JPH0215259A - Method and device for forming image - Google Patents

Abstract

PURPOSE:To obtain in one transfer a prepress proof, which has almost the same quality as an actual printed matter and also has excellent color-reproducibility, or a small amount of printed matter by composing the device, which transfers an unexposed part onto an image receiving body, of an exposure light source, an exposure drum, and a pressure drum coming into press-contact with the exposure drum. CONSTITUTION:A UV lamp 1 is placed radially outside the exposure drum 3; an image forming material 5 and the laminated body of an original 11 are exposed; the exposure drum 3 is provided with a means 13 attracting the image forming material and with a gripping pawl 14 attaching the image receiving body. The attracting means 13 performs attraction with plural holes made in the area where the image forming material is attached, so that the laminated body is attached; after the original is peeled off the laminated body on which an image is exposed, the exposure drum 3 is turned, and the image forming material 5 is drawn between the exposure drum 3 and pressure drum 19 creating a nip. Then, the image receiving body 21, attached on the exposure drum 3, is press-bonded by means of the gripping pawl 14 and double- sided adhesive tape provided on the exposure drum 3; the image formed on a photosensitive layer is ultimately transferred onto the receiving body 21.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an image that can be formed by superimposing monochrome or multicolor images by utilizing the difference in tackiness between exposed and unexposed areas of a 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 matter as a prepress proof for color proofing or the like.

[Prior Art] Conventionally, in the field of printing industry, prepress proofing has been used as a means for checking the finish, color tone, etc. of final printed matter before printing. There are two types of prepress proofs: an overlay method and a subprint method, each of which is used depending on the purpose of use.

In the overlay method, a photosensitive layer corresponding to each color separation (separation) image is provided on each transparent base film, an image is formed on each base film by irradiation with actinic rays and development, and then each base film is registered by visual inspection. and overlap. This method has the disadvantage that the texture is significantly different from the actual printed material because it is affected by the reflected light from each overlapping film.

The server printing method is described, for example, in U.S. Patent Section 30 (5002
No. 3, No. 3,060,024, and No. 3,060,025, a plurality of images formed on each photosensitive layer corresponding to each color separation image are sequentially transferred to a single image receptor. This is used to form a pre-press proof. Each photosensitive layer may be colored to correspond to each color separation image, or each transferred image may be colored with powder color toner.

The method disclosed in U.S. Patent No. 3,060,023, etc. is as follows:
This is a method in which a photosensitive layer and an image receptor are brought into close contact with each other in a two-dimensional manner under pressure, heated, and then peeled off.

In this method, in which the photosensitive layer and the image receptor are brought into close contact with each other under pressure in a plane and then peeled off, if the working conditions such as the speed and direction of peeling are not constant, the reproduction of the transferred image will become unstable.
Non-uniformity in the reflection density of the transferred image results in fine periodic patterns and even fine directional patterns, resulting in a significant decrease in the accuracy of color reproduction, etc.

JP-A No. 59-97140, JP-A No. 61-1885
No. 37 discloses a proofing method that is applicable to both the overlay method and the subprint method.

In this proofing method, a color sheet is prepared in which a release layer, a colored photosensitive layer, and a protective film are sequentially laminated on a polyester support, and an image-receiving film is prepared in which an image-receiving layer and a protective film are laminated on a polyester support. , the emulsion side of the color sheet and the halftone negative are brought into close contact, exposed to light to form an image, and the unexposed areas are eluted with a mixture of soda carbonate, butyl cellosolve, and water. After drying, it can be used as an overlay proofing method.

Since a developer is used, continuous processing is difficult.

When used as a sub-print proofing method, the ink image formed on the above color sheet is placed on the image-receiving film at a temperature of 110°C, a pressure of 2 bars, and a speed of 60°C.
The image is transferred to an image receiving film under the conditions of m/m'in. Next, registration is performed visually or by punching on this image-receiving film, and a cyan image is transferred. The above operation is repeated for magenta and yellow in this order 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 matte film is applied to complete the proof ink sheet.

In the above method, the maintenance of color sea 1-g! The original image layer formed on the film is laminated on the film side so that it is in contact with the protective film, and exposed. Peel off the protective film after exposure,
An image is formed by pressing onto an image receptor. Therefore, since the formed image becomes a reverse image, another transfer is necessary to obtain a normal image. In this case, a protective film is interposed between the original image layer and the photosensitive layer, and light is diffused, making it difficult to obtain a highly accurate image. Further, in order to obtain a normal image by one transfer, it is necessary to expose the film side of the film having the original image layer so that it 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 increases and image quality deteriorates.

Simple proofing is also well known, in which an image forming material having a photosensitive layer is used and transferred by a letterpress proofing press. That is,
In this method, the image receptor is placed on the paper surface plate of the proof printing machine, the exposed color sheet is held on the impression cylinder, and the image is transferred while the impression cylinder rotates.

[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 on a table or the like using register pins, exposed, and then manually moved from the table or the like to the transfer device.

In color proofing, image formation is performed repeatedly in four colors, and registration and phase alignment in the four colors are important for maintaining image quality. Conventionally, most of these registrations have been done visually or by drilling holes using a pin method using a film. These methods cannot be said to be fully applicable, especially when it is desired to form a color image in a short period of time. That is, it is difficult to perform continuous processing of each process such as exposure and transfer. In addition, when the image is transferred to the image receptor manually, the quality of the image formation depends on the experience and intuition of the operator, and it is not always possible to produce a good image.

An object of the present invention is to provide an image forming apparatus and an image forming method that can provide a prepress proof or a small amount of printed material that has a texture almost equal to that of an actual printed material and excellent color reproduction accuracy in one transfer.

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

A further object of the present invention is to provide an image forming apparatus and an image forming method that can continuously create prepress proofs and the like.

[Means for Solving the Problems] The image forming apparatus of the present invention includes a support, a photosensitive layer formed on one surface of the support, and /i! , a protective film, is laminated with an original image, imagewise exposed, and a part or all of the unexposed area is transferred to an image receptor. An exposure cylinder is provided with an impression cylinder in contact with the cylinder, an exposure light source is arranged on the outside of the exposure cylinder in the radial direction, an image forming material attaching means is provided on the exposure cylinder, an image forming material holding means is provided on the impression cylinder, and the image forming material is attached to the surface of the exposure cylinder. This device leaves the protective film of the image forming material on the exposure cylinder and holds the image forming material without the protective film on the impression cylinder.

As the image-forming material, various image-forming materials can be used, such as dry method materials that form images by peel development. In particular, materials for the dry method using peel development are preferable because they are easy to operate and can be made continuous.

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

The impression cylinder is preferably installed so that it can freely contact the exposure cylinder and adjust the nip pressure between the impression cylinder and the exposure cylinder.

The impression cylinder is preferably coated with an elastic material such as rubber in order to smoothly transfer the image formed on the photosensitive layer to the image receptor.

The image forming material attachment means includes a means for sucking and fixing the material by providing a large number of holes and grooves for a vacuum means in the material attachment part of the cylinder, a means for fixing the material by static electricity, and a means for fixing it with double-sided adhesive tape. The clamp bar can be attached along the axis of the exposure cylinder by means of fixing the bar, or by any means that can fix the material on the surface of the cylinder, such as a gripper used in the impression cylinder or intermediate cylinder of a printing press. You may also use the following methods. However, when a clamp bar or the like is used as the attachment means, it is preferable to install the means radially inward from the barrel surface in order to avoid damaging the barrel surface. Preferably, the attachment means also includes a pin bar or the like for accurately positioning the image forming material on the exposure cylinder and the impression cylinder and ensuring appropriate registration and phase alignment.

The image forming material holding means installed on the impression cylinder includes means for sucking and fixing the material by opening a large number of holes etc. in the part that holds the image forming material, and means for fixing the image forming material with double-sided adhesive tape. Any means that can be used to secure the protective film to the image forming material may be used, but it is more preferable to use gripping claws, since the protective film can be smoothly separated from the image forming material.

It is also possible to employ gripping claws and suction means, sticky cheese flavor or electrostatic means as the attachment means, and to employ gripping claws as the holding means.

From the exit between the nip or gap (hereinafter referred to as nip) formed between the exposure cylinder and the impression cylinder, a protective film is left on the exposure cylinder and the image forming material without a protective film is held on the impression cylinder. It is preferable to appropriately select the materials of the protective film, the support, or the photosensitive layer so that the adhesive force between the protective layer and the protective film is weaker than the adhesive force between the photosensitive layer and the support. A release treatment may be applied to the surface of the protective film. In addition, a cut is made in the axial direction of the exposure cylinder near the forward end of the protective film, so that when the protective film is held in the impression cylinder's holding means, such as a gripping claw, the remaining part of the protective film is attached to the exposure steel. It may remain attached.

A plurality of small diameter rolls may be installed near the outer periphery of the exposure cylinder, impression cylinder, and transfer cylinder to help the image forming material or image receptor adhere to the cylinder surface and prevent the occurrence of wrinkles, etc. .

The image forming apparatus of the present invention may further include an image receptor attaching means on the exposure cylinder, and the image-exposed photosensitive layer on the impression cylinder may be transferred to the image receptor attached to the means. .

Further, the image forming apparatus of the present invention further includes a transfer cylinder having an image receptor attachment means that contacts the impression cylinder, and the image-exposed photosensitive layer on the impression cylinder is attached to the image receptor attached to the transfer cylinder. It may also be transcribed. The transfer cylinder is preferably installed so that it can freely contact the impression cylinder and adjust the nip pressure between it and the exposure cylinder.

It is preferable to provide a heating means in the image receptor attachment area of the exposure cylinder or transfer cylinder so that the image receptor can be heated to an appropriate temperature. The purpose is to smoothen the transfer of the exposed photosensitive layer to the image receptor, improve the transfer speed, and improve the reproduction accuracy of fine images. The temperature of the drum surface in the image receptor attachment area is 50 to 150°C, preferably about 60 to 110°C.

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, which includes an exposure light source, an exposure cylinder, and an impression cylinder.

A UV lamp 1 is arranged radially outside the exposure cylinder 3 and exposes the stack of the image forming material 5 and the original image 11. The original image may be a single positive or negative film when forming a monochromatic image, and a color-separated positive or negative film is used when forming a multicolor image.

The exposure cylinder is provided with suction means 13 for the image forming material and grippers 14 for attaching the image receptor. The suction means makes a large number of holes in the image forming material application area of the exposure cylinder and applies suction to apply the laminate. After the original image is peeled off from the image-exposed laminate, the exposure cylinder is rotated to introduce the image forming material 5 into the nip formed by the exposure cylinder 3 and the impression cylinder 19.

The original image may be transferred onto the impression cylinder as it is without peeling the original image from the laminate.

The impression cylinder 19 holds the introduced image forming material by attaching the double-sided adhesive tape 15 to the image forming material holding area on the surface of the impression cylinder, and the protective film 6 separated from the material is attached to the surface of the exposure cylinder. It remains as it is. The image-forming material separated from the protective film held on the impression cylinder is introduced between the nip formed between the impression cylinder and the exposure cylinder by rotation of the impression cylinder, and gripper claws 14 and The double-sided adhesive tape 15 is pressed onto the image receptor 21 attached to the exposure cylinder, and the image formed on the photosensitive layer is transferred to the image receptor. The image receptor 21 may be attached by suction means 13 which is an image forming material attachment means. It is preferable that the impression cylinder is released from contact with the exposure cylinder after the transfer is completed.

Preferably, heating means (not shown) is provided in the image receptor attachment area of the exposure cylinder. The exposure cylinder further rotates to post-expose the transferred image with a UV lamp.

FIG. 2 is a schematic side view showing an image forming apparatus according to another embodiment of the present invention, which includes an exposure light source, an exposure cylinder, an impression cylinder, and a transfer cylinder.

A gripper 14 for gripping the laminate is provided between the surfaces of the exposure cylinder 3 at the tip of the laminate in the rotational direction, and a suction means 13 is provided in the image forming material application area, and the gripper and suction remove the image forming material 5, A stack of original images 11 is attached to the surface of the exposure cylinder. A clamp bar for gripping the laminate by magnetic force is installed at the tip of the laminate in the rotational direction, and the clamp bar 16 is held in the gripping claws 14 . The laminate is gripped by a clamp bar 16 and gripping claws 14 that apply tension to the rear end of the laminate in the rotation direction of the exposure cylinder surface, and the laminate is brought into close contact with the exposure cylinder surface. Attach it. The laminate is exposed to light using a UV lamp 1 placed outside the exposure cylinder 3 in the radial direction. The exposure transfer stack is introduced by rotation of the exposure cylinder into a nip formed by the exposure cylinder and the impression cylinder.

The image forming material on the exposure cylinder is transferred to the impression cylinder side by the interaction between the gripper claw 17 installed in the surface recess of the impression cylinder and the gripper claw 14 installed on the exposure cylinder.

At this time, a half cut is made along the axial direction of the exposure cylinder near the tip of the protective film in the rotational direction, so that only the tip of the protective film moves to the impression cylinder side, and the remaining part remains attached to the exposure cylinder side. Make sure that there is. The impression cylinder is provided with a suction means 13 in the holding area of the image forming material without a protective film, so that the image forming material is brought into close contact with the impression cylinder surface, and the impression cylinder surface at the rear end in the rotational direction of the image forming material is Grip claws installed on the four parts 1
7 grips the clamp bar 16 at the rear end of the image forming material to hold the image forming material without a protective film on the impression cylinder. The image forming material transferred onto the impression cylinder is introduced into a nip formed by the impression cylinder and the transfer cylinder 23 by rotation of the impression cylinder.

An image receptor 21 is attached to the transfer cylinder 23 using a double-sided adhesive tape 15 or the like attached to the image receptor attachment area, and the image formed on the photosensitive layer is pressed onto the receptor. Preferably, a UV lamp is arranged radially outside the transfer cylinder to post-expose the image pressed onto the image receptor.

FIG. 3 shows a half-cut in the edge 9 of the protective film 6 of the image forming material 5 consisting of the support 7, the photosensitive layer 8 and the protective film 6, and the end edge of the protective film gripped by the clamp bar. One and the rest, l! 10 indicates cutting or separation. As a result, the edge portion of the protective film moves toward the impression cylinder, but the remaining protective film remains attached to the exposure cylinder. At this time, it is preferable to perform a mold release treatment on the photosensitive layer side of the protective film.

In FIG. 4, a half cut is made on the edge 9 of the protective film 6,
A state in which a portion of the remaining protection M10 is overlapped with the edge portion is shown. As a result, only the edge portion is transferred to the impression cylinder side while being held by the clamp bar, and the remaining protective film remains attached to the exposure cylinder.

In the image forming method of the present invention, in the image forming apparatus of the present invention, an image forming material and an original image are laminated and attached in this order to an exposure cylinder with a protective film on the inner surface, and the image forming material and the image forming material are exposed. The rotation of the cylinder introduces the image-forming material and the original image without a protective film into the impression cylinder, leaving the protective film on the exposure cylinder, or the image-forming material without a protective film into the nip formed by the exposure cylinder and the impression cylinder. This is a method in which the image formed on the photosensitive layer is then transferred to an image receptor.

The image receptor used in the present invention may be made of any suitable base material such as paper, coated paper, high-quality paper, or film.

When obtaining a single-color prepress proof or printed matter, the original image used in the present invention is transferred to a film made for a single color (image mask) or a transparent polyethylene terephthalate film 1 with functions such as color separation. This may be a fixed paper image mask or, if a multicolored color proof or print is to be obtained, a color separated image mask.

The image forming material used in the present invention consists of a support, a photosensitive layer formed on one side of the support, and a protective film.

As the support, a material that is stable against heat, chemicals, light, etc. and transmits actinic rays is suitable. For example, cellulose acetate, borisdylene, polyvinyl chloride,
Films or sheets made of polyethylene terephthalate, polycarbonate, polyimide, polypropylene, etc. In particular, polyethylene terephthalate films or films 1 to 1 are preferred because they have excellent transparency, thermal stability, and dimensional stability.

These supports may be used as is, or may be subjected to mold release treatment with a suitable oil-resistant substance. Examples of oil-repellent substances include silicone resins and fluororesins.

The photosensitive layer consists of (a) a photopolymerizable compound and a coloring agent, (b) a photopolymerizable compound, a thermoplastic resin, a colorant, etc., and further contains a photopolymerization initiator, a thermal polymerization inhibitor, etc. May be used together.

As the photopolymerizable compound, at least one selected from monomers, oligomers, and prepolymers is used.

Preferably, it is a compound that can plasticize a thermoplastic resin at room temperature.

As the thermoplastic resin (organic polymer binder), a thermoplastic polymer that is not photopolymerizable and has excellent compatibility with the photopolymerizable compound can be used.

As the dye and/or pigment to be contained in the photosensitive layer, conventionally known dyes and/or pigments can be used. in general,
Dyes and pigments having hues of yellow, macenta, cyan, and fluff are preferable, and metal powders, white pigments, fluorescent pigments, etc. can also be used.

For color proofing, there are yellow, red, indigo, and ink, and pigments or dyes that match these hues can be selected and used.

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

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 mold releasability of the polyethylene film itself may be utilized, or a mold release agent such as fluororesin or silicone resin may be applied.

In the image forming method of the present invention, the image may be transferred to the image receptor by introducing the image into a nip formed by an exposure cylinder and an impression cylinder to which the image receptor is attached.

Furthermore, in the image forming method of the present invention, the image may be transferred to the image receptor by introducing the image into a nip formed by a transfer cylinder to which the image receptor is attached and an impression cylinder.

The present invention will be explained below with reference to Examples. In the examples, parts indicate parts by weight, and % indicates weight %.

Example 1 Diallylisophthalate prepolymer (Daiso Isodap Mn45000 manufactured by Osaka Soda Co., Ltd.)
) 21.23 parts dipentaerythritol hexaacrylate DPHA (manufactured by Nippon Kayaku Co., Ltd.) 7.08 parts addition polymerization initiator Hensiphenone 0.5 parts 4.4 bis-ethylaminobenthophenone EAB (Hodogaya Chemical Co., Ltd.) Manufactured by Co., Ltd.
0.17 parts hydroquinone 0001
Carbon black MA-7 (manufactured by Mitsubishi Chemical Industries, Ltd.)
5,0 part 1 ~ Ruen
A photosensitive layer solution having a composition of 38.0 parts methyl ethyl ketone and 40.0 parts was prepared.

This photosensitive layer liquid was applied to biaxially stretched polyethylene terephthalate 1.
- A film (thickness: 12 μm) was coated with a dry coating layer of 2.4 μm, and then a polyethylene film (protective film) was attached to the coated surface to obtain an image forming material.

Using this image forming material, in the apparatus shown in FIG. 1, the image forming material, a positive film, and art paper were each attached to an exposure cylinder, and exposure and transfer were performed. The positive film was peeled off by hand after exposure.

Separation of the protective film from the image forming material proceeded smoothly, and the resulting transferred image was clear.

The feeding speed of the image forming material and art paper between the nips was 50 cm/min, and the linear pressure was 4. kg/cm,
The surface temperature of the exposure cylinder on the lower side of Ar I was 100°C.

Example 2 Instead of carphone black in Example 1, Lionol Yellow FG1310, Carmine 7BFG4412, and Lionol Blue FG7330 were used to prepare photosensitive layer solutions.

The photosensitive layer solution was applied to a polyethylene terephthalate film using the same method as in Example 1, and a polyethylene film was attached to obtain an image forming material. First, a color-separated positive film corresponding to Lionol Yellow FG1310 was placed on an image forming material, exposed using the apparatus shown in FIG. 1, and transferred onto the transferred image obtained in Example 1. Next, the above operation was repeated for the remaining two colors to produce a color proof in which halftone images were formed in the order of black, cyan, magenta, and yellow.

The color proof obtained was clear.

[Effects of the Invention] According to the present invention, a color proof having a texture equivalent to that of an actual printed product can be provided simply, quickly, and stably, especially in the K-print method that uses printing paper.

The present invention is applicable not only to the overlay method but also to printing in small print runs of up to several hundred copies.

According to the present invention, the quality of the obtained transferred image is good, a normal image can be obtained with one transfer, exposure and transfer (and post-exposure) can be performed continuously, and registration is easy. Therefore, a remarkable effect is achieved in that a stable image can be obtained without relying on the experience or intuition of a skilled person.

In image forming materials consisting of a support/photosensitive logging film, the protective film is thicker than the support and often has poor light transmittance.

According to the present invention, since light is exposed from the support side, there is little diffusion or scattering of light, and therefore good prepress proofs or printed materials can be provided.

According to the present invention, since the image forming material and the image receptor can be attached to the exposure cylinder, registration is relatively easy, and therefore color proofs or printed matter without misregistration can be provided.

[Brief explanation of the drawing]

1 and 2 are schematic side views of the image forming apparatus of the present invention, and FIGS. 3 and 4 show a state in which a half cut is made at the edge of the protective film of the image forming material. FIG.

Claims (1)

[Scope of Claims] 1. An image forming material consisting of a support, a photosensitive layer formed on one side of the support, and a protective film is laminated with an original image and exposed to light, and the unexposed areas are exposed. An apparatus for transferring a part or all of the image onto an image receptor, the apparatus comprising an exposure light source, an exposure cylinder, and an impression cylinder in contact with the exposure cylinder, the exposure light source being arranged radially outside of the exposure cylinder. , an image forming material attachment means is provided on the exposure cylinder and an image forming material holding means is provided on the impression cylinder, a protective film of the image forming material attached to the surface of the exposure cylinder is left on the exposure cylinder, and the image forming material without the protective film is placed on the impression cylinder. An image forming apparatus characterized in that the image forming apparatus is configured to hold the image. 2. The image forming apparatus according to claim 1, wherein the exposure cylinder is provided with image receptor attachment means. 3. The image forming apparatus according to claim 1, further comprising a transfer cylinder having an image receptor attaching means in contact with the impression cylinder. 4. In the image forming apparatus according to claim 1, the image forming material and the original image are laminated and attached in this order to the exposure cylinder with a protective film on the inner surface, and the image-exposed laminate or image forming material is exposed by rotation of the exposure cylinder. is introduced between the nip formed by the exposure cylinder and the impression cylinder, the protective film is left on the exposure cylinder and the unprotected imaging material and the original, or the unprotected imaging material is retained by the impression cylinder; An image forming method characterized by transferring an image formed on a photosensitive layer to an image receptor. 5. In the image forming method according to claim 4, the image forming method is characterized in that the image is transferred to the image receptor by introducing the image into a nip formed by an exposure cylinder and an impression cylinder to which the image receptor is attached. Method. 6. The image forming method according to claim 4, wherein the image is transferred to the image receptor by introducing the image into a nip formed by a transfer cylinder to which the image receptor is attached and an impression cylinder. .