JPH0971057A - Laminating method of image protective layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently laminate regardless of density of an image when the image is to be formed by using an ink ribbon in a printer and further when lamination is to be performed by transferring an image protective layer on the image by using a transfer type image protective film. SOLUTION: In a laminating method of an image protective layer wherein a thermal transfer image is printed on a transfer medium and an image protective layer of a transfer type image protective film is to be laminated thereon by thermal transfer, laminate energy of the image protective layer is changed according to printing energy at the time of image formation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laminating an image protective layer on an image formed on a transfer medium such as photographic paper for surface protection of the image. More specifically, the present invention relates to a method of laminating an image protective layer on an image by thermally transferring the image protective layer of a transferable image protective film.

[0002]

2. Description of the Related Art Conventionally, for the purpose of protecting an image formed on an object to be transferred such as photographic paper, particularly an image formed by a sublimation type thermal transfer system using a sublimable or heat diffusible dye. It is made to laminate a transparent film on. Here, as a mode of image protection required for the transparent film, the image is shielded from a gas that causes image deterioration, the discoloration or fading of the image is prevented by providing the transparent film with an ultraviolet absorbing ability, and the image is protected. There are a wide variety of applications, such as imparting plasticizer resistance to prevent the dye forming the film from migrating to an article containing various plasticizers such as eraser, imparting abrasion resistance, imparting sebum resistance, and the like.

Various methods for laminating transparent films are also known. For example, a transparent film is thermocompression-bonded to an image surface using a heat roller, or a transparent film is adhered using an adhesive at room temperature. It has been known. In addition, a transfer type image protective film is prepared by laminating an image protective layer made of a thermoplastic resin on a base film, and the image protective layer of the transfer type image protective film is thermally transferred onto the protected image to form an image on the image. A method for forming an image protective layer (that is, a transparent film) is also known (JP-A-60-2).
04397, JP-A-59-85793, and JP-A-59-76298). According to such a transfer type image protection film, only the portion of the image protection layer that is heated at the time of thermal transfer can be laminated on the protected image, so that it is possible to prevent curling of the photographic printing paper after lamination. Become. It is also possible to form an image protective layer in the ink ribbon used for forming an image and laminate the image protective layer inside the printer following image formation.

[0004]

By the way, when an image is formed on photographic paper with a printer using an ink ribbon,
In order to secure the running property of the ink ribbon, it is necessary that the ink ribbon has releasability from the surface of the printing paper. Therefore, a releasing agent is used on the surface of the photographic paper or the surface of the ink ribbon to enhance the releasability between them.

However, if a releasing agent is used on the surface of the photographic paper to improve its releasability, the photographic paper of the image protective layer is laminated when the image protective layer is laminated by thermal transfer using a transferable image protective film after image formation. However, there is a problem that the adhesion of the image protective layer is reduced and it becomes difficult to laminate the image protective layer.

When an image is formed on a photographic printing paper whose surface is releasable by a release agent and an image protective layer is thermally transferred onto the image, the higher the image density, the higher the adhesiveness. On the contrary, the lower the image density, the lower the adhesiveness of the image protective layer, so that there is a problem that it is difficult to uniformly laminate. This is because the release agent on the surface of the printing paper is transferred to the surface of the ink ribbon by printing.
This may reduce the releasability of the photographic paper surface and increase the adhesiveness of the image protective layer, or the dye may be transferred from the ink ribbon to the photographic paper, reducing the releasability of the photographic paper surface, and It is considered that this is because the adhesiveness of the protective layer is enhanced.

On the contrary, when a releasing agent is used on the surface of the ink ribbon to enhance its releasability, an image is formed on the photographic paper by using such an ink ribbon, and the image protection is performed on the image. When the layer is thermally transferred, the release agent is also transferred at the same time when the dye is transferred from the ink ribbon to the printing paper, so the higher the image density, the higher the releasing property of the printing paper and the lower the adhesiveness of the image protection layer. To do. Therefore, also in this case, there is a problem that it is difficult to uniformly laminate.

To solve the problem that it is difficult to carry out uniform lamination due to the different adhesiveness between the printing paper and the image protective layer depending on the image density, the energy for laminating the image protective layer is It is also possible to raise it.
However, if the laminating energy of the image protection layer is excessively increased, the base film of the transfer image protection film is damaged or the primer layer and the image protection layer which are usually provided between the base film and the image protection layer are If the adhesion of the image protective layer is excessively increased, peeling failure of the image protective layer from the base film is likely to occur.

The present invention is intended to solve the problems of the prior art as described above, in which an image is formed using an ink ribbon in a printer, and a transfer type image protective film is used to form an image protective layer on the image. When transferring and adhering, the image protection layer is laminated on the photographic paper with a uniform adhesive force while ensuring the running property of the ink ribbon and enhancing the adhesion of the image protection layer, and regardless of the image density. The purpose is to be able to.

[0010]

Means for Solving the Problems When the present invention uses a transfer-type image protective film to laminate an image protective layer on an image by thermal transfer, the lamination energy of the image protective layer is determined as the printing energy during image formation. It was found that the above object can be achieved by controlling according to the above, and the present invention has been completed.

That is, the present invention provides a method for laminating an image protective layer, which comprises printing a thermal transfer image on a transfer target and laminating the image protective layer of a transfer type image protective film thereon by thermal transfer. Provided is a laminating method characterized in that energy is changed according to printing energy at the time of image formation.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to the drawings. In each drawing, the same reference numerals represent the same or equivalent constituent elements.

FIG. 10 shows a sublimation-type thermal transfer ink ribbon and a transfer-type image protection film which can be used in the practice of the present invention, in which the sublimation-type thermal transfer ink ribbon and the transfer-type image protection film are integrated. FIG. 2 is a plan view (FIG. (A)) and a cross-sectional view (FIG. (B)) of a general laminate-integrated ribbon.

The present invention can be carried out by using a known ink ribbon or a transfer type image protective film when forming a thermal transfer image and laminating an image protective layer thereon. Therefore, the ribbon 1 of FIG.
Similar to a known ribbon, a primer layer 3 is formed on a substrate film 2, and an ink layer 4 of each color of yellow Y, magenta M, and cyan C and a sensor mark 5 are formed on the surface of the primer layer 3 in sequence. The image protection layer 6 may be formed on the same surface as the above, and the heat resistant slipping layer 7 may be further provided on the back surface of the base film 2.

Here, each component of the ribbon 1 can be configured in the same manner as a known ribbon. For example, the base film 2 can be formed of a polyester film, a polyimide film or the like having a thickness of 3 to 20 μm. .

The primer layer 3 is provided to enhance the adhesion between the base film 2 and the ink layer 4, and the constituent material of the primer layer 3 is the base film 2 and the ink layer 4.
Although it can be appropriately selected depending on the type of resin constituting the above, it can be generally formed from urethane resin, acrylic resin, polyester resin, or the like.

The ink layer 4 is made of, for example, a cellulosic resin such as methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose butyrate acetate, cellulose acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetoacetal, polyvinyl acetate, polystyrene or the like. It is possible to disperse a sublimable or heat diffusible dye in the above vinyl resin or various urethane resins. The thickness of the ink layer 4 is not particularly limited, and is usually about 0.5 to 5 μm.
m.

The image protection layer 6 of FIG. 10 is made of a single layer of thermoplastic resin, and has a function of adhering to a protected image such as photographic paper at the time of thermal transfer, and an image of ultraviolet rays, a plasticizer,
It also has the function of protecting from sebum and the like. The thermoplastic resin forming such an image protective layer 6 is a resin that adheres well to the image forming surface of photographic paper by thermal transfer and that protects the image from ultraviolet rays, plasticizers, sebum, etc. A resin that also has the function of can be appropriately used. For example, cellulose acetate butyrate resin, vinyl chloride-vinyl acetate copolymer and the like can be used. As the image protection layer 6 of the ribbon 1 in FIG. 10, a mode in which the single image protection layer 6 having both the function as the adhesive layer and the function as the image protection layer as described above is provided is shown. However, the present invention can also be applied to a ribbon having an adhesive layer and a protective layer as separate layers as an image protective layer.

The heat resistant slipping layer 7 prevents the base film 2 from being fused to the thermal head of the printer when the thermal transfer image is formed and the image protective layer 6 is laminated on the image by the thermal transfer printer. However, it is provided in order to ensure smooth traveling of the ribbon 1. Such a heat resistant slipping layer 7 can be formed from a resin having a high softening point such as cellulose acetate or polyvinyl butyral resin. Further, a lubricant such as silicone oil, wax, fatty acid amide, or phosphoric acid ester may be applied on such a resin layer or added in the resin layer, or a filler may be added in the resin layer. .

When an image is formed by a printer using the ribbon of FIG. 10 and an image protective layer is laminated on the image, first, a thermal head of the printer is used to form an ink layer 4 of each color of yellow Y, magenta M and cyan C. Are sequentially heated to form an image on the photographic paper, and then the image protection layer 6 is heated,
The image protection layer in the heated portion is transferred onto the image.

In this case, if the surface of the printing paper is treated with a release agent, the relationship between the printing energy and the printing density during image formation is generally high as shown in FIG. 1 (a). The higher the image density, the higher the image density. The relationship between the print density in this case and the minimum lamination energy required for laminating the image protective layer on the image is as shown by the broken line X in FIG. The lower the minimum laminating energy is, the better. Here, when the lamination energy of the image protection layer is set to a constant value slightly higher than the minimum lamination energy at the lowest print density (dotted line A in FIG. 1B), the thermal head of the printer Therefore, the heat storage amount becomes large, the image protection layer 6 becomes difficult to peel from the primer layer 3 during lamination of the image protection layer 6, and a problem of peeling failure occurs. Further, it is not preferable to spend more energy than necessary for the laminating of the image protective layer from the viewpoint of saving energy consumption. On the contrary, when the lamination energy of the image protection layer 6 is set to a constant value that is slightly higher than the minimum lamination energy at the maximum print density (dotted line B in FIG. 1B).
In such a case, the image protective layer 6 is less likely to adhere to the photographic paper when the image protective layer 6 is laminated, which causes a problem of adhesion failure.

Therefore, in the present invention, the image protection layer 6
The lamination energy of the image protection layer is changed so as to have a negative correlation with the printing density (that is, the printing energy) without setting the lamination energy of No. to a fixed value. For example, as shown by the solid line in FIG. 1B, the lamination energy of the image protection layer is monotonically decreased as the print density increases. This makes it possible to laminate the image protective layer on the image with a uniform adhesive force regardless of the print density.

Further, in the present invention, when the minimum lamination energy becomes lower as the printing density becomes higher as shown by the broken line in FIG. 1 (b), the lamination energy of the image protective layer is increased as the printing density is increased. It is not always necessary to decrease monotonically. For example, as shown in FIG. 1C, the lamination energy monotonically decreases as the print density increases in the region of the lowest print density to the medium region, but in the region of the medium print density or higher, The laminating energy of the image protection layer may be a constant value. Further, as shown in FIG. 1D, the laminating energy may be lowered stepwise as the printing density becomes higher. As shown in FIG. 1E, the lamination energy of the image protection layer may be set to be always higher than the minimum lamination energy by a constant value. As shown in FIG. 1F, the lamination energy of the image protection layer is set to a constant value in the region of the lowest print density to the medium, but the print density becomes high in the region of the middle or higher print density. Therefore, the laminating energy may be monotonically decreased. In addition, these FIG. 1 (c)-(f)
Also in, the broken line X represents the minimum lamination energy of the image protection layer 6.

In FIG. 1, the method of the present invention was described for the case where the surface of the printing paper was treated with a release agent. When the surface of the ink layer 4 was treated with a release agent, the print density and The relationship with the minimum lamination energy is shown in FIG.
As indicated by the broken line X in (e), the minimum lamination energy increases as the print density increases. Therefore,
In such a case, in the present invention, the laminating energy of the image is changed so as to have a positive correlation with the print density. For example, as shown by the solid line in FIG. 2A, the lamination energy of the image protection layer is monotonically increased with the increase of the print density. In addition, as shown in FIG. 2B, the lamination energy of the image protection layer is constant in the region where the print density is the lowest to the medium, but the print density is increased in the region where the print density is medium or higher. As a result, the laminating energy is monotonically increased. As shown in FIG. 2C, the lamination energy may be increased stepwise as the print density increases. FIG. 2 (d)
As described above, the lamination energy of the image protection layer may be set to be always higher than the minimum lamination energy by a constant value. As shown in FIG. 2E, the laminate energy monotonically increases with the increase of the print density in the region where the print density is the lowest to the medium range, but is set to a constant value in the region where the print density is medium or higher. Good.

