JPH04327983A - Thermal transfer sheet and image forming method - Google Patents

Abstract

PURPOSE:To record an image by a dry system in a perfect bright chamber and to transfer it in high resolution by a method wherein a photothermal conversion layer and an image forming layer containing a color material are successively laminated on a surface of a base material and after radiating high density energy light like an image, an image receiving material is adhered to an image forming layer and the image forming layer in a light irradiated area is transferred to the image receiving material by separation. CONSTITUTION:A co-vapor deposition layer of low melting metals such as In, Sn, etc., and SnS or the like should be especially preferable as a photothermal conversion layer 3 to be formed on a film like or a plate like base material 2. An image forming layer 4 to be formed on the photothermal conversion layer 3 is formed by applying suspension or the like of color materials such as a pigment, a dye, etc., and a binder or the like. When high density energy light of laser beams or the like is radiated to this thermal transfer sheet from the base material 2 side, metals in an irradiated part 3A of the photothermal conversion layer 3 are melted to form a cavity. Then an optional image receiving material 5 containing plain paper is adhered onto the image forming layer 4 via adhesives. When separated, a light irradiation corresponding part 4A of the image forming layer 4 is cut on a boundary to a non-irradiation corresponding part 4B to be transferred to the image receiving material 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel image forming method by imagewise irradiation with high-density energy light and a thermal transfer sheet used in this image forming method. In particular, the present invention relates to a method for forming a multicolor image that is peelable and developable by laser recording and is suitable for creating color proofs in the printing field, and a thermal transfer sheet used therein.

0002

2. Description of the Related Art Conventionally, an image forming method (hereinafter referred to as a thermal image forming method) is known in which an image is recorded and formed by scanning and irradiating high-density energy light in an imagewise manner. This thermal image forming method has the characteristics that an image can be recorded in a completely bright room without requiring a dark room, and that it can be processed dryly without using a developer.

As such a thermal image forming method, for example, Japanese Patent Publication No. Hei 2-501552 discloses a thermal image forming method in which the image is formed from a material transparent to the image forming radiation and heated to a predetermined elevated temperature. support having an image-forming surface layer that can be liquefied and made flowable: a layer of porous or particulate image-forming material coated on the surface layer, which image-forming material a layer exhibiting a cohesive strength greater than the adhesion strength between the forming material and the surface layer, at least one of the materials in the layer absorbs the radiation and forms an image forming surface. converting the layer material into thermal energy capable of liquefying the surface layer material, which when liquefied exhibits capillary flow into adjacent portions of the imaging material;
Imaging methods are disclosed that utilize thermal imaging elements whereby upon cooling of the imaging surface layer, the entire layer of imaging material is substantially fixed to the support.

That is, the image forming method disclosed in Japanese Patent Publication No. Hei 2-501552 involves forming an image on a support made of a material transparent to the image forming radiation at a portion irradiated with the radiation. This is a method of forming an image on the surface of a support by bonding the layers with an adhesive force that is stronger than the adhesive force with the image forming layer in the areas not irradiated with radiation. In this method, images can be recorded by scanning using high-density energy light such as laser light as the image-forming irradiation beam. Because of these functions, it has been difficult to form multicolor images using a single wavelength light source such as a semiconductor laser.

[0005]

[Problem to be solved by the invention] Images can be recorded dry in a completely bright room, and images containing any coloring material can be easily transferred and formed at high resolution onto any image receptor including plain paper. An image forming method is provided.

[0006]

[Means for Solving the Problems] The present invention provides a structure in which a photothermal conversion layer containing a photothermal conversion substance is provided on the surface of a support, and an image forming layer containing a coloring material is provided on the photothermal conversion layer. By irradiating the thermal transfer sheet with high-density energy light in an imagewise manner, the bonding force between the photothermal conversion layer and the image forming layer in the high-density energy light irradiation area is reduced, and then the image receptor is bonded to the image-forming layer via an adhesive. Then, the support and image receptor are separated, and the image forming layer in the areas not irradiated with high-density energy light remains on the photothermal conversion layer, and the image-forming layer in the areas irradiated with high-density energy light is pressed onto the image forming layer. This is an image forming method characterized by forming an image on an image receptor by transferring only a portion onto the surface of the image receptor.

Another aspect of the present invention is a thermal transfer sheet comprising a light-to-heat conversion layer containing a light-to-heat conversion substance, an image forming layer containing a coloring material, an adhesive layer, and an image receptor provided on the surface of a support in this order. The bonding force between the support and the photothermal conversion layer and the bonding force between the photothermal conversion layer and the image forming layer are greater than the bonding force between the image forming layer and the image receptor, and The thermal transfer sheet is characterized in that the bonding force between the photothermal conversion layer and the image forming layer becomes smaller than the bonding force between the image forming layer and the image receptor when irradiated with light.

Still another aspect of the present invention provides, on the surface of the support, a light-to-heat converting layer containing a light-to-heat converting substance, an image forming layer containing a coloring material,
By irradiating a thermal transfer sheet formed with an adhesive layer and an image receptor in this order with high-density energy light in an imagewise manner, the difference between the photothermal conversion layer and the image forming layer in the high-density energy light irradiation area is The bonding force is reduced, and then the support and image receptor are separated, leaving the image forming layer in the area not irradiated with high-density energy light on the photothermal conversion layer, and only the image-forming layer portion in the area irradiated with high-density energy light is removed. An image forming method is characterized in that an image is formed on an image receptor by remaining bonded to the surface of the image receptor.

Preferred embodiments of the present invention are as follows.

(1) The above image forming method, wherein the support is made of a material that is transparent to high-density energy light.

(2) The above-mentioned image forming method, wherein the light-to-heat conversion layer is a metal (including alloy and metal compound) thin film formed by a vacuum film forming method.

(3) The above image forming method, wherein the coloring material is carbon black, an inorganic pigment, an organic pigment, a dye, or the like.

(4) The thermal transfer sheet further includes an undercoat layer between the support and the light-to-heat conversion layer, and an intermediate layer containing a bubble generator, a polymer, etc. between the light-to-heat conversion layer and the image forming layer. The above image forming method is characterized in that:

(5) The image forming method described above, wherein the imagewise irradiation of the high-density energy light is performed by scanning a laser beam.

(6) The image forming method described above, wherein the imagewise irradiation of the high-density energy light is performed by applying light from a xenon flash lamp through an image mask.

(7) The image forming method described above, characterized in that the imagewise irradiation of the high-density energy light is performed from the support side of the thermal transfer sheet.

The present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view schematically showing a cross section of an example of a thermal transfer sheet used in the image forming method of the present invention.

In FIG. 1, a thermal transfer sheet 1 includes a light-to-heat conversion layer 3 provided on a support 2, and an image forming layer 4 provided thereon.

The support 2 is not particularly limited as long as it is in the form of a film or a plate, and may be made of any material. Examples of the material for the support 2 generally include polymeric compounds such as polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and styrene-acrylonitrile copolymer. Particularly preferred are polycarbonate, polyethylene terephthalate, and the like. Moreover, the thickness of the support body 2 is
In the case of a film, it is generally 10 to 400 μm, especially 50 μm.
It is preferable that it is 200 micrometers. Further, depending on the application, a glass plate, a metal plate, etc. can also be suitably used as the support body 2.

The photothermal conversion layer 3 contains a photothermal conversion material, and the photothermal conversion material contains a material that generates heat upon receiving high-density energy light, and is perforated by the heat.
Any substance can be used without particular limitation as long as it changes in volume or abla-tion.

[0021] Examples of the above-mentioned photothermal conversion substances include metals, alloys, and metal compounds. Preferred examples of this metal include metals with low melting points such as Sn, In, Al, Bi, Ga, Te, and Sb, and alloys thereof; metal compounds include metal sulfides such as SnS and GeS; In2O
In addition to oxides such as 3, SnO2, and TeO2, halides and the like can be mentioned. A particularly preferred example of the photothermal conversion material is a co-deposited layer of a low melting point metal such as In or Sn and SnS or the like. The light-to-heat conversion layer 3 containing a metal (hereinafter, alloys and metal compounds are included unless otherwise specified) is formed by depositing the above-mentioned metal onto a support by vacuum deposition, sputtering, ion plating, etc. It is preferable that the metal thin film is formed by vapor deposition using a film forming method. In this case, the thickness of the photothermal conversion layer 3 is generally 0.01~
Preferably, it is 0.5 μm.

The surface of the light-to-heat conversion layer 3 (support side or image forming layer side) is coated with, for example, a chalcogen compound (for example, S
It is preferable to provide an antireflection layer made of a material having a refractive index different from that of metal, such as nS, GeS, etc.).

The image forming layer 4 contains a coloring material, and the coloring material includes carbon black, graphite, inorganic pigments (such as titanium oxide and zinc oxide), and organic pigments (such as titanium oxide and zinc oxide).
Examples include phthalocyanine-based, azo-based, anthraquinone-based, etc.), organic dyes (eg, phthalocyanine-based, azo-based, triphenylmethane-based, cyanine-based, etc.), and the like. Further, as the coloring material, not only dyes and pigments but also finely powdered metals (eg, aluminum, nickel, etc.) can also be used.

The image forming layer 4 includes polystyrene, polyvinylpyrrolidone, cellulose butyl acetate, methylcellulose, gelatin, polyvinyl alcohol, a copolymer of methacrylic acid and benzyl methacrylate, a styrene-maleic acid copolymer and its esterified resin, etc. It may also contain a binder such as. Particularly preferred as a binder is a copolymer of methacrylic acid and benzyl methacrylate. The image forming layer 4 may further contain a stabilizer such as a photofading inhibitor.

The image forming layer 4 can be formed by suspending the above-mentioned coloring material, binder, etc. in a suitable solvent, applying the resulting suspension onto the light-to-heat conversion layer, and drying it. can. The thickness of the imaging layer 4 varies depending on the use of the image receptor imaged by the method of the present invention and may be any thickness, but is generally 0.05 to 10 μm, particularly 0.2 to 1.0 μm. It is preferable that

FIGS. 2 to 4 illustrating the image forming method of the present invention
Explain with reference to. In order to simplify the explanation, Figure 2
In 4 to 4, a case will be described in which a thermal transfer sheet in which the light-to-heat conversion layer 3 is a thin metal film is used.

In the present invention, first, the thermal transfer sheet 1
irradiates with high-density energy light. FIG. 2 shows an irradiation mode of high-density energy light. In FIG. 2, the thermal transfer sheet 1 is imagewise irradiated with high-density energy light HEL from the support 2 side.

[0028] As the high-density energy light, laser light,
Examples include light from a xenon flash lamp. As a method for image-wise irradiation with high-density energy light HEL, it is preferable to use scanning when using a laser beam, or by irradiating the entire surface through an image mask when using light from a xenon flash lamp. It is preferable to use laser light as the high-density energy light because it can directly perform image-wise irradiation using digital data from an image processing system. As the laser, a gas laser such as an argon ion laser, a solid laser such as a YAG laser, a semiconductor laser, etc. can be used.

When the high-density energy light HEL is irradiated from the side of the support 2, the high-density energy light HEL transmitted through the support 2 enters the photothermal conversion layer 3, and the metal in the irradiated portion 3A of the photothermal conversion layer 3 is melted. . The molten metal gathers into a large lump 3a, and the irradiated portion 3A of the photothermal conversion layer 3 disappears, forming a cavity. As a result, the irradiation corresponding portion 4A of the image forming layer 4 and the support 2 are no longer bonded. On the other hand, since the non-irradiated portion 3B of the photothermal conversion layer 3 that is not irradiated with the high-density energy light HEL remains unchanged, the non-irradiated portion 4B of the image forming layer 4 remains bonded to the support 2 via the photothermal conversion layer 3. are doing.

Next, as shown in FIG. 3, an image receptor 5 is adhered onto the image forming layer 4 with an adhesive. Image forming layer 4
The adhesion between the image receptor 5 and the image receptor 5 may be carried out by using an image receptor in which an adhesive layer is provided on one side of the image receptor in advance. This may also be done by applying an adhesive to the adhesive surface. The bonding force between the image receptor 5 and the image forming layer 4 needs to be smaller than both the bonding force between the photothermal conversion layer 3 and the support 2 and the bonding force between the image forming layer 4 and the photothermal conversion layer 3. .

Next, as shown in FIG. 4, the support 2 and the image receptor 5 are separated. As a result, the image receptor 5 and the image forming layer 4
Since the bonding force between the photothermal conversion layer 3 and the support 2 and the bonding force between the image forming layer 4 and the photothermal conversion layer 3 are smaller than the bonding force between the photothermal conversion layer 3 and the photothermal conversion layer 3, the non-irradiation corresponding portion 4B of the image forming layer 4 The irradiation-responsive portion 4A of the image-forming layer 4, which is separated from the image receptor 5 and remains on the support 2, remains bonded to the image-receptor 5 because there is no irradiation-response portion 3A of the photothermal conversion layer 3, and remains on the irradiation-responsive portion of the image-forming layer 4. 4
Shear failure occurs at the boundary between A and the non-irradiation corresponding part 4B,
It separates from the thermal transfer sheet 1.

The image receptor 5 has the following functions: (1) adhering and peeling off the image forming layer in the irradiated area and leaving the image forming layer in the non-irradiated area on the photothermal conversion layer; The function of the part (image) of the forming layer as the final support, or (
3) Functions as a temporary support for images. The image receptor 5 needs to maintain the mechanical strength necessary to fulfill these functions, and also needs to have appropriate adhesion to the image forming layer in order to fulfill the function (1). In order to provide the image receptor 5 with such mechanical strength and appropriate adhesiveness,
An adhesive layer is provided on the surface of the support having high mechanical strength.

As the support for the image receptor 5, the materials described for the support 2 above can be used. Furthermore,
Plain paper, paper with surface treatment such as coating, etc. can also be used. Moreover, as the adhesive layer of the image receptor 5,
It is generally formed by mixing an organic polymer compound with a tackifier such as rosin, a plasticizer, etc., and is particularly used in the adhesive layer of pressure-sensitive adhesive tapes to achieve appropriate adhesive strength. Those that have been prepared are preferably used.

Function (3) of the image receptor 5 in the present invention described above
) is used, for example, in the color proof creation process in printing. There are generally two types of color proofing methods: an overlay method and a surprint method. In the former case, image receptors on which images of each color, such as cyan, magenta, yellow, and black, are formed are aligned on, for example, white paper, and then superimposed to form a color image. In the latter case, each image on the image receptor is laminated and transferred to a proofing support (for example, printing paper). In such applications, the adhesion between the image receptor 5 and the image forming layer 4 requires appropriate releasability and adhesion between the transferred color images so that they can be transferred to a proofing support.

[0035] As the material of the image receptor having such a function, the examples described in Japanese Patent Application Laid-open Nos. 60-31238 and 60-40847 are preferably used. Images of cyan, magenta, yellow, black, etc. formed on such image receptors are transferred onto printing paper using a laminator or the like, and are used for purposes such as proofreading.

The thickness of the image receptor 5 is generally preferably 5 μm or more, particularly 25 μm or more. If the thickness is too small, the so-called stiffness will be lost, resulting in poor handling and dimensional accuracy. If the thickness is large in sheet form, generally 200μm
The following is preferable from the viewpoint of ease of handling, but there is no particular upper limit. Depending on the application, it may be necessary to transfer the image to a plate-like object, and the optimum thickness is appropriately selected taking into account the application.

As described above, the portion of the image forming layer corresponding to the image irradiation with the high-density energy light HEL is transferred to the image receptor 5, and an image is formed by the irradiation with the high-density energy light HEL. become.

In FIG. 2, high-density energy light HE
Although the mode in which L is irradiated from the side of the support 2 is shown, the material constituting the image forming layer 4 is transparent to the high-density energy light HEL and is not affected by adverse effects such as discoloration and deterioration. In some cases, it is also possible to irradiate from the side of the image forming layer 4. Generally, high-density energy light HE
It is preferable to irradiate L from the support 2 side.

