JP2014162040A - Thermal transfer apparatus, and thermal transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer apparatus and a thermal transfer method using a thermal transfer sheet using a post-chelating dye ink capable of preventing printed character information and image information from leaking from a thermal transfer sheet without a complicated constitution.SOLUTION: A thermal transfer apparatus transfers ink onto a body to be transferred using a thermal transfer sheet provided with an ink layer on one surface of a substrate layer and provided with a back face layer on the other surface of the substrate layer. The ink layer of the thermal transfer sheet contains a post-chelating dye; the back face layer comprises 2 layers; only a first back face layer disposed on a substrate layer side contains the post-chelating dye and a metal ion-containing compound capable of forming a chelate complex. The chelate complex is formed with the post-chelating dye contained in the ink layer of the thermal transfer sheet, and the metal ion-containing compound contained in the first back face layer exposed by heating means at a take-up part of the thermal transfer sheet having the ink transferred thereto.

Description

  The present invention relates to a thermal transfer apparatus and a thermal transfer method using a thermal transfer sheet having a post-chelate dye, and more specifically, thermal transfer that can prevent leakage of character information and image information printed from a used thermal transfer sheet. The present invention relates to an apparatus and a thermal transfer method.

  2. Description of the Related Art A thermal transfer system that uses a thermal transfer sheet to print information such as characters and images on a transfer medium such as a card is widely used. The thermal transfer sheet has a base material extending in a strip shape, a sublimation ink layer formed on the base material and containing a sublimation dye, and a hot-melt ink layer containing a pigment and the like. In printing using a thermal transfer sheet, ink is transferred to a transfer medium in a pattern corresponding to a desired image to be printed. In this case, a portion of the thermal transfer sheet that has been ink-transferred has ink that has been removed due to transfer to a transfer target in a pattern corresponding to the printed image. For this reason, it is possible to specify a printed image from the thermal transfer sheet that has been ink-transferred. Therefore, when printing information to be concealed such as ID information such as a face photograph or an address on a transfer target using a thermal transfer sheet, it is necessary to pay sufficient attention to the handling of the thermal transfer sheet to which ink has been transferred.

  In order to cope with such a problem, for example, Patent Document 1 proposes a thermal transfer system that adheres the outermost thermal transfer sheet wound around the winding unit to the thermal transfer sheet located inside the outermost thermal transfer sheet. ing. According to the thermal transfer system described in Patent Document 1, it is possible to integrate an ink-transferred thermal transfer sheet that has been wound around a winding unit, thereby printing characters printed from an ink-transferred thermal transfer sheet. Information and image information can be prevented from leaking.

  By the way, in recent years, a so-called post-chelate thermal transfer method that can express the contrast of an image and can realize excellent image durability has been proposed. The post-chelate method is a method in which a thermal transfer sheet containing a dye capable of forming a chelate complex with a specific metal ion is thermally transferred to a transfer target containing a specific metal ion compound in an image receiving layer, This is a method of forming an image by reacting them with energy to form a chelate complex (for example, Patent Document 2 and Patent Document 3). Images formed by this post-chelation method are less likely to cause dye fading and bleeding, and are excellent in light resistance. Therefore, they are beginning to be applied to information recording bodies such as cards as described above.

  However, in the thermal transfer system described in Patent Document 1, the winding unit is integrated with the ink transfer-completed thermal transfer sheet wound around the core (bobbin), so that the ink transfer wound around the core is transferred. When the used thermal transfer sheet is discarded, the core is also discarded. For this reason, the core cannot be used repeatedly, which increases the cost for processing the thermal transfer sheet that has been ink-transferred.

  With respect to such a problem, the present applicant can prevent leakage of printed character information and image information, and can also recycle the core from a thermal transfer sheet that has been ink-transferred. Has proposed. In other words, in a thermal transfer system that transfers ink to a transfer target using a thermal transfer sheet having a base material layer and an ink layer, the ink layer is formed by performing thermal transfer again from the base material side of the used thermal transfer sheet. A thermal transfer system was proposed that made it impossible to identify the pattern of the printed image that had been formed.

  By the way, the above-described post-chelate dye is designed to develop a desired color by forming a chelate complex by reaction after being transferred (i.e., image formation) to a transfer target. Therefore, the color of the ink layer of the thermal transfer sheet before transfer is different from the color of the image after the chelate reaction.

  When an image is formed on a transferred material using such a thermal transfer sheet, a part of the metal ion compound contained in the image receiving layer of the transferred material moves to the thermal transfer sheet side due to the influence of the back trap. Causes a chelate reaction with the dye in the thermal transfer sheet. As a result, in the used thermal transfer sheet, the color of the portion corresponding to the image forming portion is different from the color of the portion corresponding to the portion where the image was not formed. For example, the cyan color of the post-chelate dye is In the case of a magenta color before the chelate reaction, but a cyan color after the chelate reaction, the printed character information and image information remaining on the used thermal transfer sheet is more than that of a normal thermal transfer sheet. Easy to see. Therefore, in a thermal transfer sheet using a post-chelate dye ink, it may be assumed that prevention of leakage of printed character information and image information is insufficient only by the thermal transfer system described above.

Furthermore, in recent years, there has been a demand for an increase in printing speed, and it has been attempted to cope with the increase in printing energy during thermal transfer. However, when the printing energy is increased, the effect of the back trap described above becomes more significant, and thus the printed character information and image information remaining on the used thermal transfer sheet can be more easily recognized.
The thermal transfer system proposed by the present applicant, which makes it impossible to specify the pattern of the printed image formed on the ink layer by performing thermal transfer again from the substrate side of the used thermal transfer sheet, A heating unit (thermal head) for forming an image on the transfer body and a heating unit for performing thermal transfer again on the used thermal transfer sheet are necessary, that is, a plurality of heating units are required, and the thermal transfer system. Are complicated and expensive.

JP 2008-49663 A JP-A-4-89292 Japanese Patent Laid-Open No. 4-29929

  Therefore, the present invention aims to solve the above-described problems, and in the thermal transfer apparatus and thermal transfer method using the thermal transfer sheet using the post-chelate dye ink, printing is not performed without taking a complicated configuration. It is to provide a thermal transfer apparatus and a thermal transfer method capable of preventing leaked character information and image information from leaking from a thermal transfer sheet.

The above object is achieved by the present invention described below. That is, the present invention includes a base material layer, an ink layer provided on one surface of the base material layer, and a back layer provided on a surface opposite to the surface on which the ink layer of the base material layer is provided. In a thermal transfer apparatus that transfers ink to a transfer object using a thermal transfer sheet provided with
The ink layer of the thermal transfer sheet comprises a post chelate dye,
The back layer is composed of two layers, and includes a metal ion-containing compound capable of forming a chelate complex with the post-chelate dye only in the first back layer disposed on the base layer side, and the first back surface The second back layer provided on the layer comprises a lubricant and a binder resin,
The transferred object comprises a metal ion-containing compound capable of forming a chelate complex with the post-chelate dye,
The thermal transfer device is
A delivery section for delivering the thermal transfer sheet;
The heating unit is disposed on the downstream side of the delivery unit and provided on the back layer side of the thermal transfer sheet, and the ink of the ink layer of the thermal transfer sheet is heated by the heating unit with respect to the transfer target. A transfer portion for transferring the ink of the ink layer of the thermal transfer sheet to the transfer target in a pattern;
A post-chelate dye disposed on the downstream side of the transfer portion, winding up the thermal transfer sheet after ink transfer, and included in an ink layer provided on one side of the thermal transfer sheet, and on the other side of the thermal transfer sheet A winding part that is provided and forms a chelate complex with the metal ion-containing compound included in the first back layer exposed by the heating means;
It was set as the structure of the thermal transfer apparatus characterized by providing.

The present invention also includes a base material layer, an ink layer provided on one surface of the base material layer, and a back layer provided on a surface opposite to the surface on which the ink layer of the base material layer is provided. In a thermal transfer method for transferring ink to a transfer object using a thermal transfer sheet provided with
The ink layer of the thermal transfer sheet comprises a post chelate dye,
The back layer is composed of two layers, and includes a metal ion-containing compound capable of forming a chelate complex with the post-chelate dye only in the first back layer disposed on the base layer side, and the first back surface The second back layer provided on the layer comprises a lubricant and a binder resin,
The transferred object comprises a metal ion-containing compound capable of forming a chelate complex with the post-chelate dye,
The thermal transfer method is:
Sending out the thermal transfer sheet,
After the feeding step, the thermal transfer sheet has heating means provided on the back layer side, and the ink in the ink layer of the thermal transfer sheet is heated by the heating means with respect to the transfer object, and the thermal transfer Transferring the ink of the ink layer of the sheet in a pattern to the transfer target;
After the transferring step, the thermal transfer sheet that has been ink-transferred is wound up, and a post-chelate dye included in an ink layer provided on one side of the thermal transfer sheet, and provided on the other side of the thermal transfer sheet, A winding step of forming a chelate complex with the metal ion-containing compound contained in the first back layer exposed by the heating means,
This is a thermal transfer method, which is performed in order.

  According to the present invention, in a thermal transfer apparatus and thermal transfer method using a thermal transfer sheet using a post-chelate dye ink, printed character information and image information can be leaked from the thermal transfer sheet without taking a complicated configuration. Can be easily prevented.

1 is a schematic diagram illustrating a thermal transfer apparatus according to an embodiment of the present invention. It is a schematic diagram of the cross section which shows the example of the thermal transfer sheet used by this invention. It is a perspective view which shows the example of the thermal transfer sheet used by this invention. FIG. 4A is a diagram showing the transfer target 14 having the ink transferred from the thermal transfer sheet 13 in a pattern by the transfer unit of the thermal transfer apparatus of the present invention, and FIG. 4B is the pattern transferred by the pattern. FIG. 5 is a view showing a surface of the thermal transfer sheet 13 on which ink has been transferred on the ink layer 12 side. FIG. 6 is a schematic diagram of a VI-VI cross section of the thermal transfer sheet 13 after ink transfer in FIG. It is a figure which expands and shows the winding part of the thermal transfer apparatus of FIG. It is the schematic diagram of the cross section which expanded a part of thermal transfer sheet wound up by the winding part after ink transfer shown in FIG. A schematic diagram showing the surface of the ink layer in a state where the ink missing portion 12b is generated in the pattern of the thermal transfer sheet by the heating means, and the second back layer is removed at a position corresponding to the pattern, and the first back surface It is the schematic which shows that an ink layer overlaps with the ink layer which has an ink omission part with said heating means in the state which the layer was exposed and was wound up by the winding-up part, and a 12c pattern develops a color.

  A thermal transfer apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a thermal transfer apparatus according to an embodiment of the present invention. The thermal transfer apparatus 1 according to the present invention is disposed on the downstream side of the transfer unit 17, the transfer unit 16 that transmits the thermal transfer sheet 13 in the direction indicated by the arrow R 1, the transfer unit 17 that is disposed on the downstream side of the output unit 16, And a winding unit 21 for winding the thermal transfer sheet 13 on which the ink has been transferred in the direction indicated by the arrow R2. As shown in FIG. 1, the thermal transfer sheet 13 is supplied from a delivery unit 16 in a winding shape, and is wound along a guide roll 15 by a winding unit 21 via a transfer unit 17.

  As shown in FIG. 1, the transfer unit 17 includes a platen roll 19 that supports the transfer target 14, and a heating unit 18 that is provided to face the platen roll 19 with the thermal transfer sheet 13 and the transfer target 14 interposed therebetween. For example, it has a thermal print head. The supplied transfer target 14 is conveyed toward the transfer unit 17. On the other hand, the thermal transfer sheet 13 is sent out from the sending unit 16 toward the transfer unit 17. The heating means 18 is provided on the back layer 11 side of the thermal transfer sheet 13. When the transfer body 14 reaches between the heating unit 18 and the platen roll 19 of the transfer unit 17, the heating unit 18 heats the thermal transfer sheet 13 with a pattern corresponding to a face image or the like while the transfer unit 14 is heated. Press. Accordingly, the ink of the ink layer 12 of the thermal transfer sheet 13 is heated by the heating unit 18 in a predetermined pattern corresponding to a face image or the like, and the ink of the ink layer 12 of the thermal transfer sheet 13 is patterned in a pattern with respect to the transfer target 14. Transcribed.

  The thermal transfer sheet 13 heated by the heating means 18 of the transfer unit 17 has a problem that the pattern is visually recognized as an ink missing portion after the ink layer 12 is transferred to the transfer target 14 in a pattern. In the present invention, the second back layer 11B in the back layer 11 corresponding to the heated pattern is melted or removed by heat, and the first back layer 11A is exposed. Thereafter, when the thermal transfer sheet 13 is wound up by the winding unit 21, the ink layer 12 of the thermal transfer sheet 13 overlapped with the exposed first back layer 11A in a wound state is colored with the exposed pattern. . Since the first back layer 11A contains a metal ion-containing compound capable of forming a chelate complex with a post-chelate dye, the post-chelate included in the ink layer in contact with the metal ion-containing compound at the take-up portion. This is because the dye reacts to form a chelate complex and develops a color. The ink missing portion in the ink layer of the thermal transfer sheet and the color development of the overlapping portion of the first back surface layer 11A and the ink layer in the winding portion are mixed, and the pattern of the ink missing portion is visually recognized. Therefore, it is possible to prevent information from being easily leaked.

The thermal transfer sheet used in the thermal transfer apparatus and thermal transfer method (hereinafter abbreviated as thermal transfer apparatus) according to the present invention includes a base material layer, an ink layer, and two back layers as will be described later.
As shown in the schematic diagram of the cross section of FIG. 2, the thermal transfer sheet 13 used in the above-described thermal transfer apparatus includes a base material layer 10, an ink layer 12 provided on one surface of the base material layer 10, and a base material layer. On the surface opposite to the surface on which the ten ink layers 12 are provided, at least a back layer 11 having a two-layer structure including a first back layer 11A and a second back layer 11B is provided. The ink layer 12 may be provided directly on the base material layer 10, but an adhesive layer (not shown) may be provided between the base material layer 10 and the ink layer 12. Further, this adhesive layer may be provided on the ink layer 12.
Hereinafter, each layer constituting the thermal transfer sheet used in the thermal transfer apparatus according to the present invention will be described.

(Base material layer)
The base material layer 10 constituting the thermal transfer sheet 13 is a layer for supporting an ink layer 12 to be described later, and can be used without limitation as long as it has a certain level of heat resistance and strength known in the art. For example, polyethylene terephthalate film, 1,4-polycyclohexylenedimethylene terephthalate film, polyethylene naphthalate film, polyphenylene sulfide film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, acetic acid Examples thereof include cellulose derivatives such as cellulose, resin films such as polyethylene film, polyvinyl chloride film, nylon film, polyimide film, and ionomer film.

  The base material layer generally has a thickness of about 0.5 to 50 μm, preferably about 3 to 10 μm. The base material layer may be subjected to an adhesion treatment on one side or both sides as necessary. When a dye ink for forming a dye layer containing a sublimable dye is applied as an ink layer on the base material layer, the wettability and adhesiveness of the coating liquid are likely to be insufficient. It is preferable to perform an adhesion treatment on the surface of the material layer. Examples of the above-mentioned adhesion treatment include corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, chemical treatment, plasma treatment, low temperature plasma treatment, primer treatment, grafting treatment, etc. The reforming technique can be applied as it is. Two or more of these treatments can be used in combination.

(Ink layer)
The ink layer 12 is formed by applying and drying a coating liquid in which a post-chelating sublimation dye is dissolved or dispersed in an appropriate binder resin on the base material layer 10 described above. For example, the coating liquid is applied to one surface of the base material layer by a known means such as a gravure printing method, a screen printing method, a reverse roll coating printing method using a gravure plate, and the ink layer is formed by drying. Can be formed. The coating amount of the ink layer is usually 0.2 to 10.0 g / m ² in solid content, and preferably 0.3 to 3.0 g / m ² . As shown in FIG. 3, the ink layer 12 may have a configuration in which a yellow dye ink layer (Y), a magenta dye ink layer (M), and a cyan dye ink layer (C) are repeatedly provided in the surface order. .

As the post-chelate sublimation dye as described above, conventionally known dyes can be used. Examples of such a chelate-forming sublimation dye include JP-A Nos. 59-78893 and 59-109349. And cyan dyes, magenta dyes and yellow dyes which can form at least bidentate chelates, as described in Japanese Patent Application Nos. 2-213303, 2-214719, and 2-203742. . A preferred sublimable dye capable of forming a chelate can be represented by the following general formula.
X ₁ −N = N−X ₂ −G
(Wherein X ₁ represents an aromatic carbocyclic ring in which at least one ring is composed of 5 to 7 atoms or a group of atoms necessary to complete a heterocyclic ring, and is bonded to an azo bond. At least one of the adjacent positions of the carbon atom is a carbon atom substituted with a nitrogen atom or a chelating group, and X ₂ is an aromatic heterocyclic ring in which at least one ring is composed of 5 to 7 atoms, or Represents an aromatic carbocycle, and G represents a chelating group.)

The amount of the post chelate sublimable dye as described above is usually 0.1 to ²⁰ g, preferably 0.2 to 5 g, per 1 m ^{2 of} the base material layer.
There is no restriction | limiting in particular as binder resin which comprises an ink layer, A conventionally well-known thing can be used. Furthermore, conventionally known various additives can be appropriately added to the ink layer.

(Back layer)
The back layer 11 is provided in two layers on the surface opposite to the surface on which the ink layer of the base material layer is provided. The back layer composed of the two layers is provided in the order of the first back layer 11A and the second back layer 11B from the base material layer side, and the post chelate dye and the chelate complex are only applied to the first back layer. The second back layer provided on the first back layer does not contain the above metal ion-containing compound, but contains a lubricant and a binder resin. Is a layer.

As the metal ion-containing compound to be contained in the first back layer, conventionally known compounds can be used, and inorganic or organic salts and metals of divalent and polyvalent metals belonging to Group I and Group VIII. Complexes can be used. For example, the following general formula containing Ni ²⁺ , Cu ⁺ , Co ²⁺ , Cr ²⁺ and Zn ²⁺ :
[M (Q1) k (Q2) m (Q3) n] p ⁺ p (L ⁻ )
(In the formula, M represents a metal ion, Q1, Q2, and Q3 each represent a coordination compound capable of coordination with the metal ion represented by M, L represents a counter anion that can form a complex, and k Represents an integer of 1, 2 or 3, m represents 1, 2 or 0, and n represents 1 or 0. In these, the complex represented by the above general formula is tetradentate or hexadentate. Or the number of ligands of Q1, Q2, and Q3, and p represents 1, 2, or 3). It is desirable to use a metal soap that also has a function. Particularly preferred specific examples of the metal soap include polyvalent metal salts of alkyl phosphates, polyvalent metal salts of fatty acids, metal salts of alkyl carboxylic acids, and the like.

  Although it does not specifically limit as content in the back surface layer of the metal soap which also has a function as said metal ion containing compound or lubricant, 5-80 mass% is preferable with respect to the binder resin mentioned later, 10-70. The mass% is more preferable. Further, from the viewpoint of adjusting the slipperiness of the back layer, it is preferable to use a metal soap and another metal ion-containing compound in combination.

  As the binder resin used for the back layer, the first back layer and the second back layer can be used in common with those conventionally known, and the binder resin used for the first and second back layers is They may be the same or different. Binder resins include, for example, polyester resins, polyacrylate resins, polyvinyl acetate resins, polyurethane resins, styrene acrylate resins, polyacrylate resins, polyacrylamide resins, polyamide resins, and polyether resins. , Polystyrene resins, polyethylene resins, polypropylene resins, polyolefin resins, vinyl resins such as polyvinyl chloride resins and polyvinyl alcohol resins, cellulose resins such as cellulose resins, hydroxyethyl cellulose resins and cellulose acetate resins, polyvinyl acetoacetals Examples thereof include polyvinyl acetal resins such as resins and polyvinyl butyral resins, silicone-modified resins, and long-chain alkyl-modified resins.

  In addition, as the lubricant contained in the second back layer, a phosphate ester surfactant, dimethylpolysiloxane, methylphenylpolysiloxane, polyethylene wax, montan wax, fatty acid amide, fatty acid ester, long chain Aliphatic compounds, low molecular weight polypropylene, block copolymers of ethylene oxide and propylene oxide, perfluoroalkylethylene oxide adducts, sorbitan acid ester compounds, higher alcohols and / or reactants of higher amines and isocyanates, etc. Alternatively, a mixture of two or more types can be used. The addition amount of the above-described lubricant is in the range of 1 to 100 parts by mass, preferably 2 to 50 parts by mass with respect to 100 parts by mass of the binder resin. If the addition amount of the lubricant is less than 1 part by mass, sufficient lubricity with respect to the thermal head may not be obtained, and the thermal transfer sheet may stick to the thermal head and wrinkles of printing may occur. Also, if the amount of lubricant added is too large, when the thermal transfer sheet is wound and stored, it tends to cause problems such as transfer of the dye in the opposite ink layer to the back layer and a decrease in printing quality. .

  In addition to the lubricant contained in the second back layer, the first back layer is made of a metal soap such as a polyvalent metal salt of an alkyl phosphate ester or a metal salt of an alkyl carboxylic acid. One kind or a mixture of two or more kinds such as a condensate of a fatty acid salt and a polyether compound, and a long-chain alkylsulfonic acid sodium salt can be used.

The addition amount of the above-described lubricant is in the range of 1 to 100 parts by mass and 2 to 50 parts by mass with respect to 100 parts by mass of the binder resin for both the first back layer and the second back layer. Is preferred. If the addition amount of the lubricant is less than 1 part by mass, sufficient lubricity with respect to the thermal head may not be obtained, and the thermal transfer sheet may stick to the thermal head and wrinkles of printing may occur. The thickness of the back layer is determined from the viewpoint of thermal conductivity. For the back layer, both the first back layer and the second back layer are coated on one surface of the base material layer by a known printing means. It can be formed by coating and drying. The coating amount of the first back layer is usually 0.05 to 2.0 g / m ² in solid content, preferably 0.2 to 2.0 g / m ² from the viewpoint of thermal conductivity and the like. is there. The coating amount of the second back layer is such that the second back layer corresponding to the pattern heated by the heating means is melted or removed by heat to expose the first back layer. desirably made smaller than the back layer, usually from 0.05 to 1.0 g / m ² in solids, preferably 0.1 to 0.5 g / m ^2.

  The thermal transfer sheet is usually used in a thermal transfer apparatus in a roll form. Therefore, before use of the thermal transfer sheet, the thermal transfer sheet (that is, the thermal transfer sheet is rolled up with the back layer side inside) In some cases, the ink layer inside the sheet and the back layer outside the thermal transfer sheet are in contact with each other. In that case, depending on the storage environment, the metal ion-containing compound in the back layer moves to the ink layer, the post-chelate sublimation dye in the ink layer and the metal ion-containing compound form a complex, and an unused thermal transfer sheet becomes Color may develop. On the other hand, in the present invention, the back layer 11 of the thermal transfer sheet 13 is made into two layers, and only the first back layer 11A arranged on the base material layer 10 side contains the metal ion-containing compound, and the back layer 11 was provided with a second back surface layer 11B not containing a metal ion-containing compound on the outermost surface side. As a result, the ink layer does not come into contact with the back layer containing the metal ion-containing compound in a state in which the thermal transfer sheet before being transferred to the transfer medium by the heating means is rolled up. No color development. That is, in the thermal transfer apparatus and the thermal transfer method, the metal ion-containing compound contained in the back layer is transferred to the ink layer (setback) by winding (sending part) before the ink layer is transferred in a pattern to the transfer target by the heating means. In order to prevent this, the back layer of the thermal transfer sheet to be used has two layers, and the second back layer, which is the outermost surface, does not contain the metal ion-containing compound.

  FIG. 4A is a diagram showing the transfer target 14 having the ink transferred from the thermal transfer sheet 13 in a pattern by the transfer unit of the thermal transfer apparatus of the present invention, and FIG. 4B is the pattern transferred by the pattern. FIG. 5 is a view showing a surface of the thermal transfer sheet 13 on which ink has been transferred on the ink layer 12 side. FIG. 5 is a sectional view taken along line VI-VI of the thermal transfer sheet 13 shown in FIG. As shown in FIG. 4A, the transferred object 14 formed with an image using a post-chelating sublimation dye as the ink is transferred with a predetermined pattern 12a by heating from the heating means 18, and the transferred object is transferred. The metal ion-containing compound in the image receiving layer (not shown) of the body reacts with the transferred post-chelate sublimation dye to form a chelate complex, whereby a desired color is developed (12a ′). For example, even when a cyan dye is used, the color before the chelate complex is formed may be a color close to magenta (red).

  As shown in FIGS. 4B and 5, the ink layer 12 of the thermal transfer sheet 13 that has been subjected to ink transfer includes a portion 12 a in which ink remains without being transferred to the transfer target 14, and a post-chelate sublimation dye. Is transferred to the transfer body 14 and has a portion 12b where the dye density is low (a portion corresponding to a face photograph printed on the transfer body 14). The portion 12b where the dye concentration is low corresponds to the pattern heated and transferred by the heating means 18 described above.

  In the case of a thermal transfer sheet using a normal dye, since the thermal transfer sheet after ink transfer can recognize the pattern only by the density of the ink layer of the thermal transfer sheet as described above, the used thermal transfer sheet is transferred to the transfer target 14. The possibility of leaking information such as printed face photos is low. On the other hand, when thermal transfer is performed using a thermal transfer sheet having an ink layer containing a post-chelate sublimable dye, the metal ion-containing compound contained in the transferred material is transferred to the thermal transfer sheet side by the energy at the time of thermal transfer. A complex is formed with the post-chelate sublimation dye in the layer, and 2b (that is, a portion corresponding to a face photograph printed on the transfer object 14) develops color. Therefore, compared with the case of using a normal dye ink, the thermal transfer sheet using the post-chelate sublimation dye has only a light and dark portion in the portion 12a where the ink remains and the portion 12b where the dye concentration is low. Instead, a difference in hue occurs. As a result, it is easy to recognize information printed on the transfer target 14 from the used thermal transfer sheet, and there is a high possibility that information such as a facial photograph will leak. The thermal transfer apparatus according to the present invention can solve the above problems. Details will be described below.

As shown in FIG. 1, the thermal transfer apparatus according to the present invention includes a winding unit 21 disposed on the downstream side of the transfer unit 17 that performs thermal transfer to a transfer target. The function of coloring in the winding unit 21 will be described in detail with reference to FIG.
In the winding unit 21 of the present embodiment, the thermal transfer sheet 13 is wound so that the back layer 11 of the thermal transfer sheet 13 is positioned outside the ink layer 12. As the winding progresses, the outer diameter of the roll body constituted by the thermal transfer sheet 13 wound by the winding unit 21 increases. As shown in FIG. 6, in the present embodiment, the thermal transfer sheet 13 located on the outermost periphery of the thermal transfer sheet 13 wound around the winding unit 21 is referred to as an outer thermal transfer sheet 13A, and the outer thermal transfer sheet 13A. The thermal transfer sheet 13 wound around the winding unit 21 on the inner side and adjacent to the outer thermal transfer sheet 13A is referred to as an inner thermal transfer sheet 13B. 3, 5, and 6, the base material layer provided between the ink layer 12 and the back surface layer 11 is omitted, and the back surface layer 11 has a two-layer structure, but is illustrated as a single layer for convenience.

  Next, with reference to FIGS. 7 to 8, description will be given of how the thermal transfer apparatus of the present invention can prevent information such as a face image from leaking from the used thermal transfer sheet. FIG. 7 is an enlarged cross-sectional view of a part of the thermal transfer sheet 13 having been subjected to ink transfer shown in FIG. In addition, when the thermal transfer sheet 13 is wound around the winding unit 21, the wound thermal transfer sheet 13 is actually curved along the roll surface of the winding unit 21, but in FIG. The thermal transfer sheet 13 is drawn ignoring the state. In FIG. 7, the outer thermal transfer sheet 13A and the inner thermal transfer sheet 13B are in contact with each other at the winding unit 21, but for the sake of convenience of explanation, the outer thermal transfer sheet 13A and the inner thermal transfer sheet 13B are disposed. Some gaps are drawn on the.

  As described above, the ink layer 12 of the thermal transfer sheet 13 (hereinafter also referred to as “used thermal transfer sheet”) to which the ink is transferred in a pattern by the transfer unit is not transferred to the transfer target 14 and the ink remains. A second back surface layer corresponding to the position of the portion 12b where the dye concentration is low, comprising the portion 12a and the portion 12b where the post-chelate sublimation dye is transferred to the transfer medium 14 and the dye concentration is low. 11B is in a form in which the first back surface layer 11A is exposed by being melted or removed by a heating means. The inner thermal transfer sheet 13B having the exposed portion (11Aq) and the outer thermal transfer sheet 13A are in contact with each other at the winding unit 21, so that the exposed portion (11Aq) is applied to the ink layer 12 of the outer thermal transfer sheet 13A. When the metal ion-containing compound contained in the first back layer 11A moves, a chelate reaction occurs and color develops (see 12c in FIG. 7).

  The above color development occurs in the state of being wound by the winding unit 21, but before the color development, a chelate complex of a post-chelate dye and a metal ion-containing compound is formed by the heating means 18, and the thermal transfer sheet Since the ink layer is colored with the predetermined pattern 12b, the predetermined pattern and the color pattern 12c at the winding portion are mixed, and the ink layer after being transferred by the heating means of the thermal transfer sheet is used. The predetermined pattern, for example, information such as a face photograph can be read and prevented from leaking.

  The above color mixture exists not only in the pattern, that is, in the shape, but also in the hue and shading, making it difficult to read the information of the predetermined pattern 12b. Referring to FIG. 7, the portion where the ink layer 12 is transferred by the heating device and the dye density is low, that is, the ink missing portion 12b is, for example, a light cyan color when the ink layer 12 develops cyan. (S). That is, the portion 12a of the ink layer before being heated and transferred has a magenta hue (T), and when the ink layer is transferred, the metal ion-containing compound contained in the transfer target is transferred to the thermal transfer sheet side. This is because the color shifts to cyan. Then, only the second back layer of the back layer of the thermal transfer sheet is melted or removed by heat by the heating means, so that the first back layer is exposed, and then the exposed first first layer is taken up by the winding unit 21. The metal ion-containing compound migrates from the back layer to the ink layer 12. In the ink missing portion 12b where the metal ion-containing compound has migrated, the color changes from light cyan (S) to dark cyan (U).

  Further, in the case where the portion where the metal ion-containing compound has transferred is the portion 12a of the ink layer before being transferred by heating, the hue changes from magenta hue (T) to light cyan (V). This light cyan color (V) becomes a lighter cyan color than the light cyan color (S) in the ink missing portion 12b. In this way, the thermal transfer sheet transferred by the heating means and wound by the take-up unit is very difficult to read because the information transferred from the ink layer contains a mixture of hues and shades. , Information leakage can be prevented.

  FIG. 8A is a schematic diagram showing the surface of the ink layer in a state where the ink missing portion 12b is generated in the pattern of the thermal transfer sheet by the heating means. In FIG. 8A, for easy understanding, the pattern of the ink missing portion 12b is indicated by a solid surrounded by a quadrilateral, a triangle, and a circular outer shape. On the back side of the thermal transfer sheet in the state shown in FIG. 8 (1), the second back layer is removed at the location corresponding to the pattern, the first back layer is exposed, and is wound by the winding unit. In this state, the ink layer overlaps with the ink layer having the ink missing portion by the heating means, and the ink layer is colored in the pattern 12c shown in FIG. As a result, the pattern of the ink missing portion 12b of the ink layer partially overlaps with the color pattern of 12c, and the difference in hue and shade are mixed so that the pattern information of the ink missing portion 12b is read. Can be prevented.

  In addition, a transfer object used in the thermal transfer apparatus of the present invention can be prepared by providing an image receiving layer on a substrate, for example. As a material for forming an image receiving layer, that is, a layer capable of receiving an image, a polymer material such as polyvinyl chloride resin, polyester resin, polyvinyl acetal resin, polyvinyl butyral resin, epoxy resin, acrylic resin is used. The image-receiving layer preferably contains a metal ion-containing compound that can be chelated with the heat-transferred post-chelate dye.

  Examples of the chelateable metal ion-containing compound include inorganic or organic salts and metal complexes of metal ions, and among them, salts and complexes of organic acids are preferable. Examples of the metal include monovalent and polyvalent metals belonging to Groups I to VIII of the Periodic Table. Among them, Al, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sn, Ti And Zn are preferable, and Ni, Cu, Cr, Co and Zn are particularly preferable. Specific examples of the metal ion-containing compound (metal source) include Ni2 +, Cu2 +, Cr2 +, Co2 + and aliphatic salts such as acetic acid and stearic acid, or aromatic carboxylic acid salts such as benzoic acid and salicylic acid. Is mentioned.

In addition, the complex represented by the following general formula can be preferably used because it can be stably added to the image receiving layer and is substantially colorless.
General Formula [M (Q1) x (Q2) y (Q3) Z] p + p (L-)
In the above formula, M represents a metal ion, preferably Ni2 +, Cu2 +, Cr2 +, Co2 +, or Zn2 +. Q1, Q2, and Q3 each represent a coordination compound capable of coordinating with a metal ion represented by M, and may be the same or different from each other. These coordination compounds can be selected from, for example, coordination compounds described in Chelate Science (5) (Nan Edo). L- represents an organic anion group, and specific examples include a tetraphenyl boron anion and an alkylbenzene sulfonate anion. x represents an integer of 1, 2 or 3, y represents 1, 2 or 0, and z represents 1 or 0. In these, the complex represented by the above general formula is tetradentate or hexadentate. It is determined by the coordination or by the number of ligands of Q1, Q2 and Q3. p represents 1 or 2. Specific examples of this type of metal source include those exemplified in US Pat. No. 4,987,049.

These post-chelate dyes are easily transferred from the dye layer to the image-receiving layer with a small amount of sublimation heat during image formation, and react with metal ion-containing compounds in the image-receiving layer to become chelate dyes, immobile and weather resistant. It becomes an excellent and strong pigment.
Although the metal ion-containing compound described above has been described as being contained in the image receiving layer, the same metal ion-containing compound contained in the first back layer can be used.

In addition to the above-described polymer material and metal ion-containing compound, the image-receiving layer contains, as additives, an antioxidant, a UV absorber, a light stabilizer, a filler (inorganic fine particles, organic resin particles), and a material. Also good. Examples of the sensitizer include a plasticizer and a thermal solvent.
The means for forming the image receiving layer is the same as that described for the ink layer, and the image receiving layer can be formed by applying a coating liquid and drying by a known means. The coating amount of the image receiving layer is usually 0.1 to 20.0 g / m ² in solid content, and preferably 0.2 to 5.0 g / m ² .

Next, the present invention will be described more specifically with reference to examples. Hereinafter, unless otherwise specified, parts or% is based on mass.
Example 1
On one side of the base layer of the polyethylene terephthalate film having a thickness of 6 μm which has been subjected to the easy adhesion treatment, the coating liquid 1 for the back layer having the following composition is applied at a rate of 0.7 g / m ^{2 in} terms of solid content. The first back layer was formed by coating and drying. Next, on the first back layer, the back layer coating liquid 2 having the following composition is applied and dried so that the thickness is 0.3 g / m ^{2 in} terms of solid content, and then dried. The back layer was formed.

<Back layer coating liquid 1>
-Polyvinyl butyral resin (hydroxyl value 20% by mass) 6.00 parts (# 3000-4, manufactured by Denki Kagaku Kogyo Co., Ltd.)
Polyisocyanate (solid content: 100% by mass, NCO = 17.3% by mass) 8.00 parts (Bernock D750-45, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Zinc stearyl phosphate (LBT-1830 purification, manufactured by Sakai Chemical Industry Co., Ltd.) 3.00 parts ・ Zinc stearate (SZ-PF, manufactured by Sakai Chemical Industry Co., Ltd.) 3.00 parts ・ Filler (Microace P) -3, manufactured by Nippon Talc Kogyo Co., Ltd.) 1.50 parts ・ Polyethylene wax (melting point: 110 to 118 ° C., average particle size: 10 μm) 3.00 parts (Polywax 3000, manufactured by Toyo Petrolite Co., Ltd.)
・ Methyl ethyl ketone 12.58 parts ・ Toluene 59.92 parts

<Back layer coating liquid 2>
Polyvinyl butyral resin (ELEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 2.0 parts Polyisocyanate (solid content 100% by mass, NCO = 17.3% by mass) 9.2 parts (Bernock D750-45, Dainippon Ink & Chemicals, Inc.)
・ Phosphate lubricant (Pricesurf A208N, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.3 parts ・ Filler (Microace P-3, manufactured by Nippon Talc Kogyo Co., Ltd.) 0.3 parts ・ Methyl ethyl ketone 43.6 parts・ Toluene 43.6 parts

In addition, a yellow dye layer coating liquid, a magenta dye layer coating liquid, and a cyan dye layer coating liquid having the following compositions are respectively surface-sequentially arranged in this order on the other surface (easy adhesion treatment surface) of the base material layer. The film was coated so that the thickness of the toner was 1.0 g / m ^{2 in} terms of solid content, and dried to obtain a thermal transfer sheet having three color layers of yellow, magenta, and cyan. (See Figures 2 and 3)

・ポリビニルアセタール ５．５部
（デンカブチラールＫＹ−２４、電気化学工業（株）製）
・メチルエチルケトン ７０．０部
・トルエン ２０．０部 <Coating solution for yellow dye layer>
Yellow dye (post chelate dye compound Y-1 of the following formula) 3.0 parts

・ 5.5 parts of polyvinyl acetal (Denkabutyral KY-24, manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ Methyl ethyl ketone 70.0 parts ・ Toluene 20.0 parts

・ポリビニルアセタール ５．５部
（デンカブチラールＫＹ−２４、電気化学工業（株）製）
・メチルエチルケトン ７０．０部
・トルエン ２０．０部 <Coating liquid for magenta dye layer>
Magenta dye (post chelate dye compound M-1 of the following formula) 3.0 parts

・ 5.5 parts of polyvinyl acetal (Denkabutyral KY-24, manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ Methyl ethyl ketone 70.0 parts ・ Toluene 20.0 parts

・ポリビニルアセタール ５．５部
（デンカブチラールＫＹ−２４、電気化学工業（株）製）
・メチルエチルケトン ７０．０部
・トルエン ２０．０部 <Cyan dye layer coating solution>
-Cyan dye (post-chelate dye compound C-1 of the following formula) 3.0 parts

・ 5.5 parts of polyvinyl acetal (Denkabutyral KY-24, manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ Methyl ethyl ketone 70.0 parts ・ Toluene 20.0 parts

  The thermal transfer sheet of Example 1 described above is a condition that the back layer has a two-layer structure and contains a metal ion-containing compound that is a zinc compound only in the first back layer on the base material layer side. The thermal transfer sheet of Example 1 was rolled up on a plastic core attached to an SP75plus card printer manufactured by Nippon Data Card Co., Ltd., and prepared as a delivery unit 16 shown in FIG. A thermal head mounted on the card printer is used as a heating unit 18 from the delivery unit 16 via a guide roll 15, and a transfer target having the following conditions is provided between the thermal head and the platen roll 19. 14 is transferred between the thermal head and the platen roll, the thermal transfer sheet and the transfer target are overlapped and pressed, and heated with a pattern corresponding to the face image by the thermal head, and the face is applied to the image receiving layer of the transfer target. The image was printed.

(Preparation of transfer object)
The image receiving layer coating solution having the following composition is coated on a commercially available vinyl chloride card by wire bar coating so as to have a ratio of 4.0 g / m ^{2 in} terms of solid content, and dried to be transferred. The body was made.
<Coating liquid for image receiving layer>
・ Vinyl chloride vinyl acetate copolymer (manufactured by Denki Kagaku Kogyo) 50 parts ・ Metal ion compound of the following formula 50 parts

  A printed matter having a face image was obtained at the transfer portion 17 having the heating means 18 by the thermal head. This print was of high quality with a clear photographic tone. Further, the thermal transfer sheet 13 having been transferred with the pattern corresponding to the face image is conveyed through the guide roll 15, wound up by the winding unit 21, and left at room temperature (25 ° C.) for one day. . Thereafter, when the ink layer 12 of the thermal transfer sheet that has been rolled up is observed, the second back layer is removed at the position corresponding to the pattern 12b corresponding to the face image on the back side of the thermal transfer sheet. The back layer is exposed, wound by the winding unit, and overlapped with the ink layer having the ink missing portion by the heating means, and the ink layer is colored in the pattern 12c shown in FIG. 8 (2). As a result, the pattern of the ink missing portion 12b of the ink layer partially overlaps with the color development pattern of 12c, and the difference in hue and lightness / darkness are mixed. It was possible to prevent information from being read.

(Comparative Example 1)
In the thermal transfer sheet prepared in Example 1 above, the back layer was changed to the back layer coating solution 3 having the following composition instead of 2 layers, and the thickness was 0.7 g / m ^{2 in} terms of solid content. The back layer was formed by coating and drying. Otherwise, in the same manner as in Example 1, a thermal transfer sheet having dye layers of three colors of yellow, magenta and cyan was obtained.
<Back layer coating liquid 3>
-Polymethylmethacrylate (BR-85 manufactured by Mitsubishi Rayon Co., Ltd.) 11.1 parts-Melamine aldehyde condensate (Eposter S, manufactured by Nippon Shokubai Co., Ltd.) 2.9 parts-Polyester resin (Elitel UE-3200, Unitika ( Co., Ltd.) 0.3 part ・ Toluene 0.6 part ・ Methyl ethyl ketone 79.2 parts

  As in Example 1, the thermal transfer sheet of Comparative Example 1 was rolled up on a plastic core attached to an SP75plus card printer manufactured by Nippon Data Card Co., so as to form a roll, and used as a delivery unit 16 shown in FIG. Prepared. The thermal head mounted on the card printer is used as the heating means 18 from the delivery section 16 via the guide roll 15 and between the thermal head and the platen roll 19, the same conditions as in the first embodiment. The transfer target 14 is transported, the thermal transfer sheet and the transfer target are overlapped and pressed between the thermal head and the platen roll, and heated with a pattern corresponding to the face image by the thermal head, so that the transfer target A face image was printed on the image receiving layer.

  In Comparative Example 1, a printed matter having a clear photo-like high-quality face image was obtained. The thermal transfer sheet 13 having been transferred with a pattern corresponding to the face image was conveyed through the guide roll 15, wound up by the winding unit 21, and left at room temperature (25 ° C.) for 1 day. Thereafter, when the ink layer 12 of the thermal transfer sheet that has been rolled up is observed, the portion corresponding to the pattern 12b corresponding to the face image described above is an ink missing portion, and the difference between the portion adjacent to the portion and the hue as well as the light and shade Has occurred and can be recognized, and there has been a problem that the face photograph leaks.

DESCRIPTION OF SYMBOLS 1 Thermal transfer apparatus 10 Base material layer 11 Back surface layer 11A 1st back surface layer 11B 2nd back surface layer 12 Ink layer 12a, 12a 'Ink 12b Ink missing part 13 Thermal transfer sheet 13A Outer thermal transfer sheet 13B Inner thermal transfer sheet 14 Transfer object 15 Guide roll 16 Sending part 17 Transfer part 18 Heating means 19 Platen roll 21 Winding part

Claims (2)

A thermal transfer sheet comprising: a base material layer; an ink layer provided on one surface of the base material layer; and a back layer provided on a surface opposite to the surface provided with the ink layer of the base material layer. In a thermal transfer device that transfers ink to a transfer object using
The ink layer of the thermal transfer sheet comprises a post chelate dye,
The back layer is composed of two layers, and includes a metal ion-containing compound capable of forming a chelate complex with the post-chelate dye only in the first back layer disposed on the base layer side, and the first back surface The second back layer provided on the layer comprises a lubricant and a binder resin,
The transferred object comprises a metal ion-containing compound capable of forming a chelate complex with the post-chelate dye,
The thermal transfer device is
A delivery section for delivering the thermal transfer sheet;
The heating unit is disposed on the downstream side of the delivery unit and provided on the back layer side of the thermal transfer sheet, and the ink of the ink layer of the thermal transfer sheet is heated by the heating unit with respect to the transfer target. A transfer portion for transferring the ink of the ink layer of the thermal transfer sheet to the transfer target in a pattern;
A post-chelate dye disposed on the downstream side of the transfer portion, winding up the thermal transfer sheet after ink transfer, and included in an ink layer provided on one side of the thermal transfer sheet, and on the other side of the thermal transfer sheet A winding part that is provided and forms a chelate complex with the metal ion-containing compound included in the first back layer exposed by the heating means;
A thermal transfer apparatus comprising: A thermal transfer sheet comprising: a base material layer; an ink layer provided on one surface of the base material layer; and a back layer provided on a surface opposite to the surface provided with the ink layer of the base material layer. In a thermal transfer method of transferring ink to a transfer medium using
The ink layer of the thermal transfer sheet comprises a post chelate dye,
The back layer is composed of two layers, and includes a metal ion-containing compound capable of forming a chelate complex with the post-chelate dye only in the first back layer disposed on the base layer side, and the first back surface The second back layer provided on the layer comprises a lubricant and a binder resin,
The transferred object comprises a metal ion-containing compound capable of forming a chelate complex with the post-chelate dye,
The thermal transfer method is:
Sending out the thermal transfer sheet,
After the feeding step, the thermal transfer sheet has heating means provided on the back layer side, and the ink in the ink layer of the thermal transfer sheet is heated by the heating means with respect to the transfer object, and the thermal transfer Transferring the ink of the ink layer of the sheet in a pattern to the transfer target;
After the transferring step, the thermal transfer sheet that has been ink-transferred is wound up, and a post-chelate dye included in an ink layer provided on one side of the thermal transfer sheet, and provided on the other side of the thermal transfer sheet, A winding step of forming a chelate complex with the metal ion-containing compound contained in the first back layer exposed by the heating means,
A thermal transfer method, which is performed in order.

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