JP2008265335A - Image formation method using thermal transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a good image formation method excellent in image toughness, which provides an image of high image quality without causing abnormal transfer in high magenta density by coping with the acceleration of thermal transfer image forming speed and the raising of a thermal head temperature. <P>SOLUTION: In the image formation method, the image is formed by superposing: a thermal transfer sheet having at least one yellow thermal transfer layer, a magenta thermal transfer layer and a cyan thermal transfer layer; and a thermal transfer image receiving sheet formed by coating using water coating liquid in this dye receiving layer concerned, wherein the magenta thermal transfer layer in the thermal transfer sheet contains at least one type of polyvinylacetacetal and specific magenta dye, and the line speed at the time of forming the image is 0.05 msec/line or more to 1.25 msec/line or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming method using a thermal transfer system during high-speed printing, and more particularly to an image forming method which gives a high magenta density and is excellent in image fastness.

  Conventionally, various thermal transfer recording methods are known, and among them, the dye diffusion transfer recording method is attracting attention as a process capable of producing a color hard copy closest to the image quality of a silver salt photograph (for example, Non-Patent Document 1 and 2). In addition, it has advantages such as being dry, easy to visualize from digital data, and easy to make duplicates compared to silver salt photography.

  In this dye diffusion transfer recording system, a thermal transfer sheet containing a pigment (hereinafter also referred to as an ink sheet) and a thermal transfer image receiving sheet (hereinafter also referred to as an image receiving sheet) are superposed, and then heat is generated by an electrical signal. By heating the ink sheet with a controlled thermal head, the dye in the ink sheet is transferred to the image receiving sheet to record image information. By recording three colors of cyan, magenta, and yellow in an overlapping manner, A color image having a continuous change in color shading can be transferred and recorded.

  In recent years, there is a user merit that if the printer speed is increased, the waiting time is shortened when printing at the store, so a high-speed sublimation thermal transfer printer that can provide printing in a short time has been developed and introduced to the market one after another. Has been. With the spread of such printers, there is a demand not only for the dye diffusion transfer recording system but also for providing a print with good and robust image quality comparable to silver salt photography.

However, with the recent increase in the image forming speed of a thermal transfer printer having a thermal head, there has been a problem that a conventional thermal transfer recording material cannot provide a sufficient image density or has insufficient tone reproducibility. As one method for dealing with such problems, when a thermal transfer printer is adjusted for the purpose of improving the dye transfer amount and the thermal head temperature is increased during image formation, a thermal transfer layer on the thermal transfer sheet (hereinafter also referred to as a dye layer). And a dye receiving layer (hereinafter also referred to as a receiving layer) on the heat-sensitive transfer image-receiving sheet, and it is known that so-called abnormal transfer occurs. If a large amount of a release agent is added to the thermal transfer layer and / or the receiving layer in order to prevent this abnormal transfer, the image density is lowered and cannot be an essential solution.
In order to solve these problems, a thermal transfer sheet containing a dye having a limited melting point, a method for changing the image forming speed of magenta and cyan (for example, Patent Documents 1, 2, and 3), and a dye on a thermal transfer image receiving sheet. Although a method for introducing a special additive into the receiving layer (for example, Patent Document 4) is disclosed, it is difficult to say that the level is sufficient.

  On the other hand, with respect to the thermal transfer image-receiving sheet, in recent years, from the viewpoint of environmental protection, a method using a latex or water-soluble polymer compound, which is an aqueous dispersion of a resin, has been proposed for the receiving layer (see, for example, Patent Documents 5 and 6). It is disclosed that this type of thermal transfer image-receiving sheet has an appropriate sensitivity and gives good printing performance. However, even when such a thermal transfer image-receiving sheet is used, it has become difficult to obtain a sufficient image density as the image forming speed increases, and particularly in the formation of a magenta dye image having high visual sensitivity. Therefore, a technique for forming a sufficient image density at a high speed is strongly demanded.

JP 2003-220768 A JP 2005-119280 A JP 2006-281510 A Japanese Examined Patent Publication No. 6-65511 JP-A-8-2123 JP 2006-88691 A “New development of information recording (hard copy) and its materials”, published by Toray Research Center, Inc., 1993, p. 241-285 “Development of printer materials”, issued by CMC Co., Ltd., 1995, p. 180

  The present invention can obtain a high-quality image with high magenta density and no abnormal transfer in response to increasing the image forming speed of thermal transfer and increasing the temperature of the thermal head. Another object of the present invention is to provide a good image forming method excellent in fastness under high humidity conditions.

As a result of intensive studies, the present inventors have improved the magenta density and image quality degradation due to the increase in thermal transfer image formation speed and thermal head temperature by using a specific magenta dye and polyvinyl acetoacetal. I found what I could do. In addition, in the process, a heat transfer image receiving sheet and a heat transfer which have a dye receiving layer prepared by coating with an aqueous coating solution that is surprisingly fast in image, particularly light fastness and high humidity. In combination with an increase in the image forming speed, it has been found that a good image with high magenta density, high image quality and excellent image robustness can be realized. The present invention has been completed based on the above findings.
That is, the said subject was achieved by the following means.
(1) A thermal transfer sheet having at least one yellow thermal transfer layer, a magenta thermal transfer layer, and a cyan thermal transfer layer, respectively, on the support, and at least one dye receiving layer on the support, An image forming method in which an image is formed by superimposing a heat-sensitive transfer image-receiving sheet whose layer is formed by coating using an aqueous coating solution,
The magenta thermal transfer layer in the thermal transfer sheet contains at least one magenta dye represented by polyvinyl acetoacetal and the following general formula (M),
An image forming method, wherein a line speed during image formation is set to 0.05 msec / line or more and 1.25 msec / line or less.

（一般式（Ｍ）において、Ｄ^１〜Ｄ^５は各々独立に、水素原子、ハロゲン原子、アルキル基、アルコキシ基、アリール基、アリールオキシ基、シアノ基、アシルアミノ基、スルホニルアミノ基、ウレイド基、アルコキシカルボニルアミノ基、アルキルチオ基、アリールチオ基、アルコキシカルボニル基、カルバモイル基、スルファモイル基、スルホニル基、アシル基、またはアミノ基を表す。Ｄ^６およびＤ^７は各々独立に水素原子、アルキル基、またはアリール基を表す。Ｄ^６とＤ^７が互いに結合して環を形成していてもよく、Ｄ^３とＤ^６または／およびＤ^５とＤ^７が互いに結合して環を形成していてもよい。Ｘ、Ｙ、およびＺは＝Ｃ（Ｄ^８）−または窒素原子を表す。ここで、Ｄ^８は水素原子、アルキル基、アリール基、アルコキシ基、アリールオキシ基、またはアミノ基を表す。また、ＸとＹが＝Ｃ（Ｄ^８）−のとき、またはＹとＺが＝Ｃ（Ｄ^８）−のとき、２つのＤ^８は互いに結合して飽和ないし不飽和炭素環を形成してもよい。これらの各基はさらに置換基を有していてもよい。）
（２）前記感熱転写受像シートが、受容層と支持体の間に中空ポリマーと親水性ポリマーを含有する少なくとも１層の断熱層を有することを特徴とする（１）に記載の画像形成方法。
（３）前記感熱転写受像シートにおいて、断熱層に含まれる親水性ポリマーの少なくとも１種がゼラチンであることを特徴とする（１）または（２）に記載の画像形成方法。
（４）前記感熱転写受像シートが、水系同時重層塗布により製造されてなることを特徴とする（１）〜（３）のいずれか１項に記載の画像形成方法。
（５）前記画像形成時において、画像形成時のプリンタのサーマルヘッドの最高到達温度Ｔｍを１８０℃以上４５０℃以下とすることを特徴とする（１）〜（４）のいずれか１項に記載の画像形成方法。
（６）前記画像形成時のライン速度を０．０５ｍ秒／ｌｉｎｅ以上０．８秒／ｌｉｎｅ以下とすることを特徴とする（１）〜（５）のいずれか１項に記載の画像形成方法。
（７）前記感熱転写シート中のマゼンタ熱転写層に含まれるマゼンタ染料が下記一般式（ＭＢ）で表される化合物であることを特徴とする（１）〜（６）のいずれか１項に記載の画像形成方法。

(In General Formula (M), D ^{1 to} D ⁵ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, an acylamino group, a sulfonylamino group, a ureido group, An alkoxycarbonylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, or an amino group, each of D ⁶ and D ⁷ independently represents a hydrogen atom, an alkyl group, or an aryl group; D ⁶ and D ⁷ may be bonded to each other to form a ring, or D ³ and D ⁶ or / and D ⁵ and D ⁷ may be bonded to each other to form a ring. X, Y, and Z = C ^{(D 8)} -. represents a or a nitrogen atom wherein, ^{D 8} is hydrogen atom, an alkyl group, an aryl group, alkoxycarbonyl . Shi represents a group, an aryloxy group or an amino group, Further, X and Y are = C ^{(D 8)} - when, or Y and Z are = C ^{(D 8)} - when, two ^{D 8} together They may combine to form saturated or unsaturated carbocycles, each of which may further have a substituent.)
(2) The image forming method according to (1), wherein the heat-sensitive transfer image-receiving sheet has at least one heat insulating layer containing a hollow polymer and a hydrophilic polymer between the receiving layer and the support.
(3) The image forming method according to (1) or (2), wherein in the heat-sensitive transfer image-receiving sheet, at least one hydrophilic polymer contained in the heat insulating layer is gelatin.
(4) The image forming method according to any one of (1) to (3), wherein the heat-sensitive transfer image-receiving sheet is produced by aqueous simultaneous multilayer coating.
(5) In any one of (1) to (4), the maximum temperature Tm of the thermal head of the printer during the image formation is set to 180 ° C. or higher and 450 ° C. or lower. Image forming method.
(6) The image forming method according to any one of (1) to (5), wherein a line speed at the time of image formation is set to 0.05 msec / line or more and 0.8 second / line or less. .
(7) The magenta dye contained in the magenta thermal transfer layer in the thermal transfer sheet is a compound represented by the following general formula (MB), (1) to (6), Image forming method.

（一般式（ＭＢ）において、Ｄ^１９〜Ｄ^２３は各々独立に、水素原子、ハロゲン原子、アルキル基、アルコキシ基、アリール基、アリールオキシ基、シアノ基、アシルアミノ基、スルホニルアミノ基、ウレイド基、アルコキシカルボニルアミノ基、アルキルチオ基、アリールチオ基、アルコキシカルボニル基、カルバモイル基、スルファモイル基、スルホニル基、アシル基、またはアミノ基を表す。Ｄ^２４およびＤ^２５は各々独立に水素原子、アルキル基またはアリール基を表す。Ｄ^２４とＤ^２５が互いに結合して環を形成していてもよく、Ｄ^２１とＤ^２４または／およびＤ^２３とＤ^２５が互いに結合して環を形成していてもよい。Ｄ^２６は水素原子、アルキル基、アリール基、アルコキシ基、アリールオキシ基、またはアミノ基を表す。これらの各基はさらに置換基を有してもよい。）
（８）前記感熱転写シートシートにおいて、イエロー熱転写層、マゼンタ熱転写層、シアン熱転写層が支持体上に面順次に形成されていることを特徴とする（１）〜（７）のいずれか１項に記載の画像形成方法。
（９）前記感熱転写シートシートが、さらに熱転写可能な保護層を有することを特徴とする（１）〜（８）のいずれか１項に記載の画像形成方法。

(In the general formula (MB), D ^{19 to} D ²³ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, an acylamino group, a sulfonylamino group, a ureido group, An alkoxycarbonylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, or an amino group, and D ²⁴ and D ²⁵ each independently represent a hydrogen atom, an alkyl group, or an aryl group; D ²⁴ and D ²⁵ may be bonded to each other to form a ring, or D ²¹ and D ²⁴ or / and D ²³ and D ²⁵ may be bonded to each other to form a ring. ²⁶ is a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group or an amino group, You. May have each of these groups are further substituted.)
(8) Any one of (1) to (7), wherein in the thermal transfer sheet, the yellow thermal transfer layer, the magenta thermal transfer layer, and the cyan thermal transfer layer are formed in a surface sequence on the support. The image forming method described in 1.
(9) The image forming method according to any one of (1) to (8), wherein the thermal transfer sheet sheet further has a protective layer capable of thermal transfer.

  According to the image forming method of the present invention, a sharp and smooth photographic image such as a silver salt photograph can be realized in a dry condition that does not require a developer and has excellent processability, and further, “high speed image formation by thermal transfer”. ”And“ Higher thermal transfer temperature of the thermal head ”, high magenta density in the transferred image, high image quality, and long-term image robustness that does not cause image degradation, especially light There is an excellent effect that a good image excellent in fastness and fastness under high-humidity conditions can be formed.

Hereinafter, the present invention will be described in detail.
In the image forming method of the present invention, a thermal transfer sheet having at least one yellow thermal transfer layer, a magenta thermal transfer layer, and a cyan thermal transfer layer on a support, and a sensitivity having at least one dye-receiving layer on the support. An image is formed by superimposing the image on a thermal transfer image receiving sheet. In the present invention, the magenta thermal transfer layer contains a magenta dye having a specific structure and polyvinyl acetoacetal. Further, the line speed at the time of image formation is set to 0.05 msec / line or more and 1.25 msec / line or less.

  The magenta thermal transfer layer (magenta dye layer) of the thermal transfer sheet used in the image forming method of the present invention must contain at least one compound represented by the above general formula (M) as a magenta dye.

In the general formula (M), D ^{1 to} D ⁵ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, an acylamino group, a sulfonylamino group, a ureido group, an alkoxy group. A carbonylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, or an amino group is represented. D ⁶ and D ⁷ each independently represent a hydrogen atom, an alkyl group, or an aryl group. D ⁶ and D ⁷ may be bonded to each other to form a ring, or D ³ and D ⁶ or / and D ⁵ and D ⁷ may be bonded to each other to form a ring. X, Y, and Z represent ═C (D ⁸ ) — or a nitrogen atom. Here, D ⁸ represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, or an amino group. When X and Y are = C (D ⁸ )-, or Y and Z are = C (D ⁸ )-, the two D ⁸ are bonded to each other to form a saturated or unsaturated carbocycle. Also good. Each of these groups may further have a substituent.

D ^{1 to} D ⁵ are each independently a hydrogen atom, a halogen atom (eg, chlorine atom, bromine atom, fluorine atom, etc.), an alkyl group (preferably having 1 to 12 carbon atoms, eg, methyl, ethyl, isopropyl, n- Propyl, t-butyl, etc.), alkoxy groups (preferably having 1 to 12 carbon atoms, such as methoxy, butoxy, octyloxy, dodecyloxy, etc.), aryl groups (preferably having 6 to 10 carbon atoms, such as phenyl, m-nitro, etc. Phenyl, p-nitrophenyl, p-tolyl, naphthyl, etc.), aryloxy groups (preferably having 6 to 10 carbon atoms, such as phenyloxy, m-nitrophenyloxy, p-nitrophenyloxy, p-tolyloxy, naphthyloxy, etc.) ), A cyano group, an acylamino group (preferably having 1 to 12 carbon atoms, such as formylamino, Cetylamino, butylcarbonylamino, octylcarbonylamino, etc.), sulfonylamino groups (preferably having 1 to 12 carbon atoms, such as methanesulfonamide, butanesulfonamide, octanesulfonamide, benzenesulfonamide, toluenesulfonamide), ureido group (Preferably having 1 to 12 carbon atoms, such as N-methylureido, N, N-dimethylureido, N-phenylureido, N-methyl-N-phenylureido, N-octylureido, etc.), alkoxycarbonylamino group (preferably 2 to 12 carbon atoms, such as methoxycarbonylamino, ethoxycarbonylamino, isopropoxycarbonylamino, n-octyloxycarbonylamino, etc.)

An alkylthio group (preferably having 1 to 12 carbon atoms, such as methylthio, ethylthio, butylthio, octylthio, isobutylthio t-octylthio, etc.), an arylthio group (preferably having 6 to 10 carbon atoms, such as phenylthio, naphthylthio, etc.), alkoxycarbonyl A group (preferably having 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, isopropoxycarbonyl, n-octyloxycarbonyl, etc.), a carbamoyl group (preferably having 1 to 12 carbon atoms, such as N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-phenylcarbamoyl, N-butyl-N-phenylcarbamoyl, etc.), sulfamoyl group (preferably having 1 to 12 carbon atoms, such as N-methylsulfamoyl, N-phenylsulfamoyl, N- Til-N-phenylsulfamoyl and the like), sulfonyl groups (preferably having 1 to 12 carbon atoms, such as methylsulfonyl, butylsulfonyl, benzenesulfonyl, toluenesulfonyl and the like), acyl groups (preferably having 1 to 12 carbon atoms, such as , Formyl, acetyl, lauroyl, etc.) or an amino group (preferably having 0 to 12 carbon atoms, such as amino, methylamino, phenylamino, N-methylN-phenylamino, octylamino, etc.), D ⁶ and D ⁷ Each independently represents a hydrogen atom, an alkyl group (preferably having 1 to 12 carbon atoms, such as methyl, ethyl, isopropyl, n-propyl, t-butyl, etc.), an alkoxy group (preferably having 1 to 12 carbon atoms, such as methoxy , Butoxy, octyloxy, dodecyloxy, etc.) or aryl groups (preferably Preferably, it represents 6 to 10 carbon atoms, such as phenyl, m-nitrophenyl, p-nitrophenyl, p-tolyl, naphthyl and the like. D ⁶ and D ⁷ may be bonded to each other to form a ring, or D ³ and D ⁶ or / and D ⁴ and D ⁷ may be bonded to each other to form a ring.

X, Y, and Z represent ═C (D ⁸ ) — or a nitrogen atom. Here, D ⁸ is a hydrogen atom, an alkyl group (preferably having 1 to 12 carbon atoms, such as methyl, ethyl, isopropyl, n-propyl, t-butyl, etc.), an aryl group (preferably having 6 to 10 carbon atoms, such as, for example, Phenyl, m-nitrophenyl, p-nitrophenyl, p-tolyl, naphthyl, etc.), alkoxy groups (preferably having 1 to 12 carbon atoms, such as methoxy, butoxy, octyloxy, dodecyloxy, etc.), aryloxy groups (preferably Has 6 to 10 carbon atoms such as phenyloxy, m-nitrophenyloxy, p-nitrophenyloxy, p-tolyloxy, naphthyloxy, etc.) or an amino group (preferably having 0 to 12 carbon atoms such as amino, methylamino, Phenylamino, N-methyl N-phenylamino, octylamino and the like). When X and Y are = C (D ⁸ )-, or Y and Z are = C (D ⁸ )-, the two D ⁸ are bonded to each other to form a saturated or unsaturated carbocycle. Also good. Each of the above groups may further have a substituent. Examples of the substituent include a halogen atom, alkyl group, alkoxy group, aryl group, aryloxy group, cyano group, acylamino group, sulfonylamino group, ureido group, alkoxycarbonylamino group, alkylthio group, arylthio group, alkoxycarbonyl group, Examples thereof include a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, a heterocyclic group, a sulfo group, a carboxyl group, a hydroxyl group, and an amino group.

D ¹ is preferably an alkyl group (preferably having 1 to 12 carbon atoms, e.g., methyl, ethyl, isopropyl, n- propyl, t- butyl etc.), aryl group (preferably having 6 to 10 carbon atoms, such as phenyl, m -Nitrophenyl, p-nitrophenyl, p-tolyl, naphthyl, m-chlorophenyl, p-chlorophenyl, etc.). More preferably, it is an aryl group (preferably having 6 to 10 carbon atoms, such as phenyl, m-nitrophenyl, p-nitrophenyl, p-tolyl, naphthyl, m-chlorophenyl, p-chlorophenyl, etc.).

D ^{2 to} D ⁵ are preferably a hydrogen atom or an alkyl group (preferably having a carbon number of 1 to 12, such as methyl, ethyl, isopropyl, n-propyl, t-butyl, etc.), preferably a hydrogen atom or carbon These are alkyl groups having 1 to 3 and may further have a substituent.

Preferred for D ⁶ is an unsubstituted or substituted alkyl group having 3 to 6 carbon atoms, an alkyl group, an alkoxy group, a nitro group or a cyano group, more preferably an unsubstituted or substituted group having 3 to 6 carbon atoms. , An alkyl group substituted with a cyano group.

D ^7, it is also preferred example is a structure represented by the following general formula (II) or (III).

In the formula, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, a halogen atom, an alkoxy group, an aryloxy group, an amino group, an acyl group, or an acyloxy group. Represents an acylamino group, an alkylthio group, an arylthio group, a sulfonylamino group, a sulfonyl group, a sulfinyl group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group or an aryloxycarbonyl group. Preferably, it is a hydrogen atom or an alkyl group (preferably having 1 to 12 carbon atoms, such as methyl, ethyl, isopropyl, n-propyl, t-butyl, etc.), more preferably a hydrogen atom, a methyl group or an ethyl group. . R ⁷ is a hydrogen atom, alkyl group, aryl group, heterocyclic group, halogen atom, alkoxy group, aryloxy group, amino group, acyl group, acyloxy group, acylamino group, alkylthio group, arylthio group, sulfonylamino group, sulfonyl Represents a group, a sulfinyl group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group or an aryloxycarbonyl group. Preferably, it is an aryl group (preferably having 6 to 10 carbon atoms, such as phenyl, m-nitrophenyl, p-nitrophenyl, p-tolyl, p-methoxyphenyl, naphthyl, m-chlorophenyl, p-chlorophenyl, etc.). n represents 1 to 5, preferably 1 to 3. When n is 2 or more, the plurality of R ⁸ , R ⁹ , R ¹⁰ , and R ¹¹ may be the same as or different from each other.

  Of the compounds represented by the general formula (M), the compound represented by the general formula (MB) is more preferable.

In the general formula (MB), D ^{19 to} D ²³ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, an acylamino group, a sulfonylamino group, a ureido group, an alkoxy group. A carbonylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, or an amino group is represented. D ²⁴ and D ²⁵ each independently represent a hydrogen atom, an alkyl group or an aryl group. D ²⁴ and D ²⁵ may be bonded to each other to form a ring, or D ²¹ and D ²⁴ or / and D ²² and D ²⁵ may be bonded to each other to form a ring. D ²⁶ represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, or an amino group. Each of these groups may further have a substituent.

  Below, the specific example of the pigment | dye represented by general formula (M) is shown. The present invention is not limited thereby.

  These compounds can be easily synthesized by the method described in JP-A-5-286268 or a method analogous thereto.

  The magenta thermal transfer layer (magenta dye layer) of the thermal transfer sheet used in the image forming method of the present invention contains at least one compound represented by the above general formula (M) as a magenta dye. The magenta dye may be contained. For example, a dye that has been used as a dye for a heat-sensitive transfer sheet is not particularly limited as long as it can be incorporated into a heat-sensitive transfer sheet that is diffused by heat, and can be transferred from a heat-sensitive transfer sheet to an image-receiving sheet by heating, Alternatively, known dyes can be used in combination. Among these, the dye represented by the following general formula (M2) can be preferably used. However, in the present invention, the magenta dye that can be used in combination with the magenta dye represented by the general formula (M) is not limited thereto.

In general formula (M2), ring D represents a substituted or unsubstituted benzene ring, and R ⁹ , R ¹⁰ and R ¹¹ are each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted group Alternatively, it represents an unsubstituted aryl group. R ⁹ further represents a hydrogen atom.

Each group of R ⁹ , R ¹⁰ and R ¹¹ may further have a substituent. Examples of the substituent that each group of ring D, R ⁹ , R ¹⁰ and R ¹¹ may be substituted include a substituent of R ^{14 in} the general formula (C1) described later, a hydroxyl group, and a nitro group.

A preferable combination of substituents of the dye represented by the general formula (M2) is a benzene ring in which the ring D is substituted with an acylamino group having 2 to 8 carbon atoms, and R ⁹ is a substituted or unsubstituted carbon atom having 1 to 2 carbon atoms. 8 is an alkyl group or an acyl group, R ¹⁰ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms or an allyl group, and R ¹¹ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms or allyl. A combination that is a group.
A more preferable combination of substituents is a benzene ring in which ring D is substituted with an acylamino group having 2 to 6 carbon atoms, R ⁹ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or an acyl group, R ¹⁰ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms and an allyl group, and R ¹¹ is a combination of a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms and an allyl group.

A particularly preferred combination of substituents is a benzene ring in which Ring D is substituted with an acylamino group having 2 to 4 carbon atoms, R ⁹ is a substituted or unsubstituted alkyl group with 1 to 4 carbon atoms, or an acyl group, R ¹⁰ is a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms and an allyl group, and R ¹¹ is a combination of a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms and an allyl group.

Next, the yellow dye preferably used in the present invention will be described.
As yellow dyes preferably used in the present invention, in addition to existing dyes such as Disperse Yellow 231, Disperse Yellow 201 and Solvent Yellow 93, the following dyes are also preferably used.

一般式（Ｙ２）中、Ｂ^１は置換もしくは無置換のアリール基、または置換もしくは無置換の芳香族複素環基を表し、Ｒ^３は置換もしくは無置換のアルキル基を表し、Ｒ^４は置換もしくは無置換のアルキル基、または置換もしくは無置換のアリール基を表す。

In General Formula (Y2), B ¹ represents a substituted or unsubstituted aryl group, or a substituted or unsubstituted aromatic heterocyclic group, R ³ represents a substituted or unsubstituted alkyl group, and R ⁴ represents a substituted or unsubstituted alkyl group. It represents an unsubstituted alkyl group or a substituted or unsubstituted aryl group.

Each group of R ³ and R ⁴ may further have a substituent. Examples of the substituent that each group of B ¹ , R ^3, and R ⁴ may be substituted include a substituent of R ^{14 in} the general formula (C1) described later, a hydroxyl group, and a nitro group.
The aryl group for B ¹ is preferably a phenyl group which may have a substituent.

A preferable combination of substituents of the dye represented by the general formula (Y2) is a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted pyrazolyl group, a substituted or unsubstituted thiadiazolyl group represented by B ¹ R ³ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, R ⁴ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted carbon group having 6 to 10 carbon atoms. A combination that is an aryl group.
More preferable substituent combinations of the substituents are as follows: B ¹ is a substituted or unsubstituted phenyl group, a substituted or unsubstituted 1,3,4-thiadiazolyl group, and R ³ is a substituted or unsubstituted carbon group having 1 to ³ carbon atoms. 6 is a combination in which R ⁴ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms and a substituted or unsubstituted phenyl group.
The most preferred combination of substituents of substituents is a 1,3,4-thiadiazolyl group in which B ¹ is a 4-nitrophenyl group and a thioalkyl group having 1 to 6 carbon atoms, and R ³ is an unsubstituted carbon number. A combination of 1 to 4 alkyl groups, wherein R ⁴ is an unsubstituted alkyl group having 1 to 4 carbon atoms and a substituted or unsubstituted phenyl group. Preferable substituents for the phenyl group of R ⁴ are 2-chloro group, 4-chloro group, 2,4,6-trichloro group, 4-carboxymethyl group, and 4-carboxyethyl group.

  Specific examples of the dye represented by formula (Y2) used in the present invention are shown below. The present invention is not limited thereby.

  These dyes can be easily synthesized by the method described in JP-A 1-222592 or a method analogous thereto.

Next, a cyan dye that is preferably used in the present invention will be described.
In the thermal transfer layer of the ink sheet used in the present invention, a known dye that has been conventionally used can be used as a cyan dye. It is preferable to use a dye. However, the cyan dye used in the present invention is not limited to these dyes.

  The dye represented by formula (C1) will be described.

In general formula (C1), R ¹² and R ¹³ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. R ¹⁴ represents a hydrogen atom or a substituent.

Each group of R ¹² and R ¹³ may further have a substituent. Examples of the substituent that each group of R ¹² and R ¹³ may be substituted include a substituent of R ¹⁴ described later, a hydroxyl group, and a nitro group. As the substituent in R ¹⁴ in addition to the preferred substituents described below, a hydroxyl group, a nitro group.

The substituent for R ¹⁴ is preferably a halogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, cyano group, alkoxy group, aryloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group , Aryloxycarbonyloxy group, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl or arylsulfonylamino group, alkylthio group, sulfamoyl group, alkyl or Arylsulfinyl group, alkyl or arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group (each of these groups further has a substituent) More preferably a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryl. Oxycarbonyloxy group, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkylthio group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, more preferably , A halogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 8 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, substituted or unsubstituted A heterocyclic group of Job aryloxycarbonyl group, an aryloxycarbonyl group, more preferably a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, an alkoxy moiety is an alkoxycarbonyl group having 1 to 4 carbon atoms.

In the preferred combination of substituents of the dye represented by the general formula (C1), R ¹² is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms. , R ¹³ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms.
A more preferable combination of substituents is that R ¹² is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted phenyl group, and R ¹³ is substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. A combination that is a group, a substituted or unsubstituted phenyl group.
The most preferred combination of substituents is that R ¹² is a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, R ¹³ is a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, substituted or unsubstituted phenyl A combination that is a group.

  Among the dyes represented by the general formula (C1), those not commercially available are disclosed in U.S. Pat. Nos. 4,757,046, 3,770,370, German Patent No. 2316755, and JP-A No. 2316755. 2004-51873, JP-A-7-137455, JP-A-61-31292, and J.P. Chem. Soc. Perkin transfer I, 2047 (1977), by Champan, “Merocyanine Dye-Doner Element Used in Thermal Dye Transfer”.

  Next, the dye represented by formula (C2) will be described in detail.

In general formula (C2), ring E represents a substituted or unsubstituted benzene ring, R ¹⁵ represents a hydrogen atom or a halogen atom, R ¹⁶ represents a substituted or unsubstituted alkyl group, and R ¹⁷ represents substituted or unsubstituted. R ¹⁸ and R ¹⁹ each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl, and represents a substituted acylamino group or a substituted or unsubstituted alkoxycarbonylamino group. Represents a group.

Each group of ring E, R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ may further have a substituent. Examples of the substituent that each group of ring E, R ¹⁶ , R ¹⁷ , R ^18, and R ¹⁹ may be substituted include a substituent of R ^{14 in} formula (C1), a hydroxyl group, and a nitro group.

Preferred combinations of substituents of the dye represented by the general formula (C2) are a benzene ring substituted with an alkyl group having 1 to 4 carbon atoms, a benzene ring substituted with a chlorine atom, and an unsubstituted benzene ring. R ¹⁵ is a hydrogen atom, a chlorine atom or a bromine atom, R ¹⁶ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, and R ¹⁷ is a substituted or unsubstituted acylamino group having 2 to 10 carbon atoms. A substituted or unsubstituted alkoxycarbonylamino group having 2 to 10 carbon atoms, R ¹⁸ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, and R ¹⁹ is a substituted or unsubstituted carbon atom having 1 to 8 carbon atoms. A combination of 8 alkyl groups.
A more preferable combination of substituents is that the ring E is a benzene ring or an unsubstituted benzene ring substituted with an alkyl group having 1 to 2 carbon atoms, R ¹⁵ is a hydrogen atom or a chlorine atom, and R ¹⁶ is substituted or unsubstituted. an alkyl group having 1 to 6 carbon atoms substituted, R ¹⁷ is a substituted or unsubstituted acylamino group having 2 to 8 carbon atoms or a substituted or unsubstituted alkoxycarbonylamino group having 2 to 8 carbon atoms, R ¹⁸ Is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R ¹⁹ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.
The most preferable combination is a combination of preferred substituents. Ring E is a benzene ring substituted with a methyl group or an unsubstituted benzene ring, R ¹⁵ is a hydrogen atom or a chlorine atom, and R ¹⁶ is a substituted or unsubstituted carbon. An alkyl group having 1 to 6 carbon atoms, R ¹⁷ is a substituted or unsubstituted acylamino group having 2 to 6 carbon atoms, a substituted or unsubstituted alkoxycarbonylamino group having 2 to 6 carbon atoms, and R ¹⁸ is substituted or unsubstituted The combination is an unsubstituted alkyl group having 1 to 4 carbon atoms, and R ¹⁹ is a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms.

  The thermal transfer layer of each color of the thermal transfer sheet used in the present invention contains a binder resin in addition to the dye.

  Here, various binder resins are known, and these can be used in the present invention. Examples include modified cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and cellulose nitrate, polyvinyl alcohol, polyvinyl acetate , Polyvinyl resins such as polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, polystyrene, polyvinyl chloride, acrylic resins such as polyacrylonitrile, polyacrylate, polyacrylamide, polyurethane resins, polyamide resins, polyester resins, polycarbonate resins, phenoxy resins , Phenol resin, epoxy resin, various elastomers, etc. It is possible to have. In addition to using these alone, it is also possible to use them by mixing or in the case of polymers, copolymerizing each constituent monomer. Crosslinking with various crosslinking agents is also a preferred embodiment. Among these, modified cellulose resins and vinyl resins are preferably used, and propionic acid modified celluloses, polyvinyl butyral, and polyvinyl acetal can be more preferably used.

  The magenta thermal transfer layer (magenta dye layer) used in the present invention contains at least one polyvinyl acetoacetal as a binder resin. The polyvinyl acetoacetal resin is obtained by acetalizing polyvinyl alcohol, and those represented by the following general formula A are preferred.

In the formula, R represents a hydrogen atom or an alkyl group, and l + m + n = 100 mol%. When R is H, vinyl formal resin, R is CH ₃ and polyvinyl acetoacetal resin, and R is C ₃ H ₇ is polyvinyl butyral resin.

When acetalizing polyvinyl alcohol (PVA), as shown in the general formula A, it is difficult to acetalize all hydroxyl groups, and acetyl groups and hydroxyl groups inevitably remain partially. The polyvinyl acetoacetal resin as a binder component has a mass% of the acetal part of 50% or more, preferably 60% or more, more preferably 70% or more, based on the total amount of the polymer, 70% by mass or more of the acetal part, Preferably 85 mass% or more is polyvinyl acetoacetal (70 mass% or more of R in the general formula A, preferably 85 mass% or more is CH ₃ ). Moreover, as a preferable number average molecular weight, it is 20000-200000.

  A dye ink is prepared by dissolving or dispersing the sublimable dye and the binder resin in a solvent, and various known solvents can be used as the solvent used in this case. Examples include alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol and isobutanol. Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Aromatic solvents such as toluene and xylene, and water are listed. These solvents may be used alone or in combination.

  In addition to dyes and binders, various additives can be added to the thermal transfer layer for the purpose of improving various performances such as storage stability, runnability in the printer, and releasability after printing. As typical additives, organic or inorganic fine particles and waxes are preferably used.

  Examples of organic fine particles include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as fluororesins and nylon resins, urethane resins, styrene / acrylic cross-linked resins, phenol resins, urea resins, melamine resins, polyimide resins, benzoguanamine resins, and the like. These fine particles can be suitably used, and polyethylene fine particles are more preferably used. Moreover, as inorganic fine particles, fine particles such as calcium carbonate, silica, clay, talc, titanium oxide, magnesium hydroxide, and zinc oxide can be preferably used.

  The organic or inorganic fine particles are preferably contained in the range of 0.5 to 5% by mass with respect to the binder resin of the thermal transfer layer ink.

  In addition to the sublimation dye, binder resin, and organic or inorganic fine particles described above, it is also a preferred embodiment that the thermal transfer layer ink contains a wax. The wax used is a petroleum-derived wax such as microcrystalline wax or paraffin wax. Mineral-derived wax such as montan wax. Plant-derived waxes such as carnauba wax, wood wax, and candelilla wax. Animal-derived waxes such as beeswax, whale wax, ibota wax, shellac wax. Synthetic waxes such as Fischer-Tropsch wax, various low molecular weight polyethylenes, fatty acid esters, fatty acid amides, silicone waxes, and partially modified waxes are preferably used.

  Another preferred embodiment includes the inclusion of resins such as silicone resin, fluororesin, acrylic resin, cellulose resin, vinyl chloride-vinyl acetate copolymer, and nitrified cotton. Such waxes and resins may be contained in the range of 0.1 to 10% by mass, preferably in the range of 1 to 3% by mass, based on the total solid content of the thermal transfer layer ink formed as a thermal transfer layer. it can.

Next, the configuration of the thermal transfer sheet of the present invention will be described.
The thermal transfer sheet of the present invention is a thermal transfer sheet in which at least one color or more of a thermal transfer layer (hereinafter also referred to as “dye layer”) is provided on one surface of a support, and the thermal transfer layer is the above-described thermal transfer layer. It is preferably formed by applying a thermal transfer layer ink.

  Any conventionally known support can be used as long as it has the required heat resistance and strength. Examples include thin papers such as glassine paper, condenser paper, puffin paper, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polyether sulfone, and other high heat resistant polyesters, polypropylene, polycarbonate, Specific examples of preferred supports are cellulose acetate, polyethylene derivatives, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polymethylpentene, ionomer and other plastic stretched or unstretched films, and laminates of these materials As mentioned. Polyester films are particularly preferred among these. The thickness of the support is appropriately selected according to the material so that the strength, heat resistance and the like are appropriate, but a thickness of about 1 to 100 μm is preferably used. More preferably, it is about 2-50 micrometers, More preferably, about 3-10 micrometers is used.

In the sublimation type thermal transfer recording method, it is necessary to transfer only the dyes of each hue contained in the thermal transfer sheet at the time of printing, and transfer of the resin carrying the dye is not preferable. For this purpose, the adhesion between the thermal transfer layer of the thermal transfer sheet and the support must be strong. If this adhesion is weak, the thermal transfer layer itself adheres to the thermal transfer image-receiving sheet and the image quality of the print is impaired.
However, in the case of the polyester film described above as an example of a suitable support, it cannot be said that the wettability of the ink of each hue described later is good, and the adhesive force may be insufficient.
In order to cope with this, a method of treating the surface of the support by a physical means and / or a method of forming an easy adhesion layer is preferably used.

It is preferable that an easy-adhesion layer made of a resin is formed on a support and a thermal transfer layer is provided thereon. In order to form an easy-adhesion layer, urethane resin, polyester resin, polypropylene resin, polyol resin, acrylic resin, and a reaction product of these resins with isocyanates can be used. Examples of isocyanates include conventionally used diisocyanate compounds and triisocyanate compounds. The coating amount is preferably 0.05 to 0.1 g / m ² .
In producing the heat-sensitive transfer sheet, it is possible to use a support provided with an easy-adhesion layer in advance and form a heat transfer layer thereon.

The thermal transfer layer (dye layer) is formed by applying a thermal transfer layer ink on a support by a gravure printing method or other forming means and drying it. The thermal transfer layer ink is obtained by dissolving or dispersing a sublimable dye, a binder resin, and other additives such as organic or inorganic fine particles and wax, if necessary, in an appropriate solvent.
The thickness of the thermal transfer layer is preferably about 0.2 to 5 g / m ² in a dry state, and more preferably about 0.4 to ² g / m ² . The sublimation dye content in the thermal transfer layer is preferably 5 to 90% by mass, more preferably about 10 to 70% by mass.

  In the image forming method of the present invention, a thermal transfer sheet as a preferred embodiment thereof includes only a yellow thermal transfer layer, a magenta thermal transfer layer, a cyan thermal transfer layer, and a thermal transferable protective layer arranged in the order of the plane (FIG. 1, see FIG. However, as another embodiment, a black layer may be provided as the dye ink layer 3 (see FIG. 3). Since the peelability between the heat-sensitive transfer sheet and the heat-sensitive transfer image-receiving sheet, which will be described later, may change depending on the order of the above layers, it is also a preferable aspect to change the content of the additive depending on each heat-transfer layer. For example, the content of the release agent can be increased as the thermal transfer layer is printed later. In the present invention, instead of providing each hue layer on the same support, it is also possible to form a thermal transfer layer of each hue on a separate support.

In the image forming method of the present invention, in the thermal transfer sheet, the thermal transfer layer may have a single layer structure, or may have a two-layer structure or a multilayer structure of three or more layers. Moreover, in the thermal transfer layer of each hue, a single layer structure and a multilayer structure may be mixed. In the embodiment shown in FIG. 2, the yellow thermal transfer layer Y, the magenta thermal transfer layer M, and the cyan thermal transfer layer C have a single layer structure.
Thermal transfer layer total thickness of the multilayer structure is preferably about 0.2-5 g / ^{m 2,} about 0.4~2g / ^{m 2} is more preferred. The thickness of one layer constituting the thermal transfer layer is preferably about 0.2 to ² g / m ² . The sublimable dye contained in the entire thermal transfer layer is about 5 to 90% by mass, preferably about 10 to 70% by mass.

  In the image forming method of the present invention, it is preferable to provide a thermal transfer sheet with a laminate of a heat transferable protective layer. The thermal transferable protective layer (laminate) 4 is for forming a protective layer made of a transparent resin on the thermally transferred image by thermal transfer to cover and protect the image, and is resistant to scratches, light resistance and weather resistance. It is used to improve durability. If the dye transferred on the image receiving sheet is exposed to the surface, the image durability such as light resistance, scratch resistance, chemical resistance, etc. may be insufficient, and such a transparent protective layer should be provided. Is preferred. In the embodiment shown in FIG. 2, the release layer 4a, the protective layer 4b, and the adhesive layer 4c are arranged in this order on the support 2 from the support side. It is also possible to form the protective layer with a plurality of layers. When the protective layer has the functions of other layers, the release layer and the adhesive layer can be omitted. As the support, a support provided with an easy-adhesion layer can also be used.

  As the resin for forming the protective layer, a resin excellent in scratch resistance, chemical resistance, transparency and hardness is preferable. Polyester resin, polystyrene resin, acrylic resin, polyurethane resin, acrylic urethane resin, silicone modification of each of these resins Examples thereof include resins, mixtures of these resins, ionizing radiation curable resins, ultraviolet blocking resins, and the like. In addition, various resins conventionally known as protective layer forming resins can be used. In addition, UV absorbers, antioxidants, fluorescent brighteners, organic fillers, and / or inorganic fillers may be added as necessary for the purpose of imparting UV absorption, film breakage during transfer, gloss, whiteness improvement, etc. It is also preferable to add appropriately.

  The acrylic resin is preferably a polymer composed of at least one monomer selected from acrylate monomers and methacrylate monomers, and styrene, acrylonitrile, etc. may be copolymerized in addition to the acrylic monomers. A preferable monomer is methyl methacrylate, and the content is preferably 50% by mass or more in terms of the charged mass ratio.

  As the polyester resin, a saturated polyester resin can be used. As an acid component of the polyester resin, for example, aromatics include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid tetrahydrophthalic acid, hexa Examples include hydrophthalic acid, hexahydroisophthalic acid, and hexahydroterephthalic acid. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer acid. Examples of the alicyclic dicarboxylic acid include cyclohexane dicarboxylic acid, tricyclodecane dicarboxylic acid, decalin dicarboxylic acid, and the like. These compounds may be methyl esterified or may be acid anhydrides thereof. .

  Furthermore, p- (hydroxyethoxy) benzoic acid, hydroxypivalic acid, γ-butyryllactone, ε-caprolactone, fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid and the like can be used in combination. . Further, if necessary, a tri- or higher functional polycarboxylic acid such as trimellitic acid, pyromellitic acid or the like and tetracarboxylic acid may be used if it is 10 mol% or less based on the total carboxylic acid component. I can do it. In particular, a structure in which one or more acid components in which a part of an aromatic dicarboxylic acid is substituted with sulfonic acid or a salt thereof is included in one molecular chain, and the upper limit of the amount of these sulfonic acid substitutions (or groups of the salts) is preferable. For example, it is more preferable that it is copolymerized within a range soluble in an organic solvent in that it can be used by mixing with other organic solvent-soluble additives and resins. Preferred aromatic dicarboxylic acids containing these sulfonic acid substitutions (or salts thereof) include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, Examples thereof include 5 (4-sulfophenoxy) isophthalic acid and the like, ammonium salts thereof, and metal salts thereof such as lithium, potassium, magnesium, calcium, copper, and iron. Particularly preferred is 5-sodium sulfoisophthalic acid.

  Examples of the polyol component which is another raw material of the polyester include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, , 6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, hydroxypivalic acid neopentyl glycol ester, dimethylolheptane, 2,2, 4-trimethyl-1,3-pentanediol is mentioned. Diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol ethylene oxide adduct, neopentyl glycol propylene oxide adduct may be used as necessary.

  As aromatic-containing glycols, para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, bisphenol A, ethylene oxide adduct of bisphenol A and propylene Examples thereof include glycols obtained by adding 1 to several moles of ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols such as oxide adducts. Examples of the alicyclic diol component include tricyclodecane diol, tricyclodecane dimethylol, tricyclodecane dimethanol (TCD-M), cyclohexane diol, 1,4-cyclohexane dimethanol, hydrogenated bisphenol A, and hydrogenation. Examples thereof include ethylene oxide and propylene oxide adducts of bisphenol A. The polyester resin preferably has a glass transition temperature of 50 to 120 ° C., and a molecular weight of preferably 2,000 to 40,000, and more preferably 4,000 to 20,000 when the protective layer is transferred. Is better and more preferable.

  Further, by using an ionizing radiation curable resin, a protective layer having particularly excellent plasticizer resistance and scratch resistance can be obtained. As a specific example, there is one in which a radical polymerizable polymer or oligomer is crosslinked and cured by irradiation with ionizing radiation. At this time, if necessary, a photopolymerization initiator may be added and polymerized and cross-linked by an electron beam or ultraviolet rays. In addition, a known ionizing radiation curable resin can be used.

In order to impart light resistance to the printed matter, a protective layer containing an ultraviolet absorber and / or an ultraviolet blocking resin is also a preferred embodiment.
As the ultraviolet absorber, conventionally known inorganic ultraviolet absorbers and organic ultraviolet absorbers can be used. Organic UV absorbers include salicylates, benzophenones, benzotriazoles, triazines, substituted acrylonitriles, nickel chelates, hindered amines, and other non-reactive UV absorbers, and their non-reactive UV absorption For example, an addition polymerizable double bond such as a vinyl group, an acryloyl group, or a methacryloyl group, or an alcoholic hydroxyl group, an amino group, a carboxyl group, an epoxy group, an isocyanate group, or the like is introduced into the agent. A copolymerized or grafted plastic resin can be used as the ultraviolet blocking resin. Among these ultraviolet absorbers, benzophenone, benzotriazole, and triazine are particularly preferable.
In addition, a method of obtaining an ultraviolet blocking resin by dissolving an ultraviolet absorbent in a monomer or oligomer of a resin used for a protective layer and then polymerizing the monomer or oligomer is also disclosed (Japanese Patent Application Laid-Open No. 2006-21333). ). In this case, the ultraviolet absorber may be non-reactive.
Commercially available UV absorbers include Tinuvin-P (manufactured by Ciba Geigy), JF-77 (manufactured by Johoku Chemical), Sea Soap 701 (manufactured by Shiroishi Calcium), Sumisop 200 (manufactured by Sumitomo Chemical), and Biosoap 520 (manufactured by Kyodo Yakuhin). , ADK STAB LA-32 (manufactured by Asahi Denka) and the like.

  Depending on the characteristics of the dye used for image formation, these UV absorbers may be used in combination with different ones so as to cover the effective UV absorption wavelength range, or non-reactive UV absorbers may be used as UV absorbers. It is preferable to use a mixture of a plurality of different structures so as not to precipitate.

Examples of organic fillers and / or inorganic fillers include polyethylene wax, bisamide, nylon, acrylic resin, cross-linked polystyrene, silicone resin, silicone rubber, talc, calcium carbonate, titanium oxide, alumina, microsilica, colloidal silica, and other fine silica particles. It can be illustrated. In the thermal transfer sheet of the present invention, known materials can be suitably used without being limited thereto.
The organic filler and / or the inorganic filler preferably have a particle size of 10 μm or less, preferably in the range of 0.1 to 3 μm, good slipperiness and high transparency. The addition amount of the filler is preferably such that the transparency is maintained when transferred, and is preferably in the range of 0 to 100 parts by mass with respect to 100 parts by mass of the resin.

  The protective layer depends on the kind of the resin for forming the protective layer, but is formed by a method similar to the method for forming the thermal transfer layer, and a thickness of about 0.5 to 10 μm is preferable.

In the case where the protective layer is difficult to peel off from the support during transfer, it is also a preferred embodiment to form the release layer 4a between the support and the protective layer. The release layer is made of a material having excellent releasability such as waxes, silicone wax, silicone resin, fluorine resin, or a resin having a relatively high softening point that does not melt by the heat of the thermal head, for example, a cellulose resin. Conventionally, a coating liquid comprising an acrylic resin, a polyurethane resin, a polyvinyl acetal resin, an acrylic vinyl ether resin, a maleic anhydride resin, a silicone resin, a fluororesin, or a resin containing a heat release agent such as wax in these resins is used. It can form by apply | coating and drying by methods, such as a well-known gravure coat and a gravure reverse coat. Among the above resins, as the acrylic resin, a resin copolymerized with a simple substance such as acrylic acid or methacrylic acid or other monomers is preferable, and excellent in adhesion to the support and releasability from the protective layer. Yes. These resins may be used alone or in combination.
This release layer remains on the support side during printing (transfer).
The thickness of the layer is preferably about 0.5 to 5 μm. Matte the surface of the release layer by incorporating various particles in the release layer or by matting the surface of the release layer on the protective layer side so that the surface of the image receiving sheet after printing is matte Is also possible.

  A release layer may be formed between the transferable protective layer and the release layer. The release layer is transferred together with the protective layer. After transfer, it is the uppermost layer of the printed image-receiving sheet, and is formed from a resin having excellent transparency, abrasion resistance, and chemical resistance. Examples of the resin include an acrylic resin, an epoxy resin, a polyester resin, and a styrene resin. It is also possible to add fillers, waxes and the like.

It is preferable to provide the adhesive layer 4c on the protective layer as the uppermost layer of the transferable protective layer laminate. Thereby, the transferability of the protective layer can be improved. Known adhesives, heat-sensitive adhesives, and thermoplastic resins can be used for the adhesive layer. Examples include polyester resins, vinyl chloride-vinyl acetate copolymer resins, acrylic resins, and acrylic-ultraviolet absorbers. Examples thereof include resins having good adhesiveness during heating, such as copolymer resins, ultraviolet absorbing resins, butyral resins, epoxy resins, polyamide resins, vinyl chloride resins, and polycarbonate resins. Among these, a thermoplastic resin having a glass transition temperature of 40 ° C to 80 ° C is preferable.
When Tg is less than 40 ° C., the adhesiveness between the image to be coated and the transparent protective layer becomes insufficient, which tends to occur. When Tg is 80 ° C. or higher, the transferability of the transparent protective layer tends to be insufficient.
Particularly preferred are polyvinyl chloride resins, polyvinyl acetate resins, and vinyl chloride / vinyl acetate copolymer resins having a degree of polymerization of 50 to 300, more preferably 50 to 250.
As the ultraviolet absorbing resin, for example, a resin obtained by reacting and bonding a reactive ultraviolet absorber to a thermoplastic resin or an ionizing radiation curable resin can be used. More specifically, for conventionally known non-reactive organic ultraviolet absorbers such as salicylates, phenyl acrylates, benzophenones, benzotriazoles, coumarins, triazines, nickel chelates, substituted acrylonitriles, hindered amines, etc. Addition of polymerizable groups such as addition polymerizable double bonds (for example, vinyl group, acryloyl group, methacryloyl group), alcoholic hydroxyl group, amino group, carboxyl group, epoxy group, isocyanate group, thermoplastic Resins obtained by reacting and bonding to resins or ionizing radiation curable resins can be used.

  The adhesive layer is composed of the above-described resins, organic ultraviolet absorbers such as benzophenone compounds, benzotriazole compounds, oxalic acid anilide compounds, cyanoacrylate compounds, salicylate compounds, zinc, titanium, cerium, and the like. Additives of fine particles having an inorganic ultraviolet absorbing ability such as oxides of tin, iron and the like can be added. Further, as an additive, a coloring pigment, a white pigment, an extender pigment, a filler, an antistatic agent, an antioxidant, a fluorescent whitening agent, and the like can be used as necessary. By applying and drying a resin that constitutes the adhesive layer as described above and, if necessary, a coating liquid to which the above additives are added, a thickness of preferably about 0.5 to 10 μm in a dry state. To form an adhesive layer. Preferably it is 0.5-5 micrometers, More preferably, it is 0.5-3 micrometers.

The back surface of the thermal transfer sheet travels while being heated in direct contact with a heating device such as a thermal head. For this reason, it is preferable to provide the back layer 5 in order to prevent thermal fusion between the back surface of the support and a heating device such as a thermal head and to smooth the running.
For the back layer, cellulose resins such as ethyl cellulose, hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, nitrocellulose, vinyl resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, etc. Resin, polymethyl methacrylate, polyethyl acrylate, polyacrylamide, acrylic resin such as acrylonitrile-styrene copolymer, polyamide resin, polyvinyl toluene resin, coumarone indene resin, polyester resin, polyurethane resin, silicone modified or fluorine A simple substance or a mixture of natural or synthetic resins such as modified urethane resins and silicone resins can be used.

In order to improve the heat resistance of the back layer, it is also a preferred embodiment to use a crosslinking agent as a crosslinked resin layer.
Furthermore, in order to improve the running property, it is preferable that the back layer contains a solid or liquid release agent or lubricant. Known ones can be used, for example, zinc stearate, stearamide, kaunauba wax, mondan wax, polyethylene wax, paraffin wax and other waxes, higher fatty acid alcohol, organopolysiloxane, anionic interface Activators, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorosurfactants, organic carboxylic acids and their derivatives, fluororesins, silicone resins, phosphate ester compounds, organic or inorganic And the like.

  Such a back layer can be formed using a normal coating method. The thickness is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm, and particularly preferably 0.5 to 3 μm.

A preferred production method (embodiment) of the thermal transfer sheet used in the image forming method of the present invention will be described below.
For example, when the yellow, magenta, and cyan thermal transfer layers are formed on the same support in a surface sequential manner, the belt-shaped support sheet is provided at different positions in the longitudinal direction of the support sheet. In addition, yellow, magenta, and cyan thermal transfer layer regions (dye layers) and detection marks provided at ends of the thermal transfer layer region of the sheet are provided. The detection mark is provided at a right angle to the longitudinal direction of the sheet.
A known coating method can be used for forming these layers. Examples of the method include roll coating, bar coating, gravure coating, and gravure reverse coating.
As an example of a gravure printing method using a printing cylinder, first, a yellow thermal transfer layer area is printed with a yellow printing cylinder, then a magenta thermal transfer layer area is printed with a magenta printing cylinder, and further, a cyan thermal transfer layer area is printed with a cyan printing cylinder. To print. Then, the detection mark is finally printed at once by the mark printing cylinder.

  It is also possible to perform printing by providing plate portions of a plurality of thermal transfer layers on the same printing cylinder (multi-sided attachment). However, with this method, the thickness and the like of the manufactured thermal transfer layer may differ slightly due to manufacturing errors of each plate portion. When printing is performed using the thermal transfer sheet thus prepared (transferred to a thermal transfer image receiving sheet), a difference in hue tends to occur. In order to prevent this, it is possible to print a different detection mark for at least one region of each thermal transfer layer region or for each set of the thermal transfer layer regions.

  In the above description, the case where the thermal transfer layer regions of yellow, magenta, and cyan are provided has been described. However, the present invention is not limited to such a configuration, and in addition to the three color thermal transfer layers, a black layer and / or A transferable protective layer laminate may be provided.

Next, the thermal transfer image receiving sheet (image receiving sheet) used in the image forming method of the present invention will be described.
The heat-sensitive transfer image-receiving sheet used in the present invention has at least one dye-receiving layer (receiving layer) on a support, and at least one heat-insulating layer (porous layer) between the support and the receiving layer. It is preferable to have. In addition, an underlayer such as a white background adjusting layer, a charge adjusting layer, an adhesive layer, or a primer layer may be formed between the receiving layer and the heat insulating layer. These layers are preferably formed by aqueous simultaneous multi-layer application using an aqueous coating solution. “Aqueous” here means that 60% by mass or more of the solvent (dispersion medium) of the coating solution is water. Components other than water in the coating solution include methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, ethyl acetate, diacetone alcohol, furfuryl alcohol, benzyl alcohol, diethylene glycol monoethyl ether, oxyethylphenyl A water-miscible organic solvent such as ether can be used.

  The receiving layer and the heat insulating layer are preferably formed by simultaneous multilayer coating. Furthermore, it is preferably formed by aqueous simultaneous multilayer coating. When the underlayer is included, the receiving layer, the underlayer and the heat insulating layer can be formed by simultaneous multilayer coating.

  It is preferable that a curl adjusting layer, a writing layer, and a charge adjusting layer are formed on the back side of the support. Each layer on the back side of the support can be applied by a general method such as roll coating, bar coating, gravure coating, or gravure reverse coating.

In the present invention, the dye receiving layer is formed by the coating method using the aqueous coating liquid described above. In this case, the dye receiving layer is formed from a water-soluble polymer compound and / or a polymer latex.
In the present invention, the water-soluble polymer compound means a polymer compound that can be dissolved in 30% by mass or more in the above-described solvent in which 60% by mass or more is water. Examples include natural polymer compounds such as gelatin and starch, and synthetic polymer compounds such as polyvinyl alcohol and water-soluble polyester.

In the image forming method of the present invention, a polymer latex is also preferably used for the dye-receiving layer of the thermal transfer image-receiving sheet. The polymer latex that can be used in the receptor layer is preferably a polymer in which a hydrophobic polymer containing water-insoluble vinyl chloride as a monomer unit is dispersed as fine particles in a water-soluble dispersion medium. As the dispersion state, the polymer is emulsified in a dispersion medium, the emulsion is polymerized, the micelle is dispersed, or the polymer molecule has a partially hydrophilic structure and the molecular chain itself is molecularly dispersed. Anything may be used. For polymer latex, Tadashi Okuda, Hiroshi Inagaki, “Synthetic Resin Emulsion”, published by Kobunshi Publishing (1978); Takaaki Sugimura, Akio Kataoka, Junichi Suzuki, Keiji Kasahara, “Application of Synthetic Latex”, Takashi Published by Molecular Publications (1993); Soichi Muroi, “Chemistry of Synthetic Latex”, published by High Polymer Publications (1970); 2004) and JP-A-64-538. The average particle size of the dispersed particles is preferably about 1 to 50000 nm, more preferably about 5 to 1000 nm.
The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution.

  The polymer latex may be a normal uniform structure polymer latex or a so-called core / shell type latex. At this time, it may be preferable to change the glass transition temperature between the core and the shell. The glass transition temperature of the polymer latex used in the present invention is preferably −30 ° C. to 100 ° C., more preferably 0 ° C. to 80 ° C., further preferably 10 ° C. to 70 ° C., and particularly preferably 15 ° C. to 60 ° C.

  As the polymer latex used in the receiving layer, polyvinyl chlorides and copolymers containing vinyl chloride as monomer units, for example, vinyl chloride vinyl acetate copolymers and vinyl chloride acrylic copolymer polymers can be preferably used. In this case, the ratio of the vinyl chloride monomer is preferably 50% by mass to 95% by mass. These polymers may be linear polymers, branched polymers, crosslinked polymers, so-called homopolymers obtained by polymerizing a single monomer, or two or more types of monomers. It may be a polymerized copolymer. In the case of a copolymer, it may be a random copolymer or a block copolymer. The number average molecular weight of these polymers is usually 5,000 to 1,000,000, preferably 10,000 to 500,000. When the molecular weight is too small, the layer containing the latex may have insufficient mechanical strength, and when it is too large, the film formability may be poor. A crosslinkable polymer latex is also preferably used.

  Polymer latexes that can be used are also commercially available, and the following polymers can be used. Examples include G351 and G576 manufactured by Nippon Zeon Co., Ltd., Vinibrand 240, 270, 277, 375, 386, 609, 550, 601, 602, 630, 660, 671, 683, 680 manufactured by Nissin Chemical Industry Co., Ltd. 680S, 681N, 685R, 277, 380, 381, 410, 430, 432, 860, 863, 865, 867, 900, 900GT, 938, 950, etc. (all are trade names).

These polymer latexes may be used alone or in combination of two or more as required. In the receiving layer, the copolymer latex containing vinyl chloride as a monomer unit is preferably 50% by mass or more in terms of the total solid content in the layer.
In the present invention, it is preferable to prepare the receptor layer by applying an aqueous coating solution and then drying it.

The minimum film-forming temperature (MFT) of the polymer latex is usually −30 ° C. to 90 ° C., preferably about 0 ° C. to 70 ° C. In order to control the minimum film forming temperature, a film forming aid may be added. A film-forming aid, also called a temporary plasticizer, is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of polymer latex. For example, Soichi Muroi, “Chemistry of Synthetic Latex”, published by Kobunshi Shuppankai (1970) )It is described in. Although the following compounds can be mentioned as preferable film-forming aids, the film-forming aids are not limited to the following specific examples.
Z-1: benzyl alcohol Z-2: 2,2,4-trimethylpentanediol-1,3-monoisobutyrate Z-3: 2-dimethylaminoethanol Z-4: diethylene glycol

  The above polymer latex may be used (blended) with other polymer latex. Preferable examples of such polymer latex include polylactic acid esters, polyurethanes, polycarbonates, polyesters, polyacetals, and SBRs. Among these, polyesters and polycarbonates can be mentioned.

  Furthermore, the polymer latex may be used in combination with any polymer together with the polymer latex. The polymer that can be used in combination is preferably transparent or translucent and colorless. Natural resins, polymers and copolymers, synthetic resins, polymers and copolymers, and other media for forming films such as gelatins and polyvinyl alcohol , Hydroxyethylcelluloses, cellulose acetates, cellulose acetate butyrate, polyvinylpyrrolidones, casein, starch, polyacrylic acids, polymethylmethacrylic acids, polyvinylchlorides, polymethacrylic acids, styrene-maleic anhydride copolymers Styrene-acrylonitrile copolymers, styrene-butadiene copolymers, polyvinyl acetals (eg, polyvinyl formal and polyvinyl butyral), polyesters, polyurethanes, Phenoxy resins, polyvinylidene chlorides, polyepoxides, polycarbonates, polyvinyl acetates, polyolefins, polyamides such. The binder may be formed from water, an organic solvent, or an emulsion.

  The binder preferably has a glass transition temperature (Tg) in the range of −30 ° C. to 70 ° C., more preferably in the range of −10 ° C. to 50 ° C., and still more preferably in the range of 0 ° C. to 0 ° C. in view of processing brittleness and image storage stability. It is in the range of 40 ° C. It is also possible to use a blend of two or more polymers as the binder, and in this case, it is preferable that the weighted average Tg in consideration of the composition falls within the above range. Moreover, when phase-separating or having a core-shell structure, the weighted average Tg is preferably within the above range.

This glass transition temperature (Tg) can be calculated by the following formula.
1 / Tg = Σ (Xi / Tgi)
Here, it is assumed that n monomer components from i = 1 to n are copolymerized in the polymer. Xi is the mass fraction of the i-th monomer (ΣXi = 1), and Tgi is the glass transition temperature (absolute temperature) of the homopolymer of the i-th monomer. However, Σ is the sum from i = 1 to n. The homopolymer glass transition temperature value (Tgi) of each monomer may be the value of “Polymer Handbook (3rd Edition)” (by J. Brandrup, EH Immergut (Wiley-Interscience, 1989)). However, the glass transition temperature of the ink layer usually employs a value obtained by actual measurement.

  The polymer used for the binder can be easily obtained by solution polymerization method, suspension polymerization method, emulsion polymerization method, dispersion polymerization method, anion polymerization method, cationic polymerization, etc., but the emulsion polymerization method obtained as a latex is most preferable. . Also preferred is a method of preparing a polymer in a solution and neutralizing or adding an emulsifier and then adding water and forcibly stirring to prepare an aqueous dispersion. In the emulsion polymerization method, for example, water or a mixed solvent of water and an organic solvent miscible with water (for example, methanol, ethanol, acetone, etc.) is used as a dispersion medium, and the monomer is 5 to 150% by mass with respect to the dispersion medium. An emulsifier and a polymerization initiator are used with respect to the mixture and the total amount of monomers, and the polymerization is usually carried out with stirring at about 30 to 100 ° C., preferably 60 to 90 ° C. for 3 to 24 hours. Various conditions such as the dispersion medium, the monomer concentration, the initiator amount, the emulsifier amount, the dispersant amount, the reaction temperature, and the monomer addition method are appropriately set in consideration of the type of monomer used. Moreover, it is preferable to use a dispersing agent as needed.

  As the polymer latex, an aqueous solvent can be used as a solvent in the coating solution, but a water-miscible organic solvent may be used in combination. Examples of the water-miscible organic solvent include alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol, cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, ethyl acetate and dimethylformamide. The amount of these organic solvents added is preferably 50% by mass or less, more preferably 30% by mass or less of the solvent.

  The polymer latex contained in each layer of the heat-sensitive transfer image-receiving sheet used in the image forming method of the present invention preferably has a polymer concentration of 10 to 70% by mass, more preferably 20 to 60% by mass, especially 30. It is preferable that it is -55 mass%. The polymer latex in the heat-sensitive transfer image-receiving sheet of the present invention includes a gel or dried film formed by drying a part of the solvent after coating.

In the present invention, it is also a preferred embodiment to contain an emulsified dispersion (emulsion) in the receiving layer. Here, “emulsification” follows the commonly used definition. For example, according to the Dictionary of Chemistry (Kyoritsu Shuppan Co., Ltd.), “emulsification” is “a phenomenon in which another liquid that does not dissolve in one liquid is dispersed as fine particles and an emulsion is formed”. The “emulsified dispersion” refers to “liquid droplets that are dispersed in another liquid that does not dissolve them”. In the present invention, a preferable “emulsified dispersion” is an “oil droplet dispersion dispersed in water”. The content of an emulsified dispersion in the image-receiving sheet of the present invention is preferably contained 0.03g ^{/ m 2} ~25.0g ^/ m 2 in the heat-sensitive transfer image-receiving ^sheet, 1.0g / m 2 ^~20.0g / More preferably, m ^{2 is} included.

In the present invention, it is preferable that a high boiling point solvent is contained in the oil-soluble component of the emulsified dispersion. Preferred high boiling point solvents include phthalates (dibutyl phthalate, dioctyl phthalate, di-2-ethylhexyl phthalate, etc.), phosphoric acid or phosphonic esters (triphenyl phosphate, tricresyl phosphate, triphosphate phosphate). 2-ethylhexyl, etc.), fatty acid esters (di-2-ethylhexyl succinate, tributyl citrate, etc.), benzoates (2-ethylhexyl benzoate, dodecyl benzoate, etc.), amides (N, N-diethyl, etc.) Dodecanamide, N, N-dimethyloleamide, etc.), alcohol or phenols (isostearyl alcohol, 2,4-di-tert-amylphenol, etc.), anilines (N, N-dibutyl-2-butoxy-5-) tert-octylaniline), chlorinated paraffins, hydrocarbons ( Decylbenzene, diisopropylnaphthalene, etc.), carboxylic acids (2- (2,4-di-tert-amylphenoxy) butyric acid, etc. More preferably, the high boiling point solvent is phosphoric acid or phosphonic acid esters (phosphoric acid triphosphate). Phenyl, tricresyl phosphate, tri-2-ethylhexyl phosphate, etc. In addition, as an auxiliary solvent, an organic solvent having a boiling point of 30 ° C. or higher and 160 ° C. or lower (ethyl acetate, butyl acetate, methyl ethyl ketone, cyclohexanone, methyl cellosolve acetate, dimethyl) The high boiling point solvent is preferably contained in the emulsion dispersion in an amount of 3.0 to 25% by mass, more preferably 5.0 to 20% by mass.
Further, the emulsified dispersion preferably contains an image fastening agent and an ultraviolet absorber. As these compounds, the general formulas (B), (Ph), (E-1) to (E-3), (TS-I) to (TS-VII) described in JP-A-2004-361936, A compound represented by any one of (TS-VIIIA) and (UA) to (UE) is preferable. Further, it may contain a water-insoluble and organic solvent-soluble homopolymer or copolymer (preferably the compounds described in paragraph Nos. 0208 to 0234 of JP-A No. 2004-361936).

  In order to improve the sensitivity of the receiving layer, a plasticizer (high boiling point organic solvent) can also be added. Examples of such plasticizers include monomeric plasticizers such as phthalic acid esters, phosphoric acid esters, adipic acid esters, and sebacic acid esters, and polyester-type plasticizers obtained by polymerizing adipic acid, sebacic acid, and propylene glycol. In general, those which can be used as plasticizers for vinyl chloride resins are mentioned. The plasticizers listed above generally have a low molecular weight, but other olefin-based special copolymer resins used as vinyl chloride polymer plasticizers can also be used. Resins used for such applications are commercially available as Elvalloy 741, Elvalloy 742, Elvalloy HP443, Elvalloy HP553, Elvalloy EP4015, Elvalloy EP4043, Elvalloy EP4051 (all trade names, manufactured by Mitsui DuPont Polychemical Co., Ltd.). You can use what you have. Such a plasticizer can be added in an amount of about 100% by mass with respect to the resin, but the amount used is preferably 30% by mass or less in terms of bleeding of the printed matter. These plasticizers are introduced into the receiving layer in the form of the aforementioned emulsified dispersion.

If the image-receiving surface of the heat-sensitive transfer image-receiving sheet does not have sufficient peeling performance, the heat-sensitive transfer sheet and the heat-sensitive transfer image-receiving sheet (image-receiving sheet) are fused by heat from the thermal head during image formation, and a large peeling sound is generated during peeling. In addition, there arises a problem of so-called abnormal transfer in which the thermal transfer layer is transferred together with the layer, or the receiving layer is peeled off from the substrate. As a method for solving the above problem of peelability, there are known a method of internally adding various release agents into the receiving layer, or a method of separately providing a release layer on the receiving layer. In the present invention, it is preferable to use a release agent in the receiving layer in order to ensure the releasability between the heat-sensitive transfer sheet and the image receiving sheet during image printing.
Examples of the release agent include solid waxes such as polyethylene wax, amide wax, Teflon (registered trademark) powder (Teflon (registered trademark)); silicone oil, phosphate ester compound, fluorine surfactant, silicone Surfactants and other release agents known in the art can be used, and fluorine compounds represented by fluorine surfactants, silicone surfactants, silicone oils and / or cured products thereof, etc. These silicone compounds are preferably used.

  As the silicone oil, straight silicone oil, modified silicone oil or a cured product thereof can be used. Straight silicone oils include dimethyl silicone oil, methylphenyl silicone oil, and methyl hydrogen silicone oil. Examples of dimethyl silicone oil include KF96-10, KF96-100, KF96-1000, KF96H-10000, KF96H-12500, and KF96H. -100,000 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like, and examples of dimethyl silicone oil include KF50-100, KF54, KF56 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.). Can be mentioned.

  The modified silicone oil can be classified into a reactive silicone oil and a non-reactive silicone oil. The reactive silicone oil includes amino modification, epoxy modification, carboxyl modification, hydroxy modification, methacryl modification, mercapto modification, phenol modification, one-terminal reactivity and heterofunctional modification. As amino-modified silicone oil, KF-393, KF-857, KF-858, X-22-3680, X-22-3801C, KF-8010, X-22-161A, KF-8012 (all trade names, Shin-Etsu Chemical Co., Ltd.) and the like, and epoxy-modified silicone oils include KF-100T, KF-101, KF-60-164, KF-103, X-22-343, X-22-3000T ( All of them are trade names, manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of the carboxyl-modified silicone oil include X-22-162C (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of the hydroxy-modified silicone oil include X-22-160AS, KF-6001, KF-6002, KF-6003, X-22-170DX, X-22-176DX, X-22-176D, X-22-176DF (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like, methacryl-modified silicone oil X-22-164A, X-22-164C, X-24-8201, X-22-174D, X-22-2426 (all are trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. .

  The reactive silicone oil can be used after being cured, and can be classified into a reaction curable type, a photo curable type, a catalyst curable type, and the like. Of these, reaction-curable silicone oils are particularly preferable. As the reaction-curable silicone oils, those obtained by reaction-curing amino-modified silicone oil and epoxy-modified silicone oil are preferable. Further, as the catalyst curable type or photo curable type silicone oil, KS-705F-PS, KS-705F-PS-1, KS-770-PL-3 [catalyst curable type silicone oil: all trade names, Shin-Etsu Chemical Co., Ltd. KS-720, KS-774-PL-3 [photocured silicone oil: trade names, manufactured by Shin-Etsu Chemical Co., Ltd.], and the like. The addition amount of these curable silicone oils is preferably 0.5 to 30% by mass of the resin constituting the image receiving layer. The release agent is usually used in an amount of 2 to 4% by mass, preferably about 2 to 3% by mass, based on 100 parts by mass of the polyester resin. If the amount is too small, the releasability cannot be ensured, and if the amount is too large, the protective layer will not be transferred to the image receiving sheet.

  Non-reactive silicone oils include polyether modification, methylstyryl modification, alkyl modification, higher fatty acid ester modification, hydrophilic special modification, higher alkoxy modification, fluorine modification and the like. Examples include polyether-modified silicone (KF-6012, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), and methylstil-modified silicone silicone oil (24-510, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.). Can be mentioned. Moreover, the modified silicone represented by either of the following general formulas 1-3 can also be used.

一般式１中、Ｒは水素原子、またはアリール基若しくはシクロアルキル基で置換されてもよい直鎖または分岐のアルキル基を表す。ｍ、ｎはそれぞれ独立に２０００以下の整数を表し、ａ、ｂはそれぞれ独立に３０以下の整数を表す。

In general formula 1, R represents a hydrogen atom or a linear or branched alkyl group which may be substituted with an aryl group or a cycloalkyl group. m and n each independently represent an integer of 2000 or less, and a and b each independently represent an integer of 30 or less.

  In General Formula 2, R represents a hydrogen atom or a linear or branched alkyl group which may be substituted with an aryl group or a cycloalkyl group. m represents an integer of 2000 or less, and a and b each independently represent an integer of 30 or less.

In General Formula 3, R represents a hydrogen atom or a linear or branched alkyl group which may be substituted with an aryl group or a cycloalkyl group. m and n each independently represent an integer of 2000 or less, and a and b each independently represent an integer of 30 or less. R ¹ represents a single bond or a divalent linking group, E represents an ethylene group or a substituted ethylene group, and P represents a propylene group or a substituted propylene group.

Silicone oils such as those described above are described in “Silicone Handbook” (published by Nikkan Kogyo Shimbun Co., Ltd.), and are described in JP-A-8-108636 and JP-A-2002-264543 as curing technologies for curable silicone oils. The technique can be preferably used.
Note that abnormal transfer may occur in which the dye binder is taken on the receiving layer in the highlight portion of the monochromatic print. In addition, conventionally, addition polymerization type silicones generally proceed with a curing reaction in the presence of a catalyst, and almost all of iron group and platinum group 8 transition metal complexes are effective as curing catalysts. However, in general, platinum compounds are most efficient, and platinum catalysts which are platinum complexes soluble in silicone oil are usually preferably used. As an addition amount necessary for the reaction, about 1 to 100 ppm is sufficient.

  This platinum catalyst has a strong interaction with organic compounds containing multiple bonds, such as organic compounds containing N, P, S, etc., heavy metal ionic compounds such as Sn, Pb, Hg, Bi, As, acetylene groups, etc. When used together with the above compounds (catalyst poisons), the ability to hydrosilylate as a catalyst is lost, and the function as a curing catalyst is lost, so there is a drawback of causing poor curing of the silicone ("Silicone Handbook" Nikkan Kogyo). Newspaper company). Therefore, such a poorly cured addition polymerization type silicone does not exhibit any peeling performance even when used in the receiving layer. It is conceivable to use an isocyanate compound as a curing agent that reacts with active hydrogen, and this isocyanate compound and the organotin compound as a catalyst thereof are catalyst poisons of a platinum catalyst. Therefore, conventionally, the addition polymerization type silicone is not used in combination with an isocyanate compound, and thus is not used in combination with a modified silicone having active hydrogen that exhibits a peeling performance when cured with an isocyanate compound. .

  However, 1) the ratio of the reactive group equivalent of the curing agent that reacts with active hydrogen and the reactive group equivalent of both the thermoplastic resin and the modified silicone having active hydrogen is 1: 1 to 10: 1. 2) Addition polymerization type By setting the platinum catalyst amount with respect to silicone to 100 to 10,000 ppm as platinum atoms of the platinum catalyst, it is possible to prevent curing of the addition polymerization type silicone. When the reactive group equivalent of the curing agent that reacts with the active hydrogen of 1) is 1 or less, the curing amount of the active hydrogen-containing silicone and the active hydrogen of the thermoplastic resin is small, and good release performance is obtained. Absent. On the other hand, when the equivalent ratio is 10 or more, the usable time of the ink of the receiving layer coating liquid is short and cannot be used substantially. Further, when the platinum catalyst amount of 2) is 100 ppm or less, the activity is lost due to the catalyst poison, and when it is 10000 ppm or more, the ink usable time of the receiving layer coating liquid is short and cannot be used.

The coating amount of the receiving layer is preferably 0.5 to 10 g / m ² (in terms of solid content, hereinafter the coating amount in the present invention is a numerical value in terms of solid content unless otherwise specified).

The cured modified silicone oil may be added to the release layer formed on the receiving layer without being added to the receiving layer. In this case, the receiving layer may be formed using one or more kinds of thermoplastic resins as described above, or a receiving layer to which silicone is added may be used. The release layer contains a curable modified silicone, and the type and usage of the silicone used are the same as those used for the receiving layer. Further, when a catalyst or a retarder is used, it is the same as that added to the receiving layer. The release layer may be formed only from silicone, or may be used as a binder resin by mixing with a compatible resin. The thickness of the release layer is about 0.001 to 1 g / m ² .

  Fluorosurfactants include Fluorad FC-430 and FC-431 (both trade names, manufactured by 3M).

  A base layer is preferably formed between the receptor layer and the support. For example, a white background adjustment layer, a charge adjustment layer, an adhesive layer, and a primer layer are formed. These layers can be formed in the same manner as described in, for example, Japanese Patent No. 3585599 and Japanese Patent No. 2925244.

  The heat insulating layer serves to protect the support from heat during heat transfer using a thermal head or the like. Moreover, since it has high cushioning properties, a thermal transfer image-receiving sheet with high printing sensitivity can be obtained even when paper is used as the substrate. The heat insulating layer may be one layer or two or more layers. The heat insulating layer is provided on the support side from the receptor layer.

  In the image forming method of the present invention, it is preferable that the heat-insulating layer of the heat-sensitive transfer image-receiving sheet used therein contains a hollow polymer. This hollow polymer is a polymer particle having independent pores inside the particle, for example, [1] a dispersion medium such as water is contained inside the partition formed by polystyrene, acrylic resin, styrene-acrylic resin, etc. After coating and drying, non-foamed hollow particles in which the dispersion medium in the particles evaporates outside the particles and the inside of the particles becomes hollow, [2] low boiling point liquids such as butane and pentane, and polyvinylidene chloride, polyacrylonitrile, poly Foamed micro, which is covered with a resin made of either acrylic acid or polyacrylic ester, or a mixture or polymer thereof, and the inside is hollowed by the expansion of the low-boiling liquid inside the particles by heating after coating. Balloons, [3] Microballoons obtained by heating and foaming the above [2] in advance to form hollow polymers, and the like.

The particle size of these hollow polymers is preferably 0.1 to 20 μm, more preferably 0.1 to 2 μm, still more preferably 0.1 to 1 μm, and particularly preferably 0.2 to 0.8 μm. If the size is too small, the hollowness tends to decrease and the desired heat insulating property cannot be obtained.If the size is too large, the particle diameter of the hollow polymer is too large for the film thickness of the heat insulating layer to obtain a smooth surface. This is because it becomes difficult to cause coating failure due to coarse particles.
The hollow ratio of the hollow polymer is preferably about 20 to 70%, more preferably 20 to 50%. This is because when the hollow ratio is less than 20%, sufficient heat insulation cannot be obtained, and when the hollow ratio is excessively high, the ratio of incomplete hollow particles increases within a preferable particle size range, and sufficient film strength is obtained. This is because it cannot be obtained.
The hollow ratio of the hollow polymer in the present invention is a value P calculated by the following formula (a) in a transmission image taken from a transmission micrograph of the hollow particles.

  In the above formula (a), Rai represents the equivalent circle diameter of the inner contour (indicating the hollow portion contour) of the two contours constituting the image of the specific particle i, and Rbi represents the image of the specific particle i. Of the two contours to be constructed, the equivalent circular diameter of the outer contour (indicating the particle outer shape) is represented, n represents the number of measured particles, and n ≧ 300.

  The glass transition temperature (Tg) of the hollow polymer is preferably 70 ° C. or higher, and more preferably 100 ° C. or higher. Two or more types of hollow polymers can be mixed and used as necessary.

  Such hollow polymers are commercially available, and specific examples of the above [1] include Law and Haas Ropaque 1055, Dainippon Ink Boncoat PP-1000, JSR SX866 (B), Nippon Zeon Nippon MH5055 (both are trade names). Specific examples of [2] include F-30 and F-50 (both trade names) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. Specific examples of [3] include F-30E manufactured by Matsumoto Yushi Seiyaku Co., Ltd., EXPANSELL 461DE, 551DE, and 551DE20 (all trade names) manufactured by Nippon Ferrite Co., Ltd. Among these, the hollow polymer of the series [1] can be more preferably used, and further this polymer latex can be preferably used.

  The heat insulating layer containing the hollow polymer preferably contains a water-dispersed resin or a water-soluble resin as a binder resin as a binder resin. Examples of the binder resin used in the present invention include acrylic resins, styrene-acrylic copolymers, polystyrene resins, polyvinyl alcohol resins, vinyl acetate resins, ethylene-vinyl acetate copolymers, vinyl chloride vinyl acetate copolymers, and styrene. Known resins such as butadiene copolymers, polyvinylidene chloride resins, cellulose derivatives, casein, starch, and gelatin can be used. In the present invention, it is particularly preferable to use gelatin. These resins can be used alone or in combination.

  The solid content of the hollow polymer in the heat insulating layer is preferably between 5 and 2000 parts by mass, and preferably between 5 and 1000 parts by mass when the solid content of the binder resin is 100 parts by mass. More preferably, it is more preferably between 5 and 400 parts by mass. Moreover, 1-70 mass% is preferable, and, as for the mass ratio which occupies with respect to the coating liquid of the solid content of a hollow polymer, 10-40 mass% is more preferable. If the ratio of the hollow polymer is too small, sufficient heat insulation cannot be obtained, and if the ratio of the hollow polymer is too large, the binding force between the hollow polymers is lowered, sufficient film strength cannot be obtained, and scratch resistance is obtained. Getting worse.

  The heat-sensitive transfer image-receiving sheet used in the image forming method of the present invention preferably has at least one heat insulating layer containing a hollow polymer and a hydrophilic polymer between the receiving layer and the support, and the layer is a heat insulating layer. More preferably, at least one of the hydrophilic polymers contained in the heat insulating layer is particularly preferably gelatin. At this time, it is preferable that the heat insulating layer does not contain a dye dyeable resin other than the hollow polymer. The dye dyeable resin refers to a preferable resin used for the dye-receiving layer of the thermal transfer image-receiving sheet.

  The thickness of the heat insulating layer containing the hollow polymer is preferably 5 to 50 μm, and more preferably 5 to 40 μm.

The porosity of the heat insulating layer calculated from the thickness of the heat insulating layer containing the hollow polymer and the solid coating amount of the heat insulating layer containing the hollow polymer is preferably 10 to 70%, and more preferably 15 to 60%. When the porosity of the heat insulating layer is less than 10%, sufficient heat insulating properties cannot be obtained, and when it is 70% or more, the binding force between the hollow polymers is lowered, and sufficient film strength cannot be obtained, and the scratch resistance is deteriorated.
In the present invention, the porosity of the heat insulating layer is a value V calculated by the following equation (b).

[Formula 2]
Formula (b)
V = 1−L / L × Σgi · di

  In the above formula (b), L represents the film thickness of the heat insulating layer, gi represents the solid coating amount of the specific material i constituting the heat insulating layer, and di represents the specific gravity of the specific material i. Here, when di represents the specific gravity of the hollow polymer, di represents the specific gravity of the wall material of the hollow polymer.

  An undercoat layer may be formed between the receiving layer and the heat insulating layer. For example, a white background adjusting layer, a charge adjusting layer, an adhesive layer, and a primer layer are formed. About these layers, it can be set as the structure similar to what was described, for example in patent 3585599, patent 2925244, etc.

  In the present invention, a water-resistant support is used as the support. By using a water-resistant support, it is possible to prevent moisture from being absorbed into the support, and to prevent a change in performance of the receiving layer over time. As the water-resistant support, for example, coated paper or laminated paper can be used.

  The thickness of the support is preferably 25 μm to 300 μm, more preferably 50 μm to 260 μm, and still more preferably 75 μm to 220 μm. Various stiffnesses can be used according to the purpose, and the support for a photographic image receiving sheet for electrophotography is close to a support for color silver halide photography. Those are preferred.

  If the support is exposed as it is, the thermal transfer image-receiving sheet may be curled due to the humidity and temperature in the environment. Therefore, it is preferable to form a curl adjusting layer on the back side of the support. The curl adjusting layer not only prevents the image receiving sheet from curling but also serves as a waterproof. For the curl adjusting layer, polyethylene laminate, polypropylene laminate, or the like is used. Specifically, it can be formed in the same manner as described in, for example, JP-A Nos. 61-110135 and 6-202295.

  An inorganic oxide colloid, an ionic polymer, or the like can be used for the writing layer and the charge adjusting layer. As the antistatic agent, for example, a cationic antistatic agent such as a quaternary ammonium salt or a polyamine derivative, an anionic antistatic agent such as an alkyl phosphate, or a nonionic antistatic agent such as a fatty acid ester can be used. . Specifically, it can be formed in the same manner as that described in, for example, Japanese Patent No. 3585585.

Hereinafter, a preferable production method as an embodiment of the thermal transfer image-receiving sheet of the present invention will be described.
The heat-sensitive transfer image-receiving sheet of the present invention can be formed by coating at least one receiving layer, intermediate layer and heat insulating layer on a support.
When manufacturing a heat-sensitive transfer image-receiving sheet having a multilayer structure comprising a plurality of layers having different functions (such as a bubble layer, a heat insulating layer, an intermediate layer, and a receiving layer) on a support, Japanese Patent Application Laid-Open Nos. 2004-106283 and 2004-2004. It is known that each layer is successively coated as shown in each publication such as 181888, 2004-345267, or the like, and each layer is applied on a support in advance. . On the other hand, it is known in the photographic industry that productivity is greatly improved, for example, by applying a plurality of layers simultaneously. For example, U.S. Pat. Nos. 2,761,791, 2,681,234, 3,508,947, 4,457,256, 3,993,019, JP 63-54975, JP-A-61-278848, 55-86557, 52-31727, 55-142565, 50-43140, 63-80872, 54-54020, Special No. 5-104061, No. 5-127305, Japanese Examined Patent Publication No. 49-7050, or the specification of Edgar B. et al. The so-called slide coating method (slide coating method) and curtain coating method (curtain coating method) described in Guoff et al., “Coating and Drying Defects: Troubleshooting Operating Problems”, John Wiley & Sons, 1995, pages 101 to 103, etc. Are known.
By using the simultaneous multilayer coating for the production of a multi-layer image-receiving sheet, productivity can be greatly improved and image defects can be greatly reduced.

The plurality of layers can be composed mainly of a resin. The coating solution for forming each layer is preferably water-dispersed latex. The solid content mass of the latex resin in the coating solution of each layer is preferably in the range of 5 to 80%, particularly preferably in the range of 20 to 60%. The average particle size of the resin contained in the water-dispersed latex is 5 μm or less and particularly preferably 1 μm or less. The water-dispersed latex may contain a known additive such as a surfactant, a dispersant, and a binder resin as necessary.
It is preferable to solidify quickly after forming a laminate of a plurality of layers on a support by the method described in US Pat. No. 2,761,791. As an example, in the case of a multilayer structure solidified by a resin, it is preferable to quickly raise the temperature after forming a plurality of layers on the support. When a binder that gels at a low temperature such as gelatin is included, it may be preferable to quickly lower the temperature after forming a plurality of layers on the support.

In the heat-sensitive transfer sheet to the heat-sensitive transfer image-receiving sheet used in the image forming method of the present invention, the coating amount of a coating solution per one layer constituting the multilayer in the range of 1g / m ² ~500g / m ² is preferred. The number of layers in the multilayer configuration can be arbitrarily selected as 2 or more. The receiving layer is preferably provided as the layer furthest away from the support.

Below, each process as one embodiment of the image forming method in the present invention will be described.
In the image forming method of the present invention, an image is formed by superimposing the receiving layer of the thermal transfer image-receiving sheet and the thermal transfer layer of the thermal transfer sheet so as to contact each other and applying thermal energy according to the image signal from the thermal head. can do. Specific image formation can be performed in the same manner as described in, for example, JP-A-2005-88545. In the image forming method of the present invention, the printing time is preferably less than 15 seconds, more preferably 3 to 12 seconds, and more preferably 3 to 7 seconds from the viewpoint of shortening the time required to provide the printed matter to the consumer. It is particularly preferred.

  In view of satisfying the above printing time, in the image forming method of the present invention, the line speed during printing needs to be 0.05 msec / line or more and 1.25 msec or less, preferably 0.8 msec / line or less, more preferably 0.75 msec / line or less. Furthermore, 0.65 msec or less is preferable. Further, from the viewpoint of improving transfer efficiency under high speed conditions, the maximum temperature reached by the thermal head during printing is preferably 180 ° C. or higher and 450 ° C. or lower, preferably 200 ° C. or higher and 450 ° C. or lower, more preferably 250 ° C. or higher and 450 ° C. or lower. It is. Furthermore, 350 degreeC or more and 450 degrees C or less are preferable.

The present invention can be used in printers, copiers and the like using a thermal transfer recording system. As the means for applying thermal energy at the time of thermal transfer, any conventionally known means for applying can be used. By controlling the time, the intended purpose can be sufficiently achieved by applying thermal energy of about 5 to 100 mJ / mm ² . The heat-sensitive transfer image-receiving sheet of the present invention can also be applied to various uses such as a sheet or roll-shaped heat-sensitive transfer image-receiving sheet capable of thermal transfer recording and cards by appropriately selecting a support.

  According to the image forming method of the present invention, as described above, it is possible to obtain a bright and smooth image close to a silver salt photograph without feeling the roughness of a digital image in which three colors are arranged with dots. . According to the image forming method of the present invention, the above-described excellent image quality can be achieved in a dry condition that does not require a developer or the like, and as described above, “higher image formation” and “higher thermal transfer temperature”. "Can also be suitably dealt with. As a result, an image with a particularly high magenta density can be formed without causing the user to wait for a long time, and high image robustness that maintains the vividness over a long period of time can be realized.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these. In Examples, “part” or “%” is based on mass unless otherwise specified.
Example 1

[Preparation of thermal transfer sheet]
(Preparation of thermal transfer sheet coating liquid and protective layer coating liquid)
The following coating solutions were prepared for preparing a thermal transfer sheet.
------------------------------------
Preparation of coating solution PY-1 for yellow thermal transfer layer -----------------------------------
Dye compound (Y2-6) 2.8 parts Dye compound (Y1 (see below)) 2.8 parts Polyvinyl acetoacetal resin 4.8 parts (ESREC BX-1, trade name, manufactured by Sekisui Chemical Co., Ltd.)
Release agent 0.06 parts (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Release agent 0.04 parts (TSF4701, trade name, Momentive Performance
(Materials Japan GK)
Matting agent 0.12 parts (Flusen UF, trade name, manufactured by Sumitomo Seika Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 2/1) 89 parts -----------------------------------

------------------------------------
Preparation of magenta thermal transfer layer coating liquid PM-1 -----------------------------------
3. Dye compound (M-1) 3.2 parts Dye compound (M2-2) 0.6 part Dye compound (M2-3) 1.8 parts Dye compound (C2-1) 0.4 part Polyvinyl acetoacetal resin 8 parts (S REC BX-1, trade name, manufactured by Sekisui Chemical Co., Ltd.)
Release agent 0.06 parts (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Release agent 0.04 parts (TSF4701, trade name, Momentive Performance
(Materials Japan GK)
Matting agent 0.12 parts (Flusen UF, trade name, manufactured by Sumitomo Seika Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 2/1) 89 parts -----------------------------------

------------------------------------
Preparation of Cyan Heat Transfer Layer Coating Liquid PC-1 ------------------------------------
Dye compound (C1-2) 1.3 parts Dye compound (C2-1) 4.5 parts Polyvinyl acetoacetal resin 4.8 parts (ESREC BX-1, trade name, manufactured by Sekisui Chemical Co., Ltd.)
Release agent 0.06 parts (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Release agent 0.04 parts (TSF4701, trade name, Momentive Performance
(Materials Japan GK)
Matting agent 0.12 parts Methyl ethyl ketone / toluene (mass ratio 2/1) 89 parts ------------------------------ -------

Production of release layer coating liquid PU1 for protective layer capable of thermal transfer Diacetylcellulose (L-30, trade name, Daicel Chemical) 6 parts Methyl ethyl ketone 94 parts

Preparation of release layer coating liquid PO1 for protective layer capable of thermal transfer 88 parts of acrylic resin solution (solid content 40%) (UNO-1, trade name, manufactured by Gifu Ceramic Co., Ltd.)
Methanol / isopropanol (mass ratio 1/1) 12 parts

Preparation of adhesive layer coating solution A1 for protective layer capable of thermal transfer Acrylic resin (Dianal BR-77, trade name, manufactured by Mitsubishi Rayon Co., Ltd.) 27 parts UV absorbent UV-1 1 part UV absorbent UV-2 2 parts UV absorbent UV-3 1 part UV absorbent UV-4 1 part PMMA fine particles (polymethyl methacrylate fine particles) 0.4 parts methyl ethyl ketone / toluene (mass ratio 2/1) 68 parts

(Preparation of thermal transfer sheet 101 by application of the coating solution)
A polyester film having a thickness of 6.0 μm (Lumirror, trade name, manufactured by Toray Industries, Inc.) was used as a support. A back layer (thickness 1 μm) was formed on the back side of the film. The thermal transfer sheet 101 in which the thermal transfer layer of yellow, magenta, and cyan (coating amount 1 g / m ² when dry film) and the protective layer are applied in the surface order on the surface side of the polyester film thus prepared. Was made. In addition, after apply | coating the protective layer release layer coating liquid PU1 for a protective layer, and drying, after apply | coating the protective layer peeling layer coating liquid PO1 on it and drying it, on it further The protective layer adhesive layer coating solution A1 was applied. The coating amount at the time of the dry film was a release layer of 0.1 g / m ² , a release layer of 0.5 g / m ² , and an adhesive layer of 1.5 g / m ² .

(Preparation of thermal transfer sheets 102-106)
A thermal transfer sheet 102 was obtained in the same manner as the thermal transfer sheet 101 except that the magenta thermal transfer layer coating liquid PM-1 in the thermal transfer sheet 101 was changed as follows.
------------------------------------
Magenta thermal transfer layer coating solution ------------------------------------
Dye compound (M2-2) 1.3 parts Dye compound (M2-3) 4.3 parts Dye compound (C2-1) 0.4 parts Polyvinylacetoacetal resin 4.8 parts (S-REC BX-1, trade name, Sekisui Chemical Co., Ltd.)
Release agent 0.06 parts (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Release agent 0.04 parts (TSF4701, trade name, Momentive Performance
(Materials Japan GK)
Matting agent 0.12 parts (Flusen UF, trade name, manufactured by Sumitomo Seika Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 2/1) 89 parts -----------------------------------

A thermal transfer sheet 103 was obtained in the same manner as the thermal transfer sheet 101 except that the magenta thermal transfer layer coating liquid PM-1 in the thermal transfer sheet 101 was changed as follows.
------------------------------------
Magenta thermal transfer layer coating solution ------------------------------------
Dye compound (M-1) 3.2 parts Dye compound (M2-2) 0.6 part Dye compound (M2-3) 1.8 parts Dye compound (C2-1) 0.4 part Polyvinyl butyral resin 4.8 (Denkabuchiral # 6000-C, trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.)
Release agent 0.06 parts (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Release agent 0.04 parts (TSF4701, trade name, Momentive Performance
(Materials Japan GK)
Matting agent 0.12 parts (Flusen UF, trade name, manufactured by Sumitomo Seika Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 2/1) 89 parts -----------------------------------

A thermal transfer sheet 104 was obtained in the same manner as the thermal transfer sheet 101 except that the magenta thermal transfer layer coating liquid PM-1 in the thermal transfer sheet 101 was changed as follows.
------------------------------------
Magenta thermal transfer layer coating solution ------------------------------------
Dye compound (M-1) 3.2 parts Dye compound (M2-2) 0.6 part Dye compound (M2-3) 1.8 parts Dye compound (C2-1) 0.4 part Polyester resin (the following composition) 4.8 parts Release agent 0.06 parts (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Release agent 0.04 parts (TSF4701, product name, manufactured by Momentive Performance Materials Japan GK)
Matting agent 0.12 parts (Flusen UF, trade name, manufactured by Sumitomo Seika Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 2/1) 89 parts Here, the polyester resin used in the coating solution is a polyester having a number average molecular weight of 1800 obtained by polymerizing the following acid component and diol component in the following molar ratio. is there.
Isophthalic acid 8 parts Terephthalic acid 42 parts Ethylene glycol 5 parts Diethylene glycol 45 parts ---------------------------- ----

A thermal transfer sheet 105 was obtained in the same manner as the thermal transfer sheet 101 except that the magenta thermal transfer layer coating liquid PM-1 in the thermal transfer sheet 101 was changed as follows.
------------------------------------
Magenta thermal transfer layer coating solution ------------------------------------
3. Dye compound (M-8) 3.2 parts Dye compound (M2-2) 0.6 part Dye compound (M2-3) 1.8 parts Dye compound (C2-1) 0.4 part Polyvinyl acetoacetal resin 8 parts (S REC BX-1, trade name, manufactured by Sekisui Chemical Co., Ltd.)
Release agent 0.06 parts (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Release agent 0.04 parts (TSF4701, product name, manufactured by Momentive Performance Materials Japan GK)
Matting agent 0.12 parts (Flusen UF, trade name, manufactured by Sumitomo Seika Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 2/1) 89 parts ZZZ

A thermal transfer sheet 106 was obtained in the same manner as the thermal transfer sheet 101 except that the magenta thermal transfer layer coating liquid PM-1 in the thermal transfer sheet 101 was changed as follows.
------------------------------------
Magenta thermal transfer layer coating solution ------------------------------------
3. Dye compound (M-1) 3.2 parts Dye compound (M2-2) 0.6 part Dye compound (M2-3) 1.8 parts Dye compound (C2-1) 0.4 part Polyvinyl acetoacetal resin 8 parts (ESREC KS-5, trade name, manufactured by Sekisui Chemical Co., Ltd.)
Release agent 0.06 parts (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Release agent 0.04 parts (TSF4701, trade name, Momentive Performance
(Materials Japan GK)
Matting agent 0.12 parts (Flusen UF, trade name, manufactured by Sumitomo Seika Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 2/1) 89 parts -----------------------------------

[Preparation of thermal transfer image-receiving sheet]
Preparation of Image Receiving Sheet S1 A gelatin subbing layer containing sodium dodecylbenzenesulfonate was provided after corona discharge treatment on the surface of a paper support laminated on both sides with polyethylene. On this, an undercoat layer, a heat insulating layer, a receiving layer lower layer, and a receiving layer upper layer having the following composition are laminated in this order from the support side in this order, and the 9th described in US Pat. No. 2,761,791 Multilayer coating was performed by the method illustrated in the figure. The coating amount at the time of drying is as follows: undercoat layer: 6.9 g / m ² , heat insulation layer: 9.0 g / m ² , receiving layer lower layer: 2.6 g / m ² , receiving layer upper layer: 2.7 g / m ² The coating was performed so that In this way, a heat-sensitive transfer image-receiving sheet was prepared in which the receiving layer was a layer formed with an aqueous coating solution.
Receptive layer upper layer Vinyl chloride latex (as solid content) 22.2 parts (Viniblanc 900, trade name, manufactured by Nissin Chemical Industry Co., Ltd.)
Vinyl chloride latex (as solids) 2.5 parts (Viniblanc 276, trade name, manufactured by Nissin Chemical Industry Co., Ltd.)
Gelatin 0.5 part Ester wax EW-1 2.0 part Surfactant F-1 0.06 part Receiving layer lower layer Vinyl chloride latex (as solid content) 24.3 parts (Viniblanc 690, trade name, (Nissin Chemical Industry Co., Ltd.)
Gelatin 1.5 parts Surfactant F-1 0.04 part Thermal insulation layer Hollow polymer particle latex (as solid content) 579 parts (MH5055, trade name, manufactured by Nippon Zeon Co., Ltd.)
Gelatin 279 parts Undercoat layer Polyvinyl alcohol 16.8 parts (Poval PVA205, trade name, manufactured by Kuraray Co., Ltd.)
150 parts of styrene butadiene rubber latex (as solid content) (SN-307, trade name, manufactured by Nippon A & L Co., Ltd.)
The following surfactant F-1 0.1 part

Preparation of image-receiving sheet S2 A synthetic paper (YUPO FPG200, thickness 200 μm, trade name, manufactured by YUPO Corporation) was used as a support, and this one surface was coated with a bar coater in the order of a white intermediate layer having the following composition and a receiving layer. went. The coating amount at the time of each drying was coated as a white intermediate layer 1.0 g / ^{m 2,} the receiving layer 4.0 g / ^{m 2,} drying each layer 110 ° C., it was carried out for 30 seconds. Thus, a heat-sensitive transfer image-receiving sheet for comparison, in which the receiving layer was a layer formed without using an aqueous coating solution, was prepared.
White intermediate layer Polyester resin (Byron 200, trade name, manufactured by Toyobo Co., Ltd.) 10 parts Fluorescent whitening agent (Uvitex OB, trade name, manufactured by Ciba Geigy) 1 part Titanium oxide 30 parts Methyl ethyl ketone / toluene (mass ratio 1 / 1) 90 parts Receiving layer 100 parts vinyl chloride-vinyl acetate resin (Solvine A, trade name, manufactured by Nissin Chemical Industry Co., Ltd.)
Amino-modified silicone 5 parts (Shin-Etsu Chemical Co., Ltd., trade name, X22-3050C)
Epoxy-modified silicone 5 parts (trade name, X22-3000E, manufactured by Shin-Etsu Chemical Co., Ltd.)
400 parts of methyl ethyl ketone / toluene (mass ratio 1/1)

[Image formation and evaluation test]
The heat-sensitive transfer sheets 101 to 106 and the heat-sensitive transfer image-receiving sheets S1 and S2 are transferred to a printer A (sublimation type thermal transfer printer ASK2000 (trade name) manufactured by Fuji Film Co., Ltd.) and a printer B (sublimation type thermal transfer printer ASK1500 (manufactured by Fuji Film Co., Ltd.)). Product name)) was processed so that it could be loaded and output in high-speed print mode. At this time, the line speed of the printer A was 0.73 msec / line, the maximum reached temperature of TPH was 410 ° C., the line speed of the printer B was 1.3 msec / line, and the maximum reached temperature of TPH was 280 ° C. . Note that the smaller the value, the faster the line speed.

Samples of each thermal transfer sheet and thermal transfer image-receiving sheet were used in combination as shown in Table 1, and the signal shown in (R, G, B) = (0, 0, 0) was printed by the printer shown in Table 1. Created an image. The reflection density of the obtained image was measured, and the value of the magenta density was listed in Table 1 as “Dm”. Furthermore, the abnormal transfer at that time was visually evaluated, and the results are also shown in Table 1.
Separately from the above, for the samples shown in Table 1, an image was output at a setting (setting of the heat generation amount of the thermal head) from which the gradation from the lowest magenta density (reflection density) to the highest magenta density was obtained. This sample was irradiated with xenon light (illuminance: 100,000 lux) through an ultraviolet cut filter and a heat ray cut filter having a light transmittance of 50% at 370 nm. This irradiation was continued for 12 days, and the residual rate after exposure for 12 days at an initial magenta concentration of 1.5 was calculated. The results are shown in the “light” section of “residual rate%” in Table 1.
Furthermore, a lattice pattern with a spacing of 3 pixels is printed on these samples with a line width of 3 pixels (both printers A and B have a resolution of 300 dpi in both the main scanning direction and the sub-scanning direction). It was allowed to stand for 1 day in an environment with a relative humidity of 85%. The sample before standing and the sample after standing were each measured with a concentration measuring device having an aperture diameter of 2 mm, and the residual concentration rate was calculated. The results are shown in the “Humidity” section of “Remaining rate%” in Table 1. Note that the density remaining rate exceeding 100% indicates an apparent increase in color over time, which is an undesirable phenomenon from the viewpoint of color image fastness as in the case of fading.
Residual rate (%) = [reflection density after aging / reflection density before aging] × 100 (%)

  From the results shown in Table 1, according to the image forming method of the present invention, high magenta density and high image quality can be maintained and the image fastness is excellent as the thermal transfer image forming speed is increased and the thermal head temperature is increased. It can be seen that a good image can be realized.

(Example 2)
The printer A described in Example 1 was changed to a printer C (CW-1 [trade name] manufactured by Citizen Co., Ltd.), and image formation and evaluation tests were performed in the same manner as in Example 1. The line speed of the printer C was 1.1 msec / line, and the maximum temperature reached by TPH was 280 ° C. The effect of the present invention was also obtained with printer C (the effect of the present invention was greater with printer A having a lower line speed).

It is a top view which shows typically the heat-sensitive transfer sheet (ink sheet) as one Embodiment used for the image forming method of this invention. FIG. 2 is a side view schematically showing a part of the thermal transfer sheet (ink sheet) of the embodiment shown in FIG. 1. It is a top view which shows typically the heat-sensitive transfer sheet (ink sheet) as another embodiment used for the image forming method of this invention.

Explanation of symbols

2 Base material (support)
3 Thermal transfer layer (dye layer)
4 Thermal transfer protective layer (laminate)
4a Release layer 4b Protective layer 4c Adhesive layer 5 Heat-resistant slip layer (back layer)
10,20 Thermal transfer sheet (ink sheet)

Claims (9)

A thermal transfer sheet having at least one yellow thermal transfer layer, a magenta thermal transfer layer, and a cyan thermal transfer layer, respectively, on the support, and at least one dye receiving layer on the support, the dye receiving layer being an aqueous system An image forming method for forming an image by superimposing a thermal transfer image-receiving sheet formed by coating using a coating liquid of
The magenta thermal transfer layer in the thermal transfer sheet contains at least one magenta dye represented by polyvinyl acetoacetal and the following general formula (M),
An image forming method, wherein a line speed during image formation is set to 0.05 msec / line or more and 1.25 msec / line or less.

(In General Formula (M), D ^{1 to} D ⁵ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, an acylamino group, a sulfonylamino group, a ureido group, An alkoxycarbonylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, or an amino group, each of D ⁶ and D ⁷ independently represents a hydrogen atom, an alkyl group, or an aryl group; D ⁶ and D ⁷ may be bonded to each other to form a ring, or D ³ and D ⁶ or / and D ⁵ and D ⁷ may be bonded to each other to form a ring. X, Y, and Z = C ^{(D 8)} -. represents a or a nitrogen atom wherein, ^{D 8} is hydrogen atom, an alkyl group, an aryl group, alkoxycarbonyl . Shi represents a group, an aryloxy group or an amino group, Further, X and Y are = C ^{(D 8)} - when, or Y and Z are = C ^{(D 8)} - when, two ^{D 8} together They may combine to form saturated or unsaturated carbocycles, each of which may further have a substituent.)   2. The image forming method according to claim 1, wherein the heat-sensitive transfer image-receiving sheet has at least one heat insulating layer containing a hollow polymer and a hydrophilic polymer between the receiving layer and the support.   3. The image forming method according to claim 1, wherein in the heat-sensitive transfer image-receiving sheet, at least one hydrophilic polymer contained in the heat insulating layer is gelatin.   The image forming method according to claim 1, wherein the heat-sensitive transfer image-receiving sheet is produced by aqueous simultaneous multilayer coating.   5. The image forming method according to claim 1, wherein a maximum temperature Tm of a thermal head of the printer during image formation is set to 180 ° C. or higher and 450 ° C. or lower during the image formation.   6. The image forming method according to claim 1, wherein a line speed during the image formation is set to 0.05 msec / line or more and 0.8 second / line or less. The image forming method according to claim 1, wherein the magenta dye contained in the magenta thermal transfer layer in the thermal transfer sheet is a compound represented by the following general formula (MB).

(In the general formula (MB), D ^{19 to} D ²³ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, an acylamino group, a sulfonylamino group, a ureido group, An alkoxycarbonylamino group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, or an amino group, and D ²⁴ and D ²⁵ each independently represent a hydrogen atom, an alkyl group, or an aryl group; D ²⁴ and D ²⁵ may be bonded to each other to form a ring, or D ²¹ and D ²⁴ or / and D ²³ and D ²⁵ may be bonded to each other to form a ring. ²⁶ is a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group or an amino group, You. May have each of these groups are further substituted.)   8. The image formation according to claim 1, wherein in the thermal transfer sheet, a yellow thermal transfer layer, a magenta thermal transfer layer, and a cyan thermal transfer layer are formed in a surface sequential manner on a support. Method.   The image forming method according to claim 1, wherein the heat-sensitive transfer sheet sheet further has a protective layer capable of thermal transfer.

Images