JP6051746B2 - Thermal transfer sheet and image forming method - Google Patents

Description

  The present invention relates to a thermal transfer sheet and an image forming method.

  As a long thermal transfer sheet used in image forming apparatuses such as printers and facsimiles, a hot-melt ink layer or sublimation dye layer is provided on one side of the substrate, and a back layer is provided on the other side of the substrate. A thermal transfer sheet provided with is known. According to this thermal transfer sheet, after the transfer target such as the thermal transfer image receiving sheet and the dye layer of the thermal transfer sheet are stacked so as to face each other, the back layer and the heating device such as the thermal head are brought into contact with each other. An image can be formed on the transfer medium by moving the back layer so as to rub while applying energy according to image information.

  As shown in FIG. 4, such a long thermal transfer sheet 100 is usually wound around a supply roller 101 and takes a pair of forms in which an end of winding and a winding roller 102 are fixed, The supply roller 101 and the take-up roller 102 are respectively mounted at predetermined positions in the image forming apparatus. In general, the axial lengths of the supply roller 101 and the take-up roller 102 are longer than the length in the width direction of the thermal transfer sheet 100. The thermal transfer sheet wound up on the supply roller is conveyed to the heat generating portion side of the heating device at the time of image formation, and is wound around a winding roller that is rotated by a drive motor via the heat generating portion of the heating device. That is, the long thermal transfer sheet is sequentially wound around the winding roller from the used portion after image formation.

  By the way, when the slipperiness of the back layer is poor at the time of image formation, the friction coefficient with respect to the heating device of the back layer becomes high, and sticking or printing wrinkles due to the back layer being melted and adhered to the heat generating part of the heating device or the like. Will occur. Therefore, various studies have recently been conducted to improve the lubricity of the back layer, and a back layer containing, for example, phosphate ester, metal soap, silicone oil or the like as a lubricant component has been proposed. For example, Patent Document 1 proposes a thermal transfer sheet in which a phosphate ester is contained in the back layer. Image formation at high speed is possible by imparting good slipperiness to the back layer of the thermal transfer sheet.

  However, when good slipperiness is imparted to the back layer as described above, the coefficient of friction with the dye layer is lowered. When the used thermal transfer sheet is wound around the winding roller, the back layer and the dye layer are wound so that they overlap each other, so if the friction coefficient between the back layer and the dye layer is small, The dye layer that overlaps the back layer slips from the back layer, and winding deviation occurs in the wound thermal transfer sheet. Specifically, among the thermal transfer sheet wound around the winding roller, the thermal transfer sheet present at a position close to the winding roller, that is, the inner portion of the thermal transfer sheet wound around the winding roller, A bamboo shoot-like winding shift that shifts toward one end of the winding roller occurs. This winding deviation can occur particularly noticeably when the used thermal transfer sheet is wound on the winding roller and the winding tension is low. If bamboo winding-like misalignment occurs in the winding roller, it will not only hinder the take-up roller with the used thermal transfer sheet taken up from the image forming apparatus, but in the worst case In some cases, a winding failure may occur during image formation, causing a transfer error of the thermal transfer sheet.

JP 2009-56599 A

  The present invention has been made in such a situation, and a thermal transfer sheet capable of preventing the occurrence of winding misalignment that may occur when the used thermal transfer sheets used for image formation are sequentially wound, and It is a main object to provide an image forming method capable of preventing the occurrence of winding deviation.

The present invention for solving the above problems is a thermal transfer sheet in which a dye layer is provided on one surface of a substrate, and a back layer is provided on the other surface of the substrate, On one surface or on the dye layer, when the thermal transfer sheet is wound up, a detection mark is provided at a position in contact with the back layer, and the detection mark includes alumina particles as inorganic particles, Or calcium carbonate particles , the back layer contains either or both of zinc stearate and zinc stearyl phosphate as a lubricant component, and is based on the total solid mass of the back layer The content of the lubricant component is in the range of 10 mass% to 50 mass% .
Moreover, the thermal transfer sheet of one embodiment is a thermal transfer sheet in which a dye layer is provided on one surface of a base material, and a back layer is provided on the other surface of the base material. Is further provided with a detection mark, and the detection mark contains alumina particles or calcium carbonate particles as inorganic particles.

  The inorganic particles may be inorganic particles having a shape having one or more corners. The inorganic particles may be contained in a proportion of 0.5% by mass or more with respect to the total solid content of the detection mark. Moreover, the particle diameter of the inorganic particles may be in the range of 0.1 μm to 15 μm in terms of primary average particle diameter.

In addition, the present invention for solving the above-described problems includes a thermal transfer sheet in which a dye layer is provided on one surface of a base material and a back layer is provided on the other surface of the base material, and another base material An image forming method for forming an image on a thermal transfer image receiving sheet by using in combination with a thermal transfer image receiving sheet provided with a dye receiving layer on one side of the substrate , the image forming method comprising: When the thermal transfer sheet is wound up on the dye layer, a detection mark is provided at a position in contact with the back layer, and the detection mark contains alumina particles or calcium carbonate particles as inorganic particles. The back layer contains either or both of zinc stearate and zinc stearyl phosphate as a lubricant component, and the content of the lubricant component with respect to the total solid content of the back layer 10 mass% or less Characterized in that it is in the range of 50 wt% or less.

  According to the thermal transfer sheet of the present invention and the image forming method of the present invention, it is possible to prevent the occurrence of winding misalignment that may occur when the used thermal transfer sheets used for image formation are sequentially wound up. . In particular, the occurrence of winding deviation can be prevented even when the conveyance speed during image formation is increased.

It is a schematic sectional drawing which shows an example of the thermal transfer sheet of this invention. It is a schematic sectional drawing which shows an example of the thermal transfer sheet of this invention. It is a schematic sectional drawing which shows an example of the thermal transfer image receiving sheet used with the image forming method of this invention. It is a figure which shows an example of the thermal transfer sheet wound up by the roller for supply, and the end of winding was fixed to the roller for winding. It is a schematic sectional drawing which shows the location corresponding to 1 screen of the thermal transfer sheet used in the Example.

<< Thermal transfer sheet >>
Hereinafter, the thermal transfer sheet of the present invention will be described in detail. The thermal transfer sheet 10 of the present invention has a configuration in which a dye layer 3 is provided on one surface of a substrate 1 and a back layer 5 is provided on the other surface of the substrate 1 as shown in FIGS. Take. And in this invention, the detection mark 4 is further provided on the base material 1, This detection mark contains the alumina particle or the calcium carbonate particle as an inorganic particle, It is characterized by the above-mentioned.

  The thermal transfer sheet 10 of the present invention is not limited to the illustrated form as long as it satisfies the above requirements. For example, when a sublimable dye is used as the dye contained in the dye layer 3, an undercoat layer (not shown) may be provided between the substrate 1 and the dye layer 3. Further, when a hot-melt ink is used as the dye contained in the dye layer 3, a release layer (not shown) may be provided between the base material 1 and the dye layer 3. In any case, a detection mark 4 including alumina particles or calcium carbonate particles as inorganic particles is provided on the substrate 1 directly or indirectly. Hereafter, each structure of the thermal transfer sheet 10 of this invention is demonstrated concretely.

(Base material)
As the base material 1 used for the thermal transfer sheet 10 of the present invention, a conventionally known base material can be appropriately selected and used as long as it has heat resistance and mechanical properties that do not hinder handling. Examples of such a substrate include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyarylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivative, polyethylene, ethylene / vinyl acetate copolymer, polypropylene, polystyrene, and acrylic. , Polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, polyether sulfone, tetrafluoroethylene / perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene / ethylene, tetrafluoro Ethylene / hexafluoropropylene, polychlorotrifluoroethylene, polyvinylidene fluoride Mention may be made of various plastic films or sheets. Each of these materials can be used alone, but may be used as a laminate in combination with other materials. The thickness of the base material 1 can be appropriately set according to the material so that the strength and heat resistance thereof are appropriate, and is generally about 2.5 μm to 100 μm.

  In addition, the base material 1 may be subjected to adhesion treatment on the surface on which the dye layer 3 is formed. By performing the adhesion treatment, adhesion between the base material 1 and the dye layer 3 or an arbitrary layer provided between the base material 1 and the dye layer 3 can be improved.

  Examples of the adhesion treatment include known resin surfaces such as corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, chemical treatment, plasma treatment, low temperature plasma treatment, primer treatment, and grafting treatment. The reforming technique can be applied as it is. Two or more of these treatments can be used in combination.

(Detection mark)
On the substrate 1 constituting the thermal transfer sheet 10 of the present invention, there is provided a detection mark 4 for indicating a starting position when image formation is performed in combination with the thermal transfer sheet 10 of the present invention and the thermal transfer image receiving sheet. .

  When the used thermal transfer sheet used for image formation is wound, the back layer and the dye layer are wound so as to overlap each other. Here, when the friction coefficient between the dye layer and the back layer is small, the dye layer becomes slippery from the surface of the back layer, and the friction coefficient decreases to the extent that the dye layer slips from the surface of the back layer. When the used thermal transfer sheet is sequentially wound around the winding roller or the like, the inner side of the thermal transfer sheet wound around the winding roller or the like is shifted to one end side of the winding roller. A bamboo shoot-like winding slip occurs. In particular, the higher the slipperiness of the back layer, the smaller the coefficient of friction between the dye layer and the back layer, and the greater the frequency and amount of winding slippage.

  Therefore, in the present invention, the detection mark 4 is provided on the substrate 1, and the detection mark 4 contains alumina particles or calcium carbonate particles as inorganic particles. Although not shown, the thermal transfer sheet 10 of one embodiment has a form in which a part of the surface of the alumina particles and calcium carbonate particles protrudes from the surface of the detection mark 4. For convenience of explanation, the detection mark 4 is exaggerated in FIGS.

  According to the thermal transfer sheet 10 of the present invention in which the detection mark 4 is provided on the base material 1, when the used thermal transfer sheet 10 used for image formation is wound around a winding roller or the like, The layer 5 and the detection mark 4 are in contact with each other. The alumina particles and calcium carbonate particles contained in the detection mark 4 play a role of increasing the coefficient of friction with the back layer 5, so that the back layer 5 is used when winding the used thermal transfer sheet used for image formation. The detection mark 4 is prevented from slipping from the surface. As a result, the coefficient of friction between the back layer 5 and the dye layer 3 can be reduced, and the surface of the back layer 5 is taken up when the used thermal transfer sheet 10 used for image formation is wound around a winding roller or the like. Therefore, even in a situation where the dye layer 3 is slippery, the presence of the detection mark 4 prevents the dye layer 3 from slipping from the surface of the back layer 5, thereby preventing the occurrence of winding slip. In other words, the detection mark 4 functions as a stopper that prevents the dye layer 3 from slipping from the surface of the back layer 5.

  In order to prevent wrinkles or breakage in the dye layer during winding of the thermal transfer sheet, it is preferable to reduce the tension applied to the thermal transfer sheet during winding. However, in a conventional thermal transfer sheet having a dye layer, or a thermal transfer sheet having a dye layer and a detection mark, if the tension applied to the thermal transfer sheet is lowered during winding, the thermal transfer sheet is likely to be unrolled. Therefore, in order to prevent wrinkles and breakage, there is a problem that the tension during winding cannot be simply lowered. In the present invention, since the detection mark 4 in contact with the back layer 5 contains alumina particles and / or calcium carbonate particles as described above, thermal transfer is performed during winding to prevent wrinkles and breakage that may occur in the dye layer. Even when the tension applied to the sheet is lowered, the occurrence of winding deviation can be prevented.

  The specific mechanism by which the friction coefficient between the back layer 5 and the detection mark 4 can be increased by alumina particles and calcium carbonate particles as inorganic particles is not always clear at present. However, when the detection mark 4 does not include alumina particles or calcium carbonate particles as inorganic particles, or the detection mark 4 does not include alumina particles or calcium carbonate particles and includes other particles. In some cases, it has been confirmed that the friction coefficient cannot be increased, and it is clear that alumina particles and calcium carbonate particles play a role of increasing the friction coefficient between the back layer and the detection mark 4.

  There is no particular limitation on the position where the detection mark 4 is formed, and the detection mark 4 can come into contact with the back layer 5 when the used thermal transfer sheet 10 of the present invention used for image formation is wound up. What is necessary is just to be provided in the position. For example, as shown in FIG. 1, the dye layer 3 and the detection mark 4 may be provided on the same surface of the base material 1 in the surface order. As shown in FIG. 2, the dye layer provided on the base material 1. 3 may have a configuration in which the detection mark 4 is provided. Moreover, it is not limited to the form shown in figure, Arbitrary layers, for example, in the structure which provided the dye layer 3 and the protective layer which is not shown in figure on the same surface of the base material 1 surface-sequentially, on this protective layer, It can also be set as the structure which provided the detection mark 4. FIG. Although a part of the detection mark 4 may be covered with an arbitrary layer or the like, at least a part of the surface of the detection mark 4 needs to be exposed.

  The shape of the detection mark 4 is not particularly limited as long as it can be detected by a detector such as a sensor. Examples of the shape of the detection mark 4 include a single line, a stripe shape of two or more lines, a square shape, a round shape, and the like. The detection mark 4 may be provided between the adjacent dye layers 3, may be provided on the dye layer 3, and may be provided between any layer and the dye layer or on any layer. However, when the detection mark 4 is provided on the dye layer 3 or an arbitrary layer, the detection mark 4 may be provided in a region that does not affect image formation, for example, in the vicinity of the outer peripheral portion of the dye layer 3 or the like. preferable. Further, since the detection mark 4 indicates the start position of image formation, it is preferable that the detection mark 4 is provided for each length corresponding to one section. For example, when the dye layer 3 is configured to be provided in the surface order, the head position of each dye layer 3, specifically, between the dye layer 3 adjacent to the head dye layer 3 or an arbitrary layer, Alternatively, it is preferably provided on the leading dye layer 3. In the embodiment shown in FIG. 1, detection marks 4 are provided between the dye layers, and in the embodiment shown in FIG. 2, detection marks are provided on the dye layers.

  The detection mark 4 may contain any one of alumina particles and calcium carbonate particles, or may contain both particles. Moreover, you may contain another component with these particles. There is no particular limitation on the other components, and the other components included in the detection mark 4 differ depending on which type of detector the detection mark 4 is detected by. Hereinafter, the description will be made centering on the case where the detection mark 4 is a mark detected by a light transmission type detector. The detection mark 4 is an essential component for increasing the coefficient of friction with the back layer 5. A detection mark 4 that contains particles and / or calcium carbonate particles and can be detected by a conventionally known detector, and can be detected by a detector of a system other than the light transmission type detector. For example, the detection mark 4 detected by a light reflection type detector or the detection mark 4 detectable by a detector of another type can be used.

  When the detection mark 4 is a mark detected by a light transmission type detector, the detection mark 4 includes alumina particles and / or calcium carbonate particles which are essential components, and a color detectable by the detector. Contains material and binder resin.

  Examples of the color material that can be detected by the light transmission detector include carbon black and titanium oxide. Examples of the binder resin include cellulose derivatives such as ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and cellulose acetate butyrate, vinyl such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide. Resin, polyester and the like.

  Hereinafter, the alumina particles and calcium carbonate particles as inorganic particles contained in the detection mark 4 will be described more specifically.

  The shape of the alumina particles and calcium carbonate particles as inorganic particles contained in the detection mark 4 is not particularly limited, but a shape having one or more corners is preferable. By including the alumina particles and calcium carbonate particles having such shapes in the detection mark 4, the friction coefficient between the detection mark 4 and the back surface layer 5 can be further increased, and the back surface layer can be used for high-speed image formation. This is particularly effective when the slipperiness of No. 5 is increased.

  Further, when the shape of the alumina particles and calcium carbonate is the above shape, it is preferable that a portion having one or more corners protrudes from a part of the surface of the detection mark 4. In addition, examples of the shape having one or more corners include polygonal shapes, polyhedrons, and irregular shapes, and shapes having no corners, for example, a shape, a scale shape, and the like have one or more corners. It is not included in the shape having. This does not exclude that the detection mark 4 includes spherical particles or the like, or spherical calcium carbonate particles or the like, and does not exclude one or more corners of the alumina particles, Even when calcium carbonate particles are included in the detection mark 4, the friction coefficient can be increased.

  Since the alumina particles and calcium carbonate particles contained in the detection mark 4 do not have a direct influence during image formation, the particle diameter is not particularly limited, but the primary average particle diameter is less than 0.1 μm. In some cases, depending on the thickness of the detection mark 4, alumina particles and calcium carbonate particles cannot be protruded from the surface of the detection mark 4, and the coefficient of friction between the detection mark 4 and the back layer 5 cannot be sufficiently increased. Cases can arise. If the primary average particle diameter exceeds 15 μm, depending on the thickness of the detection mark 4, the amount of protrusion from the surface of the detection mark 4 increases, and the alumina particles and calcium carbonate particles may fall off the detection mark 4. sell. Considering this point, it is preferable that the alumina particles and calcium carbonate particles contained in the detection mark 4 have a primary average particle diameter in the range of 0.1 μm to 15 μm.

  The content of alumina particles and calcium carbonate particles with respect to the total solid content of the detection mark 4 is not particularly limited, but when the content of alumina particles or calcium carbonate particles is less than 0.5% by mass, the detection mark In some cases, the coefficient of friction between 4 and the back layer 5 cannot be sufficiently increased. Therefore, in consideration of this point, it is preferable that the alumina particles and the calcium carbonate particles are contained at a ratio of 0.5 mass% or more with respect to the total solid content of the detection mark 4. The upper limit of the content is not particularly limited, and may be appropriately set according to the content of an arbitrary component for detecting the detection mark 4.

  The thickness of the detection mark 4 is not particularly limited, but when it is provided on the same surface as the dye layer 3, it is preferable that the thickness of the detection mark 4 is substantially the same as or thicker than the dye layer 3. On the other hand, when the detection mark 4 is provided on the dye layer 3 or an arbitrary layer, when the image is formed so that the dye layer 3 and the dye receiving layer are opposed to each other, an image corresponding to the thickness of the detection mark 4 is formed. At the time of formation, the distance between the dye layer 3 near the detection mark 4 and the dye receiving layer is increased. Therefore, in this case, it is preferable to set the thickness to a range that does not hinder the transfer of the dye of the dye layer to the dye receiving layer, for example, about 0.3 μm to 3 μm.

  There is no particular limitation on the method of forming the detection mark 4 containing alumina particles and / or calcium carbonate particles, and the alumina particles and / or calcium carbonate particles, components for enabling detection by a detector, and as necessary. The coating solution in which the binder resin or the like contained is dispersed or dissolved in a suitable solvent is applied by a conventionally known coating means such as a gravure printing method, a reverse roll coating method using a gravure plate, a roll coater or a bar coater. It can be formed by coating on the substrate 1, or the dye layer 3 or an arbitrary layer, and drying.

(Dye layer)
As shown in FIGS. 1 and 2, a dye layer 3 is provided on one surface of the substrate 1. The thermal transfer sheet 10 in the form shown in FIGS. 1 and 2 has a configuration in which a single dye layer 3 is provided on the base material 1. A dye layer, for example, a yellow dye layer containing a yellow dye, a magenta dye layer containing a magenta dye, and a cyan dye layer containing a cyan dye may be provided in the surface order. In addition to this, a dye layer containing a sublimable dye and a dye layer containing a heat-meltable ink may be provided in a surface sequence on a single continuous substrate.

  The dye layer 3 contains a dye and a binder resin. The dye contained in the dye layer 3 is not particularly limited. For example, when the thermal transfer sheet 10 of the present invention is a sublimation type thermal transfer sheet, the dye layer 3 contains a sublimable dye. Further, when the thermal transfer sheet 10 of the present invention is a thermal melting type thermal transfer sheet, the dye layer 3 contains a hot-melt ink. Hereinafter, the case where the thermal transfer sheet of the present invention is a sublimation type thermal transfer sheet will be mainly described.

<Dye>
As the sublimable dye, those having a sufficient color density and not discolored by light, heat, temperature, etc. are preferable. For example, diarylmethane dyes, triarylmethane dyes, thiazole dyes, merocyanine dyes, pyrazolones Dyes, methine dyes, indoaniline dyes, acetophenone azomethine, pyrazoloazomethine, imidazole azomethine, imidazoazomethine, pyridone azomethine and other azomethine dyes, xanthene dyes, oxazine dyes, dicyanostyrene, tricyanostyrene and other cyano Styrene dyes, thiazine dyes, azine dyes, acridine dyes, benzene azo dyes, pyridone azo, thiophenazo, isothiazole azo, pyrrole azo, pyrazole azo, imidazole azo, thiadiazole azo, triazole azo Azo dye of the disazo, etc., spiropyran dyes, India Linos Piropi run dyes, fluoran dye, rhodamine lactam-based dyes, naphthoquinone dyes, anthraquinone dyes, quinophthalone dyes, and the like. Specifically, red dyes such as MSRedG (manufactured by Mitsui Toatsu Chemical Co., Ltd.), Macrolex Red Violet R (manufactured by Bayer), CeresRed 7B (manufactured by Bayer), Samalon Red F3BS (manufactured by Mitsubishi Chemical), and holon brilliant yellow Yellow dyes such as 6GL (manufactured by Clariant), PTY-52 (manufactured by Mitsubishi Kasei), Macrolex Yellow 6G (manufactured by Bayer), Kayaset Blue 714 (manufactured by Nippon Kayaku Co., Ltd.), Waxoline Blue AP-FW ( ICI), Holon Brilliant Blue SR (Sand), MS Blue 100 (Mitsui Toatsu Chemical), C.I. I. Blue dyes such as Solvent Blue 22 are listed.

<Binder resin>
It does not specifically limit about binder resin, A conventionally well-known binder resin can be selected suitably and can be used. Preferred binder resins include cellulose resins such as ethyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, methyl cellulose, cellulose acetate, and cellulose butyrate, and vinyls such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, and polyacrylamide. Resin, polyester resin, phenoxy resin and the like. Among these, polyvinyl acetal resin and polyvinyl butyral resin can be particularly preferably used from the viewpoints of heat resistance, dye transferability, and the like.

  The sublimable dye is preferably contained in the range of 50% by mass to 350% by mass, preferably 80% by mass to 300% by mass, based on the total solid content of the binder resin of the dye layer 3. When the content of the sublimation dye is less than the above range, the printing density may be lowered, and when it exceeds the above range, the storage stability and the like may be deteriorated.

  The heat-meltable ink contained in the dye layer 3 of the heat-melting type thermal transfer sheet 10 can be appropriately selected from known organic or inorganic pigments or dyes, and has, for example, a sufficient color density. Those which do not discolor or fade due to light, heat, or the like are preferable. The color of the hot-melt ink is not limited to cyan, magenta, yellow, and black, and various colorants can be used.

  Examples of the binder resin contained in the dye layer 3 of the heat melting type thermal transfer sheet include, for example, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, polyethylene, polystyrene, polypropylene, polybutene, petroleum resin, and chloride. Vinyl resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol, vinylidene chloride resin, acrylic resin, methacrylic resin, polyamide, polycarbonate, fluororesin, polyvinyl formal, polyvinyl butyral, acetyl cellulose, nitrocellulose, polyvinyl acetate, poly Isobutylene, ethyl cellulose, polyacetal or the like can be used.

  The hot-melt dye layer 3 may contain microcrystalline wax, carnauba wax, paraffin wax, or the like. Furthermore, Fischer-Tropsch wax, various low molecular weight polyethylene, wood wax, beeswax, whale wax, ibota wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid ester, fatty acid amide and other waxes Ingredients may be included.

(Other ingredients)
In addition to the dye, binder resin, alumina particles as inorganic particles, and calcium carbonate particles, the dye layer 3 may contain other components. Examples of other components include aluminum and molybdenum disulfide, polyethylene wax, silicone oil, phosphate ester, and the like.

  As a method for forming the dye layer 3, the above-described dye, binder resin, and other components contained as necessary may be used, for example, an appropriate solvent such as toluene, methyl ethyl ketone, ethanol, isopropyl alcohol, cyclohexane, dimethylformamide or the like. The coating liquid dispersed or dissolved in is coated on the substrate 1 by a conventionally known coating means such as a gravure printing method, a reverse roll coating method using a gravure plate, a roll coater or a bar coater, and dried. Can be formed. There is no limitation in particular about the thickness of a dye layer, and about 0.1 micrometer-3 micrometers are common.

(Undercoat layer)
When the thermal transfer sheet of the present invention is a sublimation type thermal transfer sheet, an undercoat layer (not shown) is preferably provided between the substrate 1 and the dye layer 3. By providing the undercoat layer, the adhesion between the substrate 1 and the dye layer 3 can be improved, and the dye layer 3 can be prevented from being abnormally transferred during image formation.

  As the resin constituting the undercoat layer, polyester resin, polyvinyl pyrrolidone resin, polyvinyl alcohol resin, hydroxyethyl cellulose, polyacrylate resin, polyvinyl acetate resin, polyurethane resin, styrene acrylate resin, polyacrylamide resin Examples thereof include resins, polyamide resins, polyether resins, polystyrene resins, polyethylene resins, polypropylene resins, polyvinyl chloride resins, polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral, and the like.

  The undercoat layer can also be composed of ultrafine colloidal inorganic pigment particles. This not only prevents abnormal transfer of the dye layer 3 to the thermal transfer image receiving sheet at the time of thermal transfer, but also prevents migration of the dye from the dye layer 3 to the undercoat layer at the time of image formation, to the receiving layer side of the thermal transfer image receiving sheet. Dye diffusion can be performed effectively and the print density can be increased.

  As the colloidal inorganic pigment ultrafine particles, conventionally known compounds can be used. For example, silica (colloidal silica), alumina or alumina hydrate (alumina sol, colloidal alumina, cationic aluminum oxide or its hydrate, suspect boehmite, etc.), aluminum silicate, magnesium silicate, magnesium carbonate, magnesium oxide, oxidation Examples include titanium. In particular, colloidal silica and alumina sol are preferably used. These colloidal inorganic pigment ultrafine particles have a primary average particle size of 100 nm or less, preferably 50 nm or less.

The undercoat layer is a gravure coating method, a roll coating method, a screen printing method, a gravure plate, or a coating solution for the undercoat layer in which the resin exemplified above or colloidal inorganic pigment ultrafine particles are dissolved or dispersed in an appropriate solvent. It can be formed by coating and drying by a conventionally known forming means such as the reverse roll coating method used. The coating amount of the undercoat layer coating solution is preferably from 0.02g / m ² ~1.0g / m ² approximately.

  When the thermal transfer sheet of the present invention is a thermal melting type thermal transfer sheet, a release layer (not shown) is preferably provided between the substrate 1 and the dye layer 3. Examples of the resin forming the release layer include waxes, silicone wax, silicone resin, silicone-modified resin, fluorine resin, fluorine-modified resin, polyvinyl alcohol, acrylic resin, heat-crosslinkable epoxy-amino resin, and heat-crosslinkable alkyd. -Amino resin etc. are mentioned. Further, the release layer may be composed of one kind of resin or may be composed of two or more kinds of resins. The release layer may be formed by using a cross-linking agent such as an isocyanate compound, a catalyst such as a tin-based catalyst, and an aluminum-based catalyst in addition to the releasable resin. The thickness of the release layer is generally about 0.5 μm to 5 μm. The release layer is formed by dissolving or dispersing the resin in a suitable solvent to prepare a release layer coating solution, which is then applied to the substrate 1 by a gravure printing method, a screen printing method or a gravure plate. It can be formed by coating and drying by a conventionally known means such as a reverse coating method using a bismuth.

(Transferable protective layer)
Although not shown, the thermal transfer sheet of the present invention and the thermal transfer sheet 10 used in the image forming method of the present invention have a configuration in which a dye layer 3 and a transferable protective layer are provided in the surface order on a substrate 1. You can also. The transferable protective layer is a layer for imparting various durability to the image. The transferable protective layer may have a multilayer structure or a single layer structure. According to the heat transfer sheet in which the dye layer 3 and the transferable protective layer are provided in the surface order, one thermal transfer sheet can form an image on a transfer target and impart durability to the image. Can be achieved.

  The transferable protective layer can be formed of various resins conventionally known as protective layer forming resins. Examples of the resin for forming the protective layer include polyester resins, polystyrene resins, acrylic resins, polyurethane resins, acrylic urethane resins, resins obtained by silicone-modifying these resins, mixtures of these resins, ionizing radiation curable resins, An ultraviolet blocking resin can be used.

  The main protective layer constituting the transfer protective layer having a single-layer structure or the transfer structure having a multilayer structure usually has a thickness of about 0.5 μm to 10 μm, although it depends on the type of the protective layer forming resin. Is preferred.

  A release layer may be provided between the transferable protective layer and the substrate. As the resin constituting the release layer, polyvinyl alcohol resin, polyacrylate resin, polyvinyl acetate resin, styrene acrylate resin, polyacrylamide resin, polyamide resin, polyether resin, polystyrene resin, Examples thereof include polyethylene resins, polypropylene resins, polyvinyl chloride resins, polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral.

(Back layer)
As shown in FIG. 1, a back layer 5 is provided on the other surface of the substrate 1 to improve heat resistance and lubricity during image formation.

  The back layer 5 can be formed by appropriately selecting a conventionally known thermoplastic resin or the like. As such a thermoplastic resin, for example, polyester resins, polyacrylate resins, polyvinyl acetate resins, styrene acrylate resins, polyurethane resins, polyethylene resins, polypropylene resins, and other polyolefin resins, Polystyrene resin, polyvinyl chloride resin, polyether resin, polyamide resin, polyimide resin, polyamideimide resin, polycarbonate resin, polyacrylamide resin, polyvinyl chloride resin, polyvinyl butyral resin, polyvinyl acetoacetal resin, etc. Examples thereof include thermoplastic resins such as polyvinyl acetal resin, and silicone modified products thereof.

  Moreover, you may add a hardening | curing agent to above-described resin. As the polyisocyanate resin that functions as a curing agent, conventionally known ones can be used without any particular limitation. Among them, it is desirable to use an adduct of an aromatic isocyanate. As the aromatic polyisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, Examples include p-phenylene diisocyanate, trans-cyclohexane-1,4-diisocyanate, xylylene diisocyanate, triphenylmethane triisocyanate, and tris (isocyanatophenyl) thiophosphate, particularly 2,4-toluene diisocyanate and 2,6-toluene diisocyanate. Or, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate is preferable. Such a polyisocyanate resin crosslinks the above-mentioned hydroxyl group-containing thermoplastic resin using the hydroxyl group, thereby improving the coating strength and heat resistance of the back layer.

  Moreover, it is preferable that the back surface layer 5 contains a lubricant component for improving lubricity with a heating device such as a thermal head in addition to the thermoplastic resin. There is no particular limitation on the lubricant component, and conventionally known lubricants such as phosphate ester, metal soap, graphite powder, fluorine-based graft polymer, silicone oil, silicone-based graft polymer, acrylic silicone graft polymer, acrylic siloxane, aryl siloxane, etc. Silicone polymers, fatty acid esters and the like can be appropriately selected and used. Among the above-mentioned lubricant components, phosphate esters and metal soaps can be particularly preferably used in the present invention. In the present invention, since the detection mark 4 contains alumina particles or calcium carbonate particles for increasing the friction coefficient between the detection mark 4 and the back layer 5, the back layer 5 contains a lubricant component. Even when the slipperiness of the back surface layer 5 is improved, it is possible to prevent winding deviation from occurring when the used thermal transfer sheet is wound up.

  Examples of the metal soap include polyvalent metal salts of alkyl phosphates and metal salts of alkyl carboxylic acids. As the polyvalent metal salt of the alkyl phosphate, those known as additives for plastics can be used. The polyvalent metal salt of the alkyl phosphate ester is generally obtained by substituting the alkali metal salt of the alkyl phosphate ester with a polyvalent metal, and various grades are available.

  Examples of the phosphate ester include (1) a phosphoric acid monoester or diester of a saturated or unsaturated higher alcohol having 6 to 20 carbon atoms, and (2) a phosphoric acid monoester of a polyoxyalkylene alkyl ether or polyoxyalkylene alkyl allyl ether. Ester or diester, (3) phosphoric acid monoester or diester of the above-mentioned saturated or unsaturated higher alcohol alkylene oxide adduct (average number of added moles of 1 to 8), (4) alkylphenol having an alkyl group of 8 to 12 carbon atoms Alternatively, phosphoric acid monoester or diester of alkyl naphthol can be used. Examples of the saturated or unsaturated higher alcohol in the above (1) and (3) include cetyl alcohol, stearyl alcohol, oleyl alcohol and the like. Examples of the alkylphenol in the above (3) include nonylphenol, dodecylphenol, diphenylphenol and the like.

  The content of the lubricant component is not particularly limited, but when the content of the lubricant component is less than 5% by mass with respect to the total solid content of the back layer 5, the lubricity of the back layer 5 becomes insufficient and formed. In some cases, the glossiness of the printed image is lowered, and the occurrence of printing wrinkles may occur. On the other hand, when the content of the lubricant component exceeds 50% by mass, scraped scraps of the lubricant are likely to adhere to the thermal head, which may cause poor printing. In consideration of such points, the content of the lubricant component is preferably in the range of 5% by mass to 50% by mass with respect to the total solid content of the back layer 5, and is preferably 10% by mass to 40% by mass. It is particularly preferable that the value falls within the range. By setting the content of the lubricant component within the range of 5% by mass or more and 50% by mass or less with respect to the total solid content of the back surface layer 5, the time required for printing at the time of image formation of the thermal transfer sheet 10 at the time of image formation, Even in the case of 10 seconds / sheet or less, it is possible to prevent printing wrinkles and sticking. Further, due to the presence of alumina particles or calcium carbonate particles contained in the detection mark 4, it is possible to prevent the occurrence of winding deviation even when the used thermal transfer sheet is wound up under the conditions for the required printing time. . Note that the printing time here means printing out one PC size (4 x 6 inches: 4 inches in the printing direction) (the printed material is printed from the point where the thermal head of the printer is heated and the printed material is formed). It means the time required for the process to be discharged to the outside.

The back layer 5 is formed, for example, on the surface of the substrate 1 opposite to the dye layer 3 by applying a coating liquid in which the thermoplastic resin and various additives added as necessary are dispersed or dissolved in an appropriate solvent. Further, it can be formed by applying and drying by a known means such as a gravure printing method, a screen printing method, a reverse roll coating printing method using a gravure plate. The coating amount of the back layer 5 is preferably coated amount after drying is 3 g / m ² or less, and more preferably to ^{0.1g / m 2 ~2g / m 2} .

(Back primer layer)
Further, a back primer layer (not shown) may be provided between the substrate 1 and the back layer 5. The back primer layer is a layer provided in order to improve the adhesion between the substrate 1 and the back layer 5 and is an arbitrary layer. Examples of the back primer layer include polyester resin, polyurethane resin, acrylic resin, polycarbonate resin, vinyl chloride / vinyl acetate copolymer, and polyvinyl butyral resin.

  The thermal transfer sheet 10 of the present invention has been described above. However, the thermal transfer sheet 10 of the present invention can be variously modified without departing from the spirit of the present invention. For example, in the form shown in FIGS. 1 and 2, the detection mark 4 is provided between adjacent dye layers 3 or on the dye layer 3, but a transferable protective layer is provided on the same surface as the dye layer 3. The detection mark 4 may be provided on the transferable protective layer or between the transferable protective layer and the dye layer 3, and the thermal transfer sheet of these forms is also included in the scope of the present invention.

  Further, as shown in FIG. 4, for example, the thermal transfer sheet 10 of the present invention is wound in the image forming apparatus as a pair of forms in which one end is wound around a supply roller and the end of winding and the winding roller are fixed. It can be used by wearing the device.

<< Image Forming Method >>
Next, the image forming method of the present invention will be described. The image forming method of the present invention includes a thermal transfer sheet in which a dye layer is provided on one surface of a substrate and a back layer is provided on the other surface of the substrate, and on one surface of the other substrate. An image forming method for forming an image on a thermal transfer image receiving sheet by using in combination with a thermal transfer image receiving sheet provided with a dye receiving layer, wherein a detection mark is further provided on the substrate of the thermal transfer sheet, The detection mark contains alumina particles or calcium carbonate particles as inorganic particles, and the time required for printing the thermal transfer sheet during image formation is 10 seconds / sheet or less. According to the image forming method of the present invention, it is possible to prevent the occurrence of winding misalignment that may occur when the used thermal transfer sheet is wound up while enabling image formation at high speed. The reason why the occurrence of winding deviation can be prevented is as described in the thermal transfer sheet 10 of the present invention.

(Thermal transfer sheet)
As the thermal transfer sheet used in the image forming method of the present invention, the thermal transfer sheet 10 of the present invention can be used as it is. In the image forming method of the present invention, since the time required for printing the thermal transfer sheet at the time of image formation is defined as 10 seconds / sheet or less, printing wrinkles and sticking occur under the conditions for the time required for printing. It is preferable that sufficient lubricity is imparted to the back layer so that there is no such problem. Examples of a method for imparting sufficient lubricity to the back layer include a method of containing a lubricant component in the back layer. The lubricant component is as described for the back layer of the thermal transfer sheet of the present invention.

(Thermal transfer image receiving sheet)
Next, the thermal transfer image receiving sheet used in the image forming method of the present invention will be described. As shown in FIG. 3, the thermal transfer image receiving sheet 30 used in the present invention has a configuration in which a dye receiving layer 22 is provided on one surface of another substrate 21. The other substrate 21 and the dye receiving layer 22 are not limited in any way, and a conventionally known configuration can be used as it is.

  For example, the dye receiving layer 22 is a water-based dye receiving layer 22, specifically, a resin that can be dissolved or dispersed in an aqueous solvent, such as a water-soluble resin, a water-soluble polymer, or an aqueous resin, is dissolved in the aqueous solvent. Alternatively, in the case of a dye receiving layer formed using a dispersed aqueous coating liquid, a polyester resin, an acrylic resin, an acrylic-urethane resin, a vinyl chloride resin, or a (meth) acrylic Non-illustrated sealing layer containing components such as acid alkyl ester homopolymer emulsion, (meth) acrylic acid alkyl ester-styrene copolymer emulsion, (meth) acrylic acid alkyl ester-vinyl acetate copolymer emulsion, cement filler emulsion Is preferably provided. Further, a heat insulating layer (not shown) including hollow particles having a function of imparting heat insulating properties and cushioning properties may be provided between the other base material 21 and the dye receiving layer 22.

(Image formation)
In the image forming method of the present invention, the time required for printing the thermal transfer sheet at the time of image formation is defined as 10 seconds / sheet or less. According to the image forming method of the present invention in which the time required for printing the thermal transfer sheet during image formation is 10 seconds / sheet or less, it is possible to form an image at high speed. Further, the speed at the time of image formation is the same as the speed at which the used thermal transfer sheet used for image formation is wound, but as described above, the thermal transfer sheet used in the image forming method of the present invention. Since the detection mark provided on the base material contains alumina particles or calcium carbonate particles, the used thermal transfer sheet is wound up even when image formation is performed at high speed. In this case, it is possible to prevent the winding slip from occurring. Although there is no particular limitation on the lower limit of the required printing time, printing wrinkles and sticking are liable to occur under conditions of less than 3 seconds / sheet, and it is preferably 3 seconds / sheet or more.

  Hereinafter, the present invention will be described with reference to examples and comparative examples. “Part” in the text is based on mass unless otherwise specified. Moreover, a particle diameter is a primary average particle diameter.

Example 1
As a base material, a long, easy-adhesion-treated polyethylene terephthalate film having a width of 160 mm, a length: 225 m, and a thickness: 5 μm was prepared, and a back layer coating liquid 1 having the following composition was formed on one entire surface of the base material. Was applied at a dryness of 0.8 g / m ² to form a back layer. Next, an undercoat layer coating liquid is applied to the entire other surface of the base material so that the dry coating amount is 0.1 g / m ² and dried to form an undercoat layer. Thus, a laminate in which the back layer / base material / undercoat layer was laminated in this order was obtained. A yellow dye layer coating liquid 1, a magenta dye layer coating liquid 1, and a cyan dye layer coating liquid 1 are respectively formed on the undercoat layer of the laminate so that one screen has the form shown in FIG. The Y dye layer, the M dye layer, and the C dye layer were formed by coating so that the coating amount during drying was 0.6 g / m ² . Further, using the release layer coating solution 1, the transferable protective layer coating solution 1, and the detection mark coating solution 1 so that the form shown in FIG. A release layer, a transferable protective layer, and a detection mark were formed so as to be m ² , 1.0 g / m ² , and 0.6 g / m ² . The thermal transfer sheet of Example 1 was produced by repeatedly forming 400 screens on the laminate and processing it into the same form as a genuine ribbon for DS40 printer.

<Back layer coating liquid 1>
・ Polyvinyl butyral resin 40 parts (SREC BX-1 manufactured by Sekisui Chemical Co., Ltd.)
・ Polyisocyanate (solid content 100% NCO = 17.3 mass%) 35 parts (Bernock D750-45 manufactured by Dainippon Ink & Chemicals, Inc.)
-Zinc stearyl phosphate 10 parts (LBT-1830 refining Sakai Chemical Industry Co., Ltd.)
・ 10 parts of zinc stearate (SZ-PF manufactured by Sakai Chemical Industry Co., Ltd.)
・ 5 parts of talc (Microace P-3 manufactured by Nippon Talc Industry Co., Ltd.)
・ Methyl ethyl ketone 450 parts ・ Toluene 450 parts

<Coating liquid 1 for undercoat layer>
Colloidal silica (particle diameter 4-6 nm, solid content 10%) 30 parts (Snowtex OXS, manufactured by Nissan Chemical Industries, Ltd.)
・ Polyvinylpyrrolidone resin (K-90, manufactured by ISP) 3 parts ・ Water 50 parts ・ Isopropyl alcohol 17 parts

<Yellow dye layer coating solution 1>
・ Solvent Yellow 93 2.0 parts ・ Disperse Yellow 231 2.0 parts ・ Polyvinyl acetal resin 3.5 parts (ESREC KS-5 Sekisui Chemical Co., Ltd.)
・ Polyethylene wax 0.1 part ・ Methyl ethyl ketone 45.0 parts ・ Toluene 45.0 parts

<Coating liquid 1 for magenta dye layer>
・ Disperse dye (MS Red G) 1.5 parts ・ Disperse dye (Macrolex Red Violet R) 2.0 parts ・ Polyvinyl acetal resin 4.5 parts (ESREC KS-5, manufactured by Sekisui Chemical Co., Ltd.)
・ Polyethylene wax 0.1 part ・ Methyl ethyl ketone 45.0 parts ・ Toluene 45.0 parts

<Cyan dye layer coating solution 1>
・ Solvent Blue 63 2.0 parts ・ Disperse Blue 354 2.0 parts ・ Polyvinyl acetal resin 3.5 parts (ESREC KS-5 Sekisui Chemical Co., Ltd.)
・ Polyethylene wax 0.1 part ・ Methyl ethyl ketone 45.0 parts ・ Toluene 45.0 parts

<Release layer coating solution 1>
・ Silicone-modified acrylic resin (solid content 50%) 16 parts (Cell Top 226, manufactured by Daicel Chemical Industries, Ltd.)
Aluminum catalyst (solid content 10%) 3 parts (Cell Top CAT-A manufactured by Daicel Chemical Industries, Ltd.)
・ Methyl ethyl ketone 8 parts ・ Toluene 8 parts

<Coating liquid 1 for transferable protective layer>
・ Acrylic resin 20 parts (Dianar BR87, manufactured by Mitsubishi Rayon Co., Ltd.)
・ Methyl ethyl ketone 40 parts ・ Toluene 40 parts

<Detection mark coating solution 1>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
・ Amorphous alumina particles 1.4 parts (SA32 Nippon Light Metal Co., Ltd. particle size: 1 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Example 2)
A thermal transfer sheet of Example 2 was prepared in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to a detection mark coating solution 2 having the following composition.

<Detection mark coating solution 2>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-14 parts of amorphous alumina particles (SA32 Nippon Light Metal Co., Ltd. particle diameter: 1 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

Example 3
A thermal transfer sheet of Example 3 was produced in the same manner as Example 1 except that the detection mark coating solution 1 was changed to the detection mark coating solution 3 having the following composition.

<Detection mark coating solution 3>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
・ 28 parts of amorphous alumina particles (SA32 Nippon Light Metal Co., Ltd., particle size: 1 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

Example 4
A thermal transfer sheet of Example 4 was prepared in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to a detection mark coating solution 4 having the following composition.

<Detection mark coating solution 4>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-14 parts of amorphous alumina particles (SA34 manufactured by Nippon Light Metal Co., Ltd. Particle size: 4 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Example 5)
A thermal transfer sheet of Example 5 was produced in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to a detection mark coating solution 5 having the following composition.

<Detection mark coating solution 5>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-14 parts of spherical alumina particles (AX3-15 manufactured by Nippon Steel Materials Co., Ltd., Micron Corporation, particle size: 2.5 μm to 4.5 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Example 6)
A thermal transfer sheet of Example 6 was produced in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to a detection mark coating solution 6 having the following composition.

<Detection mark coating solution 6>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
・ Amorphous calcium carbonate particles 1.4 parts (White seal WS-K Takehara Chemical Industry Co., Ltd. particle diameter: 5 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Example 7)
A thermal transfer sheet of Example 7 was produced in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to the detection mark coating solution 7 having the following composition.

<Detection mark coating solution 7>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
・ 14 parts of amorphous calcium carbonate particles (White Seal WS-K, Takehara Chemical Industry Co., Ltd., particle size: 5 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Example 8)
A thermal transfer sheet of Example 8 was prepared in the same manner as in Example 1 except that the detection mark coating liquid 1 was changed to a detection mark coating liquid 8 having the following composition.

<Detection mark coating solution 8>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
・ Amorphous calcium carbonate particles 28 parts (White seal WS-K Takehara Chemical Industry Co., Ltd. particle size: 5 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

Example 9
A thermal transfer sheet of Example 9 was prepared in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to a detection mark coating solution 9 having the following composition.

<Detection mark coating solution 9>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-Amorphous calcium carbonate particles 14 parts (ACE-35 Hayashi Kasei Co., Ltd. particle diameter: 0.7 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Example 10)
A thermal transfer sheet of Example 10 was produced in the same manner as in Example 1 except that the detection mark coating liquid 1 was changed to a detection mark coating liquid 10 having the following composition.

<Detection mark coating solution 10>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-14 parts of amorphous calcium carbonate particles (Neolite SP-100, Takehara Chemical Industries, Ltd., particle size: 0.08 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Example 11)
A thermal transfer sheet of Example 11 was prepared in the same manner as in Example 1 except that the detection mark coating liquid 1 was changed to the detection mark coating liquid 11 having the following composition.

<Detection mark coating solution 11>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-Amorphous alumina particles 56 parts (SA32 Nippon Light Metal Co., Ltd. particle diameter: 1 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Example 12)
Example 1 except that the back layer coating solution 1 was changed to a back layer coating solution 2 having the following composition, and the detection mark coating solution 1 was changed to the detection mark coating solution 2 having the above composition. In the same manner, a thermal transfer sheet of Example 12 was produced.

<Back layer coating liquid 2>
・ 35 parts of polyvinyl acetal resin (S-REC KS-1 manufactured by Sekisui Chemical Co., Ltd.)
・ Polyisocyanate (solid content 45%) 30 parts (Bernock D750-45, manufactured by Dainippon Ink & Chemicals, Inc.)
-Zinc stearyl phosphate 10 parts (LBT-1830 refining Sakai Chemical Industry Co., Ltd.)
・ 10 parts of zinc stearate (SZ-PF manufactured by Sakai Chemical Industry Co., Ltd.)
・ Phosphate 10 parts (Pricesurf A-208N, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
・ 5 parts of talc (Microace P-3 manufactured by Nippon Talc Industry Co., Ltd.)
・ Methyl ethyl ketone 450 parts ・ Toluene 450 parts

(Example 13)
Example 1 except that the back layer coating solution 1 was changed to the back layer coating solution 2 having the above composition and the detection mark coating solution 1 was changed to the detection mark coating solution 7 having the above composition. In the same manner, a thermal transfer sheet of Example 13 was produced.

(Comparative Example 1)
A thermal transfer sheet of Comparative Example 1 was produced in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to the detection mark coating solution A having the following composition.

<Detection mark coating liquid A>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Comparative Example 2)
A thermal transfer sheet of Comparative Example 2 was produced in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to the detection mark coating solution B having the following composition.

<Detection mark coating solution B>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-14 parts of amorphous titanium oxide particles (TTO-D2 manufactured by Ishihara Sangyo Co., Ltd., particle size: 0.25 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Comparative Example 3)
A thermal transfer sheet of Comparative Example 3 was prepared in the same manner as in Example 1 except that the detection mark coating liquid 1 was changed to a detection mark coating liquid C having the following composition.

<Detection mark coating solution C>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-14 parts of amorphous silica particles (Silicia 310P, manufactured by Fuji Silysia Chemical Ltd., particle size: 2.7 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Comparative Example 4)
A thermal transfer sheet of Comparative Example 4 was prepared in the same manner as in Example 1 except that the detection mark coating solution 1 was changed to the detection mark coating solution D having the following composition.

<Detection mark coating solution D>
・ Carbon black 60 parts ・ Vinyl chloride-vinyl acetate copolymer 100 parts (# 1000GK manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ 100 parts of urethane resin (HMS-20 manufactured by Nippon Polyurethane Co., Ltd.)
-14 parts of irregular talc particles (Microace P-3 manufactured by Nippon Talc Co., Ltd., particle size: 5 μm)
・ 160 parts of methyl ethyl ketone ・ 160 parts of toluene

(Winding evaluation)
The thermal transfer sheets of each Example and Comparative Example obtained above were set in a sublimation type transfer printer (DS-40 manufactured by DNP Photolcio Co., Ltd.), 400 screen continuous printing was performed on DS-40 genuine image receiving paper, The winding deviation of the winding side ribbon was confirmed. Further, DS-40 used here was prepared by preparing a printer in which the winding tension was set to the usual 80% and a printer set to 60%, and evaluated with each printer. The required printing time for DS-40 is 8 seconds / sheet.

(Evaluation criteria)
◎: No winding misalignment ○: Slightly deviated but without image obstruction and easily removable ×: Winding misalignment occurs and difficult to remove

DESCRIPTION OF SYMBOLS 10,100 ... Thermal transfer sheet 1 ... Base material 3 ... Dye layer 4 ... Detection mark 5 ... Back layer 30 ... Thermal transfer image receiving sheet 21 ... Other base material 22 ... Dye receiving layer 101 ... Supply roller 102 ... Winding roller

Claims (5)

A thermal transfer sheet provided with a dye layer on one side of the substrate and a back layer on the other side of the substrate,
On one side of the substrate or on the dye layer, when the thermal transfer sheet is wound up, a detection mark is provided at a position in contact with the back layer,
The detection mark contains alumina particles or calcium carbonate particles as inorganic particles ,
The back layer contains, as a lubricant component, either one or both of zinc stearate and zinc stearyl phosphate,
The thermal transfer sheet , wherein a content of the lubricant component is within a range of 10% by mass or more and 50% by mass or less with respect to a total solid mass of the back layer .   The thermal transfer sheet according to claim 1, wherein the inorganic particles are inorganic particles having a shape having one or more corners.   The thermal transfer sheet according to claim 1 or 2, wherein the inorganic particles are contained at a ratio of 0.5% by mass or more with respect to the total solid content of the detection mark.   4. The thermal transfer sheet according to claim 1, wherein the inorganic particles have a primary average particle size in a range of 0.1 μm to 15 μm. A dye transfer layer provided on one side of the substrate, a thermal transfer sheet provided with a back layer on the other side of the substrate, and a dye receiving layer provided on one side of the other substrate An image forming method for forming an image on a thermal transfer image receiving sheet by using in combination with a thermal transfer image receiving sheet,
On one side of the substrate or on the dye layer, when the thermal transfer sheet is wound up, a detection mark is provided at a position in contact with the back layer,
The detection mark contains alumina particles or calcium carbonate particles as inorganic particles,
The back layer contains, as a lubricant component, either one or both of zinc stearate and zinc stearyl phosphate,
The image forming method , wherein a content of the lubricant component is within a range of 10% by mass or more and 50% by mass or less with respect to a total mass of the solid content of the back layer .

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