JPH01244891A - Image receiving sheet for thermal transfer recording - Google Patents

Abstract

PURPOSE:To obtain a recording image having gloss equivalent to silver chloride photograph even by a normal sublimed thermosensitive transfer printer by providing an image receiving layer made of ultraviolet ray curable resin on a base. CONSTITUTION:As a base 1, synthetic sheet, sheets or plastic film or the like is employed. An image receiving layer 2 as a main part is formed of ultraviolet ray curable resin. As the resin, the resin which has high dyeing property, suitable heat resistance, is not fusion-bonded to a transfer film, and curing speed of a practical range by normal ultraviolet ray irradiation, is selected. As the resin, oligoacrylate is employed. More particularly, oligomer selected from a group consisting of polyolacrylate, polyesteracrylate, epoxy acrylate, urethane acrylate, etc. is employed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an image receiving paper for thermal transfer recording, and in particular to a thermal transfer sheet coated with a heat-sublimable coloring material used in a heat-sublimation type heat-sensitive transfer recording device. The present invention relates to an image-receiving paper for thermal transfer recording, onto which a coloring material of a sheet is transferred by heating.

2. Description of the Related Art In recent years, various color image reproducing devices such as home video and computer graphics have been mentioned, and recording devices (hereinafter referred to as "printers") for printing out these reproduced images have been developed. These printers include, for example, inkjet printers, electrophotographic printers, thermal transfer printers, etc. Among these printers, thermal transfer printers have a relatively simple mechanism and are easy to handle. Its features include low noise and the ability to obtain color images with good gradation. These thermal transfer printers include a sublimation type thermal transfer method (sublimation type) that uses a heat-sublimable dye as a coloring material, and a melt-type thermal transfer method that uses a heat-melting binder and a pigment as a coloring material. (melted type).

The principle of printing by a thermal transfer printer is as shown in FIG. The image receiving layer 7 is provided on the substrate 6 (fourth layer).
(B)) are superimposed so that the image-receiving layer 7 of the image-receiving paper and the ink layer 4 of the transfer sheet face each other, and then, for example, use a thermal head of a printer to (b) The color material in the ink layer 4 of the transfer sheet is transferred to the image receiving layer 7 of the image receiving paper by further heating. This receiving layer 7 is made of, for example, a thermoplastic resin having a dye-staining property, and is obtained by coating the thermoplastic resin on the substrate 6 and drying it.

By the way, when comparing the above-mentioned flower type and melt type thermal transfer methods, it is said that the sublimation type is numerically inferior to the melt type in terms of storage stability, sensitivity, and gloss of the recorded image surface. However, the R-flower type thermal transfer method has the great advantage of being able to obtain high-quality recorded images with higher resolution than the fusion type, and the development of applications for dye-sublimation printers is aimed at maximizing this feature. is progressing to Particularly in recent years, the pixel density of the thermal head has improved, and the trend is towards higher quality.

In addition, the substrate of image-receiving paper has traditionally been designed with Bekk smoothness (
According to Japanese Industrial Standards p-811G) is 500 to 150
Synthetic paper is often used.

Problems to be Solved by the Invention However, even though the resolution of dye-sublimation printers has improved, images recorded on conventional image-receiving paper lack gloss because the surface smoothness of the image-receiving layer is low, and there are localized areas where the coloring material is not transferred. The problem was that the image quality deteriorated due to the occurrence of large defects (white spots), and in these respects it was far inferior to color prints made from silver halide photographs.

Several means have been proposed to improve such low gloss recorded images. For example, JP-A-60-23
No. 096 (Japanese Patent Application No. 58-132350, title of the invention: "Cover film for color hard copy photographic paper") discloses a resin on a heat-resistant base material that is melt-transferred to photographic paper and peeled off by heating. A cover film for color hard copy photographic paper (hereinafter simply referred to as cover film) has been proposed, and this seems to be an effective means for imparting gloss even to a recorded image surface with poor smoothness.

However, this means requires the preparation of a cover film provided with a dedicated protective resin layer, completely separate from the transfer sheet. Incorporating a separate dedicated cover film into the printer in this way is not only a major hindrance to the dye-sublimation heat-sensitive transfer method, which is characterized by its simple mechanism, but also increases costs, which is not desirable. Furthermore, even if the cover film transfer mechanism is not incorporated into the printer, a separate dedicated laminator is required, and in any case, there is a drawback that an increase in cost is inevitable.

Also, Japanese Patent Application Laid-open No. 132680/1983 (Japanese Patent Application No. 60-2
No. 73664. The title of the invention [``Method for manufacturing Victorian hard copies''] proposes a method of smoothing and heat-treating the printing surface (recording surface) of image-receiving paper using a heat roller or the like after image recording, thereby producing clear and glossy images. It is said that high-quality recorded images can be obtained. However, in this case as well, a new mechanism is added to a printer with a simple mechanism, and the addition of such a new mechanism is not desirable, as in the above example.

It must be said that all of the methods described above for obtaining silver halide photographic Victorian color images with high gloss have problems.

The present invention has been made in view of the above-mentioned points, and provides an image receiver for thermal transfer recording, which allows recording images having the same level of gloss as silver halide photography to be obtained even with a conventional sublimation type thermal transfer printer. The purpose is to provide paper.

Means for Solving the Problems In order to obtain an image-receiving paper capable of producing a recorded image with high gloss, the inventor of the present application formed an image-receiving layer using various resin materials and found that ultraviolet curing was found. We found that mold resin was the most effective.

The image-receiving paper for thermal transfer recording according to the present invention has an image-receiving layer made of the above-mentioned ultraviolet curable resin on a substrate.

Specifically, an ultraviolet curable resin having a predetermined composition is applied onto a substrate such as synthetic paper, and ultraviolet rays are irradiated to harden the ultraviolet curable resin to form an image-receiving layer.

During functional recording, the image-receiving layer made of an ultraviolet curable resin is brought into close contact with the ink layer of the transfer sheet and pressed appropriately by the thermal head of the printer.

When the heating resistor at a predetermined position of the thermal head is energized and generates heat, the coloring material (dye) in that part of the transfer sheet sublimes and is dyed onto the image-receiving layer, and the coloring material is blown away by the heat and appropriate pressure. The surface of the image-receiving layer dyed with the dye is smoothed and a recorded image with high gloss is obtained.

Embodiment FIG. 1 shows a cross-sectional view of a receiver (g1 paper) according to an embodiment of the present invention, in which 1 is a substrate such as synthetic paper as will be described later, and 2 is a material coated on this substrate 1 as described later. This is an image-receiving layer made of an ultraviolet curable resin.Furthermore, Fig. 2 shows how the coloring material (dye) is thermally transferred from the transfer paper to the image-receiving paper shown in Fig. 1, and in the same figure, 3 indicates the color. It shows the recording layer to which the material has been transferred.

Here, as the substrate 1, synthetic paper, papers, well-known plastic films, etc. are used. As the synthetic paper, for example, a polypropylene resin-based one (Yubonato manufactured by Tamago Yukasei M) can be used, and as the paper, for example, art paper (Super Art manufactured by Yamama Kokusaku Valve) or coated paper can be used. In addition, the plastic film is
A polyethylene terephthalate film or the like can also be used as the substrate 1 when used as a transparency sheet for a head/projector.

As mentioned above, the image receiving layer 2, which is the main part of the present invention, is formed of an ultraviolet curable resin. This UV-curable resin has high color material (dye) dyeability, moderate heat resistance, does not fuse with the transfer film, and can be cured at a practical speed by ordinary UV irradiation. What you have is chosen. Furthermore, since ultraviolet curable resins are highly irritating to the skin, they must be selected with due consideration given to safety. Oligoacrylates are UV-curable resins that meet these conditions, specifically polyol acrylates,
An oligomer selected from the group consisting of polyester acrylate, epoxy acrylate, urethane acrylate, etc. is used.

The initial glossiness of the surface of the image-receiving layer formed by coating the above oligoacrylate on synthetic paper is 100% or more regardless of which oligoacrylate is used (measured with a gloss meter manufactured by Tokyo Denshoku Co., Ltd.).

The same applies hereafter). On the other hand, the gloss level of the surface of the image receiving paper prepared by coating a thermoplastic resin such as a linear saturated polyester resin on a synthetic paper substrate as in the past was about 30%. Furthermore, the glossiness of the surface after transferring the coloring material to the image receiving paper having the oligoacrylate image receiving layer of this example further increased to about 110%. On the other hand, in the case of image-receiving paper having an image-receiving layer made of the linear saturated polyester resin, the gloss decreases from around 30% of the initial state to around 20%, and the gloss is gradually lost.

The ultraviolet curable resin of the receiving layer is prepared by adding trifunctional and trifunctional acrylate monomers as reactive diluents to oligomers selected from the group of polyol acrylates, polyester acrylates, epoxy acrylates, and urethane acrylates. It is also possible to add a photosensitizer to increase the reactivity with ultraviolet light.

Hereinafter, the manufacturing method and characteristics before and after recording of three types of image-receiving paper actually produced and an image-receiving paper produced as a comparative example will be explained.

(First Example) The base material was synthetic paper (manufactured by Tamago Oil Synthetic Paper, Yubo 150 μm).
m thickness), and on this substrate, 70 parts by weight of polyester acrylate, 20 parts by weight of diethylene glycol diacrylate, 6 inches of benzoin isobutyl ether.
The coating film thickness after curing of the image-receiving layer forming material having the composition "benzyl 4" is 20 μ-
Apply with a doctor blade so that After this, use a high pressure mercury lamp (80W/(:l).

The image-receiving layer forming material is irradiated with an irradiation distance of 101) to be cured to obtain an image-receiving layer (the image-receiving layer having this composition is referred to as image-receiving layer a).

(Second Example) The same synthetic paper as in the first example was used as the substrate, and on this substrate urethane acrylate 80 heavy weight neopentyl glycol diacrylate 10'' benzoin isobutyl ether 7'' benzyl
An image-receiving layer forming material having a composition of 3'' is applied in the same manner as in the first embodiment and irradiated with the high-pressure mercury lamp to obtain an image-receiving layer (the image-receiving layer having this composition is referred to as image-receiving layer 1iib).

(Third Example) Using art paper with a 50 o/m basis as a substrate, an image-receiving layer was coated on this substrate under the same conditions as in the second example, and irradiated with a mercury lamp to obtain an image-receiving layer.

Further, in order to compare the characteristics with the image receiving papers of the first to third embodiments prepared as described above, the following image receiving papers were prepared by a conventionally known method.

(Comparative example) A synthetic paper similar to the above was used as a base, and on this base were applied a linear saturated polyester resin (Vylon 200 manufactured by Toyobo), a linear saturated polyester resin (Vylon 300 manufactured by Toyobo), a linear saturated polyester resin (Vylon 300 manufactured by Toyobo), and a 15Φ weight part silicone oil. (Shin-Etsu Chemical IJx-62-2087) 1.7
A receiving paper forming material having the composition of ``calcium carbonate (Brilliant-1500 manufactured by Shiraishi Calcium) 0.3'' methyl ethyl ketone 34'' toluene 34'' was applied with a doctor blade so that the coating thickness after drying was 20 μm. °C
The mixture was dried for 10 minutes to obtain an image-receiving layer (the image-receiving layer having this composition is referred to as image-receiving layer C).

Furthermore, in order to actually record on the receiver papers of the first to third examples and comparative examples prepared as described above and evaluate their characteristics, a 6μ thick polyester film coated with a heat-resistant slipping layer was used. Sublimable dye (PTB-16 manufactured by Mitsubishi Kasei Co., Ltd.) on the opposite side of the heat-resistant slipping layer coated surface. Linear saturated polynisal resin (Vylon-290 manufactured by Toyobo Co., Ltd. manufactured by Toyobo Co., Ltd.) in the 5-fold section. Polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd.) in the type 1 assembly section. BX-1) 4 “Methyl ethyl ketone 50” Toluene
A transfer sheet was obtained by applying a thermal sublimation ink having a composition of 40" using a gravure printing machine.

In addition, as a thermal transfer recording device, the heating resistor density is 8.
A conventional thermal sublimation type one having a dot/as thermal head was used.

FIG. 3 is a table showing the glossiness and recording density before and after recording for the image-receiving papers of Examples 1 to 3 and Comparative Example described above. Macbeth reflex 11t!L; measured using tRD-918). As shown in the figure, when an ultraviolet curable resin is used for the image-receiving layer, the surface glossiness before recording is high, and even after recording, the glossiness of the recorded image does not decrease and is extremely 1! A recorded image with an image quality close to that of a salt photograph was obtained. When the surface of the image-receiving layer was observed under an electron microscope, it was confirmed that the surface before printing was slightly uneven, but the surface after printing was extremely smooth. This indicates that the surface after recording was smoothed by heat and pressure during recording by the thermal head. Such an effect could not be obtained when the image-receiving layer was formed from a thermoplastic or thermosetting resin such as a linear saturated polyester resin.

The present invention is not limited to the above description, but can also be applied to, for example, image receiving paper having an intermediate layer between the image receiving layer and the substrate.

Effects of the Invention As described above, according to the present invention, there is no need to make any changes to the thermal transfer recording device (the conventional thermal transfer recording device can be used as is, and it is possible to use a Victorian high-gloss recording device with high gloss). This method has the advantage of greatly contributing to the rapid spread of the dye sublimation type heat-sensitive transfer method.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of an embodiment of the present invention, Figure 3 is a characteristic comparison diagram showing the comparison results of the characteristics of the present invention and a conventional product, and Figure 4 is a cross-sectional view of a conventional product. . 1.6... Image receiving paper base (substrate), 2.7... Color material image receiving layer (image receiving layer), 3... Recording layer, 4... Ink layer,
5... Transfer paper base. Patent applicant: Victor Japan Co., Ltd. Figure 1 Figure 2 Figure 4 +A)

Claims (1)

[Claims] In an image receiving paper for thermal transfer recording having at least a colorant image receiving layer to which a colorant is transferred from a thermal transfer sheet and an image receiving paper base holding the colorant image receiving layer, the colorant image receiving layer is made of an ultraviolet curable resin. An image receiving paper for thermal transfer recording, characterized in that: