JPH03234593A - Image formation - Google Patents

Abstract

PURPOSE:To form an image of high quality free from void or blemish by performing the transfer of a receiving layer two or more times. CONSTITUTION:The transfer of a receiving layer is performed on the same region two or more times. Therefore, the transferred receiving layer can be made thick and, even when a material to be transferred is rough, a non-transfer part can be eliminated. By this method, an image of high quality free from void or blemish is formed. Further, the amount of a transfer dye can be increased by performing the transfer of a dye on the transferred receiving layer two or more times and the transferred dye sufficiently develops a color because of the thick receiving layer and a sharp image having high density and depth is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming method, and more particularly to a method of forming high quality and high density images by a thermal transfer method.

(Prior art and its problems) Conventionally, various thermal transfer methods are known, but among them, a thermal transfer sheet is created by using a sublimable dye as a recording agent and supporting it on a base sheet such as paper or plastic film. There have been proposed methods for forming various full-color images on transfer materials such as paper and plastic films provided with dye-receiving layers. In this case, the thermal head of the printer is used as a heating means, and by extremely short heating, 3
A large number of color dots of one color or four colors are transferred to a transfer material, and a full-color image of an original is reproduced using the multicolor color dots.

The images formed in this way are very clear because the coloring material used is dye, and they have excellent transparency, so the images obtained have excellent intermediate color reproducibility and gradation, and are It is possible to form high-quality images that are similar to images produced by offset printing or gravure printing, and comparable to full-color photographic images.

However, the transfer materials on which images can be formed using the above method are limited to plastic sheets that can be dyed or paper that has a dye-receiving layer in advance, and images cannot be directly formed on general plain paper. The problem is that there is no. Of course, it is possible to form images on ordinary plain paper if a receptive layer is formed on its surface, but this is expensive in terms of shooting. It is difficult to apply this method to general ready-made transfer materials such as report paper.

As a way to solve these problems, when trying to form an image on a ready-made transfer material such as plain paper, a receptor layer transfer sheet is used as a method to easily form a dye receptor layer only in the necessary areas. is known (for example, JP-A-62-
(See Publication No. 264994).

However, when using the above-mentioned receptor layer transfer sheet, it is not possible to make the receptor layer to be transferred very thick, and therefore, not much dye can be transferred to the transfer receptor layer, resulting in a high density image. Cannot be formed. Also, for the same reason, if the transfer material is coarse plain paper, etc., the receiving layer may not be transferred uniformly, and similarly, white spots or chips may occur in the formed image. , the image cannot be of high quality. Furthermore, since the receiving layer is thin, the color development of the transfer dye is also insufficient, resulting in the problem that a deep and clear image cannot be formed.

It is thought that these problems will not occur if the receptive layer is made thicker, but in reality, if the receptive layer is made thicker, it becomes difficult to transfer the receptive layer itself, which does not solve the above problems.

Therefore, an object of the present invention is to provide an image forming method that can apply a dye-receiving layer only to necessary locations of an arbitrary transfer material and can form a high-quality and high-density image.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention uses a receptor layer transfer sheet in which a dye receptor layer is removably provided on one side of a base sheet to transfer the receptor layer to a transfer material, and further transfers the receptor layer from the dye transfer sheet to the receptor layer. In a method of forming a dye image by transferring dye,
This image forming method is characterized in that the above-mentioned receiving layer is transferred to the same area multiple times.

(Function) By performing the transfer of the receiving layer multiple times, the thickness of the transferred receiving layer can be increased, and even if the material to be transferred has a rough texture, it is possible to eliminate untransferred portions. A high-quality image with no white spots or chips is formed.

Also, in preferred embodiments, the amount of transferred dye can be increased by performing multiple transfers of dye to the transfer-receiving layer. Since the transferred dye has a thick receiving layer, the color develops sufficiently, resulting in a clear image with high density and depth.

Furthermore, since the initially transferred dye is heated again, the color development is even better, resulting in a clearer image.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The receptor layer transfer sheet used in the present invention is one in which a dye receptor layer is releasably provided on one side of a base sheet.

As the base material sheet used, the same base material sheet used for conventional thermal transfer sheets can be used as is, and other materials can also be used.
There are no particular restrictions.

Specific examples of preferred base sheets include thin paper such as glassine paper, capacitor paper, and paraffin paper, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, and polyvinylidene chloride. , plastics such as ionomers, and base sheets made of composites of these and the above-mentioned paper.

The thickness of this base sheet can be changed as appropriate depending on the material so that its strength, heat resistance, etc. are appropriate, but the thickness is preferably 3 to 100 μm.

It is preferable to form a release layer on the surface of the base sheet prior to forming the receptor layer. Such a release layer is formed from a release agent such as wax, silicone wax, silicone resin, fluororesin, or acrylic resin. The formation method may be the same as the method for forming the receptor layer described later, and a thickness of about 0.5 to 5 μm is sufficient. If a matte receiving layer is desired after transfer, the surface can be made matte by incorporating various particles into the release layer or by using a base sheet whose surface on the release layer side has been matt treated. Of course, if the base sheet as described above has appropriate releasability, it is not necessary to form a release layer.

The dye-receiving layer formed on the surface of the above-mentioned base sheet is for receiving the sublimable dye that migrates from the thermal transfer sheet after transferring the receptor layer to an arbitrary transfer material and maintaining the formed image. It is.

Examples of the resin for forming the dye-receiving layer include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylic ester,
Polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, polycarbonates Among them, vinyl resins and polyester resins are particularly preferred.

Preferred mold release agents to be mixed with the above resin include:
Examples include silicone oil, phosphate ester surfactants, fluorine surfactants, etc., but silicone oil is preferable.
Modified silicone oils such as alkyl-modified, amino-modified, carboxyl-modified, alcohol-modified, fluorine-modified, alkylaralkyl polyether-modified, epoxy/polyether-modified, and polyether-modified silicone oils are desirable.

One or more types of mold release agents may be used. The amount of the release agent added is preferably 0.5 to 30 parts by weight per 100 parts by weight of the dye-receiving layer forming resin. If the addition amount does not fall within this range, problems such as fusion between the thermal transfer sheet and the dye-receiving layer or a decrease in printing sensitivity may occur. By adding such a release agent to the dye-receiving layer, the release agent bleeds out to the surface of the dye-receiving layer after transfer, forming a release layer.

The receiving layer is prepared by dissolving the above-mentioned resin with necessary additives such as a mold release agent on one side of the base sheet in an appropriate organic solvent or dispersing it in an organic solvent or water. The obtained dispersion can be processed, for example, by gravure printing method, screen printing method,
It is formed by coating and drying by a forming means such as a reverse roll coating method using a gravure plate.

When forming the dye-receiving layer, titanium oxide, zinc oxide,
Pigments and fillers such as kaolin clay, calcium carbonate, and finely powdered silica can be added.

The dye-receiving layer formed as described above may have any thickness, but the thickness is from 1 to 50 .mu.m in terms of radiation. Although such a dye-receiving layer is preferably a continuous coating, it may also be formed as a discontinuous coating using a resin emulsion or resin dispersion.

Furthermore, an adhesive layer may be provided on the surface of the above-mentioned receptor layer in order to improve the transferability of these layers. These adhesive layers are made of, for example, polyamide resin, acrylic resin,
Vinyl chloride resin, vinyl chloride/vinyl acetate copolymer resin,
Such as polyester resin (preferably 0.5
It is formed to a thickness of about 10 μm.

The material to which the receptor layer is transferred using the receptor layer transfer sheet as described above is not particularly limited, and examples include plain paper,
It can be any sheet such as high-quality paper, tracing paper, plastic film, etc. (Also, in terms of shape, it can be any sheet such as cards, postcards, passports, stationery, report paper, notebooks, catalogs, etc., especially those with rough surfaces. It can also be applied to plain paper and rough paper.

The receiving layer can be transferred using any heating method that can be heated to a temperature that activates the receiving layer or adhesive layer, such as a general printer equipped with a thermal head for thermal transfer, a hot stamper 1 heat roll for transfer foil, etc. A pressurizing means may also be used.

The thermal transfer sheet used in the present invention is formed by forming a dye layer on a base sheet as in the prior art.

The base sheet of the thermal transfer sheet as described above is the same as the base sheet of the receptor layer transfer sheet, and the dye layer formed on the surface of the base sheet is a layer in which a dye is supported by an arbitrary binder resin. .

The dye to be used is not particularly limited, as any dye used in conventionally known thermal transfer sheets can be effectively used in the present invention. For example, some preferred dyes include MS Red G, Mac
rolex Red Violet R, CeresR
ed7B, Samaron Red HBSL, Re
Examples of yellow dyes include Holon Brilliant Yellow 6GL,
PTY-52, Macrolex Yellow 6G, etc., and blue dyes include Kaya Set Blue 14,
Examples include Vaxolin Blue AP-FW, Holon Brilliant Blue SR, MS Blue 100, and the like.

As the binder resin for supporting the above-described dye, any conventionally known binder resin can be used, and preferred examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate,
Examples include cellulose resins such as cellulose acetate butyrate, vinyl resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acecool, polyvinyl pyrrolidone, polyacrylamide, and polyester. Among these, cellulose resins, acetal From the viewpoint of heat resistance, dye migration properties, etc., polyester-based dyes, butyral-based dyes, butyral-based dyes, and polyester-based dyes are preferred.

Furthermore, the dye layer may also contain various other conventionally known additives as required.

Preferably, such a dye layer is prepared by adding the above-mentioned sublimable dye, binder resin, and other optional components in a suitable solvent, dissolving or dispersing each component, and preparing a paint or ink for forming the dye layer. It is formed by coating and drying on the above base sheet.

The dye layer formed in this way has a thickness of about 0.2 to 5.0 μm, preferably about 0.4 to 2.0 μm, and the sublimable dye in the dye layer has a thickness of about 5 to 5.0 μm. ~90% by weight
, preferably in an amount of 10 to 70% by weight.

When the desired image is a monochrome image, the dye layer to be formed is formed by selecting one color from among the dyes mentioned above, and when the desired image is a full color image, it is formed by selecting an appropriate dye layer such as cyan, magenta, and the like. Select yellow (and black if necessary) to form yellow, magenta, and cyan (further black if necessary) dye layers.

Any conventionally known means for applying thermal energy can be used to apply thermal energy when performing thermal transfer using the above-mentioned thermal transfer sheet and the transfer material to which the receptor layer has been transferred, such as a thermal printer. (For example, by controlling the recording time using a recording device such as Hitachi Video Printer VY-100)
0mJ/mtr? By applying a certain amount of thermal energy, the desired image is formed.

An important feature of the present invention is that the same pattern is transferred to the same location at least twice on the receiving layer using the receiving layer transfer sheet, and the dye is also transferred at least twice (both times).

Examples of multiple transfer methods include: (1) a method in which the receiving layer is transferred to the same location on the transfer material two or more times in succession, and then a dye is transferred thereon two or more times in succession; There is a method of transferring a receptor layer to a transfer material, then successively transferring a dye onto it, and then repeating the same operation on the same area, but in either case, the color is high density and clear, and also Deep, high-density images are easily formed.

Furthermore, by transferring the receiving layer last, this final receiving layer can act as a surface protective layer, thereby improving various durability of the image.

(Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. In the text, parts or percentages are based on weight unless otherwise specified.

