JPH021884A - Transferred image forming method - Google Patents

Abstract

PURPOSE:To obtain transferred images of a high density repeatedly with good reproducibility at the same density without scumming by incorporating at least one kind of specific compds. into the photopolymn. initiator used in a a photopolymerizable compsn.-contg. layer. CONSTITUTION:An image forming material is formed by forming the conductive compsn.-contg. layer 2 on a a conductive base consisting of a conductive layer 1A and a base 1B. The electric resistance of the layer 2 is increased by subjecting said layer to imagewise exposing and an electrostatic charge is formed in the exposed region 2A by a corona charger 3 to form an electrostatic latent image 3A. The image is developed by a toner and is transferred. At least one kind of the compds. expressed by the separate formula are incorporated into the photopolymn. initiator used for the layer 2. In the formula, X is a hydrogen atom, alkyl group, aryl group; Y is a fluorine atom, chlorine atom, bromine atom; (n) is 1-2 integer; (a) is 1-2 integer; (l) is 0 or 1. The layer 2 contains the photopolymn. initiator expressed by the separate formula, the photopolymerizable or photocrosslinkable compds. having the ethyleneic unsatd. bond, and a sensitizer, etc., at need.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a transferred image, and more particularly, to a method for forming a transferred image suitable for creating a color proof using a photopolymer method.

[Background of the Invention] When printing a large number of sheets by creating a printing plate using a plate-making material such as a PS plate from a color original, the color original is usually converted into a four-color halftone negative (or halftone positive) using a color scanner or the like. )
After creating the image, we go through processes such as pasting, reversing, and retouching, then create a four-color one-sheet positive, make one proof, check the finished product, and then proceed to final printing. In this case 1. ir
q In the production process of negatives or halftone positives, checking of scanner disassembly, in the production process of single-sheet positives, checking of pasting, etc., in the production process of proof printing, checking of the person who ordered the printing, etc. Color proofs are created and checked for this purpose. As the photosensitive material 11 for producing color proofs, there are known photosensitive materials using silver halide photography, electrophotographic photosensitive materials, and photosensitive materials using photopolymers, and toner pigments, dyes, etc. are used as color images. Depending on the purpose of use, negative-positive method,
There are both positive and positive methods.

The present invention is a so-called zero printing method in which a photosensitive material using a photopolymer (photopolymerizable polymer) is imagewise exposed, corona charged, toner developed, and the toner image is transferred to a transfer material to form an image. It is a technology that belongs to

Conventionally, a method of forming a toner image using a photopolymer on a photosensitive material by the zero printing method was disclosed in Japanese Patent Application Laid-Open No. 62-2.
No. 95081, and the publication also discloses that this method can be used for small-scale printing, creating color proofs, etc.

Issues that E'AIrA attempts to solve] However,
In the conventional method described above, because the difference in electrical resistance between the exposed and unexposed areas is insufficient, a high-density transferred image cannot be obtained under conditions that do not cause background smudges, but on the other hand, a high-temperature transferred image cannot be obtained. It was found that there is a drawback that dirt easily appears. It has also been found that there is a drawback that it is difficult to repeatedly obtain transferred images of the same density with good reproduction.

Therefore, there was a problem in that the performance was insufficient for use as a color proof.

Therefore, the present invention provides a method for forming a transferred image that can obtain a high-density transferred image without background smudge, can repeatedly obtain transferred images of the same density with good reproducibility, and can be suitably used as a color proof. The task is to do so.

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the present inventors have found that 2-o-substituted hexaarylbiimidazole and 2-o-il-substituted hexaphenyl bimidazole are used as photopolymerization initiators. It has been discovered that when imidazole is used, the difference in electrical resistance between exposed and unexposed areas is insufficient, and that the above problem can be solved by using a photopolymerization initiator unique to the present invention. This is the heading that led to the completion of the present invention.

That is, the method for forming a transferred image according to the present invention is as follows.

