JP2000094845A - Heat-transfer recording medium, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an insufficient density and an insufficient light-fastness in the cass of a sublimation transfer method, and an insufficient gradation property in the case of a fusion transfer method, and provide a transmitting image which is excellent in a light-transmitting base material by forming a heat-transfer recording layer into a specified film thickness using a binder resin of a specified softening point. SOLUTION: For this heat-transfer recording medium 1, a heat-transfer recording layer 3 is provided on a supporting body 2. The heat-transfer recording layer 3 contains at least a coloring pigment and a binder resin. The binder resin is various kinds of resins such as a polyamide resin, a petroleum resin, an ethylene-vinyl acetate copolymer, and a polyethylene resin, and the softening point is 40-150 deg.C. When the softening point becomes lower than 40 deg.C, a blocking becomes easy to occur at the time of a storage of the recording medium, and when exceeding 150 deg.C, the transfer sensitivity decreases. Then, the film thickness is 0.2-1.0 μm. When the film thickness becomes lower than 0.2 μm, a sufficient density cannot be provided, and when exceeding 1.0 μm, a transfer in response to a thermal head heating portion becomes difficult, and the tone reproductivity becomes unfavorable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head printer in which a thermal transfer recording layer containing a color pigment is thermally transferred onto a light-transmissive image-receiving sheet to form a gradation image based on area gradation. 1. Field of the Invention The present invention relates to a thermal transfer recording medium and an image forming method used for applications such as a seal and a seal. As an application of the present invention, the image receiving layer can be retransferred to a transparent substrate (three-dimensional or the like). Further, the present invention relates to a thermal transfer recording medium and an image forming method that can be used for security applications such as securities, cash vouchers, and identification cards by adding a pattern such as a luminescent fluorescent agent.

[0002]

2. Description of the Related Art Conventionally, a sublimation transfer method has been known as a thermal transfer recording method for forming a gradation image using a thermal head printer. The sublimation transfer method with excellent gradation is based on a thermal transfer recording medium, which has a thermal transfer recording layer composed of a sublimable (heat transferable) dye and a binder resin, provided on a support, and superimposed on an image receiving sheet. In response, the sublimation dye in the thermal transfer recording layer is transferred onto an image receiving sheet to form a gradation image, and is now rapidly spreading and expanding as a substitute for photography. However, when printing on a light-transmitting image-receiving sheet using this sublimable (heat-migrating) dye, the image density is extremely low as compared with an image printed on a normal image-receiving sheet, which is not practical. This is due to the fact that the plastic sheet generally used for the transmissive image receiving sheet does not have sufficient heat insulating properties, the color density of the dye is reduced, and the difference between the transmission density and the reflection density. Normally, the image formed on the image receiving sheet is measured by reflection density. In this case, the light enters the formed image, is reflected by the base material, passes through the image and enters the eye, and the reflection density is actually measured. become. Further, there is a problem that an image formed by a sublimation dye is easily discolored by ultraviolet rays, so that it has been conventionally difficult to use or store it outside. For this reason, when an image is formed using a sublimation dye on a light-transmitting image-receiving sheet, the same image is printed twice to increase the density, or a dye having high sensitivity is used at a high density. A method has been developed, but the former requires twice the printing time as usual, and in the latter case, the burden on the printer side increases, such as increasing the heating energy to the print head higher than normal, Since the ratio becomes high, the storage stability of the ink ribbon is adversely affected, and improvement is desired. In order to prevent fading of an image, a method of adding an ultraviolet absorber to a protective layer (OL layer) provided on the image can be considered, but it is disadvantageous in terms of speed and cost, and the absorber is consumed. It has also been pointed out that fading progresses rapidly after this.
In the case of a transparent substrate, light transmission is on the opposite side of the OL layer,
That is, it is also from the substrate side, and in this case, the effect of the absorbent cannot be expected. Further, addition of a fluorescent light-emitting agent for improving the design and security of the image cannot be used because it has an adverse effect on light resistance. In the case of the melt transfer method, pigments are used to provide excellent fading, and the transmission density can be increased by increasing the thickness of the transfer layer to increase the pigment concentration.
In the case of a ribbon containing a wax or the like as a main component, the strength of the ink film is weak and the thickness of the ink film is large, so that the shape of the dot cannot be controlled. For this reason,
It is very difficult to form a so-called photographic image.

