JP2001096922A - Thermal transfer recording medium, image receiving sheet and image forming method using them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer recording medium, an image receiving sheet and an image forming method thereof for preventing the lowering of the resolution power generated by the bleeding of an ink caused by a crystalline wax of low melting point, enhance the durability in the case of rubbing a transfer image or the like, realize the good area gradation and simultaneously achieve all the above. SOLUTION: A thermal transfer recording layer composed of a coloring pigment, an epoxy resin and a colorless or light color fine particles as main components and having the 2-1.0 μm film thickness is formed on a substrate, and the softening point of the epoxy resin is 70-150 deg.C, and blend ratio of an optional combination of the components of the thermal transfer recording layer is in the range of 20-60 pts.wt. coloring pigment, 40-70 pts.wt. epoxy resin and 5-30 pts.wt. fine particles, and the total of the coloring resin, epoxy and the fine particles is 100 pts.wt. or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for thermally transferring a thermal transfer recording layer of a thermal transfer recording medium (thermal transfer ribbon) provided with a thermal transfer recording layer containing a color pigment onto an image receiving sheet by a thermal head printer. More particularly, the present invention relates to a thermal transfer recording medium and an image receiving sheet for forming at least two or more colors to form a gray-scale color image based on a multi-color area gradation, and an image forming method using the same.

[0002]

2. Description of the Related Art Hitherto, as a thermal transfer recording system for forming a gradation image using a thermal head printer, a sublimation transfer system and a fusion transfer system are known. The sublimation transfer method is
A thermal transfer recording medium having a sublimable (heat transferable) dye and a binder resin provided on a support is superimposed on a thermal transfer recording medium and an image receiving sheet, and the sublimation dye in the thermal transfer recording layer is received according to the calorific value of the thermal head. The image is transferred onto a sheet to form a gradation image.

However, when an image is formed using such a sublimable (heat-migrating) dye, the formed image is inferior in durability, and its use in fields requiring heat resistance and light resistance is limited. You. In addition, the thermal recording sensitivity is lower than that of the melt transfer method, so the printer is driven by a battery such as a dry battery, making it smaller and lighter, and is not suitable as a high-speed recording material using a high-resolution thermal head expected to be used in the future. have.

On the other hand, in the melt transfer method, a thermal head or the like is heated by using a transfer sheet provided with a heat-meltable ink transfer layer made of a coloring material such as pigment or dye and a binder such as wax on a support. In this method, an image is formed by applying energy corresponding to image information to a device and fusing an ink transfer layer on an image receiving sheet.

[0005] The image formed by the melt transfer method is
It has high density and excellent sharpness, and is suitable for recording binary images such as characters and line drawings. Further, a color image can be formed by forming an image on the image receiving sheet by using a thermal transfer sheet made of yellow, magenta, cyan, and black. Japanese Patent Publication No. 63-65029 discloses such a thermal transfer sheet for forming a color image. However, in the case of the thermal transfer sheet described in JP-B-63-65029, since a low-melting crystalline wax is used as a binder for the ink layer, the resolving power tends to decrease due to ink bleeding. In addition, the fixing strength of the transferred image is low, and if the image portion is rubbed strongly by hand, the image portion is removed.

Various proposals have been made for solving such a phenomenon. For example, JP-A-61-24459
No. 2 proposes a heat-sensitive transfer sheet having a heat-sensitive ink layer comprising 65% or more of an amorphous polymer, a release material and a colorant. However, Japanese Patent Laid-Open No. 61-
The thermal transfer sheet described in Japanese Patent Publication No. 244592 also contains a crystalline wax, and therefore, the fixing strength of the portion where the superimposed printing of each color is performed is insufficient.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has been made in consideration of the problem of the ink resulting from the use of a low-melting crystalline wax as a binder for an ink layer. Prevents deterioration of resolution due to bleeding, and improves the point that if wax is used, the transferred image is not durable enough to be rubbed by hand and the image is easily removed and transferred. To provide a thermal transfer recording medium (thermal transfer ribbon) and an image receiving sheet capable of realizing good area gradation at the same time, and an image forming method using the same. With the goal.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have made it possible to solve the above problems by using a fusion transfer method.

That is, the invention according to claim 1 provides a heat transfer recording layer comprising a color pigment, an epoxy resin, and colorless or pale-colored fine particles as main components and having a thickness of 0.2 to 1.0 μm. The thermal transfer recording medium provided above, wherein the epoxy resin has a softening point of 70 to 150 ° C. Here, the “fine particles” serve as a filler, and “colorless or light color” means that there is substantially no effect on the color or density of the image transferred by the thermal transfer recording layer.

Further, in the invention according to claim 2, the thermal transfer recording layer is characterized in that the coloring pigment is in a range of 20 to 60 parts by weight,
The epoxy resin is in the range of 40 to 70 parts by weight, and the fine particles are in the range of 5 to 30 parts by weight, and the total amount of the coloring pigment, the epoxy resin, and the fine particles is 100 parts by weight or less. 2. The thermal transfer recording medium according to claim 1, wherein the composition ratio is a combination of the following combinations.

In the second aspect, the total amount of the coloring pigment, the epoxy resin, and the fine particles in the thermal transfer recording layer is 100 parts by weight or less, but the meaning of "the following" is as follows. That is, the thermal transfer recording layer contains only the above-mentioned main components (colored pigment, epoxy resin, and fine particles) alone, and the case where other compositions other than the above-mentioned main components are appropriately contained for some reason. In the case of the former, the total amount of the coloring pigment of the thermal transfer recording layer, the epoxy resin, and the fine particles is 100 parts by weight, and if the latter, the coloring pigment of the thermal transfer recording layer, the epoxy resin, And the total of the fine particles is less than 100 parts by weight (in this case, the total of the color pigment, the epoxy resin, the fine particles, and the other composition is 100 parts by weight). That is, the combination ratio of the coloring pigment, the epoxy resin, and the fine particles in the thermal transfer recording layer is appropriately selected with respect to 100 parts by weight in each of the two cases.

If another composition is added to the thermal transfer recording layer (that is, the latter case), specific examples include a dispersant represented by a surfactant and the like. The ratio is 0.1 to 10 parts by weight based on 100 parts by weight in the latter case. If the weight ratio of the other composition is too small, the effect of the other composition will not be sufficiently exhibited.On the contrary, if the weight ratio of the other composition is too large, all of the initial problems of the present invention will be sufficient. It is difficult to solve to meet. When the other composition is a dispersant, its role is aimed at the following effects. That is, in order to provide a thermal transfer recording layer on a support, generally, an appropriate amount of a volatile solvent is added to a composition having an appropriate mixing ratio to form a thermal transfer recording layer to form a coating liquid. It is carried out by applying an appropriate amount to the appropriate place on the support and then volatilizing the solvent component.At this time, a problem that may be caused by undesired agglomeration of the coloring pigment or fine particles is caused. When it occurs, by adding a dispersant in the coating liquid, it is possible to impart a preferable dispersibility to the color pigments and fine particles,
An object of the present invention is to solve a problem which is considered to be caused by the aggregation.

The invention according to claim 3 is the thermal transfer recording medium according to claim 1 or 2, wherein the colorless or light-colored fine particles in the thermal transfer recording layer are silica.

According to a fourth aspect of the present invention, there is provided an image processing apparatus comprising:
4. The method according to claim 1, wherein three colors of magenta and yellow, or four colors of black, cyan, magenta and yellow are repeatedly arranged side by side in the longitudinal direction on the support. Or a thermal transfer recording medium.

According to a fifth aspect of the present invention, there is provided an image receiving sheet wherein the image receiving layer is provided on a support, and the image receiving surface of the image receiving layer is formed of an epoxy resin.

According to a sixth aspect of the present invention, the thermal transfer recording layer of the thermal transfer recording medium according to any one of the first to fourth aspects is thermally transferred onto an image receiving sheet using a thermal head printer to form an image by area gradation. In the image forming method, an image receiving sheet on which an epoxy resin layer is formed on an image receiving surface is used.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle of transfer of a thermal transfer recording medium according to the present invention is as follows. Heat is applied to a thermal transfer recording material by a thermal medium such as a thermal head. Is dissolved, tackiness is developed, and an image is recorded by being thermally bonded on the image receiving sheet. Therefore, when printing is performed with at least two or more colors superimposed, a clear print without blurring of the ink can be obtained. Further, the transferred recorded image has excellent mechanical strength.

