JPH02149852A - Image forming method - Google Patents

Abstract

PURPOSE:To improve transfer precision of an image forming method by superposing a coloring material sheet and a photosensitive sheet on a substrate after performing image-exposure of the photosensitive sheet, transferring the coloring material to an adhesive part of a photosensitive layer while heating and/or pressing the superposed materials, superposing the photosensitive layer on a final substrate and transferring the coloring material on the photosensitive layer to the final substrate. CONSTITUTION:After performing image-exposure on a photosensitive sheet constituted of a substrate provided thereon with a photosensitive layer which varies its adhesion by the effect of ultraviolet rays and a cover sheet capable of transmitting ultraviolet rays, through above cover sheet, then the cover sheet is removed. Thereafter, a coloring material sheet contg. a coloring material on/in a substrate is superposed on the photosensitive sheet, and the coloring material is transferred to an adhesive part of the photosensitive layer under heating and/or pressing the superposed product. The photosensitive layer is then superposed on a final substrate, and the coloring material on the photosensitive layer is transferred to the final substrate. Thus, an original image to be an original is reproduced precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a multicolor image forming method, and mainly relates to a multicolor image forming method used for color proofing.

"Prior Art" Conventionally, as a color printing proofing method, a printing proofing machine and a printing main machine are used to print proofs and perform color proofing. However, proofs produced by this method are expensive, time consuming, and have limited reliability.

On the other hand, in place of these printing methods, various color proofing methods using photographic methods have been developed as simpler and simpler methods.

These photographic color proofing methods include a color proofing method (prepress proofing) using 7 otobolimer, which includes an overlay method and a subprint method. The overlay method prepares multiple color proofing sheets with separated images of each color on a transparent support, and performs color proofing by overlapping these sheets (the resulting sheet is called a color test sheet). It's a method.

This overlay method is very simple and inexpensive, and has the advantage that it can be used for continuous inspection by overlaying only two or three colors each time. It becomes dark, and the incident light reflects off some sheets, giving it a shine.
Therefore, the impression received from the color test sheet has a disadvantage that the texture is very different from that of printed matter printed by a regular printing machine.

On the other hand, the subprinting process involves the superposition of several colored layers on a single support, for which various toners are brought onto a common opaque base, or photosensitive layers of corresponding colors are applied. The layers are sequentially applied onto the opaque base.

Methods of this type are described, for example, in US Pat. Nos. 3,671,236 and 3,130,637.

In this overprinting method, the color density is affected by the synthetic resin base.
It has the advantage of not being IJed, α. The method is also more similar to the original printing method and has the advantage of avoiding color distortions that occur when stacking sheets.

Furthermore, a color image is formed on the release layer by imagewise exposing a photosensitive transfer material in which a release layer made of an organic polymer, a coloring material layer, and a photosensitive layer are sequentially laminated on a temporary support, and then developing the material. A method of forming an image and then transferring this image to an arbitrary support (permanent support) using an adhesive is already well known (Japanese Patent Publication Nos. 15326-1982 and 441-49).
This method has the advantage of being used for various operations such as color proofing, overlay type, sub-print type, etc. However, when transferring, it is necessary to use adhesive for each transfer, which makes the process difficult. This method has disadvantages in that it is complicated and it is difficult to maintain alignment accuracy when transferring each color.

As a method to eliminate the complexity of these processes, a method of transferring the image onto a permanent support by applying heat and pressure after forming the image is disclosed in JP-A-47-41830, JP-A-48-9337,
It is disclosed in No. 51-5101 and the like. Especially in 1975
No. 1-5101 describes the provision of a heat-fusible polymer layer as an adhesive on a permanent support, and JP-A No. 47-41830 also describes the provision of a permanent support such as art paper or coated paper. describes a method for directly transferring images.

However, these methods have various drawbacks. That is, the final image transferred onto the permanent support is left-right reversed relative to the original, and when a thermofusible polymer is used as an adhesive, the transfer temperature is generally high due to its high melting point. For this reason, there are problems such as the dimensional stability of the support decreases due to the influence of heat, resulting in misalignment of each color during transfer. On the other hand, when a heat-melting polymer with a low melting point is used as an adhesive, there are drawbacks such as adhesion occurring after the image is formed and the surface being easily scratched.

As a method for improving the above-mentioned drawbacks, a method of transferring the image to a temporary image-receiving sheet before transferring the image to a permanent support was disclosed in Japanese Patent Application Laid-Open No. 59-971 filed by the present applicant.
It is described in No. 40. That is, in this method, a temporary image-receiving sheet with an image-receiving layer made of a photopolymerizable material provided on a support is prepared, and before the images of each color are transferred onto the permanent support, the temporary image-receiving sheet is temporarily coated. The photopolymerizable image-receiving layer includes the steps of transferring each color image to a permanent support, then retransferring it onto a permanent support, and then further exposing the entire surface to light to cure the transferred photopolymerizable image-receiving layer.

The image transfer method using the above-described temporary image-receiving sheet (hereinafter simply referred to as image-receiving sheet) is very effective in solving the above-mentioned problem α. That is, by using this method, it is possible to obtain an erect image of the mask original on the permanent support.

The photopolymerizable image-receiving layer of the image-receiving sheet contains an ethylenic polyfunctional monomer, which is a photopolymerizable material, so the photopolymerizable image-receiving layer itself is soft and can be transferred at low temperatures. After transfer, it can be easily cured by exposing the entire surface to light.

That is, there are advantages in that no adhesion occurs after image transfer, and the final image has high scratch resistance.

In the image-receiving sheet used in the method described in JP-A No. 59-97140, the a-adhesive force between the photopolymerizable image-receiving M (i.e., the photopolymerizable adhesive layer) and the support is in the unexposed state. Therefore, after the image-receiving photopolymerizable adhesive layer has been transferred onto the final support, peeling off the support of the image-receiving sheet material before carrying out the exposure operation will cause the transferred image-receiving Peeling streaks are likely to occur on the surface of the photopolymerizable adhesive layer. For this reason, in the method described in JP-A No. 59-97140, after transferring the image-receiving photopolymerizable adhesive layer onto the final support, the entire surface is first exposed to light to harden the photopolymerizable adhesive layer. At the same time, a method has been adopted in which the adhesive force between the photopolymerizable adhesive layer and the image-receiving sheet support is reduced, and then the image-receiving sheet support is removed.

[Problems to be Solved by the Present Invention] When an image created by a conventional method is used as a color proof, the approximation to the actual printed matter is not necessarily good. In addition, there has been a desire for an image forming method that uses a single III image forming material that can accurately reproduce the original image serving as a manuscript, and that is easy to operate and does not require operations such as full-surface post-exposure.

[Means for Solving the Problems] The object of the present invention is to (a) produce an image by passing an image through a photosensitive sheet having a photosensitive layer on a support whose tackiness changes with ultraviolet rays and a cover sheet through which ultraviolet rays can pass; Step of exposing (b) Step of removing the cover sheet (e) Step of overlapping the photosensitive sheet with a colorant sheet containing a colorant on or in the support (d) While heating and/or pressurizing Transferring the coloring material onto the adhesive portion of the photosensitive layer (e) Overlaying the photosensitive layer on the final support (r) Transferring the coloring material on the photosensitive layer to the final support This was achieved by an image forming method characterized by:

As the support for the photosensitive sheet, various materials such as films or sheets made of polyester, polycarbonate, polyolefin, polyimide, etc. can be used. A polyester film or sheet is preferable for VF in terms of dimensional stability against heat and pressure and workability.

As the photosensitive layer, for example, the compositions described in US Pat. No. 4,174,216 and US Pat. No. 3,649,268 can be used.

Examples of photosensitive sheets are shown below.

A negative-working photosensitive sheet consists of (1) a peelable cover sheet, (2) a photosensitive layer containing a non-tacky substance having ethylenically unsaturated or benzophenone type groups, and (3)
) The color can be adjusted by applying fine particles that are not sensitive to light (
toner-processable) adhesive layer, and optionally (4)
Consists of a sheet support.

A positive photosensitive sheet consists of (1) a removable support, (
2) at least one i-distant radical-initiated chain M4-extended addition polymerizable compound containing at least one terminal ethylenic group and an addition polymerization initiator activatable by actinic radiation and optionally a compatible polymer. It consists of a photocurable layer containing a molecular organic polymeric binder, and (3) a peelable cover sheet.

Using such a sheet, the cover sheet is removed after image exposure. Negative-working sheets have two layers, one of which is photopolymerizable, and positive-working sheets have a single photopolymerizable layer.

For the cover sheet, polyethylene terephthalate,
Polypropylene, polyethylene, etc. can be used.

Colorants and toners used to produce multicolor proofs are described in USP 3,620,726 and USP 3,909,326.

As the coloring material sheet, one in which a layer containing a coloring material and a binder is laminated on the above-mentioned support, a sheet in which ink is contained in a porous layer, etc. can be used.

As binders, 1. vinylidene chloride copolymers, such as vinylidene chloride/acrylonitrile, nyridane chloride/methyl methacrylate and vinylidene chloride/vinyl acetate, 2. ethylene/vinyl acetate copolymers, 3.
Cellulose ethers, such as methyl, ethyl and natural benzyl cellulose, hydroxyethyl cellulose; 4. Synthetic rubbers, such as butadiene/acrylonitrile copolymers, chlorinated isoprene and chloro-2-butadiene-1,3-polymers; 5. Polyvinyl esters. 6. Polyacrylates and polyalkyl acrylate esters, such as polymethyl methacrylate and polyethyl methacrylate, 7. Polyvinyl chloride and copolymers, such as vinyl chloride/vinyl acetate. , 8, carnatuba wax, ester wax, etc.

Examples of the ink (coloring agent 10 paint) used in the coloring material sheet include the following.

Basic components of melt-type ink Among the components of the ink, the coloring agent and baingu are particularly important. The colorant determines the hue of the ink, and in order to obtain a color record, three primary colors for printing - yellow, magenta, and cyan - are prepared.

A pigment with good fastness is used as the coloring agent, and examples thereof include Pennon Yellow G (yellow), Rhodamine Ray-47 (magenta), and 7-talocyanine blue (cyan).

Other components are sublimable dye and baingu solvent. Since the solvent evaporates after being applied to the substrate, the only components remaining in the medium are the sublimable dye and binder.

The basic components are shown in Table 1, where examples of sublimable dyes include C, 1, Dispere Yellow.

w 7 (I'-'-), C, 1, Di s
p e r e Red60 (buying), C, 1
, So I vent Blue 80 (cyan), etc. The sublimability of the dye is an important factor determining the quality of the transferred record.

Table 1 Examples of basic components of sublimation inks Most of the currently known sublimable dyes are used for M&textile printing, and a small amount of sublimation starts from 100"0".
The optimum temperature for printing is 170-200°C. In addition to sublimation properties, the dye used in sublimation ink must have a molecule of 1 (approximately 230 to 370) that easily diffuses into the transfer paper, and P
It does not have ionic groups (sulfone group, carboxyl group*) and has polar groups (
hydroxyl group, amino group, etc.) and good color reproducibility in recording.

Cellulose resin is used as the binder.

Unlike melt-type binders, dye-sublimation binders do not adhere to the receiving paper during transfer; the binder is used to hold the dye on the substrate. Characteristics required of the binder include low affinity with the dye so as not to hinder the sublimation of the dye.

The porous layer satisfies the following requirements: it can hold ink and it can discharge ink under pressure; for example, the average particle size of the pores is 1 to 50 μ;
It is a spongy or spongy debris with many uniform pores. Examples of porous layers include foamed plastic films or sheets, porous plastic films or sheets, blotting paper, filter paper, high-quality copier paper, rough paper, and the like.

The thickness of the porous layer varies depending on the use of the obtained image forming material, but is usually about 0.1 to 1+am. Furthermore, two or more layers of the above films, sheets, papers, etc. can be stacked as the porous layer.

As the ink retained in the porous layer, high viscosity inks such as letterpress ink, offset ink, and screen ink are preferred for reasons such as storage stability, but low viscosity inks such as gravure ink can also be used. Note that it is also possible to use an ink with a higher viscosity than normal printing ink.

Furthermore, in addition to general oil-based ink, ultraviolet curable ink can also be used as the ink. The amount of ink contained in the porous layer varies depending on the M, class, etc. of the porous layer, but is usually about 10 to 500 g/w2.

These sublimation inks or inks retained in the porous layer are applied to areas of the photosensitive layer that have become tacky due to imagewise exposure to ultraviolet rays or areas that have not lost their tackiness even after exposure to ultraviolet rays. θ: and then retransferred onto a support such as paper. At this time, only the ink is transferred to the support such as paper, and the photosensitive layer is not substantially transferred, and furthermore, a part of the ink may remain on the photosensitive layer.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

"Example" Example 1 A solution having the following composition was applied to a polyethylene terephthalate film having a thickness of 100 μm, which had been surface-treated by electrostatic discharge at 0.093 coulombs/2 molars, at a dry weight of 40 ωg.
/dI+1'', and after drying, a polypropylene cover sheet was provided to prepare a photosensitive sheet.

Polymethyl methacrylate 41.54g (M,
W, 200,000 to 300,000) and No (351,86° acryloxy-2-hydroxypropyl) ether (2-chlorophenyl-4,52+2 o).

-7 fluorinyl imidazolyl 2H form) 2-(stilvil-4°') -2,20g (s7to1
°, 2', 4,5) -1,2,3-triazole = 21-sulfonic acid phenyl ester 2-mercaptobenzoxazole 1,50 ° Polyethylene oxide 0.708 (M, W, 6
00000) Methanol 20.7 og Methylene chloride 323.70 g A magenta coloring material sheet was prepared for a dog by the following method.

7 Otomer 3082 (photopolymerizable compound of epoxidized vegetable oil acrylate manufactured by Sannopco), oil-soluble dye (o
il pink312+o-gumine type B, C, 1,4
5170, Orient Chemical Industry! 1! The initiator (Glochiea 1173.2-hydroxy-2-methylpropiophenone, manufactured by Merck & Co.) was added to 76.3% of the photopolymerizable compound.
, 19.0% dye, 4.7% initiator, methyl enalkene), high quality blotting paper (manufactured by Life, thickness 0.2311).
++ impregnated with a). In addition, the ink viscosity during impregnation is approximately 1
000 cps/25°C. Further, the ink content was about 100 H/m2. During lamination, methyl ethyl ketone was removed by drying.

Furthermore, do the same as above except for replacing the coloring material with the following.
Colorant sheets of other colors were created.

Yellow o -: o+I yellow107 (Orient Chemical Industry) Cyan: oil blue 603 (same as above)
Black: oil blackHBB (same as above) The reflection density of the colorant used in the porous layer in each colorant sheet was according to RD-514 (manufactured by Macbeth).

The photosensitive sheet described above was exposed for about 30 seconds from a distance of 50 cm using a 2 kW high pressure mercury lamp.

After exposure, the cover sheet of the photosensitive sheet was removed, combined with a coloring material sheet for yellow, and the coloring material was transferred using a laminator by applying heat and pressure.

This colorant was further transferred to the paper by applying heat and pressure.

When this operation was repeated for the other three colors in the order of magenta, cyan, and black, a multicolor image with high dot gain and good reproducibility of the original image was obtained.

Example 2 A photopolymerizable composition was prepared by mixing the following ingredients.

Ingredients Part by weight Polymethyl methacrylate 32.40 (molecular weight 3
0,000, density 1.13 g/cc) trimethylolprobant 35.60 methacrylate 2-0-chlorophenyl-1,58 4,5-bis(methoxyphenyl)imidazolyl dimer 2-flucaptobenzothiazole 0.79 polyoxyethylene lauri 7.90 ether This mixture was dissolved in methylene chloride (20% solution) and then coated onto a 25 μW thick polyethylene terephthalate support and 25 μII+ thick was applied onto this coating at room temperature. Laminated with a polypropylene cover sheet. This cover sheet could be removed at room temperature without imparting any substantial FJ''F to the photopolymerizable layer.

When the same procedure as in Example 1 was carried out using the melt-type ink sheet described in the text as a colored sheet, a multicolor image with many dots and good reproducibility was similarly obtained.

Claims (1)

[Scope of Claims] (a) A step of exposing an image through a photosensitive sheet having a photosensitive layer whose adhesiveness changes with ultraviolet rays and a cover sheet through which ultraviolet rays can pass on a support (b) said cover sheet (c) superposing the photosensitive sheet with a colorant sheet containing a colorant on or in the support; (d) applying heat and/or pressure to the binding portion of the photosensitive layer; An image forming method comprising: (e) transferring the coloring material; (e) superposing the photosensitive layer on a final support; (f) transferring the coloring material on the photosensitive layer to the final support.