JPH01127376A - Patterned heating method - Google Patents

Abstract

PURPOSE:To obtain printing characters or images which are as superior in resolving power and reproducibility as an offset printing or gravure printing without the need for a mechanical heating method, by a method wherein a patterned light-transmitting body, a photothermo-conversion body, and a material to be heated are laid over each other, and light is directed through the light-transmitting body. CONSTITUTION:A patterned light-transmitting body 1, a photothermo-conversion body 2, and a thermally coloring recording medium 3 serving as a material to be heated are laid over each other, and a light irradiation 6 is applied through the light- transmitting body 1, whereby an image 4 corresponding to the pattern of the light- transmitting body is formed by coloring on the recording medium 3. As the patterned light-transmitting body 1 in use, all materials obtained by patterning a light- transmitting part and a light-interrupting part on a transparent material, such as a glass plate and a plastic film or sheet, are available: a negative image or positive image of a photographic film is preferably used. Alternatively, a negative or positive image obtained by the halftone color separation of a full-color original is preferably used. In addition, as a light source in use, all of an ultraviolet light source, a visible light source, an infrared light source, or the mixed light source of these are available.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for heating a pattern, and more specifically, a method for heating a large number of objects without the need for mechanical heating means such as a thermal head. The present invention relates to a novel pattern heating method that allows heating.

(Prior Art) Conventionally, as a method of heating the surface of an object in a pattern, a thermosensitive color recording method using a thermal head and a thermal transfer method are known. The thermosensitive color recording method is a method in which the surface of a recording medium containing a material that develops color when heated is heated with a thermal head to develop color and form an image.The thermal transfer method forms a colored transfer layer on a base film, and the back side To form characters and IA shadows, images such as patterns are heated in the form of images using a thermal head, and the E color transfer layer is thermally transferred onto the surface of the transfer material.

To further explain the thermal transfer method as a representative example, this method is roughly divided into two types, a wax type and a multiplication transfer type, depending on the structure of the colored transfer layer.

The wax type uses a thermal transfer sheet with a colored transfer layer formed on a base film that can be easily softened and transferred by heating, and transfers the colored wax layer to the transfer material. In the transfer type, a dye that sublimes or migrates when heated is supported on the base film using a suitable binder, and by heating from the back side, only the dye in the dye layer is thermally transferred to the surface of the transfer material to form an image. It is something to do.

Both methods are capable of forming monochrome and multicolor images, and in the case of multicolor images, three or four color thermal transfer sheets are available, for example yellow, magenta, cyan, and black if necessary. Then, each color is aligned on the surface of the same transfer material and thermal transfer is performed to reproduce a color image.

In any case, a thermal head is used as the first stage of heating.

(Problem to be Solved by the Invention) The above thermal transfer method has been developed as a simple pattern heating method to replace printing methods that are expensive and require large stepped teeth, such as offset printing and gravure printing, which have been practiced for a long time. However, using a thermal head as a heating means has the following drawbacks.

(1) For example, since printing is performed line by line, it takes a relatively long time to complete an image.

(2) The size of the heating dot of the thermal head is approximately 50 mm.
The diameter is between 200 .mu.m and it is currently impossible to make it smaller than this, and therefore the dots forming the image are coarse, so the resolution of the image formed cannot be said to be sufficient.

(3) Especially when forming a three- or four-color image, in addition to the disadvantages of (1) and (2) above, it is necessary to return the transfer material to its original position three or four times. Therefore, the consistency of dots of each color is poor, and color reproducibility is insufficient.

Therefore, there is a need for a patterned heating method that, although it is a thermal transfer method, can produce prints and images with excellent resolution and reproducibility like conventional offset printing or gravure printing without requiring mechanical heating means such as a thermal head. has been done.

(Means for Solving the Problems) The present inventor completed the present invention as a result of intensive research in order to meet the demands of the prior art as described above.

That is, the present invention is a patterned heating method characterized in that a patterned light transmitting body, a light-to-heat converting body, and an object to be heated are idle, and light is irradiated through the light transmitting body.

(Function) The light image formed by passing through the patterned light transmitting body is turned into a thermal image by the light-to-heat converter, and by heating the object to be heated with this thermal image, mechanical means such as a thermal head can be used. The object to be heated can be heated in an arbitrary pattern without using it.

(Preferred Embodiments) The present invention will now be described in more detail with reference to the accompanying drawings, which schematically show preferred embodiments of the invention.

FIG. 1 shows an example in which the method of the present invention is applied to a printing or image forming method on a thermosensitive color recording medium.

In this example, a patterned light transmitting body 1, a light-to-heat converting body 2, and a thermosensitive color-forming recording medium 3, which is a heated object, are stacked and light is irradiated (arrow 6) through the light transmitting body 1. An image 4 is colored and formed on the recording medium 3 in accordance with the pattern of the light transmitting body. Of course, in this example, if the recording medium has the property of decolorizing with heat, a blank image will be formed.

FIG. 2 shows an example in which the method of the present invention is applied to a printing or image forming method using a thermal transfer sheet.

In this example, a patterned light transmitting body 1, a light-heat converting body 2,
By overlapping the thermal transfer sheet 20, which is an object to be heated, and the transfer material 5, and irradiating light (arrow 6) through the light transmitting body 1, the transfer layer 7 of the thermal transfer sheet 20 is transferred to the transfer material 5, and the transfer layer 7 is transferred to the transfer material 5. An image 8 is formed according to the pattern of the transparent body.

Patterned light transmitting body 1 used in the above method
may be a transparent object such as a glass plate, a plastic film, or a sheet with light-transmitting areas and light-blocking areas formed in a pattern, and is not particularly limited, but suitable examples include negative images and positive images of photographic film. Examples include images, and negative and positive images obtained by halftone color separation of full color 1g and M are preferably used. Of course, the pattern is not limited to black and white.
It is also possible to use a material in which the light-opaque portion is vapor-deposited with metal to make it light-reflective.

Further, the light source used can be an ultraviolet light source, a visible light source, an infrared light source, or a mixture of these light sources, such as a general xenon lamp used in the plate-making process,
Incandescent lamps, infrared lamps, mercury lamps, lasers, etc. can be used as is. Further, although the light irradiation time cannot be absolutely defined depending on the type of light source, etc., it is possible to complete the light irradiation in a short time of usually 0.0001 to 10 seconds, preferably 0.001 to 10 seconds. It should be noted that the shorter the irradiation time, the more faithfully the original can be represented in image formation.

As shown in FIG. 1, the light-to-heat converter 2 used in the present invention is a sheet or film colored black or dark in color, preferably a colored plastic sheet, and other examples include A black or dark-colored light-to-heat conversion layer 10 is formed on one or both sides of the base film 9 (FIG. 3), and a more preferable example is as shown in FIG. Light-heat conversion layer 1 made of softening point material
0 and further includes a heat-resistant layer 11 formed on the surface thereof. The light-to-heat converter 2 as described above may be provided directly on the surface of the object to be heated if there is no particular problem.

The light-to-heat converter 2 shown in the first diagram needs to be black or dark-colored and light-absorbing, such as black or dark-colored polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polychloride. There are plastic films such as vinyl, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, and ionomers, papers such as condenser paper and paraffin paper, and nonwoven fabrics.
Alternatively, a film that is a composite of these may be used.

The thickness of the light-heat converter 2 can be changed as appropriate depending on the material so that its strength and thermal conductivity are appropriate, but the thickness is preferably, for example, 3 to 25 μm.
It is m.

The method of making these colorless films light-absorbing may be any known method. For example, when forming the film, a black pigment such as carbon black, a black dye such as nigrosine dye, etc. is added to the film in an amount of 0.5 to 0.5 to 0. It can be obtained by incorporating the film at a concentration of about 30%, or by dyeing it with a black dye such as a disperse dye after forming a film.

Further, the example shown in the third figure is one in which a black or dark-colored layer 10 is formed on one or both sides of various plastic films 9 (films such as those mentioned above that are not light-absorbing) using black or dark-colored paint or ink. Any conventionally known black or dark-colored paint or ink can be used.

The thickness of these light-heat conversion layers 10 is not particularly limited, but is generally about 1 to 50 μm, for example.

In a particularly preferred embodiment, the light-to-heat conversion layer 10 is formed from a low-softening point material such as wax or a low-melting-point resin. - These layers are preferably melted or softened during heat conversion and the light-to-heat conversion efficiency is significantly improved.

Furthermore, in the example shown in FIG. 4, in the case of the preferred embodiment shown in FIG.
For example, this is an example in which a heat-resistant layer 11 is formed on the surface of the light-to-heat conversion layer 100 in order to prevent it from sticking to the patterned light transmitting body 1 or the object to be heated 3.

This heat-resistant layer 11 may be formed by laminating various kinds of plastic films as described above, or may be formed by a coating method using a paint or ink containing a binder having a relatively high softening point, for example, the binder described below.

These heat-resistant layers 11 are preferably thinner in terms of thermal conductivity, and typically have a thickness of about 0.5 to 10 μm, for example.

The light-heat conversion layer 10 is formed from a binder and a black or dark coloring material, and the low softening point binder is mainly composed of wax, and other materials such as wax, drying oil, resin, mineral oil, cellulose, and rubber derivatives. A mixture of

As black or dark coloring agents, carbon black,
Black pigments such as aniline black and iron black, and black dyes such as nigrosine are preferably used.

These colorants in the light-to-heat conversion layer are used in a concentration of, for example, about 0.5 to 30% by weight.

Representative examples of wax include microcrystalline wax, carnauba wax, paraffin wax, and the like. Furthermore, various waxes such as Fischer-Tropsch wax, various low molecular weight polyethylenes, wood wax, beeswax, spermaceti wax, privet wax, wool wax, shellac wax, candelilla wax, petrolatum, partially modified wax, fatty acid ester, fatty acid amide, etc. are used. It will be done.

Further, as the binder used for forming the light-heat conversion layer 10 and the heat-resistant layer, which do not have a low softening point, any conventionally known binder can be used, and preferred examples include:
Cellulose resins such as ethyl cellulose, droxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, polyacrylamide, etc. Vinyl resin, polyester, etc. are preferred.

Methods for directly or indirectly forming the colored layer 10 and heat-resistant layer 11 on the base film 9 include hot melt coating, lamination, hot lacquer coating, gravure coating, gravure reverse coating, roll coating, and many other methods. Examples include methods.

Next, a method of forming a color image using a known thermal transfer sheet 20 according to the method of the present invention will be explained with reference to FIG.

The thermal transfer sheet 2o used has a heat-melting colored ink layer 7 on one side of a base film 12 that is softened by heat and is peeled off to form an image (a so-called wax type), and a base film 12. ! There are known dye layers 7 containing a so-called sublimable dye that sublimes with heat on one side of the dye layer 7 (so-called sublimation type), and any of them can be used.

In the case of a wax-type thermal transfer sheet, the transfer material 5 used to form an image using the thermal transfer sheet 20 as described above is a general paper such as plain paper, high-quality paper, synthetic paper, or mixed paper. In the case of sublimation transfer type, the transfer surface to be dyed with the dye, such as a plastic sheet with dye receptivity, paper with a dye receptive layer, etc., may be used, but is not particularly limited. It is necessary that the material has the following properties.

For the thermal transfer sheet 20 as described above, at least three colors of cyan, magenta and yellow are prepared, and if necessary, black is added to increase the four colors. It goes without saying that these thermal transfer sheets may be sheet-fed as described above, or they may be continuous sheets in which each color is painted separately α on the same continuous base film in a field-sequential or line-sequential manner.

As shown in the second diagram, cyan, magenta, yellow, and, if necessary, black patterned light-transmitting bodies 1 obtained by color-separating the original are separated, and these patterned light-transmitting bodies 1 are separated.
is placed on the back side of the corresponding colored area on the thermal transfer sheet 20 of the corresponding color or in succession with the light-to-heat converter 2 interposed therebetween. This stacked layer is further stacked with the ink layer 7 facing the transfer material 5, and in this state, light irradiation (ultraviolet light, visible light, infrared light, etc.) (arrow) is performed through the patterned light transmitting body 1. The light is transmitted through the black part (
In contrast, the light does not reach the light-to-heat converter 2 in the transparent part (or the image part) (non-image part).
This heat reaches the ink layer 7 and softens the ink layer 7, and the softened ink layer 7 is transferred to the transfer material 5F to form a positive image 8.

By repeating the above operation once for each color on the same transfer material 5, a three-color or four-color image is formed and a color image is reproduced.

In addition, when carrying out the above method, the light-heat converter 2
The light-heat converter 2 is used to transfer heat to the colored transfer layer.
It is preferable that at least the thermal transfer sheet and the material to be transferred, preferably the three of them, be sufficiently brought into close contact with each other using a vacuum so that the thermal transfer sheet 20 and the material to be transferred 5 are brought into close contact with each other as much as possible.

The above example is an example using a wax type thermal transfer sheet, and with the sublimation transfer type, only the sublimation dye in the colored transfer layer 7 transfers to the transfer material to form an image. It is similar to

Furthermore, when the method of the present invention is applied to the heat-sensitive color recording medium shown in FIG. 4 is formed.

(Effects) According to the present invention as described above, an image with high resolution and excellent color reproducibility can be easily and quickly formed without using a thermal head during image formation.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the text, parts or percentages are based on weight unless otherwise specified.

Example 1 Using a polyester coloring masterbatch with a carbon black concentration of 40%, the thickness was 5 μm by the stock solution coloring method.
black polyester film (carbon black concentration 1
0%) was formed into a film to form a light-to-heat converter.

On the other hand, a Fuchs type thermal transfer sheet (manufactured by Dai Nippon Printing Co., Ltd.) having successive yellow, cyan, magenta, and black ink layers in one section was prepared.

Next, we prepared negative films for four colors formed by separating a full-color photographic original into halftone colors for offset printing, and high-quality paper as a transfer material.

Yellow patterned light transmitting body 1, light-heat converting body 2,
The yellow thermal transfer sheet 20 and the transfer material 5 were stacked in the order described above and brought into close contact under vacuum, and flash exposure was performed from the light transmitting body side using a xenon lamp. When the transfer material was peeled off, a yellow image 8 was formed. Ta.

Magenta, cyan, and black were similarly transferred to the transfer material having the yellow image 8 in the same manner as described above to obtain a full-color image. This full-color image had excellent resolution and faithfully reproduced the colors of the original.

Example 2 Ink A having the following composition was coated on one surface of a 5 μm polyester film of J7 so as to have a dry thickness of 5 μm and dried to form a light-to-heat conversion layer to obtain a light-to-heat converter. Ta.

Elle A Carbon Black (Dia Black G, manufactured by Mitsubishi Kasei)
3 parts ethylene/vinyl acetate copolymer (EV^flex 31O1 Mitsui Polychemicals%) 'to part methyl ethyl ketone
60 copies On the other hand, a sublimation transfer type thermal transfer sheet (manufactured by Dainippon Printing Co., Ltd.) having yellow, cyan, magenta, and black ink layers successively in one section was prepared.

Next, a full-color photographic original was subjected to halftone color separation for offset printing using negative film for four colors and special paper (manufactured by Dai Nippon Printing Co., Ltd.) as a transfer material.

Yellow patterned light transmitting body 1, light-heat converting body 2,
The yellow thermal transfer sheet 20 and the transfer material 5 were adhered in vacuum in the order described above, exposed to flash from a xenon lamp from the light-transmitting body side, and the transfer material was peeled off, resulting in a yellow image 8. Been formed.

Magenta, cyan, and black were similarly transferred to the transfer material having the yellow image 8 in the same manner as described above to obtain a full-color image. This full-color image had excellent resolution and faithfully reproduced the colors of the original.

Example 3 Instead of the light-heat conversion layer formed in Example 2, the following ink B was applied to a thickness of 8 μm, and a transparent polyester film with a thickness of 3.5 μm was laminated on the surface to form the heat-resistant layer 11. A light-to-heat conversion sheet was prepared, and a color image with excellent resolution was obtained in the same manner as in Example 1.

Elma 1 Carbon Black (Diablack G1 manufactured by Sanyi Kasei)
3 parts ethylene/vinyl acetate copolymer (EV＾flex 31O1 manufactured by Mitsui Polychemicals) 1 part butterfin wax (paraffin 15
0F, manufactured by Nikki Seiro) 10 parts Example 4 On the surface of the light-heat conversion layer 10 formed in Example 3,
When drying a 20% solution of polyvinyl butyral, the film thickness is 2μ.
A transparent heat-resistant layer 11 was formed by coating and drying to give a light-to-heat conversion sheet, and the same procedure as in Example 1 was carried out to obtain a color image with excellent resolution.

[Brief explanation of the drawing]

1 and 2 are views schematically showing the method of the present invention, and FIGS. 3 and 4 are views schematically showing a cross section of a light-to-heat converting Buddhist painting. 1: Patterned light transmitting body 2: Light-heat conversion body 3: Heated body 4: Image 5: Transferred material 6: Light 7: Ink layer 8: Yellow image 9: Base film 10: Light-heat conversion layer 11 :゛Heat-resistant layer 122 Base film 20: Under thermal transfer sheet Patent applicant Dainippon Printing Co., Ltd. Agent Patent attorney Furu 1) Katsuhiro Figure 1 Figure 2 Figure 3 Figure 4

Claims (6)

[Claims] (1) A patterned heating method characterized by stacking a patterned light transmitting body, a light-heat converting body, and an object to be heated, and irradiating light through the light transmitting body. (2) The patterned heating method according to claim (1), wherein the light-heat converter is a black or dark colored body. (3) The patterned heating method according to claim (1), wherein the light-heat converter is a colored layer formed on the surface of the object to be heated. (4) The patterned heating method according to claim (1), wherein the light-heat converter is a black film. (5) The patterned heating method according to claim (1), wherein the object to be heated is a thermosensitive color recording medium or a thermal transfer sheet. (6) The patterned heating method according to claim (1), wherein the light-heat converter is made of a material that melts or softens with heat.