JP2002274054A - Thermal transfer recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the humidity dependence of a thermal transfer recording material and to prevent the transfer of a photothermal conversion substance, especially, an infrared absorbing coloring matter to an image forming layer at the time of coating of an image forming layer. SOLUTION: In the thermal transfer recording material wherein at least a photothermal conversion layer containing photothermal conversion substance and a resin and the image forming layer containing a pigment and a resin are provided on a support in this order, a water insoluble resin is used as the resins added to the photothermal conversion layer and the image forming layer, and an image with a high resolving power of 2,400 dpi is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording material used in a multicolor image forming method for forming a high-resolution full-color image using a laser beam. In particular, the present invention relates to thermal transfer recording used in a color proof (DDCP: direct digital color proof) in printing field or a multicolor image forming method useful for producing a mask image by laser recording from a digital image signal. About the material.

[0002]

2. Description of the Related Art In the field of graphic arts, a printing plate is printed using a set of color separation films prepared from a color original by using a lithographic film. In order to check for errors in the color separation process and the necessity of color correction, a color proof is made from the color separation film. A color proof is required to have high resolution which enables high reproducibility of a halftone image, and high performance such as high process stability. In addition, in order to obtain a color proof similar to an actual printed matter, as a material used for the color proof, a material used for an actual printed matter, for example, a printing paper as a base material and a pigment as a coloring material are used. Is preferred. Also,
As a method for producing a color proof, there is a strong demand for a dry method using no developer.

As a dry-type color proofing method, with the recent widespread use of digitization systems in the pre-printing process (prepress field), a recording system for directly producing a color proof from digital signals has been developed. The purpose of such an electronic system is to produce a color proof having a high image quality, and generally reproduces a halftone image of 150 lines / inch or more. In order to record a proof of high image quality 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. For this reason, it is necessary to develop a recording material that exhibits high recording sensitivity to laser light and high resolution that enables high-definition halftone dots to be reproduced.

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 pigment which is heat-meltable, a binder, etc. are provided on a support. Heat-melt transfer sheet having an image forming layer dispersed in the components
No. 58045) is known. In the image forming method using these recording materials, the heat generated in the laser light irradiation area of the light-to-heat conversion layer melts the image forming layer corresponding to the area, and is transferred onto the image receiving sheet laminated on the transfer sheet. Then, a transfer image is formed on the image receiving sheet.

Japanese Patent Application Laid-Open No. 6-219052 discloses that a light-to-heat conversion layer containing a light-to-heat conversion substance, a very thin (0.03-0.3 μm) heat-peeling layer, and a coloring material are provided on a support. There is disclosed a thermal transfer sheet provided with an image forming layer in this order. In this thermal transfer sheet, the laser beam is irradiated, whereby the bonding force between the image forming layer and the light-to-heat conversion layer that are bonded by the interposition of the thermal release layer is reduced, 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", and specifically, in a region irradiated with laser light, the heat release layer partially decomposes and evaporates. This utilizes a phenomenon in which the bonding force between the image forming layer and the light-to-heat conversion layer is weakened, and the image forming layer in that region is transferred to the image receiving sheet laminated thereon.

According to these image forming methods, a printing paper having an image receiving layer (adhesive layer) attached thereto can be used as an image receiving sheet material, and multicolor images can be formed by transferring images of different colors onto the image receiving sheet one after another. The image forming method has an advantage that it can be easily obtained. In particular, an image forming method utilizing ablation has an advantage that a high-definition image can be easily obtained, and is color proof (DDCP: direct digital color proof) Alternatively, it is useful for producing a high-definition mask image.

When recording an image with a laser beam, a plurality of laser beams are used to shorten the recording time.
In recent years, multi-beam laser light has been used. When recording is performed using a laser beam that is a multi-beam using a conventional thermal transfer sheet, the image density of a transferred image formed on the image receiving sheet may be insufficient. In particular, the decrease in image density becomes significant when laser recording is performed with high energy. As a result of the study by the present inventors, it has been found that the decrease in image density is caused by transfer unevenness that occurs when laser irradiation is performed at high energy.

Hitherto, in a thermal transfer recording material, the use of a resin or a dye soluble in water or a hydrophilic solvent in a light-to-heat conversion layer has made humidity dependency worse. It was also found that the water-soluble image forming layer also had a large fluctuation in the moisture absorption rate, which was the cause of the deterioration of the humidity dependency. However, when the light-to-heat conversion substance is an infrared absorbing dye, there is a problem that when the image forming layer is coated with a solvent that dissolves the dye, the dye migrates to the coloring material layer when the image forming layer is coated.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to improve the humidity dependency of a thermal transfer recording material and to prevent a light-to-heat conversion material, especially an infrared absorbing dye, from migrating to an image forming layer during application of the image forming layer. That is.

[0010]

[Means for Solving the Problems] CTP (Computer To Pl
ate) In the era, it becomes filmless and requires proofs and contract proofs to replace analog color proofs. In order to obtain customer approval, color reproducibility consistent with printed matter and analog color proof is required, using the same pigment-based color material as printing ink, transferability to the actual paper is possible, and there is no moiré etc. DDCP system was developed. The goal is a large-size (A2 / B2) digital direct color proof system that can transfer to real paper, uses the same pigment-based color material as the printing ink, and has high print similarity. The present invention is a thermal transfer recording material which can be suitably used in a system capable of performing actual halftone dot recording and transferring to a real paper by using a laser thin film thermal transfer system, using a pigment coloring material.

The means for solving the above-mentioned problems are as follows. <1> In a thermal transfer recording material having a light-to-heat conversion layer containing at least a light-to-heat conversion substance and a resin on a support and an image forming layer containing a pigment and a resin in this order, the heat transfer recording material is contained in the light-to-heat conversion layer and the image formation layer. It is characterized by using a water-insoluble resin for both, 2400 dp
Thermal transfer recording material used to record high-resolution images of i or higher. <2> The resin contained in the light-to-heat conversion layer has an SP value of 16 to
Characterized by being dissolved in a hydrophobic solvent which is 22 <1>
2. The thermal transfer recording material according to item 1. <3> The resin contained in the image forming layer has an SP value of 16 to
30. The thermal transfer recording material as described in <1> or <2>, which is dissolved in a non-aqueous solvent of No. 30. <4> When providing the photothermal conversion layer, a hydrophobic solvent is used as a solvent for dissolving the resin, and when providing the image forming layer, a non-aqueous solvent is used as a solvent for dissolving the resin. <3> The thermal transfer recording material described in any one of the above. <5> The method according to any one of <1> to <4>, wherein the solubility of the light-to-heat conversion material in the light-to-heat conversion layer in a coating solvent for forming the image forming layer is 1 wt% or less. Thermal transfer recording material. <6> The thermal transfer according to any one of <1> to <5>, wherein the solubility of the resin of the photothermal conversion layer in a coating solvent for forming the image forming layer is 1 wt% or less. Recording material. <7> The resin according to any one of <1> to <6>, wherein the resin of the light-to-heat conversion layer has a solubility of 0.1 wt% or more in a coating solvent for forming the light-to-heat conversion layer. Thermal transfer recording material. <8> The thermal transfer recording according to any one of <1> to <7>, wherein the solubility of the light-to-heat conversion substance in a coating solvent for forming the light-to-heat conversion layer is 0.1 wt% or more. material. <9> The thermal transfer recording material according to any one of <1> to <8>, wherein the photothermal conversion material is an infrared absorbing dye. <10> The resin according to any one of <1> to <9>, wherein the resin of the image forming layer has a solubility of 0.1 wt% or more in a coating solvent for forming the image forming layer. Thermal transfer recording material. <11> The thermal transfer recording material according to any one of <1> to <10>, wherein an intermediate layer is provided between the light-heat conversion layer and the image forming layer. <12> The method for producing a thermal transfer recording material according to any one of <1> to <11>, wherein the thermal transfer recording material is formed by sequential coating. <13> Using an image receiving material having an image receiving layer and a thermal transfer recording material having at least a photothermal conversion layer and an image forming layer on a support, the image forming layer of the thermal transfer recording material and the image receiving layer of the image receiving sheet are opposed to each other. A multicolor image forming method comprising the steps of: irradiating light from the support side of the thermal transfer recording material, transferring the light-irradiated area of the image forming layer onto the image receiving layer of the image receiving sheet, and recording the image. > A multicolor image forming method using the thermal transfer recording material according to any one of <12>.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The thermal transfer recording material of the present invention will be described below, but is simply referred to as a thermal transfer sheet for convenience.
The thermal transfer sheet of the present invention realizes a thermal transfer image with sharp halftone dots, and transfers the book paper and B2 size recording (51
5mm × 728mm, B2 size is 543mm
.Times.765 mm). This thermal transfer image can be a halftone image corresponding to the number of printing lines at a resolution of 2400 to 2540 dpi. Since each halftone dot has almost no bleeding or chipping and a very sharp shape, a high range of halftone dots from highlight to shadow can be formed clearly. As a result, it is possible to output high-quality halftone dots at the same resolution as that of the image setter or the CTP setter, and to reproduce halftone dots and gradations with good print similarity.

The thermal transfer image has a sharp halftone dot shape, so that a halftone dot corresponding to a laser beam can be faithfully reproduced. In addition, since the dependency of recording characteristics on environmental temperature and humidity is very small, a wide range of temperature and humidity environments can be obtained. Under the above conditions, stable reproducibility of both hue and density can be obtained. This thermal transfer image is formed using the coloring pigment used in the printing ink, and has high repetition
A CMS (color management system) can be realized. In addition, this thermal transfer image can be made to substantially match the hue of Japan color, SWOP color and the like, 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 the same as that of the printed matter. Can be shown.

Further, since the thermal transfer image has a sharp dot shape, fine lines of fine characters can be reproduced clearly.
The heat generated by the laser beam is transmitted to the transfer interface without diffusing in the plane direction, and the image forming layer is sharply broken at the interface between the heated portion and the non-heated portion. For this purpose, the thinning of the light-to-heat conversion layer in the thermal transfer sheet and the mechanical properties of the image forming layer are controlled. By the way, in the simulation, it is estimated that the light-to-heat conversion layer instantaneously reaches approximately 700 ° C., and if the film is thin, deformation or destruction is likely to occur. When the deformation / destruction occurs, the light-to-heat conversion layer is transferred to the image receiving sheet together with the transfer layer, or the transferred image becomes non-uniform. On the other hand, in order to obtain a predetermined temperature, the photothermal conversion substance must be present in a high concentration in the film, which causes problems such as precipitation of a dye and migration to an adjacent layer. For this reason, it is preferable to reduce the thickness of the light-to-heat conversion layer to about 0.5 μm or less by selecting an infrared absorbing dye having excellent light-to-heat conversion characteristics and a heat-resistant binder such as a polyimide.

Generally, when the light-to-heat conversion layer is deformed or the image forming layer itself is deformed by high heat, the image forming layer transferred to the image receiving layer has a thickness unevenness corresponding to the sub-scanning pattern of the laser beam. And the resulting image becomes non-uniform and the apparent transfer density decreases. 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 the dots is impaired and the sensitivity is lowered. In order to balance these conflicting performances, it is preferable to improve transfer unevenness by adding a low melting point substance such as a wax to the image forming layer. Also, by adding inorganic fine particles instead of the binder, the layer thickness is appropriately increased, so that the image forming layer is sharply broken at the interface between the heated part and the unheated part, and the dot sharpness and sensitivity are maintained. In addition, transfer unevenness can be improved.

In general, low-melting substances such as wax are
It tends to seep or crystallize on the surface of the image forming layer,
In some cases, there is a problem in image quality or stability of the thermal transfer sheet over time. In order to cope with this problem, it is preferable to use a low melting point substance having a small difference in SP value from the polymer of the image forming layer. Can be prevented. It is also preferable to mix several kinds of low-melting substances having different structures so as to make them eutectic to prevent crystallization. As a result, an image having a sharp dot shape and less unevenness can be obtained.
In general, when the coating layer of the thermal transfer sheet absorbs moisture, the mechanical and thermal properties of the layer change, and the recording environment becomes dependent on humidity. In order to reduce the temperature / humidity dependency, it is preferable that the dye / binder system of the light-to-heat conversion layer and the binder system of the image forming layer are organic solvent systems. Further, it is preferable to select polyvinyl butyral as a binder for the image receiving layer and to introduce a polymer hydrophobizing technique in order to reduce the water absorption. Examples of the polymer hydrophobization technique include reacting a hydroxyl group with a hydrophobic group and crosslinking two or more hydroxyl groups with a hardener as described in JP-A-8-238858.

In general, the image forming layer also receives heat of about 500 ° C. or more during printing by laser exposure, and some pigments conventionally used are thermally decomposed. This can be prevented by adopting it in the image forming layer. And, by high heat at the time of printing,
To prevent the hue from changing when the infrared absorbing dye migrates from the light-to-heat conversion layer to the image forming layer, the light-to-heat conversion layer is designed with a combination of the infrared-absorbing dye / binder with strong holding power as described above. Is preferred.

In general, in high-speed printing, energy becomes insufficient, and a gap corresponding to the interval of laser sub-scanning occurs. As described above, increasing the concentration of the dye in the light-to-heat conversion layer and reducing the thickness of the light-to-heat conversion layer / image forming layer can increase the efficiency of heat generation / transmission. Further, it is preferable to add a low-melting substance to the image forming layer for the purpose of increasing the effect of slightly flowing the image forming layer upon heating and filling the gap and 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 sufficiently impart the strength of the transferred image, it is preferable to employ, 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 a 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 since an image is formed by controlling the adhesive force between the two sheets. If the clearance between the materials is widened due to foreign matter such as dust, image defects and image transfer unevenness occur. In order to prevent such image defects and image transfer unevenness, it is preferable to form uniform unevenness on the thermal transfer sheet to improve the air flow and obtain a uniform clearance.

As a method for forming irregularities on the thermal transfer sheet, there are generally post-treatments such as embossing, and addition of a matting agent to the coating layer. However, addition of a matting agent is preferable for simplifying the manufacturing process and stabilizing the material over time. . The matting agent needs to be larger than the thickness of the coating layer, and if the matting agent is added to the image forming layer, a problem occurs in that the image of the portion where the matting agent is present will be lost. It is preferable to add it to the conversion layer, whereby the image forming layer itself has a substantially uniform thickness, and a defect-free image can be obtained on the image receiving sheet.

In order to reliably reproduce the sharp dots as described above, a high-precision design is also required on the recording device side. The basic configuration is the same as that of the conventional laser thermal transfer recording apparatus. This configuration is a so-called heat mode outer drum recording system in which a recording head having a plurality of high-power lasers irradiates a laser onto a thermal transfer sheet and an image receiving sheet fixed on a drum to perform recording. Among them, the following embodiments are preferred configurations. The supply of the image receiving sheet and the thermal transfer sheet is a fully automatic roll supply. The image receiving sheet and the thermal transfer sheet are fixed to the recording drum by vacuum suction. A number of vacuum suction holes are formed on the recording drum, and the inside of the drum is depressurized by a blower, a decompression pump, or the like, so that the sheet is adsorbed on the drum.
The size of the thermal transfer sheet is made larger than that of the image receiving sheet because the thermal transfer sheet is further attracted from above the image receiving sheet. The air between the thermal transfer sheet and the image receiving sheet, which has the greatest effect on the recording performance, is sucked from the area of the thermal transfer sheet only outside the image receiving sheet.

In the present apparatus, it is assumed that a large number of sheets having a large area of B2 size can be stacked and stacked on a discharge table.
For this purpose, a method is employed in which air is blown out between the two sheets to float the sheet discharged later. FIG. 2 shows a configuration example of the present apparatus. A sequence in the present apparatus as described above will be described. 1) The sub-scanning axis of the recording head 2 of the recording apparatus 1 returns to the origin by the sub-scanning rail 3, and the main scanning rotation axis of the recording drum 4 and the thermal transfer sheet loading unit 5 return to the origin. 2) The image receiving sheet roll 6 is unwound by the transport roller 7, and the leading end of the image receiving sheet is vacuum-suctioned and fixed on the recording drum 4 via a suction hole provided in the recording drum. 3) The squeeze roller 8 descends onto the recording drum 4 and stops while the image receiving sheet is further conveyed by a specified amount by rotation of the drum while holding down the image receiving sheet, and is cut to a specified length by the cutter 9. 4) The recording drum 4 further makes one revolution, and the loading of the image receiving sheet is completed. 5) Next, in the same sequence as the image receiving sheet, the first color-black thermal transfer sheet K is fed out from the thermal transfer sheet roll 10K, cut, and loaded. 6) Next, the recording drum 4 starts rotating at a high speed, the recording head 2 on the sub-scanning rail 3 starts to move, and when the recording head reaches a recording start position, the recording head 2 irradiates the recording laser onto the recording drum 4 according to the recording image signal. Is done. The irradiation ends at the recording end position, and the sub-scanning rail operation and the drum rotation stop. Return the recording head on the sub-scanning rail to the origin. 7) With the image receiving sheet left on the recording drum, only the thermal transfer sheet K is peeled off. Therefore, the front end of the thermal transfer sheet K is hooked with a nail and pulled out in the discharge direction, and is discarded from the discard port 32 to the discard box 35. 8) Repeat steps 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 from the thermal transfer sheet roll 10C, the third color-magenta thermal transfer sheet M is from the thermal transfer sheet roll 10M, and the fourth color-yellow thermal transfer sheet Y is sequentially from the thermal transfer sheet roll 10Y. It is paid out. This is the opposite of the general printing order, because the color order on the paper is reversed by the paper transfer in a later step. 9) When the four colors are completed, the recorded image receiving sheet is finally discharged to the discharge table 31. The method of peeling off from the drum is the same as that of the thermal transfer sheet of 7), but unlike the thermal transfer sheet, it is not discarded. When the sheet is discharged to the discharge table, air 34 is blown out from below the discharge port 33 to enable stacking of a plurality of sheets.

A transport roller 7 at either a supply site or a transport site of the thermal transfer sheet roll and the image receiving sheet roll.
It is preferable to use an adhesive roller having an adhesive material disposed on the surface.

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

The adhesive material disposed on the surface of the adhesive roller includes ethylene-vinyl acetate copolymer, ethylene-
Ethyl acrylate copolymer, polyolefin resin, polybutadiene resin, styrene-butadiene copolymer (S
(BR), styrene-ethylene-butene-styrene copolymer (SEBS), acrylonitrile-butadiene copolymer (NBR), polyisoprene resin (IR), styrene-isoprene copolymer (SIS), acrylic ester copolymer , Polyester resin, polyurethane resin, acrylic resin, butyl rubber, polynorbornene and the like.

The adhesive roller can clean the surface by contacting the surface 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.

Surface roughness of the surface of the image forming layer of the thermal transfer sheet
The absolute value of the difference between Rz and the surface roughness Rz of the back layer surface 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 the back layer surface is 3.0. The following is preferred. With such a configuration, image defects can be prevented in combination with the above-described cleaning means, transport jams can be eliminated, and dot gain stability can be improved.

In this specification, the surface roughness Rz is defined by JIS
Means the ten-point average surface roughness corresponding to the Rz (maximum height) of the mountain, from the highest surface to the fifth mountain height, using the average surface of the part extracted from the surface of the roughness by the reference area as the reference surface The distance between the average value of the valley floor and the average value of the depths of the valley bottoms from the deepest to the fifth is input and converted. For measurement, Tokyo Seimitsu Co., Ltd.
Use a 3D roughness meter (Surfcom 570A-3DF) made by Nissan.
The measurement direction is the vertical direction, the cutoff value is 0.08 mm, the measurement area is 0.6 mm × 0.4 mm, the feed pitch is 0.005 mm, and the measurement speed is 0.12 mm / s.

The absolute value of the difference between the surface roughness Rz of the surface of the image forming layer of the thermal transfer sheet and the surface roughness Rz of the surface of the back layer is as follows.
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 backside layer surface is 1.0.
The following is preferred from the viewpoint of further improving the above effects.

In another embodiment, the surface roughness of the surface of the image forming layer of the thermal transfer sheet and the surface of the back layer thereof and / or the surface roughness Rz of the front and back surfaces of the image receiving sheet is preferably 2 to 30 μm. With such a configuration, it is possible to prevent image defects in combination with the above-described cleaning means, eliminate conveyance jams, and further improve dot gain stability.

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

The glossiness greatly 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 glossiness is more suitable as an image forming layer for application to high-definition images, but high smoothness results in higher resistance during transport, and both are in a trade-off relationship.
When the glossiness is in the range of 80 to 99, both can be compatible and a balance can be obtained.

The Vickers hardness Hv of the adhesive material used for the adhesive roller should be 50 kg / mm ² (≒ 490 MPa) or less, and it should be possible to sufficiently remove foreign matter and to suppress image defects. Is preferred.

The Vickers hardness means that the facing angle is 13
This is a hardness measured by applying a static load to a 6-degree square pyramidal diamond indenter, and the Vickers hardness Hv is obtained by the following equation.

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

Further, in the present invention, the above-described foreign material is that the adhesive material used for the adhesive roller has an elastic modulus at 20 ° C. of 200 kg / cm ² (cm19.6 MPa) or less. It is preferable because dust can be sufficiently removed and image defects can be suppressed.

Next, an outline of a mechanism of forming a multicolor image by thin-film thermal transfer using a laser will be described with reference to FIG. An image forming laminate 30 in which the image receiving 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 is prepared. . The thermal transfer sheet 10 includes the support 1
2, on it, the light-to-heat conversion layer 14, and further thereon
The image receiving layer 20 includes an image forming layer 16 and a support 22.
And an image receiving layer 24 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 surface (FIG. 1A). When a laser beam is radiated imagewise in time from the support 12 side of the thermal transfer sheet 10 of the laminate 30, the laser light irradiated area of the photothermal conversion layer 14 of the thermal transfer sheet 10 generates heat, and the image forming layer 16 is heated.
The adhesive strength with the adhesive decreases (FIG. 1B). After that, when the image receiving sheet 20 and the thermal transfer sheet 10 are peeled off, the laser light irradiated area 16 ′ of the image forming layer 16 becomes
0 is transferred onto the image receiving layer 24 (FIG. 1C).

In forming a multicolor image, the laser beam used for light irradiation is preferably a multi-beam beam, and more preferably a multi-beam two-dimensional array. The multi-beam two-dimensional arrangement means that when recording by laser irradiation, a plurality of laser beams are used, and the spot arrangement of these laser beams is plural in a row in the main scanning direction and plural in a sub-scanning direction. This means that a two-dimensional plane array consisting of rows is used. By using a laser beam having a multi-beam two-dimensional array, the time required for laser recording can be reduced.

The laser beam to be used can be used without particular limitation as long as it is a multi-beam, and 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 beam 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 to half the wavelength through a second harmonic element can be used. In the multicolor image forming method, it is preferable to use a semiconductor laser beam in consideration of output power, ease 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).
μm), and the scanning speed is 1 m / sec or more (especially 3 m / sec or more).
It is preferable that

In the multicolor image formation, the thickness of the image forming layer in the black thermal transfer sheet is larger than the 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, it is possible to suppress a decrease in density due to uneven transfer when the black thermal transfer sheet is irradiated with laser. When the thickness of the image forming layer in the black thermal transfer sheet is less than 0.5 μm, when recording with high energy, the image density is greatly reduced due to transfer unevenness, and the image density required as a proof of printing is achieved. It can be difficult. This tendency becomes more remarkable under high-humidity conditions, and the concentration change due to the environment may be large. On the other hand, if the layer thickness exceeds 0.7 μm, the transfer sensitivity may decrease during laser recording, and the attachment of small dots may worsen, or the thin line may become thin. This tendency is more pronounced under low humidity conditions. Further, the resolution may be deteriorated. 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 thickness of the image forming layer in the black thermal transfer sheet is 0.5 to 0.7 μm, and the thickness of the image forming layer in the yellow, magenta and cyan thermal transfer sheets is 0 to 0.7 μm. .2 μm or more and 0.5 μm
It is preferably less than. The yellow, magenta,
When the layer thickness of the image forming layer in each of the thermal transfer sheets of cyan and cyan is less than 0.2 μm, the density may be reduced due to transfer unevenness during laser recording, while 0.5 μm
Above, the transfer sensitivity may decrease or the resolution may deteriorate. 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 types of carbon blacks having different coloring powers. This is preferable because the reflection density can be adjusted while keeping the ratio in a certain range. The coloring power of carbon black can be represented by various methods. For example, PVC black described in JP-A-10-140033 is used.
Blackness and the like. PVC blackness refers to the addition of carbon black to a PVC resin, dispersion and sheeting with two rolls, and carbon black “# 40” manufactured by Mitsubishi Chemical Corporation.
The blackness of “# 45” is set to 1 point and 10 points, respectively, and a reference value is determined.
The blackness of the sample was evaluated by visual sensation determination. PV
Two or more types of carbon blacks having different C blackness can be appropriately selected and used according to the purpose.

Hereinafter, a specific sample preparation method will be described. <Sample preparation method> Using a 250 cc Banbury mixer, 40% by mass of a sample carbon black is blended with LDPE (low density polyethylene) resin, and kneaded 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, the mixture is diluted with a two-roll mill at 120 ° C. so that the carbon black concentration becomes 1% by mass.

Diluting compound preparation conditions LDPE resin 58.3 g Calcium stearate 0.2 g Carbon black 40% by mass blended resin 1.5 g Slit width: 0.3 mm 65 ± 3μm
Into a film.

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

The thermal transfer recording using laser beam irradiation can convert a laser beam into heat, transfer the image forming layer containing a pigment to an image receiving sheet using the thermal energy, and form an image on the image receiving sheet. If present, 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 gaseous state, and is preferably a solid state or a softened state. Thermal transfer recording using laser light irradiation includes, for example, conventionally known melt-type transfer, ablation-based transfer, and sublimation-type transfer. Above all, the above-mentioned thin film transfer type,
The ablation type is preferable in that an image having a hue similar to printing is created. In addition, a thermal laminator is usually used to perform a process of transferring an image receiving sheet on which an image has been printed by a recording device to a printing paper (called “book paper”). When the image receiving sheet and the paper are overlapped and heat and pressure are applied, they adhere to each other, and then the image receiving sheet is peeled off from the paper,
Only the image receiving layer containing the image remains on the paper.

By connecting the above devices to a plate making system, a system capable of exhibiting a function as a color proof is constructed. As a system, it is necessary that a printed matter having an image quality as close as possible to a printed matter output from certain platemaking data be output from the recording device. Therefore, software for bringing colors and halftone dots closer to printed matter is required. Specific connection examples are described below. Plate making system (for example, Fuji Photo Film Cele
When proofing the printed material from bra), the system connection is as follows. CTP (Com
puter To Plate) Connect the system. By applying the printing plate thus output to a printing machine, a final printed matter is obtained. The recording device is connected to the plate making system as a color proof, and a PD system (registered trademark) is connected as proof drive software for bringing colors and halftone dots closer to the printed matter. Contone (continuous tone) data converted to raster data by the plate making system is converted to binary data for halftone dots, 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 according to a four-dimensional (black, cyan, magenta, yellow) table so that the color matches the printed matter.
Finally, the data is converted into binary data for a halftone dot so as to match the halftone dot of the printed matter, and output to a recording device. The four-dimensional table is created experimentally in advance and stored in the system. The experiment for making is as follows. An image in which important color data is printed via a CTP system and an image output from a recording device via a PD system are prepared, and their colorimetric values are compared to create a table so that the difference is minimized.

Hereinafter, the thermal transfer sheet and the image receiving sheet of the present invention suitably used in the recording apparatus of the above system will be described. [Thermal Transfer Sheet] The thermal transfer sheet of the present invention has at least a light-to-heat conversion layer and an image forming layer on a support, and further has other layers as necessary.

(Support) 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 preferably has rigidity, good dimensional stability, and withstands heat during image formation. Preferred examples of the support material include polyethylene terephthalate, polyethylene-2,6-naphthalate, polycarbonate, polymethyl methacrylate, polyethylene,
Polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene-acrylonitrile copolymer, polyamide (aromatic or aliphatic), polyimide,
Synthetic resin materials such as polyamide imide and polysulfone can be mentioned. Among them, biaxially stretched polyethylene terephthalate is preferable in consideration of mechanical strength and dimensional stability against heat. When a color proof is produced using laser recording, the support of the thermal transfer sheet is preferably formed of a transparent synthetic resin material that transmits laser light. The thickness of the support is 25 to 130 μm
Is preferably, and particularly preferably 50 to 120 μm. The center line average surface roughness Ra (measured based on JIS B0601 using a surface roughness measuring device (Surfcom, manufactured by Tokyo Seiki Co., Ltd.)) of the support on the image forming layer side may be less than 0.1 μm. preferable. The Young's modulus of the support in the longitudinal direction 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 GPa).
a) is preferred. 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 support width direction is preferably 3
３０30 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 this is not particularly necessary when it is necessary to increase the strength in the width direction. Further, the heat shrinkage at 100 ° C. for 30 minutes in the longitudinal direction and the width direction of the support is preferably 3% or less, more preferably 1.5% or less, and the heat shrinkage at 80 ° C. for 30 minutes is preferably 1%. Less than,
More preferably, it is 0.5% or less. The breaking strength is 5 to 100 kg / mm ² (ｍｍ49 to 980MP in both directions).
a), the elastic modulus is 100 to 2000 kg / mm ² (≒ 0.
98 to 19.6 GPa).

The support of the thermal transfer sheet may be subjected to a surface activation treatment and / or the provision of one or more undercoat layers in order to improve the adhesion to the light-to-heat conversion layer provided thereon. Is also good. Examples of the surface activation treatment include a glow discharge treatment and a corona discharge treatment. The material of the undercoat layer preferably has high adhesiveness to both surfaces of the support and the light-to-heat conversion layer, low thermal conductivity, and excellent heat resistance. Examples of such a material for the undercoat layer include styrene, styrene-butadiene copolymer, and gelatin. The thickness of the entire undercoat layer is usually 0.01 to 2 μm. If necessary, various functional layers such as an antireflection layer and an antistatic layer, or a surface treatment can be applied to the surface of the thermal transfer sheet opposite to the side on which the photothermal conversion layer is provided.

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

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

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

Further, conductive fine particles are used as an antistatic agent.
Can also be. As such conductive fine particles,
For example, ZnO, TiO_Two, SnO_Two, Al_TwoO_Three, In_Two
O_Three, MgO, BaO, CoO, CuO, Cu_TwoO, Ca
O, SrO, BaO_Two, PbO, PbO_Two, MnO_Three, M
oO_Three, SiO_Two, ZrO_Two, Ag_TwoO, Y_TwoO_Three, Bi
_TwoO_Three, Ti_TwoO_Three, Sb_TwoO_Three, Sb_TwoO_Five, K_TwoTi₆O₁₃,
NaCaP_TwoO₁₈, MgB_TwoO _FiveOxides such as CuS, Z
Sulfides such as nS; SiC, TiC, ZrC, VC, Nb
Carbides such as C, MoC and WC; Si_ThreeN_Four, TiN, Zr
N, VN, NbN, Cr_TwoNitride such as N; TiB_Two, Zr
B_Two, NbB_Two, TaB_Two, CrB, MoB, WB, La
B_FiveBorides such as TiSi_Two, ZrSi_Two, NbSi_Two, T
aSi_Two, CrSi_Two, MoSi_Two, WSi_TwoSilicides such as;
BaCO_Three, CaCO_Three, SrCO_Three, BaSO_Four, CaS
O_FourMetal salts such as SiN_Four-SiC, 9Al_TwoO_Three-2B_Two
O_ThreeAnd the like. One of these compounds may be used alone or in combination with two or more.
More than one species may be used in combination. Of these, SnO_Two, Z
nO, Al_TwoO_Three, TiO_Two, In_TwoO_Three, MgO, BaO
And MoO_ThreeAre preferred, and SnO_Two, ZnO, In_TwoO_ThreePassing
And TiO_TwoIs more preferable, and SnO_TwoIs particularly preferred.

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

When a conductive metal oxide is used as an antistatic agent, its particle size is preferably as small as possible to minimize light scattering. It is to 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 in the range of 0.003 to 0.2 μm. Here, the average particle diameter is a value including not only the primary particle diameter of the conductive metal oxide but also the particle diameter of a 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 from 10 to 1,000 parts by mass, and more preferably from 200 to 80 parts by mass, per 100 parts by mass of the binder.
0 parts by mass is more preferred. The amount of the antistatic agent contained in the second back layer is preferably from 0 to 300 parts by mass, more preferably from 0 to 100 parts by mass, based on 100 parts by mass of the binder.

Examples of the binder used for forming the first and second back layers include homopolymers and copolymers of acrylic acid monomers such as acrylic acid, methacrylic acid, acrylates and methacrylates. , Nitrocellulose, methylcellulose, ethylcellulose,
Cellulosic polymers such as cellulose acetate,
Polyethylene, polypropylene, polystyrene, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, polyvinylpyrrolidone, polyvinyl butyral, copolymer of vinyl polymer and vinyl compound such as polyvinyl alcohol, polyester, polyurethane, polyamide Such condensation polymers, rubber-based thermoplastic polymers such as butadiene-styrene copolymers, polymers obtained by polymerizing and crosslinking photopolymerizable or thermopolymerizable compounds such as epoxy compounds, melamine compounds, and the like. .

(Light-to-heat conversion layer) The light-to-heat conversion layer contains a light-to-heat conversion substance, a binder, and if necessary, a matting agent.
Further, if necessary, other components are contained.

The light-to-heat conversion substance is a substance having a function of converting the irradiated light energy into heat energy. Generally, it is a dye capable of absorbing laser light (including a pigment; the same applies hereinafter). When performing image recording with an infrared laser, it is preferable to use an infrared absorbing dye as the photothermal conversion substance. As the photothermal conversion substance, a substance having a solubility in a coating solvent for forming an image forming layer of 1 wt% or less is preferable. The solubility in a coating solvent for forming the light-heat conversion layer is 0.1.
It is preferably at least 1 wt%. When the solubility of the light-to-heat conversion material in each solvent is within the above range, the transfer of the light-to-heat conversion material to the image forming layer during application of the image forming layer can be prevented.

Examples of the dye include black pigments such as carbon black, macrocyclic compounds such as phthalocyanine and naphthalocyanine which have absorption in the visible to near infrared region,
Organic dyes (cyanine dyes such as indolenine dyes, anthraquinone dyes, azulene dyes, phthalocyanine dyes) and organic metal compound dyes such as dithiol nickel complexes used as laser absorbing materials for high-density laser recording such as optical discs Can be mentioned. Among them,
Cyanine dyes have a high extinction coefficient for light in the infrared region, so when used as a light-to-heat conversion material, the light-to-heat conversion layer can be made thinner, and as a result, the recording sensitivity of the heat transfer sheet is further improved. It is preferable because it can be performed. As the light-to-heat conversion material, an inorganic material such as a particulate metal material such as blackened silver can be used in addition to the pigment.

As a binder contained in the light-to-heat conversion layer, a water-insoluble resin is used, and a resin having at least strength enough to form a layer on a support and having high thermal conductivity is preferable. Above all, in order to improve the humidity dependence of the thermal transfer sheet, a resin that dissolves in a hydrophobic solvent having an SP value of 16 to 22 by 0.1 wt% or more is preferable, and a resin that dissolves by 1 wt% or more is particularly preferable. A general-purpose solvent having the above SP value is, specifically, cyclohexane (SP value: 16.
8), xylene (18.0), toluene (18.2), ethyl acetate (18.6), tetrahydrofuran (18.6), methyl ethyl ketone (19.0), acetone (20.3), cyclohexanone (20.3), 1,4-dioxane (20.5), 1, 3-dioxane (20.9) and the like. Further, the solubility in a coating solvent for forming the image forming layer is preferably 1% by weight or less, more preferably 0.1% by weight or less. The solubility in a coating solvent for forming the photothermal conversion layer is preferably 0.1 wt% or more,
More preferably, it is not less than wt%.

Further, when the resin is heat resistant and does not decompose even by the heat generated from the light-to-heat conversion material during image recording, the surface of the light-to-heat conversion layer after light irradiation can be used even if high-energy light irradiation is performed. Is preferable because the smoothness of the film can be maintained.
Specifically, a resin having a thermal decomposition temperature (temperature at which the mass is reduced by 5% in an air stream at a heating rate of 10 ° C./min by TGA (thermal mass spectrometry)) is preferably 400 ° C. or more, A resin having a decomposition temperature of 500 ° C. or higher is more preferable. Also, the binder preferably has a glass transition temperature of 200 to 400 ° C, more preferably 250 to 350 ° C. When the glass transition temperature is lower than 200 ° C., fogging may occur in an image to be formed, and when the glass transition temperature is higher than 400 ° C., the solubility of the resin may be reduced and the production efficiency may be reduced. In addition, it is preferable that the heat resistance (for example, thermal deformation temperature and thermal decomposition temperature) of the binder of the light-to-heat conversion layer is higher than the material used for the other layers provided on the light-to-heat conversion layer.

Specifically, acrylic resins such as polymethyl methacrylate, polycarbonate, polystyrene,
Vinyl chloride / vinyl acetate copolymer, vinyl resin such as polyvinyl alcohol, polyvinyl butyral, polyester, polyvinyl chloride, polyamide, polyetherimide, polysulfone, polyethersulfone, aramid,
Examples include polyurethane, epoxy resin, and urea / melamine resin.

The matting agent contained in the light-to-heat conversion layer includes inorganic fine particles and organic fine particles. Examples of 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 oxide, and the like. Examples include lead white, ziglite, quartz, diatomaceous earth, barlite, bentonite, mica, and synthetic mica. Examples of the organic fine particles include fluorine resin particles, guanamine resin particles, acrylic resin particles, styrene-acryl 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 .

A surfactant, a thickener, an antistatic agent, and the like may be further added to the light-to-heat conversion layer, if necessary.

The light-to-heat conversion layer is prepared by dissolving a light-to-heat conversion substance and a binder, adding a matting agent and other components as needed to prepare a coating solvent, coating the coating solution on a support, and drying the coating solution. It can be provided by doing. In order to dissolve the photothermal conversion substance and the binder, it is preferable to use the above-mentioned hydrophobic solvent. Coating and drying can be performed by using ordinary coating and drying methods. Drying is usually performed at a temperature of 300 ° C. or lower, preferably at a temperature of 200 ° C. or lower. When polyethylene terephthalate is used as the support, drying is preferably performed at a temperature of 80 to 150 ° C.

When the amount of the binder in the light-to-heat conversion layer is too small, the cohesive force of the light-to-heat conversion layer is reduced, and when the formed image is transferred to the image receiving sheet, the light-to-heat conversion layer is easily transferred together. It causes color mixing. On the other hand, if the amount of the polyimide resin is too large, the layer thickness of the light-to-heat conversion layer becomes large in order to achieve a certain light absorption rate, and the sensitivity tends to decrease. The mass ratio of the solid content of the light-to-heat conversion material to the binder in the light-to-heat conversion layer is preferably from 1:20 to 2: 1, and more preferably from 1:10 to 2: 1.
Further, it is preferable to make the light-to-heat conversion layer thin, as described above, since the sensitivity of the heat transfer sheet can be increased. The light-to-heat conversion layer preferably has a thickness of 0.03 to 1.0 μm,
More preferably, it is 5 to 0.5 μm.

It is preferable that the light-to-heat conversion layer has an optical density of 0.80 to 1.26 with respect to light having a wavelength of 808 nm, since the transfer sensitivity of the image forming layer is improved. In contrast, it is more preferable to have an optical density of 0.92 to 1.15. If the optical density at a wavelength of 808 nm 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 the ratio exceeds 1.26, the function of the light-to-heat conversion layer is affected at the time of recording, and fog may occur. In the present invention, the optical density of the light-to-heat conversion layer of the thermal transfer sheet refers to the absorbance of the light-to-heat conversion layer at the peak wavelength (808 nm) of the laser beam used when recording the image forming material of the present invention, and is a known spectrophotometer. Can be used for measurement. In the present invention, a UV-spectrophotometer UV-240 manufactured by Shimadzu Corporation was used. The optical density is a value obtained by subtracting the value of the support alone from the value including the support.

(Image Forming Layer) The image forming layer contains at least a pigment which is transferred to an image receiving sheet to form an image, and further contains a binder for forming a layer and, if desired, other components. I do. Pigments are generally classified into organic pigments and inorganic pigments.The former has properties such as excellent transparency of the coating film, and the latter generally has properties such as excellent concealing properties, and can be appropriately selected according to the application. I just need. When the thermal transfer sheet is used for printing color proofing, organic pigments that match or have a similar color tone to yellow, magenta, cyan, and black generally used for printing inks are preferably used. In addition, a metal powder, a fluorescent pigment, or the like may be used. Examples of preferably used 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 for each hue, but are not limited thereto.

1) Yellow Pigment Pigment Yellow
12 (CI No. 21090) Example) Permanent Yellow (Permanent Yellow) DHG (Clariant Japan K.K.)
Lionol Yellow 1212B (manufactured by Toyo Ink Mfg. Co., Ltd.), Irg
alite Yellow (Ilgarite Yellow)
LCT (Ciba Specialty Chemicals Co., Ltd.)
Pigment Yellow (manufactured by Dainippon Ink and Chemicals, Inc.)
13 (CI No. 21100) Example: Permanent Yellow (Permanent Yellow) GR (manufactured by Clariant Japan K.K.),
Lionol Yellow
1313 (manufactured by Toyo Ink Mfg. Co., Ltd.) Pigment Yellow
14 (CI No. 21095) Example) Permanent Yellow (Permanent Yellow) G (manufactured by Clariant Japan KK), L
ionol Yellow 14
01-G (manufactured by Toyo Ink Mfg. Co., Ltd.), Seika F
ast Yellow (Seika First Yellow)
2270 (manufactured by Dainichi Seika Kogyo Co., Ltd.), Symuler
Fast Yellow 4400 (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Yellow (Pigment Yellow)
17 (CI No. 21105) Example) Permanent Yellow (Permanent Yellow) GG02 (Clariant Japan K.K.)
Pigment Yellow (manufactured by Dainippon Ink and Chemicals, Inc.) 8GF (manufactured by Dainippon Ink and Chemicals, Inc.)
155 Example) Graphtol Yellow (Graftor Yellow) 3GP (manufactured by Clariant Japan KK) Pigment Yellow (Pigment Yellow)
180 (CI No. 21290) Example) Novoperm Yellow (Novo Palm Yellow) P-HG (manufactured by Clariant Japan K.K.),
PV Fast Yellow
HG (manufactured by Clariant Japan KK) Pigment Yellow (Pigment Yellow)
139 (CI No. 56298) Example) Novoperm Yellow (Novo Palm Yellow) M2R 70 (Clariant Japan K.K.)
Made)

2) Magenta Pigment Red (Pigment Red) 57:
1 (CI No. 15850: 1) Example) Graphtol Rubine L6B (manufactured by Clariant Japan KK), L
ionol Red (Rionol Red) 6B-42
90G (manufactured by Toyo Ink Mfg. Co., Ltd.), Irgalite
Rubine (Ilgarite 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) Hosterperm Pink (Hoster Palm Pink) E (manufactured by Clariant Japan K.K.), Li
onogen Magenta
5790 (manufactured by Toyo Ink Manufacturing Co., Ltd.), Fastog
en Super Magenta RH (Dainippon Ink & Chemicals, Inc.)
Pigment Red 53:
1 (CI No. 15585: 1) Example) Permanent Lake Red (Permanent Lake Red) LCY (manufactured by Clariant Japan KK), Symul
er Lake Red (Shimla Lake Red) C
conc (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red 48:
1 (CI No. 15865: 1) Example) Lionol Red 2B
3300 (manufactured by Toyo Ink Manufacturing Co., Ltd.), Symule
r Red (Shimler Red) NRY (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red (Pigment Red) 48:
2 (CI No. 15865: 2) Example) Permanent Red (Permanent Red) W2T (manufactured by Clariant Japan KK), Li
onol Red (Lionol Red) LX235
(Manufactured by Toyo Ink Manufacturing Co., Ltd.), Symler Red
(Shimler Red) 3012 (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red 48:
3 (CI No. 15865: 3) Example) Permanent Red (Permanent Red) 3RL (manufactured by Clariant Japan KK), Sy
muller Red (Shimler Red) 2BS (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Red (Pigment Red) 177
(CI. No. 65300) Example) Cromophthal Red (Chromophthal Red) A2B (manufactured by Ciba Specialty Chemicals Co., Ltd.)

