JP2000255164A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method, capable of forming an image with excellent quality without securing any adhesive properties between a transferring material and an image receiving material. SOLUTION: The coloring material layer 6 side of a transferring material 10, constituted of at least a light/heat converting layer 4 and the coloring material layer 6 which are provided sequentially on the surface of a light transmitting supporting body 6 while the light/heat converting layer 4 and/or the coloring layer 6 are provided with conductivity, is opposed to and contacted with an image receiving material 12 to irradiate laser light from the side of the transferring material 10 against the image while impressing a voltage between the transferring material 10 and the image receiving material 12. Then, the image of the coloring layer 2 on the surface of the transferring material 10 is transferred to the image receiving material 12 to form the image on the surface of the image receiving material 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for forming a high-resolution image by transferring an image from a transfer material to a surface of an image receiving material using a laser beam.

[0002]

2. Description of the Related Art Conventionally, as a method of recording an image by thermal transfer, a method of directly applying pressure and heating to a thermal transfer sheet using a thermal head has been put to practical use. This method has excellent features that it can be implemented with a low noise and simple device configuration, and is maintenance-free and dry processing. In recent years, the density of the thermal head itself has been increasing, and even in this method, high resolution of an image can be achieved at a considerable level.

On the other hand, as an image recording method by thermal transfer capable of recording a higher-resolution image, a laser beam is irradiated to a transfer material, the laser beam is converted into heat in the transfer material, and the heat-sensitive recording is performed by the heat. Is known. In such a method, since the laser beam as an energy supply source can be focused to about several microns, it is possible to dramatically improve the resolution as compared with a method using a thermal head.

As a transfer material used in the laser thermal transfer recording method, a photothermal conversion layer that absorbs laser light to generate heat on a support, and a pigment is dispersed in components such as a heat-meltable wax and a binder. Hot-melt transfer sheet having the formed image forming layers in this order (JP-A-5-58045)
Is known. When using such a hot-melt transfer sheet, the heat generated in the laser light irradiation area of the light-to-heat conversion layer melts the image forming layer corresponding to that area, and is transferred onto the image receiving material stacked on the hot-melt transfer sheet. Then, a transfer image is formed on the image receiving material.

Japanese Patent Application Laid-Open No. 6-219052 discloses that a light-to-heat conversion layer containing a light-to-heat conversion substance, a very thin (0.03-0.3 μm) heat-peeling layer, and a coloring material are provided on a support. An image forming layer including the image forming layer is provided in this order, the transfer force between the image forming layer and the light-to-heat conversion layer, which are bonded by the interposition of the thermal release layer, is reduced by the transfer material using laser light irradiation. An image forming method for forming a high-definition image on an image receiving material laminated on the material is described. In this image forming method, a so-called "ablation" is used. Specifically, the thermal peeling layer partially decomposes and evaporates in a region irradiated with laser light, so that the image forming layer and the image forming layer in that region are decomposed. The bonding force with the light-to-heat conversion layer is weakened, and the image forming layer in that region is transferred onto the image receiving material laminated on the transfer material, and a transferred image is formed on the image receiving material.

An image forming method using a laser beam can use a printing paper sheet provided with an image receiving layer (adhesive layer) as an image receiving material, and can transfer a multicolor image by transferring images of different colors onto the image receiving material one after another. It has an advantage that an image can be easily obtained, and in particular, an image forming method using ablation has an advantage that a high-definition image can be easily obtained.

In these image forming methods by thermal transfer,
The adhesion between the transfer material and the image receiving material when transferring an image
Since the resolution of the image is greatly affected, the key to obtaining a high-resolution image is how to improve the adhesion between the two.

As a method for improving the adhesion between the transfer material and the image receiving material, there is disclosed a method in which a cushion layer having flexibility is provided on the transfer material and / or the image receiving material so as to absorb the unevenness of both. JP-A-5-169861).

However, when a cushion layer is provided on the image receiving material, it is difficult to use the image receiving material as a final recording medium, and it is necessary to transfer an image formed on the image receiving material to a final recording medium. There is a problem that a process is required and the process becomes complicated. Furthermore, even when a cushion layer is provided on the transfer material and the image receiving material is used as the final recording medium, the surface irregularities of the final recording medium may not be sufficiently absorbed by the cushion layer. There has been a demand for an image forming method capable of forming a high-resolution and high-quality image without securing adhesion to the image.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to form a transfer image having high resolution and good image quality and a good color tone without securing the adhesion between the transfer material and the image receiving material. It is an object of the present invention to provide an image forming method capable of performing the following.

[0011]

The above object is achieved by the present invention described below. That is, the present invention provides: <1> a transfer material in which at least a light-to-heat conversion layer and a color material layer are sequentially provided on the surface of a light-transmitting support, and the light-to-heat conversion layer and / or the color material layer have conductivity. The color material layer on the surface of the transfer material is irradiated with a laser beam imagewise from the transfer material side while applying a voltage between the transfer material and the image receiving material while bringing the color material layer side into opposing contact with the image receiving material. Is transferred imagewise to an image receiving material, and an image is formed on the surface of the image receiving material.

<2> The image forming method according to <1>, wherein the laser beam is a semiconductor laser beam. <3> The image forming method according to <1> or <2>, wherein the photothermal conversion layer formed on the surface of the transfer material has a maximum absorption wavelength of 700 to 1500 nm.

