JP2003291544A - Multi-color image forming material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-color image forming material excellent in the hues of a transfer image formed on an image receiving sheet and picture quality, and stable in transfer density. <P>SOLUTION: In the multi-color image forming material, the image receiving sheet having at least a image receiving layer on a support and the heat transfer sheet having at least a photothermal conversion layer and the image forming layer on the support is used to superpose the image forming layer of the heat transfer sheet and the image receiving layer of the image receiving sheet by facing each other, to irradiate them with a laser beam and transferring the region of the image forming layer irradiated with the laser beam to the image receiving layer of the image receiving sheet to record images. The difference in the reflection spectrum in a visible light range between the image forming layer before the image recorded by irradiation with the laser beam and the image forming layer when the image is transferred to the image receiving layer of the image receiving sheet by irradiation with the laser beam is not greater than 10%, or the color difference between the hues not exposed when the image forming layer transferred to the image receiving layer immediately after the image recording and those after exposure is within 2. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor image forming material for forming a high resolution full color image with a good hue by using a laser beam. In particular, the present invention relates to a multicolor image forming material 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.

[0002]

2. Description of the Related Art In the field of graphic arts, printing plates are printed using a set of color separation films made from color originals using lith films, but in general, this printing (actual printing work) In order to check errors in the color separation process and the need for color correction, the color proof is made from the color separation film. Color proofs are required to have high resolution that enables high reproducibility of halftone images and high process stability. Further, in order to obtain a color proof similar to an actual printed matter, a material used for the actual printed matter is used as the material used for the color proof, for example, a printing paper is used as the base material and a pigment is used as the coloring material. It is preferable. Also,
As a method for producing a color proof, there is a strong demand for a dry method that does not use a developing solution.

As a dry color proof manufacturing method, a recording system for directly manufacturing a color proof from a digital signal has been developed with the spread of an electronic system in a pre-printing step (prepress field). The purpose of such an electronic system is to produce a high-quality color proof, and generally reproduces a halftone dot image of 150 lines / inch or more. In order to record a high-quality proof from a digital signal, a laser beam that can be modulated by the digital signal and that can narrow down the recording light is used as a recording head. Therefore, it is necessary to develop a recording material that exhibits high recording sensitivity to laser light and high resolution capable of reproducing high-definition halftone dots.

As a recording material used in a transfer image forming method using a laser beam, a photothermal conversion layer which absorbs a laser beam to generate heat, a wax having a heat-melting pigment, a binder and the like are used as a recording material. A heat-melt transfer sheet having an image-forming layer dispersed in the above-mentioned components in this order (Japanese Patent Laid-Open No. Hei 5-
58045) is known. In the image forming method using these recording materials, the image forming layer corresponding to the region is melted by the heat generated in the laser light irradiation region of the photothermal conversion layer, and transferred onto the image receiving sheet laminated on the transfer sheet. A transfer image is formed on the image receiving sheet.

Further, in Japanese Unexamined Patent Publication No. 6-219052, a photothermal conversion layer containing a photothermal conversion substance, a very thin layer (0.03 to 0.3 μm) of a heat release layer, and a coloring material are provided on a support. A thermal transfer sheet in which an image forming layer containing the same is provided in this order is disclosed. In this thermal transfer sheet, the binding force between the image forming layer and the photothermal conversion layer, which are bound by the interposition of the thermal release layer, is reduced by being irradiated with laser light, and the thermal transfer sheet is laminated on the thermal transfer sheet. A high-definition image is formed on the image receiving sheet. The image forming method using the thermal transfer sheet utilizes so-called "ablation". Specifically, in a region irradiated with laser light, the thermal peeling layer partially decomposes and vaporizes, so that region The phenomenon in which the bonding force between the image forming layer and the photothermal conversion layer is weakened and the image forming layer in that region is transferred to the image receiving sheet laminated thereon is used.

In these image forming methods, it is possible to use a printing main paper provided with an image receiving layer (adhesive layer) as the image receiving sheet material, and to transfer a multicolor image by successively transferring images of different colors onto the image receiving sheet. An image forming method utilizing ablation has an advantage that a high-definition image can be easily obtained, and color proof (DDCP: direct digital color proof), Alternatively, it is useful for producing a high-definition mask image.

In order to shorten the recording time when irradiating an image with a laser beam to record an image, a multi-beam laser beam using a plurality of laser beams has been used in recent years. When recording is performed with a multi-beam laser beam using a conventional thermal transfer sheet, the image density of the transferred image formed on the image receiving sheet may be insufficient. In particular, the decrease in image density becomes remarkable when laser recording is performed with high energy. As a result of the study by the present inventors, it was found that the decrease in image density was caused by the transfer unevenness caused when laser irradiation was performed with high energy. Further, when an image is recorded by irradiating a laser beam, the photothermal conversion substance or its decomposition product contained in the photothermal conversion layer migrates to the image forming layer, and they are transferred together with the image forming layer. There is a problem that the hue of the transfer image formed is deteriorated.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in the prior art and achieve the following objects. That is, the object of the present invention is 1) that the thermal transfer sheet is not affected by the illumination light source even when compared with the pigment color material and the printed matter, and that the transfer of the color material thin film is excellent in halftone dot sharpness and stability 2). The image receiving sheet should be able to stably and reliably receive the image forming layer of the laser energy transfer film, 3) art (coated) paper, matte paper, lightly coated paper, etc. 64-157 g
A multicolor image that can be transferred to the actual paper corresponding to the range of / m ² and can reproduce delicate texture and accurate white paper (high key part), and 4) obtain extremely stable transfer peelability. To provide a forming material. Above all,
Due to the multi-beam laser light, the hue of the transferred image formed on the image receiving sheet is good, and the image quality is good, even when laser recording is performed at high energy.
Another object is to provide a multicolor image forming material having a stable transfer density.

[0009]

That is, the present invention provides the following multicolor image forming materials in order to achieve the above object. (1) Using an image receiving sheet having at least an image receiving layer on a support, and four or more types of thermal transfer sheets containing yellow, magenta, cyan, and black having at least a photothermal conversion layer and an image forming layer on the support , The image forming layer of each thermal transfer sheet and the image receiving layer of the image receiving sheet are superposed facing each other, irradiated with laser light, and the laser light irradiation region of the image forming layer is transferred onto the image receiving layer of the image receiving sheet to record an image. Which is a multicolor image forming material, the reflection spectrum of the image forming layer of the thermal transfer sheet before being irradiated with the laser beam and image recording is performed, and the image formation transferred onto the image receiving layer of the image receiving sheet by the irradiation of the laser beam. A multicolor image-forming material, wherein the difference in the visible light region from the reflection spectrum of the layer is 10% or less for each image-forming layer of each thermal transfer sheet. (2) Using an image-receiving sheet having at least an image-receiving layer on a support, and four or more types of thermal transfer sheets including yellow, magenta, cyan, and black having at least a photothermal conversion layer and an image-forming layer on the support , The image forming layer of each thermal transfer sheet and the image receiving layer of the image receiving sheet are superposed facing each other, irradiated with laser light, and the laser light irradiation region of the image forming layer is transferred onto the image receiving layer of the image receiving sheet to record an image. Which is a multicolor image forming material, the color difference between the hue of the image forming layer transferred to the image receiving layer of the image receiving sheet by the irradiation of the laser light immediately after image recording and the hue after the light exposure is not changed. A multicolor image forming material, wherein the number of image forming layers of each thermal transfer sheet is within 2. (3) The light source wavelength of the laser light is 750 to 850n
The multicolor image-forming material as described in (1) or (2) above, wherein m is m. (4) In each of the thermal transfer sheets, the SP value of the resin of the binder of the light-heat conversion layer, which is derived by the Okitsu method, is 25 or more, and the multicolor according to any one of (1) to (3) above. Image forming material. (5) The multicolor image-forming material as described in any of (1) to (4) above, wherein in each of the thermal transfer sheets, the binder resin of the photothermal conversion layer has an imide bond. (6) In each of the thermal transfer sheets, the photothermal conversion substance of the photothermal conversion layer is a cyanine dye, and the multicolor image-forming material as described in any one of (1) to (5) above. (7) The multicolor image-forming material as described in (5) above, wherein the cyanine dye has a structure represented by the following general formula (A).

[0010]

[Chemical 2]

(In the general formula (A), Z represents an atomic group for forming a benzene ring, a naphthalene ring or a heteroaromatic ring, and T represents -O-, -S-, -Se-, -N ( R ¹ )-,
^{-C (R 2) (R 3} ) -, or ^{-C (R 4) = C (} R 5) -
Represents R ¹ , R ² and R ³ each independently represent a hydrogen atom, an alkyl group, an alkenyl group or an aryl group, and R ⁴ and R ⁵ are each independently a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkoxy group. Group, aryloxy group,
It represents a carboxyl group, an acyl group, an acylamino group, a carbamoyl group, a sulfamoyl group, or a sulfonamide group. L represents a trivalent linking group formed by linking 5 or 7 methine groups by a conjugated double bond, M represents a divalent linking group, and X ⁺ represents a cation. (8) The multicolor image forming material as described in any one of (1) to (7) above, wherein the scanning speed of the laser light on each of the thermal transfer sheets is 8 m / sec or more. (9) When the image is recorded by irradiating the laser beam, the energy applied to the photothermal conversion layer of each thermal transfer sheet is 300 mJ / m ² or less, (1) to (8) above. The multicolor image-forming material as described in any one of 1.

The multicolor image-forming material of the present invention can achieve the above-mentioned object, and is the reflectance of the surface of the image-forming layer before image recording and the image-transferred image-receiving layer. The difference in reflectance in the visible light region from the reflectance of the image forming layer is 10
% Or less, or the color difference between the hue of the image forming layer transferred onto the image receiving layer immediately after image recording when not exposed and the hue after exposure is within 2 By configuring the light-heat conversion layer, the image forming layer, etc., the hue of the transfer image formed on the image receiving sheet becomes good, the image quality is good, and the transfer density is stable. can get.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Recent CTP (Computer To Plat)
e) In the era, film proofing becomes necessary and contract proofs that replace proofs and analog color proofs are needed. In order to obtain customer approval, color reproducibility that is consistent with printed matter and analog color proofs is required.According to these various requirements, the applicant uses the same pigment-based coloring material as the printing ink. , Has developed a DDCP system that can be transferred to real paper and has no moire. The target of this DDCP system is a large size (A2 / B2) digital direct color proof system which is capable of actual paper transfer, uses the same pigment-based coloring material as the printing ink, and has a high print similarity. The present invention can be suitably used for the DDCP system developed by the present applicant.

In the present invention, as described above, the reflection spectrum of the image forming layer of the thermal transfer sheet before the image recording is performed by the laser light irradiation and the image transferred onto the image receiving layer of the image receiving sheet by the laser light irradiation. The difference between the reflection spectrum of the forming layer and the reflection spectrum in the visible light region is 10% or less, or the image forming layer transferred onto the image receiving layer of the image receiving sheet by irradiation of laser light is not exposed immediately after image recording. The color difference between the hue at that time and the hue after exposure is
The thermal transfer sheet is configured so that the number of image forming layers of each thermal transfer sheet is within 2. The method for constructing the thermal transfer sheet having such characteristics is not particularly limited, but specifically, the binder of the photothermal conversion layer of the thermal transfer sheet, the photothermal conversion substance is selected and adjusted from those described below, or Examples of the method include using a colorless dye or a dye decomposition product, or bleaching a dye or a dye decomposition product.

The entire system developed by the applicant, including the contents of the present invention, will be described below. The present invention realizes a thermal transfer image with sharp halftone dots, and transfers the actual paper and a recording size of B2 or more (515 mm × 728).
mm or more (however, B2 size is 543 mm x 765 m
m) is preferable, and a size of 594 mm × 841 mm or more is more preferable). This thermal transfer image can be a halftone dot image with a resolution of 2400 dpi or higher (further, 2600 dpi or higher) according to the number of printed lines. Since each halftone dot has almost no bleeding or chipping and its shape is extremely sharp, it is possible to clearly form halftone dots in a high range from highlight to shadow. As a result, imagesetter and CTP
It is possible to output high-quality halftone dots with the same resolution as the setter, and it is possible to reproduce halftone dots and gradations with good printed matter approximation.

Further, in this thermal transfer image, since the halftone dot shape is sharp, halftone dots corresponding to the laser beam can be faithfully reproduced, and the environmental temperature / humidity dependency of recording characteristics is very small, so that a wide range of temperature / humidity environments can be obtained. It is possible to obtain stable reproducibility in both hue and density below. This thermal transfer image is formed using the coloring pigment used in the printing ink, and also has good repeatability and high accuracy.
CMS (color management system) can be realized. In addition, this thermal transfer image can be made to match the hue of Japan color, SWOP color, etc., that is, the hue of the printed matter, and the appearance of the color when the light source such as a fluorescent lamp or an incandescent lamp changes is similar to that of the printed matter. Change can be shown.

Further, since the dot shape of this thermal transfer image is sharp, fine lines of fine characters can be clearly reproduced.
The heat generated by the laser light is transmitted to the transfer interface without being diffused in the surface direction, and the image forming layer is sharply broken at the interface of the heated portion / non-heated portion. Therefore, the photothermal conversion layer in the thermal transfer sheet is made thin and the mechanical properties of the image forming layer are controlled. By the way, 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 / destruction occurs, the light-heat conversion layer is transferred to the image-receiving sheet together with the transfer layer, or the transferred image becomes non-uniform, which causes actual damage. 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, which causes problems such as deposition of dye and migration to an adjacent layer. Therefore, it is preferable to thin the light-heat conversion layer to about 0.5 μm or less by selecting an infrared absorbing dye having excellent light-heat conversion characteristics and a heat-resistant binder such as polyimide.

In general, when the photothermal conversion layer is deformed or the image forming layer itself is deformed due to high heat, the image forming layer transferred to the image receiving layer is uneven in thickness corresponding to the sub-scanning pattern of laser light. Occurs, resulting in non-uniform images and a decrease in apparent transfer density. This tendency is more remarkable as the thickness of the image forming layer is smaller. On the other hand, when the thickness of the image forming layer is large, the sharpness of dots is impaired and the sensitivity is also lowered. In order to achieve both of these contradictory performances, it is preferable to improve the transfer unevenness by adding a low melting point substance such as wax to the image forming layer. Also, by adding inorganic fine particles instead of the binder, the layer thickness can be appropriately increased so that the image forming layer is sharply broken at the interface between the heated portion and the non-heated portion, and the sharpness and sensitivity of the dots are maintained. Meanwhile, the transfer unevenness can be improved.

Generally, low melting point substances such as wax are
There is a tendency to seep out or crystallize on the surface of the image forming layer,
Problems may occur in the image quality and the temporal stability of the thermal transfer sheet. In order to deal with this problem, it is preferable to use a low melting point substance having a small SP value difference with the polymer of the image forming layer to improve the compatibility with the polymer and to separate the low melting point substance from the image forming layer. Can be prevented. It is also preferable to mix several kinds of low melting point substances having different structures to cause eutectic and prevent crystallization. As a result, an image having a sharp dot shape and less unevenness can be obtained.
Further, generally, when the coating layer of the thermal transfer sheet absorbs moisture, the mechanical properties and thermophysical properties of the layer change, and the humidity dependency of the recording environment occurs. In order to reduce this temperature / humidity dependency, it is preferable that the dye / binder system of the photothermal conversion layer and the binder system of the image forming layer are organic solvent systems. Further, it is preferable to select polyvinyl butyral as the binder of the image receiving layer and to introduce a polymer hydrophobizing technique in order to reduce its water absorption. Examples of the polymer hydrophobizing technique include reacting a hydroxyl group with a hydrophobic group as described in JP-A-8-238858, and crosslinking two or more hydroxyl groups with a hardener.

Further, usually, the image forming layer is also heated to about 500 ° C. or more during printing by laser exposure, and some of the pigments used in the past are thermally decomposed. This can be prevented by adopting it in the image forming layer. And due to the high heat during printing,
When the infrared absorbing dye migrates from the photothermal conversion layer to the image forming layer, in order to prevent the hue from changing, the photothermal conversion layer is combined with a strong holding infrared absorbing dye / binder as described above. It is preferable to design. Generally, high-speed printing causes energy shortage, and a gap corresponding to the laser sub-scanning interval is generated. As described above, increasing the dye concentration in the photothermal conversion layer and thinning the photothermal conversion layer / image forming layer can increase the efficiency of heat generation / transfer. Further, a low melting point substance is preferably added to the image forming layer for the purpose of increasing the effect of filling the gap by slightly flowing the image forming layer during heating and improving the adhesiveness to the image receiving layer. Further, in order to increase the adhesiveness between the image receiving layer and the image forming layer and to provide the transferred image with sufficient strength, it is preferable to use, for example, the same polyvinyl butyral as the image forming layer as the binder of the image receiving layer.

The image receiving sheet and the thermal transfer sheet are preferably held on the drum by vacuum contact. This vacuum contact is important because the image transfer behavior is very sensitive to the clearance between the image receiving layer surface of the image receiving sheet and the image forming layer surface of the transfer sheet because an image is formed by controlling the adhesive force of both sheets. If the clearance between the materials is widened due to foreign matter such as dust, image defects and image transfer unevenness will occur. In order to prevent such image defects and image transfer unevenness, it is preferable that the thermal transfer sheet is provided with uniform unevenness so that the air can flow smoothly and uniform clearance can be obtained.

As a method for making unevenness on the thermal transfer sheet, there are generally post-treatments such as embossing and addition of a matting agent to the coating layer, but addition of a matting agent is preferred for simplifying the manufacturing process and stabilizing the material with time. . The matting agent needs to be thicker than the coating layer thickness, and when the matting agent is added to the image forming layer, the image in the portion where the matting agent is present may be lost. It is preferably added to the conversion layer, whereby the image forming layer itself has a substantially uniform thickness, and an image free of defects can be obtained on the image receiving sheet.

In order to reliably reproduce the sharp dots as described above, the recording device side is also required to have a highly accurate design. The basic configuration is the same as that of the conventional laser thermal transfer recording device. This structure is a so-called heat mode outer drum recording system in which a recording head equipped with a plurality of high-power lasers irradiates a thermal transfer sheet and an image receiving sheet fixed on the drum with laser for recording. Among them, the following aspects are preferable configurations. The image receiving sheet and the thermal transfer sheet are supplied by fully automatic roll supply. The image receiving sheet and the thermal transfer sheet are fixed to the recording drum by vacuum suction. A large number of vacuum suction holes are formed on the recording drum, and the inside of the drum is depressurized by a blower or a depressurizing pump so that the sheet is adsorbed on the drum.
Since the thermal transfer sheet is further adsorbed on the image receiving sheet, the size of the thermal transfer sheet is made larger than that of the image receiving sheet. The air between the thermal transfer sheet and the image receiving sheet, which has the largest effect on the recording performance, is sucked from the area outside the image receiving sheet, which is only the thermal transfer sheet.

In this apparatus, it is assumed that a large number of sheets of B2 size can be stacked and stacked on the discharge table. Therefore, a method is adopted in which air is ejected between the two sheets to lift the sheet discharged later. A configuration example of this device is shown in FIG. The sequence of the present apparatus as described above will be described. 1) The sub-scanning axis of the recording head 2 of the recording apparatus 1 is returned to the origin by the sub-scanning rail 3, the main-scanning rotation axis of the recording drum 4 and the thermal transfer sheet loading unit 5. 2) The image receiving sheet roll 6 is unwound by the conveying roller 7, and the leading edge of the image receiving sheet is fixed on the recording drum 4 by vacuum suction through the suction hole provided in the recording drum. 3) The squeeze roller 8 comes down onto the recording drum 4, and while the image receiving sheet is being held down, the image receiving sheet is stopped by the rotation of the drum when the image receiving sheet is further conveyed by a prescribed amount, and is cut into a prescribed length by the cutter 9. 4) Further, the recording drum 4 makes one round to complete the loading of the image receiving sheet. 5) Next, in the same sequence as the image receiving sheet, the first-color-black-thermal transfer sheet K is unrolled from the thermal transfer sheet roll 10K, cut, and loaded. 6) Next, the recording drum 4 starts to rotate at a high speed, the recording head 2 on the sub-scanning rail 3 starts to move, and when the recording start position is reached, the recording head 2 irradiates the recording laser on the recording drum 4 according to the recording image signal. To be done. The irradiation is terminated at the recording end position, and the sub-scanning rail operation and the drum rotation are stopped. Return the recording head on the sub-scanning rail to the origin. 7) Only the thermal transfer sheet K is peeled off while leaving the image receiving sheet on the recording drum. Therefore, the tip of the thermal transfer sheet K is hooked with a claw, pulled out in the discharge direction, and discarded from the waste port 32 to the waste box 35. 8) Repeat 5) to 7) for the remaining three colors. The recording order is black, followed by cyan, magenta, and yellow. That is, the second color-cyan thermal transfer sheet C is sequentially transferred from the thermal transfer sheet roll 10C, the third color-magenta thermal transfer sheet M is transferred from the thermal transfer sheet roll 10M, and the fourth color-yellow thermal transfer sheet Y is sequentially transferred from the thermal transfer sheet roll 10Y. Be paid out. This is the reverse of the general printing order, but this is because the color order on the real paper is reversed by the real paper transfer in a later step. 9) When the four colors are completed, the recorded image receiving sheet is finally discharged to the discharge tray 31. The method of peeling from the drum is the same as that of the thermal transfer sheet of 7), but since it is not discarded unlike the thermal transfer sheet, it is returned to the discharge table by switchback when it reaches the disposal port 32. When discharged to the discharge table, air 34 is jetted from below the discharge port 33 to enable stacking of a plurality of sheets.

Conveying roller 7 at either the supplying portion or the conveying portion of the thermal transfer sheet roll and the image receiving sheet roll.
In addition, it is preferable to use an adhesive roll having an adhesive material on the surface.

By providing the adhesive roll, the surfaces of the thermal transfer sheet and the image receiving sheet can be cleaned.

As the adhesive material provided on the surface of the adhesive roll, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyolefin resin, polybutadiene resin, styrene-butadiene copolymer (SB
R), styrene-ethylene-butene-styrene copolymer (SEBS), acrylonitrile-butadiene copolymer (NBR), polyisoprene resin (IR), styrene-
Examples thereof include isoprene copolymer (SIS), acrylic acid ester copolymer, polyester resin, polyurethane resin, acrylic resin, butyl rubber, polynorbornene and the like.

The pressure-sensitive adhesive roll can clean the surface by contacting the surfaces of the thermal transfer sheet and the image-receiving sheet, and the contact pressure is not particularly limited as long as it is in contact.

The Vickers hardness Hv of the tacky material used for the tacky roll is 50 kg / mm ² (≈490 MPa) or less so that dust as a foreign substance can be sufficiently removed and image defects can be suppressed. Is preferred.

Vickers hardness means that the facing angle is 13
The hardness is a hardness measured by applying a static load to a 6-degree regular pyramid-shaped diamond indenter, and the Vickers hardness Hv is obtained by the following formula.

Hardness Hv = 1.854 P / d ² (kg / mm ² ) ≈1
8.1692P / d ² (MPa) Here, P: magnitude of load (kg), d: diagonal length of square of depression (mm).

Further, in the present invention, the elastic modulus at 20 ° C. of the adhesive material used for the above-mentioned adhesive roll is
It is preferably 200 kg / cm ² (≈19.6 MPa) or less, since dust as a foreign substance can be sufficiently removed and image defects can be suppressed as in the above case.

Surface roughness of the image forming layer surface of the thermal transfer sheet
The absolute value of the difference between the surface roughness Rz of Rz and its back surface layer is 3.0 or less, and the absolute value of the difference between the surface roughness Rz of the image receiving layer surface of the image receiving sheet and the surface roughness Rz of its back surface layer is 3.0. The following is preferable. With such a configuration, image defects can be prevented in cooperation with the above-mentioned cleaning means, a conveyance jam can be eliminated, and dot gain stability can be further improved.

In the present specification, the surface roughness Rz means JIS.
Rz (maximum height) is the average surface roughness of 10 points, and the average surface of the portion extracted from the curved surface of the roughness by the reference area is the reference surface Is the input value of the distance between the average value of and the average value of the depth of the valley bottom from the deepest to the fifth. For measurement, Tokyo Seimitsu Co., Ltd.
Use a stylus-type three-dimensional roughness meter (Surfcom 570A-3DF) manufactured by K.K.
The measuring direction is vertical, the cutoff value is 0.08 mm, the measuring area is 0.6 mm × 0.4 mm, the feed pitch is 0.005 mm, and the measuring speed is 0.12 mm / s.

The absolute value of the difference between the surface roughness Rz on the surface of the image forming layer and the surface roughness Rz on the surface of the back layer of the thermal transfer sheet is
It is 1.0 or less, and the absolute value of the difference between the surface roughness Rz of the image receiving layer surface of the image receiving sheet and the surface roughness Rz of the back surface of the image receiving layer is 1.0.
The following is preferable from the viewpoint of further improving the above effects.

Further, as another embodiment, it is preferable that the surface roughness of the surface of the image forming layer and the surface of the back surface of the thermal transfer sheet and / or the surface roughness Rz of the front and back surfaces of the image receiving sheet is 2 to 30 μm. With such a configuration, the image defect can be prevented in cooperation with the above-mentioned cleaning means, the conveyance jam can be eliminated, and the dot gain stability can be further improved.

The glossiness of the image forming layer of the thermal transfer sheet is
It is also preferably 80 to 99.

The glossiness largely depends on the smoothness of the surface of the image forming layer, and can affect the uniformity of the thickness of the image forming layer. Higher gloss is more uniform as an image forming layer and is more suitable for use in high-definition images. However, if smoothness is high, resistance during transportation becomes larger, and both are in a trade-off relationship.
When the glossiness is in the range of 80 to 99, both can be compatible and balanced.

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 is prepared in which the image receiving sheet 20 is laminated on the surface of the image forming layer 16 containing the black (K), cyan (C), magenta (M) or yellow (Y) pigment of the thermal transfer sheet 10. . The thermal transfer sheet 10 is the support 1
2 and on it, the photothermal conversion layer 14, and further on it,
The image receiving sheet 20 has an image forming layer 16 and a support 22.
Then, the image receiving layer 24 is provided thereon, and the image receiving layer 24 is laminated on the surface of the image forming layer 16 of the thermal transfer sheet 10 so as to be in contact with the image forming layer 16 (FIG. 1A). When the laser beam is imagewise radiated from the side of the support 12 of the thermal transfer sheet 10 of the laminated body 30, the laser light irradiation region of the photothermal conversion layer 14 of the thermal transfer sheet 10 generates heat and the image forming layer 16 is formed.
The adhesive force with is reduced (FIG. 1 (b)). After that, when the image receiving sheet 20 and the thermal transfer sheet 10 are peeled off, the laser light irradiation region 16 ′ of the image forming layer 16 becomes the image receiving sheet 2.
0 is transferred onto the image receiving layer 24 (FIG. 1C). Then, the laser light irradiation area 16 ′ of the image forming layer 16
Is the image-forming layer transferred onto the image-receiving layer by irradiation with laser light in the present invention, and in the present invention, as described above, the reflection spectrum of the image-forming layer 16 and the image-receiving layer by irradiation with laser light are formed on the image-receiving layer. The difference between the reflection spectrum of the transferred image forming layer 16 'and the reflection spectrum in the visible light region is 10% or less, or the hue when the image forming layer 16' is not exposed immediately after image recording and the light is exposed. Layers such as the photothermal conversion layer and the image forming layer of the thermal transfer sheet are configured so that the color difference from the subsequent hue is within 2.

In the multicolor image formation, the laser light used for light irradiation is preferably multi-beam light, and particularly preferably multi-beam two-dimensional array. The multi-beam two-dimensional array uses a plurality of laser beams when recording by laser irradiation, and the spot arrays of these laser beams have a plurality of rows along the main scanning direction and a plurality of spots along the sub scanning direction. It means a two-dimensional plane array consisting of rows. By using a laser beam having a multi-beam two-dimensional array, the time required for laser recording can be shortened.

The laser beam to be used can be used without particular limitation as long as it is a multi-beam, and it is a gas laser beam such as an argon ion laser beam, a helium neon laser beam, a helium cadmium laser beam, or a solid laser such as a YAG laser beam. Light, semiconductor laser light, dye laser light,
Direct laser light such as excimer laser light is used. Alternatively, light obtained by converting these laser lights into a half wavelength through a second harmonic element can also be used. In the multicolor image forming method, it is preferable to use semiconductor laser light in consideration of output power, easiness of modulation, and the like. In the multicolor image forming method, the laser beam has a beam diameter on the photothermal conversion layer of 5 to 50 μm (particularly 6 to 30 μm).
It is preferable that the irradiation is performed under the condition that the range is μm), and the scanning speed is 1 m / sec or more, preferably 3 m / sec or more, and more preferably 5 m / sec or more. The light source wavelength of the laser light is 750 to 850 nm.
Is preferred. Furthermore, the energy applied to the photothermal conversion layer at the time of recording an image by irradiating a laser beam is preferably 300 mJ / m ² or less, 20
It is particularly preferably from 0 to 250 mJ / m ² .

In multicolor image formation, the layer thickness of the image forming layer in the black thermal transfer sheet is larger than the layer thickness of the image forming layer in each of the yellow, magenta, and cyan thermal transfer sheets, and 0.5 to 0.5. It is preferably 0.7 μm. By doing so, when the black thermal transfer sheet is irradiated with a laser, it is possible to suppress a decrease in density due to uneven transfer. When the thickness of the image forming layer in the black thermal transfer sheet is less than 0.5 μm, the image density is greatly reduced due to transfer unevenness when recording with high energy, and the image density required as a proof for printing is achieved. Can be difficult. Since this tendency becomes more remarkable under high humidity conditions, the concentration change due to the environment may become large. On the other hand, when the layer thickness is more than 0.7 μm, the transfer sensitivity during laser recording may be lowered, resulting in deterioration of small dots and thin lines. This tendency is more remarkable under low humidity conditions. In addition, the resolution may deteriorate. The layer thickness of the image forming layer in the black thermal transfer sheet is more preferably 0.55 to 0.65 μm, and particularly preferably 0.60 μm.

Further, the layer thickness of the image forming layer in the black thermal transfer sheet is 0.5 to 0.7 μm, and the layer thickness of the image forming layer in each of the yellow, magenta and cyan thermal transfer sheets is 0. 0.2 μm or more and 0.5 μm
It is preferably less than. The yellow, magenta,
If the thickness of the image forming layer in each of the cyan and cyan thermal transfer sheets is less than 0.2 μm, the density may decrease due to transfer unevenness during laser recording, while 0.5 μm.
In the above, the transfer sensitivity may be lowered or the resolution may be deteriorated. More preferably, it is 0.3 to 0.45 μm.

The image forming layer in the black thermal transfer sheet preferably contains carbon black, and the carbon black is composed of at least two kinds of carbon blacks having different coloring powers. P / B (Pigment / Binder) ) It is preferable because the reflection density can be adjusted while keeping the ratio within a certain range. The coloring power of carbon black can be represented by various methods. For example, PVC described in JP-A-10-140033 is used.
Examples include blackness. The PVC blackness means that carbon black is added to PVC resin, dispersed by two rolls and made into a sheet, and carbon black “# 40” of Mitsubishi Chemical Corporation,
The blackness of "# 45" is set to 1 point and 10 points, respectively, and a reference value,
The blackness of the sample is evaluated by visual judgment. PV
Two or more kinds of carbon blacks having different C blacknesses can be appropriately selected and used according to the purpose.

Hereinafter, a specific method for preparing a sample will be described. <Sample preparation method> 40% by mass of sample carbon black was blended with LDPE (low density polyethylene) resin in a 250 cc Banbury mixer, and kneading was performed at 115 ° C for 4 minutes. Compounding conditions LDPE resin 101.89 g Calcium stearate 1.39 g Irganox 1010 0.87 g Sample carbon black 69.43 g Next, it is diluted at 120 ° C. by a two-roll mill so that the carbon black concentration becomes 1% by mass.

Diluted compound preparation conditions LDPE resin 58.3 g Calcium stearate 0.2 g Carbon black 40% by mass mixed resin 1.5 g Slit width 0.3 mm is made into a sheet, and this sheet is cut into chips and placed on a 240 ° C. hot plate. 65 ± 3 μm
To form a film.

As a method of forming a multicolor image, as described above, the thermal transfer sheet is used, and a large number of image layers (image forming layers on which images are formed) are repeatedly superposed on the same image receiving sheet. A color image may be formed, or a multicolor image may be formed by once forming an image on the image receiving layers of a plurality of image receiving sheets and then retransferring the image onto a printing paper or the like.
Regarding the latter, for example, a thermal transfer sheet having an image forming layer containing colorants having mutually different hues is prepared, and four types (four colors: four color: four color: (Cyan, magenta, yellow, black) manufactured. To each laminate, for example, through a color separation filter, laser light irradiation according to a digital signal based on the image is performed, and subsequently, the thermal transfer sheet and the image receiving sheet are peeled off, and a color separation image of each color is formed on each image receiving sheet. Are formed independently. Next, each color separation image formed is
A multicolor image can be formed by sequentially laminating a separately prepared actual support such as printing paper or a support similar thereto.

In thermal transfer recording using laser light irradiation, a laser beam is converted into heat and the thermal energy is used to transfer an image forming layer containing a pigment onto an image receiving sheet to form an image on the image receiving sheet. If there is a pigment at the time of transfer,
The state change of the dye or the image forming layer is not particularly limited, and includes any of a solid state, a softened state, a liquid state, and a gas state, but the solid state or the softened state is preferable. Thermal transfer recording using laser light irradiation includes, for example, conventionally known fusion type transfer, transfer by ablation, sublimation type transfer and the like. Above all, thin film transfer type, melting
The ablation type is preferable in that it produces an image having a hue similar to that of printing.

A thermal laminator is usually used to perform the step of transferring the image-receiving sheet on which the image is printed by the recording device to the actual printing paper (referred to as "main paper"). When the image-receiving sheet and the main paper are superposed and heat and pressure are applied, the two adhere to each other, and when the image-receiving sheet is peeled off from the main paper, only the image-receiving layer containing the image remains on the main paper. By connecting the above apparatus to the plate making system, a system capable of exhibiting a function as a color proof is constructed. As a system, it is necessary for the recording device to output a printed matter with an image quality as close as possible to a printed matter output from certain plate-making data. Therefore, software is needed to bring colors and halftone dots closer to the printed matter. A specific connection example is given below. When proofing a printed matter from a plate-making system (for example, Celebra manufactured by Fuji Photo Film Co., Ltd.), the system connection is as follows. A CTP (Computer To Plate) system is connected to the plate making system.
A final printed matter is obtained by applying the printing plate thus output to a printing machine. The above-mentioned recording device is connected to the plate-making system as a color proof, while the PD system (registered trademark) is connected as proof drive software for bringing colors and halftone dots closer to the printed matter. The contone (continuous tone) data converted to raster data by the plate making system is converted to halftone dot binary data, output to the CTP system, and finally printed. On the other hand, the same contone data is also output to the PD system. The PD system converts the received data by a four-dimensional (black, cyan, magenta, yellow) table so as to match the color of the printed matter. Finally, it is converted into halftone dot binary data so as to match the halftone dot of the printed matter, and output to the recording device. The four-dimensional table is experimentally created in advance and stored in the system. The experiment for making is as follows. Prepare an image in which important color data is printed via the CTP system and an image output from a recording device via the PD system, compare the colorimetric values, and create a table to minimize the difference.

The thermal transfer sheet and the image receiving sheet which are preferably used in the recording apparatus of the above system will be described below. [Thermal Transfer Sheet] The thermal transfer sheet has at least a photothermal conversion layer and an image forming layer on a support, and further has other layers as necessary.

(Support) The material of the support of the thermal transfer sheet is not particularly limited, and various support materials can be used according to the purpose. The support is preferably rigid, has good dimensional stability, and can withstand heat during image formation. Preferred examples of the support material include polyethylene terephthalate, polyethylene-2,6-naphthalate, polycarbonate, polymethylmethacrylate, polyethylene,
Polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene-acrylonitrile copolymer, polyamide (aromatic or aliphatic), polyimide,
Examples thereof include synthetic resin materials such as polyamide imide and polysulfone. Of these, biaxially oriented polyethylene terephthalate is preferable in consideration of mechanical strength and dimensional stability against heat. When used in the production of a color proof utilizing laser recording, the support of the thermal transfer sheet is preferably made of a transparent synthetic resin material that transmits laser light. The thickness of the support is 25 to 130 μm
Is preferable, and 50 to 120 μm is particularly preferable. The center line average surface roughness Ra (measured according to JIS B0601 using a surface roughness measuring instrument (Surfcom, manufactured by Tokyo Seiki Co., Ltd.)) of the support on the image forming layer side may be less than 0.1 μm. preferable. Young's modulus in the longitudinal direction of the support is 200 to 1200 Kg / mm
² (≈2 to 12 GPa) is preferable, and the Young's modulus in the width direction is 250 to 1600 Kg / mm ² (≈2.5 to 16 GP
It is preferably a). F-5 in the longitudinal direction of the support
The value is preferably 5 to 50 Kg / mm ² (≈49 to 49
0 MPa), and the F-5 value in the width direction of the support is preferably 3
˜30 Kg / mm ² (≈29.4 to 294 MPa), and the F-5 value in the support longitudinal direction is F-5 in the support width direction.
It is generally higher than the value, but not particularly when it is necessary to increase the strength in the width direction. The heat shrinkage ratio of the support in the longitudinal and width directions at 100 ° C. for 30 minutes is preferably 3% or less, more preferably 1.5% or less, and the heat shrinkage ratio at 80 ° C. for 30 minutes is preferably 1%. Less than,
More preferably, it is 0.5% or less. Breaking strength is 5 to 100 kg / mm ^{2 in} both directions (≈49 to 980 MP
a), the elastic modulus is 100 to 2000 Kg / mm ² (≈0.
98 to 19.6 GPa) is preferable.

The support of the thermal transfer sheet is subjected to a surface activation treatment and / or an attachment of one or two or more undercoat layers in order to improve the adhesion to the photothermal conversion layer provided thereon. Good. Examples of the surface activation treatment include glow discharge treatment and corona discharge treatment. It is preferable that the material of the undercoat layer has high adhesiveness to both surfaces of the support and the photothermal conversion layer, has low thermal conductivity, and has excellent heat resistance. Examples of the material of such an 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. If necessary, various kinds of functional layers such as an antireflection layer and an antistatic layer may be attached to the surface of the thermal transfer sheet opposite to the side where the photothermal conversion layer is attached, or surface treatment may be performed.

(Back Layer) It is preferable to provide a back layer on the surface of the thermal transfer sheet of the present invention on the side opposite to the side on which the photothermal conversion layer is provided. The back layer is preferably composed of two layers, a first back layer adjacent to the support and a second back layer provided on the opposite side of the first back layer from the support. In the present invention, the ratio B / A of the mass A of the antistatic agent contained in the first back layer and the mass B of the antistatic agent contained in the second back layer is preferably less than 0.3.
When B / A is 0.3 or more, the slipperiness and the powder drop of the back layer tend to be deteriorated.

The layer thickness C of the first back layer is 0.01 to 1 μm.
It is preferably m, and more preferably 0.01 to 0.2 μm. Also, the layer thickness D of the second back layer
Is preferably 0.01 to 1 μm, and 0.01 to
More preferably, it is 0.2 μm. The layer thickness ratio C: D of the first and second back layers is preferably 1: 2 to 5: 1.

As the antistatic agent used in the first and second back layers, polyoxyethylene alkylamine,
Nonionic surfactants such as glycerin fatty acid ester,
Compounds such as cationic surfactants such as quaternary ammonium salts, anionic surfactants such as alkyl phosphates, amphoteric surfactants and conductive resins can be used.

Further, the conductive fine particles are used as an antistatic agent.
You can also As such conductive fine particles,
For example, ZnO, TiO₂, SnO₂, Al₂O₃, In₂
O₃, MgO, BaO, CoO, CuO, Cu₂O, Ca
O, SrO, BaO₂, PbO, PbO₂, MnO₃, M
oO₃, SiO₂, ZrO₂, Ag₂O, Y₂O₃, Bi
₂O₃, Ti₂O₃, Sb₂O₃, Sb₂O_Five, K₂Ti₆O₁₃,
NaCaP₂O₁₈, MgB₂O _FiveOxides such as CuS, Z
Sulfides such as nS; SiC, TiC, ZrC, VC, Nb
Carbides such as C, MoC, WC; Si₃N_Four, TiN, Zr
N, VN, NbN, Cr₂N and other nitrides; TiB₂, Zr
B₂, NbB₂, TaB₂, CrB, MoB, WB, La
B_FiveBoride; TiSi₂, ZrSi₂, NbSi₂, T
aSi₂, CrSi₂, MoSi₂, WSi₂And other silicides;
BaCO₃, CaCO₃, SrCO₃, BaSO_Four, CaS
O_FourMetal salts such as SiN_Four-SiC, 9Al₂O₃-2B₂
O₃And the like, and one of these may be used alone or 2
You may use together 1 or more types. Of these, SnO₂, Z
nO, Al₂O₃, TiO₂, In₂O₃, MgO, BaO
And MoO₃Is preferred, SnO₂, ZnO, In₂O₃Over
And TiO₂Is more preferable, and SnO₂Is particularly preferable.

When the thermal transfer material of the present invention is used in a laser thermal transfer recording system, the antistatic agent used in the back layer is preferably substantially transparent so that the laser light can be transmitted therethrough.

When a conductive metal oxide is used as an antistatic agent, its particle size is preferably as small as possible in order to minimize light scattering, but the ratio of the refractive index of the particles to the binder is used as a parameter. It should be determined and can be determined using Mie's theory. Generally, the average particle size is in the range of 0.001 to 0.5 μm, preferably 0.003 to 0.2 μm. Here, the average particle diameter is a value that includes not only the primary particle diameter of the conductive metal oxide but also the particle diameter of the higher-order structure.

In addition to the antistatic agent, various additives and binders such as a surfactant, a slip agent and a matting agent can be added to the first and second back layers. The amount of the antistatic agent contained in the first back layer is preferably 10 to 1000 parts by mass, and 200 to 80 parts by mass with respect to 100 parts by mass of the binder.
0 mass part is more preferable. Further, the amount of the antistatic agent contained in the second back layer is preferably 0 to 300 parts by mass, more preferably 0 to 100 parts by mass with respect to 100 parts by mass of the binder.

As the binder used for forming the first and second back layers, for example, homopolymers and copolymers of acrylic acid type monomers such as acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. , Nitrocellulose, methyl cellulose, ethyl cellulose,
Cellulosic polymers such as cellulose acetate,
Polyethylene, polypropylene, polystyrene, vinyl chloride copolymers, vinyl chloride-vinyl acetate copolymers, polyvinylpyrrolidone, polyvinyl butyral, copolymers of vinyl compounds and vinyl compounds such as polyvinyl alcohol, polyesters, polyurethanes, polyamides Examples thereof include condensation-type polymers, rubber-based thermoplastic polymers such as butadiene-styrene copolymer, polymers obtained by polymerizing and crosslinking photopolymerizable or thermopolymerizable compounds such as epoxy compounds, and melamine compounds. .

(Light-to-heat conversion layer) The light-to-heat conversion layer contains a light-to-heat conversion substance, a binder, and optionally a matting agent,
Further, other components are contained if 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) capable of absorbing laser light. When an image is recorded with an infrared laser, an infrared absorbing dye is preferably used as the photothermal conversion substance. Examples of the dyes include black pigments such as carbon black, pigments of macrocyclic compounds 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 thereof 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, the cyanine dye exhibits a high extinction coefficient with respect to light in the infrared region. Therefore, when it is used as a photothermal conversion substance, the photothermal conversion layer can be thinned, and as a result, the recording sensitivity of the thermal transfer sheet can be improved. It is preferable because it can be further improved.

Among the cyanine dyes, in order to realize the multicolor image forming material of the present invention which can prevent the dye from transferring to the image forming layer at the time of laser recording and can obtain an image having a good hue, A cyanine dye having a structure represented by formula (A) is particularly preferable.

[0063]

[Chemical 3]

In the general formula (A), Z represents an atomic group for forming a benzene ring, a naphthalene ring or a heteroaromatic ring, and among them, a benzene ring and a naphthalene ring are preferable. T
Is -O -, - S -, - Se -, - N (R 1) -, - C
(R ² ) (R ³ ) — or —C (R ⁴ ) ═C (R ⁵ ) —, wherein R ¹ , R ² and R ³ each independently represent an alkyl group, an alkenyl group or an aryl group. , R ⁴ and R ⁵ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a carboxyl group, an acyl group, an acylamino group, a carbamoyl group, a sulfamoyl group or a sulfonamide group. Represent Among them, T is preferably —CH ₂ — or —S—. L represents a trivalent linking group formed by linking 5 or 7 methine groups by a conjugated double bond, and specifically,

[0065]

[Chemical 4]

Is preferred. M represents a divalent linking group, 2
Included are alkylene groups having from 5 carbon atoms.
Examples of X include NH ₄ and NEt ₄ .

As the light-heat conversion substance, an inorganic material such as a particulate metal material such as blackened silver can be used in addition to the dye.

The binder contained in the photothermal conversion layer has at least the strength capable of forming a layer on the support,
Resins with high thermal conductivity are preferred. Furthermore, when the resin is a heat-resistant resin that does not decompose even by the heat generated from the photothermal conversion substance during image recording, the smoothness of the surface of the photothermal conversion layer after light irradiation is achieved even when high-energy light irradiation is performed. Is preferable because it can be maintained. Specifically, the thermal decomposition temperature (T
A resin having a temperature increase rate of 10 ° C./min by the GA method (temperature at which 5% mass is reduced in an air stream) of 400 ° C. or higher is preferable, and a resin having a thermal decomposition temperature of 500 ° C. or higher is preferable. More preferable. Further, the binder is 200 to 400 ° C.
It preferably has a glass transition temperature of 250 to 35
More preferably it has a glass transition temperature of 0 ° C. If the glass transition temperature is lower than 200 ° C., fog may occur in the formed image, and if it is higher than 400 ° C., the solubility of the resin may be lowered and the production efficiency may be lowered.
The heat resistance of the binder of the photothermal conversion layer (for example, thermal deformation temperature or thermal decomposition temperature) is preferably higher than the materials used for other layers provided on the photothermal conversion layer. Further, the binder preferably has an SP value of 25 or more, which is derived by the Okitsu method, from the viewpoint of compatibility with the dye. For the Okitsu method, see the Journal of Adhesion Society of Japan,
Vol. 29, No. 5 (1993).

Specifically, acrylic acid resins such as polymethylmethacrylate, polycarbonate, polystyrene,
Vinyl chloride / vinyl acetate copolymer, vinyl resin such as polyvinyl alcohol, polyvinyl butyral, polyester, polyvinyl chloride, polyamide, polyimide, polyetherimide, polysulfone, polyether sulfone, aramid, polyurethane, epoxy resin, urea / melamine Resin etc. are mentioned. Among these, a resin containing an imide bond such as a polyimide resin is preferable.

Examples of the matting agent contained in the photothermal conversion layer include inorganic fine particles and organic fine particles. The inorganic fine particles include silica, titanium oxide, aluminum oxide, zinc oxide, magnesium oxide, barium sulfate, magnesium sulfate, aluminum hydroxide, magnesium hydroxide, metal salts such as boron nitride, kaolin, clay, talc, zinc white, Lead white, Sieglite, quartz, diatomaceous earth, barlite, bentonite, mica, synthetic mica, etc. may be mentioned. As the organic fine particles, fluororesin particles,
Examples thereof include resin particles such as guanamine resin particles, acrylic resin particles, styrene-acrylic copolymer resin particles, silicone resin particles, melamine resin particles, and epoxy resin particles.

The particle size of the matting agent is usually 0.3 to 30 μm.
m, preferably 0.5 to 20 μm, and the addition amount is preferably 0.1 to 100 mg / m ² .

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

The light-heat converting layer is prepared by dissolving a light-heat converting substance and a binder, and adding a matting agent and other components as necessary to prepare a coating solution, which is coated on a support and dried. It can be provided. Examples of the organic solvent for dissolving the polyimide resin include n
-Hexane, cyclohexane, diglyme, xylene,
Toluene, ethyl acetate, tetrahydrofuran, methyl ethyl ketone, acetone, cyclohexanone, 1,4-dioxane, 1,3-dioxane, dimethyl acetate,
N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, γ
-Butyrolactone, ethanol, methanol and the like. The coating and drying can be carried out by using ordinary coating and drying methods. Drying is usually performed at a temperature of 300 ° C. or lower, and preferably at a temperature of 200 ° C. or lower. When polyethylene terephthalate is used as the support, it is preferably dried at a temperature of 80 to 150 ° C.

When the amount of the binder in the light-heat conversion layer is too small, the cohesive force of the light-heat conversion layer is reduced, and when the formed image is transferred to the image-receiving sheet, the light-heat conversion layer is easily transferred together with the image-forming sheet, and the image formation of the image is reduced. This will cause color mixing. On the other hand, when the amount of the polyimide resin is too large, the layer thickness of the photothermal conversion layer is increased in order to achieve a constant light absorption rate, and the sensitivity is likely to be lowered. The solid content mass ratio of the photothermal conversion substance and the binder in the photothermal conversion layer is preferably 1:20 to 2: 1, and more preferably 1:10 to 2: 1.
Further, it is preferable to make the light-heat conversion layer thin, because the heat transfer sheet can have high sensitivity as described above. The photothermal conversion layer preferably has a thickness of 0.03 to 1.0 μm, and preferably 0.0 to 1.0 μm.
More preferably, it is 5 to 0.5 μm. Further, the light-heat conversion layer is 0.80 to 1.
The optical density of 26 is preferable because the transfer sensitivity of the image forming layer is improved.
It is more preferable to have an optical density of 2 to 1.15.
When the optical density at the laser peak wavelength is less than 0.80, it becomes insufficient to convert the irradiated light into heat and the transfer sensitivity may decrease. On the other hand, when it exceeds 1.26, the function of the photothermal conversion layer is affected during recording, and fogging may occur.

(Image-Forming Layer) The image-forming layer contains at least a pigment for forming an image by being transferred to an image-receiving sheet, and further contains a binder for forming a layer and, if desired, other components. To do. Pigments are generally roughly classified into organic pigments and inorganic pigments, the former having particularly excellent transparency of the coating film, and the latter generally having properties such as excellent hiding properties, so that they can be appropriately selected depending on the application. Good. When the thermal transfer sheet is used for printing color proofing, an organic pigment that has a color tone that matches or is close to yellow, magenta, cyan, and black generally used for printing ink is preferably used. In addition, metal powder, fluorescent pigment, etc. may also be used. Examples of suitable pigments include azo pigments, phthalocyanine pigments, anthraquinone pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, and nitro pigments. The pigments used in the image forming layer are listed below according to hues, but the pigments are not limited to these.

1) Yellow Pigment Pigment Yellow (Pigment Yellow)
12 (C.I. No. 21090) Example) Permanent Yellow (Permanent Yellow) DHG (Clariant Japan KK)
Manufactured by Toyo Ink Mfg. Co., Ltd., Irg
alite Yellow (Irgarite yellow)
LCT (Ciba Specialty Chemicals Co., Ltd.)
), SYMLER FAST YELLOW (Shimla Fast Yellow) GTF 219 (Dainippon Ink and Chemicals, Inc.) Pigment Yellow (Pigment Yellow)
13 (CI. No. 21100) Example) Permanent Yellow (Permanent Yellow) GR (manufactured by Clariant Japan Co., Ltd.),
Lionol Yellow (Rionol Yellow)
1313 (manufactured by Toyo Ink Mfg. Co., Ltd.) Pigment Yellow (Pigment Yellow)
14 (CI. No. 21095) Example) Permanent Yellow (Permanent Yellow) G (manufactured by Clariant Japan KK), L
ionol Yellow 1
401-G (manufactured by Toyo Ink Mfg. Co., Ltd.), Seika
Fast Yellow
2270 (manufactured by Dainichiseika Kogyo Co., Ltd.), Symler
Fast Yellow (Shimla First Yellow) 4400 (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Yellow (Pigment Yellow)
17 (C.I. No. 21105) Example) Permanent Yellow (Permanent Yellow) GG02 (Clariant Japan KK)
Manufactured by SYMLER FAST Yellow (Shimla First Yellow) 8GF (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Yellow
155 Example) Graphtol Yellow (Graph Thor Yellow) 3GP (Clariant Japan KK) Pigment Yellow (Pigment Yellow)
180 (CI No. 21290) Example) Novoperm Yellow (Novopalm Yellow) P-HG (manufactured by Clariant Japan KK),
PV Fast Yellow (First Yellow)
HG (Clariant Japan KK) Pigment Yellow (Pigment Yellow)
139 (C.I.No. 56298) Example) Novoperm Yellow (Novopalm Yellow) M2R 70 (Clariant Japan KK)
Made)

2) Magenta Pigment Pigment Red 57:
1 (C.I.No. 15850: 1) Example) Graphtol Rubin (Graphtor Rubin) L6B (manufactured by Clariant Japan KK), L
ionol Red 6B-42
90G (Toyo Ink Mfg. Co., Ltd.), Irgalite
Rubine (Irgarite Rubin) 4BL (Ciba Specialty Chemicals Co., Ltd.), Symu
ler Brilliant Carmine 6B-229 (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red (Pigment Red) 122
(C.I. No. 73915) Example) Hosterm Pink (Hoster Palm Pink) E (manufactured by Clariant Japan KK), Li
onogen Magenta (Rionogen Magenta)
5790 (manufactured by Toyo Ink Mfg. Co., Ltd.), Fastog
en Super Magenta RH (Dainippon Ink and Chemicals, Inc.)
Made) Pigment Red (Pigment Red) 53:
1 (C.I.No. 15585: 1) Example) Permanent Lake Red (Permanent Lake Red) LCY (Clariant Japan KK), Symul
er Lake Red (Shimla Lake Red) C
conc (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red (Pigment Red) 48:
1 (C.I.No. 15865: 1) Example) Lionol Red (Lionol Red) 2B
3300 (manufactured by Toyo Ink Mfg. Co., Ltd.), Symule
r Red (Shimla Red) NRY (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red (Pigment Red) 48:
2 (C.I.No. 15865: 2) Example) Permanent Red (Permanent Red) W2T (manufactured by Clariant Japan KK), Li
onol Red (Rionol Red) LX235
(Manufactured by Toyo Ink Mfg. Co., Ltd.), Symboler Red
(Shimla Red) 3012 (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red 48:
3 (C.I.No. 15865: 3) Example) Permanent Red (Permanent Red) 3RL (Clariant Japan KK), Sy
muller Red 2BS (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red 177
(C.I. No. 65300) Example) Cromophthal Red (Chromophtal red) A2B (manufactured by Ciba Specialty Chemicals Co., Ltd.)

3) Cyan Pigment Pigment Blue 15
(C.I. No. 74160) Example) Lionol Blue (Lionol Blue) 7
027 (manufactured by Toyo Ink Mfg. Co., Ltd.), Fastogen
Blue (Fastgen Blue) BB (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue (Pigment Blue) 1
5: 1 (C.I. No. 74160) Example) Hosterm Blue (Hoster Palm Blue) A2R (manufactured by Clariant Japan KK),
Fastogen Blue (Fastgen Blue)
5050 (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue (Pigment Blue) 1
5: 2 (C.I. No. 74160) Example) Hosterm Blue (Hoster Palm Blue) AFL (manufactured by Clariant Japan Co., Ltd.),
Irgalite Blue (Irgalite blue)
BSP (Ciba Specialty Chemicals Co., Ltd.)
Fastogen Blue (Fastgen Blue) GP (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue (Pigment Blue) 1
5: 3 (C.I. No. 74160) Example) Hosterm Blue (Hoster Palm Blue) B2G (manufactured by Clariant Japan Co., Ltd.),
Lionol Blue FG7330 (manufactured by Toyo Ink Mfg. Co., Ltd.), Cromo
phtal Blue (chromophtal blue) 4GN
P (manufactured by Ciba Specialty Chemicals Co., Ltd.),
Fastogen Blue (Fastgen Blue)
FGF (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue (Pigment Blue) 1
5: 4 (C.I. No. 74160) Example) Hosterm Blue (Hoster Palm Blue) BFL (manufactured by Clariant Japan Co., Ltd.),
Cyanine Blue (cyanine blue) 700-10FG (manufactured by Toyo Ink Mfg. Co., Ltd.), Irg
alite Blue (Ilgarite blue) GLN
F (manufactured by Ciba Specialty Chemicals Co., Ltd.),
Fastogen Blue (Fastgen Blue)
FGS (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue (Pigment Blue) 1
5: 6 (C.I. No. 74160) Example) Lionol Blue (Lionol Blue) E
S (manufactured by Toyo Ink Mfg. Co., Ltd.) Pigment Blue (Pigment Blue) 60
(C.I. No. 69800) Example) Hosterperm Blue (Hoster Palm Blue) RL01 (Clariant Japan KK)
Manufactured by Toyo Ink Mfg. Co., Ltd.), Lionogen Blue (Lionogen Blue) 6501

4) Black Pigment Pigment Black (Pigment Black)
7 (Carbon black CI No. 77266) Example) Mitsubishi carbon black MA100 (manufactured by Mitsubishi Chemical Co., Ltd.), Mitsubishi carbon black # 5 (manufactured by Mitsubishi Chemical Co., Ltd.), Black Pearls (Black Pearls) 430 (Cabot) Co. (Cabot)
Further, as a pigment that can be used in the present invention, "Pigment Handbook, edited by Japan Pigment Technology Association, Seibundo Shinkosha, 198"
9 ”,“ COLOUR INDEX, THE SOCIETY OF
DYES & COLOURIST, THIRD EDITION, 1987 "
It is possible to select an appropriate product by referring to the above.

The average particle size of the pigment is 0.03 to
1 μm is preferable, and 0.05 to 0.5 μm is more preferable. When the particle size is less than 0.03 μm, the dispersion cost may increase or the dispersion may cause gelation,
On the other hand, if it exceeds 1 μm, coarse particles in the pigment may impair the adhesion between the image forming layer and the image receiving layer, and
The transparency of the image forming layer may be hindered.

The binder of the image forming layer is preferably an amorphous organic high molecular polymer having a softening point of 40 to 150 ° C. Examples of the amorphous organic polymer include butyral resin, polyamide resin, polyethyleneimine resin, sulfonamide resin, polyester polyol resin, petroleum resin, styrene, vinyltoluene, α-methylstyrene, 2-methylstyrene, Chlorostyrene, vinyl benzoic acid, sodium vinyl benzene sulfonate, styrene and its derivatives such as aminostyrene, substituted homopolymers and copolymers, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate and other methacrylic acid esters. And acrylic acid esters such as methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate and α-ethylhexyl acrylate, and dienes such as acrylic acid, butadiene and isoprene, and acene. Use of vinyl monomers such as lilonitrile, vinyl ethers, maleic acid and maleic acid esters, maleic anhydride, cinnamic acid, vinyl chloride and vinyl acetate, or a copolymer with other monomers. You can Two or more kinds of these resins may be mixed and used.

The image forming layer preferably contains 30 to 70% by mass of the pigment, more preferably 30 to 50% by mass. The image forming layer is made of resin 70
It is preferably contained in an amount of 30 to 30% by mass, more preferably 70 to 40% by mass.

The image forming layer may contain the following components (1) to (3) as the other components. Waxes Examples of waxes include mineral waxes, natural waxes, and synthetic waxes. Examples of the mineral waxes include petroleum wax such as paraffin wax, microcrystalline wax, ester wax, and oxidized wax, montan wax, ozokerite, ceresin, and the like. Of these, paraffin wax is preferable. The paraffin wax is separated from petroleum and various types are commercially available depending on the melting point thereof. Examples of the natural waxes include plant waxes such as carnauba wax, wood wax, auricurie wax, and espal wax, and animal waxes such as dense wax, insect wax, shellac wax, and whale wax.

The above synthetic wax is generally used as a lubricant, and is usually composed of a higher fatty acid compound. Examples of such synthetic waxes include the following. 1) Fatty acid wax A linear saturated fatty acid represented by the following general formula: CH ₃ (CH ₂ ) _n COOH In the above formula, n represents an integer of 6 to 28. Specific examples include stearic acid, behenic acid, palmitic acid, 12-hydroxystearic acid and azelaic acid.
In addition, metal salts of the above fatty acids (for example, K, Ca, Z
n, Mg, etc.). 2) Fatty Acid Ester Wax Specific examples of the fatty acid ester include ethyl stearate, lauryl stearate, ethyl behenate, hexyl behenate, and behenyl myristate. 3) Fatty Acid Amide Wax Specific examples of the fatty acid amide include stearic acid amide and lauric acid amide. 4) a linear saturated aliphatic alcohols represented by an aliphatic alcohol wax represented by the following general formula: CH ₃ (CH _{2) n} OH wherein formula, n represents an integer of 6 to 28. Specific examples include stearyl alcohol and the like.

Among the above synthetic waxes 1) to 4), higher fatty acid amides such as stearic acid amide and lauric acid amide are particularly preferable. The wax compounds may be used alone or in combination as required.

Plasticizer As the plasticizer, an ester compound is preferable, and dibutyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, dilauryl phthalate, butyl lauryl phthalate, Phthalates such as butylbenzyl phthalate, adipic acid di (2-
Aliphatic dibasic acid esters such as ethylhexyl) and di (2-ethylhexyl) sebacate, tricresyl phosphate, phosphoric acid triesters such as tri (2-ethylhexyl) phosphate, polyol polyesters such as polyethylene glycol ester, epoxy Known plasticizers such as epoxy compounds such as fatty acid esters can be used. Among these, esters of vinyl monomers, particularly esters of acrylic acid or methacrylic acid, are preferable because they have a large effect of improving transfer sensitivity and transfer unevenness, and a large effect of controlling elongation at break.

Examples of the ester compound of acrylic acid or methacrylic acid include polyethylene glycol dimethacrylate, 1,2,4-butanetriol trimethacrylate, trimethylolethane triacrylate, pentaerythritol acrylate, pentaerythritol tetraacrylate and dipentaerythritol. Polyacrylate etc. are mentioned.

Further, the plasticizer may be a polymer, and among them, polyester is preferable because it has a large effect of addition and is difficult to diffuse under storage conditions. Examples of the polyester include sebacic acid type polyester and adipic acid type polyester. The additives contained in the image forming layer are not limited to these. The plasticizers may be used alone or in combination of two or more.

When the content of the above-mentioned additive in the image forming layer is too large, the resolution of the transferred image is lowered, the film strength of the image forming layer itself is lowered, and the adhesion between the photothermal conversion layer and the image forming layer is decreased. Transfer of the unexposed portion to the image receiving sheet may occur due to the decrease in force. From the above viewpoint, the content of the waxes is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass of the total solid content in the image forming layer. Further, the content of the plasticizer is preferably 0.1 to 20% by mass, and more preferably 0.1 to 10% by mass of the total solid content in the image forming layer.

Others The image-forming layer further comprises, in addition to the above components, a surfactant,
Inorganic or organic fine particles (metal powder, silica gel, etc.), oils (linseed oil, mineral oil, etc.), thickeners, antistatic agents, etc. may be contained. The energy required for transfer can be reduced by including a substance that absorbs the wavelength of the light source used for image recording, except when a black image is obtained. The substance that absorbs the wavelength of the light source may be either a pigment or a dye, but in the case of obtaining a color image, an infrared light source such as a semiconductor laser is used for image recording, and there is little absorption in the visible region. It is preferable for color reproduction to use a dye having a large absorption of the wavelength of the light source. Examples of near infrared dyes include
The compounds described in JP-A-3-103476 can be mentioned.

The image forming layer is prepared by preparing a coating solution in which a pigment and the binder and the like are dissolved or dispersed, and coating the solution on the photothermal conversion layer (when a heat-sensitive peeling layer described later is provided on the photothermal conversion layer, It can be provided by coating on the layer) and drying. Examples of the solvent used for preparing the coating solution include n-propyl alcohol, methyl ethyl ketone, propylene glycol monomethyl ether (MFG), methanol, water and the like. The coating and drying can be carried out by using ordinary coating and drying methods.

On the light-heat conversion layer of the thermal transfer sheet,
Providing a heat-sensitive peeling layer containing a heat-sensitive material that generates gas by the action of heat generated in the photothermal conversion layer or releases adhered water etc., thereby weakening the bonding strength between the photothermal conversion layer and the image forming layer. You can Examples of such a heat-sensitive material include a compound (polymer or low-molecular compound) that itself decomposes or deteriorates by heat to generate a gas, or a compound (polymer that absorbs or adsorbs a considerable amount of easily vaporizable gas such as water). Alternatively, a low molecular weight compound) or the like can be used. You may use these together.

Examples of the polymer which decomposes or deteriorates by heat to generate a gas include self-oxidizing polymers such as nitrocellulose, chlorinated polyolefin, chlorinated rubber, polychlorinated rubber, polyvinyl chloride and polyvinylidene chloride. Such halogen-containing polymers, acrylic polymers such as polyisobutyl methacrylate where volatile compounds such as water are adsorbed, cellulose esters such as ethyl cellulose where volatile compounds such as water are adsorbed, volatile compounds such as water Examples thereof include natural polymer compounds such as adsorbed gelatin. Examples of the low molecular weight compound that decomposes or deteriorates by heat to generate a gas include a compound such as a diazo compound or an azide, which generates a gas upon exothermic decomposition. In addition, it is preferable that the above-described decomposition and deterioration of the heat-sensitive material occur at 280 ° C. or less, and particularly at 230 ° C. or less.

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, it is possible to use the above-mentioned polymer which itself decomposes or deteriorates by heat to generate gas, but it is also possible to use an ordinary binder having no such property. When the heat-sensitive low molecular weight compound and the binder are used in combination, the mass ratio of the former and the latter is preferably 0.02: 1 to 3: 1.
More preferably, it is 0.05: 1 to 2: 1. The heat-sensitive peeling layer preferably covers the photothermal conversion layer over substantially the entire surface thereof, and the thickness thereof is generally 0.03 to.
It is 1 μm, preferably in the range of 0.05 to 0.5 μm.

On the support, a photothermal conversion layer, a heat-sensitive peeling layer,
In the case of the thermal transfer sheet in which the image forming layers are laminated in this order, the heat-sensitive peeling layer is decomposed and deteriorated by the heat transmitted from the photothermal conversion layer to generate gas. Due to this decomposition or generation of gas, the heat-sensitive peeling layer partially disappears, or cohesive failure occurs in the heat-sensitive peeling layer, and the binding force between the photothermal conversion layer and the image forming layer is reduced. Therefore, depending on the behavior of the heat-sensitive peeling layer, a part of the heat-sensitive peeling layer may adhere to the image forming layer and appear on the surface of the finally formed image, which may cause color mixing of the image. Therefore, even if such transfer of the heat-sensitive peeling layer occurs, the heat-sensitive peeling layer is hardly colored, that is, high in visible light, so that visual color mixing does not appear in the formed image. It is desirable to show permeability. Specifically, the light absorption of the heat-sensitive release layer is 50% or less, preferably 1 with respect to visible light.
It is 0% or less. Incidentally, instead of providing an independent heat-sensitive peeling layer on the heat transfer sheet, the heat-sensitive material is added to the light-heat converting layer coating liquid to form a light-heat converting layer, so that the light-heat converting layer and the heat-sensitive peeling layer may be used together. It is also possible to have a different configuration.

The coefficient of static friction of the outermost layer of the thermal transfer sheet on the side where the image forming layer is coated is preferably 0.35 or less, and more preferably 0.20 or less. By setting the coefficient of static friction of the outermost layer to 0.35 or less, it is possible to eliminate stains on the roll when the thermal transfer sheet is conveyed and to improve the quality of the formed image. The measuring method of the static friction coefficient is Japanese Patent Application No. 2000-85759.
Paragraph (0011) in accordance with the method described above. Smoother value on the surface of the image forming layer is 0.5 to 50 mmHg (≒ 0.06 at 23 ℃, 55% RH)
65 to 6.65 kPa) is preferable, and Ra is 0.05 to
The thickness is preferably 0.4 μm, which makes it possible to reduce a large number of microscopic voids in which the image receiving layer and the image forming layer cannot come into contact with each other on the contact surface, which is preferable in terms of transfer and image quality. The Ra value is measured by a surface roughness measuring device (Surfcom,
It can be measured based on JIS B0601 by using, for example, Tokyo Seiki Co., Ltd.). The surface hardness of the image forming layer is preferably 10 g or more with a sapphire needle. After charging the thermal transfer sheet according to the US Federal Test Standard 4046, the charging potential of the image forming layer 1 second after the thermal transfer sheet is grounded is preferably −100 to 100V. The surface resistance of the image forming layer is preferably 10 ⁹ Ω or less at 23 ° C. and 55% RH.

Next, an image receiving sheet that can be used in combination with the thermal transfer sheet will be described. [Image-Receiving Sheet] (Layer Structure) The image-receiving sheet is usually a support and a support thereon.
One or more image receiving layers are provided, and if desired, one or more layers of a cushion layer, a peeling layer, and an intermediate layer are provided between the support and the image receiving layer. Further, it is preferable to have a back layer on the surface of the support opposite to the image receiving layer from the viewpoint of transportability.

(Support) As the support, a plastic sheet, a metal sheet, a glass sheet, a resin-coated paper,
Examples include ordinary sheet-shaped substrates such as paper and various composites. Examples of plastic sheets include polyethylene terephthalate sheets, polycarbonate sheets, polyethylene sheets, polyvinyl chloride sheets, polyvinylidene chloride sheets, polystyrene sheets, styrene-acrylonitrile sheets, polyester sheets and the like. Further, as the paper, actual printing paper, coated paper or the like can be used.

It is preferable that the support has minute voids (voids) because the image quality can be improved. Such a support may be, for example, a mixed melt obtained by mixing a thermoplastic resin and a filler composed of an inorganic pigment or a polymer incompatible with the thermoplastic resin into a single layer or a multi-layer by a melt extruder. It can be produced by forming a film and then stretching it monoaxially or biaxially. In this case, the porosity is determined by the selection of the resin and the filler, the mixing ratio, the stretching conditions and the like.

As the thermoplastic resin, polyolefin resin such as polypropylene and polyethylene terephthalate resin are preferable because they have good crystallinity, good stretchability and easy formation of voids. It is preferable to use the above-mentioned polyolefin resin or polyethylene terephthalate resin as a main component, and to appropriately use a small amount of another thermoplastic resin together. The inorganic pigment used as the filler preferably has an average particle size of 1 to 20 μm, and calcium carbonate, clay, diatomaceous earth, titanium oxide, aluminum hydroxide, silica or the like can be used. Further, as the incompatible resin used as the filler, when polypropylene is used as the thermoplastic resin, it is preferable to combine polyethylene terephthalate as the filler. Details of the support having minute voids (voids) are described in JP-A-2001-105752. The content of the filler such as the inorganic pigment in the support is 2 to 2 by volume.
About 30% is general.

The thickness of the support of the image receiving sheet is usually from 10 to 10.
It is 400 μm, 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 the adhesion with the image receiving layer (or cushion layer) or the adhesion with the image forming layer of the thermal transfer sheet. May be.

(Image Receiving Layer) In order to transfer and fix the image forming layer on the surface of the image receiving sheet, one or more image receiving layers are preferably provided on the support. The image receiving layer is preferably a layer formed mainly of an organic polymer binder. The binder is preferably a thermoplastic resin, examples of which include acrylic acid, methacrylic acid,
Homopolymers and copolymers of acrylic monomers such as acrylic acid esters and methacrylic acid esters, cellulosic polymers such as methyl cellulose, ethyl cellulose and cellulose acetate, polystyrene, polyvinyl pyrrolidone, polyvinyl butyral, polyvinyl alcohol, polyvinyl chloride, etc. Examples thereof include homopolymers and copolymers of vinyl monomers, condensation polymers such as polyesters and polyamides, and rubber polymers such as butadiene-styrene copolymers.
The binder of the image receiving layer is preferably a polymer having a glass transition temperature (Tg) of lower than 90 ° C. in order to obtain a proper adhesive force with the image forming layer. For this reason, it is possible to add a plasticizer to the image receiving layer. Further, the binder polymer preferably has a Tg of 30 ° C. or higher in order to prevent blocking between the sheets. The binder polymer of the image-receiving layer is the same as the binder polymer of the image-forming layer in that it improves the adhesion to the image-forming layer during laser recording and improves the sensitivity and image strength.
Alternatively, it is particularly preferable to use a similar polymer.

Smoother value of the image receiving layer surface is 23 ° C, 55% R
It is preferable that H is 0.5 to 50 mmHg (≈0.0665 to 6.65 kPa), and Ra is preferably 0.05 to 0.4 μm, which makes it possible for the image receiving layer and the image forming layer to not come into contact with the contact surface. Can reduce the micro voids in the transfer,
Furthermore, it is preferable in terms of image quality. The Ra value can be measured based on JIS B0601 using a surface roughness measuring device (Surfcom, manufactured by Tokyo Seiki Co., Ltd.) or the like. After charging the image receiving sheet according to US Federal Test Standard 4046, the charged potential of the image receiving layer 1 second after the image receiving sheet is grounded is preferably -100 to 100V. The surface resistance of the image receiving layer is preferably 10 ⁹ Ω or less at 23 ° C. and 55% RH. The coefficient of static friction on the surface of the image receiving layer is preferably 0.2 or less. The surface energy of the image receiving layer surface is preferably 23 to 35 mg / m ² .

When an image is once formed on the image receiving layer and then retransferred to a printing paper or the like, it is also preferable to form at least one of the image receiving layers from a photocurable material. Examples of the composition of such a photocurable material include a) a photopolymerizable monomer composed of at least one of a polyfunctional vinyl or vinylidene compound capable of forming a photopolymer by addition polymerization,
Examples thereof include a combination of b) an organic polymer, c) a photopolymerization initiator, and, if necessary, an additive such as a thermal polymerization inhibitor. As the above polyfunctional vinyl monomer,
Unsaturated esters of polyols, especially esters of acrylic acid or methacrylic acid (eg ethylene glycol diacrylate, pentaerythritol tetraacrylate) are used.

Examples of the organic polymer include the image forming layer forming polymer. As the photopolymerization initiator, a general photoradical polymerization initiator such as benzophenone or Michler's ketone is used in a proportion of 0.1 to 20% by mass in the layer.

The thickness of the image receiving layer is 0.3 to 7 μm, preferably 0.7 to 4 μm. When the thickness is less than 0.3 μm, the film strength is insufficient and the film is apt to be torn when retransferred to printing paper. If it is too thick, the gloss of the image after retransfer of the paper is increased and the approximation to the printed matter is reduced.

(Other Layers) Between the support and the image receiving layer,
A cushion layer may be provided. When the cushion layer is provided, the adhesion between the image forming layer and the image receiving layer at the time of laser thermal transfer can be improved and the image quality can be improved. Further, at the time of recording, even if foreign matter is mixed between the thermal transfer sheet and the image receiving sheet, the deformation effect of the cushion layer reduces the gap between the image receiving layer and the image forming layer, resulting in a reduction in the size of image defects such as white spots. You can also do it. Furthermore, when an image is transferred and formed 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 the transferability of the image receiving layer can be improved, and the transferred image can also be transferred. By reducing the gloss of the product, the closeness to the printed product can be improved.

The cushion layer is constructed so as to be easily deformed when a stress is applied to the image receiving layer, and in order to achieve the above effect, a material having a low elastic modulus, a material having rubber elasticity, or easily softened by heating. Preferably, it is made of a thermoplastic resin. The elastic modulus of the cushion layer at room temperature is preferably 0.5 MPa to 1.0 GPa, particularly preferably 1 MPa to 0.5 GPa, more preferably 10 to 100.
It is MPa. In addition, in order to insert foreign matter such as dust, the penetration (25
C., 100 g, 5 seconds) is preferably 10 or more. The cushion layer has a glass transition temperature of 80 ° C or lower, preferably 25 ° C or lower, and a softening point of 50 to 200 ° C. It is also possible to suitably add a plasticizer to the binder in order to adjust these physical properties, for example, Tg.

Specific materials used as the binder of the cushion layer include rubbers such as urethane rubber, butadiene rubber, nitrile rubber, acrylic rubber and natural rubber, as well as polyethylene, polypropylene, polyester and styrene-butadiene copolymer. Examples thereof include polymer, ethylene-vinyl acetate copolymer, ethylene-acrylic copolymer, vinyl chloride-vinyl acetate copolymer, vinylidene chloride resin, plasticizer-containing vinyl chloride resin, polyamide resin, and phenol resin. The thickness of the cushion layer varies depending on the resin used and other conditions, but is usually 3 to 100 μm,
It is preferably 10 to 52 μm.

The image receiving layer and the cushion layer need to be adhered to each other until the laser recording stage, but it is preferable that the image receiving layer and the cushion layer are provided so as to be peelable in order to transfer the image to the printing paper. In order to facilitate peeling, it is also preferable to provide a peeling layer having 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 becomes difficult to appear, so it is necessary to adjust the type according to the type of the release layer. Specific examples of the binder for the release layer include polyolefin, polyester, polyvinyl acetal, polyvinyl formal, polyparabanic acid, polymethyl methacrylate, polycarbonate, ethyl cellulose, nitrocellulose, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, polyvinyl chloride. , Urethane resin,
Fluorine-based resins, polystyrene, styrenes such as acrylonitrile styrene and those obtained by crosslinking these resins, polyamides, polyimides, polyetherimides, polysulfones, polyethersulfones, aramids, etc., Tg of 65 ° C.
The above-mentioned thermosetting resins and cured products of these resins can be mentioned. As the curing agent, general curing agents such as isocyanate and melamine can be used.

When a binder for the release layer is selected according to the above physical properties, polycarbonate, acetal, and ethyl cellulose are preferable from the viewpoint of storability. Further, when an acrylic resin is used for the image receiving layer, release is performed when retransferring the image after laser thermal transfer. Since it has good properties, it is particularly preferable. In addition, separately, a layer having extremely low adhesiveness to the image receiving layer upon cooling can be used as the release layer. Specifically, a layer containing a heat-melting compound such as waxes and binders or a thermoplastic resin as a main component can be used. Examples of the heat-meltable compound include the substances described in JP-A-63-193886. In particular, microcrystalline wax, paraffin wax, carnauba wax and the like are preferably used. As the thermoplastic resin, ethylene-based copolymers such as ethylene-vinyl acetate-based resin and cellulose-based resin are preferably used.

If desired, higher fatty acids, higher alcohols, higher fatty acid esters, amides, higher amines and the like can be added to the release layer as additives.
Another structure of the peeling layer is a layer having peelability by cohesively breaking itself by melting or softening during heating. Such a release layer preferably contains a supercooling substance. Examples of the supercooling substance include poly-ε-caprolactone, polyoxyethylene, benzotriazole, tribenzylamine, vanillin and the like. Further, in the peelable layer having another structure, a compound that reduces the adhesion to the image receiving layer is included. Examples of such compounds include silicone resins such as silicone oil; fluorine resins such as Teflon (registered trademark) and fluorine-containing acrylic resins; polysiloxane resins; acetal resins such as polyvinyl butyral, polyvinyl acetal and polyvinyl formal; polyethylene. Solid waxes such as wax and amide wax; fluorine-based and phosphoric acid ester-based surfactants and the like can be mentioned. As a method of forming the release layer,
A blade coater, a roll coater, a bar coater, which is obtained by dissolving the material in a solvent or dispersing it in a latex form.
A coating method using a curtain coater, a gravure coater, or the like, an extrusion lamination method using hot melt, or the like can be applied, and it can be formed by coating on the cushion layer. Alternatively, there is a method in which a material obtained by dissolving the raw material in a solvent or dispersed in the form of a latex on a temporary base is applied by the above-mentioned method and the cushion layer is bonded and then the temporary base is peeled off.

The image-receiving sheet combined with the thermal transfer sheet may have a structure in which the image-receiving layer also serves as a cushion layer. In that case, the image-receiving sheet is a support / cushionable image-receiving layer or a support / undercoat layer. / It may have a cushioning image-receiving layer. Also in this case, it is preferable that the cushioning image-receiving layer is detachably provided so that the image can be retransferred to the actual printing paper. In this case, the image after retransfer to the actual printing paper has excellent gloss. The thickness of the cushioning image-receiving layer is 5 to 100 μm, preferably 10
Is about 40 μm.

It is preferable to provide a back layer on the surface of the image receiving sheet opposite to the surface on which the image receiving layer of the support is provided, since the transportability of the image receiving sheet is improved. It is preferable to add an antistatic agent such as a surfactant or tin oxide fine particles, and a matting agent such as silicon oxide or PMMA particles to the back layer in order to improve transportability in the recording apparatus. The above additives can be added not only to the back layer but also to the image receiving layer and other layers, if necessary. Although it is not possible to specify the type of additive depending on its purpose,
For example, in the case of a matting agent, particles having an average particle size of 0.5 to 10 μm can be added to the layer in an amount of about 0.5 to 80%. As the antistatic agent, the surface resistance of the layer is 23 ° C., 50
% 10 ¹² Omega less RH for, more preferably 10 ⁹ Omega
As described below, various surfactants and conductive agents can be appropriately selected and used.

As the binder used in the back layer, gelatin, polyvinyl alcohol, methyl cellulose, nitrocellulose, acetyl cellulose, aromatic polyamide resin, silicone resin, epoxy resin, alkyd resin, phenol resin, melamine resin, fluorine resin, polyimide resin. , Urethane resin, acrylic resin, urethane modified silicone resin, polyethylene resin, polypropylene resin, polyester resin, Teflon resin, polyvinyl butyral resin, vinyl chloride resin, polyvinyl acetate, polycarbonate, organic boron compound, aromatic ester, fluorinated polyurethane A general-purpose polymer such as polyethersulfone can be used. The use of a crosslinkable water-soluble binder as the binder of the back layer, which is effective in preventing the matting agent from falling off and improving the scratch resistance of the back layer. It is also effective in blocking during storage. This cross-linking means can employ any one or combination of heat, actinic rays, and pressure depending on the properties of the cross-linking agent used without particular limitation. In some cases, an optional adhesive layer may be provided on the side of the support on which the back layer is provided in order to impart adhesiveness to the support.

As the matting agent preferably added to the back layer, organic or inorganic fine particles can be used. As an organic matting agent, polymethylmethacrylate (PMM
A), polystyrene, polyethylene, polypropylene,
Examples thereof include fine particles of other radical polymerization type polymers, fine particles of condensation polymers such as polyester and polycarbonate. The back layer is preferably provided in an amount of about 0.5 to 5 g / m ² . If it is less than 0.5 g / m ² , the coating property is unstable and problems such as powder drop of the matting agent are likely to occur.
Further, when it is applied over 5 g / m ² , the particle size of a suitable matting agent becomes very large, and the back layer causes the embossing of the image receiving layer surface, especially the thermal transfer for transferring a thin image forming layer. In this case, the recorded image is likely to be missing or uneven. The matting agent preferably has a number average particle size larger by 2.5 to 20 μm than the layer thickness of only the binder of the back layer. Among the matting agents, particles having a particle size of 8 μm or more need to be 5 mg / m ² or more, and preferably 6 to 600 mg /
m ² . This improves especially foreign matter failures.
Also, the value obtained by dividing the standard deviation of the particle size distribution by the number average particle size σ / r
By using a narrow particle size distribution such that n (= coefficient of variation of particle size distribution) is 0.3 or less, defects caused by particles having an abnormally large particle size can be improved.
The desired performance is obtained with a smaller addition amount. More preferably, this coefficient of variation is 0.15 or less.

An antistatic agent is preferably added to the back layer in order to prevent foreign matters from adhering to the back layer due to frictional charging with the transport roll. Examples of the antistatic agent include cationic surfactants, anionic surfactants, nonionic surfactants, polymeric antistatic agents, conductive fine particles, and "1129".
Compounds described in “Chemical products of No. 0”, Kagaku Kogyo Nipposha, pp. 875-876, etc. are widely used. Among the above substances, metal oxides such as carbon black, zinc oxide, titanium oxide and tin oxide, and conductive fine particles such as organic semiconductors are preferably used as the antistatic agent that can be used in the back layer. It is particularly preferable to use the conductive fine particles because the antistatic agent is not dissociated from the back layer and a stable antistatic effect is obtained regardless of the environment. In addition, various activators are added to the back layer in order to impart coatability and releasability.
It is also possible to add a release agent such as silicone oil or fluorine resin. The back layer is particularly preferable when the softening point of the cushion layer and the image receiving layer measured by TMA (Thermomechanical Analysis) is 70 ° C. or lower.

The TMA softening point is determined by observing the phase of the object to be measured while raising the temperature of the object to be measured at a constant rate of temperature and applying a constant load. In the present invention, the temperature at which the phase of the measurement object begins to change is defined as the TMA softening point. The measurement of the softening point by TMA can be performed using a device such as Thermoflex manufactured by Rigaku Denki Co., Ltd.

The thermal transfer sheet and the image receiving sheet can be used for image formation as a laminate in which the image forming layer of the thermal transfer sheet and the image receiving layer of the image receiving sheet are laminated. The laminate of the thermal transfer sheet and the image receiving sheet can be formed by various methods. For example, it can be easily obtained by stacking the image forming layer of the thermal transfer sheet and the image receiving layer of the image receiving sheet, and 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 laminated body, the above-mentioned vacuum adhesion method is also suitably used. In the vacuum contact method, the image receiving sheet is first wound on the drum provided with suction holes for vacuuming, and then a thermal transfer sheet having a size slightly larger than that of the image receiving sheet is pressed while the air is uniformly pushed out by the squeeze roller. It is a method of vacuum adhesion to. As another method, there is also a method in which an image receiving sheet is mechanically attached while being pulled on a metal drum, and a thermal transfer sheet is similarly mechanically pulled and attached so as to be in close contact therewith. Among these methods, the vacuum contact method is particularly preferable because it does not require temperature control of a heat roller or the like and facilitates quick and uniform lamination.

[0121]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.
In the text, "part" means "part by mass" unless otherwise specified.

Example 1-Preparation of Thermal Transfer Sheet K (Black)-[Formation of Back Layer] [Preparation of Back Layer 1 Coating Solution] 2 parts of an acrylic resin aqueous dispersion (Jurimer ET410, solid content 20% by mass, Nippon Pure Chemical Industries, Ltd.) Antistatic agent (tin oxide-antimony oxide aqueous dispersion) 7.0 parts (average particle size: 0.1 μm, 17 mass%) polyoxyethylene phenyl ether 0.1 part melamine compound 0.3 parts (Sumithix Resin M-3, manufactured by Sumitomo Chemical Co., Ltd.) Distilled water Prepared so that the total amount becomes 100 parts [Formation of back first layer] Biaxially stretched polyethylene terephthalate support having a thickness of 75 μm Body (Ra on both sides is 0.01μ
m) Corona treatment is applied to one side (back side) of
After applying one layer coating solution to a dry layer thickness of 0.03 μm
It was dried at 180 ° C. for 30 seconds to form a back first layer. Young's modulus in the longitudinal direction of the support is 450 Kg / mm ² (≈4.
4 GPa), Young's modulus in the width direction is 500 kg / mm ²
(≈4.9 GPa). F-5 in the longitudinal direction of the support
^{Value, 10Kg / mm 2 (≒ 98MPa} ), F-5 value of the support width direction, 13Kg / mm ² (≒ 127.4MP
The heat shrinkage rate of the support at 100 ° C. for 30 minutes is 0.3% in the longitudinal direction and 0.1% in the width direction. Breaking strength is 20 Kg / mm ² (≈196 MPa) in the longitudinal direction
Then, the width direction is 25 Kg / mm ² (≈245 MPa), and the elastic modulus is 400 Kg / mm ² (≈3.9 GPa).

[Preparation of Coating Solution for Back Second Layer] 3.0 parts of polyolefin (Chemipearl S-120, 27 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, Nissan Chemical Co., Ltd.) Epoxy compound 0.3 parts (Dinacol EX- 614B, manufactured by Nagase Kasei Co., Ltd.) Distilled water Prepared so that the total amount is 100 parts. [Formation of back second layer] Back second layer is applied to back second layer coating solution to a dry layer thickness of 0.03 μm. 170 ℃ after applying
And dried for 30 seconds to form a back second layer.

1) Preparation of coating liquid for photothermal conversion layer Mix the following components while stirring with a stirrer, and
A coating solution for the heat conversion layer was prepared. [Composition of coating liquid for photothermal conversion layer] ・ Infrared absorbing dye 10 parts ("NK-2919", manufactured by Hayashibara Biochemical Research Institute,
Cyanine color having a structure represented by the general formula (A)
Elementary (in the general formula (A), Z is a naphthalene ring, T is -CH₂
-, L is = CH-CH = CH-CH = CH-, and M is
-(CH₂) _Four-, X is NH_Four) ・ 4 parts of polyimide resin with the following structure (“Ricacoat SN20”, manufactured by Shin Nippon Rika Co., Ltd., thermal decomposition temperature: 510 ° C.)

[0125]

[Chemical 5]

(In the formula, R ₁ represents SO _2. R ₂ represents

[0127]

[Chemical 6]

Is shown. ) ・ N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation) 1900 parts ・ Methyl ethyl ketone 300 parts ・ 2 parts of matting agent (Seahoster KEP150, manufactured by Nippon Shokubai Co., Ltd.) ・ Surfactant 1 part   ("Megafuck F176p", manufactured by Dainippon Ink and Chemicals, Inc.)

2) Formation of a photothermal conversion layer on the surface of a support After coating the above coating solution for a photothermal conversion layer with a wire bar on one surface of a polyethylene terephthalate film (support) having a thickness of 75 μm, Apply the coating at 120 ℃
And dried in the oven for 2 minutes to form a photothermal conversion layer on the support. The optical density of the obtained photothermal conversion layer at a wavelength of 808 nm was measured by a Shimadzu UV-spectrophotometer UV-24.
When measured at 0, the OD was 1.03. The layer thickness was 0.3 μm on average when the cross section of the photothermal conversion layer was observed with a scanning electron microscope.

3) Preparation of Coating Solution for Black Image-Forming Layer The following components were put in a kneader mill, and a shearing force was applied while adding a small amount of solvent to carry out a dispersion pretreatment. A solvent was further added to the dispersion to finally prepare the following composition, and the mixture was subjected to sand mill dispersion for 2 hours to obtain a pigment dispersion mother liquor. [Black pigment dispersion mother liquor composition] Composition 1 • Polyvinyl butyral 12.6 parts (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.) • Pigment Black (Pigment Black) 7 (carbon black C.I. 77266) 4.5 parts ("Mitsubishi Carbon Black # 5", manufactured by Mitsubishi Chemical Co., Ltd., PVC blackness: 1) -Dispersion aid 0.8 parts ("Solspers S-20000", manufactured by ICI Co., Ltd.) -N-Propyl alcohol 79.4 parts Composition 2-Polyvinyl butyral 12.6 parts ("S-REC B BL-SH", Sekisui Chemical Co., Ltd.)-Pigment Black (Pigment Black) 7 (carbon black C.I. No. 77266) 10.5 parts ("Mitsubishi Carbon Black MA100", manufactured by Mitsubishi Chemical Corporation, PVC blackness: 0) Dispersion aid 0.8 parts ( "SOLSPERSE S-20000", ICI (Ltd.)) - n-propyl alcohol 79.4 parts

Next, the following components were mixed with stirring with a stirrer to prepare a coating liquid for black image forming layer. [Composition of coating liquid for black image-forming layer] -Black pigment dispersion mother liquor 185.7 parts Composition 1: Composition 2 = 70:30 (parts) -Polyvinyl butyral 11.9 parts ("S-REC B BL-SH", Sekisui Chemical Co., Ltd.) Kogyo Co., Ltd.-Wax compound (stearic acid amide "Nutron 2", manufactured by Nippon Seika Co., Ltd.) 1.7 parts (behenic acid amide "Diamid BM", manufactured by Nippon Kasei Co., Ltd.) 1 0.7 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 (erucic acid amide " Diamid L-200 ", manufactured by Nippon Kasei Co., Ltd. 1.7 parts (oleic acid amide" Diamid O-200 ", manufactured by Nippon Kasei Co., Ltd.) 1.7 parts, rosin 11.4 parts (" KE -311 ”, Arakawa Chemical ( (Components: Resin acid 80-97%; Resin acid component: Abietic acid 30-40%, Neoabietic acid 10-20%, Dihydroabietic acid 14%, Tetrahydroabietic acid 14%) ・ Surfactant 2 .1 part ("Megafuck F-176PF", solid content 20%, manufactured by Dainippon Ink and Chemicals, Inc.)-Inorganic pigment 7.1 parts ("MEK-ST", 30% methyl ethyl ketone solution, Nissan Chemical Co., Ltd.) -N-propyl alcohol 1050 parts-Methyl ethyl ketone 295 parts Particles in the obtained black image-forming layer coating solution were measured using a laser scattering type particle size distribution measuring device, and found to have an average particle size of 0.25 μm. Yes, the proportion of particles of 1 μm or larger was 0.5%.

4) Formation of Black Image Forming Layer on Photothermal Conversion Layer Surface The coating solution for black image forming layer was applied on the surface of the photothermal converting layer for 1 minute by using a wire bar, and then the coated product was heated to 100 ° C. And dried in an oven for 2 minutes to form a black image forming layer on the photothermal conversion layer. Through the above steps, a thermal transfer sheet in which a photothermal conversion layer and a black image forming layer are provided in this order on the support (hereinafter referred to as a thermal transfer sheet K. Similarly, a yellow image forming layer and an image forming layer are also provided. A thermal transfer sheet Y was prepared, a sheet provided with a magenta image forming layer was referred to as a thermal transfer sheet M, and a sheet provided with a cyan image forming layer was referred to as a thermal transfer sheet C). The transmission density (transmission optical density) of the black image forming layer of the thermal transfer sheet K was measured by a Macbeth densitometer "TD-904".
It was 0.91 when measured with (W filter). Further, the layer thickness of the black image forming layer was measured and found to be 0.60 μm on average.

The physical properties of the obtained image forming layer were as follows. The surface hardness of the image forming layer is 10g with a sapphire needle.
The above is preferable, and specifically, it was 200 g or more. The smoother value of the surface is 0.5 to 50 mmHg at 23 ° C and 55% RH (≒
0.0665 to 6.65 kPa) is preferable, specifically 9.3 m
It was mHg (≈1.24 kPa). The coefficient of static friction on the surface is preferably 0.2 or less, and specifically 0.08.

—Preparation of Thermal Transfer Sheet Y— Preparation of thermal transfer sheet K, except that in the preparation of thermal transfer sheet K, a yellow image forming layer coating solution having the following composition was used in place of the black image forming layer coating solution. A thermal transfer sheet Y was produced in the same manner as. The layer thickness of the image forming layer of the obtained thermal transfer sheet Y was 0.42 μm. [Yellow Pigment Dispersion Mother Liquor Composition] Yellow pigment composition 1: -Polyvinyl butyral 7.1 parts ("S-REC B BL-SH", manufactured by Sekisui Chemical Co., Ltd.)-Pigment Yellow (Pigment Yellow) 180 (CINN) o.21290) 12.9 parts ("Novoperm Yellow (Novopalm Yellow) P-HG", manufactured by Clariant Japan Co., Ltd.) ・ Dispersion aid 0.6 parts ("Solspers S-20000", manufactured by ICI Co., Ltd.) ) -N-Propyl alcohol 79.4 parts [Yellow pigment dispersion mother liquor composition] Yellow pigment composition 2: -Polyvinyl butyral 7.1 parts ("S-REC B BL1-SH", Sekisui Chemical Co., Ltd.)-Pigment Yellow ( Pigment Yellow) 139 (CINNO 56298) 12.9 parts (" Ovoperm Yellow (Novo palm yellow) M2R 70 ", manufactured by Clariant Japan Co., Ltd.) Dispersion aid 0.6 parts (" SOLSPERSE S-20000 ", ICI Co., Ltd.) n-propyl alcohol 79.4 parts

[0135] [Coating liquid composition for yellow image forming layer] -126 parts of the above yellow pigment dispersion mother liquor     Yellow pigment composition 1: Yellow pigment composition 2 = 95: 5 (parts) ・ Polyvinyl butyral 4.6 parts ("S-REC B BL-SH", Sekisui Chemical Co., Ltd.) ・ Wax compounds (Stearic acid amide "Nutron 2", manufactured by Nippon Seika Co., Ltd.) 0.7 parts (Behenamide “Diamid BM”, manufactured by Nippon Kasei Co., Ltd.) 0.7 parts (Lauric acid amide "Diamid Y", manufactured by Nippon Kasei Co., Ltd.) 0.7 parts (Palmitic acid amide "Diamit KP", manufactured by Nippon Kasei Co., Ltd.) 0.7 parts (Eruca acid amide "Diamid L-200", manufactured by Nippon Kasei Co., Ltd.) 0.7 parts (Oleic acid amide "Diamid O-200", manufactured by Nippon Kasei Co., Ltd.) 0.7 parts ・ Nonionic surfactant 0.4 parts ("Chemist 1100", Sanyo Kasei Co., Ltd.) ・ Rosin 2.4 parts ("KE-311", manufactured by Arakawa Chemical Co., Ltd.)   (Ingredient: Resin acid 80-97%; Resin acid component: Abietic acid 30-40%, Neoabieti Acid 10-20%, dihydroabietic acid 14%, tetrahydroabietic acid 14%) ・ Surfactant 0.8 parts ("Megafuck F-176PF", solid content 20%, manufactured by Dainippon Ink and Chemicals, Inc. ) ・ N-propyl alcohol 793 parts ・ Methyl ethyl ketone 198 parts

The physical properties of the obtained image forming layer were as follows. The surface hardness of the image forming layer is 10g with a sapphire needle.
The above is preferable, and specifically, it was 200 g or more. The smoother value of the surface is 0.5 to 50 mmHg at 23 ° C and 55% RH (≒
0.0665 to 6.65 kPa) is preferred, specifically 2.3 m
It was mHg (≈0.31 kPa). The coefficient of static friction on the surface is preferably 0.2 or less, and specifically 0.1.

—Preparation of Thermal Transfer Sheet M— Preparation of thermal transfer sheet K except that a magenta image forming layer coating solution having the following composition was used in place of the black image forming layer coating solution in the preparation of the thermal transfer sheet K. A thermal transfer sheet M was produced in the same manner as. The image forming layer of the resulting thermal transfer sheet M had a layer thickness of 0.38 μm. [Magenta Pigment Dispersion Mother Liquor] Magenta Pigment Composition 1; -Polyvinyl butyral 12.6 parts ("Denka Butyral # 2000-L", manufactured by Denki Kagaku Kogyo KK, Vicat softening point 57 ° C) -Pigment Red (Pigment Red) 57: 1 (C.I. No. 1 5850: 1) 15.0 parts ("Symuller Brilliant Carmine 6B-229", manufactured by Dainippon Ink and Chemicals, Inc.)-Dispersion aid 0. 6 parts ("Solspers S-20000", manufactured by ICI Co., Ltd.)-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., Vicat softening point 57 ° C) ment Red (Pigment Red) 57: 1 (CI. No. 1 5850: 1) 15.0 parts (“Lionol Red (Rionol Red) 6B-4290G”, manufactured by Toyo Ink Mfg. Co., Ltd.) Agent 0.6 parts ("Solspers S-20000", manufactured by ICI Corporation) -n-Propyl alcohol 79.4 parts

[0138] [Coating liquid composition for magenta image forming layer] 163 parts of the above-mentioned magenta pigment dispersion mother liquor     Magenta pigment composition 1: Magenta pigment composition 2 = 95: 5 (part) ・ Polyvinyl butyral 4.0 parts ("Denka Butyral # 2000-L", manufactured by Denki Kagaku Kogyo Co., Ltd., Vicat softening 57 ° C) ・ Wax compounds (Stearic acid amide "Nutron 2", manufactured by Nippon Seika Co., Ltd.) 1.0 part (Behenamide “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 (Eruca acid amide "Diamind 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 ・ Nonionic surfactant 0.7 parts ("Chemist 1100", Sanyo Kasei Co., Ltd.)  ・ Rosin 4.6 parts ("KE-311", manufactured by Arakawa Chemical Co., Ltd.)   (Ingredients: Resin acid 80-97%; Resin acid component abietic acid 30-40%, Neoabietin Acid 10-20% Dihydroabietic acid 14%, Tetrahydroabietic acid 14%) ・ Pentaerythritol tetraacrylate 2.5 parts (“NK Ester A-TMMT”, manufactured by Shin Nakamura Chemical Co., Ltd.) ・ Surfactant 1.3 parts ("Megafuck F-176PF", solid content 20%, manufactured by Dainippon Ink and Chemicals, Inc. ) ・ N-propyl alcohol 848 parts ・ Methyl ethyl ketone 246 parts

The physical properties of the obtained image forming layer were as follows. The surface hardness of the image forming layer is 10g with a sapphire needle.
The above is preferable, and specifically, it was 200 g or more. The smoother value of the surface is 0.5 to 50 mmHg at 23 ° C and 55% RH (≒
0.0665 to 6.65 kPa) is preferred, specifically 3.5 m
It was mHg (≈0.47 kPa). The coefficient of static friction on the surface is preferably 0.2 or less, and specifically 0.08.

—Preparation of Thermal Transfer Sheet C— Preparation of thermal transfer sheet K, except that a cyan image forming layer coating solution having the following composition was used in place of the black image forming layer coating solution in the preparation of thermal transfer sheet K. A thermal transfer sheet C was produced in the same manner as. The layer thickness of the image forming layer of the obtained thermal transfer sheet C was 0.45 μm. [Cyan Pigment Dispersion Mother Liquor] Cyan Pigment Composition 1: • Polyvinyl butyral 12.6 parts (“S-REC B BL-SH”, Sekisui Chemical Co., Ltd.) • Pigment Blue 15: 4 (CI) No. 74160) 15.0 parts ("Cyanine Blue (Cyanine Blue) 700-10FG", manufactured by Toyo Ink Mfg. Co., Ltd.)-Dispersion aid 0.8 parts ("PW-36", Kusumoto Kasei Co., Ltd.) N-Propyl alcohol 110 parts [Cyan pigment dispersion mother liquor composition] Cyan pigment composition 2: • Polyvinyl butyral 12.6 parts (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.) • Pigment Blue (Pigment) Blue) 15 (C.I. No. 74 160) 15.0 parts ("Lionol Blue (Lionol Blue 7027 ", manufactured by Toyo Ink Mfg Co., Ltd.) Dispersion aid 0.8 parts (" PW-36 ", manufactured by Kusumoto Chemicals Ltd.) n-propyl alcohol 110 parts

[0141] [Coating liquid composition for cyan image forming layer] 118 parts of the above mother pigment dispersion of cyan pigment     Cyan pigment composition 1: Cyan pigment composition 2 = 90: 10 (parts) ・ Polyvinyl butyral 5.2 parts ("ESREC B BL-SH", Sekisui Chemical Co., Ltd.) ・ Inorganic pigment "MEK-ST" 1.3 parts ・ Wax compounds (Stearic acid amide "Nutron 2", manufactured by Nippon Seika Co., Ltd.) 1.0 part (Behenamide “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 "Diamined KP", manufactured by Nippon Kasei Co., Ltd.) 1.0 part (Eruca 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.)   (Ingredient: Resin acid 80-97%; Resin acid component: Abietic acid 30-40%, Neoabieti Acid 10-20%, dihydroabietic acid 14%, tetrahydroabietic acid 14%) -Pentaerythritol tetraacrylate 1.7 parts (“NK Ester A-TMMT”, manufactured by Shin Nakamura Chemical Co., Ltd.) ・ Surfactant 1.7 parts ("Megafuck F-176PF", solid content 20%, manufactured by Dainippon Ink and Chemicals, Inc. ) ・ N-Propyl alcohol 890 parts ・ Methyl ethyl ketone 247 parts

The physical properties of the obtained image forming layer were as follows. The surface hardness of the image forming layer is 10g with a sapphire needle.
The above is preferable, and specifically, it was 200 g or more. The smoother value of the surface is 0.5 to 50 mmHg at 23 ° C and 55% RH (≒
0.0665 to 6.65 kPa) is preferred, specifically 7.0 m
It was mHg (≈ 0.93 kPa). The coefficient of static friction on the surface is preferably 0.2 or less, and specifically 0.08.

Example 2 In Example 1, the polyimide resin of the coating solution for the photothermal conversion layer was changed to polyamideimide resin (Vylomax HR11N).
N, manufactured by Toyobo Co., Ltd., except that Example 1 was used.
A thermal transfer sheet was prepared in the same manner as in.

Comparative Example 1 In Example 1, the infrared absorbing dye of the coating solution for the photothermal conversion layer was a cyanine dye having a structure represented by the following general formula (B) (NK-2014, Hayashibara Biochemical Research Co., Ltd.). A thermal transfer sheet was produced in the same manner as in Example 1 except that the thermal transfer sheet was replaced with the one made from. General formula (B)

[0145]

[Chemical 7]

(In the formula, R represents CH ₃ and X ⁻ represents ClO ₄ ^— .)

Comparative Example 2 In Example 2, the cyanine dye having the structure represented by the above general formula (B) was used as the infrared absorbing dye of the coating solution for the photothermal conversion layer (NK-2014, Hayashibara Biochemical Research Laboratory Co., Ltd.). A thermal transfer sheet was prepared in the same manner as in Example 2 except that the thermal transfer sheet was replaced with the one manufactured in the above.

—Preparation of Image Receiving Sheet— A cushion layer coating solution and an image receiving layer coating solution having the following compositions were prepared. 1) Cushion layer coating liquid-Vinyl chloride-vinyl acetate copolymer 20 parts (main binder) ("MPR-TSL", manufactured by Nissin Chemical Co., Ltd.)-Plasticizer 10 parts ("Parplex G-40 , CP.HALL.COMPANY Co., Ltd.-Surfactant (fluorine-based: coating aid) 0.5 part ("Megafuck F-177", Dainippon Ink and Chemicals, Inc.)-Antistatic agent ( Quaternary ammonium salt) 0.3 parts ("SAT-5 Super (IC)", manufactured by Nippon Pure Chemical Industries, Ltd.)-Methyl ethyl ketone 60 parts-Toluene 10 parts-N, N-dimethylformamide 3 parts

[0149] 2) Coating liquid for image receiving layer ・ Polyvinyl butyral 8 parts ("ESREC B BL-SH", Sekisui Chemical Co., Ltd.) ・ Antistatic agent 0.7 parts ("Sunstat 2012A", manufactured by Sanyo Kasei Co., Ltd.) ・ Surfactant 0.1 parts ("Megafuck F-177", manufactured by Dainippon Ink and Chemicals, Inc.) ・ 20 parts of n-propyl alcohol ・ Methanol 20 parts ・ 1-Methoxy-2-propanol 50 parts

Using a narrow coater, a white PET support (“Lumirror # 130E58”, manufactured by Toray Industries, Inc., thickness 1)
30 μm), the above coating solution for forming a cushion layer is applied, the coating layer is dried, and then the image receiving layer coating solution is applied.
Dried. The thickness of the cushion layer after drying is about 20 μm,
The coating amount was adjusted so that the layer thickness of the image receiving layer was about 2 μm. The white PET support is a laminate of a void-containing polyethylene terephthalate layer (thickness: 116 μm, porosity: 20%) and a titanium oxide-containing polyethylene terephthalate layer (thickness: 7 μm, titanium oxide content: 2%) provided on both sides thereof. It is a void-containing plastic support consisting of (total thickness: 130 μm, specific gravity: 0.8). The produced material was wound in a roll form, stored at room temperature for 1 week, and then used for image recording with the following laser light. The physical properties of the obtained image receiving layer were as follows. Surface roughness Ra 0.4 to 0.01
μm was preferable, and specifically, it was 0.02 μm. The waviness of the surface of the image receiving layer is preferably 2 μm or less, and specifically 1.2 μm. The smoother value of the surface of the image receiving layer is 0.5 to 50 mmHg (≈0.0665 to 6.65 kP at 23 ° C and 55% RH).
a) is preferable, and specifically, 0.8 mmHg (≈0.11
kPa). Coefficient of static friction on the surface of the image receiving layer is 0.8
The following was preferable, and specifically it was 0.37.

-Formation of Transfer Image- The image-receiving sheet (56 cm x 7 cm) prepared above was placed on a rotary drum having a diameter of 1 cm and a 38 cm diameter rotary drum having a vacuum section hole (one areal density in an area of 3 cm x 8 cm).
(9 cm) was wound and vacuum-adsorbed. Then 61c
The thermal transfer sheet K (black) cut into m × 84 cm is stacked so as to be evenly protruded from the image receiving sheet,
While squeezing with a squeeze roller, the section holes were adhered and laminated so that air was sucked. The degree of pressure reduction when the section holes are closed is 1 atm.
It was 150 mmHg (≈81.13 kPa). The drum is rotated, and a semiconductor laser beam having a wavelength of 808 nm is condensed on the surface of the laminated body on the drum so as to form a spot of 7 μm on the surface of the photothermal conversion layer. Laser images (image lines) were recorded on the laminate while moving in a direction perpendicular to the scanning direction) (sub-scanning). The laser irradiation conditions are as follows. As the laser beam used in this example, a laser beam having a multi-beam two-dimensional array of parallelograms having five rows in the main scanning direction and three rows in the sub-scanning direction was used. Laser power 217 mJ / m ² environment temperature and humidity 23 ° C. 50% The diameter of the exposure drum is preferably 360 mm or more, and specifically, the one having a diameter of 380 mm was used. The image size is 5
The size is 15 mm × 728 mm, and the resolution is 2438 dpi. When the laminated body on which the laser recording was completed was removed from the drum and the thermal transfer sheet K was peeled off from the image receiving sheet by hand, only the light irradiation area of the image forming layer of the thermal transfer sheet K was transferred from the thermal transfer sheet K to the image receiving sheet. It was confirmed that it was done.

Similarly to the above, the thermal transfer sheet Y,
An image was transferred from the thermal transfer sheets M and C to the image receiving sheet. The transferred four-color image was further transferred to recording paper to form a multicolor image.
Even when laser recording was performed with high energy by the laser light having a three-dimensional array, it was possible to form a multicolor image with good image quality and stable transfer density. For the transfer to the paper, a thermal transfer device having a dynamic friction coefficient of 0.1 to 0.7 with respect to polyethylene terephthalate as a material of the insertion table and a conveying speed of 15 to 50 mm / sec was used. The Vickers hardness of the heat roll material of the thermal transfer device is preferably 10 to 100, and specifically, the Vickers hardness of 70 was used.

<Measurement of Reflection Spectrum> The transferred image recorded on the image receiving sheet was further transferred to Tokubishi Art Paper using a laminator (CA600T, manufactured by Fuji Photo Film Co., Ltd.), and then a spectrophotometer (UV2100, Shimadzu). The reflection spectrum was measured by using Seisakusho Co., Ltd. (after recording). Without irradiating laser light to record an image,
The image forming layer of each color was directly transferred to the image receiving sheet using the above laminator, then the image forming layer transferred to the image receiving sheet was transferred to Tokubishi art paper, and the reflection spectrum was measured in the same manner as above (recording Previous). Table 1 shows the reflectance (%) in the cyan color (460 nm) where the difference between the reflectances before and after recording is maximum in the visible light region.

<Measurement of Color Difference> For the chromaticity value before exposure, X-rite 938 (manufactured by X-rite Co.) was used after transferring the transfer image after image recording by irradiating laser light to Tokubishi art paper. It was measured using. The chromaticity value after light exposure was measured in the same manner as above after applying a light source of 30,000 Lux to the image transferred to the Tokubishi art paper until the chromaticity value did not change. Similar to the above, for the cyan color in which the color difference is remarkably exhibited, the color difference was calculated from the chromaticity value before the exposure and the chromaticity value after the exposure. The results are shown in Table 1 .

<Visual inspection> The image after image recording by irradiating laser light is transferred to Tokubishi art paper, and half of the image transferred to Tokubishi art paper is covered with a sheet that does not transmit light, After exposure to a light source of 30,000 Lux for 0.5 hours with half of the film exposed, it was visually observed whether the boundary between the sheet-covered portion and the exposed and exposed portion was visible. The results are shown in Table 1 by symbols (◯, ×). ○: I do not understand the boundary. X: The boundary is broken.

[0156]

[Table 1]

[0157]

According to the present invention, the hue of the transferred image formed on the image-receiving sheet is good, and the image quality is good, even when laser recording is carried out at high energy with the multi-beam laser light. Also, a multicolor image forming material having a stable transfer density is provided. By using the multicolor image forming material of the present invention, it is possible to provide a contract proof which is compatible with the filmless of the CTP era and replaces the proof and the analog type color proof. It can reproduce the color reproducibility that matches the analog color proof. The same pigment-based coloring material as the printing ink is used, transfer to the actual paper is possible, and a DDCP system without moire can be provided. In addition, it is possible to transfer this paper, uses the same pigment-based coloring material as the printing ink, and has a large size (A2 / B
2) A digital direct color proof system can be provided.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an outline of a mechanism of multicolor image formation by thin film thermal transfer using a laser.

FIG. 2 is a diagram showing a configuration example of a laser thermal transfer recording device.

[Explanation of symbols] 1 recording device 2 recording head 3 Sub-scanning rail 4 recording drum 5 Thermal transfer sheet loading unit 6 Image-receiving sheet roll 7 Conveyor rollers 8 squeeze roller 9 cutter 10 Thermal transfer sheet 10K, 10C, 10M, 10Y Thermal transfer sheet roll 12 Support 14 Photothermal conversion layer 16 Image forming layer 20 Image receiving sheet 22 Support for image receiving sheet 24 Image receiving layer 30 stacks 31 discharge stand 32 Waste port 33 outlet 34 air 35 waste box

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) B41M 5/26 Q

Claims (4)

[Claims] 1. An image receiving sheet having at least an image receiving layer on a support, and four or more types of thermal transfer sheets containing yellow, magenta, cyan, and black having at least a photothermal conversion layer and an image forming layer on the support. By using, the image forming layer of each thermal transfer sheet and the image receiving layer of the image receiving sheet are overlapped facing each other , laser light is irradiated, and the laser light irradiation region of the image forming layer is transferred onto the image receiving layer of the image receiving sheet. A multicolor image forming material for image recording, the reflectance of the image forming layer of the thermal transfer sheet before being irradiated with the laser beam and image recording is performed, and transferred onto the image receiving layer of the image receiving sheet by the irradiation of the laser beam. A multicolor image forming material characterized in that the difference in reflectance in the visible light region from the reflectance of the image forming layer is 10% or less for each image forming layer of each thermal transfer sheet. 2. An image receiving sheet having at least an image receiving layer on a support, and four or more types of thermal transfer sheets containing yellow, magenta, cyan, and black having at least a photothermal conversion layer and an image forming layer on the support. By using, the image forming layer of each thermal transfer sheet and the image receiving layer of the image receiving sheet are overlapped facing each other, laser light is irradiated, and the laser light irradiation region of the image forming layer is transferred onto the image receiving layer of the image receiving sheet. A multicolor image forming material for image recording, which shows the hue of the image forming layer immediately after image recording of the image forming layer transferred onto the image receiving layer of the image receiving sheet by irradiation of laser light and the hue after the exposure. A multicolor image-forming material having a color difference of 2 or less for each image forming layer of each thermal transfer sheet. 3. The multicolor image forming material according to claim 1, wherein in each of the thermal transfer sheets, the binder resin of the photothermal conversion layer has an SP value of 25 or more which is derived by the Okitsu method. 4. The light-heat converting substance of the light-heat converting layer is a cyanine dye and has a structure represented by the following general formula (A). Color image forming material. General formula (A): (In the general formula (A), Z represents an atomic group for forming a benzene ring, a naphthalene ring or a heteroaromatic ring, and T represents -O.
-, - S -, - Se -, - N (R 1) -, - C (R 2)
(R ³⁾ -, or ^{-C (R 4) = C (} R 5) - represents a.
R ¹ , R ² and R ³ each independently represent a hydrogen atom, an alkyl group, an alkenyl group or an aryl group, and R ⁴ and R 3
Each of ⁵ independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a carboxyl group, an acyl group, an acylamino group, a carbamoyl group, a sulfamoyl group, or a sulfonamide group. L represents a trivalent linking group formed by linking 5 or 7 methine groups by a conjugated double bond, M represents a divalent linking group, and X ⁺ represents a cation. )