JPH06199052A - Image receiving substance for sumblimation heat transfer recording and sumblimation heat transfer recording method using it - Google Patents

Abstract

PURPOSE:To improve light-resistance and a shelf life by a method wherein transmissivity of light of an image receiving layer is set to a specified value and a difference in a free energy change when specified. CONSTITUTION:In an image receiving substance for sublimation heat transfer recording wherein a dyestuff image receiving layer formed of dyeing property resin is formed on a base material, when transmissivity (%) of light (wavelength lambdanm) per 1mum of the dye image receiving layer is T (lambda), a value of X defined by a formula described at the right is set to 2500 or less. Further, when a free energy change when a dye is mixed in dyeing property resin is set to -x1kj/mol, and when a free energy change when a dye is mixed in polyester, is set to -x2kj/mol, a difference DELTAG in a free energy change defined by DELTAG=(-x1) -(-x2) is set to Okj/mol or less. Polyvinyl vinylidene is used as dyeing property resin. This constitution provides excellent light resistance and shelf life and increases optical density of an image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sublimation heat transfer recording image receptor comprising a substrate and a dye receiving layer comprising a dyeable resin capable of being dyed with a dye such as a sublimable disperse dye. And a sublimation thermal transfer recording method using the same. More specifically, it relates to a sublimation thermal transfer recording image receptor having high light resistance, excellent storage stability, and capable of forming an image with high optical density, and a sublimation thermal transfer recording method using the same.

[0002]

2. Description of the Related Art In recent years, a thermal transfer recording method has been widely used as a method for recording an image, which has the advantages that a recording apparatus can be downsized and maintenance is simple. Among them, a sublimation thermal transfer recording method using a so-called sublimation dye or a heat diffusible dye which can provide an analog gradation expression by providing immediacy and further realize a high-quality image comparable to a silver salt color photograph, Widely used for hardcopying images such as video cameras, televisions and computer graphics.

The formation of an image by such a conventional sublimation thermal transfer recording method is performed by a transfer member having an ink layer made of a binder and a sublimable disperse dye formed on a substrate such as polyester, and a substrate such as synthetic paper. An image receptor such as photographic paper on which a dye-receptive layer made of a dyeable resin that can be dyed with a sublimable dye is formed, and the ink layer and the dye-receptive layer are placed in contact with each other, and a thermal head or laser The sublimation disperse dye is thermally transferred from the ink layer of the transfer body to the dye receiving layer of the image receiving body by selectively heating the ink layer of the transfer body according to image information by light or the like. In this case, the upper limit of the optical density of the obtained image is generally about 2.0.

[0004]

However, the image on the image receptor obtained by the conventional sublimation thermal transfer recording method is
There is a problem that it is easily deteriorated by light and has very poor light resistance. Further, there has been a strong demand to further improve the optical density of the image.

The present invention is intended to solve the above problems of the prior art, and to form an image having high light resistance, excellent storage stability, and high optical density on a sublimation thermal transfer image receptor. The purpose is to

[0006]

In connection with the object of the present invention, the inventors have found that the photodegradation of the formed image strongly depends on the light absorption in the ultraviolet region of the dye-receiving layer of the image receptor. That is, most of the photo-deterioration of the sublimable disperse dye thermally transferred to the image receptor is due to the components such as dyeing resin other than the sublimable disperse dye in the dye receiving layer being the ultraviolet rays of sunlight or fluorescent lamp. Area (2
(50 nm to 350 nm) and becomes a high energy state, which is caused by decomposing the sublimable disperse dye, and therefore the dye receiving layer of the image receptor is 250 nm to 350 nm.
The light resistance of the image can be improved by preventing the absorption of 350 nm ultraviolet rays over a certain amount.
The optical density of the formed image strongly depends on the compatibility between the dye to be transferred and the dyeing resin, and therefore the compatibility between the dye to be transferred and the dyeing resin in the dye receiving layer is increased. Found that it is possible to improve the optical density of the image,
This invention was completed.

That is, according to the present invention, in a sublimation thermal transfer recording image receptor having a dye receiving layer made of a dyeable resin formed on a substrate, light (wavelength λ per 1 μm of the dye receiving layer is used.
(1) when the transmittance (%) of (nm) is T (λ)

[0008]

[Equation 3] The value of X defined by is not more than 2500, and the change in free energy when the dye is mixed with the dyeing resin is −
When χ ₁ kJ / mol and the change in free energy when the dye is mixed with polyester are −χ ₂ kJ / mol, the formula (2)

[0009]

[Equation 4] The difference ΔG in free energy change defined by is 0 kJ / m
An image receptor for sublimation thermal transfer recording is provided which is less than or equal to ol.

The present invention also provides a dye-receiving layer for a sublimation heat transfer recording image-receiving body comprising a dye-receiving resin-made dye-receiving layer formed on a substrate from a transfer body having an ink layer containing the dye. In the sublimation heat transfer recording method for forming an image by transferring the dye to the above, there is provided a sublimation heat transfer recording method characterized by using the above-mentioned image receptor for sublimation heat transfer recording.

The present invention will be described in detail below.

The image receptor of the present invention is characterized in that the value of X defined by the formula (1) is 2500 or less. The meaning of X in formula (1) will be described with reference to FIG.

Most of the photo-deterioration of the sublimable disperse dye thermally transferred to the image receptor is caused by components such as dyeing resin other than the sublimable disperse dye in the dye receiving layer in the ultraviolet region of sunlight or fluorescent lamp. It absorbs light to a high energy state, which is caused by the decomposition of the sublimable disperse dye. Therefore, in order to prevent photodegradation, it is effective to form the dye receiving layer from a material that does not absorb ultraviolet rays. However, as shown in FIG. 1, the light absorption of the dye receiving layer itself of the image receiving material for sublimation thermal transfer recording is large in the wavelength region of less than 260 nm (far ultraviolet region) and from 260 nm to 350 nm (near ultraviolet region). It is a little in the wavelength range of. Also,
At 350 nm or more (up to 800 nm, visible region), when light in this wavelength range is absorbed, it appears colored and cannot be used as an image receptor, and therefore there is almost no light absorption.

As described above, the dye receiving layer of the conventional image receptor has absorption in the far-ultraviolet region and the near-ultraviolet region, but sunlight or a fluorescent lamp has substantially no light having a wavelength of less than 250 nm. The light to be considered in order to prevent the photo-deterioration of the sublimable disperse dye thermally transferred to the image receptor is 260 nm to 35 nm.
It becomes light in the wavelength range of 0 nm. That is, in order to prevent photodegradation of the sublimable disperse dye thermally transferred to the image receptor, it is more preferable to reduce the light absorption in the shaded area in FIG.

In this case, generally, the sunlight or the light of the fluorescent lamp is 2
Since a large amount of light in the wavelength range close to 350 nm is included in comparison with light in the wavelength range near 60 nm, it is considered that suppressing absorption of light in the wavelength range close to 350 nm is effective for preventing optical deterioration of an image. . Therefore, in the present invention, the formula (1) in which a factor of (λ-250) is introduced is considered as an index of the light absorption property of the dye receiving layer, and the weighted evaluation is performed at the light wavelength of 350 nm side rather than 260 nm. To That is, the factor of (λ-250) and λ nm
The value obtained by multiplying the absorption rate of light of wavelength (100-T (λ)) by the wavelength range of 260 nm to 350 nm is defined as X, and the light absorption property of the dye receiving layer is evaluated by the value of X. To do. The larger the value of X, the more easily photo-degradation of the sublimable disperse dye thermally transferred to the image receptor occurs, and conversely, the smaller the value of X, the less likely it occurs. However, in the present invention, X is set in consideration of practical requirements. 2,500 or less, preferably 500
Below.

Therefore, in the present invention, it is important to select a resin that satisfies such a value of X as the dyeing resin that constitutes the majority of the dye receiving layer. As such a resin, for example, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride or the like can be preferably used. In addition, the dye receiving layer may contain a plasticizer, a curing agent, a fluorescent stagnation agent, and silicone oil as minute components, and the value of X is 10
It is preferable to select those of 000 or less, preferably 5,000 or less.

When the numerical value of X is specifically determined, light having a wavelength of 260 nm to 350 nm is divided into 10 nm and the average transmittance (T (λ)) in the wavelength range is calculated. It is preferable.

In order to thermally transfer the dye of the transfer body to the dye receiving layer of the image receptor at a high transfer density, the higher the compatibility of the dyeing resin and the dye of the dye receiving layer is, that is, the higher the compatibility is. The larger the size, the better the dyeability and the higher the transfer density. Therefore, it is preferable to select, as the dyeing resin that constitutes the dye-receiving layer of the image receptor, one having a high compatibility with the dye.

Generally, regarding the compatibility when the dye is mixed with the resin, it can be said that the compatibility is better as the change in free energy during the mixing is larger in the negative direction. Further, in view of the fact that polyester is used as a dyeing resin for a conventional general image receptor, it is desired to have better compatibility with dyes than at least polyester.

Therefore, in the present invention, the compatibility between the dyeing resin and the dye is determined by the change in free energy when the dye is mixed with the dyeing resin-χ ₁ and the conventional general dyeing property. Change in free energy when mixed with a dye in polyester which is a resin-χ ₂ is used as an index, and this value is 0 kJ.
/ Mol or less. Specifically, a dyeable resin film or a polyester film (UE3600,
Unitika Co., Ltd.) containing a dye in an amount of 1 to 30% by weight, preferably 5 to 15% by weight, and bringing them into intimate contact with each other at an absolute temperature T. Preferably, the mixture is left at a high temperature of 20 ° C. for several hours to achieve an equilibrium distribution of the dye, and when the dye concentration in the dyeing resin at this time is C and the dye concentration in the polyester is C _PE , the free energy change of both Difference ΔG is expressed by the following equation (3)

[0021]

[Equation 5] (In the formula, R is a gas constant).

As the dyeing resin used in the dye receiving layer of the image receptor, a value of ΔG of 0 kJ / mol or less, preferably -2 kJ / mol or less is required to realize a practically sufficient transfer density. You can The dyeing resin showing such a value of ΔG varies depending on the type of dye used,
When a sublimable disperse dye is used as the dye, polyvinyl chloride, polyvinylidene chloride and the like can be preferably used.

In the present invention, the structure of the invention other than the above can be the same as the conventional one. For example, as the base material of the image receptor, conventionally used synthetic paper, coated paper, etc. can be preferably used.

As a method of forming an image using the image receiving material for sublimation thermal transfer recording of the present invention, the dye receiving layer of the image receiving element and the ink layer of the transfer element are superposed so as to face each other and, for example, depending on the image information, This can be carried out by irradiating a laser beam from the transfer body side to heat the ink layer to thermally transfer the dye. A sublimation thermal transfer recording method using such an image receptor for sublimation thermal transfer recording of the present invention is also included in the scope of the present invention.

The image-receiving member for sublimation heat transfer recording of the present invention can be manufactured by a conventional method. For example, it can be produced by applying a dye-receptive resin to a substrate with a wire bar or the like and drying.

[0026]

The image receptor for sublimation thermal transfer recording of the present invention is used as a dyeing resin constituting the dye receiving layer, and has a thickness of 260 nm to 350 nm.
Since a material having a small absorption of light in the wavelength range of m is used, it is possible to prevent the photodeterioration of the image without decomposing the dye thermally transferred to the dye receiving layer. Further, as the dyeing resin of the dye receiving layer, one having good compatibility with the dye is used, so that the transfer sensitivity can be improved.

[0027]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 Polyvinylidene chloride having an X value of 300 (Saran # 100)
0 W, manufactured by Denki Kagaku Kogyo Co., Ltd.) was applied to a synthetic paper made of polypropylene on a synthetic paper made of polypropylene so as to have a dry thickness of 1 μm, and dried to form a dye receiving layer. A photographic paper was manufactured.

For this printing paper, foron blue (manufactured by Sand Co.) having a ΔG value of -1.6 kJ / mol showing compatibility with polyvinylidene chloride was used as a transfer dye, and a video printer (CVP- G5, manufactured by Sony Corporation) was used for gradation printing.

The optical density of the highest density portion of the obtained image was measured by using a Macbeth densitometer.
8 showed a very high transfer density. Further, when the image was irradiated with xenon lamp light having an output of 400 mW / cm ² at 40 ° C., the residual ratio of the image was 95%, which was very excellent in light resistance.

Comparative Example 1 A photographic printing paper was produced in the same manner as in Example 1 except that polyester having a value of X of 13700 (UE3600, manufactured by Unitika Ltd.) was used as the dyeing resin, and gradation printing was performed. .
The value of ΔG showing the compatibility between the transfer dye, foron blue, and the compatibility with polyester was 0 kJ / mol.

As a result, the optical density of the highest density portion of the obtained image was 2.1, but the residual rate of the image was 20%, which was poor in light resistance.

Comparative Example 2 A photographic printing paper was produced in the same manner as in Example 1 except that a polycarbonate (Z-200, manufactured by Unitika Ltd.) having an X value of 3000 was used as the dyeing resin, and gradation printing was performed. went.
The value of ΔG showing the compatibility between the transfer dye, foron blue, and polycarbonate was −1.2 kJ / mol.

As a result, the optical density of the highest density portion of the obtained image was 2.4, but the residual rate of the image was 56%, which was poor in light resistance.

Comparative Example 3 As a dyeing resin, polyvinyl acetate (Al having an X value of 0) was used.
photographic paper was manufactured and gradation printing was performed in the same manner as in Example 1 except that (Drich Co., Ltd.) was used. It should be noted that Δ indicating the compatibility between the transfer dye, foron blue, and polyvinyl acetate.
The value of G was 1.2 kJ / mol.

As a result, the residual rate of the obtained image is 93%.
However, the optical density of the highest density part was 1.2, and the transfer density was very low.

[0037]

According to the present invention, an image having high light resistance, excellent storage stability and high optical density can be formed on an image receiving material for sublimation heat transfer.

[Brief description of drawings]

FIG. 1 is a light absorption characteristic diagram of a dye receiving layer of a conventional image receptor.

Claims (4)

[Claims] 1. A sublimation thermal transfer recording image receptor comprising a dye-receptive layer formed of a dyeable resin on a substrate, wherein the transmittance (%) of light (wavelength λ nm) per 1 μm of the dye-receptive layer is If T (λ), then equation (1) The value of X defined by is not more than 2500, and the change in free energy when the dye is mixed with the dyeing resin is −
Assuming that χ ₁ kJ / mol and the change in free energy when the dye is mixed with polyester are -χ ₂ kJ / mol, the formula (2): The defined difference in free energy change ΔG is 0 kJ / mo
An image receptor for sublimation thermal transfer recording, which is 1 or less. 2. The image receptor for sublimation thermal transfer recording according to claim 1, wherein the value of X is 500 or less, and the difference ΔG in free energy change is −2 kJ / mol or less. 3. A sublimation thermal transfer recording image receptor according to claim 1, wherein the dyeable resin is polyvinylidene chloride. 4. A dye-receiving layer of a sublimation heat transfer recording image-receiving body comprising a dye-receiving resin-made dye-receiving layer formed on a substrate from a transfer body having an ink layer containing the dye. A sublimation heat transfer recording method, wherein the sublimation heat transfer recording image receptor according to claim 1 is used in the sublimation heat transfer recording method for forming an image by transferring.