<4> Any one of <1> to <3>, wherein the light-to-heat conversion layer contains an organic dye.
The image forming method according to the item (1). <5> The image forming method according to <4>, wherein the organic dye is a cyanine dye. <6> The image forming method according to any one of <1> to <5>, wherein the colorant layer does not substantially contain the organic dye.

According to the above-described image forming method of the present invention, the laser light can be applied by utilizing the voltage applied between the transfer material and the image receiving material without securing the adhesion between the transfer material and the image receiving material. The color material layer of the transfer material is transferred imagewise by the irradiation of
An image with high resolution and good image quality can be easily formed.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the image forming method of the present invention, at least a light-to-heat conversion layer and a color material layer are sequentially provided on the surface of a light-transmitting support, and the light-to-heat conversion layer and / or the color material layer are electrically conductive. The transfer material having the property and the image receiving material are brought into contact with each other, and while applying a voltage between the transfer material and the image receiving material,
The method is characterized by irradiating a laser beam imagewise from the transfer material side, transferring the color material layer on the surface of the transfer material imagewise to the image receiving material, and forming an image on the image receiving material surface. Hereinafter, the image forming method of the present invention will be described in detail for each component.

1. Transfer material [Give conductivity to light-to-heat conversion layer and / or color material layer]
As a characteristic configuration of the present invention, conductivity is imparted to the photothermal conversion layer and / or the color material layer formed on the surface of the transfer material. Examples of the method for imparting conductivity include a method of adding a conductive substance to the light-to-heat conversion layer and / or the color material layer, and a method of providing a conductive thin film between the light-transmitting support and the light-to-heat conversion layer (the present invention). In this case, this method is also included in the concept of “conduction is imparted to the light-to-heat conversion layer”, and in this case, the conductive thin film is regarded as a part of the light-to-heat conversion layer. The specific configuration will be described later.

[Light-Transmissive Support] The material of the light-transmissive support (hereinafter sometimes simply referred to as “support”) of the transfer material is not particularly limited as long as it has light transmissivity. Various support materials can be employed according to the purpose. Preferred examples of the support material are transparent synthetic resin materials capable of transmitting laser light, and specifically, polyethylene terephthalate, polyethylene-2,6-
Examples include synthetic resin materials such as naphthalate, polycarbonate, polyethylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and styrene-acrylonitrile copolymer. Above all, biaxially stretched polyethylene terephthalate is preferable in consideration of mechanical strength and dimensional stability against heat.

The light-transmitting support of the transfer material may be subjected to a surface activation treatment and / or a single layer if necessary in order to improve the adhesion to a layer (light-heat conversion layer) provided thereon. Alternatively, two or more undercoat layers can be provided. Examples of the surface activation treatment include glow discharge treatment,
Corona discharge treatment and the like can be mentioned. The material of the undercoat layer preferably has high adhesiveness to both surfaces of the support and the light-to-heat conversion layer, low thermal conductivity, and excellent heat resistance. Examples of such a material for the undercoat layer include styrene, styrene-butadiene copolymer, and gelatin. The thickness of the entire undercoat layer is usually 0.01 to 2 μm.

[Light-to-heat conversion layer] In the transfer material of the present invention, a light-to-heat conversion layer is provided on the surface of the light-transmitting support. The light-to-heat conversion layer contains a light-to-heat conversion substance and has a function (light-to-heat conversion ability) of converting energy by laser light into heat and enabling thermal transfer of the ink layer.

(Light-to-Heat Conversion Material) The light-to-heat conversion material that can be used in the present invention is not particularly limited, and any conventionally known light-to-heat conversion material can be used. Conventionally known photothermal conversion substances are generally dyes (eg, pigments) that can absorb laser light. Examples of such dyes (eg, pigments) include organic dyes and black such as carbon black. Pigments are mentioned, and in the present invention, it is preferable to use an organic dye in view of the film strength of the light-to-heat conversion layer.

Specific examples of organic dyes include pigments of macrocyclic compounds having absorption in the visible to near-infrared region such as phthalocyanine and naphthalocyanine, and organic dyes used as laser absorbing materials for high-density laser recording such as optical disks. (Cyanine dyes other than indolenine dyes, anthraquinone dyes, azulene dyes, phthalocyanine dyes), and organometallic compound dyes such as dithiol nickel complexes. Among them, cyanine dyes are preferred in terms of light-to-heat conversion efficiency and difficulty in being destroyed by laser light. It is desired that the light-to-heat conversion material has a high light-to-heat conversion ability.
And indolenine compounds described as general formula (I) in JP-A-140924.

The amount of the light-to-heat conversion material is preferably in the range of 1:20 to 2: 1 (light-to-heat conversion material: binder) in terms of the solid content weight ratio to the binder described later, and more preferably 1:10 to 2: 1. : 1 is preferred. If the amount of the binder is too small, the cohesive force of the light-to-heat conversion layer decreases, and when the formed image is transferred to the image receiving material, the light-to-heat conversion layer is easily transferred together, causing color mixing of the image. On the other hand, if the amount of the binder is too large, the thickness of the light-to-heat conversion layer must be increased in order to achieve a desired light absorptivity, which tends to cause a decrease in sensitivity.

The thickness of the light-to-heat conversion layer (excluding the thickness of the thin film when a conductive thin film is formed) is 0.03 to 0.03.
0.8 μm, preferably 0.05 to 0.3 μm
m is more preferable. Further, the light-to-heat conversion layer has a maximum absorption wavelength (in the present invention, in the case of "the maximum absorption wavelength of the light-to-heat conversion layer", only the portion excluding the conductive thin film is a target) is in the range of 700 to 1500 nm. It is more preferably in the range of 750 to 1000 nm, and as the absorbance (optical density) at the wavelength,
It is preferably in the range of 0.1 to 1.3, and more preferably in the range of 0.2 to 1.1.

(Binder) The light-to-heat conversion layer (excluding the conductive thin film) is prepared by dispersing the above-mentioned light-to-heat conversion material and the binder in an appropriate solvent to prepare a coating solution, which is then coated on a light-transmitting support or a conductive material described later. It is formed by coating on a conductive thin film and drying. As the binder, for example, a homopolymer or copolymer of an acrylic monomer such as acrylic acid, a cellulose polymer such as cellulose acetate, polystyrene, a vinyl chloride / vinyl acetate copolymer,
Examples include vinyl polymers such as polyvinyl butyral and polyvinyl alcohol, condensation polymers such as polyester, polyamide, and polyimide, rubber thermoplastic polymers such as butadiene / styrene copolymer, polyurethane, epoxy resin, and urea / melamine resin. Can be Among these, polyvinyl alcohol, polyvinyl butyral,
Polymers such as polyester and polyimide are preferably used. Further, as a particularly preferred binder, a polyimide resin described in Japanese Patent Application No. 10-140924 can be mentioned.

(Conductive substance) When a conductive substance is added to the light-to-heat conversion layer, examples of the conductive substance include tin oxide, polyethylene glycol, carbon black, a surfactant, and an inorganic salt. 612-10033
The tin oxide fine particles doped with antimony described in Japanese Unexamined Patent Application Publication No. HEI 10-202, are preferably used.

When a conductive material is added to the light-to-heat conversion layer (excluding the conductive thin film), the conductive material has a surface resistivity of 1
The addition is preferably performed so as to be 0 ¹¹ Ω · cm or more, more preferably 10 ⁷ Ω · cm or more. For example, in the case of the above tin oxide fine particles, 50 to 500 mg / m ² , and the tin oxide fine particle / binder ratio is preferably 20/80 to 65/35 (volume ratio), more preferably 40/60 to 60/40 (volume ratio). .

(Formation of Conductive Thin Film) When a conductive thin film is provided on the surface of the light-transmitting support, the above-mentioned conductive materials can be used, and the addition amount is preferably the above value. As the binder, the binder described for the binder of the light-to-heat conversion layer is preferably used. As a method for providing the conductive layer, a method in which a coating solution in which the photothermal conversion substance and the binder are dissolved or dispersed and applied and dried is preferable. In this case, it is preferable to add a surfactant and a crosslinking agent as needed.

(Method of Forming Light-to-Heat Conversion Layer) The light-to-heat conversion layer (excluding the conductive thin film) is a coating solution in which a light-to-heat conversion material, a binder, and, if necessary, a conductive material are dissolved and dispersed as described above. Is prepared, applied on a light-transmitting support (when a conductive thin film is formed, on it), and dried to provide a support. Examples of the solvent for preparing the coating liquid include 1,4-dioxane and 1,3-dioxane.
Dioxolan, dimethyl acetate, N-methyl-2-
Examples include pyrrolidone, dimethylsulfoxide, dimethylformamide, dimethylacetamide, γ-butyrolactone, water and the like. Coating and drying can be performed by ordinary coating and drying methods.

[Color material layer] In the transfer material of the present invention,
A color material layer is provided on a light-transmitting support via a light-heat conversion layer. The coloring material layer contains a dye and an amorphous organic high molecular polymer, and further contains a conductive substance and other components as necessary.

(Dyes) Dyes are generally roughly classified into organic dyes and inorganic dyes. The former is particularly excellent in transparency of a coating film, and the latter is generally excellent in hiding. In addition, a metal powder, a fluorescent pigment, or the like may be used. Examples of dyes include azo dyes, phthalocyanine dyes, anthraquinone dyes,
Dioxazine dyes, quinacridone dyes, isoindolinone dyes, organic dyes such as nitro dyes, and inorganic dyes such as carbon black, titanium black, and titanium yellow can be used. From the viewpoint of the color tone, it is preferable that the organic dye to be added to the light-heat conversion layer is not substantially contained. In the present invention, “substantially free of an organic dye in a color material layer” means that the concentration of the organic dye at a wavelength showing an absorption peak of the transmission optical density (including the support component) of the ink layer is all. It means that it is 5% or less of the concentration. In the present invention, the coloring material layer preferably contains 30 to 70% by weight of the coloring matter, and more preferably 40 to 60% by weight.

(Amorphous Organic Polymer) The amorphous organic polymer contained in the colorant layer of the transfer material of the present invention preferably has a softening point of 40 ° C. to 150 ° C. Butyral resin, polyamide resin, polyethylene imine resin, sulfonamide resin, polyester polyol resin, petroleum resin, styrene, vinyl toluene,
α-methylstyrene, 2-methylstyrene, chlorostyrene, vinylbenzoic acid, sodium vinylbenzenesulfonate, styrene such as aminostyrene and derivatives thereof, substituted homopolymers and copolymers, methyl methacrylate,
Ethyl methacrylate, butyl methacrylate, methacrylic acid esters such as hydroxyethyl methacrylate and methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid esters and acrylic acid such as α-ethylhexyl acrylate,
Dienes such as butadiene and isoprene, acrylonitrile, vinyl ethers, maleic acid and maleic esters, maleic anhydride, cinnamic acid, vinyl chloride, vinyl acetate and other vinyl monomers alone or other monomers Can be used. These resins can be used as a mixture of two or more kinds. In the transfer material of the present invention, the color material layer is made of an amorphous organic high molecular polymer of 70%.
-30% by weight, more preferably 60% by weight.
-40% by weight.

(Other Components) According to the image forming method of the present invention, a plurality of transfer layers are used to repeatedly superpose a large number of image layers (ink layers on which images are formed) on the same image receiving material to obtain a multicolor image. When an image is formed, the colorant layer preferably contains a plasticizer in order to increase the adhesion between the images. Examples of such plasticizers include phthalates such as dibutyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl phthalate, dinonyl phthalate, dilauryl phthalate, butyllauryl phthalate, butylbenzyl phthalate, etc. Acid esters, aliphatic dibasic acid esters such as di (2-ethylhexyl) adipate and di (2-ethylhexyl) sebacate, and triesters such as tricresyl phosphate and tri (2-ethylhexyl) phosphate; Examples include polyol polyesters such as polyethylene glycol esters, and epoxy compounds such as epoxy fatty acid esters, etc. In addition to the above general plasticizers, polyethylene glycol dimethacrylate, 1,2,4-butanetriol trimethacrylate , Trimethylol ethane triacryle Also, acrylates such as pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol-polyacrylate are preferably used in combination depending on the kind of the binder used. They may be used in combination.

In general, the plasticizer in the colorant layer has a weight ratio of the total amount of the dye and the amorphous organic high molecular polymer to the plasticizer of 100: 1 to 100: 3, preferably 100: 100. : 1.5 to 100: 2. To the color material layer, in addition to the above components, a surfactant, a thickener, and the like are further added as necessary. The layer thickness (dry layer thickness) of the color material layer is preferably 0.2 to 1.5 μm, more preferably 0.3 to 1.0 μm.

When a conductive material is added to the color material layer, usable and preferred conductive materials are the same as those described in the section of the light-to-heat conversion layer.
mg / m ² , more preferably 70-300 mg / m ² ,
Conductive substance / binder ratio (volume ratio) is 20/8 to 65
/ 35, more preferably 40/60 to 60/40.

(Method for Forming Color Material Layer) The color material layer is prepared by preparing a coating solution in which a light-to-heat conversion material, a binder, and, if necessary, a conductive material and other components are dissolved and dispersed, as described above.
This can be provided by applying it to a light-to-heat conversion layer (on the case where a heat-sensitive release layer described later is formed) and drying it. The solvent for preparing the coating liquid is the same as that described in the section of the method for forming the light-to-heat conversion layer. Coating and drying
It can be carried out by using ordinary coating and drying methods.

[Thermal Separation Layer] Between the color material layer of the transfer material and the light-to-heat conversion layer in the present invention, a gas is generated by the action of heat generated by the light-to-heat conversion material of the light-to-heat conversion layer, or water is attached. Is released, whereby a heat-sensitive release layer containing a heat-sensitive material that reduces the bonding strength between the light-heat conversion layer and the colorant layer can be provided. Examples of such a heat-sensitive material include a compound (polymer or low-molecular compound) that decomposes or deteriorates by heat to generate a gas, and a compound (polymer) that absorbs or adsorbs a considerable amount of easily vaporizable gas such as moisture. Or a low molecular compound). These may be used in combination.

Examples of the polymer which decomposes or degrades by heat to generate gas include self-oxidizing polymers such as nitrocellulose, chlorinated polyolefin, chlorinated rubber, polyvinyl chloride, polyvinyl chloride, and polyvinylidene chloride. Such a halogen-containing polymer, an acrylic polymer such as polyisobutyl methacrylate in which a volatile compound such as moisture is adsorbed, a cellulose ester such as ethyl cellulose in which a volatile compound such as water is adsorbed, and a volatile compound such as water. Examples thereof include natural polymer compounds such as adsorbed gelatin. Examples of the low molecular weight compound which decomposes or degrades by heat to generate a gas include a compound which generates a gas upon exothermic decomposition such as a diazo compound or azide. It is preferable that the heat-sensitive material is decomposed or deteriorated by heat at 280 ° C. or lower, particularly at 230 ° C. or lower.

When a low molecular compound is used as the heat-sensitive material of the heat-sensitive release layer, it is desirable to combine it with a binder. As the binder, a polymer which itself decomposes or degrades by heat to generate a gas can be used, but a normal polymer having no such properties can also be used. When a heat-sensitive low-molecular compound and a binder are used in combination, the weight ratio of the former to the latter is preferably 0.02: 1 to 3: 1, and 0.02: 1 to 3: 1.
More preferably, the ratio is 5: 1 to 2: 1. The heat-sensitive peeling layer desirably covers the light-to-heat conversion layer over substantially the entire surface thereof, and the thickness thereof is generally 0.03 to 1 μm.
And preferably in the range of 0.05 to 0.5 μm.

The heat-sensitive peeling layer is decomposed and deteriorated by the heat generated by the light-to-heat conversion material of the light-to-heat conversion layer to generate a gas. Then, due to this decomposition or generation of gas, the heat-sensitive peeling layer partially disappears, or cohesive failure occurs in the heat-sensitive peeling layer, and the bonding force between the light-heat conversion layer and the coloring material layer is reduced. For this reason, depending on the behavior of the heat-sensitive release layer, a part of the heat-sensitive release layer adheres to the color material layer and appears on the surface of the finally formed image, which may cause color mixing of the image. Therefore, even when the transfer of such a heat-sensitive release layer occurs, the heat-sensitive release layer is hardly colored, that is, high in visible light, so that no visual color mixture appears in the formed image. It is desirable to show permeability. Specifically, the light absorption of the heat-sensitive peeling layer is preferably 50% or less, more preferably 10% or less with respect to visible light.

In the transfer material of the present invention, instead of providing an independent heat-sensitive release layer, a coating solution of a light-to-heat conversion layer to which the above-mentioned heat-sensitive material is added is applied to a support, and the functions of the light-to-heat conversion layer should be determined. Alternatively, a configuration may be employed in which a light-to-heat conversion layer having the function that the heat-sensitive release layer should have is formed.

[Anti-reflection layer] In the transfer material of the invention, an anti-reflection layer is preferably provided on the surface of the support opposite to the surface on which the color material layer is provided. By providing the antireflection layer, it is possible to prevent the image from being disordered and the resolution from being lowered due to irregular reflection of light during the laser light irradiation operation of irradiating the surface of the transfer material with laser light in an imagewise manner.

As a general method of forming the anti-reflection layer, materials having different refractive indices are laminated to have an anti-reflection effect on light. It is a target. Examples of materials having such an effect include sulfides such as SnS, InS, and GeS;
Oxides of n, Sn, Te, Ga, and Si are listed.

A protective cover film (eg, a polyethylene terephthalate sheet, a polyethylene sheet, etc.) may be laminated on the surface of the color material layer of the transfer material according to the present invention, if necessary, to prevent damage. Materials (especially, an image receiving sheet described later) can be laminated.

2. Image receiving material In the present invention, an image receiving material is a material in which a color material layer of a transfer material is transferred imagewise by irradiation of laser light to form an image, and in order to use the image receiving material as a final transfer medium, Any medium for obtaining an image, such as general paper and a plastic sheet, can be used as the image receiving material.
In order to obtain a higher definition and higher color image, an image receiving material having a surface treated to be suitable for receiving an image (hereinafter, such an image receiving material is referred to as an "image receiving sheet") is used. Is preferred.

The image receiving sheet is usually a sheet-like base material such as a plastic sheet, a metal sheet, a glass sheet, paper, etc. provided with one or more image receiving layers. Examples of plastic sheets include polyethylene terephthalate sheets, polycarbonate sheets,
Examples include a polyethylene sheet, a polyvinyl chloride sheet, a polyvinylidene chloride sheet, a polystyrene sheet, and a styrene-acrylonitrile sheet. Also,
Printing paper, coated paper, or the like can be used as the paper. The thickness of the base material of the image receiving sheet is usually from 10 to 400 μm, preferably from 25 to 200 μm. The surface of the base material may be subjected to a surface treatment such as a corona discharge treatment or a glow discharge treatment in order to increase the adhesion to the image receiving layer or the ink layer of the thermal transfer sheet.

In order to assist in transferring and fixing the color material layer of the transfer material on the surface of the image receiving sheet, it is preferable to provide one or more image receiving layers on the surface of the base material as described above. The image receiving layer is a layer formed mainly of an organic polymer binder. The binder is preferably a thermoplastic resin, examples of which include acrylic acid, methacrylic acid, acrylic acid esters, homopolymers of acrylic monomers such as methacrylic acid esters and copolymers thereof, methylcellulose, ethylcellulose, cellulose acetate Cellulosic polymers such as, polystyrene, polyvinylpyrrolidone, polyvinyl butyral,
Examples include homopolymers and copolymers of vinyl monomers such as polyvinyl alcohol and the like, condensation polymers such as polyester and polyamide, and rubber polymers such as butadiene-styrene copolymer. 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 strength with the ink layer. Further, it is preferable to add a plasticizer to the image receiving layer in order to adjust the glass transition temperature of the image receiving layer.

The laminate of the transfer material and the image receiving material is passed through a pressure and heat roller with the color material layer side of the transfer material and the image receiving side of the image receiving material (image receiving layer side in the case of an image receiving sheet) superimposed on each other. Can easily be obtained. The heating temperature in this case is preferably 130 ° C. or less, more preferably 100 ° C. or less.

3. Image Forming Method Next, an image forming method of the present invention using the transfer material and the image receiving material will be described. First, a material in which the surface of the transfer material on the color material layer side is in contact with or very close to the image receiving material is produced (hereinafter, the both materials are collectively referred to as an “image forming laminate”). .). Next, a voltage is applied between the transfer material and the image receiving material. Then, the surface of the image forming laminate is irradiated with laser light in an imagewise manner in a time-series manner (laser light irradiating operation), and then the image receiving material and the transfer material are separated from each other. An image receiving material to which the irradiation area has been transferred is obtained.

The image forming method of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 10 denotes a transfer material in which a light-to-heat conversion layer 4 and a color material layer 2 are sequentially laminated on a support 6, reference numeral 12 denotes an image receiving material, and the surface of the transfer material 10 on the color material layer 2 side and the image receiving material 12 In contact with, or very close to, an image forming laminate. In FIG. 1, the photothermal conversion layer 4 of the transfer material 10 is provided with conductivity.

The image receiving material 12 side of the image forming laminate is brought into close contact with the surface of a recording drum (a rotary drum having a vacuum forming mechanism therein and a large number of minute openings) by vacuuming. A predetermined voltage is applied between the transfer material 10 and the recording drum 14 by the external power supply A. At this time, the voltage is substantially applied between the light-to-heat conversion layer 4 and the color material layer 2 of the transfer material 10 and the image receiving material 12, and the Coulomb force is applied between the color material layer 2 and the image receiving material 12. Gravitational pull occurs.

The voltage applied at this time may be sufficient to assist the transfer of the color material layer by the laser light irradiation operation performed later, and the intensity of the laser light, the irradiation time, the light-to-heat conversion layer 4 of the transfer material 10 The appropriate value varies depending on the conductivity, the presence or absence of a heat-sensitive release layer, the type of the image receiving material 12, the size of both materials 10, 12 and the size of the recording drum 14, and the like. Preferably, it is about 100 V to 1000 V. The voltage to be applied may be DC or AC, and the waveform of the applied voltage may be a constant voltage, a sine wave, a rectangular wave,
Any shape such as a sawtooth wave may be used. In the present invention, in order to increase transfer efficiency, V ₁ + V ₂ × cos obtained by adding AC voltage V ₂ × cos ωt to DC voltage V _1.
It is preferably an alternating voltage of the form ωt.

In the laser light irradiation operation, scanning is performed so as to reciprocate in the width direction of the recording drum 14 from the transfer material 10 side of the image forming laminate, and the recording drum 14 is kept constant during the laser light irradiation operation. Rotate at angular velocity. Further, a configuration may be employed in which recording is performed by scanning on a plane by a laser light output head without using the recording drum 14 as described above.

Examples of the laser light include gas laser light such as argon ion laser light, helium neon laser light, helium cadmium laser light, solid laser light such as YAG laser light, semiconductor laser light, dye laser light, and excimer laser light. Direct laser light is used. Alternatively, light obtained by converting these laser lights to half the wavelength through a second harmonic element can be used. In the image forming method of the present invention, it is preferable to use a semiconductor laser in consideration of output power, ease of modulation, and the like. In the image forming method of the present invention, the laser beam has a beam diameter of 5 to 5 on the photothermal conversion layer.
Irradiation is preferably performed under the condition of 0 μm (particularly 6 to 30 μm), and the scanning speed is preferably 1 m / sec or more (particularly 3 m / sec or more).

Although the image forming method of the present invention has been described with reference to FIG. 1, the present invention is not limited to this configuration. For example, FIG. 1 shows an example in which the light-to-heat conversion layer 4 of the transfer material 10 is provided with conductivity. However, in the present invention, the color material layer may be provided with conductivity. .

The image forming method of the present invention can be used for producing a black mask or forming a monochromatic image, but can also be advantageously used for forming a multicolor image. In order to form a multicolor image by the image forming method of the present invention, for example, three or more types of transfer materials (three colors) each having a color material layer containing a colorant of a different color are manufactured independently, and an image receiving material is formed for each of them. A laser beam irradiation operation according to the digital signal based on the image by the color separation filter, followed by a peeling operation of the transfer material and the image receiving material to form a color separation image of each color on the image receiving material. Then, a method of laminating the image receiving material on an actual support such as a separately prepared printing paper or a support similar thereto is used.

[0056]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. In addition, “parts” means “parts by weight” unless otherwise specified in the text.

Example 1 1) Preparation of Coating Solution for Conductive Layer The components shown in the following coating solution composition were mixed with stirring with a stirrer, and dispersed for 1 hour with a paint shaker (manufactured by Toyo Seiki Co., Ltd.). A conductive layer coating solution was prepared.

[Coating liquid composition] Binder (Ricacoat SN-20, manufactured by Shin Nippon Rika Co., Ltd.) 200 parts N-methyl-2-pyrrolidone 2000 parts Surfactant (Megafac F-177, Dainippon Ink) 0.5 parts-Tin oxide fine particles 1 100 parts

The tin oxide 1 in the above composition was prepared by the following method. A stainless steel container comprising 80 parts of tin oxide-antimony oxide composite fine particles described in Examples of JP-A-61-20033, 160 parts of N-methyl-2-pyrrolidone, and 80 parts of zirconia beads having a diameter of 1 mm. And dispersed with paint sugar for 6 hours.

2) Formation of a conductive layer on the surface of the support On one surface of the support (thickness: 75 μm, A4 size polyethylene terephthalate film), the above-mentioned coating solution for the conductive layer was applied using a rotary coater (Whyler). After applying by drying, the applied material is dried in an oven at 100 ° C. for 2 minutes,
A conductive layer was formed. The surface resistivity measured in an atmosphere of 25 ° C. and 60% RH was 2 × 10 ⁷ Ω · cm.

1) Preparation of Coating Solution for Light-to-Heat Conversion Layer The components shown in the following coating solution composition were mixed while stirring with a stirrer, and dispersed for 1 hour with a paint shaker (manufactured by Toyo Seiki Co., Ltd.) to give a light-to-heat conversion layer. A coating solution was prepared.

[Composition of coating liquid] 10 parts of photothermal conversion substance (NK-2014, manufactured by Nippon Coloring Dyes Co., Ltd .; infrared absorbing dye) 10 parts of binder (Ricacoat SN-20, manufactured by Nippon Rika Co., Ltd.) 200 parts 2000 parts of N-methyl-2-pyrrolidone ・ 1 part of surfactant (Megafac F-177, manufactured by Dainippon Ink and Chemicals, Inc.)

4) Formation of Light-to-Heat Conversion Layer After applying the above-mentioned light-to-heat conversion layer coating solution on the conductive layer using a rotary coating machine (wheeler), the coated material was dried in an oven at 100 ° C. for 2 minutes. An intermediate layer having photothermal conversion ability was formed on the support.

The obtained photothermal conversion layer has a wavelength of 700 to 10
In the range of 00 nm, there is an absorption maximum near 830 nm,
When the absorbance (optical density: OD) was measured with a Macbeth densitometer, the OD was 1.08.

5) Preparation of Yellow Ink Layer Coating Solution Each component shown in the following pigment dispersion mother liquor composition was subjected to dispersion treatment for 2 hours using a paint shaker (manufactured by Toyo Seiki Co., Ltd.), and then the glass beads were removed. Was prepared. [Yellow pigment dispersed mother liquor composition] 12 parts by weight of a 20% by weight solution of polyvinyl butyral (Denka Butyral # 2000-L, Vicat softening point 57 ° C., manufactured by Denki Kagaku Kogyo KK) Pigment Yellow 14)) 24 parts ・ Dispersing aid (Solsperse S-20000, manufactured by ICI Corporation) 0.8 part ・ n-propyl alcohol 110 parts ・ Glass beads 100 parts

The components shown in the following coating liquid composition were mixed while stirring with a stirrer to prepare a yellow ink layer coating liquid. [Coating liquid composition]-20 parts of the above-mentioned yellow pigment-dispersed mother liquor-60 parts of n-propyl alcohol-0.05 parts of surfactant (Mega Fac F-176PF, manufactured by Dainippon Ink and Chemicals, Inc.)

6) Formation of an ink layer on the surface of the light-to-heat conversion layer On the surface of the support on which the light-to-heat conversion layer is formed, the surface of the support on which the light-to-heat conversion layer is formed is coated with the ink layer coating solution by using a wheeler. After coating for 2 minutes, the coated material was dried in an oven at 100 ° C. for 2 minutes, and a yellow ink layer (64.2% by weight of pigment, polyvinyl butyral 33.000) was formed on the intermediate layer.
7% by weight). The absorbance (optical density: OD) of the obtained ink layer was measured with a Macbeth densitometer.
D = 0.7. The thickness of the ink layer was 0.4 μm on average when measured in the same manner as in the case of the intermediate layer. Through the above steps, a thermal transfer sheet in which an intermediate layer and an ink layer were provided in this order on a support was produced.

<Preparation of Image Receiving Sheet> 1) Preparation of Coating Solution for First Image Receiving Layer The components shown in the following coating solution composition were mixed while stirring with a stirrer to prepare a coating solution for the first image receiving layer.

[Coating solution composition] 25 parts of vinyl chloride / vinyl acetate copolymer (MPR-TSL, manufactured by Nissin Chemical Co., Ltd.) 12 parts of dibutyl octyl phthalate (DOP, manufactured by Daihachi Chemical Co., Ltd.) Surfactant (Megafac F-177, manufactured by Dainippon In Chemical Co., Ltd.) 4 parts ・ Solvent (methyl ethyl ketone) 75 parts

2) Formation of the first image receiving layer on the surface of the support The above-mentioned coating solution for the first image receiving layer was coated on one surface of the support (thickness: 100 μm, A4 size polyethylene terephthalate film) using a wheeler. After coating, the coating was dried in an oven at 100 ° C. for 2 minutes to form a first image receiving layer (20 μm thick) on the support.

3) Preparation of coating solution for second image receiving layer The components shown in the following coating solution composition were mixed while stirring with a stirrer to prepare a coating solution for the second image receiving layer. [Coating liquid composition]-Polyvinyl butyral (Denka butyral # 2000-L, manufactured by Denki Kagaku Kogyo KK) 16 parts-N, N-dimethylacrylamide / butyl acrylate copolymer 4 parts-Surfactant (Megafac F- 177, Dainippon Ink and Chemicals, Inc.) 0.5 parts ・ Solvent (n-propyl alcohol) 200 parts

4) Formation of the second image receiving layer on the surface of the first image receiving layer The coating solution of the second image receiving layer is formed on the surface of the support on which the first image receiving layer is formed, on the side where the first image receiving layer is formed. Is applied using a wheeler, and the coated material is dried in an oven at 100 ° C. for 2 minutes to form a second image receiving layer (thickness 2) on the first image receiving layer.
μm). By the above steps, on the support,
An image receiving sheet in which two image receiving layers were laminated was produced.

<Image Formation> An image was formed using the image forming apparatus shown in FIG. Specifically, the image receiving sheet 1 is provided on the recording drum 14 provided with a suction hole for vacuum suction.
2 is brought into contact with the surface of the rotary drum, and the transfer material 10 obtained above is superimposed thereon and wound so that the surface on the side where the color material layer 2 is formed is in contact with the image receiving layer surface of the image receiving sheet 12. Then, the two sheets 10 and 12 were fixed to the surface of the recording drum 14 by applying a vacuum to the inside of the recording drum 14 to form an image forming laminate (in the present embodiment, the structure was used, but the image forming The laminate for the two sheets 1
0 and 12 may be superimposed).

Further, a voltage was applied between the transfer material 10 and the recording drum 14 by the external power supply A. The voltage applied at this time was an alternating current obtained by adding an alternating current of 100 V and 50 Hz to a direct current of 400 V. The recording drum 14 is rotated, and a semiconductor laser beam having a wavelength of 830 nm is condensed on the surface of the image forming laminate on the recording drum 14 from the outside so that a spot having a diameter of 7 μm is formed on the surface of the photothermal conversion layer.
While moving the recording drum 14 in the direction perpendicular to the rotation direction (main scanning direction) (sub-scanning), laser image recording was performed on the image forming laminate. Laser irradiation conditions are as follows. Laser power: 110 mW Main scanning speed: 4 m / sec Sub-scanning pitch (sub-scanning amount per rotation): 20 μm

After the laser image recording was performed, the image forming laminate was removed from the recording drum 14, and the image receiving sheet 12 and the transfer material 10 were peeled off by hand to form an image on the image receiving sheet 12. The obtained image had very good image quality.

Example 2 An example was performed in the same manner as in Example 1 except that the conductive layer was not provided and the composition of the coating solution for the photothermal conversion layer was changed as shown below. 2 was performed. [Composition of light-heat conversion layer coating solution] 10 parts of light-heat conversion substance (NK-2014, manufactured by Nippon Color Pigment Co., Ltd .; infrared absorbing dye) 200 parts of binder (Ricacoat SN-20, manufactured by Shin Nippon Rika Co., Ltd.) -N-methyl-2-pyrrolidone 2000 parts-Surfactant (Megafac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) 1 part-Tin oxide fine particles 1 120 parts

The surface resistivity of the light-to-heat conversion layer is 25 ° C. and 60% R
H was 4.2 × 10 ⁷ Ω · cm, and the same evaluation as in Example 1 was performed using the produced thermal transfer sheet.
As in Example 1, good results were obtained.

Example 3 Example 3 was carried out in the same manner as in Example 1 except that the conductive layer was not provided and the composition of the ink layer coating liquid was changed as shown below.
Was carried out. [Composition of ink layer coating liquid]-20 parts of the above-mentioned yellow pigment-dispersed mother liquor-60 parts of n-propyl alcohol-0.05 part of a surfactant (Megafac F-176PF, manufactured by Dainippon Ink and Chemicals, Inc.)- Tin oxide fine particles 1 1.5 parts The surface resistivity of the obtained thermal transfer sheet was 25 ° C. and 60% R.
H was 8 × 10 ⁷ Ω · cm, and the same evaluation as in Example 1 was performed. As a result, good results were obtained as in Example 1.

(Comparative Example) A thermal transfer sheet of Comparative Example was produced in the same manner as in Example 1 except that no conductive layer was provided. The surface low efficiency of this sample is 25 ° C
It was 9 × 10 ¹⁴ Ω · cm at 60% RH, and the same evaluation as in Example 1 was carried out. As a result, many white spots occurred in the image, and the image quality was poor.

[0080]

According to the present invention, it is possible to provide an image forming method capable of forming a high-resolution and high-quality image without securing the adhesion between the transfer material and the image receiving material.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an image forming apparatus to which an image forming method of the present invention is applied.

[Explanation of symbols]

 A: External power supply 2: Color material layer 4: Light-to-heat conversion layer 6: Support 10: Recording material 12: Image receiving material (image receiving sheet) 14: Recording drum

Claims (6)

[Claims] At least a light-to-heat conversion layer and a color material layer are sequentially provided on the surface of a light-transmissive support, and the light-to-heat conversion layer and / or the color material layer have a conductivity. And the image receiving material are brought into opposing contact, and while applying a voltage between the transfer material and the image receiving material, a laser beam is illuminated imagewise from the transfer material side to imagewise form the color material layer on the transfer material surface. An image forming method comprising transferring an image to an image receiving material to form an image on the surface of the image receiving material. 2. The image forming method according to claim 1, wherein the laser light is a semiconductor laser light. 3. The image forming method according to claim 1, wherein the light-to-heat conversion layer formed on the surface of the transfer material has a maximum absorption wavelength of 700 to 1500 nm. 4. The image forming method according to claim 1, wherein the light-to-heat conversion layer contains an organic dye. 5. The image forming method according to claim 4, wherein the organic dye is a cyanine dye. 6. The image forming method according to claim 1, wherein the colorant layer does not substantially contain the organic dye.