Hereinafter, the thermal transfer recording medium of the present invention will be described in detail. FIG. 1 shows a thermal transfer recording medium (1) according to the present invention in which a thermal transfer recording layer (3) is provided on a support (2).

The support (2) that can be used in the present invention
As the material, those generally used for sublimation transfer type and melt transfer type can be used. Specifically, plastic films such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, polycarbonate, polyvinyl chloride, polystyrene, polyimide, nylon, polyvinylidene chloride,
Papers such as condenser paper and paraffin paper can be mentioned, and polyester films are particularly preferable. The thickness of the support (2) is 2 to 50 μm, more preferably 2 to 16 μm. The thermal transfer recording layer (3)
It consists of a color pigment, an epoxy resin, and colorless or light-colored fine particles.

The epoxy resin contained in the thermal transfer recording layer (3) has a softening point in the range of 70.degree. C. to 150.degree. C. in consideration of printability to a heat medium such as a thermal head and durability of an image after transfer recording. Use things. The thermal conditions for thermal transfer using a thermal head are usually 300 to 4
It is several milliseconds at 00 ° C, which is 5 seconds at 100 to 150 ° C when converted to static conditions. Further, in order to perform thermal transfer recording as described above, it is necessary to heat until the epoxy resin is dissolved.

Therefore, considering the amount of heat supplied from the thermal head and the state of dissolution of the epoxy resin, the upper limit of the melting point is 150 ° C. If a resin exceeding this upper limit is used, more energy is required during transfer,
This is because the life of the thermal head becomes extremely short. The lower limit is set at 70 ° C. in consideration of the retention stability of the image after transfer recording. If an epoxy resin having a melting point of less than 70 ° C. is used, tailing may occur if rubbed by hand. This is because the phenomenon described above occurs.

The epoxy resin used as a main material in the thermal transfer recording layer of the present invention is particularly preferably characterized in that the epoxy equivalent (the number of grams of resin containing one gram of epoxy group) is from 600 to 5000, and the molecular weight is Is 800
~ 5000.

If the epoxy equivalent of this epoxy resin is
If the value is lower than the lower limit (less than 600), the durability of the image to rubbing is insufficient, and if the image is rubbed by hand, tailing tends to occur in the transferred image, which is not preferable. Conversely, if the epoxy equivalent is higher than the upper limit (above 5,000), the thermal energy required for thermal transfer is too large, and the life of the thermal head is shortened. However, since the sensitivity of thermal transfer is low, it is not suitable for use in thermal transfer recording of images at high speed, which is not preferable.

Then, the molecular weight of the epoxy resin is
If the value is lower than the lower limit (less than 800), the durability of the image to rubbing is not sufficient, and if the image is rubbed by hand, tailing tends to occur in a transferred image, which is not preferable. Conversely, if the molecular weight is higher than the upper limit, (5,
(More than 000), the thermal energy required for thermal transfer is too large, shortening the life of the thermal head, or the sensitivity of thermal transfer is low. It is not preferable because it is unsuitable for the use.

The most preferred epoxy resin in the present invention is one in which all properties such as softening point, epoxy equivalent and molecular weight are simultaneously within the respective ranges described above. This case is preferable because high effects can be obtained particularly with respect to image transferability and durability.

For the above reasons, the melting point is 70-150 ° C.,
Epoxy equivalent of 600-5000 and molecular weight of 800
An epoxy resin in the range of ~ 5000 is selected. Examples of such an epoxy resin include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcinol diglycidyl ether,
Glycidyl ether type epoxy resins such as cresol novolac polyglycidyl ether, tetrabromobisphenol A diglycidyl ether, bisphenol hexafluoroacetone glycidyl ether, glycidyl ester type epoxy resins such as phthalic acid diglycidyl ester, dimer acid diglycidyl ester, and triglycidyl Glycidylamine type epoxy resins such as isocyanurate, tetraglycidylaminodiphenylmethane, and tetraglycidylmethaximendiamine, and aliphatic epoxy resins such as hexahydrobisphenol A diglycidyl ether, polypropylene glycol diglycidyl ether, and neopentyl glycol diglycidyl ether. Can be mentioned. Any of these may be selected.

