JPH0642061B2 - Image forming apparatus and image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is an image capable of forming an image by superimposing a single color or a multicolor utilizing the difference in the adhesiveness of the exposed portion and the unexposed portion of the photosensitive layer. The present invention relates to a forming apparatus and an image forming method. More specifically, the present invention relates to an image forming apparatus and an image forming method capable of obtaining a transfer material similar to a printed material as a color proofing prepress proof or the like.

[Prior Art] Conventionally, in the printing industry, a prepress proof has been used as a means for confirming the finish, color tone and the like of a final printed matter before printing. This prepress proof has an overlay method and a surprint method, and they are used properly according to the purpose of use.

In the overlay method, each transparent base film is provided with a photosensitive layer corresponding to each color separation (color separation) image, an image is formed on each base film by irradiation with active light and development, and then each base film is visually registered. And stack them. This method is affected by the reflected light from the superposed films, and therefore has the drawback that the texture is significantly different from the actual printed material.

The surprint method is, for example, US Pat. No. 3060023.
Nos. 3060024 and 3060025, a plurality of images formed on each photosensitive layer corresponding to each color separation image are sequentially transferred to a single image receptor. It forms a prepress proof.
Each photosensitive layer may be colored corresponding to each color-separated image, or each transferred image may be colored with powder color toner.

The method disclosed in US Pat.
In this method, the photosensitive layer and the image receptor are planarly pressed and brought into close contact with each other, heated, and then peeled off. In this method in which the photosensitive layer and the image receptor are planarly pressure-bonded and then peeled off,
If the work conditions such as peeling speed and direction are not constant, the reproduction of the transferred image will be unstable, resulting in uneven reflection density of the transferred image, fine periodic patterns, and even fine directional patterns. As a result, the accuracy of color reproduction is significantly reduced.

JP-A-59-97140 and 61-1885.
Japanese Patent Publication No. 37 discloses a proofing method applicable to both the overlay method and the surprint method.
This proofing system prepares a color sheet in which a peeling layer, a colored photosensitive layer and a protective film are sequentially laminated on a polyester support, and an image receiving film in which an image receiving layer and a protective film are laminated on a polyester support. The emulsion surface of the color sheet and the halftone negative image are brought into close contact with each other, exposed to form an image, and the unexposed portion is eluted with a mixed solution of sodium carbonate, butyl cellosolve and water. After drying, it can be used as overlay proofing. Since a developer is used, it is difficult to make it continuous.

When used as surprint proofing, the image formed by the black ink formed on the color sheet on the image receiving film is at a temperature of 110 ° C, a pressure of 2 bar, and a speed of 60 cm / m.
It is transferred to the image receiving film under the condition of in. Then, the image-receiving film is visually or punched to be registered, and a cyan image is transferred. The above operation is repeated in the order of magenta and yellow to obtain a color image. The obtained color image is transferred to an image receptor which is a transfer target. To reduce the gloss of the transferred image, a mattized film is applied to complete the proofing sheet.

In the above method, the image layer formed on the film on the protective film side of the color sheet is laminated so that the original image layer is in contact with the protective film and exposed. After the exposure, the protective film is peeled off, and the image is formed by pressing it on the image receptor. Therefore, the formed image becomes a reverse image, and therefore it is necessary to transfer it again in order to obtain a normal image. In this case, since a protective film is interposed between the original image layer and the photosensitive layer, light is diffused and it is difficult to obtain an image with high accuracy. In order to obtain a normal image by one transfer, it is necessary to expose the film having the original image layer so that the film side is in contact with the protective film. In this case, since the film having the original image layer and the protective film are interposed between the original image layer and the photosensitive layer, there is a drawback that light diffusion due to exposure becomes large and the image quality is deteriorated.

Simple proofing in which an image forming material having a photosensitive layer is used and transferred by a relief proof printing machine is also well known. That is,
This is a system in which an image receptor is placed on a paper platen of a proof printing machine, an exposed color sheet is held on an impression cylinder, and transferred while rotating the impression cylinder.

[Problems to be Solved by the Invention] In any of the above methods, image exposure and transfer are
The image forming material and the original image are fixed and exposed on a table or the like by using a register pin or the like, and then transferred from the table or the like to a transfer device by hand.

In color proof, images are formed by repeating four colors, and registering and phase matching in the four colors are important for maintaining image quality. Conventionally, most of these registrations are made by a visual or pin type perforated film. It is difficult to say that these methods are sufficiently applicable, especially when it is desired to form a color image in a short time. That is, it is difficult to continuously perform each process such as exposure and transfer. Further, when the transfer to the image receptor is a manual method, the quality of the image formation depends on the experience and intuition of the operator, so that a good image cannot always be obtained.

An object of the present invention is to provide an image forming apparatus and an image forming method capable of providing a prepress proof or a small amount of printed matter having a texture substantially equal to that of an actual printed matter and excellent in color reproduction accuracy by one transfer.

A further object of the present invention is to provide an image forming apparatus and an image forming method that can perform exposure and transfer uniformly and easily.

A further object of the present invention is to provide an image forming apparatus and an image forming method capable of continuously producing a prepress proof and the like.

[Means for Solving the Problems] In the image forming apparatus of the present invention, an image forming material including a support and a photosensitive layer formed on one surface of the support is laminated with an original image to perform image exposure. A device for transferring a part or all of the unexposed portion to the image receptor, the device comprising an exposure light source, an exposure cylinder, and a transfer cylinder in contact with the exposure cylinder,
A means for arranging the exposure light source on the inner side in the radial direction of an exposure cylinder formed of a light-transmitting material, providing a means for attaching an image forming material to the exposure cylinder, and holding an image receptor on the transfer cylinder. Is a device provided with.

As the image forming material, various image forming materials such as a material for a dry method for forming an image by peeling development can be used. A material for a dry method by peeling development is preferable because the operation is simple and the operation can be continuous.

The light source for exposure may be any light source such as a UV lamp as long as it can cure the photosensitive layer corresponding to the non-image area.

The exposure cylinder is preferably made of a material such as glass or acrylic resin that has excellent light transmittance and is stable against heat and the like.

The transfer cylinder is preferably installed so that it can be brought into contact with the exposure cylinder and the nip pressure between the transfer cylinder and the exposure cylinder can be adjusted. The transfer cylinder may be coated with an elastic material such as rubber in order to facilitate transfer of the image formed on the photosensitive layer of the image forming material held on the transfer cylinder to the image receptor.

The image forming material impregnating means installed on the exposure cylinder is provided with a large number of holes or grooves for vacuuming means in the material impregnating region of the cylinder or a part thereof, for example, a peripheral portion of the material impregnating region, to suck and fix the material. A means for fixing the material on the surface of the exposure drum, such as a means for fixing, a means for fixing with double-sided adhesive tape, a means for fixing with static electricity, a means for mounting a plurality of clamps along the axial direction of the exposure cylinder, and a means for fixing with the clamps. Any means can be adopted if it exists. When a clamp or the like is used as the attachment means, the means is installed in the concave portion provided on the surface of the exposure drum. Alternatively, it is preferable to provide a concave portion in a portion of the transfer cylinder that comes into contact with the clamp, or to cut the transfer cylinder in a tangential direction so that the surface of the transfer drum is not damaged. Further, in the attachment means, the image forming material is accurately aligned and registered on the exposure cylinder and the transfer cylinder,
It is preferable that a pin bar or the like is also provided in parallel in order to ensure proper phase alignment.

The image receptor holding means installed on the transfer cylinder includes means for opening a large number of holes or the like in the area for holding the image receptor, means for sucking and fixing the receptor, means for fixing with a double-sided adhesive tape or static electricity, clamp, etc. Any means that can fix the body to the transfer cylinder may be used, but a pin bar or the like may be used to accurately align the image forming material with the image receptor and the phase matching when producing a color proof or the like. It is preferable to place them side by side. Also, the exposure cylinder and /
Alternatively, a plurality of small-diameter rolls may be arranged in the vicinity of the outer peripheral surface of the transfer cylinder, and the image forming material and / or the image receptor may be brought into close contact with the surface of the transfer drum to prevent wrinkles and the like from occurring.

It is preferable to attach a protective film on the side of the photosensitive layer when the image forming material is attached to the exposure cylinder, from the viewpoint of protecting the photosensitive layer in the unexposed state, and the protective film is colored in black or the like. It is preferable from the standpoint of preventing image quality deterioration due to reflection of light during exposure. A black sheet may be placed further on the protective film.

In order to facilitate the separation of the protective film on the surface of the exposure cylinder, the protective film, the material of the support or the protective film should be made so that the adhesive force between the photosensitive layer and the protective film is weaker than the adhesive force between the photosensitive layer and the support. It is preferable to appropriately select the material of the photosensitive layer. Release treatment may be performed on the surface of the protective film. Further, a half cut may be inserted in the axial direction of the exposure cylinder near the edge of the protective film and peeled off from the cut portion to facilitate separation of the protective film from the image forming material.

It is preferable to provide a heating means in the image-receptor attachment region of the transfer cylinder so that the image-receptor can be heated to an appropriate temperature. This is because the transfer of the exposed photosensitive layer to the image receptor is smoothed, the transfer speed is improved, and the precision of reproducing a fine image is improved. The temperature of the body surface in the image receptor attachment region is 50 to 150 ° C., preferably 60 to 150 ° C.
It is about 110 ° C.

When it is necessary to perform post-exposure to increase the film strength of the image transferred to the image receptor, a light source installed inside the exposure cylinder or a light source installed outside the transfer cylinder in the radial direction is used. Exposure may be performed.

Embodiments of the apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view of an image forming apparatus of the present invention including an exposure light source, an exposure cylinder, and a transfer cylinder.

The UV lamp 1 is arranged on the inner side of the exposure cylinder 3 in the radial direction, and from the outer side, the black sheet, the image forming material, and the original image are sequentially exposed to the laminate 4 laminated on the exposure cylinder 3 as the photosensitive layer and the outer side. The original image may be a single positive or negative film when forming a monochrome image, and a color-separated positive or negative film is used when forming a multicolor image.

A clamp 5 is provided on the surface of the exposure drum 3, and the laminate 4 is brought into close contact with the surface of the exposure drum by the clamp. FIG. 2 shows that the original image 7, the image forming material 8 and the black sheet 9 are sequentially laminated on the exposure drum and held by the clamp, and the black sheet 9 has a half edge along the axial direction of the exposure drum. Put a cut,
The state where the black sheet 7 is peeled from the half-cut portion after exposure is shown. After peeling the black sheet 9 from the imagewise exposed laminate 4, the exposure cylinder is rotated to introduce the image forming material 8 and the original image 7 between the nip formed by the exposure cylinder 3 and the transfer cylinder 11.

The transfer cylinder 11 has a shape in which a portion of the exposure cylinder that comes into contact with the clamp 5 is partially cut off in the tangential direction to eliminate contact between the clamp and the transfer cylinder between the nips. The image receptor 15 is held by the double-sided adhesive tape 13 on the transfer cylinder. The image-forming material with the photosensitive layer exposed on the surface is introduced into the nip formed between the exposure cylinder and the transfer cylinder by the rotation of the exposure cylinder and pressure-bonded to the image receptor 15 to form a photosensitive layer. The transferred image is transferred to an image receptor. The transfer cylinder preferably releases contact with the exposure cylinder after the transfer is completed. It is preferable to provide a heating means (not shown) in the image receptor holding area of the transfer cylinder. Rotate the transfer cylinder further,
The transferred image is post-exposed by a UV lamp inside the exposure cylinder.

FIG. 3 shows a clamp of the exposure drum, in which a half cut is made in the edge portion 20 of the protective film of the laminate 4 formed of the image forming material 8 including the support 17 and the photosensitive layer 18 and the protective film 19. Edge portion 20 of the protective film held by and the remaining protective film 2
1 indicates that it is cut or separated. This facilitates the separation of the protective film from the photosensitive layer on the surface of the exposure drum. At this time, it is preferable to perform mold release treatment on the photosensitive layer side of the protective film. FIG. 4 shows a state in which a half cut is made in the edge portion 20 of the protective film and a part of the remaining protective film 21 is overlapped with the edge portion. This allows
Only the edge portion is held by the clamp of the exposure drum, and the remaining protective film can be easily separated.

In the image forming method of the present invention, in the image forming apparatus of the present invention, the image-exposed laminate is formed by stacking the original image and the image-forming material on the exposure cylinder in this order and the photosensitive layer being on the outer side in the radial direction of the exposure cylinder. Is inserted between the nip formed by the rotation of the exposure cylinder and the transfer cylinder holding the image receptor,
An image forming method comprising transferring an image formed on an image forming material to an image receptor.

The original image used in the present invention is an image obtained by fixing light-shielding paper to a film (image mask) prepared for a single color or a transparent polyethylene terephthalate film having a function of color coding when a monocolor prepress proof or a printed matter is obtained. It may be a mask, which is a color-separated image mask when obtaining a multicolored color proof or printed matter.

The image-forming material used in the present invention usually comprises a support and a photosensitive layer formed on one surface of the support.

As the support, a material which is stable to heat, chemicals, light and the like and which transmits actinic rays is preferable. For example, cellulose acetate, polystyrene, polyvinyl chloride,
The film or sheet is made of polyethylene terephthalate, polycarbonate, polyimide, polypropylene or the like. In particular, a film or sheet of polyethylene terephthalate is preferable because it is excellent in transparency, heat stability and dimensional stability.

These supports may be used as they are, or may be subjected to release treatment with an appropriate oil-repellent substance. Examples of the oil repellent substance include silicon resin and fluorine resin.

The photosensitive layer is composed of (a) a photopolymerizable compound and a colorant, (b) a photopolymerizable compound, a thermoplastic resin and a colorant, and further contains a photopolymerization initiator, a thermal polymerization inhibitor and the like. You may use together.

As the photopolymerizable compound, at least one selected from monomers, oligomers and prepolymers is used.
A compound capable of plasticizing a thermoplastic resin at room temperature is preferable.

As the thermoplastic resin (organic polymer binder), a polymer which is thermoplastic and has no compatibility with the photopolymerizable compound and which does not have photopolymerizability can be used.

As the dye and / or pigment contained in the photosensitive layer, those known in the related art can be used. In general,
Dyes and pigments having hues of yellow, magenta, cyan, and black are desirable, and in addition, metal powder, white pigment, fluorescent pigment, and the like can be used. For color proof, yellow,
There are red, indigo, and black ink, and pigments or dyes matching these hues can be selected and used.

The thickness of the photosensitive layer may be about 0.5 to 5 μm, and an appropriate coating amount varies depending on the dye and / or pigment contained, but 0.5 to 10 g / m ² is suitable.

Examples of the protective film used in the present invention include polyethylene film, polyethylene terephthalate film, and acetate film. When the protective film is a polyethylene film, the releasing property of the polyethylene film itself may be used, or a releasing agent such as a fluorine resin or a silicone resin may be applied. It is preferable that the protective film is colored black or the like in order to prevent reflection of light from the exposure light source.

The image receptor used in the present invention includes art paper, coated paper,
Any base material such as high-quality paper and film can be appropriately selected.

Hereinafter, the present invention will be described with reference to examples. In the examples, “part” means “part by weight” and “%” means “% by weight”.

Example 1 Diallyl isophthalate prepolymer (Daiso Isodap Mn45000 manufactured by Osaka Soda Co., Ltd.) 21.23 parts Dipentaerythritol hexaacrylate DP HA (manufactured by Nippon Kayaku Co., Ltd.) 7.08 parts Addition polymerization initiator benzophenone 0.5 part 4,4 bis-diethylaminobenzophenone (EAB Hodogaya Chemical Co., Ltd.) 0.17 part Hydroquinone 0.001 part Carbon black MA-7 (manufactured by Mitsubishi Kasei Co., Ltd.) 5.0 parts A photosensitive layer liquid having a composition of 38.0 parts of toluene and 40.0 parts of methyl ethyl ketone was prepared.

This photosensitive layer liquid is applied to a biaxially stretched polyethylene terephthalate film (film thickness 12 μm) so that the dry coating film becomes 2.4 μm to prepare an image forming material, and then a polyethylene film (protective film) is applied to the coated surface. , Black) attached,
A laminated body was obtained.

Using this image-forming material, the positive film and the laminate were attached to the exposure cylinder and exposed using the apparatus shown in FIG. Then, the protective film was separated, the exposure cylinder was rotated, and transfer was performed to the art paper held on the transfer cylinder.

The obtained transfer image was clear.

The feeding speed of the laminate and art paper into the nip was 50 cm / min, the linear pressure was 4 kg / cm, and the surface temperature of the exposure cylinder on the art paper side was 100 ° C.

Example 2 Instead of the carbon black of Example 1, each of the photosensitive layer liquids was prepared by using Rionol Yellow FG1310, Carmine 7BFG4412 and Rionol Blue FG7330.

The photosensitive layer liquid was applied to a polyethylene terephthalate film in the same manner as in Example 1, and the polyethylene film was attached to obtain a laminate. The laminate was first superposed on a color-separated positive film corresponding to Lionol Yellow FG1310, exposed using the apparatus of FIG. 1, and superposed and transferred on the transfer image obtained in Example 1. Then, the above operation was repeated for the remaining two colors to prepare a color proof in which halftone images were formed in the order of black, cyan, magenta and yellow.

The color proof obtained was clear.

[Effect of the Invention] According to the present invention, a color proof having a texture equivalent to that of an actual printed matter can be provided easily, quickly, and stably, particularly in a surprint method using a printing paper. The present invention can be applied not only to the overlay method, but also to printing a small number of copies of several hundreds.

According to the present invention, the quality of the transferred image obtained is good, a normal image can be obtained by one transfer, and exposure-transfer (and post-exposure) can be continuously performed, and registration is easy. Therefore, there is a remarkable effect that a stable image can be obtained without depending on the experience and intuition of an expert.

In a laminate of support / photosensitive layer / protective film, the thickness of the protective film is thicker than that of the support, and the light transmittance is often poor.

According to the present invention, since light is exposed from the support side, light is less diffused and scattered, and therefore a good prepress proof or printed matter can be provided.

According to the present invention, since the exposure cylinder and the transfer cylinder, which are light-transmissive, are the main components, a small space is required and the structure of the apparatus is relatively simple.

Further, according to the present invention, when the protective film is used, the protective film is simply peeled off, and when the protective film is not used, the image can be directly transferred to the image receptor, and the obtained image is a normal image. There is a remarkable effect.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an apparatus of the present invention, FIG. 2 is a partially enlarged side view showing a peeled state of a protective film on the surface of an exposure drum, and FIGS. It is a side view which shows the state which put the half cut in the edge part. 1 ... UV lamp, 3 ... exposure cylinder 8 ... image forming material, 11 ... transfer cylinder 15 ... image receptor

Claims (2)

[Claims] 1. An image forming material comprising a support and a photosensitive layer formed on one surface of the support is laminated with an original image and imagewise exposed to form an image of a part or whole of an unexposed portion. In an apparatus for transferring to a receptor, the apparatus comprises an exposure light source, an exposure cylinder, and a transfer cylinder in contact with the exposure cylinder, and the exposure light source is formed on the inner side in the radial direction of the exposure cylinder. And an image forming material is attached to the exposure cylinder, and a means for holding an image receptor is provided on the transfer cylinder. 2. The image forming apparatus according to claim 1, wherein the image forming material is laminated on the exposure cylinder in the order of the original image and the image forming material, and the photosensitive layer is on the outer side in the radial direction of the exposure cylinder. An image forming method characterized in that the image formed on the image forming material is transferred to the image receptor by inserting the image forming material into a nip formed by the rotation of the exposure drum and a transfer drum holding the image receptor. .