When the surfaces of both the printing paper and the ink layer are treated with a release agent, the relationship between the printing density and the minimum lamination energy is as shown by the broken line in FIG. 3 or 4. There is also. Therefore, in such a case, as shown by the solid lines in FIGS. 3 and 4, respectively, the lamination energy of the image protection layer is adjusted according to the relationship between the printing density and the minimum lamination energy depending on whether the printing density is high or low. It is preferable to change it.

As described above, changing the laminating energy of the image protective layer according to the printing density (that is, the printing energy) makes it easy to perform the image formation and the image protective layer lamination in the same printer. It can be carried out. For example, when the printing energies of yellow Y, magenta M, and cyan C are Yn, Mn, and Cn, the laminating energy Ln of the image protection layer is expressed by the following formula (1).

[0027]

Ln = aYn + bMn + cCn (1) (where a, b, and c are arbitrary coefficients), and can be set based on the sum of the printing energies of each color in each pixel. Alternatively, the laminating energy of the image protection layer may be set based on the largest printing energy of each color in each pixel. Further, when the ink layer is composed of a single color, the lamination energy of the image protection layer may be changed based on the printing energy of the single ink layer.

When the image formation and the laminating of the image protective layer are carried out by the same printer, the alignment between the printed image and the image protective layer laminated on the image is
Since image formation and lamination can be performed by a series of operations, it can be performed extremely easily.

The present invention can be applied to the case where an image is formed using ribbons of various modes other than the laminate-integrated ribbon shown in FIG. 10 and an image protective layer is laminated on the image. For example, the ribbon shown in FIG. 10 shows an example in which the ink layers of yellow Y, magenta M, and cyan C are formed as the ink layers 4 in a frame sequential manner.
Further, an ink layer of black or the like may be formed, or an ink layer of any single color may be formed. In addition, the present invention can be applied to a ribbon provided with a layer containing an ultraviolet agent or a fluorescent whitening agent, etc., if necessary, and can also be applied to a ribbon having no primer layer.

As described above, according to the laminating method of the image protective layer of the present invention, the laminating energy of the image protective layer is changed according to the printing energy at the time of image formation. Therefore, even if the adhesiveness between the image protection layer and the printing paper changes according to the printing density on the printing paper, the image protection layer can be laminated on the printing paper with an appropriate adhesive force in response to the change. It will be possible. Therefore, it becomes possible to uniformly laminate the image protection layer on the printing paper. In addition, it is possible to prevent unnecessary energy from being consumed for laminating the image protection layer, so that it is possible to reduce energy consumed for laminating the image protection layer.

[0031]

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

Example 1 A primer layer-forming coating composition having the composition (a) shown in Table 1 below was applied to the surface of a PET film whose back surface was heat-treated with a gravure coater to a dry thickness of 0.1 μm. On top of this, the composition (b _Y ) of Table 2, the composition (b _M ) of Table 3 and the composition (b _C ) of Table 4 for the ink layer forming of each color of yellow, magenta, and cyan were dried to a thickness of 1 μm. The composition is applied in a frame-sequential manner with a gravure coater, and then the coating composition for forming an image protective layer having the composition (c) in Table 5 is applied with a gravure coater to a dry thickness of 3 μm, and a sublimation type thermal transfer ink ribbon and a transfer type image protective film are applied. A ribbon in which and are integrated was produced.

[0033]

[Table 1] [Coating for forming primer layer: composition (a)] (wt%) Polyurethane (NP-3151, manufactured by Nippon Polyurethane Co., Ltd.) 2 Polyisocyanate (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) 1 Methyl ethyl ketone 47 Toluene 50

[0034]

[Table 2] [Yellow ink layer forming coating composition (b _Y )] (wt%) Yellow dye (ESC Yellow 155, manufactured by Sumitomo Chemical Co., Ltd.) 4 Butyral resin (Denka Butyral 3000K, Denki Kagaku Kogyo) )) 6 Methyl ethyl ketone 45 Toluene 45

[0035]

[Table 3] [Paint for forming magenta ink layer: composition (b _M )] (wt%) Magenta dye (ESC Bordeaux 451, manufactured by Sumitomo Chemical Co., Ltd.) 2.5 Magenta dye (Bayfax 2670, manufactured by Bayer Japan) 2.5 Butyral Resin (Denka Butyral 3000K, manufactured by Denki Kagaku Kogyo Co., Ltd.) 5 Methyl ethyl ketone 45 Toluene 45

[0036]

[Table 4] [Cyan ink layer forming coating composition (b _C )] (wt%) Cyan dye (Foron Blue SR-PI, manufactured by Sand Co.) 4 Butyral resin (Denka Butyral 3000K, manufactured by Denki Kagaku Kogyo Co., Ltd.) ) 6 Methyl ethyl ketone 45 Toluene 45

[0037]

[Table 5]
[Paint for forming image protective layer: Composition (c)] (wt%) Cellulose acetate butyrate (CAB551-0.01, manufactured by Eastman Chemical Co.) 16 Cellulose acetate butyrate (CAB500-5, manufactured by Eastman Chemical Co.) 4 Methyl ethyl ketone 40 Toluene 40 On the other hand, a synthetic paper (Yupo FPG-150, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) was coated with a dye-receiving layer-forming coating composition having the following composition (d) to a dry thickness of 5 μm. Was formed.

[0038]

[Table 6][Dye-Receptive Layer Forming Coating: Composition (d)] (wt%) Cellulose acetate butyrate (CAB551-0.01, Eastman Chemical Co., Ltd.) 10 Cellulose acetate butyrate (CAB500-5, Eastman Chemical Co., Ltd.) 10 Silicone oil (SF8427, Toray Dow Corning Silicone Co., Ltd.) 2.5 DCHP (dicyclohexyl phthalate) 5 Polyisocyanate (Coronate L, Nippon Polyurethane Co., Ltd.) 2.5 Methyl ethyl ketone 35 Toluene 35

Then, using the above ribbon on the obtained printing paper, a thermal head having an average resistance of 3 kΩ and 8 lines / mm,
Applied voltage 20.0V, printing pulse width 17ms / lin
e, print with the head pressure of 300 g / cm as follows,
The image protection layer was laminated.

First, three of yellow, magenta and cyan
A black steer step image was printed by superimposing colors, and the image density was measured by a visual filter of a Macbeth densitometer TR924. As a result, the relationship between printing energy and image density as shown in FIG. 5 was obtained.

Next, the minimum lamination energy for laminating the image protective layer on this black image was determined with respect to the printing energy of this black image. As a result, the relationship shown by Bk in FIG. 6 was obtained as the relationship between the printing energy and the minimum lamination energy. From FIG. 6, in the system of Example 1 in which the photographic printing paper contained the release agent (silicone oil) and the ink layer did not contain the release agent, the minimum lamination was performed as the printing energy increased. You can see that the energy is low.

Therefore, as the lamination energy of the image protective layer with respect to the printing energy, (a) in FIG.
Three types shown in (b) and (c) were set. Where (a)
And (b), the lamination energy of the image protection layer,
It shows that it is constant regardless of the printing energy.
Then, for each of the three types of laminating energies of the image protective layer, the formation of the steer step image and the laminating of the image protective layer were continuously performed. Also in this case,
Laminate the image formation and image protection layer at room temperature (25
C.), high temperature (35.degree. C.) and low temperature (5.degree. C.).

As a result, under normal temperature environment (25 ° C.),
The image protective layer could be satisfactorily laminated on the black image with any of the laminating energies of (a), (b) and (c). In a high temperature environment (35 ° C),
The image-protecting layer could be satisfactorily laminated with the laminating energies of (b) and (c), but with the laminating energy of (a), the heat storage amount in the thermal head of the printer became excessively large, and the image protection was partially protected. Poor peeling of the layers from the ribbon occurred. In a low temperature environment (5 ° C),
With the laminating energies of (a) and (c), the image protective layer could be satisfactorily laminated, but with the laminating energy of (b), poor adhesion of the image protective layer occurred in the low density region of the image.

Next, using the above ribbon,
C.), high temperature (35.degree. C.) and low temperature (5.degree. C.), a natural image was printed in three environments, and subsequently an image protective layer was laminated. In this case, the laminating energy of the image protection layer is selected from among the printing energies (Yn, Mn, Cn) of the respective colors of yellow, magenta, and cyan for each pixel, and the lamination energy of the image protection layer is selected as follows. Lamination energy Ln was set.

[0045]

## EQU2 ## Ln = kMax (Yn, Mn, Cn) (In the formula, k is a coefficient.)

Here, by appropriately setting k, the value shown in FIG.
As shown in (d), (e), and (f) above, three kinds of laminating energies were set. Here, (d) and (e) represent that the lamination energy of the image protection layer is constant regardless of the printing energy. In FIG. 7, “Bk” represents the relationship between the printing energy of the black image and the minimum lamination energy,
“Monochromatic” represents the relationship between the printing energy of any one of yellow, magenta, and cyan and the corresponding minimum lamination energy.

As a result, when the image protection layer is laminated with the lamination energy (f), the temperature is high (35 ° C.).
Under any environment of low temperature (5 ° C.), the image protection layer was well laminated in all areas from the high density image area to the low density image area of the natural image. On the other hand, when the image protection layer is laminated with the laminating energy (d), the high temperature environment (35
When printing and laminating was carried out at (° C.), the amount of heat stored in the thermal head of the printer became excessively large in the area where the image density was high, and the peeling of the image protective layer from the ribbon was defective. Further, in the case of laminating with the laminating energy (e), when printing and laminating were performed in a low temperature environment (5 ° C.), adhesion failure occurred in the light-colored image portion.

From the above results, when the surface of the printing paper contains a release agent like the printing paper used in this example, an image is formed on the printing paper and the image protective layer is formed on the image. When the image is laminated, whether the image is a black image or a color natural image, the lamination energy of the image protection layer is increased according to the relationship between the printing energy and the minimum lamination energy. It can be seen that it is preferable to lower it.

Example 2 In the production of the ribbon used in Example 1, a silicone oil (SF8427, manufactured by Toray Dow Corning Silicone Co., Ltd.) was used in addition to the above-mentioned components as a coating material for forming the ink layer when forming the ink layer of each color. ) To solid content of 0.5 wt%
(0.05 wt% in the paint) was used. Further, in order to form the image protective layer, the first image protective layer-forming coating composition having the composition (e1) shown in Table 7 and the second image protective layer-forming coating composition having the composition (e2) shown in Table 8 below are formed by PET. The surface of the film is sequentially coated to form two layers, and as the image protection layer, a laminate of a first image protection layer (dry thickness 3 μm) and a second image protection layer (dry thickness 3 μm) is formed. A ribbon was made.

[0050]

[Table 7] [First paint for forming image protective layer: composition (e1)] (wt%) Cellulose acetate butyrate (CAB551-0.2, manufactured by Eastman Chemical Co.) 20 Methyl ethyl ketone 40 Toluene 40

[0051]

[Table 8] [Second coating material for forming image protective layer: composition (e2)] (wt%) Vinyl chloride-vinyl acetate copolymer 20 (Denka vinyl # 1000D, manufactured by Denki Kagaku Kogyo Co., Ltd.) Methyl ethyl ketone 40 Toluene 40

As printing paper, synthetic paper (Yupo FP
G-150, manufactured by Oji Yuka Synthetic Paper Co., Ltd., was first coated with a primer layer-forming coating composition having the composition (f) shown in Table 9 below to a dry thickness of 1 μm.
Then, a coating composition for forming a dye-receptive layer having the composition (g) shown in Table 10 below was applied so as to have a dry thickness of 8 μm.

[0053]

[Table 9][Coating for forming primer layer: composition (f)] (wt%) Chlorinated polyolefin (Super Clone 822, manufactured by Nippon Paper Industries Co., Ltd.) 42.5 Trifunctional epoxy resin (Epototo YH300, manufactured by Toto Kasei Co., Ltd.) 1.5 Tertiary amine catalyst (DBU) 0.1 Toluene 55.9

[0054]

[Table 10] [Coating for forming dye receiving layer: composition (g)] (wt%) Vinyl chloride-vinyl acetate copolymer 24 (Denka vinyl # 1000D, manufactured by Denki Kagaku Kogyo Co., Ltd.) Plasticizer (dibenzyl phthalate) : D-160, manufactured by Mitsubishi Kasei Vinyl Co., Ltd. 6 Methyl ethyl ketone 35 Toluene 35

A black image was printed on the obtained photographic paper in the same manner as in Example 1 using the above ribbon, and the image density was measured. As a result, the relationship between the printing energy and the printing density as shown in FIG. 8 was obtained.

Further, the minimum lamination energy required for laminating the image protection layer of the above ribbon on this black image was determined for the printing energy of this black image. As a result, the relationship shown by Bk in FIG. 9 was obtained as the relationship between the printing energy and the minimum lamination energy. From FIG. 9, in the system of Example 2 in which the ink layer contains a releasing agent (silicone oil) and the surface of the printing paper does not contain a releasing agent, the minimum lamination is accompanied by an increase in the printing energy. You can see that the energy is increasing.

Therefore, as the lamination energy of the image protective layer with respect to the printing energy, (g) in FIG.
Three types shown in (h) and (i) were set. Where (g)
And (h), the lamination energy of the image protection layer is
It shows that it is constant regardless of the printing energy.
Then, for each of the three types of laminating energies of the image protective layer, the formation of the steer step image and the laminating of the image protective layer were continuously performed. Also in this case, the image formation and the lamination of the image protective layer are performed at room temperature (25 ° C.),
The test was performed in three environments of high temperature (35 ° C) and low temperature (5 ° C).

As a result, when the image protective layer was laminated with the laminating energy (g), the high temperature environment (3
When printing and laminating was performed at 5 ° C.), the amount of heat stored in the thermal head of the printer became excessively large, resulting in defective peeling of the image protective layer from the ribbon. Further, when the image protective layer is laminated with the laminating energy (h) or (i), high temperature (35 ° C.) to low temperature (5 ° C.)
The image protective layer could be laminated well under any of the above environments. However, in the case of laminating with the laminating energy (h), it means that the laminating energy is consumed unnecessarily as compared with the case of laminating with the laminating energy (i). It turns out that it is preferable to laminate in (i).

[0059]

According to the present invention, when an image is formed using an ink ribbon in a printer and the image protective layer of a transfer type image protective film is laminated on the image by thermal transfer, the image density depends on the printed image. In addition, the image protection layer can be satisfactorily laminated on the image. In this case, it is possible to reduce unnecessary energy consumption used for laminating the image protection layer.

[Brief description of drawings]

FIG. 1 is a relationship diagram between printing energy and printing density (FIG. 1A) or a relationship diagram between printing density and laminating energy (FIGS. 2B to 2F).

FIG. 2 is a relationship diagram between print density and laminating energy ((a) to (e) in the same figure).

FIG. 3 is a relationship diagram between print density and lamination energy.

FIG. 4 is a relationship diagram between print density and lamination energy.

FIG. 5 is a relationship diagram between printing energy and printing density in the example.

FIG. 6 is a relationship diagram between printing energy and laminating energy in an example.

FIG. 7 is a relationship diagram between printing energy and laminating energy in the example.

FIG. 8 is a relationship diagram between printing energy and printing density in the example.

FIG. 9 is a relationship diagram between print density and lamination energy in the example.

10A and 10B are a plan view (the same figure (a)) and a sectional view (the same figure (b)) of a laminate-integrated ribbon in which a sublimation-type thermal transfer ink ribbon and a transfer-type image protection film are integrated.

[Explanation of symbols]

 1 Laminate-integrated ribbon 2 Base film 3 Primer layer 4 Ink layer 5 Sensor mark 6 Image protection layer 7 Heat resistant slipping layer

Claims (4)

[Claims] 1. A method of laminating an image protective layer, comprising printing a thermal transfer image on a transfer medium and laminating the image protective layer of a transfer type image protective film on the image by thermal transfer. A laminating method characterized by changing the printing energy according to time. 2. The laminating method according to claim 1, wherein the printing energy during image formation has a positive correlation with the laminating energy of the image protective layer. 3. The laminating method according to claim 1, wherein the printing energy at the time of image formation has a negative correlation with the laminating energy of the image protective layer. 4. The laminating method according to claim 1, wherein when a thermal transfer image is formed by superposing images of a plurality of colors, the laminating energy of the image protective layer is changed according to the sum of the printing energies of the images of the respective colors.