JP2948360B2 - Thermal transfer sheet and image forming method - Google Patents

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 of high-density energy light and a thermal transfer sheet used in the image forming method. In particular, the present invention relates to a multicolor image forming method which can be peeled and developed by laser recording and is suitable for forming a mask film and a color proof in the printing field, and a thermal transfer sheet used therefor.

[0002]

2. Description of the Related Art Conventionally, there has been known an image forming method for recording and forming an image by irradiating high-density energy light imagewise (hereinafter, referred to as a thermal image forming method).
This thermal image forming method is characterized in that an image can be recorded in a completely bright room without the need for a dark room, and processing can be performed in a dry manner without using a developer.

As a thermal image forming element used in such a thermal image forming method, for example, Japanese Patent Application Laid-Open No. 2-501552 discloses a thermal image forming element which is formed of a material which is transparent to image forming irradiation rays. A support having an imaging surface layer which can be liquefied and made flowable at a defined elevated temperature: a layer of a porous or particulate imaging substance coated on said surface layer; A layer in which the image-forming substance exhibits a cohesive strength greater than the adhesive strength between the image-forming substance and the surface layer, wherein at least one of the substances in the layer emits the radiation. Absorb,
Converting the material of the imaging surface layer into heat energy capable of liquefaction: the surface layer material, when liquefied, exhibits a capillary flow in adjacent portions of the imaging material. Thermal imaging elements are disclosed wherein the entire layer of imaging substance is substantially fixed to the support when the imaging surface layer is cooled.

That is, in the thermal image forming element disclosed in JP-A-2-501552, the image forming layer is a porous layer of a porous or particulate image forming substance. A method of forming an image using this element is to fluidize the image-forming surface layer of the portion irradiated with the above-mentioned radiation, to allow the porous layer of the image-forming substance to penetrate into the porous layer, and then to cool, Is a method of forming an image on the surface of a support by bonding the image forming layer of the portion irradiated with the above with an adhesive force stronger than the adhesive force of the image forming layer of the portion not irradiated with the irradiation light. The image on the support obtained from this thermal imaging element shows that the interface between the image forming layer and the support is relatively tightly bound by the capillary penetration described above, but the image forming layer is a porous layer. Therefore, the cohesive force (strength) is relatively small. For example, when a support on which an image is formed is used as a mask film, there is a problem that the printing life is short.

[0005]

SUMMARY OF THE INVENTION A high-sensitivity thermal transfer sheet capable of recording an image in a dry room in a completely lighted room and having a high image strength and excellent durability of an image-receiving body on which an image has been formed, and this thermal transfer An image forming method using a sheet is provided.

[0006]

According to the present invention, a light-to-heat conversion image-forming layer containing a light-absorbing substance, a binder and a photopolymerizable monomer is provided on a support surface. A heat transfer sheet provided with a heat-fusing layer containing a binder and a photopolymerizable monomer, and an image receiving body provided on the heat-fusing layer, wherein a bonding force between the heat-fusing layer and the image receiving body is supported. Greater than any of the bonding force between the body and the light-to-heat conversion image forming layer and the bonding force between the light-to-heat conversion image forming layer and the heat-fusion layer, and the bonding force between the light-to-heat conversion image formation layer and the heat-fusion layer Smaller than the bonding force with the photothermal conversion image forming layer, and
The cohesive force of the light-to-heat conversion image forming layer is larger than any of the bonding force between the light-to-heat conversion image forming layer and the heat sealing layer and the bonding force between the support and the light-to-heat conversion image forming layer. The heat transfer sheet is characterized in that, upon irradiation with light, the bonding force between the light-to-heat conversion image forming layer and the heat fusion layer becomes larger than the bonding force between the support and the light-to-heat conversion image forming layer.

The present invention also provides a photothermal conversion image forming layer containing a light absorbing substance, a binder and a photopolymerizable monomer on a surface of a support. A heat-sealing layer including a monomer is provided, and a high-density energy light is irradiated imagewise onto a thermal transfer sheet having an image receiving member provided on the heat-sealing layer, so that the photothermal The bonding force between the conversion image forming layer and the heat sealing layer is made larger than the bonding force between the support and the photothermal conversion image forming layer. By leaving the conversion image forming layer on the support and leaving only the photothermal conversion image forming layer portion of the high-density energy light irradiation region bonded to the surface of the heat-sealing layer of the image receiver, an image is formed on the image receiver. Forming There is also an image forming method characterized.

[0008] Preferred embodiments of the present invention are as follows.

(1) The thermal transfer sheet or the image forming method as described above, wherein the image receiving body is made of a material that transmits high density energy light.

(2) The thermal transfer sheet or the image forming method as described above, wherein the light absorbing substance is carbon black, an inorganic pigment, an organic pigment, a dye or the like.

(3) The binder is a polymer (for example, a cellulosic polymer such as ethyl cellulose,
Polystyrene, a vinyl polymer such as vinyl chloride-vinyl acetate copolymer, polymethyl methacrylate, an acrylic polymer such as polyacrylic acid, an ester polymer such as polyester, etc.) Image forming method.

(4) The photothermal conversion image forming layer further comprises:
The thermal transfer sheet or the image forming method described above, comprising a photoinitiator.

(5) The photothermal conversion image forming layer further comprises:
The thermal transfer sheet or the image forming method described above, comprising a coloring material.

(6) The thermal transfer sheet or the image forming method as described above, wherein the thermal fusion layer further contains a photopolymerization initiator (also referred to as a “photoinitiator” in the present specification).

(7) The weight ratio of the polymer binder and the photopolymerizable monomer in the heat sealing layer is 1: 0.1.
The thermal transfer sheet or the image forming method described above, wherein the ratio is in the range of from 1: 5 to 1: 5.

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

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

(10) The image forming method as described above, wherein the imagewise irradiation of the high-density energy light is performed from the image receiving 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 the thermal transfer sheet of the present invention.

In FIG. 1, the thermal transfer sheet 1 has a light-to-heat conversion image forming layer 3 provided on a support 2, a heat-sealing layer 4 provided thereon, and an image receiving body 5 provided thereon. It is configured.

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 substance. Examples of the material of the support 2 include, in general, high molecular compounds such as polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and styrene-acrylonitrile copolymer. Particularly, polycarbonate, polyethylene terephthalate and the like are preferable. The thickness of the support 2 is
In the case of a film, generally 10 to 400 μm, especially 50
It is preferably from 200 to 200 μm. In addition, depending on the use, a glass plate, a metal plate, or the like can be suitably used as the support 2.

The light-to-heat conversion image forming layer 3 contains a light-absorbing substance. Any light-absorbing substance can be used without particular limitation as long as it absorbs high-density energy light and generates heat. Can be.

Examples of the light absorbing substance include carbon black, graphite, inorganic pigments (for example, titanium oxide, zinc oxide, etc.), organic pigments (for example, phthalocyanine, azo, anthraquinone, etc.), organic dyes ( For example, phthalocyanine, azo, triphenylmethane, cyanine, etc.) can be mentioned.

When the thermal transfer sheet of the present invention is irradiated with high-density energy light, the light-absorbing substance absorbs the light and generates heat. Therefore, it is preferable to select a substance that efficiently absorbs high-density energy light used for forming an image using the thermal transfer sheet of the present invention as a light-absorbing substance.

Further, the above-mentioned light-absorbing substance is generally a coloring substance, and also plays a role of coloring a formed image. Therefore, it is preferable that the light absorbing substance is selected in consideration of its light absorbing property and color. For example, when an image receiving body on which an image obtained by the method of the present invention is formed is used as a mask film, the light absorbing material is preferably carbon black or graphite.

Further, the light-to-heat conversion image forming layer 3 in the present invention may further contain an appropriate coloring material. The coloring material can be arbitrarily selected from a large number of pigments, dyes, and fine metal powders in accordance with the desired image color tone without considering its light absorbing property.

Examples of the binder include cellulosic polymers such as methylcellulose, ethylcellulose and cellulose butyl acetate; and vinyl such as polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl pyrrolidone, polyvinyl alcohol and the like. Polymer, acrylic acid such as homopolymer or copolymer of acrylic monomer such as acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, styrene-maleic acid copolymer and its esterified resin Polymers, such as
Ester polymers such as polyester, gelatin, and the like can be suitably used. Particularly preferred binders include cellulosic polymers such as ethyl cellulose and methyl cellulose, and copolymers of methacrylic acid and benzyl methacrylate.

The photopolymerizable monomer is a photothermal conversion image type
It has the effect of lowering the thermal softening temperature of the layer 3 and has a high density
Thermal fusion with high heat conversion image forming layer 3 due to irradiation of energy light
The function of accelerating the thermal fusion with the layer 4, that is, increasing the sensitivity
Have. Further, the photopolymerizable monomer is polymerized by irradiating, for example, ultraviolet (UV) light to the image receiving body on which an image is formed by the method of the present invention, and becomes a polymer. It has the function of further increasing the cohesive force of a certain image and further increasing the bonding force between the photothermal conversion image forming layer and the heat sealing layer. When selecting the photopolymerizable monomer, it is preferable to consider so that one or both of the above functions can be exhibited.

The photopolymerizable monomer may be any monomer as long as it is polymerized by light (eg, high-density energy light, ultraviolet (UV) light, etc.) to become a polymer. Examples of the photopolymerizable monomer include monomers having an acryloyl group such as acrylic acid, acrylate, acrylamide, and acrylonitrile, and an epoxy group-containing monomer in which ionic polymerization is induced by Bronsted acid generated by light irradiation. Can be. Specific compounds of the photopolymerizable monomer particularly preferred in the present invention include pentaerythritol tetraacrylate, trimethylolpropane triacrylate, esters of polyhydric alcohols such as ethylene glycol dimethacrylate and acrylic acid, and various kinds of esters. A compound in which acrylate or methacrylate is added to an oligomer generated by esterification of a polyhydric alcohol and a polyhydric acid can be used.

In the photothermal conversion image forming layer 3 in the present invention, it is preferable, but not essential, that a photoinitiator be present together with the photopolymerizable monomer in order to facilitate the polymerization of the photopolymerizable monomer. The photoinitiator is not particularly limited, and any photoinitiator may be used as long as it facilitates the polymerization of the coexisting photopolymerizable monomer. Specific examples of the photoinitiator include, for example, aromatic carbonyl compounds such as 2,2-dimethoxyphenylacetophenone and benzophenone, and a system in which these compounds are combined with an amine compound and various organic dyes.

The photothermal conversion image forming layer 3 may further contain a stabilizer such as a photofading inhibitor.

A light-absorbing substance in the photothermal conversion image forming layer 3,
The ratio of the binder and the photopolymerizable monomer varies depending on the type of these substances, but the weight ratio of the total of the light absorbing substance: the binder and the photopolymerizable monomer is generally from 1: 0.5 to 1:30. In particular, the ratio is preferably from 1: 2 to 1:10. The weight ratio of binder: photopolymerizable monomer is generally from 1: 0.1 to 1: 5, in particular from 1: 0.5 to
Preferably it is 1: 2.

The photothermal conversion image forming layer 3 is formed by suspending the above-mentioned light-absorbing substance, binder, photopolymerizable monomer and the like in a suitable solvent, and placing the resulting suspension on the surface of a support. It can be formed by coating and drying. The thickness of the light-to-heat conversion image forming layer 3 varies depending on the use of the image receiver formed 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 μm. 0.0 μm is preferable.

In the heat-sealing layer 4, the light-absorbing substance of the photothermal conversion image forming layer 3 generates heat by irradiation with high-density energy light,
The heat is fused by the action of the heat to form the photothermal conversion image forming layer 3.
Has the function of increasing the bonding force between the heat-sealing layer 4 and the heat-sealing layer 4. Since the heat-sealing layer 4 and the image receiving member 5 are formed so as to be firmly bonded to each other, the photothermal conversion image forming layer 3 in the portion irradiated with the high-density energy light eventually has the image receiving member 5. It will be joined with the increased joining force. That is, in the thermal transfer sheet of the present invention, the photothermal conversion image forming layer 3
Is combined with the function of the heat-sealing layer 4, the bonding strength between the photothermal conversion image forming layer 3 and the image receiving body 5 in the portion irradiated with the high-density energy light is reduced in the portion not irradiated with the high-density energy light. It becomes larger than the binding force.

The material constituting the heat-sealing layer 4 includes cellulosic polymers such as methylcellulose, ethylcellulose and cellulose butyl acetate, polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, and vinylidene chloride. Copolymers, polyvinyl polymers such as polyvinylpyrrolidone, polyvinyl alcohol, etc., acrylic polymers such as acrylic acid, methacrylic acid, acrylic esters, methacrylic acid esters such as homopolymers or copolymers of acrylic monomers such as methacrylates, Polymers such as a styrene-maleic acid copolymer and its esterified resin, ester-based polymers such as polyester, and gelatin can be suitably used. Particularly preferred as a material constituting the heat-sealing layer are ethyl cellulose, a cellulose polymer such as methyl cellulose, a copolymer of methacrylic acid and benzyl methacrylate, a styrene-maleic acid copolymer and an esterified resin thereof. is there.

The heat-sealing layer 4 further contains a photopolymerizable monomer. Further, a photopolymerization initiator (photoinitiator) may be contained. Examples of these photopolymerized monomers and photoinitiators include the substances exemplified for the photothermal conversion image forming layer.

When the photo-polymerizable monomer is contained in the heat-sealing layer 4, the ratio between the polymer and the photo-polymerizable monomer varies depending on the type of these substances. But generally from 1: 0.1 to 1:
5, especially 1: 0.3 to 1: 2.

The image receiving member 5 is in the form of a film or a sheet, and may be made of any material as long as it transmits high-density energy light.
Examples of the material of the image receiving body 5 include those exemplified as the material of the support 2. The thickness of the image receiving body 5 is
Generally, it is preferably at least 5 μm, particularly preferably at least 25 μm. If the thickness is too small, so-called stiffness is lost, and handleability and dimensional accuracy are poor. When the thickness is large in the form of a sheet, the thickness is generally preferably 200 μm or less from the viewpoint of handleability, but the upper limit is not particularly limited.

In the thermal transfer sheet of the present invention, the bonding force between the image-receiving member and the heat-fusible layer among the bonding forces at the respective interfaces of the support, the light-to-heat conversion image forming layer, the heat-fusible layer, and the image-receiving member. Is the largest. Therefore, when manufacturing the thermal transfer sheet of the present invention, the support, the light-to-heat conversion image forming layer, the heat sealing layer, and the image receiving member may be sequentially laminated, but the bonding force between the image receiving member and the heat sealing layer is In order to obtain the largest value, the image receiving body and the heat-sealing layer are laminated in advance, and the obtained laminate (in this specification, sometimes referred to as a release sheet).
Is preferably laminated so that the heat-sealing layer contacts the photothermal conversion image forming layer formed on the support. A part of the release sheet as described above is disclosed in, for example, JP-A-61-1.
JP-A-89-535, JP-A-61-200535, and the like, and the release sheet disclosed in these publications can be used as the release sheet of the thermal transfer sheet of the present invention. Further, the release sheet of the thermal transfer sheet of the present invention can be easily manufactured by utilizing the methods disclosed in these publications.

The release sheet has the following functions: (1) a function of adhering and peeling the light-to-heat conversion image forming layer in the irradiated portion, and leaving the light-to-heat conversion image forming layer in the non-irradiated portion on the support; It has a function as a final support of the portion (image) of the photothermal conversion image forming layer, or (3) a function as a temporary support of the image.

The function (3) of the release sheet is used, for example, in a color proof creation step in printing. In general, there are two types of color proofs, an overlay type and a surprint type. In the former case, a release sheet on which images of respective colors such as cyan, magenta, yellow, and black are formed is aligned on, for example, white paper, and then overlaid and used as a color image. In the latter case, each image on the release sheet is laminated and transferred to a proof support (for example, printing paper). In the case of such an application, the adhesive force between the release sheet and the photothermal conversion image forming layer 3 needs an appropriate release property that can be transferred to the proofing support and the adhesive force between the transferred color images.

In the thermal transfer sheet of the present invention, the bonding force between the heat-sealing layer and the image receiving member is determined by the bonding force between the support and the light-heat conversion image forming layer and the bonding force between the light-heat conversion image forming layer and the heat fusion layer. The bonding force between the light-to-heat conversion image forming layer and the heat sealing layer is smaller than the bonding force between the support and the light-to-heat conversion image forming layer, and the cohesive force of the light-to-heat conversion image forming layer is light-to-heat conversion. It is larger than any of the bonding force between the image forming layer and the heat sealing layer and the bonding force between the support and the light-to-heat conversion image-forming layer. The bonding strength with the heat-sealing layer is larger than the bonding strength between the support and the photothermal conversion image forming layer.

The relationship between the bonding forces will be described with reference to FIG. 2, which schematically shows an example of a state in which an example of the thermal transfer sheet of the present invention is irradiated with high-density energy light in the image forming method of the present invention.

In FIG. 2, the bonding force F3 between the heat-sealing layer 4 and the image receiving member 5 is determined by the bonding force F1 between the support 2 and the light-to-heat conversion image forming layer 3 and the light-to-heat conversion image forming layer 3 to the heat bonding layer. 4 is larger than any of the coupling forces F2. Further, the bonding force F2 between the photothermal conversion image forming layer 3 and the heat sealing layer 4 is
Smaller than the bonding force F1 between the photothermal conversion image forming layer 3 and
In addition, the cohesive force of the light-to-heat conversion image forming layer is larger than any of the bonding force F2 between the light-to-heat conversion image forming layer 3 and the heat sealing layer 4 and the bonding force F1 between the support 2 and the light-to-heat conversion image forming layer 3. It is. Further, when the thermal transfer sheet 1 is irradiated imagewise with the high density energy light HEL from the image receiving body 5 side, the photothermal conversion image forming layer 3 in the irradiated portion of the high density energy light generates heat, and the heat causes the heat fusion layer 4 Is fused to the light-to-heat conversion image forming layer 3, the bonding force F4 between the light-to-heat conversion image forming layer 3 and the heat-fusion layer 4 is increased, and the bonding force F1 between the support 2 and the light-to-heat conversion image forming layer 3 is increased. Larger than.

When manufacturing the thermal transfer sheet 1 of the present invention,
The selection of the constituent materials of the support 2, the light-to-heat conversion image forming layer 3, the heat-sealing layer 4, and the image receiving member 5, and the selection of the preparation and lamination conditions thereof are such that the bonding force and the cohesive force satisfy the above conditions. It is necessary to do so.

Next, the image forming method of the present invention will be described with reference to FIGS.

In the image forming method of the present invention, first,
As shown in FIG. 2, high-density energy light HEL is imagewise irradiated onto the thermal transfer sheet 1 from the image receiving body 5 side.

As high-density energy light, laser light,
Xenon flash lamp light and the like can be mentioned. As a method of imagewise irradiation of the high-density energy light HEL, a method of performing irradiation by laser when using laser light and irradiating the entire surface through an image mask when using light from a xenon flash lamp is preferable. It is preferable to use a laser beam as high-density energy light because it can be directly imagewise irradiated using digital data from the image processing system. Examples of the laser include a gas laser such as an argon ion laser, a solid laser such as a YAG laser, a semiconductor laser, and a laser light obtained by converting these laser lights into a half wavelength by a second harmonic element (SHG). Etc. can be used.

When the high-density energy light HEL is irradiated from the image receiving member 5 side, the high-density energy light HEL transmitted through the image receiving member 5 and the heat sealing layer 4 enters the light-to-heat conversion image forming layer 3, and The light-absorbing substance in the irradiated portion 3A of 3 generates heat. The irradiated portion 4A of the heat-sealing layer 4 is fused with the irradiated portion 3A of the light-to-heat conversion image forming layer 3 by this heat, and the bonding force F4 between the light-to-heat conversion image forming layer 3 and the heat-sealing layer 4 is formed.
Increases, and becomes larger than the bonding force F1 between the support 2 and the photothermal conversion image forming layer 3. That is, the bonding force F2 between the light-to-heat conversion image forming layer 3 and the heat fusion layer 4 that is smaller than the bonding force F1 between the support 2 and the light-to-heat conversion image forming layer 3 increases to become the bonding force F4. This is larger than the bonding force F1 between the body 2 and the photothermal conversion image forming layer 3. The bonding strength between the photothermal conversion image forming layer 3 and the heat-sealing layer 4 in the non-irradiated portion of the high-density energy light HEL remains at F2.

In the thermal transfer sheet 1 of the present invention, the light-to-heat conversion image forming layer 3 contains the photopolymerizable monomer and
Because it contains a binder , the photopolymerizable monomer and the binder are tightly packed between the light absorbing substances,
Therefore, the photothermal conversion image forming layer 3 is not a porous layer.
Therefore, when the thermal transfer sheet of the present invention is irradiated with high-density energy light, it is unlikely that the substance of the heat-sealing layer 4 penetrates into the photothermal conversion image forming layer 3. The mechanism by which the bonding force F4 between the light-to-heat conversion image forming layer 3 and the heat fusion layer 4 by light irradiation becomes larger than F1 (of course, larger than F2) is described in JP-T-2-50155.
It is apparent that the image forming mechanism is completely different from the image forming mechanism described in Japanese Patent Application Laid-Open No. 2 (1993) -210.

Next, as shown in FIG. 3, the support 2 and the image receiving member 5 are separated from each other. As a result, the bonding force at each interface between the support, the light-to-heat conversion image forming layer, the heat sealing layer, and the image receiving member has the above-described relationship. Thus, the irradiated portion 3A of the light-to-heat conversion image forming layer 3 is bonded to the heat-sealing layer 4A, causing a shear fracture at the boundary between the irradiated portion 3A and the non-irradiated portion 3B of the light-to-heat conversion image forming layer 3, and Leave. The non-irradiated portion 3B of the photothermal conversion image forming layer 3 is separated from the heat sealing layer 4B and remains on the support 2.

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

In FIG. 2, the high-density energy light HE
Although the embodiment in which L is irradiated from the side of the image receiving body 5 has been described, the irradiation may be performed from the side of the support 2.

Since the photothermal conversion image forming layer of the present invention contains a photopolymerizable monomer and optionally a photoinitiator, the photopolymerizable monomer is irradiated with ultraviolet light to the image-receiving member on which an image is formed, for example. Can be polymerized to increase the strength of the image and impart excellent durability. Further, according to the image forming method of the present invention, an image corresponding to the non-irradiated portion of the high-density energy light is formed on the support simultaneously with the image formation on the image receiving body. By irradiating the support on which the image is formed with, for example, ultraviolet light, the photopolymerizable monomer in the image is polymerized, thereby increasing the strength of the image and imparting excellent durability.

[0055]

Next, the present invention will be described in more detail by way of examples.

Example 1 A surface of a polyethylene terephthalate film (thickness: 100 μm) was subjected to corona discharge treatment (treatment conditions: discharge in air of 3 kVA, line speed of 6).
0 m / sec) to produce a support.

On the other hand, a coating solution for a photothermal conversion image forming layer having the following composition was prepared. (Solution A) Carbon black pigment (Nihon Ciba Geigy 68 parts by weight, Microlith Black CA manufactured by K.K.) Benzyl methacrylate (BMA) / 102 parts by weight Methyl methacrylate (MMA) copolymer (BMA / MMA molar ratio = 67) / 33) Methyl cellosolve acetate 207 parts by weight Cyclohexanone 45 parts by weight (Solution B) Pentaerythritol tetraacrylate 5.5 parts by weight Photoinitiator (2,2-dimethoxyphenyl 0.3 parts by weight acetophenone, photosensitive wavelength range 430 nm or less) Activator (Sumitomo 3M Co., Ltd., 0.37 parts by weight Florado FC-430) Hydroquinone monomethyl ether 0.03 parts by weight Methoxypropyl acetate 37 parts by weight Methyl ethyl ketone 98 parts by weight 44 parts by weight of liquid A and the total amount of liquid B Under stirring Combined and,
A coating solution for a photothermal conversion image forming layer was prepared.

The above coating solution for the photothermal conversion image forming layer was applied on the corona discharge treated surface of the support at 400 rpm for 1 minute using a wheyer (rotary coating machine), and then placed in an oven at 90 ° C. for 2 minutes. After drying, the photothermal conversion image forming layer [film thickness: 1.
1 μm, optical density 2.2 (Macbeth densitometer, white light)]
Was formed. The weight ratio of carbon black (light-absorbing substance) to binder + monomer in the photothermal conversion image forming layer is as follows: carbon black: binder + monomer = 1:
5.3.

An image receiving member (release sheet) having a heat-sealing layer was prepared as follows. First, a coating liquid for a heat sealing layer having the following composition was prepared. Acrylic resin A (manufactured by Mitsubishi Rayon Co., Ltd., 228 parts by weight Dianal BR-77) Acrylic resin A (manufactured by Mitsubishi Rayon Co., Ltd., 98 parts by weight Dianal BR-64) Styrene-maleic acid resin (Nippon Shokubai) Chemical 54.5 parts by weight Oxylac SH-101 manufactured by Kogyo K.K.Pentaerythritol tetraacrylate 228 parts by weight Hydroquinone monomethyl ether 0.54 parts by weight Photoinitiator (2,2-dimethoxyphenyl 11.4 parts by weight acetophenone) (Sensitivity wavelength range: 430 nm or less) Vinyl chloride-vinyl acetate-vinyl alcohol 0.31 part by weight Copolymer (MPR-TA, manufactured by Nissin Chemical Industry Co., Ltd.) Methyl ethyl ketone 3000 parts by weight

A polyethylene terephthalate film (thickness: 100 μm) was used as an image receiving member, and the above-mentioned coating solution for a heat-sealing layer was applied on the surface of this film at 150 rpm for 2 minutes using a wooler. After drying in an oven at 100 ° C. for 2 minutes, a heat-sealing layer (film thickness: 1.1 μm) was formed to prepare a release sheet.

The support provided with the light-to-heat conversion image forming layer and the release sheet are overlapped so that the heat-fused layer of the release sheet contacts the light-to-heat conversion image formation layer. Using a laminator for color art manufactured by K.K., the two were laminated at room temperature at a speed of 90 cm / min to produce a thermal transfer sheet having a structure as shown in FIG.

A chromium photomask and a UV cut filter (which cuts light having a wavelength of 430 nm or less) are placed on the image receiving body of the thermal transfer sheet, and about 10 c
m, a light (pulse width = 3 msec) of a high-output xenon flash lamp (Type V8-2400E, manufactured by Tokyo Zenon Co., Ltd.) was applied to the image receiving surface of the thermal transfer sheet. After irradiating light with 1200 W power and cooling the thermal transfer sheet to room temperature, the support and the release sheet were peeled off. An image corresponding to the light-irradiated portion was formed on the release sheet (image receiver), and an image corresponding to the light-non-irradiated portion was formed on the support. All of the images were of high contrast (measured with a microdensitometer (white light), the optical density difference between the image area and the non-image area was 2.2), and the resolution of the image was It was 50 μm.

The image formed on the release sheet and the image formed on the support were irradiated with light from a 4 kW ultra-high pressure mercury lamp (distance between sample / lamp: 60 cm) for 2 minutes while evacuating. Even if the image after exposure was strongly rubbed with a finger, it was not damaged and showed good scratch resistance.

Example 2 A thermal transfer sheet manufactured in the same manner as in Example 1 was irradiated with a laser beam from an argon ion laser (film surface irradiation power 700 mW, beam diameter 5 μm on the film surface, scan speed 75 m / Seconds). After cooling the thermal transfer sheet to room temperature, the support and the release sheet were separated. An image corresponding to the light-irradiated portion is formed on the release sheet, and an image corresponding to the non-light-irradiated portion is formed on the support. All of the images have high contrast and excellent resolution. there were.

Example 3 A 0.5% by weight solution of chlorinated polyethylene in methyl ethyl ketone was applied on a polyethylene terephthalate film (thickness: 100 μm) using a wheyer, and dried at 100 ° C. for 2 minutes. Then, a polyethylene terephthalate support having a chlorinated polyethylene film (film thickness: 0.05 μm) was prepared.

A thermal transfer sheet was produced in the same manner as in Example 1 except that the above-mentioned support was used instead of the support subjected to the corona discharge treatment.

The image receiving body of this thermal transfer sheet was irradiated with the light of a high-power xenon flash lamp in the same manner as in Example 1, the thermal transfer sheet was cooled to room temperature, and the support and the release sheet were peeled off. Thus, a release sheet on which an image corresponding to the light-irradiated portion was formed and a support on which an image corresponding to the non-light-irradiated portion was formed were obtained. The obtained image had high contrast and excellent resolution similarly to the image obtained in Example 1.

Example 4 A thermal transfer sheet manufactured in the same manner as in Example 3 was irradiated with laser light from an argon ion laser in the same manner as in Example 2. After cooling the thermal transfer sheet to room temperature, the support and the release sheet were separated. An image corresponding to the light-irradiated portion is formed on the release sheet, and an image corresponding to the non-light-irradiated portion is formed on the support. All of the images have high contrast and excellent resolution. there were.

[0069]

The thermal transfer sheet of the present invention has a remarkable effect that an image can be dry-recorded in a completely lighted room, and the formed image has excellent resolution, high strength and excellent durability. Further, such an excellent image can be easily obtained by the image forming method of the present invention.

[Brief description of the drawings]

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

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

FIG. 3 is a cross-sectional view showing a state where a support and an image receiving member are separated from each other in the image forming method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 thermal transfer sheet 2 support 3 photothermal conversion image forming layer 4 thermal fusion layer 5 image receiver HEL high density energy light A high density energy light irradiated part B high density energy light non-irradiated part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41M 5/38-5/40

Claims (2)

(57) [Claims] On the 1. A support surface, light absorbing material, photothermal conversion image-forming layer containing a binder and a photopolymerizable monomer is provided, a binder and on the light-to-heat conversion image-forming layer
A thermal transfer sheet provided with a heat-fusible layer containing a photopolymerizable monomer, and an image receiving member provided on the heat-fusible layer,
The bond strength between the heat-sealing layer and the image receiving body is larger than any of the bond strength between the support and the light-heat conversion image-forming layer and the bond strength between the light-heat conversion image-forming layer and the heat-fusion layer. The bonding force between the layer and the heat-fusible layer is smaller than the bond force between the support and the photothermal conversion image-forming layer, and the cohesive force of the photothermal conversion image-forming layer is between the photothermal conversion image-forming layer and the heat-fusible layer. It is larger than any of the binding force and the binding force between the support and the photothermal conversion image forming layer, and further, by irradiation with high-density energy light,
A thermal transfer sheet, wherein the bonding force between the light-to-heat conversion image forming layer and the heat fusion layer is larger than the bonding force between the support and the light-to-heat conversion image forming layer. On the 2. A support surface, light absorbing material, photothermal conversion image-forming layer containing a binder and a photopolymerizable monomer is provided, a binder and on the light-to-heat conversion image-forming layer
Irradiation of high-density energy light by imagewise irradiating high-density energy light onto a thermal transfer sheet provided with a thermal fusion layer containing a photopolymerizable monomer and an image receiving body provided on the thermal fusion layer The bonding force between the light-to-heat conversion image forming layer and the heat-fusible layer in the region is larger than the bonding force between the support and the light-to-heat conversion image forming layer, and then the support and the image receiving member are separated from each other,
The photothermal conversion image-forming layer in the high-density energy non-irradiated area is left on the support, and only the photothermal conversion image-forming layer in the high-density energy light-irradiated area remains bonded to the surface of the heat-fusible layer of the image receiver. Forming an image on the image receiving body.