Thermosensitive recording medium and image recording method

Abstract

A thermosensitive recording medium having, in a plan view, a first direction and a second direction perpendicular to the first direction, is provided that includes: a support including a first surface and a second surface opposite to the first surface; a thermosensitive layer arranged in a partial region of the first surface of the support; a protective layer arranged on at least a top surface of the thermosensitive layer; and a cleaning layer arranged in another partial region of the first surface of the support. The first surface of the support includes an exposed part being exposed from the thermosensitive layer, the cleaning layer, and the protective layer, and in a cross-sectional view obtained by cutting the thermosensitive recording medium in the first direction at a predetermined position in the second direction, the thermosensitive layer and the cleaning layer are arranged in different regions.

Description

FN202501297[DESCRIPTION][Title of Invention]THERMOSENSITIVE RECORDING MEDIUM AND IMAGE RECORDING METHOD [Technical Field]

[0001] The present disclosure relates to a thermosensitive recording medium and an image recording method.[Background Art]

[0002] Conventionally, there is a widely known thermosensitive recording medium including, on a support such as paper and synthetic paper, a thermosensitive layer utilizing a color-developing reaction of an electron-donating compound and an electron-accepting compound. The conventional thermosensitive recording medium is prepared by applying and subsequently drying a thermosensitive layer forming liquid in which an electron-donating compound and an electron-accepting compound are blended with a resin such as polyvinyl alcohol, a pigment such as calcium carbonate, a dispersant such as a surfactant, and the like, and the resulting blend is dispersed into fine particles, over the entire surface of the support by an application method such as an air-knife coater, a bar coater, a blade coater, a curtain coater, or gravure printing.

[0003] In preparing such conventional thermosensitive recording medium, applying the thermosensitive layer forming liquid over the entire surface of the support leads to waste of the thermosensitive layer forming liquid applied on non-printed portions, hence increased costs and environmental impact. In a case where a thermosensitive recording medium with a transparent support is used as a packaging material for various types of containers such as PET bottles, when the thermosensitive layer is formed over the entire surface of the support, it is difficult to see the contents inside the packaging. In heat-sealing the thermosensitive recording medium to package a container or the like, when the thermosensitive layer is formed over the entire surface of the support, color development may occur due to the heat in the heat-sealing process.

[0004] Accordingly, a thermosensitive recording medium has been proposed in which a thermosensitive layer forming liquid is applied on a partial region of a support that requires printing for reducing an amount of the thermosensitive layer forming liquid in non-printed portions, thus reducing costs and an environmental impact. In a case where a transparent support is used for such thermosensitive recording medium, it is possible to visually check the inside of a packaging material through a region on the support without the thermosensitive layer, and it is also possible to reduce color development due to heat during heat-sealing.

[0005] FN202501297As a technology for providing a thermosensitive layer on a partial region of a support, a thermosensitive film in which a thermosensitive layer is partially provided on at least one surface of a substrate, and a protective layer is covered over the entire surface of the thermosensitive layer has been proposed (see PTL 1). This proposed thermosensitive film attempts to suppress wear of a protective layer of a thermal head caused by contact with the thermosensitive film during printing.[Citation List][Patent Literature][PTL 1]Japanese Unexamined Patent Application Publication No. 2021-45972 [Summary of Invention] [Technical Problem]

[0006] An object of the present disclosure is to provide a thermosensitive recording medium which can reduce printing defects caused by adhesion of head residue.[Solution to Problem]

[0007] Embodiments of the present disclosure provides a thermosensitive recording medium having, in a plan view, a first direction and a second direction perpendicular to the first direction, that includes: a support including a first surface and a second surface opposite to the first surface; a thermosensitive layer arranged in a partial region of the first surface of the support; a protective layer arranged on at least a top surface of the thermosensitive layer; and a cleaning layer arranged in another partial region of the first surface of the support, said another partial region being different from the partial region in which the thermosensitive layer is arranged. The first surface of the support includes an exposed part being exposed from the thermosensitive layer, the cleaning layer, and the protective layer, and in a cross-sectional view obtained by cutting the thermosensitive recording medium in the first direction at a predetermined position in the second direction, the thermosensitive layer and the cleaning layer are arranged in different regions.[Advantageous Effects of Invention]

[0008] According to the present disclosure, a thermosensitive recording medium which can reduce printing defects caused by adhesion of head residue is provided.[Brief Description of Drawings]

[0009] A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.FIG. 1 A is a schematic top view of an example of a first surface of a thermosensitiveFN202501297 recording medium according to a first embodiment of the present disclosure.FIG. IB is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IB-IB of FIG. 1A.FIG. 2A is a schematic top view of another example of the first surface of the thermosensitive recording medium according to the first embodiment of the present disclosure.FIG. 2B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IIB-IIB of FIG. 2A.FIG. 3 A is a schematic top view of another example of the first surface of the thermosensitive recording medium according to the first embodiment of the present disclosure.FIG. 3B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IIIB-IIIB of FIG. 3 A.FIG. 4A is a schematic top view of another example of the first surface of the thermosensitive recording medium according to the first embodiment of the present disclosure.FIG. 4B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IVB-IVB of FIG. 4A.FIG. 5 is a diagram illustrating a relationship in size among a support 1, a protective layer 3, and a cleaning layer 4 in FIG. 1 A.FIG. 6 is a diagram illustrating a relationship in size among a support 1, a protective layer 3, and a cleaning layer 4 in FIG. 3 A.FIG. 7A is a schematic top view of an example of a first surface of a thermosensitive recording medium according to a second embodiment of the present disclosure.FIG. 7B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line VIIB-VIIB of FIG. 7A.FIG. 8A is a schematic top view of another example of the first surface of the thermosensitive recording medium according to the second embodiment of the present disclosure.FIG. 8B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line VIIIB-VIIIB of FIG. 8 A.FIG. 9A is a schematic top view of an example of the first surface of the thermosensitive recording medium according to the second embodiment of the present disclosure.FIG. 9B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IXB-IXB of FIG. 9A.FIG. 10A is a schematic top view of an example of the first surface of the thermosensitive recording medium according to the second embodiment of the present disclosure.FIG. 1 OB is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XB-XB of FIG. 10A.FIG. 11 A is a schematic top view of an example of the first surface of the thermosensitive recording medium according to the second embodiment of the present disclosure.FIG. 1 IB is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIB-XIB of FIG. 11 A.FN202501297FIG. 12A is a schematic top view of an example of a first surface of a thermosensitive recording medium according to a third embodiment of the present disclosure.FIG. 12B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIIB-XIIB of FIG. 12A.FIG. 13 A is a schematic top view of an example of the first surface of the thermosensitive recording medium according to the third embodiment of the present disclosure.FIG. 13B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIIIB-XIIIB of FIG. 13 A.FIG. 14A is a schematic top view of an example of the first surface of the thermosensitive recording medium according to the third embodiment of the present disclosure.FIG. 14B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIVB-XIVB of FIG. 14A.FIG. 15A is a schematic top view of an example of the first surface of the thermosensitive recording medium according to the third embodiment of the present disclosure.FIG. 15B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XVB-XVB of FIG. 15 A.FIG. 16A is a schematic top view of an example of the first surface of the thermosensitive recording medium according to the third embodiment of the present disclosure.FIG. 16B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XVIB-XVIB of FIG. 16A.FIG. 17A is a schematic top view of an example of the first surface of the thermosensitive recording medium according to the third embodiment of the present disclosure.FIG. 17B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XVIIB-XVIIB of FIG. 17A.FIG. 18A is a schematic top view of an example of a first surface of a thermosensitive recording medium according to an embodiment of the present disclosure.FIG. 18B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XVIIIB-XVIIIB of FIG. 18 A.FIG. 19A is a schematic top view of an example of a first surface of a thermosensitive recording medium according to an embodiment of the present disclosure.FIG. 19B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIXB-XIXB of FIG. 19A.FIG. 20A is a schematic top view of an example of a first surface of a thermosensitive recording medium according to an embodiment of the present disclosure.FIG. 20B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XXB-XXB of FIG. 20A.FIG. 21 A is a schematic top view of an example of a first surface of a thermosensitive recording medium according to Comparative Example 1.FIG. 2 IB is a schematic cross-sectional view of the thermosensitive recording medium in theFN202501297 thickness direction, taken along line XXIB-XXIB of FIG. 21A.FIG. 22 is a schematic top view of an example of a first surface of a thermosensitive recording medium according to an embodiment of the present disclosure.The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views. [Description of Embodiments]

[0010] In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.An example of general methods for partial printing includes gravure printing. In gravure printing, liquid ink is supplied to a surface of a cylinder with a printing plate including many tiny depressions formed thereon called a cell formed on the surface according to a pictorial pattern, and the ink on the surface other than the depressions is scraped off to transfer only the ink in the cell to a printed material. A doctor used for such scraping is pressed against the printing plate at an appropriate angle and with an appropriate pressure during printing to ensure that a blade edge is in uniform contact with the printing plate. As the printing plate rotates during printing, the blade edge of the doctor wears down, and ink in a non-image area cannot be completely scraped off, so that a phenomenon known as a so-called "plate fogging" may occur in which ink remains on the printing plate outside an image area.

[0011] The inventors of the present invention conducted extensive research and found that there occurred a problem that a layer transferred to a substrate due to plate fogging had poor filmforming properties, and thus, in printed with a thermal printer, the layer was rubbed by a thermal head and adhered to the head as residue. The residue adhering to a heating element of the head causes faint printing. The inventors also found that such a phenomenon tended to occur particularly after a doctor blade became worn due to continuous production.

[0012] Conventionally, a thermosensitive recording material is generally used in which at least a thermosensitive layer is provided on the entire surface of an upper layer of a support, and a protective layer is further provided on the thermosensitive layer. In recent years, a thermosensitive recording medium including a thermosensitive layer provided at leastFN202501297 partially and a protective layer provided partially to cover the thermosensitive layer is used.

[0013] When the thermosensitive layer and the protective layer are partially provided, the amount used can be reduced, and when the thermosensitive layer is not provided in a heat-sealed portion of a heat-sealed packaging material, thermal color development by sensing heat by heat sealing can be eliminated. When the thermosensitive layer having any shape is partially provided, the design can be improved, and particularly when a transparent substrate is used as the support, there are provided various effects such as a good visibility of an areas without the thermosensitive layer, and thus, such a transparent substrate is increasingly used.

[0014] When a color ink layer is provided simultaneously with the thermosensitive layer and the protective layer, a thermosensitive recording medium with various designs can be provided. A method for partially providing the thermosensitive layer and the protective layer can include various printing methods. Among such printing methods, a flexographic printing method and a gravure printing method are particularly preferred for partially providing the thermosensitive layer and the protective layer in addition to the color ink layer.

[0015] On the other hand, the inventors also found that when the thermosensitive layer and the protective layer were partially provided and printing was performed with a thermal head, printing defects were likely to occur due to head residue caused by foreign matters entered from the outside or trace amounts of foreign matters adhered to the film.

[0016] Conventionally, a protective layer suitable for head matching is generally provided to improve the printing characteristics of a thermal head and to provide a function for removing head residue. However, the investigations of the inventors revealed that if a protective layer was partially provided, the function of removing head residue might not be sufficient.

[0017] It is also possible to provide only a protective layer over the entire surface, but the major advantage of providing a thermosensitive layer only partially is that it is possible to minimize the amount of material used and allow for designs using color ink layers, and to provide a thermosensitive recording medium with excellent design when a thermosensitive layer is provided partially. In particular, when a transparent support is used, the transparency of the support without the thermosensitive layer and the color ink layer has the advantage that the contents can be easily seen when used as a packaging material or the like.

[0018] A layer such as the thermosensitive layer and the protective layer contains at least a color former, a pigment, a lubricant, and the like, which reduces transparency to a certain extent. Therefore, in consideration of the visibility of the transparent portion, it is preferable to provide the thermosensitive layer and the protective layer in the minimum area necessary forFN202501297 display.

[0019] Furthermore, in the case of packaging materials, an area near ends in a width direction and in a flow direction is often not used in the final form, so if the protective layer or the like is provided outside the range, it is possible to avoid impairing the visibility of the final product.

[0020] By contrast, the thermosensitive recording medium according to the present disclosure can employ the configuration described below to reduce printing defects caused by adhesion of head residue without compromising design.

[0021] Embodiments of the present disclosure will be described below with reference to the drawings.

[0022] It is noted that the present disclosure is not limited to the embodiments described below, and can be modified within the scope of what a person skilled in the art can conceive, such as other embodiments, additions, modifications, or deletions, and any aspect is within the scope of the present disclosure as long as it achieves the functions and effects of the present disclosure.

[0023] The dimensions, the materials, the shapes, the relative arrangements, and the like of the components described in the embodiments are merely illustrative examples and are not intended to limit the scope of the present disclosure unless otherwise specified. It is noted that the sizes, the positional relationships, and the like of components illustrated in each drawing may be exaggerated for clarity of explanation. In the following description, the same names and symbols indicate the same or similar components, and detailed descriptions will be omitted as appropriate. To avoid overly complicated drawings, schematic diagrams with some omitted elements may be used, and end views illustrating only the cut surface may be employed for cross-sectional views.

[0024] In the present disclosure, polygons such as rectangles, triangles, and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons are, for example, rounded, chamfered, de-angled, or de-rounded. Shapes in which processing is applied not only to the corners (i.e., ends of the sides) but also to the middle portions of the sides are also referred to as polygons. That is, a shape partially processed while still retaining a polygonal shape as its base is intended to be included in the interpretation of "polygon" described in the present disclosure.

[0025] The same is true not only of polygons, but also of words expressing specific shapes such as trapezoids, circles, and irregular shapes. The same is true in dealing with each side includedFN202501297 in the shape. That is, even if the corners or middle part of a certain side are processed, a "side" includes the processed parts in interpreting the "side". It is noted that in distinguishing a "polygon" or a "side" without any partially processed parts from a processed shape, the word "strict" will be added to express a quadrangle without any partially processed parts, for example, as a "strict quadrangle".

[0026] In the following description, terms indicating specific directions or positions (for example, "upper", "lower", "side", "top surface", "bottom surface", "side surface", "X", "Y", "Z", and other terms incorporating such terms) will be used optionally. However, the use of such terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meanings of such terms should not be construed as excessively limiting the technical scope of the present disclosure. For example, when the term "top surface" is used, it does not necessarily mean that the invention must always be used facing upwards. In the embodiments, "cover" is not limited to direct contact, but also includes indirect covering, for example, through another member.

[0027] (Thermosensitive Recording Medium)A thermosensitive recording medium according to the present disclosure is a thermosensitive recording medium having, in a planar view, a first direction and a second direction perpendicular to the first direction, and includes a support including a first surface and a second surface opposite to the first surface; a thermosensitive layer arranged in a partial region of the first surface of the support, a protective layer arranged on at least a top surface of the thermosensitive layer, and a cleaning layer arranged in another partial region of the first surface of the support, different from the partial region in which the thermosensitive layer is arranged. The first surface of the support includes an exposed part being exposed from the thermosensitive layer, the cleaning layer, and the protective layer, and in a cross-sectional view obtained by cutting the thermosensitive recording medium in the first direction at a predetermined position in the second direction, the thermosensitive layer and the cleaning layer are arranged in different regions. The thermosensitive recording medium according to the present disclosure may further include another layer or member as necessary.

[0028] In the thermosensitive recording medium according to the present disclosure, the thermosensitive layer and the protective layer arranged on the top surface of the thermosensitive layer, as well as the cleaning layer, may be arranged at only one location on the first surface of the support, or may be arranged at a plurality of locations, as long as the above-mentioned arrangement of the thermosensitive layer and the cleaning layer is satisfied.

[0029] In the thermosensitive recording medium according to the present disclosure, the exposed part refers to a region in which the thermosensitive layer, the protective layer, the cleaning layer,FN202501297 and optionally the color ink layer are not arranged, and in which the first surface of the support is exposed in a top view of the thermosensitive recording medium. This has the advantage that, when the support is transparent and the thermosensitive recording medium is employed for a packaging material for the various containers or the like, the inside of various containers can be seen.

[0030] In the thermosensitive recording medium according to the present disclosure, the arrangement of the exposed part is not particularly limited and can be selected appropriately depending on the purpose. In the first direction, at least one of a side surface of the thermosensitive layer and a side surface of the protective layer may not be in contact with a side surface of the cleaning layer, and the exposed part may be disposed between the thermosensitive layer and the protective layer, and the cleaning layer in the first direction.

[0031] First EmbodimentThe thermosensitive recording medium according to a first embodiment of the present disclosure has a first direction and a second direction perpendicular to the first direction. In the thermosensitive recording medium according to the first embodiment of the present disclosure, the first direction is preferably coincident with a transport direction in a thermal printer.

[0032] The shape of the thermosensitive recording medium according to the first embodiment of the present disclosure is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a label form, a sheet form, and a roll form.

[0033] The thermosensitive recording medium according to the first embodiment of the present disclosure includes a support, a thermosensitive layer, a protective layer, and a cleaning layer. The first surface of the support includes an exposed part at least partially exposed from the thermosensitive layer, the cleaning layer, and the protective layer, and, in a cross-sectional view obtained by cutting the thermosensitive recording medium in the first direction at a predetermined position in the second direction, the thermosensitive layer and the cleaning layer are arranged in different regions.

[0034] <Support>The support includes a first surface and a second surface opposite the first surface. The support supports the thermosensitive layer, the protective layer, and the cleaning layer, and further, if necessary, another layer or member.

[0035] The shape of the support is not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape include, but are not limited to, polygonalFN202501297 shapes such as a square and a rectangle, a circle, an ellipse, a flat plate, and a sheet form.

[0036] The structure of the support is not particularly limited and can be appropriately selected depending on the purpose. Such a structure may be a single-layer structure or a laminated structure having two or more layers formed of two or more materials.

[0037] The structure of the support is not particularly limited and can be appropriately selected depending on the purpose. Such a structure may be a single-layer structure or a multi-layer structure having two or more layers.

[0038] The dimension of the support is not particularly limited and can be appropriately selected depending on the dimension of the desired thermosensitive recording medium.

[0039] The material of the support is not particularly limited and can be appropriately selected depending on the purpose. Examples of the material include, but are not limited to, paper, synthetic paper, and plastic film.

[0040] The plastic film is not particularly limited and can be appropriately selected depending on the purpose. Examples of the plastic film include, but are not limited to, films formed of polyester resins such as polyethylene terephthalate (PET), polycarbonate, polystyrene (PS), polymethyl methacrylate (PMMA), polyethylene (PE), polypropylene (PP), and polyvinyl chloride. Such plastic films may be used alone or in combination of two or more types.

[0041] Among such plastic films, from the viewpoint of flexibility, polyethylene terephthalate (PET) or polypropylene (PP) is preferred as the support, and biaxially oriented polyethylene terephthalate (PET) is preferred from the viewpoint of excellent strength, heat resistance, dimensional stability, and the like.

[0042] Examples of the support having a multi-layer structure having two or more layers include, but are not limited to, a laminate of cellulose fiber and synthetic paper, and a laminate of cellulose fiber and a plastic film or a laminate of a plastic film and synthetic paper.

[0043] The support may be surface-modified by a corona discharge treatment, an oxidation reaction treatment (for example, chromic acid), an etching treatment, an adhesion enhancing treatment, an antistatic treatment, or the like, for the purpose of improving adhesion to the thermosensitive layer, the protective layer, and the cleaning layer, as well as further if necessary, another layer or member.

[0044] The support may be a white opaque film formed by adding additives such as a white rawFN202501297 material and a filler to the above-mentioned material, or a foamed sheet.

[0045] The support may further contain inorganic materials, organic compounds, and the like, from the viewpoint of improving heat resistance, mechanical strength, and the like.

[0046] The inorganic material contained in the support is not particularly limited and can be appropriately selected depending on the purpose. Examples of the inorganic material include, but are not limited to, glass, quartz, and inorganic single crystals. Such inorganic materials may be used alone or in combination of two or more types.

[0047] The organic compound contained in the support is not particularly limited and can be appropriately selected depending on the purpose. Examples of the organic compound include, but are not limited to, benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, and hindered amine-based compounds. Such organic compounds may be used alone or in combination of two or more types.

[0048] It is preferable that the support is a transparent film because it is possible to easily confirm the contents when the thermosensitive recording medium is used for a packaging material for foods and the like. As used herein, the support being "transparent" means that there is no problem if the haze (turbidity) measured in accordance with ASTM D1003 or ISO 14782 regarding film transparency is about 10% or less, but 5% or less is more preferable. The haze of the support may be measured using a haze meter (for example, device name: HZ-V3, manufactured by Suga Test Instruments Co., Ltd.).

[0049] The average thickness of the support is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoints of transparency and ease of processing, the average thickness is preferably 3 pm or more and 300 pm or less. When the average thickness of the support is 3 pm or more, the strength is high, and when the average thickness is 300 pm or less, the transparency is high and the stiffness is low, so that the processability is good.

[0050] As used herein, the "average thickness" of the support means an average value calculated from the thicknesses at 20 points selected at random in the support, after measuring the thicknesses at such 20 points in the support. The thickness of the support may be measured using a film thickness meter (for example, K-402B STAND and electronic micrometer K351C, manufactured by Anritsu Corporation).

[0051] <Thermosensitive Layer>The thermosensitive layer is arranged in a partial region of the first surface of the support.FN202501297

[0052] As used herein, when the thermosensitive layer is arranged on the "first surface" of the support, this means not only that the thermosensitive layer is laminated directly on one surface of the support, but also that the thermosensitive layer may be laminated on one surface of the support via another layer or member. For example, the thermosensitive layer may be arranged on the top surface of the color ink layer arranged on the support.

[0053] As used herein, when the thermosensitive layer is arranged in a "partial region" of the first surface of the support, this means that the area of the thermosensitive layer is arranged to occupy less than 100% of the total area of the first surface of the support.

[0054] A shape, a structure, a dimension, the number, and arrangement of the thermosensitive layer are not particularly limited as long as the thermosensitive layer is arranged in the partial region on the first surface of the support, and can be appropriately selected depending on the purpose.

[0055] The thermosensitive layer contains an electron-donating compound and an electron-accepting compound, and further optionally contains other components.

[0056] «Electron-Donating Compound»The electron-donating compound is not particularly limited and can be appropriately selected according to the purpose from those typically used in thermosensitive recording media, and examples of the electron-donating compound include, but are not limited to, leuco compounds such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based dyes. Such electron-donating compounds may be used alone or in combination of two or more types.

[0057] Examples of black dye compounds include, but are not limited to, 6-(diethylamino)-2-[3- (trifluoromethyl)anilino]spiro[9H-xanthene-9,3'(l'H)-isobenzofuran]-l'-one, 2'-anilino-3'- methyl-6'-(dipentylamino)spiro[isobenzofuran-l(3H),'-[9H]xanthene]-3-one, 2'-anilino-6'- dibutylamino-3'-methylspiro[phthalide-3, 9'-[9H]xanthene], 2'-anilino-6'-(N-ethyl-N- isopentylamino)-3'-methylspiro[phthalido-3,9'-[9H]xanthene], 2-(phenylamino)-3-methyl-6- [ethyl(p-tolyl)amino]spiro[9H-xanthene-9,l'(3'H)-isobenzofuran]-3'-one, 3-diethylamino-6- methyl-7-anilinofluoran, and 3-dibutylamino-6-methyl-7-anilinofluoran. Such black dye compounds may be used alone or in combination of two or more types.

[0058] Examples of red dye compounds include, but are not limited to, 6'-(diethylamino)-l', 2'- benzofluoran, 9-(N-ethyl-N-isopentylamino)spiro[benzo[a]xanthene-12, 3'-phthalide], 2'- methyl-6'-(N-p-tolyl-N-ethylamino)spiro[isobenzofuran-l(3H), 9'-[9H]xanthene]-3-one, 2'-FN202501297 chloro-6'-(diethylamino)spiro[isobenzofuran-l(3H), 9'-[9H]xanthene]-3-one, 6'- (dibutylamino)-2'-bromo-3'-methylspiro[phthalide-3,9'-xanthene], and 3,3-bis(l-n-butyl-2- methyl-3-indolyl)phthalide. Such red dye compounds may be used alone or in combination of two or more types.

[0059] Examples of blue dye compounds include 3-[4-(diethylamino)-2-hexyloxyphenyl]-3-(l-ethyl- 2-methylindol-3-yl)-4-azaphthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-(l-ethyl-2- methylindol-3-yl)-4-azaphthalide, and 3',6'-bis(diphenylamino)spiro[phthalide-3,9'-xanthene], Such blue dye compounds may be used alone or in combination of two or more types.

[0060] Examples of green dye compounds include l-ethyl-8-[N-ethyl-N-(4-methylphenyl)amino]- 2,2,4-trimethyl-l,2-dihydrospiro[llH-chromeno[2,3-g]quinoline-ll,3'-phthalide], 2'- (dibenzylamino)-6'-(diethylamino)fluoran, and 2'-(N-phenyl-N-methylamino)-6'-(N-p-tolyl- N-ethylamino)spiro[isobenzofuran-l(3H), and 9'-[9H]xanthene]-3-one. Such green dye compounds may be used alone or in combination of two or more types.

[0061] Examples of yellow or orange dye compounds include, but are not limited to, F. Color Yellow- 17, Orange 100, and Orange-DCF. Such yellow or orange dye compounds may be used alone or in combination of two or more types.

[0062] The 50% cumulative volume particle size (D50) of the electron-donating compound is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.05 pm or more and 0.5 pm or less, and more preferably 0.1 pm or more and 0.3 pm or less. The 50% cumulative volume particle size (D50) of the electron-donating compound can be measured, for example, by using a laser diffraction / scattering type particle size distribution measuring device (for example, device name: LA-960, manufactured by Horiba, Ltd.).

[0063] The content of the electron-donating compound is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5% by mass or more and 40% by mass or less, and more preferably 10% by mass or more and 30% by mass or less, based on the total mass of the thermosensitive layer.

[0064] «Electron-Accepting Compound»The electron-accepting compound is not particularly limited as long as the electron-accepting compound has electron-accepting properties allowing the electron-donating compound to react and develop color when heated, and can be appropriately selected according to the purpose from those typically used in thermosensitive recording media, but is preferably a color developer.FN202501297

[0065] The color developer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the color developer include, but are not limited to, phenolic substances, non-phenolic substances, organic or inorganic acidic substances, and esters or salts thereof.

[0066] Specific examples of the color developer include, but are not limited to, gallic acid, salicylic acid, 3-isopropylsalicylic acid, 3-cyclohexylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3,5- di-a-methylbenzylsalicylic acid, 4,4'-isopropylidenediphenol, l,l'-inopropylidenebis(2- chlorophenol), 4,4'-isopropylidenebis(2,6-dibromophenol), 4,4'-isopropylidenebis(2,6- dichlorophenol), 4, 4'-isopropylidenebis(2 -methylphenol), 4,4'-isopropylidenebis(2,6- dimethylphenol), 4,4'-isopropylidenebis(2-tert-butylphenol), 4,4'-sec-butylidenediphenol, 4,4'- cyclohexylidenebisphenol, 4, 4'-cyclohexylidenebis(2 -methylphenol), 4-tert-butylphenol, 4- phenylphenol, 4-hydroxydiphenoxide, a-naphthol, P-naphthol, 3,5-xylenol, thymol, methyl-4- hydroxybenzoate, 4-hydroxyacetophenone, a novolak phenol resin, 2,2'-thiobis (4,6- dichlorophenol), catechol, resorcine, hydroquinone, pyrogallol, phloroglycine, phloroglycine carboxylic acid, 4-tert-octylcatechol, 2,2'-methylenebis (4-chlorophenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2, 2, -dihydroxydiphenyl, ethyl p-hydroxybenzoate, propyl p- hydroxybenzoate, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p-hydroxybenzoic acid-p-chlorobenzyl, p-hydroxybenzoic acid-o-chlorobenzyl, p-hydroxybenzoic acid-p- methylbenzyl, p-hydroxybenzoic acid-n-octyl, benzoic acid, zinc salicylate, 1 -hydroxyl- naphthoic acid, 2-hydroxy-6-naphthoic acid, zinc 2-hydroxy-6-naphthoate, 4- hydroxydiphenyl sulfone, 4-hydroxy-4'-chlorodiphenyl sulfone, bis(4-hydroxyphenyl)sulfide, 2-hydroxy-p-toluic acid, zinc 3,5-di-tert-butylsalicylate, tin 3,5-di-tert -butylsalicylate, tartaric acid, oxalic acid, maleic acid, citric acid, succinic acid, stearic acid, 4-hydroxyphthalic acid, boric acid, thiourea derivatives, 4-hydroxythiophenol derivatives, bis(4-hydroxyphenyl)acetic acid, ethyl bis(4-hydroxyphenyl)acetate, n-propyl bis(4-hydroxyphenyl)acetate, m-butyl bis(4-hydroxyphenyl)acetate, phenyl bis(4-hydroxyphenyl)acetate, benzyl bis(4- hydroxyphenyl)acetate, phenethyl bis(4-hydroxyphenyl)acetate, bis(3-methyl-4- hydroxyphenyl)acetic acid, bis(3-methyl-4-hydroxyphenyl)methyl acetate, bis(3-methyl-4- hydroxyphenyl)n-propyl acetate, l,7-bis(4-hydroxyphenylthio)3,5-dioxaheptane, l,5-bis(4- hydroxyphenylthio)3 -oxaheptane, dimethyl 4-hydroxyphthalate, 4-hydroxy-4'- methoxydiphenyl sulfone, 4-hydroxy-4'-ethoxydiphenyl sulfone, 4-hydroxy-4'- isopropoxy diphenyl sulfone, 4-hydroxy-4'-propoxydiphenyl sulfone, 4-hydroxy-4'- butoxydiphenyl sulfone, 4-hydroxy-4'-isobutoxydiphenyl sulfone, 4-hydroxy-4- butoxydiphenyl sulfone, 4-hydroxy-4'-tert-butoxydiphenyl sulfone, 4-hydroxy-4'- benzyloxydiphenyl sulfone, 4-hydroxy-4'-phenoxydiphenyl sulfone, 4-hydroxy-4'-(m- methylbenzyloxy)diphenyl sulfone, 4-hydroxy-4'-(p-methylbenzyloxy)diphenyl sulfone, 4- hydroxy-4'-(O-methylbenzyloxy)diphenyl sulfone, 4-hydroxy-4'-(p-chlorobenzyloxy)diphenylFN202501297 sulfone, l,l-bis(4-hydroxyphenyl)-l -phenyl ethane, l,l-bis(4-hydroxyphenyl)-3,3,5- trimethylcyclohexane, 1, 1, l-tris(4-hydroxyphenyl)ethane, N,N'-di-[3-(p- toluenesulfonyl)oxy]phenylurea, and [3-(3-phenylureido)phenyl]-4-methylbenzenesulfonate. Such color developers may be used alone or in combination of two or more types.

[0067] The 50% cumulative volume particle size (D50) of the electron-accepting compound is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.05 pm or more and 0.5 pm or less, and more preferably 0.1 pm or more and 0.3 pm or less. The 50% cumulative volume particle size (D50) of the electron-accepting compound can be measured, for example, by using a laser diffraction / scattering type particle size distribution measuring device (for example, device name: LA-960, manufactured by Horiba, Ltd.).

[0068] The content of the electron-accepting compound is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5% by mass or more and 40% by mass or less, and more preferably 10% by mass or more and 30% by mass or less, based on the total mass of the thermosensitive layer.

[0069] The mass ratio between the content of the electron-donating compound and the content of the electron-accepting compound is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of transparency stability, however, the content of the electron-accepting compound is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, and even more preferably 1 part by mass or more and 4 parts by mass or less, per 1 part by mass of the electron-donating compound.

[0070] The average thickness of the thermosensitive layer is not particularly limited and can be selected appropriately optionally, but is preferably 1 pm or more and 20 pm or less, and more preferably 2 pm or more and 10 pm or less.

[0071] As used herein, the "average thickness" of the thermosensitive layer means an average value calculated from the thicknesses at 20 points selected at random in the thermosensitive layer, after measuring the thicknesses at such 20 points in the thermosensitive layer. The thickness of the thermosensitive layer can be measured using a film thickness meter (for example, K- 402B STAND and electronic micrometer K351C, manufactured by Anritsu Corporation). The thickness of the thermosensitive layer may be measured by cutting the thermosensitive recording medium in the thickness direction (lamination direction) using a cross-sectional sample preparation device (for example, Cross Section Polisher SM-09020CP, manufactured by JEOL Ltd.) to expose the cross-section surface, and observing the cross-section surfaceFN202501297 with a scanning electron microscope (SEM) (for example, S-3700, manufactured by Hitachi High-Tech Corporation).

[0072] «Other Components»Other components in the thermosensitive layer are not particularly limited and can be appropriately selected according to the purpose from those typically used in thermosensitive recording media, and examples thereof may include, but are not limited to, photothermal conversion materials, ultraviolet absorbing materials, binder resins, auxiliary additives, heat- fusible substances, lubricants, fillers, ultraviolet absorbing agents, antioxidants, sensitizers, and light stabilizers.

[0073] The contents of other components in the thermosensitive layer are not particularly limited and can be appropriately selected depending on the purpose.

[0074] - Ultraviolet Absorbing Materials -The ultraviolet absorbing materials are not particularly limited and can be appropriately selected depending on the purpose. Examples of the ultraviolet absorbing materials include, but are not limited to, salicylic acid-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and benzotriazole-based ultraviolet absorbers.

[0075] Specific examples of the ultraviolet absorbing materials include, but are not limited to, phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, 2,4- dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4- octoxybenzophenone, 2-hydroxy-4-dodecyl oxybenzophenone, 2,2'-dihydroxy-4- methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy- 5-sulfobenzophenone, bis(2-methoxy-4-hydroxy-5-benzoylphenyl)methane, 2-(2'-hydroxy-5'- methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy- 3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert- butylphenyl)chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5- chlorobenzotri azole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-{2'-hydroxy-3'- (3",4",5",6"-tetrahydrophthalimidomethyl)-5'-methylphenyl}benzotriazole, 2,2'- methylenebis{4 -(1, l,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol}, 2-(2'-hydroxy- 5'-methacryloxyphenyl)-2H-benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, and 2-(5-methyl-2- hydroxyphenyl)benzotriazole. Such ultraviolet absorbing materials may be used alone or in combination of two or more types.

[0076] - Binder Resins -The binder resins are not particularly limited and can be appropriately selected depending onFN202501297 the purpose. Examples of the binder resins include, but are not limited to, thermoplastic resins, thermosetting resins, and photocurable resins. The properties of such resins are not particularly limited, and examples of such resins include, but are not limited to, water-soluble resins, water-dispersible resins, and solvent-soluble resins.

[0077] Examples of the binder resins include, but are not limited to, acrylic resins, polyvinyl alcohol resins, starch or derivatives thereof; cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose; water- soluble polymers such as sodium polyacrylate, polyvinylpyrrolidone, acrylamide-acrylic acid ester copolymers, styrene-acrylic copolymers, acrylamide-acrylic acid ester-methacrylic acid ternary copolymers, styrene-maleic anhydride copolymer alkali salts, isobutylene-maleic anhydride copolymer alkali salts, polyacrylamide, sodium alginate, gelatin, and casein; emulsions such as polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylic acid ester, vinyl chloride-vinyl acetate copolymers, polybutyl methacrylate, and ethylene-vinyl acetate copolymers; and latexes such as styrene-butadiene copolymers and styrene-butadiene-acrylic copolymers. Such binder resins may be used alone or in combination of two or more types. Among such binder resins, when transparency is required, acrylic resins, styrene-acrylic copolymers, and the like are preferred as the binder resin.

[0078] - Auxiliary Additives -Examples of the auxiliary additives include, but are not limited to, various types of hindered phenol compounds and hindered amine compounds which have electron accepting properties but relatively little color-developing ability.

[0079] Specific examples of the auxiliary additives include, but are not limited to, 2,2'- methylenebis(4-ethyl-6-tertiary butylphenol), 4,4'-butylidenebis(6-tertiary butyl-2- methylphenol), l,l,3-tris(2-methyl-4-hydroxy-5-tertiary butylphenyl)butane, 1, 1 ,3-tris(2- methyl-4-hydroxy-5-cyclohexylphenyl)butane, 4,4'-thiobis(6-tertiary butyl-2-methylphenol), tetrabromobisphenol A, tetrabromobisphenol S, 4,4-thiobis(2-methylphenol), 4,4'-thiobis(2- chlorophenol), tetrakis(l,2,2,6,6-pentamethyl-4-piperidyl)-l,2,3,4-butane tetracarboxylate, and tetrakis(l,2,2,6,6-tetramethyl-4-piperidyl)-l,2,3,4-butane tetracarboxylate. Such auxiliary additives may be used alone or in combination of two or more types.

[0080] - Heat-Fusible Substances -Examples of the heat-fusible substances include, but are not limited to, fatty acids such as stearic acid and behenic acid; fatty acid amides such as stearic acid amide and palmitic acid amide; fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, and zinc behenate; p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p- benzyloxybenzoate, P-benzyloxynaphthalene, P-phenyl naphthoate, phenyl 1 -hydroxy -2-FN202501297 naphthoate, methyl l-hydroxy-2-naphthoate, diphenyl carbonate, glycol carbonate, dibenzyl terephthalate, dimethyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-di ethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2-diphenoxy ethane, l,2-bis(3-methylphenoxy)ethane, 1,2- bis(4-methylphenoxy)ethane, 1 ,4-diphenoxy-2-butene, 1 ,2-bis(4-methoxyphenylthio)ethane, dibenzoylmethane, 1,4-diphenylthiobutane, l,4-diphenylthio-2-butene, l,3-bis(2- vinyloxy ethoxy )benzene, 1 ,4-bis(2-vinyloxy ethoxy )benzene, p-(2-vinyloxy ethoxy )biphenyl, p-aryloxybiphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyl disulfide, 1,1 -diphenylethanol, 1,1 -diphenylpropanol, p-benzyloxybenzyl alcohol, l,3-phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N- octadecyl carbamoylbenzene, l,2-bis(4-methoxyphenoxy)propane, l,5-bis(4- methoxyphenoxy)-3 -oxapentane, dibenzyl oxalate, bis(4-methylbenzyl) oxalate, and bis(4- chlorobenzyl) oxalate. Such heat-fusible substances may be used alone or in combination of two or more types.

[0081] - Lubricants -Examples of the lubricants include, but are not limited to, higher fatty acids or metal salts thereof, higher fatty acid amides, higher fatty acid esters, animal waxes, vegetable waxes, mineral waxes, and petroleum waxes. Such lubricants may be used alone or in combination of two or more types.

[0082] Examples of the animal waxes include, but are not limited to, a beeswax, lanolin, and spermaceti.

[0083] Examples of the vegetable waxes include, but are not limited to, a candelilla wax, a carnauba wax, a rice wax, a wood wax, and jojoba oil.

[0084] Examples of the mineral waxes include, but are not limited to, ceresin or a derivative thereof.

[0085] Examples of the petroleum waxes include, but are not limited to, paraffin, petrolatum, a microcrystalline wax, and petrolatum.

[0086] An example of synthetic hydrocarbon waxes includes, but is not limited to, Fischer-Tropsch wax.

[0087] Examples of hydrogenated waxes include, but are not limited to, hydrogenated castor oil and derivatives of hydrogenated castor oil.

[0088] - Fillers -Examples of the fillers include, but are not limited to, inorganic fine powders such as calciumFN202501297 carbonate, silica, zinc oxide, titanium oxide, zirconium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated calcium, and surface-treated silica; and organic fine powders such as urea-formaldehyde resins, styrene-methacrylic acid copolymers, polystyrene resins, and vinylidene chloride resins. Such fillers may be used alone or in combination of two or more types.

[0089] The content of the filler in the thermosensitive layer is not particularly limited and can be appropriately selected depending on the purpose, but the content is preferably 0.4 parts by mass or less, and more preferably 0.2 parts by mass or less, per 1 part by mass of the binder resin.

[0090] <Protective Layer>The protective layer is arranged on at least the top surface of the thermosensitive layer. The thermosensitive recording medium according to the present disclosure has an improved scratch resistance against a thermal head due to provision of the thermosensitive layer.

[0091] As used herein, the "top surface" of the thermosensitive layer means a surface of the thermosensitive layer opposite to the surface on which the support is placed.

[0092] As used herein, the protective layer being "arranged on the top surface" of the thermosensitive layer means not only that the protective layer is directly laminated on one surface of the thermosensitive layer, but also that the protective layer may be laminated on one surface of the thermosensitive layer via another layer or member.

[0093] The protective layer being arranged on "at least the top surface" of the thermosensitive layer means that the protective layer may be arranged on a surface other than the top surface of the thermosensitive layer, for example, on a side surface, the top surface of another layer, or the first surface or the second surface of the support. When the protective layer is arranged on the side surface of the thermosensitive layer, the protective layer arranged on the top surface of the thermosensitive layer and the protective layer arranged on the side surface of the thermosensitive layer may be arranged continuously or may not be arranged continuously.

[0094] The protective layer being arranged on "at least the top surface" of the thermosensitive layer means that the protective layer may be arranged so that the area of the protective layer is 100% of the total area of the top surface of the thermosensitive layer (that is, the protective layer may be arranged over the total area of at least the top surface of the thermosensitive layer), or may be arranged so that the area of the protective layer exceeds 100% (that is, the protective layer may be arranged beyond the top surface of the thermosensitive layer). It is noted that it is preferable that the protective layer is not arranged beyond the top surface of theFN202501297 support.

[0095] The shape of the protective layer is thus not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape include, but are not limited to, polygonal shapes such as a square and a rectangle, a circle, an ellipse, a flat plate, and a sheet form.

[0096] For example, when the protective layer is laminated directly on the top surface of the thermosensitive layer and arranged directly on the side surface of the thermosensitive layer, the protective layer on the top surface of the thermosensitive layer and the protective layer on the side surface of the thermosensitive layer may be arranged continuously. When the protective layer is laminated on the top surface of the thermosensitive layer via another layer or member and is arranged directly on the side surface of the thermosensitive layer, the protective layer on the top surface of the thermosensitive layer and the protective layer on the side surface of the thermosensitive layer may not be arranged continuously.

[0097] The composition of the protective layer is not particularly limited and can be appropriately selected from compositions used as protective layers for known thermosensitive recording media. The protective layer preferably contains a binder resin and a pigment (filler), and more preferably further contains a crosslinking agent, a wax, or the like, and may further contain other components as necessary. When the protective layer contains a pigment, the abrasion resistance of the thermosensitive layer and the matching with a thermal head can be improved, and the heat resistance can also be improved.

[0098] «Binder Resins»The binder resins are not particularly limited and can be appropriately selected depending on the purpose. Examples of the binder resins include, but are not limited to, thermoplastic resins, thermosetting resins, and photocurable resins. The properties of such resins are not particularly limited, and examples of such resins include, but are not limited to, water-soluble resins, water-dispersible resins, and solvent-soluble resins.

[0099] The binder resins contained in the protective layer can be those similar to the binder resins described in the section titled as "- Binder Resins -" under "«Other Components»" in the above section titled as "<Thermosensitive Layer>".

[0100] The content of the binder resins in the protective layer is not particularly limited as long as the effects of the present disclosure are not impaired, and can be appropriately selected depending on the purpose.

[0101] FN202501297«Pigments»The pigment (filler) is not particularly limited and can be appropriately selected depending on the purpose. The pigment (filler) may be an inorganic filler or an organic filler.

[0102] Examples of the inorganic filler include, but are not limited to, carbonates, silicates, metal oxides, and sulfate compounds.

[0103] Specific examples of the inorganic filler include, but are not limited to, zinc oxide, calcium carbonate, barium sulfate, titanium oxide, lithopone, talc, rosewood, kaolin, aluminum hydroxide, and calcined kaolin.

[0104] Examples of the organic filler include, but are not limited to, silicone resins, cellulose, epoxy resins, nylon resins, phenol resins, polyurethane resins, urea resins, melamine resins, polyester resins, polycarbonate resins, styrene resins, acrylic resins, polyethylene resins, formaldehyde resins, polymethyl methacrylate resins, crosslinked polystyrene resins, urea resins, crosslinked polymethyl methacrylate resins, and melamine-formaldehyde resins.

[0105] Such pigments (fillers) may be used alone or in combination of two or more types.

[0106] The content of the pigment in the protective layer is not particularly limited as long as the effects of the present disclosure are not impaired, and can be appropriately selected depending on the purpose. However, the content is preferably 5 parts by mass or more and 200 parts by mass or less, and more preferably 10 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0107] «Crosslinking Agent»The crosslinking agent is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the crosslinking agent allows for reduction of the solubility of the water-soluble resin in water by reacting with the water-soluble resin.

[0108] Specific examples of the crosslinking agent include, but are not limited to, glyoxal derivatives, methylol derivatives, epichlorohydrin, polyamide epichlorohydrin, epoxy compounds, aziridine compounds, hydrazine, hydrazide derivatives, oxazoline derivatives, and carbodiimide derivatives. Such crosslinking agents may be used alone or in combination of two or more types. Among such crosslinking agents, polyamide epichlorohydrin is preferred as the crosslinking agent because the polyamide epichlorohydrin is highly safe to be handled and the curing time required to impart water resistance is short.

[0109] The content of the crosslinking agent in the protective layer is not particularly limited as longFN202501297 as the effects of the present disclosure are not impaired, and can be appropriately selected depending on the purpose. However, the content is preferably 10 parts by mass or more and 60 parts by mass or less, and more preferably 20 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0110] «Wax»It is preferable for the protective layer to contain a wax in terms of improving the slipperiness with respect to the thermal head.

[0111] Examples of waxes include animal waxes, vegetable waxes, mineral waxes, petroleum waxes, polyethylene oxide waxes, montan waxes, zinc stearate, and silicone waxes. Such waxes may be used alone or in combination of two or more types. Among such waxes, oxidized polyethylene wax is preferred.

[0112] Examples of the animal waxes include, but are not limited to, a beeswax, lanolin, and spermaceti.

[0113] Examples of the vegetable waxes include, but are not limited to, a candelilla wax, a carnauba wax, a rice wax, a wood wax, and jojoba oil.

[0114] Examples of the mineral waxes include, but are not limited to, ceresin or a derivative thereof.

[0115] Examples of the petroleum waxes include, but are not limited to, paraffin, petrolatum, a microcrystalline wax, and petrolatum.

[0116] An example of synthetic hydrocarbon waxes includes, but is not limited to, Fischer-Tropsch wax.

[0117] Examples of hydrogenated waxes include, but are not limited to, hydrogenated castor oil and derivatives of hydrogenated castor oil.

[0118] Examples of the oxidized polyethylene wax include, but are not limited to, a polyethylene wax oxidized by air oxidation and / or ozone oxidation (introducing a carboxyl group, a hydroxyl group and / or a formyl group).

[0119] The weight average molecular weight of the oxidized polyethylene wax is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 500 or more and 10,000 or less, more preferably 600 or more and 9,000 or less, and particularly preferably 700 or more and 8,000 or less. The weight average molecular weight of theFN202501297 oxidized polyethylene wax can be measured using a static light scattering photometer (for example, the product name: SLS-6000, static light scattering photometer, manufactured by Otsuka Electronics Co., Ltd.) at a measurement temperature of 160°C by using 1- chloronaphthalene as a solvent.

[0120] Examples of commercially available oxidized polyethylene waxes include, but are not limited to, the product name: RP-960 (manufactured by Chukyo Yushi Co., Ltd., solid content: 30%) and the product name: L-787 (manufactured by Chukyo Yushi Co., Ltd., solid content: 30%).

[0121] The volume average particle size of the wax is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.3 pm or more and 6 pm or less. The volume average particle size of the wax can be measured using a laser diffraction / scattering type particle size distribution measuring device (for example, trade name: LA-960, manufactured by Horiba, Ltd.).

[0122] The content of the wax in the protective layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 100 parts by mass or less, and more preferably 25 parts by mass or less, per 100 parts by mass of the binder resin.

[0123] The wax in the protective layer may be optionally used in combination with other known lubricants. In the protective layer, examples of other lubricants that can be combined with the wax include the waxes described in the lubricants as other components in the thermosensitive layer.

[0124] «Other Components»The other components in the protective layer are not particularly limited as long as the effects of the present disclosure are not impaired and can be appropriately selected depending on the purpose. Examples of the other components include, but are not limited to, auxiliary additive components such as a surfactant, a heat-fusible substance, a lubricant, and an agent for preventing color development due to pressure. Components similar to the other components in the thermosensitive layer may be used.

[0125] The contents of the other components in the protective layer are not particularly limited as long as the effects of the present disclosure are not impaired, and can be appropriately selected depending on the purpose.

[0126] The average thickness of the protective layer is not particularly limited and can be selected at random as necessary, but is preferably 0.5 pm or more and 5 pm or less, and more preferably 1 pm or more and 3 pm or less.FN202501297

[0127] As used herein, the "average thickness" of the protective layer means an average value calculated from the thicknesses at 20 points selected at random from the protective layer, after measuring the thicknesses at such 20 points. The thickness of the protective layer can be measured by using a cross-sectional sample preparation device (for example, a cross-section polisher SM-09020CP, manufactured by JEOL Ltd.) to cut the thermosensitive recording medium in the thickness direction (lamination direction) to expose the cross-section surface, and then observing the cross-section surface with a scanning electron microscope (SEM) (for example, S-3700, manufactured by Hitachi High-Tech Corporation).

[0128] <Cleaning layer>The cleaning layer is arranged in a partial region of the first surface of the support, where the partial region is different from the region in which the thermosensitive layer is arranged. In a cross-sectional view obtained by cutting the thermosensitive recording medium in the first direction at a predetermined position in the second direction, the thermosensitive layer and the cleaning layer are arranged in different regions. The first direction is preferably coincident with the transport direction of the thermal printer. When the first direction is coincident with the transport direction of the thermal printer, the cleaning layer is partially arranged in the transport direction of the thermal printer to be aligned with the thermosensitive layer.

[0129] The thermosensitive recording medium according to the present disclosure includes a cleaning layer, and thus, minute amounts of the material adhering to the support due to plate fogging of an ink material, a thermosensitive layer material, or a protective layer material can be prevented from accumulating as head residue upon contact with the thermal head to reduce printing defects.

[0130] The predetermined position in the second direction means a position selected at random from the second direction of the thermosensitive recording medium. The thermosensitive recording medium can be cut by any means, such as a cutter, scissors, a razor blade, a cutting machine, or a laser. The arrangement of the thermosensitive layer and the cleaning layer can be confirmed by any means including observing the cross section of the thermosensitive recording medium using any means such as a laser microscope, an optical microscope, a scanning electron microscope, or measuring the cross section using a scale. The thermosensitive layer and the cleaning layer can be identified as well as the arrangement of the thermosensitive layer and the cleaning layer can be confirmed by using means such as color development due to heat or fluorescent X-ray measurement.

[0131] The shape of the cleaning layer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape include, but are not limited to, polygonalFN202501297 shapes such as a square and a rectangle, a circle, an ellipse, a flat plate, and a sheet form. Among such shapes, the shape is preferably a rectangle having a long side in the second direction because the cleaning layer can contact with a wide area in the width direction of the thermal printer and can clean the thermal head over a wide area.

[0132] The dimensions of the cleaning layer on the first surface of the support are not particularly limited and can be selected appropriately depending on the purpose, but it is preferable that the minimum length Xc of the cleaning layer in the first direction, the minimum length Xp of the protective layer in the first direction, and the maximum length Xs of the support in the first direction satisfy the following relationship: (Xc + Xp) / Xs > 0.25. This can further significantly prevent adhesion of head residue.

[0133] Furthermore, there are no particular limitations on the minimum length Xc of the cleaning layer in the first direction and the maximum length Xs of the support in the first direction, but it is preferable to satisfy Xc / Xs > 0.05. This further improves the effect of preventing printing defects caused by head residue.

[0134] It is noted that when there are a plurality of regions in the first direction in which a cleaning layer is arranged in a thermosensitive recording medium, the minimum length Xc of the cleaning layer in the first direction means the minimum total length of the plurality of cleaning layers in the first direction. The total length of the cleaning layers can be determined from the total length of the plurality of cleaning layers on a cross-sectional line in the first direction when the thermosensitive recording medium is cut in the first direction at a predetermined position in the second direction.

[0135] It is noted that when there are a plurality of regions in the first direction in which a protective layer is arranged in a thermosensitive recording medium, the minimum length Xp of the cleaning layer in the first direction means the minimum total length of the plurality of cleaning layers in the first direction. The total length of the protective layers can be determined from the total length of the plurality of protective layers on a cross-sectional line in the first direction when the thermosensitive recording medium is cut in the first direction at a predetermined position in the second direction.

[0136] There are no particular limitations on the maximum length Yc of the cleaning layer in the second direction and the maximum length Ys of the support in the second direction, but it is preferable to satisfy Yc = Ys. This can further significantly prevent adhesion of head residue.

[0137] It is noted that when there are a plurality of regions in the second direction in which a cleaning layer is arranged in a thermosensitive recording medium, the maximum length Yc ofFN202501297 the cleaning layer in the second direction means the maximum total length of the plurality of cleaning layers in the second direction. The total length of the cleaning layers can be determined from the total length of the cleaning layers on a cross-sectional line in the second direction when the thermosensitive recording medium is cut toward the second direction at a predetermined position in the first direction.

[0138] The haze in the region where the support and the cleaning layer are laminated is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less. The haze in the region where the support and the cleaning layer are laminated may be measured using a haze meter (for example, device name: HZ-V3, manufactured by Suga Test Instruments Co., Ltd.).

[0139] The composition of the cleaning layer is not particularly limited and can be appropriately selected depending on the purpose, but the cleaning layer preferably contains a binder resin and a pigment (filler), and more preferably further contains a crosslinking agent, and a wax, and may further optionally contain other components. The cleaning layer containing a pigment can suitably prevent head residue from adhering to the thermal head.

[0140] For the materials of the cleaning layer, such as a binder resin, a pigment, a crosslinking agent, and a wax, those described in the section <Protective Layer> can be suitably employed. The same applies to the other components in the cleaning layer.

[0141] A composition of the material of the cleaning layer and a composition of the material of the protective layer may be the same or different. Among these, it is preferable that the cleaning layer and the protective layer have the same composition. This allows the cleaning layer and the protective layer to be provided simultaneously within one unit of a gravure printing machine to improve productivity.

[0142] The cleaning layer and the protective layer may be arranged separately in different regions, or may be arranged continuously.

[0143] The composition of material and the arrangements of the cleaning layer and the protective layer may be combined. Examples thereof include that the material composition of the cleaning layer and the material composition of the protective layer are the same, and the cleaning layer and the protective layer are arranged separately in different regions; that the material composition of the cleaning layer and the material composition of the protective layer are the same, and the cleaning layer and the protective layer are arranged continuously; that the material composition of the cleaning layer and the material composition of theFN202501297 protective layer are the same, the cleaning layer and the protective layer are arranged in different layers, and the cleaning layer and the protective layer are arranged separately in different regions (that is, the cleaning layer and the protective layer are laminated via another layer or member); that the material composition of the cleaning layer and the material composition of the protective layer are the same, the cleaning layer and the protective layer are arranged in different layers, and the cleaning layer and the protective layer are arranged continuously; that the cleaning layer and the protective layer have different material compositions, the cleaning layer and the protective layer are arranged in different layers, and the cleaning layer and the protective layer are arranged separately in different regions (that is, the cleaning layer and the protective layer are laminated via another layer or member); and that the cleaning layer and the protective layer have different material compositions, the cleaning layer and the protective layer are arranged in different layers, and the cleaning layer and the protective layer are arranged continuously.

[0144] It is noted that when the composition of the material of the cleaning layer and the composition of the material of the protective layer are different, the boundary between the cleaning layer and the protective layer can be distinguished even if the cleaning layer and the protective layer are arranged continuously. On the other hand, in the thermosensitive recording medium according to the present disclosure, when the composition of the material of the cleaning layer and the composition of the material of the protective layer are the same and the cleaning layer and the protective layer are arranged continuously, the boundary therebetween cannot be distinguished. The cleaning layer is arranged in at least a partial region of at least the top surface of the support or another layer such as the color ink layer, and the protective layer is arranged on at least the top surface of the thermosensitive layer, however, when the composition of the material of the cleaning layer and the composition of the material of the protective layer are the same and the cleaning layer and the protective layer are arranged continuously, the cleaning layer and the protective layer are not distinguished and may function as a "protective part" together.

[0145] When the composition of the material of the protective layer and the composition of the material of the cleaning layer are different, the boundary therebetween may be confirmed, for example, by each analyzing the composition of the materials, such as the shape and element types of the pigments (fillers) in the protective layer and the cleaning layer by using a scanning electron microscope energy dispersive X-ray spectroscopy (SEM-EDX).

[0146] When the composition of the material of the protective layer and the composition of the material of the cleaning layer are different, for example, the cleaning layer can have the composition containing at least a binder resin, a crosslinking agent, a pigment (filler), and a wax, and the protective layer can also have the composition containing at least a binder resin,FN202501297 a crosslinking agent, a pigment (filler), and a wax.

[0147] When the composition of the material of the protective layer and the composition of the material of the cleaning layer are the same, for example, the protective layer and the cleaning layer may both have the composition containing at least a binder resin and a crosslinking agent, or both may have the composition containing at least a binder resin, a crosslinking agent, a pigment (filler), and a wax.

[0148] A shape, a structure, a dimension, the number, and arrangement of the cleaning layer are not particularly limited and can be appropriately selected depending on the purpose. The shape of the cleaning layer is preferably in the form of a layer.

[0149] The average thickness of the cleaning layer is not particularly limited and can be selected at random as necessary, but is preferably 0.5 pm or more and 5 pm or less, and more preferably 1 pm or more and 3 pm or less.

[0150] As used herein, the "average thickness" of the cleaning layer means an average value calculated from the thicknesses at 20 points selected at random from the cleaning layer, after measuring the thicknesses at such 20 points. The thickness of the cleaning layer can be measured by cutting the thermosensitive recording medium in the thickness direction (lamination direction) using a cross-sectional sample preparation device (for example, Cross- Section Polisher SM-09020CP, manufactured by JEOL Ltd.) to expose the cross-section surface, and then observing the cross-section surface with a scanning electron microscope (SEM) (for example, S-3700, manufactured by Hitachi High-Tech Corporation).

[0151] <Other Members>Other members in the thermosensitive recording medium according to the first embodiment of the present disclosure are not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include, but are not limited to, a back layer, an under layer, a heat seal layer, a release layer, and an adhesive layer.

[0152] «Back Layer»When the thermosensitive recording medium includes a back layer, curling of the thermosensitive recording medium can be suppressed. On the other hand, when the thermosensitive recording medium has transparency, it is preferable not to arrange the back layer.

[0153] When the back layer is arranged in the thermosensitive recording medium, the back layer is preferably arranged on the surface of the support opposite to the surface on which theFN202501297 thermosensitive layer is arranged, that is, on the bottom surface of the support.

[0154] The back layer is not particularly limited and can be appropriately selected depending on the purpose, but contains a binder resin and a pigment (filler), and may further optionally contain other components such as a lubricant and a coloring pigment. The binder resin and the lubricant used may be similar to those in the thermosensitive layer. The pigment (filler) similar to that in the protective layer may be employed for the pigment (filler). The coloring pigment is not particularly limited and can be appropriately selected from known pigments.

[0155] The average thickness of the back layer is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 0.1 pm or more and 20 pm or less, and more preferably 0.3 pm or more and 10 pm or less.

[0156] «Under Layer»The under layer can improve the color development sensitivity of the thermosensitive recording medium. On the other hand, if the thermosensitive recording medium requires transparency, it is preferable not to arrange the under layer.

[0157] When the under layer is arranged in the thermosensitive recording medium, the under layer is preferably arranged between the support and the thermosensitive layer.

[0158] When the under layer is arranged, the under layer is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the under layer contains an adhesive resin, thermoplastic hollow resin particles, and the like, and further optionally contains other components.

[0159] The thermoplastic hollow resin particles are minute hollow particles including a thermoplastic resin as a shell and containing air or other gases inside, and are already in a foamed state.

[0160] The average particle size (outer particle diameter) of the thermoplastic hollow resin particles is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.2 pm or more and 20 pm or less, and more preferably 2 pm or more and 5 pm or less. When the average particle size of the thermoplastic hollow resin particles is 0.2 pm or more, it is technically easy to produce hollow particles, and the undercoat layer can function satisfactorily. On the other hand, if the average particle size is 20 pm or less, the smoothness of the surface after applying and drying is not reduced, and the application of the thermosensitive layer is less likely to become uneven, making it unnecessary to apply more than the amount of thermosensitive layer forming liquid necessary to achieve uniformity. Therefore, it is desirable that the average particle size of the thermoplastic hollow resinFN202501297 particles is within the above range, and at the same time, the particle size distribution has a uniform peak with little variation.

[0161] The hollow ratio of the thermoplastic hollow resin particles is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 30% or more and 95% or less, more preferably 50% or more and 95% or less, and even more preferably 80% or more and 95% or less. When the hollow rate of the thermoplastic hollow resin particles is 30% or more, the heat insulating properties are sufficient, and the thermal energy from the thermal head is not released to the outside of the thermosensitive recording medium through the support, so that the sensitivity improving effect can be sufficiently obtained.

[0162] As used herein, the hollow ratio of the thermoplastic hollow resin particles is based on the ratio of the outer diameter of the thermoplastic hollow resin particles to the inner diameter (diameter of the hollow portion) of the thermoplastic hollow resin particles and is represented by the following formula 1.[Formula 1]Hollow ratio (%) of thermoplastic hollow resin particle = (Inner diameter of thermoplastic hollow resin parti cle / Outer diameter of thermoplastic hollow resin particle) x 100

[0163] It is noted that as described above, the thermoplastic hollow resin particles have a shell formed of a thermoplastic resin, and the thermoplastic resin is not particularly limited and can be appropriately selected depending on the purpose. Examples of the thermoplastic resin include, but are not limited to, styrene-acrylic resins, polystyrene resins, acrylic resins, polyethylene resins, polypropylene resins, polyacetal resins, chlorinated polyether resins, polyvinyl chloride resins, and copolymer resins mainly formed of vinylidene chloride and acrylonitrile. Among such thermoplastic resins, styrene-acrylic resins and copolymer resins mainly formed of vinylidene chloride and acrylonitrile are preferable for the thermoplastic resin, because of a high hollow ratio, a small variation in particle size, and suitability for blade coating.

[0164] «Heat Seal Layer»The heat seal layer is formed by laminating films formed of LDPE (low density polyethylene) used as a sealant, and therefore, the heat seal layer can be welded by heating heat seal layers in a state of being in close contact with each other. Taking advantage of such a property, a packaging sheet formed into a bag shape can be sealed, that is, heat-sealed, by heating the packaging sheet under the same conditions.Therefore, any material that allows heat sealing, that is, has heat sealability, can be used to form the heat seal layer, without being limited to LDPE.

[0165] FN202501297When the heat seal layer is arranged on the thermosensitive recording medium, the heat seal layer is preferably arranged on the side of the support opposite to the side on which the thermosensitive layer is arranged, that is, the bottom surface of the support; when arranged on the side of the support on which the thermosensitive layer is arranged, the heat seal layer is preferably arranged, for example, between the support and the thermosensitive layer or the color ink layer. The heat seal layer may be arranged on one or both sides of the thermosensitive layer, among them.

[0166] Examples of suitably used substances having heat sealability include, but are not limited to, films formed of high density polyethylene (HDPE), cast polypropylene (CPP), oriented polypropylene (OPP), an ethylene-vinyl acetate copolymer (EVA) or the like, and other examples may include polyolefin resins such as polyethylene and polypropylene; vinyl acetate-based resins such as ethylene- vinyl acetate copolymers (olefin-vinyl acetate copolymers, and the like); acrylic resins such as ethylene-(meth)acrylic acid copolymers and ionomer [olefm-(meth)acrylic acid copolymers, metal cross-linked products thereof, or the like]. Also, the heat seal layer may be formed by using a well-known heat sealable adhesive. It is noted that it is preferable to use a member that becomes transparent after forming the heat seal layer to see a packaged item.

[0167] The average thickness of the heat seal layer is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of the transparency and the seal strength, the average thickness is preferably 5 pm or more and 50 pm or less, and more preferably 10 pm or more and 30 pm or less.

[0168] «Release Layer»The release layer may be provided to protect the thermosensitive recording medium from scratches and the like. The release layer is released when the thermosensitive recording medium is used.

[0169] When the release layer is provided on the thermosensitive recording medium, the release layer is preferably provided on the top surface of the protective layer and / or the protective layer.

[0170] The release layer contains a release agent. The release agent is not particularly limited and can be appropriately selected depending on the purpose. Examples of the release agent include, but are not limited to, ultraviolet curing silicone, heat curing silicone, solventless silicone, solvent type silicone, emulsion type silicone, and fluorine-based release agents.

[0171] «Adhesive Layer»When the thermosensitive recording medium is used adhesively, the adhesive layer may beFN202501297 arranged. The adhesive layer is preferably arranged on the surface of the support opposite to the surface on which the thermosensitive layer is arranged, that is, on the bottom surface of the support. When the thermosensitive recording medium includes the back layer, it is preferable to place the adhesive layer on the bottom surface of the back layer, that is, on the surface of the back layer opposite to the surface in contact with the support.

[0172] The main component of the adhesive contained in the adhesive layer is preferably at least one selected from an acrylic resin obtained by emulsion polymerization of a monomer mainly formed of at least one kind of (meth)acrylic acid alkyl ester having an alkyl group, an acrylic acid ester-styrene copolymer, and an acrylic acid ester-methacrylic acid ester-styrene copolymer.

[0173] Here, the "main component" of the adhesive means a component formed only of a resin, excluding additives such as penetrating agents, film-forming assistants, defoamers, rust inhibitors, thickeners, wetting agents, preservatives, UV absorbers, light stabilizers, pigments, and inorganic fillers that are optionally blended into the adhesive. As used herein, "(meth)acrylic" means "acrylic or methacrylic".

