JP2003291484A - Water-based after-treating liquid and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based after-treating liquid, with which the favorable water resistance and light resistance peculiar to a pigment ink is utilized and the realization of an ununiform gloss-free and high grade image excellent in abrasion resistance is possible, and an inkjet recording method therewith. <P>SOLUTION: This water-based after-treating liquid is to be coated by an inkjet system onto a surface to be recorded after an inkjet recording with the pigment ink onto the surface to be recorded of a recording medium having the surface to be recorded with a 75° specular gloss of 35% or more and includes one or more kinds of pigment particles selected from the group consisting of silica, alumina, calcium carbonate, barium sulfate, kaolin and a plastic pigment. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing liquid which is applied to a surface of a so-called glossy ink-jet recording paper after the ink-jet recording is performed by using a pigment ink and then applied to the surface. In addition, the present invention relates to an aqueous post-treatment liquid capable of suppressing gloss unevenness on the recording surface and improving abrasion resistance, and an ink jet recording method using the post-treatment liquid.

[0002]

2. Description of the Related Art An ink-jet system is a printing system in which ink droplets are ejected from minute nozzles in accordance with an image signal and adhered to a recording surface of a recording medium to perform printing. is there. Since a large amount of ink is used to form a high-quality full-color image comparable to a silver halide photograph, a recording medium is required to have a high ink absorption capacity. In recent years, in order to reduce the graininess in the highlight image area and form a higher quality image, a plurality of light and dark inks having the same color tone and different colorant concentrations have been used, and the demand for recording media has been increasing. Increasing levels of ink absorption are being used. Therefore, as a recording medium for ink-jet recording having a high ink absorption capacity and capable of forming a high-quality full-color image comparable to a silver halide photograph, colloidal silica, fumed silica, Ink jet recording paper having a porous ink receiving layer mainly composed of porous inorganic particles such as alumina hydrate and γ-type aluminum oxide has been developed.

[0003] Further, as an ink for ink jet recording, a colorant such as a dye or a pigment is generally dissolved or dispersed in an aqueous medium containing water, alcohol, or the like.
It is broadly divided into dye ink and pigment ink. Until now, dye inks with excellent color reproducibility and ejection stability have been widely used, but long-term storability of recorded images is regarded as important due to the expanded use of inkjet recording technology in digital photography services and commercial printing. Thus, pigment inks having better water resistance and light resistance than dye inks are being reviewed.

As a problem of the ink jet recording using the pigment ink, there is a problem that a so-called gloss unevenness occurs on the recording surface. Gloss unevenness is a phenomenon in which a difference in gloss occurs between a printed portion and a non-printed portion (white background portion) or between printed portions in which the type and amount of the colorant are different from each other. Gloss unevenness is particularly problematic when inkjet recording paper with high glossiness, so-called glossy inkjet recording paper, is used. Further, the image recorded by inkjet recording with the pigment ink is easily peeled off because it is formed by the pigment attached to the recording surface,
When the image is rubbed with a finger, the pigment may fall off and stain the recording surface, and there is a problem that the recorded image has poor abrasion resistance.

JP-A-9-286941 and JP-A-11-12516
In Japanese Patent Application Laid-Open Publication No. H11-163, a method is proposed in which an inorganic oxide colloid is added to a pigment ink to improve printing unevenness and improve fixability of the pigment. Although this method is an effective means for solving the problems of gloss unevenness and abrasion resistance, it is not sufficient, and a more effective method is required.

[0006] Conventionally, there is known a technique for improving glossiness and abrasion resistance by providing an overcoat layer made of a resin on a recording surface of a recording medium. As a method of forming the overcoat layer, a method of transferring (laminating) a transparent film onto a recording surface after image formation is known (see JP-A-2000-233474). However, this method may cause wrinkles in the film or bubbles may enter between the recording surface and the film, and there is a limit to stably form a clean and smooth overcoat layer. .

As another method for forming the overcoat layer, Japanese Patent Application Laid-Open No. 10-86544 discloses a method in which a resin liquid is applied to a recording surface by an ink jet method, and then the resin liquid is cured to form the recording medium. A method for forming a resin layer on a surface is disclosed. However, according to this method, a resin layer capable of imparting a good glossiness is provided to the above-described porous ink receiving layer because the resin liquid is quickly absorbed by the ink receiving layer before the curing treatment. There was a problem that it could not be formed.