The colorless or light-colored fine particles contained in the thermal transfer recording layer (3) are used to improve the transferability at the time of thermal transfer, more specifically, the dot shape on which the transferred image is formed, and the gradation reproducibility. The use of a colorless or light-colored component is a necessary component in order not to impair the color development of a colored image formed by thermal transfer. Examples of such colorless or light-colored fine particles include silica, calcium carbonate, kaolin, clay, starch, zinc oxide, Teflon (registered trademark) powder, polyethylene powder, polymethyl methacrylate resin beads, polyurethane resin beads, benzoguanamine and melamine. Resin beads and the like can be mentioned. Among the above, silica fine particles are particularly preferred.

As the color pigment contained in the thermal transfer recording layer (3), various known pigments can be used. As an example, carbon black is preferable for black single-color printing, and pigments forming yellow, magenta, and cyan, and four-color pigments obtained by adding black to these three-color pigments are used for multi-color printing. These pigments can be used alone or in combination of two or more.

The composition of the composition for forming the thermal transfer recording layer (3) is based on 100 parts by weight of the total solid content.
20 to 60 parts by weight of color pigment, 40 to 7 of epoxy resin
0 parts by weight, 1 to 30 parts by weight of colorless or light-colored fine particles. When the amount of the coloring pigment is less than the above range, a desired printing density cannot be obtained, and when the amount of the coloring pigment is too large, the film strength is unfavorably reduced. If the amount of the epoxy resin is less than the above range, the film strength is unfavorably reduced, and if the amount is too large, the transferability, more specifically, the dot shape on which the transferred image is formed, and the gradation reproducibility are unfavorably deteriorated. When the amount of colorless fine particles is less than the above range, transferability, in particular, the dot shape on which a transferred image is formed, and the gradation reproducibility are not preferable, and when the amount is large, good ink fluidity is obtained. Absent. In addition, various additives can be blended as needed. The amount of addition is 1 to 100 parts by weight of the composition for forming the thermal transfer recording layer.
The content is preferably 0 parts by weight or less.

The method for producing a thermal transfer recording medium according to the present invention is characterized in that a composition obtained by dispersing or dissolving a colorant, an epoxy resin and colorless fine particles in a solvent on a substrate such as coated paper or plastic is coated with a bar coater. It is formed by applying a solvent coat method such as a blade coat, an air knife coat, a gravure coat, a roll coat and the like, and drying to form a thermal transfer recording layer.

The thickness of the thermal transfer recording layer (3) is from 0.2 to
1.0 μm is desirable. When the film thickness is less than 0.2 μm, it is difficult to obtain a sufficient density, and when the film thickness is more than 1.0 μm, it becomes difficult to perform transfer according to the heat-generating portion of the thermal head. The gradation reproducibility is inferior.

The thermal transfer recording layer (3) of the support (2)
When the thermal transfer recording layer (3) is transferred onto the image receiving sheet by applying heat from the side not provided with the thermal transfer recording layer (3), the thermal head adheres to the support (2) and the thermal transfer recording medium (1) In order to prevent smooth running, it is desirable to provide a back coat layer (4) on the side of the support (2) where the thermal transfer recording layer (3) is not provided.

Examples of the material used for the back coat layer (4) include nitrocellulose, polyester resin, acrylic resin, vinyl resin and the like containing silicon oil, or silicon-modified resin. it can. Further, a crosslinking agent may be used in combination for the purpose of improving heat resistance. The coating thickness when providing the back coat layer (4) is preferably about 0.1 to 4 μm.

