JP2005297304A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method in which an image forming layer has high mechanical strength, missing of an image can be prevented, and an image of abundant surface gloss can be attained. <P>SOLUTION: After image recording including white color and/or metallic gloss color on a transparent image receiving material having an image receiving layer is carried out on the image receiving layer, a transparent protective layer is transferred thereon. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming method. In particular, the present invention relates to an image forming method useful for producing a color proof (DDCP: direct digital color proof) in a printing field or a mask image by laser recording from a digital image signal.

  In the field of graphic arts, in general, a color proof is produced from a color separation film in order to check errors in the color separation process, necessity of color correction, etc. before the main printing (actual printing work). For color proofing, performance such as high resolution enabling high reproducibility of halftone images and high process stability are desired. In addition, in order to obtain a color proof similar to an actual printed material, it is preferable to use a base material used for the actual printed material or a pigment as a coloring material as a material used for the color proof. As a method for producing a color proof, there is a high demand for a dry method that does not use a developer.

  As a dry color proof production method, a recording system for producing a color proof directly from a digital signal has been developed along with the popularization of an electronic system in a pre-printing process (pre-press field). Such an electronic system is particularly intended to produce a high-quality color proof, and generally reproduces a dot image of 150 lines / inch or more. In order to record a high-quality proof from a digital signal, laser light that can be modulated by the digital signal and can narrow down the recording light is used as a recording head. For this reason, it is necessary to develop a recording material that exhibits high recording sensitivity with respect to laser light and exhibits high resolving power that enables reproduction of high-definition halftone dots.

  As a recording material used in a transfer image forming method using laser light, on a support, a light-to-heat conversion layer that absorbs laser light to generate heat, and a pigment is a component such as a heat-meltable wax or binder. A heat-melt transfer sheet having an image forming layer dispersed in this order (Patent Document 1), a photothermal conversion layer containing a photothermal conversion substance on a support, and a very thin layer (0.03 to 0.3 μm). An ablation type thermal transfer sheet in which a thermal release layer and an image forming layer containing a color material are provided in this order is disclosed (Patent Document 2).

These image forming methods can use printing paper provided with an image receiving layer (adhesive layer) as an image receiving sheet material, and can easily obtain multicolor images by transferring images of different colors onto the image receiving sheet one after another. In addition, it is useful for producing large-sized color proofs (DDCP: Direct Digital Color Proof) such as A2 and B2.
In the printing field, printing on a transparent support may be performed separately from color printing on white paper, which is mainly for packaging applications.
At this time, in order to hide the base of the transparent support or to prevent the opposite side of the transparent support from being seen through, the white base is once transferred onto the support, and yellow, magenta, cyan, Transfer of so-called process color using four colors of black, thermal transfer sheet containing white pigment in image forming layer is used for white background or metallic gloss color, and other color thermal transfer sheet formed on image receiving layer There is a need to use a thermal transfer type image forming material for transferring a multicolor image to a transfer sheet such as a transparent plastic film.
In addition, although patent document 3 does not describe a package application or the like, it is proposed to use a thermal transfer sheet of a special color such as white for DDCP.
Patent Document 4 proposes an image forming method that sequentially includes a step of transferring an image formed on an intermediate transfer image receiving sheet together with the image receiving layer onto a final image carrier, and a step of heat-treating the transferred image. The present invention provides an image forming method that can be used very well for proofreading applications such as commercial printing, and can also be used for proofreading for special high gloss printing samples and gravure printing.
On the other hand, as described above, the method of transferring a color image containing a white background or metallic gloss color on a support using a thermal transfer sheet on the image receiving sheet has a problem that the process is complicated.
Therefore, when a color image including the white background or metallic gloss color is formed on the image receiving sheet to form the final image holding member, there is a problem that the mechanical strength of the image forming layer is low and the image is dropped. .
In the packaging field as described above, there is a need for an image with a rich surface gloss, but no suitable means for achieving it has been found.

JP-A-5-58045 Japanese Patent Laid-Open No. 6-219052 JP 2002-86938 A JP 2003-285561 A

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, an object of the present invention is to provide an image forming method in which an image forming layer has high mechanical strength, can prevent image drop-out, and the like, and an image having a rich surface gloss can be obtained.

That is, the means for solving the above problems are as follows.
1) Image formation wherein image recording including white and / or metallic gloss color is performed on a transparent image-receiving material having an image-receiving layer on the image-receiving layer, and then a transparent protective layer is transferred thereon. Method.
2) Transfer of the protective layer is performed using a protective layer forming material in which at least one protective layer is formed on one side of a support, and the protective layer of the protective layer forming material is formed on the image receiving layer. The image forming method as described in 1) above, wherein the protective layer is transferred onto the image by superposition and heat and pressure treatment.
3) The image forming method described in 1) or 2) above, wherein smoothing treatment is performed after the protective layer is transferred.
4) The image forming method as described in 3) above, wherein the smoothing process is carried out by heating and pressurizing a separate press sheet.
5) The image forming material method according to 4) above, wherein the unevenness of the surface of the pressing sheet is Rz ≦ 4.0 μm.
6) Image formation according to any one of 2) to 5) above, wherein Rz of the surface on which the protective layer is formed of the support of the protective layer forming material is 4.0 μm or less. Method.
7) The image forming method as described in any one of 1) to 6) above, wherein image recording is performed by thermal transfer.

  Since the present invention does not transfer an image formed on an image receiving material to a support, it is an extremely simple and low-cost image forming method, and the formed image is also covered with a protective layer, and smoothing processing is performed. Therefore, it is possible to obtain a glossy image having high scratch strength and excellent blocking resistance. Further, the present invention can stably and easily perform an effective smoothing process by using an inexpensive jig such as a pressing sheet.

In the image forming method of the present invention, an image recording containing a white and / or metallic gloss color is performed on a transparent image-receiving material having an image-receiving layer, and then a transparent protective layer is transferred thereon. It is characterized by.
For the transfer of the protective layer, a protective layer forming material in which at least one protective layer is formed on one side of the support is used, and the protective layer of the protective layer forming material is superimposed on the image formed on the image receiving layer. The protective layer is preferably transferred onto the image by heating and pressing.
In the image forming method of the present invention, it is preferable to perform a smoothing process when or after transferring the protective layer.
In the present invention, one having a transparent protective layer transferred onto an image recorded on a transparent image-receiving material having an image-receiving layer is hereinafter also referred to as an image carrier. The smoothed image carrier is usually the final image carrier. In the present invention, this final image carrier is also referred to as a recorded image carrier.
In the present invention, the smoothing process means a process of applying heat and / or pressure to the surface of the image holding member including at least the surface of the protective layer.
The image receiving material is composed of a transparent material. The image receiving material may have a single layer structure or a multilayer structure. In the latter case, for example, a resin composition such as a cushion layer and an image receiving layer may be laminated on a support as described later. In the former case, the image receiving material may be composed only of a support.

The image recorded on the image receiving material may be single color or multicolor.
In the present invention, the image is preferably an image including a white or metallic gloss color. The white color means a white color obtained by using metal oxide particles or the like, but is not necessarily limited to metal oxide particles, and is not particularly limited as long as the same effect can be obtained. The metallic luster means gloss obtained using metal particles or the like, but is not necessarily limited to metal and is not particularly limited as long as the same effect is obtained.

The smoothing treatment in the present invention is preferably a heat and pressure treatment.
Here, the heating and pressurizing process means a process of applying pressure to the image holding body simultaneously with heating. The heating temperature is preferably 100 to 140 ° C, and more preferably 110 to 130 ° C. Moreover, as a heat-and-pressure processing apparatus, what uses a counter roll is preferable. Examples of the roll material include metal-metal, metal-plastic, plastic-plastic rubber, and plastic rubber-plastic rubber. The processing speed is usually 50 to 2000 mm / second, preferably 200 to 1000 mm / second. Moreover, a well-known thermal laminator, for example, “FL760T Extra” manufactured by Fuji Photo Film Co., Ltd. can be used.
The smoothing process preferably uses a pressing sheet. The pressing sheet is carried out so as to be in contact with at least one surface of the image receiving material having an image, preferably both surfaces thereof, and to be sandwiched by the heating and / or pressing means from the outside of the pressing sheet. Is preferred.
The pressure sheet is brought into contact with the protective layer forming material superimposed on at least one surface of the image receiving material having an image, preferably on both surfaces, and is pressed by heating and / or pressure means. It is preferable that the protective layer is transferred onto the image so as to be sandwiched from the outside of the film and smoothed.
Further, the smoothing treatment is preferably performed using the image receiving material and the pressure sheet in the same manner as described above after transferring the protective layer from the protective layer forming material onto the image.
The unevenness of the surface of the pressure sheet is preferably such that Rz is 4.0 μm or less, more preferably 0.8 μm or less, and further preferably 0.2 μm or less.
Further, the Rz of the surface on which the protective layer is formed of the support of the protective layer forming material is preferably 4.0 μm or less, more preferably 0.8 μm or less, and further preferably 0.2 μm or less.
The measurement of Rz is based on JIS82.
Examples of the material of the pressure sheet include the same materials as described in the explanation of the support for the image forming material described later. Further, it is preferable to select the Young's modulus, hardness, and the like of the pressure sheet according to various purposes (desired glossiness, etc.).
It is also preferable to perform the smoothing process while bringing a metal plate such as an aluminum plate into contact with the outside of the pressing sheet (the side where no image receiving material is present). The metal plate is preferably provided at least on the image receiving material side. The Rz of the aluminum plate is preferably about the same as the pressing sheet.
In the image forming method of the present invention, it is preferable that the surface gloss is increased by 5 to 100% as compared with the case where the smoothing treatment is not performed. Here, the thing which does not perform a smoothing process means the image holding body which is not subjected to a smoothing process. Surface gloss means glossiness according to JIS-K7105.

  In the image forming method of the present invention, the image recording on the image receiving material is preferably performed by thermal transfer, preferably laser thermal transfer.

  The recorded image holding member obtained by the image forming method of the present invention has high surface strength, excellent blocking resistance, and good gloss.

The image forming material used in the image forming method of the present invention comprises a transparent image receiving material having an image receiving layer, a transfer material including an image forming layer provided on a support, and a transparent protective layer on the support. An image forming material composed of a protective layer forming material, which is used to obtain the recorded image holding member of the present invention.
As the image forming material used in the present invention, it is particularly important to use a protective layer forming material. The transparent protective layer of the protective layer forming material (hereinafter also simply referred to as “protective layer”) preferably has an area that can cover at least the image on the image receiving material, and is several cm larger than the peripheral edge of the image. More preferably, it is an area.
The transfer material may be composed of one material or may be composed of two or more materials. The image forming layer has a specific color. Desired color images can be obtained by using transfer materials carrying image forming layers of various colors.
It is preferable that the transfer material includes at least one material having an image protective layer containing a white or metallic gloss color.
The transfer material is preferably a thermal transfer material, and more preferably a laser thermal transfer type material.

The image forming material used in the present invention can constitute a multicolor image forming material as described above. The multicolor image forming material of the present invention can be composed of at least two types of transfer materials (one is preferably white or metallic glossy color) having image forming layers having different colors from each other, an image receiving material, and a protective layer forming material. The transfer material having image forming layers having different colors from each other is preferably 4 or more, more preferably 5 or more. The colors of the image forming layers in the case of 4 types are yellow (Y) and magenta (M). , Cyan (C) and white (W), or metallic glossy color (S), and the color of the image forming layer in the case of 5 types is obtained by adding black (K) to the above. Examples of the metallic gloss color (S) include gold (Go) and silver (Si).
The transfer material may include other colors that cannot be expressed by a combination of process colors, such as green (G), orange (O), red (R), blue (B), and pink (P).

In the laser thermal transfer type multicolor image forming material of the present invention, in the photothermal conversion layer of at least one color thermal transfer material, the ratio of the absorbance A at 808 nm to the layer thickness X (μm) of the photothermal conversion layer is A / X = 2. It is preferable that the absorbance A is controlled to 5 to 3.2, preferably 2.7 to 3.0, and the absorbance A is set to 1.0 to 2.0, preferably 1.3 to 1.7.
By setting the ratio (A / X) of the absorbance A of the photothermal conversion layer to the thickness X (μm) of the photothermal conversion layer and the absorbance A within the specified range, coloring of the image forming layer due to the decomposition product of the photothermal conversion dye is minimized. It can be suppressed to the limit, the sensitivity at the time of recording is high, and the image quality can be made good.
Further, by setting A / X in the above range, it is possible to record an image in a large size such that the resolution of the transferred image is preferably 2400 dpi or more, more preferably 2600 dpi or more and 515 mm or more × 728 mm or more.
The absorbance A refers to the absorbance of the photothermal conversion layer at the peak wavelength of 808 nm of the laser beam used for recording, and can be measured using a known spectrophotometer. In the present invention, UV-spectrophotometer UV-240 manufactured by Shimadzu Corporation was used. The absorbance A is a value obtained by subtracting the value of the support alone from that including the support.

Since the thermal transfer image using the laser thermal transfer type multicolor image forming material of the present invention has a sharp dot shape, fine lines of fine characters can be reproduced well. The heat generated by the laser beam is transmitted to the transfer interface without diffusing in the surface direction, and the image forming layer is sharply broken at the interface between the heating part and the non-heating part. For this purpose, the photothermal conversion layer in the thermal transfer material is made thinner and the mechanical properties of the image forming layer are controlled.
In the simulation, it is estimated that the photothermal conversion layer instantaneously reaches about 700 ° C., and if the film is thin, it is likely to be deformed or broken. When deformation or destruction occurs, the photothermal conversion layer is transferred to the image receiving material together with the transfer layer, or the transfer image becomes non-uniform. On the other hand, in order to obtain a predetermined temperature, the photothermal conversion substance must be present in a high concentration in the film, and problems such as pigment precipitation and migration to an adjacent layer also occur.
For this reason, it is preferable to reduce the thickness of the photothermal conversion layer to about 0.5 μm or less by selecting an infrared absorbing dye having excellent photothermal conversion characteristics and a heat-resistant binder such as polyamide-imide or polyimide.

In general, when the photothermal conversion layer is deformed, or when the image forming layer itself is deformed by high heat, the image forming layer transferred to the image receiving layer has uneven thickness corresponding to the sub-scanning pattern of the laser beam, As a result, the image becomes non-uniform and the apparent transfer density decreases. This tendency is more conspicuous as the image forming layer is thinner. On the other hand, if the thickness of the image forming layer is large, the sharpness of the dots is impaired and the sensitivity is also lowered.
In order to achieve both of these conflicting performances, it is preferable to improve transfer unevenness by adding a low melting point material such as wax to the image forming layer. In addition, by adding inorganic fine particles in place of the binder, the layer thickness is appropriately increased so that the image forming layer breaks sharply at the interface between the heated part and non-heated part, maintaining the sharpness and sensitivity of the dots. In addition, the transfer unevenness can be improved.

In general, when the coating layer of the thermal transfer material absorbs moisture, the mechanical properties and thermal properties of the layer change, and the humidity dependence of the recording environment occurs.
In order to reduce the temperature / humidity dependency, it is preferable that the dye / binder system of the light-to-heat conversion layer and the binder system of the image forming layer be an organic solvent system.

  In order to prevent the hue from changing when the infrared absorbing dye moves from the photothermal conversion layer to the image forming layer due to high heat during printing, the infrared absorbing dye / It is preferable to design the photothermal conversion layer with a combination of binders.

The image receiving material and the thermal transfer material are preferably held on the drum by vacuum contact. This vacuum contact is important because an image is formed by controlling the adhesive force between both materials, and the image transfer behavior is very sensitive to the clearance between the image receiving layer surface of the image receiving material and the image forming layer surface of the transfer material. If the clearance between materials increases due to foreign matter such as dust, image defects and image transfer unevenness occur.
In order to prevent such image defects and image transfer unevenness, it is preferable to provide uniform clearance by providing uniform irregularities on the thermal transfer material or the image receiving material so as to improve air flow.

  As a method for forming the unevenness, there are generally post-treatment such as embossing treatment and addition of a matting agent to the coating layer, but the addition of the matting agent is preferable for simplifying the production process and stabilizing the material over time.

In order to reliably reproduce the sharp dots as described above, the recording apparatus side is also required to have a high-precision design. Specifically, known devices are used, but are not limited thereto. When a laser is used for image recording in the image forming method of the present invention, the apparatus used has the same basic configuration as that of a conventional laser thermal transfer recording apparatus. This configuration is a so-called heat mode outer drum recording system in which a recording head having a plurality of high-power lasers irradiates and records a laser onto a thermal transfer material and an image receiving material fixed on the drum. Among them, the following aspect is a preferable configuration. The supply of the image receiving material and the thermal transfer material is a fully automatic roll supply. If desired, the protective layer forming material can be supplied as a roll, and the protective layer can be transferred by a laser. After the laser transfer of the protective layer, a smoothing process such as a heating and pressing process can be performed.
The image receiving material, the thermal transfer material, or the protective layer forming material is fixed to the recording drum by vacuum suction. In this case, the protective layer forming material may be subjected to only a close contact process with the image receiving material by vacuum suction, the laminate is transferred from the drum to a smoothing apparatus, and the protective layer may be transferred simultaneously with the smoothing process. A large number of vacuum suction holes are formed on the recording drum, and the material is adsorbed to the drum by reducing the pressure inside the drum with a blower, a vacuum pump or the like. Since the thermal transfer material or the protective layer forming material is further adsorbed from above the image receiving material being adsorbed, the size of the thermal transfer material or the protective layer forming material is made larger than that of the image receiving material. Air between the thermal transfer material or the protective layer forming material and the image receiving material is sucked from the area of the thermal transfer material only outside the image receiving material.

Next, the outline of the mechanism of multicolor image formation by thin film thermal transfer using a laser will be described with reference to FIG.
An image forming laminate 30 in which the image receiving material 20 is laminated on the surface of the image forming layer 16 of the thermal transfer material 10 is prepared. The thermal transfer material 10 has a support 12, a light-to-heat conversion layer 14 thereon, and an image forming layer 16 thereon, and the image receiving material 20 has a support 22 and an image receiving layer 24 thereon. The image receiving layer 24 is laminated on the surface of the image forming layer 16 of the thermal transfer material 10 so as to be in contact therewith (FIG. 1A). When laser light is irradiated in a time-sequential manner in an image-like manner from the support 12 side of the thermal transfer material 10 of the laminate 30, the laser light irradiated region of the photothermal conversion layer 14 of the thermal transfer material 10 generates heat, and the image forming layer 16. The adhesive strength with the lowers (FIG. 1B). Thereafter, when the image receiving material 20 and the thermal transfer material 10 are peeled off, the laser light irradiated region 16 ′ of the image forming layer 16 is transferred onto the image receiving layer 24 of the image receiving material 20 (FIG. 1C).

  The type, intensity, beam diameter, power, scanning speed, and the like of the laser beam used for light irradiation are specifically those described in paragraph (0041) of JP-A-2002-337468, It is not limited to these.

  As a method for forming a multicolor image, as described above, a plurality of thermal transfer materials are used, and multiple image layers (image forming layers on which images are formed) are repeatedly superimposed on the same image receiving material. Form.

Thermal transfer recording using laser light irradiation is a method capable of forming an image on an image receiving material by converting the laser beam into heat and transferring the image forming layer containing the pigment to the image receiving material using the thermal energy. The state change of the pigment, dye, or image forming layer at the time of transfer includes any state of a solid state, a softened state, a liquid state, and a gas state, and is preferably a solid or softened state. Thermal transfer recording using laser light irradiation includes, for example, conventionally known melt transfer, transfer by ablation, sublimation transfer, and the like.
Among these, the above-mentioned thin film transfer type and melting / ablation type are preferable in that an image having a hue similar to printing is created.

The image created on the image receiving material can be post-exposed with light having an intensity in the ultraviolet region. The photoradical generator can erase the coloration of the infrared-absorbing dye or its decomposition product in the image forming layer. By performing the post-exposure treatment, it is possible to prevent the hue from being changed by subsequent indoor exposure.
As a light source for the post-exposure treatment, a light having a wavelength that is absorbed by the photo radical generator is preferable, and a fluorescent lamp, a black light, a metal halide lamp, or the like can be used.
The transfer of the protective layer using the protective layer forming material may be performed either before or after the post-exposure treatment.

  By connecting the above apparatuses on the plate making system, a system capable of exhibiting a function as a color proof is constructed. As a system, it is necessary to output from the recording apparatus a printed material having an image quality as close as possible to a printed material output from certain plate-making data. Therefore, software for bringing colors and halftone dots closer to the printed material is necessary. Specific system connections include those described in paragraph (0040) of Japanese Patent Laid-Open No. 2002-337468, but are not limited to these.

The thermal transfer material, the image receiving material, and the protective layer forming material that are preferably used in the recording apparatus of the above system will be described below.
[Thermal transfer material]
The thermal transfer material preferably has at least a light-to-heat conversion layer and an image forming layer on a support, and further has other layers as necessary.

(Support)
There is no particular limitation on the material of the support of the thermal transfer material, and various support materials can be used according to the purpose. Specifically, those described in paragraph (0051) of JP-A-2002-337468 are used, but not limited thereto.

  In order to improve the adhesiveness with the photothermal conversion layer provided on the support of the thermal transfer material, a surface activation treatment and / or one or more undercoat layers may be provided. Examples of the surface activation treatment include glow discharge treatment and corona discharge treatment. As a material for the undercoat layer, it is preferable that both surfaces of the support and the light-to-heat conversion layer exhibit high adhesion, have low thermal conductivity, and have excellent heat resistance. Examples of such a material for the undercoat layer include styrene, styrene-butadiene copolymer, gelatin and the like. The total thickness of the undercoat layer is usually 0.01 to 2 μm. In addition, various functional layers such as an antireflection layer and an antistatic layer can be provided on the surface of the thermal transfer material opposite to the side on which the photothermal conversion layer is provided, or surface treatment can be performed as necessary. Specifically, the back layer described in paragraph (0053) of JP-A-2002-337468 can be used, but is not limited thereto.

(Photothermal conversion layer)
The light-to-heat conversion layer contains a light-to-heat conversion substance, a binder, and a matting agent, and further contains other components as necessary.
The photothermal conversion substance is a substance having a function of converting irradiated light energy into heat energy. Generally, it is a dye (including a pigment, the same applies hereinafter) that can absorb laser light. When performing image recording with an infrared laser, it is preferable to use an infrared absorbing dye as the photothermal conversion substance. Examples of the dyes are black pigments such as carbon black, macrocyclic compound pigments having absorption in the visible to near infrared region such as phthalocyanine and naphthalocyanine, and laser absorbing materials for high-density laser recording such as optical disks. Examples include organic dyes (cyanine dyes such as indolenine dyes, anthraquinone dyes, azulene dyes, phthalocyanine dyes), and organometallic compound dyes such as dithiol nickel complexes. Among them, cyanine dyes exhibit a high extinction coefficient for light in the infrared region, so that when used as a photothermal conversion substance, the photothermal conversion layer can be made thin, and as a result, the recording sensitivity of the thermal transfer material can be reduced. Since it can improve more, it is preferable.
As the photothermal conversion substance, an inorganic material such as a particulate metal material such as blackened silver can be used in addition to the pigment.

  As the photothermal conversion substance used in the present invention, a compound represented by the following general formula (1) is preferable, and it has excellent heat resistance, and the absorbance does not decrease without decomposing even with the passage of time. preferable.

In the formula (1), examples of the ring completed by Z include a benzene ring, a naphthalene ring, a pyridine ring, a quinoline ring, a pyrazine ring, and a quinoxaline ring. Further, another substituent R ⁶ may be bonded onto Z. Examples of such substituent R ⁶ include an alkyl group, an aryl group, a heterocyclic residue, a halogen atom, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylcarbonyl group, an arylcarbonyl group, and an alkyloxycarbonyl group. , Aryloxycarbonyl group, alkylcarbonyloxy group, arylcarbonyloxy group, alkylamide group, arylamide group, alkylcarbamoyl group, arylcarbamoyl group, alkylamino group, arylamino group, carboxylic acid group, alkylsulfonyl group, arylsulfonyl And various substituents such as a group, an alkylsulfonamido group, an arylsulfonamido group, an alkylsulfamoyl group, an arylsulfamoyl group, a cyano group, and a nitro group. The number (p) of the substituents bonded on Z is usually preferably 0 or about 1 to 4. When p is 2 or more, the plurality of R ⁶ may be the same as or different from each other.

Among the substituents represented by R ⁶ , halogen atoms (eg, F, Cl, etc.), cyano groups, substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms (eg, methoxy group, ethoxy group, dodecyloxy) Group, methoxyethoxy group, etc.), substituted or unsubstituted phenoxy group having 6 to 20 carbon atoms (eg, phenoxy group, 3,5-dichlorophenoxy group, 2,4-di-t-pentylphenoxy group), Substituted or unsubstituted alkyl group having 1 to 20 carbon atoms (for example, methyl group, ethyl group, isobutyl group, t-pentyl group, octadecyl group, cyclohexyl group, etc.), substituted or unsubstituted group having 6 to 20 carbon atoms Phenyl groups (for example, phenyl group, 4-methylphenyl group, 4-trifluoromethylphenyl group, 3,5-dichlorophenyl group, etc.) are preferred. There.

In the general formula (1), T represents —O—, —S—, —Se—, —N (R ¹ ) —, —C (R ² ) (R ³ ) —, or —C (R ⁴ ). = C (R ⁵ )-. In this case, the group represented by R ¹ , R ² , R ³ , R ⁴ and R ⁵ is preferably a substituted or unsubstituted alkyl group, aryl group or alkenyl group, and particularly preferably an alkyl group. 1-30 are preferable and, as for the carbon atom number of group represented by R < ¹ > -R < ⁵ >, 1-20 are especially preferable.

Moreover, when these groups represented by R ^{1 to} R ⁵ further have a substituent, examples of the substituent include a sulfonic acid group, an alkylcarbonyloxy group, an alkylamide group, an alkylsulfonamide group, an alkoxycarbonyl group, An alkylamino group, alkylcarbamoyl group, alkylsulfamoyl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, alkyl group, aryl group, carboxyl group, halogen atom, cyano group and the like are preferable.

Among these substituents, halogen atoms (for example, F, Cl and the like), cyano groups, substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms (for example, methoxy group, ethoxy group, dodecyloxy group, methoxyethoxy group) Group), a substituted or unsubstituted phenoxy group having 6 to 20 carbon atoms (eg, phenoxy group, 3,5-di-chlorophenoxy group, 2,4-di-t-pentylphenoxy group), substituted or An unsubstituted alkyl group having 1 to 20 carbon atoms (for example, a methyl group, an ethyl group, an isobutyl group, a t-pentyl group, an octadecyl group, a cyclohexyl group, etc.) or a substituted or unsubstituted phenyl group having 6 to 20 carbon atoms Group (for example, phenyl group, 4-methylphenyl group, 4-methylphenyl group, 4-trifluoromethylphenyl group, 3,5-dichlorophenyl) Sulfonyl group) are particularly preferred. R ^{1 to} R ⁵ are most preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, and T is particularly preferably —C (CH ₃ ) ₂ —.

  L in the general formula (1) represents a trivalent linking group formed by connecting 5 or 7 methine groups by a conjugated double bond, and may be substituted. That is, L represents a pentamethine group, a heptamethine group or the like generated by connecting methine groups with a conjugated double bond, specifically, groups represented by the following (L-1) to (L-6): preferable.

  Among the above specific examples, a linking group forming tricarbocyanine exemplified as (L-2), (L-3), (L-4), (L-5) and (L-6) is particularly preferable. . In the above formulas (L-1) to (L-6), Y represents a hydrogen atom or a monovalent group. Examples of the monovalent group represented by Y include a lower alkyl group (such as a methyl group), a lower alkoxy group (such as a methoxy group), a substituted amino group (a dimethylamino group, a diphenylamino group, a methylphenylamino group, a morpholino group, Imidazolidine groups, ethoxycarbonylpiperazine groups, etc.), alkylcarbonyloxy groups (acetoxy groups, etc.), alkylthio groups (methylthio groups, etc.), diano groups, nitro groups, halogen atoms (Br, Cl, F, etc.) and the like are preferable.

Particularly preferred among the groups represented by Y are hydrogen atoms, and particularly preferred among R ₇ and R ₈ are each a hydrogen atom or a lower alkyl group (such as a methyl group). In the above (L-4) to (L-6), i is 1 or 2, and j is 0 or 1. M represents a divalent linking group, and preferably represents a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms. For example, an ethylene group, a propylene group, and a butylene group are mentioned.
In the general formula (1), examples of the cation represented by X ⁺ include a metal ion (Na ⁺ , K ⁺ ) and an ammonium ion (eg HN ⁺ (C ₂ H ₅ ) ₃ ). Ions) and pyridinium ions.

  Specific examples of the compound represented by the general formula (1) include the following compounds, but are not limited thereto.

The compound represented by the general formula (1) can usually be easily synthesized in the same manner as when a carbocyanine dye is synthesized. That is, a heterocyclic enamine is reacted with an acetal such as CH ₃ O—CH═CH—CH═CH—CH (OCH ₃ ) ₂ or a compound represented by PhN—CH— (CH—CH) —NHPh. Can be easily synthesized. Here, Ph represents a phenyl group. In addition, as for the method for synthesizing these compounds, the description in JP-A-5-116450 can be specifically referred to.

  If the decomposition temperature of the light-to-heat conversion substance is high and difficult to decompose, the decomposition temperature of the light-to-heat conversion substance is preferably 200 ° C. or more, preferably from 250 ° C. More preferably. When the decomposition temperature is lower than 200 ° C., the decomposition of the light-to-heat conversion substance may cause fogging of the decomposition product, which may deteriorate the image quality.

  As the binder contained in the photothermal conversion layer, a polyimide resin or a polyamideimide resin is preferable.

The polyamide-imide resin is not particularly limited as long as it is soluble in a solvent and functions as a binder, but at least has a strength capable of forming a layer on a support and has a high thermal conductivity. Resins are preferred.
Polyamideimide as a binder is a polyamideimide having a thermal decomposition temperature (TGA method (thermal mass spectrometry) at a rate of temperature increase of 10 ° C./min and a mass decrease of 5% in an air stream) of 400 ° C. or more. The thermal decomposition temperature is more preferably 500 ° C. or higher. Moreover, it is preferable that a polyamideimide has a glass transition temperature of 200-400 degreeC, and it is more preferable that it has a glass transition temperature of 250-350 degreeC. When the glass transition temperature is lower than 200 ° C., fog may occur in the formed image. When the glass transition temperature is higher than 400 ° C., the solubility of the resin may be reduced and the production efficiency may be reduced.
In addition, it is preferable that the heat resistance (for example, heat distortion temperature and thermal decomposition temperature) of the binder of the photothermal conversion layer is higher than materials used for other layers provided on the photothermal conversion layer.

  The polyamideimide preferably used is a polyamideimide represented by the following general formula (2).

  In the general formula (2), R represents a divalent linking group. Preferred specific examples of the divalent linking group are described below.

  Especially, the coupling group of (6), (7), (11), (14) is preferable.

  In addition, these divalent linking groups may be single or plural may be bonded.

  The number average molecular weight of the polyamideimide represented by the general formula (I) is measured by gel permeation chromatography and is preferably 3000 to 50000, more preferably 10000 to 25000, as a polystyrene equivalent value.

  As a binder for the photothermal conversion layer, a polyamide-imide resin and another resin may be used in combination. As the resin to be used in combination, for example, those described in paragraph (0062) of JP-A-2002-337468 are used, and a polyimide resin is preferable. The combined use ratio is preferably 5 to 50% by weight, and more preferably 10 to 30%.

  As the mat particles contained in the photothermal conversion layer, for example, those described in paragraph (0074) of JP-A-2002-337468 are preferable, and silica and silicone resin particles are particularly preferable.

  Silicone resin particles have a lower specific gravity than silica particles, and thus are more preferable because of high liquid stability. However, silicone resin particles have a broad particle size distribution compared to silica particles and often contain huge particles in which a plurality of matting agent particles are aggregated. If such agglomerates are present, image recording of this portion does not occur, and white-spotted defects may occur. For this reason, it is preferable to use a matting agent from which aggregates have been removed by classification treatment. As a method for classifying the matting agent, various methods can be appropriately employed as long as the particles can be classified. Examples thereof include classification using a sieve, a method using a dry air classifier, a method using a wet air classifier, and the like. Among them, the method using a dry air classifier is preferably employed because it is simpler and requires less drainage than the method using a wet air classifier, and has higher accuracy and efficiency than a sieve.

As a result, a matting agent comprising particles having an average particle diameter of 0.5 to 5 μm and having a major axis length of 15 μm or more or an aggregate content of 100 ppm or less is preferable. More preferably, the average particle diameter is in the range of 1.1 to 3 μm, and the content of particles or aggregates having a length in the major axis direction of 15 μm or more is 20 ppm or less. This average particle diameter can be determined, for example, by photographing the particles with a scanning electron microscope. The addition amount of the matting agent is preferably 0.1 to 100 mg / m ² .

By adding a vinylpyrrolidone copolymer to the photothermal conversion layer, the sensitivity of the thermal transfer material can be increased and the edge sharpness of the printed image can be improved.
The copolymer component having such a function of the vinyl pyrrolidone copolymer is not particularly limited as long as it is incompatible with polyimide resin or polyamide resin, but vinyl acetate, styrene, olefin, acrylic acid and methacrylic acid. Is particularly preferred. One or more of these components can be a copolymer component of a vinylpyrrolidone copolymer. In the vinylpyrrolidone copolymer, the molar ratio of the copolymerization component is preferably vinylpyrrolidone: copolymerization component = 50 or more and less than 100: greater than 0 and 50 or less, and more preferably 60 to 90:10 to 40.
The mass average molecular weight of the vinyl pyrrolidone polymer or vinyl pyrrolidone copolymer is preferably 2000 to 500000, more preferably 10000 to 250,000.

  Preferable examples of the vinyl pyrrolidone copolymer include a vinyl pyrrolidone / vinyl acetate copolymer, a vinyl pyrrolidone / styrene copolymer, a vinyl pyrrolidone / 1-butene copolymer, and a vinyl pyrrolidone / acrylic acid copolymer. .

  In the present invention, the vinyl pyrrolidone polymer and / or the vinyl pyrrolidone copolymer is contained in the photothermal conversion layer, but the mode of inclusion is not particularly limited and is arbitrary. In the photothermal conversion layer, the blending ratio of the main binder to the vinyl pyrrolidone polymer and / or the vinyl pyrrolidone copolymer is preferably 0.1 to 30% by mass, more preferably 1 to 10% by mass with respect to the main binder.

  If necessary, a surfactant, a thickener, an antistatic agent and the like may be further added to the photothermal conversion layer.

  The light-to-heat conversion layer is prepared by dissolving a light-to-heat conversion substance and a binder, preparing a coating solution to which a matting agent and other components are added, if necessary, and applying the solution onto a support and drying. be able to.

The photothermal conversion layer is preferably 0.03 to 1.0 [mu] m, and more preferably 0.2 to 0.7 [mu] m. Further, it is preferable that the photothermal conversion layer has an optical density of 1.0 to 2.0 with respect to light having a wavelength of 808 nm because transfer sensitivity of the image forming layer is improved. More preferably, it has an optical density of 1.3 to 1.8.
The ratio of absorbance / layer thickness (μm) is preferably 2.0 to 3.5, and more preferably 2.7 to 3.1. When it is lower than 2.0, the transfer speed is lowered, and when it is higher than 3.5, yellow coloring of the transferred image is increased.

(Image forming layer)
The image forming layer contains at least a pigment to be transferred to the image receiving material to form an image, and further contains a binder for forming the layer, a photo radical generator, and optionally other components.

The white pigment for the thermal transfer material W preferably has a particle size of 0.2 to 0.4 μm.
Usually, titanium oxide fine particles are subjected to a surface treatment for the purpose of improving dispersibility and improving weather resistance. In particular, with respect to the weather resistance, titanium oxide has photocatalytic properties, so it absorbs ultraviolet rays and erodes the coating layer. Therefore, the surface treatment is intended to wrap the surface of titanium oxide and suppress photocatalytic activity. As the type of surface treatment, the type and the coating amount can be selected from the following depending on the purpose. The inorganic treatment includes alumina treatment, silica / alumina treatment, titania treatment, zirconia treatment, and the like, and the organic treatment includes polyhydric alcohol treatment, amine treatment, silicon treatment, fatty acid treatment, and the like. Silica / alumina treatment is preferable in that high hiding power can be obtained.
In the present invention, it is preferable that the image forming layer contains titanium oxide (hereinafter also referred to as titanium oxide for the present invention) in which the particle surface is coated with alumina and silica.
The particle diameter of the titanium oxide for use in the present invention is obtained by measuring the coated particles, and is obtained by calculating the mass average particle diameter from the measurement data obtained by TEM.
The coating amount of alumina and silica of the titanium oxide is a ratio with respect to the coated titanium oxide, and is required to be 5% by mass or more in order to obtain a high concealment rate, but is 6 to 9% by mass. Is preferred. The titanium oxide is preferably a rutile type having a higher concealment rate.

In addition, since the titanium oxide for use in the present invention has a high concealment rate, the image forming layer of the white thermal transfer material has a reflection optical density (reflection) when the solid portion of the recorded image of the image forming layer is measured with a visual filter. The ratio (reflection OD / layer thickness) of the layer thickness (μm unit) of the image forming layer (OD) to 0.15 or more, more preferably 1.60 or more. This reflection OD is obtained by measuring a solid image recorded on a transparent transfer medium on a black backing, and is measured by, for example, X-rite 938. The smaller the reflection OD, the darker the white color, that is, the more difficult it is to see unnecessary colors through the image formed on the transfer object, and the higher the concealability that only the image by thermal transfer can be seen clearly. The OD is preferably about 0.35 or more.
Accordingly, the thickness of the image forming layer of the white thermal transfer material of the present invention is preferably 2.0 μm or less, and more preferably 1.5 μm or less. In the present invention, since the layer thickness can be made relatively thin, both the hiding power and the recording sensitivity can be ensured.
As the white pigment contained in the image forming layer of the white thermal transfer material, together with the titanium oxide for the present invention, it may be used in combination with calcium carbonate, calcium sulfate or the like as long as the effect of the present invention is maintained.

Examples of the metal for obtaining a metallic luster color used in the present invention include aluminum, gold, bronze, copper, zinc, iron, silver, lead, tin, titanium, and chromium, and aluminum is particularly preferable.
If the size of the metal particles is too small, the metal particles become dark and the metallic luster is lowered, and if the metal particles are thick, the image forming layer becomes thick, which is not preferable. The size and shape of the metal particles are preferably such that the particle thickness is 0.04 to 0.7 μm and the particle size is 2 to 30 μm, and the thickness is 0.05 to 0.1 μm and the particle size is 3 to 3 μm. The thing of 15 micrometers is preferable. Furthermore, the metal particles are preferably in the form of a flat plate having a thickness to length ratio of 1: 2 to 1: 2000, more preferably 1:20 to 1: 2000. : It is especially preferable that it is 500 flat form.

  Specific examples of the binder for the image forming layer include those described in paragraph (0085) of JP-A-2002-337468, but are not limited thereto.

The image forming layer may contain the following components (1) to (4) as the other components.
(1) Waxes As waxes, those described in paragraph (0087) of JP-A-2002-337468 are specifically used, but are not limited thereto.
(2) Plasticizer Specific examples of the plasticizer include those described in paragraph (0090) of JP-A-2002-337468, but are not limited thereto.
(3) Photoradical generator As the photoradical generator, known ones used for initiating photopolymerization and the like can be used, but the absorption peak is 300 to 500 nm, particularly 300 to 450 nm, and more preferably 300 to 400 nm. Organic compounds having odor are preferred in that they are less colored. Specifically, active halogen compounds, active ester compounds, organic peroxides, lophine dimers, aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, azinium salts, borate salts, ketals, There are aromatic ketones, diketones, thiols, azo compounds, acylphosphine oxide compounds, but acylphosphine oxide compounds such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2, 4,6-trimethylbenzoyldiphenylphosphine oxide and the like are preferable.
The addition amount of the photo radical generator is usually 0.01 to 10 mmol / m ² , preferably 0.1 to 1 mmol / m ² .
(4) Others In addition to the above components, the image forming layer further contains a surfactant, inorganic or organic fine particles (silica gel, etc.), oils (linseed oil, mineral oil, etc.), thickeners, antistatic agents, etc. You may contain.

  For the image forming layer, a coating solution in which a pigment and the binder or the like are dissolved or dispersed is prepared, and this is applied to the photothermal conversion layer (if the following thermal release layer is provided on the photothermal conversion layer) It can be provided by applying to and drying.

  On the light-to-heat conversion layer of the heat transfer material, gas is generated by the action of heat generated in the light-to-heat conversion layer, or adhering water is released, thereby the bonding strength between the light-to-heat conversion layer and the image forming layer. A heat-sensitive release layer containing a heat-sensitive material that weakens the heat resistance can be provided. Such heat-sensitive materials include compounds (polymers or low-molecular compounds) that themselves decompose or alter by heat to generate gases, and compounds that absorb or adsorb a considerable amount of easily vaporizable gases such as moisture (polymers). Alternatively, a low molecular compound) or the like can be used. These may be used in combination.

  Specific examples of the polymer that generates gas by being decomposed or altered by heat include those described in paragraph (0097) of JP-A-2002-337468, but are not limited thereto. Absent.

  When a low molecular weight compound is used as the heat sensitive material of the heat sensitive release layer, it is desirable to combine it with a binder. As the binder, there can be used a polymer which itself decomposes or denatures by heat to generate a gas, but a normal binder having no such property can also be used. The heat-sensitive peeling layer preferably covers the entire surface of the light-to-heat conversion layer, and its thickness is generally from 0.03 to 1 μm, preferably from 0.05 to 0.5 μm.

  In addition, instead of providing an independent heat-sensitive release layer in the thermal transfer material, the heat-sensitive material is added to the photothermal conversion layer coating solution to form a photothermal conversion layer, and serves as both the photothermal conversion layer and the heat-sensitive release layer. It can also be set as a simple structure.

Next, an image receiving material that can be used in combination with the thermal transfer material will be described.
[Image receiving material]
(Layer structure)
The image receiving material is usually provided with a support and one or more image receiving layers thereon, and if desired, any one of a cushion layer, a release layer and an intermediate layer between the support and the image receiving layer or It is the structure which provided two or more layers. In addition, it is preferable in terms of transportability to have a back layer on the surface of the support opposite to the image receiving layer.

(Support)
There is no restriction | limiting in particular as a support body, A normal sheet-like base material etc., such as a plastic, a metal, glass, resin coated paper, paper, and various composites, etc. are mentioned. Specifically, those described in paragraph (0102) of JP-A-2002-337468 are used, but are not limited thereto.

  The thickness of the support for the image receiving material is usually 10 to 400 μm, and preferably 25 to 200 μm. In addition, the surface of the support is subjected to surface treatment such as corona discharge treatment or glow discharge treatment in order to improve adhesion to the image receiving layer (or cushion layer) or adhesion to the image forming layer of the thermal transfer material. It may be.

(Image receiving layer)
In order to transfer and fix the image forming layer on the surface of the image receiving material, it is preferable to provide one or more image receiving layers on the support. Specifically, the image receiving layer described in paragraph (0106) of JP-A-2002-337468 is used, but is not limited thereto.

(Other layers)
A cushion layer may be provided between the support and the image receiving layer. When a cushion layer is provided, the adhesion between the image forming layer and the image receiving layer can be improved during laser thermal transfer, and the image quality can be improved. In addition, even when foreign matter is mixed between the thermal transfer material and the image receiving material during recording, the gap between the image receiving layer and the image forming layer is reduced due to the deformation action of the cushion layer, and as a result, the size of image defects such as white spots is reduced. You can also In addition, when an image is transferred and then transferred to a separately prepared printing paper or the like, the image receiving surface is deformed according to the uneven surface of the paper, so that the transfer property of the image receiving layer can be improved, and By reducing the gloss of an object, the closeness with a printed object can also be improved.

  Specifically, the cushion layer is described in paragraph (0112) of JP-A-2002-337468, but is not limited thereto.

The image receiving layer and the cushion layer need to be bonded until the stage of laser recording, but are preferably provided so as to be peelable in order to transfer the image onto the printing paper. In order to facilitate peeling, it is also preferable to provide a peeling layer with a thickness of about 0.1 to 2 μm between the cushion layer and the image receiving layer. If the layer thickness is too large, the performance of the cushion layer is difficult to appear, and therefore it is necessary to adjust it depending on the type of the release layer.
Specific examples of the release layer include those described in paragraph (0114) of JP-A-2002-337468, but are not limited thereto.

The image receiving material combined with the thermal transfer material may have a structure in which the image receiving layer also serves as a cushion layer. In this case, the image receiving material is a support / cushioning image receiving layer or a support / undercoat layer / cushioning property. The image receiving layer may be configured. Also in this case, it is preferable that the cushioning image-receiving layer is provided so as to be removable so that retransfer to the printing paper can be performed. In this case, the image after retransfer to the printing paper is an image having excellent gloss.
The thickness of the cushioning image-receiving layer is 5 to 100 μm, preferably 10 to 40 μm.

In addition, it is preferable to provide a back layer on the surface of the support opposite to the surface on which the image receiving layer is provided because the transportability of the image receiving material is improved. It is preferable to add an antistatic agent such as a surfactant or tin oxide fine particles, or a matting agent such as silicon oxide or PMMA particles to the back layer in order to improve transportability in the recording apparatus.
The additive may be added not only to the back layer but also to the image receiving layer and other layers as necessary. The type of the additive cannot be defined unconditionally depending on its purpose. For example, in the case of a matting agent, about 0.5 to 80% of particles having an average particle size of 0.5 to 10 μm can be added to the layer. The antistatic agent is appropriately selected from various surfactants and conductive agents so that the surface resistance of the layer is 10 ¹² Ω or less, more preferably 10 ⁹ Ω or less under the conditions of 23 ° C. and 50% RH. Can be used.

  Specific examples of the back layer include those described in paragraph (0119) of JP-A-2002-337468, but are not limited thereto.

[Protective layer forming material]
The protective layer forming material basically comprises a support and a protective layer. As the support, the same materials as the thermal transfer material and the image receiving material are used.
It is important that the protective layer is transparent, and the composition is preferably the same as or similar to that used for the image forming layer of the transfer material in order to ensure good adhesion, smoothness, and the like.
The thickness of the protective layer is preferably 0.5 to 10 μm, and more preferably 1 to 3 μm.

The thermal transfer material and the image receiving material can be used for image formation as a laminate in which an image forming layer of the thermal transfer material and an image receiving layer of the image receiving material are overlapped.
The laminate of the thermal transfer material and the image receiving material can be formed by various methods. For example, the image forming layer of the thermal transfer material and the image receiving layer of the image receiving material can be easily obtained by passing them through a pressure heating roller. In this case, the heating temperature is preferably 160 ° C. or lower, or 130 ° C. or lower.

  As another method for obtaining a laminate, the above-described vacuum contact method is also preferably used.

Examples of the present invention will be described below, but the present invention is not limited to these examples. Unless otherwise specified in the text, “part” means “part by mass”.
(Example 1)
-Production of thermal transfer material K (black)-
[Formation of back layer]
[Preparation of back first layer coating solution]
Acrylic resin aqueous dispersion 2 parts (Jurimer ET410, solid content 20% by mass, manufactured by Nippon Pure Chemical Co., Ltd.)
Antistatic agent (aqueous dispersion of tin oxide-antimony oxide) 7.0 parts (average particle size: 0.1 μm, 17% by mass)
Polyoxyethylene phenyl ether 0.1 part Melamine compound 0.3 part (Sumitic Resin M-3, manufactured by Sumitomo Chemical Co., Ltd.)
Distilled water 90.6 parts [Formation of back first layer]
One side (back side) of a biaxially stretched polyethylene terephthalate support (thickness Ra is 0.01 μm) with a thickness of 75 μm is subjected to corona treatment, and the dry first layer coating solution has a dry layer thickness of 0.03 μm. After coating, the film was dried at 180 ° C. for 30 seconds to form a back first layer.
[Preparation of back second layer coating solution]
3.0 parts of polyolefin (Chemical S-120, 27% by mass, manufactured by Mitsui Petrochemical Co., Ltd.)
Antistatic agent (tin oxide-antimony oxide aqueous dispersion) 2.0 parts (average particle size: 0.1 μm, 17% by mass)
Colloidal silica 2.0 parts (Snowtex C, 20% by mass, manufactured by Nissan Chemical Co., Ltd.)
Epoxy compound 0.3 part (Dinacol EX-614B, manufactured by Nagase Kasei Co., Ltd.)
92.7 parts of distilled water [Formation of back second layer]
A back second layer coating solution was applied onto the back first layer so that the dry layer thickness was 0.03 μm, and then dried at 170 ° C. for 30 seconds to form a back second layer.

<Formation of photothermal conversion layer>
[Preparation of coating solution for photothermal conversion layer]
The following components were mixed while stirring with a stirrer to prepare a photothermal conversion layer coating solution.
[Coating solution composition for photothermal conversion layer]
・ Infrared absorbing dye having the following structure: 0.5 part

・ 9 parts of polyamideimide resin (15% N-methylpyrrolidone solution)
("Viromax HR-11N", manufactured by Toyobo Co., Ltd.)
・ 0.06 parts of 1.5 μm silicone particles
("Tospar 120", manufactured by Toshiba Silicon Corporation)
-51 parts of N-methylpyrrolidone-34 parts of methyl ethyl ketone-5 parts of methanol-0.01 part of a fluorosurfactant (30% methyl ethyl ketone solution) ("Megafac F-780F", manufactured by Dainippon Ink & Chemicals, Inc.)

(Formation of photothermal conversion layer on support surface)
On one surface of a 75 μm-thick polyethylene terephthalate film (support), after applying the photothermal conversion layer coating solution using a wire bar, the coating is dried in an oven at 120 ° C. for 2 minutes, A photothermal conversion layer was formed on the support. When the optical density of the obtained photothermal conversion layer at a wavelength of 808 nm was measured with a UV-spectrophotometer UV-240 manufactured by Shimadzu Corporation, OD = 1.03. When the cross section of the photothermal conversion layer was observed with a scanning electron microscope, the layer thickness was 0.3 μm on average.

[Formation of image forming layer]
[Preparation of coating solution for black image forming layer]
Each of the following components was put into a kneader mill, a shearing force was applied while adding a small amount of solvent, and a dispersion pretreatment was performed. A solvent was further added to the dispersion to prepare a composition having the following composition, and sand mill dispersion was performed for 2 hours to obtain a pigment dispersion mother liquor.
[Black pigment dispersion mother liquor composition]
Composition 1
・ 12.6 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
-Pigment Black 7 4.5 parts ("Mitsubishi Carbon Black # 5", manufactured by Mitsubishi Chemical Corporation, PVC blackness: 1)
・ Dispersing aid 0.8 parts ("Solsperse S-20000", manufactured by ICI Corporation)
N-propyl alcohol 79.4 parts composition 2
・ 12.6 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
Pigment Black 7 10.5 parts (“Mitsubishi Carbon Black MA100”, manufactured by Mitsubishi Chemical Corporation, PVC blackness: 10)
・ Dispersing aid 0.8 parts ("Solsperse S-20000", manufactured by ICI Corporation)
・ 79.4 parts of n-propyl alcohol

Next, the following components were mixed while stirring with a stirrer to prepare a black image forming layer coating solution.
[Coating solution composition for black image forming layer]
-Black pigment dispersion mother liquor 185.7 parts Composition 1: Composition 2 = 70: 30 (parts)
・ 11.9 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
Wax-based compound (stearic acid amide “Neutron 2”, manufactured by Nippon Seika Co., Ltd.) 1.7 parts (behenic acid amide “Diamid BM”, manufactured by Nippon Kasei Co., Ltd.) 1.7 parts (lauric acid) Amide “Diamid Y” manufactured by Nippon Kasei Co., Ltd.) 1.7 parts (palmitic acid amide “Diamid KP” manufactured by Nippon Kasei Co., Ltd.) 1.7 parts (Erucaic acid amide “Diamid L-200”) , Nippon Kasei Co., Ltd.) 1.7 parts (Oleamide "Diamid O-200", Nippon Kasei Co., Ltd.) 1.7 parts, Rosin 11.4 parts ("KE-311", Arakawa Chemical) (Made by Co., Ltd.)
・ Fluorine-based surfactant (30% methyl ethyl ketone solution) 2.1 parts (“Megafac F-780F”, manufactured by Dainippon Ink & Chemicals, Inc.)
-Colloidal silica (30% methyl ethyl ketone dispersion) 7.1 parts ("MEK-ST", manufactured by Nissan Chemical Co., Ltd.)
・ 1050 parts of n-propyl alcohol ・ 295 parts of methyl ethyl ketone

[Formation of black image forming layer on photothermal conversion layer surface]
After applying the black image forming layer coating liquid on the surface of the light-to-heat conversion layer for 1 minute using a wire bar, the coating is dried in an oven at 100 ° C. for 2 minutes to form a black on the light-to-heat conversion layer. An image forming layer was formed. The thickness of the image forming layer of the obtained thermal transfer material Y was 0.60 μm.
Through the above steps, the photothermal conversion layer and the black image forming layer are provided on the support in this order in the order of the thermal transfer material (hereinafter referred to as the thermal transfer material K. Similarly, the yellow image forming layer is provided. Thermal transfer material Y, thermal transfer material M provided with a magenta image forming layer, thermal transfer material C provided with a cyan image forming layer, thermal transfer material W provided with a white image forming layer, metallic gloss color image A material provided with a formation layer was referred to as a thermal transfer material S).

-Production of thermal transfer material Y-
In the production of the thermal transfer material K, a thermal transfer material Y was produced in the same manner as in the production of the thermal transfer material K, except that a yellow image forming layer coating liquid having the following composition was used instead of the black image forming layer coating liquid. did. The thickness of the image forming layer of the obtained thermal transfer material Y was 0.42 μm.
[Yellow pigment dispersed mother liquor composition]
Yellow pigment composition 1:
・ 7.1 parts of polyvinyl butyral (“S-Lec B BL-1SH”, manufactured by Sekisui Chemical Co., Ltd.)
-Pigment Yellow 180 12.9 parts ("Novo Palm Yellow P-HG", manufactured by Clariant Japan Co., Ltd.)
・ Dispersing aid 0.6 parts ("Solsperse S-20000", manufactured by ICI Corporation)
-79.4 parts of n-propyl alcohol [yellow pigment dispersion mother liquor composition]
Yellow pigment composition 2:
・ 7.1 parts of polyvinyl butyral (“S-Lec B BL-1SH”, manufactured by Sekisui Chemical Co., Ltd.)
-Pigment Yellow 139) 12.9 parts ("Novo Palm Yellow M2R 70", manufactured by Clariant Japan Co., Ltd.)
・ Dispersing aid 0.6 parts ("Solsperse S-20000", manufactured by ICI Corporation)
・ 79.4 parts of n-propyl alcohol

[Coating solution composition for yellow image forming layer]
・ Yellow pigment dispersion mother liquor 126 parts Yellow pigment composition 1: Yellow pigment composition 2 = 95: 5 (parts)
・ 4.6 parts of polyvinyl butyral (“ESREC B BL-1SH”, manufactured by Sekisui Chemical Co., Ltd.)
-Wax compound (stearic acid amide "Nutron 2", manufactured by Nippon Seika Co., Ltd.) 0.7 part (behenamide "Diamid BM", manufactured by Nippon Kasei Chemical Co., Ltd.) 0.7 part (Laurin 0.7 parts (palmic acid amide “Diamid KP”, manufactured by Nippon Kasei Co., Ltd.) 0.7 parts (erucic acid amide “Diamid L-200”) "Nippon Kasei Co., Ltd." 0.7 parts (Oleamide "Diamid O-200", Nippon Kasei Co., Ltd.) 0.7 parts Nonionic surfactant 0.4 parts ("Chemist 1100 "Sanyo Kasei Co., Ltd. product)
・ Rosin 2.4 parts ("KE-311", manufactured by Arakawa Chemical Co., Ltd.)
・ Fluorosurfactant (30% methyl ethyl ketone solution) 0.8 parts (“Megafac F-780F”, manufactured by Dainippon Ink & Chemicals, Inc.)
・ 793 parts of n-propyl alcohol ・ 198 parts of methyl ethyl ketone

-Production of thermal transfer material M-
In the production of the thermal transfer material K, the thermal transfer material M was produced in the same manner as the production of the thermal transfer material K, except that a magenta image forming layer coating solution having the following composition was used instead of the black image forming layer coating solution. did. The thickness of the image forming layer of the obtained thermal transfer material M was 0.38 μm.
[Magenta pigment dispersion mother liquor composition]
Magenta pigment composition 1;
Polyvinyl butyral 12.6 parts (“Denka butyral # 2000-L”, manufactured by Denki Kagaku Kogyo Co., Ltd.)
Pigment Red 57: 1 15.0 parts ("Shimra Brilliant Carmine 6B-229", manufactured by Dainippon Ink & Chemicals, Inc.)
・ Dispersing aid 0.6 parts ("Solsperse S-20000", manufactured by ICI Corporation)
N-propyl alcohol 80.4 parts [magenta pigment dispersion mother liquor composition]
Magenta pigment composition 2;
Polyvinyl butyral 12.6 parts (“Denka butyral # 2000-L”, manufactured by Denki Kagaku Kogyo Co., Ltd.)
Pigment Red 57: 1 15.0 parts ("Lionol Red 6B-4290G", manufactured by Toyo Ink Co., Ltd.)
・ Dispersing aid 0.6 parts ("Solsperse S-20000", manufactured by ICI Corporation)
・ 79.4 parts of n-propyl alcohol

[Coating solution composition for magenta image forming layer]
-Magenta pigment dispersion mother liquor 163 parts Magenta pigment composition 1: magenta pigment composition 2 = 95: 5 (part)
・ 4.0 parts of polyvinyl butyral (“Denka Butyral # 2000-L”, manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ Wax compound (stearic acid amide “Nutron 2”, manufactured by Nippon Seika Co., Ltd.) 1.0 part (behenic acid amide “Diamid BM”, manufactured by Nippon Kasei Co., Ltd.) 1.0 part (lauric acid) Amide “Diamid Y”, manufactured by Nippon Kasei Co., Ltd. 1.0 part (palmitic acid amide “Diamid KP”, manufactured by Nippon Kasei Co., Ltd.) 1.0 part (erucic amide “Diamid L-200”) , Nippon Kasei Co., Ltd.) 1.0 part (Oleamide "Diamid O-200", Nippon Kasei Co., Ltd.) 1.0 part Nonionic surfactant 0.7 part ("Chemist 1100") Sanyo Chemical Co., Ltd.)
-4.6 parts of rosin ("KE-311", manufactured by Arakawa Chemical Co., Ltd.)
・ Pentaerythritol tetraacrylate 2.5 parts ("NK ester A-TMMT", manufactured by Shin-Nakamura Chemical Co., Ltd.)
-Fluorosurfactant (30% methyl ethyl ketone solution) 1.3 parts ("Megafac F-780F" manufactured by Dainippon Ink & Chemicals, Inc.)
・ N-propyl alcohol 848 parts ・ methyl ethyl ketone 246 parts

-Production of thermal transfer material C-
In the production of the thermal transfer material K, a thermal transfer material C was produced in the same manner as the production of the thermal transfer material K except that a cyan image forming layer coating solution having the following composition was used instead of the black image forming layer coating solution. did. The thickness of the image forming layer of the obtained thermal transfer material C was 0.45 μm.
[Cyan pigment dispersion mother liquor composition]
Cyan pigment composition 1:
・ 12.6 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
Pigment Blue 15: 4) 15.0 parts (“Cyanine Blue 700-10FG”, manufactured by Toyo Ink Co., Ltd.)
・ Dispersing aid 0.8 parts ("PW-36", manufactured by Enomoto Kasei Co., Ltd.)
110 parts of n-propyl alcohol [cyan pigment dispersion mother liquor composition]
Cyan pigment composition 2:
・ 12.6 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
-Pigment Blue 15 5.0 parts ("Lionol Blue 7027", manufactured by Toyo Ink Manufacturing Co., Ltd.)
・ Dispersing aid 0.8 parts ("PW-36", manufactured by Enomoto Kasei Co., Ltd.)
・ 110 parts of n-propyl alcohol

[Coating solution composition for cyan image forming layer]
-Cyan pigment dispersion mother liquor 118 parts Cyan pigment composition 1: Cyan pigment composition 2 = 90:10 (parts)
・ 5.2 parts of polyvinyl butyral (“ESREC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
・ Inorganic pigment “MEK-ST” 1.3 parts ・ Wax compound (stearic acid amide “Nutron 2”, manufactured by Nippon Seika Co., Ltd.) 1.0 part (behenic acid amide “Diamid BM”, Nippon Kasei Chemical 1.0 part (lauric acid amide “Diamid Y”, manufactured by Nippon Kasei Co., Ltd.) 1.0 part (palmitic acid amide “Diamid KP”, manufactured by Nippon Kasei Co., Ltd.) 1.0 Part (erucic acid amide “Diamid L-200” (manufactured by Nippon Kasei Co., Ltd.) 1.0 part (oleic acid amide “Diamid O-200”, manufactured by Nippon Kasei Co., Ltd.) 1.0 part / rosin 2 .8 parts ("KE-311", manufactured by Arakawa Chemical Co., Ltd.)
-1.7 parts of pentaerythritol tetraacrylate ("NK ester A-TMMT", manufactured by Shin-Nakamura Chemical Co., Ltd.)
-Fluorosurfactant (30% methyl ethyl ketone solution) 1.7 parts ("Megafac F-780F", manufactured by Dainippon Ink & Chemicals, Inc.)
・ N-propyl alcohol 890 parts ・ methyl ethyl ketone 247 parts

-Production of thermal transfer material W-
In the production of the thermal transfer material K, the thermal transfer material W was produced in the same manner as in the production of the thermal transfer material K, except that the white image forming layer coating liquid having the following composition was used instead of the black image forming layer coating liquid. did. The thickness of the image forming layer of the obtained thermal transfer material W was 1.5 μm.
[White pigment dispersion mother liquor composition]
・ 6.3 parts of polyvinyl butyral (“S-Lec B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
・ Titanium dioxide particles 28.0 parts ("JR805", manufactured by Teika)
・ Dispersing aid 1.5 parts ("Solsper 20000", manufactured by ICI Corporation)
・ N-propyl alcohol 65 parts

[Coating solution composition for white image forming layer]
-26 parts of the above white pigment dispersion mother liquor-Wax compound (Stearic acid amide "Nutron 2", manufactured by Nippon Seika Co., Ltd.) 0.1 part (Behenic acid amide "Diamid BM", manufactured by Nippon Kasei Co., Ltd. ) 0.1 part (lauric acid amide “Diamid Y”, manufactured by Nippon Kasei Co., Ltd.) 0.1 part (palmitic acid amide “Diamid KP”, manufactured by Nippon Kasei Co., Ltd.) 0.1 part (erucic acid) Amide "Diamid L-200" (Nippon Kasei Co., Ltd.) 0.1 part (Oleic acid amide "Diamid O-200", Nippon Kasei Co., Ltd.) 0.1 part Rosin 1.7 parts ( “KE-311”, manufactured by Arakawa Chemical Co., Ltd.)
-Fluorosurfactant (30% methyl ethyl ketone solution) 0.3 parts ("Megafac F-780F", manufactured by Dainippon Ink & Chemicals, Inc.)
・ Fluorescent whitening agent: 0.03 part of benzoxazole derivative (“Uvitex-OB” manufactured by Ciba-Geigy)
・ 54 parts of n-propyl alcohol ・ 17 parts of methyl ethyl ketone

-Production of thermal transfer material S-
In the production of the thermal transfer material K, the thermal transfer material S was prepared in the same manner as in the production of the thermal transfer material K, except that the metal glossy color image forming layer coating solution having the following composition was used instead of the black image forming layer coating solution. Was made. The thickness of the image forming layer of the obtained thermal transfer material S was 1.0 μm.

[Coating liquid composition for metallic glossy image forming layer]
・ 3.2 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
・ Aluminum paste (60%) 4.2 parts ("AM1501", manufactured by Asahi Kasei Corporation)
・ Fatty acid amide (20% solution) 4.1 parts (“PFA230”, manufactured by Kashiwagi Kasei Co., Ltd.)
Wax compound (stearic acid amide “Nutron 2”, manufactured by Nippon Seika Co., Ltd.) 0.2 part (behenic acid amide “Diamid BM”, manufactured by Nippon Kasei Co., Ltd.) 0.2 part (lauric acid) Amide “Diamid Y” manufactured by Nippon Kasei Co., Ltd.) 0.2 parts (palmitic acid amide “Diamid KP” manufactured by Nippon Kasei Co., Ltd.) 0.2 parts (Erucaic acid amide “Diamid L-200”) (Nippon Kasei Co., Ltd.) 0.2 parts (Oleamide "Diamid O-200", Nippon Kasei Co., Ltd.) 0.2 parts Rosin ester 0.7 parts ("KE-311", Arakawa) (Chemical Co., Ltd.)
-Fluorosurfactant (30% methyl ethyl ketone solution) 0.3 parts ("Megafac F-780F", manufactured by Dainippon Ink & Chemicals, Inc.)
・ N-propyl alcohol 67 parts ・ methyl ethyl ketone 20 parts

-Production of image receiving material-
A cushioning layer coating solution and an image receiving layer coating solution having the following composition were prepared.
1) Cushion layer coating solution / vinyl chloride-vinyl acetate copolymer 20 parts ("MPR-TSL", manufactured by Nissin Chemical Co., Ltd.)
Polyester plasticizer 10 parts ("Paraplex G-40", CP.HALL.COMPANY made)
・ 0.5 parts of fluorosurfactant ("Megafac F-177", manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 60 parts ・ Toluene 10 parts ・ N, N-dimethylformamide 3 parts

2) 5.8 parts of coating solution for image-receiving layer, polyvinyl butyral (“S-REC B BL-1”, manufactured by Sekisui Chemical Co., Ltd.)
-Styrene maleic acid copolymer half ester 3.1 parts ("ESREC B BL-1", manufactured by Sekisui Chemical Co., Ltd.)
・ Antistatic agent 0.16 parts ("Chemist 3033", manufactured by Sanyo Chemical Industries, Ltd.)
-Fluorosurfactant (30% methyl ethyl ketone solution) 0.08 parts ("Megafac F-780F", manufactured by Dainippon Ink & Chemicals, Inc.)
・ N-propyl alcohol 13 parts ・ methanol 46 parts ・ 1-methoxy-2-propanol 31 parts

  Using a narrow coater, the cushion layer-forming coating solution was applied onto a 50 μm thick transparent PET support, the coating layer was dried, and then the image-receiving layer coating solution was applied and dried. The coating amount was adjusted so that the thickness of the cushion layer after drying was about 10 μm and the thickness of the image receiving layer was about 3 μm.

-Production of protective layer forming material-
A protective layer coating solution having the following composition was prepared.
・ 10 parts of polyvinyl butyral (“S-REC BM-5”, manufactured by Sekisui Chemical Co., Ltd.)
・ 0.5 parts of PMMA particles with an average particle size of 5μ (“MX500”, manufactured by Soken Chemical Co., Ltd.)
-Fluorosurfactant (30% methyl ethyl ketone solution) 0.08 parts ("Megafac F-780F", manufactured by Dainippon Ink & Chemicals, Inc.)
・ N-propanol 40 parts ・ methanol 40 parts

Using a narrow coater, the above protective layer-forming coating solution is applied onto a PET support having a thickness of 50 μm and Rz = 0.8 μm, the coating layer is dried, and the layer thickness after drying is about 2 μm. The coating amount was adjusted so that
Rz was measured with Surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd.
The measurement conditions were a measurement speed of 0.06 mm / sec and a cutoff wavelength of 0.8 mm (JIS 82).

-Formation of transfer image-
A Luxel FINALPROOF 5600 was used as a recording apparatus, and a transfer image of the thermal transfer material W was obtained on the image receiving material. The image resolution is 2600 dpi.
When the laser recording-completed laminate is removed from the drum and the thermal transfer material W is manually peeled off from the image receiving material, only the light irradiation region of the image forming layer of the thermal transfer material W is transferred from the thermal transfer material W to the image receiving material. Has been confirmed.

  In the same manner as described above, four color images were transferred from the thermal transfer materials Y, thermal transfer material M, thermal transfer material C, and thermal transfer material K onto the image receiving material having the W image.

-Transfer of protective layer-
A protective layer forming material was overlaid on the image receiving material on which an image was formed so that the protective layer was in contact therewith. Further, both sides of the sheet are covered with a cover sheet (Rz is 0.15 μm, an easy-slip processed polyester sheet having a static frictional engagement with the image receiving sheet of 0.27), and the lower side has a thickness of 1 mm. The aluminum plates were stacked and processed with a laminator “FL760T Extra” manufactured by Fuji Film Co., Ltd., and only the PET base was peeled off from the protective layer forming material to form a protective layer on the image receiving material on which an image was formed. The glossiness of the obtained image was 99 (60 °). (See FIG. 2).

Example 2
In Example 1, a protective layer forming material was prepared as follows.
The same coating solution for forming a protective layer as in Example 1 was similarly formed on a release paper “Glasin Sepa 70GS8” (Rz = 7 μm) manufactured by Oji Paper Co., Ltd.
A protective layer was formed on the image-receiving material on which an image was formed by heating and pressurizing with a laminator, and then the following smoothing treatment was performed. The thickness of the protective layer was 2 μm.

-Smoothing process-
The both sides of the image-receiving material on which the protective layer is formed are sandwiched between pressing sheets (Rz = 0.8 μm, surface-treated polyester sheet having a coefficient of static friction with the image-receiving material of 0.27), and further An aluminum plate having a thickness of 1 mm was stacked on the lower side and treated with a laminator “FL760T Extra” manufactured by Fuji Film (see FIG. 3).
The glossiness (60 °) of the image area was changed from 60 to 100 by the smoothing process.
A high-quality color image including white color could be formed on the transparent support.

Example 3
Example 2 is the same as Example 2 except that no smoothing process is performed.
The glossiness of the image was 60 (60 °).
Example 4
In Example 1, the order of image transfer of the thermal transfer material was set to the order of K, C, M, Y, W in the color of the image forming layer.
In Example 1, the transfer material S was used in place of the transfer material W.
Comparative Example 1
In Example 1, no protective layer was provided.
The performance of the (recorded) image carrier obtained as described above was evaluated as follows.

-Evaluation method and evaluation results-
1. Scratch strength of image The image after rubbed 10 times with high quality paper was observed.
In Examples 1 to 5, there was no change in the image (◯), but in the comparative example, the image dropped out (×).
2. Anti-blocking The back surface and the front surface were overlapped, and a pressure of 1 kg per A4 was applied and left in an environment of 40 ° C. for 3 days.
In Examples 1 to 5, there was no change in the image (◯), but in the comparative example, the image dropped out (×).
3. Glossiness of image The glossiness of the formed image was visually evaluated.
Glossiness increases in the order of ×, Δ, and ○. The overall evaluation is also excellent in the order of x, Δ, and ○.

  Each example was commented in the result column of Table 1. In addition, although Example 2 performs the smoothing process separately, Examples 1, 4 and 5 perform the transfer of the protective layer and the smoothing process at the same time.

It is a figure explaining the outline of the mechanism of the image formation by the thin film thermal transfer using a laser. It is a figure which shows the positional relationship of the image forming material, cover sheet, and aluminum plate which are used for this invention before and after the transfer of a protective layer. It is a figure which shows the positional relationship of the image forming material, cover sheet, and aluminum plate which are used for this invention in the smooth process of a protective layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Thermal transfer material 12 Support body 14 Photothermal conversion layer 16 Image formation layer 16 'Laser light irradiated area 20 Image receiving material 22 Image receiving material support body 24 Image receiving layer 30 Laminated body

Claims (7)

  A method of forming an image, comprising: recording an image containing a white and / or metallic luster color on a transparent image-receiving material having an image-receiving layer on the image-receiving layer, and then transferring a transparent protective layer thereon.   For the transfer of the protective layer, a protective layer forming material in which at least one protective layer is formed on one side of the support is used, and the protective layer of the protective layer forming material is superimposed on the image formed on the image receiving layer. The image forming method according to claim 1, wherein the protective layer is transferred onto the image by heat and pressure treatment.   3. The image forming method according to claim 1, wherein a smoothing process is performed after the protective layer is transferred.   The image forming method according to claim 3, wherein the smoothing process is performed by heating and pressurizing a separate press sheet.   The image forming material method according to claim 4, wherein the unevenness of the surface of the pressing sheet is Rz ≦ 4.0 μm.   6. The image forming method according to claim 2, wherein Rz of the surface on which the protective layer is formed of the support of the protective layer forming material is 4.0 [mu] m or less.   The image forming method according to claim 1, wherein image recording is performed by thermal transfer.

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