Accordingly, an object of the present invention is to make use of the characteristics of the pigment ink such as water resistance and light resistance, and furthermore, to obtain a high quality image having no gloss unevenness and excellent abrasion resistance. An object of the present invention is to provide a processing liquid and an ink jet recording method using the same.

[0009]

The present inventors have conducted various studies on a method of performing ink-jet recording on a so-called glossy ink-jet recording paper by using a pigment ink. As a result, the ink contains specific pigment particles together with the pigment ink. By using an aqueous post-treatment liquid in combination with the aqueous post-treatment liquid and applying the aqueous post-treatment liquid to the recording surface of the gloss-based inkjet recording paper on which inkjet recording has been performed, a problem unique to inkjet recording using a pigment ink, namely, “gloss unevenness” It was found that "generation of" and "reduction of abrasion resistance" could be solved.

The present invention has been made on the basis of the above findings, and ink jet recording is performed on a recording medium having a recording surface having a 75-degree specular glossiness of 35% or more using a pigment ink. And an aqueous post-treatment liquid applied to the recording surface by an ink jet method, wherein one or more pigments selected from the group consisting of silica, alumina, calcium carbonate, barium sulfate, kaolin and plastic pigments The above object has been achieved by providing an aqueous post-treatment liquid containing particles.

Further, according to the present invention, the 75 degree specular gloss is 35%.
% Of the recording surface of the recording medium having the recording surface of not less than 10%, and an ink jet recording step of performing recording by ejecting a pigment ink onto the recording surface of the recording medium. And a post-treatment step of applying a treatment liquid by an inkjet method.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the aqueous post-treatment liquid of the present invention will be described in detail. The aqueous post-treatment liquid of the present invention is
It is used by performing ink jet recording on a recording surface of a recording medium using a pigment ink and then applying the ink to the recording surface by an ink jet method.

The aqueous post-treatment liquid of the present invention is one or two selected from the group consisting of silica, alumina, calcium carbonate, barium sulfate, kaolin and plastic pigment.
It contains at least one or more kinds of pigment particles. Examples of the plastic pigment include fine particles made of polypropylene, polystyrene, styrene-acrylic copolymer, styrene-butadiene rubber, butadiene rubber, isoprene rubber, butyl rubber, and the like. Among these pigment particles, in particular, one or more selected from the group consisting of silica, alumina and kaolin are preferable in terms of transparency and abrasion resistance of the coating film.

The above pigment particles have a pH of 20% by weight of a 20% by weight aqueous dispersion of the pigment particles from the viewpoint of preventing dissolution and corrosion of the metal plating portion inside the recording head, improving discharge stability, and the like.
Those which are stable at ~ 9 are preferred. "Stable at a pH of 6 to 9" means that when the aqueous dispersion is left at a liquid temperature of 30 ° C. for 72 hours, before and after the aqueous dispersion, the pH change is within 1 and p
H is in the range of 6 to 9, and the fluctuation of the average particle diameter of the pigment particles in the aqueous dispersion is within 50 nm.

From the viewpoint of ejection stability and the like, the above-mentioned pigment particles have a liquid temperature of 20 ° C. of a 20% by weight aqueous dispersion of the pigment particles.
Is preferred to have a viscosity of 10 mPa · s or less.

The average particle size of the pigment particles is preferably from 1 to 300 n from the viewpoint of discharge stability and transparency of the coating film.
m, more preferably 1 to 100 nm.

The content of the pigment particles in the aqueous post-treatment liquid is preferably 2 to 20% by weight, more preferably 5 to 20% by weight.
15% by weight. When the content is less than 2% by weight, the effect of suppressing uneven gloss and improving the abrasion resistance is poor, and the content is 20% by weight.
If the amount is larger than the above, aggregation and sedimentation of the pigment particles may be caused, which may lead to a decrease in ejection stability from the inkjet nozzle.

The aqueous post-treatment liquid of the present invention may contain one or more of the following various additives as required, in addition to the pigment particles.

The aqueous post-treatment liquid preferably contains a resin emulsion from the viewpoint of improving the fixability of the pigment particles to the recording surface. The resin emulsion is an aqueous liquid in which substantially spherical resin fine particles are dispersed.
As the resin, polystyrene, polyethylene, polyurethane, polyvinyl acetate, polyvinyl chloride, styrene-
Butadiene rubber, acrylic resin, styrene-acrylic copolymer, and the like. Among them, it is particularly preferable to use any one of styrene-acrylic copolymer, polystyrene and acrylic resin from the viewpoint of improvement of fixing property and weather resistance.

The average particle size of the resin in the resin emulsion is preferably from 1 to 200 nm, more preferably from 1 to 100 nm, from the viewpoints of improving ejection stability, film forming property and fixability.

The minimum film forming temperature (according to JIS K6800) of the resin emulsion is not particularly limited, but is preferably -20 to 90 ° C. from the viewpoint of improving the surface abrasion resistance of the coating film and preventing blocking. More preferably, -1
0-40 ° C.

In the resin emulsion, the content of the resin in the aqueous post-treatment liquid is preferably 0.1 to 10% by weight, more preferably 0.5 to 10% by weight, based on the weight of the aqueous post-treatment liquid. It is preferably contained so as to be 5% by weight. When the resin concentration of the aqueous post-treatment liquid is less than 0.1% by weight, the effect of fixing the pigment particles is poor, and
If the content is more than the weight percentage, the ejection stability may be reduced.

The aqueous post-treatment liquid of the present invention preferably contains a wetting agent in order to ensure discharge stability. Examples of the wetting agent include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 1,4-butanediol, Polyhydric alcohols such as 1,2-hexanediol, 1,5-pentanediol 1,6-hexanediol, 1,2,6-hexanetriol, thioglycol and hexylene glycol;
Lactams such as pyrrolidone, N-methyl-2-pyrrolidone, ε-caprolactam; ureas such as urea, thiourea, ethylene urea, 1,3-dimethylimidazolidinone;
Sugars such as maltitol, sorbitol, gluconolactone, maltose and the like can be mentioned.

The content of the above wetting agent is preferably 0.1 to 15% by weight, more preferably 3 to 15% by weight in the above aqueous post-treatment liquid.
-10% by weight.

The aqueous post-treatment liquid of the present invention preferably contains a penetrant from the viewpoint of improving the permeability to the recording medium and the ejection stability. Examples of the penetrant include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, and s.
lower alkyl alcohols such as ec-butanol, tert-butanol, iso-butanol and n-pentanol; ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene Examples thereof include alkyl ethers of polyhydric alcohols such as glycol monoethyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, and dipropylene glycol monobutyl ether.

The content of the penetrant in the aqueous post-treatment liquid is preferably 0.1 to 15% by weight, more preferably 3 to 15% by weight.
-10% by weight.

From the same viewpoint, it is preferable that the aqueous post-treatment liquid contains a surfactant. Examples of the surfactant include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium laurate, and ammonium salts of polyoxyethylene alkyl ether sulfate; polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene Nonionic surfactants such as sorbitan fatty acid esters, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene alkylamides; Surfynol 82, 104;
Acetylene glycol-based surfactants such as 440, 465, 485 (all manufactured by Air Products and Chemicals), Olfin STG and Olfin E1010 (all manufactured by Nissin Chemical Co.); cationic surfactants; Examples include amphoteric surfactants.

The content of the above surfactant is preferably 0.1 to 3% by weight, more preferably 0.2 to 1% by weight in the above aqueous post-treatment liquid.

In the above aqueous post-treatment liquid, other additives such as an ultraviolet absorber, a light stabilizer, a quencher, an antioxidant,
Waterproofing agent, fungicide, preservative, thickener, flow improver, p
An H adjuster, an antifoaming agent, a foam inhibitor, a leveling agent, an antistatic agent and the like can be contained.

The aqueous post-treatment liquid is prepared by appropriately adding, to water, a resin emulsion, a wetting agent, a penetrant, a surfactant and other various additives, as required, in addition to the pigment particles. Can be. As the water, it is preferable to use pure water or ultrapure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water. Further, water sterilized by ultraviolet irradiation or addition of hydrogen peroxide or the like is preferable in that mold and bacteria are prevented from being generated and long-term storage is possible.

The aqueous post-treatment liquid has a viscosity at a liquid temperature of 20 ° C. of 1 to 15 mPa · s, particularly 2 to 10 mPa, from the viewpoint of ensuring the stability of ejection from an ink jet nozzle.
S is preferred. From the same viewpoint, the surface tension of the aqueous post-treatment liquid is preferably 15 to 45 m.
N / m, more preferably 25 to 35 mN / m. Adjustment of viscosity and surface tension can be performed by appropriately adjusting the content of each component in the aqueous post-treatment liquid.

Next, the ink jet recording method of the present invention using the aqueous post-treatment liquid will be described.

[0033] The ink jet recording method of the present invention comprises an ink jet recording step in which a recording is performed by ejecting a pigment ink onto a recording surface of a recording medium; And a post-treatment step of applying the treatment liquid by an inkjet method.

The application of the aqueous post-treatment liquid by the ink-jet method is carried out by using an ink-jet printer as in the ink-jet recording step. Inkjet systems include a continuous system that continuously ejects ink from nozzles at regular time intervals and deflects the ejected ink droplets to form an image, and an on-demand system that ejects ink in response to image data There is a method,
Either method may be used, but the on-demand method is preferable in that fine driving control is possible and the amount of waste liquid is small.
The ink ejection control method includes a method of controlling by voltage using a piezoelectric element and a method of controlling by thermal energy using a heating resistor element, but is not particularly limited.

The ink jet recording step and the post-processing step may be performed using separate independent ink jet printers, or may be performed in one pass using the same ink jet printer. In the latter case, the ejection control of the ink and the aqueous post-treatment liquid can be performed by appropriately programming the printer driver.

The aqueous post-treatment liquid is preferably applied to the entire recording surface of the recording medium irrespective of whether or not ink has been applied, from the viewpoint of reducing gloss unevenness. Not done. The aqueous post-treatment liquid can be applied by overlapping and applying only to the portion where the ink is applied, or can be applied and applied only to a white background portion where the ink has not been applied.

The amount of the aqueous post-treatment liquid applied is preferably 1 to 5 g / m ² , more preferably ² to 5 g in terms of solid content.
/ M ² . If the coating amount is less than 1 g / m ² , the effect is poor, and if it exceeds 5 g / m ² , the transparency of the coating film may be poor.

The aqueous post-treatment liquid is excellent in quick-drying properties and is naturally dried immediately after coating. Therefore, forced drying treatment using a drying device such as an infrared heating device or a hot air heating device is particularly necessary. However, when the amount of application is large, the forced drying treatment is performed as necessary, so that the stickiness of the surface of the recorded material and the stacking due to it can be reliably prevented.

The ink jet recording method of the present invention can be carried out, for example, as follows.

FIG. 1 is a perspective view of a main part of an ink jet printer used for carrying out the ink jet recording method of the present embodiment. In a printer 10 shown in FIG. 1, a recording medium 4 is conveyed in a direction of an arrow A by a platen roller 12 driven by a paper feed motor 11, and a recording head 20 mounted on a carriage 13 is used to record the recording medium 4 on the recording medium 4. After the respective color inks and the aqueous post-treatment liquid supplied from the ink tank 30 are respectively ejected to the surface, they are carried out. The carriage 13 is connected to a carriage motor 15 via a carriage belt 14 and slides on a guide rail 16 so as to reciprocate in the arrow B ₁ or B ₂ direction orthogonal to the arrow A direction. Has become.

FIG. 2 shows the nozzle surface 20a of the recording head 20.
FIG. In FIG. 2, reference numerals 21 and 26 denote nozzle rows for discharging an aqueous post-treatment liquid.
Are nozzle rows for discharging yellow, magenta, cyan, and black inks, respectively.