[0003]

As described above, when an image is formed on a light-transmitting substrate, the density and light resistance are insufficient when a sublimable (heat transferable) dye conventionally used is used. Another object of the present invention is to obtain an excellent transmission image in which the lack of gradation is improved when using a fusion transfer method.

[0004]

In order to achieve the above object, according to the present invention, first, in claim 1, a thermal transfer recording layer containing a color pigment and a binder resin is provided on a support, The softening point is 40 to 150 ° C., the thickness of the thermal transfer recording layer is in the range of 0.2 to 1.0 μm, and the image receiving sheet or the final transfer object has light transmittance. This is a thermal transfer recording medium.

According to a second aspect of the present invention, a thermal transfer recording layer containing a color pigment and a binder resin is provided on a support in advance, and the binder resin has a softening point of 40 to 150 ° C.
And the thickness of the thermal transfer recording layer is 0.2 to 1.0 μm
Prepare a thermal transfer recording medium that is in the range, using a thermal head printer, thermal transfer the thermal transfer recording layer of the thermal transfer recording medium on a light-transmissive image receiving sheet, in an image forming method of forming an image by area gradation, An image forming method is characterized in that at least one of the colors has a density of 0.8 or more.

According to a third aspect of the present invention, there is provided the image forming method according to the second aspect, wherein the thermal transfer recording layer contains a luminescent fluorescent agent.

[0007]

The thermal transfer recording layer has a softening point as defined in claim 2.
When the film thickness is in the range of 40 to 150 ° C. and the film thickness is in the range of 0.2 to 1.0 μm, it is easy to form an image by area gradation, and it is difficult to obtain a transmission image by the sublimation transfer type. Can be obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
FIG. 1 shows that a thermal transfer recording layer (3) is provided on a support (2).
1 shows a thermal transfer recording medium (1) according to the present invention. In the present invention
The support (2) that can be used includes a
What is commonly used for flower transfer type and melt transfer type
Can be used. Specifically,
Phthalate, polyethylene naphthalate, polypropylene
, Cellophane, polycarbonate, polyvinyl chloride,
Polystyrene, polyimide, nylon, polyvinyl chloride
Plastic film such as den, condenser paper
Papers such as paper and paraffin paper.
Preferred is a polyester film. Support
(2) has a thickness of 2 to 50 μm, more preferably 2 to 16 μm.
μm. The thermal transfer recording layer (3) has at least a colored face
Material and binder resin. Contained in thermal transfer recording layer (3)
Various known pigments can be used as the coloring pigment to be used.
You. One example is the use of carbohydrate for black monochrome printing.
Black is preferable, and for multicolor printing, yellow
-, Magenta and cyan pigments and their three color faces
Use four color pigments with black added to the pigment. These faces
Charges are used alone or in combination of two or more
It is also possible. Bars contained in the thermal transfer recording layer (3)
For example, polyamide resin, petroleum resin
Fat, ethylene-vinyl acetate copolymer, polyethylene tree
Fat, polypropylene resin, polystyrene resin, polyes
Terresin, vinyl chloride-vinyl acetate copolymer, polyvinyl
Alcohol, polycarbonate resin, polyvinyl butyral
Lal resin, polyvinyl acetal resin, methyl acrylic
Rate, ethyl acrylate, butyl acrylate, etc.
Acrylic esters, acrylic acid, methyl methacrylate
Acrylate, ethyl methacrylate, butyl methacrylate
Such as methacrylic esters and methacrylic acid, maleic
Acid and maleic acid esters, maleic anhydride,
Lilonitrile and the like can be mentioned. These binders
-The softening point of the resin is preferably 40 to 150 ° C.
No. When the softening point falls below 40 ° C, the thermal transfer recording medium is stored.
When blocking occurs, the occurrence of blocking is likely to occur.
If the temperature exceeds 50 ° C., the transfer sensitivity may decrease.
I will. The weight ratio of the binder resin to the color pigment is
30-400% is desirable. Coloring pigment for binder resin
If the weight ratio of the thermal transfer recording layer is less than 30%,
(3) The film strength is weakened, and background stains and the like during printing may occur.
It will be easier. If the concentration exceeds 400%, a sufficient concentration is obtained.
The problem is that it becomes difficult to Thermal transfer recording layer
Light is emitted by ultraviolet rays among the luminescent fluorescent agents that can be added to (3).
Ultraviolet light emitting fluorescent agent is excited by ultraviolet light,
Emitted when returning to lower energy levels
Are in the wavelength range of blue, green, red, etc.
High purity phosphor of zinc sulfide and sulfide of alkaline earth metal
In addition, trace amounts of metals (copper, silver,
Gun, bismuth, lead, etc.) as activators,
It can be obtained by firing at high temperature,
Depending on the combination of activators, hue, brightness, and color decay
The degree can be adjusted. Such an ultraviolet light emitting fluorescent agent
For ZnS: Cu, Ca_TwoB_FiveO₉Cl: Eu²⁺, C
aWO_Four, ZnO: Zn, Zn_TwoSiO_Four: Mn, Y_Two
O_TwoS: Eu, ZnS: Ag, YVO_Four: Eu, Y_TwoO
_Three: Eu, Gd_TwoO_TwoS: Tb, La_TwoO_TwoS: Tb,
Y_ThreeAl _FiveO₁₂,: Ce, etc., which may be used alone or
Is used by mixing several kinds. (Where the fluorescent agent is usually
Indicated by composition, host crystal as the main component and
Divide into activators or luminescent centers dispersed and connect with (:).
For example, ZnS: Cu has a host crystal of ZnS and an activator of ZnS: Cu.
In addition, the infrared-emitting fluorescent agent is excited by infrared light and emits visible light.
Infrared-visible conversion fluorescent agent that emits light and infrared light (800 nm)
Excitation and emission at longer wavelength (980-1020nm)
There is something to do. As the former infrared-visible conversion fluorescent agent,
YF_Three: Yb + Er, YF_Three: Yb + Tm, BaFC
1: Yb + Er and the like. Also, the latter
At 800 nm, and a longer wavelength (980 nm).
As a fluorescent agent that emits light at 1020 nm), LiNd
_0.9Yb_0.1P_FourO₁₂, LiBi_{0. Two}Nd_0.7Yb_0.1
P_FourO₁₂, Nd_0.9Yb_0.1Nd_Five(MoO_Four)_Four, N
aNd_0.9Yb_0.1P_FourO₁₂, Nd_0.8Yb_0.2Na_Five
(WO_Four)_Four, Nd_0.8Yb _0.2Na_Five(Mo_0.5W
_0.5O_Four)_Four, Ce_0.05Gd_0.05Nd_0.75Yb_0.15Na
_Five(W_0.7Mo_0.3O_Four)_Four, Nd_0.9Yb_0.1Al_Three
(BO_Three)_Four, Nd_0.9Yb_0.1Al_2.7Cr_0.3(B
O_Three)_Four, Nd_0.6Yb_0.4P_FiveO₁₄, Nd_0.8Yb
_0.2K_Three(PO_Four)_TwoAnd the like. Add luminescent fluorescent agent
The addition amount is based on the total amount of the coloring pigment and the binder resin.
Therefore, the content is desirably 0.1 to 100% by weight. 0.1
If the content is less than 10% by weight, the luminous intensity is weak and the design
Poor security and more than 100% by weight
Is not preferable because the density of the transferred image is insufficient. Change
The heat transfer recording layer (3) contains heat from the support (2).
For adjusting the peeling force and transfer sensitivity of the transfer recording layer (3)
, A wax, a silicone resin or the like may be added. Ma
In addition, silica and aluminum
Add fine fillers such as iron, clay and calcium carbonate
It is also possible. Furthermore, the dispersibility of the color pigment is improved.
Above, the purpose of printing and coating suitability of the thermal transfer recording layer (3)
Then, a dispersant, a surfactant and the like may be added. these
The amount of addition does not impair the original performance of the thermal transfer recording layer (3).
It is appropriately selected within a range. Thermal transfer recording layer (3) is preferred
Or the above-mentioned coloring pigment and binder resin in a suitable solvent.
Or fluorescent additives and other additives to dissolve each component.
Is dispersed to prepare an ink for the thermal transfer recording layer, and
It is formed by coating and drying on the support. Thermal transfer recording
The thickness of the layer (3) is desirably 0.2 to 1.0 μm. film
If the thickness is less than 0.2 μm, it is difficult to obtain a sufficient concentration.
In addition, if it exceeds 1.0 μm, the heating part of the thermal head
It is difficult to transfer according to the minute, and the gradation reproducibility is inferior.
Become. Further, a thermal transfer recording layer (3) of the support (2) is provided.
Use a thermal head to apply heat from the
When transferring the thermal transfer recording layer (3) onto the sheet,
The thermal head is attached to the support (2)
To prevent (1) from interfering with the smooth running,
The thermal transfer recording layer (3) of the support (2) is not provided
It is desirable to provide a back coat layer (4) on the side
(See FIG. 2). Used for such a back coat layer (4)
Materials used are nitrocellulose, polyester
Silicone oil for resin, acrylic resin, vinyl resin, etc.
Included or silicon-modified resin
be able to. In addition, in order to improve heat resistance,
Agents may be used in combination. When providing the back coat layer (4)
Is preferably about 0.1 to 4 μm. As above
To form an image using a thermal transfer recording medium (1)
As the transparent image receiving sheet to be used, polyester
System, polyethylene naphthalate film, polyvinyl chloride
Film, polypropylene film, triacetyl cellulose
Plastic film such as roulose film, or
Image receiving layer coated on plastic film
And the like. Thermal transfer recording medium of the present invention as described above
And the floor by area gradation using the image receiving sheet as described above.
Means for applying thermal energy used to obtain tone image representation
Can use any of the conventionally known applying means.
Coming, by controlling the heat energy, the gradation
Images can be obtained.

