by impregnation or overcoat, the water-soluble polyvalent metal compound was not localized in the outermost surface region.

  Details of the present invention will be described below.

  First, the ink jet recording paper according to the present invention will be described.

  The inkjet recording paper according to the present invention has at least two ink absorbing layers composed of a hydrophilic binder and silica fine particles on a support, and the ink absorbing layer located farthest from the support is a water-soluble polyvalent ink. The ratio between the metal compound and the silica fine particles satisfies the condition defined by the following formula (1) in terms of mass ratio when converted into each oxide, and the dry film thickness is 2 to 20% of the total dry film thickness of the ink absorbing layer. The content distribution peak of the water-soluble polyvalent metal compound in the depth direction of the ink absorbing layer group is within 10 μm in the depth direction from the outermost surface, and the film on the ink absorbing layer surface side The surface pH is 3.8 to 5.0.

  That is, in the present invention, the content distribution peak of the water-soluble polyvalent metal compound in the depth direction of the ink absorbing layer group is within 10 μm in the depth direction from the outermost surface, and is contained in the outermost surface layer of the ink absorbing layer. The water-soluble polyvalent metal compound and the silica fine particle oxide have a mass ratio that satisfies the condition defined by the above formula (1).

  The water-soluble polyvalent metal compound content in the depth direction of the ink absorbing layer group defined in the present invention is measured using an electron probe microanalyzer (EPMA) or flight time for a sample obtained by trimming the side surface of an inkjet recording paper with a microtome or the like. Measured by determining the distribution of elements specific to polyvalent metals or specific secondary ion fragments in the thickness direction of an ink absorption layer composed of two or more layers using a scanning secondary ion mass spectrometer (TOF-SIMS) can do.

  In order to verify whether or not the water-soluble polyvalent metal compound is localized at a high density on the outermost surface, analysis by time-of-flight secondary ion mass spectrometry (TOF-SIMS) is effective in the present invention. For secondary ion mass spectrometry, see, for example, John C. et al. Vickerman and David Briggs edited by ToF-SIMS: Surface Analysis by Mass Spectrometry (Surface Spectra), Japan Surface Science Association “Secondary Ion Mass Spectrometry (Surface Analysis Technology Selection)” (Maruzen)

As a specific measurement method, a smooth ink absorption layer cross section is exposed with a microtome or the like, and TOF-SIMS measurement is performed on the ink absorption layer. Preferable ion species as primary ions at the time of TOF-SIMS measurement are metal ion species such as Au ⁺ , In ⁺ , Cs ⁺ , and Ga ⁺ , among which In ⁺ and Ga ⁺ are preferable. In addition, as a preferable secondary ion which should be detected, it selects from the secondary ion mass spectrum of the polyvalent metal measured beforehand.

  The acceleration voltage of the primary ions is preferably 20 kV to 30 kV, and various adjustments are preferably performed so that the beam diameter measured by the knife edge method is 0.25 μm or less. Irradiation conditions such as beam current and irradiation time are arbitrary. As a typical example, a primary ion beam current of 0.9 nA, an irradiation time of 20 minutes and the like are preferable measurement conditions. Note that the ink jet recording paper or the ink absorbing layer is poor in conductivity, and therefore, it is preferable to appropriately perform charge neutralization such as using a neutralizing electron gun.

  At the time of measurement, the primary ion beam is scanned within a range where the entire ink absorption layer can be measured. Typically, a 40 μm square area is scanned. It is possible to obtain an image of chemical species present in the ink absorbing layer from the scanning position of the primary ion beam and the detected secondary ions. Preferably, an image of a chemical species is obtained by obtaining a secondary ion mass spectrum at 256 × 256 points in the scanning region and recording the intensity of the target secondary ion peak from the mass spectrum. Further, by integrating the peak intensity of the same thickness portion from this image, a profile in the thickness direction of a specific secondary ion can be obtained. Creation of an image of a secondary ion and creation of a profile are usually functions attached to data processing software of a secondary ion mass spectrometer, and this function can also be used in the present invention.

  In the present invention, in the polyvalent metal profile in the thickness direction, a portion that is 1.5 times or more the minimum value of the secondary ion intensity derived from the polyvalent metal in the ink absorption layer is defined as a polyvalent metal existing portion. Stipulate. Further, the position of the ink absorbing layer and the thickness of the ink absorbing layer are the regions where the metal ions contained in the silica fine particles present in the ink absorbing layer are detected, like the polyvalent metal. The position of each ink absorption layer is set at 50% of the integrated ion intensity in the profile in the thickness direction.

  In the present invention, specifically, the amount of polyvalent metal compound distribution in the depth direction was measured under the conditions of ionic species: In and acceleration voltage: 25 kV using TRIFT-II manufactured by Physical Electronics.

  FIG. 1 is a graph showing an example of a profile of secondary ion intensity derived from a water-soluble polyvalent metal compound measured by TOF-SIMS.

  In FIG. 1, the horizontal axis indicates the measurement distance (μm) from the outermost surface to the depth direction, and the vertical axis indicates the secondary ion intensity value derived from the polyvalent metal compound measured by TOF-SIMS at each depth position. Plotted. Profile B is a typical example showing a state having a clear maximum value of ionic strength within 10 μm. In the profile A in the ink absorption layer formed by adding a polyvalent metal compound to the conventional ink absorption layer coating liquid indicated by the broken line, the maximum value of the secondary ion intensity derived from the polyvalent metal compound is the ink absorption layer. 1 (the depth is about 15 μm in FIG. 1), the fixation of the ink that has landed on the outermost part is performed more inside the ink absorption layer, and as a result, a high image density is obtained. Can't get.

  On the other hand, the profile B of the ink absorbing layer according to the present invention, which is composed of two or more ink absorbing layers and contains a high concentration of the polyvalent metal compound in the outermost layer, is derived from the polyvalent metal compound. Since the maximum value of the secondary ion intensity is within the depth of 10 μm from the outermost surface (in FIG. 1, at a depth of about 6 μm), the ink landed on the outermost surface is more fixed. As a result, a high image density can be obtained.

  Water-soluble polyvalent metal compounds applicable to the present invention include metals such as aluminum, calcium, magnesium, zinc, iron, strontium, barium, nickel, copper, scandium, gallium, indium, titanium, zirconium, tin, and lead. Examples include hydrochloride, sulfate, nitrate, acetate, formate, succinate, malonate, chloroacetate and the like. Of these, water-soluble salts composed of aluminum, calcium, magnesium, zinc and zirconium are preferred because their metal ions are colorless. Furthermore, a water-soluble aluminum compound and a water-soluble zirconium compound are particularly preferable in that they have excellent bleeding resistance during long-term storage.

  Specific examples of water-soluble aluminum compounds include polyaluminum chloride (basic aluminum chloride), aluminum sulfate, basic aluminum sulfate, aluminum potassium sulfate (alum), ammonium aluminum sulfate (ammonium alum), sodium aluminum sulfate, aluminum nitrate, phosphorus Examples thereof include aluminum oxide, aluminum carbonate, polysulfuric acid aluminum silicate, aluminum acetate, and basic aluminum lactate. Here, the water solubility in the water-soluble polyvalent metal compound means that it is dissolved in water at 20 ° C. by 1% by mass or more, more preferably 3% by mass or more.

  The most preferable water-soluble aluminum compound is basic aluminum chloride having a basicity of 80% or more from the viewpoint of ink absorbability, and can be represented by the following molecular formula.

[Al ₂ (OH) _n Cl _6-n ] _m
However, 0 <n <6, m ≦ 10, and the basicity is represented by n / 6 × 100 (%).

  Specific examples of the water-soluble zirconium compound are preferably zirconyl carbonate, zirconyl ammonium carbonate, zirconyl acetate, zirconyl nitrate, zirconium oxychloride, zirconyl lactate and zirconyl citrate. Zirconyl ammonium carbonate and zirconyl acetate are particularly preferred. In particular, zirconium oxychloride and zirconyl acetate are preferred from the viewpoint of bleeding resistance during long-term storage.

  The silica fine particles according to the present invention are preferably wet silica or vapor phase silica synthesized by precipitation or gel method using sodium silicate as a raw material.

  For example, as wet silica, Tokuyama Fine Seal Co., Ltd. by the precipitation method, and as the silica by gel method, NIPGEL from Nippon Silica Kogyo Co., Ltd. are commercially available. Precipitated silica is generally characterized by 10-60 nm, and gel silica is characterized by silica particles having primary aggregates of approximately 3-10 nm forming secondary aggregates.

  Although there is no restriction | limiting in particular in the lower limit regarding the primary particle diameter of wet silica, it is 3 nm or more from a viewpoint of manufacture stability of a silica particle, and it is preferable that it is 50 nm or less from a viewpoint of the transparency of a film | membrane. In general, wet silica synthesized by a gel method is preferred because the primary particle size tends to be smaller than that obtained by a precipitation method.

  Vapor phase silica is synthesized by combustion using silicon tetrachloride and hydrogen as raw materials. For example, Aerosil series manufactured by Nippon Aerosil Co., Ltd. is commercially available.

  In the present invention, as the silica fine particles, gas phase method silica is particularly preferred from the viewpoint that a high porosity is obtained and that coarse aggregates are hardly formed when a cationic fine particle dispersion is produced. Vapor phase silica is characterized in that secondary aggregates are formed by relatively weak interaction with wet silica and can be dispersed with low energy in wet silica.

  The vapor-phase process silica fine particles preferably have an average primary particle diameter of 3 to 50 nm. More preferably, it is 20 nm or less. If the average particle size of the primary particles is 50 nm or less, high glossiness of the recording paper can be achieved, and a clear image can be obtained by preventing the decrease in the maximum density due to irregular reflection on the surface. The average particle size of the fine particles in the above is the simple average value (number average) by observing the cross section or surface of the particle itself or the porous ink absorbing layer with an electron microscope, and determining the particle size of many arbitrary particles. As required. Here, each particle size is represented by a diameter assuming a circle equal to the projected area.

As a particularly preferred embodiment, when forming a porous ink absorption layer by forming particles of secondary particles or more, the average particle diameter is 20 to 200 nm, and the recording paper achieves high ink absorption and high gloss Further, it is also preferable to adjust the water content of the vapor-phase method silica by storing the vapor-phase method silica fine particles in an environment having a humidity of 20 to 60% for 3 days or more.

The amount of silica fine particles added depends largely on the required ink absorption capacity, the porosity of the porous ink absorption layer, and the type of hydrophilic binder, but generally 5-30 g per 1 m ² of recording paper, preferably 10-25 g. The ratio between the vapor phase method silica fine particles and the hydrophilic binder used in the ink absorbing layer is approximately 2: 1 to 20: 1 by mass ratio, and particularly preferably 3: 1 to 10: 1.

  As the amount of silica fine particles added increases, the ink absorption capacity also increases. However, there is a risk that performance such as curling and cracking may be reduced, and a method of increasing the capacity by the porosity is preferable. A preferable porosity is 40 to 75%. The porosity can be adjusted according to the type of silica fine particles to be selected, the type of binder, or the mixing ratio thereof, or the amount of other additives.

  The porosity here refers to the ratio of the total volume of the voids to the volume of the void layer, and is calculated from the total volume of the layer components and the layer thickness. Further, the total volume of the voids can be easily obtained by measuring the water absorption amount.

  Specifically, the above-mentioned cationic fine particle dispersion is obtained by dispersing (primary dispersion) by adding gas phase method silica fine particles having an anionic surface to an aqueous solution containing a water-soluble polyvalent metal compound. The obtained primary dispersion may be obtained by adding a pH adjuster and dispersing (secondary dispersion) the mixture. Alternatively, the primary dispersion in which the vapor phase silica fine particles are dispersed in water may be used as a water-soluble polyvalent. It may be obtained by mixing with an aqueous solution containing a metal compound, adding a pH adjuster, and secondarily dispersing the mixture.

  As the primary dispersion method, a known method can be used, for example, a gas phase method in a dispersion medium mainly composed of a water-soluble polyvalent compound and water using a jet stream inductor mixer manufactured by Mitamura Riken Kogyo Co., Ltd. A primary dispersion can be obtained by sucking and dispersing silica fine particles. Subsequently, a cationic fine particle dispersion mentioned here can be prepared by adding a pH adjuster to the primary dispersion and dispersing and finely pulverizing the mixture.

  Examples of the secondary dispersion method include various known dispersions such as a high-speed rotary disperser, a medium agitating disperser (such as a ball mill and a sand mill), an ultrasonic disperser, a colloid mill disperser, a roll mill disperser, and a high pressure disperser. However, an ultrasonic disperser or a high-pressure disperser is preferably used from the viewpoint of efficiently dispersing the formed vapor phase silica fine particles in an aggregated state.

  An ultrasonic disperser usually disperses by irradiating an ultrasonic wave of 20 to 25 kHz by concentrating energy on a solid-liquid interface, and is very efficiently dispersed to prepare a small amount of dispersion. Especially suitable for cases. On the other hand, the high-pressure disperser is provided with one or two homogeneous valves at the outlet of a high-pressure pump having three or five pistons, the gap of which can be adjusted by screws or hydraulic pressure. In addition, the liquid medium fed by the high-pressure pump is squeezed by the homogeneous valve and pressure is applied, and minute dust material is pulverized at the moment of passing through the homogeneous valve. Since this method can disperse a large amount of liquid continuously, it is a particularly preferable method when preparing a large amount of dispersion. The pressure applied to the homogeneous valve is usually 5 to 100 MPa, and the dispersion can be performed in one pass or can be repeated many times.

  In addition, in the cationic fine particle dispersion obtained by adding a water-soluble polyvalent metal compound to a silica slurry obtained by adding gas phase method silica fine particles in an aqueous medium and mixing and stirring, a hydrophilic binder is later used. When the ink absorbing layer coating liquid is prepared by adding the above, viscosity increase or gelation occurs, and the target coating liquid cannot be obtained.

  The cationic fine particle dispersion is preferably obtained by changing the pH from the primary dispersion state with a pH adjuster. As a result, a homogeneous cation-converted dispersion of silica fine particles can be obtained, and a stable coating liquid free from turbidity change and viscosity change can be obtained in the subsequent process of preparing the ink absorbing layer coating liquid. More preferably, the pH is raised during dispersion to obtain a cationic fine particle dispersion, and as a result, ink absorbability and ink fixability can be improved. The pH change range is preferably 0.20 or more and 1.0 or less. Here, the time of dispersion means the time of primary dispersion, that is, the period from the end of primary dispersion to the end of secondary dispersion.

  Examples of the pH adjusting acid include formic acid, acetic acid, glycolic acid, oxalic acid, propionic acid, malonic acid, succinic acid, adipic acid, maleic acid, malic acid, tartaric acid, citric acid, benzoic acid, phthalic acid, and isophthalic acid. Examples thereof include organic acids such as acid, terephthalic acid, glutaric acid, gluconic acid, lactic acid, aspartic acid, glutamic acid, pimelic acid, and suberic acid, and inorganic acids such as hydrochloric acid, nitric acid, boric acid, and phosphoric acid. Examples of the alkali include sodium hydroxide, potassium hydroxide, calcium hydroxide, aqueous ammonia, potassium carbonate, sodium carbonate, trisodium phosphate, and triethanolamine. Further, the amount of these various acids or alkalis to be added needs to be determined in consideration of the acidity or alkalinity of the various acids depending on the dispersion progress and the dispersion stability.

Among the pH adjusting agents, a boron compound is preferable. The boron compound, refers to boric acid and its salts, for example, borax, boric acid, borate (eg, orthoborate _{(e.g., InBO 3, ScBO 3, YBO} 3, LaBO 3, Mg 3 (BO 3) 2, Co ₃ (BO ₃ ) ₂ ), diborate (eg, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO) _2), tetraborate _{(eg, Na 2 B 4 O 7 ·} 10H 2 O), five borate _{(e.g., KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O ₅ )) etc. As the boron compound aqueous solution, a single aqueous solution or a mixture of two or more may be used. Particularly preferred is a mixture of borax and boric acid. Each of the aqueous solutions of boric acid and borax can be added only as a relatively dilute aqueous solution, but by mixing the two, a concentrated aqueous solution can be obtained and the dispersion can be concentrated. Further, there is an advantage that the pH can be controlled relatively freely by the mixing ratio of borax and boric acid.

  In the above dispersion, a cationic polymer having a quaternary ammonium base can be used in combination from the viewpoint of ink absorbability, film strength, and the like. Particularly preferred is a homopolymer of a monomer having a quaternary ammonium base or a copolymer with one or more monomers capable of copolymerization. When used in combination, it is preferably used in combination with a boron compound during secondary dispersion.

  Examples of the monomer having a quaternary ammonium base include the compound examples described in paragraphs [0028] and [0029] of JP-A No. 11-301096. The monomer that can be copolymerized with the quaternary ammonium base is a compound having an ethylenically unsaturated group, and examples thereof include compound examples described in paragraph [0031] of JP-A No. 11-301096.

  In particular, when the cationic polymer having a quaternary ammonium base is a copolymer, the proportion of the cationic monomer is preferably 10 mol% or more, more preferably 20 mol% or more, and particularly preferably 30 mol% or more. . The monomer having a quaternary ammonium base may be a single monomer or two or more types.

  Specific examples of the cationic polymer having a quaternary ammonium base preferably used in the present invention include the compounds described in paragraphs [0035] to [0038] of JP-A No. 11-301096.

  When preparing the cationic silica fine particle dispersion, it can be prepared by adding various additives. For example, various nonionic or cationic surfactants, antifoaming agents, nonionic hydrophilic polymers (for example, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, polyacrylamide, various sugars, gelatin, pullulan, etc.), nonions Or cationic latex dispersions, water-miscible organic solvents (for example, ethyl acetate, methanol, ethanol, isopropanol, n-propanol, acetone, etc.), inorganic salts, and the like can be used as necessary.

  In particular, a water-miscible organic solvent is preferable because formation of fine lumps is suppressed when mixed with an aqueous solution containing vapor-phase silica fine particles having an anionic surface and a water-soluble polyvalent metal compound. Such a water-miscible organic solvent is used in the dispersion in an amount of 0.1 to 20% by mass, particularly preferably 0.5 to 10% by mass.

  In the present invention, the ratio of the water-soluble polyvalent metal compound and the silica fine particles contained in the outermost layer of the ink absorption layer is a mass ratio when converted into each oxide, and the condition defined by the following formula (1) It is characterized by satisfying.

Formula (1)
_{3.0 ≦ SiO 2 / (MO x} / 2) ≦ 8.0
In the formula (1), M represents a divalent or higher valent metal atom contained in the water-soluble polyvalent metal compound, and x represents a valence of the divalent or higher metal atom M.

The oxide of the water-soluble polyvalent metal compound mentioned here is represented by MO _x / 2 in the above formula (1), and examples of the divalent metal oxide include CaO, MgO, and ZnO. Examples of the metal oxide include Al ₂ O ₃ . Examples of the tetravalent metal oxide include ZrO ₂ . According to MO _x / 2 according to formula (1), the number of oxygen atoms is displayed as a fraction for metal atoms having an odd number of valences. In this case, the number is displayed as an integer according to convention. For example, aluminum oxide becomes AlO _1.5 according to the display method of the above formula (1), but in this case, it is displayed as Al ₂ O ₃ .

  One of the characteristics of the recording paper of the present invention is that the film surface pH of the ink absorbing layer is in the range of 3.8 to 5.0 in order to exhibit the object effect of the present invention.

  As a method for adjusting the film surface pH defined in the present invention, it is possible to adjust the film surface after drying by applying an acid or alkali. However, when a non-water-absorbing support is used, an ink absorbing layer is applied. Even when the pH of the liquid itself is adjusted to a range of 3.8 to 5.0, the film surface pH in this range is often obtained after drying. Another advantage of setting the pH of the ink absorbing layer coating solution within this range is that the reactivity of the polyvalent metal compound is suppressed, and the increase in the viscosity of the ink absorbing layer coating solution is suppressed.

  In addition to the above pH adjuster, a volatile acid such as acetic acid and sodium acetate or a mixture of both can be preferably used as the pH adjuster used for adjusting the film surface pH, and the so-called pKa is 3.0 to 7.5. A salt containing a compound in the range of can be preferably used. The pH adjuster can be mixed with the polyvalent metal compound and amino acid in advance and then added to the coating solution. The solution prepared by mixing the pH adjuster, polyvalent metal compound and amino acid is in-line with the coating solution just before coating. It can also be added.

  Examples of the hydrophilic binder used in the ink jet recording paper according to the present invention include polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, casein, starch, agar, carrageenan, polyacrylic acid, polymethacrylic acid, polyacrylamide, and polymethacrylamide. Polystyrene sulfonic acid, cellulose, hydroxyl ethyl cellulose, carboxyl methyl cellulose, hydroxyl ethyl cellulose, dextran, dextrin, pullulan, water-soluble polyvinyl butyral, and the like. Two or more of these hydrophilic binders can be used in combination.