The operation of the recording head 20 will be described.
When scanned Yashirube B ₁ direction, first, with respect to the recording surface of the recording medium 4, based on the received image data, performs recording by implanting the colored inks from the nozzle rows 22, 23, 24, 25 ( Subsequently, the aqueous post-treatment liquid is solid-filled from the nozzle row 26 (post-treatment step). When scanned Yashirube B ₁ direction, the nozzle row 21
Is not used. The recording head 20 has an arrowhead B _{1 in the} recording area.
Reached direction end, the recording medium 4 after being conveyed by a predetermined amount in the Yashirube A direction, is scanned Yashirube B ₂ direction. When scanned Yashirube B ₂ direction, first, the nozzle rows 25,24,23,
Recording is performed by ejecting each color ink from 22 (ink-jet recording step), and subsequently, an aqueous post-treatment liquid is solid-filled from the nozzle row 21 (post-processing step). When scanned Yashirube B ₂ direction, the nozzle array 26 is not used. By repeating such bidirectional (B ₁ and B ₂ ) scanning of the recording head 20 and the conveyance of the recording medium 4 at the end of each scan, a desired post-processed recorded material is obtained. In the recorded matter, the entire recording surface on which an image is formed is a so-called fine grain surface.

The ink jet recording method of the present invention comprises:
An inkjet recording step of performing recording by driving a pigment ink onto a recording surface of a recording medium, and a post-processing step of applying the aqueous post-treatment liquid to the recording surface on which recording has been performed in the inkjet recording step by an inkjet method The number and type of inks to be used, the specific configuration of the ink jet printer, the pattern of the ink and the aqueous post-treatment liquid, and the like are not limited to the above embodiments, and do not depart from the spirit of the present invention. Various changes are possible within the scope.

The recording medium used in the present invention will be described. The recording medium may be any uncoated paper such as plain paper or high-quality paper, or a coated paper such as an inkjet recording paper having a matte or glossy ink receiving layer, as long as it can be used for inkjet recording. Although not particularly limited, the present invention, particularly, a high gloss recording medium, that is,
This is effective when a recording medium (uncoated paper or coated paper) having a 75-degree specular glossiness (based on JIS P8142) of the recording surface of 35% or more is used.

According to the present invention, among the recording media having a high glossiness as described above, particularly, an ink jet recording paper having an ink receiving layer having a 75 ° specular glossiness of 35% or more (referred to as a glossy inkjet recording paper). It is effective when used. Glossy inkjet recording paper
Usually, an ink receiving layer containing porous inorganic particles and a binder is provided on a base material, and the ink receiving layer is mirror-finished by a casting method or the like.

Examples of the substrate include paper such as high-quality paper, recycled paper, sized paper, art paper, coated paper, cast-coated paper, resin-coated paper, resin-impregnated paper, and paper-based paper. A film or sheet-like plastic substrate of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, or the like; a nonwoven fabric, a cloth, a woven fabric, a metal film, a metal plate; Among these, it is particularly preferable to use a paper substrate, especially a resin-coated paper. The resin-coated paper is a processed paper having a configuration in which at least one side of the paper is coated with a resin, and is also called resin-coated paper or the like.

As the porous inorganic particles which are an essential component of the ink receiving layer, for example, porous amorphous silica, porous magnesium carbonate, porous alumina and the like are preferably used. The content of the porous inorganic particles is preferably about 40 to 90% by weight based on the dry weight of the ink receiving layer.

As a binder which is an essential component of the ink receiving layer, polyvinyl alcohol, vinyl acetate, an acrylic copolymer latex or the like is preferably used. The content of the binder is the same as that of the porous inorganic particles 10 described above.
It is preferably 5 to 60 parts by weight with respect to 0 parts by weight.

In the ink receiving layer, a dye fixing agent, a fluorescent whitening agent, a fungicide, a preservative, a surfactant,
Contains one or more of various additives such as thickeners, pH adjusters, defoamers, water retention agents, hardeners, coloring dyes, coloring pigments, pigment dispersants, leveling agents, ultraviolet absorbers, etc. Can be done. Further, the thickness of the ink receiving layer is preferably about 10 to 50 μm from the viewpoint of prevention of powder dropping and the like.