Example 1 A receptor layer coating solution having the following composition was applied to the surface of a 25 μm thick polyester film (trade name "Lumirror", manufactured by Toshi ■) using a bar coater at a dry rate of 5.0 g/rrr. After applying and temporarily drying with a dryer, dry in an oven at 100°C for 30 minutes to form a dye-receiving layer, and then apply the following adhesive solution on the receptor layer in the same manner and apply 2g1r when drying.
An adhesive layer was formed by coating and drying at a ratio of d to obtain a receptor layer transfer sheet of the present invention.

91゛Eng゜; Polymethyl methacrylate resin (manufactured by Mitsubishi Rayon ■, B
R-85PMMA) 100 parts amino-modified silicone (X-22-343, Shin-Etsu Chemical Co., Ltd.
5-part epoxy-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.)
5 parts Methyl ethyl ketone/toluene (weight ratio l/1) 500 parts Ethylene-vinyl acetate copolymer heat sealant (manufactured by Toyo Morton ■, AD-37P295) 100 parts Pure water 100 parts On the other hand, a dye having the following composition A layer ink was prepared and applied to a 6 μm thick polyethylene terephthalate film whose back surface had been heat-resistant treated, with a dry coating amount of 1. Apply and dry with a wire bar so that it becomes Og/A, and then apply silicone oil (X-4) on the back.
A few drops of 1.4003A (manufactured by Shin-Etsu Silicone ■) were added using a dropper, and the mixture was spread over the entire surface to provide a backside treatment coat to obtain a thermal transfer sheet.

Tosha 1ri Ezara Kai: Disperse dye (Kaya Set Blue 14, manufactured by Nippon Kayaku ■)
4.0 parts Ethyl hydroxycellulose (manufactured by Vercules) 5.0 parts Methyl ethyl ketone/toluene (weight ratio 1/1180.
0 parts Dioxane 10.0 parts Similarly, a yellow thermal transfer sheet was coated with yellow disperse dye (M
acrolex Yellow 6G, manufactured by Bayer,
C, 1, Disperse Yellow 201)
and magenta thermal transfer sheet with magenta disperse dye (C,I).

Disperse Red60).

The above-mentioned receptor layer transfer sheet and plain paper are superimposed, and a thermal head is used to set an output of 1W/dot and a pulse width of 0.
:3-0.45m5ec, dot density 3 dots/m
Printing was carried out under the conditions of m to transfer the patterned receptor layer, and then the thermal transfer sheet was placed on the surface of the receptor layer to form a cyan image under the same conditions. Further, the receiving layer and the dye were each transferred once in the same pattern under the same conditions onto the surface of the image obtained above to obtain an image.

Note that yellow and magenta images were also formed in the same manner.

Example 2 In Example 1, the receiving layer was first transferred twice, and then the dye was transferred once in the same manner as in Example 1 to form yellow, cyan, and magenta images, respectively.

Example 3 In Example 1, the receiving layer was dyed three times each.

Comparative Example 1 In Example 1, the receiving layer and dye were transferred once each.

The density and quality of each color image obtained above are shown in Table 1 below.

Also, in a preferred embodiment, the amount of transferred dye can be increased by performing multiple transfers of dye to the transfer-receiving layer. Since the transferred dye has a thick receiving layer, the color develops sufficiently, resulting in a clear image with high density and depth.

Furthermore, since the initially transferred dye is heated again, the color development is even better, resulting in a clearer image.

0: Good color development and clarity, with no omissions or chips observed.

×: Missing or chipping is observed.

(Effects) According to the present invention as described above, by performing the transfer of the receiving layer multiple times, it is possible to thicken the transfer receiving layer, and even if the material to be transferred has a rough texture, the untransferred portions can be removed. Therefore, high-quality images without white spots or chips can be formed.

Claims (2)

[Claims] (1) Transfer the receptor layer to a transfer material using a receptor layer transfer sheet that has a removable dye receptor layer on one side of a base sheet, and then transfer the dye from the dye transfer sheet to the receptor layer. An image forming method for forming a dye image by transferring the receiving layer to the same area a plurality of times. (2) The image forming method according to claim 1, wherein the dye is transferred to the transfer-receiving layer multiple times.