JPS60120352A - Image recording method - Google Patents

Abstract

PURPOSE:To enhance gradation reproducibility, etc. by using a dye or dye precursor bleachable with acrylate monomer, etc., polymerizing a photopolymerizable element by imagewise exposure, and forming a dye image with heating. CONSTITUTION:When a photopolymerizable element-contg. layer 2 is imagewise exposed, photopolymn. is caused at the exposed parts, and the monomer is polymerized to form a polymer 5. Next, when the layer 2 brought into intimate contact with a dye precursor-contg. layer 3 is heated, the nonpolymerized monomer in the unexposed parts of the layer 2 diffuses to the corresponding parts of the layer 3 and bleaches the dye in a heated state. On the contray, in the exposed parts of the layer 2, the monomer has been already used up for the polymerization, and the dye is not bleached. As a result, a dye image 6 reversed to an original image is formed in the layer 3 contg. the dye precursor.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a light and heat sensitive image recording method (photothermography), and particularly to a highly sensitive photothermography using a photopolymerization reaction.

(Prior art) Photothermography is a method that develops images by exposing a light-sensitive material to light and then uniformly heating it.It has the feature that images can be obtained only by dry processing, and it uses organic silver as a light-sensitive material. Those using salt are well known.

On the other hand, many image recording methods using photopolymerization reactions are known and have been applied to photoresists, printing plates, etc., but there are some special cases (for example, N-vinylcarbazole-carbon tetrabromide-based photosensitive materials). It is difficult to form a visible image directly by photopolymerization using a general 7-mer, except in cases where the monomer itself has a color-forming function. This is one of the reasons why polymer-based materials are difficult to apply to general photographic recording.

To visualize the image, either the exposed or unexposed areas are selectively colored with a dye solution or pigment powder depending on their permeability or viscosity, or the photosensitive layer is colored in advance. After the image is exposed to light and cured, liquid development or physical development is performed by utilizing the difference in physical properties such as the difference in solubility or the difference in adhesiveness between the cured part and the uncured part. Due to the operation, it is necessary to spatially separate the exposed portion and the unexposed portion, and the processing is complicated, and a simpler method for visualizing the image is desired.

Directly using a photopolymerizable composition (or photosensitive resin),
That is, several methods have been proposed in which a visible image is developed by a dry process using a chemical reaction inside the photosensitive material without external coloring or spatial separation of exposed and unexposed areas. Tokukai Akira! λ−r99/! describes a method of forming a visible image by heat development using a photopolymerizable composition (or a photocurable photosensitive resin) and a thermosensitive coloring material. This method uses a material in which the two components of a two-component thermosensitive coloring material are placed separately on the inside and outside of a photopolymerizable composition (or photosensitive resin), or on both sides, which is exposed to light and then heated. Then, in the areas cured by exposure, the heat-sensitive substance does not move and no color development occurs, but in the unexposed areas, the heat-sensitive substance moves, reacts, and develops color, and exhibits a positive-positive recording response.

Also, JP-A-17-/7-ri ♂3t, same j7-/ri-7jt3
1. Same evening ♂-λ302IiL and jza-, 230koj
Using a photopolymerizable composition and a heat-sensitive (pressure-sensitive) coloring material,
A method of pressure development to form a visible image is described. In both of these, one component of a two-component color-forming substance is microencapsulated together with a photopolymerizable composition, the material in which one component is placed outside the capsule is exposed to image light, and then pressure is applied. Since the hardened capsule is not destroyed, no color development occurs, but in the unexposed area, the capsule wall is destroyed by pressure and the two coloring substances come into contact.
It reacts and develops color, showing a positive-positive recording response.

These photothermosensitive and photosensitive pressure-sensitive image recording methods that use photopolymerization reactions are both based on the principle of image-wise control of the color-forming reaction through differences in mass transfer and diffusivity between the polymer and the polymer. There is.

However, the degree of curing caused by photopolymerization, that is, its property as a barrier against mass transfer, is generally not necessarily proportional to the polymerization rate; rather, when the polymerization rate reaches a certain value (gelling point), it rapidly gels and suddenly They tend to act as a barrier. Therefore, the above-mentioned image recording method has the drawback that the image density is proportional to the exposure amount, and therefore, the gradation reproducibility is poor. Nine, the polymer produced by photopolymerization is generally wood acid, which completely prevents mass transfer.
In order to provide a sufficient barrier, a very large amount of exposure must be given, and therefore, fogging is likely to occur, the signal/noise ratio (S/N ratio) is sufficiently high, and the recording sensitivity is also high. The drawback is that it is difficult.

(Objective of the Invention) The object of the present invention is basically to provide a non-silver salt image recording method that allows color image recording by dry processing, and more specifically, to provide a non-silver salt image recording method that utilizes a photopolymerization reaction. Therefore, it is an object of the present invention to provide a dry visible image forming method that has excellent gradation reproducibility and S/N ratio and is highly sensitive to light of any wavelength in the visible range.