3) Cyan pigment Pigment Blue (Pigment Blue) 15
(C.I. No. 74160) Example) Lionol Blue 7
027 (manufactured by Toyo Ink Manufacturing Co., Ltd.), Fastogen
Blue (fastogen blue) BB (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue (pigment blue) 1
5: 1 (CI No. 74160) Example) Hosterperm Blue (Hoster Palm Blue) A2R (manufactured by Clariant Japan KK),
Fastogen Blue (fastogen blue)
5050 (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue 1
5: 2 (CI No. 74160) Example) Hosterperm Blue (Hoster Palm Blue) AFL (manufactured by Clariant Japan KK),
Irgalite Blue (Irgalite Blue)
BSP (Ciba Specialty Chemicals Co., Ltd.)
Pigment Blue (Pigment Blue) 1
5: 3 (CI No. 74160) Example) Hosterperm Blue (Hoster Palm Blue) B2G (manufactured by Clariant Japan K.K.),
Lionol Blue FG7330 (manufactured by Toyo Ink Mfg. Co., Ltd.), Cromo
phtal Blue (Chromophtal Blue) 4GN
P (made by Ciba Specialty Chemicals Co., Ltd.),
Fastogen Blue (fastogen blue)
FGF (manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue 1
5: 4 (CI No. 74160) Example) Hosterperm Blue (Hoster Palm Blue) BFL (manufactured by Clariant Japan KK),
Cyanine Blue (Cyanine Blue) 700-
10FG (manufactured by Toyo Ink Mfg. Co., Ltd.), Irgalit
e Blue (Irgarite Blue) GLNF (manufactured by Ciba Specialty Chemicals Co., Ltd.), Fast
oogen Blue FGS
(Manufactured by Dainippon Ink and Chemicals, Inc.) Pigment Blue 1
5: 6 (CI No. 74160) Example) Lionol Blue E
S (manufactured by Toyo Ink Mfg. Co., Ltd.) Pigment Blue 60
(C.I. No. 69800) Example) Hosterperm Blue (Hoster Palm Blue) RL01 (Clariant Japan K.K.)
Manufactured by Toyo Ink Mfg. Co., Ltd.), Lionogen Blue (Rionogen Blue) 6501 (manufactured by Toyo Ink Mfg. Co., Ltd.)

4) Black Pigment Pigment Black (Pigment Black)
7 (carbon black CI No. 77266) Example) Mitsubishi carbon black MA100 (manufactured by Mitsubishi Chemical Corporation), Mitsubishi carbon black # 5 (manufactured by Mitsubishi Chemical Corporation), Black Pearls (Black Pearls) 430 (Cabot) Co. (Cabot Corporation)
Pigments that can be used in the present invention include “Pigment Handbook, edited by Japan Pigment Technical Association, Seibundo Shinkosha, 198
9 "," COLOUR INDEX, THE SOCIETY OF
DYES & COLOURIST, THIRD EDITION, 1987 "and the like, and the product can be selected as appropriate.

The pigment has an average particle size of from 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 hinder the adhesion between the image forming layer and the image receiving layer,
This may hinder the transparency of the image forming layer.

A water-insoluble resin is used as a binder for the image forming layer. A resin that dissolves in a nonaqueous solvent having an SP value of 16 to 30 at 0.1 wt% or more is preferable, and 1 wt%
A resin that dissolves as described above is more preferable. Examples of the general-purpose solvent having the SP value include cyclohexanol (SP value: 23.3), n-propyl alcohol (24.3), ethanol (26.0), and methanol (29.7) in addition to the hydrophobic solvent. Further, the solubility in a coating solvent for forming the image forming layer is preferably at least 0.1 wt%, more preferably at least 1 wt%.

Further, a resin which is an amorphous organic high molecular polymer having a softening point of 40 to 150 ° C. is preferable. As the amorphous organic high-molecular polymer, for example, butyral resin, polyamide resin, polyethyleneimine resin, sulfonamide resin, polyester polyol resin, petroleum resin, styrene, vinyltoluene, α-methylstyrene, 2-methylstyrene, Styrene and its derivatives such as chlorostyrene, vinylbenzoic acid, sodium vinylbenzenesulfonate and aminostyrene, and homo- and copolymers of substituted methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate and hydroxyethyl methacrylate And methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, α-
Acrylic acid esters such as ethylhexyl acrylate and acrylic acid, butadienes, dienes such as isoprene,
Use of vinyl monomers such as acrylonitrile, vinyl ethers, maleic acid and maleic esters, maleic anhydride, cinnamic acid, vinyl chloride, vinyl acetate, or copolymers with other monomers Can be. These resins can be used as a mixture of two or more kinds.

The image forming layer preferably contains 30 to 70% by mass of a pigment, more preferably 30 to 50% by mass. Further, the image forming layer is made of a resin of 70%.
The content is preferably from 30 to 30% by mass, more preferably from 70 to 40% by mass.

The image forming layer can contain the following components as the other components. Waxes Examples of the waxes include mineral waxes, natural waxes, and synthetic waxes. Examples of the mineral wax include petroleum wax such as paraffin wax, microcrystalline wax, ester wax, and oxidized wax, montan wax, ozokerite, and ceresin. Above all, paraffin wax is preferred. The paraffin wax is separated from petroleum, and various types are commercially available depending on the melting point. Examples of the natural waxes include vegetable waxes such as carnauba wax, wood wax, ouriculi wax, and spal wax, and animal waxes such as beeswax, insect wax, shellac wax, and whale wax.

The synthetic wax is generally used as a lubricant, and usually comprises a higher fatty acid compound. Examples of such synthetic waxes include the following. 1) Fatty acid-based wax 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, azelaic acid and the like.
In addition, metal salts such as the above fatty acids (for example, K, Ca, Z
n, Mg, etc.). 2) Fatty acid ester-based wax Specific examples of the fatty acid ester include ethyl stearate, lauryl stearate, ethyl behenate, hexyl behenate, and behenyl myristate. 3) Fatty acid amide-based wax Specific examples of the amide of the fatty acid include stearic acid amide and lauric acid amide. 4) Aliphatic alcohol wax A straight-chain saturated aliphatic alcohol represented by the following general formula: CH
₃ (CH ₂ ) _n OH In the above formula, n represents an integer of 6 to 28. Specific examples include stearyl alcohol and the like.

Among the synthetic waxes 1) to 4), higher fatty acid amides such as stearic acid amide and lauric acid amide are particularly preferable. In addition, the said wax-type compound can be used individually or in suitable combination as needed.

Plasticizer The plasticizer is preferably an ester compound. Dibutyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, dilauryl phthalate, butyllauryl phthalate, Phthalates such as butylbenzyl phthalate, di (2-diphenyl adipate)
Aliphatic dibasic acid esters such as ethylhexyl) and di (2-ethylhexyl) sebacate; phosphoric acid triesters such as tricresyl phosphate and tri (2-ethylhexyl) phosphate; polyol polyesters such as polyethylene glycol ester; epoxy Known plasticizers such as an epoxy compound such as a fatty acid ester can be used. Of these, esters of vinyl monomers, particularly esters of acrylic acid or methacrylic acid, are preferred because they have a large effect of improving transfer sensitivity, improving transfer unevenness, and controlling elongation at break by addition.

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 and the like.

The plasticizer may be a polymer, and among them, polyester is preferable because of its large addition effect and difficulty in diffusing under storage conditions. Examples of the polyester include sebacic acid-based polyester and adipic acid-based polyester. The additives to be contained in the image forming layer are not limited to these. The plasticizer may be used alone or in combination of two or more.

If the content of the additive in the image forming layer is too large, the resolution of the transferred image is reduced, the film strength of the image forming layer itself is reduced, and the adhesion between the light-to-heat conversion layer and the image forming layer is reduced. In some cases, the transfer of the unexposed portion to the image receiving sheet occurs due to a decrease in the force. From the above viewpoint, the content of the wax is preferably from 0.1 to 30% by mass, more preferably from 1 to 20% by mass of the total solids in the image forming layer. The content of the plasticizer is preferably from 0.1 to 20% by mass, more preferably from 0.1 to 10% by mass of the total solids in the image forming layer.

Others The image forming layer further contains a surfactant,
It may contain inorganic or organic fine particles (metal powder, silica gel, etc.), oils (linseed oil, mineral oil, etc.), thickeners, antistatic agents and the like. Except for obtaining a black image, the energy required for transfer can be reduced by including a substance that absorbs the wavelength of the light source used for image recording. The substance that absorbs the wavelength of the light source may be any of a pigment and a dye. It is preferable in terms of color reproduction to use a dye having a large absorption at the wavelength of the light source. Examples of near infrared dyes include:
The compounds described in JP-A-3-103476 can be exemplified.

For the image forming layer, a coating solution prepared by dissolving or dispersing the pigment and the binder and the like is prepared, and this is coated on the light-to-heat conversion layer (on the following intermediate layer, if provided). , By drying. As the solvent used for preparing the coating solution, the above-mentioned non-aqueous solvent is preferable. Coating and drying can be performed by using ordinary coating and drying methods.

An intermediate layer can be provided between the light-to-heat conversion layer and the image forming layer of the thermal transfer sheet of the present invention. As the intermediate layer, a heat-sensitive material including a heat-sensitive material that generates gas by the action of heat generated in the light-to-heat conversion layer or releases attached water and the like, thereby weakening the bonding strength between the light-to-heat conversion layer and the image forming layer. A release layer can be mentioned. Examples of such heat-sensitive materials include compounds (polymers or low-molecular compounds) that decompose or degrade due to heat to generate gas, and compounds that absorb or adsorb a considerable amount of easily vaporizable gas such as water (polymer). Or low molecular weight compounds). These may be used in combination.

Examples of the polymer which decomposes or degrades by heat to generate a gas include self-oxidizing polymers such as nitrocellulose, chlorinated polyolefins, chlorinated rubber, polyvinyl chloride, polyvinyl chloride, and polyvinylidene chloride. Such halogen-containing polymers, acrylic polymers such as polyisobutyl methacrylate in which volatile compounds such as moisture are adsorbed, cellulose esters such as ethyl cellulose in which volatile compounds such as water are adsorbed, and volatile compounds such as water. Natural polymer compounds such as adsorbed gelatin can be exemplified. Examples of the low molecular weight compound which decomposes or degrades by heat to generate a gas include a compound which generates a gas upon exothermic decomposition such as a diazo compound or azide compound. In addition, the decomposition or deterioration of the heat-sensitive material due to heat as described above preferably occurs at 280 ° C. or less, particularly preferably at 230 ° C. or less.

When a low-molecular 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, a polymer which itself decomposes or degrades by heat to generate a gas can be used, but a normal binder having no such properties can also be used. When a heat-sensitive low-molecular compound and a binder are used in combination, the mass ratio of the former to the latter is preferably 0.02: 1 to 3: 1,
More preferably, the ratio is 0.05: 1 to 2: 1. The heat-sensitive release layer desirably covers the light-to-heat conversion layer over substantially the entire surface thereof.
1 μm, and preferably in the range of 0.05 to 0.5 μm.

On a support, a light-to-heat conversion layer, a heat-sensitive release layer,
In the case of a thermal transfer sheet having a configuration in which the image forming layers are laminated in this order, the heat-sensitive release layer decomposes and degrades by the heat transmitted from the light-to-heat conversion layer to generate gas. Then, due to the decomposition or the generation of gas, the heat-sensitive peeling layer partially disappears, or cohesive failure occurs in the heat-sensitive peeling layer, and the bonding force between the light-heat conversion layer and the image forming layer decreases. For this reason, depending on the behavior of the heat-sensitive release layer, a part of the heat-sensitive release layer may adhere to the image forming layer and appear on the surface of a finally formed image, which may cause color mixing of the image. Therefore, even when such transfer of the heat-sensitive release layer occurs, the heat-sensitive release layer is hardly colored, that is, high in visible light, so that no visual color mixture appears in the formed image. It is desirable to show permeability. Specifically, the light-absorbing rate of the heat-sensitive release layer is 50% or less, preferably 1 to visible light.
0% or less. In addition, instead of providing an independent heat-sensitive release layer on the thermal transfer sheet, the heat-sensitive material is added to a light-to-heat conversion layer coating solution to form a light-to-heat conversion layer. It can also be set as a structure.

The thermal transfer sheet of the present invention comprises a support or an undercoat layer provided on the support, a light-to-heat conversion layer,
The image forming layer is provided in this order (in the case of providing an intermediate layer, a light-to-heat conversion layer, an intermediate layer, and an image forming layer are arranged in this order). After the application and drying of the lower layer are completed, the upper layer is sequentially applied. It is preferably carried out in a method as described above.

It is preferable that the static friction coefficient of the outermost layer on the side of the thermal transfer sheet on which the image forming layer is provided be 0.35 or less, 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 roll contamination when the thermal transfer sheet is conveyed, and to improve the quality of the formed image. The method for measuring the coefficient of static friction is described in Japanese Patent Application No. 2000-85759.
According to the method described in paragraph [0011]. The smoother value of the surface of the image forming layer is 0.5 to 50 mmHg at 23 ° C and 55% RH (≒
0.0665 to 6.65 kPa) and Ra is 0.05
To 0.4 [mu] m, whereby the number of microscopic voids where the image receiving layer and the image forming layer cannot contact each other on the contact surface can be reduced, which is preferable in terms of transfer and further image quality. The Ra value is measured by a surface roughness measuring device (Surfcom,
It can be measured based on JIS B0601 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 the thermal transfer sheet is charged according to US Federal Government Test Standard 4046, the charge 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 composed of a support,
One or more image receiving layers are provided, and if desired, one or more of a cushion layer, a release layer, and an intermediate layer are provided between the support and the image receiving layer. 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 a support, a plastic sheet, a metal sheet, a glass sheet, a resin-coated paper,
Examples include ordinary sheet-like substrates such as paper and various composites. Examples of the plastic sheet include a polyethylene terephthalate sheet, a polycarbonate sheet, a polyethylene sheet, a polyvinyl chloride sheet, a polyvinylidene chloride sheet, a polystyrene sheet, a styrene-acrylonitrile sheet, and a polyester sheet. As the paper, 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 is, for example, a thermoplastic resin, a mixed melt obtained by mixing an inorganic pigment or a filler made of an incompatible polymer or the like with the thermoplastic resin, a single layer or a multilayer by a melt extruder. It can be produced by forming a film and further stretching it uniaxially 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, a polyolefin resin such as polypropylene and a polyethylene terephthalate resin are preferable because of good crystallinity, good stretchability, and easy void formation. It is preferable to use the above-mentioned polyolefin resin or polyethylene terephthalate resin as a main component, and appropriately use a small amount of another thermoplastic resin in combination. As the inorganic pigment used as the filler, those having an average particle size of 1 to 20 μm are preferable, and calcium carbonate, clay, diatomaceous earth, titanium oxide, aluminum hydroxide, silica and the like can be used. When polypropylene is used as the thermoplastic resin as the incompatible resin used as the filler, it is preferable to combine polyethylene terephthalate as the filler. Details of the support having minute voids (voids) are described in Japanese Patent Application No. 11-290570. The content of the filler such as an inorganic pigment in the support is 2 to 30 by volume.
% Is common.

The thickness of the support of the image receiving sheet is usually from 10 to
It is 400 μm, preferably 25 to 200 μm. Further, the surface of the support is subjected to a surface treatment such as a corona discharge treatment or a glow discharge treatment in order to enhance the adhesion with the image receiving layer (or the cushion layer) or the adhesion with the image forming layer of the thermal transfer sheet. It may be.

(Image-Receiving Layer) In order to transfer and fix the image-forming layer on the surface of the image-receiving sheet, it is preferable to provide one or more image-receiving layers on a support. The image receiving layer is preferably a layer formed mainly of an organic polymer binder. The binder is preferably a thermoplastic resin, for example, acrylic acid, methacrylic acid,
Acrylic esters, homopolymers of acrylic monomers such as methacrylic esters and copolymers thereof, methyl cellulose, ethyl cellulose, cellulose polymers such as cellulose acetate, polystyrene, polyvinylpyrrolidone, polyvinyl butyral, polyvinyl alcohol, polyvinyl chloride, etc. And homopolymers and copolymers of vinyl monomers such as polyesters, 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) lower than 90 ° C. in order to obtain a proper adhesive strength with the image forming layer. For this purpose, it is also 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 sheets. The binder polymer of the image receiving layer is the same as the binder polymer of the image forming layer, in that the adhesiveness with the image forming layer during laser recording is improved, and the sensitivity and the image strength are improved.
Or it is particularly preferable to use a similar polymer.

The smoother value of the surface of the image receiving layer is 23 ° C., 55% R
Preferably, H is 0.5 to 50 mmHg (≒ 0.0665 to 6.65 kPa), and Ra is preferably 0.05 to 0.4 μm. Micro gaps can be reduced, transfer,
Further, 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 the image receiving sheet is charged according to the US Federal Government Test Standard 4046, the charging potential of the image receiving layer 1 second after the image receiving sheet is grounded is preferably -100 to 100 V. It is preferable that the surface resistance of the image receiving layer is 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 0.8 or less. The surface energy of the surface of the image receiving layer is preferably 23 to 35 mg / m ² .

In the case where an image is once formed on the image receiving layer and then retransferred to printing paper or the like, at least one of the image receiving layers is preferably formed from a photocurable material. Examples of the composition of such a photocurable material include a) a photopolymerizable monomer comprising at least one of a polyfunctional vinyl or vinylidene compound capable of forming a photopolymer by addition polymerization;
Examples of the combination include b) an organic polymer, c) a photopolymerization initiator, and if necessary, additives 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 polymer for forming an image receiving layer. As the photopolymerization initiator, a general photoradical polymerization initiator such as benzophenone and Michler's ketone is used in a ratio 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 at the time of retransfer to the printing paper, and the film is easily broken. If the thickness is too large, the gloss of the image after the re-transfer of the paper increases, and the closeness to the printed matter decreases.

(Other Layers) Between the support and the image receiving layer,
A cushion layer may be provided. By providing a cushion layer, the adhesion between the image forming layer and the image receiving layer can be improved during laser thermal transfer, and the image quality can be improved. Further, at the time of recording, even if foreign matter is mixed between the thermal transfer sheet and the image receiving sheet, the gap between the image receiving layer and the image forming layer is reduced due to the deformation action of the cushion layer, and as a result, the size of image defects such as white spots is reduced. You can also. Further, 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 that the transferability of the image receiving layer can be improved, and By reducing the gloss of the object, the similarity with the printed matter can be improved.

The cushion layer is easily deformed when a stress is applied to the image receiving layer. To achieve the above effect, a material having a low modulus of elasticity, a material having rubber elasticity, or easily softened by heating. It is preferred to be 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, and more preferably 10 to 100 GPa.
MPa. In addition, in order to allow foreign matter such as dust to be sunk, the penetration (25
(C, 100 g, 5 seconds) is preferably 10 or more. Further, the glass transition temperature of the cushion layer is 80 ° C. or less, preferably 25 ° C. or less, and the softening point is preferably 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 a binder for 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. Copolymer, ethylene-vinyl acetate copolymer, ethylene-acryl copolymer, vinyl chloride-vinyl acetate copolymer, vinylidene chloride resin, vinyl chloride resin containing a plasticizer, polyamide resin, phenol resin and the like. The thickness of the cushion layer varies depending on the resin used and other conditions.
Preferably it is 10 to 52 μm.

The image receiving layer and the cushion layer need to be adhered to each other up to the stage of laser recording, but are preferably provided so as to be peelable in order to transfer an image to the printing paper. In order to facilitate peeling, it is 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 thickness depending on 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, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, polyvinyl alcohol, and polyvinyl chloride. , Urethane resin,
Tg of fluorine-based resin, styrenes such as polystyrene and acrylonitrile styrene and those obtained by crosslinking these resins, polyamide, polyimide, polyetherimide, polysulfone, polyethersulfone, and aramid have a Tg of 65 ° C.
The above-mentioned thermosetting resins and cured products of these resins are included. As the curing agent, a general curing agent such as isocyanate and melamine can be used.

When a binder for the release layer is selected in accordance with the above physical properties, polycarbonate, acetal and ethyl cellulose are preferred in terms of preservability. Further, when an acrylic resin is used for the image receiving layer, the resin is peeled off when the image after laser thermal transfer is retransferred. It is particularly preferable because the properties are good. Separately, a layer having extremely low adhesiveness to the image receiving layer upon cooling can be used as the release layer. Specifically, a layer mainly composed of a heat-fusible compound such as a wax or a binder or a thermoplastic resin can be used. Examples of the heat-fusible compound include 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, an ethylene copolymer such as an ethylene-vinyl acetate resin, a cellulose resin, or the like is preferably used.

As needed, higher fatty acids, higher alcohols, higher fatty acid esters, amides, higher amines and the like can be added to such a release layer.
Another configuration of the release layer is a layer having a releasability by melting or softening upon heating to cause cohesive failure itself. Preferably, such a release layer contains a supercooled substance. Examples of the supercooled substance include poly-ε-caprolactone, polyoxyethylene, benzotriazole, tribenzylamine, and vanillin. Further, the peelable layer having another structure contains a compound that reduces the adhesiveness to the image receiving layer. 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; Solid waxes such as waxes and amide waxes; and fluorine-based and phosphate-based surfactants. As a method of forming the release layer,
A material obtained by dissolving the material in a solvent or dispersing in a latex state is a blade coater, a roll coater, a bar coater,
A coating method such as a curtain coater or a gravure coater, an extrusion lamination method using a hot melt, or the like can be applied, and can be formed by coating on a cushion layer. Alternatively, there is a method in which a material obtained by dissolving or dispersing the material in a solvent or in the form of latex on a temporary base is applied by the above-described method and bonded to a cushion layer, 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 this case, the image receiving sheet may be a support / cushion image receiving layer or a support / undercoat layer. / Cushioning image receiving layer may be used. Also in this case, it is preferable that the cushioning image-receiving layer is provided in a releasable manner so that the image can be retransferred to the printing paper. In this case, the image after retransfer to the printing paper becomes an image having excellent gloss. The thickness of the cushioning image receiving layer is 5 to 100 μm, preferably 10 to 100 μm.
４０40 μm.