[0009]

Next, the present invention will be described more specifically with reference to examples. In the following, “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 ... 5 parts Butyral resin (3000-1 made by Sekisui Chemical Co., Ltd .: softening point about 70 ° C) ... 5 parts Methyl ethyl ketone ... 62 parts Toluene ... 28 parts (Magenta ink) Carmine 6B ... 5 parts Butyral resin (Sekisui 5 parts Methyl ethyl ketone 62 parts Toluene 28 parts (yellow ink) Disazo yellow 5 parts Butyral resin (Sekisui Chemical 3000-1: softening point about 70 ° C.) 5 parts Methyl ethyl ketone: 62 parts Toluene: 28 parts The ink for a thermal transfer recording layer of the above formulation is applied to a 5.4 μm-thick polyethylene terephthalate film having a heat-resistant treatment on the back surface to a dry film thickness of 0.5 μm. After drying, the thermal transfer recording medium of the present invention was obtained. The thermal transfer recording layer surface of the obtained cyan thermal transfer recording medium and an image receiving sheet provided with an image receiving layer on the easy-adhesive surface of a 100 μm transparent easy-adhesive polyester film are overlapped, and the thermal head is used to heat the heat-generating portion of the thermal head. A cyan image with an appropriate area gradation was obtained. 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. At the same time, as a result of several tests of resins having different softening points, only a resin having a softening point of 40 to 150 ° C. was able to form a stable gradation image. The maximum transmission density of each color of the image according to the above prescription was 1.0 for cyan, 1.2 for magenta, and 0.4 for yellow.
Was usable enough. When the amount of the pigment added was halved, the maximum transmission densities were 0.7, 0.8, and 0.3, respectively, and an image was formed, but the density was marginal. Further, those having the pigment addition amount reduced to 1/3 had the maximum transmission densities of 0.5, 0.6, and 0.2, respectively, and an image was formed, but the density was insufficient. Further, the image formed on the transparent resin having the adhesive layer can be used as a seal, and no fading was observed even after one year of outdoor use. Example 2 First, an ink composition for a thermal transfer recording layer having the following composition was prepared. (Cyan ink) Phthalocyanine blue ... 5 parts Butyral resin (3000-1 manufactured by Sekisui Chemical Co., Ltd .: softening point about 70 ° C) ... 5 parts Ultraviolet light-emitting fluorescent agent (ZnS: Cu) ... 2 parts Methyl ethyl ketone ... 60 parts Toluene ... 28 parts ( Magenta ink) Carmine 6B 5 parts Butyral resin (3000-1 manufactured by Sekisui Chemical Co., Ltd .: softening point about 70 ° C) 5 parts Ultraviolet light emitting fluorescent agent (ZnS: Cu) 2 parts Methyl ethyl ketone 60 parts Toluene 28 parts (yellow Ink) Disazo Yellow 5 parts Butyral resin (3000-1 manufactured by Sekisui Chemical Co., Ltd .: softening point about 70 ° C.) 5 parts Ultraviolet light emitting fluorescent agent (ZnS: Cu) 2 parts Methyl ethyl ketone 60 parts Toluene 28 parts Thermal transfer of the above formula 5.4-μm-thick polyethylene whose recording layer ink is heat-treated on the back side Lev tallate film, dry film thickness was obtained a thermal transfer recording medium of the present invention was applied and dried so that the 0.5 [mu] m. Next, 100
Perform pattern printing on the easy-adhesion surface of the μm transparent easy-adhesion polyester film using the following ultraviolet-emitting fluorescent ink,
An image receiving sheet including a security printing layer was obtained. (Ultraviolet light-emitting fluorescent ink) Acrylic resin (BR60 manufactured by Mitsubishi Rayon) 20 parts Ultraviolet light-emitting fluorescent agent (ZnS: Cu) 10 parts Methyl ethyl ketone 35 parts Toluene 35 parts The surface of the thermal transfer recording layer of the obtained cyan thermal transfer recording medium The transparent image-receiving sheet was overlaid, and using a thermal head, a cyan image with an area gradation corresponding to the heat generating portion of the thermal head was obtained. 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. The maximum transmission density of each color of this image was 1.0 for cyan, 1.2 for magenta, and 0.4 for yellow. Example 3 A color image was formed in the same manner as in Example 2, except that the ink composition for the thermal transfer recording layer was changed as follows. (Cyan ink) Phthalocyanine Blue ... 5 parts of butyral resin (manufactured by Sekisui Chemical Co., 3000-1: a softening point of about 70 ° C.) ... 5 parts of an infrared-emitting fluorescent agents _{(YF 3: Yb + Er)} ... 2 parts Methylethyl ketone 60 parts Toluene 28 parts (Magenta ink) Carmine 6B: 5 parts Butyral resin (3000-1 manufactured by Sekisui Chemical Co., Ltd .: softening point: about 70 ° C.): 5 parts Infrared light-emitting fluorescent agent (YF ₃ : Yb + Er): 2 parts Methyl ethyl ketone: 60 parts Toluene: 28 parts (Yellow ink) Disazo yellow: 5 parts Butyral resin (3000-1 manufactured by Sekisui Chemical Co., Ltd .: softening point: about 70 ° C.): 5 parts Infrared light-emitting fluorescent agent (YF ₃ : Yb + Er): 2 parts Methyl ethyl ketone: 60 parts Toluene: 28 parts < Comparative Example 1> Sublimation transfer type ink composition as ink for thermal transfer recording layer It was adjusted. (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) 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 A thermal transfer recording medium of Comparative Example 1 was obtained by coating and drying on a 4 μm polyethylene terephthalate film so that the dry film thickness became 1.0 μm. Next, 10
Pattern printing was performed on the easy-adhesion surface of the 0-μm-easy-adhesion polyester film using the following ultraviolet-emitting fluorescent ink. (Ultraviolet light-emitting fluorescent ink) Acrylic resin (BR60 manufactured by Mitsubishi Rayon) ... 20 parts Ultraviolet light-emitting fluorescent agent (ZnS: Cu) ... 10 parts Methyl ethyl ketone ... 35 parts Toluene ... 35 parts Further, on the surface on which the pattern is printed with the ultraviolet light-emitting fluorescent ink The following ink for dye receiving layer was applied and dried so as to have a dry film thickness of 4 μm, and then aged at 45 ° C. for 1 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 Thermal transfer recording of the obtained thermal transfer recording medium The layer surface was superimposed on the dye receiving layer surface 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 The following protective layer ink was applied on a polyester film so as to have a dry film thickness of 2 μm, and dried to obtain a protective sheet. (Ink for protective layer) Acrylic resin ... 20 parts UV absorber ... 1 part Methyl ethyl ketone ... 40 parts Toluene ... 40 parts The protective layer surface of the above protective sheet is overlaid on the color image obtained in Comparative Example 1, and the back surface of the protective sheet Heat was applied from the side by a heat roller to transfer the protective layer onto the color image. <Comparative Example 3> In Example 2, the dry film thickness of the ink for the thermal transfer recording layer was changed to 1.2 for each of cyan, magenta and yellow.
A thermal transfer recording medium was prepared and a color image was formed in the same manner as in Example 1 except that the thickness was changed to μm. Comparative Example 4 A thermal transfer recording medium was prepared and a color image was formed in the same manner as in Example 2, except that the ink for the thermal transfer recording layer was changed to the following formulation. (Cyan ink) Phthalocyanine blue 10 parts Polyamide resin (Tomide 560 manufactured by Fuji Kasei Kogyo: softening point about 160 ° C) 10 parts Ultraviolet light-emitting fluorescent agent (ZnS: Cu) 4 parts Isopropyl alcohol 38 parts Toluene 38 parts ( Magenta ink) Carmine 6B 10 parts Polyamide resin (Tomide 560 manufactured by Fuji Kasei Kogyo: softening point of about 160 ° C) 10 parts Ultraviolet light-emitting fluorescent agent (ZnS: Cu) 4 parts Isopropyl alcohol 38 parts Toluene 38 parts (yellow Ink) Disazo yellow 10 parts Polyamide resin (Tomide 560 manufactured by Fuji Kasei Kogyo Co., Ltd .: about 160 ° C. softening point) 10 parts Ultraviolet light-emitting fluorescent agent (ZnS: Cu) 4 parts Isopropyl alcohol 38 parts Toluene 38 parts Example 2, 3 and Comparative Examples 1, 2, 3, and 4 The image, the image gradation, the evaluation of light resistance and security were conducted.

[0010]

[Table 1]

Tonality: 性: The produced color image is faithfully reproduced from the highlight portion to the shadow portion. ×: Reproducibility from highlight to shadow was insufficient. Light fastness: The color image surface was irradiated with a xenon fade meter for 80 hours, and the fading rate was measured. ：: Fading rate of 5% or less ×: Fading rate of 5% or more Security: It was evaluated whether the ultraviolet light-emitting fluorescent agent printed on the image receiving sheet could be observed by black light (wavelength: about 365 nm). ：: Observable ×: Not observable In addition, when the color image obtained in Example 2 was irradiated with black light (365 nm), the light emission of the luminescent fluorescent agent provided in advance on the image receiving sheet and the color image were formed. At this time, it is possible to observe both the emission of the luminescent fluorescent agent and the pattern according to the color image provided at the same time, and it is possible to obtain an image with high security. The color image obtained in Example 3 was subjected to black light (365 nm) and infrared laser light (about 85 nm).
0 nm), the emission of the luminescent fluorescent agent provided beforehand on the image receiving sheet was observed with respect to the black light, and the color image was formed simultaneously with the infrared laser light when the color image was formed. Light emission of the luminescent fluorescent agent in the pattern could be observed, confirming that an image with high security was obtained. Example 4 In Example 2, 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 composed of four primary colors. (Black ink) Carbon black 5 parts Butyral resin (3000-1 manufactured by Sekisui Chemical Co., Ltd .: softening point about 70 ° C.) 5 parts Ultraviolet light emitting fluorescent agent (ZnS: Cu) 2 parts Methyl ethyl ketone 60 parts Toluene 28 parts obtained The obtained image was confirmed to have the same performance as in Example 2. <Embodiment 5> In Embodiment 4, a color image is converted to cyan,
Binary images of characters and barcodes were created in black using three colors, magenta and yellow. The obtained image was able to have black-light (365 nm) reading performance on characters and barcode portions in addition to the performance of Example 1. <Example 6> Using the thermal transfer recording medium obtained in Example 2, an image was formed on the following image receiving sheet. (Construction of Image Receiving Sheet) Each of the following prescription inks was sequentially applied to a 25 μm polyester film and dried to obtain an image receiving sheet in which a release layer and an image receiving layer were sequentially laminated. (Ink for release and protective layer) Acrylic resin ... 20 parts Methyl ethyl ketone ... 40 parts Toluene ... 40 parts (Ink for image receiving layer) Butyral resin ... 10 parts Methyl ethyl ketone ... 45 parts Toluene ... 45 parts Image-formed image receiving sheet for final product Transparent body (resin,
When heat transfer was performed from the back of the image receiving sheet using a heat roller and only the polyester film was peeled off, a good transfer member having a protective layer on the surface was obtained. <Example 7> Using the thermal transfer recording medium obtained in Example 2, an image was formed on the following image receiving sheet. (Construction of image receiving sheet) The following ink for a release layer and ink for a hologram formation layer are sequentially applied to a 25 μm polyester film and dried to obtain a release layer and a hologram formation layer. A hologram was formed using the 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 as a transparent thin film layer on the surface of the hologram forming layer by vapor deposition, 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) Butyral resin ... 10 parts Methyl ethyl ketone ... 45 parts Toluene ... 45 parts The image receiving sheet is superimposed on the final product sheet on which the ultraviolet light emitting fluorescent agent is printed on the surface. When heat transfer was performed to peel off only the polyester film, a good transfer body having a protective layer on the surface could be obtained. The obtained transfer body had a hologram image and a reading performance by ultraviolet rays as a security function, and had high security.

[0012]

According to the present invention, a color pigment and a special binder resin are contained in a thermal transfer recording layer, and the thermal transfer recording layer is thermally transferred onto an image receiving sheet by a thermal head printer to form a gradation image by area gradation. It has become possible to obtain a transparent image with high gradation and high density on a transparent substrate. Further, by incorporating a luminescent fluorescent agent that emits light by ultraviolet light or infrared light, an image having high security can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a thermal transfer recording medium of the present invention.

FIG. 2 is a cross-sectional view of a thermal transfer recording medium according to another embodiment of the present invention.

[Explanation of symbols]

 1 thermal transfer recording medium 2 support 3 thermal transfer recording layer 4 backcoat layer

Claims (3)

[Claims] A thermal transfer recording layer containing a color pigment and a binder resin is provided on a support, the binder resin has a softening point of 40 to 150 ° C., and the thermal transfer recording layer has a thickness of 0.2 to 150 ° C. A thermal transfer recording medium having a range of 1.0 μm, wherein the image receiving sheet or the final transfer target has light transmittance. 2. A thermal transfer recording layer containing a coloring pigment and a binder resin is provided on a support in advance, the binder resin has a softening point of 40 to 150 ° C., and the thermal transfer recording layer has a film thickness of 0.2. An image in which a thermal transfer recording medium having a range of about 1.0 μm is prepared, and the thermal transfer recording layer of the thermal transfer recording medium is thermally transferred onto a light-transmissive image-receiving sheet by using a thermal head printer to form an image by area gradation. An image forming method, wherein at least one of the colors has a density of 0.8 or more. 3. The image forming method according to claim 2, wherein a luminescent fluorescent agent is contained in the thermal transfer recording layer.