The image receiving sheet used to form an image using the above-described thermal transfer recording medium (1) includes:
Examples include papers such as high quality paper and coated paper, plastic films such as polyester film, polyvinyl chloride film and polypropylene film, and paper or plastic film coated with an image receiving layer.
The image receiving layer used here is preferably an epoxy resin. That is, by using an epoxy resin as the image receiving layer, even when the thermal transfer recording layer of the thermal transfer recording medium is not sufficiently melted at the time of thermal transfer, the thermal transfer recording layer and the image receiving layer are well adhered to each other by the heat at the time of thermal transfer. Since printing is performed by cutting the foil, transferability, more specifically, the dot shape on which the transfer image is formed, and gradation reproducibility are improved. Further, the formed image has excellent image resistance such as abrasion resistance and scratch resistance.

When it is difficult to form an image directly on a sheet on which an image is to be formed, an image may be formed once on the image receiving sheet, and then the transferred image may be re-transferred to a final sheet. . Such an indirect transfer method not only widens the selectivity of the final sheet, but also provides a protective layer on the final transfer image by providing a protective layer on the image receiving sheet, thereby improving the image resistance and improving image resistance. By providing a security layer such as a hologram forming layer on the sheet, it is possible to improve the security of the final transfer image.

The means for applying thermal energy used to obtain a gradation image expression by area gradation using the thermal transfer recording medium of the present invention as described above and the image receiving sheet as described above may be any of conventionally known applying means. Can be used, and a gradation image can be obtained by controlling the heat energy.

[0037]

Next, the present invention will be described more specifically with reference to examples. In the following description, “parts” or “%” is based on weight unless otherwise specified.

Example 1 First, an ink composition for a thermal transfer recording layer having the following composition was prepared. (Cyan ink) Phthalocyanine blue ... 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007) ... 20 parts * Softening point 128 ° C, epoxy equivalent 1750-2200, molecular weight 2900 colorless fine particles (silica: Nippon Aerosil Aerosil R972) ... 4 parts Methyl ethyl ketone… 67 parts

(Magenta ink) Carmine 6B: 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007): 20 parts * Softening point: 128 ° C., epoxy equivalent: 1750-2200, molecular weight: 2900 Colorless fine particles (silica: Aerosil manufactured by Nippon Aerosil Co., Ltd.) R972) 4 parts Methyl ethyl ketone 67 parts

(Yellow Ink) Disazo Yellow 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007) 20 parts * Softening point 128 ° C., epoxy equivalent 1750-2200, molecular weight 2900 colorless fine particles (silica: Aerosil manufactured by Nippon Aerosil Co., Ltd.) R972) 4 parts Methyl ethyl ketone 67 parts

The ink for a thermal transfer recording layer having the above formulation was applied to a 5.4 μm-thick polyethylene terephthalate film whose back surface was subjected to heat treatment so as to have a dry film thickness of 0.7 μm, and then dried. A thermal transfer recording medium was obtained.

Next, an image-receiving sheet was obtained by applying the following image-receiving layer ink to the easily-adhesive surface of the 100-μm easily-adhesive polyester film so as to have a dry film thickness of 5 μm and drying.

(Image receiving layer ink) Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007) ... 30 parts * Softening point 128 ° C, epoxy equivalent 1750-2200, molecular weight 2900 methyl ethyl ketone ... 70 parts

The thermal transfer recording layer surface of the thus obtained cyan thermal transfer recording medium was superimposed on the image receiving sheet, and a cyan image having an area gradation corresponding to the heat generating portion of the thermal head was obtained using a thermal head. Next, using a magenta thermal transfer recording medium, a magenta image based on area gradation was formed on an image receiving sheet on which a cyan image was formed in the same manner as for cyan. Similarly, a yellow image was formed, and a color image consisting only of area gradation was formed on the image receiving sheet.

Comparative Example 1 The following sublimation transfer type ink composition was prepared as an ink for a thermal transfer recording layer. (Cyan ink) C.I. I. Solvent Blue 63: 5 parts Butyral resin (BX-1 manufactured by Sekisui Chemical Co., Ltd.): 5 parts Methyl ethyl ketone: 60 parts Toluene: 30 parts

(Magenta Ink) I. Disperse Red 60: 5 parts Butyral resin (BX-1 manufactured by Sekisui Chemical Co., Ltd.): 5 parts Methyl ethyl ketone: 60 parts Toluene: 30 parts

(Yellow Ink) C.I. I. Disperse Yellow 201 5 parts Butyral resin (BX-1 manufactured by Sekisui Chemical Co., Ltd.) 5 parts Methyl ethyl ketone 60 parts Toluene 30 parts

The ink for a thermal transfer recording layer having the above formulation was applied to a 5.4 μm-thick polyethylene terephthalate film whose back surface was subjected to heat treatment so as to have a dry film thickness of 1.0 μm, followed by drying. Was obtained.

Next, the following ink for a dye-receiving layer was applied to the easy-adhesion surface of the 100-μm easy-adhesion polyester film so as to have a dry film thickness of 4 μm, and dried.
Aging was carried out at a temperature of 1 ° C. for one week to obtain an image receiving sheet.

(Ink for Dye Receiving Layer) Acetal resin ... 10 parts Vinyl chloride-vinyl acetate copolymer resin ... 10 parts Silicon oil ... 2 parts Isocyanate resin ... 3 parts Methyl ethyl ketone ... 50 parts Toluene ... 25 parts

The surface of the thermal transfer recording layer of the obtained thermal transfer recording medium was superimposed on the surface of the dye receiving layer of the image receiving sheet, and an image was formed in the order of yellow, magenta and cyan using a thermal head to obtain a color image.

Comparative Example 2 A thermal transfer recording medium was produced in the same manner as in Example 1, except that the dry film thickness of the ink for the thermal transfer recording layer was changed to 1.2 μm for each of cyan, magenta and yellow. A color image was formed.

Comparative Example 3 Example 1 was repeated except that the ink for the thermal transfer recording layer was changed to the following formulation.
A thermal transfer recording medium was prepared in the same manner as described above to form a color image.

(Cyan Ink) Phthalocyanine Blue 9 parts Epoxy resin (made by Yuka Shell Epoxy: Epicoat 1007) 20 parts * Softening point 128 ° C, epoxy equivalent 1750-2200, molecular weight 2900 methyl ethyl ketone 71 parts

(Magenta ink) Carmine 6B: 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007): 20 parts * Softening point: 128 ° C., epoxy equivalent: 1750-2200, molecular weight: 2900 methyl ethyl ketone: 71 parts

(Yellow Ink) Disazo Yellow: 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007): 20 parts * Softening point: 128 ° C. Epoxy equivalent: 1750-2200 Molecular weight: 2900 Methyl ethyl ketone: 71 parts Phthalocyanine blue: 10 parts

Comparative Example 4 Example 1 was repeated except that the ink for the thermal transfer recording layer was changed to the following formulation.
A thermal transfer recording medium was prepared in the same manner as described above to form a color image.

(Cyan Ink) Phthalocyanine Blue 9 parts Epoxy resin (made by Yuka Shell Epoxy: Epicoat 1001) 20 parts * Softening point 64 ° C Epoxy equivalent 450-500 Molecular weight 900 Colorless fine particles (silica: Aerosil R972 manufactured by Nippon Aerosil) ... 4 parts Methyl ethyl ketone ... 67 parts

(Magenta ink) Carmine 6B 9 parts Epoxy resin (made by Yuka Shell Epoxy: Epicoat 1001) 20 parts * Softening point 64 ° C Epoxy equivalent 450-500 Molecular weight 900 Colorless fine particles (silica: Aerosil R972 manufactured by Nippon Aerosil) ... 4 parts Methyl ethyl ketone ... 67 parts

(Yellow Ink) Disazo Yellow: 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1001): 20 parts * Softening point: 64 ° C. Epoxy equivalent: 450 to 500 Molecular weight: 900 Colorless fine particles (silica: Aerosil R972 manufactured by Nippon Aerosil) ... 4 parts Methyl ethyl ketone ... 67 parts

Comparative Example 5 Example 1 was repeated except that the ink for the thermal transfer recording layer was changed to the following formulation.
A thermal transfer recording medium was prepared in the same manner as described above to form a color image.

(Cyan ink) Phthalocyanine blue: 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1010): 20 parts * Softening point: 169 ° C. Epoxy equivalent: 3000 to 5000 Molecular weight: 5500 Colorless fine particles (silica: Aerosil R972 manufactured by Nippon Aerosil) ... 4 parts Methyl ethyl ketone ... 67 parts

(Magenta ink) Carmine 6B 9 parts Epoxy resin (made by Yuka Shell Epoxy: Epicoat 1010) 20 parts * Softening point 169 ° C Epoxy equivalent 3000-5000 Molecular weight 5500 Colorless fine particles (silica: Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.) ... 4 parts Methyl ethyl ketone ... 67 parts

(Yellow Ink) Disazo Yellow 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1010) 20 parts * Softening point 169 ° C. Epoxy equivalent 3000-5000 Molecular weight 5500 Colorless fine particles (silica: Aerosil R972 manufactured by Nippon Aerosil) ... 4 parts Methyl ethyl ketone ... 67 parts

The images obtained in Example 1 and Comparative Examples 1, 2, 3, 4, and 5 were evaluated for image gradation, light fastness, and security.

[0066]

[Table 1]

Image gradation: ○: The produced color image is faithfully reproduced from the highlight to the shadow ×: The reproducibility from the highlight to the shadow is insufficient. Light fastness: illuminated the color image surface with a xenon fade meter for 80 hours, and measured the fading rate. ：: Fading rate of 5% or less ×: Fading rate of 5% or more Fixing property: Degree of tailing of the image portion when the color image surface is rubbed with a normal force with a nail. ○: No change ×: Dirt around image area

As shown in the table, in the thermosensitive recording medium according to the present invention (Example 1), a color image produced in gradation reproducibility is faithfully reproduced from a highlight portion to a shadow portion.
An excellent thermal transfer recording medium having the durability of an image after recording can be obtained, and the object of the present invention has been achieved.

<Example 2> In Example 1, the following black ink was added to the three colors of cyan, magenta and yellow as the ink composition for the thermal transfer recording layer to form a color image by mixing four colors. did.

(Black ink) Carbon black: 9 parts Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007): 20 parts * Epoxy equivalent: 1750-2200 Softening point: 128 ° C. Molecular weight: 2900 Colorless fine particles (silica: Aerosil R972 manufactured by Nippon Aerosil) ... 4 parts Methyl ethyl ketone ... 67 parts

The obtained image was confirmed to have the same performance as in Example 1.

<Embodiment 3> In Embodiment 1, a color image was created by mixing three colors of cyan, magenta, and yellow, and a binary image of characters and bar codes was created in black. It was confirmed that the obtained image had excellent resistance to characters and barcode portions in addition to the performance of Example 1.

Example 4 Using the thermal transfer recording medium obtained in Example 1, an image was formed on the following image receiving sheet.

(Construction of Image Receiving Sheet) Each of the following inks was applied to a 25 μm polyester film in sequence and dried to obtain an image receiving sheet in which a release layer and an image receiving layer were sequentially laminated.

(Ink for release layer) Acrylic resin 20 parts Methyl ethyl ketone 40 parts Toluene 40 parts

(Ink for image receiving layer) Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007) ... 30 parts * Epoxy equivalent 1750-2200 Softening point 128 ° C Molecular weight 2900 Methyl ethyl ketone ... 70 parts

The image-receiving sheet on which the image was formed was superimposed on the sheet for the final product, and thermal transfer was performed from the back of the image-receiving sheet with a heat roller, and only the polyester film was peeled off. I got it.

Example 5 Using the thermal transfer recording medium obtained in Example 1, an image was formed on the following image receiving sheet.

(Construction of Image Receiving Sheet) The following ink for a release layer and an ink for a hologram forming layer are sequentially applied to a 25 μm polyester film and dried to obtain a release layer and a hologram forming layer. A hologram was formed on the surface of the substrate by using an uneven shape.

(Ink for release layer) Acrylic resin 20 parts Methyl ethyl ketone 40 parts Toluene 40 parts

(Ink for Hologram Forming Layer) Vinyl chloride-vinyl acetate copolymer: 20 parts Urethane resin: 15 parts Methyl ethyl ketone: 70 parts Toluene: 30 parts

Further, ZnS was provided on the surface of the hologram forming layer by vapor deposition as a transparent thin film layer, and then the following ink for an image receiving layer was applied and dried to laminate the image receiving layers to obtain an image receiving sheet.

(Ink for Image-Receiving Layer) Epoxy resin (manufactured by Yuka Shell Epoxy: Epicoat 1007) ... 20 parts * Epoxy equivalent 1750-2200, softening point 128 ° C, molecular weight 2900 Urethane resin ... 10 parts Methyl ethyl ketone ... 70 parts

The image-receiving sheet on which the image was formed was overlapped with a final product sheet having an ultraviolet-emitting fluorescent agent printed on the surface, and thermal transfer was performed with a heat roller from the back of the image-receiving sheet.
When only the polyester film was peeled off, a good transfer member having a protective layer on the surface could be obtained.

The obtained transfer body had a hologram image as a security function, and had high security. The results of Examples 2 to 5 are also shown in Table 1.

[0086]

According to the present invention, the thermal transfer recording layer contains a color pigment, a binder resin (epoxy resin), and colorless or light-colored fine particles (filler), and the thermal transfer recording layer is placed on the image receiving sheet by a thermal head printer. It is possible to form an image with excellent gradation reproducibility by area gradation, and the image after transfer is excellent in storability, especially light resistance and mechanical strength. A thermal transfer recording medium (thermal transfer ribbon), an image receiving sheet, and an image forming method using them can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view using a cross section of an embodiment of a thermal transfer recording medium according to the present invention. Y indicates yellow, M indicates magenta, and C indicates cyan.

FIG. 2 is an explanatory view using a cross section of another embodiment of the thermal transfer recording medium according to the present invention. Y indicates yellow, M indicates magenta, and C indicates cyan.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thermal transfer recording medium 2 ... Support 3 ... Thermal transfer recording layer 4 ... Back coat layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B41M 5/26 101L F-term (Reference) 2C068 AA06 BB08 BB11 BB22 BC03 BC13 BC33 BD23 2H111 AA08 AA26 AA33 AA47 AA48 BA03 BA33 BA38 BA47 BA48 BA49 BA50 BA53 BA55 BA71 CA03 CA12 CA30 4F071 AA20 AA24 AA42A AA43 AA73 AH12 BB02 BC01

Claims (6)

[Claims] A color pigment, an epoxy resin, and colorless or light-colored fine particles as main components, and a film thickness of 0.2 to 1.
A thermal transfer recording layer having a thickness of 0 μm is provided on the support, and the epoxy resin has a softening point of 70 to 150 ° C .;
A thermal transfer recording medium characterized by the following. 2. The thermal transfer recording layer, wherein the color pigment is in a range of 20 to 60 parts by weight, the epoxy resin is in a range of 40 to 70 parts by weight, and the fine particles are in a range of 5 to 50 parts by weight.
The compounding ratio of any combination in a range of from about 30 parts by weight to about 30 parts by weight, and a total amount of the coloring pigment, the epoxy resin, and the fine particles is 100 parts by weight or less. Thermal transfer recording medium. 3. The thermal transfer recording medium according to claim 1, wherein the colorless or light-colored fine particles in the thermal transfer recording layer are silica. 4. The thermal transfer recording layer according to claim 1, wherein the thermal transfer recording layer comprises three colors of cyan, magenta, and yellow, or black, cyan,
4. The thermal transfer recording medium according to claim 1, wherein four colors of magenta and yellow are repeatedly arranged side by side on the support in a longitudinal direction. 5. An image receiving sheet, wherein an image receiving layer is provided on a support, and an image receiving surface of the image receiving layer is formed of an epoxy resin. 6. A thermal transfer recording medium according to claim 1, wherein the thermal transfer recording layer of the thermal transfer recording medium is thermally transferred onto an image receiving sheet on the basis of image data. An image forming method for forming an image by area gradation, wherein an image receiving sheet having an epoxy resin layer formed on an image receiving surface is used.