[0174] Specific examples of (meth)acrylic acid alkyl esters include, but are not limited to, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, and n-dodecyl (meth)acrylate. Such (meth)acrylic acid alkyl esters may be used alone or in combination of two or more types.

[0175] As used herein, the "average thickness" of each layer serving as the other members means an average value calculated from the thicknesses of each layer at 20 points selected at random from each layer, after measuring the thicknesses at such 20 points. The thickness of each layer can be measured by observing the cross-section surface with an SEM in the same manner as in measuring the thickness of the thermosensitive layer.

[0176] Next, examples of a layout mode of each layer in the thermosensitive recording medium according to the first embodiment of the present disclosure will be described in detail with reference to the drawings. In FIG. lAto FIG. 4B, a Z-axis direction indicates a lamination direction of a thermosensitive recording medium 100, that is, a thickness direction of the thermosensitive recording medium 100. An X-axis direction and a Y-axis direction are perpendicular to the Z-axis direction. The X-axis direction indicates a first direction of the thermosensitive recording medium, and the Y-axis direction indicates a second direction of the thermosensitive recording medium. The X-axis direction is perpendicular to the Y-axis direction.

[0177] FN202501297It is noted that it is preferable that the thermosensitive recording medium according to the first embodiment of the present disclosure is long in the first direction, and that one layout is laid out as repeated patterns in the first direction. In FIG. lAto FIG. 4B, only one of such repeated patterns is illustrated and described.

[0178] It is preferable that the support is continuous between one pattern and the other pattern following the one pattern, but the cleaning layer, the protective layer, and the like may be arranged between the two patterns.

[0179] [Layout Mode Example 1]FIG. 1 A is a schematic top view of an example of a first surface 1 A of a thermosensitive recording medium according to the first embodiment of the present disclosure. FIG. IB is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IB-IB in FIG. 1 A. FIG. 5 is a diagram illustrating a relationship in size among the support 1, a protective layer 3, and a cleaning layer 4 in FIG. 1 A.

[0180] The thermosensitive recording medium 100 having a first direction Fd and a second direction Sd perpendicular to the first direction Fd includes the support 1 including a second surface IB facing the first surface 1 A, a thermosensitive layer 2 arranged in a partial region of the first surface 1 A of the support 1, the protective layer 3 arranged on at least the top surface of the thermosensitive layer 2, and the cleaning layer 4 arranged in a partial region of the first surface 1 A of the support 1, which is different from the region in which the thermosensitive layer 2 is arranged. The first surface 1 A of the support 1 has at least an exposed part at least partially exposed from the thermosensitive layer 2, the cleaning layer 4, and the protective layer 3, and, in a cross-sectional view obtained by cutting the thermosensitive recording medium 100 in the first direction Fd at a predetermined position in the second direction Sd, the thermosensitive layer 2 and the cleaning layer 4 are arranged in different regions. In a top view, the thermosensitive layer 2 is arranged below the protective layer 3, and therefore an outer edge 2a of the thermosensitive layer 2 and an outer edge 3 a of the protective layer 3 coincide with each other.

[0181] In a layout mode example 1, in a cross-sectional view obtained by cutting the thermosensitive recording medium 100 in the first direction Fd at a predetermined position in the second direction Sd, the cleaning layer 4 and the thermosensitive layer 2 are arranged in different regions, and one side surface of the cleaning layer 4 (the side surface on the thermosensitive layer 2 side) is in contact with one side surface of the thermosensitive layer 2 (the side surface on the cleaning layer side). In a cross-sectional view cut in the second direction Sd, the length of the thermosensitive layer 2 and the length of the cleaning layer 4 are the same. It is noted that the exposed part refers to a region on the first surface 1 A of the support 1 where theFN202501297 thermosensitive layer 2, the protective layer 3, and the cleaning layer 4 are not arranged.

[0182] Here, as illustrated in FIG. 5, there are no particular limitations on a minimum length Xc of the cleaning layer 4 in the first direction Fd, a minimum length Xp of the protective layer 3 in the first direction Fd, and a maximum length Xs of the support 1 in the first direction Fd, but it is preferable to satisfy (Xc + Xp) / Xs > 0.25. This can further significantly prevent adhesion of head residue.

[0183] There are no particular limitations on the minimum length Xc of the cleaning layer 4 in the first direction Fd and the maximum length Xs of the support 1 in the first direction Fd, but it is preferable to satisfy Xc / Xs > 0.05. This can further significantly prevent adhesion of head residue.

[0184] [Layout Mode Example 2]FIG. 2A is a schematic top view of another example of the first surface 1 A of the thermosensitive recording medium according to the first embodiment of the present disclosure. FIG. 2B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IIB-IIB in FIG. 2A.

[0185] A layout mode example 2 differs from the layout mode example 1 in that the protective layer 3 is arranged not only on the top surface of the thermosensitive layer 2 but also on the side surfaces thereof. Therefore, in a top view, the outer edge 2a of the thermosensitive layer 2 is located inside the outer edge 3a of the protective layer 3.

[0186] [Layout Mode Example 3]FIG. 3 A is a schematic top view of another example of the first surface 1 A of the thermosensitive recording medium according to the first embodiment of the present disclosure. FIG. 3B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IIIB-IIIB in FIG. 3 A. FIG. 6 is a diagram illustrating a relationship in size among the support 1, the protective layer 3, and the cleaning layer 4 in FIG. 3 A.

[0187] A layout mode example 3 differs from the layout mode example 1 in that one side surface of the cleaning layer 4 (the side surface on the thermosensitive layer 2 side) is not in contact with one side surface of the thermosensitive layer 2 (the side surface on the cleaning layer 4 side), and the support 1 is arranged to be exposed between the thermosensitive layer 2 and the protective layer 3, and the cleaning layer 4.

[0188] Here, as illustrated in FIG. 6, there are no particular limitations on the minimum length Xc ofFN202501297 the cleaning layer 4 in the first direction Fd, the minimum length Xp of the protective layer 3 in the first direction Fd, and the maximum length Xs of the support 1 in the first direction Fd, but it is preferable to satisfy (Xc + Xp) / Xs > 0.25. This can further significantly prevent adhesion of head residue.

[0189] There are no particular limitations on the minimum length Xc of the cleaning layer 4 in the first direction Fd and the maximum length Xs of the support 1 in the first direction Fd, but it is preferable to satisfy Xc / Xs > 0.05. This can further significantly prevent adhesion of head residue.

[0190] [Layout Mode Example 4]FIG. 4A is a schematic top view of another example of the first surface 1 A of the thermosensitive recording medium according to the first embodiment of the present disclosure. FIG. 4B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IVB-IVB in FIG. 4A.

[0191] A layout mode example 4 differs from the layout mode example 2 in that one side surface of the cleaning layer 4 (the side surface on the thermosensitive layer 2 side) is not in contact with one side surface of the thermosensitive layer 2 (the side surface on the cleaning layer side), and the support 1 is arranged to be exposed between the thermosensitive layer 2 and the protective layer 3, and the cleaning layer 4.

[0192] [Second Embodiment]A thermosensitive recording medium according to a second embodiment of the present disclosure differs from the thermosensitive recording layer according to the first embodiment in that, in addition to the support, the thermosensitive layer, the protective layer, and the cleaning layer, a color ink layer is further provided on the second surface of the support.

[0193] The thermosensitive recording medium according to the second embodiment includes the color ink layer on the second surface of the support, that is, the color ink layer on the surface opposite, across the support, to the thermosensitive layer, and the like arranged on the first surface of the support. Thus, the design of the thermosensitive recording medium can be improved and plate fogging of the color ink layer can be suppressed on the first surface of the support on which the thermosensitive layer is arranged.

[0194] The differences of the thermosensitive recording medium according to the second embodiment from that according to the first embodiment will be described below.

[0195] <Color Ink Layer>FN202501297The color ink layer is a layer having printed color ink and having various colors, materials, and thicknesses. The color ink layer can impart design to the image recorded on the thermosensitive recording medium according to the present disclosure, and can form the background of the image printed on the thermosensitive layer. Therefore, in using the thermosensitive recording medium for packaging printing, provision of the color ink layer makes it possible to write a product name, a manufacturer name, an ingredient list, and the like, before the product is packaged, and also possible to give the product excellent design. The thermosensitive recording medium according to the present disclosure is not limited to use for packaging, and the color ink layer may be printed with information such as characters, marks, pictures, bar codes, or two-dimensional codes such as QRcode®.

[0196] A shape, a structure, a dimension, the number, and arrangement of the color ink layer are not particularly limited, and the color ink layer is preferably arranged in a partial region on the second surface of the support.

[0197] The color ink layer contains a coloring material and a binder resin, and further optionally contains other components. The binder resin and the other components may be similar to those in the thermosensitive layer.

[0198] «Coloring Material»The coloring material is not particularly limited and can be appropriately selected depending on the purpose, and known pigments or dyes can be used.

[0199] The content of the coloring material in the color ink layer is not particularly limited as long as the effects of the present disclosure are not impaired, and can be appropriately selected depending on the purpose.

[0200] The average thickness of the color ink layer is not particularly limited and can be selected appropriately optionally, but is preferably 0.05 pm or more and 4 pm or less, and more preferably 0.1 pm or more and 2 pm or less.

[0201] As used herein, the "average thickness" of the color ink layer means an average value calculated from the thicknesses at 20 points selected at random from the color ink layer, after measuring the thicknesses at such 20 points. The thickness of the color ink layer can be measured by cutting the thermosensitive recording medium in the thickness direction (lamination direction) using a cross-sectional sample preparation device (for example, Cross- Section Polisher SM-09020CP, manufactured by JEOL Ltd.) to expose the cross-section surface, and then observing the cross-section surface with a scanning electron microscope (SEM) (for example, S-3700, manufactured by Hitachi High-Tech Corporation).FN202501297

[0202] Next, a layout mode example of each layer in the thermosensitive recording medium according to the second embodiment of the present disclosure will be described in detail with reference to the drawings. In FIG. 7Ato FIG. 11B, a Z-axis direction indicates the lamination direction of the thermosensitive recording medium 100, that is, the thickness direction of the thermosensitive recording medium 100. An X-axis direction and a Y-axis direction are perpendicular to the Z-axis direction. The X-axis direction indicates a first direction of the thermosensitive recording medium, and the Y-axis matter indicates a second direction of the thermosensitive recording medium. The X-axis direction is perpendicular to the Y-axis direction.

[0203] It is noted that it is preferable that the thermosensitive recording medium according to the second embodiment of the present disclosure is long in the first direction, similarly to the thermosensitive recording medium according to the first embodiment, and that one layout is laid out as repeated patterns in the first direction. In FIG. 7Ato FIG. 11B, only one of such repeated patterns is illustrated and described.

[0204] [Layout Mode Example 5]FIG. 7A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the second embodiment of the present disclosure. FIG. 7B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line VIIB-VIIB in FIG. 7A.

[0205] A layout mode example 5 differs from the layout mode example 3 in that the color ink layer 5 is arranged on the second surface IB of the support. The color ink layer 5 is arranged on the second surface IB of the support 1 at a position facing the thermosensitive layer 2 and at a position facing the exposed part of the support.

[0206] [Layout Mode Example 6]FIG. 8A is a schematic top view of another example of the first surface 1 A of the thermosensitive recording medium according to the second embodiment of the present disclosure. FIG. 8B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line VIIIB-VIIIB in FIG. 8A.

[0207] A layout mode example 6 differs from the layout mode example 5 in that the color ink layer 5 extends from a position facing the thermosensitive layer 2 to a position corresponding to the cleaning layer 4 on the second surface IB of the support 1.

[0208] [Layout Mode Example 7]FN202501297FIG. 9A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the second embodiment of the present disclosure. FIG. 9B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line IXB-IXB in FIG. 9A.

[0209] A layout mode example 7 differs from the layout mode example 4 in that the color ink layer 5 is arranged on the second surface IB of the support. The color ink layer 5 extends from a position facing the thermosensitive layer 2 to a position corresponding to the cleaning layer 4 on the second surface IB of the support 1.

[0210] [Layout Mode Example 8]FIG. 10A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the second embodiment of the present disclosure. FIG. 10B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XB-XB in FIG. 10 A.

[0211] A layout mode example 8 differs from the layout mode example 1 in that the color ink layer 5 is arranged on the second surface IB of the support. The color ink layer 5 is arranged at a position facing the thermosensitive layer 2, a position corresponding to the cleaning layer 4, and a position facing the exposed part of the support 1 around the thermosensitive layer 2 and the cleaning layer 4, on the second surface IB of the support 1. Therefore, the outer edge 5a of the color ink layer 5 is outside the outer edge 2a of the thermosensitive layer 2 and the outer edge 4a of the cleaning layer 4.

[0212] [Layout Mode Example 9]FIG. 11 A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the second embodiment of the present disclosure. FIG. 11B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIB-XIB in FIG. 11 A.

[0213] A layout mode example 9 differs from the layout mode example 2 in that the color ink layer 5 is arranged on the second surface IB of the support. The color ink layer 5 is arranged at a position facing the protective layer 3, a position corresponding to the cleaning layer 4, and a position facing the exposed part of the support 1 around the protective layer 3 and the cleaning layer 4, on the second surface IB of the support 1. Therefore, the outer edge 5a of the color ink layer 5 is outside the outer edge 3a of the protective layer 3 and the outer edge 4a of the cleaning layer 4.

[0214] [Third Embodiment]FN202501297The thermosensitive recording medium according to the third embodiment of the present disclosure differs from the thermosensitive recording layer according to the first embodiment in that, in addition to the support, the thermosensitive layer, the protective layer, and the cleaning layer, a color ink layer is further provided on the first surface of the support.

[0215] In the thermosensitive recording medium according to the third embodiment of the present disclosure, the color ink layer is arranged in at least one manner selected from: (1) at least the top surface of the color ink layer is exposed; (2) the thermosensitive layer is arranged on at least the top surface of the color ink layer; and (3) the cleaning layer is arranged on at least the top surface of the color ink layer.

[0216] The thermosensitive recording medium according to the third embodiment includes the color ink layer on the first surface of the support, that is, includes the thermosensitive layer and the like arranged on the first surface of the support and the color ink layer on the same surface of the support. Thus, the design of the thermosensitive recording medium can be improved.

[0217] The differences of the thermosensitive recording medium according to the third embodiment from that according to the second embodiment will be described, below.

[0218] As used herein, the "top surface" of the color ink layer means a surface of the color ink layer opposite to the surface on which the support is placed.

[0219] The thermosensitive recording medium according to the third embodiment of the present disclosure may include the color ink layer on the first surface of the support, and at least one of the cleaning layer and the protective layer may be arranged over at least the entire top surface of the color ink layer. This makes it possible to improve a scratch resistance of the color ink layer against the thermal head, and also possible to prevent a printing defect caused by deposition of ink residue on the thermal head due to scratching the color ink layer.

[0220] As used herein, at least one of the cleaning layer and the protective layer being "arranged on the top surface" of the color ink layer means not only that at least one of the cleaning layer and the protective layer is directly laminated on one surface of the thermosensitive layer, but also that at least one of the cleaning layer and the protective layer may be laminated on one surface of the color ink layer via another layer or member.

[0221] At least one of the cleaning layer and the protective layer being "arranged at least on the top surface" of the color ink layer means that at least one of the cleaning layer and the protective layer may be arranged on a surface other than the top surface of the color ink layer, for example, on a side surface. When at least one of the cleaning layer and the protective layer isFN202501297 arranged on the side surface of the color ink layer, at least one of the cleaning layer and the protective layer arranged on the top surface of the color ink layer and at least one of the cleaning layer and the protective layer arranged on the side surface of the color ink layer may be arranged continuously or may not arranged continuously.

[0222] At least one of the cleaning layer and the protective layer being arranged on "at least the top surface" of the color ink layer means that at least one of the cleaning layer and the protective layer may be arranged so that the area of at least one of the cleaning layer and the protective layer is 100% over the entire area of the top surface of the color ink layer (that is, at least one of the cleaning layer and the protective layer may be arranged over the entire surface of at least the top surface of the color ink layer), or may be arranged so that such an area exceeds 100% (that is, at least one of the cleaning layer and the protective layer may be arranged beyond the top surface of the color ink layer). It is noted that it is preferable that at least one of the cleaning layer and the protective layer is not arranged beyond the top surface of the support.

[0223] For example, when at least one of the cleaning layer and the protective layer is laminated directly on the top surface of the color ink layer and arranged directly on the side surface of the color ink layer, at least one of the cleaning layer and the protective layer on the top surface of the color ink layer and at least one of the cleaning layer and the protective layer on the side surface of the color ink layer may be arranged continuously. When at least one of the cleaning layer and the protective layer is laminated on the top surface of the color ink layer via another layer or member and is arranged directly on the side surface of the color ink layer, at least one of the cleaning layer and the protective layer on the top surface of the color ink layer and at least one of the cleaning layer and the protective layer on the side surface of the color ink layer may not be arranged continuously.

[0224] As described in the second embodiment, the color ink layer is often placed on the side of the support opposite to the side of the thermosensitive layer, but depending on the configuration of the thermosensitive layer, the color ink layer may also be placed on the same side as the recording layer on the first top surface of the support. In particular, when the color ink layer is arranged on the first side of the support, the color ink layer is preferably arranged between the support and the cleaning layer, between the support and the protective layer, and between the support and the thermosensitive layer, for example.

[0225] In the thermosensitive recording medium according to the third embodiment of the present disclosure, partial printing can be performed by arranging the color ink layer in a partial region of the first surface of the support. This makes it possible to form the color ink layer simultaneously with the thermosensitive layer. In the thermosensitive recording mediumFN202501297 according to the third embodiment of the present disclosure, in a case where the color ink layer is arranged in a partial region of the first surface of the support, when contents are packaged in the thermosensitive recording medium serving as a packaging sheet, the contents can be easily viewed from the region where the color ink layer is not arranged.

[0226] Next, a layout mode example of each layer in the thermosensitive recording medium according to the third embodiment of the present disclosure will be described in detail with reference to the drawings. In FIG. 12Ato FIG. 19B, a Z-axis direction indicates the lamination direction of the thermosensitive recording medium 100, that is, the thickness direction of the thermosensitive recording medium 100. An X-axis direction and a Y-axis direction are perpendicular to the Z-axis direction. The X-axis direction indicates a first direction of the thermosensitive recording medium, and the Y-axis direction indicates a second direction of the thermosensitive recording medium. The X-axis direction is perpendicular to the Y-axis direction.

[0227] It is noted that it is preferable that the thermosensitive recording medium according to the third embodiment of the present disclosure is long in the first direction, similarly to the thermosensitive recording medium according to the first embodiment, and that one layout is laid out as repeated patterns in the first direction. In FIG. 12Ato FIG. 19B, only one of such repeated patterns is illustrated and described.

[0228] [Layout Mode Example 10]FIG. 12A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the third embodiment of the present disclosure. FIG. 12B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIIB-XIIB in FIG. 12 A.

[0229] A layout mode example 10 differs from the layout mode example 3 in that the color ink layer 5 is arranged between the support 1 and the thermosensitive layer 2. That is, in the layout mode example 10, the thermosensitive layer 2 is arranged at least on the top surface of the color ink layer 5. The color ink layer 5 is larger in dimension than the thermosensitive layer 2 in the first direction Fd and the second direction Sd on the first surface 1A of the support 1.

[0230] [Layout Mode Example 11]FIG. 13 A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the third embodiment of the present disclosure. FIG. 13B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIIIB-XIIIB in FIG. 13 A.

[0231] FN202501297A layout mode example 11 differs from the layout mode example 10 in that on the top surface of the color ink layer 5, the protective layer 3 is arranged in a region where the thermosensitive layer 2 is not arranged. That is, in the layout mode example 11, the thermosensitive layer 2 and the protective layer 3 are arranged at least on the top surface of the color ink layer.

[0232] [Layout Mode Example 12]FIG. 14A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the third embodiment of the present disclosure. FIG. 14B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIVB-XIVB in FIG. 14A.

[0233] In a layout mode example 12, the cleaning layer 4 is arranged in a partial region of the first surface 1 A of the support 1, the color ink layer 5, the thermosensitive layer 2, and the protective layer 3 are laminated in another partial region in this order, and the color ink layer 5 is arranged in yet another partial region of the support 1. In the layout mode example 12, at least the top surface of one of the color ink layers 5 is exposed. On at least the top surface of the other color ink layer 5, the thermosensitive layer 2 is arranged.

[0234] [Layout Mode Example 13]FIG. 15A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the third embodiment of the present disclosure. FIG. 15B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XVB-XVB in FIG. 15 A.

[0235] A layout mode example 13 differs from the layout mode example 12 in that the color ink layer 5 is also arranged between the support 1 and the cleaning layer 4. Therefore, in the layout mode example 13, at least the top surface of one of the color ink layers 5 is exposed. On at least the top surface of the other color ink layer 5, the cleaning layer 4 is arranged.

[0236] [Layout Mode Example 14]FIG. 16A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the third embodiment of the present disclosure. FIG. 16B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XVIB-XVIB in FIG. 16A.

[0237] A layout mode example 14 differs from the layout mode example 13 in that the color ink layer 5 is also arranged between the support 1 and the thermosensitive layer 2. Therefore, in the layout mode example 13, at least the top surface of one of the color ink layers 5 is exposed.FN202501297On at least the top surface of the other color ink layer 5, the cleaning layer 4 is arranged. On at least the top surface of yet another color ink layer 5, the thermosensitive layer 2 is arranged.

[0238] [Layout Mode Example 15]FIG. 17A is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium according to the third embodiment of the present disclosure. FIG. 17B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XVIIB-XVIIB in FIG. 17A.

[0239] A layout mode example 15 differs from the layout mode example 1 in that the color ink layer 5 is arranged between the support 1 and the cleaning layer 4 and between the support 1 and the thermosensitive layer 2. In the layout mode example 15, over the entire surface of at least the top surface of the color ink layer 5, the cleaning layer 4 and the protective layer 3 are arranged.

[0240] Next, a more preferred embodiment of the cleaning layer 4 will be described.

[0241] [Layout Mode Example 16]FIG. 18A is a schematic top view of an example of the first side 1 A of the thermal recording medium of the present disclosure. FIG. 18B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XVIIIB- XVIIIB in FIG. 18 A.

[0242] A layout mode example 16 differs from the layout mode example 3 in that a length Yc of the cleaning layer 4 in the second direction Sd matches a length Ys of the support 1 in the second direction Sd, that is, the relationship of Yc = Ys is satisfied. This allows the cleaning layer 4 to come into contact with a wide area in the width direction of the head of the thermal printer, making it possible to further reduce printing defects caused by adhesion of head residue.

[0243] [Layout Mode Example 17]FIG. 19A is a schematic top view of an example of the first side 1 A of the thermosensitive recording medium of the present disclosure. FIG. 19B is a schematic cross-sectional view of the thermosensitive recording medium in the thickness direction, taken along line XIXB- XIXB in FIG. 19 A.

[0244] A layout mode example 17 differs from the layout mode example 1 in that the length Yc of the cleaning layer 4 in the second direction Sd matches the length Ys of the support 1 in the second direction Sd, the length Xc of the cleaning layer 4 in the first direction Fd is approximately the same as the length Xs of the thermosensitive layer 2 in the first directionFN202501297Fd, and the area of the cleaning layer 4 relative to the support 1 is large. That is, in the layout example 17, the relationships of Yc = Ys, (Xc + Xp) / Xs > 0.25, and (Xc + Xp) / Xs > 0.25 are satisfied. This allows the cleaning layer 4 to come into contact with a wide area in both the width direction and the transport direction of the head of the thermal printer, making it possible to further reduce printing defects caused by adhesion of head residue.

[0245] [Layout Mode Example 18]FIG. 22 is a schematic top view of an example of the first surface 1 A of the thermosensitive recording medium of the present disclosure. FIG. 22 illustrates a plurality of patterns being continuously arranged in the first direction Fd. The thermosensitive recording medium of the present disclosure can be formed into various forms such as a label form, a sheet form, a roll form, or the like, but in a case where the plurality of patterns long in the first direction Fd are included, the roll form is preferable.

[0246] <Applications>The applications of the thermosensitive recording medium according to the present disclosure are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include, but are not limited to, labels used in the Point of Sales (POS) field or the like to be affixed to fresh food, boxed lunches, side dishes, or the like; and bands to be wrapped around fresh food, boxed lunches, side dishes, or the like. Through the use in the above applications, the visibility of the contents is improved, and a consumer can select a product while checking the contents. Examples of other applications include tickets, tags, and cards. More specifically, examples include ticket vending machines, and a field of issuing receipts, vouchers, and the like; packaging tags in the aircraft industry, pill cases, and pill bottles; and output paper for facsimile machines in a field of copying books and documents.

[0247] A method for manufacturing the thermosensitive recording medium is not particularly limited and can be appropriately selected from well-known methods, but the method for manufacturing the thermosensitive recording medium according to the present disclosure described below can be suitably used.

[0248] (Method of Manufacturing Thermosensitive Recording Medium)A method for manufacturing the thermosensitive recording medium according to the present disclosure includes forming a thermosensitive layer, forming a cleaning layer, and forming a protective layer. It is preferable that the method for manufacturing a thermosensitive recording medium according to the present disclosure further includes forming a color ink layer where appropriate, and may further include other processing where appropriate.

[0249] The method for manufacturing a thermosensitive recording medium according to the presentFN202501297 disclosure can suitably manufacture the thermosensitive recording medium according to the present disclosure.

[0250] <Forming Thermosensitive Layer>In forming a thermosensitive layer, a thermosensitive layer forming liquid is applied to a partial region of the first surface of the support to form the thermosensitive layer.

[0251] As used herein, applying the thermosensitive layer forming liquid "to the first surface" of the support means not only that the thermosensitive layer forming liquid is applied directly to the first surface of the support, but also that the thermosensitive layer forming liquid may be applied to the first surface of the support via another layer or member. For example, the thermosensitive layer forming liquid may be applied to the top surface of the color ink layer arranged on the support.

[0252] As used herein, applying the thermosensitive layer forming liquid to "a partial region" of the first surface of the support means applying the thermosensitive layer forming liquid so that the area to which the thermosensitive layer forming liquid is applied is less than 100% of the total area of the first surface of the support.

[0253] The method for forming the thermosensitive layer is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a method for forming the thermosensitive layer by applying the thermosensitive layer forming liquid onto the support and drying the liquid.

[0254] The method for applying the thermosensitive layer forming liquid to a partial region of the first surface of the support is not particularly limited, and the layer can be formed by using a generally known printing method. In the method for manufacturing a thermosensitive recording medium according to the present disclosure, the thermosensitive layer and the cleaning layer are formed in a partial region of the first surface of the support, and thus, the thermosensitive layer and the cleaning layer can be formed simultaneously.

[0255] The printing method is not particularly limited, and any well-known printing method can be used. Among such well-known printing methods, a gravure printing method and a flexographic printing method are preferred. Generally, such printing methods are often used on paper or film substrates for packaging, and because a plurality of colors are required for printing, devices including print heads for 5 to 12 colors in one process are commonly used. Therefore, for example, a print head can be used to print several colors of color ink for design printing, and the remaining print heads can be used to print the thermosensitive layer forming liquid, and further a cleaning layer forming liquid in one pass at the same time, and thus,FN202501297 better design position accuracy can be provided rather than production using two or more passes, and also productivity is significantly improved.

[0256] Such studies can be carried out more efficiently by combining laboratory-scale, pilot-scale, and actual equipment-scale studies. In the laboratory-scale study, for example, evaluation can be provided using a lab printing machine (PRINTABILITY TESTER manufactured by IGT, FLEXIPROOF manufactured by Matsuo Sangyo Co., Ltd.) or the like, but the evaluation machine is not limited to such a machine, and evaluation can be provided using any commonly available lab printing machine. In the pilot-scale study and the actual equipmentscale study, more practical evaluation can be provided by preparing various gravure rolls and flexographic plates according to the design and the deposition amount required for evaluation.

[0257] The deposition amount of the thermosensitive layer forming liquid after drying is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 g / m2or more and 20 g / m2or less, and more preferably 2 g / m2or more and 10 g / m2or less.

[0258] «Thermosensitive Layer Forming Liquid»The thermosensitive layer forming liquid contains an electron-donating compound, an electron-accepting compound, and a solvent, preferably further contains a surfactant and a binder resin, and may further optionally contain other components.

[0259] The electron-donating compound, the electron-accepting compound, the binder resin, and other components are as described above in the section titled as <Thermosensitive Layer> of (Thermosensitive Recording Medium).

[0260] - Solvent -The solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples of the solvent include, but are not limited to, water, aromatic solvents, ester solvents, ketone solvents, alcohol solvents, aliphatic hydrocarbons, glycol solvents, paraffin solvents, petroleum-based solvents containing naphthene as the main component and having an aromatic component of 1% or less, and mixed solvents thereof. Such solvents may be used alone or in combination of two or more types. Among such solvents, from the viewpoints of the solubility of the electron-accepting compound and reduction of the environmental load, the solvent is suitably an alcohol solvent, an ester solvent, or a mixed solvent of water and an alcohol solvent. Aromatic solvents such as toluene have low solubility for electron-accepting compounds, but the use of such a solvent is restricted from the viewpoint of reducing the environmental load due to VOC emissions in the printing industry.FN202501297

[0261] Examples of the alcohol solvent include, but are not limited to, methanol, ethanol, isopropyl alcohol, n-propyl alcohol, and butanol. Among such alcohol solvents, ethanol is particularly preferred.

[0262] Examples of the ester solvent include, but are not limited to, ethyl acetate, propyl acetate, isopropyl acetate, isobutyl acetate, butyl acetate, isoamyl acetate, amyl acetate, hexyl acetate, phenyl acetate, and benzyl acetate.

[0263] Examples of water include, but are not limited to, pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, and ultrapure water.

[0264] The content of the solvent in the thermosensitive layer forming liquid is not particularly limited and can be appropriately selected depending on the purpose.

[0265] - Surfactant -When the thermosensitive layer forming liquid contains a surfactant, the surface tension of the thermosensitive layer forming liquid can be adjusted, and the desired shape and structure can be obtained more precisely when the thermosensitive layer forming liquid is applied to a partial region of the first surface of the support.

[0266] The surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the surfactant include, but are not limited to, anionic surfactants, nonionic surfactants, amphoteric surfactants, and fluorine-based surfactants.

[0267] Examples of the anionic surfactants include, but are not limited to, polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, and polyoxyethylene alkyl ether sulfates. Such anionic surfactants may be used alone or in combination of two or more types.

[0268] Examples of the nonionic surfactants include, but are not limited to, acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, and polyoxyethylene sorbitan fatty acid esters. Such nonionic surfactants may be used alone or in combination of two or more types.

[0269] Examples of the acetylene glycol surfactants include, but are not limited to, 2, 4,7,9- tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-l-hexyne-3-diol, and 2,5,8,ll-tetramethyl-6-dodecyne-5,8-diol. Such acetylene glycol surfactants may be used alone or in combination of two or more types.

[0270] FN202501297The content of the surfactant in the thermosensitive layer forming liquid is not particularly limited and can be appropriately selected depending on the purpose.

[0271] The method for preparing the thermosensitive layer forming liquid is not particularly limited, and any well-known method can be used. An example of the method includes a method including pulverizing and dispersing an electron-donating compound, an electron-accepting compound, and a solvent, optionally together with other components in a dispersing machine such as a ball mill, an attritor, or a sand mill until the desired dispersed particle size is reached.

[0272] The dispersed particle size of the thermosensitive layer forming liquid is not particularly limited, but is preferably 0.1 pm or more and 3 pm or less.

[0273] <Forming Protective Layer>In forming the protective layer, a protective layer forming liquid is applied to at least the top surface of the thermosensitive layer to form the protective layer.

[0274] The forming the protective layer is performed after the forming the thermosensitive layer.

[0275] As used herein, the "applying the protective layer forming liquid to the top surface" of the thermosensitive layer means not only that the protective layer forming liquid is applied directly to one surface of the thermosensitive layer, but also that the protective layer forming liquid may be applied to one surface of the thermosensitive layer via another layer or member. For example, when an intermediate layer is formed on at least the top surface of the thermosensitive layer, the protective layer forming liquid may be applied to at least a partial region of the top surface of the intermediate layer. In such a case, the protective layer is formed in at least a partial region of at least the top surface of the intermediate layer, the region facing at least a part of the thermosensitive layer.

[0276] The applying the protective layer forming liquid to "at least the top surface" of the thermosensitive layer means that the protective layer forming liquid may be applied to a surface other than the top surface of the thermosensitive layer, for example, a side surface. When the protective layer forming liquid is applied to the side surface of the thermosensitive layer, the protective layer forming liquid applied to the top surface of the thermosensitive layer and the protective layer forming liquid applied to the side surface of the thermosensitive layer may be applied simultaneously or separately. When the protective layer on the top surface of the thermosensitive layer and the protective layer on the side surface of the thermosensitive layer are formed to be continuous, it is efficient to simultaneously apply the protective layer forming liquid to the top surface of the thermosensitive layer and theFN202501297 protective layer forming liquid to the side surface of the thermosensitive layer.

[0277] As used herein, the applying the protective layer forming liquid to "at least the top surface" of the thermosensitive layer means that the protective layer forming liquid may be applied so that the area to which the protective layer forming liquid is applied is 100% of the total area of the top surface of the thermosensitive layer (that is, the protective layer forming liquid is applied to the entire surface of at least the top surface of the thermosensitive layer), or that the protective layer forming liquid may be applied so that the area to which the protective layer forming liquid is applied is more than 100% of the total area of the top surface of the thermosensitive layer (that is, the protective layer forming liquid is applied beyond the top surface of the thermosensitive layer). However, it is preferable that the protective layer forming liquid is not applied beyond the first surface of the support.

[0278] The method for forming the protective layer is not particularly limited and can be appropriately selected depending on the purpose. An example of the method may include a method for forming the protective layer by applying the protective layer forming liquid onto the support and drying the protective layer forming liquid.

[0279] The method for applying the protective layer forming liquid to at least the top surface of the thermosensitive layer is not particularly limited, and a method similar to the method for applying the thermosensitive layer forming liquid to a partial region of the top surface of the support can be used.

[0280] The deposition amount of the protective layer forming liquid after drying the protective layer forming liquid is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 g / m2or more and 10 g / m2or less, and more preferably 0.5 g / m2or more and 3.0 g / m2or less.If the deposition amount is too small, the sufficient head matching effect cannot be obtained, and if the deposition amount is too large, a heat transfer during printing by the printer decreases, which may result in a decrease in print quality and density.

[0281] <Forming Cleaning Layer>In forming a cleaning layer, a cleaning layer forming liquid is applied to at least a partial region of the first surface of the support to form the cleaning layer.

[0282] As used herein, applying the cleaning layer forming liquid "to the first surface" of the support means not only that the cleaning layer forming liquid is applied directly to the first surface of the support, but also that the cleaning layer forming liquid may be applied to the first surface of the support via another layer or member.FN202501297For example, the cleaning layer forming liquid may be applied to the top surface of the color ink layer arranged on the support.

[0283] As used herein, applying the cleaning layer forming liquid to "a partial region" of the first surface of the support means applying the cleaning layer forming liquid so that the area to which the cleaning layer forming liquid is applied is less than 100% of the total area of the first surface of the support.

[0284] The method for forming the cleaning layer is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a method for forming the cleaning layer by applying the cleaning layer forming liquid onto the support and drying the liquid.

[0285] The method for applying the cleaning layer forming liquid to a partial region of the first surface of the support is not particularly limited, and the layer can be formed by using a generally known printing method. In the method for manufacturing a thermosensitive recording medium according to the present disclosure, the thermosensitive layer and the cleaning layer are formed in a partial region of the first surface of the support, and thus, the thermosensitive layer and the cleaning layer can be formed simultaneously.

[0286] The printing method is not particularly limited, and any well-known printing method can be used. Among such well-known printing methods, a gravure printing method and a flexographic printing method are preferred. The printing method may be similar to printing the thermosensitive layer.

[0287] The deposition amount of the cleaning layer forming liquid after drying the cleaning layer forming liquid is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 g / m2or more and 10 g / m2or less, and more preferably 0.5 g / m2or more and 3.0 g / m2or less.

[0288] «Cleaning Layer Forming Liquid and Protective Layer Forming Liquid»The composition of the cleaning layer forming liquid and the composition of the protective layer forming liquid may be the same or different. The cleaning layer forming liquid and the protective layer forming liquid contain a binder resin and a solvent, and preferably further contain a crosslinking agent, a pigment (filler), a wax, and the like, and may further contain other components where appropriate.

[0289] The cleaning layer forming liquid preferably contains at least a binder resin, a solvent, and a pigment (filler), and more preferably further contains a crosslinking agent and a wax.FN202501297

[0290] The protective layer forming liquid preferably contains a binder resin, a solvent, a crosslinking agent, a pigment (filler), and a wax.

[0291] The binder resin, the crosslinking agent, and the other components are as described above in the section titled as <Cleaning Layer> or <Protective Layer> of (Thermosensitive Recording Medium). The solvent may be similar to that used in the thermosensitive layer forming liquid.

[0292] The method for preparing the cleaning layer forming liquid and the protective layer forming liquid is not particularly limited, and any well-known method can be used. An example of the method may include a method in which a binder resin, a solvent, and further other components, where appropriate, are mixed.

[0293] When at least one of the cleaning layer forming liquid and the protective layer forming liquid contains a wax, it is preferable to use a dispersion obtained by wet dispersion using a dispersant to disperse the wax.

[0294] The dispersion is not particularly limited and can be appropriately selected depending on the purpose. Examples of the dispersion include, but are not limited to, (i) an aqueous dispersion in which a wax, preferably an oxidized polyethylene wax, is dispersed in water using polyvinyl alcohol serving as a dispersant, and (ii) an emulsion in which a wax, preferably an oxidized polyethylene wax, is emulsified and dispersed using an anionic emulsifier.

[0295] <Forming Color Ink Layer>In forming the color ink layer, the color ink is applied to a partial region of the first surface or the second surface or both of such faces of the support to form the color ink layer. There are no particular limitations on the order in forming the color ink layer and forming the thermosensitive layer.

[0296] As used herein, applying the color ink to the support means not only that the color ink is applied directly to one surface of the support, but also that the color ink may be applied to one surface of the support via another layer or member.

[0297] As used herein, applying the color ink to a "partial region" of the top surface of the support means applying the color ink so that the area to which the color ink is applied is less than 100% of the total area of the first surface of the support.

[0298] The method for forming the color ink layer is not particularly limited and may beFN202501297 appropriately selected depending on the purpose. An example of the method includes a method for forming the color ink layer by applying the color ink onto the support and drying such an applied layer.

[0299] The method for applying color ink to a partial region of one surface or the both surfaces of the support is not particularly limited, and the method similar to the method for applying the thermosensitive layer forming liquid to a partial region of the first surface of the support can be employed.

[0300] The deposition amount of color ink after drying is not particularly limited and can be appropriately selected depending on the purpose, but the average thickness of the color ink layer is preferably 0.05 g / m2or more and 10 g / m2or less, and more preferably 0.5 g / m2or more and 4.0 g / m2or less.

[0301] «Color Ink»The color ink contains a coloring material and a solvent, and preferably further contains a surfactant and a binder resin, and may further optionally contain other components.

[0302] The coloring material, the binder resin, and other components are as described above in the section titled as <Color Ink Layer> of (Thermosensitive Recording Medium). The solvent and the surfactant may be similar to those used in the thermosensitive layer forming liquid.

[0303] The color ink may be appropriately prepared by a well-known method, or commercially available products may be used.

[0304] <Other Processes>Other processes in the method for manufacturing a thermosensitive recording medium according to the present disclosure are not particularly limited, and an example of the other processes includes, but is not limited to, a process for forming other layers in the thermosensitive recording medium, such as a back layer, an under layer, a heat seal layer, a release layer, and an adhesive layer.

[0305] The method for forming such other layers is not particularly limited, and an example of the method includes a method in which a layer forming liquid in which the constituent materials of each layer are mixed is applied and laminated in much the same manner as the method for applying the thermosensitive layer forming liquid, the color ink, and the like.

[0306] (Image Recording Method)An image recording method according to the present disclosure includes recording an imageFN202501297 on the thermosensitive recording medium according to the present disclosure using the thermal head. It is preferable that the transport direction of the thermal head is coincident with the first direction of the thermosensitive recording medium.As a result, it is possible to further reduce the printing defects caused by adhesion of head residue.[Examples]

[0307] The present disclosure will be specifically described below with reference to Preparation Examples, Examples, and Comparative Examples, but the present disclosure is not limited to such Preparation Examples, Examples, and Comparative Examples at all.

[0308] (Preparation Example 1)Preparation of Thermosensitive Layer Forming Liquid>6.2 parts by mass of a black dye (ODB2, manufactured by Yamamoto Chemicals Co., Ltd.) as an electron-donating compound, 18.7 parts by mass of N,N'-di-[3-(p- toluenesulfonyloxy)phenyl]urea represented by the following structural formula (1) as an electron-accepting compound, 40.0 parts by mass of an acrylic resin (A-1125, manufactured by DSM, 19.5% by mass water solvent solution of solid content), 4.6 parts by mass of a styrene-acrylic resin (JONCRYL PDX-7741, manufactured by BASF, 41.5% by mass water solvent solution of solid content), 1.9 parts by mass of a surfactant (PD-001, manufactured by Nisshin Chemical Industry Co., Ltd., 10% by mass of solid content), 15 parts by mass of water, and 13.6 parts by mass of ethanol were dispersed using a sand mill to prepare the thermosensitive layer forming liquid.[Chem. 1]

[0309] (Preparation Example 2)Preparation of Pigment Dispersion>84.2 parts by mass of calcium carbonate as a pigment, 20.2 parts by mass of a styrene-acrylic resin (JONCRYL PDX-7741, manufactured by BASF, 41.5% by mass water solvent solution of solid content), 0.4 parts by mass of a surfactant (PD-001, manufactured by Nisshin Chemical Industry Co., Ltd., 10% by mass of solid content), 51.1 parts by mass of water, and 51.1 parts by mass of ethanol were dispersed using a sand mill such that the 50% cumulative volume particle size (D50) measured by a laser diffraction / scattering type particle size distribution measuring device (device name: LA-960, manufactured by Horiba, Ltd.) is 0.2FN202501297 m to obtain a pigment dispersion liquid (45% by mass of solid content, ethanol mass ratio in solvent: 44.8% by mass).

[0310] (Preparation Example 3)Preparation of Protective Layer Forming Liquid>20.7 parts by mass of the pigment dispersion liquid prepared in Preparation Example 2, 47.7 parts by mass of an acrylic resin (A-1125, manufactured by DSM, 19.5% by mass water solvent solution of solid content), 9.5 parts by mass of an oxazoline derivative (EPOCROS (registered trademark) WS-500, manufactured by Nippon Shokubai Co., Ltd., solid content concentration: 39% by mass) serving as a crosslinking agent, 4.7 parts by mass of an oxidized polyethylene wax (30% by mass water solvent solution of solid content), 5 parts by mass of water, and 40 parts by mass of ethanol were mixed and stirred to prepare the protective layer forming liquid.

[0311] (Preparation Example 4)Preparation of Cleaning Layer Forming Liquid 1>20.7 parts by mass of the pigment dispersion liquid prepared in Preparation Example 2, 47.7 parts by mass of an acrylic resin (A-1125, manufactured by DSM, 19.5% by mass water solvent solution of solid content), and 31.4 parts by mass of ethanol were mixed and stirred to prepare the cleaning layer forming liquid.(Preparation Example 5)Preparation of Cleaning Layer Forming Liquid 2>20.7 parts by mass of the pigment dispersion liquid prepared in Preparation Example 2, 47.7 parts by mass of an acrylic resin (A-1125, manufactured by DSM, 19.5% by mass water solvent solution of solid content), 9.5 parts by mass of an oxazoline derivative (EPOCROS (registered trademark) WS-500, manufactured by Nippon Shokubai Co., Ltd., solid content concentration: 39% by mass) serving as a crosslinking agent, 4.7 parts by mass of an oxidized polyethylene wax (30% by mass water solvent solution of solid content), 5 parts by mass of water, and 31.4 parts by mass of ethanol were mixed and stirred to prepare the cleaning layer forming liquid.

[0312] (Printing Method)In the following Examples 1 to 9 and the Comparative Example 1, the thermosensitive layer 2, the protective layer 3, the cleaning layer 4, and the color ink layer 5 were all printed by the following gravure printing method.

[0313] -Preparing Doctor Blade-Assuming the latter half of the actual manufacturing production of the thermosensitive recording medium 100, a cylinder was set in a small gravure printing test machineFN202501297 manufactured by Chiba Kikai Kogyo Co., Ltd. After introducing the thermosensitive layer forming liquid, the protective layer forming liquid, and the cleaning layer forming liquid, the machine was operated for two hours at a line speed of 40 m / min with the doctor blade applied.

[0314] -Gravure Printing-A gravure roll with an outer diameter of 200 mmcp was set on a compact gravure printing test machine manufactured by Chiba Kikai Kogyo Co., Ltd. Using a doctor blade that had been prepared after two hours of operation, gravure printing was performed under the conditions of a line speed of 40 m / min and a drying set temperature of 70°C, according to each layout illustrated in Examples 1 to 9 and Comparative Example 1, followed by drying.

[0315] (Example 1)Preparation of Thermosensitive Recording Medium>In Example 1, the thermosensitive recording medium 100 illustrated in FIG. 1 A and FIG. IB was prepared by the following method.

[0316] «Formation of Thermosensitive Layer 2»A polyethylene terephthalate (PET) film (product name: E5102, average thickness: 12 pm, manufactured by Toyobo Co., Ltd., haze: 2.3%) with a length of 20 cm in the second direction was used as the support 1. Using the above gravure printing method, the thermosensitive layer forming liquid obtained in Preparation Example 1 was printed onto a partial region at the center portion of the first surface 1 A of the PET film, so that the deposition amount after drying was 4 g / m2After drying, the thermosensitive layer 2 was formed, as illustrated in FIG. 1 A and FIG. IB, having a rectangular shape in a top view, with a length Xh of 25 cm in the first direction and a length of 10 cm in the second direction.

[0317] «Formation of Protective Layer 3»The protective layer forming liquid obtained in Preparation Example 3 was printed by the gravure printing method described above over the entire top surface of the thermosensitive layer 2 such that the deposition amount after drying was 2 g / m2. After drying, the protective layer 3 was formed as illustrated in FIG. 1 A and FIG. IB. That is, the protective layer 3 having a length of 25 cm in the first direction and a length of 10 cm in the second direction was formed on the top surface of the thermosensitive layer 2.

[0318] «Formation of Cleaning Layer 4»The cleaning layer forming liquid 1 obtained in Preparation Example 4 was printed by the gravure printing method described above on a partial region of a central portion of the first surface 1 A of the support 1, and the partial region was different from the region of theFN202501297 thermosensitive layer 2, such that the deposition amount after drying was 2 g / m2. After drying, the cleaning layer 4 was formed as illustrated in FIG. 1 A and FIG. IB, which had a rectangular shape in a top view, with a length of 5 cm in the first direction and a length of 10 cm in the second direction. It is noted that the cleaning layer 4 was arranged to be aligned with the thermosensitive layer 2 along the first direction, and was arranged such that one side surface of the cleaning layer 4 (side surface on the thermosensitive layer 2 side) was in contact with one side surface of the thermosensitive layer 2 (side surface on the cleaning layer side). The length of the thermosensitive layer 2 in the second direction and the length of the cleaning layer 4 are the same.

[0319] (Example 2)In Example 2, the thermosensitive recording medium 100 illustrated in FIG. 3 A and FIG. 3B was prepared by the following method.Specifically, the thermosensitive recording medium 100 was prepared in much the same manner as in Example 1, except that in forming the cleaning layer 4 of Example 1, the cleaning layer 4 was arranged to be aligned with the thermosensitive layer 2 along the first direction, and was arranged with a gap so that one side surface of the cleaning layer 4 (side surface on the thermosensitive layer 2 side) was not in contact with one side surface of the thermosensitive layer 2 (side surface on the cleaning layer side).

[0320] (Example 3)In Example 3, the thermosensitive recording medium 100 was prepared in much the same manner as in Example 1, except that the formation of the thermosensitive layer 2 and the formation of the protective layer 3 in forming the thermosensitive layer 2 as in Example 1 were changed as follows.

[0321] «Formation of Thermosensitive Layer 2»In the formation of the thermosensitive layer 2 of Example 1, the thermosensitive layer 2 was formed in much the same manner as in Example 1, except that the thermosensitive layer forming liquid was gravure printed on the first surface 1 A of the support 1 such that the length in the first direction was 28 cm.

[0322] «Formation of Protective Layer 3»In the formation of the protective layer 3 of Example 1, the protective layer 3 was formed in much the same manner as in Example 1, except that the protective layer forming liquid was gravure printed on the top surface of the thermosensitive layer 2 such that the length in the first direction was 28 cm.

[0323] (Example 4)FN202501297In the formation of the thermosensitive layer 2 of Example 1, the thermosensitive recording medium 100 was prepared in much the same manner as in Example 1, except that the formation of the cleaning layer 4 was changed as follows.

[0324] «Formation of Cleaning Layer 4»In the formation of the cleaning layer 4 of Example 1, the cleaning layer 4 was formed in much the same manner as in Example 1, except that the cleaning layer forming liquid 1 was gravure printed on the first surface 1 A of the support 1 such that the length in the first direction was 7 cm.

[0325] (Example 5)Preparation of Thermosensitive Recording Medium>In Example 5, the thermosensitive recording medium 100 illustrated in FIG. 7A and FIG. 7B was prepared. Specifically, in Example 5, the thermosensitive recording medium 100 was prepared in much the same manner as in Example 1, except that in Example 2, the color ink layer 5 was formed on the second surface IB of the support by the following method.

[0326] «Formation of Color Ink Layer 5»A gravure printing ink (product name: FINART R794 White, manufactured by DIC Graphics Corporation) was printed by the gravure printing method described above on a partial region of a central portion of the second surface IB of the polyethylene terephthalate film (product name: E5102) serving as the support 1, which was opposite to the surface on which the thermosensitive layer 2 was formed, such that the deposition amount after drying was 1 g / m2. After drying, the color ink layer 5 was formed as illustrated in FIG. 7A and FIG. 7B, which had a rectangular shape in a top view, with a length of 30 cm in the first direction and a length of 12 cm in the second direction. It is noted that the color ink layer 5 was arranged such that, in a top view, one side surface substantially parallel to the second direction coincided with the side surface of the thermosensitive layer 2 (side surface not adjacent to the cleaning layer 4) facing across the support 1, and the other three sides had outer edges extending outward from the outer edge of the thermosensitive layer 2.

[0327] (Example 6)Preparation of Thermosensitive Recording Medium>In Example 6, the thermosensitive recording medium 100 illustrated in FIG. 12A and FIG. 12B was prepared by the following method.

[0328] «Formation of Color Ink Layer 5»A gravure printing ink (product name: FINART R794 White, manufactured by DIC Graphics Corporation) was printed by the gravure printing method described above on a partial regionFN202501297 of a central portion of the first surface 1 A of a polyethylene terephthalate (PET) film (product name: E5102, average thickness: 12 pm, manufactured by Toyobo Co., Ltd., haze: 2.3%) serving as the support 1 with a length of 20 cm in the second direction, such that the deposition amount after drying was 1 g / m2. After drying, the color ink layer 5 was formed as illustrated in FIG. 12A and FIG. 12B, which had a rectangular shape in a top view, with a length of 28 cm in the first direction and a length of 10 cm in the second direction.

[0329] «Formation of Thermosensitive Layer 2»The thermosensitive layer forming liquid obtained in Preparation Example 1 was printed by the gravure printing method described above on the top surface of the color ink layer 5 such that the deposition amount after drying was 4 g / m2. After drying, the thermosensitive layer 2 was formed as illustrated in FIG. 12A and FIG. 12B, which had a rectangular shape in a top view, with a length of 25 cm in the first direction and a length of 10 cm in the second direction. It is noted that the thermosensitive layer 2 was arranged such that one side surface substantially parallel to the second direction (side surface not adjacent to the cleaning layer 4) and two side surfaces substantially parallel to the first direction coincided with the side surfaces of the color ink layer 5, while the other side surface substantially parallel to the second direction (side surface adjacent to the cleaning layer 4) had an outer edge positioned inward from the outer edge of the color ink layer 5.

[0330] «Formation of Protective Layer 3»The protective layer forming liquid obtained in Preparation Example 3 was printed by the gravure printing method described above over the entire top surface of the thermosensitive layer 2 such that the deposition amount after drying was 2 g / m2. After drying, the protective layer 3 was formed as illustrated in FIG. 12A and FIG. 12B. That is, the protective layer 3 having a length of 25 cm in the first direction and a length of 10 cm in the second direction was formed on the top surface of the thermosensitive layer 2.

[0331] «Formation of Cleaning Layer 4»The cleaning layer forming liquid 1 obtained in Preparation Example 4 was printed by the gravure printing method described above on a partial region of a central portion of the first surface 1 A of the support 1, and the partial region was different from the region of the thermosensitive layer 2, such that the deposition amount after drying was 2 g / m2. After drying, the cleaning layer 4 was formed as illustrated in FIG. 12A and FIG. 12B, which had a rectangular shape in a top view, with a length of 7 cm in the first direction and a length of 10 cm in the second direction. It is noted that the cleaning layer 4 was arranged to be aligned with the thermosensitive layer 2 along the first direction, and was arranged with a gap such that one side surface of the cleaning layer 4 (side surface on the thermosensitive layer 2 side) was not in contact with one side surface of the thermosensitive layer 2 (side surface on theFN202501297 cleaning layer 4 side).

[0332] (Example 7)Preparation of Thermosensitive Recording Medium>In Example 7, the thermosensitive recording medium 100 illustrated in FIG. 13 A and FIG. 13B was prepared by the following method. Specifically, in Example 7, the thermosensitive recording medium 100 was prepared in much the same manner as in Example 7, except that in Example 6, the protective layer 3 was formed by the following method in a region of the top surface of the color ink layer 5 where the thermosensitive layer 2 was not arranged.

[0333] «Formation of Protective Layer 3»The protective layer forming liquid obtained in Preparation Example 3 was printed by the gravure printing method described above on a region of the top surface of the color ink layer 5 where the thermosensitive layer 2 was not arranged, such that the deposition amount after drying was 2 g / m2. After drying, the protective layer 3 was formed as illustrated in FIG. 13 A and FIG. 13B. That is, the protective layer 3 having a length of 3 cm in the first direction and a length of 10 cm in the second direction was formed on the top surface of the color ink layer 5. It is noted that one side surface of the protective layer 3 (side surface opposite to the cleaning layer 4 side), which was arranged to be in contact with the top surface of the color ink layer 5, was arranged to be in contact with one side surface of the thermosensitive layer 2 (side surface on the cleaning layer 4 side). In a top view, the combined outer edge of the protective layer 3, formed by the protective layer 3 arranged to be in contact with the top surface of the thermosensitive layer 2 and the protective layer 3 arranged to be in contact with the top surface of the color ink layer 5, was arranged to coincide with the outer edge of the color ink layer 5.

[0334] (Example 8)Preparation of Thermosensitive Recording Medium>In Example 8, the thermosensitive recording medium 100 illustrated in FIG. 20 A and FIG. 20B was prepared by the following method. Specifically, in Example 8, the thermosensitive recording medium 100 was prepared in much the same manner as in Example 5, except that in Example 5, the cleaning layer 4 was formed as illustrated in FIG. 20A and FIG. 20B, which had a rectangular shape in a top view, with a length of the cleaning layer 4 of 7 cm in the first direction and a length of the cleaning layer 4 of 20 cm in the second direction. The length of the cleaning layer 4 in the second direction was 8 (indicated as "total width" in Table 1), that is, the length was the same as the length of the support 1 in the second direction.

[0335] (Example 9)Preparation of Thermosensitive Recording Medium>FN202501297In the formation of the protective layer 3 of Example 8, the thermosensitive recording medium 100 of Example 9 was produced in much the same manner as in Example 8, except that the cleaning layer forming liquid was changed to the cleaning layer forming liquid 2 obtained in Preparation Example 5.

[0336] (Comparative Example 1)Preparation of Thermosensitive Recording Medium>In Comparative Example 1, the thermosensitive recording medium 100 illustrated in FIG. 21 A and FIG. 2 IB was prepared. Specifically, in Comparative Example 1, the thermosensitive recording medium 100 was prepared in much the same manner as in Example 1.

[0337] [Evaluation]The thermosensitive recording media 100 of Examples 1 to 9 and Comparative Example 1 were printed to develop colors using a thermal printer (model name: DF6530, manufactured by VIDEO JET) at a printing speed of 150 mm / s, printing energy of 100%, and head pressure of 3.5 kg. In the Examples 1 to 4 and the Comparative Example 1, the obtained images were visually inspected by a specialist evaluator for accumulation of ink residue on the thermal head, and unnecessary printing of the thermosensitive layer 2, and were evaluated according to the following evaluation criteria. In the Examples 5 to 9, the obtained images were visually inspected by a specialist evaluator for releasing the color ink layer 5, accumulation of ink residue on the thermal head, and unnecessary printing of the thermosensitive layer 2, and were evaluated according to the following evaluation criteria. The results are presented in Table 1 below. Marks Excellent, Good, and Fair indicate a practical range.

[0338] - Evaluation Criteria for Head Residue Adhesion on Thermal Head -Excellent: No head residue is observed across the entire width of the thermal head after 1,000 m of printingGood: No head residue is observed in the thermal head printing area after 1,000 m of printing, but a small amount of head residue is observed outside the printing areaFair: No head residue is observed across the entire width of the thermal head after 100 m of printing, but head residue is observed across the entire width of the thermal head after 1000 m of printingPoor: Adhesion and accumulation of head residue are observed across the entire width of the thermal head after 100 m of printing

[0339] - Evaluation Criteria for Printing Defects -Excellent: No blurring occurs after 3,000 m of printingGood: No blurring of print occurs after 1,000 m of printing, but blurring of print occurs after over 1,000 m to 3,000 m of continuous printingFN202501297Fair: No blurring of print occurs after 100 m of printing, but blurring of print occurs after over 100 m to 1,000 m of continuous printingPoor: Blurring of print occurs after 100 m of printing

[0340] [Table 1]FN202501297

[0341] In the thermosensitive recording media 100 of Examples 1 to 9 and Comparative Example 1, the layout formed by each layer having repeated patterns in the first direction, and each figure in the Examples and Comparative Examples illustrates only one of such patterns. Therefore, in Table 1, "length Xs of support in first direction", "length Xh of thermosensitive layer in first direction", "length Xp of protective layer in first direction", and "length Xc of cleaning layer in first direction", and "length of color ink layer 5 in first direction" all indicate the length within one pattern of the layout. Further, "length Xs of support in first direction" means "maximum length Xs of the support in first direction", "length Xp of protective layer in first direction" means "minimum length Xp of protective layer in first direction", and "length Xc of cleaning layer in first direction" means "minimum length Xc of cleaning layer in first direction".

[0342] Aspects of the present disclosure include the following aspects, for example.Aspect 1A thermosensitive recording medium having, in a plan view, a first direction and a second direction perpendicular to the first direction, the thermosensitive recoding medium including a support including a first surface and a second surface opposite to the first surface, a thermosensitive layer arranged in a partial region of the first surface of the support, a protective layer arranged on at least a top surface of the thermosensitive layer, and a cleaning layer arranged in another partial region of the first surface of the support, said another partial region being different from the partial region in which the thermosensitive layer is arranged, in which the first surface of the support includes an exposed part being exposed from the thermosensitive layer, the cleaning layer, and the protective layer, and in a cross-sectional view obtained by cutting the thermosensitive recording medium in the first direction at a predetermined position in the second direction, the thermosensitive layer and the cleaning layer are arranged in different regions.Aspect 2The thermosensitive recording medium according to Aspect 1, in which in the first direction, at least one of a side surface of the thermosensitive layer and a side surface of the protective layer is not in contact with a side surface of the cleaning layer, and the exposed part is between the thermosensitive layer and the protective layer, and the cleaning layer in the first direction.Aspect 3The thermosensitive recording medium according to Aspect 1 or Aspect 2, in which the following relationship is satisfied:(Xc + Xp) / Xs > 0.25FN202501297 where Xc represents a minimum length of the cleaning layer in the first direction, Xp represents a minimum length of the protective layer in the first direction, and Xs represents a maximum length of the support in the first direction.Aspect 4The thermosensitive recording medium according to any one of Aspect 1 toAspect 3, in which the following relationship is satisfied:Xc / Xs > 0.05 where Xc represents a minimum length of the cleaning layer in the first direction and Xs represents a maximum length Xs of the support in the first direction.Aspect 5The thermosensitive recording medium according to any one of Aspect 1 to Aspect 4, further including a color ink layer on the second surface of the support.Aspect 6The thermosensitive recording medium according to any one of Aspect 1 to Aspect 5, further including a color ink layer on the first surface of the support, in which the color ink layer is arranged in at least one manner selected from(1) at least a top surface of the color ink layer is exposed,(2) the thermosensitive layer is arranged on at least a top surface of the color ink layer, and(3) the cleaning layer is arranged on at least the top surface of the color ink layer. Aspect 7The thermosensitive recording medium according to any one of Aspect 1 to Aspect 6, further including a color ink layer on the first surface of the support, in which at least one of the cleaning layer and the protective layer is arranged on an entire surface of at least the top surface of the color ink layer.Aspect 8The thermosensitive recording medium according to any one of Aspect 1 toAspect 7, in which the following relationship is satisfied:Yc = Ys where Yc represents a maximum length of the cleaning layer in the second direction and Ys represents a maximum length of the support in the second direction.Aspect 9The thermosensitive recording medium according to any one of Aspect 1 to Aspect 8, in which the cleaning layer and the protective layer have the same composition.Aspect 10The thermosensitive recording medium according to any one of Aspect 1 to Aspect 9, in which a region where the support and the cleaning layer are laminated has a haze of 30% or less.Aspect 11FN202501297An image recording method, including recording an image on the thermosensitive recording medium according to any one of Aspect 1 to Aspect 10 by using a thermal head. Aspect 12The image recording method according to Aspect 11, in which the recording includes transporting the thermal head in the first direction of the thermosensitive recording medium.

[0343] With the thermosensitive recording medium according to any one of Aspect 1 to Aspect 10 and the image forming method according to Aspect 11 or Aspect 12, it is possible to solve the above-mentioned conventional problems and achieve the object of the present disclosure.

[0344] The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and / or features of different illustrative embodiments may be combined with each other and / or substituted for each other within the scope of the present invention. Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.

[0345] This patent application is based on and claims priority to Japanese Patent Application No. 2024-221199, filed on December 17, 2024, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.[Reference Signs List]

[0346] 1 ... Support1A ... First surfaceIB ... Second surface2 ... Thermosensitive layer3 ... Protective layer4 ... Cleaning layer5 ... Color ink layer100 ... Thermosensitive recording medium

Claims

FN202501297[CLAIMS]1. A thermosensitive recording medium having, in a plan view, a first direction and a second direction perpendicular to the first direction, the thermosensitive recoding medium comprising: a support including a first surface and a second surface opposite to the first surface; a thermosensitive layer arranged in a partial region of the first surface of the support; a protective layer arranged on at least a top surface of the thermosensitive layer; and a cleaning layer arranged in another partial region of the first surface of the support, said another partial region being different from the partial region in which the thermosensitive layer is arranged, wherein the first surface of the support includes an exposed part being exposed from the thermosensitive layer, the cleaning layer, and the protective layer, and in a cross-sectional view obtained by cutting the thermosensitive recording medium in the first direction at a predetermined position in the second direction, the thermosensitive layer and the cleaning layer are arranged in different regions.

2. The thermosensitive recording medium according to claim 1, wherein in the first direction, at least one of a side surface of the thermosensitive layer and a side surface of the protective layer is not in contact with a side surface of the cleaning layer, and the exposed part is between the thermosensitive layer and the protective layer, and the cleaning layer in the first direction.

3. The thermosensitive recording medium according to claim 1 or 2, wherein the following relationship is satisfied:(Xc + Xp) / Xs > 0.25 where Xc represents a minimum length of the cleaning layer in the first direction, Xp represents a minimum length of the protective layer in the first direction, and Xs represents a maximum length of the support in the first direction.

4. The thermosensitive recording medium according to any one of claims 1 to 3, wherein the following relationship is satisfied:Xc / Xs > 0.05 where Xc represents a minimum length of the cleaning layer in the first direction and Xs represents a maximum length of the support in the first direction5. The thermosensitive recording medium according to any one of claims 1 to 4, further comprising:FN202501297 a color ink layer on the second surface of the support.

6. The thermosensitive recording medium according to any one of claims 1 to 5, further comprising: a color ink layer on the first surface of the support, wherein the color ink layer is arranged in at least one manner selected from:(1) at least a top surface of the color ink layer is exposed;(2) the thermosensitive layer is arranged on at least the top surface of the color ink layer; and(3) the cleaning layer is arranged on at least the top surface of the color ink layer.

7. The thermosensitive recording medium according to any one of claims 1 to 6, further comprising: a color ink layer on the first surface of the support, wherein at least one of the cleaning layer and the protective layer is arranged on an entire surface of at least the top surface of the color ink layer.

8. The thermosensitive recording medium according to any one of claims 1 to 7, wherein the following relationship is satisfied:Yc = Ys where Yc represents a maximum length of the cleaning layer in the second direction and Ys represents a maximum length of the support in the second direction.

9. The thermosensitive recording medium according to any one of claims 1 to 8, wherein the cleaning layer and the protective layer have the same composition.

10. The thermosensitive recording medium according to any one of claims 1 to 9, wherein a region where the support and the cleaning layer are laminated has a haze of 30% or less.

11. An image recording method comprising: recording an image on the thermosensitive recording medium according to any one of claims 1 to 10 by using a thermal head.

12. The image recording method according to claim 11, wherein the recording includes transporting the thermal head in the first direction of the thermosensitive recording medium.

Images