JP2014198418A - Method for manufacturing thermal transfer image receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a thermal transfer image receiving sheet which is capable of suppressing printing unevenness when an image is formed using an image forming apparatus including a paper feed roller for transporting the thermal transfer image receiving sheet.SOLUTION: A method for manufacturing a thermal transfer image receiving sheet 10 comprises: preparing a thermal transfer image receiving sheet having a substrate 11, and hollow layers 12 and 13 and a receiving layer 15, which are disposed on the substrate 11 in the order named; and calendering the thermal transfer image receiving sheet while holding it between two support rollers disposed at intervals of 50-99% of the thickness of the thermal transfer image receiving sheet.

Description

  The present invention relates to a method for producing a thermal transfer image receiving sheet, and more specifically, a base material, and a thermal transfer image receiving sheet having a hollow layer and a receiving layer in this order on the base material are arranged at specific intervals. The present invention relates to a method for manufacturing a thermal transfer image-receiving sheet, which includes a step of carrying out a calendar process by being sandwiched between two supported rollers.

  Conventionally, various printing methods are known. Among them, the thermal diffusion type transfer method (sublimation type thermal transfer method) uses a sublimation dye as a color material, so that density gradation can be freely adjusted, and intermediate colors and gradations can be adjusted. It has excellent tone reproducibility and can form high-quality images comparable to silver halide photographs.

  This thermal diffusion transfer system is a method in which a thermal transfer ink sheet containing a dye (sublimation dye) and a thermal transfer image receiving sheet are superposed, and then the ink sheet is heated by a thermal head whose heat generation is controlled by an electrical signal. The dye in the ink sheet is transferred to the image receiving sheet to record image information. As such thermal diffusion transfer systems become widespread, the printing speed has been increased, and sufficient color density can be obtained even if the conventional thermal energy is printed using the conventional thermal transfer ink sheet and thermal transfer image receiving sheet. There are problems such as inability to obtain.

  Furthermore, there are various other problems in the thermal diffusion transfer system. For example, due to insufficient releasability of the image receiving sheet, the ink sheet sticks to the receiving layer surface of the image receiving sheet at the time of printing, and when the ink sheet is peeled off from the image receiving layer after printing, generation of peeling sound, Problems such as poor running and occurrence of peeling lines on the image have occurred.

  Another problem is that it is difficult to obtain a uniform image due to the unevenness of the surface of the thermal transfer image receiving sheet. Therefore, it has been proposed to perform a calendar process in order to reduce and smooth the unevenness on the surface of the thermal transfer image receiving sheet (see, for example, Patent Document 1).

JP 2008-6758 A

  As a result of studying the above-described background art, the inventors of the present invention, in particular, in an image forming apparatus including a paper feed roller that conveys a thermal transfer image receiving sheet, the thermal transfer image receiving image is brought into contact with the pinch roller when the thermal transfer image receiving sheet is conveyed. It was found that a part of the sheet was rubbed, and the image formed in the rubbed portion was uneven in printing.

  The present invention has been made in view of the above-described background art and newly discovered problems, and the object thereof is a case where an image is formed using an image forming apparatus including a paper feed roller for conveying a thermal transfer image receiving sheet. However, an object of the present invention is to provide a method for manufacturing a thermal transfer image receiving sheet that can suppress uneven printing.

  As a result of intensive studies, the inventors of the present invention have carried out a calendering process by sandwiching a thermal transfer image-receiving sheet having a specific layer configuration by two support rollers arranged at a specific interval, whereby a hollow layer of the thermal transfer image-receiving sheet It has been found that the above-mentioned problems can be solved by modifying the surface state of the receiving layer without crushing. The present invention has been completed based on such findings.

That is, according to one aspect of the present invention,
A step of preparing a thermal transfer image receiving sheet comprising a base material, and a hollow layer and a receiving layer in this order on the base material;
Sandwiching the thermal transfer image receiving sheet by two support rollers arranged at an interval of 50% to 99% of the thickness of the thermal transfer image receiving sheet, and performing a calendar process;
A method for producing a thermal transfer image-receiving sheet is provided.

  In the aspect of the present invention, the distance between the two support rollers is preferably 60% to 95% of the thickness of the thermal transfer image receiving sheet.

  In the aspect of the present invention, it is preferable that the surface temperature of at least one of the two support rollers is 150 ° C. to 250 ° C.

  In the aspect of this invention, it is preferable that the said receiving layer contains binder resin and a mold release agent.

  In the aspect of the present invention, it is preferable that the binder resin includes at least one selected from the group consisting of a vinyl chloride resin, a polyester resin, and an acrylic resin.

  In the embodiment of the present invention, it is preferable that the release agent comprises a silicone dispersion.

  In the aspect of the present invention, it is preferable that the receiving layer further comprises a wax additive and / or a urethane-associative thickener.

  In the aspect of the present invention, the hollow layer preferably comprises hollow particles.

  In the aspect of the present invention, it is preferable that all the layers constituting the surface side having the receiving layer on the base material are formed by aqueous coating.

According to another aspect of the invention,
Two supports in which a base material, and a thermal transfer image receiving sheet having a hollow layer and a receiving layer in this order on the base material are arranged at an interval of 50% to 99% of the thickness of the thermal transfer image receiving sheet There is provided a calendering method for a thermal transfer image receiving sheet, characterized in that the calendering process is performed by being sandwiched between rollers.

  In another aspect of the present invention, the distance between the two support rollers is preferably 60% to 95% of the thickness of the thermal transfer image receiving sheet.

  In another aspect of the present invention, the surface temperature of at least one of the two support rollers is preferably 150 ° C to 250 ° C.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the thermal transfer image receiving sheet which can suppress the printing nonuniformity at the time of image formation can be provided.

1 is a schematic cross-sectional view showing an embodiment of a thermal transfer image receiving sheet according to the present invention. It is a perspective view of the calendar processing method of the thermal transfer image receiving sheet by this invention. It is a schematic cross section of the calendar processing method of the thermal transfer image receiving sheet according to the present invention. 2 is an SEM image of the surface of a thermal transfer image receiving sheet produced in Example 1. 3 is an SEM image of the surface of a thermal transfer image receiving sheet produced in Comparative Example 1.

Thermal transfer image-receiving sheet The thermal transfer image-receiving sheet of the present invention comprises a base material, a hollow layer, and a receiving layer on the base material in this order, and is subjected to the following calendar treatment. In a preferred embodiment, the thermal transfer image-receiving sheet may further have a primer layer between the hollow layer and the receiving layer, and may further have a back layer on the surface opposite to the receiving layer. Hereinafter, the structure of the thermal transfer image receiving sheet of the present invention will be described with reference to the drawings.

  According to one aspect of the present invention, there is provided a thermal transfer image receiving sheet comprising, on a base material, two hollow layers, a primer layer, and a receiving layer in this order. Specifically, a schematic cross-sectional view of one embodiment of the thermal transfer image receiving sheet according to the present invention is shown in FIG. A thermal transfer image receiving sheet 10 shown in FIG. 1 includes a base material 11, a hollow layer A (lower layer) 12, a hollow layer B (upper layer) 13, a primer layer 14, and a receiving layer 15 on the base material 11. In this order.

Base material The base material in the present invention has a role of holding the hollow layer and the receiving layer, and heat is applied at the time of thermal transfer, so that it has mechanical strength that does not hinder handling even in a heated state. A material is preferred.

  Examples of the base material include condenser paper, glassine paper, sulfuric acid paper, high-size paper, synthetic paper (polyolefin-based, polystyrene-based), high-quality paper, art paper, coated paper, and resin-coated paper. , Cast coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, or polyester, polyacrylate, polycarbonate, polyurethane, polyimide, polyether Imide, cellulose derivative, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, Examples include polyethersulfone, tetrafluoroethylene, perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene / ethylene, tetrafluoroethylene / hexafluoropropylene, polychlorotrifluoroethylene, and polyvinylidene fluoride. A white opaque film formed by adding a white pigment or a filler to these synthetic resins can also be used, and is not particularly limited. Moreover, the laminated body by the arbitrary combinations of the said base material can also be used. Examples of typical laminates include cellulose fiber paper and synthetic paper, or synthetic paper of cellulose synthetic paper and a plastic film. In this invention, a commercially available base material can also be used, for example, RC paper (Mitsubishi Paper Co., Ltd. make, brand name) etc. are preferable. The base material thickness can be appropriately changed according to the strength and heat resistance required for the thermal transfer image-receiving sheet and the material of the material employed as the base material. Specifically, the base material thickness is 50 μm. It is preferable to be within a range of ˜1000 μm, and it is more preferable to be within a range of 100 μm to 300 μm.

Receiving layer The receiving layer in the present invention receives the sublimation dye transferred from the thermal transfer ink sheet during image formation by thermal transfer, and holds the received sublimation dye in the receiving layer, whereby an image is formed on the surface of the receiving layer. Can be formed and maintained. The receiving layer preferably contains a binder resin and a release agent, and may further contain a wax additive or a urethane-associative thickener.

  Binder resins contained in the receiving layer include acrylic resins, vinyl chloride resins, polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride, vinyl chloride / vinyl acetate copolymers (vinyl acetate resin), poly Halogenated polymers such as vinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylates, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, olefins such as ethylene and propylene, and other Examples thereof include copolymer resins with vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, and polycarbonates. In particular, it is preferable to use at least one selected from the group consisting of a vinyl chloride resin, a polyester resin, and an acrylic resin.

  Examples of the release agent contained in the receiving layer include silicone dispersions (including reactive curable silicones), phosphate ester plasticizers, and fluorine compounds, and silicone dispersions are particularly preferable. Various modified silicones such as dimethyl silicone can be used as the silicone dispersion. Specifically, amino-modified silicone, epoxy-modified silicone, alcohol-modified silicone, vinyl-modified silicone, urethane-modified silicone, polyester-modified silicone, polyether-modified silicone, polyester-modified silicone dispersion, acrylic-modified silicone, amide-modified silicone, etc. are used. These can also be mixed or polymerized using various reactions. Two or more release agents may be mixed and used. By using such a release agent, problems such as fusion between the thermal transfer ink sheet and the receiving layer of the thermal transfer image receiving sheet and a decrease in printing sensitivity during printing can be improved. Further, in the step of performing the calendar process, the support roller (heating roller) and the receiving layer can be more smoothly separated. In the present invention, it is particularly preferable to use a polyether-modified silicone type release agent. Two or more polyether-modified silicone mold release agents may be used, or other mold release agents may be used in combination. In the present invention, a commercially available release agent may be used, and examples thereof include X22-3000T and KF410 (manufactured by Shin-Etsu Chemical Co., Ltd.). Use of such an epoxy-modified silicone is preferable from the viewpoint of combination with the binder resin.

  Examples of the wax additive contained in the receiving layer include carnauba wax and paraffin wax, and these may be used alone or in combination. In the present invention, the carnauba wax includes natural carnauba wax and purified products and derivatives thereof, including those modified with additives and the like. According to a preferred embodiment, the melting point of carnauba wax is 80 to 90 ° C., the acid value is 10 mg · KOH / g or less, and the saponification value is 78 to 88 mg · KOH / g. The paraffin wax includes natural paraffin wax and purified products and derivatives thereof, and those modified with additives and the like. The melting point of the paraffin wax is preferably 40 to 105 ° C, more preferably 40 to 90 ° C, and further preferably 40 to 75 ° C.

  The content of the wax additive is preferably 5% by mass or more and more preferably 5% by mass or more and 15% by mass or less with respect to the solid content mass of the binder resin of the receiving layer. If the content of the wax additive is within the above range, the support roller (heating roller) and the receiving layer can be more smoothly peeled off in the calendaring step.

The urethane associative thickener contained in the receiving layer has a viscosity when measured at a liquid temperature of 25 ° C. according to JIS Z8803 using a B-type viscometer when the solid concentration is 30%. , Preferably it is 1000-100000 mPa * s, More preferably, it is 2000-60000 mPa * s. Furthermore, the viscosity ratio is the following formula (1):
Viscosity ratio = V _30,6 / V _30,60 (1)
_{(Wherein, V 30,6} by using a B-type viscometer, in conformity with JIS Z8803, a viscosity (mPa.s) when the rotational speed 6rpm at a liquid temperature 25 ° _{C., V 30, 60} is B Using a viscometer, the viscosity (mPa.s) at a liquid temperature of 25 ° C. and a rotational speed of 60 rpm is shown in accordance with JIS Z8803)
And is preferably 2.0 to 5.0, more preferably 2.0 to 4.5. This viscosity ratio is generally called a thixotropy index (TI) and is an index that correlates with sagging difficulty. By using a urethane associative thickener with a viscosity and a viscosity ratio in the above range, it gives leveling viscosity to the coating solution for the receiving layer, improves surface quality, and exists in the form of particles. Binders are bound together to form a film, and heat fusion during image printing can be suppressed.

  The content of the urethane associative thickener is preferably 5 to 20% by mass, more preferably 6 to 15% by mass, based on the solid content of the binder resin in the receptor layer. When the content of the urethane associative thickener is within the above range, the receptor layer can be sufficiently formed, and heat fusion during image printing can be suppressed. In the present invention, a commercially available urethane associative thickener can also be used. For example, UH-450, UH-526, UH-530, UH-540, UH-550 (above, manufactured by ADEKA Corporation), SN thickener A812 (manufactured by San Nopco) is preferable.

Hollow layer The hollow layer in the present invention has a heat insulating property that can prevent heat applied during image formation by thermal transfer from being lost due to heat transfer to a substrate or the like. In a preferred embodiment, the hollow layer contains hollow particles and may further contain a hydrophilic binder and other additives. According to a preferred embodiment, the hollow layer may be composed of two or more layers. A hollow layer is provided with cushioning properties by including hollow particles. Here, the degree of cushioning property of the hollow layer can be appropriately adjusted according to the application of the thermal transfer image receiving sheet. The degree of cushioning property of the hollow layer can also be adjusted to an arbitrary range by changing the thickness of the hollow layer, for example. The thickness of the hollow layer is not particularly limited as long as the heat insulating property, cushioning property and the like can be adjusted to a desired level, but preferably in the range of 10 μm to 100 μm, and in the range of 10 μm to 50 μm. More preferably, it is within. The density of the hollow layer, for example in the range of ^{0.1g / cm 3 ~0.8g / cm 3} , preferably in the range of inter alia ^{0.2g / cm 3 ~0.7g / cm 3} .

  The average particle diameter of the hollow particles used in the present invention is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm. If the average particle diameter of the hollow particles is in the above range, heat insulation and cushioning properties can be imparted to the hollow layer. In the present invention, the volume average particle diameter of the hollow particles can be measured by a conventionally known method such as the Coulter method (Sysmex FPIA-3000 by Malvern). The average hollowness of the hollow particles is preferably 20% or more, more preferably 30 to 80%. If the average hollowness of the hollow particles is in the above range, heat insulation and cushioning properties can be imparted to the hollow layer. Furthermore, the organic hollow particle comprised from resin etc. may be sufficient, and the inorganic hollow particle comprised from glass etc. may be sufficient. The hollow particles may be cross-linked hollow particles. In the present invention, commercially available hollow particles can also be used. For example, Ropeke HP-1055, Ropeke HP-91, Ropeke OP-84J, Ropeke Ultra, Ropeke SE, and Ropeke ST (Rohm and Haas Co., Ltd.) ), Nipol MH-5055 (Nippon Zeon Corporation), SX8782 and SX866 (JSR Corporation) are preferred.

Other Layers The thermal transfer image receiving sheet of the present invention may further have other layers other than the above layers. In a preferred embodiment, the thermal transfer image-receiving sheet can further have other layers such as a primer layer, an intermediate layer, and a release layer on the receiving layer side. Moreover, it can have a back surface layer on the opposite side to a receiving layer.

Primer layer The primer layer in the present invention has a role of satisfactorily adhering the hollow layer and the receiving layer, and prevents image migration to the hollow layer side in a high-temperature and high-humidity environment, thereby improving image storage stability. It has a function. In a preferred embodiment, the primer layer contains hollow particles, a resin, and a hydrophilic binder, and the resin preferably contains an acrylic resin. Although it does not specifically limit as thickness of a primer layer, For example, it is preferable that they are 1 micrometer-40 micrometers, 1 micrometer-20 micrometers are more preferable, and 1 micrometer-10 micrometers are more preferable.

  In the present invention, the acrylic resin refers to a polymer of acrylic acid or methacrylic acid monomer or derivative thereof, a polymer of acrylic acid ester or methacrylic acid ester monomer or derivative thereof, acrylic acid or methacrylic acid monomer and other derivatives. It includes a copolymer with a monomer or a derivative thereof, and a copolymer of a monomer of an acrylate ester or a methacrylate ester with another monomer or a derivative thereof.

  According to a preferred embodiment of the present invention, the acrylic resin is preferably a copolymer of an acrylic ester or methacrylic ester monomer and another monomer or a derivative thereof. Examples of the acrylic acid ester or methacrylic acid ester monomer include alkyl acrylate and alkyl methacrylate, preferably methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, lauryl acrylate, and lauryl methacrylate. Can be mentioned. Examples of other monomers include aromatic hydrocarbons, aryl group-containing compounds, amide group-containing compounds, and vinyl chloride, preferably styrene, benzylstyrene, phenoxyethyl methacrylate, acrylamide, and methacrylamide. it can. In the present invention, a copolymer of an alkyl acrylate or an alkyl methacrylate and at least one other monomer selected from the group consisting of an aromatic hydrocarbon, an aryl group-containing compound, and an amide group-containing compound, or a derivative thereof. It is particularly preferable to use it. By copolymerizing the monomers as described above, the concentration and releasability can be improved. Two or more acrylic resins may be mixed and used.

  According to a preferred embodiment of the present invention, the hydrophilic binder contained in the hollow layer or primer layer described above includes gelatin and derivatives thereof, polyvinyl alcohol, polyethylene oxyside, polyvinyl pyrrolidone, pullulan, carboxymethyl cellulose, hydroxyethyl cellulose, Examples include dextran, dextrin, polyacrylic acid and salts thereof, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan, casein, xanthene gum, locust bean gum, alginic acid, and gum arabic, with gelatin being particularly preferred. By using such a hydrophilic binder, interlayer adhesion of each layer can be improved. In particular, when each layer is formed by an aqueous coating method and a simultaneous multilayer coating method, by using gelatin, the viscosity of each coating solution can be adjusted to a desired range, and a desired film thickness can be obtained. In the present invention, commercially available gelatin can also be used. For example, RR, R, CLV, and N1236 (manufactured by Nitta Gelatin Co., Ltd.) are preferable.

Intermediate Layer In the present invention, at least one intermediate layer may be provided between the hollow layer and the primer layer or between the primer layer and the receiving layer. By providing an intermediate layer, functions such as solvent resistance, dye diffusion barrier during image storage under high temperature / high humidity, interlayer adhesion, white color imparting, glare / unevenness of the substrate, and antistatic functions are added. Can do. As a method for forming the intermediate layer, known means can be used. For example, an optical brightener, inorganic fine particles, hollow fine particles, and an organic conductive material such as a conductive filler or polyaniline sulfonic acid are added to the intermediate layer. The method of doing is mentioned.

Release layer In the present invention, the release agent may not be added to the receiving layer, but may be provided as a separate release layer on the receiving layer.

Back layer The back layer in the present invention has the fixability of ink used in an ink jet method, a dot impact method, a writing instrument, and the like, and enables a back print excellent in quick-drying with less bleeding of the recording portion ( To improve the backprint suitability). Furthermore, it also has the basic characteristics as the image receiving paper back side described below.
1. When superposed on the receiving layer surface, no sticking (blocking) occurs even if it is stored under a temperature or load.
2. Even when the paper is mistakenly mounted on the printer with the front and back sides reversed, and the thermal transfer sheet is superposed on the thermal transfer sheet, it will stick to the thermal transfer sheet and will not clog in the printer, and the printed matter will be discharged. (Has back surface releasability).
3. Even if it rubs against the receiving layer surface, the receiving layer surface is not damaged, and the particle component does not fall off (powder off) from the back layer.
The back layer preferably contains a binder resin and inorganic fine particles, and other additives such as an antifoaming agent and an antistatic agent can be appropriately added to the back layer. In recent years, a water-based coating method is preferred from the viewpoint of environmental considerations, but the back layer of the present invention can be particularly suitably used as the back surface of an image receiving paper on which a receiving layer is formed by a water-based coating method.

  The binder resin contained in the back layer is at least one selected from the group consisting of styrene / acrylic resins, polyester resins, polyurethane resins, and acrylic resins. By using such a binder resin, it is possible to have good adhesion to the base material and good backprint suitability. In the present invention, a commercially available binder resin can also be used, such as Bironal MD 1500 (manufactured by Toyobo Co., Ltd.), Plus Coat Z690 (manufactured by Kyoyo Chemical Co., Ltd.), Superflex 130 (Daiichi Kogyo Seiyaku ( Etc.) are preferable.

  The inorganic fine particles contained in the back layer are at least one selected from the group consisting of colloidal alumina, colloidal silica, and silica particles. By using such inorganic fine particles, it is possible to improve the backprint suitability and prevent blocking.

In the present invention, but are not coating amount of the back layer is particularly limited, it is preferable that the coating amount is in the range of drying after ^{0.1g / m 2 ~3.0g / m 2} , 0.3g / More preferably, it is in the range of m ^{2 to} 1.5 g / m ² . If the coating amount is in the above range, sufficient back print suitability can be obtained.

Calendar Processing The thermal transfer image-receiving sheet of the present invention is subjected to calendar processing by being sandwiched between two support rollers arranged at specific intervals, for example, an elastic roller and a metal roller. As shown in FIG. 2, the thermal transfer image receiving sheet 20 is conveyed in the direction of the arrow while being sandwiched between two support rollers 21 and 22. As shown in FIG. 3, the distance 23 between the two support rollers is narrower than the thickness 24 of the thermal transfer image receiving sheet, and is 50% to 99%, preferably 60% to 95% of the thickness 24 of the thermal transfer image receiving sheet. It is preferably 65% to 90%, more preferably 70% to 85%. The distance between the two support rollers can be adjusted using a conventionally known method, for example, a jig called a cotter. By adjusting the distance between the two support rollers to the above range and performing the calendering process, the surface state of the receiving layer is modified without crushing the hollow layer of the thermal transfer image-receiving sheet, and uneven printing or separation during image formation is achieved. The type property can be suppressed. In addition, the handling of printed matter can be improved. The judgment property is the degree of ease of judgment when a plurality of prints are stacked.

  The surface temperature of at least one of the two support rollers used for the calendering process is preferably 150 ° C to 300 ° C, more preferably 160 ° C to 250 ° C, and still more preferably 190 ° C to 230 ° C. The surface temperature of the support roller is preferably equal to or higher than the melting point of the binder resin of the receiving layer. If the surface temperature of at least one support roller is in the above range, the resin contained in the receiving layer is sufficiently melted, or the additive contained in the receiving layer is sufficiently bleed on the surface of the receiving layer. This is because the state can be modified. Thereby, it is possible to further suppress printing unevenness during image formation.

  The linear pressure during the calendar treatment is preferably 1 to 80 kg / cm, more preferably 10 to 75 kg / cm, and still more preferably 20 to 70 kg / cm. By adjusting the linear pressure to the above range and applying the calendar process, the surface state of the receiving layer is modified without crushing the base material and each layer (especially the hollow layer) constituting the thermal transfer image-receiving sheet. Printing unevenness can be further suppressed.

  The line speed (processing speed per minute) when performing the calendar process is preferably 30 to 250 m / min, more preferably 50 to 250 m / min, and still more preferably 100 to 250 m / min. By adjusting the line speed to the above range and carrying out the calendering process, the surface state of the receiving layer can be modified without crushing the hollow layer of the thermal transfer image-receiving sheet, thereby further suppressing uneven printing during image formation. it can.

  The number of combinations (number of nips) of the calender device and the two support rollers used for the calendering process is not particularly limited, and known ones can be used.

Method for Producing Thermal Transfer Image-Receiving Sheet A method for producing a thermal transfer image-receiving sheet of the present invention comprises a step of preparing a thermal transfer image-receiving sheet comprising a substrate, a hollow layer, and a receptor layer in this order on the substrate, and thermal transfer A step of holding the image receiving sheet between two supporting rollers arranged at an interval of 50% to 99% of the thickness of the thermal transfer image receiving sheet, and performing a calendar process. As the thermal transfer image receiving sheet, the same one as described above can be used. According to the method for producing a thermal transfer image receiving sheet of the present invention, a thermal transfer image receiving sheet capable of suppressing printing unevenness during image formation is obtained.

  Each layer of the thermal transfer image-receiving sheet can be formed using a known method such as roll coating, bar coating, gravure coating, gravure reverse coating, die coating, slide coating, and curtain coating. In the present invention, on the surface side having the receiving layer, it is preferable to form all the layers constituting the receiving layer from the hollow layer by aqueous coating.

  The process of performing the calendar process can be performed in the same manner as described in the “calendar process” of the thermal transfer image receiving sheet.

The thermal transfer image receiving sheet calendering method The thermal transfer image receiving sheet calendering method of the present invention comprises a base material, a thermal transfer image receiving sheet comprising a hollow layer and a receiving layer in this order on the base material. It is characterized in that it is sandwiched between two support rollers arranged at an interval of 50% to 99% of the thickness of the material and subjected to calendar processing. According to the calendering method for a thermal transfer image receiving sheet of the present invention, it is possible to modify the surface state without crushing the hollow layer of the thermal transfer image receiving sheet, and to suppress uneven printing during image formation.

  In the production of the thermal transfer image-receiving sheet, for example, when the drying is performed at a high temperature of 80 ° C. or higher, the coated surface quality is deteriorated. In such a case, the performance to be obtained by drying at a high temperature, such as releasability, may not be sufficient. Even in such a case, the release property can be compensated by performing the calendar process.

  As the thermal transfer image receiving sheet, the same one as described above can be used. Further, the process of performing the calendar process can be performed in the same manner as described in the “calendar process” of the thermal transfer image receiving sheet.

Thermal transfer ink sheet The thermal transfer ink sheet used together with the thermal transfer image-receiving sheet of the present invention is provided with a heat transferable color material layer on one side of the base sheet and a heat resistant slipping layer on the other side of the base sheet. It is preferable to have a layer structure. Hereinafter, each layer constituting the thermal transfer ink sheet will be described.

As the material of the base sheet constituting the thermal transfer ink sheet used in the present invention, a conventionally known material can be used, and even if it is other than that, it has a certain degree of heat resistance and strength. Can be used. For example, polyethylene terephthalate, polyester, polypropylene, polycarbonate, polyethylene, polystyrene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyimide, nylon, cellulose acetate, ionomer and other resin films, condenser paper, paraffin paper, and other non-woven fabrics Etc. These may be used alone, or a laminate in which these are arbitrarily combined may be used. Among these, polyethylene terephthalate which is a versatile plastic that can be thinned and is inexpensive is preferable.

  The thickness of the base sheet can be appropriately selected according to the material so that the strength, heat resistance and the like are appropriate, but is usually preferably about 0.5 to 50 μm, more preferably 1 to 20 μm, and further Preferably it is 1-10 micrometers.

  The base sheet may be subjected to a surface treatment in order to improve adhesion with an adjacent layer. As the surface treatment, known resin surface modification techniques such as corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, chemical treatment, plasma treatment, and grafting treatment are applied. can do. Only one type of the surface treatment may be applied, or two or more types may be applied.

  Furthermore, it is also possible to apply and form an adhesive layer on the base sheet as an adhesive treatment of the base sheet. An adhesion layer can be formed from the following organic materials and inorganic materials, for example. Examples of the organic material include polyester resins, polyacrylate resins, polyvinyl acetate resins, polyurethane resins, styrene acrylate resins, polyacrylamide resins, polyamide resins, polyether resins, polystyrene resins, Examples thereof include polyethylene resins, polypropylene resins, polyvinyl chloride resins, polyvinyl alcohol resins, polyvinyl pyrrolidone and vinyl resins such as modified products thereof, and polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral. Examples of the inorganic material include silica (colloidal silica), alumina or alumina hydrate (alumina sol, colloidal alumina, cationic aluminum oxide or hydrate, suspicion bakumaite, etc.), aluminum silicate, magnesium silicate, magnesium carbonate, oxidation Examples thereof include ultrafine particles of colloidal inorganic pigments such as magnesium and titanium oxide.

  Moreover, when manufacturing a plastic film by extending | stretching as said surface treatment, a primer liquid can be apply | coated to an unstretched film and it can also carry out by extending | stretching after that (primer process).

Thermal transferable color material layer The thermal transfer ink sheet used in the present invention is provided with a thermal transferable color material layer on one surface of a substrate sheet. When the thermal transfer ink sheet is a sublimation type thermal transfer ink sheet, a layer containing a sublimation dye is formed as the thermal transferable color material layer, and when the thermal transfer type thermal transfer ink sheet is a hot melt composition containing a colorant A layer containing a heat-meltable ink is formed. A layer region containing a sublimable dye and a layer region containing a heat-meltable ink composed of a heat-melting composition containing a colorant are provided in a surface sequence on a continuous base sheet. Also good.

  As the material of the heat transferable color material layer, conventionally known dyes can be used, but those having good characteristics as a printing material, for example, having a sufficient coloring density and changing color due to light, heat, temperature, etc. Preferred are diarylmethane dyes, triarylmethane dyes, thiazole dyes, merocyanine dyes, pyrazolone dyes, methine dyes, indoaniline dyes, acetophenone azomethine, pyrazoloazomethine, imidazolazomethine, imidazoazomethine, pyridone Azomethine dyes such as azomethine, xanthene dyes, oxazine dyes, cyanostyrene dyes such as dicyanostyrene and tricyanostyrene, thiazine dyes, azine dyes, acridine dyes, benzeneazo dyes, pyridoneazo, thiophenazo, iso Thiazoleazo, pyro Azo dyes such as ruazo, pyrazole azo, imidazole azo, thiadiazole azo, triazole azo, and disazo, spiropyran dyes, indolinospiropyran dyes, fluorane dyes, rhodamine lactam dyes, naphthoquinone dyes, anthraquinone dyes, quinophthalone dyes And dyes. Specifically, as a red dye, MS Red G (manufactured by Mitsui Toatsu Chemical Co., Ltd.), Macrolex Red Violet R (manufactured by Bayer), CeresRed 7B (manufactured by Bayer), Samaron Red F3BS (manufactured by Mitsubishi Chemical), etc. Is mentioned. Examples of yellow dyes include Holon Brilliant Yellow 6GL (manufactured by Clariant), PTY-52 (manufactured by Mitsubishi Kasei), Macrolex Yellow 6G (manufactured by Bayer), and the like. As blue dyes, Kayaset Blue 714 (manufactured by Nippon Kayaku Co., Ltd.), Waxoline Blue AP-FW (manufactured by ICI), Holon Brilliant Blue SR (manufactured by Sand Corporation), MS Blue 100 (Mitsui Toatsu Chemical Co., Ltd.) Manufactured), C.I. I. Solvent Blue 22 etc. are mentioned. In addition, the dye contained in the ribbon used by the sublimation type thermal transfer system marketed can also be used.

  Examples of the binder resin for supporting the dye include cellulose resins such as ethyl cellulose resin, hydroxyethyl cellulose resin, ethyl hydroxy cellulose resin, methyl cellulose resin, and cellulose acetate resin, polyvinyl alcohol resin, polyvinyl acetate resin, and polyvinyl butyral resin. And vinyl resins such as polyvinyl acetal resin and polyvinyl pyrrolidone, acrylic resins such as poly (meth) acrylate and poly (meth) acrylamide, polyurethane resins, polyamide resins, and polyester resins. Among these, cellulose-based, vinyl-based, acrylic-based, polyurethane-based, and polyester-based resins are preferable from the viewpoints of heat resistance, dye transferability, and the like.

  Examples of the method for forming the heat transferable color material layer include the following methods. For the heat-transferable colorant layer obtained by adding additives such as a release agent to the above dyes and binder resin, if necessary, dissolved in an appropriate organic solvent such as toluene or methyl ethyl ketone, or dispersed in water. A coating solution (dissolved solution or dispersion) is applied to one surface of a substrate sheet by, for example, a gravure printing method, a reverse roll coating method using a gravure plate, a roll coater, a bar coater, etc., and dried. Can be formed. The heat transferable color material layer has a thickness of about 0.2 to 5.0 μm, and the content of the sublimable dye in the heat transferable color material layer is 5 to 90% by mass, preferably 5 to 70% by mass. It is preferable that

Protective layer The thermal transfer ink sheet used in the present invention may be provided with a protective layer in the surface order on the same side as the thermal transferable color material layer. After the color material is transferred to the thermal transfer image-receiving sheet, the protective layer is transferred to cover the image, whereby the image can be protected from light, gas, liquid, abrasion and the like. Other layers such as an adhesive layer, a release layer, a release layer, or an undercoat layer may be provided as a protective layer.

Heat-resistant slip layer The heat-resistant slip layer is mainly composed of a heat-resistant resin. The heat resistant resin is not particularly limited. For example, polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer resin, polyether resin, polybutadiene resin, styrene-butadiene copolymer resin, Acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetate propionate resin, cellulose acetate butyrate resin, cellulose acetate-hydrodiene Phthalate resin, cellulose acetate resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, polycarbonate resin, Fine chlorinated polyolefin resins.

  The heat resistant slipping layer may be formed by blending additives such as a slipperiness imparting agent, a crosslinking agent, a release agent, an organic powder, and an inorganic powder in addition to the above heat resistant resin.

  In general, the heat-resistant slipping layer is prepared by adding the above-mentioned heat-resistant resin and the above-mentioned slipperiness-imparting agent and additives that are optionally added to the solvent, and dissolving or dispersing each component to form a heat-resistant slipping layer coating solution. After the preparation, the heat resistant slipping layer coating solution can be applied on a substrate and dried. As the solvent in the heat resistant slipping layer coating solution, the same solvents as those in the dye ink can be used.

Examples of the coating method of the heat resistant slipping layer coating liquid include wire bar coating, gravure printing, screen printing, reverse roll coating using a gravure plate, and gravure coating is particularly preferable. Heat-resistant slip layer coating solution, dry coating amount is preferably 0.1 to 3 g / ^{m 2,} more preferably may be applied so as to be 1.5 g / ^{m 2} or less.

Image Forming Method In the image forming method using the thermal transfer image receiving sheet of the present invention, the thermal transfer image receiving sheet and the thermal transfer ink sheet containing a heat diffusible dye are overlaid and heated in accordance with a recording signal, thereby transferring the thermal transfer image. An image can be formed by transferring the thermal diffusible dye contained in the ink sheet to the thermal transfer image-receiving sheet.

  As a thermal transfer recording apparatus that can be used in such an image forming method, a known apparatus can be used and is not particularly limited. In the present invention, a commercially available thermal transfer recording apparatus can be used, and examples thereof include a sublimation thermal transfer printer (manufactured by ALTECH ADS (model: MEGAPICEL III), manufactured by DNP Photo Lucio (model: DS40)).

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples. In addition, the mass part of description described was described by solid content, and it diluted with the pure water as needed.

Example 1
Using RC paper (manufactured by Mitsubishi Paper Industries Co., Ltd.) as a base material for producing the thermal transfer image-receiving sheet 1, the coating liquid 1 for the hollow layer A, the coating liquid 1 for the hollow layer B, the coating liquid 1 for the primer layer, and the receptor having the following composition the layers coating liquid 1 was heated respectively to 40 ° C., using a slide coating, the coating amount after drying respectively ^{2.0g / m 2, 3.0g / m} 2, 3.0g / m 2, 3.0g / M ² , coated at the same time, cooled at 5 ° C. for 30 seconds, dried at 50 ° C. for 2 minutes, and heat-transfer image-receiving sheet (layer constitution: substrate / hollow layer A / hollow layer B / primer Layer / receptive layer). The coating speed was 20 m / min. This thermal transfer image receiving sheet has a layer structure as shown in FIG. 1, and the total thickness of the thermal transfer image receiving sheet was 230 μm.
Composition of hollow layer A coating solution 1 (for lower layer) Hollow particles (volume average particle size: 0.5 μm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 55 parts by mass Gelatin (Nitta Gelatin Co., Ltd., trade name: N1236) 26 parts by mass Binder resin (Styrene / acrylic resin, Shin-Nakamura Chemical Co., Ltd., trade name: New Coat B-13) 8 parts by mass Binder resin (styrene / acrylic resin, manufactured by BASF Japan Ltd., trade name: Jonkrill 62J) 8 parts by mass
Composition of hollow layer B coating solution 1 (for upper layer) Hollow particles (volume average particle size: 0.5 μm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 59 parts by mass Gelatin (Nitta Gelatin Co., Ltd., trade name: N1236) 28 parts by mass Binder resin (styrene / acrylic resin, Shin-Nakamura Chemical Co., Ltd., trade name: New Coat B-13) 5 parts by mass Binder resin (styrene / acrylic resin, manufactured by BASF Japan Ltd., trade name: Jonkrill 62J) 8 parts by mass
Composition of coating liquid 1 for primer layer : Hollow particles (crosslinked hollow particles, volume average particle size: 0.4 μm, average hollow ratio: 39%, manufactured by Rohm and Haas Co., Ltd., trade name: OA-39) 70 parts by mass・ Gelatin (made by Nitta Gelatin Co., Ltd., trade name: N1236) 16 parts by mass ・ Fluorescent whitening agent (made by Showa Chemical Industry Co., Ltd., trade name: WN-1) 4 parts by mass ・ Binder resin (styrene / acrylic) Resin, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: New Coat B-13) 2 parts by mass Binder resin (styrene / acrylic resin, manufactured by BASF Japan Ltd., trade name: John Krill 62J) 2 parts by mass
Composition of Receptive Layer Coating Solution 1 Binder Resin 1 100 parts by mass Urethane Associative Thickener (Viscosity: 2000, Viscosity Ratio: 3.0, manufactured by ADEKA Corporation, trade name: UH-526) 6 parts by mass Release agent (silicone dispersion, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-22-3000T / KF410) 11 parts by mass Wax additive (carnauba wax, manufactured by Chukyo Yushi Co., Ltd., trade name: cellosol 524)
7 parts by mass

Preparation of binder resin 1 The binder resin 1 used in the coating solution 1 for the receiving layer was prepared as follows. In a 2.5 L autoclave, 600 g of deionized water, 438.8 g of vinyl chloride monomer (97.5% by mass with respect to all charged monomers), and 2.25 g of potassium persulfate were charged. The reaction mixture was stirred with a stirring blade so as to maintain a rotation speed of 120 rpm, and the temperature of the reaction mixture was raised to 60 ° C. to initiate polymerization. 11.2 g of glycidyl methacrylate (2.5% by mass based on all charged monomers) was continuously added at a rate of 2.8 g / hr from the start of polymerization to 4 hours later, and the vinyl chloride monomer at a polymerization pressure of 60 ° C. The polymerization was stopped when the saturated vapor pressure decreased by 0.6 MPa to obtain a vinyl chloride resin latex.

  The thermal transfer image receiving sheet obtained above is sandwiched between two support rollers arranged at an interval of 180 μm, and the surface temperature of one of the two support rollers (heating roller) is heated to 180 ° C., The thermal transfer image receiving sheet 1 was obtained by performing a calendering process under conditions of a linear pressure of 66 kg / cm and a line speed of 150 m / min.

With easy-adhesion treated polyethylene terephthalate film having a thickness of 4.5μm as prepared substrate sheet of the thermal transfer ink sheet 1, on this, the heat-resistant slip layer coating solution having the following composition to dry 0.8 g / m ² This was applied to form a heat-resistant slipping layer.
Composition of coating solution 1 for heat resistant slipping layer / polyvinyl acetal (Sekisui Chemical Co., Ltd., trade name: ESREC KS-1)
60.6 parts by mass / polyisocyanate (Dainippon Ink Chemical Co., Ltd., trade name: Barnock D750)
8.4 parts by mass. Silicone resin fine particles (Momentive Performance Materials Japan G.K., trade name: Tospearl 240, average particle size: 4 μm, polygonal shape) 1 part by mass. Zinc stearyl phosphate (LBT-1830 purification, Sakai Chemical Industry Co., Ltd.) 10 parts by mass, zinc stearate (SZ-PF Sakai Chemical Industry Co., Ltd.) 10 parts by mass, polyethylene wax (Polywax 3000, manufactured by Toyo Petrolite Co., Ltd.) 3 parts by mass Ethoxylated alcohol-modified wax (manufactured by Toyo Adre Co., Ltd., trade name: Unitox 750) 7 parts by mass, 200 parts by mass of methyl ethyl ketone, 100 parts by mass of toluene

Next, a primer layer coating liquid having the following composition is applied to a part of the surface opposite to the side on which the heat-resistant slip layer of the substrate is provided, so that the dry coating amount is 0.10 g / m ² . The primer layer was formed by drying. Subsequently, a yellow color material layer coating solution, a magenta color material layer coating solution, and a cyan color material layer coating solution having the following composition are dried on the primer layer so that the amount is 0.6 g / m ² when dried. The yellow color material layer, the magenta color material layer, and the cyan color material layer were formed by coating and drying repeatedly in order.
Coating liquid for primer layer / Colloidal silica (particle diameter 4-6 nm, solid content 10%, manufactured by Nissan Chemical Industries, Ltd., trade name: Snowtex OXS) 30 parts by mass / binder resin (polyvinylpyrrolidone resin, K-90, (Made by ISP) 3 parts by weight, 50 parts by weight of water, 17 parts by weight of isopropyl alcohol

Composition of coating solution for yellow color material layer: 2.5 parts by weight of disperse dye (dispersed yellow 201) 2.5 parts by weight of disperse dye (yellow dye represented by the following chemical formula)
・ Binder resin (polyvinyl acetal resin, KS-5, manufactured by Sekisui Chemical Co., Ltd.)
4.5 parts by mass, polyethylene wax 0.1 parts by mass, methyl ethyl ketone 45.0 parts by mass, toluene 45.0 parts by mass
Composition of coating solution for magenta color material layer / Dye represented by the following chemical formula: 2.0 parts by mass
・ Binder resin (polyvinyl acetal resin, KS-5, manufactured by Sekisui Chemical Co., Ltd.)
4.5 parts by mass, alkyl-modified silicone oil (KF-412, manufactured by Shin-Etsu Silicone Co., Ltd.)
0.1 part by mass, polyethylene wax 0.1 part by mass, methyl ethyl ketone 45.0 parts by mass, toluene 45.0 parts by mass
Composition of the coating solution for the cyan color material layer 2.0 parts by mass of the dye represented by the following chemical formula
・ Binder resin (polyvinyl acetal resin, KS-5, manufactured by Sekisui Chemical Co., Ltd.)
4.5 parts by mass, alkyl-modified silicone oil (KF-412, manufactured by Shin-Etsu Silicone Co., Ltd.)
0.1 part by mass, polyethylene wax 0.1 part by mass, methyl ethyl ketone 45.0 parts by mass, toluene 45.0 parts by mass

In addition, a protective layer coating solution having the following composition is applied to the other part of the other side of the base sheet on which the heat-resistant slipping layer is provided, so that the amount is 1.5 g / m ² when dried. Dried to form. Thereby, a heat-resistant slipping layer is provided on one surface of the base material, and a primer layer and a heat transferable color material layer (Y, M, C) are laminated in this order on a part of the other surface of the base material, A thermal transfer ink sheet 1 was obtained in which a protective layer was provided on another part of the other surface of the substrate.
Composition of coating liquid for protective layer / Acrylic resin (Mitsubishi Rayon Co., Ltd., trade name: Dianar BR-83)
69.6 parts by mass-Acrylic copolymer reactively bonded with a reactive ultraviolet absorber (trade name: UVA635L, manufactured by BASF Japan) 17.4 parts by mass-silica (manufactured by Fuji Silysia Co., Ltd., trade name: Silicia 310) 25 parts by mass, 100 parts by mass of methyl ethyl ketone, 100 parts by mass of toluene

Example 2
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Example 3
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Example 4
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Example 5
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Example 6
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Example 7
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Example 8
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Example 9
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Example 10
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Comparative Example 1
A thermal transfer image receiving sheet was produced in the same manner as in Example 1 except that the calendar process was not performed.

Comparative Example 2
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Comparative Example 3
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1.

Comparative Example 4
A thermal transfer image-receiving sheet was produced and subjected to calendar processing in the same manner as in Example 1 except that the calendar processing conditions were changed as shown in Table 1. The interval between the support rollers of “*” means that no member for adjusting the interval between the two support rollers is provided.

Table 1 shows the calendar processing conditions of the above-described examples and comparative examples.

Evaluation of Thermal Transfer Image Receiving Sheet The surface state of the thermal transfer image receiving sheet produced in Example 1 and Comparative Example 1 was evaluated. Further, the thermal transfer image-receiving sheets produced in the above examples and comparative examples were subjected to printing unevenness evaluation, roller mark evaluation, image density evaluation, and releasability evaluation. In addition, the thickness of the thermal transfer image-receiving sheet obtained in Examples 1 to 10 and Comparative Examples 1 to 3 was 230 μm, which was not changed from that before the calendar process. On the other hand, the thickness of the thermal transfer image receiving sheet obtained in Comparative Example 4 was 220 μm, and the thickness of the thermal transfer image receiving sheet was reduced by calendaring.

Surface Condition Evaluation The surface of the thermal transfer image-receiving sheet produced in Example 1 and Comparative Example 1 was observed by SEM (trade name: S-4800 TYPE-I, manufactured by Hitachi High-Technologies Corporation) (acceleration voltage: 1 kV, magnification) : 3000). Surface images of the thermal transfer image receiving sheets of Example 1 and Comparative Example 1 are shown in FIGS. 4 and 5, respectively. While the surface of the thermal transfer image-receiving sheet of Example 1 shown in FIG. 4 could not be confirmed, cracks could be confirmed on the surface of the thermal transfer image-receiving sheet of Comparative Example 1 shown in FIG.

Evaluation of printing unevenness Using the thermal transfer image-receiving sheet prepared above, the thermal transfer ink sheet 1 prepared above, and a sublimation thermal transfer printer (manufactured by DNP Photolcio, model: DS40), an RGB value of 135 (15 × An intermediate density gray solid image was printed at n, n = 9), and the print unevenness was visually evaluated according to the following criteria.
Evaluation criteria 5: No printing unevenness was observed.
4: At first glance, unevenness was not observed, but slight unevenness was observed when viewed close to each other.
3: At first glance, no unevenness was observed, but a slight unevenness was observed when viewed close to each other.
2: Some printing unevenness was recognized at first glance.
1: Print irregularities were clearly observed at first glance.

Roller Mark Evaluation Using the thermal transfer image-receiving sheet prepared above, the thermal transfer ink sheet 1 prepared above, and a sublimation thermal transfer printer (manufactured by DNP Photolcio, model: DS40), the RGB value is 135 (15 × An intermediate density gray solid image was printed at n, n = 9), and the presence or absence of roller marks was visually evaluated according to the following criteria.
Evaluation criteria 4: No roller marks were observed.
3: Slight roller marks were observed.
2: Although roller marks were observed, there was no problem in actual use.
1: At first glance, roller marks were observed.

Image Density Evaluation Using the thermal transfer image-receiving sheet prepared above, the thermal transfer ink sheet 1 prepared above, and a sublimation thermal transfer printer (manufactured by DNP Photolcio, model: DS40), an RGB value of 15 × n ( n = 0 to 17) 18 gradation gradation image is printed, and a value at which the optical reflection density is maximized by an optical densitometer (spectrolino manufactured by Gretag Macbeth) (Ansi-A, D65)) is measured. The value (optical density) was shown (max). Moreover, the OD value of the gray image (n = 16) and (OD _1), were evaluated highlight characteristic from the difference (.DELTA.OD _2-1) with OD value of the gray image _{(n = 17) (OD 2} ) (HL ).
・Evaluation criteria (max)
5: OD value was 1.95 or more 4: OD value was 1.90 or more and less than 1.95 3: OD value was 1.85 or more and less than 1.90 2: OD value was 1 .80 or more and less than 1.85 1: OD value was less than 1.80 ・Evaluation criteria (HL)
3: .DELTA.OD _2-1 was less than 0.02.
2: .DELTA.OD _2-1 is less than 0.02 or more 0.03.
1: ΔOD _2-1 was 0.03 or more.

Evaluation of releasability Using the thermal transfer image receiving sheet prepared above, the thermal transfer ink sheet 1 prepared above, and a sublimation thermal transfer printer (manufactured by DNP Photolcio, model: DS40), a solid black image was printed. Then, sensory evaluation was performed on the peeling sound generated at that time. Similarly, after leaving for 3 hours in a high-temperature and high-humidity environment at 40 ° C. and 85% RH), a solid black image was printed in that environment, and the peeling sound generated at that time was subjected to sensory evaluation.
Evaluation criteria 5: No peeling sound was heard.
4: A slight peeling sound was heard at the time of printing the third color, but there was no practical problem.
3: A large peeling sound was heard at the time of printing the third color, and there was a problem in practical use.
2: A peeling sound was heard at the time of printing the 2nd color.
1: Could not print.

Table 2 shows the results of the above evaluations. It can be seen that the thermal transfer image-receiving sheet of the present invention has no roller marks at the time of image formation and can suppress uneven printing as compared with the thermal transfer image-receiving sheet of the comparative example.

10 Thermal transfer image-receiving sheet 11 Base material 12 Hollow layer A (lower layer)
13 Hollow layer B (upper layer)
14 Primer Layer 15 Receiving Layer 20 Thermal Transfer Image Receiving Sheet 21 Support Roller 22 Support Roller (Heating Roller)
23 Distance between two supports 24 Thickness of thermal transfer image-receiving sheet

Claims (12)

A step of preparing a thermal transfer image receiving sheet comprising a base material, and a hollow layer and a receiving layer in this order on the base material;
Sandwiching the thermal transfer image receiving sheet by two support rollers arranged at an interval of 50% to 99% of the thickness of the thermal transfer image receiving sheet, and performing a calendar process;
A process for producing a thermal transfer image-receiving sheet, comprising:   The method for producing a thermal transfer image receiving sheet according to claim 1, wherein an interval between the two support rollers is 60% to 95% of a thickness of the thermal transfer image receiving sheet.   The method for producing a thermal transfer image receiving sheet according to claim 2 or 3, wherein a surface temperature of at least one of the two support rollers is 150 ° C to 250 ° C.   The manufacturing method of the thermal transfer image receiving sheet as described in any one of Claims 1-3 in which the said receiving layer contains binder resin and a mold release agent.   The method for producing a thermal transfer image receiving sheet according to claim 4, wherein the binder resin comprises at least one selected from the group consisting of a vinyl chloride resin, a polyester resin, and an acrylic resin.   The method for producing a thermal transfer image receiving sheet according to claim 4 or 5, wherein the release agent comprises a silicone dispersion.   The method for producing a thermal transfer image receiving sheet according to any one of claims 4 to 6, wherein the receiving layer further comprises a wax additive and / or a urethane associative thickener.   The method for producing a thermal transfer image receiving sheet according to claim 1, wherein the hollow layer comprises hollow particles.   The method for producing a thermal transfer image receiving sheet according to any one of claims 1 to 8, wherein all layers constituting the surface side having the receiving layer on the substrate are formed by aqueous coating.   Two supports in which a base material, and a thermal transfer image receiving sheet having a hollow layer and a receiving layer in this order on the base material are arranged at an interval of 50% to 99% of the thickness of the thermal transfer image receiving sheet A calendering method for a thermal transfer image receiving sheet, wherein the calendering process is performed by being sandwiched between rollers.   The calendering method for a thermal transfer image receiving sheet according to claim 10, wherein an interval between the two support rollers is 60% to 95% of a thickness of the thermal transfer image receiving sheet.   The calendering method for a thermal transfer image receiving sheet according to claim 10 or 11, wherein the surface temperature of at least one of the two support rollers is 150 ° C to 250 ° C.