JPS60183185A - Thermal transfer sheet for multicolor image - Google Patents

Abstract

PURPOSE:To obtain clear multicolor images having high density and free of misregistration of colors, by a method wherein a combination of leuco dye layers capable of forming different colors is provided as a repeating unit, and the light transmittance of at least one of the layers is set to be not higher than 70%. CONSTITUTION:Leuco dye layers (a), (b), (c), (d) for yellow, magenta, cyan and black colors, a color developer layer (e) and a layer X with a light transmittance of not higher than 70% are provided to produce a thermal transfer sheet, wherein a combination of the leuco dye layers (a)-(d) arranged in the direction of the arrow is provided as a repeating unit. The thermal transfer sheet can be produced by applying respective leuco dye liquids and a color developer liquid as inks to a base such as a papers, synthetic paper and a plastic film by letterpress printing or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention utilizes a color reaction between a leuco dye and a color developer to obtain a multicolor image.

Furthermore, the present invention relates to a thermal transfer sheet 1- for multicolor images, which can perform multiple transfers by using the same thermal transfer sheet in combination with the receiving sheet 1-.

[Prior art]

Conventionally, a method of obtaining a multicolor recorded image using a color reaction between a leuco dye and a color developer is known, but in this case, a multicolor image is created by recording a plurality of images on a support. Since a heat-sensitive coloring layer is provided and each color is developed in a different color, the number of tones of a colored image is limited, and is limited to two to three colors at most. Also.

According to Japanese Patent Application Laid-Open No. 57-69094, when thermal transfer is performed on paper using a thermal transfer material in which a plurality of thermal inks having different melting points and tones are applied to a support in a mosaic pattern, the heating temperature is changed. By.

A method for obtaining full color images is shown. However, with such a transfer material coated with thermal ink in a mosaic pattern, it is difficult to obtain a clear full-color image, and it is also impossible to obtain a large number of transferred images using the same transfer material.

[Purpose] The present invention provides a heat-sensitive transfer sheet for multicolor images, which is capable of obtaining high-density, clear, full-color multicolor images without color shift, and also capable of obtaining a large number of transferred images. The purpose is to

〔composition〕

According to the present invention, as a first invention, the leuco dye layer is used in combination with a receiving sheet having a color developer layer, and is used in combination with a receiving sheet having a color developer layer. In a thermal transfer sheet in which a combination of color-producing leuco dye layers is configured as a repeating unit, at least one of the leuco dye layers constituting the repeating unit is formed in advance to have a light transmittance of 70% or less. A second invention provides a thermal transfer sheet for multicolor images, which is used in combination with a receptor sheet, and includes a leuco dye layer and a color developer layer that develop different colors for multicolor development. and a combination of a leuco dye layer and a color developer layer that develop different colors is constituted as a repeating unit.

A thermal transfer for multicolor images, characterized in that at least one layer selected from the leuco dye layer and the color developer layer constituting the repeating unit is colored in advance and formed to have a light transmittance of 70% or less. A sheet is provided.

In the first invention, leuco dye layers that develop different colors for multiple colors are provided on the same support, but in this case,
The leuco dye layers that develop different colors form a set, and the set is structured as a repeating unit on the support. Further, in the second invention, a leuco dye layer and a color developer layer that develop different colors for multiple colors are provided on the same support. The leuco dye layer and the developer layer form a set, and the set is configured as a repeating unit on the support.

The multicolor leuco dye layer used in the present invention may be any layer as long as it develops a desired color, but generally a leuco dye layer that develops each color of yellow, magenta, cyan, and black is selected. By using such four leuco dye layers, seven full colors can be easily obtained. That is, each color i of yellow, magenta, cyan, and blank; in addition to being able to obtain each color by using the leuco dye layer that develops color alone, it is also possible to obtain the development of each color by using the leuco dye layer that develops yellow and the leuco dye layer that develops magenta. To obtain blue coloring by combining a leuco dye layer that develops red and yellow colors and a leuco dye layer that develops cyan colors when combined with a leuco dye layer that develops green and cyan colors and a leuco dye layer that develops magenta colors. I can do it.

