JPH021883A - 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 a photopolymerizable compsn.-contg. layer. CONSTITUTION:An image forming material is formed of a conductive base consisting of a conductive layer 1A and a base 1B and the conductive compsn.- contg. layer 2 thereon. 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, Z denotes a nonmetallic atom group necessary for forming a heterocyclic nucleus contg. nitrogen and R is an aryl group, heterocycle. The layer 2 contains the photopolymn. initiator expressed by the separate formula, the photopolymerizable or photocrosslinkable compds. having the ethylenic 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 creating a printing plate using a plate-making material such as a PS plate from a color original and printing a large number of sheets, the color original is usually printed using a color scanner or the like to create a 4-color mesh negative (or i+1
After creating a 1-sheet positive, we go through processes such as pasting, turning, lettering, and checking, then create a 4-color 1-sheet positive, make a proof, check the finish, and then proceed to final printing. In this case, check for scanner disassembly during the process of creating a net negative or net positive.

Chairing functions such as checking pasting etc. in the production process of a single sheet positive, and confirmation of the print orderer in the proof printing process are necessary for a good print finish, and color proofs are created for this purpose. Checks are being carried out. The photosensitive materials used to create this color proof include silver salt photosensitive materials and electrophotographic photosensitive materials.

Photosensitive materials using photopolymers are known1.
Some use toner pigments, dyes, etc. as color images, and there are both negative-positive and positive-positive systems depending on the purpose of use.

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 light-sensitive material by the zero printing method was disclosed in Japanese Patent Application Laid-Open No. 82-2.
No. 95081, and the publication also discloses that this method can be used for small-scale printing, creating color proofs, etc.

[9. Problems to be solved by Ming] However, in the conventional method described above, the difference in electrical resistance between the exposed area and the unexposed area is insufficient, so a high-density transferred image cannot be obtained under conditions that do not cause background smudges. On the other hand, it was found that under the conditions for obtaining a high-density transferred image, background stains tend to appear. 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 2-〇-substituted hexaarylbiimidazole and 2-o-substituted hexaphenyl biimidazole 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. Heading 6, which led to the completion of the present invention
That is, the method for forming a transferred image according to the present invention involves imagewise exposing an image forming material having a photopolymerizable composition-containing layer on a conductive support, and exposing the exposed photopolymerizable composition-containing layer to light. Transfer by increasing the electrical resistivity of the area and then corona charging to form an electrostatic latent image on the exposed area, first developing with toner, and then transferring the toner image to the transferred material. The method for forming an image is characterized in that 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) [In the formula, Z represents a nonmetallic atom group necessary to form a nitrogen-containing heterocyclic nucleus, and R is a substituted or unsubstituted 7-aryl group, or a substituted or unsubstituted heterocyclic nucleus. [Representing a ring. However, the decay 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 The composition of the photopolymerizable composition-containing layer of the present invention is expressed by the above general formula (
It contains a photopolymerization initiator represented by I), a photopolymerizable or photocrosslinkable compound having an ethylenically unsaturated bond, a binder, and, if necessary, a sensitizer.

In the photopolymerization initiator represented by the above general formula (I), Z
It is a group of nonmetallic atoms necessary to form a nitrogen-containing heterogeneous nucleus. Examples of the nitrogen-containing heterocyclic nucleus formed with Z include thiazoles such as benzothiazole, α-naphthothiazole, and β-naphthothiazole;
Oxazoles such as benzoxazole and β-naphthoxazole, selenazoles such as benzoselenazole,
Imidazoles such as imidazole and benzimidazole; isoindoles such as 3,3-dimethylindolenine; quinolines such as quinoline and inquinoline; 1,3.
4-Oxadiazole! , 3.4-thiadiazole, 1,3.4-selenadiazole and other diazoles, 1
, 2.4-triazole and other triazoles, as well as pyridine, chimexaline, and S-triazine.

Examples include phenanthridine and the like. These Z
The nitrogen-containing heterocyclic nucleus that is formed with the above may have a substituent, and examples of the substituent include a methyl group and an ethyldi group. (
Alkyl groups having 1 to 6 carbon atoms such as, methoxy groups, alkoxy groups having 1 to 6 carbon atoms such as ethoxy groups, 11! Carbohydrates having an alkyl group of 1 to 4 carbon atoms such as an amino group substituted with a halogen atom such as chlorine or bromine, an alkyl group of 1 to 4 carbon atoms such as a cyano group, an amino group, or a dimethylamino group, or a carbomethoxy group. Number of carbons such as alkoxyphenyl group, p-chlorophenyl group s ~ 10
and a substituted or unsubstituted 7-aryl group.

When R is an aryl group, it represents monocyclic and polycyclic compounds having 6 to 14 carbon atoms such as phenyl and naphthyl. In the case of substituted aryl groups, substituents include alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, and 6 to 1 carbon atoms.
Examples include aryl groups up to 0, amine groups substituted with alkyl groups having 1 to 6 carbon atoms, and halogen atoms such as fluorine, chlorine, and bromine. Furthermore, the alkyl group used as the above-mentioned substituent has 1 to 1 carbon atoms, such as methoxy and ethoxy.
2 may have an alkoxy group or a halogen atom such as chlorine as a substituent.

Preferred substituents for these substituted aryl groups include alkyl groups having 1 to 4 carbon atoms such as methyl group and ethyl group, alkoxy groups having 1 to 4 carbon atoms such as methoxy group and ethoxy group, dimethylamine 7 groups, Examples include amine groups substituted with alkyl groups having 1 to 4 carbon atoms such as diethylamino groups, and halogen atoms such as fluorine, chlorine, and bromine.

When R is a substituted or unsubstituted heterocycle, the peterocycle is a monocyclic or polycyclic compound containing at least one atom of nitrogen, oxygen, or sulfur, preferably furan, virol, pyridine, etc. It is a 5 or 6Q ring heteroaromatic compound.

In the case of a substituted heterocycle, the same substituents as those used for the above-mentioned substituted aryl group can be mentioned.

Among the compounds represented by the general formula (I) used in the present invention, compounds represented by the following general formula (II) are more preferred.

General Formula (II) II In the above formula (II), Z' represents a group of nonmetallic atoms necessary to form a nitrogen-containing heterocyclic nucleus with X. X represents 0, S, or N-R', where R' represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a substituted alkyl group, a 7-aryl group having 6 to 10 carbon atoms, or a substituted aryl group. R represents the same meaning as R in general formula CI).

Typical examples of the compound represented by the general formula (II) include thiazoles, oxazoles, imidazoles, oxadiazoles, and triazoles.

The photopolymerization initiator represented by the general formula CI) used in the present invention can be synthesized using a known method.

As one of the representative synthesis methods, for example, T, Caro
nna et al. Journal of Chemical
5ociet7PerkinII J No. 2035-2
038 pages (1972) and rJournal of
Chemical 5ociety (C:) J No. 17
Examples include a method of synthesis from compounds represented by the general formula (m) and the general formula (IV), as described in 1, pp. 47-1750 (1971).

General formula (I11) General formula (IV) ) from e.g. sulfuryl chloride, also by E. Muller et al.
iga Annalen der ChemieJ No. 7
It can be synthesized using an oxidizing agent such as selenium dioxide as described in Vol. 13, pp. 87-95 (1988).

General formula (V) (Here, Z and R have the same meanings as in the case of general formula (I).) Specific examples of the photopolymerization initiator represented by general formula CI) used in the present invention are shown below. .

Below are the photopolymerization initiators exemplified in the margin NOI NO7 NOl 2 C1]3 OCI+3 NO o 4 NO, lO No, 14 rθ No, 15 NO, 16 No, 17 Photopolymerizable or photocrosslinkable compounds having ethylenically unsaturated bonds ( The monomer of the present invention (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, and includes monomers, prepolymers, dimers, 39-mers, and other oligomers. They have chemical forms such as 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,
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 tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, polyester There are acrylate oligomers, 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, nrubitol tetramethacrylate, bis-[p-(3-methacryloxy-2-hydro),
xypropoxy)phenyl]dimethylethane, bis-[
Examples include p-(acryloxyethoxy)phenyl]dimethylmethane.

As the itaconic acid ester, ethylene glycol shitaconate, propylene glycol shitaconate, 1
．． 3-butanediol diitaconate), 1,4-butanediol shiitaconate, tetramethylene glycol shiitaconate, pentaerythritol shiitaconate,
Examples include nlubitol 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 diisocrotonate, pentaerythritol diincrotonate, and sorbitol tetraincrotonate.

Examples of maleic esters include ethylene glycol simalate, triethylene glycol simalate, pentaerythritol dimaleate), sorbitol tetramaleate, and the like.

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 methylene bis-acrylamide, methylene bis-methacrylamide, and! , 6-hexamethylenebis-acrylamide, 1,6-hexamethylenebis-methacrylamide, diethylenetriamine trisacrylamide, xylylenebisacrylamide, xylylenebismethacrylamide, and the like.

As another example, a vinyl monomer containing a hydroxyl group represented by the following general formula is added to a polyincyanate compound having two or more incyanate groups in one molecule, which is described in Japanese Patent Publication No. 48-41708. Examples include vinyl urethane compounds containing two or more polymerizable vinyl groups in one molecule.

OH2<(R)COOCH;+CH(R')OH (wherein R and R' represent a hydrogen atom or a methyl group) The monomer of the present invention is the main charge carrier in the photosensitive system. The monomer must have a sufficient degree of charge such that the charge in the unexposed areas decays to zero or nearly zero within about 15 seconds after charging, while the small exposed areas in the highlighted areas . To facilitate toning of the dots, i.e. to avoid too rapid loss of charge from small isolated exposed 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 u,
+SQ-butyl group, n-hexyl group, 2-ethylhexyl group, etc.), acrylic acid alkyl ester (the alkyl group is the same as above) and at least one of the seven polymers such as acrylonitrile, vinyl chloride, vinylidene chloride, styrene, butadiene, etc. Polymer, polyvinyl chloride, vinyl chloride and 7
Copolymer with crylonitrile, polyvinylidene chloride, copolymer with vinylidene chloride and 7-crylonitrile, polyvinyl acetate, polyvinyl alcohol.

Polyacrylonitrile, copolymer of acrylonitrile and styrene, copolymer of acrylonitrile with butadiene and styrene, polymethacrylic acid alkyl ester (alkyl groups include methyl group, ethyl group, n-propyl group, n-butyl group) , 1so-butyl group, n-hemoyl group, cyclohexyl group, 2-ethylhexyl group, etc.)
, methacrylic acid alkyl ester (alkyl group is same as above) and acrylonitrile, vinyl chloride, vinylidene chloride,
Copolymers with at least one monomer such as styrene and butadiene, polystyrene, poly-α-methylstyrene, polyamides (6-nylon, 6.6-nylon'5
), methylcellulose, ethylcellulose, acetylcellulose, polyvinyl formal, polyvinyl butyral, etc. can be used.

As the sensitizer used if necessary, a sensitizer that increases the photopolymerization rate when used in combination with the photopolymerization initiator represented by general formula (I) is selected. Specific examples of such sensitizers include benzoin, benzoin methyl ether, benzoin ethyl ether, 2,2-dimethoxy-2-phenylacetophenone, 9-fluorenone, 2-chloro-8-fluorenone, 2-methyl-9 -2 luorenone,
8-Anthrone 2-bromo-3-anthrone, 2-ethyl-8-anthrone, 8. lO-anthraquinone, 2-
Ethyl-9,10-anthraquinone, 2-t-butyl-
9,IO-anthraquinone, 2,8-dichloro-8,l
O-anthraquinone, xanthone, 2-methylxanthone, 2-methoxyxanthone, thioxanthone, benzyl, dibenzalacetone, p-(dimethylamino)phenylstyryl ketone, p-(dimethylamino)phenyl p-methylstyryl ketone, benzophenone, p-(
Examples include dimethylamino)benzophenone (or Michler's ketone), p-(diethylamino)pentsuphenone, and benzanthrone. Among these compounds, it is particularly preferable to use Michler's ketone.

Furthermore, preferred sensitizers in the present invention include compounds represented by the following general formula described in Japanese Patent Publication No. 51-48516.

In the formula, R1 is an alkyl group (e.g., methyl group, ethyl group, propyl group, etc.) or a substituted alkyl group (e.g., 2
-Hydroxyethyl group, 2-methoxystyryl, (, carboxymethyl group, 2-carboxyethyl group''g).

R2 is alkyl 2! i (for example, methyl group, ethyl group, etc.), or aryl group (for example, phenyl group).

p-hydroxyphenyl group, naphthyl group, thienyl group, etc.).

Z is usually a nonmetallic atomic group necessary to form a nitrogen-containing bicyclic group used in cyanine dyes, such as benzothiazoles (benzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, etc.), Naphthothiazoles (α-naphthothianol, β-naphthothiazole, etc.), benzoselenazoles (benzoselenazole,
5-chlorobenzoselenazole, 8-methoxybenzoselenazole, etc.), naphthoselenazole (α-naphthoselenazole, β-naphthoselenazole, etc.), benzoxazole (benzoxazole, 5-methylbenzoxazole, 5- phenylbenzoxazole, etc.), naphthoxazole (α-naphthoxazole, β-naphthoxazole, etc.).

Specific examples of compounds represented by the above general formula include those having a chemical structure that is a combination of Z, R+ and R2, and many of these compounds exist as known substances. Therefore, it is possible to appropriately select and use these known materials.

Further, preferred sensitizers in the present invention include sensitizers 1 described in U.S. Pat. No. 4,082,888, such as 2-[
Bis(2-furoyl)methylene l-3-methylbenzothiazoline, 2-[bis(2-thinoyl)methylene]-3
-Methylbenzothiazoline, 2-[bis(2-furoyl)methylene 1-3-methylnaf) [1,2-d]
Examples include thiazoline.

Furthermore, preferable sensitizers in the present invention include the following.

(i) British Patent No. 1,234,848, US Patent No. 3,9
No. 05,813, JP-A-55-24113, JP-A No. 5B-
Halogen compounds described in Publication No. 15503. A typical example of this is 2,6 di(trichloromethyl)-4-(p
-methoxyphenyl)-1,3,5-) riazine, 2-
Trichloromethyl-5-(p-methoxystyryl)-1
, 3,4-oxadiazole, anthraquinone-1-sulfonyl chloride, and the like.

(i i) M, R, Sar+der et al. Journal
l of Polymer 5ocietyJ Vol. 10, p. 3173 (1972), JP-A-51-82102
No. 52-134692. Typical examples include trimethylamine, triethanolamine, p-dimethylaminobenzoic acid ethyl ester, and the like.

(i i i) West German patent (OLS) 2,528,358
A phosphite ester compound such as triethyl phosphite described in the publication.

(iMa) Japanese Patent Application No. 1987-100500 Publication No. 1-
Mercapto compounds such as mercaptobenzimidazole.

In addition to the above, the photopolymerizable composition-containing layer of the present invention may contain additives such as a thermal polymerization inhibitor, a UV absorber, a plasticizer, a dye, or a pigment.

The compounding ratio of the composition of the photopolymerizable composition-containing layer of the present invention is 1 for the monomer of the present invention (1017) and 0 for the photopolymerization initiator.
．． O1 to 50 parts by weight is preferable, more preferably 0.1
-10 parts by weight, the binder is preferably O'-1000 parts by weight, more preferably 0-500 parts by weight, and the sensitizer is preferably 0-100 parts by weight, more preferably 0-100 parts by weight.
It is 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 composition-containing layer. It may be a support, or it may be a support in which a non-layered conductive portion is formed on the side in contact with the photopolymerizable composition-containing layer.
The conductive support, the conductive layer and the conductive part are grounded by any method.

As the conductive support (2), metal sheets (preferably made of Al or Cu), conductive paper, conductive polymer films, etc. are used, and as the support (2) having a conductive layer, for example, aluminum Vapor-deposited polyethylene terephthalate or the like is used, and the support on which the conductive portion (2) is formed is, for example, a film or paper surface with An powder or Cu powder fixed thereon by an appropriate means.

Preparation of image-forming material To prepare the image-forming material used in the present invention, the photopolymerizable! The product is mixed with one or more solvents such as ethylene dichloride, cyclohexanone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, monochlorobenzene, toluene, xylene, ethyl acetate, butyl acetate, etc., for example, by reverse reaction. It can be obtained by coating and drying using a conventional coater such as a roll coater, an air knife coater, a Meyer bar coater, or a rotary coating device such as a Whaler.

The thickness of the layer containing photopolymerizable Mi formed metal is l −1100
pL is preferred, more preferably 2 to 10 pL.

An example of the image forming material used in the present invention is shown in FIG. 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 net negative of usually four colors from the original using a color scanner or the like, the net 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 200V, more preferably 150V. The potential difference here is Kawaguchi Electric's Electrostatic Paper Analyzer 5P-
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 area has a high electrical resistance (it retains a sufficiently high initial charge, and the rate of decay of that charge is not only extremely low, but also has the characteristic that the charge in the unexposed area decays quickly to virtually zero). have

For this reason, a portion with residual charges is formed in the exposed area 2A by the corona charger 3, and the '11 charge in the unexposed area 2B flows out through the ground, and the residual charges cause static 'Ff' and latent charge. Image 3A is formed.

(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 the isoparaffinic liquid featured in the Isopar G product line. 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 control agent or stabilizer, which helps maintain the electrostatic charge on the toner particles.The developer solution may contain a dispersed wax to give the toner self-fixing properties. A description of a developer of this type which can be used in particular in carrying out the process of the invention is given in EP-A-098,084 (published January 11, 1984).

In the present invention, to obtain a color image.

Y (yellow) toner, M (magenta) toner, C
Development may be repeated using four types of toner: (cyan) toner and Bk (black) toner.

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

[9. Bright effect] According to the present invention, it is possible to obtain a high-density transferred image without background smearing, and it is possible to repeatedly obtain transferred images of the same density with good reproducibility. A method of forming an image can be provided.

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

A photopolymerizable coating solution having the following composition was coated on a 1100B thick aluminum-deposited polyethylene terephthalate film to a thickness of 5 cm, and a 20 g+s thick polypropylene cover sheet was laminated on top of this coating film.

Styrene-methyl methacrylate (molar ratio 70:30) copolymer 5.0
g Pentaerythritol tetraacrylate 3.68 Photopolymerization initiator Xg Chain transfer agent or sensitizer Yg Methyl ethyl ketone 20g Methyl cell solve acetate
) 20g of this film was overlaid with a negative mask and imagewise exposed from a distance of 50cm using a 3kw metal halide lamp, after which the 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 Electric Co., Ltd.
It was fixed at 11.

The initial voltage VO is measured within 1 second after charging and 1
Measurements were taken at 15 second intervals up to 1 minute (VI5...veo) and 2 minutes later (V120).

% attenuation in exposed areas.

+00 (+-V120/V15) It was calculated as

The results are shown in Table 1.

Itcho margin Images were evaluated according to the following procedure.

After imagewise exposure of the film (master) with the photopolymerizable layer containing the photoinitiator described above, two aluminum drums driven by gears are placed in order to form and develop the ift simultaneously. 08~0.13m5 (3~5mil)
installed in the test equipment separated by a gap.

The lower drum has a corona discharge electrode and a toner processing device, and by rotating this drum counterclockwise, the master is completely folded. is then developed and finally the image is transferred onto paper.

Charging was performed by +8 kV corona discharge for 10 seconds.

After charging is complete, the latent image is developed by rotating the lower drum through the toner treatment position.

The image was developed using a Ricoh MRP TOCHI using an isoparaffinic solvent Isopar G as a carrier liquid.

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 transfer is purely electrostatic since the master and transfer drum are separated by a gap of 0.08-0.13 mm (3-5 mils).

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, "O" indicates good transferred image, "Δ" indicates increased solid density,
Some background stains, "x" increases solid density.

There is considerable scuffing, as shown in each item.

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.
+ A stain-free, high-density transferred image could be obtained. It was also revealed that the repeatability 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 Nicorona 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) ▲ Numerical formulas, chemical formulas, tables, etc. , or a substituted or unsubstituted heterocycle. ]