1- (Structure of the Invention) The object of the present invention is to provide an addition-polymerizable acrylic ester monomer and/or an acrylic ester prepolymer, a photopolymerizable element consisting of a photoreducible dye, and dimedone, and the monomer and/or prepolymer. The photopolymerizable element is polymerized by imagewise exposure using a bleachable dye or a dye precursor produced under heating of a bleachable dye, followed by heating and unexposed or insufficient exposure to polymerize. The dye can be bleached by unpolymerized monomer and/or prepolymer (hereinafter monomer includes prepolymer) remaining in the exposed area, or by bleaching the dye thermally developed by the dye precursor. This was achieved using an image recording method characterized by forming an image.

The image recording method of the present invention is based on the phenomenon that a polymerizable vinyl monomer bleaches certain dyes, and when the monomer polymerizes to become a polymer, the ability to bleach the dye is lost. ＝ is based on a completely different new principle. That is, in conventional photopolymerization image recording, physical properties such as solubility in solvents, permeability or permeability of substances, tackiness, adhesion, light scattering properties, etc., are important between the monomer and the polymer produced by polymerization. Development or image visualization has been carried out by exploiting the difference between exposed and unexposed areas, spatially separating them through wet or dry processing, or optically distinguishing them by light scattering properties. The previously mentioned Unexamined Publication of Publications Showa λ-t Tata/j, 17-/7ri 134. Same J-7-/
97131. Same tf-230λμ, and same jzai, 2
．． Even in dry visible image forming methods, such as those proposed in Publications No. 3021, the principle is to control the color reaction by utilizing the difference in physical properties of monomers and polymers, that is, the difference in permeability to substances. It had been. In contrast, the image recording method of the present invention is based on the novel principle that dyes are bleached by, and only by, the monomers left after image-wise photopolymerization, even if the visible image-forming element Using a two-component heat-sensitive (pressure-sensitive) color-forming substance, the appearance of the above-mentioned JP-A-12-4 Tata1! Although similar methods and materials may appear, the present invention can be clearly distinguished from them. This is true for Tokkai Shoj'2-8'TATA! It is clear from the fact that image recording by the method described above shows a positive-positive response, whereas the method of the present invention shows a negative-positive response.

The adoption of the above-described principle of monomer dye bleaching by the present invention provides several important advantages in terms of process, application, and photographic properties in the image recording of the present invention.

A feature of the process is that it can be heated simply after image exposure.
The visible image is developed, ie the light- and heat-sensitive image recording method is achieved, and at the same time the fixing is completed. Since the remaining unpolymerized upper layer was used for dye bleaching, it no longer polymerizes even when irradiated with light, so it no longer causes fog on the white background. Furthermore, even when a material that develops color under heat, such as a two-component thermosensitive coloring material, rather than a ready-made dye is used as a visible image forming element, the white background has already been colored by heat and then bleached by the monomer. Since it is a part, it will not develop color and cause fogging even if it is heated further. That is,
In the method of the present invention, as the visible image is developed by heating, the image is simultaneously stabilized against light and heat, ie, fixed, and no additional processing for fixing is required. The superiority of this becomes clear when compared with other photothermography techniques. For example, in organic silver salt-based photothermography, the photosensitivity is generally not deactivated even after heat development, so if the image is exposed to light for a long time, white areas will fog, and if the image is exposed to room light, it will become foggy. If you accidentally heat it after exposure, a high-density fog will occur on the white background, and the image will be lost. Also,
Said Tokukai Sho! λ-rdata/! In the photothermography described in , the image is fixed against light, but it cannot be said that it is completely fixed against heat. This means that even if completely polymerized within seven months, such polymers generally have a relatively low softening point. - It is difficult to completely prevent the spread of the color-forming substance and, therefore, the formation of fog due to its reaction.

An advantage of the application is that the method of the invention can be used not only for monochromatic (eg black and white) image formation, but also for color image recording. As described in detail later, the photopolymerization reaction enables selective spectral sensitization to red, green, and blue light, and the respective photosensitive layers are coated with cyan, magenta, and yellow dyes or heated. If dye precursors that develop color are combined and laminated to form a photosensitive material, a color image can be recorded by a single color image exposure and heating.

The principle of monomer dye bleaching of the present invention also brings about the following advantages in terms of photographic properties. First, good tone reproduction is achieved. This is because the number of monomer molecules and the number of molecules of the dye bleached by them are proportional (or because they have a stoichiometric relationship). (rate) is exactly proportional to 10-. The conversion rate of monomer to polymer is generally proportional to the exposure dose, so the image density is (at least in the exposure dose range before reaching saturation density (Dmax))
It was proportional to the exposure amount, and as a result, extremely good gradation reproduction was obtained. This means that when the polymer is used as a barrier to mass transfer to control image visualization, as in known methods, the exposure and mass transfer (and thus image density)
are generally not proportional, and the amount of mass transfer tends to decrease rapidly when the exposure exceeds a certain value, so it approaches a binary (on-off) response rather than a continuous gradation, making it difficult to reproduce gradations. However, this is a major feature.

Second, an image with less fog and a high SZN ratio can be obtained. This will substantially reduce the maximum image density if the ratio of monomers and dyes (or dye precursors) present in the light-sensitive material is set to an appropriate value (for example, a slight excess of 70%). This is because it is possible to completely eliminate fog without any problems. In this regard, in image visualization methods that use polymers as barriers, unless the ratio of mass transfer rates between the polymer and the monomer is very large, there is a paradox that increasing the maximum image density will also increase fog. It is superior to

The image recording method of the present invention can take several different aspects such as how each component is arranged.

Different examples are shown in Figures 1, 3 and 3, respectively.
The present invention is not limited to these embodiments. (In each figure, only the case where a dye precursor is used as a visible image forming element is shown, which is colorless at room temperature and produces a dye by coloring after heating, and the case where a dye is used is omitted.) , a case in which the photopolymerizable element-containing layer and the dye precursor-containing layer 3 are provided on separate supports 7 to form independent sheets is shown.

When the photopolymerizable element-containing layer is imagewise exposed, photopolymerization occurs in the exposed areas, and the monomers are converted to IJ-r-j. Next, when this film is heated with the film surface in close contact with the dye precursor-containing layer 3, the dye precursor-containing layer 3 develops color on the entire surface, but the unexposed portion of the photopolymerizable element-containing layer λ is At the site opposite to the dye, the unpolymerized monomer expands under heating and bleaches the dye. On the other hand, the part opposite to the exposed part of the photopolymerizable element-containing layer λ! In this case, bleaching of the dye does not occur because the monomer has already been polymerized and consumed. As a result, a negative-positive dye image 6 with respect to the original is formed in the dye precursor-containing layer 3. The sheet after development may be peeled off, but if the support is transparent, the polymer itself is generally colorless, so it is not peeled off and the final image may be used as is. Although FIG. 1 shows an example in which the photopolymerizable element-containing layer λ is exposed from the back side of the tube support 7, it may be exposed from the front side. Also, the dye precursor-containing layer 3'I! Even if the entire surface is uniformly heated to develop color prior to i-thermal development, the result is the same.

Therefore, it is exactly the same as when a dye is used instead of the dye precursor in the dye precursor-containing layer 3, and in this case, it is not necessary to uniformly heat the layer prior to development.

FIG. 2 shows an example in which the photopolymerizable element-containing layer λ and the dye pre-cuff-containing layer 3 are laminated on one support 7 to form an integrated structure. After image exposure to this,
When thermally developed, a dye image t is formed in the dye precursor-containing layer 3 at the exposed area. Note that the stacking order of layer λ and layer 3 may be reversed to that shown in FIG. A barrier layer can also be provided between layer λ and layer 3. For example, if the component of the dye precursor acts as a polymerization inhibitor for monomers (for example, if the dye precursor is a two-component heat-sensitive coloring substance consisting of fluorans and phenols, as described later, the phenols may be polymerized). It is preferable to provide a barrier to prevent contact between this and the 7-summer. Furthermore, if a single barrier layer is provided and a dye is used instead of the dye precursor in layer 3, the wave number of the 7-mer in layer λ will change during coating or during long-term storage after coating. Prevents bleaching.

FIG. 3 shows an example in which a photopolymerizable element and a dye precursor are mixed to form a single layer and provided on a single support 7 so as to form an integral structure. In this case, one of the two elements is a continuous phase and the other is a discontinuous phase, and in FIG. 3, the photopolymerizable element is a discontinuous phase in the dye precursor-containing layer 3. Indicate the case. In this case, a barrier barrier is provided at the interface. The photopolymerizable elements contained in the barrier layer are generally prepared as microcapsules and dispersed in a continuous phase. The purpose of providing the barrier (or microcapsule wall) is the same as in the case of the laminated type described above. When thermally developed after image exposure, the 11th
A negative-positive dye image 6 is formed similarly to the example shown in FIG.

In addition, in order to form a color image, the structure shown in Figure 3 is laminated in three layers, and photopolymerization initiators sensitive to red, green, and blue, and cyan, magenta, and yellow dyes or dye precursors are placed in each layer. Then, a color image is immediately recorded by exposing the color document to light and then thermally developing it. As another method, it is also possible to record a color image using a stack of three layers having the structure shown in FIG. In this case, it is preferable to provide a barrier between each unit.

Image exposure can be performed using any light source that includes the wavelength range to which the photopolymerization initiator is sensitive. For example, a tungsten lamp, a xenon lamp, a mercury lamp, etc. are used.

Thermal development can be performed using a hot plate, a heat roller, an infrared heater, or the like. The temperature of heat development is
jOoC-, 200'C, more preferably 1000C,
/Evening O0C. The development time is 3 seconds to 120 seconds, more preferably 10 seconds to tO seconds.

Specific examples of addition-polymerizable acrylic ester monomers or acrylic ester prepolymers used in the present invention include compounds in which a portion of their acryloyl groups are replaced with methacryloyl groups, that is, mixed esters of acrylic acid and methacrylic acid. (Can be used in the present invention in the same manner as acrylic esters.) For example, monoacrylates such as methyl acrylate, ethyl acrylate, and butyl acrylate; polyethylene glycol diacrylate, polypropylene glycol diacrylate, hexanediol diacrylate, Diacrylates such as glycerin diacrylate, trimethylolpropane diacrylate, and pentaerythritol diacrylate; tri- and tetraacrylates such as trimethylolpropane triacrylate, hantaerythritol triacrylate, and pentaerythritol tetraacrylate; and polymerizable compounds added next prepolymer, for example, Tokko Shojλ-7
341, polybasic acids (e.g. phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, malonic acid, succinic acid, adipic acid, etc.) and polyhydric alcohols (e.g. evaporated ethylene glycol). , propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, trimethylolethane, trimethylolethane, pentaerythritol, etc.) are condensed, resulting in the reaction of acrylic acid with the hydroxy residue of a polyester, resulting in an oligomer, that is, l7- Examples include polyester acrylate (or oligoester acrylate), polyurethane acrylate obtained by the reaction of an acrylic ester having a hydroxyl group and isocyanate, and epoxy acrylate as described in Japanese Patent Publication No. 1701/1701. In addition, in the present invention, two or more types of monomers (including prepolymers) can also be used in combination.

Photoreducible dyes used in the present invention include methylene blue, thionine, rose bengal, erythrosin-B,
Eosin, Rhodamine, Proxin-B1 Safranin,
Acriflavin, riboflavin, fluorescein, uranine, benzoflavin, I'lJ, 'N, N'
, N'-tetra n-butylthionine, N, N, N
', N'-tetramethyl-μl-dodecyl safranin, acridine orange, acridine yellow, Ri, IO
- Carbonyl compounds such as phenanthrenequinone and penzanthrone.

The dimedone of the present invention is used as a reducing agent (or hydrogen-donating lt-compound). In the present invention, when methylene blue, methylene green, thionine, rose bengal, erythrosin-B, eoshi/, phloxine-B, +7lanin, phenosafranin, acriflavine, and acridine yellow are used as photoreducible dyes, the photosensitivity is highest. was found to be achieved. The molar ratio of the photoreducible dye and dimedone used in the photopolymerizable element varies depending on their solubility in the coating solvent, etc., but in general, the photoreducible dye 1
The amount of dimedone per mole ranges from o, oz to 3 moles, more preferably from 0.03 to 1 mole.

Dyes that can be bleached by the monomers used in the present invention, or dye precursors that produce bleachable dyes under heating, can be selected by the following simple test method.

That is, a dye or a dye precursor is dissolved or dispersed in an aqueous gelatin solution, and approximately
Coat to a dry film thickness of μm and dry. When the test sample is a dye precursor, this f/j00
Heat at c for 1 minute to develop color. The coating amount of the dye or dye precursor is adjusted so that the transmitted optical density of the dye is between /, 0-/, J'. Next, 7 drops (approximately 0./fl) of a 30 qb aqueous solution of polyethylene glycol diacrylate (number of 0CR2CH2- groups is arbitrary within λ~/j) are dropped thereon and left at room temperature for 7 minutes. If this operation υ bleaches the dye and reduces the transmitted optical density of the dropped central part to below o, i, then the dye or dye precursor
can be suitably used in the present invention. Anything exceeding o or i is generally unfavorable.

Dyes and dye precursors suitably used in the present invention
Generally, these are known two-component type color-forming substances (dye precursors) used in heat-sensitive or pressure-sensitive materials, and dyes obtained by heating them or developing color by solution reaction. A two-component color-forming substance consists of two components: a color-forming agent and a color developer.

When these two components come into contact, they generally react to form a dye even at room temperature. These two components, dispersed in a binder so as not to come into contact with each other, form the dye precursor for forming visible images of the present invention. When heated, at least one of the two components melts and diffuses, and when it comes into contact with the other component, it reacts and develops color.

Specific examples of color formers in two-component color formers are given below: US Patent λ, J Hiro, 341. , same λ, SOt, Da 72, triphenylmethane lactones (or triphenylmethane phthalide) described in JP-A-Sho JT3-RLS2211, such as crystal violet lactone, malachite green lactone; ,
Same≠tar/17ko7, sameguj-guburit, samehiroj-4!
70/, same≠6-29!110. Same reference j-≠ozi, same≠l-≠012, same≠6-U61hiro, same≠r-172j
.

171-1724. 12-1017/, zi-2
3203, Dohiro 7-22jj, 2, Tokukai Akira! λ−r,z
Fluoranes listed in 4/-3, e.g. 3
．． t-Dimethoxyfluorane, λ-methyl-6-i-propylaminofluorane, λ-guλ l-rom-3-chloro-A-n-i lovilamino-7-
Bromofluorane, 3-diethylamine-7-sibenzylaminofluorane, 3-dimethylamino-7-methylaminofluorane, ≠s's's7-titrachloro77, . 2/, 3/) Rimethyl &
'-diethylaminofluorane, 3-diethylamino-
! , t-benzfluorane, 3-diethylamine-7,
t-penzfluorane, co-N--1-F--N-phenylamino-A-diethylaminofluorane, λ-
N-phenylamino-3-methyl-6-diethylaminofluorane, no-N-phenylamino-3-methyl-7
-N-Ether-N-(P-)lyl)aminofluorane, 3-diethylamino-7-phenylfluorane, 3
'.

41-His(N-methyl-N-phenylamino)-II
, j, t, 7-titrachlorofluoran, coethoxyethylamino-3-chloro-4-diethylaminofluoran + Special Publication No. 4 #-1727, same + r-r7.2r, same + l-17JP, same ar-17JO and the same 4tl-/
172! azaphthalides and diazaphthalides, such as those described in tic-λ, such as
j-(+'-diethylaminophenyl)-J-(4<'
-dimethylamine-λ'-chlorophenyl)-7-azaphthalide, 3,3-bis(p/-dimethylaminophenyl)-≠, 7-diazaph thalide; Tokko Sho≠7-λ
ri6tko, same≠tari.

Fluoran-r-lactam (
rhodamine lactam); phenothiazines described in JP-A-KOKAI ≠ t-pr3i and JP-A 7-3114A27, such as benzoyl leucomethylene slue; JP-A JP-A Show guar ≠ t O/ 0. British patent /, /60. ? Indolyl phthalides listed in 〇; Tokko Sho J4-/
≠t73, 4'7-107113, JP-A-4' I
-91! 201c Listed spiropyrans;
Tokuko Sho≠4-/70jλ, Tokuko Shoj/-9, 2-07,
same! ≠-1ti Otsu 371C listed triphenylmethane customer patent publication show! Co/≠to Tata, Doj Hiro-/2t
Chromenoindoles described in /j/-; Furthermore, JP-A-Sho! O-/λlrij□, samejl-///jkot
1 za-ra, 23r, 13-90.2jr, 4
Aj-λri! Octopus, same j/-/21031. Same 11-/
λ103! , Tokuko Akihiro 4-/23/7, same≠&-263
0. Same jj-7≠73, same≠S-, 2J-4t! , same≠
2-λri srλ, Dohiroj-λj7144, Same≠tar19
27, etc.

Among these coloring agents, those that provide a desired coloring agent and a coloring agent having weather resistance can be selected and used in the present invention. Moreover, λ or more color formers can be used at the same time.

As a color developer for a two-component coloring substance, phenolic compounds (e.g., bisphenol A1, bisphenol B, λ
12-bis(≠-hydroxyphenyl)n-hebutane,
/, /-bis(≠-hydroxyphenyl)cyclohexane, coethyl-/.

Bisphenols such as /'-bis(Hiro-hydroxyphenyl)hexane, and t-butylphenol, ≠-
phenols such as phenylphenol), organic acids and their anhydrides and salts (e.g., salicylic acid derivatives and their zinc salts, citric acid, tartaric acid, succinic acid, maleic acid, phthalic acid, phthalic anhydride, tetrachlorophthalanhydride L I
)-)/l/ensulfonic acid and its sodium salt), inorganic salts (for example, aluminum sulfate, potassium alum, ammonium alum), acid clay, activated clay, kaolin, zeolite, and the like. Among these, bisphenols are particularly preferred in terms of color development density, speed, etc. The molar ratio of color forming agent and color developer used for forming a visible image is 0. /～! , more preferably 0.3~
The range is /.

A binder is preferably used to provide the photopolymerizable element and dye or dye precursor of the invention on a support. As a binder, water-soluble polymers such as gelatin, polyvinyl alcohol, polyvinylpyrrolidone, carboxyl methylcellulose, gum arabic, and casein, polymethyl methacrylate, polyvinyl chloride, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer, polyvinyl chloride, etc. Vinyl acetate, j-vinyl acetate-vinyl chloride copolymer, styrene and acrylonitrile copolymer, polyester, ABS resin,
Polymers soluble in organic solvents such as polyamide, chlorinated polyethylene, chlorinated polypropylene, polyvinyl butyral, polyvinyl formal, and acetyl cellulose are used. When using a dye to form a visible image according to the present invention, any of the polymers mentioned above may be used, and water or an organic solvent may be used as a solvent for coating, but dye precursors may be used. In some cases, when an organic solvent is used, the color former or developer may dissolve therein and cause immediate color development, so it is generally preferable to use a water-soluble polymer as the binder and water as the solvent for coating. In addition, depending on the method of separating the monomer and photopolymerization initiator, that is, whether they are dispersed in the binder in the form of particles or dispersed in the form of molecules, the binder and solvent should be selected appropriately after considering their solubility. You can. As the solvent other than water, acetone, toluene, methylene chloride, ethylene dichloride, chloroform λ61, methyl ethyl ketone, ethyl acetate, dimethylformamide, dimethyl sulfoxide, etc. are used.

As the support, it is preferable to use a sheet or film such as paper, polyethylene terephthalate, tri-7tyl cellulose, or waterproof paper with a layer of polymer material provided on both sides of the paper.

The material used in the image recording method of the present invention can have various compositions corresponding to the various embodiments described above (FIGS. 7 to 3).

In the embodiment shown in Figure 1, the photopolymerizable element and the visible imaging element (dye or dye precursor) are each coated separately on a support. The photopolymerizable element generally consists of a binder in addition to polymerizable monomers and photoinitiators (photoreducible dyes and dimedone). The weight ratio of monomer to binder is 0.7 to IO1, preferably 0.3 to IO1.
The range of photoreducible dyes can vary widely depending on their molecular extinction coefficient, radical generation efficiency, etc., but generally it is within the range of 0.0 r to J mol of the monomer, depending on the desired photosensitivity, etc. An appropriate selection can be made.

The monomers may be molecularly dispersed in the binder or dissolved into particles as emulsions or microcapsules. In the case of molecular dispersion, coating is performed using a solvent that dissolves both the monomer and the binder. When dispersing as an emulsion, a solvent, particularly water, which dissolves the binder but not the monomer is used, and a known surfactant is generally used to disperse and coat the emulsion in the binder solvent as an oil-in-water emulsion. When melting microcapsules, known methods such as the coacervation method described in Microcapsule J (published by Nikkan Kogyo Shimbun, Showa≠J) by Choju Kondo, coacervation method, and other methods can be used. Either 7-mer microcapsules are prepared and dispersed in a binder solution, or monomer particles are microencapsulated in a binder solution and applied. When the monomers are fractionated as emulsions or microcapsules, the photoinitiator may be included in one or both of the heptanomeric discontinuous phase or the binder monocontinuous phase. It basically depends on the solubility of the photoinitiator in the monomer and solvent. Even if the photopolymerization initiator is fractionated only in the continuous phase of the binder, as long as the ratio of the binder to the binder is within the above range, the two radicals generated in the continuous phase will enter the monomer particles. is formed and photopolymerization occurs.

On the other hand, visible imaging elements, in addition to dyes or dye precursors, are generally applied dispersed in a binder solution. The overlapping ratio of the coloring agent of the dye or dye precurner to the binder is in the range of 0/ to 0, more preferably /, /0. In the case of dyes, they may generally be dispersed in molecules or particles in a binder, but in the case of dye precursors, a color former and a color developer are generally used to prevent color development before image formation. As particles, they are dispersed in a solvent (binder solution) in which they are insoluble.

Further, as a visible image forming element, a known or commercially available thermosensitive coloring paper can be used as it is, or after being heated to uniformly develop a color, it can be used in the image formation of the present invention. The pH in the photopolymerizable element and the visible imaging element is from 12 to 12, more preferably from 3 to IO
It is desirable to adjust within the range of . This is because bleaching of dyes by monomers during image formation is difficult to occur at low pH, and occurs too much at high pH. The film thickness of each element is 065 to 30 μm1, preferably 7 to 1 μm.
It is 0 μm.

In the embodiment shown in FIG. 2, the same photopolymerizable element and visible imaging element described above are then coated in layers on the same support. When a barrier layer is provided, the polymer mentioned above is used as a binder, but it is necessary to select the polymer and solvent so that the binder is completely or almost insoluble in the liquid to be coated on the barrier layer. be. Particularly when the upper layer coating solution consists of a water-soluble binder and water, a water-insoluble polymer is used for the barrier layer. The thickness of the barrier layer can be determined by trial to avoid deterioration of photopolymerizability, but it is generally in the range of 0.1 to 10 μm.

30- In both the double-headed cases shown in FIGS. 1 and 2, it is necessary to appropriately determine the quantitative ratio of monomer and dye or dye precursor. If the monomer is in excess, bleaching will occur too much and the image density will decrease, and if the dye (dye precursor) is in excess, the bleaching will not be sufficient and capri will occur.

The molar ratio of the monomer and the dye (color former or dye precursor) is θ, /~/, 0. Preferably 0.
, t, is suitable in the range of 1.0. This can be set by adjusting the quantitative ratio of the 7-mer, dye, etc. in the photopolymerizable element and the visible image forming element, or by adjusting the film thickness of each layer.

In the embodiment of FIG. 3, the monomer is then generally entrained in a binder with the visible imaging element in microencapsulated form. Preferably, the same polymer as the barrier described above is used as the wall material of the microcapsule. The quantitative ratio of each component, etc. are the same as in the embodiments of FIGS. 1 and 2. The thickness of the layer provided on the support is 0.2 to 30 μm
, preferably in the range of 7 to 70 μm.

This will be specifically explained using examples.

Examples 1-10 To a homogeneous solution consisting of
Add 3 g of the mixture and perform ultrasonic emulsification in the dark for 1 hour to remove the monomers (and ethylene dichloride and dimedone).
An emulsion was prepared in which a photoreducible dye and polyvinyl alcohol were dissolved in an aqueous solution. This is coated with polyethylene terephthalate film (thick/
00 μm) and dried to produce a photosensitive material. The thickness of the photopolymerizable layer was approximately jβm.

Preparation of thermosensitive coloring material: Disperse with glass beads for 1 hour using a homogenizer.
c (This is called dispersion A) Next, -33- was similarly dispersed (this is called dispersion B) Dispersion A
sy and the dispersion liquid Bioy were uniformly mixed and coated on a polyethylene terephthalate film (thickness 10 mm) using a bar coater.
0 μm) and dried to produce a two-component heat-sensitive coloring material. The thickness of the heat-sensitive layer was approximately j μm.

A black and white step wedge (the step difference is Log [
Transmission density] of 0.3) and filters of the colors listed in Table 7 were stacked, and a halogen lamp was passed through the filters.
It was exposed for 30 seconds at 10,000 lux.

Next, this was coated with a thermosensitive coloring material and heated uniformly for 30 seconds on a hot plate heated to 1.20'C.
A black image with good gradation reproducibility was developed. This is because the thermosensitive coloring material reacts with heat to produce a black dye, but the monomer remaining in the unexposed areas of the photosensitive material diffuses and bleaches this coloration, forming an image. The amount of bleaching -3μ- is proportional to the amount of residual turmeric and therefore the image density is proportional to the rate of polymerization. Image sensitivity (number of steps) and maximum image transmission (IkW (Dmax)) are shown in Table 1.

The minimum transmission density (Dmin) f″i was all about 067. Filters of colors other than those listed in the table (
For example, in Example 1, no or almost no image was obtained when a green or blue filter was used. Furthermore, all the photosensitive materials not containing dimedone gave no image 1#. (In other words, photopolymerization does not occur,
The dyes generated from the heat-sensitive material were bleached all over. )Also,
The obtained image was uniformly exposed for 5 minutes at 10,000 lux, but no change was observed, indicating that it had already been fixed.
- Example 11 This example is based on Example 1 (methylene blue/dimedone system)
The relationship between the pH of the photosensitive layer and the photosensitivity is shown in FIG. To adjust the pH, add citric acid-N a 2 H to the coating solution for the photosensitive layer.
A buffer substance of P.04 was added, and the pH was measured by dropping one drop of water (approximately O0λcc) onto the photosensitive layer and using a microprobe pH meter. pH value is 3°λ, 3. jt, g, θ,
Hiro, tlg, O and? .

When a type B photosensitive material with a pH value of 3.0 was prepared and image formation was performed in exactly the same manner as in Example 1, the pH value was 3. A good image was obtained at λ~Hiroshi and t, but it was hardly seen at θ and ? , O, no images were obtained at all. The pH value is μ,
O and 4Z, 4 have the highest sensitivity and large Dmax, and photosensitive materials without added buffer substances (those of Example 1, p
The H value μ, j) was exactly the same. As described above, photoheavy dust content shows a maximum at a pH value of about μ to j, which is because the rate of photopolymerization of acrylamide by the methylene blue/dimedone system shows a maximum at a pH value of 4-f (see the above-mentioned document J
, Phya, Chem, &ri, 21317 (1ri a, t
).

Example 12 (Comparative example) In this example, when β-diketones having a similar chemical structure to dimedone were used as the hydrogen-donating compound instead of dimedone, no polymerization occurred when the monomer was an acrylic ester; We show that dimedone is a very unique compound for the photopolymerization of acrylic esters. In Examples 3 and 4, acetylacetone, 7,3-indanedione, or diethyl malonate was used as a hydrogen-donating compound in place of dimedone at 0.0% or less, respectively. /3f using
Examples 3 and 4 were carried out in the same manner as above, but in both cases, no photopolymerization occurred and no image was produced. In addition, in the case of acetylacetone, p)l
l'iii gu, 11 ta, o, io.

This experiment was carried out on photosensitive materials of O, but none of them were photopolymerized.

(p)1(2) Adjustment and measurement were performed in the same manner as in Example 11. ) According to the above-mentioned literature (described in Example 11), acrylamide is photopolymerized by methylene blue/acetylacetone and thionine/acetylacetone, but in contrast, the activity of the polymerization initiator is completely different depending on the monomer. It is shown that.

Examples 13 to s9 1 Comparative Example) This example shows the results when a compound reported to be used for photopolymerization of acrylic esters was used as a hydrogen donating compound.

Example 2 was carried out in exactly the same manner as in Example 2, except that the compounds listed in Table 2 were used as the photoreducible color chart and the hydrogen donating compound, and the results shown in Table 1 were obtained. All of them were inferior in sensitivity to the light-sensitive material using dimedone of the present invention, and were highly opaque due to the black dye.Example 2: An integrated image recording material was prepared as follows. A thermosensitive coloring material was produced in exactly the same manner as in Example 1. A 10 ql methylene chloride solution of polymethyl methacrylate (average molecular weight approximately 50,000) was applied onto this heat-sensitive layer and dried to form a barrier layer having a thickness of j .mu.m. Furthermore, the same photopolymerizable layer as used in the photosensitive material of Example 1 was applied thereon to the same thickness and dried. This was exposed through a step wedge and a red filter in exactly the same manner as in Example 1, and then heated in an oven for 30 seconds, and a negative-positive 7-stage black image was observed.Dmax was /, j, D
min is 0. /, the gradation reproduction spanned j stages.

[Brief explanation of the drawing]

11λ and 3 respectively show different embodiments of the solder forming method of the present invention. In each figure, (A) is before exposure;
(B) shows the state after exposure, (] shows the state after heat development. In each figure, l is the recording material, c is the photopolymerizable element-specific layer, λ'
3 is a photopolymerizable element-containing material, 3 is a dye precursor-containing layer,
Buddha is a barrier! indicates a polymer produced by photopolymerization, t indicates a dye image, and 7 indicates a support. Patent applicant Fuji Photo Film Co., Ltd. 11!1 (A) (B) Figure B) @3rzr B) (C) (C) (C) Procedural amendment Dear Commissioner of the Japan Patent Office 1, Indication of the case Showa! Patent application No. 2212, No. 2°
Invention 0 Title Image recording method 3, Relationship with the case of the person making the amendment Patent applicant Location 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name (52)
0) Fuji Photo Film Co., Ltd. 4. Subject of the amendment The description in the "Detailed Description of the Invention" column 5 of the description and the "Detailed Description of the Invention" section of the description of the amendment will be amended as follows. 1) It is 1 from "This is" on page 37, line 17 to the 3rd spring/line. ' Delete up to '. 2) Delete the lines from "I mentioned above" on page 31/line I to "I show" on page 32, line 3. Procedural Amendment Document Showa J 2015 λ 27th April 1, Incident Display Showa O 2017 Patent Application No. 2.2r-! No. 21 No. 2, Title of the invention Image recording method 3, Relationship with the case of the person making the amendment Patent applicant Location 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name (52)
0) Fuji Photo Film Co., Ltd. 4. Subject of amendment The description in column 5 of "Detailed explanation of the invention" of the specification and the description of section 1 "Detailed explanation of the invention" of the description of the amendment are amended as follows. (1) Correct "photoreducible dye" on the first page to line io to read "dimedone". (2) Correct “Dimedon” in line 10 of the first page to “photoreducible dye.” Procedural amendment 1. Display of incident Showa SR year patent application No. λ-21221 No. 2
, Title of the invention Image recording method 3, Relationship with the case of the person making the amendment Patent applicant Address 210-4 Nakanuma, Minamiashigara City, Kanagawa Prefecture Subject of the amendment ``Detailed Description of the Invention'' column of the specification & Contents of the amendment The statement in the "Detailed Description of the Invention" section of the specification is amended as follows. (1) After "consisting of." on page 27/line A, [the amount of monomer applied is Q, 3~J o t /m'', more preferably /-tof/m2, and the amount of binder applied is is o, t-2of/WL21 preferably 0.,
t-10t/WL2. ” is inserted. (2) From "dye or" on the 10th line of the λth page to "range" on the 1th line [Dye 17t is a dye precursor, and the coating amount of the spontaneous coloring agent is 0. λ~-〇t/m, preferably o, r-
tf/m”, and the amount of binder applied is 0.0λ~-
f/7-WL2, preferably 0. /~/1/1n2. The amount of binder per it of dye or color patch precursor is 0.07 to 1 it, more preferably 0. /-/l range. ” he corrected. (3) Correct "00lN1.0" in the first line of page 31 to "01INIO". −λ−

Claims (1)

[Claims] Heating a photopolymerizable element consisting of an addition-polymerizable acrylic ester monomer and/or an acrylic ester prepolymer, a photoreducible dye, and dimedone, and a dye that can be bleached or a dye that can be bleached by the monomer and/or prepolymer. The photopolymerizable element is polymerized by imagewise exposure using the dye precursor formed below and then heated to remove any remaining unexposed or exposed areas with an insufficient exposure to polymerize. 1. An image recording method comprising forming a dye image by bleaching a dye with an unpolymerized monomer and/or prepolymer, or by bleaching a dye thermally developed by a dye precursor.