  The hydrophilic binder preferably used in the present invention is polyvinyl alcohol. In addition to ordinary polyvinyl alcohol obtained by hydrolysis of polyvinyl acetate, polyvinyl alcohol having a terminal cation-modified or anion-modified polyvinyl having an anionic group. Modified polyvinyl alcohols such as alcohol and UV-crosslinked modified polyvinyl alcohol are also included.

  The polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate preferably has an average degree of polymerization of 1000 or more, particularly preferably an average degree of polymerization of 1500 to 5000, and a saponification degree of 70 to 100. % Is preferable, and 80 to 99.5% is particularly preferable.

  Examples of the cation-modified polyvinyl alcohol have primary to tertiary amino groups and quaternary ammonium groups in the main chain or side chain of the polyvinyl alcohol as described in JP-A-61-110483. Polyvinyl alcohol, which is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

  Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride. N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1, 1-dimethyl-3-dimethylaminopropyl) acrylamide and the like.

  The ratio of the cation-modified group-containing monomer of the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative to vinyl acetate.

  Examples of the anion-modified polyvinyl alcohol include polyvinyl alcohol having an anionic group as described in JP-A-1-206088, and those described in JP-A-61-237681 and JP-A-63-307979. And a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and modified polyvinyl alcohol having a water-soluble group as described in JP-A-7-285265.

  Nonionic modified polyvinyl alcohol is, for example, a polyvinyl alcohol derivative obtained by adding a polyalkylene oxide group to a part of vinyl alcohol as described in JP-A-7-9758, and described in JP-A-8-25595. And a block copolymer of a vinyl compound having a hydrophobic group and vinyl alcohol.

  Examples of the ultraviolet crosslinking modified polyvinyl alcohol include modified polyvinyl alcohol having a photoreactive side chain as described in JP-A No. 2004-262236.

  In addition, polyvinyl alcohol may be used in combination of two or more types having different types such as the above-described degree of polymerization and modification.

  The ink jet recording paper according to the present invention preferably has polyvinyl alcohol hardened with a hardener in order to achieve excellent gloss and high porosity without incurring film brittleness.

  The hardener that can be used in the present invention is generally a compound having a group capable of reacting with polyvinyl alcohol, or a compound that promotes the reaction between different groups possessed by polyvinyl alcohol. Epoxy hardener (for example, diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl-4-glycidyloxyaniline, sorbitol Polyglycidyl ether, glycerol polyglycidyl ether, etc.), aldehyde hardeners (eg, formaldehyde, glyoxal, etc.), active halogen hardeners (eg, 2,4-dichloro-4-hydroxy-1,3,5- s-triazine etc.), Sex vinyl compound (e.g., 1,3,5-trisacryloyl - hexahydro -s- triazine, bisvinylsulfonyl methyl ether), boric acid and salts thereof, borax, aluminum alum, and isocyanate compounds. Of these, boric acid and its salts, epoxy hardeners and isocyanate compounds are preferred.

  As boric acid and salts thereof, oxygen acids having boron atom as a central atom and salts thereof are shown. Specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, octaboric acid and salts thereof Is included.

  The amount of the hardener used varies depending on the type of polyvinyl alcohol, the type of hardener, the type of silica fine particles, the ratio to polyvinyl alcohol, etc., but is usually 5 to 500 mg, preferably 10 to 300 mg, per 1 g of polyvinyl alcohol. is there.

  The above hardener may be added directly to the coating liquid when the ink absorbing layer coating liquid according to the present invention is applied, or a water-soluble coating liquid for forming an ink absorbing layer (not containing a hardener). After coating and drying, a solution containing a hardener can be supplied by overcoating.

  In the inkjet recording paper according to the present invention, the dry film thickness of the outermost layer according to the present invention is preferably 2 to 20%, more preferably 5 to 15% of the total dry film thickness of all the ink absorbing layers. . That is, by laminating two or more ink absorbing layers and containing the water-soluble polyvalent metal compound in a high concentration in the outermost layer of the ink absorbing layer, the surface absorption region can be increased in the surface area as shown in FIG. It is possible to realize an ink absorbing layer in which the maximum value of the secondary ion intensity derived from the valent metal compound appears.

The outermost layer of the ink absorbing layer according to the present invention preferably contains a surfactant. As the surfactant that can be used in the ink absorbing layer, any of cationic, betaine, and nonionic hydrocarbon, fluorine, and silicon surfactants can be used. Among these, cationic and betaine surfactants described in JP-A No. 2003-312134 are preferable from the viewpoint of coating film quality such as coating failure resistance and suitability for simultaneous multilayer coating. The amount of the surfactant used is preferably 0.0001 to 1.0 g / m ² , more preferably 0.001 to 0.5 g / m ² .

  The ink absorbing layer according to the present invention can contain a cationic polymer.

  The cationic polymer is a polymer having a primary to tertiary amine, a quaternary ammonium base, a quaternary phosphonium base, or the like in the polymer main chain or side chain, and a known compound is used for ink jet recording paper. In view of ease of production, those substantially water-soluble are preferred.

Examples of cationic polymers include polyethyleneimine, polyallylamine, polyvinylamine, dicyandiamide polyalkylene polyamine condensate, polyalkylene polyamine dicyandiamide ammonium salt condensate, dicyandiamide formalin condensate, epichlorohydrin-dialkylamine addition polymer, diallyldimethylammonium chloride Polymer, diallyldimethylammonium chloride / SO ₂ copolymer, polyvinyl imidazole, vinyl pyrrolidone / vinyl imidazole copolymer, polyvinyl pyridine, polyamidine, chitosan, cationized starch, vinyl benzyl trimethyl ammonium chloride polymer, (2-methacryloyl) Oxyethyl) trimethylammonium chloride polymer, dimethylaminoethyl methacrylate Over preparative polymer, and the like.

  Alternatively, a cationic polymer described in the Chemical Industry Times, August 15 and 25, 1998, “Polymer Drug Introduction” (published by Sanyo Chemical Industries, Ltd., p787, 1992) An example is an agent.

  Moreover, in the inkjet recording paper which concerns on this invention, it is preferable as a cationic polymer to contain the polymer which has a repeating unit represented by following General formula (1).

In the general formula (1), R represents a hydrogen atom or an alkyl group, R ₁ , R ₂ , and R ₃ each represents an alkyl group or a benzyl group, and J represents a simple bond or a divalent organic group. X ^- represents an anionic group.

In the general formula (1), the alkyl group represented by R is preferably a methyl group. The alkyl group represented by R ₁ , R ₂ and R ₃ is preferably a methyl group, an ethyl group or a benzyl group. The divalent organic group represented by J is preferably —CON (R ′) —. R ′ represents a hydrogen atom or an alkyl group.

  Examples of the anion group represented by X include halogen ions, acetate ions, methyl sulfate ions, p-toluenesulfonate, and the like.

  When the cationic polymer according to the present invention has a repeating unit represented by the general formula (1), the repeating unit represented by the general formula (1) is preferably 20 mol% or more, particularly preferably 40. ˜100 mol%.

  Specific examples of the cationic polymer having a repeating unit represented by the general formula (1) according to the present invention are shown below.

  The weight average molecular weight of the cationic polymer is generally 3000 to 200,000, preferably 5000 to 100,000. The weight average molecular weight is represented by a value in terms of polyethylene glycol determined from gel permeation chromatography.

  In addition, when the cationic polymer is added to the ink absorbing layer coating solution in advance, it may be added not only uniformly to the coating solution but also in the form of forming composite particles together with silica fine particles. As a method for preparing composite particles with silica fine particles and a cationic polymer, a method in which a cationic polymer is mixed with silica fine particles and adsorbed and coated, a method in which the coated particles are aggregated to obtain higher order composite particles, Examples thereof include a method in which coarse particles obtained by mixing are made into more uniform composite particles by a disperser.

  The cationic polymer generally has water-soluble groups and thus exhibits water-solubility, but may not dissolve in water depending on the composition of the copolymerization component, for example. Although it is preferable that it is water-soluble from the ease of manufacture, even if it is sparingly soluble in water, it can be dissolved and used using a water-miscible organic solvent.

  The water-miscible organic solvent here means alcohols such as methanol, ethanol, isopropanol, and n-propanol, glycols such as ethylene glycol, diethylene glycol, and glycerin, esters such as ethyl acetate and propyl acetate, acetone, and methyl ethyl ketone. An organic solvent that can dissolve approximately 10% or more in water, such as ketones, amides such as N, N-dimethylformamide, and the like. In this case, the amount of the organic solvent used is preferably equal to or less than the amount of water used.

The cationic polymer is usually used in the range of 0.1 to 10 g, preferably 0.2 to 5 g, per 1 m ^{2 of} inkjet recording paper.

  Various additives other than those described above can be added to the ink absorbing layer of the ink jet recording paper according to the present invention and other layers provided as necessary, and in particular, ultraviolet absorbers, antioxidants, It is preferable to contain an image preservability improving agent such as a blurring inhibitor.

  These UV absorbers and antioxidants include alkylated phenol compounds (including hindered phenol compounds), alkylthiomethylphenol compounds, hydroquinone compounds, alkylated hydroquinone compounds, tocopherol compounds, thiodiphenyl ether compounds, and two or more thioether bonds. Bisphenol compounds, O-, N-, S-benzyl compounds, hydroxybenzyl compounds, triazine compounds, phosphonate compounds, acylaminophenol compounds, ester compounds, amide compounds, ascorbic acid, amine antioxidants, 2- (2-hydroxyphenyl) benzotriazole compound, 2-hydroxybenzophenone compound, acrylate, water-soluble or hydrophobic metal salt, organometallic compound, metal complex, hindered arm Compounds (including so-called TEMPO compounds), 2- (2-hydroxyphenyl) 1,3,5, -triazine compounds, metal deactivators, phosphite compounds, phosphonite compounds, hydroxyamine compounds, nitrone compounds, peroxidation Scavenger, polyamide stabilizer, polyether compound, basic auxiliary stabilizer, nucleating agent, benzofuranone compound, indolinone compound, phosphine compound, polyamine compound, thiourea compound, urea compound, hydrazide compound, amidine compound, sugar compound, hydroxybenzoic acid Acid compounds, dihydroxybenzoic acid compounds, trihydroxybenzoic acid compounds and the like can be mentioned.

  Among these, alkylated phenol compounds, compounds having two or more thioether bonds, bisphenol compounds, ascorbic acid, amine-based antioxidants, hydrophobic metal salts, organometallic compounds, metal complexes, hindered amine compounds, hydroxyamine compounds Polyamine compounds, thiourea compounds, urea compounds, hydrazide compounds, hydroxybenzoic acid compounds, dihydroxybenzoic acid compounds, trihydroxybenzoic acid compounds and the like are preferable.

  Organic latex fine particles such as polystyrene, polyacrylic acid esters, polymethacrylic acid esters, polyacrylamides, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, or copolymers thereof, urea resin, or melamine resin Oil droplet fine particles such as liquid paraffin, dioctyl phthalate, tricresyl phosphate, silicone oil, various surfactants such as cation or nonion, JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476 JP-A-57-74192, JP-A-57-87989, JP-A-60-72785, JP-A-61-14659, JP-A-1-95091 and JP-A-3-13376. Anti-fading agent described in publications JP-A-59-42993, 59-52689, 62-280069, 61-242871, and JP-A-4-219266, etc. Contains various known additives such as pH adjusters such as phosphoric acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, antifoaming agents, preservatives, thickeners, antistatic agents, matting agents, etc. You can also.

  The support that can be used in the present invention is not particularly limited, but when a water-absorbing support such as paper is used, the smoothness of the support after printing and when water is applied to the recording paper. Is likely to cause cockling. In addition, there is a problem that dyes, zirconium compounds, or aluminum compounds may diffuse into the support to cause water resistance, bleeding, and image density reduction. Therefore, it is preferable to use a non-water-absorbing support as the support in that the effects of the present invention are remarkably exhibited.

  Examples of the water-absorbing support that can be used in the present invention include sheets and plates made of general paper, cloth, wood, etc., but especially paper is excellent in water absorption of the substrate itself and is cost-effective. It is most preferable because it is excellent. As the paper support, the main raw materials are chemical pulps such as LBKP and NBKP, mechanical pulps such as GP, CGP, RMP, TMP, CTMP, CMP, and PGW, and wood pulp such as waste paper pulp such as DIP. It is. In addition, various fibrous materials such as synthetic pulp, synthetic fiber, and inorganic fiber can be appropriately used as raw materials as necessary.

  If necessary, various conventionally known additives such as sizing agents, pigments, paper strength enhancers, fixing agents, fluorescent whitening agents, wet paper strength agents, cationizing agents and the like are added to the paper support. be able to.

  The paper support can be produced by mixing various fibrous materials such as wood pulp and various additives and using various paper machines such as a long net paper machine, a circular net paper machine, and a twin wire paper machine. If necessary, the paper can be subjected to size press treatment with starch, polyvinyl alcohol or the like, various coating treatments, or calendar treatment on a paper making stage or a paper machine.

  Examples of the non-water-absorbing support that can be preferably used in the present invention include a plastic resin film support or a support in which both surfaces of paper are coated with a plastic resin film.

  Examples of the plastic resin film support include a polyester film, a polyvinyl chloride film, a polypropylene film, a cellulose triacetate film, a polystyrene film, and a film support in which these are laminated. These plastic resin films can be transparent or translucent.

  A particularly preferred support in the present invention is a support in which both sides of paper are coated with a plastic resin, and most preferred is a support in which both sides of paper are coated with a polyolefin resin.

  As a method for producing an ink jet recording paper, each constituent layer including an ink absorbing layer can be suitably selected from a known coating method, either alone or simultaneously, and coated and dried on a support. Examples of the coating method include a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, or US Pat. Nos. 2,761,419 and 2,761,791. A slide bead coating method using an hopper, an extrusion coating method, or the like is preferably used.

  When the slide bead coating method is used, the viscosity of each coating solution when two or more constituent layers are applied simultaneously is preferably in the range of 5 to 100 mPa · s, more preferably 10 to 50 mPa · s. Range. Moreover, when using a curtain application | coating system, the range of 5-1200 mPa * s is preferable, More preferably, it is the range of 25-500 mPa * s.

  Further, the viscosity at 15 ° C. of the coating solution is preferably 100 mPa · s or more, more preferably 100 to 30,000 mPa · s, further preferably 3,000 to 30,000 mPa · s, and most preferably 10 , 30,000 to 30,000 mPa · s.

  As a coating and drying method, the coating liquid is heated to 30 ° C. or more, and after simultaneous multi-layer coating, the temperature of the formed coating film is once cooled to 1 to 15 ° C. and dried at 10 ° C. or more. Is preferred. It is preferable to prepare, apply, and dry the coating liquid at a temperature equal to or lower than the Tg of the thermoplastic resin so that the thermoplastic resin contained in the surface layer does not form a film during preparation of the coating liquid, during coating, and during drying. More preferably, the drying conditions are a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 10 to 50 ° C. Moreover, as a cooling method immediately after application | coating, it is preferable to carry out by a horizontal set system from a viewpoint of the formed coating-film uniformity.

  Moreover, it is preferable to have the process preserve | saved 24 hours or more and 60 days or less on the conditions of 35 degreeC or more and 70 degrees C or less in the manufacture process.

  The heating condition is not particularly limited as long as it is stored at a temperature of 35 ° C. or more and 70 ° C. or less for 24 hours or more and 60 days or less, but as a preferable example, for example, at 36 ° C. for 3 days to 4 weeks, 2 days to 2 weeks at 40 ° C. or 1 to 7 days at 55 ° C. By performing this heat treatment, the curing reaction of the water-soluble binder can be promoted, or the crystallization of the water-soluble binder can be promoted, and as a result, preferable ink absorbability can be achieved.

An undercoat layer can be provided on the ink absorbing layer surface side of the support for the purpose of improving adhesiveness with the ink absorbing layer. The binder for the undercoat layer is preferably a hydrophilic polymer such as gelatin or polyvinyl alcohol, or a latex polymer having a Tg of −30 to 60 ° C. These binders are used in the range of 0.001 to ² g per 1 m ^{2 of} recording paper. In the undercoat layer, a small amount of a conventionally known antistatic agent such as a cationic polymer can be contained for the purpose of antistatic.

  A back layer may be provided on the surface of the support opposite to the ink absorbing layer surface for the purpose of improving slipperiness and charging characteristics. The binder for the back layer is preferably a hydrophilic polymer such as gelatin or polyvinyl alcohol, a latex polymer having a Tg of −30 to 60 ° C., an antistatic agent such as a cationic polymer, various surfactants, and an average. A matting agent having a particle size of about 0.5 to 20 μm can also be added. The thickness of the back layer is generally 0.1 to 1 μm, but in the case where the back layer is provided for preventing curling, it is generally in the range of 1 to 20 μm. Further, the back layer may be composed of two or more layers.

  Next, an ink jet recording method using the ink jet recording paper according to the present invention will be described.

  First, the colored ink according to the present invention will be described.

  As the colored ink according to the present invention, water-based pigment ink and water-based dye ink can be preferably used.

  The water-based dye ink is an ink using a water-soluble dye as a coloring material, and is an ink obtained by mixing water or an organic solvent having high miscibility with water as an ink solvent. Examples of the dye include conventionally known azo dyes, xanthene dyes, phthalocyanine dyes, quinone dyes, anthraquinone dyes, etc., which are improved in water solubility by introducing a sulfo group or a carboxy group. Basic dyes are typically used.

  On the other hand, as the pigment used in the pigment ink, various conventionally known inorganic or organic pigment inks can be used by inkjet. Examples of inorganic pigment inks include carbon black, titanium oxide, and iron oxide. Examples of organic pigments include various azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, indigo pigments, or lake pigments obtained by reacting water-soluble dyes with polyvalent metal ions. Can do.

  These pigment particles are preferably used together with various dispersants and dispersion stabilizers such as hydrophilic polymers and surfactants. The pigment particles are preferably used in which the average particle size is dispersed to about 70 to 150 μm with these dispersed local dispersion stabilizers.

  The concentration of the dye and the pigment in the ink depends on the type of the dye or pigment, the form in which the ink is used (whether or not the dark and light ink is used), and further on the type of paper, but is generally 0.2 to 10 % By mass.

  Various solvents are used in the ink, and as such an ink solvent, water or an organic solvent having high miscibility with water can be used alone or mixed with water. Specifically, alcohol solvents such as ethanol, 2-propanol, ethylene glycol, propylene glycol, glycerin, 1,2-hexanediol, 1,6-hexanediol, diethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, 2- Amides such as pyrrolidinone, N-methylpyrrolidone, N, N-dimethylacetamide, amines such as triethanolamine, N-ethylmorpholine, triethylenetetramine, sulfolane, dimethyl sulfoxide, urea, acetonitrile, acetone, etc. These solvents may be used alone or in combination.

  In addition, various surfactants can be used in the ink for the purpose of increasing the permeability of the ink solvent and other purposes. As such a surfactant, an anionic or nonionic surfactant is preferably used. Of these, acetylene glycol surfactants are particularly preferred.

  Further, the same fine resin particles as those applied to the colorless ink described later can be added to the colored ink according to the present invention.

  Next, a colorless ink containing resin fine particles having film-forming ability according to the present invention and substantially free of a colorant will be described.

  The colorless ink according to the present invention is composed of resin fine particles having a film forming ability and a liquid medium, and preferably contains resin fine particles, a water-soluble solvent and water as main components.

  The resin fine particles according to the present invention preferably have a glass transition temperature (Tg) of −50 to 10 ° C., more preferably −20 to 10 ° C., and still more preferably −10 to 10 ° C. If the glass transition point is −50 ° C. or higher, the effects of the present invention can be stably exhibited even after storage after printing, and if the glass transition point is 10 ° C. or lower, the film will be broken after storage. Failure prevention and uniform film formation immediately after printing can be obtained.

  Further, the resin fine particles according to the present invention have a minimum film-forming temperature (MFT) because the resin fine particles in the ink stably form a resin film on the surface of the porous layer of the recording paper by natural fusion regardless of the printing environment. ) Is preferably −60 to 10 ° C. In the present invention, a film-forming auxiliary may be added to control the minimum film-forming temperature of the resin fine particles. The film-forming aid is an organic compound that is also called a plasticizer and lowers the minimum film-forming temperature of the resin latex.

  The resin fine particles are not particularly limited as long as they exhibit the effects of the present invention, and may be, for example, water-soluble resins or water-insoluble resins. A resin dispersed in water is preferable. Specific examples of the resin include acrylonitrile, styrene, acrylates (acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, methacrylic acid, methyl methacrylate, butyl methacrylate), Vinyl acetate, butadiene, vinyl chloride, polyvinylidene chloride, silicone, urethane, olefin (ethylene, propylene), or a copolymer obtained by combining two or more of these monomers is preferable.

  The resin fine particles according to the present invention preferably have an average particle size of 10 to 200 nm, more preferably 10 to 150 nm, and still more preferably 10 to 100 nm. If the average particle diameter of the resin fine particles is 10 nm or more, the resin fine particles do not penetrate into the void layer and are present on the surface of the void layer, which is preferable in terms of gloss performance. If the average particle diameter of the resin fine particles is 200 nm or less, the resin fine particles are somewhat small, which is advantageous in terms of leveling properties on the surface of the void layer, and is preferable in terms of gloss performance.

  The average particle size of the resin fine particles can be easily measured using a commercially available particle size measuring device using a light scattering method or a laser Doppler method, for example, Zetasizer 1000 (Malvern).

  The thermoplastic resin to be used is preferably less residual monomer component from the viewpoint of odor and safety, preferably 3% or less, more preferably 1% or less, especially 0.1% with respect to the solid content mass of the polymer. % Or less is preferable.

  A colorless ink containing fine resin particles and substantially free of a colorant contains 0.1 to 10% by mass of a resin component and 1 to 50% by mass of a water-soluble medium. Each functional compound such as an absorbent, an antioxidant, and an antifungal agent may be included. Furthermore, the liquid according to the present invention does not substantially contain a colorant, which means that it has substantially no function as a recording liquid. For other purposes, for example, for checking the remaining amount of ink. Or, for printing on a white background, the color may be slightly tinted for the purpose of adjusting the color tone of the white background or for confirming the discharge performance.

  As the organic solvent, surfactant, and other additives that can be added to the colorless ink according to the present invention, those that can be added to a colored ink containing a coloring material can be used.

  In the colored ink and the colorless ink according to the present invention, the surface tension of the ink is preferably 40 mN / m or less, and preferably 20 to 40 mN / m, in order to stably discharge, to increase the expression of high gloss and enhance the ozone resistance. It is more preferable. For the same reason, the ink viscosity is preferably 1.5 to 10 mPa · s, more preferably 3.0 to 8.0 mPa · s.

  Next, the colorless ink application area on the inkjet recording paper will be described.

  The colorless ink application region can be applied to at least a part of the ink jet recording paper, but from the viewpoint of further achieving the objective effect of the present invention, the colorless ink is applied to the region where the colored ink is not applied and the colored ink. It is preferable to also apply to the region where it is applied.

The amount of the colorless ink applied varies depending on the characteristics of the colored ink, the colorless ink, and the ink jet recording paper, and the appropriate amount for obtaining the effect is different, but it is preferable to apply at least 2 ml / m ² or more. However, if more colorless ink than 20 ml / m ² is applied, image quality degradation and gloss reduction are undesirable. Further, it is preferable that the amount of the colorless ink applied is adjusted so that the total amount of the colored ink and the colorless ink is within a certain range for each pixel. In this case, the minimum total amount is preferably ² ml / m ² or more, more preferably 8 ml / m ² or more and 20 ml / m ² or less.

In addition, when both colored ink and colorless ink contain resin fine particles, the total amount of resin applied by both inks for each pixel in consideration of the resin fine particles contained in the colored ink and the amount of resin contained in colorless. It is also preferable to control. In this case, the total resin amount of each pixel is preferably set to 0.05 to 1.0 g / m ^2, more preferably it is to 0.3 to 0.5 g / m ^2.

  Next, a method for applying colorless ink according to the present invention will be described.

  As a method for applying the colorless ink, any method can be used as long as it can be selected and applied to at least a part of the image. However, a method using an ink jet head as in the case of the colored ink is preferable. At this time, one or more heads for colorless ink may be prepared and colorless inks having different compositions may be applied. The colorless ink head may be fixed to the same carriage as the colored ink, or may be separated. The colorless ink may be applied before, at the same time as, or after the recording of the colored ink, but it is preferably fixed to the same carriage and applied at the same time or after the recording of the colored ink in order to achieve the effects of the present invention.

  Next, in the colored ink and the colorless ink according to the present invention, it is preferable to use alkylamines and alkanolamines as pH adjusters. The pH adjuster has an effect of suppressing an abrupt change in ink pH when the ink lands on the recording paper. Regardless of whether or not it contains a coloring material, the inclusion of the amines in the ink suppresses precipitation and aggregation due to the interaction of the fine particles upon landing with the material contained in the recording paper. This is preferable.

  Specific examples of the alkylamines that can be applied include triethylamine, diethylamine, monoethylamine, and dimethylethylamine. Examples of the alkanolamines include triethanolamine, diethanolamine, monoethanolamine, dimethylethanolamine and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<Production of recording paper>
(Preparation of silica dispersion)
(Preparation of silica dispersion D-1)
Gas phase method silica (Nippon Aerosil Co., Ltd., Aerosil 300) having an average particle size of primary particles uniformly dispersed in advance of about 0.007 μm, 25%, anionic fluorescent whitening agent (Ciba Specialty Chemicals Co., Ltd.) , 400 L of silica dispersion B-1 (pH = 2.6, containing 0.5% ethanol) containing 0.6 L of UVITEXNFW LIQUID), 12% of the cationic polymer (P-1) and 10 of n-propanol. % And ethanol 2% containing aqueous solution C-1 (pH = 2.5, containing 2 g of antifoam SN381 manufactured by Sannobuco) was added at room temperature with stirring at 3000 rpm. Next, 54 L of an aqueous solution A-1 containing 3% boric acid and 4.5% borax was gradually added with stirring.

Subsequently, it disperse | distributed with the pressure of ³ kN / cm < ² > with the high-pressure homogenizer by Sanwa Kogyo Co., Ltd., the whole quantity was finished to 630L with pure water, and the substantially transparent silica dispersion liquid D-1 was obtained.

(Preparation of silica dispersion D-2)
A silica dispersion D-2 was prepared in the same manner as in the preparation of the silica dispersion D-1, except that the anionic fluorescent whitening agent was removed.

(Preparation of silica dispersion D-3)
In the preparation of the silica dispersion D-2, instead of the cationic polymer (P-1), a basic aluminum chloride aqueous solution (manufactured by Taki Chemical: Takibaine # 1500, containing 23.75% as Al ₂ O ₃ , base A silica dispersion D-3 was prepared in the same manner except that 83.5%) was used so that SiO ₂ / Al ₂ O ₃ = 9.

  As a result of observing the dispersion state of the silica particles according to the method described in JP-A-11-321079 for the silica dispersions D-1, D-2, and D-3 prepared as described above, it was found that the composite particles were extremely stable cation-converted. I was able to confirm that

  Moreover, the silica dispersions D-1, D-2, and D-3 prepared above were filtered using a TCP-30 type filter manufactured by Advantech Toyo Co., Ltd. having a filtration accuracy of 30 μm.

[Preparation of Recording Paper 1: Comparative Example]
(Preparation of ink absorbing layer coating solution)
Using each of the silica dispersions prepared above, the following additives were sequentially mixed to prepare each ink absorption layer coating solution for the porous layer. In addition, each addition amount was displayed by the amount per 1L of coating liquid.

<First layer ink absorbing layer coating solution: lowermost layer>
Silica dispersion D-1 630 ml
5% aqueous solution of polyvinyl alcohol (Kuraray Industrial Co., Ltd .: PVA235)
270ml
5% aqueous solution of polyvinyl alcohol (Kuraray Industrial Co., Ltd .: PVA245)
90ml
Acrylic copolymer emulsion resin (Daido Kasei Kogyo; Vinizol 1083) 30ml
2% aqueous solution of surfactant (manufactured by Neos: Footage 400S) 2.0ml
The whole amount was finished to 1000 ml with pure water.

<Second layer ink absorbing layer coating solution>
Silica dispersion D-1 630 ml
5% aqueous solution of polyvinyl alcohol (Kuraray Industrial Co., Ltd .: PVA235)
270ml
5% aqueous solution of polyvinyl alcohol (Kuraray Industrial Co., Ltd .: PVA245)
90ml
Acrylic copolymer emulsion resin (Daido Kasei Kogyo Co., Ltd .: Vinizole 1083) 30ml
The whole amount was finished to 1000 ml with pure water.

<Ink absorption layer coating solution for third layer>
Silica dispersion D-2 630ml
5% aqueous solution of polyvinyl alcohol (Kuraray Industrial Co., Ltd .: PVA235)
270ml
5% aqueous solution of polyvinyl alcohol (Kuraray Industrial Co., Ltd .: PVA245)
90ml
The whole amount was finished to 1000 ml with pure water.

<Fourth layer ink absorbing layer coating solution: outermost layer>
Silica dispersion D-2 630ml
5% aqueous solution of polyvinyl alcohol (Kuraray Industrial Co., Ltd .: PVA235)
270ml
5% aqueous solution of polyvinyl alcohol (Kuraray Industrial Co., Ltd .: PVA245)
90ml
3.0 ml of 6% aqueous solution of surfactant (Kao: Cotamin 24P)
1.0 ml of a 4% aqueous solution of a surfactant (manufactured by Neos: Aftergent 400S)
The whole amount was finished to 1000 ml with pure water.

  Each ink absorbing layer coating solution prepared as described above was filtered with a TCPD-30 filter manufactured by Advantech Toyo Co., Ltd. having a filtration accuracy of 20 μm, and then filtered with a TCPD-10 filter.

(Preparation of recording paper)
Next, a slide hopper type coater is used on the paper support (RC paper) coated with polyethylene on both sides at 40 ° C. so that each of the ink absorbing layer coating solutions prepared above has the wet film thickness described below. 4 layers were simultaneously applied.

<Wet film thickness>
First layer: 42 μm (Amount of SiO _{2 applied} : 4.20 g / m ² )
Second layer: 46 μm (amount of SiO ₂ : 4.60 g / m ² )
Third layer: 44 μm (SiO ₂ weight: 4.40 g / m ² )
Fourth layer: 44 μm (SiO ₂ attached amount: 4.40 g / m ² )
The RC paper used was the following support wound on a roll having a width of about 1.5 m and a length of about 4000 m.

The RC paper used has a moisture content of 8% and a basis weight of 170 g. The surface of the photographic paper is extruded and melt coated with polyethylene containing 6% anatase-type titanium oxide at a thickness of 35 μm, and the back side is 40 μm thick. Was extruded and melt coated at a thickness of 35 μm. After corona discharge on the front side, polyvinyl alcohol (PVA235 manufactured by Kuraray Co., Ltd.) was coated with an undercoat layer so that the amount was 0.05 g per 1 m ² of RC paper. After corona discharge on the back side, Tg was about 80 ° C. A back layer containing about 0.4 g of a styrene-acrylate ester latex binder, 0.1 g of an antistatic agent (cationic polymer) and 0.1 g of about 2 μm of silica as a matting agent was applied.

  Drying after applying each ink absorbing layer coating liquid is performed by passing the cooling zone maintained at 5 ° C. for 15 seconds to reduce the temperature of the film surface to 13 ° C., and then adjusting the temperature of the plurality of drying zones appropriately. After setting and drying, the recording paper 101 was obtained by winding in a roll. The total dry film thickness of the ink absorbing layer thus formed was 45.2 μm, and the dry film thickness of the fourth layer (outermost layer) was 11.3 μm. Further, the recording paper 101 does not contain a water-soluble polyvalent metal compound in all layers.

  Further, the film surface pH of the recording paper 101 produced above was measured by the following method to be 4.6.

  The film surface pH was measured by dropping 30 μl of pure water onto the recording surface side of the ink absorption layer and using a planar electrode (GST-5313F) manufactured by Toa Denpa Inc. at room temperature.

[Production of Recording Paper 102: Comparative Example]
A basic aluminum chloride aqueous solution (manufactured by Taki Chemical Co., Ltd .: Takibaine # 1500, containing 23.75% as Al ₂ O ₃ , basicity 83.5%) is Al ₂ O on the fourth layer of the recording paper 101 produced above. _The recording paper 102 was produced by overcoating so that the amount with ₃ conversion was 0.5 g / m ² .

  The film surface pH of the produced recording paper 102 was measured by the above-described method and found to be 4.0.

[Production of Recording Paper 103: Comparative Example]
A recording paper 103 was produced in the same manner as in the production of the recording paper 101 except that the silica dispersion D-2 in the fourth layer was changed to the silica dispersion D-3. The fourth layer has an SiO ₂ coating amount of 4.40 g / m ² , an Al ₂ O ₃ coating amount of 0.5 g / m ² (SiO ₂ / Al ₂ O ₃ = 8.8), and a dry film thickness of 11 0.3 μm (25% of the total dry film thickness). A / (A + B) of the recording paper 103 is 1.0.

  The film surface pH of the produced recording paper 103 was measured by the above-described method and found to be 3.9.

[Preparation of Recording Paper 104: Comparative Example]
A silica dispersion prepared in the same manner as the silica dispersion D-3 except that the silica dispersion D-3 used for the fourth layer was changed to SiO ₂ / Al ₂ O ₃ = 4 in the production of the recording paper 103. Changed to D-4. Furthermore, the SiO ₂ application amount of the fourth layer is 2.0 g / m ² , the Al ₂ O ₃ application amount is 0.5 g / m ² , and the dry film thickness is 4.0 μm (9.4% of the total dry film thickness). A recording paper 4 was produced in the same manner except that the recording paper 4 was changed. The silica fine particles of 2.40 g / m ² were equally distributed to the first to third layers, and the total amount of SiO ^{2 applied} was the same as that of the recording paper 103.

  A / (A + B) of the recording paper 104 was 1.0, and the film surface pH was 3.5.

[Preparation of Recording Paper 105: Present Invention]
In the production of the recording paper 104, the number of moles of boron atoms contained in the aqueous solution A-1 is constant so that the film dispersion pH of the recording paper of the fourth layer of silica dispersion D-3 is 4.2. Thus, a recording paper 105 was produced in the same manner except that the silica dispersion D-5 prepared in the same manner as the silica dispersion D-3 was used except that the ratios of boric acid and borax were appropriately changed.

[Production of Recording Paper 106: Comparative Example]
In the production of the recording paper 104, the number of moles of boron atoms contained in the aqueous solution A-1 is constant so that the silica dispersion D-3 of the fourth layer has a film surface pH of 5.2 of the recording paper. Thus, a recording paper 106 was prepared in the same manner except that the silica dispersion D-6 prepared in the same manner as the silica dispersion D-3 was used except that the ratios of boric acid and borax were appropriately changed.

[Preparation of Recording Paper 107: Comparative Example]
In the production of the recording paper 101, using the silica dispersion D-5 used in the production of the recording paper 105, the SiO ₂ application amount of the third layer is 2.0 g / m ² , and the Al ₂ O ₃ application amount is 0. The recording paper 107 was prepared in the same manner except that the dry film thickness was changed to 4.0 μm (9.4% of the total dry film thickness) and 0.5 g / m ² (SiO ₂ / Al ₂ O ₃ = 4). did. The silica fine particles of 2.40 g / m ² were equally distributed to the first layer, the second layer, and the fourth layer, and the total amount of SiO ^{2 applied} was the same as that of the recording paper 101. A / (A + B) of the recording paper 7 is 0. The film surface pH of the produced recording paper 107 was measured and found to be 4.1.

[Preparation of Recording Paper 108: Present Invention]
The recording paper 105 was prepared in the same manner as the silica dispersion D-5, except that the silica dispersion D-5 used in the recording paper 105 was replaced with SiO ₂ / Al ₂ O ₃ = 7. A recording paper 108 was produced in the same manner except that the silica dispersion D-7 was used. The film surface pH of the recording paper 108 was 4.3.

[Production of Recording Paper 109: Comparative Example]
In the production of the recording paper 105, instead of the silica dispersion D-5 used in the recording paper 105, the film surface pH of the recording paper is changed to 4.0 by changing to SiO ₂ / Al ₂ O ₃ = 2.5. A recording paper 109 was prepared using a silica dispersion D-8 prepared in the same manner as the silica dispersion D-5 except that the ratios of boric acid and borax were appropriately changed.

[Preparation of Recording Paper 110 (Comparison)]
In the production of the recording paper 105, the silica dispersion D prepared in the same manner as the silica dispersion D-5 except that the silica dispersion D-5 used in the recording paper 105 was changed to SiO ₂ / Al ₂ O _3. Recording paper 110 was produced in the same manner except that -9 was used. The film surface pH of the recording paper 110 was 4.4.

[Preparation of Recording Paper 111: Present Invention]
In the production of the recording paper 105, a basic aluminum chloride aqueous solution (manufactured by Taki Chemical: Takibine # 1500, containing 23.75% as Al ₂ O ₃ , containing 83.5% basicity in the third layer ink absorbing layer coating solution). ) Was added in the same manner except that the addition amount of Al ₂ O ₃ was 0.05 g / m ² . A / (A + B) of the recording paper 111 is 0.9. The film surface pH of the recording paper 111 was 4.0.

[Preparation of Recording Paper 112: Present Invention]
In the production of the recording paper 105, zirconyl acetate (manufactured by Daiichi Rare Element Chemical Industry: Zircosol ZA) was added to the third layer in-line immediately before coating so that the ZrO ₂ equivalent weight was 0.08 g / m ^2. Similarly, a recording sheet 112 was produced. A / (A + B) of the recording paper 112 is 0.86. The film surface pH of the recording paper 112 was 4.0.

[Preparation of Recording Paper 113: Comparative Example]
In the production of the recording paper 105, a basic aluminum chloride aqueous solution (manufactured by Taki Chemical: Takibine # 1500, containing 23.75% as Al ₂ O ₃ , containing 83.5% basicity in the third layer ink absorbing layer coating solution). The recording paper 113 was prepared in the same manner except that the above was added so that the Al ₂ O ₃ equivalent weight was 0.75 g / m ² . A / (A + B) of the recording sheet 113 is 0.4. The film surface pH of the recording paper 113 was 3.8.

[Production of Recording Paper 114: Comparative Example]
In the production of the recording paper 111, a silica dispersion with SiO ₂ / Al ₂ O ₃ = 20 was used for the fourth layer, and the SiO ₂ application amount of the fourth layer was 2.0 g / m ² , Al ₂ O _3. A recording paper 114 was produced in the same manner except that the weight was changed to 0.1 g / m ² and the dry film thickness was changed to 4.0 μm (9.4% of the total dry film thickness). The silica fine particles of 2.40 g / m ² were equally distributed to the first to third layers, and the total amount of SiO ^{2 applied} was the same as that of the recording paper 111. A / (A + B) of the recording paper 114 is 1.0. The film surface pH of the recording paper 114 was 4.2.

[Preparation of Recording Paper 115: Present Invention]
In the production of the recording paper 112, the cationic polymer (P-1) of the silica dispersion D-1 used for forming the first layer to the third layer was changed to the cationic polymer (P-2). A recording sheet 115 was produced in the same manner. The film surface pH of the recording paper 115 was 4.2.

[Preparation of Recording Paper 116: Present Invention]
In the production of the recording paper 115, the recording paper 116 was prepared in the same manner except that the cationic polymer (P-2) used in the silica dispersion liquid of the first layer and the second layer was changed to the cationic polymer (P-3). Produced. The film surface pH of the recording paper 116 was 4.1.

<Characteristic evaluation of recording paper>
[Measurement of polyvalent metal compound distribution in ink absorbing layer]
After trimming the cross section of each of the recording sheets prepared above using a microtome, the cross section of the ink absorbing layer was subjected to conditions of ionic species: In and acceleration voltage: 25 kV using TRIFT-II manufactured by Physical Electronics. Then, the distribution of the aluminum ion ink absorption layer in the depth direction was determined by TOF-SIMS measurement. As a result, it was confirmed that the recording paper of the present invention had a maximum secondary ion intensity derived from aluminum ions within 10 μm in the depth direction from the outermost surface.

  As a representative example of the measurement result of the polyvalent metal compound distribution, a distribution measurement chart of the polyvalent metal compound of the comparative recording sheet 102 and the recording sheet 105 of the present invention is shown in FIGS.

  FIG. 2 shows a distribution measurement chart in the depth direction of the ink absorption layer of aluminum ions obtained by TOF-SIMS measurement of the recording paper 102 as a comparative example. In FIG. 2, the outermost layer portion is the right end of the chart, and Length 0 (μm) represents the support surface. In FIG. 2, it can be seen that the distribution of secondary ion signals derived from aluminum ions is much present in the ink absorption layer, and the basic aluminum chloride is more distributed in the interior.

  FIG. 3 shows a distribution measurement chart in the depth direction of the ink absorption layer of aluminum ions obtained by TOF-SIMS measurement of the recording paper 105 of the present invention. Similarly in FIG. 3, the outermost layer is the right end of the chart, and Length 0 (μm) represents the support surface.

  In the recording paper 105 of the present invention, secondary ion signals derived from aluminum ions are very much expressed in the region from the outermost part to a depth of 10 μm, and it can be seen that basic aluminum chloride is distributed in the surface region. .

<Preparation of ink set>
[Preparation of colorless ink]
Diethylene glycol 10% by mass
Glycerin 10% by mass
10% by mass of triethylene glycol monobutyl ether
Triethanolamine 1% by mass
Resin fine particles (SX1105: manufactured by Zeon Corporation, styrene-butadiene copolymer resin (hereinafter referred to as SBR resin), Tg: 0 ° C., average particle size: 110 nm) 1% by mass
Surfactant (Perex OT-P: manufactured by Kao, sodium dialkylsulfosuccinate)
0.5% by mass
Pure water was added to finish 100% by mass.

[Preparation of colored dye ink set]
A colored dye ink set was prepared as follows. The colored dye ink set includes yellow ink (Y), magenta ink (M), cyan ink (C) and black ink (K), and dark magenta ink (Lm) and light cyan ink (Lc). It was set as the structure of 6 colors of light color ink.

(Dark color ink: Preparation of yellow ink (Y))
Dye: Direct Yellow 86 3% by mass
Diethylene glycol 10% by mass
Glycerin 10% by mass
10% by mass of triethylene glycol monobutyl ether
Triethanolamine 1% by mass
Resin fine particles (SX1105: manufactured by Zeon Corporation, SBR resin, Tg: 0 ° C., average particle size: 110 nm) 1% by mass
Surfactant (Perex OT-P: manufactured by Kao, sodium dialkylsulfosuccinate)
0.5% by mass
Pure water was added to finish 100% by mass.

(Dark color ink: Preparation of magenta ink (M), cyan ink (C) and black ink (K))
Magenta ink (M) and cyan ink were prepared in the same manner as in the preparation of the yellow ink (Y) except that the dye was replaced with direct yellow 86 instead of the following magenta dye-1, direct blue 199, and food black 2. (C) and black ink (K) were prepared.

(Light ink: Preparation of light magenta ink (Lm))
Dye: The following magenta dye-1 0.8% by mass
Diethylene glycol 10% by mass
Glycerin 10% by mass
10% by mass of triethylene glycol monobutyl ether
Triethanolamine 1% by mass
Resin fine particles (SX1105: manufactured by Zeon Corporation, SBR resin, Tg: 0 ° C., average particle size: 110 nm) 1% by mass
Surfactant (Perex OT-P: manufactured by Kao, sodium dialkylsulfosuccinate)
0.5% by mass
Pure water was added to finish 100% by mass.

(Light ink: Preparation of light cyan ink (Lc))
A light cyan ink (Lc) was prepared in the same manner as in the preparation of the light cyan ink (Lc) except that Direct Blue 199 was used instead of the magenta dye-1.

<< Inkjet image formation >>
Using the ink jet recording apparatus shown in FIG. 4, recorded materials 1 to 16 were prepared by using the colored dye ink set and the colorless ink in combination with the recording paper prepared as described above.

  As shown in FIG. 4, the amount of ink droplets per discharge operation can be adjusted, and yellow ink (Y), magenta ink (M), cyan ink (C), black ink ( K), and a piezo-type ink jet recording apparatus equipped with recording heads of six colors of light magenta ink (Lm) and light cyan ink (Lc) and colorless ink as light color inks. Each colored ink formed an image with a droplet amount of 4 pl and a recording resolution of 1440 dpi × 1440 dpi (dpi: representing the number of dots per 2.54 cm).

The colorless ink can variably control the amount of droplets and the amount of adhesion to the recording paper. The recording resolution is 1440 dpi × 1440 dpi, and the total amount of the colored ink and the total discharge amount of the colored ink is 17 ml / m at the same time as the image formation with the colored ink. ^A surface film was formed by controlling the discharge amount of colorless ink so as to be ² .

  The ink jet recording apparatus shown in FIG. 1 used for the printing will be further described.

  In FIG. 4, the recording head 22 for colored ink and the recording head 22 for colorless ink were used, and image printing with colored ink and formation of a protective film layer with colorless ink were performed using a carriage arranged in series.

  The recording head 22 may normally be any of a piezo method, a thermal method, and a continuous method, but in this embodiment, the piezo method was used from the viewpoint of the ejection stability of ink containing resin fine particles.

  Each recording head 22 is supplied with ink from a colored ink cartridge and a colorless ink cartridge (not shown) through a tube for piping. Seven recording heads 22 are arranged along the scanning direction, and are used for six colored inks and colorless inks, respectively.

<Evaluation of recorded materials>
Each recorded material prepared as described above was subjected to the following evaluations.

[Evaluation of color development]
From the inkjet recording apparatus shown in FIG. 4, yellow ink (Y), magenta ink (M), cyan ink (C), and colorless ink are simultaneously ejected as dark inks to create a black patch, which takes 12 hours. After natural drying, the resulting black image density was measured with a GretagMacbeth optical densitometer, and this was used as a measure of color development.

[Evaluation of printing environment suitability]
Yellow ink (Y), magenta ink (M), cyan ink (C), and black ink (K) as dark inks, and light and magenta ink (Lm) and light cyan ink (Lc) as six color inks are colorless. Using 7 types of ink, each colored ink and colorless ink are ejected simultaneously using an algorithm in which the total ink application amount is 17 g / m ^{2 in} an environment of 27 ° C. and 80% RH. Thus, each of the inks was combined to form a blue image, a green image, a red image, and a black image, each consisting of eight wedge images.

  Next, the density unevenness and gloss unevenness of the printed portion were visually observed, and the environmental printing suitability was evaluated according to the following evaluation rank based on the average state of each color.

◎: No density unevenness or gloss unevenness occurred. ○: Density unevenness or gloss unevenness was observed, but there were no practical problems. △: Weak density unevenness or gloss unevenness was observed, but there were practical problems. Uneven gloss is observed [Evaluation of ozone fading resistance]
Yellow ink (Y), magenta ink (M), cyan ink (C), and black ink (K) as dark inks, and light and magenta ink (Lm) and light cyan ink (Lc) as six color inks are colorless. Using 7 types of ink, each colored ink and colorless ink are ejected simultaneously using an algorithm in which the total ink application amount is 17 g / m ^{2 in} an environment of 27 ° C. and 80% RH. 8 wedge images with different densities of yellow, magenta, cyan and black were printed in an environment of 23 ° C. and 55% RH, and left for 24 hours. Then, the reflection density of each wedge image with different densities was measured. Measured with a GretagMacbeth optical densitometer. Next, the image was exposed to an environment having an ozone concentration of 5 ppm (24 ° C., 60%) for 100 hours, and the reflection density at each density was measured again. The residual dye ratio at each density was 1 = (density after exposure) / (Concentration before exposure) × 100 (%) was calculated, and the average value in the entire concentration range was determined. Subsequently, the average value of the average dye residual ratio 2 of each of the four colors was determined, and this was set as the average dye residual ratio 3, and the ozone fading resistance was evaluated according to the following criteria.

A: Average dye residual ratio 3 is 90% or higher. O: Average dye residual ratio 3 is 80% or higher and lower than 90%. Δ: Average dye residual ratio 3 is 70% or higher and lower than 80%. ×: Average dye residual ratio 3 is 60% or more and less than 70% XX: Average dye residual ratio 3 is less than 60% [Evaluation of bleeding resistance after long-term storage]
A magenta solid image using magenta ink and colorless ink is printed in an environment of 23 ° C. and 55% RH, and a black line with a line width of about 0.3 mm with this magenta solid image as a background is black ink and colorless ink. The sample was printed using, dried for 6 hours and then inserted into a transparent clear file. This is left as a clear file in an environment of 40 ° C. and 80% RH for 3 days, and before and after storage, the black line width is measured with a microdensitometer (the reflection density is 50% of the maximum density). The width was defined as the line width), the line width change rate represented by the following formula was determined, and the bleeding resistance after long-term storage was evaluated according to the following criteria.

Line width change rate (%) = (line width of the black line after storage / line width of the black line before storage) × 100
◎: Line width change rate is 100% or more and less than 125% ○: Line width change rate is 125% or more and less than 140% Δ: Line width change rate is 140% or more and less than 160% ×: Line width change rate is 160 % Or more, less than 180% XX: Line width change rate is 180% or more [Concentration stability after printing]
Using yellow ink (Y), magenta ink (M), cyan ink (C), and colorless ink, solid images of yellow, magenta, and cyan are printed. After printing, the image is 0 in an environment of 23 ° C. and 55% RH. .5 hours and 24 hours. Each solid image density of yellow, magenta, and cyan was measured with a reflection densitometer for each color density D (0.5) after 0.5 hours and each color density D (24) after 24 hours. . Next, an absolute value of (D (24) / D (0.5) -1) × 100 was obtained for each color image, and this was used as the density variation rate (%). Next, an average value (average density fluctuation rate D (ave)) of each density fluctuation rate of yellow, magenta, and cyan was determined, and density stability after printing was evaluated according to the following criteria.

A: Average density fluctuation rate D (ave) is 0% or more and less than 5% B: Average density fluctuation rate D (ave) is 5% or more and less than 10% Δ: Average density fluctuation rate D (ave) is 10% or more Less than 15% x: Average density fluctuation rate D (ave) is 15% or more.

  As is apparent from the results shown in Table 1, the recording paper of the present invention has color developability, printing environment suitability (gloss unevenness resistance, density unevenness resistance), ozone fading resistance, bleeding resistance after long-term storage, and density after printing. It turns out that it is excellent in all of stability.

Example 2
<Preparation of colored pigment ink set>
(Preparation of pigment dispersion)
<Preparation of yellow pigment dispersion>
C. I. Pigment Yellow 74 20% by mass
Styrene-acrylic acid copolymer (molecular weight 10,000, acid value 120) 12% by mass
Diethylene glycol 15% by mass
Ion-exchanged water 53% by mass
The above additives were mixed and dispersed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0.3% zirconia beads at a volume ratio of 60% to obtain a yellow pigment dispersion. The average particle size of the obtained yellow pigment was 112 nm.

<Preparation of magenta pigment dispersion>
C. I. Pigment Red 122 25% by mass
Jonkrill 61 (acrylic-styrene resin, manufactured by Johnson)
18% by mass as solid content
Diethylene glycol 15% by mass
Ion-exchanged water 42% by mass
The above additives were mixed and dispersed using a horizontal bead mill (System Zeta Mini manufactured by Ashizawa Co., Ltd.) filled with 0.3% zirconia beads at a volume ratio of 60% to obtain a magenta pigment dispersion. The average particle size of the obtained magenta pigment was 105 nm.

<Preparation of cyan pigment dispersion>
C. I. Pigment Blue 15: 3 25% by mass
Jonkrill 61 (acrylic-styrene resin, manufactured by Johnson)
15% by mass as solid content
Glycerin 10% by mass
Ion-exchanged water 50% by mass
The above additives were mixed and dispersed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0.3% zirconia beads at a volume ratio of 60% to obtain a cyan pigment dispersion. The average particle diameter of the obtained cyan pigment was 87 nm.

<Preparation of black pigment dispersion>
Carbon black 20% by mass
Styrene-acrylic acid copolymer (molecular weight 7000, acid value 150) 10% by mass
Glycerin 10% by mass
Ion exchange water 60% by mass
The above additives were mixed and dispersed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0.3% zirconia beads at a volume ratio of 60% to obtain a black pigment dispersion. The average particle size of the obtained black pigment was 75 nm.

[Preparation of pigment ink set]
<Preparation of yellow ink>
Yellow pigment dispersion 15% by mass
20% by mass of ethylene glycol
Diethylene glycol 10% by mass
Surfactant (Surfinol 465 manufactured by Nissin Chemical Industry Co., Ltd.) 0.1% by mass
Ion exchange water was added to finish the total amount to 100% by mass.

  The mixture was then stirred and filtered through a 1 μm filter to prepare a yellow ink. The average particle diameter of the pigment in the yellow ink was 120 nm, and the surface tension γ was 36 mN / m.

<Preparation of magenta ink>
Magenta pigment dispersion 15% by mass
20% by mass of ethylene glycol
Diethylene glycol 10% by mass
Surfactant (Surfinol 465 manufactured by Nissin Chemical Industry Co., Ltd.) 1% by mass
Ion exchange water was added to finish the total amount to 100% by mass.

  Next, the mixture was stirred and filtered through a 1 μm filter to prepare a magenta ink. The average particle size of the pigment in the magenta ink was 113 nm, and the surface tension γ was 35 mN / m.

<Preparation of cyan ink>
Cyan pigment dispersion 10% by mass
20% by mass of ethylene glycol
Diethylene glycol 10% by mass
Surfactant (Surfinol 465 manufactured by Nissin Chemical Industry Co., Ltd.) 1% by mass
Ion exchange water was added to finish the total amount to 100% by mass.

  Next, the mixture was stirred and filtered through a 1 μm filter to prepare a cyan ink. The average particle size of the pigment in the cyan ink was 95 nm, and the surface tension γ was 36 mN / m.

<Preparation of black ink>
Black pigment dispersion 10% by mass
20% by mass of ethylene glycol
Diethylene glycol 10% by mass
Surfactant (Surfinol 465 manufactured by Nissin Chemical Industry Co., Ltd.) 1% by mass
Ion exchange water was added to finish the total amount to 100% by mass.

  The mixture was then stirred and filtered through a 1 μm filter to prepare a black ink. The average particle diameter of the pigment in the black ink was 85 nm, and the surface tension γ was 35 mN / m.

<< Preparation of colorless ink 2 >>
20% by mass of ethylene glycol
Diethylene glycol 10% by mass
Resin fine particles (SX1105: Nippon Zeon, styrene-butadiene copolymer resin, Tg: 0 ° C., average particle size: 110 nm) 2% by mass
Surfactant (Surfinol 465 manufactured by Nissin Chemical Industry Co., Ltd.) 1.0% by mass
Pure water was added to finish 100% by mass.

  The mixture was then stirred and filtered through a 1 μm filter to prepare colorless ink 2. The surface tension γ of the colorless ink 2 was 35 mN / m.

  Even when the prepared colorless ink 2 was mixed with the same amount of each of the prepared pigment inks, the average particle diameter of the pigment was not changed and no aggregation occurred.

<Production of recorded material>
Using the ink jet recording apparatus shown in FIG. 4, recorded materials 21 to 36 were prepared by using the colored pigment ink set and the colorless ink 2 in combination with the recording paper described in Example 1.

  Each of the recording papers produced in Example 1 was printed with an ink jet printer equipped with the above-described colored pigment ink set and colorless ink 2 in a cartridge and equipped with a piezo head incorporating the same. Image recording was performed using a cartridge of the type described in FIG. 1 of JP-A-2005-81754 so that colorless ink was ejected immediately after image recording with a colored pigment ink set.

Each colored pigment ink has a droplet amount of 4 pl, a recording resolution of 1440 dpi × 1440 dpi (dpi: representing the number of dots per 2.54 cm), and an image with a maximum total ejected ink amount of 17 ml / m ² at the image recording site. Formed.

The colorless ink is variably controlled so that the appropriate amount of liquid and the amount of adhesion to the recording paper can be controlled. The recording resolution is 1440 dpi × 1440 dpi, and at the same time as the recording image is created, the ink adhesion amount per pixel is at least 17 ml / m ² . Thus, printing was performed by varying the discharge amount of the colorless ink in accordance with the discharge amount of the colored ink.

<Evaluation of recorded materials>
[Environmental printability]
The yellow ink (Y), magenta ink (M), cyan ink (C), black ink (K) and colorless ink 2 were used under the environment of 27 ° C. and 80% RH. Using an algorithm that gives 17 g / m ² , each colored ink and colorless ink are ejected simultaneously, and each ink is combined to produce a blue image, a green image, a red image, and a black image each consisting of eight wedge images. Formed.

  Next, the density unevenness and gloss unevenness of the printed portion were visually observed, and the environmental printing suitability was evaluated according to the following evaluation rank based on the average state of each color.

◎: No density unevenness or gloss unevenness occurred. ○: Density unevenness or gloss unevenness was observed, but there were no practical problems. △: Weak density unevenness or gloss unevenness was observed, but there were practical problems. Uneven gloss is observed [Evaluation of scratch resistance]
Each solid image of yellow, magenta, cyan, blue, green, red, and black is printed in an environment of 23 ° C. and 55% RH, and the surface of each solid image is copy paper (First Class paper manufactured by Konica Minolta Business Technology). Then, it was exposed to an environment with an ozone concentration of 5 ppm (24 ° C., 60% RH) for 160 hours, the surface state was visually observed, and scratch resistance was evaluated according to the following criteria.

◎: All solid images have no scratches or paint film peeling, and no fading unevenness is observed in each color image. ○: Slight scratches or paint film peeling is observed in some solid images. Although weak density unevenness due to ozone fading is observed at the center, it is within the allowable range for practical use. Δ: Scratches and peeling of the coating are observed in all solid images, and density unevenness due to ozone fading is centered on that part. Is a quality that is a problem in practical use. ×: Strong scratches and peeling of the coating film are observed in all solid images. Table 2 shows the results obtained as described above.

  As is apparent from the results shown in Table 2, even when a colored pigment ink set containing a pigment is used as the ink jet recording ink, the recorded matter of the present invention formed from the recording paper and ink defined in the present invention is As compared with the comparative example, it can be seen that the printing environment suitability is excellent and the scratch resistance is good.

Example 3
In the recording paper 105 prepared in Example 1, a basic aluminum chloride aqueous solution (manufactured by Taki Chemical: Takibaine # 1500, 23.75% as Al ₂ O ₃ , basicity 83.5), which is a water-soluble polyvalent metal compound. %)), Basic aluminum lactate (manufactured by Taki Chemical Co., Ltd .: Taxelam G-17L; basicity 72%), zirconyl acetate (manufactured by Daiichi Rare Element Chemical Industry: Zircosol ZA), zirconium oxychloride (first rare element) Recording papers 301 to 303 were produced in the same manner except that the chemical industry product: Zircosol ZC-2) was used, and each evaluation was performed in the same manner as in the method described in Example 1. All the recording sheets were able to obtain good results equivalent to the recording sheet 105 shown in Table 1.

It is a graph which shows an example of the profile of the secondary ion intensity derived from the water-soluble polyvalent metal compound measured by the time-of-flight secondary ion mass spectrometry (TOF-SIMS). It is the distribution measurement chart of the depth direction of the ink absorption layer of the aluminum ion calculated | required by TOF-SIMS measurement of the recording paper 2 which is a comparative example. It is the distribution measurement chart of the depth direction of the ink absorption layer of the aluminum ion calculated | required by TOF-SIMS measurement of the recording paper 4 of this invention. It is a perspective view which shows an example of the inkjet printer used with the inkjet recording method of this invention.

Explanation of symbols

A Polyvalent metal compound distribution profile of comparative example B Multivalent metal compound distribution profile of the present invention 22 Recording head 23 Carriage

Claims (5)

In an ink jet recording method for recording on an ink jet recording paper having at least two ink absorbing layers comprising a hydrophilic binder and silica fine particles on a support using an ink jet recording ink containing at least one kind of resin fine particles. The recording sheet is defined by the following formula (1) in terms of the mass ratio when the ratio of the water-soluble polyvalent metal compound and the silica fine particles is converted into the respective oxides of the ink absorption layer located farthest from the support. Content distribution of the water-soluble polyvalent metal compound in the depth direction of the ink absorbing layer group, the outermost layer having a dry film thickness of 2 to 20% of the total dry film thickness of the ink absorbing layer The ink has a peak within 10 μm in the depth direction from the outermost surface, and the film surface pH on the ink absorbing layer surface side is 3.8 to 5.0. Jet recording method.
Formula (1)
3.0 ≦ SiO ₂ / (MO _x /2)≦8.0
[Wherein, M represents a divalent or higher valent metal atom contained in the water-soluble polyvalent metal compound, and x represents a valence of the divalent or higher metal atom M. ] The inkjet recording ink containing the resin fine particles comprises a colored ink containing at least one colorant and a colorless ink substantially free of a colorant, and the resin fine particles in the colorless ink are transferred to the inkjet recording paper. the inkjet recording method according to claim 1 in which the amount deposited (g / m ^2), characterized in that is variable according to the fine resin particles attached amount containing the organic color ink for each recording site. The mass when the water-soluble polyvalent metal compound contained in the outermost layer of the inkjet recording paper is converted into an oxide is A, and the water-soluble polyvalent metal compound contained in the ink absorbing layer excluding the outermost layer is converted into an oxide. 3. The ink jet recording method according to claim 1, wherein the mass ratio [A / (A + B)] is 0.50 or more when the mass at time is B. 4. The inkjet recording method according to any one of claims 1 to 3, wherein the water-soluble polyvalent metal compound is a water-soluble aluminum compound or a water-soluble zirconium compound. A recorded matter produced by the inkjet recording method according to claim 1.

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