JP4734380B2 - Color filter forming method and color filter - Google Patents

Description

  The present invention relates to a method for forming a color filter and a color filter. The present invention particularly relates to formation of a high resolution color filter using a laser thermal transfer sheet.

A color filter used for a liquid crystal display or the like is produced using a photosensitive transfer material.
The principle of creating a color filter is based on the formation of a multicolor image of a photosensitive transfer material. An image forming method using this photosensitive transfer material will be described.
The photosensitive resin layer is bonded onto the substrate under pressure and heating, and then the temporary support is peeled off, exposed through a predetermined mask or the like (in some cases, a thermoplastic resin layer or an intermediate layer), and then developed. . Development is performed by immersing in a solvent or aqueous developer, particularly an alkaline aqueous solution, or spraying the developer from a spray by a known method, and further by rubbing with a brush or irradiating with ultrasonic waves. . By using a photosensitive transfer material having a photosensitive resin layer colored in a different color and repeating this process a plurality of times, a multicolor image can be formed.
In recent years, with the progress of OA, copying machines, printers, and the like using various recording methods such as an electrophotographic method, an ink jet method, a thermal transfer recording method, and the like are used in accordance with each application. Among these, the thermal transfer recording system has advantages such as easy operation and maintenance, miniaturization of the apparatus, and cost reduction, and therefore, it can be applied to color filter forming materials. It is being made.
In the thermal transfer recording system, for example, a recording system for producing a color proof directly from a digital signal has been developed along with the popularization of an electronic system in a recent pre-printing process (prepress field). Such an electronic system is particularly intended to produce a high-quality color proof, and generally reproduces a dot image of 150 lines / inch or more. In order to record a high-quality proof from a digital signal, a laser beam that can be modulated by the digital signal and can narrow down the recording light is used as a recording head. For this reason, it is necessary to develop a recording material that exhibits high recording sensitivity with respect to laser light and exhibits high resolving power that enables reproduction of high-definition halftone dots.

  As a recording material used in a transfer image forming method using laser light, on a support, a light-to-heat conversion layer that absorbs laser light to generate heat, and a pigment is a component such as a heat-meltable wax or binder. A heat-melt transfer sheet (Patent Document 1) having an image forming layer dispersed in this order is known. In the image forming method using these recording materials, the image forming layer corresponding to the region is melted by the heat generated in the laser light irradiation region of the light-to-heat conversion layer and transferred onto the image receiving sheet laminated on the transfer sheet. Then, a transfer image is formed on the image receiving layer.

  Patent Document 2 discloses a photothermal conversion layer containing a photothermal conversion substance, a very thin layer (0.03 to 0.3 μm) of a heat release layer, and an image forming layer containing a coloring material in this order on a support. A thermal transfer sheet provided is disclosed. In this thermal transfer sheet, by irradiating the laser beam, the bonding force between the image forming layer and the photothermal conversion layer bonded by 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”. Specifically, the thermal peeling layer is partially decomposed and vaporized in the region irradiated with the laser beam. In this method, 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.

These image forming methods can use printing paper provided with an image receiving layer (adhesive layer) as an image receiving sheet material, and can easily obtain multicolor images by transferring images of different colors onto the image receiving sheet one after another. In particular, an image forming method using ablation has an advantage that a high-definition image can be easily obtained, and is color proof (DDCP: direct digital color proof) or high-definition. It is useful for producing a simple mask image.

The laser thermal transfer multicolor image forming material used in the DDCP technique is useful as a color filter forming material.
The color filter has a structure in which R, G, and B stripe-like images or dot-like images, that is, pixels are arranged on a transparent image-receiving sheet, and each boundary is usually divided by a black matrix.
The pixels and the black matrix require a higher optical density than the color proof, and as a result, the thickness of the pixels and the black matrix must be increased.
However, if the image forming layer of the thermal transfer sheet is increased in order to increase the layer thickness, the transferability of the pixel to the image receiving sheet is deteriorated, the edge shape of the pixel is deteriorated, and a step is generated between the pixel and the black matrix. There was a bug.

JP-A-5-58045 Japanese Patent Laid-Open No. 6-219052

  An object of the present invention is to provide a color filter forming method capable of providing a color filter having a good edge shape, no step, and a high optical density, and a color filter obtained thereby.

That is, the means for solving the above problems are as follows.
(1) Four types of laser thermal transfer sheets having a photothermal conversion layer containing at least a polyimide resin as a binder and a red (R), green (G), blue (B) or black (K) image forming layer on a support. the image-receiving sheet and thereby superimposing, R to transfer the image forming layer on the image receiving sheet by irradiating a laser beam to imagewise from the thermal transfer sheet side, a method of forming an image consisting of G, B and K A method for forming a color filter, wherein at least one of the four types of laser thermal transfer sheets is transferred twice or more.
(2) The method for forming a color filter as described in (1) above, wherein the image forming layer of the laser thermal transfer sheet having the K image forming layer is transferred first and last.
(3) The method for forming a color filter as described in (1) or (2) above, wherein the thickness of the image forming layer is from 0.1 to 5 μm.
(4) A color filter produced by the method for forming a color filter described in any one of (1) to (3) above.

  According to the present invention, since a laser thermal transfer sheet is used, a large size (A2 / B2) color filter can be provided inexpensively and accurately. Further, even when recording is performed with laser beams that are multi-beam two-dimensional arrays under different temperature and humidity conditions, the images (R, G, B, K) are good, and the level difference of the edge shape is good with high optical density. It is possible to provide a color filter having an image (R, G, B, K) having no image.

In the color filter forming method of the present invention, a process of transferring an image onto an image receiving sheet by irradiating an image forming layer with laser light imagewise from the thermal transfer sheet side is carried out in red (R), green (G), blue (B Or at least one of four types of laser thermal transfer sheets having a black (K) image forming layer is used twice or more.
In the present invention, an image composed of R, G, B, and K is formed on the image receiving sheet by the above method. Here, in the image composed of R, G, B, and K, the red filter pixel (R), the green filter pixel (G), and the blue filter pixel (B) are filled between the black matrix of the color filter. The set of these pixels and the black matrix is referred to as an image (R, G, B, K). A set of pixels is referred to as a pixel (R, G, B).
Examples of the color filter image (R, G, B, K) include an arrangement of a black matrix and pixels (R, G, B) as shown in FIG. 3, but are not limited thereto. Is optional. As for the size of the pixel (R), the pixel (G), and the pixel (B), for example, in the figure, a is about 100 to 300 μm, b is about 300 μm, and the black matrix line width of c is about several μm to 20 μm. However, it can be changed as appropriate.
The color filter must be formed on the image receiving sheet with no gap between the pixels (R, G, B) and the black matrix as described above.
In the present invention, images (R, G, B, K) can be formed with high accuracy by transferring at least one of four types of laser thermal transfer sheets having a relatively thin image forming layer a plurality of times.
As described above, the black matrix is produced in the gaps in which the pixels (R, G, B) are formed, or in the reverse order. However, when using a laser thermal transfer sheet, the latter should be used first to ensure transferability. In this case, it is preferable to transfer again by a laser thermal transfer sheet of K at the end.

The method for forming this image (R, G, B, K) is not particularly limited, but the following method is exemplified.
First, a black matrix is formed using a thermal transfer sheet having a thickness of K1, and then sequentially transferred using each of the thermal transfer sheets of R2, G2 and B2 having an image forming layer having a thickness larger than the thickness of the black matrix. R2, G2, B2, K1) is formed, and the image transfer layer thickness of K is set so that the thickness is the same as that of the pixels (R2, G2, B2) on the image (R2, G2, B2, K1). A flat image (R2, G2, B2, K2) can be formed by transfer using a sheet.
Alternatively, a black matrix is first formed using a thermal transfer sheet having a thickness of K1, and then sequentially transferred using each of the thermal transfer sheets of R1, G1, and B1 having an image forming layer having the same thickness as that of the black matrix, An image (R1, G1, B1, K1) is formed, and a black matrix is laminated on the black matrix of the image (R1, G1, B1, K1) using a thermal transfer sheet having a thickness of K1, and then the black matrix A flat image (R2, G2, B2, K2) can be formed by sequentially transferring using R1, G1, and B1 thermal transfer sheets each having an image forming layer having the same thickness as the thickness.
In the above method, the order of transfer of the four types of laser thermal transfer sheets can be appropriately changed.

  In the method of the present invention, since a thermal transfer sheet having a relatively thin image forming layer can be used, a pixel and / or a black matrix formed by breaking the image forming layer of the laser irradiation corresponding portion into pieces is laminated. As a result, the edge shape can be formed at a right angle, and a color filter of an image (R, G, B, K) having a high optical density and no step can be formed.

The laser thermal transfer sheet used in the present invention is effective and suitable for a system that realizes a thermal transfer image with sharp halftone dots and enables B2 size recording (515 mm × 728 mm, where B2 size is 543 mm × 765 mm).
This thermal transfer image can be a halftone dot image corresponding to the number of printed lines at a resolution of 2400 to 2540 dpi. Each halftone dot has almost no blurring or chipping, and the shape is very sharp, so a high range of halftone dots from highlight to shadow can be clearly formed. As a result, it is possible to output a high-quality halftone dot with the same resolution as that of the image setter or CTP setter, and to reproduce a halftone dot having good closeness to the set value and to display the halftone dot in the image (R, G, B, K).

This thermal transfer image has a sharp halftone dot shape, so it can faithfully reproduce halftone dots and pixels corresponding to the laser beam, and the recording temperature has very little dependence on the environment temperature and humidity. Under these conditions, it is possible to obtain stable repeatability in both hue and density.
Since this thermal transfer image has good reproducibility, a highly accurate CMS (Color Management System) can be realized.

In addition, since this thermal transfer image has a sharp dot shape, the pixels can be reproduced clearly. The heat generated by the laser beam is transmitted to the transfer interface without diffusing in the surface direction, and the image forming layer is sharply broken at the interface between the heating part and the non-heating part. For this purpose, the thickness of the photothermal 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 photothermal conversion layer instantaneously reaches about 700 ° C., and if the film is thin, it is likely to be deformed or broken. When the deformation / destruction occurs, the photothermal conversion layer is transferred onto the image receiving sheet together with the transfer layer, or the transfer image becomes non-uniform. On the other hand, in order to obtain a predetermined temperature, the photothermal conversion substance must be present in a high concentration in the film, and problems such as pigment precipitation and migration to an adjacent layer also occur.
For this reason, it is preferable to reduce the thickness of the photothermal conversion layer to about 0.5 μm or less by selecting a heat-resistant binder such as an infrared absorbing dye having excellent photothermal conversion characteristics and polyimide.

In general, when the light-to-heat conversion layer is deformed or 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. R, G, B, K) become non-uniform and the apparent transfer density decreases. This tendency is more conspicuous as the image forming layer is thinner. On the other hand, if the thickness of the image forming layer is large, the sharpness of the dots is impaired and the sensitivity is also lowered.
In order to achieve both of these conflicting performances, it is preferable to improve transfer unevenness by adding a low melting point material such as wax to the image forming layer. In addition, by adding inorganic fine particles in place of the binder, the film thickness is appropriately increased so that the image forming layer breaks sharply at the interface between the heated part and non-heated part, maintaining the sharpness and sensitivity of the dots. In addition, the transfer unevenness can be improved.

In general, a low-melting-point substance such as wax tends to ooze or crystallize on the surface of the image forming layer, which may cause problems in image quality and stability over time of the thermal transfer sheet.
In order to cope with this problem, it is preferable to use a low melting point material having a small difference in Sp value from the polymer of the image forming layer, to increase compatibility with the polymer and to separate the low melting point material from 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 eutectic and prevent crystallization. As a result, an image (R, G, B, K) having a sharp dot shape and less unevenness can be obtained.
Also, in general, when the coating layer of the thermal transfer sheet absorbs moisture, the mechanical and thermal properties of the layer change, and the humidity dependence of the recording environment occurs.
In order to reduce the temperature / humidity dependency, it is preferable that the dye / binder system of the light-to-heat conversion layer and the binder system of the image forming layer be an organic solvent system.
The image-receiving sheet on which the pixels are thermally transferred is preferably a film in which a film is formed by applying polyvinyl butyral after processing with a silane coupling agent. In order to reduce the water absorption of the membrane, there is a method of introducing a polymer hydrophobization technique into polyvinyl butyral. Examples of the polymer hydrophobization technique include reacting a hydroxyl group with a hydrophobic group as described in JP-A-8-238858, and crosslinking two or more hydroxyl groups with a hardener.

Also, normally, the image forming layer is heated to about 500 ° C or more during printing by laser exposure, and some of the pigments that have been used in the past are thermally decomposed. This can be prevented by adopting the above.
In order to prevent the hue from changing when the infrared absorbing dye moves from the photothermal conversion layer to the image forming layer due to high heat during printing, the infrared absorbing dye / It is preferable to design the photothermal conversion layer with a combination of binders.
In general, energy is insufficient in high-speed printing, and a gap corresponding to the interval of laser sub-scanning is generated. As described above, increasing the dye concentration in the photothermal conversion layer and reducing the thickness of the photothermal conversion layer / image forming layer can increase the efficiency of heat generation / transfer. Furthermore, it is preferable to add a low-melting-point substance to the image forming layer for the purpose of enhancing the effect of slightly flowing the image forming layer during heating to fill the gap and the adhesion to the film on the image receiving sheet. Further, in order to increase the adhesion between the film on the image receiving sheet and the image forming layer and to give the transferred image (R, G, B, K) sufficient strength, for example, as described above, the image is used as a film binder. The same resin as the forming layer can be used.

The image receiving sheet and the thermal transfer sheet are preferably held in a laser recording apparatus by vacuum contact. This vacuum contact is important because the image transfer behavior is very sensitive to the clearance between the image receiving surface of the image receiving sheet and the image forming layer surface of the thermal transfer sheet because an image is formed by controlling the adhesive force between the two. If the clearance between materials increases due to foreign matter such as dust, image defects and image transfer unevenness occur.
In order to prevent such image defects and image transfer unevenness, it is preferable to improve the air flow and obtain a uniform clearance by making the heat transfer sheet uniform unevenness.

  As a method for forming irregularities on the thermal transfer sheet, there are generally post-treatment such as embossing treatment and addition of a matting agent to the coating layer, but the addition of the matting agent is preferred for simplifying the production process and stabilizing the material over time. The matting agent needs to be larger than the coating layer thickness, and if the matting agent is added to the image forming layer, there will be a problem that the image of the portion where the matting agent exists is lost. It is preferable to add to the conversion layer, whereby the image forming layer itself has a substantially uniform thickness, and an image having no defect can be obtained on the image receiving sheet.

In order to reliably reproduce the sharp dots as described above, the recording apparatus to which the laser thermal transfer sheet is applied is also required to have a high-precision design. The basic configuration is the same as that of a conventional laser thermal transfer recording apparatus. This conventional configuration is a so-called heat mode recording system in which a recording head equipped with a plurality of high-power lasers irradiates a fixed thermal transfer sheet and image receiving sheet with laser irradiation. Among them, the following aspect is a preferable configuration.
The supply of the thermal transfer sheet and the image receiving sheet is a fully automatic roll supply. The image receiving sheet and the thermal transfer sheet are fixed to the recording apparatus by vacuum suction. A large number of vacuum suction holes are formed in the recording apparatus, and the sheet is adsorbed to the image receiving sheet by reducing the pressure under the image receiving sheet with a blower or a decompression pump. Since the thermal transfer sheet is adsorbed to the image receiving sheet, the size of the thermal transfer sheet is made larger than that of the image receiving sheet.

In this device, it is assumed that a large number of B2 size sheets can be stacked on the discharge table. For this purpose, a method is adopted in which air is ejected between the two sheets to lift the sheet discharged later.
A configuration example of this apparatus is shown in FIG.
The sequence by the thermal transfer sheet in this apparatus as described above will be described.
1) The sub-scanning axis of the recording head 2 of the recording apparatus 1 is returned to the original position by the sub-scanning rail 3, the main scanning rotation axis of the recording drum 4 and the thermal transfer sheet loading unit 5.
2) The image receiving sheet roll 6 is unwound by the conveying roller 7, and the front end of the image receiving sheet is vacuum sucked and fixed onto the recording drum 4 through a suction hole provided in the recording drum.
3) The squeeze roller 8 descends onto the recording drum 4 and stops when the image receiving sheet is further conveyed by the rotation of the drum while holding the image receiving sheet, and is cut by the cutter 9 to a specified length.
4) Further, the recording drum 4 makes one round 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-color thermal transfer sheet K is unwound from the thermal transfer sheet roll 10K, cut and loaded.
6) Next, when the recording drum 4 starts to rotate at high speed, the recording head 2 on the sub-scanning rail 3 starts to move and reaches the recording start position. Is done. Irradiation ends at the recording end position, and the sub-scanning rail operation and drum rotation stop. Return the recording head on the sub-scanning rail to the origin.
7) Only the thermal transfer sheet K is peeled off while leaving the image receiving sheet on the recording drum. Therefore, the tip of the thermal transfer sheet K is hooked with a nail and pulled out in the discharge direction, and discarded from the disposal port 32 to the disposal box 35.
8) Repeat steps 5) to 7) for the remaining three colors and K color. The recording order is black, followed by red, green, blue and black. That is, the second color—red—thermal transfer sheet R is from the thermal transfer sheet roll 10R, the third color—green—thermal transfer sheet G is the thermal transfer sheet roll 10G, and the fourth color—blue—thermal transfer sheet B is the thermal transfer sheet roll 10B and black. The thermal transfer sheet K is sequentially fed out from the thermal transfer sheet roll 10K.
9) When the step 8) is 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 discharged to the discharge table, a plurality of sheets can be stacked by blowing air 34 from below the discharge port 33.

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

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

  Examples of the adhesive material disposed on the surface of the adhesive roll include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyolefin resin, polybutadiene resin, styrene-butadiene copolymer (SBR), and styrene-ethylene- Butene-styrene copolymer (SEBS), acrylonitrile-butadiene copolymer (NBR), polyisoprene resin (IR), styrene-isoprene copolymer (SIS), acrylate copolymer, polyester resin, polyurethane resin, An acrylic resin, butyl rubber, polynorbornene, etc. are mentioned.

  The adhesive roll 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 the contact pressure is in contact.

  The absolute value of the difference between the surface roughness Rz on the surface of the image forming layer of the thermal transfer sheet and the surface roughness Rz on the surface of the back layer is 3.0 μm or less, and the surface roughness Rz of the image receiving sheet and the surface roughness of the surface of the back layer The absolute value of the Rz difference is preferably 3.0 μm or less. With such a configuration, it is possible to prevent image defects in combination with the above-described cleaning means, to eliminate a conveyance jam, and to further improve dot gain stability.

  In this specification, the surface roughness Rz refers to the ten-point average surface roughness corresponding to JIS Rz (maximum height), and the average surface of the portion extracted from the roughness surface by the reference area. Is used as a reference plane, and the distance between the average value of the altitude of the mountain from the highest to the fifth and the average value of the depth of the valley from the deepest to the fifth is input-converted. A stylus type three-dimensional roughness meter (Surfcom 570A-3DF) manufactured by Tokyo Seimitsu Co., Ltd. is used for the measurement. The measurement direction is the vertical direction, the cut-off 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 image forming layer surface of the thermal transfer sheet and the surface roughness Rz of the back surface thereof is 1.0 μm or less, and the surface roughness Rz of the image receiving sheet and the surface of the back surface The absolute value of the difference in the surface roughness Rz is preferably 1.0 μm or less from the viewpoint of further improving the above effect.

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

  The glossiness of the image forming layer of the thermal transfer sheet 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 film thickness of the image forming layer. Higher glossiness is more suitable for use as a uniform and high-definition image as an image forming layer. However, when smoothness is high, resistance during conveyance becomes larger, and both are in a trade-off relationship. If the gloss level is in the range of 80 to 99, it is possible to achieve a balance between the two.

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

  The Vickers hardness is a hardness obtained by applying a static load to a regular quadrangular pyramid diamond indenter having a facing angle of 136 degrees and measuring the hardness. The Vickers hardness Hv is obtained by the following equation.

Hardness Hv = 1.854 P / d ² (kg / mm ² ) ≈18.1692 MPa
Where P: Load size (Kg), d: Diagonal square length (mm)

In the present invention, the adhesive material used for the above-mentioned adhesive roll has an elastic modulus at 20 ° C. of 200 kg / cm ² (≈19.6 MPa) or less. Therefore, it is preferable that the image defects can be suppressed.
The outer drum method has been mainly described above, but an inner drum method or a flat bed method may be used. When a rigid body such as glass is used as the image receiving sheet, a flat bed method is used.

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

The laser light used for light irradiation is preferably multi-beam light, and particularly preferably a multi-beam two-dimensional array. The multi-beam two-dimensional array uses a plurality of laser beams when recording by laser irradiation, and a plurality of spot arrays of these laser beams are arranged along the main scanning direction and along the sub-scanning direction. A two-dimensional planar array consisting of rows.
By using laser light that is a multi-beam two-dimensional array, the time required for laser recording can be shortened.

  The laser beam used can be used without particular limitation as long as it is a multi-beam, gas laser beam such as argon ion laser beam, helium neon laser beam, helium cadmium laser beam, solid laser beam such as YAG laser beam, Direct laser light such as semiconductor laser light, dye laser light, and excimer laser light is used. Or the light etc. which converted these laser lights into the half wavelength through the 2nd harmonic element can also be used. In the multicolor image forming method, it is preferable to use semiconductor laser light in consideration of output power, ease of modulation, and the like. In the multicolor image forming method, the laser beam is preferably irradiated under conditions such that the beam diameter on the photothermal conversion layer is in the range of 5 to 50 μm (particularly 6 to 30 μm), and the scanning speed is 1 m / second. It is preferable to set it above (especially 3 m / sec or more).

The thickness of the image forming layer in each of the black, red, green and blue thermal transfer sheets is preferably 0.1 to 5 μm, more preferably 0.3 to 4 μm, and particularly preferably 0.5 to 3 μm.
If the thickness of the image forming layer in the thermal transfer sheet of each color is less than 0.1 μm, the density may decrease due to transfer unevenness during laser recording. On the other hand, if the thickness exceeds 5 μm, the transfer sensitivity may decrease or the resolution may deteriorate. May occur.

As a method of forming the image (R, G, B, K), the image (R, G, B, K) may be formed on the same image receiving sheet using the thermal transfer sheet as described above. The images (R, G, B, K) may be formed by forming images once on a plurality of image receiving sheets and then transferring them again to another substrate.
Further, a transparent protective layer may be further provided on the formed image (R, G, B, K).

Thermal transfer recording using laser light irradiation, if the laser beam can be converted into heat and the image forming layer containing the pigment is transferred to the image receiving sheet using the thermal energy, and an image can be formed on the image receiving sheet, The state change of the pigment, dye, or image forming layer at the time of transfer includes any state of a solid state, a softened state, a liquid state, and a gas state, and is preferably a solid or softened state. Thermal transfer recording using laser light irradiation includes, for example, conventionally known melt transfer, transfer by ablation, sublimation transfer, and the like.
Among these, the above-described thin film transfer type and melting / ablation type are preferable in that an image having a favorable hue is formed.

A PD system can be applied in the case where the image (R, G, B, K) of the color filter is formed as a printed matter by applying the plate making system using the above four types of laser thermal transfer sheets.
Specific system connection examples are given below.
When proofing a printed material from a plate making system (for example, Celebra manufactured by Fuji Photo Film Co., Ltd.), the system connection is as follows. Connect a CTP (Computer To Plate) system to the plate-making system. The printed material thus output is applied to a printing machine to obtain a final printed matter. The recording apparatus is connected as a multicolor image to the plate making system, and a PD system (registered trademark) is connected as proof drive software for bringing colors and halftone dots close to the printed material.
The contone (continuous tone) data converted into raster data by the plate making system is converted into binary data for halftone dots, outputted 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 received data according to a four-dimensional (R, B, G, K) table so that the color matches the printed matter. Finally, the data is converted into binary data for halftone dots so as to coincide with the halftone dots of the printed matter, output to a recording apparatus holding a laser thermal transfer sheet, and an image (R, G, B, K) on the image receiving sheet. A filter consisting of
The four-dimensional table is experimentally created in advance and stored in the system. The experiment for creation is as follows. Prepare an image of important color data printed via the CTP system and an image output by the recording device via the PD system, compare the colorimetric values, and create a table so that the difference is minimized.

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

(Support)
There is no particular limitation on the material of the support of the thermal transfer sheet, and various support materials can be used according to the purpose. The support preferably has rigidity, good dimensional stability, and can withstand 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 (fragrance And synthetic resin materials such as polyimide, polyamideimide, polysulfone, and polyethersulfone. Among these, biaxially stretched polyethylene terephthalate and polyethersulfone are preferable in view of mechanical strength and dimensional stability against heat. When used for producing a color proof using laser recording, the support of the thermal transfer sheet is preferably formed from a transparent synthetic resin material that transmits laser light. The thickness of the support is preferably 25 to 130 μm, and particularly preferably 50 to 120 μm. The center line average surface roughness Ra (measured based on JIS B0601 using a surface roughness measuring machine (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 in the longitudinal direction of the support is preferably 200 to 1200 kg / mm ² (≈2 to 12 GPa), and the Young's modulus in the width direction is preferably 250 to 1600 kg / mm ² (≈2.5 to 16 GPa). The F-5 value in the longitudinal direction of the support is preferably 5 to 50 kg / mm ² (≈49 to 490 MPa), and the F-5 value in the width direction of the support is preferably 3 to 30 kg / mm ² (≈29. 4 to 294 MPa), and the F-5 value in the longitudinal direction of the support is generally higher than the F-5 value in the width direction of the support, but particularly when the strength in the width direction needs to be increased. Not as long. The heat shrinkage rate 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 rate at 80 ° C. for 30 minutes is preferably 1%. Hereinafter, it is more preferably 0.5% or less. The breaking strength is preferably 5 to 100 kg / mm ² (≈49 to 980 MPa) in both directions, and the elastic modulus is preferably 100 to 2000 kg / mm ² (≈0.98 to 19.6 GPa).

In order to improve the adhesion to the photothermal conversion layer provided on the support of the thermal transfer sheet, a surface activation treatment and / or one or more undercoat layers may be provided. Examples of the surface activation treatment include glow discharge treatment and corona discharge treatment. As a material for the undercoat layer, it is preferable that both surfaces of the support and the light-to-heat conversion layer exhibit high adhesion, have low thermal conductivity, and have excellent heat resistance. Examples of such a material for the undercoat layer include styrene, styrene-butadiene copolymer, gelatin and the like. The total thickness of the undercoat layer is usually 0.01 to 2 μm. In addition, various functional layers such as an antireflection layer and an antistatic layer can be provided on the surface of the thermal transfer sheet opposite to the side on which the photothermal conversion layer is provided, or surface treatment can be performed as necessary.

(Back layer)
A back layer can be provided on the surface opposite to the photothermal conversion layer and the image forming layer of the thermal transfer sheet. Antistatic agents used in the back layer include nonionic surfactants such as polyoxyethylene alkylamines and glycerin fatty acid esters, cationic surfactants such as quaternary ammonium salts, and anionic interfaces such as alkyl phosphates. Compounds such as activators, amphoteric surfactants and conductive resins can be used.

Conductive fine particles can also be used as an antistatic agent. Examples of such conductive fine particles include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , MgO, BaO, CoO, CuO, Cu ₂ O, CaO, SrO, BaO ₂ , PbO, PbO ₂ , MnO ₃ , MoO ₃ , SiO ₂ , ZrO ₂ , Ag ₂ O, Y ₂ O ₃ , Bi ₂ O ₃ , Ti ₂ O ₃ , Sb ₂ O ₃ , Sb ₂ O ₅ , K ₂ Ti ₆ O ₁₃ , NaCaP ₂ O ₁₈ , MgB ₂ O _5, etc .; CuS, ZnS, etc. sulfides; SiC, TiC, ZrC, VC, NbC, MoC, WC, etc. carbides; Si ₃ N ₄ , TiN, ZrN, VN Nitrides such as NbN, Cr ₂ N; TiB ₂ , ZrB ₂ , NbB ₂
, Borides such as TaB ₂ , CrB, MoB, WB, LaB ₅ ; silicides such as TiSi ₂ , ZrSi ₂ , NbSi ₂ , TaSi ₂ , CrSi ₂ , MoSi ₂ , WSi ₂ ; BaCO ₃ , CaCO ₃ , SrCO ₃ , BaSO _4, CaSO ₄ and the like metal _{salts; SiN 4 -SiC, 9Al 2 O} 3 -2B 2 O 3 composite of the like, may be used alone or in combination of two or more of these kinds. Of these, SnO ₂ , ZnO, Al ₂ O ₃ , TiO ₂ , In ₂ O ₃ , MgO, BaO and MoO ₃ are preferred, SnO ₂ , ZnO, In ₂ O ₃ and TiO ₂ are more preferred, and SnO ₂ is preferred. Particularly preferred.

  In addition, it is preferable that the antistatic agent used for a back layer is substantially transparent so that a laser beam can be permeate | transmitted.

  When a conductive metal oxide is used as an antistatic agent, the particle size is preferably as small as possible to minimize light scattering, but is determined using the ratio of the refractive index of the particles and the binder as a parameter. It can be obtained using Mie's theory. In general, 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. The average particle diameter here is a value including not only the primary particle diameter of the conductive metal oxide but also the particle diameter of the higher order structure.

  In addition to the antistatic agent, various additives such as surfactants, slipping agents and matting agents, and binders can be added to the back layer.

  Examples of the binder used for forming the back layer include homopolymers and copolymers of acrylic acid monomers such as acrylic acid, methacrylic acid, acrylic ester, and methacrylic ester, nitrocellulose, methylcellulose, ethylcellulose, and cellulose. Cellulose polymer such as acetate, polyethylene, polypropylene, polystyrene, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, polyvinyl pyrrolidone, polyvinyl butyral, vinyl polymer such as polyvinyl alcohol and copolymer of vinyl compounds Condensation polymers such as polymers, polyesters, polyurethanes, polyamides, rubber-based thermoplastic polymers such as butadiene-styrene copolymers, and photopolymerizable or thermopolymerizable compounds such as epoxy compounds. , Polymers obtained by crosslinking, and melamine compounds.

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

As the binder contained in the photothermal conversion layer, a resin having at least strength capable of forming a layer on a support and having high thermal conductivity is preferable. Further, when the image is recorded, the resin having heat resistance that is not decomposed by heat generated from the light-to-heat conversion substance can smooth the surface of the light-to-heat conversion layer after light irradiation even when light irradiation with high energy is performed. Can be maintained. Specifically, a resin having a thermal decomposition temperature (temperature at which the temperature is reduced by 5% in an air stream at a rate of temperature increase of 10 ° C./min by TGA method (thermal mass spectrometry)) of 400 ° C. or more is preferable A resin having a decomposition temperature of 500 ° C. or higher is more preferable. Moreover, it is preferable that a binder has a glass transition temperature of 200-400 degreeC, and it is more preferable that it has a glass transition temperature of 250-350 degreeC. When the glass transition temperature is lower than 200 ° C., fog may occur in the formed image. When the glass transition temperature is higher than 400 ° C., the solubility of the resin may be reduced and the production efficiency may be reduced.
In addition, it is preferable that the heat resistance (for example, heat distortion temperature and thermal decomposition temperature) of the binder of the photothermal conversion layer is higher than materials used for other layers provided on the photothermal conversion layer.

  Specifically, acrylic resin such as polymethyl methacrylate, polycarbonate, polystyrene, vinyl chloride / vinyl acetate copolymer, vinyl resin such as polyvinyl alcohol, polyvinyl butyral, polyester, polyvinyl chloride, polyamide, polyimide, Examples include polyetherimide, polysulfone, polyethersulfone, aramid, polyurethane, epoxy resin, urea / melamine resin, and the like. Among these, a polyimide resin is preferable.

  In particular, the polyimide resins represented by the following general formulas (I) to (VII) are soluble in an organic solvent, and it is preferable to use these polyimide resins because the productivity of the thermal transfer sheet is improved. Moreover, it is preferable also from the point which the viscosity stability, long-term storage property, and moisture resistance of the coating liquid for photothermal conversion layers improve.

In the general formulas (I) and (II), Ar ¹ represents an aromatic group represented by the following structural formulas (1) to (3), and n represents an integer of 10 to 100.

In the general formulas (III) and (IV), Ar ² represents an aromatic group represented by the following structural formulas (4) to (7), and n represents an integer of 10 to 100.

  In said general formula (V)-(VII), n and m show the integer of 10-100. In the formula (VI), the ratio of n: m is 6: 4 to 9: 1.

  In addition, as a standard for determining whether or not the resin is soluble in an organic solvent, it is based on the fact that the resin dissolves 10 parts by mass or more with respect to 100 parts by mass of N-methylpyrrolidone at 25 ° C. In the case where it is dissolved by mass part or more, it is preferably used as a resin for the photothermal conversion layer. More preferably, it is a resin that dissolves 100 parts by mass or more with respect to 100 parts by mass of N-methylpyrrolidone.

  Examples of the matting agent contained in the photothermal conversion layer include 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, boron nitride and other metal salts, kaolin, clay, talc, zinc white, Lead white, sieglite, quartz, diatomaceous earth, barlite, bentonite, mica, synthetic mica and the like can be mentioned. Examples of the organic fine particles include resin particles such as fluororesin particles, guanamine resin particles, acrylic resin particles, styrene-acrylic copolymer resin particles, silicone resin particles, melamine resin particles, and epoxy resin particles.

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

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

The light-to-heat conversion layer is prepared by dissolving a light-to-heat conversion substance and a binder, preparing a coating solution to which a matting agent and other components are added, if necessary, and applying the solution onto a support and drying. be able to. Examples of the organic solvent for dissolving the polyimide resin include n-hexane, cyclohexane, diglyme, xylene, toluene, ethyl acetate, tetrahydrofuran, methyl ethyl ketone, acetone, cyclohexanone, 1,4-dioxane, 1,3-dioxane, dimethyl. Examples include acetate, N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, γ-butyrolactone, ethanol, methanol, and the like. Application | coating and drying can be performed using a normal application | coating and drying method. The drying is usually performed at a temperature of 300 ° C. or lower, and is preferably performed at a temperature of 200 ° C. or lower. When polyethylene terephthalate is used as the support, it is preferably dried at a temperature of 80 to 150 ° C.

If 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, causing color mixing of the image It becomes. Moreover, when there are too many polyimide resins, in order to achieve a fixed light absorption rate, the layer thickness of a photothermal conversion layer will become large, and it will be easy to cause a sensitivity fall. The solid mass ratio of the photothermal conversion substance and the binder in the photothermal conversion layer is preferably 1:20 to 2: 1, and more preferably 1:10 to 2: 1.
Further, it is preferable to make the photothermal conversion layer thin because the thermal transfer sheet can be made highly sensitive as described above. The photothermal conversion layer is preferably 0.03 to 1.0 μm, and more preferably 0.05 to 0.5 μm. In the photothermal conversion layer, the absorption wavelength of laser light is preferably in the range of 700 to 1500 nm, particularly preferably 750 to 1000 nm. Further, when the optical density is 0.7 to 1.1 with respect to light having a wavelength of 830 nm, transfer sensitivity of the image forming layer is preferably improved, and 0.8 to 0.8 with respect to light having the wavelength. More preferably, it has an optical density of 1.0. If the optical density at a wavelength of 830 nm is less than 0.7, it is insufficient to convert the irradiated light into heat, and transfer sensitivity may be lowered. On the other hand, if it exceeds 1.1, the function of the photothermal conversion layer is affected during recording, and fogging may occur.

(Image forming layer)
The image forming layer contains at least a pigment to be transferred to the image receiving sheet to form an image (R, G, B, K), and further contains a binder for forming the layer, and optionally other components. contains.
Pigments are generally classified into organic pigments and inorganic pigments. The former is particularly excellent in transparency of the coating film, and the latter is generally excellent in hiding properties. That's fine. In addition, metal powder, metal oxide powder, fluorescent pigment, and the like may be used. Examples of pigments that can be suitably used include azo pigments, phthalocyanine pigments, anthraquinone pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, and nitro pigments. The pigments used in the image forming layer are listed below according to hue, but are not limited thereto. These pigments are used alone or in combination.

1) Red pigment C.I. I. Pigment red 97, C.I. I. Pigment red 122, C.I. I. Pigment red 149, C.I. I. Pigment red 168, C.I. I. Pigment red 177, C.I. I. Pigment red 180, C.I. I. Pigment red 192, C.I. I. Pigment Red 215, CI No. 12085, CI No. 12120, CI No. 12140, CI No. 12315, etc. 2) Green Pigment C.I. I. Pigment green 7, C.I. I. Pigment Green 36, CI No. 42053, CI No. 42085, CI No. 42095 and other organic pigments 3) Blue pigments C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15: 6, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Organic pigments such as CI Pigment Blue 64, CI No. 42052, CI No. 42090

4) Yellow Pigment Pigment Yellow (Pigment Yellow) 12 (C.I.No. 21090)
Example) Permanent Yellow (permanent yellow) DHG (manufactured by Clariant Japan Co., Ltd.), Lionol Yellow (Rionol Yellow) 1212B (manufactured by Toyo Ink Co., Ltd.), Irgalite Yellow (Irgarite Yellow) LCT (Ciba Specialty Tea) Chemicals Co., Ltd.), Symbol Fast Yellow (Shimla First Yellow) GTF 219 (Dainippon Ink Chemical Co., Ltd.)
Pigment Yellow (Pigment Yellow) 13 (C.I.No. 21100)
Example) Permanent Yellow (permanent yellow) GR (manufactured by Clariant Japan), Lionol Yellow (Rionol Yellow) 1313 (manufactured by Toyo Ink Manufacturing Co., Ltd.)
Pigment Yellow (Pigment Yellow) 14 (C.I.No. 21095)
Example) Permanent Yellow (permanent yellow) G (manufactured by Clariant Japan Co., Ltd.), Lionol Yellow (Lionol Yellow) 1401-G (manufactured by Toyo Ink Co., Ltd.), Seika Fast Yellow (Seika First Yellow) 2270 (Daisensei) Chemical Industry Co., Ltd.), Symfaster Yellow (Shimla First Yellow) 4400 (Dainippon Ink Chemical Co., Ltd.)
Pigment Yellow (Pigment Yellow) 17 (C.I.No. 21105)
Example) Permanent Yellow (permanent yellow) GG02 (manufactured by Clariant Japan Co., Ltd.), Symbol Fast Yellow (Shimler First Yellow) 8GF (manufactured by Dainippon Ink & Chemicals, Inc.)
Pigment Yellow (Pigment Yellow) 155
Example) Graphtol Yellow (Graphtor Yellow) 3GP (manufactured by Clariant Japan Co., Ltd.)
Pigment Yellow (Pigment Yellow) 180 (C.I.No. 21290)
Example) Novoperperm Yellow (Novo Palm Yellow) P-HG (Clariant Japan Co., Ltd.), PV Fast Yellow (First Yellow) HG (Clariant Japan Co., Ltd.)
Pigment Yellow (Pigment Yellow) 139 (C.I.No. 56298)
Example) Novoperm Yellow (Novo Palm Yellow) M2R 70 (manufactured by Clariant Japan Co., Ltd.)

5) Magenta pigment Pigment Red 57: 1 (C.I. No. 15850: 1)
Example) Graphtol Rubine (Graphtor Rubin) L6B (manufactured by Clariant Japan Co., Ltd.), Lionol Red (Rionol Red) 6B-4290G (manufactured by Toyo Ink Co., Ltd.), Irgalite Rubine (Irgarite Rubin) 4BL (Ciba Specialty Chemicals Co., Ltd.), Symbler Brilliant Carmine 6B-229 (Dainippon Ink Chemical Co., Ltd.)
Pigment Red 122 (C.I.No. 73915)
Example) Hosterperm Pink (Hoster Palm Pink) E (manufactured by Clariant Japan Co., Ltd.), Lionogen Magenta (Rionogen Genagenta) 5790 (manufactured by Toyo Ink Co., Ltd.), Fastogen Super Magenta (Fastgen Super Magenta) RH (Large) (Made by Nippon Ink Chemical Co., Ltd.)
Pigment Red 53: 1 (C.I.No. 15585: 1)
Example) Permanent Lake Red (Permanentley Red) LCY (manufactured by Clariant Japan Co., Ltd.), Symuler Lake Red (Shimla Lake Red) C conc (manufactured by Dainippon Ink & Chemicals, Inc.)
Pigment Red 48: 1 (C.I.No. 15865: 1)
Example) Lionol Red (Rionol Red) 2B 3300 (manufactured by Toyo Ink Manufacturing Co., Ltd.), Simulator Red (Shimla Red) NRY (manufactured by Dainippon Ink & Chemicals, Inc.)
Pigment Red 48: 2 (C.I.No. 15865: 2)
Example) Permanent Red (Permanent Red) W2T (manufactured by Clariant Japan Co., Ltd.), Lionol Red (Lionol Red) LX235 (manufactured by Toyo Ink Co., Ltd.), Simulator Red (Shimla Red) 3012 (Dainippon Ink Chemical Co., Ltd.) Made by Co., Ltd.)
Pigment Red 48: 3 (C.I.No. 15865: 3)
Example) Permanent Red (Permanent Red) 3RL (manufactured by Clariant Japan Co., Ltd.), Symuler Red (Shimla Red) 2BS (manufactured by Dainippon Ink & Chemicals, Inc.)
Pigment Red (Pigment Red) 177 (C.I.No. 65300)
Example) Chromophthal Red (chromophthaled red) A2B (Ciba Specialty Chemicals Co., Ltd.)

6) Cyan Pigment Pigment Blue (Pigment Blue) 15 (C.I.No. 74160)
Example) Lionol Blue (Lionol Blue) 7027 (Toyo Ink Manufacturing Co., Ltd.), Fastogen Blue (Fastgen Blue) BB (Dainippon Ink Chemical Co., Ltd.)
Pigment Blue (Pigment Blue) 15: 1 (C.I.No. 74160)
Example) Hosterperm Blue (Hoster Palm Blue) A2R (manufactured by Clariant Japan), Fastogen Blue (Fastgen Blue) 5050 (manufactured by Dainippon Ink & Chemicals, Inc.)
Pigment Blue (Pigment Blue) 15: 2 (C.I.No. 74160)
Example) Hosterperm Blue (Hoster Palm Blue) AFL (Clariant Japan Co., Ltd.), Irgalite Blue (Irgarite Blue) BSP (Ciba Specialty Chemicals Co., Ltd.), Fastogen Blue (Fastgen Blue) GP (Large) (Made by Nippon Ink Chemical Co., Ltd.)
Pigment Blue (Pigment Blue) 15: 3 (C.I.No. 74160)
Example) Hosterperm Blue (Hoster Palm Blue) B2G (manufactured by Clariant Japan Co., Ltd.), Lionol Blue (Lionol Blue) FG7330 (
Toyo Ink Mfg. Co., Ltd.), Chromophthal Blue (Chromophthal Blue) 4GNP (Ciba Specialty Chemicals Co., Ltd.), Fastogen Blue (Fastgen Blue) FGF (Dainippon Ink Chemical Co., Ltd.)
Pigment Blue (Pigment Blue) 15: 4 (C.I.No. 74160)
Example) Hosterperm Blue (Hoster Palm Blue) BFL (manufactured by Clariant Japan), Cyanine Blue (cyanine blue) 700-10FG (manufactured by Toyo Ink Co., Ltd.), Irgalite Blue (Irgarite Blue) GLNF (Ciba Special) Tea Chemicals Co., Ltd.), Fastogen Blue (Fastgen Blue) FGS (Dainippon Ink Chemical Co., Ltd.)
Pigment Blue (Pigment Blue) 15: 6 (C.I.No. 74160)
Example) Lionol Blue (Lionol Blue) ES (Toyo Ink Manufacturing Co., Ltd.)
Pigment Blue (Pigment Blue) 60 (C.I.No. 69800)
Example) Hosterperm Blue (Hoster Palm Blue) RL01 (manufactured by Clariant Japan), Lionogen Blue (Rionogen Blue) 6501 (manufactured by Toyo Ink Manufacturing Co., Ltd.)

7) Black pigment 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 (manufactured by Cabot Co. (Cabot Corporation))

In addition, examples of pigments that can be used in the present invention include “Handbook of Pigments, edited by Japan Pigment Technical Association, Seibundo Shinkosha, 1989”, “COLOUR INDEX, THE SOCIETY OF DYES &
Products can be selected as appropriate by referring to "COLOURIST, THIRD EDITION, 1987".

As an average particle diameter of the said pigment, 0.03-1 micrometer is preferable and 0.05-0.5 micrometer is more preferable.
When the particle size is less than 0.03 μm, the dispersion cost may increase, or the dispersion may cause gelation or the like. In some cases, the adhesiveness of the image forming layer may be inhibited, and the transparency of the image forming layer may be inhibited.

Examples of the binder for the image forming layer include butyral resin, polyamide resin, polyethyleneimine resin, sulfonamide resin, polyester polyol resin, petroleum resin, styrene, vinyltoluene, α-methylstyrene, 2-methylstyrene, chlorostyrene, vinyl. Styrene and its derivatives such as benzoic acid, sodium vinylbenzene sulfonate, aminostyrene, homopolymers and copolymers of substituted products, methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, and methacrylic acid Acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, α-ethylhexyl acrylate, and dienes such as acrylic acid, butadiene, isoprene, acrylo Use of nitriles, vinyl ethers, maleic acid and maleic esters, maleic anhydride, cinnamic acid, vinyl chloride, vinyl acetate, or other vinyl monomers alone or with other monomers Can do. These resins can be used in combination of two or more.
The image forming layer may contain a reactive compound that polymerizes or crosslinks by receiving heat and / or light energy, for example, a monomer, an oligomer and / or a polymer, and if necessary, a simple substance or a composition containing a polymerization initiator. preferable. By containing these, the heat resistance and chemical resistance of the image forming layer can be improved.
Further, the light and / or heat-reactive simple substance or composition may be used in combination with (1) a binder that is not light and / or heat-reactive as described above to form an image forming layer. 2) It may be provided alone on the photothermal conversion layer as an image forming layer, or (3) may be provided in a layer form between the photothermal conversion layer and an image forming layer that is not light and / or heat reactive, 4) It may be provided on an image forming layer that is not light and / or heat responsive. In the case of (4), the image forming layer that is not light and / or heat responsive may be configured to dissolve.
The light and / or heat-reactive simple substance or composition may be provided in a layer form on a color filter formed by laser thermal transfer.

The components used in the light and / or heat-reactive simple substance or composition are listed below.
The photopolymerizable monomer is preferably a compound having a boiling point of 100 ° C. or higher at normal pressure. For example, polyethylene glycol di (meth) acrylate (meaning polyethylene glycol diacrylate and polyethylene glycol dimethacrylate; the same shall apply hereinafter), polypropylene Glycol di (meth) acrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, trimethylolpropane diacrylate, neopentylglycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, Dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, hexanediol di (meth) acrylate Polyfunctional alcohols such as rate, trimethylolpropane tri (acryloyloxypropyl) ether, tri (acryloyloxyethyl) isocyanurate, tri (acryloyloxyethyl) cyanurate, glycerol tri (meth) acrylate, trimethylolpropane or glycerol (Meth) acrylates after addition reaction of propylene oxide, and further urethane acrylates disclosed in JP-B-48-41708, JP-A-50-6034, and JP-A-51-37193 Polyester acrylates disclosed in JP-A-48-64183, JP-B-49-43191 and JP-A-52-30490, epoxy acrylate which is a reaction product of epoxy resin and (meth) acrylic acid It can be mentioned polyfunctional acrylates and methacrylates such as relations such.

  Among these, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and dipentaerythritol penta (meth) acrylate are preferable.

As the epoxy compound, glycidyl ethers of alcohols having 2 to 20 carbon atoms such as butyl glycidyl ether, octyl glycidyl ether, decyl glycidyl ether, aryl glycidyl ether, phenyl glycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, Ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether dibromoneopentyl glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, diglycerol tetra Glycidyl ether, polyglycerol polyg Polyglycidyl ethers of polyols such as sidyl ether, 2,6-diglycidylphenyl glycidyl ether, 2,6,2 ′, 6′-tetramethyl-4,4′-biphenyl glycidyl ether, bisphenol A type epoxy resin, hydrogen Additive bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated type bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated type bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, Glycidyl ether type epoxy compounds such as halogenated phenol novolac type epoxy resins and brominated epoxy resins, alicyclic diepoxy acetals, alicyclic diepoxy adipates and vinyl silanes Cyclic aliphatic epoxy compounds such as lohexenedioxide, glycidyl (meth) acrylate, tetrahydroxyphthalic acid diglycidyl ester, sorbic acid glycidyl ester, oleic acid glycidyl ester, and linolenic acid glycidyl ester, Alkylcarboxylic acid glycidyl esters such as butyl glycidyl ester, octyl glycidyl ester hexahydrophthalic acid diglycidyl ester and benzoic acid glycidyl ester, o-phthalic acid diglycidyl ester, diglycidyl p-oxybenzoic acid and dimer acid glycidyl ester Glycidyl ester type epoxy compounds such as aliphatic carboxylic acid glycidyl esters, tetraglycidyl diaminodiphenylmethane, triglycidyl-p-amino Glycidylamine type epoxy compounds such as nophenol, triglycidyl-m-aminophenol, diglycidylaniline, diglycidyltoluidine, tetraglycidyl-m-xylylenediamine, diglycidyltribromaniline and tetraglycidylbisaminomethylcyclohexane, diglycidyl And heterocyclic epoxy compounds such as hydantoin, glycidylglycidoxyalkylhydantoin, and triglycidyl isocyanurate. Particularly preferred are phenol novolac epoxy resins and cresol novolac epoxy resins.
Particularly preferred epoxy compounds are bisphenol A type epoxy resins and bisphenol F type epoxy resins, and commercially available products include Etototo YD128 and YD8125 manufactured by Tohto Kasei, and Epicron 840S, 850S, 1050, and 830 manufactured by Dainippon Ink and Chemicals.

  In order to thermally react the epoxy group of the epoxy compound, an epoxy thermosetting accelerator which is a thermosetting catalyst can be used. This epoxy thermosetting accelerator includes polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine (dipropyltriamine), bis (hexamethylene) triamine, and 1,3,6-trisaminomethylhexane. , Polymethylenediamines such as trimethylhexamethylenediamine, polyetherdiamine and diethylaminopropylamine, fats such as mensendiamine, isophoronediamine, bis (4-amino-3-methylcyclohexyl) methane and N-aminoethylpiperazine Primary aromatic amines such as cyclic polyamines, aromatic primary amines such as metaphenylenediamine, diaminophenylmethane, diaminophenylsulfone and aromatic diamine eutectic mixtures, polyamines Epoxy resin adducts, polyamine-ethylene oxide adducts, polyamine-propylene oxide adducts, modified amines such as cyanoethylated polyamines and ketoimine, secondary amines such as piperidine, piperazine, morpholine and tetramethylguanidine, triethanolamine, benzyldimethylamine, 2 , 4,6-Tris (dimethylaminomethyl) phenol and other amine compounds such as tertiary amines, phthalic anhydride, trimellitic anhydride, ethylene glycol bis (anhydrotrimellitate), glycerin tris (anhydro) Trimellitate), pyromellitic anhydride and 3,3 ′, 4,4′-benzophenone tetracarboxylic anhydride and other aromatic acid anhydrides, maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride , Methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, alkenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride and methylcyclohexene tetracarboxylic Cyclic aliphatic acid anhydrides such as acid anhydrides, aliphatic acid anhydrides such as polyadipic acid anhydrides, polyazeline acid anhydrides and polysebacic acid anhydrides, and halogenated acid anhydrides such as chlorendic acid anhydride and tetrabromophthalic anhydride Acid anhydrides such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1- Cyanoethyl-2-me Ruimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate 2-methylimidazolium isocyanurate, 2-phenylimidazolium isocyanurate, 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl-s-triazine, 2,4-diamino- 6- [2-ethyl-4-methylimidazolyl- (1)]-ethyl-s-triazine, 2,4-diamino-6- [2-undecylimidazolyl- (1)]-ethyl-s-triazine, 2 -Phenyl-4-methyl-5-hydroxymethylimidazole, 2-pheny -4,5-dihydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-di (cyanoethoxymethyl) imidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride and 1,3-dibenzyl Imidazole compounds such as 2-methylimidazolium chloride, dicyandiamide, o-tolylbiguanide, phenylbiguanide, and dicyandiamide derivatives such as α-2,5-dimethylbiguanide, carboxylic acids, phenols, quaternary ammonium salts, Known epoxy curing accelerators such as melamine derivatives, organic acid hydrazides, or methylol group-containing compounds may be mentioned. Particularly preferred are dicyandiamide and 1-benzyl-2-methylimidazole. These epoxy thermosetting accelerators may be used alone or in combination of two or more.

If desired, a crosslinking agent or a catalyst thereof can be further added to the light and / or heat-reactive composition.
Examples of the crosslinking agent include low molecular weight compounds such as polycarboxylic acids or acid anhydrides thereof (for example, itaconic acid, methylmaleic acid anhydride, dodecanedioic acid, 2-dodecenedioic acid, dodecenyl succinic acid anhydride, phthalic acid anhydride). , Tetrahydrophthalic anhydride, trimellitic anhydride, 1,2-, 1,3- and 1,4-cyclohexanedicarboxylic acid, hexahydrophthalic anhydride or mixtures thereof), polycarboxylic acid semiesters ( Polyols such as 1,6-hexanediol, trimethylolpropane and acid anhydrides such as hexahydrophthalic acid anhydride and methylhexahydrophthalic acid anhydride), aromatic polyamines, aliphatic polyamines, triazine compounds, poly Mercaptan, bisphenol A, tetrabromobisphenol , Trimethylol allyloxyphenol, polyisocyanate compounds, and the like, and the polymer compound may be phenols such as phenol novolac resin and butylated phenol resin, carboxyl group-containing unsaturated or saturated polyester, etherified Examples include urea- and / or triazine-formaldehyde resins.

  Examples of the thermosetting catalyst include tetraethylammonium bromide, tetrabutylphosphonium bromide, triphenylbenzylphosphonium chloride, triethylamine, tributylamine, bismuth nitrate, lead 2-ethylhexanoate, sodium trichlorophenolate, lithium acetate, tributyltin chloride, tributyltin. Examples include cyanate, titanium tetrachloride, dibutyl titanium dichloride, iron trichloride, ferrocene, tolphenylantimony, copper acetate, pyridine borane, calcium acetate, and barium acetate.

Examples of the reactive polymer used in the light and / or heat reactive simple substance or composition include a polymer having an unsaturated bond group, a carboxyl group, an amino group, an epoxy group, a mercapto group, a hydroxyl group, an isocyanate group, and the like. It is done.
For example, the copolymer which consists of a monomer first represented by the monomer represented by general formula (a), the monomer represented by general formula (b), and general formula (c) is mentioned.

In the above monomer, R ₁ , R ₂ , R ₃ and R ₅ each represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms.
R ₄ represents an alkyl group having 1 to 5 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms.
R ₆ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms or a halogen atom, and a hydrogen atom, an alkyl group having 1 to 2 carbon atoms, an alkoxyl group having 1 to 2 carbon atoms or A chlorine atom and a bromine atom are preferable. n shows the integer of 1-10, and 1-8 are preferable.

  The copolymer of the monomer (a), monomer (b) and monomer (c) is not particularly limited and may be random or regular, for example, block or graft.

  As the reactive polymer, secondly, (A) a repeating unit derived from at least one compound selected from the group consisting of acrylic acid and methacrylic acid, and (B) a group consisting of benzyl acrylate and benzyl methacrylate. Derived from at least one compound selected from the group consisting of repeating units derived from at least one selected compound and optionally (C) an alkyl methacrylate containing an alkyl group having 1 to 12 carbon atoms. A copolymer containing a repeating unit and having a mass average molecular weight of preferably 5,000 to 50,000, more preferably 10,000 to 42,000.

Specific examples of the component (C) include methyl (meth) acrylate (meaning methyl acrylate and methyl methacrylate; hereinafter the same), ethyl (meth) acrylate, propyl (meth) acrylate, and 1-propyl (meth) acrylate. , Butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, 2-methylbutyl (meth) acrylate, 3-methylbutyl (meth) acrylate , Hexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, noni (Meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, the monomer (a), it is possible to include a monomer (b) and monomer (c) or the like. Of these, methyl methacrylate and the like are preferable.

Among the second reactive polymers, preferred specific examples include benzyl methacrylate / methacrylic acid copolymer (molar ratio of repeating units = 73: 27, mass average molecular weight = 40,000), benzyl methacrylate / benzyl acrylate / Methacrylic acid terpolymer (molar ratio of repeating units = 60: 13: 27, mass average molecular weight = 32,000), benzyl methacrylate / acrylic acid / methacrylic acid terpolymer (molar ratio of repeating units = 73) : 8: 19, mass average molecular weight = 35,000), benzyl methacrylate / methyl methacrylate / methacrylic acid terpolymer (molar ratio of repeating units = 60: 13: 27, mass average molecular weight = 46,000). I can list them.

  Examples of the photopolymerization initiator used in the present invention include α-diketones such as benzyl and diacetyl, acyloins such as benzoin, acyloin ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether, thioxanthone, 2 , 4-diethylthioxanthone, thioxanthone-1-sulfonic acid, thioxanthone such as thioxanthone-4-sulfonic acid, benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, etc. Benzophenones, acetophenone, p-dimethylaminoacetophenone, α, α′-dimethoxyacetoxyacetophenone, 2,2′-dimethoxy-2-phenylacetophenone, p-methoxyacetophenone, 2-methyl- [ Acetophenones such as 4- (methylthio) phenyl] -2-morpholino-1-propanone and quinones such as anthraquinone and 1,4-naphthoquinone, phenane silk chloride, tribromomethylphenylsulfone, tris (trichloromethyl) -s- Triazines, 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) triazines, halogen compounds such as compounds described in JP-A-63-153542, peroxides such as di-t-butyl peroxide Etc. Particularly preferred are 2,2′-dimethoxy-2-phenylacetophenone and 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone (trade name: Irgacure 907 manufactured by Ciba-Geigy). It is done. Particularly preferred examples include 2-trichloromethyl-4′-butoxystyryl-1,3,4-oxadiazole, 2,4-bis (trichloromethyl), 6- (4′-methoxyphenyl) -s-triazine, Mention may be made of 2,4-bis (trichloromethyl) -6- {4 '-(N, N-diethoxycarbonylmethylamino) -3'-bromo} phenyl-s-triazine.

  These photopolymerization initiators may be used alone or in combination of two or more. Examples of such a mixture of two or more types include a combination of 2,4,5-triarylimidazole dimer and 2-mercaptobenzoxazole or leucocrystal violet, etc., and 4,4 described in US Pat. No. 3,427,161. A combination of '-bis (dimethylamino) benzophenone and benzophenone or benzoin methyl ether, benzoyl-N-methylnaphthothiazoline and 2,4-bis (trichloromethyl) -6- (4-methoxy) described in US Pat. No. 4,239,850 A combination of dimethylthioxanthone and 4-dialkylaminobenzoate described in JP-A-57-23602, and 4,4′-bis (dialkylamino) described in JP-A-59-78339. ) Benzophenone, ketones and tri Combination of a halogenated methyl-containing compounds.

  It is preferable that the photopolymerization initiator has substantially no sensitivity to light having a wavelength of 400 nm or longer. Having substantially no sensitivity is determined by the spectral sensitivity spectrum of the photopolymerization initiator and the spectral characteristics of the thermal transfer sheet. The area (A) of the spectral sensitivity spectrum of the photopolymerization initiator of 400 nm or more and the thermal transfer sheet Is defined by a ratio (A / B) of an area (B) of 400 nm or less from the lowest wavelength at which the transmittance of 10% or more is obtained, and means that the value of A / B is 0.1 or less.

If necessary, the light and / or heat-reactive composition may be a colorant such as a pigment, a thermal polymerization inhibitor, an adhesion promoter, a dispersant, a plasticizer, an anti-sagging agent, a leveling agent, an antifoaming agent, You may mix | blend auxiliary additives, such as a flame retardant and a brightener.
Examples of thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, pt-butylcatechol, 2,6-di-t-butyl-p-cresol, β-naphthol, pyrogallol and other aromatic hydroxy compounds, benzoquinone Quinones such as p-toluquinone, amines such as naphthylamine, pyridine, p-toluidine and phenothiazine, aluminum salts or ammonium salts of N-nitrosophenylhydroxylamine, chloranil, nitrobenzene and the like.
Examples of the adhesion promoter include alkylphenol / formaldehyde novolac resin, polo vinyl ethyl ether, polyvinyl isobutyl ether, polyvinyl butyral, polyisobutylene, styrene-butadiene copolymer rubber, butyl rubber, vinyl chloride-vinyl acetate copolymer, chlorinated rubber, Acrylic resin adhesives, aromatic, aliphatic or alicyclic petroleum resins, silane coupling agents and the like can be mentioned.

The thermal transfer sheet used in the present invention is a light and / or heat reactive simple substance or composition so as to satisfy the adhesion, heat resistance, chemical resistance, etc. between the image (R, G, B, K) and the image receiving sheet. The blending ratio of the components in the product should be adjusted.
The following is illustrated as a standard of the mixture ratio of the component in this composition.
The photopolymerization initiator is preferably 0.1 to 30 parts by weight, particularly preferably 0.15 to 15 parts by weight, based on the reactive monomer. If the amount is less than 0.1 parts by mass, the sensitivity decreases. If the amount exceeds 30 parts by mass, crystal precipitation, film quality deterioration, and the like may occur.
Generally a crosslinking agent is the range of 0.2-10 mass parts with respect to 100 mass parts of the said compositions.
The usage-amount of a thermosetting catalyst is the range of 0.02-5 mass parts normally with respect to 100 mass parts of the said compositions.
The epoxy compound can be generally used in an amount of 1 to 40 parts by mass, preferably 5 to 30 parts by mass with respect to 100 parts by mass of the composition.
The reactive polymer is usually used in an amount of 10 to 95 parts by mass, preferably 20 to 90 parts by mass with respect to 100 parts by mass of the composition.
The blending ratio should be appropriately selected as appropriate in accordance with the modes (1) to (5) described later.

The light and / or heat-reactive simple substance or composition may be (1) mixed with a binder that is not light and / or heat-reactive to form an image-forming layer, or (2) alone on the light-heat conversion layer. It may be provided as a forming layer, or (3) provided in a layer form between the photothermal conversion layer and an image forming layer that is not light and / or heat-reactive, and transferred onto the image receiving sheet together with the image forming layer by laser thermal transfer. It may be configured, (4) may be provided on an image forming layer that is not light and / or heat responsive, or (5) may be provided on an image (R, G, B, K). .
In order to form layers such as the image forming layers (1) to (5) above, each composition is used as a coating solution.
Examples of organic solvents used in the coating solution include ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, alkoxyethanols such as methoxyethanol, ethoxyethanol, and butoxyethanol, carbitol, butyl carbitol, etc. Carbitols, ethyl acetate, butyl acetate, ethoxyethanol acetate, butoxyethanol acetate, carbitol acetate, acetate esters such as butyl carbitol acetate, methyl lactate, and ethyl lactate. These organic solvents may be used alone or in combination of two or more.

The light and / or heat-reactive coating layer is usually dried under conditions of 60 to 150 ° C. and 0.5 to 10 minutes. The image (R, G, B, K) transferred from the thermal transfer sheet to the image receiving sheet is subjected to a light irradiation process and / or a heating process.
As this light irradiation treatment, ultraviolet irradiation of 0.1 to 500 mJ / cm ² is usually mentioned, and an ultrahigh pressure mercury lamp or the like is preferable as the light source. Moreover, 150-250 degreeC and 10 to 120 minutes are preferable for heat processing. Note that at least one of the light irradiation treatment and the heat treatment is performed, but it is preferable to perform both, and may be performed simultaneously, or the heat treatment may be performed before or after the light irradiation treatment. .

  The image forming layer preferably contains 30 to 70% by mass of a color pigment, and more preferably 30 to 50% by mass. Further, the image forming layer preferably contains 70 to 30% by mass of resin, and more preferably 70 to 40% by mass.

The image forming layer may contain the following components (1) to (3) as the other components.
(1) Waxes Examples of 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 oxide wax, montan wax, ozokerite and ceresin. Of these, 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 wax include plant waxes such as carnauba wax, tree wax, aulicule wax, and espar wax, and animal waxes such as dense wax, insect wax, shellac wax, and whale wax.

The synthetic wax is generally used as a lubricant and is usually composed of a higher fatty acid compound. Examples of such synthetic waxes include the following.
1) Fatty acid-based wax Linear saturated fatty acid represented by the following general formula:
CH ₃ (CH ₂ ) _n COOH
In said formula, n shows the integer of 6-28. Specific examples include stearic acid, behenic acid, palmitic acid, 12-hydroxystearic acid, azelaic acid and the like.
Moreover, metal salts (for example, K, Ca, Zn, Mg etc.), such as the said fatty acid, are mentioned.
2) Fatty acid ester waxes Specific examples of the fatty acid ester include ethyl stearate, lauryl stearate, ethyl behenate, hexyl behenate, behenyl myristate, and the like.
3) Fatty acid amide wax Specific examples of the fatty acid amide include stearic acid amide and lauric acid amide.
4) Fatty alcohol-based wax Linear saturated aliphatic alcohol represented by the following general formula:
CH ₃ (CH ₂ ) _n OH
In said formula, n represents the integer of 6-28. Specific examples include stearyl alcohol.

  Among the synthetic waxes 1) to 4), higher fatty acid amides such as stearic acid amide and lauric acid amide are particularly suitable. The wax compounds can be used alone or in appropriate combination as desired.

(2) Plasticizer The plasticizer is preferably an ester compound, dibutyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, dilauryl phthalate, butyl lauryl phthalate, Phthalic acid esters such as butylbenzyl phthalate, aliphatic dibasic acid esters such as di (2-ethylhexyl) adipate, di (2-ethylhexyl) sebacate, tricresyl phosphate, tri (2-ethylhexyl) phosphate, etc. Well-known plasticizers such as polyol polyesters such as phosphoric acid triesters, polyethylene glycol esters, and epoxy compounds such as epoxy fatty acid esters. Among these, esters of vinyl monomers, particularly esters of acrylic acid or methacrylic acid are preferred in that they have a large effect of improving transfer sensitivity, improving transfer unevenness, and controlling the elongation at break.

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

In addition, the plasticizer may be a polymer, and among them, polyester is preferable in that it has a large addition effect and is difficult to diffuse under storage conditions. Examples of the polyester include sebacic acid-based polyester and adipic acid-based polyester.
The additive to be contained in the image forming layer is not limited to these. Moreover, a plasticizer may be used individually by 1 type and may use 2 or more types together.

  If the content of the additive in the image forming layer is too large, the resolution of the transferred image decreases, the film strength of the image forming layer itself decreases, or the adhesion between the photothermal conversion layer and the image forming layer decreases. In some cases, transfer of the unexposed portion to the image receiving sheet may occur. From the above viewpoint, the content of the wax is preferably 0.1 to 30% by mass, more preferably 1 to 20% by mass, based on the total solid content in the image forming layer. Moreover, as content of the said plasticizer, 0.1-20 mass% of the total solid of an image forming layer is preferable, and 0.1-10 mass% is more preferable.

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

  For the image forming layer, a coating solution in which a pigment and the binder or the like are dissolved or dispersed is prepared, and this is applied to the photothermal conversion layer (if the following thermal release layer is provided on the photothermal conversion layer) It can be provided by applying to and drying. Examples of the solvent used for preparing the coating solution include n-propyl alcohol, methyl ethyl ketone, propylene glycol monomethyl ether (MFG), methanol, water and the like. Application | coating and drying can be performed using a normal application | coating and drying method.

(Cushion layer)
It is preferable to provide a cushion layer having a cushion function between the support and the photothermal conversion layer. When a cushion layer is provided, the adhesion between the image forming layer and the image receiving layer can be improved during laser thermal transfer, and the image quality can be improved. In addition, even when foreign matter is mixed between the thermal transfer sheet and the image receiving sheet during recording, the gap between the image receiving layer and the image forming layer is reduced due to the deformation action of the cushion layer, and as a result, the size of image defects such as white spots is reduced. You can also

The cushion layer is configured to be easily deformed when stress is applied to the interface, and in order to achieve the effect, a material having a low elastic modulus, a material having rubber elasticity, or a thermoplastic resin that is easily softened by heating. Preferably it consists of. The elastic modulus of the cushion layer is preferably 0.5 MPa to 1.0 GPa, particularly preferably 1 MPa to 0.5 GPa, more preferably 10 to 100 MPa at room temperature. In order to entrap foreign substances such as dust, it is preferable that the penetration (25 ° C., 100 g, 5 seconds) defined by JIS K2530 is 10 or more. Further, the glass transition temperature of the cushion layer is 80 ° C. or lower, preferably 25 ° C. or lower, and the softening point is preferably 50 to 200 ° C. In order to adjust these physical properties, for example, Tg, a plasticizer can be suitably added to the binder.

Specific materials used as a binder for the cushion layer include rubbers such as urethane rubber, butadiene rubber, nitrile rubber, acrylic rubber, natural rubber, polyethylene, polypropylene, polyester, styrene-butadiene copolymer, ethylene -Vinyl acetate copolymer, ethylene-acrylic copolymer, vinyl chloride-vinyl acetate copolymer, vinylidene chloride resin, vinyl chloride resin with plasticizer, polyamide resin, phenol resin and the like.
In addition, although the thickness of a cushion layer changes with resin and other conditions to be used, it is 3-100 micrometers normally, Preferably it is 10-52 micrometers.

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

Examples of polymers that generate gas when decomposed or denatured by heat include auto-oxidizing polymers such as nitrocellulose, halogens such as chlorinated polyolefin, chlorinated rubber, polychlorinated rubber, polyvinyl chloride, and polyvinylidene chloride. Containing polymers, acrylic polymers such as polyisobutyl methacrylate on which volatile compounds such as moisture are adsorbed, cellulose esters such as ethyl cellulose on which volatile compounds such as moisture are adsorbed, and volatile compounds such as moisture are adsorbed And natural polymer compounds such as gelatin. Examples of the low molecular weight compound that decomposes or denatures by heat to generate gas include a diazo compound and a compound that generates gas by exothermic decomposition such as azidation.
In addition, it is preferable that decomposition | disassembly, a quality change, etc. of the heat sensitive material by the above generate | occur | produce at 280 degrees C or less, It is preferable to generate | occur | produce especially at 230 degrees C or less.

  When a low molecular weight compound is used as the heat sensitive material of the heat sensitive release layer, it is desirable to combine it with a binder. As the binder, there can be used a polymer which itself decomposes or denatures by heat to generate a gas, but a normal binder having no such property can also be used. When the thermosensitive low molecular weight compound and the binder are used in combination, the mass ratio of the former to the latter is preferably 0.02: 1 to 3: 1 and is preferably 0.05: 1 to 2: 1. Is more preferable. The heat-sensitive peeling layer preferably covers the entire surface of the light-to-heat conversion layer, and its thickness is generally from 0.03 to 1 μm, preferably from 0.05 to 0.5 μm.

In the case of a thermal transfer sheet having a structure in which a photothermal conversion layer, a thermal release layer, and an image forming layer are laminated in this order on a support, the thermal release layer is decomposed and altered by heat transmitted from the photothermal conversion layer, Generate gas. Due to this decomposition or gas generation, a part of the heat-sensitive peeling layer disappears or cohesive failure occurs in the heat-sensitive peeling layer, and the bonding force between the photothermal conversion layer and the image forming layer decreases. For this reason, depending on the behavior of the heat-sensitive peeling layer, a part of the heat-sensitive peeling layer adheres to the image forming layer and appears on the surface of the finally formed image, which may cause color mixing of the image. Therefore, even if such transfer of the heat-sensitive release layer occurs, the heat-sensitive release layer is hardly colored so that no visible color mixture appears in the formed image, that is, high in visible light. It is desirable to show permeability. Specifically, the light absorption rate of the heat-sensitive release layer is 50% or less, preferably 10% or less with respect to visible light.
In addition, instead of providing an independent thermal release layer on the thermal transfer sheet, the thermal material is added to the photothermal conversion layer coating solution to form a photothermal conversion layer, which serves as both the photothermal conversion layer and the thermal release layer. It can also be set as a simple structure.
It is preferable that the coefficient of static friction of the outermost layer on the side where the image forming layer of the thermal transfer sheet is coated is 0.35 or less, preferably 0.20 or less. By setting the static friction coefficient 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 static friction coefficient follows the method described in paragraph (0011) of Japanese Patent Application No. 2000-85759.
The smoothing value on the surface of the image forming layer is preferably 0.5 to 50 mmHg (≈0.0665 to 6.65 kPa) at 23 ° C. and 55% RH, and Ra is preferably 0.05 to 0.4 μm. In addition, a large number of microscopic voids where the image receiving layer and the image forming layer cannot come into contact can be reduced, which is preferable in terms of transfer and image quality. The Ra value can be measured based on JIS B0601 using a surface roughness measuring machine (Surfcom, manufactured by Tokyo Seiki Co., Ltd.) or the like. The surface hardness of the image forming layer is preferably 10 g or more with a sapphire needle. After charging the thermal transfer sheet according to US federal government test standard 4046, it is preferable that the charged potential of the image forming layer is -100 to 100 V 1 second after grounding the thermal transfer sheet. 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 used in combination with the thermal transfer sheet will be described.
[Image receiving sheet]
(Layer structure)
The image receiving sheet has a function of supporting an image from the thermal transfer sheet, and is composed of at least a support, and preferably has one or more image receiving layers on the support, and optionally the support and the image receiving layer. 1 layer or two layers or more of an adhesive layer, a cushion layer, a release layer, and an intermediate layer. In addition, it is preferable in terms of transportability to have a back layer on the surface of the support opposite to the image receiving layer.
The support is generally made of glass, and examples thereof include a heat-resistant flexible resin such as polyethersulfone. An image receiving layer is preferably provided on the support, and a configuration in which an adhesive layer is provided between the support and the image receiving layer is also preferable. Examples of the adhesive layer include a treatment layer using a silane coupling agent. The thickness of the adhesive layer is preferably 50 to 5 μm, more preferably 50 to 1000 mm. As silane coupling agents, for example, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and the like are known. It is commercially available from Shin-Etsu Chemical Co., Ltd. as a “silane coupling agent”. As a method for providing the silane coupling agent on the support, a method in which the silane coupling agent is applied as it is on the support in the form of a stock solution or as a coating solution by a method such as a spinner, a roll coater, a bar coater, or a curtain coater and then dried is used.

(Image receiving layer)
The image receiving layer is preferably a layer formed mainly of an organic polymer binder. The binder is preferably a thermoplastic resin, and examples thereof include homopolymers and copolymers of acrylic monomers such as acrylic acid, methacrylic acid, acrylic ester, and methacrylic ester, methyl cellulose, ethyl cellulose, Cellulose polymers such as cellulose acetate, homopolymers of vinyl monomers such as polystyrene, polyvinyl pyrrolidone, polyvinyl butyral, polyvinyl alcohol, polyvinyl chloride, and copolymers thereof, and condensation polymers such as polyester and polyamide And rubber-based 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 an appropriate adhesive force with the image forming layer. For this purpose, it is also possible to add a plasticizer to the image receiving layer. The binder polymer preferably has a Tg of 30 ° C. or higher in order to prevent blocking between sheets. As the binder polymer of the image receiving layer, it is possible to use the same or similar polymer as the binder polymer of the image forming layer in terms of improving the adhesion with the image forming layer at the time of laser recording and improving sensitivity and image strength. Particularly preferred.
It is also preferable to form at least one of the image receiving layers from a photocurable material. Examples of such a photocurable material include the same light and / or heat-reactive simple substance or composition of the image forming layer. For example, a) a photopolymerizable monomer comprising at least one of a polyfunctional vinyl or vinylidene compound capable of forming a photopolymer by addition polymerization, b) an organic polymer, c) a photopolymerization initiator, and thermal polymerization prohibited if necessary The combination which consists of additives, such as an agent, can be mentioned. As the polyfunctional vinyl monomer, an unsaturated ester of polyol, particularly an ester of acrylic acid or methacrylic acid (for example, ethylene glycol diacrylate, pentaerythritol tetraacrylate) is used.

  Examples of the organic polymer include the polymer for forming an image receiving layer. Moreover, as a photoinitiator, normal photoradical polymerization initiators, such as a benzophenone and Michler's ketone, are used in the ratio of 0.1-20 mass% in a layer.

  Once an image (R, G, B, K) is formed on the image receiving layer, it can be re-transferred to another support such as glass.

The thickness of the image receiving layer is preferably from 0.01 to 10 μm, more preferably from 0.01 to 1 μm.
The smoothing value on the surface of the image receiving layer is preferably 0.5 to 50 mmHg (≈0.0665 to 6.65 kPa) at 23 ° C. and 55% RH, and Ra is preferably 0.05 to 0.4 μm. A large number of microscopic voids where the image receiving layer and the image forming layer cannot come into contact can be reduced, which is preferable in terms of transfer and image quality. The Ra value can be measured based on JIS B0601 using a surface roughness measuring machine (Surfcom, manufactured by Tokyo Seiki Co., Ltd.) or the like. After charging the image receiving sheet according to the US federal government test standard 4046, it is preferable that the charged potential of the image receiving layer is -100 to 100 V after 1 second after grounding the image receiving sheet. The surface resistance of the image receiving layer is preferably 10 ⁹ Ω or less at 23 ° C. and 55% RH. The coefficient of static friction on the surface of the image receiving layer is preferably 0.2 or less. The surface energy of the image receiving layer surface is preferably 23 to 35 mg / m ² .

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

The cushion layer is configured to be easily deformed when stress is applied to the image receiving layer, and in order to achieve the effect, a material having a low elastic modulus, a material having rubber elasticity, or a thermoplastic that is easily softened by heating. It is preferable to consist of resin. The elastic modulus of the cushion layer is preferably 0.5 MPa to 1.0 GPa, particularly preferably 1 MPa to 0.5 GPa, more preferably 10 to 100 MPa at room temperature. In addition, in order to entrap foreign substances such as dust, JIS
The penetration (25 ° C., 100 g, 5 seconds) determined by K2530 is preferably 10 or more. Further, the glass transition temperature of the cushion layer is 80 ° C. or lower, preferably 25 ° C. or lower, and the softening point is preferably 50 to 200 ° C. In order to adjust these physical properties, for example, Tg, a plasticizer can be suitably added to the binder.

Specific materials used as a binder for the cushion layer include rubbers such as urethane rubber, butadiene rubber, nitrile rubber, acrylic rubber, natural rubber, polyethylene, polypropylene, polyester, styrene-butadiene copolymer, ethylene -Vinyl acetate copolymer, ethylene-acrylic copolymer, vinyl chloride-vinyl acetate copolymer, vinylidene chloride resin, vinyl chloride resin with plasticizer, polyamide resin, phenol resin and the like.
In addition, although the thickness of a cushion layer changes with resin and other conditions to be used, it is 3-100 micrometers normally, Preferably it is 10-52 micrometers.

The image receiving layer and the cushion layer need to be adhered until the stage of laser recording, but in order to transfer the pixel to the image receiving sheet, it is preferable that the image receiving layer and the cushion layer are provided so as to be peelable. However, in the case of forming a color filter, it is not particularly necessary. However, when transferring to another support such as a glass plate if desired, the image receiving layer and the cushion layer are preferably provided so as to be peelable. In order to facilitate peeling, it is also preferable to provide a peeling layer with a thickness of about 0.1 to 2 μm between the cushion layer and the image receiving layer. If the film thickness is too large, the performance of the cushion layer becomes difficult to appear, and therefore it is necessary to adjust depending on the type of the release layer.
Specific examples of binders for the release layer include polyolefin, polyester, polyvinyl acetal, polyvinyl formal, polyparabanic acid, polymethyl methacrylate, polycarbonate, ethyl cellulose, nitrocellulose, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, and polyvinyl chloride. , Urethane resins, fluorine resins, polystyrenes, styrenes such as acrylonitrile styrene, and those obtained by crosslinking these resins, polyamides, polyimides, polyetherimides, polysulfones, polyethersulfones, aramids, etc., with a Tg of 65 ° C. or higher Resins and cured products of these resins are mentioned. As the curing agent, general curing agents such as isocyanate and melamine can be used.
When the binder for the release layer is selected according to the above physical properties, polycarbonate, acetal, and ethyl cellulose are preferable from the viewpoint of storage stability. When an acrylic resin is used for the image receiving layer, the release property is improved when the image after laser thermal transfer is retransferred. Particularly preferred.
In addition, a layer that has extremely low adhesion to the image receiving layer upon cooling can be used as the release layer. Specifically, it can be a layer mainly composed of a heat-melting compound such as waxes and a binder, or a thermoplastic resin.

Examples of the hot-melt 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.
Higher fatty acids, higher alcohols, higher fatty acid esters, amides, higher amines and the like can be added to such a release layer as necessary.
Another structure of the release layer is a layer having releasability by melting or softening when heated to cause cohesive failure. Such a release layer preferably contains a supercooling substance.
Examples of the supercooled substance include poly-ε-caprolactone, polyoxyethylene, benzotriazole, tribenzylamine, and vanillin.
Furthermore, in the peelable layer having another configuration, a compound that decreases the adhesion to the image receiving layer is included. Examples of such compounds include silicone resins such as silicone oil; fluorine resins such as Teflon (registered trademark) and fluorine-containing acrylic resins; polysiloxane resins; acetal resins such as polyvinyl butyral, polyvinyl acetal, and polyvinyl formal; polyethylene Examples thereof include solid waxes such as wax and amide wax; and fluorine-based and phosphate-based surfactants.
Examples of the method for forming the release layer include a blade coater, a roll coater, a bar coater, a curtain coater, a gravure coater, and other coating methods in which the above materials are dissolved in a solvent or dispersed in a latex form, an extrusion lamination method using hot melt, and the like. It can be applied and formed on the cushion layer. Alternatively, there is a method in which a material obtained by dissolving the raw material in a solvent or dispersed in a latex form on a temporary base is bonded to the cushion layer and the material applied by the above method, and then the temporary base is peeled off.

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

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

Binders used in the back layer include gelatin, polyvinyl alcohol, methyl cellulose, nitrocellulose, acetyl cellulose, aromatic polyamide resin, silicone resin, epoxy resin, alkyd resin, phenol resin, melamine resin, fluorine resin, polyimide resin, urethane resin , Acrylic resin, urethane-modified silicone resin, polyethylene resin, polypropylene resin, polyester resin, Teflon resin, polyvinyl butyral resin, vinyl chloride resin, polyvinyl acetate, polycarbonate, organic boron compounds, aromatic esters, fluorinated polyurethane, polyether General-purpose polymers such as sulfone can be used.
Using a crosslinkable water-soluble binder as a binder for the back layer is effective in preventing the matting agent from falling off and improving the scratch resistance of the back coat. It is also very effective for blocking during storage.
As the crosslinking means, any one or combination of heat, actinic light, pressure, etc. can be employed without particular limitation depending on the characteristics 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 provide adhesion to the support.

Organic or inorganic fine particles can be used as the matting agent preferably added to the back layer. Examples of the organic matting agent include polymethyl methacrylate (PMMA), polystyrene, polyethylene, polypropylene, fine particles of other radical polymerization polymers, and fine particles of condensation polymers such as polyester and polycarbonate.
The back layer is preferably provided at a weight of about 0.5 to 5 g / m ² . If it is less than 0.5 g / m ² , the coating property is unstable, and problems such as powdering off of the matting agent are likely to occur. Also, if the coating is applied greatly exceeding 5 g / m ² , the particle size of a suitable matting agent becomes very large, resulting in embossing of the image-receiving layer surface by back coating during storage, especially thermal transfer for transferring a thin image forming layer Then, omission and unevenness of the recorded image are likely to occur.
The matting agent preferably has a number average particle size 2.5 to 20 μm larger than the film thickness of the back layer alone. Among the matting agent, 8 [mu] m or more particles having a particle size of 5 mg / m ² or more is required, preferably 6~600mg / m ^2. This in particular improves foreign matter failures. Further, by using a narrow particle size distribution such that a value σ / rn (= coefficient of variation of the particle size distribution) obtained by dividing the standard deviation of the particle size distribution by the number average particle size is 0.3 or less, Defects generated by particles having an abnormally large particle size can be improved, and desired performance can be obtained with a smaller addition amount. The variation coefficient is more preferably 0.15 or less.

An antistatic agent is preferably added to the back layer in order to prevent adhesion of foreign matters due to frictional charging with the transport roll. Examples of the antistatic agent include a cationic surfactant, an anionic surfactant, a nonionic surfactant, a polymer antistatic agent, and conductive fine particles, as well as “11290 Chemical Products”, Chemical Industry Daily, 875- The compounds described on page 876 and the like are widely used.
As the antistatic agent that can be used in combination with the back layer, among the above substances, metal oxides such as carbon black, zinc oxide, titanium oxide, and tin oxide, and conductive fine particles such as organic semiconductors are preferably used. In particular, it is preferable to use conductive fine particles because the antistatic agent is not dissociated from the back layer, and a stable antistatic effect can be obtained regardless of the environment.
In addition, various activators, release agents such as silicone oil, fluorine-based resins, and the like can be added to the back layer in order to impart coatability and releasability.
The back layer is particularly preferable when the softening point measured by TMA (Thermomechanical Analysis) of the cushion layer and the image receiving layer is 70 ° C. or less.

  The TMA softening point is obtained by heating the measurement object 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 Corporation.

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 sheet or the image receiving layer are superposed.
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 superposing the image forming layer of the thermal transfer sheet and the image receiving sheet or the image receiving layer and passing them through a pressure heating roller. In this case, the heating temperature is preferably 160 ° C. or lower, or 130 ° C. or lower.

  As another method for obtaining a laminate, the above-described vacuum contact method is also preferably used. In the vacuum contact method, an image receiving sheet is first wound on a drum provided with a suction hole for evacuation, and then a thermal transfer sheet slightly larger in size than the image receiving sheet, while air is uniformly pushed out by a squeeze roller, the image receiving sheet It is the method of making it vacuum-adhere to. As another method, there is also a method in which the image receiving sheet is mechanically attached to the metal drum while being pulled, and a thermal transfer sheet is similarly attached to the metal drum while being mechanically pulled to be in close contact therewith. Among these methods, the vacuum adhesion method is particularly preferable because it does not require temperature control of a heat roller or the like and is easy to laminate quickly and uniformly.

Examples of the present invention will be described below, but the present invention is not limited to these examples. Unless otherwise specified in the text, “part” means “part by mass”.
Example 1
-1. 1. Preparation of laser thermal transfer sheet 1-1. Production of cushion layer

Composition of cushion layer forming coating solution 25 parts vinyl chloride-vinyl acetate copolymer (manufactured by Nissin Chemical Co., Ltd., MPR-TSL)
Plasticizer 6 functional acrylate monomers 12 parts (manufactured by Nippon Kayaku Co., Ltd., DPCA-120, molecular weight 1947)
0.4 parts of surfactant (Megafac F-177, manufactured by Dainippon Ink & Chemicals, Inc.)
75 parts of methyl ethyl ketone

  This was applied to a biaxially stretched PET base having a thickness of 100 μm, and the coating amount was adjusted so that the dry film thickness was about 20 μm.

1-2. Preparation of Photothermal Conversion Layer 1) Preparation of Coating Solution for Forming Photothermal Conversion Layer The following components were mixed while stirring with a stirrer to prepare a coating solution for forming a photothermal conversion layer.

Coating liquid composition Infrared absorbing dye (NK-2014, manufactured by Nippon Photosensitive Dye Co., Ltd.) 10 parts Binder (Rika Coat SN-20, manufactured by Shin Nippon Rika Co., Ltd.) 200 parts N-methyl-2-pyrrolidone 2000 parts Surfactant 1 part (Megafuck F-177, manufactured by Dainippon Ink & Chemicals, Inc.)

2) Formation of light-to-heat conversion layer on support surface After coating the above coating solution on the cushion layer coating surface using a spin coater (wheeler), the coated material is dried in an oven at 100 ° C. for 2 minutes. Then, a photothermal conversion layer was formed on the support. The obtained photothermal conversion layer had an absorption maximum in the vicinity of 830 nm in the wavelength range of 700 to 1000 nm, and its absorbance (optical density: OD) was measured with a Macbeth densitometer. The film thickness was 0.3 μm on average when the cross section of the photothermal conversion layer was observed with a scanning electron microscope.

1-3. Preparation of image-forming layer 3) Preparation of coating solution for forming image-forming layer After the following components were dispersed for 2 hours with a paint shaker (manufactured by Toyo Seiki Co., Ltd.), glass beads were removed, and a red pigment-dispersed mother liquor was prepared. Prepared.

Pigment-dispersed mother liquor composition 12.6 parts of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., Denkabutyral # 2000-L, Vicat softening point 57 ° C.) 20% by mass n-propyl alcohol solution coloring material Irgazine Red BPT (red) 24 parts Dispersing aid (Solsperse S-20000, manufactured by ICI) 0.8 parts n-propyl alcohol 110 parts Glass beads 100 parts

  The following components were mixed with stirring with a stirrer to prepare a red image forming layer forming coating solution.

Coating solution composition Pigment dispersion mother liquor 20 parts n-propyl alcohol 60 parts Surfactant 0.05 parts (Megafac F-176PF, manufactured by Dainippon Ink & Chemicals, Inc.)

  In the same manner, an image forming coating solution was prepared using copper phthalocyanine (green) pigment in a green color and Sudan blue (blue) in a blue color.

4) Formation of the red image forming layer on the surface of the light-to-heat conversion layer After the coating solution is applied to the surface of the light-to-heat conversion layer, the coating is dried in an oven at 100 ° C. for 2 minutes, A red image forming layer (pigment 64.2% by mass, polyvinyl butyral 33.7% by mass) was formed thereon. When measured in the same manner as described above, the film thickness was 2.5 μm on average. Through the above steps, a laser thermal transfer sheet was prepared in which a cushion layer, a photothermal conversion layer, and a red image forming layer were provided in this order on the support. Similarly, a laser thermal transfer sheet having a green image forming layer and a blue image forming layer was produced.

A laser thermal transfer sheet K having a layer thickness of 1.25 μm was prepared in the same manner as described above except that the following black image forming layer coating solution was used.
[Black pigment dispersion mother liquor composition]

Composition 1
・ 12.6 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
Pigment Black 7 (carbon black CI No. 77266) 4.5 parts (“Mitsubishi Carbon Black # 5”, manufactured by Mitsubishi Chemical Corporation, PVC blackness: 1)
・ Dispersing aid 0.8 parts ("Solsperse S-20000", manufactured by ICI Corporation)
・ 79.4 parts of n-propyl alcohol

Composition 2
・ 12.6 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
Pigment Black 7 (carbon black CI No. 77266) 10.5 parts (“Mitsubishi Carbon Black MA100”, manufactured by Mitsubishi Chemical Corporation, PVC blackness: 10)
・ Dispersing aid 0.8 parts ("Solsperse S-20000", manufactured by ICI Corporation)
・ 79.4 parts of n-propyl alcohol

  Next, the following components were mixed while stirring with a stirrer to prepare a black image forming layer coating solution.

[Coating solution composition for black image forming layer]
-Black pigment dispersion mother liquor 185.7 parts Composition 1: Composition 2 = 70: 30 (parts)
・ 11.9 parts of polyvinyl butyral (“S-REC B BL-SH”, manufactured by Sekisui Chemical Co., Ltd.)
Wax-based compound (stearic acid amide “Neutron 2”, manufactured by Nippon Seika Co., Ltd.) 1.7 parts (behenic acid amide “Diamid BM”, manufactured by Nippon Kasei Co., Ltd.) 1.7 parts (lauric acid) Amide “Diamid Y” manufactured by Nippon Kasei Co., Ltd.) 1.7 parts (palmitic acid amide “Diamid KP” manufactured by Nippon Kasei Co., Ltd.) 1.7 parts (Erucaic acid amide “Diamid L-200”) , Nippon Kasei Co., Ltd.) 1.7 parts (Oleamide "Diamid O-200", Nippon Kasei Co., Ltd.) 1.7 parts Rosin 11.4 parts ("KE-311", Arakawa Chemical) (Made by Co., Ltd.)
(Component: resin acid 80-97%; resin acid component: abietic acid 30-40%, neoabietic acid 10-20%, dihydroabietic acid 14%, tetrahydroabietic acid 14%)
-Surfactant 2.1 parts ("Megafac F-176PF", solid content 20%, manufactured by Dainippon Ink & Chemicals, Inc.)
Inorganic pigment 7.1 parts ("MEK-ST", 30% methyl ethyl ketone solution, manufactured by Nissan Chemical Co., Ltd.)
・ 1050 parts of n-propyl alcohol ・ 295 parts of methyl ethyl ketone

-3. Preparation of image-receiving sheet A glass substrate having a thickness of 1.1 mm was used as the image-receiving sheet support, and the surface was surface-treated with a 0.3% aqueous solution of a silane coupling agent (KBE-903 manufactured by Shin-Etsu Chemical Co., Ltd.). . Next, an image receiving layer (thickness: 1 μm) was provided from the following image receiving layer coating solution using a spin coater on the treated surface.

Image receiving layer coating solution polyvinyl butyral (Denka Butyral # 2000-L, manufactured by Denki Kagaku Kogyo Co., Ltd.)
16 parts surfactant 0.5 parts (Megafac F-177, manufactured by Dainippon Ink & Chemicals, Inc.)
100 parts of n-propyl alcohol

-4. Image formation by laser thermal transfer sheet The image receiving sheet (25 cm × 35 cm) was adsorbed on a flat bed provided with a suction hole for vacuum suction having a diameter of 1 mm (one surface density in an area of 3 cm × 3 cm). Next, the 30 cm × 40 cm thermal transfer sheet K is stacked so as to protrude evenly from the image receiving sheet, and the thermal transfer sheet is closely adhered so that air is sucked into the suction holes while squeezing with a squeeze roller, and the image receiving sheet and the thermal transfer sheet are laminated. did. The degree of vacuum in the state where the suction holes were blocked was −150 mmHg (≈81.13 kPa) with respect to 1 atmosphere.
Next, the flat bed is moved, and a semiconductor laser beam having a wavelength of 830 nm is focused on the surface of the laminated body on the flat bed from the outside so as to be a 7 μm spot on the surface of the photothermal conversion layer, and the flat bed is moved. Laser image recording on the laminate was performed while moving in the direction perpendicular to the direction (main scanning direction) (sub-scanning). Laser recording was performed by irradiating an image corresponding to the color filter image shown in FIG. 3 from the thermal transfer sheet side imagewise with laser light. a was set to 150 μm, b was set to 100 μm, and c was set to 20 μm. The laser irradiation conditions are as follows.

Laser power: 110mW
Main scanning speed: 4 m / sec Sub-scanning pitch (sub-scanning amount per channel): 10 μm
Temperature and humidity: 25 ° C, 50% RH

  When the laminate on which the above laser image recording was performed was removed from the flat bed and the image receiving sheet and the thermal transfer sheet K were manually peeled off, only the laser irradiation portion of the image forming layer was transferred from the transfer sheet to the image receiving sheet. It was confirmed that In the same manner as described above, images of the laser thermal transfer sheets R, G, B, and K were transferred, and images (R, G, B, K) were formed on the image receiving sheet to obtain a color filter. As for K, a film thickness of 2.5 μm was obtained by recording twice.

Comparative Example In Example 1, images (R, G, B) were formed in the same manner as in Example except that the layer thickness of the laser thermal transfer sheet K was the same as that of the laser thermal transfer sheet B and the laser thermal transfer sheet K was transferred once. , K) to obtain a color filter.

The color filters obtained in Examples and Comparative Examples were evaluated as follows and are shown in Table 1.
<Evaluation method>

a. Image quality: Judged by the shape of the edge portion.
A: The end is a straight line. The angle is 90 degrees and there are no debris.
○: Some deformation is seen at the end, but it is almost straight and there are no debris.
(Triangle | delta): A deformation | transformation is seen in an edge part and a corner becomes round.
X: Deformation of the end is large, the corners are rounded, and fragments are generated.

b. Density: The transmission density (Macbeth densitometer TD904) of the image (R, G, B, K) is measured.
A: 3.0 or more
○: 2.8 to less than 3.0
Δ: 2.6 to less than 2.8
X: Less than 2.6

c. Step: The step between the K color and the BGR pixel is measured with an α step thickness meter.
A: Less than 0.1 μm
○: 0.1 μm to less than 0.2 μm
Δ: 0.2 μm to less than 0.3 μm
×: 0.3 μm or more

  It can be seen that the example is superior to the comparative example with respect to the edge shape, optical density and step of the image (R, G, B, K).

It is a figure explaining the outline of the mechanism of multicolor image formation by thin film thermal transfer using a laser. It is a figure which shows the structural example of the recording apparatus for laser thermal transfer. An example of forming a pixel of a color filter is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording apparatus 2 Recording head 3 Subscanning rail 4 Recording drum 5 Thermal transfer sheet loading unit 6 Image receiving sheet roll 7 Conveyance roller 8 Squeeze roller 9 Cutter 10 Thermal transfer sheet 10R, 10G, 10B Thermal transfer sheet roll 12 Support body 14 Photothermal conversion layer 16 Image Formation layer 20 Image receiving sheet 22 Image receiving sheet support 24 Image receiving layer 30 Laminate 31 Discharge stand 32 Disposal port 33 Discharge port 34 Air 35 Disposal box 41 Color filter 42 Red filter pixel 43 Green filter pixel 44 Blue filter pixel 45 Black matrix

Claims (4)

Heat conversion layer containing a polyimide resin as at least a binder on a support, red (R), green (G), and the four laser thermal transfer sheet having an image forming layer of blue (B) or black (K), the image receiving A method of forming an image composed of R, G, B, and K by superimposing a sheet and transferring an image forming layer onto the image receiving sheet by irradiating laser light imagewise from the thermal transfer sheet side. A method for forming a color filter, wherein at least one of the laser thermal transfer sheets is transferred twice or more.   2. The method for forming a color filter according to claim 1, wherein the image forming layer of the laser thermal transfer sheet having the K image forming layer is transferred first and last.   3. The color filter forming method according to claim 1, wherein the image forming layer has a thickness of 0.1 to 5 [mu] m.   The color filter manufactured by the formation method of the color filter of any one of Claims 1-3.

Images