FIG. 5 shows another aspect of the change in the light-to-heat conversion layer 3 when the thermal transfer sheet 1 is irradiated with the high-density energy light HEL. In FIG. 5, high-density energy light HE
When L is irradiated from the support 2 side with an appropriate intensity, the support 2
The high-density energy light HEL that has passed through is incident on the photothermal conversion layer 3, and a part of the metal is melted while the antireflection layer in the irradiated portion 3C of the photothermal conversion layer 3 is not melted. Even if the antireflection layer does not melt, even if only a part of the metal melts, the bonding force between the irradiated portion 4C of the image forming layer 4 and the irradiated portion 3C of the photothermal conversion layer 3 will be lower than that of the non-irradiated portion of the image forming layer 4. The bonding force between the corresponding portion 4B and the non-irradiated portion 3B of the photothermal conversion layer 3 is lower than that.

Therefore, when the image receptor 5 and the support 2 are separated in a later step, the non-irradiation corresponding portion 4B of the image forming layer 4 is separated from the image receptor 5 and placed on the support 2, as shown in FIG. The irradiated portion 4C of the image forming layer 4 is peeled off from the irradiated portion 3C of the photothermal conversion layer 3 and remains bonded to the image receptor 5, and the irradiated portion 4C of the image forming layer 4 is separated from the non-irradiated portion 4B. Shear failure occurs at the boundary and the sheet separates from the thermal transfer sheet 1. As a result, an image is formed on the image receptor 5 consisting of the image forming layer portion corresponding to the image irradiation with the high density energy light HEL. When irradiated with high-density energy light, the bonding strength between the irradiated portion 3C of the photothermal conversion layer 3 and the corresponding portion of the support 2 may also be reduced, but even in that case, the bonding force between the irradiated portion 3C of the photothermal conversion layer 3 and the corresponding portion of the support 2 may be reduced. By forming the thermal transfer sheet 1 so that the bonding force with the photothermal conversion layer 3 is stronger than the bonding force between the photothermal conversion layer 3 and the image forming layer 4, the irradiated portion 3C of the photothermal conversion layer 3 becomes an image receptor. 5 can be prevented from being transferred. In this way, it is possible to form an excellent image on the image receptor without sufficiently removing the photothermal conversion layer.

As is clear from the above explanation, in the present invention, high-density energy light is imagewise irradiated onto the thermal transfer sheet having the above-mentioned structure, and photothermal conversion occurs in the area irradiated with the high-density energy light. It is a method of forming an image on an image receptor that corresponds to imagewise irradiation with high density energy light by reducing the bonding strength between the layers and the imaging layer.

FIG. 6 is a cross-sectional view schematically showing another example of the thermal transfer sheet used in the image forming method of the present invention.

In FIG. 6, the thermal transfer sheet 11 is constructed by providing an undercoat layer 13, a light-to-heat conversion layer 14, an intermediate layer 15, an image forming layer 16, and a protective layer 17 on a support 12 in this order. The support 12, the photothermal conversion layer 14, and the image forming layer 16 are the same as the support 2, the photothermal conversion layer 3, and the image forming layer 4 described in FIG.

In FIG. 6, the undercoat layer 13 is made of polyester, chlorinated polyethylene, nitrocellulose, polymethyl methacrylate, polyisobutyl methacrylate, acrylic acid/methacrylic acid copolymer, styrene/maleic anhydride copolymer, polyvinyl alcohol. , N-methylolacrylamide, styrene/vinyltoluene copolymer, chlorosulfonated polyethylene, polyvinyl chloride, vinyl acetate/vinyl chloride copolymer, ethylene/vinyl acetate copolymer, polycarbonate, etc. Preferably, it can be formed by applying and drying a solution of these substances. By forming the undercoat layer 13, the sensitivity of the thermal transfer sheet 11 to high-density energy light can be increased. The thickness of the undercoat layer 13 is generally 0.01 to 3 μm, particularly 0.03 μm.
It is preferable that it is 0.5 micrometer.

The intermediate layer 15 is preferably made of a bubble generator such as diazo or azide, or a polymer compound such as polyester, nitrocellulose, chlorinated polyethylene, or polyisobutyl methacrylate, and is similar to the undercoat layer. This has the effect of increasing the sensitivity of the thermal transfer sheet 11 to high-density energy light. The thickness of the intermediate layer 15 is generally 0.
．． It is preferably 0.02 to 2 μm, particularly 0.05 to 0.5 μm.