Next, the thermal transfer sheet of the present invention will be explained with reference to the drawings.

In Figures 1 to 4, a is a leuco dye layer that develops yellow, b is a leuco dye layer that develops magenta, C is a leuco dye layer that develops cyan, and d is a leuco dye layer that develops black. , and e represents a color developer layer, and X represents a layer with a light transmittance of 70% or less.

FIG. 1 shows an example in which the repeating unit is a combination in which leuco dye layers a to d and developer layer e are arranged between leuco dye layers C and d in the direction of the arrow. In Figure 2, each leuco dye layer a to d and a color developer layer e are arranged in a horizontal direction with respect to the direction of the arrow, but the color developer layer e is arranged horizontally with respect to the direction of the arrow.
An example is shown in which the combination placed after d is the repeating unit. Figure 3 shows leuco dye layers a-d in the direction of the arrow.
An example is shown in which the repeating unit is a combination in which are arranged in the horizontal direction. 1 and 2 show an embodiment of the second invention, and FIG. 3 shows an embodiment of the first invention.

The thermal transfer sheet as described above uses each leuco dye liquid and color developer liquid as ink, and is coated on a support (e.g., paper, synthetic paper, plastic film, etc.) by letterpress printing, gravure printing, etc. can be easily created. An example of such a heat-sensitive transfer sheet is shown in Japanese Patent Application No. 58-100686.

In the present invention, when the thermal transfer sheet 1- has a leuco dye layer and a color developer that develop different colors in a set (Figures 1 to 2), At least one layer selected from a leuco dye layer and a color developer is formed in advance into a MIX having a light transmittance of 70% or less. 1st
The figure shows an example in which the leuco dye layer d is a layer X having a light transmittance of 70% or less.

FIG. 2 shows an example in which the color developer layer e is a layer X having a light transmittance of 70% or less.

In addition, in the present invention, when the thermal transfer sheet 1- has a set of leuco dye layers that develop different colors (Fig. 3), the leuco dye layers of the set At least one layer is formed in advance to have a light transmittance of 70% or less. Figure 3 shows the leuco dye layer d with a light transmittance of 70%.
An example of layer X below is shown.

When forming the coating layer X by applying a leuco dye liquid or a color developer liquid corresponding to the layer X with a light transmittance of 70% or less, the thickness of the coating layer may be adjusted. , or light-absorbing additives in the coating solution, such as silica, aluminum silicate, alumina, aluminum hydroxide, magnesium hydroxide.

It can be obtained by adding an inorganic acid such as formalin resin or styrene resin and organic fine powder.

The thermal transfer sheet 1 of the present invention has - a layer X having a light transmittance of 70% or less provided at a predetermined position;
0% or less of the layer
The thermal transfer sheet 1- can be accurately moved to a predetermined position. As a result, a clear color image without color shift can be obtained. FIG. 4 shows an explanatory diagram of detection of layer X.

In FIG. 4, T indicates a thermal transfer sheet 1-, S indicates a photosensor, and L indicates a light source. The photosensor S operates by sensing the light emitted from the light source and transmitted through the heat-sensitive transfer sheet 1'; in this case, the photosensor S is
When the light transmittance of the thermal transfer sheet 1~ is higher than 70%, it senses light and is activated, that is, it is switched on),
On the other hand, when the light transmittance of the heat-sensitive transfer sheet is 70% or less, number 5 is specified so that the first operation is stopped (that is, the switch is turned off). Therefore.

When a layer The thermal transfer sheet drive system stops its operation, stopping movement of the thermal transfer sheet. In this way, the movement of the thermal transfer sheets 1 to 1 is accurately stopped, and the set of leuco dye layers a, b, c, d and developer layer e, which constitute a repeating unit, is set at an accurate position. . Next, after this set of leuco dye layers a, b, c, d and developer layer e is used a predetermined number of times (this number of uses is, for example, the number of times developer layer e is used, (can correspond to the number of uses of a predetermined leuco dye layer), the thermal transfer sheet drive system operates again to move the thermal transfer sheet, and the next light transmittance is 70%.
When the following layer X reaches the position of the photosensor, its movement is stopped and a set of leuco dye layers a, b, c, d and developer layer e forming a new repeating unit is set. Further, when each leuco dye is formed as the detection layer X, each leuco dye layer can be accurately moved to a predetermined position.

The reason why the light transmittance of 1 layer This is because this layer X can be selectively detected.

As the leuco dyes that develop the colors yellow, magenta, cyan, and hyfrac used in the present invention, any of those conventionally used for pressure-sensitive paper and thermal paper can be used, including triphenylmethane-based, fluoran-based, Phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based agents are preferably applied. Specific examples of these leuco dyes are shown below, but of course the present invention is not limited thereto.

Yellow dye: 3.6-simethoxyfluorane, 3-cyclohexylamino-6-chlorofluoran, 3-(P-dimethylaminophenyl)-3-phenylphthalide, etc.

Magenta dye: 3-diethylamino-7,8-benzfluorane, 3-
diethylamino-6-methyl-7-chlorofluorane,
3-di(1-ethyl-2-methylindole)-3-yl-phthalide, 3-diethylamino-6-phenyl-7
-Azafluoran etc.

Cyan dye: 3.3-bis(ρ-dimethylaminophenyl)-phthalide, 3,3-bis(p-dimethylaminophenyl 6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis (P-diethylaminophenyl)-6-dimethylaminophthalide, 2-bis(p
-dimethylaminophenyl) methyl-5-dimethylamino-benzoic acid, 3-(p-dimethylaminophenyl)-3-(p-dibenzylaminophenyl) phthalide, and the like.

Black dye: 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6
-methyl-7-anilinofluorane, 3-diethylamino-7-piperidinofluorane, etc.

In addition, the color developer used in the present invention includes an electron-accepting substance,
For example, phenolic substances, organic acids, salts or esters thereof, etc. are used, and from the viewpoint of practicality, those with a melting point of 200° C. or lower are preferably used. Specific examples of color developers preferably applied in the present invention are shown below. Note that the numbers in parentheses indicate the melting point.

4” terj-butylphenol (98), 4-hydroxydiphenyl ether (84), l-naphthol (98), 2-naphthol (1.21), methyl-
4-hydroxybenzoate (131), 4-hydroxyacetophenone (,109), 2,2'-dihydroxydiphenyl ether (79), 4-phenylphenol (1.66), 4-tert-octylcatechol (109), 2,2'-dihydroxydiphenyl (103), 4,4'-methylenebisphenol (160), 2,2'-methylenebis(4-chlorophenol) (164), 2,2'-methylenebis(4-methyl-6 - cert-butylphenol>
(125), 4,4'-isopropylidene diphenol (156), 4,4'-isopropylidene bis(2
-chlorophenol) (90), 4,4'-isopropylidene bis(2,6-dibromophenol) (172)
, 4.4'-isopropylidene bis(2-ert
-butylphenol) (110), 4,4'-isopropylidene bis(2-methylphenol) (136),
4.

4'-isopropylidene bis(2,6-dimethylphenol) (168), 4.4'-see-butylidene diphenol (119), 4.4'-Secondary-
butylidene bis(2-methylphenol) (142),
4.4'-cyclohexylidene diphenol (is
o), 4,4' cyclohexylidene bis(2-methylphenol) (184), salicylic acid (163), salicylic acid methalyl ester (74) salicylic acid phenacyl ester (110), 4-hydroxybenzoic acid methyl ester (131) , 4-hydroxybenzoic acid ethyl ester (116), 4-hydroxybenzoic acid isopropyl ester (86), 4-hydroxybenzoic acid butyl ester (71), 4-hydroxybenzoic acid isoamyl ester (50), 4-hydroxybenzoic acid Phenyl ester (178), 4-hydroxybenzoic acid benzyl ester (111), 4-hydroxybenzoic acid cyclohexyl ester (119), 5-hydroxysalicylic acid (
200), 5-chlorsalicylic acid (172), 3-
Chlorsalicylic acid (17B), Thiosalicylic acid (164
), 2-chloro-5-nitrobenzoic acid (165), 4-
Methoxyphenol (53), 2-hydroxybenzyl alcohol (87), 2,5-dimethylphenol (7
5), benzoic acid (122), or I~1~ruylic acid (1
07), metatoluic acid (111), paratoluic acid (
181)-orthochlorobenzoic acid (142), metaoxybenzoic acid (200), 2,4-dihydroxyacetophenone (97), resorcinol monobenzoate (
13 5'), 4-hydroxybenzophenone (133
), 2,4-dihydroxybenzophenone (144),
2-naphthoic acid (184), l-hydroxy-2-naphthoic acid (195), 3.4-
Dihydroxybenzoic acid ethyl ester (128), 3,
4-Dihydroxybenzoic acid phenyl ester (189)
, 4-hydroxypropiophenone (15.0), salicyl salicylate (148), phthalic acid monobenzyl ester (IQ7).

1,1-bis(4'-hydroxyphenyl)ethane (
126), 1.1-bis(4'-hydroxyphenyl)propane (130), 1.1-bis(4'-hydroxyphenyl)hexane (111), 1, l-bis(4'-hydroxyphenyl) Butane (120), ■,]-bis(4'-hydroxyphenyl)-2-
Propylpentane (12B), 1.1-bis(4'-hydroxyphenyl)-2-ethylhexane (87), 2.2-bis(4'-hydroxyphenyl)hebutane (iot), 3.3- Bis(4'-hydroxyphenyl)hexane (155), ], J-bis(3'-methyl-4'-hydroxyphenyl)ethane (101) + 1.1-bis(3'-methyl-4'-hydroxy phenyl)propane (94), 1.1-bis(3'-methyl-4'-hydroxyphenyl)butane (135) + 1.1-bis(3'-methyl-4'-hydroxyphenyl)pentane (97) , 1.1-bis(3'-methyl-4'-hydroxyphenyl)hexane (78), 1.1-bis(3'-methyl-4'-hydroxyphenyl)hebutane (85), 2-(3 '-methyl-4'-hydroxyphenyl)-
2-(4'-hydroxyphenyl)propane (120
), 2.2-bis(3'-methyl-4'-hydroxyphenyl)pentane (12g), 2.2-bis(5'-methyl-4'-hydroxyphenyl)hexane (104), 2.2- Bis(3'-methyl-4'-hydroxyphenyl)4-methylpentane (129), 1,1-bis(
3'-methyl-4'-hydroxyphe3,3-bis(
3'-methyl-41-hydroxyphenyl)hexane (90), 5.5-bis(3'-methyl-4'-hydroxyphenyl)nonane (128), 2-(/I'-hydroxyphenyl)-2- (3'
-chloro-4'-hydroxyphenyl)propane (10
1), 2.2-bis(3'I-isopropyl-4'-hydroxyphenyl)propane (97) 2.2-bis(3'-tert-butyl-4'-hydroxyphenyl)propane (117), 2 .2-bis(
3'-chloro-4'-hydroxyphenyl)propane (4).

2-(4'-hydroxy-3'', 5'-dimethylphenyl)-2-'(4'-hydroxyphenyl)propane (127), bis(3'-methyl-5'-ethyl-4'-hydroxyphenyl ) methane (105), 1.1-(3'-methyl-5'-butyl-4'-hydroxyphenyl)butane (to4), 2.2-bis(4-hydroxyphenyl)octane (8
3), bis(4-hydroxyphenylmercap 1~)methane (
55), 1.2-bis(4-hydroxyphenylmercapto) 1
．． 3-bis(4-hydroxyphenylmercapto)propane (82), 1.4-bis(4-hydroxyphenylmercapto)'
,'',π-3..#,'17x=,).1tvhjJ-
) Pentane (98), ■, 6-bis(4-hydroxyphenylmercapto)hexane (166), 1.3-bis(4-hydroxyphenylmercapto)
Acetone (74), 1,'5 nibis(4-hydroxyphenylmercapto-3-oxapentane (93), 1,7-bis(4-hydroxyphenylmercap I~)
l,8-bis(4-hydroxyphenylmercap 1~)
-3,5-dioxaoctane (100), etc.

The leuco dye layer and/or color developer layer used in the present invention includes:
In order to increase the density of the transferred image and to obtain a transferred image of high density and uniform density even after multiple transfers, it is preferable to further contain a porous filler, if necessary. This porous filler has an oil absorption of at least 50IIIQ/
100g (according to JIS K5101 method), preferably 150raQ/100g or more is used. The proportion of the porous filler contained in the leuco dye layer and/or color developer layer is as follows:
The amount is 0.01 to 1 part by weight, preferably 0.03 to 0.5 part by weight. Specific examples of such porous fillers include inorganic and organic fine powders such as silica, aluminum silicate, alumina, aluminum hydroxide, magnesium hydroxide, urea-formalin resin, and styrene resin. .

When providing a leuco dye layer and a color developer layer on a support, the leuco dye and color developer are 1:1 to the support.

Usually 0.1-20g/i, preferably 0.3-10g
/po coating amount (based on dry solids). Further, as a binder for supporting the leuco dye and color developer on the support, it is preferable to contain a resin having a melting point or softening point of 50 to 130°C. In this case, the resin is a thermoplastic resin. Alternatively, any thermosetting material can be used. When considering the heat resistance and heat sensitivity of the transfer sheet, it is preferable to use a resin having a melting point of 130° C. or lower.

It is sufficient from the viewpoint of thermal sensitivity that the resin has a softening point of 130° C. or lower. Specific examples of such resins include the following.

Polystyrene, polypropylene, polystyrene, petroleum resin, acrylic resin, vinyl chloride resin, vinyl acetate resin,
Vinylidene chloride resin, polyvinyl alcohol, cellulose resin, polyamide, polyacetal, polycarbonate, polyester, fluororesin, silicone resin, natural rubber, chloride rubber, butadiene rubber, olefin rubber, phenolic resin, urea resin, melamine resin, epoxy resin,
polyimide etc.

The resins mentioned above can be used in the form of a single polymer, a copolymer, or a mixture of a plurality of resins. The amount of this resin used is in the range of 0.01 to 1 part by weight per 1 part by weight of the leuco dye or color developer. If the amount of this resin is less than 0.01 parts by weight, the layer adhesion to the support will be weakened, making it impossible to support the leuco dye and color developer on the support with sufficient adhesion. If the amount exceeds 1 part by weight, the thermal sensitivity of the product will decrease and the resulting transferred image density will decrease. The amount of resin is O, O per 1 part by weight of leuco dye or color developer.
It is preferable to use S to 0.5 parts by weight in order to obtain uniform image density in multiple transfers.

In the present invention, in order to obtain a multicolor image using the heat-sensitive transfer sheet, a receiving sheet I to
The thermal transfer sheet is overlaid with a light transmittance of 70% or less, and the thermal transfer sheet is accurately moved to a predetermined position using the layer However, a multicolor image may be formed on the receiving sheet by the reaction between the leuco dye and the color developer. In this case, when a heat-sensitive transfer sheet having a leuco dye layer and a color developer layer is used, ordinary paper, synthetic paper, plastic film, etc. are used as the receiving sheet material.

The amount of color developer transferred to the receiving sheet is 1 to 10 parts by weight, preferably 2 to 5 parts by weight, per 1 part by weight of the leuco dye transferred.
It is best to express it in parts by weight. When forming an image in this manner, the total amount of leuco dye and color developer transferred to the support may be about 1 g/d, and a high-density image can be obtained with this amount of transfer. On the other hand, when using a heat-sensitive transfer sheet having only a leuco dye layer, the receiving sheet is a support having a color developer layer provided thereon.

In the present invention, the heat-sensitive transfer sheet is heated in accordance with the color tone information, as described above. For example, when using the thermal transfer sheet of the second invention (Figs. 1 to 2), when the desired color of the recorded image is yellow, magenta, cyan, or black, the color is developed corresponding to each color. The leuco dye layer and the developer layer are heated to cause a transfer reaction between the leuco dye and the developer on the receiving sheet. In this case, the heating order of the leuco dye layer and the color developer layer is arbitrary, and the color developer layer may be heated after the leuco dye layer, or the heating order may be reversed. On the other hand, to obtain a red recorded image, the leuco dye layer that develops a yellow color, the leuco dye layer that develops a magenta color, and the color developer layer are heated. To obtain a green recorded image, the leuco dye layer that develops yellow, the leuco dye layer that develops cyan, and the color developer layer are heated, and the leuco dye layer that develops cyan and the magenta layer to obtain a blue recorded image. The leuco dye layer and developer layer are heated to develop a color. When obtaining the above-mentioned red, green, and blue recorded images, the heating order may be arbitrary. For example, the developer layer may be heated after the two types of leuco dye layers, or the developer layer may be heated after the two types of leuco dye layers are heated. After heating the dye layer, the two leuco dye layers may be heated. In addition, when using the thermal transfer sheet (third) of the first invention, a suitable leuco dye is added as described above so that an image of a desired color can be obtained on the receiving sheet having a color developer layer. It is sufficient to select a layer and perform heat transfer.

〔effect〕

According to the present invention, a clear multicolor image can be formed on a receiving sheet, and a large number of copies can be obtained using the same thermal transfer sheet. In addition, in the case of the present invention, on the heat-sensitive transfer sheet, a leuco dye layer that develops different colors or a leuco dye layer and a color developer layer that develops different colors are formed as a set and repeatedly Because they are formed as a unit, even if the leuco dye layer or developer of one set is consumed, the next set can be used in the same way as the previous one by simply moving the same thermal transfer sheet. This makes it suitable for making a large number of copies. Moreover,
In the case of the present invention, the position (
(Position of leuco dye layer or developer layer on thermal transfer sheet)
Since a layer X with a light transmittance of 70% or less is provided as a means for accurately detecting It is possible to accurately move and set the sheet and obtain clear multicolor images without color shift.

[Brief explanation of the drawing]

FIGS. 1 to 3 are explanatory diagrams of a heat-sensitive transfer sheet used in the present invention. In FIG. 1, each of the leuco dye layers a to d and the color developer layer C are disposed laterally with respect to the direction of the arrow, and the color developer layer e is disposed between each of the leuco dye layers a to d. An example is shown in which a leuco dye layer and d are formed in a layer
Figure 2 is in the direction of the arrow. Each leuco dye layer a-'d and color developer layer e are arranged in the horizontal direction, and the color developer layer e has a structure in which the combinations arranged after the leuco dye layers a-'d are repeated units. In the thermal transfer sheet, an example is shown in which the color developer layer e is formed in the layer X having a light transmittance of 70% or less. FIG. 3 shows that in thermal transfer sheets 1 to 1 which have repeating units of combinations in which leuco dye layers a"d are arranged in a horizontal direction with respect to the arrow direction, the leuco dye layer d has a light transmittance of 70% or less. Fig. 4 is an explanatory diagram of the principle for detecting layer X with a light transmittance of 70% or less. Layer b...
Leuco dye layer C that develops magenta... Leuco dye layer d that develops cyan... Leuco dye layer e that develops black... Color developer layer X... ...Layer with light transmittance of 70% or less■ ...Thermal transfer sheet S ...Photo sensor ...Light source patent applicant Rico Co., Ltd. - Representative patent attorney Toshiaki Ikeura No. 1 Figure 3 Figure 4

Claims (2)

[Claims] (1) A combination of a leuco dye layer that is used in combination with a receptor sheet that has a color developer layer and that develops different colors for multicolor development, and a leuco dye layer that develops the above-mentioned colors. A thermal transfer sheet comprising repeating units, wherein at least one of the leuco dye layers constituting the repeating units is formed in advance to have a light transmittance of 70% or less. Heat transfer sheet. (2) Used in combination with a receptor sheet, having a leuco dye layer and a color developer layer that develop different colors for multicolor development, and a leuco dye layer and developer layer that develop the above-mentioned colors. In a thermal transfer sheet in which the combination with the agent layer is configured as a repeating unit, at least one selected from the leuco dye layer and the color developer layer constituting the repeating unit is formed in advance to have a light transmittance of 70% or less. A heat-sensitive transfer sheet for multicolor images.