JP2000255162A - Inkjet recording medium, recording method and recorded matter - Google Patents

Abstract

(57) [Summary] [PROBLEMS] It is possible to apply to a printer or the like using a general ink jet recording method without requiring a special device, and it is possible to easily trace a forged copy printed matter. Provided are an inkjet recording medium, a recording method, and a recorded matter. SOLUTION: This is an ink jet recording medium having at least a substrate and an ink receiving layer provided on the substrate, on which an image is recorded by an ink composition.
An ink jet recording medium, a recording method, and a recorded matter, wherein the ink receiving layer contains at least a diazonium salt compound and a coupler that reacts with the diazonium salt compound to form a color.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording medium, a recording method and a recorded matter, and more particularly, to an ink jet recording medium containing a heat-sensitive and pressure-sensitive coloring material, a recording method and a recorded matter.

[0002]

2. Description of the Related Art In recent years, image recording apparatuses capable of copying or duplicating color images, such as color copying machines and color printers, have become extremely high-performance. For this reason, a recorded matter reproduced using this image recording apparatus can obtain a very high-quality color image. In particular, the quality of the recorded matter using the recording apparatus of the ink jet system has been dramatically improved in accordance with the improvement in the performance of the ink. For this reason, there has been a risk that fraudulent creation of, for example, gift certificates, securities, bills, and the like, which should not be copied by using the recording apparatus of the ink jet system, has emerged.

However, if a copy of a printed material that should not be copied is made and the copy is misused, if the image forming apparatus such as a copying machine that made the copy can be identified, a criminal investigation is performed. Not only does it help, but it also has the effect of eliminating the motivation for abusing the copy.

[0004] In order to prevent such misuse of the copied material, as a conventional technology for facilitating the tracking search of the forged copied material, for example, a specific marking which is hard to be visually recognized and specific information is printed on an image or a recorded material. A writing method has been proposed (a technique disclosed in Japanese Patent Application Laid-Open No. 9-227817). JP-A-6-059601 discloses that an image reading unit, an image processing unit, and an image generation unit that generates an image on a recording sheet based on image information after image processing are visually recognized easily. An “image forming apparatus” including an information writing unit that writes various types of information using a special ink that cannot be used, a detection sensor, and a system controller is disclosed.

[0005]

However, the above-mentioned information writing method for facilitating the tracking search of the forged copy printed matter in the related art is based on various kinds of information itself using special ink different from that for image formation. Need to be written, a special device is required for the writing, and it is difficult to apply the method to a printer or the like using a general ink jet recording method.

The present invention has been made in view of the above-mentioned conventional problems, and does not require a special device, and can be applied to a printer using a general ink jet recording method. An object of the present invention is to provide an ink jet recording medium, a recording method, and a recorded material that can facilitate a tracking search of a copied printed material.

[0007]

According to the present invention, there is provided an ink jet recording medium comprising at least a base material and an ink receiving layer provided on the base material. An ink jet recording medium according to claim 1, characterized in that the ink receiving layer contains at least a diazonium salt compound and a coupler that reacts with the diazonium salt compound to form a color (claim 1). In this manner, by mixing a diazonium salt compound and a coupler that reacts with the diazonium salt compound to form a color, the coloring is caused by applying heat or pressure energy to the recording medium. be able to.

The content of the diazonium salt compound is 0.1 to 10% by weight, and the content of the coupler which reacts with the diazonium salt compound to form a color is 0.1 to 20% by weight.
% By weight (claim 2), whereby:
By applying heat or pressure energy to the recording medium, color development can be performed.

It is preferable that at least one of the diazonium salt compound and the coupler which reacts with the diazonium salt compound to form a color is microencapsulated (claim 3). Coloring can be caused by applying the energy of pressurization, and the threshold value of coloring can be appropriately set.

Further, in the ink jet recording medium according to the present invention, the ink receiving layer contains fine particles, and the colorant in the ink composition is absorbed by the fine particles themselves, or is held in a gap between the fine particles. To form an image
(Claim 4).

On the other hand, a recording method according to the present invention is a recording method in which an ink composition is attached to print on a recording medium, or a droplet of the ink composition is discharged, and the droplet is attached to the recording medium. An ink-jet recording method for performing printing by using the above-described ink-jet recording medium (the recording medium according to claims 1 to 4) (claims 5 and 6).

Further, the present invention is characterized by a recorded matter (Claim 7) recorded by the recording method (Claims 5 and 6). (1) Heating or pressurizing by 10 kg / cm ² or more (Claims 8 to 10), and a recorded matter (Claim 11) formed by coloring by heating or pressurizing in this way. And

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention. The ink jet recording medium according to the present invention is a recording medium for ink jet in which image recording is performed by an ink composition, comprising at least a substrate and an ink receiving layer provided on the substrate. It is characterized in that the ink receiving layer contains at least a diazonium salt compound and a coupler which reacts with the diazonium salt compound to form a color. The content of the diazonium salt compound is preferably in the range of 0.1 to 10% by weight, and the content of the coupler which reacts with the diazonium salt compound to form a color is 0.1 to 20% by weight. It is desirable to set the range. The reason is that if the content exceeds the above-mentioned content, the absorbability of the ink may be deteriorated, and if the content is less than the above-mentioned content, color development due to pressurization or heating is small, and it is difficult to visually discriminate.

The ink jet recording medium according to the present invention can emit a specific color by heating at, for example, 80 ° C. or higher. Further, the ink jet recording medium according to the present invention can be made to emit a specific color by applying a pressure of 10 kg / cm ² or more.

Further, the ink jet recording medium according to the present invention can be configured such that the ink receiving layer contains fine particles. The ink receiving layer can form an image by absorbing the colorant in the ink composition by the fine particles themselves or by holding the colorant in the voids between the fine particles.

The diazonium salt compound used in the present invention,
The coupler which reacts with the diazonium salt compound to form a color is not particularly limited, and any coupler exemplified below can be used.

For example, specific examples of diazonium salt compounds include 2,5-dibutoxy-4-morpholinobenzenediazonium, 2,5-octoxy-4-morpholinobenzenediazonium, and 2,5-dibutoxy-4- (N-
(2-ethylhexanoyl) piperazino) benzenediazonium, 2,5-diethoxy-4- (N- (2-
(2,4-di-tert-amylphenoxy) butyryl) piperazino) benzenediazonium, 2,5-dibutoxy-4-tolylthiobenzenediazonium, 2,5
-Dibutoxy-4-chlorobenzenethiodiazonium,
2,5-diheptyloxy-4-chlorobenzenethiodiazonium, 3- (2-octyloxyethoxy) -4
-Morophorinobenzenediazonium, 4-N, N-dihexylamino-2-hexyloxybenzenediazonium, 4- (N-hexyl-N- (1-methyl-2- (p
-Methoxyphenoxy) ethyl) amino) -2-hexyloxybenzenediazonium and 4-N-hexyl-
A salt of N-tolylamino-2-hexyloxybenzenediazonium can be mentioned.

The acid anion of the diazonium salt compound includes
Hexafluorophosphate salt, tetrafluoroborate salt, 1,5-naphthalene sulfonate salt, perfluoroalkyl carbonate salt, perfluoroalkyl sulfonate salt, zinc chloride salt, tin chloride salt and the like can be used. Preferably, a hexafluorophosphate salt, a tetrafluoroborate salt, and a 1,5-naphthalene sulfonate salt are suitable since they have low water solubility and are soluble in an organic solvent. In the present invention, two different
At least one kind of diazonium salt compound can be mixed and used at an arbitrary ratio.

Known sensitizers may be added as additives. Specific examples include toluenesulfonamide and ethylbenzenesulfonamide. In the present invention, two or more different sensitizers may be used in combination.

The coupler which forms a dye by reacting with a diazonium salt compound is used in the form of fine particles by emulsification dispersion and / or solid dispersion. Specific examples of the coupler include resorcin, flurgurcine, sodium 2,3-dihydroxynaphthalene-6-sulfonate, 1-hydroxy-2-naphthoic acid morpholinopropylamide,
1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxy-6-sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid anilide, 2-hydroxy-3-naphthoic acid ethanolamide, 2-hydroxy- 3-naphthoic acid octylamide,
2-hydroxy-3-naphthoic acid-N-dodecyloxypropylamide, 2-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetoanilide, 2-chloro-5-octylacetoacetanilide, 2,5 -Di-n-heptyloxyacetanilide, 1-phenyl-3-methyl-5
-Pyrazolone, 1- (2'-octylphenyl) -3-
Methyl-5-pyrazolone, 1- (2 ′, 4 ′, 6′-trichlorophenyl) -3-benzamido-5-pyrazolone, 1- (2 ′, 4 ′, 6′-trichlorophenyl)-
3-anilino-5-pyrazolone, 1-phenyl-3-phenylacetamido-5-pyrazolone, 1- (2-dodecyloxyphenyl) -2-methylcarbonatocyclohexane-3,5-dione, 1- (2-dodecyloxy Phenyl) cyclohexane-3,5-dione, N-phenyl-N-dodecylbarbituric acid, N-phenyl-N
-(2,5-dioctyloxyphenyl) barbituric acid and N-phenyl-N- (3-stearyloxy) butyl barbituric acid can be mentioned. These couplers can be used in combination of two or more to obtain a desired color hue.

Further, in order to accelerate the dye-forming reaction, it is common to add a basic compound which has been emulsified and / or solid-dispersed into fine particles. The basic substance includes, in addition to inorganic or organic basic compounds, compounds that release an alkaline substance by decomposition or the like when heated. Representative examples include organic ammonium salts, organic amines, amides, ureas and thioureas and their derivatives, thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidazolines, triazoles , Morpholines,
Examples include nitrogen-containing compounds such as piperidines, amidines, formazines, and pyridines. Specific examples of these include tricyclohexylamine, tribenzylamine, octadecylbenzylamine, stearylamine,
Allyl urea, thiourea, methyl thiourea, allyl thiourea, ethylene thiourea, 2-benzylimidazole, 4
-Phenylimidazole, 2-phenyl-4-methylimidazole, 2-undecylimidazoline, 2,4,5
-Trifuryl-2-imidazoline, 1,2-diphenyl-4,4-dimethyl-2-imidazoline, 2-phenyl-2-imidazoline, 1,2,3-triphenylguanidine, 1,2-dicyclohexylguanidine, 1, 2,
3-tricyclohexylguanidine, guanidine trichloroacetate, N, N'-dibenzylpiperazine, 4,
Mention may be made of 4'-dithiomorpholine, morpholinium trichloroacetate, 2-aminobenzothiazole, and 2-benzoylhydrazinobenzothiazole.
These may be used in combination of two or more.

Further, in the present invention, it is preferable that at least one of the diazonium salt compound and the coupler which reacts with the diazonium salt compound to form a color is microencapsulated in the ink receiving layer. it can.

As a method of microencapsulation, for example, a coacervation method (US Pat. No. 2,800,458)
, An interfacial polymerization method (a method disclosed in Japanese Patent Publication No. 47-1763, etc.), an in-situ polymerization method (a method disclosed in Japanese Patent Application Laid-Open No. 51-9079, etc.) Etc. can be used.

As the wall material of the microcapsules, polyurethane, polyurea, epoxy resin, urea / formalin resin, melamine / formalin resin and the like can be used. Examples of the polyvalent isocyanate compound which is a material for forming a polyurea or polyurethane wall include, for example, 2,4.
-Adducts of tolylene diisocyanate and trimethylolpropane, and adducts of xylylene diisocyanate and trimethylolpropane are mainly used (JP-A-62-212190 and JP-A-4-26189).

As a protective agent for the microcapsules, cellulose powder, starch particles, talc, calcined kaolin, calcium carbonate and the like can be used.

The method of microencapsulation will be described more specifically. For example, it can be produced as follows. As the hydrophobic solvent for forming the core of the microcapsule, an organic solvent having a boiling point of 100 to 300 ° C is preferable. Specifically, alkyl naphthalene, alkyl diphenyl ethane, alkyl diphenyl methane, diphenyl ethane alkyl adduct, alkyl biphenyl,
Examples thereof include phosphoric acid derivatives such as chlorinated paraffin and tricresyl phosphate, maleic esters such as di-2-ethylhexyl maleate, and adipates. These may be used as a mixture of two or more. When the solubility of the diazonium salt compound or coupler in these hydrophobic solvents is not sufficient, a solvent having a lower boiling point can be further used. As the low boiling organic solvent used in combination, an organic solvent having a boiling point of 40 to 100 ° C. is preferable, and specific examples thereof include ethyl acetate, butyl acetate, methylene chloride, tetrahydrofuran, and acetone. These may be used in combination of two or more. When only a solvent having a low boiling point (having a boiling point of about 100 ° C. or lower) is used for the capsule core, the solvent evaporates, so that a so-called coreless capsule in which only the diazonium salt compound or the coupler exists is easily formed.

Depending on the kind of the diazonium salt, it may move to the aqueous phase side during the microencapsulation reaction, and in order to suppress this, an acid anion may be appropriately added to the water-soluble polymer solution in advance. As the acid _{anion, PF 6 -, B (-Rh} ) 4 - [Ph is a phenyl group], ZnC
l _2- , C _n H _{2n + 1} COO- (n is an integer of 1 to 9) and C _p
F _{2p + 1} SO _3- (p is an integer of 1 to 9).

In the present invention, at the time of microencapsulation,
As the compound having active hydrogen used for the polymerization of the isocyanate compound for forming the microcapsule wall,
In general, water is used, but the polyol is added to an organic solvent as a core or a water-soluble polymer solution as a dispersion medium, and is used as a compound having active hydrogen (one of the raw materials of the microcapsule wall). Can be used. Specific examples include propylene glycol, glycerin, and trimethylolpropane. An amine compound such as diethylenetriamine and tetraethylenepentamine may be used instead of or in combination with the polyol.

Examples of the water-soluble polymer for dispersing the oil phase of the microcapsules in the aqueous phase include polyvinyl alcohol and its modified products, polyacrylamide and its derivatives, ethylene / vinyl acetate copolymer, and styrene / anhydrous. Maleic acid copolymer, ethylene / maleic anhydride copolymer, isobutylene / maleic anhydride copolymer, polyvinylpyrrolidone, ethylene / acrylic acid copolymer, vinyl acetate / acrylic acid copolymer, carboxymethylcellulose, methylcellulose, casein , Gelatin, starch derivatives, gum arabic and sodium alginate. It is preferable that these water-soluble polymers do not react with the isocyanate compound or very hardly react with them. For example, those having a reactive amino group in the molecular chain such as gelatin should be deactivated in advance. is necessary.

In the present invention, the ink receiving layer comprises a binder and a pigment on a substrate, and further, if necessary, a dye fixing agent (waterproofing agent), a fluorescent whitening agent, a surfactant, a defoaming agent,
It is formed using a coating liquid in which various additives such as a regulator, a fungicide, an ultraviolet absorber, and an antioxidant are mixed.

Examples of the binder include starch derivatives such as oxidized starch, etherified starch, and phosphated starch; cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; casein, gelatin, soy protein,
Polyvinyl alcohol or a derivative thereof; conjugated diene copolymer latex such as polyvinyl pyrrolidone, maleic anhydride resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer; acrylate or methacrylate ester polymer or copolymer An acrylic polymer latex such as an acrylic polymer such as a polymer;
Vinyl-based polymer latex such as ethylene-vinyl acetate copolymer; or functional group-modified polymer latex with a monomer containing a functional group such as carboxy group of these various polymers; Thermosetting resin such as melamine resin and urea resin Water-based adhesives; acrylic esters such as polymethyl methacrylate; polymers or copolymers of methacrylic esters; synthetic resin-based adhesives such as polyurethane resins, unsaturated polyester resins, vinyl chloride vinyl acetate copolymers, polyvinyl butyral, and alkyd resins Agents and the like.

As the pigment, one or more known white pigments can be used. For example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, thisan white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate , Synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudo-boehmite, aluminum hydroxide, lithopone, zeolite, hydrohaloysite, white inorganic pigments such as magnesium hydroxide, styrene-based plastic pigment, acrylic-based plastic pigment, polyethylene, Organic pigments such as melamine resin and urea resin are exemplified.

In the present invention, as the recording medium provided with the ink receiving layer, a conventionally known base material, for example,
There are paper, synthetic paper, plastic film and the like. Paper as a recording medium is a sheet containing a fibrous substance and, if necessary, a filler, and any of those which have been made within the above range by a suitable sizing agent by a conventionally known acidic papermaking method or neutral papermaking method. Can also be used.

The fibrous material constituting the paper is mainly wood pulp typified by LBKP and NBKP, but various synthetic fibers and glass fibers may be mixed if necessary.
As a plastic film as a recording medium, a conventionally known recording medium is used regardless of whether it is transparent or opaque. As the material, a polyester resin, a triacetate resin, an acrylic resin, a polycarbonate resin, a polyimide resin, a polyurethane resin, an epoxy resin, cellophane, celluloid, and the like, which are conventionally known materials, can be used. .

[0035]

Next, examples of the present invention will be described together with comparative examples.
The present invention will be specifically described. (Example) ・ Basic coating liquid (composition) of ink receiving layer Silica fine particles (Mizukasil P-50: manufactured by Mizusawa Chemical) 15 parts by weight Polyvinyl alcohol (PVA217: manufactured by Kuraray) 15 parts by weight Ion exchange water 170 parts by weight

<Diazonium Salt Compound-Containing Microcapsule Dispersion (Solution A)> As a diazonium salt compound, 3.5 parts of the following compound (A-1) and 0.9 part of compound (A-2) are dissolved in 16.4 parts of ethyl acetate, and 7.3 parts of isopropyl biphenyl, which is a high boiling point solvent, and 2.5 parts of dibutyl phthalate were added, and mixed by heating.

[0037]

Embedded image

[0038]

Embedded image

To the above mixture, 7.5 parts of xylylene diisocyanate / trimethylolpropane adduct (Takenate D110N, 75% by weight ethyl acetate solution, manufactured by Takeda Pharmaceutical Co., Ltd.) was added as a capsule wall material, and the mixture was stirred uniformly. Separately, Scraph
77 parts of a 6% by weight aqueous gelatin solution to which 0.36 parts of AG-8 (manufactured by Nippon Seika Co., Ltd.) was added was prepared, and a mixed solution (solution) of the diazonium salt compound was added, followed by emulsification and dispersion with a homogenizer.

After 20 parts of water was added to the obtained emulsion to homogenize it, an encapsulation reaction was carried out at 40 ° C. with stirring for 3 hours. Thereafter, the liquid temperature was lowered to 35 ° C., and 6.5 parts of ion-exchange resin Amberlite IRA68 (manufactured by Organo) and Amberlite IRC5
Then, 13 parts of 0 (manufactured by Organo) was added, and the mixture was further stirred for 1 hour. Thereafter, the ion exchange resin is filtered, and then the capsule liquid 10
0.4 part by weight of a 1% by weight aqueous solution of hydroquinone was added and stirred. Thus, a capsule solution of the diazonium salt compound (hereinafter, referred to as “solution A”) was obtained. In addition,
The average particle size of the capsule was 1.1 μm.

<Coupler emulsified dispersion (liquid B)> As couplers, 2.4 parts of 2,5-di-n-heptyloxyacetanilide and 2.5 parts of triphenylguanidine, 3.3 parts of 4- (2-ethylhexyloxy) phenylsulfonamide, 1.7 parts of 4-n-pentyloxyphenylsulfonamide, 5.0 parts of 4,4 ′-(m-phenylenediisopropylidene) diphenol, ethyl acetate
After dissolving in 8.0 parts and adding 1.0 part of Pionin A41C (manufactured by Takemoto Yushi Co., Ltd.), the mixture was heated and uniformly mixed. This mixture was added to a separately prepared 75.0 parts of a 10% by weight aqueous solution of gelatin (# 750 gelatin, manufactured by Nitta Gelatin Co., Ltd.) and emulsified and dispersed by a homogenizer. The remaining ethyl acetate was evaporated from this emulsion to obtain a target emulsified dispersion (hereinafter, referred to as "liquid B").

<Preparation of Ink-Receiving Layer Coating Solution> The basic coating solution for the ink-receiving layer: 100 g, the A solution: 5 g, and the B solution:
3 g were mixed well to obtain an ink receiving layer coating liquid. <Preparation of inkjet recording medium> Basis weight: 100 g / m ²
On a high quality paper, apply the ink receiving layer coating solution with a dry film thickness of 20 μm.
m, and dried to obtain an inkjet recording medium.

(Comparative Example) For comparison, in the above-mentioned example, "Solution A" blended in the basic coating liquid of the ink receiving layer was used.
An ink jet recording medium was produced in the same manner as in the above example except for the “liquid B”. That is, basis weight: 10
0 g / m ² of high quality paper is coated with the basic coating liquid of the ink receiving layer used in the above example so that the dry film thickness becomes 20 μm,
After drying, a recording medium for inkjet according to a comparative example was produced.

The following Examples and Comparative Examples were subjected to the following printing evaluation tests, and the evaluation results are shown in Table 1.

(Print Evaluation Test) As a print test machine, an ink jet printer “MJ-930” manufactured by Seiko Epson Corporation was used.
C "was used. The printing was carried out by using the above-mentioned ink jet printer on the ink jet recording media obtained in the examples and comparative examples, and each color of black, yellow, magenta, and cyan was 0.7 density. After the ink-jet printing, the ink-jet printing was allowed to dry for 10 minutes, and then the "heat recording" or "pressure recording" was performed on each of the ink-jet printed recording media by the following method. The "state of color development" was examined by the judgment method shown in FIG.

Heating Recording Method An iron having a surface temperature of 150 ° C. was pressed against the recording medium on which ink-jet printing was performed for 3 seconds. Pressure Recording Method A load of 100 kg / cm ² was applied to the inkjet-printed recording medium for 60 seconds.

Judgment Method The "A" indicates that the heating or pressurized coloring marks on the recording medium on which ink-jet printing has been performed can be clearly judged visually. B "and" C when it cannot be visually determined "are indicated as" C ".

[0048]

[Table 1]

As is evident from Table 1, in Examples of the present invention, coloring traces due to heating and pressing could be visually observed. On the other hand, in the comparative example, heating,
No coloring marks appeared in any of the pressurized cases.

[0050]

As described above in detail, the recorded matter by the recording method using the inkjet recording medium according to the present invention can be fixed by applying heating or pressurizing energy to the recorded matter after inkjet recording. Since color development occurs by the above-mentioned heating or pressurization, it is very easy to determine whether the recording is a counterfeit or a genuine one by the heating or pressurization. Further, by using the color to be developed and the degree of heating or pressurizing to be used as the specific hidden information, it is possible to easily perform a tracking search on the forged copy printed matter. Further, the recording method according to the present invention can insert specific hidden information by the ink composition, so that a special device for recording the hidden information is not required, and a printer using a general ink jet recording method can be used. It is a very useful recording method that can be applied and facilitates traceability of counterfeit copies.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI theme coat ゛ (reference) // D21H 21/48 B41J 3/04 101Y F term (reference) 2C056 EA21 FC02 FC06 FD07 2H086 BA01 BA02 BA05 BA15 BA31 BA33 BA45 4D075 CA35 CB08 CB40 DA04 DB18 DC27 4L055 AG18 AG35 AG36 AG64 AG96 AH02 AH03 AH37 AH50 AJ08 EA20 EA23 EA32 GA09 GA12 GA14 GA45

Claims (11)

[Claims] 1. An inkjet recording medium on which an image is recorded with an ink composition, comprising at least a substrate and an ink receiving layer provided on the substrate, wherein the ink receiving layer has Characterized by containing at least a diazonium salt compound and a coupler which reacts with the diazonium salt compound to form a color. 2. The content of the diazonium salt compound is 0.1 to 10% by weight, and the content of a coupler which reacts with the diazonium salt compound to form a color is 0.1 to 20% by weight. The inkjet recording medium according to claim 1, wherein: 3. The ink jet recording medium according to claim 1, wherein at least one of the diazonium salt compound and a coupler that reacts with the diazonium salt compound to form a color is microencapsulated. 4. The image forming apparatus according to claim 1, wherein the ink receiving layer contains fine particles, and the colorant in the ink composition is absorbed by the fine particles themselves or is held in a space between the fine particles to form an image. The inkjet recording medium according to any one of claims 1 to 3, wherein: 5. A recording method for printing on a recording medium by adhering an ink composition, wherein the inkjet recording medium according to claim 1 is used as an inkjet recording medium. Characteristic recording method. 6. An ink jet recording method for discharging ink droplets of an ink composition and attaching the liquid droplets to a recording medium to perform printing, wherein the ink jet recording medium is used.
5. An ink jet recording method, comprising using the ink jet recording medium according to any one of items 1 to 4. 7. A recorded matter recorded by the recording method according to claim 5. Description: 8. A recording method characterized in that the recorded matter according to claim 7 is colored by heating or pressing. 9. The recording method according to claim 8, wherein the color is developed by heating at 80 ° C. or higher. 10. The recording method according to claim 8, wherein the color is developed by applying a pressure of 10 kg / cm ² or more. 11. A recorded matter recorded by the recording method according to claim 8. Description: