JPH0664334B2 - Image forming apparatus and image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an image forming apparatus capable of forming an image by superimposing multiple colors utilizing the difference in the adhesiveness between the exposed portion and the unexposed portion of a photosensitive layer. 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 thus has a drawback that the texture is significantly different from the actual printed matter.

The surprint method is, for example, US Pat.
As disclosed in Nos. 060024 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 to obtain a prepress proof. To form. Each photosensitive layer may be colored corresponding to each color-separated image, or each transferred image may be colored with powder color toner.

The system disclosed in U.S. Pat. No. 3060023 and the like is a system in which 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, the reproduction of the transferred image becomes unstable unless the working conditions such as the peeling speed and direction are constant, and the transferred image Unevenness in reflection density, fine periodic patterns, and fine patterns with fine directionality are generated, and accuracy of color reproduction and the like is significantly reduced.

JP-A-59-97140 and JP-A-61-188537,
It discloses a proofing method applicable to both the overlay method and the surprint method. In this proofing system, a color sheet is formed by sequentially laminating a release layer, a colored photosensitive layer and a protective film on a polyester support, and an image receiving film is prepared by laminating an image receiving layer and a protective film 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.

In the case of use as a surprint proofing, the black image formed on the color sheet on the image receiving film is transferred to the image receiving film under the conditions of a temperature of 110 ° C., a pressure of 2 bar and a speed of 60 cm / min. 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 original 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 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 in one processing.

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 multicolor prepress proof or 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. However, in an apparatus for transferring a part or all of the unexposed portion to an image receptor, the apparatus includes a common impression cylinder having an image receptor holding means, and at least two of the common impression cylinders radially outside the common impression cylinder. A transfer cylinder having an image forming material affixing means in contact with a common impression cylinder, an exposure cylinder having an image forming material affixing means in contact with the transfer cylinder on a radial outside of the transfer cylinder, and a radial outside of the exposure cylinder. And at least two light sources for exposing the image-forming material, which are arranged in.

As the image forming material, various image forming materials such as a material for a dry method which forms an image by a peeling phenomenon can be used. In particular, a material for a dry method due to a peeling phenomenon is preferable because the operation is simple and can be 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 common impression cylinder comprises at least two transfer cylinders and at least two image receptor post-exposure light sources radially outside thereof. The transfer cylinder and the light source for post-exposure may be two in the case of obtaining a color prepress proof of two colors or a printed matter, but in the case of multicolor printing such as three or four colors, a common impression cylinder is used according to the number of colors. It is preferable to arrange it around. The common impression cylinder has a diameter larger than that of the transfer impression cylinder, and the transfer impression cylinder is arranged around the common impression impression cylinder.

The image receptor holding means of the common impression cylinder is provided with a large number of holes or grooves for the vacuum means in the receptor holding portion of the common impression cylinder, and means for sucking and fixing the receptor, and fixing with the double-sided adhesive tape. Means, means for fixing by static electricity, means for fixing a clamp bar along the axial direction of the common impression cylinder, and means for fixing by this bar, fixing the material on the surface of the cylinder such as the gripper used in the impression cylinder or intermediate cylinder of the printing machine. Any means may be adopted as long as it is possible. However, when a clamp bar or the like is used as the attachment means, it is preferable that the means is provided so as to have a concave portion on the surface of the body so as to be located radially inward of the surface of the body, since the surface of the body is not damaged. Further, it is preferable that a pin bar or the like is also arranged in parallel with the holding means in order to align the image forming material on the transfer cylinder with the character and to perform proper registration and phase alignment.

The transfer cylinder is preferably installed so as to be freely contactable with the common impression cylinder and to adjust the nip pressure between the transfer impression cylinder and the common impression cylinder. The transfer cylinder is preferably covered with an elastic material such as rubber in order to facilitate the transfer of the image formed on the photosensitive layer to the image receptor. Usually, it is preferable to wind a rubber blanket.

The image forming material adhering means installed on the transfer cylinder and the exposure cylinder is a means for making a large number of holes in the material adhering portion of the transfer cylinder or the exposure cylinder to suck and fix the material, a means for fixing with a double-sided adhesive tape, an electrostatic charge. Fixing means, means for fixing a clamp bar along the axial direction of the transfer cylinder or exposure cylinder, and fixing by the bar, the material can be fixed to the surface of the cylinder such as the gripper used in the impression cylinder or intermediate cylinder of the printing machine Any means may be adopted as long as it is one. However, when a clamp bar or the like is used as the attachment means, it is preferable that the means is provided on the surface of the body so as to be recessed so as to be located radially inward of the surface of the body in order not to damage the surface of the body. Further, it is preferable that the attachment means aligns the image-forming material on the transfer cylinder and the exposure cylinder in a proper manner, and a pin bar or the like is also provided in parallel for proper registration and phase alignment.

When the protective film is attached to the transfer cylinder and the exposure cylinder, when the protective film is separated between the nips, a gripper nail is used, because it facilitates the separation of the protective film from the image forming material. preferable. Further, as the attachment means, a gripper, a suction means, an attachment tape or an electrostatic means may be used in combination.

From the exit between the nip or the gap formed between the exposure cylinder and the transfer cylinder (hereinafter referred to as the nip), the protective film is left on the exposure cylinder and the image forming material without the protective film is attached to the transfer cylinder, or In order to facilitate the separation of the protective film on the body, the protective film, the material of the support or the photosensitive material should be set 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 conductive layer. Release treatment may be performed on the surface of the protective film. In addition, a cut is made in the axial direction of the exposure cylinder near the front end of the protective film in the traveling direction, and when the protective film is gripped by the attachment means of the transfer cylinder, for example, the gripper nails, the remaining portion of the protective film becomes the exposure cylinder. It may be left attached.

Multiple small-diameter rolls are installed near the outer circumference of the exposure cylinder, common impression cylinder, and transfer cylinder to help the image-forming material or image receptor adhere to the cylinder surface and prevent wrinkles from occurring. Good.

It is preferable that a heating means is provided in the image receptor attachment region of the common impression cylinder so that the image receptor can be heated to an appropriate temperature. This is for smoothing the transfer of the exposed photosensitive layer to the image receptor, improving the transfer speed, and improving the precision of reproducing fine images. The temperature of the body surface in the image receptor-attached region 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 side view of the image forming apparatus of the first invention including an exposure light source, an exposure cylinder, a transfer cylinder, and a common impression cylinder.

The UV lamp 1 is arranged on the outer side of the exposure cylinder 3 in the radial direction, and the laminate 12 in which the protective film 5, the image forming material 7 and the original image 11 are laminated in this order on the exposure cylinder 3 is exposed. The original image uses a color-separated positive or negative film.

The exposure drum 3 is provided with suction means 13 for the laminate 12. The suction means attaches the laminated body by making a large number of holes in the image forming material attachment area of the exposure cylinder and absorbing the holes. The areas of the protective film 5 and the image forming material 7 may be made smaller than the original image 11 so that the original image can be suctioned. In this embodiment, the square-shaped top sheet 6 with the inside cut out is laminated from the peripheral edge of the laminated body 12 to the outer edge portion, and the original sheet 11 is brought into close contact with the image forming material 7 by sucking the top sheet. The suction means may be divided into several groups so that suction and release can be performed individually.

Original image 11 and topsheet 6 from image-wise exposed laminate 12
After peeling off, the exposure cylinder 3 is rotated to introduce the protective film 5 and the image forming material 7 between the nip formed by the exposure cylinder 3 and the transfer cylinder 15. By adopting a gripper change means such as a gripper nail, the original image may not be peeled off from the laminated body and may be directly transferred onto the transfer cylinder. It is preferable that the exposure cylinder releases contact with the transfer cylinder after the transfer of the image forming material onto the transfer cylinder is completed.

The image forming material introduced by attaching the double-sided adhesive tape 17 to the image forming material holding area on the surface of the transfer cylinder is attached to the transfer cylinder 15, and the protective film 5 is separated on the transfer cylinder. The protective film 5 may be left attached to the surface of the exposure drum.

The image forming material with the protective film separated on the transfer cylinder is introduced into the nip formed between the transfer copper and the common impression cylinder 16 by the rotation of the transfer cylinder, and installed in the recess of the common impression cylinder. The gripper 19 and the suction means 13 press-contact the image receptor 21 held on the common impression cylinder to transfer the image formed on the photosensitive layer to the image receptor. The image receptor 21 may be attached with a double-sided adhesive tape or the like. The transfer cylinder preferably releases contact with the common impression cylinder after the transfer is completed. A heating means (not shown) is preferably provided in the image receptor holding region of the common impression cylinder. The common impression cylinder rotates further, and the transferred image is post-exposed by the UV lamp 1. A color prepress proof or a color printed matter can be obtained by repeating the above operation for other exposure cylinders and transfer cylinders arranged around the common impression cylinder.

FIG. 2 shows an embodiment in which the image forming material is changed from the exposure cylinder to the transfer cylinder.

The protective film 5, the image forming material 7, and the original image 11 are laminated in this order from the exposure cylinder side, the gripping member 25 is held in the concave portion of the exposure cylinder surface at the front end in the rotational direction of the laminate 12, and the suction means 13 is attached to the image forming material attachment area.
Is provided, and the laminate is attached to the surface of the exposure drum by the gripper and suction means. A clamp bar 23 for holding the laminated body is installed at the tip of the laminated body in the rotation direction, and the clasp bar is gripped by a gripper 25. The concave portion of the exposure drum surface at the rear end of the laminated body in the rotational direction is held by the clamp bar 23 and the gripper 25 which applies tension to the rear portion in the rotational direction, and the laminated body is brought into close contact with the exposed drum surface. Attach it.
The laminated body is exposed by a UV lamp 1 arranged outside the exposure cylinder 3 in the radial direction. After the exposure, the laminate is introduced into the nip formed by the exposure drum 3 and the transfer drum 15 by rotating the exposure drum.

The image forming material on the exposure cylinder moves to the transfer cylinder side due to the interaction between the gripper nail 27 installed on the surface concave portion of the transfer cylinder 15 and the gripper nail 25 installed on the exposure cylinder. At this time, a half cut is made in advance in the vicinity of the front end of the protective film 5 in the rotational direction along the axial direction of the exposure cylinder, only the front end of the protective film moves to the transfer cylinder side, and the remaining protective film remains in the exposure cylinder. Keep attached to the side. The transfer cylinder is provided with a suction means 13 in the area where the image forming material having no protective film is attached so that the image forming material is brought into close contact with the surface of the transfer cylinder, and at the same time, the concave portion of the transfer cylinder surface at the rear end of the image forming material in the rotation direction. Gripper installed in
The clamp bar at the rear end of the image forming material is gripped by 27, and the image forming material having no protective film is attached to the surface of the transfer cylinder. Image forming material without a protective film that has been transferred to the transfer cylinder,
When the transfer cylinder is rotated, it is introduced into the nip formed by the transfer cylinder and the common impression cylinder, and the image formed on the photosensitive layer is transferred to the image receptor.

FIG. 3 shows that a half cut is made in the edge portion 29 of the protective film of the laminate 12 formed of the image forming material 7 composed of the support 8 and the photosensitive layer 9 and the protective film 5, and the edge of the protective film is cut. It shows that the edge portion 29 and the remaining protective film 30 are cut or separated. This can facilitate separation of the protective film from the photosensitive layer on the surface of the transfer cylinder or between the nip between the exposure cylinder and the transfer cylinder. At this time, it is preferable to perform a 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 29 of the protective film and a part of the remaining protective film 30 is overlapped with the edge portion. This allows
It is easy to separate the remaining protective film from the photosensitive layer.

In the image forming method of the present invention, in the image forming apparatus of the present invention, an image forming material (so that the protective film faces the exposure cylinder) and the original image are laminated and attached to the exposure cylinder in this order, and the imagewise exposed laminate is obtained. Alternatively, the image forming material is introduced into the nip formed by the exposure cylinder and the transfer cylinder by the rotation of the exposure cylinder, the protective film is removed between the nip or on the surface of the transfer cylinder, and then the image of the image formed on the image forming material is formed. It is an image forming method in which transfer to a receiver is carried out by introducing it into a nip formed by a common impression cylinder holding an image receptor and a transfer cylinder.

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

The original image used in the present invention is a color-separated image mask, but it is also possible to obtain a single-color prepress proof or printed matter, and in that case, a film (image mask) made for single color or a function such as color coding An image mask is used in which light-shielding paper is fixed to a transparent polyethylene terephthalate film having a certain thickness.

The image-forming material used in the present invention 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 polyethylene terephthalate film or sheet is preferable because it is excellent in transparency, heat stability and dimensional stability.

These holders may be used as they are, or may be subjected to a mold 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 film thickness of the photosensitive phase 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.

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

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

This photosensitive layer liquid was applied to a biaxially stretched polyethylene terephthalate film (film thickness 12 μm) so that the dry coating film would be 2.4 μm, and then a polyethylene film (protective film) was attached to the coated surface to form a laminate. Obtained.

Then, instead of carbon black of the photosensitive layer liquid, using the lionol yellow FG1310, Carmine 7BFG4412, lionol blue FG7330, to prepare each photosensitive layer liquid, to obtain a laminate in the same manner as above. .

Using these laminates, in the device shown in FIG.
An image forming material and a color-separated positive film corresponding to each color were attached to each exposure cylinder, and art paper was held on a common impression cylinder, and exposure and transfer were performed in the order of black, cyan, magenta, and yellow. After exposure, the positive film was peeled off on the exposure cylinder. The separation of the protective film from the image forming material was performed between the nip formed by the exposure cylinder and the transfer cylinder. The obtained transfer image was clear.

The feeding speed of the image forming material and the 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.

[Effects 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, especially in a surprint method using a printing paper.

The present invention can be applied not only to the overlay method, but also to small number printing up to several hundreds of copies.

According to the present invention, the quality of the transferred image obtained is good, a normal image can be obtained by one transfer, exposure-transfer (further, post-exposure) can be continuously carried out, and registration is easy. Therefore, a remarkable hardening is achieved in which a stable image can be obtained without depending on the experience and intuition of a skilled person.

Compared with a support of an image-forming material comprising a support and a photosensitive layer, the protective film is thicker and the light transmittance is often inferior.

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, the transfer cylinder and the exposure cylinder are arranged around the common impression cylinder, or the exposure cylinder formed of the light transmissive material is arranged, and the respective colors are transferred almost at the same time, so that the registration is relatively easy, For this reason, it is possible to provide a color proof or printed matter without misregistration.

[Brief description of drawings]

FIG. 1 is a schematic side view of an image forming apparatus of the present invention, FIG. 2 is a side view showing a gripper changing mechanism between an exposure cylinder and a transfer cylinder, and FIGS. 3 and 4 are images. It is a side view which shows the state which put the half cut in the edge part of the protective film of a forming material. 1 ... UV lamp, 3 ... exposure cylinder 5 ... protective film, 7 ... image forming material 11 ... original image, 15 ... transfer cylinder 16 ... common impression cylinder, 21 ... image receptor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-135945 (JP, A) JP-A-62-14650 (JP, A) JP-A-62-246064 (JP, A) JP-A-1- 172957 (JP, A) JP-A-2-15264 (JP, A)

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 a common impression cylinder having image receptor holding means, and an imaging material attachment means contacting at least two of the common impression cylinders radially outside the common impression cylinder. A transfer cylinder having the same, and an exposure cylinder having an image forming material adhering means in contact with the transfer cylinder on the outer side in the radial direction of the transfer cylinder,
An image forming apparatus comprising: at least two light sources for exposing an image forming material, which are arranged on an outer side in a radial direction of the exposure cylinder. 2. The apparatus according to claim 1, wherein the image forming material having a protective film on the exposure cylinder and the original image are laminated and attached in this order, and the imagewise exposed laminate or the image forming material is exposed by rotating the exposure cylinder. The protective film is introduced between the nip formed by the cylinder and the transfer cylinder, the protective film is removed between the nip or on the surface of the transfer cylinder, and then the transfer of the image formed on the image forming material to the image receptor is performed. An image forming method, which is performed by introducing the nip formed by the held common impression cylinder and the transfer cylinder.