An imaging element having a photopolymerizable composition-containing layer on a conductive support is imagewise exposed to increase the electrical resistivity of the exposed areas of the photopolymerizable composition-containing layer and then corona charged. A method of forming a transferred image by forming a electrostatic latent image on the exposed area, first developing with a toner, and then transferring the toner image to a transfer material, the photopolymerizable composition containing the photopolymerizable composition. The photopolymerization initiator used in the layer contains at least one compound represented by the following general formula (r).
．． 1.

General formula (I) [wherein, X represents a hydrogen atom, an alkyl group or an aryl group, Y represents a fluorine atom, a chlorine atom or a bromine atom, and n
represents an integer of 1 to 3, m represents an integer of 1 to 2, and 1 sentence represents O or 1. "[Action J] In the present invention, by using the photopolymerization initiator of the above general formula (1), the exposed (polymerized) region has a large electrical resistance, maintains a sufficiently high initial charge, and The attenuation rate of the charge is extremely low, while the charge in the unexposed area is
Since the attenuation to substantially zero is fast, the above-mentioned problem can be achieved, and at the same time, the unique effects of the present invention are exhibited.

[Specific Structure] The structure of the image forming material of the present invention is such that a layer containing a photopolymerizable composition is provided on a conductive support. First, the structure of each of these layers will be clarified.

Photopolymerizable composition-containing layer of the present invention! The composition of the still life-containing layer includes a photopolymerization initiator represented by the above general formula CI), a photopolymerizable or photocrosslinkable compound having an ethylenic undisturbed bond, a binder, and, if necessary, a sensitizer, etc. include.

In the above general formula (I), X is a hydrogen atom having 1 to 6 carbon atoms.
Among the alkyl or aryl groups, particularly preferred alkyl groups are methyl and propyl groups, and examples of the aryl group include phenyl.

JP-A-54-74728 and JP-A-55-77742
In the publication, 2-hecomethyl-5-vinyl-1
, 3,4-oxadiazole compounds, and 2-triheromethyl-5-7ly-1,3,4-oxadiazole compounds, but compounds containing phenolic OH groups have better solubility. ing.

Compounds containing this phenolic OH group are disclosed in, for example, JP-A-55-24113, U.S. Pat.
The following general formula (I
It is synthesized by dealkylating (or dealkylenating) the ether bond moiety of the compound I) or (m).

General formula (n) General formula (III) In the above formula, X, V, the letters 1m and n have the same meanings as in general formula (I). R represents a lower alkyl group or a benzyl group.

The dealkylation (or dealkylenation) reaction of the ether bond moiety of the compounds of general formulas (II) and (III) is as follows:
For example, Organic 5 syntheses, C
o11ectvolua+eV, 412-414
(1973), H. Gerecke et al., He1vetica Chimica Acta, 5.
9.2551-2557 (1978), by E. H. Vickery et al., Journal
ofChemistry, 44.4444-444
B (1979) Method, or M, NodeP+, Journal of Chemistry, 45.
4275-427? (1980) method, etc.

Specific examples of the photopolymerization initiator represented by general formula CI) used in the present invention are shown below.

Organic described in Organic described in Salmon Jo 1” Irimachisuji Week N.

O Margin below O N.

・1 No.

N00 NOl NO ! ■ NO 1O NO No.

N.

Synthesis examples of some of the above-mentioned exemplified compounds are shown below.

Synthesis Example 1 2-Trichloromethyl-5-(p-hydroxystyryl)-1,3,4-oxadiazole (Exemplary Compound No.
Synthesis of l) 17.8g of p-methoxycinnamic acid and 13.9H of p-
Ditrophenol with 50m thionyl chloride and 50II
The mixture was refluxed for 1 hour in 1 liter of benzene. After distilling off thionyl chloride and benzene, the solid obtained was washed with water and then dried. A substantially theoretical amount of p-methoxycinnamic acid p-nitrophenyl ester was obtained.

p-Methoxy azoic acid p'-nitrophenyl ester 18
．． 0g was added to a solution of 11.4g of 80% hydrazine hydrate and 75ml of methanol, and heated under reflux for 30 minutes.After allowing the reaction solution to cool, 8.3g of triethylamine was added, and 40ml of water was added.
0ml was added. 7.8 g of p-methoxycinnamic acid hydrazide was precipitated as colorless crystals.

19.2 g of p-methoxycinnamic acid hydrazide, 29.2 g of hexachloroacetone and 100 mJL of acetonitrile
When the reaction mixture was heated under reflux for 20 minutes and cooled, colorless crystals of N-p-methoxycinnamoyl-N'-
30.1 g of trichloroacetyl hydrazide was precipitated.

After heating and refluxing 4 g of N-p-methoxycinnamoyl-N'-)lichloroacetyl hydrazide and phosphorus oxychloride (Jan) for 3 hours, it was divided into 200 g of ice water, and the resulting precipitate was recrystallized from methanol to obtain 2-trichloro Methyl 5-(
2.5 g of p-methoxystyryl-1,3,4-oxadiazole was obtained.

Add 18 g of anhydrous aluminum chloride to 20 ml of methylene chloride, and dissolve 14 g of 2-trichloromethyl-5-(p-methoxystyryl)-1,3,4-oxadiazole in 80 ml of methylene chloride while stirring at room temperature. After the solution was added dropwise, one reaction was continued by stirring at room temperature for 7 minutes.

After washing the reaction solution with water-cooled water, methylene chloride was distilled off under reduced pressure. The remaining solid after distillation was dissolved in ethyl acetate, n
- Recrystallized from hexane mixed solvent, 9.6 g of 2-trichloromethyl-5-(p-hydroxystyryl)-1,3,4-oxadiazole (melting point 179-180°C)
I got it.

Synthesis Example 2 Synthesis of 2-trichloromethyl-5-(3',4'-dihydroxystyryl)-1,3,4-oxadiazole (Exemplary Compound No. 5) 3.4-Methylenedioxycinnamic acid 28. 7g of p-nitrophenol and 19.3g of p-nitrophenol were added to 60rml of toluene, and 33.1g of thionyl chloride was added dropwise thereto, followed by heating for 2 hours; After distilling off excess thionyl chloride and toluene, 3.4-methylenedioxycinnamic acid 4'-ditrophenyl ester 42. I got it.

3.31.3 g of 4-methylenedioxycinnamic acid 4'-nitrophenyl ester and 18.8 g of 80% hydrazine hydrate
g was added to 125 mJ1 of methyl alcohol, and the mixture was heated under reflux for 1 hour. The cooled reaction solution was poured into 700 ml of water, and the resulting precipitate was carefully separated to obtain 3,4-methylenedioxycinnamic acid hydrazide! 9.7. I got it.

3.4-methylenedioxycinnamic acid hydrazide 17.5g
1 part acetonitrile to 28.3 g hexachloroacetone
N-(3,4-methylenedioxycinnamoyl)-N'-trichloroacetylhydrazide 28 was obtained by adding 00al and cooling the 0 reaction solution, which was heated under reflux for 30 minutes.
．． 2g was obtained.

N-(3,4-methylenedioxycinnamoyl)-
-trichloroacetylhydrazide 20.0. 150 mJL of phosphorus oxychloride was added to the solution, and after heating under reflux for 3 hours, the reaction solution was poured into ice water.
'-methylenedioxystyryl)-1,3,4-oxadiazole lft, Ig was obtained.

11 g of anhydrous aluminum chloride in 20 mJ1 methylene chloride
was added, 50JL of ethanedithiol was added while cooling on ice, and to this was added 2-trichloromethyl-5-(3').

The reaction solution to which 6.7 g of 1,3,4-oxadiazole (4'-methylenedioxystyryl)-1,3,4-oxadiazole was added was returned to room temperature, and the reaction was continued for a further 3 hours.The reaction solution was washed with water-cooled water. After that, methylene chloride was distilled off under reduced pressure, and the residue was recrystallized from a mixed solvent of ethyl acetate and n-hexane to give 2-trichloromethyl-5-(3'',4'-dihydroxystyryl)-1. , 3.7 g of 3,4-oxadiazole (melting point 183-185°C) was obtained.

Synthesis Example 3 2-chloromethyl-5-(p-hydroxystyryl)-
1,3,4-oxadiazole (Exemplary compound No. 7)
1.9 g of the intermediate p-methoxycinnamic acid hydrazide obtained in Synthesis Example 1 was mixed with 1.7 g of monochloroacetic anhydride and acetic acid +5
The mixture was stirred at room temperature for 30 minutes in a mixture of n+1. The resulting precipitate was recrystallized from a mixed solvent of methanol and water to obtain 0.8 g of N-p-methoxycinnamoyl, N'-chloroacetyl hydrazide.

0.8 g of N-p-methoxycinnamoyl-N'-chloroacetyl hydrazide and 1 liter of oxychloride 9710111
Time addition f! + After refluxing, the reaction solution was divided into ice water, and the resulting precipitate was recrystallized from ethanol to give 2-chloromethyl-5-
(p-methoxystyryl)-1,3,4-oxadiazole was obtained.

Add tog of anhydrous boron tribromide to 20+JL of methylene chloride, cool to -20°C, and while stirring, chloride 5g of 2-chloromethyl-5-(p-methoxystyryl)-1,3,4-oxadiazole. A solution dissolved in 40 ml of methylene was added dropwise to the solution, and the reaction was continued at -20°C for 2 hours and at room temperature for 3 hours. After washing with cooled water,
Methylene chloride was distilled off under reduced pressure, and the residue was recrystallized from a mixed solvent of ethyl acetate and n-hexane to give 2-chloromethyl-5-(p-hydroxystyryl)-1,3,4-
3.5 g of oxadiazole (melting point 174-175°C) was obtained.

Synthesis Example 4 Synthesis of 2-trichloromethyl-5-(3',4'-dihydroxyphenyl)-1,3,4-oxadiazole (exemplified compound NO, 15) 9.8 g of methyl 3.4-dimethoxybenzoate (0,0
5 mol) and 15 ml of 85% hydrazine hydrate were refluxed for 2.5 hours with stirring. The reaction solution was cooled, and the resulting crystals were filtered and washed with water to obtain 3,4-dimethoxybenzoic acid hydrazide. The yield was quantitative.

3,4-dimethoxybenzoic acid hydrazide 3 obtained above
．． 9 g (0.02 mol) of trichloroacetic anhydride8.
2 g (0.02 mol) under stirring, and after stirring for 30 minutes, 15 g (1) of phosphorus oxychloride,
1 mol) was added thereto, and the mixture was exchanged with stirring for 3 hours. After cooling the reaction solution, it was poured into crushed ice aoog. The resulting precipitate was washed with water, dried, and then recrystallized from ethyl acetate.
5.0 g of -trichloromethyl-5-(3',4'-dimethoxyphenyl-1,3,4-year-old xadiazole) was obtained.

Add 10 g of anhydrous boron tribromide vinegar and 50 g of ethanethiol to 20 mft of methylene chloride, and cool to -20°C. 4-oxadiazole 5gtl-
After dropping a solution dissolved in 20 mM methylene chloride, the reaction was continued at -20°C for 2 hours and at room temperature for 3 hours. After washing with water-cooled water, methylene chloride was distilled off under reduced pressure, and the residue was recrystallized from ethyl acetate.
Trichloromethyl-5-(3',4'-dihydroxyphenyl)-1,3,4-oxadiazole (melting point 192
~194°C) 3.1 g was obtained.

Synthesis Example 5 2-Trichloromethyl-5-(p-hydroxyphenyl)-1,3,4-oxadiazole (exemplary compound NO,
Synthesis of 11) The above compound was obtained by the same method as in Synthesis Example 4 using methyl p-methoxybenzoate as a raw material.

Melting point 147-149°C.

Synthesis Example 6 2-Tribromomethyl-5-(p-hydroxystyryl)-1,3,4-oxadiazole (exemplary compound NO,
Synthesis of 8) After dissolving 8.73 g of the intermediate p-methoxycinnamic acid hydrazide obtained in Synthesis Example 1 in 180+1 dioxane, 8.2 g of tribromoacetic acid bromide was added dropwise over 10 minutes with stirring. After stirring this reaction solution at room temperature for 4 hours, the resulting precipitate was separated. After adding 200+ JL of water to liquid No. 11, the mixture was cooled to obtain 8.8 g of crystals of N-P-methoxycinnamoyl-N'-)ribromoacetyl hydrazide.

After heating and refluxing 3.9 g of this crystal and 20 ml of phosphorus oxychloride for 1 hour, the reaction solution was poured into ice water, and the resulting precipitate S was recrystallized from ethyl acetate.
2.0 g of p-methoxystyryl-1,3,4-year-old xadiazole was obtained.

Anhydrous aluminum chloride 2.0 in methylene chloride 20mJ1
While stirring at room temperature, a solution of 1.5 g of 2-tribromomethyl-5-(p-methoxystyryl)-1,3,4-oxadiazole dissolved in 2 h of methylene chloride was added. After the dropwise addition, the mixture was further stirred at room temperature for 7 hours, and the reaction continued. After pouring the reaction solution into ice water, washing with water was repeated. Methylene chloride was distilled off under 0 g pressure, and the resulting solid was dissolved from ethyl acetate. Recrystallization yielded 1.1 g of 2-tribromomethyl-5-(p-hydroxystyryl)-1,3,4-oxazole (melting point 179-181°C).

A photopolymerizable or photocrosslinkable compound that accommodates ethylenically unsaturated bonds (hereinafter referred to as the monomer of the present invention as necessary) is a compound having at least one ethylenically unsaturated bond in its chemical structure, It has chemical forms such as monomers, prepolymers, dimers, trimers and other oligomers, mixtures thereof, and copolymers thereof. Examples thereof include unsaturated carboxylic acids and others, esters with aliphatic polyhydric alcohol compounds, amides with aliphatic polyhydric amine compounds, and the like.

Specific examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, incrotonic acid,
These include maleic acid.

Salts of unsaturated carboxylic acids include sodium salts and potassium salts of the aforementioned acids.

Specific examples of esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids include acrylic esters such as ethylene glycol diacrylate, triethylene glycol triacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, and propylene. Glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate.

Pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, sorbitol triacrylate, sorbitol triacrylate, unrubitol pentaacrylate, sorbitol hexaacrylate, polyester acrylate oligo There are boos etc.

Examples of methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, pentaerythritol dimethacrylate, and pentaerythritol dimethacrylate. Erythritol trimethacrylate, dipentaerythritol dimethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis-[p-(3-methacryloxy-2hydroxypropoxy)phenyl]dimethylethane, bis=[p-
(acryloxyethoxy)phenyl]dimethylmethane, etc.

As the itaconic acid ester, ethylene glycol shitaconate, propylene glycol shitaconate, 1
．． 3-butanediol shiitaconate, 1,4-butanediol shiitaconate, tetramethylene glycol shiitaconate, pentaerythritol shiitaconate,
Examples include sorbitol tetrataconate.

Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetracrotonate.

Examples of incrotonic acid esters include ethylene glycol diincrotonate, pentaerythritol diincrotonate, and sorbitol tetraincrotonate.

Examples of maleic esters include ethylene glycol simarate, triethylene glycol simarate, pentaerythritol simarate, and sorbitol tetramaleate.

Mention may also be made of mixtures of the aforementioned esters.

Specific examples of amides of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylenebis-acrylamide, methylenebis-methacrylamide, l,6=hexamethylenebis-acrylamide, and 1,6-hexamethylenebis-methacrylamide. amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide, etc.

Other examples include polyisocyanate compounds having two or more incyanate groups in one molecule, as described in Japanese Patent Publication No. 48-41708.

Examples include vinyl urethane compounds containing two or more polymerizable vinyl groups in one molecule to which a vinyl heptamine containing a hydroxyl group represented by the following general formula is added.

GHz-C(R)COOCHzCH(R')OH (wherein R and R' represent a hydrogen atom or a methyl group) The hexamer of the present invention is the main charge carrier in the photosensitive system. The monomer must have sufficient charged surface so that the charge in the unexposed areas decays to zero or almost zero within about 15 seconds after charging, while the small exposed areas in the highlighted areas To facilitate toning of the halftone dots (dat+), i.e. to avoid too rapid loss of charge from small isolated exposed halftone dots surrounded by large unexposed areas; It is preferred that the unexposed areas receive some initial charge and hold it for a few seconds, so it is considered preferable to use a 7-pin resistor with a resistance in the range of about 10@5 to 10@9 ohms.

As a binder, chlorinated polyethylene, chlorinated polypropylene, polyacrylic acid alkyl ester (alkyl groups include methyl group, ethyl group, n-butyl group,
jsa-butyl group, n-hexyl group, 2-ethylhexyl group, etc.), acrylic acid alkyl ester (alkyl group is the same as above) and 7-crylonitrile, If! Copolymers with at least one monomer such as vinyl chloride, vinylidene chloride, styrene, butadiene, polyvinyl chloride, copolymers of vinyl chloride and 7-crylonitrile, polyvinylidene chloride, copolymers of vinylidene chloride and 7-crylonitrile polymer,
Polyvinyl acetate, polyvinyl alcohol, polyacrylonitrile, copolymer of acrylonitrile and styrene,
Copolymer of acrylonitrile, butadiene and styrene, polymethacrylic acid alkyl ester (the alkyl group is a methyl group).

Ethyl group, n-propylno^, n-butyl group, 1so-
butyl group, n-hexyl group, cyclohexyl group, 2-ethylhexyl group, etc.), methacrylic acid alkyl ester (the alkyl group is the same as above), and at least one monomer such as 7-acrylonitrile, vinyl inide, vinylidene chloride, styrene, butadiene, etc. copolymer with polystyrene,
Poly-α-methylstyrene, polyamide (8-nylon, 6.6-nylon, etc.), methylcellulose, ethylcellulose, acetylcellulose, polyvinyl formal, polyvinyl butyral, etc. can be used.

As the sensitizer used as necessary, any sensitizer that increases the photopolymerization rate when used in combination with the photopolymerization initiator represented by general formula (1) can be used without any restriction.

In addition to the above, the photopolymerizable composition-containing layer of the present invention may contain a polymerization initiator other than the present invention, a polymerization inhibitor, a UV absorber,
Additives such as plasticizers, dyes or pigments may be included.

The composition ratio of the photopolymerizable composition-containing layer of the present invention is 1:100 parts by weight of the photopolymerizable composition of the present invention to 0.0 parts by weight of the photopolymerization initiator.
01 to 50 parts by weight is preferable, more preferably 0.1 to 50 parts by weight.
The binder is preferably O to 1000 parts, more preferably O to 500 parts, and the sensitizer is preferably 0 to 100 parts by weight, more preferably 0.
~20 parts by weight.

The conductive support of the present invention may be (1) entirely conductive, or (2) may have a conductive layer on the side in contact with the photopolymerizable Nl acid-containing layer. The conductive support may be a support having a non-layered conductive portion formed on the side in contact with the photopolymerizable composition-containing layer. The layer and conductive portion are grounded in any manner.

(2) As the conductive support, fully bending sheet) (manufactured by A Bun or C
A conductive paper, a conductive polymer film, etc. are used, and the support having the conductive layer (2) is made of, for example, aluminum-deposited polyethylene terephthalate, and the conductive part (2) is formed. As a support,
For example, a material in which A powder or Cu powder is fixed to the surface of a film or paper by an appropriate means is used.

Preparation of image-forming material To prepare the image-forming material used in the present invention, a thermophotopolymerizable composition is mixed with ethylene dichloride, cyclohexanone, methyl ethyl ketone, methyl serrone, ethyl seron lube, methyl seron lube acetate, monochlorobenzene, and toluene. , xylene, ethyl acetate, butyl acetate, etc., and mix with one or more solvents such as xylene, ethyl acetate, butyl acetate, etc., and use a normal coater such as a reverse roll coater, air knife coater, Meyer bar coater, etc., or spin coating such as a T-Kaho error. It can be obtained by coating and drying using a device.

The thickness of the photopolymerizable composition-containing layer is preferably 1 to 11001 L, more preferably 2 to 1 OJL11.

FIG. 1 shows an example of the image forming material used in the present invention. It is a material-containing layer.

Image forming method (1) The image forming material obtained above is set in a predetermined position and exposed imagewise as shown in FIG.

After creating a mesh negative of usually four colors from the original using a color scanner or the like, the mesh negative is inserted between an exposure source and an image forming material and exposed.

The exposure source may be a metal halide lamp, a chemical lamp, or the like, but the exposure source is sufficient to cause substantial polymerization in the exposed areas and to maintain resistance between the exposed and unexposed areas. It has to be something that makes a difference.

In the present invention, as shown in FIG. 2, the potential difference between the exposed area 2A and the unexposed area 2B is preferably 150 to 200 volts, more preferably 150 volts. The potential difference here is electrostatic paper analyzer 5P manufactured by Kawaguchi Electric Co., Ltd.
Measured at -428.

(2) Next, corona charging is performed as shown in FIG. 3 to form an electrostatic latent image 3A in the exposed area. The charging electrode used in the corona charger 3 is preferably a corotron, but may also be a scorotron.

In the present invention, since a specific photopolymerization initiator was used,
The exposed region has a characteristic that it has a large electrical resistance and retains a sufficiently high initial charge, and the rate of decay of that charge is not only extremely low, but also that the charge in the unexposed region decays quickly to become substantially zero.

For this reason, a portion with residual charges is formed in the exposed area 2A by the corona bomber 3, and the charges in the unexposed area 2B flow out to the outside via the ground.

An electrostatic latent image 3A is formed by the residual charge.

(3) Next, toner development is performed (see FIG. 4).

The toner 4 is preferably charged to a charge opposite to the above-mentioned charge. This is because toner development can be easily performed by Coulomb force.

In order to obtain particularly good image resolution, liquid development is preferred.

A liquid developer is a colloidal suspension of polymeric toner particles in a volatile, insulating carrier liquid. A primary example of a carrier liquid is an isoparaffinic liquid sold under the tradename Isopar G. The fine toner particles usually consist of a binder resin, such as a styrene-acrylic copolymer or polyester, and a pigment. The developer solution may contain an ionic charge agent or stabilizer, which helps maintain a quiet charge on the toner particles.The developer solution disperses the wax to give the toner self-fixing properties. A description of a developer of this type which may be used in particular in carrying out the process of the invention is found in European Patent Application No. 098,084 (11384/1).
(published on the 11th of May).

In the present invention, to obtain a color image, development is repeated using four types of toner: Y (yellow) toner, M (magenta) toner, C (cyan) toner, and Bk (black) toner. good.

(4) Next, the above toner image is transferred to a transfer material 5 (for example, paper, film, etc.) as shown in FIG. A transferred image (positive) is thus obtained.

[Effects of the Invention] According to the present invention, it is possible to obtain a high-density transferred image without background smudge, and it is also possible to obtain a transferred image of the same density with good reproducibility, and the transfer can be used as a color proof. A method of forming an image can be provided.

[Example] Examples will be given below, but the present invention is not limited thereto.

Apply a photopolymerizable coating solution with the following composition to a thickness of 100 g ff.
1 of aluminum vapor-deposited polyethylene terephthalate film to a thickness of 5 doses, and on top of this coating film a thickness of 20
GM polypropylene cover sheet was laminated.

Styrene-methyl methacrylate (molar ratio 70:30) copolymer 5.0 g Pentaerythritol tetraacrylate 3.6 g Photoinitiator X.

Chain transfer agent or sensitizer: 1g methyl ethyl ketone 20g methylcellosolve acetate) 20g This film was overlaid with a negative mask and exposed to 50% with a 3kw metal halide lamp.
After imagewise exposure from a distance of c+s, the cover sheet was removed from the film and an electrostatic latent image was formed by corona charging.

The potentials of the exposed and unexposed areas were measured using an Electrostatic Paper Analyzer 5P-428 manufactured by Kawaguchi Machinery Co., Ltd.
I added 11.

The initial voltage VO is measured within 1 second after charging and 1
(V15...V2O) at 15 second intervals until the minute, then 2 minutes IG (V120) i:fl16 constant.

The % attenuation in the exposed area is +00 (1-V120/V15) It was calculated as

The results are shown in Table 1.

Margin below Images were evaluated according to the following procedure.

A film (master) having a photopolymerizable layer containing the above photopolymerization initiator to form and develop a latent image.
After imagewise exposure, the sample was mounted on a test apparatus in which two gear-driven aluminum drums were separated by a gap of 3-5 mils.

The lower drum contains a corona discharge electrode and a toner processing device, and by rotating this drum counterclockwise, the master is first charged, then developed, and finally the image is transferred onto the paper. Ru.

Charging was performed by corona discharge at 10 ElkV for 10 seconds.

(After completion of the +F charge, the Hs image is developed by rotating the lower drum so as to pass through the toner processing position.

The development was carried out by liquid development using MRP toner manufactured by Ricoh Co., Ltd. using isoparaffinic solvent Isopar G as a carrier shell.

Next, the transfer was performed using a bias roll method. A high voltage of opposite polarity to the toner particles is applied to the upper drum.

This voltage creates an electric field that moves the toner particles on the master onto the paper wrapped around the upper drum. The distance between the master and transfer drum is 0.08~0.13m+* (3~5
transfer is purely electrostatic.

Using this method, the image reproducibility of a film (master) having a photopolymerization layer containing the photopolymerization initiator described above was evaluated. The evaluation was performed on the first image, the 10th image, and the 20th image.

The results are shown in Table 2.

In addition, rOJ means good transferred image, "Δ" means solid density increase,
Partial background staining, "x" indicates increased solid density, considerable background staining, respectively.

The photopolymerization initiator of the present invention has a large potential difference between exposed and unexposed areas, and has an extremely low charge decay rate in exposed areas.
It was possible to obtain a high-density transferred image without background stains. It was also revealed that the reproducibility of the transferred image was good.

[Brief explanation of the drawing]

1 to 5 are schematic cross-sectional views showing an example of the image forming method of the present invention. 1: Conductive support 1A: Conductive layer 1B: Support 2: Photopolymerizable composition-containing layer 2A: Exposed area 2B: Unexposed area 3: Corona charger 3A: Charged charge 4: Toner 5: Transferred material

Claims (1)

[Scope of Claims] An image-forming material having a photopolymerizable composition-containing layer on a conductive support is imagewise exposed, and the electrical resistance of the exposed area of the photopolymerizable composition-containing layer is changed. A method of forming a transferred image by increasing and then corona charging to form an electrostatic latent image in the exposed area, then developing with a toner, and then transferring the toner image to a transferred material. A method for forming a transferred image, wherein the photopolymerization initiator used in the photopolymerizable composition-containing layer contains at least one compound represented by the following general formula (I). General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, X represents a hydrogen atom, an alkyl group, or an aryl group, Y represents a fluorine atom, a chlorine atom, or a bromine atom, and n
represents an integer of 1 to 3, m represents an integer of 1 to 2, and l represents 0 or 1. ]