The pigment ink used in the present invention is not particularly limited as long as it is for inkjet recording. Pigment inks for ink jet recording generally include water containing a pigment-based colorant, and usually further contain various organic solvents, surfactants, and the like for moisturizing and adjusting permeation. In the case of a color image, ink of three primary colors of subtractive color mixture of yellow, magenta, and cyan, or ink of four or more colors obtained by adding black and other color inks thereto is used.

[0051]

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

Example 1 An aqueous post-treatment liquid 1 having the following composition was prepared.

[0053]   (Composition of aqueous post-treatment liquid 1) ・ Colloidal silica “ST-XS” Nissan Chemical 10% by weight (Average particle diameter 5 nm, pH of 20% by weight aqueous dispersion is stable at 9, liquid temperature of aqueous dispersion 2 Viscosity at 0 ° C 7 mPa · s) ・ Resin emulsion "Ex-16" made by Nippon Shokubai 2% by weight ・ Glycerin 5% by weight ・ Ethanol 5% by weight ・ Surfactant "Olfin STG" 0.4% by weight manufactured by Nissin Chemical ・ Pure water balance                                                           100% by weight in total

A six-color pigment ink jet printer (“MC200”) was applied to the recording surface of a recording medium (“PM Photo Paper” manufactured by Seiko Epson, 75 ° specular gloss 47%).
After printing a color patch of OD = 1 for cyan, magenta and yellow using an inkjet printer ("Seiko Epson"), the cyan ink of another inkjet printer ("EM930C" manufactured by Seiko Epson) and the aqueous ink The aqueous post-treatment liquid 1 was injected into the entire surface of the recording surface in a solid pattern in which cyan OD = 1 by using the one obtained by replacing the post-treatment liquid 1 (post-treatment step).
The injection of the aqueous post-treatment liquid 1 could be performed smoothly without causing troubles such as clogging of the nozzle. The ink-jet recorded material thus obtained was used as a sample of Example 1.

Example 2 An ink jet recording was produced in the same manner as in Example 1 except that the aqueous post-treatment liquid 1 having the following composition was used in place of the aqueous post-treatment liquid 1. This was used as a sample of Example 2.

[0056]   (Composition of aqueous post-treatment liquid 2) ・ Colloidal silica “ST-50” manufactured by Nissan Chemical Co., Ltd. 15% by weight (Average particle size: 25 nm, pH of 20% by weight aqueous dispersion is stable at 8, liquid temperature of aqueous dispersion Viscosity at 20 ° C 7 mPa · s) ・ Resin emulsion "Ex-35" 2% by weight made by Nippon Shokubai ・ Glycerin 5% by weight ・ Ethanol 5% by weight ・ Surfactant "Olfin STG" 0.4% by weight manufactured by Nissin Chemical ・ Pure water balance                                                           100% by weight in total

Comparative Example 1 An ink jet recorded product was manufactured in the same manner as in Example 1 except that post-processing was not performed, and this was used as a sample of Comparative Example 1.

The samples of Examples 1 and 2 and Comparative Example 1 were evaluated for uneven gloss and abrasion resistance by the following methods. The results are shown in Table 1 below.

[Evaluation Test of Gloss Unevenness] The recording surface of each sample was visually observed, and a 75-degree specular gloss (J
ISP8142) was measured, and the evaluation was made on the basis of the following evaluation criteria between the printed portion and the non-printed portion (white background portion) and between each color patch. (Evaluation criteria) A: Little difference in gloss was observed, and maximum difference in gloss was 1
It is less than 0. Good gloss uniformity. B: A slight difference in gloss is observed. Or, the maximum gloss difference is 1
0 or more and less than 20. Practically no problem level. C: Gloss difference is clearly observed. Alternatively, the maximum gloss difference is 20 or more. Not practical.

[Evaluation Test for Abrasion Resistance] An eraser (20 mm in width) was inclined on the recording surface of each sample at an inclination of 60 mm ^. With a load of 1 kg applied from above the eraser,
After the recording surface was rubbed 10 times with the eraser, the state of the recording surface was visually observed and evaluated according to the following evaluation criteria. (Evaluation Criteria) A: There is no scratch or peel on the recording surface. Good abrasion resistance. B: Some scratches are formed on the recording surface, but there is no practical problem. C: Peeling occurs on the recording surface, making it unusable for practical use.

[0061]

[Table 1]

[0062]

According to the present invention, a high-quality image having no gloss unevenness and excellent in abrasion resistance is realized by using the above-mentioned aqueous post-treatment liquid after inkjet recording using a pigment ink. be able to. Further, since this image is formed by a pigment ink having excellent water resistance, light resistance, and the like, it has excellent long-term storability as compared with a recorded matter having an image formed by a dye ink. Further, since the aqueous post-treatment liquid is excellent in ejection stability, there is no possibility of clogging of the ink jet nozzle and the like, and a high-quality recorded matter can be obtained at a relatively low cost by a simple process.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an ink jet printer used in an embodiment of an ink jet recording method of the present invention.

FIG. 2 is a front view of a nozzle surface of a recording head in the ink jet printer shown in FIG.

[Explanation of symbols]

10 Inkjet printer 11 Paper feed motor 12 Platen roller 13 Carriage 14 Carriage belt 15 Carriage motor 16 Guide Roll 20 Recording head 20a Nozzle surface 21 to 26 nozzles 30 ink tank

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 2C056 EA13 HA44                 2H086 BA01 BA02 BA05 BA15 BA33                       BA53 BA59 BA60 BA61 BA62                 4J039 AD03 AD10 BA13 BA18 BA21                       BA23 BA32 BE15 BE22 CA06                       EA33 EA36 GA24

Claims (14)

[Claims] 1. A recording medium having a recording surface having a 75-degree specular glossiness of 35% or more is subjected to ink-jet recording using a pigment ink on the recording surface, and then applied to the recording surface by an ink-jet method. An aqueous post-treatment liquid to be applied, comprising one or more pigment particles selected from the group consisting of silica, alumina, calcium carbonate, barium sulfate, kaolin, and plastic pigment. Processing liquid. 2. The aqueous post-treatment liquid according to claim 1, wherein said pigment particles are stable at a pH of 6 to 9 in a 20% by weight aqueous dispersion of said pigment particles. 3. The viscosity of the above-mentioned pigment particles at a liquid temperature of 20 ° C. of a 20% by weight aqueous dispersion of the pigment particles is 10 mPa · s.
3. The method according to claim 1, wherein:
An aqueous post-treatment liquid as described above. 4. The pigment particles have an average particle diameter of 1 to 300.
The aqueous post-treatment liquid according to any one of claims 1 to 3, wherein 5. The aqueous post-treatment liquid according to claim 1, comprising 2 to 20% by weight of the pigment particles. 6. The aqueous post-treatment liquid according to claim 1, comprising a resin emulsion, wherein the content of the resin is 0.1 to 10% by weight. 7. The aqueous post-treatment liquid according to claim 6, wherein the resin is one of a styrene-acryl copolymer, polystyrene and an acrylic resin. 8. It contains a wetting agent, the content of which is 0.1 to
The aqueous post-treatment liquid according to any one of claims 1 to 7, wherein the amount is 15% by weight. 9. The aqueous post-treatment liquid according to claim 1, comprising one or more selected from the group consisting of a penetrant and a surfactant. 10. An ink-jet recording step in which a recording medium having a recording surface having a 75-degree specular glossiness of 35% or more is recorded by ejecting a pigment ink onto the recording surface, and recording is performed in the ink-jet recording step. An inkjet recording method, comprising: a post-treatment step of applying the aqueous post-treatment liquid according to any one of claims 1 to 9 to the recording surface by an inkjet method. 11. The ink jet recording method according to claim 10, wherein said aqueous post-treatment liquid is applied to the entire surface of said recording surface. 12. The amount of the aqueous post-treatment liquid applied is a solid content.
1 to 5 g / m in conversion ^Two2. The method according to claim 1, wherein
12. The ink jet recording method according to 0 or 11. 13. The ink jet recording method according to claim 10, wherein the recording medium has an ink receiving layer containing porous inorganic particles and a binder. 14. A recorded matter recorded by the ink jet recording method according to claim 10.