The protective layer 17 is made of a polymer compound such as polyvinyl butyral, polyvinyl alcohol, polymethyl methacrylate, polyamide, polyvinylpyrrolidone, vinyl acetate/vinyl chloride copolymer, or ionomer resin (for example, Chemipearl). , can be formed by coating in the same manner as the undercoat layer, or can be formed by coating a preformed film of these polymer compounds. By providing the protective layer 17, it is possible to prevent the image forming material from scattering during irradiation with high-density energy light and to facilitate the transfer of the image forming layer to the image receptor. The thickness of the protective layer 17 is generally 0.05 to 3 μm, particularly 0.2 μm.
It is preferable that it is -1.0 micrometer.

Next, another thermal transfer sheet of the present invention, namely:
A thermal transfer sheet in which a photothermal conversion layer containing a photothermal conversion substance, an image forming layer containing a coloring material, an adhesive layer, and an image receptor are provided in this order on the surface of a support. The bonding force between the photothermal conversion layer and the image forming layer is greater than the bonding force between the image forming layer and the image receptor, and the bonding force between the photothermal conversion layer and the image forming layer is greater than the bonding force between the image forming layer and the image receptor. A thermal transfer sheet characterized in that the bonding force with the image forming layer is smaller than the bonding force between the image forming layer and the image receptor will be described.

FIG. 7 is a sectional view schematically showing a cross section of an example of the thermal transfer sheet of the present invention. In Figure 7,
The thermal transfer sheet 21 has a light-to-heat conversion layer 23 on a support 22.
An image forming layer 24 is provided thereon, an adhesive layer 25 is provided thereon, and an image receptor 26 is provided thereon.

The support 22, the photothermal conversion layer 23, the image forming layer 24, the adhesive layer 25, and the image receptor 26 are the support 2, the photothermal conversion layer 3, and the photothermal conversion layer 3, which have been explained in detail with reference to FIGS. The image forming layer 4, the adhesive layer, and the image receptor 5 are similar to each other. The bonding force between the support 22 and the photothermal conversion layer 23 and the bonding force between the photothermal conversion layer 23 and the image forming layer 24 are as follows:
It is stronger than the bonding force between the image forming layer 24 and the image receptor 26, and by irradiation with high-density energy light,
The relationship is such that the bonding force between the photothermal conversion layer 23 and the image forming layer 24 is smaller than the bonding force between the image forming layer 24 and the image receptor 26.

Since the thermal transfer sheet 21 is constructed as described above, the image can be transferred to the image receptor 26 by separating the image receptor 26 from the support 22 after imagewise exposing the thermal transfer sheet 21 to high-density energy light. What can be formed is
It will be easily understood from the detailed description with reference to FIGS. 1-5.

[0051] In another image forming method of the present invention, a photothermal conversion layer containing a photothermal conversion substance, an image forming layer containing a coloring material, an adhesive layer, and an image receptor are provided in this order on the surface of a support. By irradiating the thermal transfer sheet formed by the image forming method with high-density energy light in an imagewise manner, the bonding force between the light-to-heat conversion layer and the image forming layer in the high-density energy light irradiation area is reduced,
After that, the support and the image receptor are separated, leaving the image forming layer in the area not irradiated with high-density energy light on the photothermal conversion layer,
This image forming method is characterized in that an image is formed on an image receptor by leaving only the portion of the image forming layer in the area irradiated with high-density energy light bonded to the surface of the image receptor. This image forming method will be referred to as an image forming method (B) to distinguish it from the image forming method described with reference to FIGS. 1 to 5 (referred to as an image forming method (A)).

That is, the image forming method (B) is a method of forming an image using another thermal transfer sheet of the present invention as described above.

Image forming method (A) is as shown in FIG. 1, in which a thermal transfer sheet 1 is imagewise irradiated with high-density energy light, an image receptor 5 is adhered, and then the support and the image receptor are separated to form an image. In contrast, in image forming method (B), high-density energy light is irradiated imagewise on a thermal transfer sheet 21 on which a thermal transfer sheet 1 and an image receptor 5 are adhered in advance, and then the image is formed on a support. This is a method of separating the body and image receptor to form an image on the image receptor.

Therefore, the specific steps and image forming mechanism of the image forming method (B) have been explained with reference to FIGS. 2 to 4 (in FIG. 2, the image receptor 5 is adhered to the thermal transfer sheet The other thing is that you use the one that is the same).

[0055]

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples.

[Example 1] A 0.5% by weight solution of chlorinated polyethylene in methyl ethyl ketone was coated on a polyethylene terephthalate support (thickness: 100 μm) using a spin coater (Whaler) and coated at 100°C. Dry for 2 minutes to form a chlorinated polyethylene film (thickness: 0.05 μm).
on which a tin sulfide/tin layer (layer thickness: 60 nm) is formed.
) was deposited to form a photothermal conversion layer.

On the other hand, a coating solution for an image forming layer having the following composition was prepared. (Mother liquor A) Benzyl methacrylate-methacrylic acid copolymer 20 parts by weight Methyl ethyl ketone
80 parts by weight (coating liquid) Mother liquid A
110 parts by weight methyl ethyl ketone
40 parts by weight methyl cellosolve acetate 2
5 parts by weight Cyanine Blue 4920 12
．． 2 parts by weight (manufactured by Dainichiseika Chemical Co., Ltd.) Florado FC-430 2 parts by weight (manufactured by Sumitomo 3M Ltd.)

[0058] On the photothermal conversion layer, the coating liquid for the image forming layer was applied to a thickness of 0.5 μm using a Whaler.
The image forming layer (optical density 1.0,
A thermal transfer sheet was prepared by forming a Macbeth densitometer (white light).

This thermal transfer sheet was irradiated with laser light from an argon laser (300 mW, scan speed 38 m/s, beam diameter 10 μm). Next, using a roller (4.5 kg/m2) heated to 80°C, a color art image receiving sheet (manufactured by Fuji Photo Film Co., Ltd., CR-T3) was applied as an image receptor to the thermal transfer sheet at a speed of 900.
mm/min, and the receiver was peeled off from the thermal transfer sheet at room temperature. An image (negative type) corresponding to the laser beam irradiation was formed on the image receptor.

Next, when the image formed on the image receptor was transferred to printing paper, a good image with a resolution of 10 μm was obtained.

[Example 2] The same procedure as in Example 1 was used, except that 12.2 parts by weight of Seika Fast Carmine 1483 (manufactured by Dainichiseika Chemical Industry Co., Ltd.) was used instead of cyan blue 4920 used in Example 1. A thermal transfer sheet was prepared in the same manner as above.

Using this thermal transfer sheet, irradiation with laser light, image formation on an image receptor, and transfer to printing paper were performed in the same manner as in Example 1, and a good image was obtained. .

[Example 3] On the image forming layer of a thermal transfer sheet prepared in the same manner as in Example 1, a coating liquid for a protective layer having the following composition was applied in the same manner as in the formation of the image forming layer. Thermal transfer sheet A was prepared by drying and forming a protective layer (thickness: 0.5 μm).

(Coating liquid composition for protective layer) Ionomer resin 3
7 parts by weight (manufactured by Mitsui Petrochemical Industries, Ltd., Chemipearl S-
100) water
318 parts by weight surfactant
30 parts by weight (Surflon S-121, manufactured by Asahi Glass Co., Ltd.)

Using this thermal transfer sheet A, irradiation with laser light, image formation on an image receptor, and transfer to printing paper were performed in the same manner as in Example 1, and a good blue image was obtained. It was done.

Separately, a protective layer was formed on the image forming layer of a thermal transfer sheet prepared in the same manner as in Example 2, in the same manner as in the preparation of thermal transfer sheet A, to prepare thermal transfer sheet B.

Using thermal transfer sheet B, an image was formed on the image receptor in the same manner as in the case of thermal transfer sheet A, and the magenta image formed on the image receptor was transferred onto the printing paper onto which the blue image had been transferred. However, a superimposed image of blue and magenta two-color transfer images joined by a protective layer was formed.

[0068]

INDUSTRIAL APPLICABILITY The image forming method of the present invention has a remarkable effect in that an image containing any coloring material can be easily formed on any image receptor with high resolution. In the image forming method of the present invention, since the light-to-heat conversion layer and the image forming layer for forming an image are functionally separated in the thermal transfer sheet used, it is possible to form an image of any hue that does not absorb laser light, etc., and has a high When irradiating density energy light from the support side of the thermal transfer sheet, the optical density of the image recording layer can be used, so it is possible to reduce the layer thickness of the photothermal conversion layer and use low power high density energy light. Furthermore, it is possible to achieve the effect of exhibiting high resolution.

The image forming method of the present invention is particularly advantageous when used in the production of direct digital color proofs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing a cross section of an example of a thermal transfer sheet used in the image forming method of the present invention.

FIG. 2 is a cross-sectional view showing an example of a state in which high-density energy light is irradiated in the image forming method of the present invention.

FIG. 3 is a sectional view showing how an image receptor is adhered to a thermal transfer sheet in the image forming method of the present invention.

FIG. 4 is a sectional view showing a state where the thermal transfer sheet and the image receptor are separated in the image forming method of the present invention.

FIG. 5 is a cross-sectional view showing another example of a state in which high-density energy light is irradiated in the image forming method of the present invention.

FIG. 6 is a sectional view schematically showing a cross section of another example of a thermal transfer sheet used in the image forming method of the present invention.

FIG. 7 is a cross-sectional view schematically showing a cross section of another example of a thermal transfer sheet of the present invention.

[Explanation of symbols]

1 Thermal transfer sheet 2 Support 3. Photothermal conversion layer 4 Image recording layer 5 Image receptor HEL High density energy light A High-density energy light irradiation part B. Part not irradiated with high-density energy light C High-density energy light irradiation part 11 Thermal transfer sheet 12 Support 13 Undercoat layer 14 Photothermal conversion layer 15 Middle class 16 Image recording layer 17 Protective layer 21 Thermal transfer sheet 22 Support 23 Photothermal conversion layer 24 Image recording layer 25 Adhesive layer 26 Image receptor

Claims (3)

[Claims] 1. A thermal transfer sheet comprising a photothermal conversion layer containing a photothermal conversion substance provided on the surface of a support, and an image forming layer containing a coloring material provided on the photothermal conversion layer, is coated with high-density energy light. The bonding force between the photothermal conversion layer and the imaging layer in the high-density energy light irradiated area is reduced by imagewise irradiation, and the image receptor is then pressed onto the imaging layer via an adhesive. After that, the support and the image receptor are separated, and the image forming layer in the area not irradiated with high-density energy light is left on the photothermal conversion layer, and only the portion of the image forming layer in the area irradiated with high-density energy light is exposed to the surface of the image receptor. An image forming method characterized by forming an image on an image receptor by transfer. 2. A thermal transfer sheet comprising a photothermal conversion layer containing a photothermal conversion substance, an image forming layer containing a coloring material, an adhesive layer, and an image receptor provided in this order on the surface of a support, The bonding force between the support and the photothermal conversion layer and the bonding force between the photothermal conversion layer and the image forming layer are greater than the bonding force between the image forming layer and the image receptor, and when irradiated with high-density energy light, A thermal transfer sheet, characterized in that the bonding force between the light-to-heat conversion layer and the image forming layer is smaller than the bonding force between the image forming layer and the image receptor. 3. A thermal transfer sheet comprising a light-to-heat conversion layer containing a light-to-heat conversion substance, an image forming layer containing a coloring material, an adhesive layer, and an image receptor provided in this order on the surface of a support. By irradiating the energy light in an imagewise manner, the bonding force between the photothermal conversion layer and the image forming layer in the area irradiated with the high-density energy light is reduced, and then the support and the image receptor are separated, and the high-density energy light is applied. An image is formed on the receiver by leaving the image-forming layer in the non-irradiated areas on the photothermal conversion layer and leaving only the portions of the image-forming layer in the areas irradiated with high-density energy light bonded to the surface of the receiver. An image forming method characterized by: