JP2001088445A - Image recording medium and image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording medium used for multi-coloring with high sensitivity and utilizing the heat mode recording method using laser. SOLUTION: A non-silver salt image recording medium is provided with a coloring layer containing an acid generating agent represented by a formula I generating an acid by the action of heat or acid and a compound generating the intermolecular reaction or the intermolecular reaction by the action of the aid and also generating changes on a 360-900 nm absorption zone, and a plurality of coloring layers are formed. In the formula I, W1 represents a residual radial of acid represented by W1OH, and P1 represents a substituent to be separated by the action of heat or acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording medium utilizing a coloring (or decoloring) reaction accelerated by an acid catalyst, and more particularly, to a high sensitivity using an acid and / or dye multiplication system. And an image recording medium having good storability. Furthermore, the present invention
An acid generator that generates an acid by the action of heat or an acid,
The present invention relates to an image recording medium having high sensitivity and good storability, having a color-forming layer containing a compound that undergoes an absorption change by a reaction with an acid, and having a plurality of color-forming layers, and an image recording method using the same.

[0002]

2. Description of the Related Art A heat-sensitive recording material expresses an image area and a non-image area as a temperature difference distribution, and includes a color transfer reaction between two components due to a melt transfer or sublimation transfer of a colorant, heat melting or capsule destruction, and a phase transition. Many schemes have been devised, such as changes in optical properties. This type of thermal recording medium is widely used as an output material for various printers, word processors, facsimile machines, etc. because of its advantages that a recorded image can be obtained by a dry and simple system and that it is maintenance-free. In recent years, with the progress of laser recording devices, applications to optical disks and plate making materials are being studied.

Conventionally, silver halide photographic materials requiring wet processing have been used as plate making materials. However, due to the demand for simplification of processing steps and the problem of environmental pollution caused by processing solutions, development of dry processing has been required. Desirably, several technical proposals have been made in recent years using the thermal recording method. From the viewpoint of resolution, image recording using a laser is preferable. For example, a method called dye abrasion using a high-power laser has been developed, and the recording material is disclosed in
-164755, -149063, 7-149
No. 065 etc., an image forming apparatus is disclosed in Japanese Patent Application Laid-Open No. 8-48053.
And No. 8-72400. In this system, a recording material having a dye composition composed of an image dye applied on a support, a substance having absorption in a laser wavelength range (infrared absorbing substance) and a binder is irradiated with laser from the dye layer side. Image recording is performed.
The energy provided by the laser causes a sharp local change in the imaging layer at the spot where the laser beam hits the material, thereby driving the material out of the layer.
In such a dye ablation method, a high-power laser is indispensable in order to increase the efficiency of removing the dye at the laser exposure site, and a dust collector is required to collect the removed dye. there were.

As a method that does not require a dust collector, a description of an ablation transfer type image recording method using a laser as a heat source is disclosed in US Pat. No. 5,171,650. In this system, a dye donor sheet containing a dynamic release layer overcoated with an ablative carrier topcoat is used, and the image is transferred to another adjacently aligned receiving sheet. For this reason, there has been a problem that a sheet that has become unnecessary after image recording becomes a waste material. Also in this case, a high-output laser was indispensable to enhance the transfer efficiency. As described above, the conventional thermal recording method using laser ablation requires a high-output laser, and has a problem that dust and waste materials cannot be avoided.

On the other hand, as a thermal recording method using laser and not involving ablation, a system called "dry silver" has been developed as disclosed in JP-A-6-1947.
No. 81, etc. In this system, laser recording is performed on a recording material containing a silver source that can be thermally reduced, a reducing agent for silver ions, and a photothermal conversion dye. This was insufficient for practical performance.

Further, as another thermal recording system using a laser, US Pat. Nos. 4,602,263 and 4,826,976 describe compounds whose absorption changes due to thermal decomposition of carbamate. And the 5th and 2nd
No. 43,052 describes a compound which develops yellow color by thermal decomposition of a t-butoxycarbonyl group introduced into a hydroxyl group. These methods utilize an irreversible single-molecule reaction, and are preferable for recording images in an extremely short time using a laser. However, the sensitivity is insufficient and further enhancement of sensitivity is desired. Sensitivity can be increased by coexistence of an acid catalyst, but storage stability is a problem.

As a method for forming a UV mask image (360 nm to 420 nm; corresponding to an exposure light source for a PS plate) commonly used for plate making materials, no practical proposal has been made in a heat mode system using a laser.

On the other hand, US Pat. Nos. 5,286,612, 5,395,736, and 5,441,850,
JP-T-8-503081 and JP-T-8-503082 disclose compounds which generate a superacid having a pKa <0 by the action of actinic radiation.
It describes a secondary acid generator that generates a secondary acid in the presence of a super strong acid, and a recording material containing a compound that changes color upon contact with the secondary acid. Although this method is an effective method in terms of increasing the sensitivity of a recording material, the generation of a secondary acid from a secondary acid generator described in the patent is catalyzed only by a super strong acid generated from a super strong acid precursor. According to the patent gazette, about 20 molecules of super strong acid per molecule are used.
It is said that the decomposition of the secondary acid precursor is catalyzed. However, since the generated secondary acid has no catalytic ability, it cannot be expected to increase the sensitivity by the so-called rat-based acid multiplication. As methods for solving these problems, JP-A-11-180048 and 11-1
No. 81031 discloses a high-sensitivity image recording material. Here, UV, 420 nm,
Although materials that develop color for each visibility are shown, a decrease in sensitivity was observed when simultaneously developing multiple colors, and improvement of the sensitivity was desired.

[0009]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a multi-color coloring with high sensitivity and to prevent ablation even when a heat mode image recording system using a laser is used. Low-power laser recording (especially 360-4 which is indispensable as a mask film for plate making)
It is an object of the present invention to provide a novel image recording medium and an image recording method which can perform image recording corresponding to 20 nm, do not require a separate image receiving sheet, and have excellent storage stability. A second object of the present invention is to provide a multilayer image recording material which develops (or decolorizes) only by the action of a catalytic amount of acid or heat.

[0010]

The object of the present invention has been attained by the present invention as described below. An acid generator represented by the following general formula (1), which generates an acid by the action of heat or an acid on a support, and an intramolecular or intermolecular reaction caused by the action of an acid, causing 360 to 900
A non-silver salt image recording medium having a coloring layer containing a compound that causes a change in the absorption region of nm, and wherein a plurality of coloring layers are present. Formula (1) W in ¹ OP ¹ Formula, W ¹ represents a residue of an acid represented by W ¹ OH, P ¹
Represents a substituent which is released by the action of heat or an acid. The image recording medium according to claim 1, wherein the acid generator represented by the general formula (1) is a compound selected from the following general formulas (2) to (4). General formula (2)

[0011]

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In the formula, R ¹ represents an electron-withdrawing group having a Hammett σ _p value larger than 0. R ² represents an alkyl group. R
³ represents a group capable of leaving under the action of heat or an acid. W ¹
Has the same meaning as in formula (1). General formula (3)

[0013]

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Where R^Four, R^Five, R⁶Is a hydrogen atom, al
Represents a kill group or an aryl group;¹Is the general formula
It is synonymous with (1). General formula (4) P^Two-XLC (R⁷) (R⁸) -OW¹ Where P^TwoRepresents a substituent that is released by the action of heat or an acid.
You. X is O, S, NR ⁹(R⁹Is a hydrogen atom or replaceable
Functional group), or CR^TenR¹¹(R^TenAnd R¹¹Is
Represents a hydrogen atom or a substitutable group.
May be included). L represents a linking group. R⁷You
And R⁸Represents a hydrogen atom or a substitutable group.
May be different. W¹Is the same as in general formula (1)
Righteous. Has the function of generating acid by the action of heat or acid
Absorption of 360-900 nm by the action of acid
Includes polymers that combine partial structures that cause changes in
A non-silver salt image recording medium having a coloring layer having
An image recording medium comprising a plurality of color layers. The polymer described is a polymer represented by the following general formula (5).
The image recording medium according to the above, which is a rimmer.
body. General formula (5)-(A)_x-(B)_y-(C)_zA in the formula is a function of generating an acid by the action of heat or an acid
Of at least one vinyl monomer having
Represents a repeating unit obtained by
Partial structure causing a change in the absorption range of 360 to 900 nm.
Weight of at least one vinyl monomer having
And C represents A and
At least one vinyl monomer copolymerizable with B
Represents a repeating unit obtained by polymerization of
And z represent% by weight, and 1 ≦ x ≦ 99 and 1 ≦
It represents y ≦ 99, 0 ≦ z ≦ 98, and x + y + z = 100. The image forming medium according to the above, which comprises an infrared absorbing dye.
Form body by irradiating infrared laser
An image forming method comprising: Characterized by having an intermediate layer between the color-forming layers
An image recording medium according to any one of the above.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The present invention relates to a recording medium for forming an image, containing an acid generator that generates an acid by the action of heat or an acid, and a compound that changes the absorption range of 360 to 900 nm by an intramolecular or intermolecular reaction by the action of the acid. It is about. The compound represented by the general formula (1) has a function of generating an acid by the action of heat or an acid. In the acid generator represented by the general formula (1), W ¹ represents a residue of an acid (sulfonic acid, carboxylic acid, phosphoric acid, phenol, etc.) represented by W ¹ OH. W ¹ OH is preferably an acid having a pKa smaller than 3, and preferred examples thereof include arylsulfonic acid, alkylsulfonic acid, carboxylic acid having an electron-withdrawing group, arylphosphonic acid, and alkylphosphonic acid. P ¹ represents a substituent capable of splitting off by the action of heat or acid, W ¹ OP ¹ with the separation of P ¹
An acid represented by W ¹ OH is generated from the acid generator represented by Examples of such a substituent include an alkyl group having a hydrogen atom at the β-position (eg, a tetrahydropyranyl group, a tetrahydrofuranyl group, a t-butyl group, a cyclohexyl group, a 4,5-dihydro-2-methylfuran-5-yl group) , 2-cyclohexenyl group, etc.), an alkoxycarbonyl group having a hydrogen atom at the β-position (for example, t-butoxycarbonyl group, cyclohexyloxycarbonyl group, 2- (2-methyl) butoxycarbonyl group, 2- (2-phenyl) propyloxy Carbonyl group, 2-chloroethoxycarbonyl group, etc.), silyl group (for example, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, phenyldimethylsilyl group, etc.), or these groups, or acetal, ketal, thioketal, pinacol , Decompose the epoxy ring Substituents which are released to gold (for example, a group substituted by W ¹ OH in the description of the following general formulas (2) to (4)) are exemplified. General formula (1)
Examples of the acid generator represented by are, for example, trifluoroacetic acid (α-phenylisopropyl) ester, trifluoroacetic acid t-butyl ester, toluenesulfonic acid cyclohexyl ester, p-nitrobenzoic acid triethylsilyl ester, p-nitrobenzoic acid tetrahydrogen Pyranyl esters, poly (4-vinyl-1-t-butoxycarbonyloxy-2-nitrobenzene), poly (cyclohexyl 4-vinylbenzenesulfonate) and the like can be mentioned, but in the present invention, the viewpoints of acid generating ability and storage stability. And the compounds represented by formulas (2) to (4) are preferred.

In the general formula (2), R ¹ represents an electron-withdrawing group having a Hammett σ _p value of more than 0, and R ¹ is preferably an acyl group (eg, acetyl, propanoyl, 2-methylpropanoyl, pivaloyl, Benzoyl, naphthoyl), a cyano group, an alkylsulfonyl group (methanesulfonyl, ethanesulfonyl, benzylsulfonyl, t-butylsulfonyl, etc.) or an arylsulfonyl group (benzenesulfonyl, etc.). R
¹ is more preferably an acyl group. R ² represents an alkyl group (methyl, ethyl, isopropyl, octyl, dodecyl, etc.). R ² is preferably a group having 6 or less carbon atoms. R ³ represents a group capable of leaving by heat or an acid, and is preferably a secondary or tertiary alkyl group having a hydrogen atom at the β-position (t-butyl, 1,1-dimethylpropyl, 1,1,3,3 -Tetramethylbutyl, cyclohexyl, 2-cyclohexenyl, etc.), silyl groups (trimethylsilyl, t-butyldimethylsilyl, etc.),
Or an alkoxymethyl group (methoxymethyl, octyloxymethyl, tetrahydropyranyl, tetrahydrofuranyl, 4,5-dihydro-2-methylfuran-5
And the like). R ³ is preferably a secondary or tertiary alkyl group having a hydrogen atom at the β-position. These groups represented by R ^{1 to} R ³ may further have a substituent. W ¹ has the same meaning as in formula (1). Next, the compound represented by formula (3) will be described.
In the general formula (3), R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom, an alkyl group (eg, methyl, ethyl, isopropyl, t-butyl, octyl, dodecyl) or an aryl group (eg, phenyl, naphthyl). Represents R ⁴ ,
R ⁵ and R ⁶ may further have a substituent. R ⁴ and R
⁵ , R ⁴ and R ⁶ or R ⁵ and R ⁶ may be bonded to each other to form a ring. W ¹ has the same meaning as in formula (1). The compounds represented by formulas (2) and (3) are disclosed in
Can be synthesized according to the method described in JP-A-248561.

The compound which releases an acid by a completely different mechanism from the above has at least one substituent removed by the action of heat or an acid, and an intramolecular nucleophilic substitution reaction following the removal of the substituent. And a compound which generates an acid. A preferred form is a compound represented by the general formula (4). General formula (4) P ² -X-LC (R ⁷ ) (R ⁸ ) -OW ^{1 In the} formula, P ² represents a substituent removed by the action of heat or an acid. X is O, S, NR ⁹ (R ⁹ represents a hydrogen atom or a substitutable group), or CR ¹⁰ R ¹¹ (R ¹⁰ and R ¹¹
Represents a hydrogen atom or a substitutable group, which may be the same or different). L represents a linking group. R ⁷
And R ⁸ represent a hydrogen atom or a substitutable group, and may be the same or different. W ¹ has the same meaning as in formula (2). The substituent P ² removed by the action of heat or an acid is introduced into a nucleophilic group such as a hydroxyl group, a mercapto group, an amino group, or a carbon atom to prevent an intramolecular nucleophilic substitution reaction during storage or in a non-image area. In the part, the substituent is decomposed and eliminated by the action of heat or an acid, so that an acid can be generated by an intramolecular nucleophilic substitution reaction. Useful substituents represented by P ² include, when introduced into an oxygen atom, an alkoxycarbonyl group (for example, t-butoxycarbonyl group, isopropyloxycarbonyl group, 1-phenylethoxycarbonyl group, 1,1-diphenylethoxy group). Carbonyl group, 2-cyclohexeneoxycarbonyl group, etc.), alkoxymethyl group (for example, methoxymethyl group,
Ethoxymethyl group, n-octyloxymethyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 4,5
-Dihydro-2-methylfuran-5-yl group, etc.), silyl group (for example, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, phenyldimethylsilyl group, etc.), and β
Secondary or tertiary alkyl group having a hydrogen atom at position (for example, t-butyl, 1,1-dimethylpropyl,
Preferred examples include 1,1,3,3-tetramethylbutyl, cyclohexyl, 2-cyclohexenyl, and the like. Among those introduced into a sulfur atom, an alkoxymethyl group (eg, isobutoxymethyl group, tetrahydropyranyl group, etc.), an alkoxycarbonyl group (eg, benzyloxycarbonyl group, p-methoxybenzyloxycarbonyl group, etc.), an acyl group (eg, acetyl Groups, a benzoyl group, etc.), and a benzyl group (eg, a p-methoxybenzyl group, a bis (4-methoxyphenyl) methyl group, a triphenylmethyl group, etc.) are preferred examples. Among those introduced into a nitrogen atom, alkoxycarbonyl groups (for example, t-butoxycarbonyl group, cyclohexyloxycarbonyl group, 2- (2-methyl) butoxycarbonyl group, 2- (2-phenyl) propyloxycarbonyl group, 2-chloroethoxycarbonyl Groups), an acyl group (eg, an acetyl group, a benzoyl group, a 2-nitrobenzoyl group, a 4-chlorobenzoyl group, a naphthoyl group, etc.) or a formyl group. A tertiary alkoxycarbonyl group (such as a t-butoxycarbonyl group) is preferably introduced as a carbon atom.

In the intramolecular nucleophilic substitution reaction following the removal of these substituents, a form in which a 5- to 10-membered ring is formed is preferred, and a 5- or 6-membered ring is particularly preferred. The linking group L is preferably selected so as to form a ring of these sizes.

The acid generator of the present invention may form a polymer by linking a plurality of polymerizable groups introduced at substitutable positions. When applied to an image recording medium utilizing the fact that the hue changes due to the action of an acid described below, the coatability is imparted without using a separate binder by forming a polymer, so that the image recording layer can be used. This is advantageous for thinning. The molecular weight of the polymer is preferably in the range of 1,000 to 1,000,000, particularly preferably 2,000 to 3
This is the case when it is in the range of 10,000. In this case, it may be a homopolymer or a copolymer with another monomer. When the compound of the present invention is used as a polymer, the number of carbon atoms may exceed the definition of carbon number described in the above description. Hereinafter, specific examples of the compounds represented by formulas (1) to (4) of the present invention are shown, but the present invention is not limited thereto.

[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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The addition amount of these acid generators varies depending on the type of the compound having a change in absorption, but is generally preferably in the range of 0.001 to 20 equivalents, particularly preferably, with respect to the compound having a change in absorption. Is the case of 0.01 to 5 equivalents.

In the present invention, a compound that changes the absorption band at 360 to 900 nm by an intramolecular or intermolecular reaction by the action of an acid is stable as long as it is stored under neutral to basic conditions. When the acid acts, the activation energy of the intramolecular or intermolecular reaction decreases,
It is a compound that easily undergoes a reaction by heating to cause a change in absorption in the above range. At this time, the heating temperature for forming an image is preferably from 60 to 200 ° C, particularly preferably from 80 to 140 ° C.
The compound having such an absorption change may be a single compound or may be composed of two or more components. For example, a compound (for example, 9,10-distyrylanthracene and maleic anhydride, tetraphenylcyclopentadiene and an acrylate ester) that forms a decolorized image in the area by a Diels-Alder reaction, A compound that forms a color image (for example, an adduct of 9,10-distyrylanthracene and maleic anhydride, an adduct of diphenylisobenzofuran and acrylamide, etc.), a conjugated system is expanded by β-hydrogen elimination, and a color image is formed in the region. Compounds to be formed (for example, 1-acetoxy-1,2-diarylethane,
1-sulfoxy-1,2-diarylethane, etc.), a combination of an aldehyde and an active methylene compound which forms a color image in the region by dehydration condensation (for example, a photographic 4 equivalent magenta coupler and p-methoxycinnamaldehyde) or an acid. Compounds having an amino group or a hydroxyl group substituted by a substituent whose decomposition or elimination is promoted by the action in a molecule, and the absorption in the above absorption range is changed by the removal of the substituent. A basic leuco dye or the like which develops color instantly upon contact with an acid can also be used in the image forming medium. However, such a compound acts as a base and uses microcapsules to inhibit the acid growth process. It is necessary to keep it separate from the acid generator and the acid multiplying agent by coating or applying it to another layer.

In the present invention, a compound whose absorption is changed by the decomposition or elimination of a substituent of an amino group or a hydroxyl group by the action of an acid is particularly useful. Examples of such a substituent of the amino group include an alkoxycarbonyl group (for example, t-butoxycarbonyl group, cyclohexyloxycarbonyl group, 2- (2-methyl) butoxycarbonyl group, 2- (2-phenyl) propyloxycarbonyl group, 2-chloro Preferred examples include an ethoxycarbonyl group), an acyl group (eg, an acetyl group, a benzoyl group, a 2-nitrobenzoyl group, a 4-chlorobenzoyl group, and a naphthoyl group), and a formyl group. From the viewpoint of heat sensitivity, an alkoxycarbonyl group having a hydrogen atom at the β-position is particularly useful. Such compounds include, for example, U.S. Pat.
Nos. 602,263, 4,826,976, etc., which provide a heat-sensitive recording material having higher sensitivity and excellent storage stability when combined with the thermal acid generator and the acid multiplying agent of the present invention. be able to. Examples of the substituent of the hydroxyl group which is decomposed or eliminated by the action of an acid include a secondary or tertiary alkoxycarbonyl group having a hydrogen atom at the β-position (for example, t-butoxycarbonyl group, isopropyloxycarbonyl group, 1-phenylethoxycarbonyl group) ,
1,1 diphenylethoxycarbonyl group, 2-cyclohexeneoxycarbonyl group, etc.), silyl group (for example, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, phenyldimethylsilyl group, etc.), Alkoxymethyl group (for example, methoxymethyl group, ethoxymethyl group, 1-methoxyethyl group, 1-phenoxyethyl group, 2- (2-methoxypropyl) group, etc.) and secondary or tertiary alkyl group having a hydrogen atom at the β-position (For example, tetrahydropyranyl group, tetrahydrofuranyl group, 4,5-dihydro-2
-Methylfuran-5-yl group, t-butyl group, 2-cyclohexenyl group and the like) are preferred examples,
In the present invention, a secondary or tertiary compound having a hydrogen atom at the β-position is particularly preferred.
Grade alkoxycarbonyl groups are preferred. No. 5,243,052 or JP-A-9-2536 discloses compounds whose absorption is changed by decomposition of a hydroxyl group substituent.
There is a description example in No. 0 and the like. Below 360-action by the action of acid
Specific examples of the compound that causes a change in the absorption region at 900 nm are shown, but the present invention is not limited to these.

[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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The image recording medium of the present invention is generally 360 to 900 by the action of the acid generator, acid multiplying agent and acid.
It is prepared by applying a composition that changes the absorption range in nm on a support. At this time, a binder is usually coexisted, unless one of these is a polymer or an amorphous having good coatability. When the binder does not need to be used, there is an advantage that the film thickness can be easily reduced and a sharp image can be obtained. When a binder is used, gelatin, casein, starches, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, polyacrylamide, a water-soluble binder such as ethylene-maleic anhydride copolymer, and polyvinyl butyral, triacetyl cellulose, polystyrene, acrylic Any water-insoluble binder such as a methyl acid-butadiene copolymer and an acrylonitrile-butadiene copolymer can be used. Further, in the present invention, a compound in which color is changed or decolored by the action of an acid to change the hue and an acid generator are made into a copolymer, so that an acid is generated in the immediate vicinity of the compound in which the hue changes. High sensitivity can be expected. In addition, by controlling the diffusion of molecules by polymerization, there is a possibility that the cut-off and preservation of images can be improved. These characteristics are particularly preferable for applications requiring high image quality, such as graphic arts films. A preferred form of such a compound is represented by the general formula (5). The general formula (5) will be described. In the general formula (5), A represents a repeating unit obtained by polymerization of at least one kind of vinyl monomer having a function of generating an acid by the action of heat or an acid. As the compound having such a function, the compounds represented by the aforementioned general formulas (1) to (1)
It can be obtained by introducing a polymerizable group into any part of the compound represented by (4). When the polymer having a thermal acid generating function of the present invention is applied to a laser heat mode type image recording medium, it is useful without adding an acid generator separately. Specific examples of the vinyl monomer forming A in the general formula (5) are shown below, but the invention is not limited thereto. These compounds can be synthesized in the same manner as in the method described in JP-A-8-248561.

[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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In the general formula (5), B represents a repeating unit obtained by polymerization of at least one kind of vinyl monomer having a partial structure in which the absorption range from 360 to 900 nm is changed by the action of an acid. Compounds that cause an absorption change by the action of an acid are as described above,
In the above structure, a polymerizable group is introduced at a substitutable position. Specific examples are shown below, but the present invention is not limited to these.

[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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The vinyl monomer represented by B is used by itself as a “compound which changes the absorption band at 360 to 900 nm by the action of an acid” (B- in the Examples).
14). C in the general formula (5) represents a repeating unit obtained by polymerization of at least one kind of vinyl monomer capable of forming a copolymer together with A and B, and controls polarity, glass transition temperature, and the like. Thus, storage stability, coloring activity and the like can be controlled. Such vinyl monomers may be used in combination of two or more. Preferred examples include acrylates, methacrylates, acrylamides,
Examples include styrene and vinyl ether. Specific examples of the monomer forming C are shown below, but the present invention is not limited thereto.

[0054]

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[0055]

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[0056]

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[0057]

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In the general formula (5), x, y and z represent% by weight of each composition. x, y and z are respectively 1 ≦ x ≦ 99,
1 ≦ y ≦ 99, 0 ≦ z ≦ 99, and x + y + z = 100
It is. It is preferable that the relation of 0.01y <x ≦ 10y be satisfied, and particularly preferable that the relation of 0.1y ≦ x ≦ 5y be satisfied. z is preferably 0 ≦ z ≦ 50.

The molecular weight of the polymer represented by the general formula (5) is preferably in the range of 1,000 to 1,000,000, particularly preferably in the range of 2,000 to 100,000. The polymer may be in any form such as a random copolymer, an alternating copolymer and a block copolymer, but a random copolymer which is easily synthesized is generally used.

The monomers forming A, B, C in the polymer represented by the general formula (5) and x, y, z
Are shown, but the present invention is not limited to these.

[0061]

[Table 1]

The polymer of the present invention can be synthesized by various polymerization methods such as solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization,
It can be carried out by emulsion polymerization. The method of initiating polymerization includes a method using a radical initiator, a method of irradiating light or radiation, and the like. These polymerization methods and the method of initiating the polymerization are described in, for example, T. Tsuruta, “Polymer Synthesis Method” Revised Edition (Nikkan Kogyo Shimbun, 1971), Takatsu Otsu, Masayoshi Kinoshita, “Experimental Method of Polymer Synthesis” Published in 1972,
It is described on pages 124-154.

Among the above polymerization methods, a solution polymerization method using a radical initiator is particularly preferred. Solvents used in the solution polymerization method include, for example, ethyl acetate, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, benzene, toluene, acetonitrile, Various organic solvents such as methylene chloride, chloroform and dichloroethane may be used alone or as a mixture of two or more thereof, or may be used as a mixed solvent with water.

The polymerization temperature must be set in relation to the molecular weight of the polymer to be formed, the type of initiator, and the like, and can be from 0 ° C. or lower to 120 ° C. or higher.
Polymerization is carried out in the range of 0 ° C. In the present invention, it is preferable to carry out the polymerization at a temperature in the range of 30 to 90 ° C. because the monomer forming the site A in the general formula (5) may decompose at a high temperature.

Examples of the radical initiator used for the polymerization include 2,2′-azobisisobutyronitrile,
Such as 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-amidinopropane) dihydrochloride, and 4,4'-azobis (4-cyanopentanoic acid) Preferred are azo-based initiators and peroxide-based initiators such as benzoyl peroxide, t-butyl hydroperoxide, and potassium persulfate (for example, redox initiators may be used in combination with sodium bisulfite). In the present invention, the initiator (for example, 2,2'-azobis (2,4-dimethylvaleronitrile)) or 2,2'-azobis (4-methoxy-2,
4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate), 2,2'-azobis [2- (3,4,5,6-tetrahydropropane)
Dihydrochloride] and the like are particularly preferred.

The amount of the polymerization initiator used can be adjusted according to the polymerizability of the monomer and the required molecular weight of the polymer, but is in the range of 0.01 to 5.0 mol% based on the monomer. Is preferred. In the synthesis of the polymer of the present invention, the monomers forming A, B and C are mixed and first put into a reaction vessel, and then an initiator may be charged, or a process of dropping these monomers into a polymerization solvent. The polymerization may be carried out via

The polymer represented by the general formula (5) of the present invention has a partial structure having a function of generating an acid by the action of heat or an acid, and a partial structure which causes a change in an absorption band of 360 to 900 nm by the action of an acid. It is a polymer having both Such a polymer may be a polymer of a single monomer having both functions, but the structure represented by the general formula (5) is generally used from a synthetic viewpoint. The image recording medium of the present invention is generally produced by coating a polymer represented by the general formula (5) on a support. When the polymer of the present invention also has a function of generating an acid by heat, the absorption region changes only by the action of heat alone, so that when used as a heat-sensitive recording material, the sensitivity and the sharpness of the image are excellent. ing. Further, since the image recording medium of the present invention does not require the use of a so-called binder, the thickness can be reduced, a sharp image can be obtained, and abrasion does not easily occur. However, when using the polymer represented by the general formula (5), if necessary, a binder may be used in combination, and specific examples thereof include those described above.

Next, a technique for forming a multilayer image forming layer will be described. When forming a multi-color image using the image forming medium of the present invention, various materials as each color forming method,
Various schemes can be used. It is necessary to divide the layers when adverse effects such as a decrease in sensitivity, a deterioration in storage stability, and fogging are caused when they are used in a mixture in the same layer. In addition, when it is desired to provide a high-sensitivity layer and a low-sensitivity layer even when the same color is formed, it is necessary to separate the layers by some means. In some cases, it is only necessary to separately coat the support on the support as a means for forming such a multilayer, but it is preferable to provide an intermediate layer between the layers.

When an intermediate layer is provided between the layers to be separated, the binder used for the intermediate layer is not particularly limited as long as it is generally colorless and can form a transparent or translucent film. , Casein, starches, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol, polyacrylamide, water-soluble binders such as ethylene-maleic anhydride copolymer, and polyvinyl butyral, triacetyl cellulose, cellulose acetate butyrate, polyesters, polycarbonates, polyvinyl Esters (such as polyvinyl acetate), polystyrene, polyvinyl chloride, acrylate and methacrylate polymers or copolymers (eg, methyl methacrylate-hydrido) Carboxymethyl methacrylate copolymer, methyl acrylate - butadiene copolymer, polymethyl methacrylate, polymethyl t- butyl methacrylate,
Any water-insoluble binder such as acrylonitrile-butadiene copolymer can be used.

Of these binders, water-insoluble binders are preferably used. The water-insoluble binder may be formed into a film from an organic solvent, or may be formed into a film in the form of an aqueous dispersion. The water dispersion referred to herein is a water-insoluble hydrophobic polymer dispersed as fine particles in a water-soluble dispersion medium. The dispersion state is such that the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partially dispersed in polymer molecules and molecular chains themselves are molecularly dispersed. Any of them may be used. Examples of these are `` Synthetic resin emulsions (Hei Okuda, edited by Hiroshi Inagaki, published by Kobunshi Kankokai (1978))
”,“ Application of synthetic latex (Takaaki Sugimura, Yasuo Kataoka,
(Edited by Soichi Suzuki and Keiji Kasahara, published by Polymer Publishing Association (1993))
And "Synthesis of Synthetic Latex (Souichi Muroi, published by Kobunshi Kankokai (1970))" and the like. The average particle size of the dispersed particles is preferably in the range of 1 to 50,000 nm, more preferably in the range of about 5 to 1000 nm. There is no particular limitation on the particle size distribution of the dispersed particles, and they may have a wide particle size distribution or a monodispersed particle size distribution.

The molecular weight of the polymer used as a binder for these intermediate layers is 1000 to 100 in terms of weight average molecular weight.
0000, preferably about 20,000 to 500,000. Further, the polymer may be used alone, or may be used by blending two or more kinds as necessary.

The intermediate layer of the present invention may be provided in two or more layers as necessary, and the amount of the binder in each layer is from 0.2 to 0.2.
5.0 g / m ^2, more preferably in the range of 0.5 to 3.0 g / m ^2.

When an image is formed by laser irradiation, it is effective to change the method of applying a sensitizing dye to laser light as a means for increasing sensitivity. That is, when laser irradiation is performed on the image recording material, the sensitivity of the recording material is improved by increasing the coating amount of the sensitizing dye in a layer far from the laser light incident side.

In the present invention, a small amount of a base may be added for the purpose of enhancing the storage stability of the image recording medium, or a compound capable of generating an acid by the action of light or heat may be added for the purpose of enhancing the sensitivity. Various additives such as a pigment, an antioxidant, and an anti-sticking agent can be added according to the requirements. Further, an overcoat layer may be provided to protect the image recording layer, or a backcoat layer may be provided on the back surface of the support. Various known techniques for heat-sensitive recording materials can be used, such as providing a single layer or a plurality of undercoat layers made of pigment or resin between the image recording layer and the support.

When a base is added, an organic base is preferable. For example, a guanidine derivative (eg, 1,3-diphenylguanidine, 1,3-dimethylguanidine, 1,3-
Dibutylguanidine, 1-benzylguanidine, 1,
1,3,3-tetramethylguanidine, etc.), aniline derivatives (eg, aniline, pt-butylaniline, N,
N′-dimethylaniline, N, N′-dibutylaniline, triphenylamine, etc.), alkylamine derivatives (eg, tributylamine, octylamine, laurylamine, benzylamine, dibenzylamine, etc.), and heterocyclic compounds (eg, N , N'-Dimethylaminopyridine, 1,8-diazabicyclo [5.4.0] -7-
Undecene, triphenylimidazole, lutidine, 2
-Picoline) is a preferred example. These bases are 1 to 10 with respect to the composition represented by A in the general formula (1).
It is preferable to add 50 mol%, particularly preferably 5 to 20 mol%.

When the image recording medium of the present invention is used as a photon mode type image recording medium, it is essential to add a compound which generates an acid by the action of light. On the other hand, when used as a heat mode image recording medium,
If the acid generator represented by A in the general formulas (1) to (4) or (5) has a function of generating an acid by the action of heat, a thermal acid generator is separately added. Although it is not necessary, a thermal acid generator may be added separately for the purpose of increasing the sensitivity. When the acid generator represented by A in the general formulas (1) to (4) or (5) does not have a function of generating an acid by the action of heat, a thermal acid generator is separately added. It is necessary to do. When a plurality of acid generators are used in combination as described above, the general formulas (1) to (4) of the present invention are used.
A plurality of acid generators contained in (4) may be used in combination. The compounds represented by the general formulas (1) to (4) of the present invention may be used in combination with a known acid generator. Examples of known acid generators include compounds described in “Organic Materials for Imaging” edited by Organic Electronics Materials Research Society, published by Bunshin Publishing Company (1997), pp. 37-91, and references cited therein. And the like. Also,
Many of the photoacid generators described herein also function as thermal acid generators.

When a pigment is added, examples include diatomaceous earth, talc, kaolin, calcined kaolin, titanium oxide, silicon oxide, magnesium carbonate, calcium carbonate, aluminum hydroxide, and urea-formalin resin.

Other additives include UV absorbers such as benzophenone type and benzotriazole type, head wear and sticking preventives comprising higher fatty acid metal salts such as zinc stearate and calcium stearate, paraffin, paraffin oxide, polyethylene, and the like. Waxes, such as polyethylene oxide and caster wax, are mentioned, and can be added as needed.

As the support used in the image recording medium of the present invention, papers such as high-quality paper, baryta paper, coated paper, cast coated paper, synthetic paper, polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2, polyethylene-2
6-naphthylenedicarboxylate, polyarylene,
Examples thereof include polymer films such as polyimide, polycarbonate, and triacetyl cellulose, glass, metal foil, and nonwoven fabric. In the case where the image recording medium of the present invention is used for a transmission type image such as an OHP film or a plate making film, a transparent support is used. For a plate making film, a support having a small coefficient of thermal expansion and good dimensional stability and having no absorption in the photosensitive region of the PS plate is selected.

In the image recording medium of the present invention, as a heating method as an image forming means, a method of contacting with a heated block or plate, a method of contacting with a heat roller or a heat drum, a halogen lamp or an infrared or infrared There are a method of irradiating an infrared lamp heater, a method of imagewise heating with a thermal head of a thermal printer, and a method of irradiating a laser beam. The image recording medium of the present invention is used for plate making materials,
In the case where a high resolution is required, a method of scanning and exposing with a laser beam is preferable. In order to form an image with less heat energy, the heat-sensitive recording material of the present invention can be heated to an appropriate temperature in advance.
In the present invention, after imagewise heating by these methods, 60
The image can be amplified by heating the entire surface at a temperature of １５０150 ° C. (preferably 60 to 120 ° C.). That is, in the polymer of the present invention, the site A is first decomposed by heating to generate an acid, and the action of the acid causes a change in absorption of B. This reaction proceeds within a very short time due to laser light irradiation, but the image can be amplified by post-heating.

When an image is formed by irradiating a laser beam, a dye that absorbs light having the wavelength of the laser beam must be present in order to convert the laser beam into heat energy. Excimer laser, argon laser, helium neon laser, semiconductor laser, glass (YAG) laser, carbon dioxide laser,
Although there is a dye laser and the like, a helium neon laser, a semiconductor laser and a glass laser are laser light sources useful in the present invention. Among them, a semiconductor laser is particularly useful because the device is small and inexpensive. The oscillation wavelength of the semiconductor laser is usually 670 to 830 nm, and a dye having absorption in the near infrared is used. As the near-infrared absorbing dye, a cyanine dye, a squarylium dye, a merocyanine dye, an oxonol dye, a phthalocyanine dye, and the like are used. Specific examples thereof include, for example, U.S. Pat. Nos. 4,973,572, 4,948,777, 4,950,640, and 4,950,639.
Nos. 4,948,776 and 4948,778, 4,942,141, 4,952,552, 5,036,040 and 4,912,083.
And the like.

When a compound that generates an acid by light is used, a laser is selected as a means for forming a latent image in accordance with the absorption characteristics of the photoacid generator. At this time, various dyes may be added for the purpose of spectral sensitization, but in that case, it is necessary to select a laser according to the absorption wavelength of the dye.
Regarding the method for synthesizing the compound of the present invention, see JP-A-11-180.
048, 11-181031,
It can be synthesized with reference to these.

[0083]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

(Example 1) On a 175 μm-thick polyethylene terephthalate film, a color-forming layer
1, intermediate layer-1, color-forming layer-2, intermediate layer-2, color-forming layer-
3. Multilayer coating and drying in the order of the protective layer to prepare a transparent thermosensitive recording film. <Preparation of Coloring Layer Coating Solution> The following compounds were dissolved in chloroform to prepare image forming coating solutions (IM-1, 2). As the polystyrene, polystyrene beads (diameter: about 3.2 mm) manufactured by Wako Pure Chemical Industries, Ltd. were used. (Preparation of Coating Solution for the Present Invention) (IM-1) LD-7 2 mmol / m ² S-1 4 mmol / m ² IR dye 0.08 mmol / m ² polystyrene 0.5 g / m ² (IM-2) LD- 15 2 mmol / m ² S-22 4 mmol / m ² IR dye 0.08 mmol / m ² polystyrene 0.5 g / m ² (IM-3) P- (11) 2 mmol / m ² IR dye 0.08 mmol / m ² ( IM-4) P- (2) 2 mmol / m ² IR dye 0.08 mmol / m ² (IM-5) P- (11) 2 mmol / m ² IR dye 0.08 mmol / m ² (IM-6) B- ^{14 0.5mmol / m 2 S-8} 2mmol / m 2 IR dye ^{0.02mmol / m 2 (IM-7} ) P- (17) 0.5mmol / m 2 IR dye 0.02mmol / m ² (IM-8 ) LD- ^{2mmol / m 2 LD-15 2mmol} / m 2 S-8 8mmol / m 2 ( Preparation of Comparative Experiment coating solution) IR Dye ^{0.10mmol / m 2 (RI-1} ) LD-7 2mmol / m 2 S-1 4 mmol / m ² B-14 0.5 mmol / m ² S-8 8 mmol / m ² IR dye 0.10 mmol / m ² polystyrene 0.5 g / m ² (RI-2) LD-15 2 mmol / m ² S-22 4 mmol / m ² B-14 0.5 mmol / m ² S-8 2 mmol / m ² IR dye 0.10 mmol / m ² polystyrene 0.5 g / m ² (RI-3) P- (11) 2 mmol / m ² P -(17) 0.5 mmol / m ² IR dye 0.10 mmol / m ²

[0085]

Embedded image

<Preparation of Intermediate Layer Coating Solution> The following materials were mixed with an isopropanol / methyl ethyl ketone mixed solvent (70
/ 30 (vol%)) (HG-
1) was obtained. The polyvinyl butyral used was Denka Butyral 3000K manufactured by Denki Kagaku Kogyo. (MC-1) Binder (polyvinyl butyral) 1.0 g / m ²

<Preparation of Protective Layer Coating Solution> The following materials were mixed with a mixed solvent of isopropanol / methyl ethyl ketone (70
/ 30 (vol%)), a matting agent and a slipping agent were added, and the mixture was dispersed with a high-speed homogenizer to obtain a protective layer coating liquid (PC-1). Polyvinyl butyral is Denka Butyral 3000K manufactured by Denki Kagaku Kogyo Co., Ltd., matting agent is Sycilia 431 (synthetic silica: average particle diameter 2.5 μm) manufactured by Fuji Silysia Chemical, and sliding agent is cellosol 5 manufactured by Chukyo Yushi.
24 (main component: carnauba wax) was used. (PC-1) Binder (poly-t-butyl methacrylate) 1.5 g / m ² Matting agent 60 mg / m ² Sliding agent 0.2 g / m ² The compositions of the eight kinds of prepared films are shown below.

[0088]

[Table 2]

<Image Processing Conditions> Spectra Diode La
bs No.SDL-2430 (wavelength range: 800 to 830 nm)
This multiplexing was performed to obtain an output of 140 mW to obtain an image writing laser. Using this laser, beam system 20
μm, the laser energy density on the sample is 3.5 mJ /
mm ² . After performing scanning exposure on the produced film under the above laser exposure conditions, the film was heated at 120 ° C. for 30 minutes.
Thermal development under heating conditions of seconds, 365nm, 420nm,
The color density at 600 nm was determined. <Results> Table 3 summarizes the obtained results.

[0090]

[Table 3]

As is clear from the table, it is found that the color forming density is improved by separating the color forming layer in the intermediate layer (the present invention 1 and comparative example 1, the present invention 2 and comparative example 2, Invention 3 and Comparative Example 3). Further, even when the number of the color forming layers is three, a high color forming density can be obtained, and the usefulness of the present invention is apparent.

[0092]

According to the present invention, the effect of increasing the color density can be obtained particularly by providing an intermediate layer.

Claims (6)

[Claims] 1. An acid generator represented by the following general formula (1) which generates an acid by the action of heat or an acid on a support, and causes an intramolecular or intermolecular reaction by the action of an acid.
A non-silver-salt image recording medium having a coloring layer containing a compound causing a change in the absorption range of 0 to 900 nm, wherein a plurality of coloring layers are present. Formula (1) W in ¹ OP ¹ Formula, W ¹ represents a residue of an acid represented by W ¹ OH, P ¹
Represents a substituent which is released by the action of heat or an acid. 2. An acid generator represented by the general formula (1):
Being a compound selected from the general formulas (2) to (4)
The image recording medium according to claim 1, wherein: General formula (2)Where R¹Is Hammett's σ_pElectron withdrawal greater than 0
Represents a functional group. R^TwoRepresents an alkyl group. R^ThreeIs heat or
It represents a group which is released by the action of an acid. W¹Is the general formula
It is synonymous with (1). General formula (3)Where R^Four, R^Five, R⁶Is a hydrogen atom, an alkyl group,
Or an aryl group;¹Is synonymous with general formula (1)
You. General formula (4) P^Two-XLC (R⁷) (R⁸) -OW¹ Where P^TwoRepresents a substituent that is released by the action of heat or an acid.
You. X is O, S, NR ⁹(R⁹Is a hydrogen atom or replaceable
Functional group), or CR^TenR¹¹(R^TenAnd R¹¹Is
Represents a hydrogen atom or a substitutable group.
May be included). L represents a linking group. R⁷You
And R⁸Represents a hydrogen atom or a substitutable group.
May be different. W¹Is the same as in general formula (1)
Righteous. 3. A partial structure having a function of generating an acid by the action of heat or an acid, and 360 to 90 by an action of an acid.
A non-silver salt image recording medium having a coloring layer containing a polymer having a partial structure that causes a change in an absorption region of 0 nm, wherein a plurality of coloring layers are present. 4. The image recording medium according to claim 3, wherein the polymer according to claim 3 is a polymer represented by the following general formula (5). Formula (5)-(A) _x- (B) _y- (C) _{z- wherein} A is obtained by polymerization of at least one vinyl monomer having a function of generating an acid by the action of heat or an acid. B represents a repeating unit obtained by polymerization of at least one type of vinyl monomer having a partial structure that causes a change in the absorption range of 360 to 900 nm by the action of an acid; Represents a repeating unit obtained by polymerization of at least one or more kinds of polymerizable vinyl monomers, and x, y
And z represent% by weight, and 1 ≦ x ≦ 99 and 1 ≦
It represents y ≦ 99, 0 ≦ z ≦ 98, and x + y + z = 100. 5. The method according to claim 1, further comprising an infrared absorbing dye.
An image forming method, wherein an image is formed on the image forming medium described above by irradiating an infrared laser. 6. The image recording medium according to claim 1, further comprising an intermediate layer between the color forming layers.