It is preferable to provide a back layer on the surface of the support opposite to the surface on which the image receiving layer is provided, since the transportability of the image receiving sheet is improved. It is preferable to add an antistatic agent such as a surfactant and tin oxide fine particles and a matting agent such as silicon oxide and PMMA particles to the back layer in terms of improving the transportability in the recording apparatus. The additives can be added not only to the back layer but also to the image receiving layer and other layers as needed. Although the type of additive cannot be specified unconditionally depending on the 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, it can be appropriately selected and used from various surfactants and conductive agents.

The binder used in the back layer includes gelatin, polyvinyl alcohol, methyl cellulose, nitrocellulose, acetyl cellulose, aromatic polyamide resin, silicone resin, epoxy resin, alkyd resin, phenol resin, melamine resin, fluorine resin, and 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 compounds, aromatic esters, fluorinated polyurethane A general-purpose polymer such as polyether sulfone can be used. Cross-linking using a cross-linkable water-soluble binder as the binder for the back layer is effective in preventing the matting agent from falling off and improving the scratch resistance of the back layer. It is also highly effective in blocking during storage. This crosslinking means can be selected without particular limitation on any one or combination of heat, actinic rays, and pressure, depending on the properties of the crosslinking agent used. 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 a matting agent preferably added to the back layer, organic or inorganic fine particles can be used. As an organic matting agent, polymethyl methacrylate (PMM
A), polystyrene, polyethylene, polypropylene,
Other examples include fine particles of a radical polymerizable polymer, and fine particles of a condensation polymer such as polyester and polycarbonate. The back layer is preferably provided with a coverage of about 0.5 to 5 g / m ² . If it is less than 0.5 g / m ² , the coating properties are unstable and problems such as powder dropping of the matting agent are likely to occur.
Further, when the coating is applied more than 5 g / m ² , the particle size of the suitable matting agent becomes very large, and the image receiving layer surface is embossed by the back layer during storage, and especially the thermal transfer for transferring the thin image forming layer. In this case, missing or unevenness of a recorded image is likely to occur. The matting agent preferably has a number average particle size that is larger by 2.5 to 20 μm than the layer thickness of the binder alone of the back layer. Among the matting agents, particles having a particle size of 8 μm or more need 5 mg / m ² or more, and preferably 6 to 600 mg / m ^2.
a m ^2. This improves, in particular, foreign object failure.
The value σ / r is obtained by dividing the standard deviation of the particle size distribution by the number average particle size.
By using a material having a narrow particle size distribution such that n (= coefficient of variation of the particle size distribution) is 0.3 or less, defects caused by particles having an abnormally large particle size can be improved.
Desired performance can be obtained with a smaller amount of addition. This coefficient of variation is more preferably 0.15 or less.

It is preferable to add an antistatic agent to the back layer in order to prevent adhesion of foreign matter due to frictional charging with the transport roll. Examples of the antistatic agent include cationic surfactants, anionic surfactants, nonionic surfactants, polymer antistatic agents, conductive fine particles, and “1129”.
Compounds described in Chemical Industry No. 0, pp. 875-876, etc. are widely used. As the antistatic agent that can be used in combination with the back layer, among the above substances, conductive fine particles such as carbon black, metal oxides such as zinc oxide, titanium oxide and tin oxide, and organic semiconductors are preferably used. In particular, the use of conductive fine particles is preferable because the antistatic agent does not dissociate from the back layer and a stable antistatic effect can be obtained regardless of the environment. In addition, the back layer, in order to impart coating properties and release properties, various activators,
It is also possible to add a release agent such as silicone oil or fluorine-based resin. The back layer is particularly preferable when the softening points of the cushion layer and the image receiving layer as measured by TMA (Thermomechanical Analysis) are 70 ° C. or less.

The TMA softening point is determined by raising the temperature of an object to be measured at a constant heating rate while applying a constant load, and observing the phase of the object. In the present invention, the TMA softening point is defined as the temperature at which the phase of the measurement object starts to change. 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 overlapped. 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 and heating roller. The heating temperature in this case is preferably 160 ° C. or lower, or 130 ° C. or lower.

As another method for obtaining a laminate, the above-mentioned vacuum contact method is also suitably used. In the vacuum contact method, first, an image receiving sheet is wound on a drum provided with a suction hole for evacuation, and then a thermal transfer sheet slightly larger than the image receiving sheet is pressed while uniformly extruding air with a squeeze roller. This is a method in which the substrate is brought into close contact with a vacuum. As another method, there is a method in which an image-receiving sheet is mechanically attached to a metal drum while being pulled, and a thermal transfer sheet is similarly attached to the metal drum while being mechanically pulled and adhered. Among these methods, the vacuum adhesion method is particularly preferable because temperature control of a heat roller or the like is not required and lamination can be performed quickly and uniformly.

[0119]

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

(Example 1)-Preparation of thermal transfer sheet (magenta)-[Formation of back layer] [Preparation of coating solution for back first layer] Aqueous dispersion of acrylic resin 2 parts (Jurimar ET410, solid content 20% by mass) , Manufactured by Nippon Junyaku Co., Ltd. Antistatic agent (water dispersion of tin oxide-antimony oxide) 7.0 parts (average particle size: 0.1 μm, 17% by mass) Polyoxyethylene phenyl ether 0.1 part Melamine Compound 0.3 part (Sumitic Resin M-3, manufactured by Sumitomo Chemical Co., Ltd.) Distilled water was prepared so that the total would be 100 parts. [Formation of Back First Layer] Polyethylene terephthalate biaxially stretched with a thickness of 75 μm Support (Ra on both sides is 0.01μ)
m) is subjected to a corona treatment on one side (back side),
After applying the one-layer coating solution so that the dry layer thickness is 0.03 μm
After drying at 180 ° C. for 30 seconds, the first bag layer was formed. The Young's modulus of the support in the longitudinal direction is 450 kg / mm ² (≒ 4.
4 GPa) and the Young's modulus in the width direction is 500 kg / mm ^2.
(≒ 4.9 GPa). F-5 in the longitudinal direction of the support
The value was 10 kg / mm ² (≒ 98 MPa), and the F-5 value in the support width direction was 13 kg / mm ² (≒ 127.4 MPa).
The heat shrinkage of the support at 100 ° C. for 30 minutes is 0.3% in the longitudinal direction and 0.1% in the width direction. The breaking strength is 20 kg / mm ² (≒ 196 MPa) in the longitudinal direction.
The width direction is 25 kg / mm ² (≒ 245 MPa), and the elastic modulus is 400 kg / mm ² (≒ 3.9 GPa).

[Preparation of Back Layer Second Layer Coating Solution] Polyolefin 3.0 parts (Chemipearl S-120, 27% by mass, manufactured by Mitsui Petrochemical Co., Ltd.) Antistatic agent (tin oxide-antimony oxide aqueous dispersion) 2.0 parts (average particle size: 0.1 μm, 17% by mass) Colloidal silica 2.0 parts (Snowtex C, 20% by mass, manufactured by Nissan Chemical Co., Ltd.) Epoxy compound 0.3 part (Dinacol EX- 614B, manufactured by Nagase Kasei Co., Ltd.) Distilled water was prepared so that the total amount would be 100 parts. 170 ℃ after applying
For 30 seconds to form a back second layer.

1) Preparation of Coating Solution for Light-to-Heat Conversion Layer The following components were mixed while stirring with a stirrer to prepare a coating solution for a light-to-heat conversion layer. [Coating liquid composition for photothermal conversion layer]-Infrared absorbing dye 10 parts ("NK2014", a cyanine dye having the following structure, manufactured by Hayashibara Biochemical Laboratory Co., Ltd.)

[0123]

Embedded image

(Wherein, R represents CH ₃ and X ⁻ represents ClO ₄ ⁻ ). 40 parts of vinyl chloride / vinyl acetate copolymer (“Solvain CL”, manufactured by Nissin Chemical Co., Ltd.) • Methyl ethyl ketone ( MEK) 2000 parts ・ Surfactant 1 part (“MegaFac F-176P”, manufactured by Dainippon Ink and Chemicals, F-based surfactant) ・ Matting agent 2 parts )

2) Formation of a light-to-heat conversion layer on the surface of a support After the above-mentioned coating solution for a light-to-heat conversion layer was applied on the absorption layer using a wire bar, the coating was dried in an oven at 100 ° C. for 2 minutes. Thus, a light-to-heat conversion layer was formed on the support. The obtained light-to-heat conversion layer has an absorption at a wavelength of about 808 nm, and its absorbance (optical density: OD) is measured by using a Shimadzu UV.
OD = measured with a spectrophotometer UV-240
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 magenta image forming layer The following components were prepared using a paint shaker (Toyo Seiki Co., Ltd.)
), And the glass beads were removed to obtain a pigment-dispersed mother liquor. [Magenta pigment dispersion mother liquor composition]-12.6 parts of polyvinyl butyral ("ESLEC BLSH", manufactured by Sekisui Chemical Co., Ltd.)-Pigment Red (Pigment Red) 57: 1 (CI No. 1 5850: 1) 15 0.0 parts (“Symler Brilliant Carmine 6B-229”, manufactured by Dainippon Ink and Chemicals, Inc.) ・ Dispersion aid 0.6 parts (“Solsperse S-20000”, manufactured by ICI Corporation) -79.4 parts of n-propyl alcohol

Using the pigment-dispersed mother liquor, the following materials were added while stirring with a stirrer to prepare a magenta image forming layer coating solution. [Composition of magenta image forming layer coating solution]-163 parts of the above-mentioned magenta pigment-dispersed mother liquor-8.6 parts of polyvinyl butyral ("ESLEC BLSH", manufactured by Sekisui Chemical Co., Ltd.)-Wax compound (stearic amide "Neutron 2" 1.0 part (behenamide "Diamid BM", Nippon Kasei Co., Ltd.) 1.0 part (lauric amide "Diamid Y", Nippon Kasei Co., Ltd.) 1.0 part (palmitic acid amide “Diamid KP”, manufactured by Nippon Kasei Co., Ltd.) 1.0 part (erucic acid amide “Diamind L-200”, manufactured by Nippon Kasei Co., Ltd.) 1.0 part ( 3. Oleic acid amide “Diamid O-200”, manufactured by Nippon Kasei Co., Ltd. 1.0 part ・ Nonionic surfactant 0.7 parts (“Chemistat 1100”, manufactured by Sanyo Chemical Co., Ltd.) ・ Rosin 4. 6 parts ("KE-311", manufactured by Arakawa Chemical Co., Ltd.) (Ingredients: resin acid 80-97%; resin acid components abietic acid 30-40%, neoabietic acid 10-20% dihydroabietic acid 14%, tetrahydro -Abietic acid 14%)-2.5 parts of pentaerythritol tetraacrylate ("NK ester A-TMMT", manufactured by Shin-Nakamura Chemical Co., Ltd.)-1.3 parts of surfactant ("Megafac F-176P", solid content) 20%, manufactured by Dainippon Ink and Chemicals, Inc.) n-propyl alcohol 1000 parts The particles in the obtained coating solution for the magenta image forming layer were measured using a laser scattering type particle size distribution analyzer to find the average particle size. The diameter was 0.25 μm, and the ratio of particles having a diameter of 1 μm or more was 0.5%.

4) Formation of magenta image forming layer on the surface of light-to-heat conversion layer The above-mentioned coating solution for magenta image-forming layer was coated on the surface of the light-to-heat conversion layer for 1 minute using a wire bar, and then the coated material was heated to 100 ° C. After drying in an oven for 2 minutes, a magenta image forming layer was formed on the light-to-heat conversion layer. The optical density (optical density: OD) of the magenta image forming layer of the thermal transfer sheet is
It was OD = 0.91 when measured by Macbeth densitometer "TD-904" (W filter). When the thickness of the magenta image forming layer was measured, the average was 0.4 m.
Met.

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

(Example 2) The vinyl chloride / vinyl acetate copolymer of the coating composition for the photothermal conversion layer of Example 1 was changed to polymethyl methacrylate ("Dianal BR88", manufactured by Mitsubishi Rayon Co., Ltd.). Except for the above, a thermal transfer sheet was prepared in the same manner as in Example 1.

Example 3 A thermal transfer sheet was prepared in the same manner as in Example 1, except that the composition of the coating solution for the photothermal conversion layer in Example 1 was changed as follows. -10 parts of carbon black dispersion ("MHI # 201", manufactured by Mikuni Color Co., Ltd.)-40 parts of vinyl chloride / vinyl acetate copolymer ("Solvain CL", manufactured by Nissin Chemical Co., Ltd.)-Methyl ethyl ketone (MEK) 2000 parts)-1 part of surfactant ("Megafac F-176P", manufactured by Dainippon Ink and Chemicals, F-based surfactant)-2 parts of matting agent ("Seahoster KEP150": silica particles Nippon Shokubai Co., Ltd.) Made)

Comparative Example 1 A light-to-heat conversion layer was formed in the same manner as in Example 1. Thereafter, a coating liquid for a magenta image forming layer having the following composition was prepared and applied in the same manner as in Example 1 to prepare a thermal transfer sheet. -1260 parts of distilled water-26 parts of polyvinyl alcohol ("PVA205", manufactured by Kuraray Co., Ltd.)-100 parts of magenta pigment dispersion ("High Micron GA Magenta 1", manufactured by Mikuni Pigment Co., Ltd.)

Comparative Example 2 A thermal transfer sheet was prepared in the same manner as in Example 1 except that the composition of the coating solution for the photothermal conversion layer in Example 1 was changed as follows.・ 3500 parts of water ・ 60 parts of polyvinyl alcohol (“PVA-C118”, manufactured by Kuraray Co., Ltd.) ・ 17 parts of water-soluble infrared absorbing dye (“NK-3261”, manufactured by Hayashibara Biochemical Laboratory Co., Ltd.) ・ Mat 2 parts ("Sea Hostar KEP150": silica particles manufactured by Nippon Shokubai Co., Ltd.)

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

2) Coating solution for image receiving layer-10 parts of polyvinyl butyral ("ESLEC B BL-SH", manufactured by Sekisui Chemical Co., Ltd.)-0.7 parts of antistatic agent ("Sunstat 2012A", Sanyo Chemical Industries, Ltd.)・ Surfactant 1.0 part (“MegaFac F-176P”, manufactured by Dainippon Ink & Chemicals, Inc.) ・ n-propyl alcohol 500 parts ・ Methanol 20 parts ・ 1-methoxy-2- 50 parts of propanol

Using a small width applicator, a white PET support (“Lumirror # 130E58”, manufactured by Toray Industries, Inc., thickness 1)
00 μm), the above coating liquid for forming a cushion layer is applied, the coating layer is dried, and then the coating liquid for an image receiving layer is applied.
Dried. The thickness of the cushion layer after drying is about 20 μm,
The coating amount was adjusted so that the 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 titanium oxide-containing polyethylene terephthalate layers (thickness: 7 μm, titanium oxide content: 2%) provided on both sides thereof. (Total thickness: 130 μm, specific gravity: 0.8) is a void-containing plastic support. The produced material was wound up in a roll form, stored for 1 week at room temperature, and then used for image recording with the following laser beam.

The physical properties of the obtained image receiving layer were as follows. Surface roughness Ra is preferably 0.4 to 0.01 μm,
Specifically, it was 0.02 μm. The undulation of the surface of the image receiving layer is preferably 2 μm or less, specifically 1.2 μm. The smoother value of the surface of the image receiving layer is 23 ° C., 55%
0.5 to 50 mmHg at RH ($ 0.0665 to 6.6)
5 kPa), specifically, 0.8 mmHg (≒
0.11 kPa). The coefficient of static friction of the surface of the image receiving layer is preferably 0.8 or less, and specifically 0.37.

(Image Receiving Sheet 2) An image receiving sheet was prepared in the same manner except that the composition of the coating solution for the image receiving layer of the image receiving sheet 1 was changed to the following composition. -10 parts of polyvinyl alcohol ("PVA205", manufactured by Kuraray Co., Ltd.)-500 parts of distilled water

(Image receiving sheet 3) An image receiving sheet was prepared in the same manner except that the composition of the coating solution for the image receiving layer of the image receiving sheet 1 was changed to the following composition. -Vinyl chloride / vinyl acetate copolymer 10 parts ("Solvain CL", manufactured by Nissin Chemical Co., Ltd.)-Antistatic agent 0.7 parts ("Sunstat 2012A", manufactured by Sanyo Chemical Industries, Ltd.)-Interface Activator 1.0 part ("MegaFac F-176P", manufactured by Dainippon Ink and Chemicals, Inc.) 500 parts of n-propyl alcohol 20 parts of methanol 50 parts of 1-methoxy-2-propanol

-Formation of Transfer Image- Using the thermal transfer sheets and the image receiving sheets 1 to 3 of Examples 1 to 3 and Comparative Examples 1 and 2, transfer images were formed as follows. As the image receiving sheet to be combined with each thermal transfer sheet, a sheet formed using the same resin as the resin contained in the image forming layer of the thermal transfer sheet was selected. 40 cm diameter with 1 mm diameter vacuum section holes (one area density in 3 cm x 8 cm area)
The image receiving sheet (56 cm × 79 cm) was wound around the rotary drum and vacuum-adsorbed. Then, 61cm x 84c
The thermal transfer sheets cut into m were overlapped so as to evenly protrude from the image receiving sheet, and squeezed with a squeeze roller, and adhered and laminated so that air was sucked into the section holes. The degree of decompression with the section hole closed is
-150mmHg (@ 81.13kP for 1 atm)
a). The drum is rotated, and a semiconductor laser beam having a wavelength of 808 nm is condensed from the outside onto 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. The laser image (image) was recorded on the laminate while moving in the direction perpendicular to the scanning direction) (sub-scanning). Laser irradiation conditions are as follows. The laser beam used in this embodiment was a multi-beam two-dimensional laser beam consisting of five parallel lines in the main scanning direction and three parallel lines in the sub-scanning direction. Laser power 300 mW Main scanning speed 5 m / sec Sub-scanning pitch 6.35 μm The diameter of the exposure drum is preferably 360 mm or more, specifically, 380 mm. The image size is 51
5 mm x 728 mm, resolution is 2600 dpi.
When the laminated body after the laser recording was completed was removed from the drum and the thermal transfer sheet 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 was transferred from the thermal transfer sheet to the image receiving sheet. Was confirmed.

-Evaluation- Humidity dependence The recording environment was set to 23 ° C. 30% RH and 23 ° C. 70% RH, and Luxel Final Proof 5600 (Fuji Photo Film Co., Ltd.)
Manufactured at 50% flat screen at a resolution of 2438 dpi. The density of the recorded image was measured using X-Rite938 (manufactured by X-Rite). The density difference depending on the humidity is as shown in Table 1 below.

[0142]

[Table 1]

Incidentally, the SP value of each solvent is described in the Polymer Handbook.
3 with reference to the ^rd edition VII / 526-539.

It can be seen that the recorded image using the thermal transfer sheet of the present invention has a small density difference due to humidity and is excellent in humidity dependency.

[0145]

The thermal transfer recording material of the present invention is hardly affected by humidity and can obtain a thermal transfer recorded image without depending on the humidity at the time of recording. Further, a multicolor image forming method which is less affected by humidity can be provided by the laser thin film thermal transfer method using the thermal transfer recording material of the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a mechanism of forming a multicolor image by thin-film thermal transfer using a laser.

FIG. 2 is a diagram illustrating a configuration example of a recording apparatus for laser thermal transfer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 recording apparatus 2 recording head 3 sub-scanning rail 4 recording drum 5 thermal transfer sheet loading unit 6 image receiving sheet roll 7 transport roller 8 squeeze roller 9 cutter 10 thermal transfer sheet 10K, 10C, 10M, 10Y thermal transfer sheet roll 12 support 14 photothermal conversion layer Reference Signs List 16 image forming layer 20 image receiving sheet 22 support for image receiving sheet 24 image receiving layer 30 laminated body 31 discharge table 32 waste port 33 discharge port 34 air 35 waste box

Claims (13)

[Claims] 1. A thermal transfer recording material having a light-to-heat conversion layer containing at least a light-to-heat conversion substance and a resin on a support and an image-forming layer containing a pigment and a resin in this order. A thermal transfer recording material used for recording a high-resolution image of 2400 dpi or more, characterized in that a water-insoluble resin is used for both resins. 2. The thermal transfer recording material according to claim 1, wherein the resin contained in the light-to-heat conversion layer is dissolved in a hydrophobic solvent having an SP value of 16 to 22. 3. The thermal transfer recording material according to claim 1, wherein the resin contained in the image forming layer is dissolved in a non-aqueous solvent having an SP value of 16 to 30. 4. The method according to claim 1, wherein a hydrophobic solvent is used as a solvent for dissolving the resin when the photothermal conversion layer is provided, and a non-aqueous solvent is used as a solvent for dissolving the resin when the image forming layer is provided. 4. The thermal transfer recording material according to any one of items 1 to 3. 5. The photothermal conversion material of the photothermal conversion layer in a coating solvent for forming the image forming layer has a solubility of 1 wt% or less. Thermal transfer recording material. 6. The thermal transfer according to claim 1, wherein the solubility of the resin of the light-to-heat conversion layer in a coating solvent for forming the image forming layer is 1 wt% or less. Recording material. 7. The method according to claim 1, wherein the resin of the light-to-heat conversion layer has a solubility of 0.1 wt% or more in a coating solvent for forming the light-to-heat conversion layer. Thermal transfer recording material. 8. The thermal transfer recording according to claim 1, wherein the solubility of the photothermal conversion substance in a coating solvent for forming the photothermal conversion layer is 0.1 wt% or more. material. 9. The thermal transfer recording material according to claim 1, wherein said photothermal conversion material is an infrared absorbing dye. 10. The method according to claim 1, wherein the resin of the image forming layer has a solubility of 0.1 wt% or more in a coating solvent for forming the image forming layer. Thermal transfer recording material. 11. The thermal transfer recording material according to claim 1, wherein an intermediate layer is provided between the light-to-heat conversion layer and the image forming layer. 12. The method according to claim 1, wherein the thermal transfer recording material is formed by successive coating. 13. An image receiving material having an image receiving layer and a thermal transfer recording material having at least a light-to-heat conversion layer and an image forming layer on a support, wherein the image forming layer of the thermal transfer recording material and the image receiving layer of the image receiving sheet are combined. In a multicolor image forming method having a step of irradiating light from the support side of the thermal transfer recording material and irradiating the light irradiation area of the image forming layer onto the image receiving layer of the image receiving sheet and recording the image, A multicolor image forming method using the thermal transfer recording material according to claim 1.